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1980-81 Geotech Report Volume Acres
I ME co@ Mai I ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT 1980-81 GEOTECHNICAL REPORT TABLE OF CONTENTS - VOLUME 1 LIST OF TABLES LIST OF FIGURES Page 1 - INTRODUCTION ............................................... 1-1 1.1 - General ............................................. 1-1 1.2 - Project Description and Location .................... 1-1 1.3 - Plan of Study ....................................... 1-2 1.4 - Report Contents ..................................... 1-4 1.5 - Acknowledgements .................................... 1-5 2 - SUMMARY AND CONCLUSIONS ................................... 2-1 2.1 - Introduction ........................................ 2-1 2.2 - Watana Site .. .............. .......,.............. 2-1 2.3 - Devil Canyon Site ................................... 2-4 3 - REVIEW OF PREVIOUS INVESTIGATIONS .......................... 3-1 3.1 - Introduction ........................................ 3-1 3.2 - Watana.............................................. 3-1 3.3 - Devil Canyon ........................................ 3-2 3.4 - Conclusions ......................................... 3-3 4 REGIONAL GEOLOGY .......................................... 4-1 4.1 - Introduction ........................................ 4-1 4.2 - Stratigraphy........................................ 4-1 4.3 - Tectonic History .................................... 4-2 4.4 - Glacial History ..................................... 4-2 5 - SCOPE OF GEOTECHNICAL INVESTIGATION ......... 5.1 - Introduction ........................................ 5-1 5.2 - Geologic Mapping .. 5-1 5.3 - Subsurface Investigation ............................ 5-4 5.4 - Seismic Refraction Surveys .......................... 5-6 5.5 - Borrow Investigation ................................ 5-7 5.6 - Laboratory Testing .................................. 5-8 6 - RESULTS OF GEOTECHNICAL INVESTIGATIONS - WATANA ........... 6-1 6.1 - Watana Damsite...................................... 6-1 6.2 - Relict Channel ........................... 6-1 6.3 - Borrow and Quarry Material .......................... 6-32 7 - RESULTS OF GEOTECHNCIAL INVESTIGATIONS - DEVIL CANYON ...... 7-1 7.1 - Devil Canyon Damsite................................ 7-1 7.2 - Borrow and Quarry Material .......................... 7-27 REFERENCES GLOSSARY i Dacus ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT 1980-81 GEOTECHNICAL REPORT TABLE OF CONTENTS - VOLUME 2 APPENDIX A - Selected Bibliography of Previous Investigations i APPENDIX B - Watana Diamond Core Drilling Logs APPENDIX C - Devil Canyon Diamond Core Drilling Logs APPENDIX D - Watana Water Pressure Testing Details APPENDIX E - Devil Canyon Water Pressure Testing Details APPENDIX F - Watana Borrow Site Investigation F.1 - Borrow Site D F.2 - Borrow Site E F.3 - Borrow Site H F.4 - Borrow Sites I & J I APPENDIX G - Devil Canyon Borrow Site Investigation G.1 - Borrow Site G I APPENDIX H - Seismic Refraction Survey - 1980 APPENDIX I - Seismic Refraction Survey - 1981 l APPENDIX J - Airphoto Interpretation APPENDIX K - Reservoir Slope Stability ii LIST OF TABLES Table No. Title 3.1 Summary of Previous Investigations - Watana Damsite 3.2 Summary of Previous Investigations - Borrow Site D - Watana 3.3 Summary of Previous Investigations - Borrow Sites E, F, and C - Watana 3.4 Summary of Previous Investigations - Devil Canyon Damsite 3.5 Summary of Previous Investigations - Borrow Site G -- Devil Canyon 4.1 Geologic Time Scale 5.1 Summary of the 1980-81 Investigation - Watana Damsite 5.2 Summary of the 1980-81 Investigation - Devil Canyon Damsite 5.3 Summary of the 1980-81 Seismic Refraction Line Data 5.4 Summary of 1980-81 Investigation - Borrow Site D - Watana 5.5 Summary of 1980-81 Investigation - Borrow Site E - Watana 5.6 Summary of 1980-81 Investigation - Borrow Site G - Devil Canyon 5.7 Summary of 1980-81 Investigation - Borrow Site H - Watana 5.8 Summary of 1980-81 Investigation - Borrow Sites I and J - Watana 5.9 Summary of Rock Tests - Watana 5.10 Summary of Rock Tests - Devil Canyon 6.1 Watana Seismic Velocity Correlations 6.2 Watana Joint Characteristics 6.3 Watana RQD Summary 6.4 Watana Borehole Rock Quality Distribution 6.5 Watana Rock Test Summary - Diorite, Quartz -Diorite, Granodiorite 6.6 Watana Rock Test Summary - Andesite Porphyry 6.7 Quaternary Stratigraphy of Buried Channel Area 6.8 Material Properties - Borrow Site D 6.9 Gradation Results - Borrow Site D 6.10 Material Properties - Borrow Site E 6.11 Material Properties - Borrow Site H 6.12 Material Properties - Borrow Sites I and J 7.1 Devil Canyon Seismic Velocity Correlations 7.2 Devil Canyon Joint Characteristics 7.3 Devil Canyon Tailrace Tunnel - Joint Characteristics 7.4 Devil Canyon RQD Summary 7.5 Devil Canyon - Borehole Rock Quality Distribution 7.6 Devil Canyon Rock Vest Summary - Mafic Dikes and Argillite 7.7 Devil Canyon Rock Test Summary - Graywacke 7.8 Material Properties - Borrow Site G iii LIST OF FIGURES Figure No. Title 1.1 General Location Map 1.2 Watana General Arrangement 1.3 Devil Canyon General Arrangement 4.1 Regional Geology Map 5.1a Watana: Damsite Vicinity Exploration Map 5.1b Watana: Exploration Map 5.2 Devil Canyon Exploration Map 5.3 Borehole Typical Instrumentation 5.4 Borehole Typical Instrumentation 6.1 Watana Index Map 6.2 Watana Top of Bedrock and Surficial Geologic Map 6.3 Watana Geologic Map 6.4 Watana Geologic Section W-1 6.5 Watana Geologic Section W-2 6.6 Watana Geologic Section W-3 6.7 Watana Geologic Section W-4 6.8 Watana Geologic Section W-5 6.9 Watana Andesite Porphyry Flow Structure and Inclusions 6.10 Watana Fracture Zone in Andesite Porphyry 6.11 Watana Felsic Dike in Diorite 6.12 Watana Joint Station Plots 6.13 Watana Composite Joint Plots 6.44 Watana Typical Shear 6.15 Watana Shear/Alteration Zone 6.16 Watana "The Fins" 6.17 Watana Geologic Features GF4A, GF4B, and GF5 6.18 Watana Geologic Features Downstream of Centerline 6.19 Watana "Fingerbuster" Area North Bank 6.20 Watana Geologic Feature GF7B 6.21 Watana Rock Tests 6.22 Watana Static Elastic Properties for Andesite and Diorite 6.23 Watana Direct Shear Tests 6.24 Watana Unconfined Compressive Strength Test Results 6.25 Watana Point Load Test Data 6.26 Watana Rock Permeability 6.27 Watana Thermistor Data 6.28 Watana Thermistor Data - Relict Channel 6.29 Watana Thermistor Data - Borrow Site H and Borrow Site D 6.30 Watana Relict Channel Photos 6.31 Watana Relict Channel Section 6.32 Watana Relict Channel and Borrow Site D/Stratigraphic Fence Diagram Sheets 6.33 Watana Relict Channel - Expanded Thalweg Section 6.34 Watana Relict channel Profiles ACRE LIST OF FIGURES (Cont'd) Figure No. Title 6.35 Relict Channel - Top of Bedrock 6.36 Watana Quarry and Borrow Sites Index Map 6.37 Watana Quarry Site A - Plan and Sections 6.38 Quarry Site B - Plan and Sections 6.39 Borrow Sites C and F 6.40 Borrow Site D - Plan 6.41 Watana Borrow Site D - Range of Gradations 6.42 Watana Borrow Site D - Material Gradation Types 6.43 Borrow Site E - Plan 6.44 Borrow Site E - Sections 6.45 Watana Borrow Site E - Range of Gradations 6.46 Watana Borrow Site E - Stratigraphic Unit Gradations 6.47 Borrow Site C and F - Range of Gradations 6.48 Borrow Site H - Plan 6.49 Watana Borrow Site H - Range of Gradations 6.50 Watana Borrow Site H - Stratigraphic Unit Gradations 6.51 Borrow Site I - Plan 6.52 Borrow Site J - Plan 6.53 Borrow Sites E, I, and J - Photos and Typical Sections 6.54 Quarry Site L - Plan and Sections 7.1 Devil Canyon Index Map 7.2 Devil Canyon Top of Bedrock and Surficial Geologic Map 7.3 Devil Canyon Geologic Map 7.4 Geologic Sections DC-1 7.5 Geologic Sections DC-2 7.6 Geologic Sections DC-3 7.7 Geologic Sections DC-4 7.8 Geologic Sections DC-5 7.9 Geologic Sections DC-6 7.10 Geologic Sections DC-7 7.11 Devil Canyon Typical Ar gillite/Graywacke 7.12 Devil Canyon Aerial View of Site 7.13 Devil Canyon Joint Plots 7.14 Devil Canyon Tailrace Geology 7.15 Devil Canyon Rock Tests 7.16 Devil Canyon Static Elastic Properties for Argillite and Graywacke 7.17 Devil Canyon Direct Shear Tests 7.18 Devil Canyon Unconfined Compressive Strength Test Results 7.19 Devil Canyon Point Load Test Data 7.20 Rock Permeability 7.21 Thermistor Plots - Damsite 7.22 Borrow Site G - Plan 7.23 Borrow Site G - Sections 'AID ., LIST OF FIGURES (Cont'd) Figure No. Title 7.24 Devil Canyon Borrow Site G - Range of Gradations 7.25 Devil Canyon Borrow Site G - Stratigraphic Unit Gradations 7.26 Devil Canyon - Quarry Site K vii rCR� 3 f t I 1 - INTRODUCTION 1.1 - General The Susitna Hydroelectric Project is located within the upper reaches of the Susitna River basin in south-central Alaska (Figure 1.1). The feasibility studies for hydroelectric development were performed by Acres American Incorporated (Acres) under contract to the Alaska Power Authority (The Power Authority). The overall objectives of the study were: - To determine technical, economic and financial feasibility of the Susitna Hydroelectric Project to meet the future power needs of the Railbelt Region of the state of Alaska; - To examine the environmental consequences of constructing the Susitna Hydroelectric Project; - To file a license application with the Federal Energy Regulatory Com- mission (FERC) should the project be deemed feasible. As part of the Plan of Study (POS), a geotechnical exploration program (Task 5) was undertaken at the proposed project locations at Watana and Devil Canyon. The purpose of this report is to present a detailed des- cription of the geologic and geotechnical conditions at these sites. 1.2 -- Project Description and Location The Watana and Devil Canyon sites had been previously identified by the U.S. Army Corps of Engineers (COE ) and the U.S. Bureau of Reclamation (USER) over a period of years from 1952 to 1979. The scheme calls for a large embankment dam with an underground power- house at Watana and a high concrete dam with underground powerhouse at the Devil Canyon site. General site arrangements are shown in Figures 1.2 and 1.3. The area of study is located within the Coastal Trough Province of south-central Alaska, with a drainage of approximately 6,000 square miles. The Susitna River is glacier -fed, with headwaters on the south- ern slope of the Alaska Range. From its proglacial channel in the Alaska Range, the Susitna River passes first through a broad, glaci- ated, intermontane valley of knob and kettle and braided channel topo- graphy. Swinging westward along the edge of the Copper River lowlands, it enters the deep U-shaped valleys which include the proposed dam - sites, winding through the Talkeetna Mountains until it emerges into a broad glacial valley leading to Cook Inlet near Anchorage. 1-1 ACNES The Watana site is located at approximately river mile 184 between Tsusena and Deadman Creeks. The Watana damsite is located in a rela- tively broad U-shaped valley rising in steps, with a steep lower por- tion breaking into somewhat flatter slopes and becoming much gentler near the top. Access to the lower sections is limited by vertical rock outcrops. Gravel bars, some of which are quite wide, are exposed in the river bed during low water flows. The river at this site is approximately 500 feet wide and is relatively turbulent and swift flow- ing. The Devil Canyon site is located on the Susitna River 14 miles upstream from the Alaskan Railroad, 140 miles north of Anchorage, and 160 miles south of Fairbanks. The site is located at approximate river mile 152 (32 river miles downstream from the Watana site). At the Devil Canyon site, the river enters a very narrow "V-shaped gorge about two miles in length with steep walls up to 600 feet high. The damsite is several hundred feet downstream from the entrance of Devil Canyon. The valley is generally asymmetrical in shape, with the north abutment sloping at about 45' and the south abutment steeper, about 70°. The south abut- ment displays overhanging cliffs and detached blocks of rock. The north abutment is somewhat less rugged in the upper half, the lower portion is very steep. Access at river level is very limited, but nar- row benches are accessible at low water levels. The Susitna River in Devil Canyon is approximately 150 feet wide and very turbulent. The canyon itself is approximately 1,000 feet wide at the proposed dam crest elevation. 1.3 - Plan of Study (a) Objectives The objectives of the Task 5 studies were to determine the surface and subsurface geology and geotechnical conditions for the feasi- bility of: - A large rockfill dam, underground powerhouse, and associated structures at Watana site; - A concrete dam with underground powerhouse and associated struc- tures at Devil Canyon site; - Transmission line to connect the proposed development with the existing power grid system; and Access roads to the proposed development. (b) Scope The task was subdivided into a series of subtasks to meet the overall objectives. The subtasks and their corresponding objec- tives were: ACM 1 z Subtask 5.01 - Data Collection and Review 5.02 - Airphoto interpretation Objectives To collect and review all existing geological and geotechnical data pertaining to the project includ- ing the access road and transmis- sion line corridors and the upper Susitna River basin. Perform airphoto interpretation and terrain analysis of the Watana and Devil Canyon damsite area, reservoir areas, borrow sites and access road, and transmission line corridors, and identify adverse geological features and geotechni- cal conditions that could signifi- cantly affect the design and con- struction of -project structures. 5.03 - Exploratory Program Design the geotechnical explora- Design (1980) tory investigation programs for 1980 for Watana and Devil Canyon damsites, dam construction materi- als, and reservoir areas, and along the access road route. 5.04 - Exploratory Program (1980) 5.05 - Exploratory Program Design (1981) 5.06 - Exploratory Program (1981) 1-3 Perform initial surface and sub- surface program investigations at Watana and Devil Canyon sites and reservoir areas and access road routes to establish general and specific geological and foundation conditions. Design the geotechnical explora- tory investigation program for 1981 for Watana and Devil Canyon damsites, dam construction materi- als and reservoir areas, and for the selected access road and transmission line routes. Complete surface and subsurface investigations at Watana and Devil Canyon damsites, reservoir areas, access roads, and transmission line routes to the extent neces- sary to provide adequate data to confirm project feasibility and for submission of FERC license application, currently scheduled for September 1982. 5.07 - Exploratory Program Design (1982-1984) 5.08 - Data Compilation (c) Approach Design of the geotechnical explor- atory investigation program for 1982 to 1984 to obtain basic design data for Watana damsite, dam construction materials, and reservoir areas, and for the sel- ected access road and transmission line routes. Assemble all geotechnical explora- tory data into documents suitable for inclusion in relevant project reports and licensing documenta- tion. To meet the objectives of the task in an orderly and timely man- ner, the geotechnical exploratory programs were divided into three stages: the 1980 activities, the 1981 activities, and the activi- ties during and after 1982 (after the FFRC license application is submitted). The 1980 geotechnical activities were planned to identify and investigate in limited detail, those geological and geotechnical conditions which had been identified by previous studies that may have an effect on the feasibility of the project. These activities included Subtasks 5.01 through 5.04. Subtasks 5.05 through 5.08 were undertaken during 1981 and early 1982, respectively. Under these activities, a more detailed study was made of those geological and geotechnical conditions identi- fied during the 1980 studies as warranting further investigation. The 1981 program also included the investigation for the access roads and the transmission lines. These data were subsequently inputs into other task activities for final presentation. It should be noted that the findings and conclusions presented in this report are based on a limited scope of geotechnical investi- gation and that more detailed investigations will be undertaken in the subsequent phases of the project. 1.4 - Report Contents This Oeotechnical Report is presented in seven sections. A summary and preliminary conclusions of the studies are presented in Section 2; a review of previous work undertaken by the COE, USBR, and others is pre- sented in Section 3; a preliminary assessment of regional geology is in Section 4; the scope of the 1980-81 geotechnical exploration program is presented in Section 5; and the results of the study in Sections 5 and 7. A comprehensive bibliography of geotechnical information for the site area was compiled during Subtask 5.01 and is presented in Appendix A. Detailed results of drilling, testing, seismic refraction surveys, 1-4 airphoto interpretation and reservoir mapping performed during the pro- ject are included in Appendices B through K. Engineering significance and application of the data developed in Task 5 and presented in this report have been addressed in the Susitna Feasibility Report (1). This study, therefore, stands as a referenced document to that report. 1.5 - Acknowledgements Some material presented in this report has been obtained from reports previously published by the USBR and others. The cooperation of the COE in providing access to records and data and opinions on interpreta- tion is gratefully acknowledged. Drilling at the sites was performed by The Drilling Company (TDC) and Interstate Exploration, Inc., under the direct supervision and direc- tion of Acres staff and R&M Consultants, Anchorage, Alaska. Seismic refraction surveys were performed by Woodward -Clyde Consultants. In - hole geophysical logging work was by EDCON (Exploration Data Consul- tants, Inc., of Denver, Colorado). Airphoto interpretation was done by R&M Consultants, and laboratory testing by R&M and Acres. Logistical support during field activities was provided by KNIK/ADC - Joint Venture under its subcontract with Cook Inlet Region, Inc./Holmes & Narver, Inc., and Acres for camp accommodations, and by Akland Heli- copters, ERA Helicopters, Air Logistics, Inc., also under subcontract with Acres, for personnel and equipment transportation requirements. The results of these activities were presented to the Acres External Review Panel (Dr. R. Peck, Dr. S. Hendron, Mr. M. Copen), to the Power Authority, and to the Power Authority Review Board Members (Dr. H. Seed and Dr. A. Merritt) during technical meetings and discussions. Acres is very grateful for their critical and very objective review of the information. Thanks are due to Mr. L. A. Rivard for his contributions to Subtask 5.02 - Airphoto Interpretation. 1-5 KEY MAP LEGEND PRIMARY PAVED UNDIVIDED HIGHWAY SECONDARY PAVED UNDIVIDED HIGHWAY ^----- SECONDARY GRAVEL HIGHWAY • Y-�- RAILROAD -- - RIVER 0 20 40 MILES SCALE FIGURE 1.1 �11�� ly4-Y---lr GALLERY ACCESS TUNNEL r 51 ci � 15 W W 51 r F 7 ti 51 w � � w F w W 5 /N 3225,000 1 - y y 4 MAIN POWERHOUSE 2.2-90 5 ACCESS ROAD ,i e 1 11 1 y 2 4 1 y 50 1 N 3,226 000 11 \g6O Zp30 � 1 950 11 ;��= 1-(Op 4 4900- ~--�... i ALL RYrA,C-C SS \6 ~ 1850 1800� 115 ! n AIN L ET E OUTL/ \6\0 1� O y'IpO� I 1 CREST L 472 CREST OF DAM D TC1N{AGE 2l EL, 2210 _ H32:27,000 - COFFERDAM DOWNSTREAM S�Sy1aP } j GALLERY .ACCESS TUNNEL DOWNSTREAM TUNNEL PORTALS 1 y51 r� T -ACCESS-.TUNNEL CRES EL.I I 11� GROUTING DRAINAGE— �}��NP�JRjAL `f-rll--- _ / ! -- // ! \� GALLERY DIVERSION TUNNELS r r N 3.220,000 , MAIN $PiLLWAY lt-� UPSTREAM COFFERDAM - DIVERSION —- INTAKES O� 1 C151, O ho' \ \� SCALE 0 200 400 FEET OUTLET FACILIT4E INTAKE / it INTAKE it ' TAKE POWER INTAKE PPROACH CHAN � N3,229,000 li WATA N A GENERAL ARRANGEMENT FIGURE 1.2 ��Rfs ..:....:.:...... 'Aw 2 - SUMMARY AND CONCLUSIONS 2.1 - Introduction The following subsections present the main findings and conclusions of the 1980-81 geotechnical study for the Watana and Devil Canyon sites. 2.2 - Watana Site (a) Results of Study - Bedrock at the damsite is a large granitic pluton consisting of a quartz diorite, diorite and granodiorite. An andesite por- phyry, an extrusive volcanic rock, is exposed immediately down- stream from the damsite. - Where mapped and drilled, the contact between the diorite and andesite is generally a highly fractured, weathered, poor qual- ity rock. The contact zone ranges from 2 to 15 feet, but is gen- erally less than 10 feet. - Two major and two minor joint sets were mapped at the damsite. These are in the order of most to least pronounced: (a) strike 320°, dip near vertical; (b) strike 0450-0800, dip near verti- cal; (c) strike 340°-030°, with dips between 40' east to 65' west; and (d) strike 080" with low angles of dip. - Two pronounced sheared and highly fractured zones named "The Fins" and "Fingerbuster" have been mapped immediately upstream and downstream from the damsite. - Small localized fractured, sheared, and altered zones have been mapped within the damsite. These zones average up to 10 feet wide. No evidence of recent faulting was found. - A large altered and sheared zone up to 300 feet wide was mapped on the upper left abutment of the main dam. - The riverbed is filled with alluvium consisting of gravels, cobbles, and boulders in a matrix of sand and silty sand ranging from 40 to 80 feet, and may exceed 100 feet in depth in places. - Overburden thickness at the damsite is generally shallow ranging from 50 to 60 feet on the upper abutment to 0 on the steeper rock slopes. Overburden generally consists of glacially derived silts, sands, and boulders and talus. ,., AC�IS �i - Rock quality at the damsite is good to excellent with average rock quality designations (RQDs) ranging from 75 to 90 percent. Below the upper 20 to 40 feet of weathered rock, rock quality tends to improve. - Rock strengths are high with an average unconfined compressive strength greater than 20,000 psi. - The rock ma$s has, in general, a low permeability with an aver- age of 10- cm/sec below the weathered zones. Higher perm- eabilities are found in the more highly fractured and sheared zones. - Groundwater at the damsite is a subdued replica of the topo- graphy. Groundwater table on the right abutment is deep, on the average of 110 to 280 feet. Groundwater conditions on the left abutment are complicated by the apparent deep and continuous permafrost. A perched groundwater table exists on top of the permafrost. Artesian conditions were encountered at depth on this abutment within the thick alteration zone beneath the perm- afrost. - Permafrost appears to be continuous in the bedrock throughout the left abutment, reaching a depth of 200 to 300 feet. Al- though no permafrost was encountered on the right abutment, localized sporadic permafrost may be present. - A relict channel exists on the right abutment extending from Deadman Creek to Tsusena Creek. The thalweg reaches Elevation 1,800 (400 feet below maximum pool elevation). The width of the relict channel at the upstream face is about 15,000 feet. In- vestigations in and adjacent to the channel show that it is filled with a sequence of alluvial materials overlain by a se- quence of glaciofluvial silts, sands and clays. The average hydraulic gradient through the channel at maximum reservoir level is estimated to be approximately-10 percent. The perme- abilities within the channel are variable with high permeabili- ties in the coarser bouldery strata and lower permeabilities in the river silts, clays, and lacustrine deposits. Perched water tables, aquicludes and localized permafrost exist throughout the channel. - Bedrock surface drops below the maximum pool elevation on the left bank approximately 2 miles upstream from the damsite in the area of Fog Lakes. Based on seismic velocity measurements, bed- rock was estimaed to be below reservoir level over a distance of approximately 9,500 feet. The nearest drainage from this area is Fog Creek, a distance of 5 miles southwest from the reser- voir. ACRES2-2 (b) - The riverbed is filled with alluvium consisting of gravels, cob- bles, and boulders in a matrix of sand and silty sand ranging from 40 to 80 feet, and may exceed 100 feet in depth in places. - Ten potential borrow and quarry sites were identified for poten- tial construction material. Several of these sites, which had been delineated in previous studies, were eliminated from fur- ther consideration because of lengthy haul distances, more locally available material, or insufficient volume. Those sites considered as primary borrow and quarry sources are: . Rock fill - Quarry Site A; . Impervious and semi -pervious material - Borrow Sites 0 and H; . Pervious material - Borrow Sites E and I; and . Construction gravel and fill - Borrow Site F. - Areas of existing and potential slope instability and erosion, as well as areas of permafrost were delineated within the Watana reservoir. Conclusions Based on these findings, the following conclusions regarding the Watana site can be made: - No geologic or geotechnical conditions were found to affect the feasibility of an embankment dam at the site. - The significant geologic features "The Fins" and "Fingerbuster" are considered unsuitable rock for construction of surface and underground facilities and should be avoided if at all pos- sible. - Subsurface exploration at the damsite shows that rock quality on the right abutment is suitable for the construction of large underground facilities. Localized sheared, fractured, and altered zones are likely to be encountered during underground excavation; however, it is considered that these features are of limited extent and could be handled by conventional construction procedures. - There is an altered and fractured zone on the left abutment downstream from the main dam. Any structure sited on this zone would incur high costs for excavation and treatment. - Although localized zones of sheared and fractured rock were en- countered in all borings, no evidence of major faulting was found in either the riverbed or within the damsite area. 2-3 lacAfs - Further investigations of the material within the relict channel will be required to accurately define its properties, strati- graphy, permeability, and extent of permafrost for the purpose of assessing potential reservoir seepage and behavior under earthquake conditions. - Suitable types and adequate amounts of borrow and quarry materi- al were found near the damsite. - Although local slumps and landslides will probably occur in many areas of the reservoir, there appear to be no potentially large landslides which might pose a threat to the dam. 2.3 - Devil Canyon (a) Results of Study The following geologic and geotechnical conditions have been iden- tified at the Devil Canyon site: - The proposed damsite is underlain by a metamorphic argillite and graywacke rock. - The bedrock has been intruded by a series of mafic and felsic dikes which crosscut the damsite. The contacts of the dikes with the host rock are welded with some secondary localized shearing or fracturing occurring at or near the contact. - Two major and two minor joint sets have been mapped in the dam - site area. These are, in the order of most to least pronounced: (a) strike 340°, dip near vertical; (b) strike 0200 to 100% dip from 550 southeast to 750 north; (c) strike 060' to 080°, dip to northwest; and (d) strike northeast to east with low angle dips. Average joint spacing for the most prominent set is 1.5 to 2 feet. - Localized sheared and fractured zones ranging from 1 to 3 feet wide have been mapped at the damsite. - A highly sheared and fractured zone was found to parallel the river beneath the proposed saddle dam on the left abutment, A boring through this feature encountered breccia and gouge up to 3 feet wide. The east -west extent of this feature could not be accurately determined; however, based on surface topography, it is estimated to be no greater than 1,500 feet• long. - Stress relief joints were mapped up to 100 feet back from the damsite gorge walls on the left abutment. - A marked drop off in bedrock elevation was noted in previous in- vestigations along the eastern portion of Borrow Site G approxi- mately 1,000 feet upstream from the damsite. Land access res- trictions imposed during this study prohibited any further in- vestigation at this feature. Work, however, performed in proxi- mity to this area showed no compelling evidence for this feature to be a fault. - Minor fractures and shear zones ►sere encountered in several of the boreholes in the river; however, these were limited in ex- tent and could not be correlated between borings. No indication was found of faulting beneath the river or of recent faulting anywhere at the damsite. - Rock quality at the damsite was good to excellent with an over- all RQD greater than 80 percent. - Rock strengths are high, averaging approximately 20,000 psi. Roc permeabilities are low, ranging from 1 x 10-4 to 1 x 10- cm/sec with the lower permeabilities occurring in the more highly fractured and sheared zones. Based on preliminary data, groundwater levels appear to be vari- able across the site, principally controlled by the degree of fracturing within the rock mass. Readings in boreholes and pie- zometers show water levels range from near surface above the break in slope to as deep as 120 feet on the north abutment. No permafrost was found in the main damsite area. - Borrow Site G, located approximately 1,000 feet upstream from the damsite, has been identified as the principal source for concrete aggregate and fill material. Quarry Site K, located on the left bank downstream from the damsite, has been identified as the principal source for rockfill; and Borrow Site D, adja- cent to the Watana site, has been identified as the principal source for impervious and semi -pervious material. (b) Conclusions Based on these findings, the following conclusions have been made regarding the Devil Canyon site: - No geologic or geotechnical conditions were found at the Devil Canyon damsite that would adversely affect feasibility for the construction of a concrete arch dam. 2-5 RCRfs - Rock quality was considered suitable for the construction of underground power facilities, including a powerhouse and related structures. - Localized sheared and fractured rock is likely to be encountered during underground excavation; it is considered that these fea- tures are of limited extent and could be handled by conventional construction procedures. - Suitable types and quantities of borrow material have been iden- tified for this study for dam construction. - The abrupt drop-off in bedrock east of the damsite beneath Bor- row Site G, as well as the shear and fracture zones beneath the saddle dams, will require additional investigation in subsequent phases of study. However, these features are not expected to have an impact on site feasibility. - Although no permafrost was found during explorations, sporadic permafrost may exist at the site. - There are no known areas that could result in significant leak- age or slope instability in the reservoir. ACRES 2e 3 - REVIEW OF PREVIOUS INVESTIGATIONS 3.1 - Introduction The development of the Susitna Hydroelectric Project has been studied by several federal and private agencies in the last 30 years. However, it was not until the late 1950s that any geotechnical investigations were conducted. Between June 1957 and August 1958, the USBR performed geologic mapping and drilling investigations at the Devil Canyon site and limited geo- logic mapping at the Watana site (51). Subsequently, during the 1970s, the COE performed additional investiga- tions at both sites. These included seismic refraction surveys at Devil Canyon, and detailed geologic mapping, seismic refraction survey, diamond and auger drilling, and material testing at the damsite and po- tential borrow sites at Watana. This report briefly discusses the findings of these investigations as documented by the USBR and COE. These reports, which are identified in the bibliography (Appendix A), are available from the Power Authority and Acres for reference. 3.2 - Watana The preliminary reconnaissance work by the USBR in the 1950s was ex- panded during the 1970s by the COE investigations of the damsite, reservoir, and potential borrow sites. The location and extent of the investigations in the main dam area are shown in Figure 5.1. Detailed investigations in the borrow sites are presented in Section 6.3. In 1975, a total of 22,500 linear feet of seismic refraction surveys was performed by Dames & Moore (12) for the COE in their initial feasi- bility report. This was expanded by Shannon & Wilson (39) in 1978 with an additional 47,665 feet of survey. This work served to support the results of the drilling and mapping programs (Figure 5.1). During the 1978 season, the site was explored with 28 diamond and ro- tary drill holes (both vertical and inclined) ranging from 30 to 600 feet in length (Table 3.1). Six of the diamond drill holes were locat- ed in the river bottom and reached a maximum of 520 feet into rock. Five borings were drilled on the left abutment and six on the right, reaching a maximum depth of 300 feet or an elevation of 1560. On the right bank, eleven boreholes were located in what was identified as a deep, relict channel to determine the thickness and characteristics of the overburden, the depth of the water table, and the permafrost condi- tions. These boreholes were also designed to obtain samples of poten- tial borrow materials and to evaluate bedrock depth to control spillway location. A total of six potential quarry and borrow sites were identified for construction material. Of these, four borrow sites were explored with 27 backhoed test pits and 24 auger borings (Tables 3.2 to 3.3). These areas included Borrow Site D on the right abutment, Borrow Site E lo- cated approximately 15,000 feet downstream from the dam, and Borrow Site F located on Tsusena Creek three miles upstream from its conflu- ence with the Susitna River (Section 6.3). Geologic mapping was conducted in the damsite area to delineate major structural features. A limited laboratory testing program was conducted on potential borrow material from the various borrow sites to establish the indexes and engineering characteristics of the borrow materials. These tests in- cluded determination of grain size distribution, permeability, triaxial shear tests, Modified Proctor compaction tests, concrete aggregate tests, and petrographic analyses (46,48). The COE also installed a series of ten open -well piezometers and thir- teen temperature -logging casings in boreholes. 3.3 - Devil Canyon The bulk of the previous geotechnical investigation for Devil Canyon was performed by the USBR between June 1957 and August 1958 (51) as shown in Figures 5.2 and 7.22. A total of 21 diamond drill borings were drilled in the damsite area. Six holes, drilled to depth of 50 to 110 feet were located on the left abutment. Four holes were drilled near the dam axis on the upper abutment to a maximum depth of 150 feet. The remaining 12 boreholes were drilled along the riverbed (Table 3.4). Fourteen test pits were dug in the alluvial fan and terrace deposits immediately upstream from the dam axis (Table 3.5). Four rock benches were excavated on the dam abutments to define rock conditions. Laboratory tests, including gradation determinations and petrographic analysis, were conducted on samples of the borrow site materials to determine their suitability for use as concrete aggregate. Representa- tive rock samples from the abutments were examined petrographically to determine mineralogy and tested to determine compressive strength, elasticity, absorption, and porosity of the 'foundation material. During 1978, Shannon & Wilson (39), under COE contract, ran three seis- mic refraction lines totalling 3,300 feet in the borrow site and along the proposed saddle dam to expand the drilling information (Figures 5.2 and 7.22). This survey, along with sampling of the alluvial fan mater- ial, was the only work COE performed at the site during their 1978-1979 investigation. ��REsI 3_ 3.4 - Conclusions The investigations conducted by the COE and USSR were the first detail- ed efforts to establish the feasibility of the project. A brief sum- mary of their investigation is stated below: (a) Watana Based on the COE work, the Watana site was found suitable for an earthfilled dam. The following is a brief summary of the COE's findings and conclusions relative to the site geotechnical condi- tions: .......... (1) The river valley is filled with alluvium consisting of gravels, cobbles, and boulders in a matrix of sand or silty sand ranging in depth from 40 to 80 feet thick, and may be exceeding 100 feet in places. Overburden on the valley slopes ranges from 0 to 60 feet thick with an average of 10 to 20 feet. (2) Underlying bedrock is fresh, hard -to -very hard diorite, gran- odiorite, and quartz diorite with local andesite porphyry dikes and more widely scattered minor felsite dikes. (3) Fractures are closely spaced on the surface becoming more widely spaced with depth. Deep fractures are generally heal- ed. (4) The prominent jointing and shearing direction is northwest trending with steep dips. Many fractures have thin clay gouge seams and slickensides. (5) No major fault or significant change in material was found beneath the river. (6) Andesite porphyry, an extrusive rock, was mapped slightly downstream from the damsite on the left abutment. The con- tact between this rock and the diorite was not defined. (7) Two prominent shear zones named "The Fins" and "Fingerbuster" were mapped as exposures in the damsite area. Both of these zones trend northwest with strikes from 3000 to 320' and dip between 70' to 90' southwest and northeast. (8) A relict channel was found on the right abutment upstream from the damsite. Material in the channel consists of a mix- ture of glacial tills, glaciofluvial and lacustrine deposits, reaching a depth greater than 450 feet deep at its deepest known point. -3 ACRl3 (9) Deep permafrost was found on the left abutment. (10) Permafrost in the relict channel, although found within one foot of the surface, is expected to be confined to a rela- tively shallow layer. (11) Geology within the reservoir is complex and consists of vari- able thicknesses of surficial tills; glaciofluvial outwash; lacustrine material; and alluvium overlying igneous and meta- morphic rocks, schists, volcanics, and granites. (12) Potentially suitable borrow material was found near the dam site. Material from Borrow Site D on the right abutment was classified as semi -pervious to impervious core material. Material from Borrow Site E from the alluvial deposit down- stream from the dam axis was identified as a potential source for clean aggregate and filter material. (13) Two potential quarry sites were identified as sources of rockfill, riprap, and coarse filter materials. The rock in both sites was classified as diorite and of good quality. (b) Devil Canyon The previous investigations suggested that the Devil Canyon site would be feasible for the construction of a high concrete gravity or thin arch dam with an underground powerhouse. A brief summary of the geotechnical conditions found by the USBR and COE are high- lighted below. (1) Bedrock at the site is an argillite with occasional beds of graywacke. The rock is hard and brittle and contains numer- ous quartz stringers. (2) Stratigraphy strikes approximately east -west with a dip of 45' to 75' south. Three joint sets were defined with the master set striking approximately 335° and dipping from 750 east to vertical. Joint spacing ranges about 4 to 5 feet apart. (3) Several well -developed shears or fault zones occur on both sides of the river and strike generally 335° and dip 80' northeast to vertical. (4) No permafrost was found at the damsite. (5) Shearing was found both normal and parallel to the canyon rim on the south abutment. (6) Large detached blocks of rock up to 25 feet by 50 feet were observed on the left abutment. ACNES3-4 (7) A deep, buried channel was found striking approximately east - west beneath the lake -filled depression on the south abut- ment. This depression may be underlain by a fault or shear zone. (8) River alluvium and water depth appears to be approximately 85 feet deep at the site. (9) No faulting was found beneath the river. (10) Rock conditions were considered suitable for underground ex- cavations. (11) The alluvial fan upstream from the site was found to contain acceptable borrow material for concrete aggregate. (12) Seismic refraction shows an unexplained steep slope of the bedrock surface beneath the alluvial fan. This drop-off occurs over a horizontal distance of approximately 500 feet. 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References (28, 29, and 51) 4 - REGIONAL GEOLOGY 4.1 - Introduction The Devil Canyon and Watana damsites lie in the Susitna River basin within the Talkeetna Mountains of south-central Alaska. The regional stratigraphy, structure, and glacial history are briefly discussed in this section. A more detailed discussion of specific regional tecton- ics is presented in the Woodward -Clyde Consultants` report (58). The geologic setting of the Talkeetna Mountains and the adjacent Susit- na River basin has been interpreted as an enormous tectonic mosaic com- posed of separate continental structural blocks and fragments that accreted to the North American plate during Mesozoic time (7,11,25,27, 38). The exact number of these blocks is unknown; however, geologic and geophysical evidence suggest that the blocks moved northward a con- siderable distance prior to collision with the North American plate (22,33,42). This geologic history is reflected by the highly complex structure and stratigraphy found throughout the region. 4.2 - Stratigraphy The oldest rocks which outcrop in the region are a metamorphosed upper Paleozoic (Table 4.1) rock sequence which trends northeastward along the eastern portion of the Susitna River basin (Figure 4.1). These rocks consist chiefly of coarse to fine grained clastic flows and tuffs of basaltic to andesitic composition, locally containing marble inter - beds (8). This system of rocks is unconformably overlain by Triassic and Jurassic metavolcanic and sedimentary rocks. These rocks consist of a shallow marine sequence of metabasalt flows, interbedded with chert, argillite, marble, and volcaniclastic rocks. These are best expressed in the project area around Watana and Portage Creeks. The Paleozoic and lower Mesozoic rocks are intruded by Jurassic plutonic rocks composed chiefly of granodiorite and quartz diorite. The Juras- sic age intrusive rocks form a batholithic complex of the Talkeetna Mountains (8). The uplift of the Talkeetna Mountains and subsequent rapid erosion associated with this plutonic event, resulted in the deposition of a thick turbidite sequence of argillite and graywackes during the Creta- ceous. These rocks underlie a large part of the project area and form the bedrock at the Devil Canyon site (10). These rocks were subse- quently deformed and intruded by a series of Tertiary age plutonic rocks ranging in composition from granite to diorite in composition and includes related felsic and mafic volcanic extrusive rocks. The Watana site is underlain by one of these large plutonic bodies, which appears to comprise the southern limit of the diorite pluton which predominates along upper Tsusena Creek (6). These plutons were subsequently in- truded and overlain by felsic and mafic volcanics. Mafic volcanics, composed of andesite porphyry lie downstream from the Watana site. a 1 AC�IS The Acres geologic mapping program was performed in three phases: 1980 summer, 1980/81 winter, and 1981 summer. The geologic map- ping program for each phase was initiated by aerial reconnaissance followed by a walking ground traverse. The principal objective of the 1980 program was to perform general reconnaissance mapping of the damsites and reservoirs to: - Verify existing data; - Locate potential borrow and quarry sources and refine limits and and quantity estimates; and - Identify areas that would require detailed mapping during the next two phases of the program. Data from the 1980 program were plotted on 1:6000 scale aerial photographs. The mapping was performed by a team of two geolo- gists during the period of June through August. The 1981 winter program was performed during the month of March and consisted of mapping those areas along the Susitna River and Tsusena and Cheechako Creeks that were not accessible during the warmer months. However, poor ice conditions at Devil Canyon pre- cluded mapping of several areas along the Susitna River. Particu- lar attention was directed to mapping the extent and configuration of "The Fins" and "Fingerbuster" at the Watana site. Similarly, other sheared, fractured, and altered zones were mapped along the river where access could not be gained during the summer months. Mapping consisted of identifying each outcrop and noting its size, orientation, weathering characteristics, lithology, and jointing, as well as any other significant geologic feature. All signifi- cant features were photographed. The 1981 summer program entailed detailed mapping of both dam abutments at Watana and Devil Canyon with particular attention directed at defining the extent of any unusual geologic feature denoted in the previous phases of the investigation. The extent of the detailed mapping program is shown in Figures 6.3 and 7.3. Mapping at Watana extended for approximately 3,000 feet upstream and 3,000 feet downstream from the proposed dam axis. Mapping was performed in those areas having bedrock exposure. For the most part, this was limited to the valley wails. Mapping at Devil Can- yon extended for approximately 2,000 feet upstream and 2,500 feet downstream from the proposed dam. Most of the mapping was con- fined to the gorge walls, since very little outcrop exposure exists beyond the break in slope. Mapping was performed by the "tape and Brunton" method with key areas being marked for future survey control. Mapping of the gorge walls was performed by geo- logists trained as technical climbers. At least three periods of glaciation have been delineated for the region based on the glacial stratigraphy (30,34). During the most recent period (late Wisconsinian), glaciers filled the adjoining low- land basins and spread onto the continental shelf (30). Waning of the ice masses from the Alaska Range and Talkeetna Mountains formed ice barriers which blocked the drainage of glacial meltwater and produced proglacial lakes. As a consequence of this repeated glaciation, the Susitna and Copper River basins are covered by varying thicknesses of tills and lacustrine deposits. 4-3 TABLE 4.1: GEOLOGIC TIME SCALE MILLION OF ERA PERIOD EPOCH GLACIATION YEARS AGO Quaternary Holocene Wisconsinian Pleistocene Illinoian Kansan Nebraskan 1.0 Cenozoic Pliocene Miocene Tertiary Oligocene Eocene Paleocene 70 Cretaceous Mesozoic Jurassic Triassic 230 Permian Pennsylvanian Mississippian Paleozoic Devonian Silurian Ordovician Cambrian 600 Precambrian Reference (54) RIIW RIOW R 9 W R a W R W R 6W ,•�� �t — — —� �= y •�\~ L — / 1 v < L r J n v < r / " v n � c � 4 + ' `+.\ � ` '"t Y k i y ! \ 1 `, I � 1l 1 / I � \ l � " v � v � ` " /I � � � r v � _ _ _ � P snS �'.r:' c;;:: •, •. ? \ ' \ h � I . f �4 ^ _ 1 f + i •n}1,•:'•:`•:`':`+ 'i'i:+; �r i r r . /A t ,/ c �_ - i + + v��.;;<•::•i:x \ �ldlr\tJ _ + f, 1;f:i'•iiiiri::iyr;;:'>'f:%�f�*�` _��rl I T33N /-----------_= _- f c . — - t� + gad __ '-_ -J M1 R 5 W R 4 W + + + + + I 1 + + + + ,+ t yi }+� Y % -r+ + + r = ®Ei + + t + + + + + + re �� r /\,� + + + + t`-tr\.'r`-y\', , \ ♦i + + + + + + + + +!~ - / �•RIf/� T 31 N — - �! 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QUATERNARY TERTIARY 0.0 {Ir -� -*,I I + + i MESOZOIC CRETACEOUS JURASSIC ME, UNDIFFERENTIATED SURFICIAL DEPOSITS UNDIFFERENTIATED VOLCANIC AND VOLCANICLASTIC ROCKS GRANODIORITE, DIORITE BIOTITE- HORNBLENDE GRANODIORITE, BIOTITE GRANODIORITE SCHIST, MIGMATITE, GRANITIC ROCKS r1C 7C 1CJ/C/V In L-- nnnN TRIASSIC FL ^-7 t r1 J ❑AI CA7Arl^ =j :7 R ai p- ] T 1 1 3�� N _. AL —a AMPHIBOLITES,GREENSCHIST, FOLIATED DIORITE BASALTIC METAVOLCANIC ROCKS, METABASALT AND SLATE BASALTIC TO ANDESITIC METAVOLCANICS LOCALLY INTERBEDDED WITH MARBLE THRUST FAULT TEETH ON UPTHROWN SIDE, DASHED WHERE INFE UNDIVIDED GRANITIC ROCKS V--®° DOTTED WHERE CONCEALED MAFIC INTRUSIVES INTENSE SHEARING POSSIBLE THRUST FAULT, TEETH ON UPTHROWN a' a v a a ° SIDE ® PROPOSED DAM SITES ARGILLITE AND GRAYWACKE GRANODIORITE, QUARTZ DIORITE p 4 8 SCALE IN MILES Modified from Csejtey,et ol, 1978 REGIONAL GEOLOGY FIGURE 4.1 5 - SCOPE OF GEOTECHNICAL INVESTIGATION 5.1 - Introduction The overall geotechnical investigation program for the Watana and Devil Canyon sites was designed to determine technical feasibility of the sites for development of hydroelectric facilities. The principal objectives of the 1980-81 investigation were to: - Determine the suitability of the bedrock for excavating underground structures which include penstocks, powerhouse, tailrace, and diver- sion tunnels; - Determine foundation conditions in the damsite areas. Specifically, to determine soil type and depth, thickness of weathered rock, rock permeability, groundwater regime and extent of permafrost; - Define and investigate specific geologic structural features to in- clude faults, shear and fractured zones, alteration zones, and joints; - Determine the availability of the required quantities of suitable construction materials for the dams and related facilities; and - Examine the stability of the reservoir slopes during filling and operating the reservoir. The scope developed to meet these objectives was based on: - Discussions with individuals involved in previous studies; - Detailed review of all previous data; and - Information developed during the course of this study. The engineering application of the data collected during this investi- gation was applied to the design phase of the project in Task b and is presented in the Feasibility Report (1). The details of the program for each site are discussed in Sections b and 7. 5.2 - Geologic Mapping (a) Damsites A geologic mapping program was undertaken to define the lithology and structure of the damsites and reservoirs. All the geologic data obtained in previous studies were used to supplement the data collected during the 1980-81 program. 5-1 ac�sl The Acres geologic mapping program was performed in three phases: 1980 summer, 1980/81 winter, and 1981 summer. The geologic map- ping program for each phase was initiated by aerial reconnaissance followed by a walking ground traverse. The principal objective of the 1980 program was to perform general reconnaissance mapping of the damsites and reservoirs to: - Verify existing data; - Locate potential borrow and quarry sources and refine limits and and quantity estimates; and - Identify areas that would require detailed mapping during the next two phases of the program. Data from the 1980 program were plotted on 1:6000 scale aerial photographs. The mapping was performed by a team of two geolo- gists during the period of June through August. The 1981 winter program was performed during the month of March and consisted of mapping those areas along the Susitna River and Tsusena and Cheechako Creeks that were not accessible during the warmer months. However, poor ice conditions at Devil Canyon pre- cluded mapping of several areas along the Susitna River. Particu- lar attention was directed to mapping the extent and configuration of "The Fins" and "Fingerbuster" at the Watana site. Similarly, other sheared, fractured, and altered zones were mapped along the river where access could not be gained during the summer months. Mapping consisted of identifying each outcrop and noting its size, orientation, weathering characteristics, lithology, and jointing, as well as any other significant geologic feature. All signifi- cant features were photographed. The 1981 summer program entailed detailed mapping of both dam abutments at Watana and Devil Canyon with particular attention directed at defining the extent of any unusual geologic feature denoted in the previous phases of the investigation. The extent of the detailed mapping program is shown in Figures 6.3 and 7.3. Mapping at Watana extended for approximately 3,000 feet upstream and 3,000 feet downstream from the proposed dam axis. Mapping was performed in those areas having bedrock exposure. For the most part, this was limited to the valley wails. Mapping at Devil Can- yon extended for approximately 2,000 feet upstream and 2,500 feet downstream from the proposed dam. Most of the mapping was con- fined to the gorge walls, since very little outcrop exposure exists beyond the break in slope. Mapping was performed by the "tape and Brunton" method with key areas being marked for future survey control. Mapping of the gorge walls was performed by geo- logists trained as technical climbers. All geologic data were plotted on a 1-inch to 200-foot base map. A detailed discussion of the results of the geologic mapping pro- gram is presented in Sections 6 and 7. (b) Reservoir Mapping (i) General The Watana and Devil Canyon reservoirs were geologically and geomorphically mapped to identify any geologic features and geotechnical conditions which might seriously affect the reservoir performance. Such features included buried channels and faults in the reservoir rim which may jeopar- dize the reservoir water tightness; faults which could be activated by reservoir loading; and natural slopes which may become unstable or erodible with reservoir filling or drawdown. Reservoir mapping consisted of airphoto interpretation per- formed by R&M Consultants (Appendix J) and mapping of cur- rent slope stability and permafrost (Appendix K). The scope of these programs is discussed in the following sec- tions. (ii) Airphoto Interpretation A terrain unit map was developed using a 1:24,000 airphoto base map. Field checks of specific features were performed as required. The interpretation identified 14 types of land forms or individual terrain units. These are: - bedrock - colluvium deposits - landslide - solifluction deposits - granular alluvial fan - floodplain - old terraces - ablation till - basal till - outwash - esker deposits - kame deposits - lacustrine deposits - organic deposits Results of the airphoto interpretation are contained in Appendix J. (iii) Slope Stability The potential for instability of the slopes within the Watana and Devil Canyon reservoirs after impoundment was evaluated using color aerial photographs at a scale of 1:24,000, color infrared photographs at a scale of •1:120,000, and a brief field reconnaissance. Areas of cur- rent slope instability, and the distribution of permafrost were delineated. This information, in addition to the.soil and rock conditions throughout the reservoirs, was used in identifying the potential types and zones of instability and erosion that could occur as a direct effect of the im- pounding of the reservoirs. Details of this study are pre- sented in Appendix K. 5.3 - Subsurface Investigation (a) Diamond Core Drillin Diamond core drilling was performed on the abutments of both dam - sites using a skid -mounted Longyear-34 diamond drill equipped with triple tube wireline N-size core barrel. A total of approximately 8,000 linear feet of drilling was performed at Watana and 3,600 linear feet at Devil Canyon. Seven diamond core borings were drilled at each site. All logging and supervision were by geolo- gists. All rock core was logged for lithology, core recovery, RQD, joints and fractures, shears, fracture zones and alteration zones, and other significant geologic features. A discussion of the results of the drilling program is presented in Sections 6 and 7 with Drilling Report and Summary Logs and permeability test results contained in Appendices B through E. A summary of the drilling activity for the 1980-81 field season is shown in Tables 5.1 and 5.2 with drill hole locations shown in Figures 5.1 and 5.2. (b) In -Hole Testing (i ) Permeability Testing Permeability testing was conducted in all the diamond drill holes upon completion of the core drilling. Prior to test- ing, each hole was thoroughly flushed with clear water and the drill string withdrawn. Following flushing of the hole, a packer assembly was lowered into the borehole to the desired depth. The test procedure involved inflating the packers with nitrogen to isolate a section of the bore- hole, pumping water under pressure into the test zone, and recording pressure and flow rates. Based on the flow rates, hydraulic head, hole diameter, and length of test section, the permeability of the rock in the test section was calculated. In general, the packer assembly was in- stalled to the bottom of the hole with tests being run over 16.1 foot intervals as the assembly was withdrawn. The permeability for each test section was calculated using the following formula: k = 0.0679 2LHLH I n r ACBES = a Where k = permeability, cm/sec q = constant rate of flow, gpm L = length of test section, feet H = differential head of water, feet r = radius of hole, feet In = natural logarithm A maximum test pressure equal to 1 psi per foot of vertical depth below the ground surface to the water table, plus 0.5 psi per foot of vertical depth below the water table down to the test section was used. However, in no case was the pressure allowed to exceed 200 psi. The actual gage pres- sure was adjusted to take into consideration the depth of water table. In order to obtain accurate permeability values, it was necessary that the applied pressure and flow rates be mea- sured accurately. A panel of four Fisher -Porter glass tube variable flow meters was set up as shown in Appendix D. These meters have an accuracy of 1 percent over full scale and individual ranges of 0.021-0.267 gpm, 0.095-1.19 gpm, 0.34-4.25 gpm and 0.88-11.0 gpm, The panel was set up to use any of the four meters or to bypass them altogether. Water pressure was supplied by a Royal Bean fixed -displace- ment, piston pump. Test pressure was monitored using a liquid -filled Ashcroft model 1279 pressure gage with a 0-to- 300-psi range and 2 psi divisions. The accuracy of this gage is +0.5 percent of full scale. To eliminate pressure surging in the line to the gages, a surge tank was installed and pressure snubbers were used between the pressure gage and the main line. Discussions of the results of the permeability tests are presented in Section 6.1(f) and 7.1(f). (ii) In -Hole Geophysical Logging In -hole geophysical logging was carried out in three dia- mond drill holes at the Devil Canyon site and two holes at the Watana site. BH-2 at the Watana site caved badly and was not tested. A total of 3,225 linear feet of logging was completed. The logging procedure involved lowering a geophysical probe in the hole on a wireline with the data being returned to the surface and recorded on a self-con- tained logging unit. The logs run in each hole included: temperature, caliper, resistivity, and sonic velocity. 5., ICNES The purpose for the geophysical logging was to aid in in- terpreting the subsurface conditions found at depth. Because of poor data resolution, the results of the survey have not been included in this report. Instrumentation To monitor the groundwater and permafrost conditions in the bedrock, piezometers and thermistor strings were installed in boreholes BH-3 and BH-6 at Watana (Figure 5.1); and BH-I, BH-2, and BH-4 at Devil Canyon (Figure 5.2). The piezometers used were a pneumatic type assembly manu- factured by Petur Instrument Company of Seattle, Washing- ton. The pneumatic type piezometers were selected because subfreezing temperatures were likely to be encountered in the upper portions of the holes which would cause blockage in conventional standpipe piezometers. Pneumatic type pie- zometers are also quick to install and easy to read. The thermistor strings were manufactured by Instrumentation Services in Fairbanks, Alaska. The thermistor strings were each 250 feet long with thermistor points attached at 3, 6, 9, 12, 15, 18, 21, 25, 50, 75, 100, 125, 150, 175, 200, and 250 feet. A 40-strand cable was used to connect the therm- istors to the surface, where a quick connect plug on the cable was plugged into a switch box which in turn was con- nected to a portable readout box. The system is designed to obtain two.readings at each depth so readings can be cross checked. Each thermistor point was initially cali- brated in the laboratory before installation and a computer program set up to convert readings to temperature, taking into account the correction factors for each thermistor. An accuracy of 0.05% was obtained with this equipment. The installation details of piezometers and thermistors are shown in Figures 5.3 and 5.4. 5.4 - Seismic Refraction Surveys Seismic refraction surveys were performed at both damsites during the 1980 and 1981 field seasons. This survey data was used in conjunction with borehole data, geologic mapping, and previous geophysical surveys to define: - Depth to bedrock; - Bedrock seismic velocities; - Extent of possible shear and fracture zones; - Location and configuration of relict channels, and; - Location and extent of potential borrow material. a�AEsl 5 A total of approximately 100,000 linear feet of seismic lines were per- formed for this program with the results presented in Appendices H and I. The location of the seismic lines in the damsite areas are shown in Figure 5.1 for Watana and Figure 5.2 for Devil Canyon. Discussion of the seismic lines in the borrow sites are presented in Section 6.3 and 7.2 with locations being shown on individual borrow site figures. Most of the surveys were performed using a 1,100-foot seismic line in- crement with 100 foot spacing between geophones. Shorter geophone spacing was used where terrain was rugged or overburden was shallow. Explosive charges of 1 to 2 pounds were used as the energy source and were placed at a distance of half the geophone spacing beyond the end geophones and at the middle of the lines. For shorter lines, a hammer and plate provided adequate energy. The seismic velocities were recorded on a Geometrics/Nimbus model ES-121OF 12-channel stacking seismograph. A digital/analog converter was used to display the results for data reduction. At Watana damsite, 5 traverses were run in the immediate damsite area, 10 traverses in the relict channel area, and 15 traverses in the borrow sites. At Devil Canyon, a total of four traverses were run in the immediate vicinity of the small ponds on the left abutment. Land access restric- tions prohibited any seismic work in Borrow Site G. Details of the seismic survey are given in Table 5.2. The results have been applied to the geologic and geotechnical interpretation of the site presented in Sections 6 and 7. 5.5 - Borrow Investigation Test pits and auger holes were excavated and drilled in the proposed borrow sites to determine their material properties, quantities and extent. Tables 5.4 to 5.8 provide a summary of the work in the borrow sites performed during the 1980-81 field seasons. The program initially used a platform -mounted CME-45 rig that was replaced by a CME-55 because of the difficult drilling conditions. Drilling was performed using a hollow -stem, continuous -flight auger String, having an 8-inch O.D. and a 3-1/4 inch I.D., to a maximum depth of 75 feet. Material samples were collected using a split -spoon samp- ler continuously in the upper 10 feet of the hole and then at 5-foot intervals to full depth. The sampling procedures consisted of drilling the augers down to the required sampling depth, removing the inner plug and stem, and advancing the split -spoon sampler 18 inches into the soil below the cutting head by driving it with a 140-lb hammer falling free- ly 30 inches '(Standard Penetration Test). The samples were returned to 5-7 RCBE& the surface, logged by a geologist, and prepared for transport and storage. In most cases, 4- to 6-inch long, thin brass liners were used inside the split -spoon sampler, which allowed selected samples to be capped and sealed. Following completion of the hole, the auger string was withdrawn and the hole backfilled with the drill cuttings. Test pits were excavated utilizing a JD-350 dozer equipped with a back - hoe. Average depth of the test pits ranged from 4 to 13 feet. Three trenches were excavated along the edge of the alluvial fan in Borrow Site G using the JD-350 (Figure 5.2). Bulk samples from the holes and pits were collected and sealed in air tight bags for subsequent laboratory testing. The logs for.the auger holes and test pits are presented in Appendices F and G. The properties of the borrow materials are discussed in Sec- tions 6.3 and 7.2. 5.6 - Laboratory Testin (a) Soil Representative soil samples obtained from the potential borrow sites were tested to determine their physical properties and veri- fy their field classification. Soil samples were tested to deter- mine grain -size distribution, moisture content, Atterberg limits, moisture- density relationship, permeability values, consolidation rates, and shear strength. All testing was done using ASTM or AASHTO standard procedures where applicable. The results of the testing program are summarized in Sections 6.3 and 7.2 with the laboratory data included in Appendices F and G. (b) Rock Previous rock testing at the W at ana and Devil Canyon sites was carried out by the USBR and COE. The results of this testing were incorporated into the analysis of the rock conditions where appli- cable. The rock -testing program undertaken in 1980-81 was intended to provide sufficient data to develop preliminary criteria for design of underground structure excavations and foundations. Rock sam- ples were selected for testing mainly to determine the range or rock properties to be encountered at the site. Samples selected included weathered rock, rock with discontinuities, and fresh rel- atively homogeneous rock. Samples of low -strength rock, which could not be recovered as solid core, were tested only for direct shear tests on discontinuities. All samples were tested using the appropriate ASTM standard procedures. The scope of the 1980-81 rock testing program is shown in Tables 5.9 and 5.10, with the results presented in Sections 6.1 and 7.1. ro 0•y o0o O ONNO n (D >.I . . . o 0) F-,' 0OO 0 -N nUN t err. s� @ 4- 94 co d) (D r O 01 t m CO E +- \ N 00 \ U7 m CO O m 0 00 r W \ r\\\ 00 \ N u N N zt V%O, \ co 0) C r-\Ul N \N N\ si •H v v, W n to m z n. z o_ o_ a In a In [n r- N @ co r W r r r O \ CO N \ W W W r W r \ W r \\ \ W \ O C \_\u`l \NNNM\ �N�11 r -�1,\D r CO �••• i-1 D: N L 11 � 1- o_ o_ T f � f- i] O r O O 4]3 W m W OD 00 W W 61 r! \ \ \ \ \ \ \ .N ID OD cq N 0 ao n W m ,n n n 4..-. a1 o.�H 4' x r n o rn C7 0 0 L u gcg 0c0 co m C1 R4 G r', r N (D U 0 a of m d) -q v 0 Q, r n ,O 1 L C O, r 0, O N 00 o " n n Fes- a D N � � n Nfl Q � L O 1,% co O V, 0 O 00 N .H CD C) Fl O N N 4 o -• o o ul� ,n W o O .n n +n ,n Un ,o ,a rn C 61 C] n co n co co n n u •1i Wr o� n n 4@- c�G t ) coo o FA > O W a) N c N N !n Ld Fa N ri r N n --I,O Do D E I I F F k I F x; m m m m m m m kT C Fa N u t7 d) t m E 0 o V .0 N r- LA 0 c Z) u EJ .,1 o a C N Q'A L� 0 E rl - I E 7 a-) C @ 01 . 4 @ N •A C 7 4-7 C7 O CL M[n N I[ 11 II II Fa H 4- C000.McLn a N W J co a F- m 0)--1 u1r N CD NNN } 41 , H 47 ,m 4"l N 7t r r 7 r f� tU r. row m ai N (l1 Orrr re-r E p mm m mN co W m N CY 0\ L O\i U C •i "q ro N N Z Z Z d d d F-- dT O co r m r r r p tDM aDmr\mN mN mmmrmN cr% N N M\ n D C N0\ N N M\\ � \ r 41 •H \ \\\\ r N \ N \ \ \\\ N \ H cv 6 G7 4t � N >- f r•- 'a 0 0 O r 03 m co ao m r ao CO N-i \ \ \ \ m \ \ y� -1 M O m \ tD A m CN O OD Ov N 41 ri at o m o �n o 0 0 0 4-1 ¢ C N I� f� O O r [I. u 3 r r a3 TS ¢ a3 -P a3 4-1 (0vC i-) ,C C O u1 O n O m O M O a c n �O N u1 N d Q1 O 4J u% o m VN rn r a, E e N tn ON m t` O rSv N O r N O N a C-4 •0.0 CD L7 �7 d O v C G3 O N y� In In m O\ H? D 03 r r r r r U3 ri W H N Q m 0 LrN z° x x x x z z x z m 133 m m m (D m Ra U) N R4 ¢ N G�3 a3 'H -P M E G3 O H E N 4 63 O 4�N Lf p T1 G3 N .H Q3 to 0. F+ U ••i U D p •H .rl L E f6 p •rl E I 7 r41l a3 N H 7 L U p g d C N 11 II IE G. x F- Z O] d d N x � TABLE 5.3; SUMMARY OF 1980-81 SEISMIC REFRACTION LINE DATA WCC* Line No. R&M Survey No. Line Length (feet) Number of Segments/Shots Comments 80-1 80-1 6,600 8/31 Watana Rt Abutment -Relict Channel - Extended NE by 81-13 80-2 an-2 5,500 5/19 Watana Rt Abutment -Relict Channel - Extended NE by B1-13 80-3 BD-3 2,000 4/11 Watana Abutments Upstream - 81-6 Crosses River in Middle 80-4 -- -- - Not Used 80-5 -- -- -- Not Used 80-6 80-6 1,100 2/5 Watana Rt Abutment - "The Fins" Area 80--7 80-7 2,200 2/10 Watana Rt Abutment - Upper Relict Channel Area 80-8 80-8 2,200 2/110 Quarry Source B Area - Extends SW-5 to South 80-9 80-9 1,100 1/3 Borrow Site E - Extends SW-14 to Northwest 80-10 -- - Not Used 80-11 80-11 2,200 4/13 Borrow Site E - Adjacent to Tsusena Creek 80-12 80-12 1,120 3/8 Devil Canyon Saddle Dam Area 80-13 80-13 1,120 3/0 Devil Canyon Saddle Dam Area 80-14 -- -- -- Not Used 80-15 80-15 440 1/2 Devil Canyon Saddle Dam Area 81-1 81-1 1,000 1/3 Run Over River Ice, 2.1 Miles Upstream From Watana Centerline 81--2 81-2 2,000 2/6 Run Over River Ice, 1.6 Miles Upstream from Watana Crest 81-3 81-3 500 1/2 Run Over River Ice, 1.1 Miles Upstream from Watana Crest 81-4 81-4 900 1/3 Run Over River Ice, 0.6 Mile Upstream from Watana Crest 81-5 81-5 450 1/3 Run Over River Ice, 0.5 Mile Upstream from Watana Crest 81-6 81-6 450 1/2 Run Over River Ice, 0.1 Mile Upstream from Watana Crest 81-7 01-7 3,2D0 3/9 Run Over River Ice, 4.0 Miles Downstream from Watana Crest 81-8 01-8 2,500 3/6 Run Over River Ices 5.2 Miles Downstream from Watana Crest 81-9 81-9 2,000 2/6 Run Over River Ice, 7.3 Miles Downstream from Watana Crest B1-10 81-10 2,100 2/6 Run Over River Ice, 8.2 Miles Downstream from Watana Crest 81-11 81-11 2,800 3/9 Run Over River Ice, 9.3 Miles Downstream from Watana Crest 81-12 81-12 2,000 2/7 Run Over River Ice, 10.1 Miles Downstream from Watana Crest 81-13 81--1x 3,200 3/10 Relict Channel Area - Extends 80-1 to Northwest 81-14 80-2x 3,300 3/5 Relict Channel Area - Extends a0-2 to NE - Northwest - North End Not Surveyed 01-15 BH-11 2,100 4/11 Offset to Accommodate Topography 81-16 1641 2,200 2/8 Watana Upper Relict Channel Area 81-17 -- 1,100 1/5 Watana Upper Relict Channel Area - Not Surveyed 81-18 QSB 2,200 2/10 Watana Upper Relict Channel Area - North of Quarry Source B 01-19 QSB 1,100 1/6 Watana Upper Relict Channel Area - North of Quarry Source B 81-20 SW-1x 1,600 5/11 Watana Left Abutment - Extends SW-1 East 81-21 B-12 1,850 5/19 Watana Left Abutment - Crosses 81-20 B1-22 17 1,500 3/6 Devil Canyon Left Abutment - Crosses 80-12 and BO-13 61-FL-1 to Fog Lakes 28,800 48/138 Continuous Profile - Fog Lakes Area 81-FL-48 *Profiles and time -distance plots included in (57) Location reference - Figures 5.1, 5.2, 6.38, 6.40, 6.43, and Appendices H and I 0 c O, a.] CL N 12) 0 co 0) M o 0)0� N Cl r H U Ca O Iv 03 H cp 7 -) a) U E O N N Q) N N N 'H C i!) m m m OL H 4J10 \ \ \ t ill \ \ \ G] 0 N N N U UU) U) V) U) U] (n U] V) C(0 N N N N N N N N N N m N N H m mmmmmmmaomm CD co Ga a +.� \\\\\\\\\\ \\ O co [C M Q V'1 i!1 Q V'1 V1 V'1 Vl u % \ ,7 M �Nr\•-�N\\\\\ N \N NUo r r r r r r r ri E H N L (c1 -0 m000 6] m m CD co co W m r W r m W r m 00 y)ri ill��Y NN no\n co co iG•H s�--Ul r Nr O�NrNMMN ONE in nnnnm mco mnma,rcow 4-)- 0.�] z Y L I I I I I 1 I 1, i I I 1 I I I 1 I 1 ! I k1 I E I I ©.o 3 800 m w� ••i O C)O VlOM CD Moo n0 C) � m t . m f4 C O\ t7 Vl Op OO Op o r, Q C]O l!1 La 0 3 N NNNr V1 V-O X0 WnnV, Wn�v%n D c7 L7 - O *- a o a) Q a U N O U •H n M(11, o W O\O\ r r m o0\ N n y 41 iD —C1 U1r NN zO\,nm n�DN P 7 %o M M V1 N W n r ul U1 M N n 7 N N?e% N N N N N M N1 N1 N1M N U)-4 N04 N NN NNNNNNN C'4 CD H o r N M 7 W o Q) y rN N1Vl Wn mO�rrr NM r-iL 0 0 r=0 dm d r=d I I 0 E 1 1 1 I 1 1 I I I I I I I o C) 2 3 22222 22 m====m2 co 00 Z Q¢ Q IC I[ Q¢ ¢ Q¢ Q Q¢ Q 3 3 TABLE 5.5: SUMMARY OF 1980-81 INVESTIGATION - BORROW SITE E - WATANA Number Surface Elevation Tot al Depth (ft) (Downhole) Depth to Bedrock (ft) (Downhole) Date Drilled AH-El 1424.5 25.0 7/1/80 AH-E2 1463.3 10.0 -- 7/18/80 AH-E3 1456.1 20.0 -- 7/3/80 AH-E4 1443.7 20.0 -- 7/17/80 AH-E5 1580.5 10.0 -- 6/23/80 AH-E6 1436.8 26.5 -- 7/19/80 AH-E7 1469.3 5.5 -- 7/20/80 AH-E8 1504.0 6.0 -- 7/21/60 AH-E9 1524.8 8.0 7/20/80 TP-El -- 10.0 -- 4/19/81 TP-E2 1436.6 12.0 -- 4/16/81 TP-E3 1464.2 13.0 -- 4/17/81 TP-E4 1454.9 13.0 -- 4/18/81 TP-E5 1470.1 10.0 -- 4/16/81 TP-E6 1443.4 9.0 - 4/15/81 TP-E7 1450.7 4.0 -- 4/15/81 TP-E8 1450.2 12.0 -- 4/20/81 TP-E9 1476.7 11.5 -- 4/21/81 TP-E10A 1500.7 13.0 - 4/22/81 TP-E10B 1493.7 9.5 -- 4/22/81 TP-Ell 1512.7 12.0 4/24/81 TP-E12 1534.9 11.0 -- 4/25/81 TP-E13 Not Dug -- -- TP-E14 1503.0 10.5 -- 4/26/81 TP-E15 1468.3 11.5 -- 4/28/81 TP-E16 1463.8 11.5 -- 4/30/81 TP-E17 1441.7 11.0 -- 5/1/81 TP-E18 1455.1 12.5 -- 5/2/81 TP-E19 1464.7 12.0 -- 5/2/61 TP-E20 1435.0 12.0 -- 5/3/81 TP-E21 1425.4 12.0 -- 5/3/81 AH = Auger hole TP = Test pit Reference - Figure 6.43 TABLE 5.6: SUMMARY OF 1980-81 INVESTIGATION - BORROW SITE G - DEVIL CANYON Hole Surface Total Depth (ft) Depth to- Bedrock (ft) Date Me. or Reading Number Elevation (Downhole) (Downhole) Drilled Type Dates AH-G1 982.3 23.0 -- 7/22/80 -- -- AH-G4 983.1 11.0 -- 7/22/80 -- -- AH-G9 982.0 55.0 -- 8/22/81 -- -- AH-G10 980.0 19.0 -- 8/26/81-- AH-G11 -- 31.0 -- 8/26/81 T hone AH-G12 -- 13.5 10.5 8/27/81 T to AH-G13 -- 35.0 8/28/81 T Date AH-G14 29.0 -- 8/29/81 T -- TT-G1 -- Trench -- 7/21/81 -- -- TT-G2 -- Trench -- 7/21/81 AH = Auger hole TT = Test trench T = Thermistor probe - fluid -filled standpipe Reference - Figure 7.22 TABLE 5.7: SUMMARY OF 1980-81 INVESTIGATION - BORROW SITE H - WATANA Hole Surface Tot al Depth (ft) Depth to Bedrock (ft) Date Thermistor ea ng Number Elevation (Downhole) (Downhole) Drilled Type Dates AH-HI 2127.5 26.5 23.0 7/16/01 T 1/7/82 AH-H2 1970.9 40.9 -- 7/19/01 T 1/5/82 AH-H3 2079.6 29.0 -- 7/18/81 T 1/5/82 AH-H4 2064.5 25.5 22.0 7/14/81 T -- AH-H5 2186.2 35.5 -- 7/13/81 T -- AH-H6 2181.6 43.0 -- 7/12/81 T -- AH-H7 2188.4 30.7 25.7 7/15/81 T 1/7/82 AH-HB 2693.5 35.0 -- 7/17/81 T 1/7/82 WBO-256 -- Grab -- -- - -- WBO-257 -- Grab -- -- - -- AH = Auger hole T = Theimistor probe - flUid-Filled standpipe W = Grab sample Reference - Figure 6.48 TABLE 5.8: SUMMARY OF 1980-81 INVESTIGATION - BORROW SITES I & J - WATANA Test Pit Number Surface Elevation Tot al Depth (ft) (Downhole) Daptho Bedrock (Ft) (Downhole) Date Drilled TP-R1 -- 4.5 -- 9/17/81 TP-R2 -- 5.0 -- 9/17/81 TP-R3 -- 5.5 -- 9/17/81 TP-R4 -- 4.5 -- 9/17/81 TP-R5 -- 4,5 -- 9/18/81 TP-R6 -- 5.0 -- 9/18/81 TP-R7 -- 4.0 -- 9/18/81 TP-RB -- 2.5 -- 9/17/81 TP-R9 -- 3.5 -- 9/18/81 TP-R10 -- 5.5 -- 9118181 TP-R11 4.0 -- 9/18/81 TP-R12 -- 5.0 -- 9/19/81 TP-R13 -- 6.0 -- 9119181 TP-R14 -- 6.0 9/19/81 TP-R15 -- 6.0 -- 9/20/81 TP-R16 -- 5.5 -- 9/20/81 TP-R17 -- 4.5 -- 9/20/81 TP-R1B -- 5.0 -- 9/20/81 TP-R19 -- 4.0 -- 9/21/81 TP-R20 -- 5.0 -- 9/21/81 TP-R21 -- 4.5 -- 9/21/81 TP-R22 -- 5.0 -- 9/21/81 W80-302 -- Grab -- 1980 TP = Teat pit W = Grab sample Reference - Figures 6.51 and 6.52 TABLE 5.9- SUMMARY OF ROCK TESTS - WATANA Type of Test o. of Tests By Acres Standard No. of Tests by Others Unconfined Uniaxiel Compression 29 ASTM D2938-71a -- Unconfined Uniaxiel Compression with Stress/Strain Plot 4 ASTM D314B 6 Direct Shear 3 -- -- Indirect Tension 11 ASTM C496 -- Point Load Teat 303 -- -- Specific Gravity 44 ASTM C97-47 (1970) 5 Dynamic Modulus 2 ASTM D2845-69 (1976) -- TABLE 5.10: SUMMARY OF RUCK TESTS - DEVIL CANYON Type of Test o. of Tests By Acres Standard No. of Tests Others Direct Shear 6 __by Indirect Tension B ASTM C496 �- Point Load Test 338 -- -- Specific Gravity 40 ASTM C97-47 (1970) 6 Dynamic Modulus 3 ASTM D2B45-69 (1970) B Unconfined Unaxial Compression 26 ASTM D293B-71a -- Unconfined Unaxial Compression with Stress/Strain Plot 6 ASTM D3148 7 RIIW RIOW R 9 W R a W R W R 6W ,•�� �t — — —� �= y •�\~ L — / 1 v < L r J n v < r / " v n � c � 4 + ' `+.\ � ` '"t Y k i y ! \ 1 `, I � 1l 1 / I � \ l � " v � v � ` " /I � � � r v � _ _ _ � P snS �'.r:' c;;:: •, •. ? \ ' \ h � I . f �4 ^ _ 1 f + i •n}1,•:'•:`•:`':`+ 'i'i:+; �r i r r . /A t ,/ c �_ - i + + v��.;;<•::•i:x \ �ldlr\tJ _ + f, 1;f:i'•iiiiri::iyr;;:'>'f:%�f�*�` _��rl I T33N /-----------_= _- f c . — - t� + gad __ '-_ -J M1 R 5 W R 4 W + + + + + I 1 + + + + ,+ t yi }+� Y % -r+ + + r = ®Ei + + t + + + + + + re �� r /\,� + + + + t`-tr\.'r`-y\', , \ ♦i + + + + + + + + +!~ - / �•RIf/� T 31 N — - �! '� -` t`�y_-s/_ ,! i`_/ _/ti\ �' + -- r.•.;'..-,,,��� _ e / _ -- -_ __- __-_ - _ --_-_-___ _ _-_- - _ _—_ __ _--� 1 !' 1 / r ! `!, 1 r � ♦ 1 t �---���frrrl��� r • � ! �If � � , `�•..+f a a ---------- ---,\i�f�/J ! �� 1'/� 5 f;;:•; R/ j ? II • _-__—_-____— - _,?3:� 'ems _ {\�� i C•::::ri{J'-/1 .y- p,{ • 10 - - - - - — ------- —— — — ----- u �'•L4`L' -- --4' J 1 �'l G'('t L v 32 N LEGEND O T 31 N T 30 N R 2E / kn)w_^ rR7\7 cAAAnnnnnn nnnnnn nnnnnnnnnn nnnnnn nnn .nnn nnnnnnnn nt ,nnn nnnn n n nnnnnnnn nnn n\ nnnn nnnnn nnn nnnnnnn nnnn n/j nnnnn nnnn nnnnnn nnnnnn nnnnn nA .nnnnn nnn nnnnnnn nnnnnn nnnnn AA ••p n nnnnnnnnnnnn nnnnnn nnnnn n n nnnnnnnnnnnn nnnnn nnnnn n AA A A A A 7 T_X7\1yC nnnnnnnnnnnn nn n nnnn A) n nnnnnnnnnnn nnnnnnnnnnnn n nnnn nnnn n) n nnnnnnnnnnnn nnnnnnnnnnnn n nnnnnn nn n) n nnnnnnn nnnn nnnnnnnnnnnn n nnnnnnnnnn nn, n nnnnnnn nnnn n nnnnnnnnnn nn nnnnnnnnn; 1. nnnnnnn -A S� �n n nnnnnnnnn ?_ \Annnn r n '4 nn 14 n1 nnnn n nnnnn, - ��.n n \ AAAAA �' ynnn,✓ I —rc'n n /n n n n ,(AAy' Innnn r'\ �61' i n n m. b1 �t i nnn AAA nnnn Pil R 3 E `-nnn % A n ram- Y°� RIVE I? QUATERNARY TERTIARY 0.0 {Ir -� -*,I I + + i MESOZOIC CRETACEOUS JURASSIC ME, UNDIFFERENTIATED SURFICIAL DEPOSITS UNDIFFERENTIATED VOLCANIC AND VOLCANICLASTIC ROCKS GRANODIORITE, DIORITE BIOTITE- HORNBLENDE GRANODIORITE, BIOTITE GRANODIORITE SCHIST, MIGMATITE, GRANITIC ROCKS r1C 7C 1CJ/C/V In L-- nnnN TRIASSIC FL ^-7 t r1 J ❑AI CA7Arl^ =j :7 R ai p- ] T 1 1 3�� N _. AL —a AMPHIBOLITES,GREENSCHIST, FOLIATED DIORITE BASALTIC METAVOLCANIC ROCKS, METABASALT AND SLATE BASALTIC TO ANDESITIC METAVOLCANICS LOCALLY INTERBEDDED WITH MARBLE THRUST FAULT TEETH ON UPTHROWN SIDE, DASHED WHERE INFE UNDIVIDED GRANITIC ROCKS V--®° DOTTED WHERE CONCEALED MAFIC INTRUSIVES INTENSE SHEARING POSSIBLE THRUST FAULT, TEETH ON UPTHROWN a' a v a a ° SIDE ® PROPOSED DAM SITES ARGILLITE AND GRAYWACKE GRANODIORITE, QUARTZ DIORITE p 4 8 SCALE IN MILES Modified from Csejtey,et ol, 1978 REGIONAL GEOLOGY FIGURE 4.1 31 Pill Lo w 1 A ---------- -- --- e— DETAILED DAMS ITE SEISMIC LINE AND BORING EXPLORATION MAP SHOWN ON FIGURE 5.1 b ------------- DETAILED BORROW SITE D EXPLORATION MAP SHOWN ON FIGURE 6.40� REFERENCE: I"=200' COE,1978 WATANA DAMSITE TOPOGRAPHY, SHEET I THROUGH 26 LEGEND BOREHOLES AND TEST PITS: 197B,COE ROTARY DRILL BORING GEOPHYSICAL SURVEYS: SEISMIC REFRACTION SURVEY END OR TURNING POINT DI'A- C 1975, DAMES a MOORE SVI-2 197B,SHANNON Ek WILSON . ..... qL01-5 1900-BI.WOODWARD-CLYDE CONSULTANTS NOTES Q, L DETAILED EXPLORATION MAP OF DAMSITE ON FIGURE 5.1b 21 BORROW SITE D TEST PITS AND AUGER HOLES, AS WELL AS SEISMIC LINES, SHOWN ON FIGURE 6.40. 3. DETAILED SECTION ON DM -A a B ON FIGURE 6.31, 4. RIVER ALLUVIUM TEST PITS SHOWN ON FIGURES 6.61 AND 6,62, 5 RELICT CHANNEL AREA MAP SHOWN ON FIGURE 6.35. 6. CONTOUR INTERVAL 100', ENLARGED AND TRACED FROM REFERENCED BASF, MAP. 7. D 5 M SEISMIC LINE LOCATIONS CORRECTED PER COE 6;1? SURVEY AND REFERENCED BASE MAPS. 8. S a W SEISMIC LINE LOCATIONS CORRECTED FROM ORIGINAL FIELD BOOKS AND SaW, 1978. 9, LINE DM-13 CONTINUED I LOCO FEET NORTH OF TURNING POINT SHOWN, 10. COE EXPLORATION LOGS AND S a W SEISMIC PROFILES AS REFERENCED. 11, WCC SEISMIC REFRACTION DATA SHOWN IN APPENDICES H AND I. 12,NORTKING GRID LINES ARE IN ERROR BY APPROXIMATELY 50 FEET, NORTH, FROM STATION N 3, 232, 000 TO N 3, 234, 000. WATANA CONTINJES OFF PACE SEE NOTE 9 DAMSITE VIC1 NITY- EXPLORATION MAP 0 1000 2000 FEET SCALE FIGURE 5.1a N 3,227,0C%0 Z TP R-8 m 3,�aspw CONTINUES OFF PAGE SEE NOTE 8 LEGEND BOREHOLES AND TEST PITS1 H-1 1978,COE )DIAMOND CORE BORING, HORIZONTAL PROJECTIONS AS SHOWN BH-e 198D-81.AAI� NM TPR 11 19BI,AAI BACKHOE TEST PIT GEOPHYSICAL SURVEYS: SW-1 SEISMIC REFRACTION SURVEY END OR TURNING POINT ------ DM-G 1975, DAMES &MOORE DH-24 10 ------ SW -I 197B, SH ANNON Ek WI LSON SL 60-1 1980-81,WOODWARO-CLYOE CONSULTANTS S B I - 20 swz! ---------- DH-12 - ------- ...... NOTES 1. GEOLOGIC SECTIONS SHOWING EXPLORATION DETAILS ON FIGURES 6.4 THROUGH G.S. OVERALL SITE EXPLORATION PLAN SHOWN ON FIGURE 5.1a. 2.EXTENSIONS OF EXPLORATIONS TO NORTH AND 3.CONTOUR INTERVAL 50� TRACED FROM REFERENCED BASE MAP. 4.S aW SEISMIC LINE LOCATIONS CORRECTED FROM ORIGINAL b FIELD BOOKS AND S Eh W,19TS. OH 5.FOG LAKES SEISMIC LINE (sLBI-FLITHRU48) LIES JUST OFF - ------ TOP OF PAGE (SEE APPENDIX I -------------- G.CCE EXPLORATION LOGS AND 5 BMW SEISMIC PROFILES AS 0DH-5 REFERENCED. FLOW D L DH 4 . ..... Z A A I DRILL LOGS A NO SELECTED COE BORING R ELOGS SHOWN H-3 •IN APPENMX B H B.WCC SEISMIC REFRACTION LINES SHOWN IN APPENDICES H AND I. Si"i1A A TFIR-11 ml-6. Z ------- - -- vlol) pCr ... ... ....... ---- A op :5� TINUES OFF CON -------- -- ------ PACE SCE NOTE 2 ell ---- ------ 8H 3 H-4 f 0 ZOO 400 FEET SCALE REFERENCE: BASE MAP FROM COE,1978-1"-200' WATANA TOPOGRAPHY, SHEET 8 0, 13 OF 26,COORDINATES IN FEETALASKA 2 00 3 STATE PLANE (ZONE 4) COE, 1978 s aw.1978 WOO, 1980-81 WATANA EXPLORATION MAP CONTINUES OFF PAGE SFF NOTE 2 FIGURE 5.1 b of 3,2zI, N3,222,OIJC h w2 m Yd 3,z24,0io REFERENCE: BASE MAP FROM RRM,1961--1"-200' DEVIL CANYON TOPOGRAPHY USBR, 1960 S fi W,1978 COE,1978 COORDINATES IN FEET, ALASKA STATE PLANE ( ZONE 4) DEVIL CANYON EXPLORATION MAP LEGEND SOREHOLES AND TEST PITS: I DH-14 1958, USER DIAMOND CORE . BORING,HORIZONTAL 2H-I 1980 81,AAI PROJECTIONS AS SHOWN m AH-C€ 1960-81,AAI AUGER BORING TTK-17 1956, USER DOZER TRENCH TP K-93 HAND DUG TEST PIT S-3 BLASTED ROCK SHELF 00 TT -GI 1981,AAI DOZER TRENCH GEOPHYSICAL SURVEYS: n SW-15 SEISMIC REFRACTION SURVEY END OR TURNING POINT I SW-15 1970, SHANNON 8 WILSON SL©D-13 ea 1980-BI, WOODWARD-CLYDE CONSULTANTS NOTES I. GEOLOGIC SECTIONS SHOWING EXPLORATION DETAILS SHOWN ON FIGURES 74 THROUGH 7.10. 2.CONTOUR INTERVAL 50; TRACED FROM REFERENCED BASE MAP. 3.USBR EXPLORATIONS TRANSFERRED FROM USBR 1960 BY COORDINATES AND FROM USGS 1958, 4.S e, W SEISMIC LINE LOCATIONS CORRECTED FROM ORIGINAL FIELD BOOKS AND S d W, 1978. S.USBR,COE EXPLORATION LOGS AND SEISMIC PROFILES AS REFERENCED. 01 G.AAI AND SELECTED USBR BORING LOGS SHOWN IN 0 APPENDIX C, 7.WCC SEISMIC REFRACTION LINES SHOWN IN APPENDICES H AND T. 0 200 400 FEET SCALE FIGURE 5.2 1:1111, TO READOUT LEGEND OVERBURDEN ///-//iQVII ROCK yII� 0.75 -INCH I.D. THREADED JOINT PVC GROUT TUBE THERMISTOR POINTS HOLES DRILLED IN PVC GROUT TUBE TO ALLOW GROUT TO ESCAPE PNEUMATIC - PIEZOMETER TIP END PLUG GROUNC S PACKER INFLATION LINE AND PIEZOMETER READOUT TUBES ---NO--BOREHOLE (2.98INCH DIAM.) PERMAFROST CEMENT GROUT EPDXY -FILLED NX--SIZE PACKER SLOTTED PVC PIPE TO PROTECT PIEZOMETER BOREHOLE INSTRUMENTATION WATANA : BH-6 AND BH-3 DEVIL CANYON: BH--2 PREPARED BY R &F1, CONSULTANTS, INC. (NOT TO SCALE) FIGURE 5.3 RCNfS LEGEND OVERBURDEN ROCK ri�lr�l�lk� NOTE TWO PIEZOMETER/PACKER INSTALLATIONS WHERE MADE IN BH-I 20-FOOT SLOTTED - SECTION. THREE ROWS 0.010-INCH SLOTS 0.5-INCH I.D. PVC - GROUT VENT TUBE FOAM SEAL END - PLUG 0.5- INCH I.D. PVC GROUT TUBE 2-INCH I.D. THREADED JOINT PVC CASING {I7M a, ri, i NQ-BOREHOLE (2.98 INCH DIAM.) THERMISTOR POINTS PACKER INFLATION LINE ANC PIEZOMETER REAE- OUT TUBES PERMAFROST CEMENT GROUT '--NX--SIZE SLIMLINE PACKER -PNEUMATIC PIEZOMETER TIP FILTER SAND GROUT TUBE 5-FOOT SLOTTED SECTION. THREE ROWS OJO-tNCH SLOTS TYPICAL BOREHOLE INSTRUMENTATION DEVIL CANYON: BH-1 AND BH-4 (NOT TO SCALE) RCRIS PREPARED BY R a M CONSULTANTS, INC. FIGURE 5.4 6 RESULTS OF GEOTECHNICAL INVESTIGATIONS - WATANA The results of the geotechnical studies performed at the Watana site are presented in this section. The three principal subsections are: - Subsection 6.1: Watana Damsite; - Subsection 6.2; Relict Channels; and - Subsection 6.3: Borrow & Quarry Material. Map locations presented in this section are shown on the Watana Index Map - Figure 6.1. 6.1 - Watana Damsite (a) Overburden Conditions (i) General A top -of -bedrock and surficial geologic map for the damsite area is shown on Figure 6.2. Determination of these over- burden thicknesses and material types at the site has been based on geological mapping, seismic refraction surveys, drilling, and test pits. Geologic profiles depicting sub- surface stratigraphy in the main dam area and borrow sites are presented in later sections. Data used in developing these figures are provided in Appendices B, F, H, and I While Table 6.1 provides the correlation of seismic velo- cities with soil and rock types used for this study. (ii) Damsite Within the limits of the damsite, three distinct zones of overburden can be delineated at the site. These are; (a) top of sloppe (elevation ap roximately 2200) to approximate Elevation 1950 to 1900; (b� Elevation 1900 to river level; and (c) riverbed. The upper areas of the abutments near the top of slope con- sist of deposits of till, alluvium, and talus. On the north abutment, the alluvium is significantly intermixed With talus material. The thickness of this cover may reach 50 to 60 feet. On the south abutment, the average overbur- den depth is estimated at 20 feet with isolated zones of apparent channel. fill material reaching 70 feet or more, as shown by seismic line SL81-20 and DH-25 (Figure 6.2). Below Elevation 1900 to 1950 where the valley changes from a "U" shape to a "V" shape, the overburden becomes thinner and more varied, ranging from probable maximums of 40 .feet thick at the river edge (where there are talus and minor s , RCNES avalanche deposits) to zero along the numerous rock cliffs. Most of the material is rock derived from the cliffs with occasional remnants of silty sand and gravel river terrace deposits. Some larger, well-rounded boulders occur at the lower elevations. The average abutment overburden thick- ness in this zone is estimated to be 10 feet of alluvium and loose talus materials. Cobbles and gravels occur from flood elevation (about 1470 feet) down to the river. Boreholes and seismic lines in the river shove a relatively consistent deposit of river al- luvium composed of gravel, cobbles, and boulders with a sand matrix interspersed. The maximum depth of river allu- vium in the main dam area is estimated not to exceed 90 feet. A recent seismic refraction survey suggests that there are bedrock shallows near the proposed upstream cofferdam site (Appendix I). This interpretation is questionable because of the poor resolution of the seismic data. A more reason- able interpretation would be either the existence of frozen material or the presence of very densely compacted talus material that has been eroded from the adjacent "The Fins" structure (Section 6.1[cl). However, further work will be required in this area to confirm these velocities. ( i i i ) Emergency Spi 1 lwM The upper portion of the proposed emergency spillway is founded in an area of shallow overburden, whereas the west- northwest extension of the spillway that extends downslope off the flank of the pluton is in an area of deeper over- burden. The estimated depth to rock in this area is shown in Figure 6.2. (iv) Camp Areas (v) The proposed construction camp an is northwest of the damsite in an that consists primarily of sands spersed boulders. Bedrock depths 100 feet throughout the area. A of the geology and overburden of t Section 6.2. Access Roads d permanent village site area of deep overburden and gravels with inter - are expected to exceed more complete discussion his area is presented in Construction of access roads to the site will encounter areas of very deep overburden. Access and haul roads out- side the damsite area will, to some degree, be routed along gravel terraces, but in many areas will cross shallow, RCNf3 6 boggy, and swampy areas and zones of till, clays, and silts. Further detailed investigations will be required in subsequent phases of study to accurately determine soil and foundation conditions along proposed access routes. (b) Lithology (i) Introduction The Watana site is located on the western side of a Ter- tiary age (Table 4.1) igneous plutonic body which consists primarily of diorite and quartz diorite (Section 4). This pluton is bounded in the site area by andesitic volcanic flows and volcaniclastic sedimentary rocks. These rocks have not been assigned formational names, but rather have been given lithologic names for mapping and correlation purposes. The lithology and structure at the Watana site are shown on a geologic map, Figure 6.3, and five geologic sections, W-1 through W-5 (Figures 6.4 to 6.8). The geology shown in these figures is based on field map- ping, and borehole and seismic refraction data (Section 5). Where possible, mapped surface structures were correlated with subsurface drilling and seismic refraction data. How- ever, the limited rock exposure and the widely spaced sub- surface exploration data in the damsite frequently required extrapolation of geologic contacts and structural features over great distance. Therefore, future investigations will be necessary to confirm the location and continuance of those features shown in the figures. For simplicity, borehole information shown on Figures 6.4 to 6.8 is limited to features five feet or greater in thickness. More detailed information is contained in Appendices B, D, H, and I. The following subsections address the site lithology. (ii) Plutonic Rocks At the Watana site, the pluton is nearly continuously ex- posed in large outcrops along the south bank between Ele- vations 1650 and 1900. On the north bank, outcrops are generally smaller and less frequent (Figure 6.2). The rocks of the pluton are primarily diorite and quartz dio- rite with lesser amounts of granodiorite. These varied lithologies are probably the result of chemical variations within the parent magma, primarily increasing silica con- tent from diorite to granodiorite. The rock types are s-, ACNlS1 observed in both outcrop and boreholes to grade from one to the other. A 20-foot wide gradational contact between the diorite and quartz diorite is exposed at river level on the south bank approximately 1,000 feet upstream from the dam centerline. A similar gradational contact is found in boreholes BH-6 and BH-8 (Appendix B) over 0.3 foot at Ele- vation 1594 and 3.8 feet at Elevation 1708, respectively. Since no mappable pattern was found to differentiate these three rock types, they have been combined on the geologic map and sections under the general name of diorite. The diorite here is described as a crystalline igneous rock which is predominantly medium greenish gray but varies to light gray and light to medium greenish gray in the grano- diorite and quartz diorite phases, respectively. The tex- ture is massive with no planar structures. Grain size var- ies from fine (less than 1mm) to medium (1-5mm) but is usually medium. The diorite is generally composed of 60 to 80 percent feldspar, 0 to 10 percent quartz, and 20 to 30 percent mafics. Quartz content of the quartz diorite ranges up to 20 per- cent but is usually 10 to 15 percent. The feldspar con- sists primarily of medium grained, euhedral plagioclase with minor amounts of fine grained anhedral orthoclase. In the granodiorite, orthoclase content is about 10 percent. Quartz, when present, is fine grained and intergrown be- tween the feldspar crystals. Mafic minerals, consisting of biotite and hornblende, are generally fine grained. The hornblende is often partially chloritized. Trace amounts of sulphides and carbonate also occur within the diorite. Inclusions of argillite have been observed in the diorite in "The Fins" area (Figure 6.3). The diorite is generally fresh and hard to very hard. The rock is slightly weathered along the joint surfaces at a depths of about 50 to 80 feet (Section 6.1Ec]). There is generally a very thin (less than 2 inches) weathering rind on most outcrops. The pluton has been intruded by both mafic and felsic dikes which are discussed below. Zones of hydrothermal alteration occur within the diorite. The alteration has caused the chemical breakdown of the feldspars and mafic minerals. The feldspars have altered to kaolinite clay and the mafics altered to chlorite. Hydrothermal alteration is discussed in detail in Section 6.1(c). iACNEs s (iii) Andesite Por h r The name andesite porphyry is used for a varied group of apparently related extrusive rock types (46). The andesite porphyry occurs along the western side of the diorite plu- ton and is exposed in outcrops on both sides of the Susitna River (Figure 6.3). On the south bank, outcrops occur across from the "Fingerbuster" and at approximate Elevation 1750, immediately downstream from the dam centerline. And- esite porphyry was drilled in boreholes BH-4 (Figure 6.4), BH-8 (Figure 6.5), and BH-2 (Figure 6.7) to depths of 96.0, 43.0 and 103.0 feet, respectively. Borehole DH-28 bottomed at 125 feet in the porphyry (Figure 6:8). Andesite por- phyry dikes are also found interspersed in the diorite. On the north bank, the andesite is exposed at river level in the "Fingerbuster" area and in scattered outcrops to about Elevation 2350. The andesite porphyry is a light to medium dark greenish gray volcanic rock similar in composition to the diorite pluton. The color becomes lighter with increasing amounts of lithic inclusions. The groundmass is aphanitic (grains visible only with the aid of a microscope) with generally 10 to 30 percent of fine to medium grained plagioclase feldspar phenocrysts. Lithic inclusions are found through- out the andesite porphyry but are most concentrated near the contact with the diorite. Concentrations of subrounded to subangular fragments, up to 6 inches in diameter, of quartz diorite, argillite and volcanic rocks were found above the diorite contact in BH-8 (Appendix B). The ande- site porphyry is fresh to slightly weathered and hard. Hydrothermal alteration is not common in the andesite por- phyry. The andesite porphyry also contains layers or zones of dacite and latite and basalt. The latite occurs in the "Fingerbuster" area (47) and the dacite in Quarry A. The basalt occurs in the area of the volcaniclastic sediments downstream from the "Fingerbuster." These varied rock types appear to be irregular and discon- tinuous in the site area and could not be mapped over large areas. Therefore, the term andesite porphyry has been used as a general term for all of these volcanic units. Outcrops on the south bank near the diorite contact contain from 30 to 50 percent lithic fragments in an andesite mat- rix. Flow structures are visible in outcrops and boreholes in the areas of abundant lithic fragments. On the south o-5 ACflIS bank, about 350 feet northeast of DH-28, the flow structure strikes east -west and dips 200 to the south. In the "Fing- erbuster" area, flow structures strike northwest -southeast and dip 15' to the west. Figure 6.9 is a photograph of the andesite porphyry in the "Fingerbuster" area which shows numerous lithic inclusions, as well as flow structure line- ation. A sequence of volcaniclastic rocks (46) composed of tuf- faceous sandstones and siltstones are exposed 2,500 feet downstream of the contact between the andesite porphyry and the diorite. The siltstones are medium gray, fine grained while the sandstone has a buff colored ground mass with grains of feldspar, quartz and argillite. Bedding of these units strike nearly north -south with dips generally less than 30' to the west. The rock is slightly weathered and iron oxide stained. The relationship between the volcani- clastic rocks and the andesite porphyry is not clearly defined because of outcrop exposure. (iv) Contact Between Andesite Porphyry and Diorite The contact between the andesite porphyry and the under- lying diorite has been mapped immediately downstream from the proposed dam centerline, extending in a general north- westerly direction across the left abutment and northerly across the right abutment (Figure 6.3). On the south bank it is intersected in BH-8 and BH-12 and exposed in one out- crop west of the dam centerline at about Elevation 1750. At this point, between 400 to 800 feet northeast of DH-28, the diorite is generally fresh to slightly weathered and unfractured. The andesite porphyry is slightly to moder- ately weathered and fractured up to 10 to 15 feet above the contact. Figure 6.10 is a photograph showing the closely to very closely spaced joints in the andesite porphyry immediately above the diorite contact. Where the contact is exposed on the south bank, minor shearing, less than 1 inch wide, occurs between the ande- site porphyry and the diorite. The contact in this area strikes nearly east -west with a dip. of 450 to the south. In BH-8, the andesite porphyry/diorite contact is found at a depth of 43.0 feet. From 38.4 to 43 feet, thin layers of andesite porphyry are moderately to severely weathered with layers of silty sand. Core loss in this zone was 1.1 feet with only 50 percent drill water return. The contact in BH-12 was intersected at a depth of 63.7 feet. Unlike BH-8, the andesite above the contact (from 54.8 to 63.7 feet) is fresh to moderately weathered with generally closely to moderately closely spaced joints. The contact occurs over a 3-inch-wide zone where the andesite porphyry interfingers with the diorite. The diorite is fresh below the contact. Core recovery was generally 100 percent through the contact zone with variable RQDs. Permeabilities are on the order of 10-5 cm/sec. On the north bank, the contact is not exposed but was in- tersected in BH-2 and BH-4. In BH-4, very closely spaced joints with silt and clay coating occur in the andesite porphyry from 94.1 feet to the contact at 96 feet. As in BH-12, very thin fingers of andesite porphyry penetrate the diorite at the contact. The diorite below the contact is slightly weathered with iron oxide staining in the upper 0.5 feet. RQDs are quite low, ranging from 0 to 51 percent in the upper 15 feet of the diorite. Permeabilities, how- ever, are low at about 10-6 cm/sec. The contact from river level (Elevation 1450) to about Elevation 2000 in this area is coincident with a major shear zone ("Finger - buster") (Section 6.1[c]). This zone, which was drilled in BH-2, showed low RQDs and core loss. This poor quality rock is the result of post -intrusion shearing of the "Fin- gerbuster" and not necessarily representative of the con- tact. Above Elevation 2000, the contact is assumed to dip moderately to the northwest. (v) Dikes The diorite pluton has been intruded by both mafic and fel- sic dikes. No dikes were found in the andesite porphyry. Because of their small size, the dikes could not be deline- ated as mappable units. Felsic dikes are found in outcrops and in all boreholes. Felsic dikes are light gray and aphanitic to medium grain- ed, but generally fine grained. The felsic dikes are com- posed primarily of feldspar (plagioclase and orthoclase) with up to 30 percent quartz and less than 10 percent maf- ics. Contacts with the diorite are tight and "welded". The felsic dikes are hard, fresh, and unfractured. Dike widths are up to 6 feet but generally less than 0.5 feet. Felsic dikes have been found offset up to several inches by shears and healed shears in outcrop and in boreholes (BH-3 at 702.7 and 801.3 feet). Figure 6.11 shows a 7-inch wide felsic dike offset along a healed shear. The healed shear is tight and hard. Mafic dikes are less common at the site than the felsic dikes. They are rarely seen in outcrop and only found in boreholes BH-1, BH-2, BH-8, and BH-12. The mafic dikes, consisting of andesite or diorite, are dark green to dark green gray. Grain size is aphanitic to very fine, with fine to medium grained plagioclase phenocrysts (BH-2, Appendix B). The mafic dikes are hard and fresh with tight contacts. Dike widths are generally less than 1 foot, although in BH-2, an andesite dike was drilled from 245.E to 277.8 feet. Diorite inclusions were also found in this dike. A possible mafic dike was mapped on the south bank at river level upstream from the centerline. This dike is approximately 5 feet wide and consists of fine grained dio- rite. The dike is very closely to closely jointed and occurs in a talus -filled gully. The trend of the dike is northwest -southeast parallel to a major joint set. As with the felsic dike, the mafic dikes could not be mapped over an extensive area. A large mafic dike; 350 to 400 feet wide, has intruded into the diorite upstream from the proposed diversion tunnel in- take portal. Outcrops occur in the "The Fins" on the north bank and in Quarry L on the south bank (Figures 6.3). The dike is porphyritic with an aphanitic to fine grained ground mass. Medium grained phenocrysts, consisting pri- marily of plagioclase feldspar and lesser amounts of horn- blende, comprise up to 10 percent of the rock in "The Fins" and 20 to 30 percent on the south bank. The bedrock in this area has been termed a diorite porphyry. The rock is fresh hard and generally massive with rare occurrences of compositional layering or possible flow structure. Inclu- sions in this unit consist of rounded diorite and tabular argillite fragments from 1 to 6 inches long. Contacts with the inclusions are sharp and tight. The diorite porphyry becomes less porphyritic and more aphanitic near the contacts with the diorite pluton. The western contact in "The Fins" is coincident with a 20-foot- wide shear/alteration zone (see Section 6.1[c3). The eas- tern contact is not exposed. (c) Structural Geology (i) Introduction This section discusses the structural geology at the Watana site and its relation to proposed site facilities. This section is presented in three subsections: joints; shears, fracture zones, and alteration zones; and significant geo- logic features. (ii) Joints Joint data were recorded at all outcrops, as well as at nine joint stations (WJ-1 through WJ-9) which were selected for detailed joint measurements (Figure 6.12). Joint sta- tions were chosen at representative areas having good RCNES 6 A three-dimensional exposure of major structures and in the major rock types: diorite, andesite porphyry, and diorite porphyry. At outcrop and joint stations, the orientations of major and minor joint sets were recorded, as well as the condition of the joint surfaces, spacing, and any minerali- zation or coating. At stations WJ-1 through WJ-3, only 60 to 86 joint readings were taken because of limited exposure, while one hundred joints each were recorded at each of the other six sta- tions. For each station, joint measurements were plotted on the lower hemisphere of a Schmidt equal-area stereonet and contoured at 1, 3, 5, 7, 10, and 15 percent. An example illustrating the plotting method (5) is presented on Figure 6.12. In addition to the joint station plots, composite joint plots were constructed from both joint station and outcrop data. The site was divided into four quadrants. A compos- ite plot for each quadrant is shown in Figure 6.13. Two major and two minor joint sets were mapped at the Watana site and are identified on the composite and joint station plots. Sets I and II are major sets which occur th oughout the site area. Sets III and IV are minor sets which are generally less prominent but may be locally strong. Each joint set is discussed below, while Table 6.2 is, a summary of joint set orientations, dips, spacings, surface conditions, and structural relations. The joint sets are common to all rock types at the damsite. This discussion is based on mapped surface jointing. Because the orientations of joints and fractures in the boreholes were not determined, it is not possible to corre- late between joints in outcrop and those encountered at depth. Joints in boreholes are discussed separately. Joint Set I is the most prominent set at Watana. The aver- age orientation is 320' in the four quadrants (Figure 6.13). Dips average 80' northeast in the northeast and southeast quadrants and vertical in the northwest and southwest quadrants. Joint surfaces are planar and smooth to rough and have an average spacing of 2 feet. Joint sur- faces in the diorite porphyry in "The Fins" are pitted and rough where feldspar and hornblende phenocrysts have weathered out. Minor carbonate deposits were found on Set I surfaces at joint stations WJ-4, WJ-6, and WJ-7 (Figure 6.12). The joints are continuous and generally tight. Open joints are found at the surface in fracture zones and shears. Set I parallels most major shears, fracture zones, and alteration zones found at the site. 6., RCRa A subsidiary Joint Set (Ib) to Set I was found in the area downstream of the dam centerline at joint station WJ-7. This subset trends from 290' to 300' with an average dip of 75' northeast. This subset is also strongly developed at joint stations WJ-1, WJ-2, and WJ-9 (WJ-2 is in the area of the diversion tunnel outlet). The subset in the northwest and southwest quadrants (downstream from WJ-4) is parallel to the trend of the shears in geologic features GF 7A, GF 7B, and GF 7C (see Significant Geologic Features) (Figure 6.3). This trend is also parallel to the Susitna river between the dam centerline and diversion tunnel out- let. Joint Set II is northeast -trending, ranging in strike from 045' to 080' with an average trend of 060' across the site. Most dips are steep from 800 southeast to 80' northwest. Set II is best developed in the northeast and southeast quadrants where the trend averages 050' with a preferred dip to the northwest. At stations WJ-3 and WJ-5, near the diversion tunnel entrance, Set II is more strongly develop- ed than Set I, while at joint station WJ-6 in the diorite porphyry approximately 200 feet upstream from WJ-3, no Set 11 Joints were found. It is likely that the face of the outcrop at this station was parallel to Set II joints resulting in no exposure of that set. In the northwest and southwest quadrants, Set II trends more to the east with an average strike of 0650 and dips vertically. Set II joints are generally planar with smooth to rough surfaces. Joint spacings range from 1 inch to 5 feet, averaging 2 feet. Set II is generally continuous and tight. Open joints were found on the south bank at WJ-1 and at several other out- crops. No shears or alteration zones were found associated with Joint Set II. Joint Set III is generally north -south trending, ranging in strike between 340' and 030' with variable dips from 40' east to vertical to 65' west. Set III is a minor set al- though locally pronounced in the northwest and southwest quadrants. In the northeast quadrant, the average strike and dip are 005' and 60' east. In the southeast, the strike and dip are generally 350' and 650 west (WJ-7). Fracture and shear zones parallel to Set III were mapped in structural areas GF 6A, GF 6B, and in the "Fingerbuster" (Figure 6.3). At GF 6B, Set III forms numerous open joints on the cliff face. Where present, the Set III joints range in spacing from less than 1 inch in fracture zones to 5 feet, with an average of 1.5 feet. These joints are gener- ally planar to irregular and rough. Minor carbonate was ACNES 610 found at some outcrops in the southwest quadrant. Moder- ately to steeply east -dipping Set III joints are likely to be encountered in tunnels near the proposed dam centerline and at the diversion tunnel outlet. Joint Set IV consists of numerous low angle (dipping less than 40°) joints of various orientations, the strongest trend being 090' (Table 6.2). In all but the northeast quadrant, these joints dip towards the Susitna River at less than 30°. In the northeast quadrant, dips are both towards and away from the river. Set IV joints are planar to irregular, smooth to rough and discontinuous. Spacing is generally 1 to 2 feet when present. No mineralization, shearing, fracture, or alteration zones are associated with this set. Set IV joints probably resulted from stress relief after glacial unloading and/or erosion of the river valley, and therefore should not occur at depth. At WJ-2 and WJ-4, a strong local joint set striking approx- imately 3350 with a 30' to 70' dip to the southwest was mapped. Minor shears parallel to this set were found near WJ-4. This set may be encountered in tunnels downstream from the centerline. In summary, shears, fracture zones, and alteration zones at the Watana site tend to parallel Joint Sets I and III. No major structures were found associated with Sets II and IV. The Susitna River appears to be joint -controlled at the Watana site. In the upstream area, the river parallels Set 11. In the dam centerline area, it is controlled by both Set I and Set II, while downstream from the centerline the river is controlled by shear and fracture zones related to Joint Set 1. Shears, Fracture Zones, and Alteration Zones This section defines and discusses shears, fracture, and alteration zones and combinations of these features which are shear/fracture zones and shear/alteration zones mapped at the Watana site. Symbols denoting these features on the geologic sections (Figures 6.4 through 6.8) are: shears (S), fracture zones (F), alteration zones (A), shear/alter- ation zones (S, A), and shear/fracture zones (S,F). For the most part, these features are less than 10 feet wide and discontinuous. Where more than 10 feet wide, both boundaries have been delineated on the geologic map (Figure 6.3) and geologic sections. The individual characteristics of shears, fracture zones, and alteration zones are des- cribed below, while Subsection (iv) discusses the specific areas in which these structures occur. s „ RCNlS - Shears Shears are defined as a surface or zone of rock fracture along which there has been measurable displacement and is characterized by breccia, gouge, and/or slickensides in- dicating relative movement. Two types of shears are found at the Watana site. The first type, which is found only in the diorite, is called healed shears and healed breccia. This type of shear consists of a diorite breccia healed within a matrix of aphanitic to fine grained andesite/diorite. The diorite fragments range from less than 5 percent to 90 percent of the zone and are generally subrounded. The matrix and rock fragments, which are observed in both outcrop and core borings, are fresh and very hard to hard. Figure 6.11 shows a 1-to-2-foot-wide healed sheared zone. The contacts, although irregular, are tight and unfractured. In outcrops, healed shears and breccia range from less than 1 inch to about 1.5 feet. One foot offsets of these features have been observed where they cross f elsic dikes. Two general orientations were found for this type of shear: 305' dipping 45' to 70' northeast, and 300' dipping 65' southwest. Healed shears and breccias were found in virtually all boreholes. In all cases, the zone was found to be compe- tent with high RQDs and high core recoveries. The largest healed shear was up to 140 feet thick in COE DH-11. No correlation could be made between the healed shears and brecci as noted in the cores and the surface exposures. Therefore, these features were not delineated -on the site geologic map. These features are interpreted to be emplacement type shears which formed during the last phases of plutonic activity when the magma was in a semi -solid state. The second type of shear found at the site is common to all rock types and consists of unhealed breccia and/or gouge (Figure 6.18). The breccia consists of coarse to fine sand -size rock fragments in a silt or clay matrix. Gouge is generally silt or clay material. Both the breccia and gouge are soft and friable. Thicknesses of these shears vary from less than 0.1 inch up to 20 feet, but are generally less than 1 foot. Carbonate and chlor- ite mineralization are commonly associated with these shears. Some shears are partially to completely filled with carbonate. Slickensides are found in most shears and occur on both the carbonate and chlorite surfaces. These shears are most often associated with fracture and alteration zones. When found in association with these ROES a.a zones, they have been referred to as shear/fracture and shear/alteration zones. Figure 6.18 is a photograph of a typical shear which is within a fracture zone. These zones will be discussed in more detail in the Fracture Zone and Alteration Zone subsections. - Fracture Zones Fracture zones are areas of very closely to closely spaced (less than 1 foot) jointed rock where no apparent relative movement has occurred. Fracture zones are com- mon to all rock types and are found in both outcrop and boreholes. Fracture zones in outcrop were found to range from 6 inches up to 30 feet in width but are generally less than 10 feet. In the boreholes, fracture zones were found to range from less than 1 foot up to more than 100 feet wide as measured in BH-2. However, for the most part in boreholes and outcrop, the fracture zones are less than 5 feet wide. Where exposed, they are easily eroded and form topograph- ic lows or gullies, which have become filled with talus. The fracture surfaces are generally iron oxide stained. A coating of white carbonate is also commonly found on the fracture surfaces. - Alteration Zones Alteration zones are areas where hydrothermal solutions have caused the chemical breakdown of the feldspars and mafic minerals. The products of alteration are kaolini- tic clay from feldspar and chlorite from mafic minerals. These zones are found in both the diorite and andesite porphyry but appear to be less common in the andesite porphyry. Most of the information regarding alteration zones is from the boreholes. Alteration zones are rarely seen in outcrop because, like the fracture zones, they are rela- tively easily eroded and tend to form gullies which sub- sequently become filled with talus. Alteration zones are exposed on the surface on the north bank in "The Fins" and in one outcrop at river level near the dam center- line. The degree of alteration is highly variable rang- ing from slight, where the feldspars show discoloration, to complete where the feldspars and mafics are completely altered to clay and chlorite. In slightly altered dio- rite, the rock is bleached to a yellowish green or gray and is generally hard to moderately hard as seen in BH-3 from 933.2 to 948.9 feet (Appendix B). The slightly altered zones have approximately 10 to 25 percent of the 13 RCNIS feldspars stained or altered to clay. In completely al- tered diorite, the rock is bleached to whitish gray or very light yellowish gray. The rock fabric is preserved; however, the material is soft and friable. These com- pletely altered zones are uncommon, and when encountered, are generally 1 to 2 feet wide. Most alteration zones found in the boreholes are slightly to moderately al- tered. These zones are moderately hard with some thin soft zones. Figure 6.15 is a photograph of an alteration zone within "The Fins". As seen in the figure; the in- tact diorite is in the upper right and is noticeably darker than the lighter, bleached diorite that is altered and sheared. Iron oxide staining is visible over a 2-to- 8-inch-wide carbonate band. Widths of these alteration zones most often range up to 20 feet but are generally under 5 feet. An exception is in BH-12 on the south bank which drilled over 300 feet into an alteration zone (Figure 6.5, see Subsection Eiv]), Several shear/alteration zones are exposed in "The Fins" and range from 10 to 55 feet wide. The carbonate, which is also associated with the altera- tion zones, occurs as veins or joint filling generally up to 0.5 inches thick. Occasionally, sulphide mineraliza- tion and iron oxide staining are also found in these zones. No increase in joint frequency is evident in association with these alteration zones. Numerous thin (C2 inches) shears are associated with the alteration zones (Appendix B). RQDs are generally low, because only fresh to slightly altered rock is considered in taking RQD mea- surements. Core recovery is generally more than 90 per- cent within the alteration zones. The transition from fresh to altered rock is gradational, generally occurring over less than 1 foot. (iv) Significant Geologic Features The Watana site has several significant geologic features which consist of broad areas of shears, fracture zones, alteration zones, and/or combinations of these features. Two of these areas, initially mapped by the COE (45) are called "The Fins" and "Finger buster" (Figure 6.3). Other areas or individual structures considered to warrant detailed discussion have been identified on Figure 6.3 by letters GF 1 through GF 8 and are discussed individually below. RCRIS 61< - "The Fins" "The Fins" consists of major zones of shearing and alter- ation. This feature is located on the north bank of the Susitna River upstream from the proposed diversion tunnel intake portal (Figure 1.2). "The Fins" consists of a 400- foot-wide zone containing a series of northwest trending shear/alteration zones. Gullies formed by erosion of these structures are separated by intact rock bands or ribs ranging from 5 to 50 feet wide. Three major and numerous minor shear/alteration zones have been mapped in "The Fins." From upstream to down- stream, the major zones consist of a 20-foot-wide zone in the area of the diorite and diorite porphyry contact; a 55-foot-wide zone; and a 30-foot-wide zone. These zones are separated by intact competent rock bands or ribs. Large gullies with thick talus have formed in these zones, resulting in poor rock exposure. These zones trend in a northwest -southeast direction and are near vertical. Figure 6.16 is an aerial photograph of "The Fins" looking northwest along the strike. The 55--foot- wi de gully (as measured at river level) splits into two branches 20 to 30 feet wide at approximate Elevation 1650. A 10-foot-wide zone of altered and crushed rock is exposed near river level on the east side (Figure 6.15), and there is a 3-foot-wide zone of sheared/fractured and moderately to severely altered rocks on the west side of the main gully. The remainder of the gully is covered by talus. Based on these exposures, it has been assumed that the shear and alteration zones extend across the full 55-foot width of the gully. There are carbonate veins parallel to these zones and others which transverse them. Carbonate thicknesses range from 0.5 to 8 inches. The veins are fractured but no offsets were noted. Minor east -west and north -south trending shears also occur in "The Fins." These features are generally less than 1 foot wide. Two north -south trending shears mapped in "The Fins" are 1 foot and 3 feet wide, respectively, and dip 57' to the west. Slickensides on carbonate coat- ings indicate an oblique sense of movement. Figure 6.14 shows a 3-foot-wide north -south shear. This shear appears to project across the river in the vicinity of the upstream cofferdam and align with a topographic trend on the south bank. Lineations associated with the north - south shears are indicated on Figure 6.16. s-,s �CNlS The overall trend of "The Fins" is 300 to 3100. Dips are steep to vertical. The extension of this feature to the northwest is inferred from seismic refraction lines SL 81-15, SL 81-15x, and SW-3 which show low seismic velo- cities (10,000-12,700 feet per second) in bedrock, as well as low bedrock elevation along the projection of "The Fins" (Figure 6.5). In contrast, the bedrock seis- mic velocity northeast and southwest of this feature is about 18,000 feet per second (Appendices H and I). Beyond the seismic lines, "The Fins" has been inferred to trend along a topographic low (Figure 6.16). Altered rock found in CO£ boreholes DR-18, DR-19, and DR-20 in Borrow Site D may also have been drilled in this feature (Figure 5.1). The topographic low projects to Tsusena Creek, where along the northwest bank, an altered and sheared outcrop of granodiorite is exposed. This outcrop exposure is approximately 325 feet wide and is character- ized by northwest, north -south, and east -west trending shears. The continuation of "The Fins" to the southeast beyond the south bank of the Susitna River is uncertain. On the south bank across from "The Fins," there is a topographic low in Quarry L (Section 6.3[i]), which is the inferred location of "The Fins" structure. Beyond this area, no outcrops or topographic trends could be correlated to this feature. The trace of this feature is also support- ed by mapping activities performed by Woodward -Clyde Con- sultants during their seismic studies carried out during 1980-81 (57,58). . Geologic Feature GF 1 GF 1 is the region downstream of "The Fins" in the vic- inity of the proposed upstream cofferdam.and diversion tunnel portals. For discussion purposes, the area has been divided into two subareas: GF 1A on the north bank and GF 1B on the south bank (Figure 6.3). Subarea GF 1A contains east -west and northwest -south- east trending shears and fracture zones. The east -west shears are oriented between 2800 and 2900 with vertical dips. Shear widths are generally 1 foot or less. The northwest -southeast (310 to 320°) trending shears are up to 3 feet wide and are parallel to two fracture zones. These zones are 25 to 30 feet wide and form gullies. These features are likely to be encountered in the proposed diversion tunnels (Figure 6.7), intersect- ing the tunnels at high angles (Figure 6.3). The most significant structure in GF 1B is a 20-foot-wide frac- RCRfSs-,fi ture zone trending at 315' and dipping vertically. A 1-foot-wide zone of possible gouge was found in the zone. Approximately 100 feet to the northeast, a 4- inch-wide shear was mapped parallel to this fracture zone. The correlation of the structures in GF 1A with those in GF 1B are uncertain. . Geologic Feature GF 2 GF 2 (Figure 6.3) is approximately 80 feet wide and consists of northwest -southeast trending fracture zones with minor shears. On the south bank, GF 2 is coinci- dent with a deep, talus -filled gully. Outcrops on either side of the gully are very closely jointed (Set I). Dips are vertical or steep to the north. On the north bank, there is no strong topographic ex- pression of the GF 2 structure. A 30-foot-wide gully postulated as a fracture zone was mapped at about Ele- vation 1700. Joint orientations in this area are simi- lar to those on the south bank. The GF 2 structure was projected farther to the northwest in alignment with a low seismic velocity (14,800 feet per second) zone on SL 80-3 (Appendix I). Based on this evidence, it is likely that this fracture zone will be encountered in the diversion tunnel (Figure 6.7), intersecting the tunnel at an oblique angle. . Geologic Feature GF 3 GF 3 is located on the south bank (Figure 6.3). This area contains fracture zones and minor shears. These structures strike predominantly at 320' and have verti- cal to steep northeast dips. A 20-foot-wide fracture zone was mapped in a deep gully paralleling Joint Set I. Parallel to this zone is a 4-to-6-foot wide zone of brecci a with heavy carbonate coating. Also in GF 3 is a 3-to-6 foot -wide shear/fracture zone which trends north -south and dips 60' east. No features similar to those in GF 3 were found on the north bank. . Geologic Feature GF 4 GF 4 consists of two shear/fracture zones OF 4A and GF 4B), each about 10 feet wide (Figure 6.3). The overall trend of these zones is 315' with a dip of 70' to the east. On the south bank, GF 4A and GF 4B were mapped in a very deep, talus -filled gully. Outcrops in the gullies have very closely to closely spaced joints along Joint Sets I, II and III. All joints are heavily carbonate coated. Where mapped, GF 4A was 6.,, WCflES found moderately weathered with possible alteration. Seismic velocities in this area (SL 80-3) are lower (15,000 feet per second) than the usual 18,000 tc 20,000 feet per second velocities measured in less fractured diorite. GF 4A and GF 4B have been projected across the river to correlate with two fracture zones mapped between Elevations 1650 and 1750. These frac- ture zones are also in a deep gully (Figure 6.17). GF 4A has been tentatively correlated with the shears, fracture zones, and alteration zones found in borehole BH-3 (Figure 6.4) between borehole depths 414.4 and 622.4 feet. These zones are slightly to moderately altered and generally moderately hard, though locally soft and friable in the shears. RQDs between 474 and 530 feet are 0 percent because of the moderate altera- tion. Throughout the rest of the zone, RQDs are 90 t� 100 percent with permeabilities generally 10- cm/sec. Many of the joints are healed by carbonate. The correlation of the zones in BH-3 with GF 4A has been based on the assumption that the zones are trend- ing northwestward. This assumption is supported by the fact that this fracture zone would have been intersect- ed in either BH-4 or DH-11 if it had had an east -west or a north -south strike. GF 4B has been correlated with a shear/fracture zone and alteration zone in DH-11 (Figure 6.4) at borehole depth 189.0--197.7 feet. The fracture zone is iron oxide stained. The upper three feet of the zone is hydrothermally altered and contains 0.2 foot of clay gouge and breccia. Permeabilities in this zone are high, typically ranging between 10' cm/sec to 10-3 cm/sec. Most joints are coated with sandy silt/clay and minor carbonate. The projection of the GF 4A and GF 4B structures would intersect the proposed diversion tunnels (Figure 6.3) at a high angle. . Geologic Feature GF 5 GF 5 is located near the proposed dam centerline and consists of fracture zones and minor shears (Figure 6.3). The area is approximately 60 to 70 feet wide and trends northwest -southeast (310 to 320°). The dip is steep to the northeast. GF 5 on the north bank of the river falls within a deep gully bounded on the down- stream side by a 75-foot-high diorite cliff (Figure 6.17). Two northwest trending shears in the gully are as much as 10 feet wide and dip at 75' and 80' to the northeast and southwest, respectively. Although there is no topographic expression of these features on the north abutment, it has been correlated with several �CBES 6-19 shear and fracture zones intersected in borehole DH-9 (Figure 6.4) and with a 130-foot-wide, low -velocity zone on SW-2 (12,500 fps) (Appendix I). The joints and fractures in DH-9 are generally iron oxide -stained and carbonate -coated. Faint slickensides are observed on some surfaces. The RQDs in DH-9 are low, with an aver- age of 57 percent. Permeabil3ities are generally be- tween 10-1 cm/sec and 10- cm/sec and decrease with depth. No low -velocity zones were encountered along SL 80-2 (Figure 6.3) that could imply continua- tion of this feature to the northwest (Appendices H and 0. On the south bank, the GF 5 structure is correlated to a 10-foot-wide fracture zone at river level and a ser- ies of minor northwest -trending shears between Eleva- tion 1650 and 1850. Farther up slope, it is correlated with a moderately low (15,000 feet per second) velocity zone along SL 80-3 and a bedrock depression found in borehole DH-25 (Figure 6.8). In this area, overburden thickens from 10 or 15 feet to nearly 80 feet. On the north bank, GF 5 will likely intersect the proposed diversion tunnels (Figure 6.3). . Geologic Feature GF 6 GF 6 is divided into two subareas: GF 6A on the north bank and GF 6B on the south bank (Figure 6.3). Both subareas are characterized by north -south trending structures. GF 6A is approximately 25 feet wide and occurs in a north -south trending gully whose walls are very closely jointed, severely weathered, possibly al- tered, and locally friable. A strong north -south trending joint set (Set III) with vertical and steep dips occurs in this area. Subarea GF 6B is characterized by north -south shears, fracture zones, and open joints; east -west trending open joints; and northwest trending shears (Figure 6.3). These features are exposed in deep gullies in the high rock cliff face on the south side of the river (Figure 6.18). The north -south shears have up to 2.5 feet of gouge. Open joints along this trend generally dip at about 800 to the east and are up to several feet wide. East -west trending joints dip 700 to 80' north towards the river. The intersection of these joint sets has resulted in block slumping. Details of northwest trending shears in GF 6 are discussed in GF 7 below. No direct evidence could be found during this study to correlate GF 6A and GF 6B. 6-19 ,ACflfS . Geologic Feature GF 7 GF 7 is divided into three subareas: GF 7A on the north bank; GF 7B, which trends across the river from the north bank to the south bank; and GF 7C, which lies between these two areas on the north bank (Figure 6.3). GF 7 is characterized by numerous northwest (290' to 300°) trending, nearly vertical shears. These shears are generally 1 foot or less wide and are often associ- ated with fracture zones up to 10 feet wide. Subarea GF 7A is about 40 feet wide and lies in a shal- low northwest trending gully. An outcrop on the east side of the GF 7A structure at approximate Elevation 1850 is a moderately soft, altered diorite. The extent and orientation of GF 7A are uncertain; however, based on field mapping, it appears to trend in a northwester- ly direction. On the north bank in the andesite porphyry, subarea GF 7B lies in a deep, vegetated gully trending at 290' (Figures 6.3 and 6.19). Exposures in the gully show very closely spaced vertical fractures trending approx- imately 290° with thin zones of breccia and gouge. The andesite porphyry on the gully walls is slightly to moderately weathered. Figure 6.20 shows where GF 7B intersects the "Fingerbuster" at river level on the north bank (see next subsection). Subarea GF 7B has been projected across the river to correlate with fea- tures exposed along the base of the cliffs in area GF 6B (Figure 6.3). GF 7B appears to dip at 75' to the north. This is based on the slope of the cliff face and dips of shears behind and at the base of the cliff. GF 7B was also correlated with a shear zone intersected from 97.8 to 104.0 feet in DH-1 (Figure 6.6). This zone is slightly to moderately altered, with shears less than 6 inches wide. The rock is moderately hard, but soft in shear zones. RQDs are generally less than 40 percent in DH-1 with permeabilities about 10-3 cm/sec. Shearing may also exist in DH-3 where core 1 osS of 6. 7 feet occurred near the top of rock between'.' 94.0 and 104.7 feet. Subarea GF 7B projects to the southeast from the river bank and is exposed in a steep -walled, 10-to-15-foot wide gully at the andesite porphyry/diorite contact at Elevation 1750. GF 7B crosscuts both of these rock types. The rock in the zone itself has a granular nearly schistose character typical of cataclastic rocks. The rock has been healed and resheared. No exposures of GF 7B were found beyond this point; however, it has been tentatively correlated to a 10,000-feet-per-second zone on seismic line SW-1 RCBf3 6 =0 and to shear/fracture zones in DH-23 (Figure 6.5). This correlation is questionable, since the zone was not intersected by BH-8, which lies between these fea- tures. Subarea GF 7C is bounded by the "Fingerbuster," subarea GF 7A and a north -south trending gully on the east side (Figure 6.3). This area has a step -like appearance in section because of a series of east -west trending ridges and gullies between 10 and 20 feet wide. The "steps" trend along the 290' to 300' shears which are parallel to Set I joints in this area. Numerous minor shears in this area have resulted in gullying and ero- sion. This area was interpreted to be a series of near -surface slumps along the northwest -trending shears. It is assumed that GF 7C extends to near Ele- vation 2200, where a low -velocity zone was found on SW-2. The size and stability of these blocks will require investigation in subsequent phases of work. - "Fingerbuster" The second most prominent structural feature at Watana is the major zone of shears called the "Fingerbuster," lo- cated about 2,000 feet downstream of the proposed dam centerline. On the north bank, this structure is par- tially exposed in a 40-foot-wide gully filled with a deep talus deposit. The andesite porphyry/diorite contact is coincident with this structure to about Elevation 2000. An outcrop in the gully 100 feet above river level is a highly fractured diorite breccia in an andesite matrix. The rock is moderately to severely weathered. Joints are very closely to closely spaced in the gully, trend 330' (Set I) and 00 (Set III), and dip steeply to vertical. Slickensides on the gully walls indicate a vertical dis- placement. Another outcrop at Elevation 1850 on the east side of the gully is very fine to medium grained diorite which has been intruded by thin veins of andesite con- taining diorite fragments. BH-2 was drilled across the "Fingerbuster" structure to determine its location at depth. Between borehole depths of 71.2 and 177.1 feet, the borehole intersected a shear/ fracture zone which was also coincident with the andesite porphyry/diorite contact at approximately 126 feet (Fig- ure 6.7). The rock in this zone contains major shears and zones of alteration. RQDs and core recoveries were gen- erally less than 50 percent and often 0 percent. A gully that branches from the main "Fingerbuster" to the north- west is inferred to be another shear and fracture zone. _1 RCRE3 The extension of the "Fingerbuster" to the south is based on a strong north -south topographic lineament which ex- tends to Elevation 1800 on the south bank. No outcrops were found in this gully. This feature, which is down- stream from the main dam structure, has been considered significant in design. Every effort has been made to avoid placing major civil structures in this area. . Geologic Feature GF 8 GF 8 is a wide (approximately 400 feet) northwest - trending structure on the south bank of the river which consists primarily of alteration zones but also in- cludes shear and fracture zones (Figure 6.3). This area was delineated during the 1981 field season for a possible underground powerhouse on the south bank. As a result of the scarcity of bedrock exposure in this area, all geologic interpretation has been based on seismic refraction surveys and drilling. In 1981, an 1,800-foot seismic line (SL 81-21) was shot along a northeast -southwest trend across the south bank (Figure 6.3). A zone about 1,100 feet long of low seismic vel- ocity in bedrock was found. Velocities were about 12,000 feet per second in this zone and 18,000 feet per second in the adjacent zones on each side. Poor qual- ity rock was confirmed by BH-12 which was drilled to the southeast to intersect this structure (Figure 6.5). At about Elevation 1700, the boring encountered a near- ly continuous zone of altered diorite with minor shears. Alteration is generally slight but includes zones of moderate to severe alteration. Shears are less than 6 inches wide. Joints are generally closely spaced and healed with carbonate. Chlorite is found on some joint surfaces. The trend and dip of this structure was based on corre- lation between SL 81-21, SW-1, BH-12, and DH-28. DH-28 was drilled vertically to a depth of 125.2 feet in an-- desite porphyry. The rock in the boring is slightly to moderately altered and moderately hard. Joints are very closely to closely spaced and iron oxide stained throughout. RQDs are generally less than 50 percent and often 0 percent. It is postulated that DH-28 was drilled in a shear/fracture zone related to the GF 8 structure (Figure 6.8). East of OH-28, SW-1 shows zones of alternating high (17,500-20,000 feet per second) and low (12,000-13,000 feet per second) seismic velocity bedrock. No evidence of shearing or altera- tion was found in BH-8, DH-12, DH-23, or DH-24 or in any outcrops on the south bank (Figure 6.5). This ACNES s =_ observation served to limit the northeastward extent of GF 8. In defining the trend of GF 8, it was assumed that this structure would follow the major northwest - southeast structural trend found at the site. The southwest limit of GF 8 was based on the change from low to high bedrock velocity on SL 81-21. The south- west contact was assumed parallel to the northeast limit. The dip of the structure, based on the seismic line and information from BH-12, is assumed to be about 700 to the southwest (Figure 6.5). (d) Rock Quality Designation The Rock Quality Designation (RQD) (13) was determined for all rock cores drilled by Acres and COE and is graphically shown on the Summary Logs in Appendix B. Excluded from this series of bor- ings are COE DR-16, DR-17, DR-18, DR-19, DR-20, and DR-22 which were rotary drilled without core recovery and, therefore, no RQDs were obtained. A tabulation of the RQD values is provided in Tables 6.3 and 6.4. As noted in the tables, rock quality encoun- tered in the drilling was generally good to excellent with RQDs averaging between 75 and 90 percent. In general, rock quality improves with depth, with the upper 50 to 80 feet of rock being weathered and more fractured. Below this weathered zone, rock quality is good to excellent with only localized zones of frac- tured and sheared rock. These zones generally range in thickness from 1 to 5 feet, but can be up to 30 feet. RQDs correlate well with the permeability tests (Section 6.lEfl) which is generally a function of rock quality. Poor quality rock was found in BH-2 which drilled through part of the "Fingerbuster" shear zone. This borehole was sited downstream from the zone and drilled at an azimuth of 045' and a dip of 55°. As seen in the boring logs, the shear zone was intersected at a borehole depth of approximately 70 feet and continued to a hole length of approximately 100 feet (vertical depth 65 to 80 feet). This zone, which corresponds with the andesite porphyry/diorite contact, consists of highly fractured, severely weathered brec- ciated and sheared rock. Repeated grouting was required to main- tain hole stability. Below this zone, rock quality improved with only localized zones of low RQDs encountered around borehole depth of 200, 210, and 250 feet. Other poor quality rock was encoun- tered in several shallow COE holes (DH-1 and DH-28). These holes were drilled to a depth of less than 125 feet and reflect the poor quality, near surface weathered rock conditions. In general, weathering appears to be primarily physical in nature, with weathered rock being about 40 feet deep at the damsite. The weathering is light to moderate in joints, with penetration gener- ally less than a inch into the unbroken rock. Shear and fracture zones are considerably more weathered, and many of the shear zones e-=3 ACflISI exhibit chemical weathering and hydrothermal alteration. Details of these zones are discussed in Section 6.1 (c). The intact rock is classified as Class B "high strength" and has a high static modulus to compressive strength ratio of 500. Rock overall classification is Bpi (14). (e) Rock Properties Representative NQ (1.77 inches) rock core samples of andesite por- phyry, diorite, quartz diorite and granodiorite samples were sel- ected from Bpi -I, -2, -3, -4, -6, -8, and -12 for laboratory test- ing. Results of the testing are presented in Tables 6.5 and 6.6 and are discussed below. Since the properties of diorite, quartz diorite, and granodiorite were found to be similar, they have been included under the heading of diorite. Photographs of typical rock testing is shown in Figure 6.21. (i) Unit Weight Dry unit weights were determined in conjunction with com- pression and tensile strength tests. Dioritic rocks aver- aged 167 pcf and andesite rocks averaged 165 pcf. (ii) Static Elastic Properties Elastic properties were measured under unconfined compres- sion using electronic strain gages bonded onto the sample in horizontal and vertical directions. Stress, diametric strain and volumetric strain were calculated and plotted against axial stress from which the tangent modulus at 50 percent failure stress, secant modulus, and Poisson's Ratio were determined. Results are presented in Figure 6.22. An average of all test results shows: Static Modulus Poisson's Rock Type (x 10psi) Ratio Andesite 10.2 0.25 Diorite* 9.5 0.23 Combined, all samples 9.64 0.24 *Includes diorite, granodiorite and quartz diorite (iii) Dynamic Elastic Properties Compressional (Vp ) and shear (Vs) wave velocities were measured on two dioritic samples giving: Dynamic Modulus (x106 spi) 10.1 (iv) Direct Shear Tests vp vs Poisson's Ratio (fps) (fps) 0.31 19508 10267 Three types of direct shear tests were performed: (1) Natural discontinuity (2) Polished rock on rock (3) Polished rock on mortar Test results are plotted on Figure 6.23. A summary of the results are: Diorite Natural joint, rough, planar with carbonate, dry Natural discontinuity with inferred cohesion Polished rock on rock, dry Polished rock on mortar, dry Polished rock on mortar, dry with inferred cohesion Peak 0 Residual C (psi) 380 280 0 300 29 21.50 180 0 440 310 0 310 24 Polished rock on rock tests give a material's lowest fric- tion angle. This angle does not include effects of natural surface undulations or roughness. Therefore, a "waviness angle" is applied to obtain a more representative value for design. This "waviness angle" is based to a 'large degree on observed field conditions of natural joint surface and site geology. The results of the natural joint test quoted above show relatively high peak and residual values. Analysis of ver- tical vs. horizontal displacements shows a 10' incline, which appears to reflect this "waviness angle" for in situ conditions. As noted on Figure 6.23, two possible inter- pretations of the shear strength are given: a higher peak without cohesion or a lower peak including an apparent co- hesion. The results are typical of natural joints and rock on concrete (21). Diorite on mortar tests show that the shear strength is initially high but decreases to residual values with higher normal loads and greater displacements. 6.25 ACdS (v) Compressive Strength Testing Compressive strengths were measured in unconfined compres- sion and by point loading. - Unconfined Compression Results of unconfined compressive strength tests show: Number High Low Mean + Standard Rock Tye Of Tests_(psi)(psiDeviation ipsil Andesite 8 26,206 6,100 18361 + 5978 Diorite 32 29,530 4,473 17593 + 6080 Both rock types are isotropic and show relatively high strengths. Frequency plots (Figure 6.24) show 90 percent of all cores tested above 10,000 psi and approximately 70 percent of results plotted between 11,755 and 23,736 psi. - Point Load Testing Boreholes BH-6 and BH-8 were profiled at 15-to-20-foot intervals using a Terremetrics T-500 point load tester. Frequency plots (Figure 6.25) show 95 percent of all test results are more than 10,000 psi and, assuming a normal distribution, nearly 70 percent of all tests fall within the 18,114-to-38,390-psi range. No distinction between the various rock types could be noted. These apparent strengths are substantially higher than those defined by unconfined compressive strength tests. The probable cause is that rock strength is proportional to the physical dimension of the test sample. For uncon- fined compression tests, lower strengths for larger size cores of the same rock are common (23). Since a poi nt load tester tests the minimum volume of rock, higher results would be expected. Both types of tests, however, show the intact rock to be of high strength with an average to high modulus ratio (BM, BH) (14). (vi) Tensile Strength Number of High Low Mean + Standard Rock Type Tests(psi) (psi) Deviation (psi) Andesite 3 1718 1616 1683 + 58 Diorite 8 2450 602 1906 + 576 IACAJ 626 Test results show that intact rock tensile strength (Braz- ilian Split) is relatively high, which implies a high in- tact rock shear strength. The lowest strength was obtained on altered diorite sample while sound, competent cores tested at least three times higher. ( v i i ) S u_ mina ry The rock test results presented in this section are con- sidered adequate for preliminary design purposes. Exten- sive geotechnical work including drilling, down -hole test- ing, geophysics, exploratory adits, laboratory and in situ testing, will be required before the final design para- meters can be determined for each structure. However, tests performed during this, as well as previous studies, show the rock to be of excellent quality for constructing both surface and subsurface hydropower facilities at Watana. (f ) Rock Permeabi 1 ity Water pressure tests performed both by the COE and Acres (Section 5) confirm that rock permeability at Watana site is controlled by the degree of jointing, fracturing, weathering and permafrost within the bedrock. Results of permeability tests are graphically shown on the Summary Logs and tabulated in Appendices B and D, respectively. Water pressure testing could not be performed in several zones because of hole caving. In BH-2, testing was terminated at a hole depth of 70 feet, and in BH-12, the bottom 200 feet could not be tested. The rock permeability does not vary significantly within the site areg, generally ranging between 1 x 10-4 cm/sec to 1 x 10- cm/sec. As would be expected in fractured rock, high permeabilities are found near the surface with low permeabilities at depth (Figure 6.26). Similarly, high permeabilities are also encountered in the more highly fractured rock zones. An example of this was fond in BH-1 (Appendix B) where higher permeabilities, about 10- cm/sec, were measured in a zone from 150 to 160 feet, which corresponds to a highly fractured zone with 0-RQDs and low cor recovery. Similarly, high permeabili- ties, about 1.6 x 10- cm/sec, were measured in BH-6 at a depth of 464 feet, which corresponds to a soft mineralized zone with 0-RQDs. -_7 ACBES In BH-3 and BH-4, at the estimated powerhouse cavern depth of approximately 1450 to 1400 Elevation, permeabilities are low, in the range of 2 x 10-6 cm/sec. The permeability of rock above the powerhouse complex is generally low, ranging between 1 x 10-5 to 1 x 10-6 cm/sec. Artesian conditions were encountered in BH-12 at a depth of 325 feet, which corresponded with the granodiorite/andesite altered and sheared contact. Because of the structural relationship of these two rock units (see Section 6.1 [b]), higher permeabilities may be expected where this contact is intersected. Permafrost conditions within the rock have an effect on permeabil- ity. Ice -filled joints and fractures prevent water from flowing through the rock mass, thereby giving erroneously low permeability values (Section 6.1 [h]). Thawing methods have, therefore, been developed in those permafrost areas for foundation treatment under the dam and associated structures. (g) Groundwater (i) General As stated in 6.1(b), the Watana damsite lies within a large dome -shaped diorite pluton. Groundwater data for the site is based on borings, installed piezometers, and field ob- servations. This section will address only the groundwater conditions at the damsite and construction areas. Discussions of the groundwater in the borrow sites and relict channel will be individually addressed in Sections 6.2 and 6.3, respec- tively, while the groundwater conditions in the reservoir are briefly discussed in Appendix K. (ii) Damsites For the most part, the groundwater at the main damsite is confined to open fractures and joints within the bedrock. Therefore, the movement of groundwater is determined by the rock permeability and continuity of these open fractures and joints. Gradients within the damsite proper are down - slope towards the Susitna River, with the groundwater gen- erally representing a subdued replica of the topography. The groundwater regime is complicated at the Watana site by the existence of nearly continuous permafrost on the south bank and possibly intermittent permafrost on the north bank (Section 6.1 [h]). As a result of the permafrost, the groundwater table is relatively shallow on the left abutment. Boreholes BH-8, BH-12, DH-12, DH-25, and DH-28 all encountered water levels within 10 feet of the surface. Numerous seeps, springs, and wet areas are evident throughout the left bank. This shallow water table is the "thawed" layer perched on top of the permafrost zone. On steeper slopes (Elevation 1900 to river level), groundwater flows through the weathered rock zone and on top of the rock surface beneath the talus slopes. Groundwater was encountered in two deep boreholes beneath the permafrost on the south bank. In BH-8, the water level was recorded at approximately 170 feet, whereas BH-12 intersected artesian conditions at hole depth 350 feet or approximately 200 feet beneath ground surface. (This depth corresponds with the mapped sheared and altered zone [GF 81 on the left abutment [Figure 6.31). This hole, which was drilled in 1981, has continuously flowed at several gallons per minute since it was drilled. During its drilling, water was noted flowing from an adjacent borehole (immedi- ately uphill from BH--12) indicating communication along this zone. Further investigations and instrumentation will be required in subsequent phases of study to accurately define the groundwater conditions in this area. Groundwater on the north abutment has been monitored by piezometers installed in BH-3 and BH-6. Based on this data, the groundwater table appears to be deep on the north bank. Water levels monitored in BH-6 and BH-3 show the water table to range between 107 to 150 and 280 feet below ground surface, respectively. The fluctuations noted in BH-6 appear to be directly correlative with changing season precipitation. (iii) Subsurface Structures Structures such as penstocks, powerhouses, and transformer galleries that will be constructed below the groundwater table will likely experience water inflows through open joints, fractures, and shears. However, rock permeabili- ties in these areas are expected to be low (Section 6.1 [fD - (iv) Surface Facilities As stated in (ii), any surface structure on the south bank can expect to encounter a perched water table on top of the permafrost. Shallow structures on the upper portions of s.=s RLCBfS the north bank are likely to be above the water table, while structures near river level will likely intersect the phreatic surface. The construction of the Emergency Spillway will likely en- counter groundwater within the shallow overburden and weathered rock where perched water table and aquicludes can be expected. Camp facilities are sited within the relict channel and can expect a surface water condition during the summer thaw. The groundwater table in this area is addressed in Section 6.2. (h) Permafrost (i) General The Watana area has-been mapped as a zone of discontinuous permafrost (19). Permafrost features consisting of frozen tills, bimodul and solifluction slides, beaded streams, thermokarst topo- graphy, skin flows, collapsed pingos, and thaw lakes are found throughout the region. Based on regional temperature readings from the Summit and Cantwell, Talkeetna and Curry areas, it appears that the site is very near to the freezing isotherm, which is sup- ported by one year's temperature data for Watana that show an average temperature of approximately 0.5% (37). These temperatures suggest that the site is in an area where there is no ongoing development of permafrost. Thermistor readings at the damsite and borrow sites are shown in Figures 6.27 through 6.29. An analysis of this data is contained in the following subsections and Sections 6.2 and 6.3. (ii) Damsite As previously stated, permafrost appears widespread throughout the left abutment. All of the seven boreholes drilled on the left abutment, except BH-12, froze back within 30 feet of the surface. Permafrost was measured throughout the full hole depths in DH-12, DH-23, DH-24, DH-28, and to a minimum depth of 175 feet in BH-8 where the instrument was blocked. lacAisl 6-30 A total depth of permafrost in the left abutment is esti- mated to be 200 to 300 feet. Temperature readings, how- ever, show this to be "warm" permafrost with readings gen- erally ranging between 0 and -1°C (Figure 6.27). The extent of permafrost in the underlying river alluvium and bedrock is based on information Obtained from DH-21 and BH-6. OH-21 drilled by the COE shows apparent permafrost to the top of rock. No deeper readings could be obtained because of hole collapse. BH-6, drilled on the right abut- ment and inclined beneath the river, shows temperatures below freezing from hole depths ranging from approximately 95 feet to between 200 to 250 feet, or about 100 to 150 feet beneath rock surface (Figure 6.27). Drilling of the vertical holes by the COE in the river alluvium showed no apparent permafrost in either the allu- vium or bedrock. Further investigations will be required, however, in this area to confirm the permafrost condi- tions. No permafrost was encountered in any of the seven borings drilled on the right abutment, with the exception of the previously discussed BH-6. The Only other instrumented hole on this abutment is BH-3, which shows a very consis- tent data plot with a minimum temperature of 1.2% at about 120 feet. Thermal gradients measured in several of the borings show average gradients of about 1% per 200 to 300 feet with the exception of BH-3 which shows a gradient of 1°C per 550,f eet. This lower gradient may be caused by groundwater flows within the rock mass resulting in a decreased temperature. (iii) Surface Structures Excavation for surface structures may encounter sporadic "warm" permafrost or annual frost on the right abutment and more or less continuous permafrost on the left abutment. Annual frost penetration appears to be about 8 to 16 feet in the rock and up to 80 to 50 feet in alluvium. Although no permafrost was found in the areas of the pro- posed Emergency Spillway, for construction purposes, it should be assumed that localized permafrost may be encoun- tered that would require thawing and foundation treatment. (iv) Camp and Access Roads The camp facility has been sited in the general area of the relict channel (Section 6.2). Local areas of permafrost can be expected in this area with zones of deeper seasonal frost encountered beneath the tundra cover. e->1 RCRES Permafrost can also be expected locally along the access and construction haul roads in overburden cuts at depths of 0 to 20 feet. Permafrost in the bedrock is not expected to pose any major engineering constraints. Care will be required in designing cut slopes in permafrost terrain to insure long-term slope stability. Further investigation in these areas will be required to accurately define the perm- afrost conditions. 6.2 - Relict Channels (a) Watana Relict Channel (i) Introduction In 1975, seismic refraction surveys performed by the COE identified a large, deep overburden deposit on the right bank extending between Deadman and Tsusena Creeks. This large, soil -filled depression was interpreted by the COE as a possible relict channel of the Susitna River. Further seismic work was performed in the channel by the COE in 1978 and by Acres in 1980-81. To date, approximately 70,000 linear feet of seismic refraction surveys have been performed in this area. In addition to the seismic work, the COE drilled 8 deep rotary borings in the channel to identify the stratigraphy and to verify the seismic refrac- tion interpretation. Numerous shallower auger holes were drilled in the area during 1980-81 primarily to assess bor- row materials. Figures 5.1 and 6.43 show the extent of exploration performed in and adjacent to the channel area. All of this data has been used in defining the location, configuration, and material properties of the relict chan- nel. The accuracy of the data in defining the extent and configuration of the channel is considered good. Verifica- tion of seismic interpretation for top -of -bedrock by the COE's boring showed accuracy within 10 percent for the 1975 data and 5 percent for the 1978 data. The seismic accuracy of the intermediate soil stratigraphy is not as good, since the principal objective of the sur- veys was to locate top -of -bedrock. Therefore, the survey technique used was not conducive for accurately detailing the intermediate zones. As a result, the stratigraphy within the channel has been based on very preliminary and widely scattered data point (Figure 6.40). The following sections provide a detailed discussion of the Watana relict channel. RCBf3 6 =_ (ii) Location and Configuration The approximate location of the relict channel is shown on photographs in Figure 6.30. The upstream entrance to the channel extends from a location approximately 2,000 feet upstream from the damsite, where bedrock drops below maxi- mum pool elevation (2202 feet), to a point more than two miles upstream from Deadman Creek. The ground surface in the relict channel is flat to gently rolling with a drainage divide trending generally north to northeast through the area which closely corresponds with seismic lines DM -A and DM-B (Figure 6.31). A top -of -bedrock contour map showing surface topography and projected flow paths through the channel are shown in Figure 6.35. The maximum overburden thickness in the thal- weg channel is approximately 450 feet. A sketch showing the relict channel with and without the overburden removed is shown in Figure 6.30. Under the max- imum operating pool level of 2,185 feet, a total of approx- imately 13,500 feet of the upstream portion of the channel would be inundated with water (Figure 6.31). The distance between the proposed reservoir and Tsusena Creek along the shortest distance through the channel would be approximately 6,200 feet and 7,700 feet along the thal- weg section (Figure 6.33). An average hydraulic gradient along the thalweg would be about 1:14. (iii) Geology The formation of the relict channel and the subsequent div- ersion of the Susitna River into its present position is likely the result of a sequence of glacial events during the Quaternary Period (Table 4.1). The Quaternary history of this area is very complex and poorly understood. However, based on work performed by Acres and Woodward -Clyde Consultants (60) during this study, the following geologic events appear to be the most plausible in explaining the existing conditions. During preglacial times, the Susitna River flowed down the relict channel and into the area of Tsusena Creek. The river in this area followed the path of least resistance, being diverted around the more massive diorite pluton (which underlies the damsite) to the south. The relict -» ACRES channel appears to have followed the softer sheared and fractured rock of "The Fins" structure which is traced through this area (Section 6.1). Advancement of the Tsusena Creek glacier into this area from the north and northeast resulted in the infilling and diversion of the Susitna River to the south around the ice margin, where it subsequently downcut through the diorite along existing joint sets (Section 6.1). Once below ap- proximate Elevation 1900, the river fell below the entrance to the relict channel. Several glacial advances and retreats through this area resulted in deposition of a thick sequence of glacially derived material within the relict channel. This material consisted of basal till, alluvium, glacial fluvial silts, sands, and gravels and lacustrine clays. The actual time and number of glacial advances and retreats in this area are unknown. However, this sequence of events appears to be supported by the stratigraphy within the relict channel. (iv) Stratigraphy Based on the drilling in, and adjacent to, the relict chan- nel, a total of 11 stratigraphic units have been identi- fied. They have been designated by letters A through K. These units have been differentiated based on texture, structure, color, mode of deposition and stratigraphic pos- ition. Although facies changes exist in these units, each represents a unique depositional event. The correlation of the deeper units have been based principally on the eight deep holes drilled by the COE (45). Since these holes were drilled over a large area, additional work will be neces- sary to confirm these units and their extent. A vertically exaggerated cross section showing these stratigraphic units is presented in Figure 6.33. This section corresponds with the true section shown in Figure 6.31. These stratigraphic units are discussed below with a detailed stratigraphic column presented in Figure 6.32. Table 6.7 provides a summary of the unit's thickness, type, occurrence, and permeability. - Unit K An alluvial deposit, designated as Unit K, is the oldest and deepest Quarternary deposit found in the relict chan- nel area. This unit was only encountered in one borehole at a depth of 292 feet (DR-22). The unit, which is 162 RCRf� e =a feet thick overlies bedrock, it is composed of boulders, cobbles, and gravels. Increasing amounts of fine materi- al are present in the upper horizons of the unit. Unit K appears to be an extremely dense alluvium that was de- posited within the main thalweg of the relics: channel, prior to glaciation. No other evidence of this unit was found in the relict channel area. - Unit J A dense till, designated as Unit J, is the oldest glacial deposit in the relict channel area. This till generally overlies bedrock, except in the thalweg of the relict channel, where it overlies the older alluvium of Unit K. This till is distinguished by poorly sorted subangular silts, sands,.gravels, and cobbles which are highly com- pacted as a result of being overridden by later ice advances. Hematite and limonite staining is common in the unit. The unit appears to follow the topography of the underlying bedrock surface reaching its maximum thickness in the relict channel of approximately 60 feet (Figure 6.33). - Unit J' Unit J' is a localized clean sand and gravel fluvial deposit that is up to 45 feet thick. The unit is distin- guished by its clean, sorted, rounded particles and high permeability. Water losses in excess of 50 gallon/feet were noted during drilling of this unit. This unit, which likely represents an interglacial outwash and allu- vium, is found only in the relict channel thalweg. - Unit I Another till, designated Unit I, overlies Units J and P . This till, is very similar in texture, composition, den- sity, and color with the underlying Unit J, making dis- tinction between the units difficult. The only noted difference is that Unit J is marked by a 2-to-6-inch layer of sand or silt within the middle of the unit. The average thickness of this unit where drilled is 60 feet. - Unit H Unit H is a series of alluvial and represent a period of interglacial which is found as channel deposits Borrow Site D, becomes thicker and buried channel. Unit H likely repr ly discontinuous remnants of an 6-35 outwash deposits which melting. This unit, in topographic lows of more continuous in the esents the horizontal- outwash plain cut by ACRlS alluvial channels. Thickness of the unit in the channel reaches a maximum of 40 feet. Particles are generally sorted and sub -rounded to rounded gravels and sands, which are moderately permeable (Figure 6.33). - Unit G Unit G marks another glacial advance. This unit contains greater amounts of fine material than the other units. In some areas, the material is plastic, containing a large portion of clay size particles with varied lacus- trine deposits. Gravel and sand usually are present, often with ice -rafted cobbles and boulders. Such materi- al is typical of tills deposited by either floating ice or in water that is in contact with the ice margin. Other areas have rounded to sub -angular poorly sorted silt, sand, gravel, and cobbles, which are typical of basal glacial tills. Unit G reaches a maximum thickness of 65 feet. - Units C, E, and F A final retreat of the ice in this area is marked by lay- ers of outwash, designated units C, E, and F. These units, which are similar to each other, contain varying amounts of partially sorted and rounded cobbles, gravels, sands, and silts. These units can be distinguished prin- cipally through their stratigraphic position. Permeabil- ity of these units is generally low to moderate, because of the presence of varying amounts of fines. Since these units were deposited as glacial outwash, they tend to fill in topographic lows and smooth the topography. The upper horizon of the outwash, Unit C, is often absent, possibly having been removed by post -glacial erosion in many areas. Thickness of the outwash in the buried chan- nel area reaches a maximum of 75 feet. - Unit D Unit D occurs locally as well -sorted alluvial, sands, silts, and gravels between outwash C and E. This materi- al in fills channels cut into the outwash surface of Unit E. These channels generally trend southward across the area, toward the present Susitna River. The thickness of these channels is approximately 15 feet. RCNES 6.36 - Units A and B Near surface deposits confined to the upper few feet of Unit D are mainly cobbles raised by frost action and or- ganic tundra material (Unit A) in a silty sand matrix (Unit B). These two units are not present in significant thickness and, therefore, have not been shown on the sec- tions. Based on the stratigraphy presented above, it appears that the relict channel has been overrun by a minimum of two and possibly three glacial advances (Units J, I, and C). Interglacial periods are marked by varying thick- nesses of glaciofluvial and paraglacial silts, sands, and gravels with occasional cobbles (Units J', N, C, E, F, D, A, and B). This glacial sequence indicates that Units I through K have been overridden and consolidated by subsequent glac- ial readvances. (v) Groundwater The groundwater regime in the relict channel is complex because of the presence of intermittent permafrost, aqui- cludes, perched water tables, and confined aquifers. There are insufficient data to fully document the groundwater conditions in this area; however, the following presents what is currently known regarding the regime. Further detailed investigations will be required to accurately determine the number, extent, flow directions, and perme- abilities within the various aquifers. The relict channel lies within the drainage between Deadman Creek to the east, the Susitna River to the south, and Tsusena Creek to the west and northwest. Groundwater grad- ients in the unconsolidated sediments of the channel are principally towards Tsusena and Deadman Creeks with the diorite pluton at the damsite acting as a groundwater bar- rier to the south. Most of the test pits and auger holes drilled and excavated in the relict channel and Borrow Site D (Section 6.3) en- countered water within the upper 10 feet. Those holes that did not encounter water were either in solid frost or in the coarser permeable gravels of Units C through F. The near surface water table appears to be perched on top of the impervious or semipervious Unit G. Therefore, this shallow water table likely reflects the upper seasonal thaw surface overlying this unit. 6-37 RCNIS Artesian conditions were encountered in Unit H suggesting that it is being confined below the low permeable Unit G. Highly permeable zones were encountered in Units J' and K at depths of 208 to 231 feet and 293 to 375 feet, respec- tively (DR-22) (Figure 5.1). In summary, the principal water bearing units within the relict channel appear to be in Units C, D, H, J', and K. The actual permeabilities of these units, however, have not been determined. (vi) Permafrost Intermittent permafrost in the relict channel area is evi- dent by localized frost -heave features, cobble paving and isolated spruce cover. The extent of permafrost within the relict channel and Bor- row Site D has been determined by drilling records and thermistor instrumentation installed in various boreholes drilled by the COE and Acres (Tables 3.2 and 5.4 and Figure 5.1). Thermistor readings are presented in Figure 6.28. Drilling performed by the COE showed only sporadic perma- frost in the relict channel area. Borings AP-1 and 2, DR-16 through DR-20 and DR-22 did not show excess amounts of permafrost; whereas borings DR-18 and DR-22 encountered permafrost in Units G and H at depths of 20 to 68 feet and 72 to 110 feet, respectively (Figure 6.33). Thermistor data in these holes show freezing temperatures from approx- imately 60 to 140 feet below ground surface in both holes. Permafrost was encountered in 28 of the 44 auger holes drilled in Borrow Site D. Many of these holes showed sea- sonal frost from near ground surface to approximate depth of 7 feet, with permafrost being encountered from around 12 to 20 feet. However, several holes showed continuous frost/permafrost to the full depth drilled (Appendix F). No visual ice or excess water (upon thawing) was found within any of the drilled holes below 25 feet. This lack of free ice below 25 feet is supported by the moisture con- tents of this material, which is near optimum (12 to 14 percent (Section 6.3[d]). The deepest permafrost encounted in the relict channel was at a depth of 240 feet in DR-22 (Figure 5.1). However, the deepest continuous permafrost was about 30 to 40 feet. !ACRES 6 =A The temperatures in the relict channel are fairly uniform with temperatures in the thalweg segment of the channel being close to 1°C. Slightly higher temperatures were mea- sured in DR-22 in the more permeable units of H and V dur- ing the initial reading (Figure 6.28). This likely reflects an unstable temperature condition caused by drill- ing fluid that was injected into this zone. Temperature readings in Borrow Site D (Figure 6.28) show temperatures near 1 to 2°C, suggesting a marginal perma- frost condition. However, most of these thermistors were installed in the summer/fall of 1981 and, as is common in "warm" permafrost, they have not fully stabilized over such a short time period. Future readings will likely show a shift towards cooler temperatures. (b) Fog Lakes "Relict" Channel (i ) Introduction Other areas around the damsite and within the reservoir were investigated during the 1980-81 program to determine whether other buried channels existed that could potential- ly affect reservoir impoundment. A complete review of site and regional geologic mapping, reservoir mapping, and airphoto interpretation showed that the only potential buried channel(s) which might be inun- dated by the Watana Reservoir (other than the Watana Relict Channel (Section 6.2 [a]) is in the area between (quarry Site A immediately upstream from the damsite and Fog Lakes approximately five miles to the east. In 1981, a 24,000-foot seismic refraction line was run in this area to determine the top -of -rock. Details of this survey are presented in Appendix I. The following sections briefly summarize the results of that survey and the poten- tial impacts of this area to the project. Location and Confi uration The location of the seismic line performed in this area is shown in Figure 1 - Appendix 1. The minimum surface elevation along the line is approxi- mately 2280 feet, nearly 80 feet above Maximum Pool Eleva- tion of 2202 feet. For discussion, the bedrock surface, as shown along the seismic lines, can be divided into 3 sections: the west section, central section, and east section. s-39 ACNES The west section of the line extends from the rock outcrop south of Quarry Site A eastward along the line for approxi- mately 2,000 feet. Here, the bedrock surface appears to be a series of ridges and valleys with the deepest bedrock reaching Elevation 2025 or 175 below maximum pool level. The central section continues for approximately 2 miles easterly. Bedrock in this area is relatively shallow and generally flat to slightly undulating. Along the western portion of the line in the Fog Lakes area, bedrock drops off rapidly to depths up to 350 feet until it again shallows along the east edge of the line. The total estimated width of bedrock below maximum pool level along this line is estimated to be about 2,400 feet along the west section near Quarry Site A and 7,100 feet along the east section in the Fog Lakes area. (iii) Geology Since no subsurface drilling was performed in this area, soil and rock types and depths to bedrock have been in- ferred based solely on seismic velocity measurements. Woodward -Clyde Consultants delineated three general types of soils in this area: (a) a poorly consolidated, satur- ated glacial deposit; (b) a well -consolidated glacial sedi- ment which may be partially frozen; and (c) an intermittent surficial material ranging up to 50 feet thick. Several areas along the traverse appear to be buried chan- nels which extend below the proposed reservoir level. The two most prominent areas are near the west end of the tra- verse and beneath the Fog Lakes Valley (Figures 17, 22, 23 of Appendix 1). The shape of the channel shown on the profile has been con- servatively estimated based on marginal arrival time data from distant offsets and from minimum depth calculations. A number of urtcOrtlin-t.ies exist in the interpretation, par- tir_.ularly tho nat'uro of the 8,000 to '11,000 fps apparent channel fill material. This material could bu either per- mafrost, ov-rcon o:idreed till, or aeathered rock. Future i nvesti gdti ons in this area may be warranted to determine the nature of this material and the ar .ual existence of a buried valley, RCRISI e^^ (iv) Groundwater The groundwater table in the area appears to be relatively shallow, as evidenced by poor surface drainage and numerous ponds, lakes, and bogs. Drainage of the area is toward the Susitna to the north and Fog Creek, nearly 5 miles, to the south. Groundwater gradients are expected to be steep in the Susitna drainage area and very low (<1 percent) toward Fog Creek. (v) Permafrost Permafrost conditions are likely to be sporadic throughout the area, as evidenced by the existence of typical perma- frost features to include black spruce, hummocky tundra, perched ponds on hills, and skin flows. 6.3 - Borrow and Quarry Material The borrow and quarry materials investigation at Watana was directed to: - further investigate the quantity and material properties of borrow and quarry sources identified in previous studies, and - locate new potential source areas for those materials considered to have either insufficient reserves or questionable production feasi- bility. A total of seven borrow sites and three quarry sites have been identi- fied for dam construction material (A, B, C, D, E, F, H, I, J, and L) (Figure 6.36). Of these, Borrow Sites D and H are considered as poten- tial sources for semipervious to pervious material; Sites C, E, and F for granular material; Sites I and J for pervious gravel; and Quarry Sites A, B, and L for rock fill. Several of these sites (B, C, and F), previously identified by the COE, were not considered as primary sites for this study because: (1) a more locally available source of material to the damsite; (2) adverse environmental impacts; (3) insufficient quantity; or (4) poor quality of the material. Therefore, no work was performed in these areas dur- ing 1980-81. These sites, however, have not been totally eliminated from consideration as alternative sources and are therefore included in this discussion. Since adequate quality and quantity of quarry rock are readily avail- able adjacent to the damsites, the quarry investigation was principally limited to general field reconnaissance to delineate boundaries of the quarry sites and to determine approximate reserve capacity. This al- lowed for a more detailed investigation in the borrow sites. 41 lacy The borrow investigations consisted of seismic refraction surveys, test ? pits, auger holes, instrumentation, and laboratory testing. The re- sults of this study are discussed below. Each site is presented in the following sequence: (i) Proposed use of the material and why the site was selected; (ii) Location and geology, including topography, geomorphology, vege- tation, climatic data, groundwater, permafrost, and strati- graphy ; (iii) Reserves, lithology, and zonation; and (iv) Engineering properties which include index properties and labor- atory test results. (a) Quarry Site A (i) Proposed Use Quarry Site A is a large exposed diorite and andesite por- phyry rock knob at the south abutment of the Watana damsite (Figure 6.35). The predominant rock type is diorite. The proposed use for the quarry is for blasted rockfill and riprap. Quarry Site A was selected based on its apparent good rock quality and close proximity to the damsite. (ii) Location and Geology The boundaries of Quarry Site A include the bedrock "knob" from approximate Elevation 2300 to about 2600 (Figure 6.37). The knob covers an area approximately one square mile. Glacial scouring has gouged out east -west swales in the rock (Figure 6.37). These swales likely corresponded with fractured, sheared, and altered zones within the rock body. Overburden ranges from 0 to several feet over the site. Vegetation is limited to scrubby spruce, vines, and tundra, with limited alder growth in the lower areas. Sur- face water is evident only in isolated deeper swales. Based on information presented in Section 6.1(g), the groundwater table is expected to be deep in this area with an estimated average depth to the water table from 50 to 100 feet. It is likely that the groundwater level will be near the quarry floor during operation, but inflows are expected to be small, diminishing with time. RCRf� e a= Although no borings have been drilled in this site, it is likely that permafrost will be encountered as shallow as 5 feet in depth. The permafrost, however, is near the thaw point (see Section 6.2[h]) and, because of the high expo- sure to sunlight in this area, is expected to dissipate rapidly. The permafrost zones are expected to be more com- mon in the more fractured and sheared zones. The western portion of the site has been mapped as sheared andesite porphyry (Figure 6.37) with the remainder of the site being gray diorite. Mapping on the northern half of the site in 1980-81 showed the rock to grade between black andesite porphyry and a coarse -grained gray andesite with sections grading into diorite. Despite these lithologic variations, the rock body is relatively homogeneous. Based on airphoto interpretation, severe shearing and alteration appear to be present on the northeast corner of the deline- ated site area. (iii) Reserves The limits denoted in Figure 6.37 are conservatively drawn to include all exposed or partially covered rock which com- prises approximately 530 acres. Extension of these limits would likely include areas of deeper overburden. The depth of severe weathering is estimated to be an average of 5 to 10 feet. The rock exposure in Quarry Site A provided adequate confi- dence in assessing the quality and quantity of available rockfill necessary for feasibility. Allowing for spoilage of poor quality rock caused by alteration and fracturing, and assuming a minimum bottom elevation of 2300, the esti- mated volume of sheared or weathered rock is 23 million cubic yards (mcy) and 71 mcy of good quality rock. Additional rock fill, if required, can be obtained by deep- ening the quarry to near the proposed dam crest elevation of 2210 without adversely affecting the dam foundation or integrity of the reservoir. (iv) Engineering Properties Weathering and freeze -thaw tests were conducted to deter- mine the rock's resistance to severe environmental condi- tions. Results indicate that the rock is very resistant to abrasion and mechanical breakdown, seldom losing strength or durability in presence of water and demonstrating high resistance to breakdown by freeze -thaw. Since this rock is of the same parent rock as the damsite, its physical and mechanical properties are expected to be similar to those results presented in Section 6.1(e). The rock is expected to make excellent riprap, rock shell, or road foundation material. (b) Quarry Site B (i) Proposed Use Quarry Site B was identified in previous investigations as a potential rock quarry for dam construction (Figure 6.36 and 6.38). The area was identified based on outcrops ex- posed between Elevations 1700 and 2000 along the Susitna River and Deadman Creek. During 1980-81 field reconnais- sance, mapping and additional seismic refraction surveys were performed in this area. (ii) Location and Geology Quarry Site B is located about two miles upstream from the damsite between Elevations 1700 and 2000. This area ini- tially appeared economically attractive because of the short -haul distance and low -haul gradient to the damsite. However, geologic mapping and seismic refraction surveys performed in this area indicate that the rock is inter - fingered with poor quality sedimentary volcanic and meta- morphic rocks (Figure 6.38) with thick overburden in sev- eral areas (Appendices H and I). Vegetation cover is heavy, consisting of dense alder marshes and alder with aspen and black spruce in the higher, drier areas. The entire south -facing side of the site is wet and marshy with numerous permafrost features. The quarry side facing Deadman Creek is dry, with thick till overburden, which appears frozen. Permafrost in the area is expected to be continuous and deep. Surface runoff from Borrow Site D (Section 6.3 [d]) flows southward pass- ing through Quarry Site B. (iii) Reserves Because of (a) the deep overburden (as evidenced by seismic lines SL81-18 and 19); (b) generally poor rock quality; and (c) the extreme vegetation and topographic relief, Quarry Site B was not considered as a primary quarry site. There- fore, no reserve quantities were determined for feasibil- ity. RCfll3 6 a< (iv) Engineering Properties No material property testing was performed for this area. (c) Borrow Site C (i) Proposed Use Borrow Site C was identified in previous studies as a pos- sible source of gravels and sands for filter material (45). Previous explorations in Borrow Site C consisted of three seismic refraction lines and one test pit (39). The 1980- 81 investigation identified adequate volumes of granular material much closer to the damsite in Borrow Site E (Sec- tion 6.3[el). Therefore, no additional work was performed in this area during this study. ( i i ) Location and Geology Borrow Site C, as delineated by the COE, extends from a point approximately 4-1/2 miles upstream from Tsusena Butte to the northwest toe of the butte (see Figure 6.39). As seen from the photo on Figure 6.39, the site is a broad glacial valley filled with till and alluvium. Vegetation ranges from alpine tundra on the valley walls to heavy brush and mixed trees at the lower elevations, thinning to mixed grass and tundra near the river and on terraces. The groundwater table is assumed to be a subdued replica of the topography, being shallow on the valley walls with grad- ients towards the valley floor. Groundwater migration is expected to be rapid through the highly permeable alluvial material. Permafrost may be intermittent. Based on the test pit and a seismic refraction survey, the stratigraphy appears to consist of over 200 feet of basal till overlain by outwash, and reworked outwash alluvium. The upper 100 to 200 feet of material is believed to be saturated gravels and sands. (iii) Reserves Because the site is not currently being considered as a borrow source, no detailed quantity estimate has been made. However, assuming an approximate area of 1,500 acres and an excavation depth of 15 feet above water table, a gravel quantity on the order of 25 mcy can be approximated. Addi- tional quantities may be obtained at depth; however, further studies will be required to determine the volumes. 6-45 La�Fsl (d) (iv) Engineering Properties The test pit and reconnaissance mapping show the material in the floodplain and terraces to be a 4-inch minus, well washed gravel with approximately 60 percent gravel, 40 per- cent sand, and negligible fines. The gradations are repre- sentative of a clean, well -washed material with a percen- tage of cobbles and fines at depth. Borrow Site D (i) Proposed Use Borrow Site D was identified in 1975 as a potential primary source for impervious and semipervious material by the COE. Based on the field studies performed by the COE in 1978 (45), it was tentatively concluded that: - Borrow Site D had potentially large quantities of clay and silt; - The deposit was of adequate volume to provide the esti- mated quantity of material needed for construction; and - The site had favorable topography and hydrology for bor- row development. As a result of these previous studies, Borrow Site D became a primary site for detailed investigation during the 1980- 81 study. (ii) Location and Geology Borrow Site D lies on a broad plateau immediately northwest of the Watana damsite. The southern edge of the site lies approximately 1/2 mile northeast of the dam limits and extends eastward towards Deadman Creek for a distance of approximately 3 miles (Figure 6.40). The topography slopes upward from the damsite elevation of 2150 northward to approximate Elevation 2450. The ground surface has localized benches and swales up to 50 feet in height. The ground surface drops off steeply at the slopes of Deadman Creek and the Susitna River. As noted in the site photographs shown in Figures 6.30 and 6.40, vegetation is predominantly tundra and sedge grass averaging about one foot thick with isolated strands of spruce trees on the higher and dryer portions of the site. RCIS � s a6 Climatic conditions are similar to those at the damsite with the exception that the borrow site is more exposed to higher winds and sunlight. The relatively open rolling topography is conductive to drifting and blowing snow, fre- quently resulting in drifts up to six feet deep. Surface water and groundwater conditions have been ad- dressed in detail in Section 6.2 - Watana Relict Channel. In summary, the northwest portion of the site has numerous lakes and shallow ponds with the remaining portions of the site having localized standing water perched on either per- mafrost or impervious soils. Surface runoff is towards Deadman Creek to the northeast and Tsusena Creek to the west. Generally, much of the area is poorly drained, with many of the low-lying areas wet and boggy. Instrumentation installed throughout the borrow site shows intermittent "warm" permafrost. Temperatures in the perma- frost zones are all within the -1°C range. Detailed dis- cussions of permafrost as it relates to specific strati - graphic units within the area have been addressed in Sec- tion 6.2. Ther mistor plots (Figure 6.28) show annual frost penetration of approximately 15 to 20 feet. Annual ampli- tude (fluctuation) in ground temperature reaches depths of 20 to 40 feet. The greatest depth of temperature amplitude is in the unfrozen holes, while the permafrost holes reach 20 to 25 feet. This may be caused by either the effect of possibly greater water content at the freezing interface lessening the seasonal energy variations or the thicker vegetation cover in the permafrost area causing better in- sulation. Detailed discussion of the borrow site geology are present- ed in Section 6.2. The distribution of the various strati - graphic units within the borrow site are shown in Figure 6.32. (iii) Reserves The boundaries of the borrow site, as shown in Figure 6.40, are somewhat arbitrary, being limited on the south side by the apparent limit of undisturbed material, to the east by Deadman Creek; to the northwest by low topography; and to the north by shallowing bedrock. If further studies indi- cate the need for additional materials, it may be feasible to extend the borrow site to the northwest and west. Fac- tors to be considered in borrow site expansion are: s a, RCBf� Siting of other facilities in this area; Impacts on relict channel; - Haul distance; and - Environmental impacts. The reserve estimates for Borrow Site D have assumed an average material thickness throughout the site limits (Figure 6.40). Based on the currently established boundar- ies (encompassing about 1,075 acres) and an excavation depth of 120 feet, a total of 200 mcy of material is avail- able. (iv) Engineering Pro erties The laboratory tests performed on materials from Borrow Site D are presented in Appendix F. A tabulation of the samples collected and the test results are presented in Table 6.8. Grain size distribution within the borrow site ranges from coarse gravels to clay, as shown in the composite grain size curves (Figure 6.41). Groupings of the various soil types are shown in Figure 6.42. Soil gradations, as relat- ed to the stratigraphic units within the borrow site (Sec- tion 6.2), are shown in Table 6.9. As can be seen in Figure 6.41, almost all of these samples are well graded, ranging from gravel to fine silt and/or clay. Only Unit H (Section 6.2) exhibits a different characteristic, being a more uniform fine sand and silt. Moisture contents range from a low of 6 percent to a high of 42.5 percent with an average of approximately 14 percent. The highest moisture contents are found in Unit G, a fine gray clayey material (Section 6.2). Atterberg limits show the soil to fall into two basic groups. The first, consisting of Units C, D, E, and F, are basically non or slightly plastic material. The Liquid Limits of these soils are close to their natural moisture content, varying from 13 to 17 percent. These tests are consistent with previous tests by the COE which show the material to be non plastic or slightly plastic in nature. The plasticity index varies from non plastic (NP) to 2. The second group, comprising soil units G, I, and J, have liquid limits ranging from 17 to 39 percent with plasticity indices ranging from NP to 15 with an average of 10. Specific gravity for the material is 2.71, which is within an expected range for these soils. Permeability tests on samples compacted to Modified and Standard Proctor values at 2 percent above optimum moisture content gave permeabil- ities on the order of 10- cm/sec. lA�isl 6<e Compaction of a composite sample from Borrow Site D was undertaken utilizing both Standard and Modified Proctor Compaction procedures. The Standard Proctor Test (material <No. 4 sieve) shows the material to have a maximum dry den- sity of about 128 pcf at an optimum moisture content of 10.4 percent. Modified Proctor Test results (material 0/4 inch sieve) indicate a maximum dry density of 135 pcf at 7.5 percent moisture. Modified and Standard Proctor compaction at 2 percent above optimum moisture content give consolidation compressive indices (Cc) of 0.061 and 0.091, respectively. Shear strength tests give an angle of internal friction (�) of 37 degrees, which corresponds with previous COE data. Pinhole dispersion tests indicated the material to be non - dispersive. (e) Borrow Site E (i) Proposed Use Borrow Site E (Figures 6.43 and 6.36) was identified by the COE as a principal source of concrete aggregate and filter material for the Watana dam. The apparent volume of mater- ial and its close proximity to the site made it the primary site for detailed investigations during the 1980-81 pro- gram. (ii) Location and Geology Borrow Site E is located three miles downstream from the damsite on the north bank at the confluence of Tsusena Creek and the Susitna River (Figure 6.43). The site is a large flat alluvial fan deposit which extends for 12,000 feet east -,rest and approximately 2,000 feet northward from the Susitna River up Tsusena Creek. Elevation across the site varies from a low of 1410 near river level to 1700 where the alluvial and terrace materials lap against the valley walls to the north (Figure 6.43). The area is vegetated by dense spruce and some alders, tun- dra, and isolated brush. Vegetation cover averages about one foot thick underlain by up to four feet of fine silts and volcanic ash. Groundwater was found to be generally greater than 10 feet deep. Groundwater levels fluctuate up to five feet from winter to summer, indicating a free draining material. 6 as ACRES The hydrologic regime shows summer peak flows in the area reaching approximate Elevation 1435-1440 at the north of Tsusena Creek. This elevation corresponds with the limit of scoured and unvegetated river bank. The estimated 50- year flood level is approximately 1,473 feet. Figure 6.53 presents a generalized stratigraphic section through the borrow site showing the underlying bedrock overlain by a sequence of bouldery till, river and flood - plain gravels and sands. As in the case of Borrow Site D, the grain size distribution in Site E varies from boulders to fine silt and clay (Figure 6.45). Within this wide range of soil types, five distinct soil gradations (A through E) can be delineated (Figure 6.46). However, the complex depositional history and the limited exploration performed in this area does not allow for ready correlation of these soil types over the site. Generally, however, the finer silts and sands are found in the upper five feet of the deposit. As noted in the typical sections (Figures 6.43 and 6.53), several abandoned river channels of either the Tsusena Creek or the Susitna River cross cut the site. The infilling and cross cutting of these streams and rivers through the site has resulted in a complex heterogeneous mixing of the materials. Exploration indicates that, although the five principal soil types are persistent with- in the site, they vary in depth from near surface to approximately 40 to 70 feet. No permafrost has been encountered in the borrow site, pro- bably because the site has a south -facing exposure and has a continuous thawing effect caused by the flowing river. Seasonal frost, up to 3 to 6 feet deep, was observed in test pits that encountered groundwater (mid -March 1981) and up to at least 13 feet in pits on the northwest side of the site that did not intercept the groundwater table. in areas of shallow groundwater, the frost was almost exclu- sively confined to the upper shallow sand and silt layers, while dry gravels showed deeper frost penetration. Annual frost penetration may be assumed to be about 3 to 6 feet in silty or clayey soils and at least 11 feet in loose dry gravels. (iii) Reserves Quantities were calculated on the basis of known and inferred deposits above and below the current river regime. Assuming an overall surface area of approximately 750 to 800 acres, the estimated quantity of material above river elevation is 34 mcy. An additional volume of 52 mcy is available below river elevation (Figure 6.44) assuming a total maximum depth of excavation of 125 feet in the RCRfS 6-50 (f) southwest corner of the borrow site, decreasing to a mini- mum of 20 feet in the northeast corner. Approximately 80 percent of the identified material in the borrow site is within the floodplain area, 10 percent in the hillside terraces, and 10 percent in the Tsusena Creek segment. Average stripping is estimated at one foot of vegetation and three to four feet of fine grained material. (iv) Engineering Properties A summary of the samples and laboratory tests performed on selected materials from Borrow Site E are shown in Table 6.10. Details of the laboratory testing are provided in Appendix F. The soil units A through E range from coarse sandy gravel through gravelly sand, silty sand, cobbles and boulders, silty sand and silt (Figure 6.46). Several of these material units correlate well with the material in Sites I and J (Sections 6.3[h]). Moisture contents for the silts range from 25 to 30 percent; sand from 4 to 15 per- cent; and gravels from 1 to 5 percent. The percentage of material over 6 inches is roughly estimated at 10 percent with the over-12-inch estimated at 5 percent. Selective mining may be possible to extract particular types of material. Further detailed investigations in this area will be required to accurately define the location and continuity of stratigraphic units. Borrow Site F (i) Proposed Use Borrow Site F was identified by the COE as a potential source of filter material for the main dam. Preliminary work performed by the COE showed the site to have limited quantities of material spread over a large area. For this reason, Borrow Site E became the preferred site, with Bor- row Site F being considered as an alternative source for construction material for access roads, runways, and camp construction. No work was performed in this area during the 1980-81 program. (ii) Location and Geology Borrow Site F occupies the middle stretch of Tsusena Creek from just above the high waterfall to north of Clark Creek where it abuts Borrow Site C (Figure 6.39). The northeast portion of the valley is confined by the flank of Tsusena (9) Butte and its talus slopes. The vegetation in the area is mixed spruce and tundra, with isolated area's of undergrowth and alders. Groundwater is expected to be near surface: Limited permafrost is likely to be encountered in north - and west -facing exposures but is expected to thaw readily When exposed during summer months. Deposits above stream level are expected to be fairly well drained with lower areas saturated. Limited test pits indicate the material in Borrow Site F is the same as that in Borrow Site C (Section 6.3 [c]). The depth of clean sands and gravels is estimated to be approx- imately 20 to 30 feet, ranging from a shallow 5 feet to a maximum of 40 feet. The area consists of a series of gravel bars and terraces extending +gyp to 1,500 feet away from the stream (Figure 6.39). (iii) Reserves No detailed topography was obtained for the site; however, assuming a conservative depth of 20 feet of material, a total volume of approximately 15 to 25 mcy is likely avail- able. Additional investigation in this area will be required to confirm these volumes. (iv) Engineering Properties Test pits excavated by the COE (Figure 6.39) show gravelly sand overlain by a very thin silt and sandy silt cover. A composite gradation curve for material in this site is shown in Figure 6.47. No detailed testing was performed on this material. Borrow Site H (i) Proposed Use Borrow Site H was defined during the 1980-81 field investi- gation as an alternative site to Borrow Site D for impervi- ous and semipervious material. (ii) Location and Geology The topography of Borrow Site H is a generally rolling, sloping towards the Susitna River. Elevations range from 1400 to 2400 across the site and average about 2100 (Figure 6.48). Most of the site is covered by swamps and marshes, indicating poor drainage. The vegetation consists of thick tundra, muskeg, alder, and underbrush growth. �ACNI� 6s= Groundwater and surface water are perched on top of imper- vious material with numerous seeps and ponded surface water, The extensive coverage of spruce trees may be indi- cative of a degrading permafrost area. A large ice deposit exists in a slump exposure on the west end of the site. The deposit and associated solifluction flow with a multi- ple regressive headwall are approximately 100 to 150 feet across and are visible in the photo (Figure 6.48). Of the eight auger holes drilled in the site, six encoun- tered permafrost at depths ranging from 0 to 14 feet in depth. All the holes but one showed the water table at or near the surface (Appendix F, Figure 6.48). All of the borings had temperature probes installed during the 1981 program; however, the instruments have not yet stabilized (Figure 6,29). Future readings are likely to show a cool- ing in the temperature plots. The site stratigraphy consists of an average of 1.5 feet of organics, underlain by 1,5 to 4,5 feet of brown sand or silt material with traces of organics. Below this upper material, most of the holes show mixed silt, sandy silt, and sandy clay to depths of 6 to 13 feet, which in turn is underlain by zones of gravels, gravelly sand, and mixed silts with sand and gravel. A color change from brown to gray occurs at depths of 6 to 28 feet. Insufficient data exist to allow for detailed stratigraphic correlation across the site. Reserves The quantity estimate has assumed a relatively homogeneous mix of material over a surface area of 800 acres,_ with 5.5 feet of stripping required to remove organics and clean silts and sands. Assuming an estimated usable thickness of 32 feet (based on drilling data) approximately 35 mcy of material is available from this site. (iv) Engineering__Propert_les A summary of the samples and laboratory test results from materials from aorrow Site H are shown on Table 6.11, Lab- oratory test results are contained in Appendix F. A composite gradation for the borrow site is shown in Figure 6,49, A detailed assessment of the grain size dis- tribution shows three distinct gradation groupings (A through C) (Figure 6,50), Gradation A denotes a gravelly sand, characterized by less than 40 percent fines and a significant fraction exceeding 3/4 inch; S is a silty sand without the generally coarser fraction; and C is a silt (h) unit which is generally less than 1 inch in maximum parti- cle size and contains in excess of 40 percent fines. The Liquid Limit of the material ranges from 17 to 34 per- cent with an average of 23 percent. Approximately one third of the samples were non plastic. Natural moisture contents ranged from 6 to 23 percent with an average of 13 percent. (one sample gave a moisture content of 53 percent but was not considered representative.) The Modified Proctor Test, conducted on 3/4-inch minus material, gave a maximum dry density of 141 pcf at 6.9 per- cent moisture. The Standard Proctor Test, at 10.8 percent moisture on the minus No. 4 material, gave a maximum dry density of 128 pcf. Permeability tests on samples compacted to Modified and Standard Proctor values at 2 percent above optimum moisture content gave permeabilities on the order of 10' cm/sec. Modified and Standard Proctor compaction at 2 percent above optimum moisture content gave a coefficient of consolida- tion (Cc) of .06 and .09, respectively. The specific gravity of the material is 2.72, which is normal for a glacial till. The undrained shear strength tests run on samples at 95 percent of Modified Proctor density and 2 percent above optimum moisture gave a friction angle of 37 degrees with cohesion of 648 psf. Pin -hole dispersion tests showed the material was not dis- persi ve. In conclusion, Borrow Site H material is considered suit- able for use as impervious and semipervious fill. However, problems such as wet swampy conditions, permafrost, and the lengthy haul distance to the site may affect the potential use of this site as a borrow source. Borrow Sites I and J (i) Proposed Use Reconnaissance mapping was performed within a 10-mile radi- us of the damsite to locate potential sources of free - draining gravels for use in the dam shell. The large vol- ume needs of this material requires that the source be rel- atively close to the damsite and in an area that would min- imize environmental impacts during borrowing operations. As a result, the Susitna River valley alluvium was deline- ated as a potential borrow source. RCI�S, s a (ii) Location and Geolog Seismic refraction survey performed across the river chan- nel during 1980-81 indicated large quantities of sands and gravel within the river and floodplain deposits both up- stream and downstream from the damsite. Borrow Site I extends from the western limits of Borrow Site E downstream for a distance of approximately 9 miles, encompassing a wide zone of terrace and floodplain deposits (Figures 6.51 and 6.53), Borrow Site J extends upstream from the damsite for a dis- tance of approximately 7.6 miles. The site area extends from river bank to river bank and includes several terraces and stream deltas (Figures 6.52 and 6.53). Borrow Sites I and J are fully within the confines of the Devil Canyon and Watana reservoirs, respectively. Both sites are in an active fluvial environment. Borrow Site J is flanked by bedrock, talus and till -covered valley walls; while Borrow Site I includes extensive terraces ex- tending several hundred feet up the valley walls above river level. (iii) Reserves For purposes of volume calculation, it was assumed that all materials with seismic velocity of 6,500 feet per second represented suitable gravel deposits (Table 6.1). Materi- als with velocities higher than 6,500 were assumed to be either too bouldery or dense. Not included in the estimate were: - The river material between the two sites; - Material between the west boundary of Site J and the downstream area of the damsite; and - The section from the damsite to Borrow Site E. This last area was considered to require excessive dredging and could likely affect the hydraulics of the tailwater. An active slope failure was identified near Borrow Site H (Appendix K). If further studies show that the excavation of river material beneath this slide may result in slope failure, than this section of alluvium will be left in place. In summary, a total of 125 mcy of material were estimated in Borrow Site I extending a distance of 8.5 miles downstream and 75 mcy in Borrow Site J over a dis- tance of 7 miles upstream. 655 IA�A�sI (iv) Engineering Properties Individual gradation curves from a total of 45 samples taken from 22 test pits are presented in Appendix F and summarized on a composite curve shown on Figure 6.54. Soil properties determined from laboratory testing are shown in Table 6.12. Three basic gradations are present within the two sites. These are fine grained silty sand, sand and gravel (Figure 6.55). The fine silty sand fraction was encountered in 25 percent of the test pits and ranged in thickness from 6 inches to 6 feet. The second gradation is a sand which varies from a well -sorted clean sand to a gravelly poorly sorted sand. This type of material was encountered in only 15 percent of the pits, and where present, underlies the silt layer with an average thickness of about 4 feet. The bulk of the samples are of a moderately sorted gravel mixed with from 20 to 40 percent of sand and silt with less than 5 percent silt and clay size fraction. No indication of plasticity in the fines was noted. (i) Quarry Site L (i) Proposed Use Quarry Site L was identified during the 1980-81 program as a source for cofferdam shell material. (ii) Location and Geology Quarry Site L is located 400 feet upstream from the pro- posed upstream cofferdam (Figure 6.56) on the south bank. The site is a rock knob immediately adjacent to the river which is separated from the main valley walls by a topo- graphically low swale that has been mapped as a relict channel (Appendix J). The rock in the quarry area is diorite along the western portion of the knob with andesitic sills or dikes found farther upstream. The rock exposure facing the river is sound with very few shears or fractures. The vegetation is heavy brush with tall deciduous trees on the knob and aldens with brush in the swale to the south. Little sur- face water is present on the knob; however, the low lying swale is marshy. Permafrost may be expected to be present throughout the rock mass. RCB66-56 Quarry Site L lies opposite "She Fins" feature which is ex- posed on the north abutment (Section 6.1[c]); however, extensive mapping in this area shows no apparent shearing or fracture that could be correlative with the extension of this feature. (iii) Reserves Because of limited bedrock control, the site has been de- lineated into two zones for estimating reserves (Figure 6.56). Zone I delimits the total potential reserves based on assumed overburden and rock volumes, while Zone II iden- tifies that volume of rock that, with a high degree of con- fidence, is known to be present (Figure 6.56). Based on field mapping and airphoto interpretation, the total use- able volume of material has been estimated to be 1.3 mcy for Zone I and 1.2 mcy for Zone II, over an area of 20 acres. (iv) Engineering Properties No testing was performed on rock samples for Quarry Site L. However, based on field mapping, it appears that the rock properties and quantities will be similar to those at the damsite (Section 6.1[d] and [el). 6-57 0-1500 1500-3900 3900-4900 4600-4600 4900-5500 5500-7000 7000-10000 10000-15000 15000-20000 20000+ TABLE 6.1: WATANA SEISMIC VELOCITY CORRELATIONS Shallow, loose dry sands, gravels, soil Moist Gravels, sands, talus, slope wash, generally well drained. Can include loose, drained tills and outwash, unfrozen clays. Moist alluvial terraces, gravels - occurs predominately as surface terraces or as shallow depth channel fill in relict channel bedrock lows above elevation 2200 - possible beaded stream deposits. Water Granular alluvium, saturated, and possible outwash; may be frozen. May represent less bouldery beds of stream alluvium and outwash. Low velocity saturated gravels, outwash. Also higher velocity active river alluvium and talus velocities. Probably includes majority of frozen alluvium and tills. Dense tills, alluvium, boulders, and coarse outwash materials. May include frozen clays and gravels. Also highly weathered sheared rock. Sheared and severely fractured and altered bedrock. Over consolidated tills and/or sedimentary rocks and frozen talus. Bedrock, velocity represents lower range, fractured and altered rock, while higher velocities are sound rock. Sound crystalline bedrock. F- 4 1 O N ro cn�a4i �t O ro @ rl c a) fJJ @ N ri 4 Il) ro ro N C 4 (D C O roL O•r' 4- a) N a-) 1 11 4 6) C cam � m O 0 O 0) N mC Nti N 5 V) O U •ri ro Z cy0 �-• 4 ; m Q Q 4 -i •N E 4 O O N O G3 N N 4J 0C N H HH 4 N C @ ro H d ILl1 N 3 3 U') I 7 -P 4- O N 3 ca N N 4-) JOi N 3 O u C U �7 ro @ O 0 µ @ r01 (0 O r1 @ H O p) (D w 0) G3 N N N c +� e- ro ro +' +' mro +� +� @ +� ro .t u @ O @ I U U (a O CO O O O ro .-I O L 0 3 A 4 04 4 O 011 -0 a .0n -0 -0H 4 •O '7 I C I 4 4 H O 4 co H co O co ca N co U•U E I U �3 f3 U L) C O I C Co T @ ro ro 00 O H H O -P (M. Q) p)L O) U Li p) O L 0) N O) 0) 14 L JL-) 4 •H -P 4 L ({�-) 7 4 ro 7 O OO 14 N 41 r1 10 4 i E O E O N U H V) 0 0 V) O 1-r 0 0 O 1+ -HH 4J -P -P -P -P O NH �L N ro� NL n O c ro 7 co -C c 0 @-P C O 0) roL C O) C U 7 c 0 C 0) ca0c roD @Oa cva ro m 4 ro p ron H O •� —1 O • 1 E O .-1 O H O 7 .-I E H p d H y IL 4 a. V) Fy IL 4 IL H U d V) 4 • cr 'k > _ N N N N N � N r• r r N c U Il Il N U1 P U1 U1 � � CY @ r CV r r r N C) z z z w w 1.! a) • O P O U1 O U1 O 0 O 0 o 0 0 m N > a, m m r- m m m �a �n m CL r1 3 z p o 3 -P O C( O @ H N Z o r e U1 O _r_ r- 00 +7 LO I 4 ro H 7 N O) 4 7 U) ••-1-1 4 O 7 00 G -P4..H -P H L C C O U EEn 'r-I IL a) -0 N N M 11% O [ E I N a- \0 Z In z In W z o o o o a a O V1p C:) UN Ul c-N �7 c-ON 0 0 P a U% P O a 0 O U1 0 U1 0 O G U1 0 0 0 0 0 0 0 0 O C:)V\ N S O \O a C)U\ d K1 N C 00 R+ 0C)M1 pie T O O O NN1 M N O C)O C) C)K% d p a) H•rl C � 8 p 4@ P 0 e O ro -P .i +� @ OI M 4 C � 7 Nel o 4 O G O U N O KN CO U U1 N N WLLJO cnn z z z +� z z z z ° 4 z ¢ cLn ran ran cn H H H H f-e H w C T N C N p 4 Cl @ m .�q m a) U IA ro cF4 C 4 C 7 L TABLE 6.3: WATANA RQD SUMMARY Borehole DH--1* DH-4 DH-5* DH-6* DH-7* DH-8* DH-9* DH-10 DH-11 DH-12 DH-21 DH-23 DH-24 DH-28 BH-1 BH-2 BH-3 BH-4 BH-6 BH-8 BH-12 Total Rocl Ground Surface El. (Feet) 1459 1462 1462 1716 1716 1910 1913 2033 2034 1951 1480 1952 2061 1971 2050 1835 2150 2185 1605 1976 1966 Drilled - Top Of Rock El. (feet) 1415 1384 1402 1713 1708 1894 1909 2020 2018 1942 1407 1947 2054 1958 2032 1826 2123 2174 1598 1964 1949 Average Borehole Di *-* V V V V 590 V 450 V 450 V 60a 450 V V 700 380 550 590 600 600 400 RQD Vertical Depth (ft) RQD Rock Drilled 0'-50' (ft) 51.4 45.2 47.9 48.9 49.1 54.5 67.0 48.6 70.3 51.6 59.7 70.5 50.9 29.5 52.5 61.2 59.1 56.9 58.5 59.2 81.5 1174. D RQD o 2890 66% 460% 501% 48 u 59% 59% 21IOU' 71 0 6000 85 0 4590' 700% 360% 79% 55°o 75,0 °' 44.0 5090 °' 43.0 57% °' 56,0 50' -150' " 27.6 69.2 97.2 64.6 79.3 139.5 100.5 144.1 99.9 110.0 41.7 82.1 62.4 104.8 119.8 124.9 115.7 118.4 116.2 151. 7 1969.6 45% 830 51 o 60 0 67an' 62°0 6890 77 0 53 u 85% 49-0 700 10°0 76°o 23% 96% 54 o 6490 750,o 72% 65 0 150'-250' " 72.1 34.8 65.0 105.1 121.7 109.6 124.4 120.0 120.8 115.8 114.5 154.0 1257.8 4400 890 85 o 77010 83°0 86 o 54% 991a, 94°0 8690 8240 6890 79 0 250'-350' 33.9 118.3 14.3 85.6 119.9 114.9 115.3 114.6 156.1 872.9 85 0 8290 73°0 75% 8700' 991-0 8100, 7900' 620 800 350'-450' " 109.5 119.5 115.1 114.4 114.3 159.3 732.1 91 0 460 9910 82 840% 79 0 7900' 450'-550' " 120.6 120.0 115.2 117.8 69.3 542.9 96% 790 710 810 830 820 550'-650' 125.0 115.1 94.8 102.0 436.9 96 0 700 79 0 88% 830 650' --750' " 120.0 114. 7 234. 7 96o 74% 860 750'-850 " 15.0 64.0 79.0 10090, 95:a 9b°0 Total Hole Length (feet) 79.0 45.2 117.1 146.1 113.7 133.8 278.6 183.9 279.4 290.5 519.2 112.2 133.0 91.9 281.2 391.0 924.0 937.2 732.4 738.6 771.9 7299.9 Average RQD 3490 66°0 68 0 500 550-1 640 5790 60 0 7890 670 84 0 47% 70% 1 B°0 BO a 49 0 96% 800% 75 o 78% 70% 72% *COE boreholes **V = vertical TABLE 6.4: WATANA - BOREHOLE ROCK QUALITY DISTRIBUTION Rock P RCE TAGE OF CORE I S ulrju RQuRANGES Drilled Borehole (ft) 0-25% 25-50% 50-75% 75-90A 90-95% 95-10O% DH-1* 79.0 29 56 8 0 7 0 DH-4* 45.2 16 5 17 52 10 0 DH-5* 117.1 6 15 31 23 3 22 DH-6* 146.1 13 30 44 9 0 4 DH-7* 113.7 13 26 29 29 0 3 DH-8* 133.8 6 11 41 32 8 2 DH-9* 278.6 19 18 25 30 7 1 DH-10* 183.9 25 12 14 23 10 16 DH-11* 279.4 3 5 22 38 17 15 DH-12* 290.5 8 17 29 17 12 17 DH-21* 519.2 0 2 25 22 14 37 DH-23* 112.2 36 22 18 8 9 7 DH--24* 133.0 5 14 42 18 9 12 DH-28* 91.9 61 29 10 0 0 0 BH-1 281.2 2 4 22 26 18 28 BH-2 391.0 24 17 30 19 5 5 BH-3 924.0 7 2 5 12 8 66 BH-4 937.2 6 11 13 9 7 54 BH-6 732.4 5 7 22 33 15 18 BH-8 730.6 3 6 22 30 11 28 BB-12 771.9 6 17 30 19 10 18 Total Rack Drilled 7299.9 *COE core was relogged from boxes. TABLE 6.5: WATANA ROCK TEST SUMMARY DIORITE, QUARTZ -DIORITE, GRANODIORITE Compressive Unit Tensile Borehole Strength Weight Strength Borehole* Sample Depth (ft) (psi) (pcf) (psi) Other** BH-1 W-1-41.6 41.6 W-1-44.2 44.2 W-1-83.9 83.9 W-1-134.9 134.9 W-1-230.3 230.3 BH-2 10-80 313.8 BH-3 W-3-57.9 57.9 W--3-199.6 199.6 W-3-320.7 320.7 W-3-602.2 602.2 W-3-954.8 954.8 13H-4 W-4-90.4 90.4 W-4-285.8 285.8 W-4-533.4 533.4 W-4-535.8 535.8 W--4-690.9 690.8 W-4-888.1 888.1 BH-6 80-12 81.65 80-14 144.6 80-15 218.1 80-16 233.0 80--19 260.7 BH-8 80-28 316.9 60-29 322.6 80-31 327.46 80-35 468.4 80--38 480.65 BH-12 W-12-328.8 328.8 W-12-465.4 465.4 W-12-657.6 657.6 Average (Acres) DH-B*** 27 44.2 28 70.7 DH-10 29 70.2 30 176.5 DH-11 31 40.15 32 84.3 Average (All Tests) 23,587 23,587 24,400 17,487 10,623 19,632 20,333 4,473 11,556 12,607 14,233 15,665 14,414 7,650 14,640 21,147 15,860 15,047 16,858 28,020 26,996 21,160 23,358 19,113 18,707 13,827 17,500 +5,754 SD 21,450 29,530 20,500 18,470 10,420 7,610 17,593 +6,080 SD *Locations shown on Figure 5.1 **ED = Dynamic modulue ***CBE testing ET = Tangent modulus at 500 of Failure stress v = Poissons Ratio SD = Standard deviation 167.2 167.7 169.2 168.9 169.6 165.6 169.3 169.2 151.0 165.9 165.3 171.9 170.9 169.1 168.5 168.8 166.2 166.4 167.3 167.2 164.8 168.3 168.3 167.3 167.1 167.0 165.7 168.6 164.3 167.1 2,019 1,824 602 1,965 1,872 2,098 2,417 2,450 1,906 +576 SD ED = 10.6 x 106 psi, v = 0.29 ET - 10.6 x 106 psi, v = 0.27 Altered, unit wt. For tensile strength test = 160.5 ET = 9.9 x 106 psi, v = 0.24 Slightly altered ED = 9.4 x 106 psi, v = 0.33 ET ET = 11.2 x 106 = 9.49 psi, v = 0.24 x 106 psi, v = 0.20 ET = 8.60 x 106 psi, v = 0.22 ET = 9.41 x 106 psi, v = 0.23 ET = 9.65 x 106 psi, v = 0.27 ET..= 7.13 x 106 psi, v = 0.20 TABLE 6.6: WATANA ROCK TEST SUMMARY - ANDESITE PORPHYRY omp-re ssIve Unit si e Depth Strength Weight Streng4th Borehole* Sample (feet) (psi) ( cf) ( si} Other** BH-2 1-80 20.5 26,206 165.4 2-80 27.05 20,333 166.9 3--80 45.3 17,283 166.6 4-80 49.4 15,453 166.4 5-80 82.25 162.8 1,718 6-80 87.0 165.3 1,715 BH-4 W-4-14.2 14.2 23,180 165.4 BH-8 80-22 37.8 19,520 162.6 1,616 BH--12 W-12-41.1 41.4 18,814 163.7 BH-12 W-12-96.8 96.8 6,100 162.7 Average 18,361 164.8 1,683 +5,978 SD +58 SD *Locations shown on Figure 5.1 **ET = Tangent modulus at 50% of failure stress v = Poissons Ratio SD = Standard deviation ET = 9.9 x 106 psi, v = 0.24 ET = 10.5 x 106 psi, v = 0.27 m 1li o w d x 0.) y) N 0 w v a 'o a a v a of of (L S J J J J S .J S V c U) O -ri Ga d] H U 47 Ol E 47 c s ro E H m 4-3 a -+ CL ro v m ti 1 0 N 0) N Ol N= X !V Cri 1 N W Ql C W C rO{ N LE-1 N +� (a C N N 0 O L 7 N Cli 7 >, 7 >. 0_ 4- N o 47 UC t O -q 0 -q m 7 � U 0 ,i ctl C O C O -x �H • N '•t • H 7 +W i .-I Ol 41 .-I 4-)rl _0 U)O c 41 m m C m c m U U > N C U c ••i c c N O N•H N m m m m -6'00 U LL) c Q O U)-q 0 -4 .- w Ur -I -qr1 7 .--1 _q 14 47 m C U k m 10 is 1-1 r-I c m C H N •H -L Gl 0 4a N k N 7 m al C c N m 41 G] •r1 5 47 .r1 N •H U U 41 O m C Cp N k 4 c F, c f-I �a) C) 'J C) L7 (0 U V CO 4- U Co U Co 3 .--I 'C1 .-I N r Gl N m 4 N •�r1 -0 .--I N U Hpp N 0 (A T.N C L o)-w N Q N .al 4Na U •O -1 'ri 0 L m O '00 U U O pnp 7 m N � (a H d 67 U N Li w U X > O Ul 4a U .--I C m r-1 L .--I L 'OC v Ql O JJ Ul > C 4-)Gl m 7 L L m m 4- m m Sfl 41 F. N O aQf v U) -0 .,1 •r0 i C � o 0 Cl 41 X 3 47 T n N .-I 'O 0 .-I •O n 41 N .41 G7 N —W L [ H N W c --1C •H O m N .--I N.Q c b� N F, c U rl N (� N N N rn0 Uml 'r1 •rUi N N ri T ?. 0 T k C +--1 >,ri .. 47 ..r1 N U my nr1 47 N m m n 41-n '04J 4-) >, 4J 41 to ti� 4.)a > m 41 rn n r-I L C m _q H m y H r-1 O C 1-1 r-1 O m C w N 0 •r1 o m k •H m r-1 C •H •H O i6 •H •H O k ,rt f C1 U Ul Ll (n Ol Ul 0_ U m (n (n a u) N Ul d L7 4- N N N NN N N N N�Q 0 w ; L 40- w 40- 40- w w 4- • 4- 4- 9.0 N W Ln Ln N O » LIN O O L r LrN �o 1- r N •H C N H O a r-1 m m N H •H cl m N E 4-)E N E •H -W L 7 ri L m ' r-1 7 U •11 N 'H m N # •H 0) 'H •ri N m > •H (0 \ > Fa > .(.3 4- 0 T. 7> 3 ri r1 7 .--I N r1 •H W a N r C 7 +l r1 ri ri -1 N ri ri C 7 N 7 -4 r-I �) ri •H r-I ri C rl ri Ul Cl O 4 La O F- Q V C1 W L7 S N r7 +'7 Y TABLE 6.8: MATERIAL PROPERTIES - BORROW SITE D Hole * Trench Number Sample Number Depth (feet) Lab. Classi- fication Mechanical Anal s's Atterberg Lim'ts Specific Gravity W% From To Gravel Sand Fine I AH-DI 1 0 1.5 2 1.5 3.0 3 3.0 3.5 4 4.5 4.75 5 6.0 6.75 SM 10 48 42 NV NP 11.1 6 8.0 6.75 SM 24 22 54 6.7 7 10.0 10.75 SM 13 51 36 6.6 8 15.0 15.75 AH-D2 3 1.5 2.5 SM 33 38 28 NV NP 25.7 4 3.0 3.75 SM 24 41 35 13.9 NP 11.4 5 4.5 5.25 SM 23 46 31 NV NP 11.2 6 6.5 7.0 7 8.5 9.0 a 15.0 15.75 SC 7 49 44 15.5 2.2 11.3 9 20.0 20.75 SM-SC 15 46 39 17.5 4.2 9.4 10 25.0 25.5 AH-D3 2 .5 .75 3 1.5 2.0 4 3.0 4.0 5 4.5 5.25 6 6.5 7.25 7 8.5 9.5 8 15.0 15.75 9 20.0 20.25 10 25.0 25.25 11 30.0 30.5 AH-D4 3 1.5 3.0 5 4.5 5.0 6 6.0 7.5 8 7.5 8.0 AH-D5 3 3.0 3.75 4 7.5 9.0 SM 0 88 22 5 10.0 11.0 SM 34 47 19 6 15.0 16.5 S14 25 52 23 7 20.0 21.0 8 25.0 25.75 9 30.0 31.5 SM 0 75 25 14 NP 13 10 35.0 36.0 CL-ML 0 55 45 17 14 12 11 40.0 41.25 CL 6 42 50 23 14 12 12 45.0 46.0 SM--SC 11 64 25 39 14 9 13 48.0 48.25 AH-D6 1 0.0 2.0 3 5.0 6.0 SM 10 50 40 15 NP 10 4 6.5 7.5 SM 8 5 7.5 8.0 6 8.0 9.0 SM 0 76 24 13 NP 12 7 9.5 10.0 SM 11 8 15.0 16.0 9 20.0 21.5 SP-SC 0 88 12 17 2 12 10 25.0 26.5 SM 29 38 33 15 NP 9 11 30.0 30.5 8 12 35.0 36.0 SM 10 50 40 17 NP 9 13 40.0 40.6 12 14 45.0 46.0 AH-D7 3 5.0 5.5 11 4 7.0 8.0 SM 20 50 30 12 5 8.5 9.5 SM 11 6 15.0 16.5 SM 20 53 27 10 7 20.0 20.25 6 8 25.0 25.75 SM 6 71 23 9 9 35.0 35.25 9 10 40.0 40.75 SM 0 80 20 9 11 48.0 48.25 TABLE 6.8 (Cont'd) ole Trehch Number Sampple NUmber Depth (Feet) Lab. Claasi- ficatian Miji2hz1hicalA Ahal s a tes L "iia erg 5poblfie Gtovi A roM 10. Gi-avel SAW F, he LL PI.. AH-DB 4 5 3.5 4.5 4.5 6.0 5M 18 65 17 14 NP 15 6 6.0 6.5 7 8.0 9.5 8 9.5 11.0 SM 0 58 42 14 NP 14 9 15.0 16.5 SM 12 71 17 13 10 11 20.0 25.0 20.5 25.5 SP 28 61 11 18 5 10 13 35.0 36.0 ML 10 37 53 13 15 45.0 45.25 9 16 50.0 50.25 9 55 36 7 AH-D9 1 0.0 1.0 2 1.5 2.5 SM 10 55 35 3 3.0 4.0 SM 10 50 40 4 4.5 6.0 SM 0 60 40 5 6.0 7.5 SM 14 65 21 6 7.5 8.5 SM 0 76 23 7 9.0 10.5 SM 15 63 22 B 15.0 15.5 9 20.0 20.5 10 25.0 25.9 11 30.0 30.5 12 35.0 35.4 13 40.0 41.0 C-ML 0 8 92 21 NP 21 14 45.0 46.5 ML 0 17 83 35 8 25 15 50.0 51.5 16 55.0 55.2 17 60.0 60.25 AH-D10 1 0.0 1.0 2 1.0 1.5 3 2.0 3.0 4 3.0 3.5 5 4.0 4.5 6 5.0 5.5 7 6.0 7.5 8 7.5 8.5 9 15.0 16.0 10 20.0 20.5 11 25.0 26.0 12 30.0 31.0 13 40.0 40.33 AH-D11 3 3.0 4.0 4 4.0 6.0 5 6.0 7.5 6 7.5 9.0 7 15.0 16.5 B 20.0 21.5 9 25.0 25.25 10 30.0 31.0 11 25.0 36.5 13 45.0 45.5 15 54.5 54.66 AH-D12 3 1.5 3.0 4 3.0 4.0 5 4.5 5.5 6 6.0 6.5 7 7.5 8.0 8 9.0 9.33 9 15.0 15:3 10 20.0 20.16 11 25.0 25:5 TABLE 6.8 (Cont'd) Hole * Trench Number Sample Number Da th (feet) Lab. Classi- fication Mechanical Analysis At erberg Li its Specific Gravit WA From o Gravel San Fine 1 AH--D13 1 0.0 0.5 2 0.5 1.5 3 3.0 4.0 4 4.5 6.0 5 6.0 7.5 6 7.5 9.0 7 15.0 16.25 8 20.0 20.66 9 25.0 26.5 10 30.0 31.0 11 35.0 35.5 12 38.0 40.0 13 45.0 45.5 AH-D14 2 3.0 4.0 3 6.0 7.5 4 7.5 9.0 5 9.0 10.0 6 15.0 16.5 7 20.0 20.5 W-81 D SP 0 5 95 59 23 W-81 D 15 40 45 2.71 *Locations shown on Figure 6.40 TABLE 6.9: GRADATION RESULTS - BURROW AREA D Soil Unit Coarser than No. 4 M Between No. 4 and No. 20U (%) Finer than No. 200 (A) PI Unified Soil Classification Composite Sample 15 40 45 SM Coarse 13 62 25 SM C h D Mean 5 60 35 NP SM Fine 0 49 51 ML Coarse 32 50 i8 SM E h F Mean 12 53 35 NP SM Fine 2 4B 50 SM-ML Coarse 15 57 28 SM G Mean O 45 55 10 ML Fine 0 18 B2 ML Coarse 4 75 21 SM H Mean 0 73 27 NP SM Fine O 68 32 SM Coarse 25 55 20 SM I h J Mean 15 53 32 7.5 SM Fine 5 53 42 SM PI = Plasticity Index NP = Non -plastic TABLE 6.10; MATERIAL PROPERTIES - BORROW SITE E Hole74 Trench Number. Sample Humber 0e th (feet) Lab. Classi- fication Mechanical Anal s's Atterberg Lifqits Specific Gravit W% rom To Gravel Sand Fins LL I P11 E1 1 2.5 3.0 GP -GM 53 39 8 2 7.0 7.5 GP 74 25 1 E2 1 2.5 3.0 SP 49 49 2 2 5.5 6.0 GW 77 22 1 E3 1 2.5 3.0 GW 78 21 1 2 10.5 11.0 GP 74 24 2 E4 1 3.0 3.5 GP 82 17 1 2 10.5 11.0 GP 82 17 1 E5 1 1.0 2.0 GW 83 16 1 E6 1 7.5 8.0 SM 25 62 13 E8 1 2.5 3.0 GW 76 23 1 2 6.5 7.0 SP 36 63 1 E9 1 2.5 3.0 - 0 10 90 2 4.5 5.0 SM 22 58 20 3 7.0 8.0 GM - - - E10A 1 3.5 4.0 GP 63 34 3 2 6.5 7.5 SM 0 83 17 E108 1 2.0 2.5 GW 64 34 2 E11 1 1.5 2.0 SM 0 62 38 2 5.0 5.5 GP -GM 61 31 8 E12 1 2.0 2.5 GP -GM 63 31 6 2 2.5 3.5 SM 10 52 38 3 3.5 4.5 SM 29 47 24 E14 1 1.0 2.0 SP-SM 0 95 5 2 6.0 7.0 SP 69 28 3 E15 1 3.0 3.5 GW 83 16 1 E16 1 3.0 3.5 SP 66 32 2 E17 1 0.5 1.0 0 32 68 2 3.5 4.0 SM 0 59 41 3 10.0 10.5 GP -GM 65 30 5 E18 1 0.25 0.75 GP 55 43 2 2 2.0 2.5 SM 20 52 28 3 5.0 5.5 GP 63 36 1 4 10.0 10.5 GP 71 27 2 E19 1 1.0 1.5 SM 0 66 34 2 2.5 3.0 SM 0 79 21 E20 1 1.5 2.0 SM-ML 0 47 53 2 3.0 3.5 SP 79 19 2 3 7.5 8.5 SM 19 50 31 4 11.0 11.5 SP-SM 66 28 6 E21 1 2.0 2.5 - O 30 70 2 6.5 7.0 Gm 85 11 4 AH-El 2 0.5 1.0 3 1.0 1.5 SM 0 52 48 19.6 4 2.0 2.5 ML 0 40 60 27.3 5 4.0 4.25 7 6.5 6.75 10 12.0 12.5 11 15.0 15.25 13 23.5 25.0 AH-E2 2 1.5 2.25 3 3.0 3.5 4 5.0 5.75 5 6.5 7.0 6 8.5 9.0 AH-E3 2 0.5 1.0 3 1.0 1.5 4 1.5 2.25 5 3.0 3.75 6 4.5 5.5 SP-SM 38 56 6 4.4 7 6.5 7.5 CW 60 36 4 0.7 8 8.5 9.0 9 15.0 15.5 10 16.5 17.0 TABLE 6.10 (Cont'd) o e/* Trench Number Sample Number De th (Peet) Lab. Classi- fication Mechanicalerberg Anal s's Li its Specific Gravity W% -From To Gravel SandiFine LL PI AH-E4 2 0.5 1.5 3 1.5 3.0 4 3.0 4.0 5 4.0 4.5 6 5.0 6.5 SM 2 76 22 17.6 7 6.5 7.25 8 8.0 8.75 AH-E5 2 1.0 1.5 3 1.5 2.0 4 2.0 2.5 6 4.0 5.25 8 6.0 6.75 10 7.5 8.5 11 9.0 10.25 AM-E6 2 0.5 1.5 3 1.5 3.0 6 6.0 7.0 7 7.5 8.0 8 9.5 9.75 10 20.0 20.75 AH-E7 1 0.0 0.5 3 2.0 3.0 GP 61 37 2 2.3 4 3.0 4.0 AH-E8 2 0.5 1.5 3 1.5 2.0 4 3.0 3.75 AH-E9 1 0.0 1.0 2 1.5 2.5 SM 0 71 29 15.7 3 3.0 3.5 5 5.0 5.25 6 6.5 8.0 GM 43 40 17 4.4 *Location shown on Figure 6.43. TABLE 6.11: MATERIAL PROPERTIES - BORROW SITE H a e * Trench Number Sample Number De th (feet) Lab. Classi- fication Mechanicalerberg Anal s"s Li its Specific Gravity Wo rom 10 _TF-Eivell SandFine LL PI AH-HI 1 0.0 1.5 0 75 25 13 2 1.5 3.0 SM 26 49 25 13 3 3.0 4.0 16 4 4.5 6.0 SC 13 66 22 32 17 17 5 6.0 7.5 CL 14 34 52 34 21 16 6 7.5 8.5 CL 18 1 27 55 25 7 12 7 9.0 10.0 12 8 15.0 15.5 GM 66 22 12 21 NP 9 9 20.0 21.5 9 10 25.0 26.5 AH-H2 1 0.0 1.5 2 1.5 3.0 15 62 23 - NP 23 3 3.0 4.0 SM 17 4 4.5 5.5 20 5 6.0 7.0 34 31 35 18 NP 7 6 7.5 8.5 GM 11 7 9.0 10.0 11 8 15.0 16.0 SM 24 23 33 10 9 20.0 20.B3 SM 27 41 32 17 NP 9 10 25.0 25.5 6 11 30.0 30.75 18 42 40 18 5 8 12 35.0 35.7 SM-SC 8 13 40.0 40.75 7 AH-H3 1 0.0 1.5 2 1.5 3.0 3 3.0 4.0 53 4 4.5 5.5 SM-SC 14 44 42 1B 5 19 5 6.0 7.0 14 6 7.5 8.5 7 9.5 10.5 SM 7 52 41 -- NP 12 8 15.0 16.5 SM 17 53 30 14 NP 9 9 20.0 20.25 10 25.0 25.25 AH-H4 1 0.0 1.5 2 1.5 3.0 3 3.0 4.5 GC 45 35 20 23 7 16 4 4.5 5.5 13 5 6.0 7.0 SM-SC 25 35 40 20 4 15 6 7.5 8.5 11 7 15.0 16.0 SM 35 38 27 22 NP 11 8 20.0 21.0 9 25.0 25.5 AH-H5 1 0.0 1.5 2 1.5 3.0 3 3.0 4.0 4 4.5 6.0 SM-SC 22 36 42 23 6 16 5 6.0 7.5 SM-SC 0 55 45 22 6 17 6 7.5 8.5 SM-SC 24 33 33 21 4 9 7 9.0 9.5 24 33 33 21 4 10 8 15.0 15.66 11 30.0 30.25 12 35.0 35.5 AH-H6 1 0.0 1.5 2 1.5 3.0 3 3.0 4.5 4 4.5 6.0 5 6.0 7.0 6 7.5 9.0 SM 22 45 33 - NP 13 7 91.0 10.5 12 8 15.0 15.5 9 20.0 20.25 10 25.0 26.5 SC 10 45 45 23 9 11 11 30.0 31.0 12 35.0 35.5 SM-SC 34 47 19 21 6 8 13 40.0 40.5 8 TABLE 6. 11 (Cont0d) Pole trench Number Sam le NuZer Depth (Feet) a, Classi- fication c 6h cal Ahal a s A orb 6l,� L.. iEa Spbe ifib 6tavik IVY From 1 10 Gravel S!hdFFihb LL Vi AH-H7 1 0.0 1.5 2 1.5 3.0 3 3.0 4.5 4 4.5 5.5 5 6.0 7.5 MC-CL 12 36 52 17 4 14 6 7.5 9.0 17 7 9.0 10.5 CL 7 34 59 29 14 16 8 15.0 16.5 9 20.0 21.5 SC 13 10 25.0 25.66 22 51 27 33 19 13 11 25.66 26.5 12 30.0 30.6 AH.-H8 1 0.0 1.5 2 1.5 3.0 3 5.0 6.5 4 6.5 7.5 - NP 14 5 8.0 9.5 SC 18 40 42 25 11 12 6 9.5 11.0 13 7 15.0 16.5 GC 38 26 36 21 7 7 8 20.0 21.0 GC 40 27 33 21 1 6 9 25.0 26.0 6 10 30.0 30.5 11 35.0 35.25 WOO-256 H GC -SC 29 33 30 21.7 9.2 10.9 WBO-357 H GM-SM 27 37 36 17.1 M 12.3 W61 H 28 34 30 2.12 Wa1 H 43 27 36 23 6 *Locations shown on Figure 6.46 TABLE 6.12: MATERIAL PROPERTIES - BORROW SITES I AND J Hole/* Trench Number Sample Number De th (feet) Lab. Classi- fication Mechanical nal s's Atterberg Li its Specific GravityWA ram To Gravel Sand Fine LL PI TP-R1 1 0.0 1.0 2 1.5 2.0 GW 69 29 2 3 2.0 3.0 4 3.0 3.5 GW 72 26 2 5 3.5 4.5 GW 71 27 2 TP-R2 1 0.0 1.0 GW 77 21 2 2 4.5 5.0 GW 79 19 2 TP-R3 1 1.0 1.5 2 4.5 5.0 GW 71 28 1 TP-R4 1 1.0 1.5 2 4.0 4.5 GW 69 30 1 TP-R5 1 0.5 1.0 GW 64 34 2 2 3.0 3.5 GW 68 31 1 TP-R6 1 1.0 2.0 2 2.0 3.0 ML-SM 1 52 47 TP-R7 1 0.5 1.0 GW 68 31 1 2 3.5 4.0 SW 23 76 1 TP-RB 1 0.5 1.0 GW 72 26 2 TP-R9 1 0.5 1.0 SM 0 75 25 TP-R10 1 1.0 1.5 SM 0 70 30 2 3.5 4.0 SM-SC 36 50 14 TP-R11 1 0.5 1.0 GW 67 31 2 2 3.5 4.0 GW 70 28 2 TP-R12 1 0.5 1.0 GW 67 30 3 2 4.5 5.0 GW 6B 30 2 TP-R13 1 0.5 1.0 2 5.5 6.0 GW 62 36 2 TP-R14 1 0.5 1.0 GW 64 34 2 2 5.5 6.0 GW 64 35 1 TP-R15 1 1.5 2.0 2 5.5 6.0 SM 0 55 45 TP-R16 1 0.5 1.0 SM 0 63 37 2 4.5 5.0 GW-GM 59 35 6 TP-R17 1 1.0 1.5 GW 73 25 2 2 4.0 4.5 GW 59 34 7 TP-R18 1 1.0 1.5 2 4.5 5.0 GW 58 39 3 TP-R19 1 0.5 1.0 2 3.5 4.0 GW 24 73 3 TP-R20 1 0.5 1.0 SM 3 82 15 2 4.5 5.0 GW 62 34 4 TP-R21 1 0.5 1.0 2 4.0 4.5 TP-R22 1 1.0 1.5 GW-GM 65 33 13 2 4.5 5.0 GM B2 17 1 *Locations shown an Figures 6.51 and 6.52. TABLE 6.3: WATANA RQD SUMMARY Borehole DH--1* DH-4 DH-5* DH-6* DH-7* DH-8* DH-9* DH-10 DH-11 DH-12 DH-21 DH-23 DH-24 DH-28 BH-1 BH-2 BH-3 BH-4 BH-6 BH-8 BH-12 Total Rocl Ground Surface El. (Feet) 1459 1462 1462 1716 1716 1910 1913 2033 2034 1951 1480 1952 2061 1971 2050 1835 2150 2185 1605 1976 1966 Drilled - Top Of Rock El. (feet) 1415 1384 1402 1713 1708 1894 1909 2020 2018 1942 1407 1947 2054 1958 2032 1826 2123 2174 1598 1964 1949 Average Borehole Di *-* V V V V 590 V 450 V 450 V 60a 450 V V 700 380 550 590 600 600 400 RQD Vertical Depth (ft) RQD Rock Drilled 0'-50' (ft) 51.4 45.2 47.9 48.9 49.1 54.5 67.0 48.6 70.3 51.6 59.7 70.5 50.9 29.5 52.5 61.2 59.1 56.9 58.5 59.2 81.5 1174. D RQD% 28°0 66% 460 500 48% 59% 59% 2190 71 % 6040 85 u 45.90 700 360 79% 55°o 75,0 o' 44.0 5090 o' 43.0 57% °' 56,0 50' -150' " 27.6 69.2 97.2 64.6 79.3 139.5 100.5 144.1 99.9 110.0 41.7 82.1 62.4 104.8 119.8 124.9 115.7 118.4 116.2 151. 7 1969.6 45% 830 51 o 60 u 67an' 6290 6890 77 0 53 u 85% 49°0 700 1090 76°o 23% 96 0 54 o 6490 7590 72% 65 0 150'-250' " 72.1 34.8 65.0 105.1 121.7 109.6 124.4 120.0 120.8 115.8 114.5 154.0 1257.8 4400 890 85 o 77010 83°0 86 o 54% 991a, 94°0 8690 8240 6890 79 0 250'-350' 33.9 118.3 14.3 85.6 119.9 114.9 115.3 114.6 156.1 872.9 85 0 8290 73°0 75% 8700' 991-0 8100, 7900' 620 800 350'-450' " 109.5 119.5 115.1 114.4 114.3 159.3 732.1 91 0 460 9910 82 840% 79 0 7900' 450'-550' " 120.6 120.0 115.2 117.8 69.3 542.9 96% 790 710 810 830 820 550'-650' 125.0 115.1 94.8 102.0 436.9 96 0 700 79 0 88% 830 650' --750' " 120.0 114. 7 234. 7 96o 74% 860 750'-850 " 15.0 64.0 79.0 10090, 95:a 9b°0 Total Hole Length (feet) 79.0 45.2 117.1 146.1 113.7 133.8 278.6 183.9 279.4 290.5 519.2 112.2 133.0 91.9 281.2 391.0 924.0 937.2 732.4 738.6 771.9 7299.9 Average RQD 3490 66°0 68 0 500 550-1 640 5790 60 0 7890 670 84 0 47% 70% 1 B°0 BO a 49 0 96% 800% 75 o 78% 70% 72% *COE boreholes **V = vertical 0% "�XID CREEK 0 4 _ B M€LES SCALE LOCATION MAP INDEX BLOCK AREA COVERED SCALE* FIGURE NO. REFERENCE I O DAMSITE VICINITY RELICT CHANNEL. 1"-2500' FIGURE 5.1 a TOP OF BEDROCK V=2500' FIGURE 6.35 SEXPLORATION 1"=500' FIGURE 5.1 b ® DAMSITE= TOP OF BEDROCK 1"-500' FIGURE 6.2 GEOLOGIC MAP 1"-500' FIGURE 6.3 OQUARRY SITE A I"=1000' FIGURE 6,37 ® QUARRY SITE B 1"-500' FIGURE 6.36 OBORROW SITES C AND F 1"-5000' FIGURE 6.39 © BORROW SITE D I"=1000' FIGURE 6.40 OBORROW SITE E 1%1000' FIGURE 6.43 OBORROW SITE H I"=2500` FIGURE 6.48 ® BORROW SITE I I"=2500' FIGURE 6,61 04 BORROW SITE J 1%2500' FIGURE 6.52 , QUARRY SITE L 0-500' FIGURE 6,56 + REDUCED REPORT FORMAT 0 f 2 MILES SCALE FIGURE 6.1 ����� LEGEND LITHOLOGY: ? o en 0V ER BUR DEN, AREAS OF TA LU S, OUT WASH, T ILL, TERRACE CEPOSITS, ALLUVIUM, AS SHOWN DIORITE TO QUARTZ DIORITE, INCLUDES MENOR - --- - r✓} I \ GRANODIORITE /2Z00 .�_. _. .. _. -_... �'-�_� - // I TALUS, TIL\ .._.. /` : ._.-�- ,.----'�----' -- -� - _ �� � / '��J ANDESITE PORPHYRY, INCLUpESMINOR DAC#TE ` ---- - AND LATITE 00 / ..<:i:WYt -- -- - :.../ 2� t" DIORITE PORPHYRY 1 LIMIT 0 OUTCROP ...27ta`> .._...... o TILL _ - - - i' ... .... _ _..-._... CONTACTS:. LiTHOLOGIC / UTWASH J --_ - ---- \ - - - - - -' --'- CONTOUR LINES: - _... \ TILL ---- - _... - TELL. i - _ _ - R INTERVAL 100 FEET, / TILL� _-.. SOPCONBOUR5CpASHEDOU - p�, �..,-,� - - - - _ ----- TOP OF BEDROCK, CONTOUR INTERVAL 20 FEET OQO . ?t00 '-�Q �#_ , RACE - I " /-OOSITS DTOPOGRAPHY, CONTOUR INTERVAL 80 FEET �'" ✓' i r� SPRINGS t- S- �..� _- ... TILL. NOTES TILL rf r-`� "� "'- - € `~ - -- _--.}40Q }. SURFIC#AL DEPOSITS M003FIE0 FROM COE,I978. � 2 .--- `----i,.;- W``- TALUS ���' t TALUS. �'� 2. TOP OF BEDROCK CONTOURS ARE INFERRED BASED ON �TILL _ _ �> GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS AND �acp ., � .__ ij TALt1S� -� �i� ' •� �_~\ ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED `�,.�'� '''" ��� INVESTIGATIONS. r .; -� wJ�=',�-/' t....,.,- �..,�" r. /.,/a,a t i .\ _,�, ..00I�- TILL '� -i - ', _�-' ,x_ .__-z :+, `. -�'.--`._'._ - - k.� -L--_" �l7 iI .rs`ti // _ _ t - ' _ —:L '::ALLUVIUM` �'ta:._ - is- ,. TALUS_ - �,../ - — - _- - --'--- r '-rALU$--1400- ,F Iiao N Poo 6I � /' _ — _ J' :� -� TALUS p�D t`�s 1360r _ I ,.� 1A, TALUS % TALUS '�.•.. o, --/�'--;.`'}' 6D ALLUVIUM..\' * _ ALLUVIUM ` -'- -- - - `,� TALUS.. 1 r } 1 / .1rL, Ly f , �r ./ w139 ---.}500- Y , 1�OC_ - r`..j f TALU5 AND `LLUVtAL BOO DERS 1700 ,.. / � �rnws _ � �� � ��� _ ,r'� .� � - �7 „ ,J �.\. tip- - - .L 3 r : - /J I'm ✓-.^:., it f ✓ y \ �Y IBD ._ .... —_—__ __ --� / _ ��.. - - - -•�� � .>_ � 1 :' a'�J / F_,.r;. TALUS r' �_.. 7 \\�, ! /'� ,✓ / / / `,,, DEPOSITS }900- y , TALUS , y TILLE� - Y/ / - TILL OUTWASH l_ _ / T �� 700 ___ �, � ,\ -. .. ._._. TILL----- --- _ � t 11 r } t� - TILL �'/ �/ _ :� �, _ 1 �.i\ \ SCALE 0 200 400 FEET i \ \ J vl� lU+WA HAND I S c4,?;2.�3fA'7 7=7� : i �.... 1� . WATANA /. v- r 1 . ILL A _ No OurwnsH \ I f `? TOP OF FLOCK -:% �/ ; � � � TILL A } '. I �._ f A REFERENCE BASE MAP FROM COE,1978-I°=200' 1 _ ��++ WATANA TOPOGRAPHY, SHEETS 13 AND 13OF26 �' \.``�'/% A D J'URF'-ICIAL GEOLOGIC MAP A n COORDINATES IN FEET, ALASKA STATE PLANE (ZONE 4) \ FIGURE 6.2 NOTES LEGEND I. OUTCROPS SHOWN ON FIGURE 6.2, LITHOLOGY: ru 2. LEGEND FOR EXPLORATION SYMBOLS ON DIORITE TO QUARTZ DIORITE, INCLUDES FIGURE 5.1 MINOR GRANODIORITE 1.2 ... .• . ANDESITE PORPHYR INCLUDES 3. GEOLOGIC SECTIONS ON FIGURES 6.4THRCUGHGB. .... . .. .......... DACITE AND LATITE N r,"N) 4. JOINT PLOTS ON FIGURES 6.12 AND 6,13. A" DIORITE PORPHYRY 5. ADDITIONAL GEOLOGIC DATA FROM COE,1978, GEOLOGIC FIELD BOOKS THRU 2B . CONTACTS: 6. TOPOGRAPHY FROM COE 1978, 1 200', LITHOLOGIC, DASHED WHERE INFERRED, ... .. .. .. DIP WHERE KNOWN 7. EXPLORATION LOGS AND SEISMIC LINE STRUCTURE: SECTIONS IN APPENDICES Fl, D,H, AND 1. S. EXTENT SHER, WIDTH GREATER rHAN 10 FEET� VERTAICAL UNLESS DIP SHOWN OF SHEARS, FRACTURE ZONES AND . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... . . . . . ----- ---- AREA OF MAJOR ALTER.. I N,.' ALTERATION 7DNES ARE INFERRED BASED ON 7 SHEAR, WIDTH LESS THAN 10 FEET, INJBIOR17EISHEAR. AN F GEOLOGIC MAPPING AND SUBSURFACE 515v INCLINED, VERTICAL, EXTENT WHERE ZONES IN. PORPHYRY KNOWN W-5 IATIONS, AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED E FRACTURE ZONE,WIDTH GREATERTHAN 0FEET, VERTICAL UNLESS DIP SHOWN IGATIONS. 70 FRACTURE ZONE, WIDTH LESS THAN 10 FEET, 4NCI-INED, VERTICAL EXTENT WHERE KNOWN '4' "k I, ...... JOINTS; INCLINED, OPEN INCLINED, VERTICAL (SETS I AND I I ONLY, CrFl 71# EXCEPT FOR OPEN JOINTS .0AS OF FRACT ZONES-- E AREAS OF FRACTURE' AND MINOR SHEAR ALTERATION ZONE, WIDTH AS SHOWN ZIONES. MINOR,SR EARS OTHER: ;0 AND ALTE ell !(65 a ZONES E 60 5- E W_ I A A GEOLOGIC SECTION LOCATION T. 70 UGE A WJ-1 JOINT STATION 14 AEAS O� P RWC-T[i l4t_ N E §--00 GEOLOGIC FEATURE DESCRIBED AND5 IN SECTION 6.1 M/INOR SHEARS 6u /74 so r.15 80 'A ell 19/4" - 6 -A � �_82�84 X Be B75 N' 70 Vic a� 6p 65- El 'AZI T' N l%22 -)OQ 75 0 T T R 6 ." FIN GEF66S AREA OF MAJOR Wj- 9,,�, SHEARS x. J�5 wl 84 CG56 Z 7 70' 4 V. B 9 jj v �4RE�Ag OF -SHEARS AND z h bA� `- - JIF7A FIACTURf= 264�.. -AREAS. OF ALTERATION, 5 p T r,�t MINOR SHEARS AND - FRACTURE ZONES ZONES AN SHEARS OF FRACTURE 7A -4 wi- A 9 4 d ...... -MINOR SHEARS AREAS OF FRACTURE-Z E8� IN AND < Bf, `�THE.. FINS' i AREA OF IAJOR ? SHEARS AND �vJ-7 . ...... ALTERATION ZONE 0 200 400 FEET SCALE - ------ ---- ,4474 Wj Qk 84 x 3z z TwV u. n, L .T': T WATANA REFERENCE: BASE MAP FROM COE, 1978 - 1"=700' WATANA TOPOGRAPHY, SHEET 13 a 13 OF 26, COORDINATES IN FEET, ALASKA STATE PLANE (ZONE 4) GEOLOGIC MAP W FIGURE 6.3 uj z 0 4 y w 2500 2000 1500 1000 % RQn fop 50 0 EL. - 2177 ,® AZIMUTH.�i o 343 OF SECTION.I63 LOOKING UPSTREAM 0 % ROD 1010 510 0 FL L I _ 1 - -- 2014 .1. -R00 p g4. %Oo -1602 ROD r s 100 50 0 EL. I I � ID94 DH-10 % ROD lop 50 0 L I EL. - 712 0 DH-8 -i760 N^gyp j0 E4'� DH-9 ✓ •1I PROJECTED 1� 10`W DH-B pI OJECTED PROJECTED 201W DIKE WATANA GEOLOGIC SECTION W-1 SHEET I OF 2 % ROD too 50 0 EL. AM -13T3 —1327 DH-4 DH-21 � BOTTOM BOTTOM 155Q ACTED PROJECTED 330' E (SEE SHT.2) LEGEND LtTHOLOGY: OVERBURDEN, UNDIFFERENTIATED DIORITE TO QUARTZ DIORITE, INCLUDES MINOR GRANOD€ORITE ANDESITE PORPHYRY, INCLUDES MINOR OACITE B LATITE V DIORITE PORPHYRY CONTACTS: --^-- APPROXIMATE TOP OF ROCK --- LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: SHEAR, WIDTH SHOWN WHERE GREATER THAN 10 FEET FRACTURE ZONE,WIDTH SHOWN WHERE GREATER THAN 10 FEET ALTERATION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS: QSW-1 INTERSECTION W$TH SEISMIC REFRACTION L€NE DM-C $975, DAMES S MOORE SW- I 1978. SHANNON B WILSON SL 80-2 1980, WOODWARO-CLYDE CONSULTANTS 2500 SL 81-2.1 1981, WOODW4RD-CLYDE CONSULTANTS ••••••••• SEISMIC VELOCITY CHANGE t2,000 SEISMIC VELOCITY IN FEET PER SECOND FPS 60REHOLES: BH-1 F,FRACTURE ZONE LITHOLOGY S- SHEAR A- ALTERATION ZONE DR-19 COE ROTARY 9 DIAMOND CORE BORINGS DH-I OH-t AAI DIAMOND CORE BORING OTHER; 2000 W-5 1 INTERSECTION WITH GEOLOGIC V' SECTION W-5 GF 2 GEOLOGIC FEATURE DESCRIBED IN SECTION 6.1. NOTES I. SECTION LOCATION SHOWN ON FIGURE 6.3. 2. VERTICAL 9 HORIZONTAL SCALES EQUAL. 3. SURFACE PROFILE FROM I°=200' TOPOGRAPHY, COE, 1978. 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES B,D,H AND 2, 5. EXTENT OF SHEARS,FRAGTURE ZONES,AND ALTERATION ZONES ARE INFERRED BASED ON 1500 GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS, 0 100 200 FEET SCALE 1 1000 FIGURE 6.4 2500 2000 % ROD KXl 50 • 0 I EL. 1394 H i Ld - 1277 z OH-5 0 a W W USITNA DH-21 W' RIVER PROJECTED z 45'W � PROJECTED 1500135'W 1000 ,A BOTTOM PROJECTED 155' W MUTH 343° OF SECTION—�163° LOOKING UPSTREAM as ° 9"p *l p > -" `rpv % ROD 100 50 0 {cis L I EL. 61 -19g0 0 3 or 4 BH - PRR 140i4 DH-23 I SW I W-5I DH-12 -1650 ' DH-12 ; 20,000 FPS S,A W` F BOTTOM PROJECTED 195' W e RQD io So10 EL, ' 1968 % RQD 100 50 0 i.°6 L I EL. - 2055 -1922 DH-24 BH-B 1328 BH-B PROJECTED ITO'E DH•24 SLeA80-21 , I 2,500 FPS 10,000 FPS F --ELSIC DIKE A BOTTO M PROJECTED 68 5' E WATA NA GEOLOGIC SECTION W-1 SHEET 2 OF 2 LEGEND LITHOLOGY: OVERBURDEN, UNDIFFERENTIATED DIORITE TO QUARTZ DIORITE, INCLUDES MINOR GRANOD[ORITE ANDESITE PORPHYRY, INCLUDES MINOR DACITE a LATITE DIORITE PORPHYRY CONTACTS: ----- APPROXIMATE TOP OF ROCK -- LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: SHEAR, WIDTH SHOWN WHERE GREATER FEET FRACTURE ZONE, WIDTH SHOWN WHERE L�.]1111 GREATER THAN 10 FEET ALTERATION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS: �SW-1 INTERSECTION WITH SEISMIC REFRACTION LINE DM-C 1975, DAMES e. MOORE SW-1 1978, SHANNON IN WILSON SL 80-2 1980, WOODWARD-CLYDE CONSULTANTS 2500 SL 81-21 1981, WOODWARD-CLYDE CONSULTANTS ......••• SEISMIC VELOCITY CHANGE 12p00 SEISMIC VELOCITY IN FEET PER SECOND FPS 6OREHOLES: BH-1 F=FRACTURE ZONE LITHOLOGY S=SHEAR A -ALTERATION ZONE DH COE ROTARY B DIAMOND CORE BORINGS DH-I -1 BH-1 AAI DIAMOND CORE BORING OTHER 2000 W-5 1 INTERSECTION WITH GEOLOGIC �V SECTION W-5 GF 2 GEOLOGIC FEATURE DESCRIBED IN SECTION 6,1. NOTES 1. SECTION LOCATION SHOWN ON FIGURE 6.3. 2. VERTICAL B, HORIZONTAL SCALES EQUAL, 3, SURFACE PROFILE FROM 0=200' TOPOGRAPHY, COE,197R, 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES B,D,H AND I. 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON 1500 GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. 1000 0 100 200 FEET SCALE FIGURE 6.4 ACRES 023* AZIMUTH 0 203. OF SECTION LOOKING UPSTREAM 2500 THE FINS" AREA OF MAJOR SHEARS a ALTERATION ZONES SW-36 SW-3 PROJECTED PROJECTED 15, 10 E E PROJECTED 80-38 qq SL 81-15X 47E PROJECTED SL T ECTED e DR-l9 PROJECTED 4 404 WE U - � IB 000 FPS � 12,200 FPS - _.,-..,...,.,.,.. ;f.10�500. 2000 J PROJECTED FOPS INTAKE APPROACH 9'E 10,500 FPS CHANNEL ~" ti r -I tisy;,;v C C f ) n W GF2 nV SEISMIC VELOCITY CHANGE AREAS OF o AS PROJECTED FROM SW3,4I5'E FRACTURE ZONES TREND 9 MINOR SHEARS I 1 C I500 � ? TREND 315° I' TREND 310° -�� TREND 31C° yy L TREND 310 1 , Gi TUNNELS N Y 1000 WATANA GEOLOGIC SECTION W-2 SHEET I OF 2 ml. 2500 H 2O00 i 1500 LEGEND LITHOLOGY: OVERBURDEN, UNDIFFERENTIATED DIORITE TO QUARTZ DIORITE, INCLUDES MINOR GRANODIORITE ANDESITE PORPHYRY, INCLUDES MINOR OACITE B LATITE DIORITE PORPHYRY CONTACTS: ---- APPROXIMATE TOP OF ROCK -- LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: SHEAR WIDTH SHOWN WHERE GREATER _.h. �t THAN l0 FEET FRACTURE ZONE, WIDTH SHOWN WHERE GREATER THAN 10 FEET ALTERATION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS: QSW-I INTERSECTION WITH SEISMIC REFRACTION LINE DM-C 1975, DAMES 6. MOORE SW-1 1978, SHANNON 8 WILSON SL 60-2 1980, WOODWARD-CLYDE CONSULTANTS SL 8 -21 1981 WOOD AR - TA I W D CLYOE CONSULTANTS SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND FPS BOREHOLES: BH-t F=FRACTURE ZONE LITHOLOGY S= SHEAR A=ALTERATION ZONE DR_ 19 DHCOE ROTARY H DIAMOND CORE BORINGS -I BH-I AAI DIAMOND CORE BORING OTHERt W-5 4INTERSECTION WITH GEOLOGIC SECTION W-5 GF 2 GEOLOGIC FEATURE DESCRIBED IN SECTION 6.L NOTES 1. SECTION LOCATION SHOWN ON FIGURE 6,3. 2. VERTICAL 8 HORIZONTAL SCALES EQUAL. 3. SURFACE PROFILE FROM 0=200' TOPOGRAPHY, COE,1978. 4, EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES B,D,H AND 2. 5, EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS, 0 IDO 200 FEET SCALE 1000 FIGURE 6.5 jG 2500 (E DAM CREST EL.2210 i j Y ROD % ROD Mo 50 0 2000 IQ0 50 O I 1 i - I I EL. - 1394 - 1376 imms -1327 4,77 1 DH-4 DH-5 1500 1000 PROJECTED PROJECTED 520'E 430E TREND GF 5 AREA OF FRACTURE ZONES AND MINOR AZIMUTH 023" ld—OF SECTION --b- 203 ° LOOKING UPSTREAM % ROD 100 50 0 i EL, - 1940 pp p 1 b, Oary - 1650 DH-12 DH PR 7n e BN,B SW-1 Q BHP DH-24 DH-24 PROJECTED PROJECTED .23 10' W 181 W )JECTED f BH-B F1 FPS SL 81- 21 r%g A F' PROJECTED 295' W p S,F BOTTOM PROJ. 60' W 16,060-20,000 FPS S,A F BOTTOM PROJECTED 225' W 0 EL. - 2055 - 1922 DH-24 SL BI-21 PROJECTED IGO' E SL 81-21 I6,000; , `R^ FPS LEGEND LITHOLOGY: OVERBURDEN, UNDIFFERENTIATED DIORITE TO QUARTZ DIORITE, INCLUDES MINOR GRANODIORITE ANDESITE PORPHYRY, INCLUDES MINOR DACITE a LATITE DIORITE PORPHYRY CONTACTS: ----- APPROXIMATE TOP OF ROCK -- LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: WOSHEAR, WIDTH SHOWN WHERE GREATER THAN 10 FEET 2500 FRACTURE ZONE, WIDTH SHOWN WHERE \1�1' GREATER THAN 10 FEET - ALTERATION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS: QSW-1 INTERSECTION WITH SE€SMIC REFRACTION LINE DM-C 1975, DAMES B. MOORE SW-1 1978, SHANNON A WILSON SL 80-2 1980. WOODWARD-CLYDE CONSULTANTS SL 81-21 1981, WOODWARD- CLYDE CONSULTANTS ......••• SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND FPS BOREHOLES: Bk-1 2000 Fa FRACTURE ZONE LITHOLOGY S=SHEAR A= ALTERATION ZONE DR-I9 DDIRT COE ROTARY & DIAMOND CORE BORINGS BH-1 AAI DIAMOND CORE BORING OTHER- W-5 I INTERSECTION WITH GEOLOGIC V' SECTION W-5 GF 2 GEOLOGIC FEATURE DESCRIBED IN SECTION 6,1. 1 1500 NOTES I. SECTION LOCATION SHOWN ON FIGURE 6.3. Z. VERTICAL B HORIZONTAL SCALES EQUAL, 3. SURFACE PROFILE FROM 0-200' TOPOGRAPHY, COE,1976. 4- EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES B,D,H AND I. 5. EXTENT OF SHEARS,FRACTURE ZONES,AND ALTERATION ZONES ARE €NFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. 0 100 200 FEET SCALE WATANA GEOLOGIC SECTION W-2 SHEET 2 OF 2 RR FIGURE 6,5 W LL 2500 € 2000 F 1500 1000 L a-""O PROJECTED 25' W SW-2 DH-II W-1 9 W-4 MAIN SPILLWAY /�y I H-10 APPROACH CHANNEL a •'VV -6,020 FPS WW CONTROL STRUCTURE S,A SERVICE (yy S,A SPILLWAY.: -A F $6,000 A FPS �. a.. S,A S,A sF S,F -S,A S,A AREAS OF FRACTURE ZONES �- ACCESS A TREND 310HEAR5 � ,�• GROUT TUNNEL ACCESS GALLERY S A TUNNELS 8,F POWERHOUSE, TRANSFORMER GALLERY, a SURGE CHAMBER PROJECTED 325'S TREND 3059 B OM DIVERSION PROJECTEDS,A �. TUNNELS PENSTOCKS 445'E/ r�1 315" WATANA GEOLOGIC SECTION W-3 SHEET I OF 2 SUSITNA RIVER - DM-C PROJECTED I ID' E I 6,100 �PS LEGEND LITHOLOGY: OVERBURDEN, UNOIFFERENTIATED DIORITE TO QUARTZ OIOR€TE, INCLUDES MINOR GRANODIORITE ANDESITE PORPHYRY, INCLUDES MINOR DACITE 8 LATITE DIORITE PORPHYRY CONTACTS: ----- APPROXIMATE TOP OF ROCK --- LITHOLOGIC, DASHED WHERE €NFERRED STRUCTURE: SHEAR, WIDTH SHOWN WHERE GREATER THAN 10 PEET FRACTURE ZONE,WIDTH SHOWN WHERE GREATER THAN 10 FEET _ ALTERATION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS: QSW�I INTERSECTION WITH SEISMIC REFRACTION LINE DM-C 1975, DAMES d MOORE 2500 SW-1 1978,SHANNON B WILSON SL 80-2 €980, WOODWARD-CLYDE CONSULTANTS SL 8I-21 1981, WOODWARD-CLYDE CONSULTANTS .......•• SEISMIC VELOCITY CHANGE 12POO SEISMIC VELOCITY IN FEET PER SECOND FPS BOREHOLES: BH- I FRACTURE ZONE ZONE LITHOLOGY S=SHEAR A=ALTERATION ZONE DR-19 COE ROTARY s DIAMOND CORE BORINGS DH-1 2000 SH-1 AA1 DIAMOND CORE BORING OTHERt W-5 I INTERSECTION WITH GEOLOGIC W SECTION W-5 GF 2 GEOLOGIC FEATURE DESCRIBED IN SECTION 6.1. NOTES I. SECTION LOCATION SHOWN ON FIGURE 6.3. 2. VERTICAL a HORIZONTAL SCALES EQUAL. 3. SURFACE PROFILE FROM I"=200' TOPOGRAPHY, COE, 1978. 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS I500 SHOWN IN APPEND€CIES B,D,H AND I. 5, EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS, AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. I 1000 0 100 200 FEET SCALE FIGURE 6.6 IN-- 2500 2000 ROD 100 50 0 % ROD 1 FL, 100 50 0 - 1381 1 1 I EL. -1204 - 1408 -1329 CH-3 DH-I DM-C 1500 AZIMUTH 026"� OF SECTION---l-208- LOOKING UPSTREAM -SHEAR, 0.2' GOUGE 1„ TREND 297° r GF 6B _SHEAR, 3GOUGE TREND 32525° GORE LOSSI S,F i 6, 7' IB,DOO E SUSITNA RIVER DH-I FPS / VARE.""!F - il FRACTURE ZONES 9 SHEARS POSSIBLE SHEAR TREND 310° OR FRACTURE ZONE (DIP INFERRED) 1000 SW-1 W-5 T I,250 FPS .I. � ..... _...__ 2000 TREND WATA N A GEOLOGIC SECTION W-3 SHEET 2 OF 2 1500 1000 LEGEND LITHOLOGY: OVERBURDEN, UNDIFFERENTIATED DIORITE TO QUARTZ DIORITE, INCLUDES MINOR GRANODIORITE ANDESfTE PORPHYRY, INCLUCES MINOR DACITE B LATITE DIORITE PORPHYRY CONTACTS= --- APPROXIMATE TOP OF ROCK ---- LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: SHEAR,WIDTH SHOWN WHERE GREATER THAN IO FEET 7 FRACTURE ZONE, WIDTH SHOWN WHERE LL - GREATER THAN 10 FEET ALTERATION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS: QSW-I INTERSECTION WITH SEISMIC REFRACTION LINE DM-C 1975,DAMES & MOORE SW-1 19713, SHANNON B WILSON SL 80-2 1980. WOODWARD-CLYDE CONSULTANTS SL 8t-21 19B1, WOODWARD-CLYDE CONSULTANTS ......••• SEISMIC VELOCITY CHANGE 12.000 SEISMIC VELOCITY IN FEET PER SECOND FPS BOREHOLES: BH-I FRACTURE ZONE ZONE LITHOLOGY 5=SHEAR A= ALTERATION ZONE DR-19 OH-1 COE ROTARY B DIAMOND CORE BORINGS BH-I AAI DIAMOND CORE BORING OTHER: W-5 I INTERSECTION WITH GEOLOGIC `Y SECTION W-5 GF 2 GEOLOGIC FEATURE DESCRIBED IN SECTION 6,1. NOTES I. SECTION LOCATION SHOWN ON FIGURE 6.3. 2, VERTICAL 9 HORIZONTAL SCALES EQUAL. 3, SURFACE PROFILE FROM I°=200' TOPOGRAPHY, COE,1978. 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES B,D,H AND X. 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. 0 100 200 FEET SCALE FIGURE 6.6 A CRES LEGEND LITHOLOGY: OVERBURDEN, UNDIFFERENTIATED OIORITE TO QUARTZ DIORITE, INCLUDES MINOR GRANDDIORITE ANDESITE PORPHYRY, INCLUDES MINOR OACITE a LATITE 086° OF SECTITH ON 0- 266° DIORITE PORPHYRY LOOKING SOUTH CONTACTS: - -- APPROXIMATE TOP OP ROCK -- LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: r* J, SHEAR, WIDTH SHOWN WHERE GREATER THAN €0 FEET FRACTURE ZCNE, WIDTH SHOWN WHERE LU\�1 GREATER THAN €O FEET ALTERATION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS: QSW-1 INTERSECTION WITH SEISMIC REFRACTION LINE DM-C 1975, DAMES B MOORE SW-1 i978, SHANNON a WILSON SL BO 2 €9BO, WOODWARD-CLYDE CONSULTANTS SL 81-21 1991, WOODWARD-CLYDE CONSULTANTS •.......• SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND FPS BOREHOLES: BH-I SL 80-3 F= FRACTURE ZONE 2000 1,650 LITHOLOGY FPS 2000 S=SHEAR A, ALTERATION ~22,200 FPS Z ZONE R-1 DCOE ROTARY a DIAMOND CORE BORINGS ¢ BH-I AAI DIAMOND CORE BORING OTHER- GF2 W-5 I INTERSECTION WITH GEOLOGIC W SECTION W-5 AREAS OF FRACTURE ZONES T J�9 8; MINOR SHEARS 1 GF 2 GEOLOGIC FEATURE DESCRIBED IN TREND 310° SECTION 6.1. PROJECTED .'•t tao'B SUSITNA RIVER w (LOOKING DOWNSTREAM) INTERSECTION WITH DIVERSION TUNNELS SOUTH DIVERSION TUNNEL NOTES LL z 1600 I. SECTION LOCATION SHOWN ON FIGURE 6.3. ti:r:c':_;,_,- - 1500 p- VERTICAL 8 HORIZONTAL SCALES EQUAL. 3 SURFACE PROFIL E LE FROM I =200' TOPOGRAPHY, C0E,1978. "'=w pROJ. GF IA 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS TREND 3251 SHOWN IN APPENDICIES 9,0,H AND I. 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON TREND 320° i� GEOLOGIC MAPPING AND SUBSURFACE SHEAR, EXPLORATIONS, AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED I- s' GOuGE INVESTIGATIONS, 1000 WATANA GEOLOGIC SECTION W-4 SHEET I OF 3 1000 0 100 200 FEET SCALE FIGURE 6.7 ACRa LEGEND W-2 2000 - I w[ z W d f w w LL = 1500 O h W I J W I NTERSI NORTH 1000 SW-2C PROJECTED 35' S4 ,I I UOO FPS 086"f— AZIMUTH �"-266° OF SECTION LOOKING SOUTH RIVER FLOW—® PL DAM CREST EL.2210 FPS j DIVERSION TUNNELS TREND 320° 0 % ROD 100 50 D 2p�R EL 2014 IB30 DH-10 PROJECTED 65'S SW-2 IQ PROJECTED W-1 l0o's a DH-10 OH-11 W-3 \ 11 / '1250 FPS , t3 I3000 FPS GF 5 F... A... AREAS OF ,6t FRACTURE ZONES yY 9 MINOR SHEARS TREND 3€0° BOTTOM PROJECTED w I80'S 12,500 FPS x J 16,200-18,000 FPS \ �7e —TREND V ACCESS 305° � TUNNEL POWERHOUSE,TRANSFORMER GALLERY, B \\\ SURGE CHAMBER PROJECTED 6308 A WATANA GEOLOGIC SECTION W-4 SHEET 2 OF 3 LITHOLOGY: OVERBURDEN, UNDIFFERENTIATED DIORITE TO QUARTZ DIORITE, INCLUDES MINOR GRANODiORITE ANDESITE PORPHYRY, INCLUDES MINOR OACITE 9 LATITE DIORITE PORPHYRY CONTACTS: APPROXIMATE TOP OF ROCK ^-- LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: .1771i;SHEAR, WIDTH SHOWN WHERE GREATER THAN IO FEET FRACTURE ZONE, WIDTH SHOWN WHERE GREATER THAN IO FEET ALTERATION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS: QSW-I INTERSECTION WITH SEISMIC REFRACTION LINE DM-C 1975, DAMES 9 MOORE SW-1 I978,SHANNON d WILSON SL 80-2 1980, WOODWARD-CLYDE CONSULTANTS SL 8I-21 1981, WOODWARD- CLYDE CONSULTANTS SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND .. FPS BOREHOLES: BH-I FRACTURE ZONE 2000 LITHOLOGY 5^SHEAR A, ALTERATION ZONE DR•19 DH•I COE ROTARY B DIAMOND CORE BORINGS OH-1 AAI DIAMOND CORE BORING OTHER- W-5 �INTERSECTION WITH GEOLOGIC SECTION W-5 GF 2 GEOLOGIC FEATURE DESCRIBED IN SECTION 6.1. NOTES 1600 I. SECTION LOCATION SHOWN ON FIGURE 6.3. 2. VERTICAL & HORIZONTAL SCALES EQUAL. 3. SURFACE PROFILE FROM 1"° 200' TOPOGRAPHY, COE,1978. 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICES B,D,H AND I. 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. 1000 0 100 200 FEET SCALE FIGURE 6.7 ACRES 2000 1000 F— AZIMUTH �� On* OF SECTION 266o LOOKING SOUTH RIVER FLOW RRD IOp� 0 6L 2032 BH-I `f768 SW-2 SL 00-2 PROJECTED loo's rp PROJECTED 145' S 11250 FPS 13,000 FPS S,A —"— ' ••• GF7A (' •� 16,200 FPS AREAS OF ALTERATION, W J1 PROJECTED F MINOR SHEARS B FRACTURE ZONES x 230' S TREND 310' U a SERVICE SPILLWAY_ y\^\'\1/ I.: TREND 0" j--DIVERSION �J PROJECTED 495' N TREND 3$0- ii TREND I. 015, /00 0 0 FL I �/g3j BH2 ' SW-2A \/5/0 PROJECTED "FINGERBUSTER" 220'S AREA OF MAJOR SHEARS FPS BH- 2 rr. PROJECTED ~ � 'GF7B '.!' ! 16,200 FPS ; AREAS OF"•-;" FRACTURE -`, ZONES 8& `:•:- � SHEARS TREND 300°4, ' AREA OF SHEARS & FRACTURE ZONES,'— F. TREND 345 WATANA GEOLOGIC SECTION W- 4 SHEET 3 OF 3 LEGEND LITHOLOGY: 179 OVERBURDEN, UNDIFFERENTIATED DIORITE TO QUARTZ DIORITE, INCLUDES MINOR GRANODIORITE ANDESITE PORPHYRY, INCLUDES MINOR DACITE a LATITE DIORITE PORPHYRY CONTACTS: _---- APPROXIMATE TOP OF ROCK -- LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: SHEAR, WIDTH SHOWN WHERE GREATER THAN 10 FEET FRACTURE ZONE, WIDTH SHOWN WHERE GREATER THAN 10 FEET ALTERATION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS: QSW-I INTERSECTION WITH SEISMIC REFRACTION LINE DM-C 1975, DAMES B MOORE SW-1 1978,SHANNON 9 WILSON SL 80-2 1990, WOODWARD-CLYDE CONSULTANTS SL SI 21 1961 , WOODWARD-CLYDE CONSULTANTS SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND FPS BOREHOLES: BH-I F= FRACTURE ZONE 2000 LITHOLOGY 111 S= SHEAR A- ALTERATION ZONE DR-19 DH-I COE ROTARY a DIAMOND CORE BORINGS BH-I AAI DIAMOND CORE BORING OTHER1 W-5 I INTERSECTION WITH GEOLOGIC W SECTION W-5 GF 2 GEOLOGIC FEATURE DESCRIBEDIN SECTION 6.1, NOTES 1500 I. SECTION LCCATION SHOWN ON FIGURE 6.3. Z. VERTICAL & HORIZONTAL SCALES EQUAL. 3. SURFACE PROFILE FROM I"= 200' TOPOGRAPHY, COE, 1978. 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES B,D,H AND I. 5. EXTENT OF SHEARS,FRACTURE ZONES,AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS, AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. 1000 0 100 2Q0 FEET SCALE FIGURE 6.7 �Cll� LEGEND LITHOLOGY: OVERBURDEN, UNDIFFERENTIATED DIORITE TO QUARTZ DIORITE, INCLUDES MINOR GRANODIORITE ANDESITE PORPHYRY, INCLUDES MINOR = DACITE a LATITE F17 DIORITE PORPHYRY CONTACTS: -^^-- APPROXIMATE TOP OF ROCK -- LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE : SHEAR, WIDTH SHOWN WHERE GREATER THAN 10 FEET FRACTURE ZONE, WIDTH SHOWN WHERE ` GREATER THAN 10 FEET ALTERATION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS: tsw-1 INTERSECTION WITH SEISMIC REFRACTION LINE DM-C 1975,DAMES B MOORE SW-1 1978, SHANNON 9 WILSON SL 80-2 1980, WOODWARO-CLYDE CONSULTANTS SL 81-21 19W, WOODWARD-CLYDE CONSULTANTS •.•.••••• SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND FPS 2500 2000 310' 1600 BOREHOLES: BH-1 ..FRACTURE ZONE LITHOLOGYJ�5 AZIMUTH 0920 S=SHEAR OF SECTION-- 272° A= ALTERATION Li ZONE LOOKING SOUTH DR-I9 DH-I COE ROTARY 9 DIAMOND CORE BORINGS RIVER FLOW BH-1 AAI DIAMOND CORE BORING OTHER: W-5 I INTERSECTION WITH GEOLOGIC �k' SECTION W-5 GF 2 GEOLOGIC FEATURE DESCRIBED IN SECTION 6.1. NOTES I. SECTION LOCATION SHOWN ON FIGURE 6.3. 2. VERTICAL a HORIZONTAL SCALES EQUAL. 3, SURFACE PROFILE FROM I"=200' TOPOGRAPHY, COE,1978. 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES B,D,H AND 2. 5- EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS, AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. SL 81-20 PROJECTED 130 S -25T BOTTOM PROJECTED 40' S GF 5 4REAS OF FRACTURE ZONES I MINOR SHEARS 16,000 - 20,000 FPS 4 aY'jlll� no 0 9ge % ROD N 100 50 0 EL. n40 o cp �t 011A Or.2 �I - 1650 OH-12 � DH-23 SL 81-21 SL 60-20 a PROJECTED PgW-IA 35' S 401S PROJECTED BH-12 90`S PROJECTED 70' N DH-12 W-2 1 BH-8 PROJECTED II.i1 PROJECI _40'S— W 110'N m:llwArs BOTTOM PROJECTED 85 S WATANA GEOLOGIC SECTION W- 5 % ROD 100 50 0 EL l 1 `�32a -1956 SW -I PROJECTED 20' N DH-28 -1846 „� 1250 FPS I FPS.' DIKE BOTTOM PROJECTED 595' N 0 100 200 FEET SCALE SW -I IDH-28 FIGURE 6.8 2000 1� j R MCTURE EATION ANDESITE PORPHYRY OUTCROP RIVER LEVEL -NORTH BANK RAVER AREA WATANA ANDESITE PORPHYRY FLOW STRUCTURE a INCLUSIONS FIGURE 6.9 ANDESITE PORPHYRY ABOVE DIORITE OUTCROP APPROX. EL. 1800 FEET -SOUTH BANK WATANA FRACTURE ZONE IN ANDESITE PORPHYRY FIGURE 6.10 lull HEALED DIC IN ANDESITE/ utum i t MATR IX FELSIC DIKE DIORITE RIVER LEVEL -NORTH BANK `1THE FINS° AREA HEALED SHEAR FIGURE 6.11 JOINT STATION N JOINT STATION WJ-5 N=100 N JOINT STATION WJ-6 N=100 SUS JOINT STATION WJ- 3 N=80 S S n-9� E SET SET S Ii wJ -I wJ-2� - JOINT STATION WJ-4 N=100 WATANA JOINT STATION PLOTS JOINT STATION WJ-9 N=100 0 200 100 FEET SCALE WJ^ NOTES I. CONTOURS ARE PERCENT OF JOINTS PER 1 % OF AREA. CONTOURS SHOWN-1,3,5,7,10,a 15q. P. N EQUALS NUMBER OF DATA POINTS. FIGURE 6.12 Acl In n s 3 II2 T SET 3`5D E �[ SET SET III I\ COMPOSITE JOINT PLOT SOUTHEAST QUADRANT N=72I NORTHEAST QUADRANT N=525 SET 3 ` I SET COMPOSITE JOINT PLOT SOUTHWEST QUADRANT N=329 R r y g R WJ-4 WATANA COMPOSITE JOINT PLOTS COMPOSITE JOINT PLOT NORTHWEST QUADRANT N=600 0 200 400 FEET _F NOTES I. CONTOURS ARE PERCENT OF JOINTS PER IY OF AREA, CONTOURS SHOWN - 1 ,3, 9 5 %. P. N EQUALS NUMBER OF DATA POINTS. 3. COMPOSITE PLOTS INCORPORATE ALL JOINT DATA FROM THEIR RESPECTIVE QUADRANTS. 4. JOINT PLOTS FOR JOINT STATIONS {WJ-1,2,3,4,5,6,7,8d91 ON FIGURE 6.12 5. FOR JOINT PLOTTING METHOD SEE FIGURE 6.12 FIGURE 6,13 SHEAR VIEW LOOKING NORTH ALONG STRIKE OF SHEAR; DIP 570 WEST RIVER LEVEL -NORTH BANK ,,THE FINS" AREA WATANA TYPICAL SHEAR FIGURE 6.14 �UIIS CARBONATE EAST SIDE OF 55 FT. WIDE SHEAR/ALTERATION ZONE RIVER LEVEL -NORTH BANK "THE FINS! AREA WATANA SHEAR/ALTERATION ZONE FIGURE 6.15 ll� DIORITE GF Al DIORITE/ANDESITE PORPHYRY sSUUSII�TNA RIVER �w AERLAL VIEW OF "THE FINS" LOOKING NORTHWEST ALONG STRIKE NOTE: GEOLOGIC FEATURES GFAIAND"THE FINS" DISCUSSED IN SECTION 6.1. WATANA "THE FINS" FIGURE 6.16 ��II� VIEW LOOKING NORTHEAST NORTH BANK NOTE., GEOLOGIC FEATURES GF4 AND GF5 DESCRIBED IN SECTION 6.1. WATA N A GEOLOGIC FEATURES GF 4 AND GF 5 FIGURE 6.17 GF 7B BH-2 �FINGERBUSTER" x 0. O a. W I— F- U) W O ® p z Q GF 7B NOTES; I. GEOLOGIC FEATURES "FINGERBUSTER ; GF 7B, AND GF 7C DESCRIBED IN SECTION 6.1. 2. ANDESITE PORPHYRY & DIORITE CONTACT ALONG FINGERBUSTER" SHEAR. WATANA "FINGERBUSTER"AREA NORTH BANK FIGURE 6.19 �il�� GF 713 VIEW LOOKING NORTHWEST ANDESITE PORPHYRY OUTCROP RIVER LEVEL -NORTH BANK NOTE - GEOLOGIC FEATURES "FINGER BUSTER" AND GF 7B DESCRIBED IN SECTION 6.1. WATA N A GEOLOGIC FEATURE GF iB FIGURE 6.20 C�� TYPICAL COMPRESSION TYPICAL TENSILE TEST FAILURE TEST FAILURE ALTERED DIORITE- ALTERED DIORITE - COMPRESSION TEST TENSILE TEST WATANA ROCK TESTS FIGURE 6.21 C�S 21 12 9 ROCK TYPE: ANDESSTE 6 FAILURE STRESS: 20,333 psi ET50`9.9xIO61`5i, v=0.24 ES=10AX106ps€, v =0.25 3 BOREHOLE BH-2 , SAMPLE No.: 2-BO OF PTH = 27.05 FEET' L/D=2.55 r=166,9 pof O.D9 0.06 0.03 0 0.03 0.06 0.09 0.12 0.15 0.18 (+) STRAIN M.) (-) 21 12 9 ROCK TYPE; DIORITE 6 FA€LURE STRESS; 20,833 psi ET50 = IO.S x 106 psi, v =0.27 ES=10.1 x106psi, v=0.26 3 BOREHOLE: HH-3, SAMPLE No.: W-3-320.7 DEPTH = 320.7 FEET L/D =2.60 r _ 169.2 pci 0.06 0,03 0 0.03 0.06 0.09 D.l2 0.15 0.18 0,21 (+) STRAIN (%)-) 18 9 ROCK TYPE: ANDES€TE 6 FAILURE STRESS: 17,283 psi ET50=10.5XI06psi, v=0.27 ES=10.5 x 106 psi, v=0.27 3 BOREHOLE- BH-2, SAMPLE No.:3-80 DEPTH = 45.3 FEET L/D=2.56 r=166.6pCf 0,06 0.03 0 0.03 0.06 0.09 O.I2 0.15 0.18 (+) STRAIN (% H 0.06 0.03 (+) ROCK TYPE DIORITE FAILURE STRESS: 14,414 psi ET50 = 9.9 x 106 psi, v =0.24 ES = 9.9 x 106 psi, v =0.24 BOREHOLE: SH-4 , SAMPLE No.: W-4-690.8 DEPTH = 690.6 FEET LID -2.42 r=16&.5pcf 0 0.03 0.06 0.09 0.12 STRAIN NO {-) WATANA STATIC ELASTIC PROPORTIES FOR ANDESITE AND DIORITE LEGEND O AXIAL STRAIN VOLUMETRIC STRAIN 0 DIAMETRIC STRAIN ES SECANT MODULUS ET50 TANGENT MODULUS AT 50% FAILURE STRESS v POISSONS RATIO r UNIT WEIGHT L/D LENGTH/DIAMETER RATIO NOTE SAMPLE DIAMETER = I.77° FIGURE 6.22 i�ll 3V[ 28( 26C 24C 22C 200 180 0 g 160 z 140 w 120 100 80 60 40 20 0 a, 01 - 30 SHEAR DISPLACEMENT fN INCHES 100 =31�, C=24PSI BO N 60 n _ in Op=44 �R =31° w y a 40 / W N / ROCK TYPE: DIORITE BOREHOLE: SH-4 20 / SAMPLE: W-4-535.8 / SAMPLE AREA: 2,775 $O. IN. 0 0 20 40 60 so 100 120 140 (60 NORMAL STRESS (PSI) POLISHED DIORITE ON MORTAR, DRY 100 ROCK TYPE: DIORITE BOREHOLE: 8H- 4 SAMPLE: W-4-535.8 DEPTH" 535,8 BO SAMPLE AREA: 2.775 SQ, IN. Ln a m 60 �p = 2f.5` - W A rc N 40 W 20 0 0 20 40 60 80 100 120 140 160 NORMAL STRESS(PSI) POLISHED DIORITE ON DIORITE, DRY WATANA DIRECT SHEAR TESTS LEGEND 240 op PEAK FRICTION ANGLE [] OR RESIDUAL FRICTION ANGLE 220 0 PEAK VALUES ® RESIDUAL VALUES 200 0 VERTICAL DISPLACEMENT 0 NORMAL LOAD= 25 P 3 1 [ IT] a NORMAL LOAD 75 PSI 200 Il El NORMAL LOAD =150 PSI Fl O Fl C APPARENT COHESION ❑ FRICTION ANGLE ENVELOPE 160 ❑ Fl 140 12011 NOTES 0 a t. MAXIMUM SHEAR BOX DISPLACEMENT=0.3 INCHES z_ a 2, STRAIN RATE = 0.039 IN. / MIN. 0 100 A �A a w so 0 p O As 60 F z w 0 w 40 Q O " O aw Oo o 20 ep00000 0.05 U O01�000000 i O 0.05 0.10 0.15 0.20 0.25 0.30 0.35 SHEAR DISPLACEMENT [N INCHES 120 / 100 A =29 PSI --.---7--.. 80 a .../ �R ' 28° 60 W w 40 / ROCK TYPE: GRANODIORiTE BOREHOLE : BH-8 SAMPLE: 80-36 20 DEPTH: 474.3 SAMPLE AREA: 1.93 SO. IN. 0 0 20 40 60 80 100 120 140 160 NORMAL STRESS (PSI) NATURAL JOINT; ROUGH, PLANAR W/CARBONATE, DRY FIGURE 6.23 9 CIN K, COEFFICIENT OF PERMEABILITY (CM/SEC) 10 2 IO-3 IO 4 t0-5 10 6 10-7 0 100 200 W W u- 300 x a W 0 W J O 400 W w O to J a U 500 uw 600 700 BOO WATANA ROCK PERMEABILITY FIGURE 6.26 O O O PERMEABILITY � O � VERAGE 1 � I pAAXIMURA�� MfNIPelUM ja \ 1 � J f � t � i j ° l o � � BASED ON : f3H-I, BH-4, BH-6,BH-8, 1 Q BH-12,DH-I,DH-3,DH-6, DH-B,DH-II I l 1 O TEMPERATURE ('C) -5 -4 '3 -2 -I 0 I 2 3 4 5 2€50.7 0 2140 STICK UP - 4A FEET (1981 ) DIP - 55' (I f -I 1-81) NOTE : SCALE ADJUSTED ACCORDING 2124.7 TO FIELD BOOK CHANGES. 2120 40 2100 BO 21B0 2060 r w v 120 w IL J a 2040 = o ; s 0 W � J W 2020 H 160 w 0 2000 200 1900 1960 240 1940 2B0 BH-3 TEMPERATURE ('C) 1608.E 0 5 -4 -3 -2 -1 0 1 2 3 4 5 1601.9 I580 40 1560 1540 BO €520 t- w w 120 w 1500 w w J z = o z y 1480 o w p w H 160 w 0 1460 1440 200 1420 1400 240 1380 280 STICK UP- O.0 FEET (1981) DIP-60' SUSPECTED - READING ERROR-\ BH-6 NOTE; DUE TO PROBLEMS ENCOUNTERED IN FIELD MEASUREMENTS, THE FOLLOWING ADJUSTMENTS WERE PERFCRMED TO CONFORM TO EXISTING RELIABLE DATA. THESE FIXED LATERAL SHIFTS MAY NOT CORRECT THE FULL MAGNITUDE OF THE DISCREPANCIES. ADJUSTMENT SUBTRACTED DATE OF READING FROM CALCULATED READING ('CI II-21-80 14.92 4-26-81 13.95 5-24-BI 14.63 6-25-81 14.54 B- 3-BI 14.82 WATA N A THERMISTOR DATA-DAMSITE SHEET ! OF 2 LEGEND LITHOLOGY: GROUND SURFACE r)M) TOP OF ROCK WREHOLES� AP AUGER BORING DH DIAMOND CORE BORING CORPS OF ENGINEERS DR ROTARY DRILL HOLE 11978 ) AH AUGER HOLE ACRES AMERICAN INCORPORATED SH BORE HOLE (1980 a 1901 ) DATA SOURCES INDEX OF THERMISTOR READING DATES a JULY 30,1960 4 NOVEMBER 21, 19B0 O APRIL 19, 1961 X MAY 24, 1981 ❑ JUNE 24, 1981 o AUGUST 3,19811 ® NOVEMBER If, 1981 NOVEMBER 13, 1981 0 DECEMBER 9,1981 ® DECEMBER 15 8 16, 1981 I> JANUARY 4-7, 1982 CORPS OF ENGINEERS THERMISTOR DATA POINTS.( CONNECTED BY DASHED LINES) O JULY 11, 1978 ❑ AUGUST 10,197E o AUGUST 23,1978 • OCTOBER 25 B 26. 1978 0 NOVEMBER 29 B 30,1978 NOTES I. LOCATION OF BORINGS SHOWN ON FIGURES 5.1a,5.lb AND 6.40. 2, THERMISTOR STRINGS MANUFACTURED BY INSTRUMENTATION SERVICES IN FAIRBANKS, ALASKA. 3, BORINGS BH-3, BH-6 ARE PERMANENT MULTI -POINT THERMISTOR STRINGS WITH TWO THERMISTORS AT EACH READING POINT. DATA FOR TWO POINTS IS AVERAGED. ALL OTHER BORINGS ARE PVC PIPE, CAPPED AND FILLED WITH ANTIFREEZE (ETHYLENE GLYCOL) MIXTURE. READINGS TAKEN WITH A THERMISTOR CABLE FITTED WITH REDUNDANT ( SINGLE PRIOR TO 19011 THERMISTOR. 4. THERMISTOR READOUT BOX-KEITHLEY 172 A, USED FOR 1980 THRU 1902 READINGS. 5. TOP OF ROCK ELEVATIONS SHOWN ONLY WHEN ENCOUNTERED. 6. BORINGS ARE VERTICAL UNLESS A DIP IS SHOWN, -3 -2 -1 0 1 2 310 SCALE 27 28 29 30 31 32 33 34 35 36 37 'F FIGURE 6,27 ��"�� TEMPERATURE (°C) -3 -2 -1 0 1 2 3 4 1950.9 0 1941.4 1920 40 1900 r w Iss0 v r w w _ 0 80 r r a w I860 3 J W p F 1840 r a 0 120 1820 WOO IGO DH-12 TEMPERATURE (°C) TEMPERATURE (°C) .3 -2 -f 0 1 2 3 4 -3 -2 -1 0 1 2 3 4 1480.0 0 1460 r w LL 40 1440 0 x z O W d 14PO x z ra o wo 80 a 1408.7 w J w €400 1380 120 1360 €60 NOTE- I FLUID WAS FROZEN IN PIPE AT 1.5 FEET FOR ATTEMPTED READING ON DEC, 15,1981. DH-21 TEMPERATURE (°C) TEMPERATURE ("C) -3 -2 -1 0 1 2 3 4 -3 -2 -1 0 1 2 3 4 cw.t ;Mw - I I. ... _ 2044,9 0 2054.5 — -.--�_—.. .—.._.—.. 2040 2040 STICK UP- €.0 FEET (1978) 2020 2020 40 �. 40 w w 4 w w2000 2000 w w Jo i w w O o 1960 z 60 ICI 2 z 80 z 7 0 y P � = J 1980 z w a w r 1960 o a 0 1940 120 1960 120 1920 1940 1900 160 -_--_-..... 160 195L5 0 1946.6 1940 40 1920 f w F- w w LL �- w 1900 z y 80 a > W 0 d J W 1880 0 120 1860 1840 � f60 DH-23 TEMPERATURE (°C) -3 -2 -1 0 1 2 3 4 1971.0 O 1961.8 STICK UP- 1.0 FEET t940 1978) 4Q 40 1920 r � w 1900 0 o x 80' ¢ 3 0 w 1880 J x w � ! 1860 120 g 1840 Is2D 160 DH-24 DH-25 DH-28 WATANA THERMISTOR DATA DAM SITE SHEET 2 OF 2 -3 -2 -1 0 1 2 3.Cl SCALE 27 28 29 30 31 32 33 34 35 36 37 F FIGURE 6.27 ACRES TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE ('Cl 2339,E 0 2)72.0 0 2229.1 0 _... 2220----'o- 2160 11 2320 STICK UP- �' STICK UP - STICK ET 4 , W (1978)2.8 ET 39 FEET 2200 (192. FEET 2(40 (1978} � (1976) .¢ w b 4 w 2300 40 40 40 (� F d 2120 2160 O 4 a # Q 4 w 2280 o Q 2160 Q 4 4 w 2100 d 0 226U 80 60 {¢ 60 4 ,4 b 2140 4 2080 d 22400- o p DR-14 2060 j 2120 A LL €20 Izo Q w w 2100 a II v 2040 z o 4 TEMPERATURE (°C1 z 4 # 4 I 0 1 2 3 4 a o 2060 2151.4 0 w o w a o a_ J 2020 = J = 4 -0 w H w H 2140 I60 w 160 4tj STICK 2000 2060 § 4 H 3,0 FEET r 2120 LL (1978) & b W w 2o40 4 4 LL 40 -1 1980 a 0 2100 z 200 200 4 2096-4 O 2020 j 0 � x �1 I96o ❑ � 4 ii w 2060 60 1941.0 2000 Q R 2060 240 240 1980 1920 4 DR-19 b b ❑ 1900 19sa 260L - 260 --- TEMPERATURE ("C) DR-16 DR-22 -1 0 1 2 3 4 2294.7 zzso STICK UP 4-0 FEET' w 0978) w w 2260 w w AO C, O z 2240 o O w F O -3 -2 -I 0 l 2 3"C a b SCALE 2220 o 60 O 27 28 29 30 31 32 33 34 35 36 37 "F O 2200 DR-26 NOTE TWO SETS OF OCT. 26, 1978 READINGS WERE TAKEN ON TWO DIFFERENT DIAMETER PROBES (DOTS WITH DASHED LINES). WATA N A THERMISTOR DATA -RELICT CHANNEL SHEET I OF 2 FIGURE 6.28 ����5 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 2 3 ^2 -I 0 1 2 3 -2 -( 0 1 2 3 2221.E 2262.9 p 2242.9 0---- 0------- -- -----------� �------------ice., 2200 w 20 2240 w 20 20 2220 F w w w W v � k w Ld 2180 0 40 w 2220 0 40 2200 _ 40 z = z z o = ; z r 0 H 0 r 3 60 1 o 60 60 � � 2160 x 2200 r 2160 w a w LL w F a w w W 0 0 0 2140 80 2180 B0 2160 80 STICK UP-3.5 FEET STICK UP-2.6 FEET STICK UP-1.9 FEET 100 (DEC.,(981I 100 (DEC.,1981) (DEC., 1981) 100 AH-D5 AH-D6 AH-D7 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) -2 -1 0 1 2 3 -2 -1 0 1 2 3 - -2 -1 0 1 2 3 2276.1 0 2319,1 0 2357.E p 2260 - 2340 20 2300 20 20 LLL w w w _ LL W 2240 w r 2280 w LLL k 40 W w 40 LL 2320 40 O LL z z x z 2 O z z O z 2 2220 O 3 F 3 w o 60 j 2260 p 60 w 2300 0 60 J x W W W W 22D0 � BO 2240 � gp 2260 � BO STICK UP-3.7 FEET bs, TICK UP -4.7 FFET STICK UP-1,0 FEET 100 2220 100 1980 (DEC.,1981) EC.,19B1) 2260 100 (DEC.,1981) - AH-D8 AH-D9 AH-D10 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) -2 -1 0 1 2 3 -2 -1 0 1 2 3 -2 -1 0 1 2 3 2358.0 p 0 2272.7 0 2260 2340 20 2320 _ 20 r.1 _ 20 w W W w w v 2240 W 2320 J 40 w 2300 J 40 W 40 0 0 0 x z z z z x H ; # F 2220 3 w 2300 0 60 i 2260 ap 60 } a 60 w -1 0 1 2 3 °C LL w F- W SCALE o w 2200 w 2280 S0 2260 80 80 27 26 29 30 31 32 33 34 35 36 37 °F STICK UP-3.1 FEET STICK UP-4.0 FEET 1980 STICK UP- 3.5 FEET 2260 100 100 (DEC.,19B1) 2240 (DEC„1981} 100 (DEC.,1981) AH-DII AH-DI2 AH-D14 WATA N A THERMISTOR DATA - RELICT CHANNEL SHEET 2 OF 2 FIGURE 6.28 �il� TEMPERATURE ('C) -3 -2 -1 0 I 2 3 2127.5 0 2120-- 20 2100 r w k J 40 0 2080 z r LW o 60 w 2060 a 0 80 2040 STICK UP-0.0 FEET (OEC.,1981) 100 AH-HI TEMPERATURE (°C) -3 -2 -1 0 1 2 3 1970.9 0 R� 1960 20 r 1940 w w 40 0 0 1920 z 0 sa w J 2 w 1900 w a 80 IBBO STICK UP-4.O FEET (JAN..1982) 100 AH- H2 2188.4 -3 0 TEMPERATURE -2 -1 (°C) 0 1 2 3 2093.5 -3 0 TEMPERATURE -2 -1 (°C) 0 I 2 3 2180 ______ �_�i ------- 202080 f � za 2160 LL _ r w r F 2060 .ww.. wLu w 40 w w 40 O LL 0 of 2140 r 3 2040 z 3 0 60 w S 60 J w 2120 = a J w 0 2020 q 80 BO 2100 STICK UP•3.5 FEET 2000 STICK UP-3.0 FEET 100 (JAN.,1982) 100 (JAN.,1982) AH-H7 TEMPERATURE (°C) -3 -2 -1 0 1 2 3 2245.7 0 2240 20 2220 w w r w 40 z 2200 0 0 z w a 60 w 1980 r a w 0 BO 1960 100 AP-8 _ a2 AH-H8 BORROW SITE H BORROW SITE 0 TEMPERATURE 00 -3 -2 -1 0 1 2 3 2295.8 0 2280 _ 20 w w 2260 u w 40 z 0 o Z 2240 # w d 60 J 2 w a w 2220 0 80 STICK UP-3.2 FEET 200a (1978) 100 AP-9 WATAN A THERMISTOR DATA - BORROW SITE H Ek BORROW SITE D TEMPERATURE (°C) 0 1 2 3 20T9.6 2060 20 r w r LL w 2040 J 40 0 z = 0 z r # w 2020 S 60 J 2 w 0 20011 80 1960 100 - STICK UP-4.0 FEET (JAN.,1982) AH-H3 -3 -2 -1 0 1 2 3eCI SCALE 27 28 29 30 31 32 33 34 35 36 37 F FIGURE 6.29 A1:1S WATANA EMERGENCY DAMSITE SPILLWAY SITE GENERAL VIEW OF INLET AREA & WESTERN HALF OF OUTLET ZONE ARTISTS SKETCH WATANA RELICT CHANNEL PHOTOS SHORTEST FLOW PATH APPROXIMATE EMERGENCY SPILLWAY SITE LEGEND CONTACTS1 ...." APPROXIMATE NORMAL MAXIMUM OPERATING LEVEL, EL.2185'. POSSIBLE FLOW PATH IF SEDIMENTS ARE PERMEABLE. A IMATE .G NOTES �N 1. RELICT CHANNEL PROFILES SHOWN ON FIGURES 6.31 AND 6.33 2, PHOTO LOCATIONS B RELICT CHANNEL TOP OF ROCK SHOWN ON FIGURES 6.30 AND 6.35 3. PHOTOS TAKEN SUMMER 1990(LEFT) B SUMMER 1981 (RIGHT). 4. RIGHT PHOTO LOOKS DOWN SHORTEST POTENTIAL FLOW PATH. CLEARED SPOT NEAR CENTER OF PHOTO IS TOPOGRAPHIC LOW, EL, 2200 FEET, PHOTO LOCATION SHOWN ON LEFT PHOTO, S5, ARTISTS SKETCH LOOKS OPPOSITE DIRECTION OF RIGHT PHOTO, FIGURE 6.30 z J 2500 a If _ 2300 4 2100 a w w J w 1900 1700 50+0 044® AZIMUTH _� OF SECTION 224' LOOKING TOWARDS WATANA RESERVOIR DR-22 PROJECTED —45' N-W,- ,W-17 ............I ................. EO.BOF �SILTY,SAND W/SOi�44F�RS_�GLACIAL_DUTWASHt OH SILTY SANO (ALLUVIUM)' 6,500 FPS ~ _ O SANDY GRAVEL (ALLUVIUM I 14, MO FPS K SANDY GRAVE ALLUVIUM) OBOULDERY GRAVEL{ALLUVIUM) QUARTZ DIORITE- ) I I 0 45+00 40+00 35+00 DR-20 PROJECTED FPS — 21V S-E- .�9�!I:LL�I�S�1,LfI�SA�'I�il�j G ..�.:....t1.1ti...':.....1@&(D'SILTY SANO(GLACI -SILTY BOULDERY SAND (TILL) 6�FPS �:J (JH SANDY GRAVEL;ALL Q 8,500-9,DOD F� ��� _ J O SAND (TILL) CLAYEY SILTY BOULDERY SILTY SAND(TILL) OJ DIORITE , SHEAR 15,000 FPS 14,500 FPS I I I I 30+00 25+00 20+00 15+00 12,000 FPS I 10+00 TO WATANA EMERGENCY SPILLWAY AND DAM 2500 DM A- ss W-IG 2300 lY SILT AND SILTY"" t (LAKE DEPOSIT) G 2100 t S4NDY GRAVEIL L} I 16,000 FPS 1900 1700 5+00 0+00 m w ? 044® AZIMUTH c __ OF SECTION 224 LOOKING TOWARDS WATANA RESERVOIR w 2500 g z J DR-27 DR-€3 2500 ............... PROJECTED PROJECTED DR-26 2300 • ' C • _ .................. "•' G SILTY SAND (OU ASH 1 p f GRAVELLY TW - '�OJECSEE ^, I� 1 1,8 D FP 5.... 2,450 FPS .....,. .. .............................. 4200 FPS ............... .. 5,6D0 FPS COBBLES WITH SANDY RAVELLY SILT E 8 F H F 81500FP5 3 350 FP5 rc�............. �...�y _...........----.... . SAND L.FIVS,ESR t S IGLACSAL OU7WASN1 Orr 7,400 FPS . .......... FPS G ' CLAYE'1' SILT(LAKEDEPOSIT} - GRAVELLY SILT" SANDY GRAVEL I ALLUVIUM �.`'`1G `ACIAL OUTIA SH)�`JalJy 2300 ~ ��.....s,....z............. H f4,OD0 FPS ��""' L BOUL E{iY SANDED z 2100 g --"--- VARIED SILTY I5,OD0 FPS 5. CLAY i LAKE qND )LAY SAND €4,250 FPS �I�I�h € 2100 F 1 DEPOSIT )O (TILLIO w 1900 1900 1700 1 I 100+00 95+00 90+00 85+00 80+00 75+00 7C+00 65+00 I 60+00 55+00 50+00 1700 2700 SECTION CONTINUES TO STATION 220+00 OOI'--a AZIMUTH Y IBI, r z 0 a z m GROUND B BEDROCK SURFACE RISING OF SECTION z w 2700 LOOKING TOWARDS WATANA RESERVOIR r' 2500 DM-A� 224" _ 001°t- DM -B w w (,200 FPS ¢I 2500 .. z 2300 .......................... ..... ...................... .................. ....-. .. ............... ........ .... .... ... ..... .... ...... ......... .. ... ... 1,200 � � —� — ~ ~�L��"� FPS 5,500 FPS 1,300 FPS 6, BOO FPS 7,IGOFPS 1 2300 w 2100 _ 2,600 FPS _--� 7.300FPS ... ....... ..... . 15,500 FPS ... ...........�6i0�.�r�}�.i...� ti=y _.s*� Li*a,.a�Y� v�-1t-.-.u.r.k...,.,.-tc.: ............�. :�-. .. �..... Y ti " ~14,000 ~ � FPS 2100 1900 I 1 I 3 I 150+00 145+00 140+00 1 I 135+00 130+00 125+00 120+00 U5+00 1 I I 110+00 105+00 100+00 1900 REFERENCE, DAMES & MOORE, 1975. CO E, 1979. WATANA RELICT CHANNEL SECTION LEGEND LITHOLOGY : wIMW9 BEDROCK (INFERRED TO BE DIORITE) OOVERBURDEN, STRAT€GRAPHIC UNITS AS SHOWN CONTACTS ----- APPROXIMATE TOP OF ROCK ...... NORMAL MAXIMUM OPERATING LEVEL EL. 2185 BOREHOLE$ I DR-20 GO STRATIGRAPHY - DR-20 COE ROTARY DRILL BORING GEOPHYSICAL SURVEYS: Q DM -A SEISMIC REFRACTION SURVEY END OR TURNING I POINT-1975, DAMES 9 MOORE ^^ SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND FPS OTHER: W;16 INTERSECTION WITH CROSS SECTION W-16 NOTES I. SECTIONS READ FROM TOP TO LOWER LEFT ( STA. 0+00 TO 150+00) SEISMIC LINES DM -A B B 2. SECTION LOCATION SHOWN ON FIGURE 6,35. 3. SECTIONS W-16 8 W-17 SHOWN ON FIGURE6.35. 4. VERTICAL AND HORIZONTAL SCALE EQUAL, 5. SECTION ELEVATIONS FROM COE I" = 200' TOPOGRAPHY, 197B. 6. SECTION COINCIDES CLOSELY WITH DIVIDE BETWEEN SUSITNA RIVER AND TSUSENA CREEK DRAINAGES. THIS SECTION REPRESENTS NARROWEST RELICT CHANNEL WIDTH WHERE GROUND SURFACE IS ABOVE MAXIMUM POOL ELEVATION. 7. SECTION LIES ON DAMES AND MOORE SEISMIC LINE DM -A AND DM-B, 1975, B. SEISMIC LINE ELEVATIONS CORRECTED AS PER COE SURVEY AND NPAS AIR PHOTO MAPS, 197E. 9. REFER TO TABLE GA FOR SEISMIC VELOCITY AND MATERIAL CORRELATION. 10. SEE FIGURE 6.32 FOR STRAT€GRAPHIC COLUMN AND GENERAL NOTES. O 200 400 FEET SCALE FIGURE 6.31 L�CRlSi 0 o o o 0 0 0 C O o 0 0 0 O m d N O O O N N O N rD w w W w ti ti r w w w N 3,230,000 N F W W z N W W N� W Z -J 2 U F 4 g A H-D5 D C N 3,232,000 O AH-D7 F �. IDR-22 - f �1t xyy�f A D8 _ 7 ��rF{lv;r o O F - N 3,234,000.i5'lt. - - »' DR 26wr F - - - - - - -- AH D9 " _. _. ". """_- "- x .efex 'Sti .(: lnR .k, r�` �"��,:�_;: O i.%�^�=�"�• " " " _ e 1.� i:'.. .:;:. :u 2 Y'! rr'O �_ :.`�Yfi 'S'. Ff•i.+r. :a ( z eH '.'.H:'F .r�l'L�:.n l�.o. m.r£:w nrm .a o 13 7 .. :Had . . r e., z � y. .aaa . � r - _ : ��:�a . ..a... . 1 . . yaw, ?x •Rr .r . r� �� � - - . x:ry:.. crfhlt�tm:. `W.:a.,�n„'%y. •"`�`.aaaz" �?� Yaaox .aazeezr'aga'+tia�' R.. _, x o-lr.r �. ref = F R R. dt' .zL a s wa.'eiia. z' r a ti-4iv5T' fi _- ,;Yze,. D �.7. - r..G.t.1.,.: ...F+. aa.„�a: -.a:'.W A.x 1. :-'Ai...: /•.�a.a.- .,..� .. i. .kt:t.� �.�f.. a. x.. zr aa• 2 3 - ..a�. - �:s;. ,.:, . 1FAr!..� f as',`:,Ta?'•¢a AH-DI4 AP F yF � .,x. 13 E fi7''+rvrer2ti�, AH-DI2 N3,236,000 - F ' z AH-DII AH-DICI 9 Y } 9 2 Rom _-,`-. 0 20 40 FEET -VERTICAL F s r - - �� � '� - • � SCALE s 0 400 800 FEET HORIZONTAL SCALE N 3,238,000 -- �oa WJET N A CONTINUES TO ra e-��tl�°1 493.6 FEET RELICT CHANNEL a BORROW SITE I] STRATIGRAPHIC FENCE DIAGRAM SHEET I OF 2 FIGURE 6,32 ����� 0 o 0 0 a 0 0 ti W W W D R-19 N 3,230,000 GENERALIZED STRATIGRAPHIC COLUMN BORROW SITE D AND RELICT CHANNEL COLUMN UNIT - SURFICIAL C OUTWASH D ALLUVIUM B FLUVIAL DEPOSITS E OUTWASH Bd F ESTIMATED DESCRIPTION: THICKNESS: 0-6, BOULDERS, ORGANIC SILTS AND SANDS. 0-1B' [2' AVERAGE 0-15, 0 _ 35' WAVERAGE G TILL/WATERLAIN 2-50, TILL 12' AVERAGE E :O DR-16 E ii?,i H ALLUVIUM 0-40' N323 2 00 I ................ �"" F DR 22 - == I TELL lo' TO 65' = - - - -- - - 20'AVERAGE - ALLUVIUM oX. K ALLUVIUM TO 160` N 3,234,000 N 3,236,000 N 3,238,000 T� BEDROCK,DIORITE SILTY SAND WITH SOME GRAVEL AND OCCASIONAL COBBLES. USUALLY BROWN,BECOMES GRAY IN LIMITED AREAS. THICKEST IN NORTHERN PORTIONS OF AREA.THINNiNG SOUTHWARD,OFTEN ABSENT NEAR SUSITNA RIVER. SAND WITH SOME SILT, OCCASIONAL GRAVEL. GENERALLY BROWN, FOUND ONLY ALONG COURSE OF LIMITED DRAINAGE CHANNELS FORMED IN OUTWASH E. GENERALLY SORTED, SAND, SILT, GRAVEL AND COBBLES,PARTLY SORTED, WITH FRAGMENTS SUB -ANGULAR TO ROUNDED, SILT AND SAND LENSES OFTEN PRESENT. BROWN TO GRAY BROWN WITH A COBBLE/BOULDER ZONE OFTEN PRESENT AT THE BASE OF UNIT F. CONTACT BETWEEN E a F IS OFTEN POORLY DEFINED. CLAYEY, SILTY SAND, USUALLY GRAY, OFTEN PLASTIC. CONTAINS COBBLES AND GRAVEL IN MANY AREAS. OCCASIONALLY PRESENT AS A LACUSTRINE DEPOSIT SHOWING LAMINATIONS AND/OR VARVES. GENERALLY A TILL DEPOSITED THROUGH OR NEAR STANDING WATER. SAND,SILT, GRAVEL, PARTLY TO WELL SORTED, OFTEN ABSENT BETWEEN UNITS G 0, T . UNIT REPRESENTS PERIOD OF MELTING PRODUCING ALLUVIUM /OUTWASH BETWEEN THESE DEPOSITS. APPEARS AS NARROW BANDS REPRESENTING CHANNEL FILLINGS. THICKEST IN WESTERN PORTION OF THE AREA. POORLY SORTED SAND, SILT, GRAVEL AND COBBLES, OCCASIONALLY WITH CLAY. GENERALLY GRAY TO GRAY BROWN. CONTINUITY UNCERTAIN DUE TO LACK OF INFORMATION AT DEPTH. SILT OR SAND LAYER 2INCNES-6INCHES THICK OFTEN FOUND IN CENTER OF UNIT T. BASE UNIT ON TOP OF BEDROCK, EXCEPT IN BURIED CHANNELTHALWEG. CONTACT BETWEEN T B, J OFTEN POORLY DEFINED, AND LOCALLY INCLUDES AN ALLUVIUM DESIGNATED J' SAND, GRAVEL,C OBBL ES,BOU LDERS, FEW FINES, PERMEABLE. FOUND ONLY IN THALWEG OF BURIED CHANNEL, TOP AT 292 FEET,EXTENDING TO ROCK AT 454 FEET IN DEPTH IN DR-22. NOTES I. EXPLORATION LOCATIONS SHOWN ON FIGURES 5.1 AND 6.40. 2. FOR LEGEND OF SYMBOLS SEE FIGURE 6.33 3. EXPANDED SECTION FROM DR-13 THROUGH DR-20 SHOWN ON FIGURE 6.33. 4. LETTERS USED TO DEFINE UNITS ARE ARBITRARY AND WERE USED FOR CORRELATION PURPOSES. 5. THE ACCURACY AND THICKNESS OF SOIL AND ROCK STRATA IS SUBJECT TO VERIFICATION. 6. THIS FIGURE IS GENERALIZED FOR GRAPHIC PRESENTATION. FOR MORE SPECIFIC INFORMATION REFER TO TEXT AND BORING LOGS, WATA N A RELICT CHANNEL & SORROW SITED STRATIGRAPHIC FENCE DIAGRAM SHEET 2 OF 2 0 20 40 FEET -VERTICAL SCALE 0 -400 BOO FEET -HORIZONTAL SCALE FIGURE 6.32 2400 2300 2200 r w LLLj 2100 1900 MOD ITOO ~045* AZIMUTH ,� 225, OF SECTION WATAN A RELICT CHANNEL -EXPANDED THALWEG SECTION LEGEND LITHOLOGY : C z E'F J' LM G J CONTACTS: KNOWN UNIT CONTACT —'-- INFERRED UNIT BOUNDARY CIF BEDROCK SURFACE WHERE DRILLED. "I--- NORMAL MAXIMUM OPERATING LEVEL EL.2185 BOREHOLE$; DR-26 COE ROTARY CORE BORINGS 1:1- NOTED AS FROZEN DURING DRILLING 2400 NOTES I. SEE FIGURE 6.32 FOR STRATIGRAPHIC COLUMN AND GENERAL NOTES, 2. SEE FIGURE 6.31 FOR TRUE SCALE SECTION OF SAME 2300 GENERAL AREA. 3, VERTICAL TO HORIZONTAL SCALES 5- I, 4, PERMAFROST DATA (TEMPERATURE. PLOTS ON FIGURE 6.281. 2200 DR-13 NO TEMPERATURE DATA DR-20 NO PERMAFROST DR-22 FROZEN 72' TO 110' DR-26 FROZEN 19' TO 55' • DR-27 FROZEN 0' Tp 44' 2100 5. BEDROCK ELEVATIONS BASED ON SEISMIC REFRACTION. DATA (FIG, 5,1) 6. THE ACCURACY AND THICKNESS OF SOIL AND ROCK STRATA IS SUBJECT TO VERIFICATION. 2000 7 TH€S FIGURE IS GENERALIZED FOR GRAPHIC PRESENTA- TION. FOR MORE SPECIFIC INFORMATION REFER TO TEXT AND BORING LDGS, 1900 IBoo 1700 0 80 160 FEET VERTICAL SCALE 0 400 800 FEET HORIZONTAL SCALE FIGURE 6.33 ���� 2400 F- W a 2000 0 F- i 1600 J w 1200 2400 330° 150" AZIMUTH _ OF SECTION�286° OM Q-A SL W-16 NORMAL MAXIMUM SW-3 SL SO-2 - NORMAL MAXIMUM OPERATING OPERATING POOL EDGE 4 _LEVEL EL.2185 _ I DR-22 106* — AZIMUTH ,3I5' OF SECTION t 135' SL 80-I SUSITNA RIVER _ —1 KING DOWNSTREAM)�`-..---�-- THIS AREA APPROXIMATELY 9000' UPSTREAM OF WATANA DAM CENTERLINE SUSITNA RIVER TO TSUSENA CREEK ESTIMATED THALWEG ( DEEPEST PATH ) SECTION W- 17 315 ° F w 2000 o SUSITNA RIVER a (LOOKING DOWNS7REF w 1600 w EL. 1470± 1200 SW-3 NORMAL MAXIMUM OPERATING LEVEL EL.2185 DR-19 THIS AREA APPROXIMATELY 3000' UPSTREAM OF WATANA DAM CENTERLINE "THE FINS" DM -A SL 80-2 1 35 ° NORMAL MAXIMUM SL 80- I OPERATING POOL EDGE DR-20 DR-18 4 TSUSENA CREEK EL. 1680 "THE FINS" TO TSUSENA CREEK SHORTEST FLOW PATH SECTION W- 16 WATANA RELICT CHANNEL PROFILES 2400 2000 160 0 2400 TSUSENA CREEK EL.1680 2000 1600 1200 LEGEND CONTACTS: -----' APPROXIMATE TOP OF ROCK GEOPHYSICAL SURVEYS QSW-1 ENTERSECTION WITH SEISMIC REFRACTION LINE DM-C 1975, DAMES & MOORE SW-1 197B, SHANNON H WIL50N SL 60-I 1980, WOODWARD-CLYDE CONSULTANTS SL81-2 1981, WDODWARD-CLYDE CONSULTANTS BOREHOLES1 DR-19 COE ROTARY DRILL BORING 1200 NOTES I. PROFILE AND SEISMIC LINE LOCATIONS SHOWN ON FIGURE 6.35 , 2. SECTION ALONG DM -A SHOWN ON FIGURE 6.31. 3. VERTICAL AND HORIZONTAL SCALE EQUAL. 4 SURFACE PROFILE FROM 1"=200`TOPOGRAPHY, COE 1978 TOPOGRAPHY GENERALIZED TO 125 FEET, 5. TOP OF ROCK NORTHWEST OF SL 80-1 IS PROJECTED UP TO 300 FEET TO PORTRAY ACTUAL THALWEG PROFILE. 0 400 800 FEET SCALE FIGURE 6.34 CIN jC GOLD ��PEFR 41 / LOCATION M0 4 B MILES AP SCALE (fir - --. E - ' LEGEND s - TOP OF BEDROCK, COET NTOURINT INTERVAL 50 FEET, --, .- - .--.,- DASHED, 50 FOOT CONTOURS AS .---� "------' - ` --- --- ;' .,...'.s "-------"--- TOPOGRAPHY, CONTOUR INTERVAL 100FEET. a` f 1 - .._�. ! - ..f4fi nip-�� ... j} ._.. / , • v v w "rl-d ,� �,�,�-�Ak �' 1 G � � IL �kBoo- n ! O 2200- _ 2200� Tom. ! s i } I DM -A a 8 iv , POTENTIAL CHANNEL THALWEGS s P - - � W-16 W-I6PROFU_E OR CROSS-SECTION LOCATION (SEE -- t NOTES I AND 2 ) 1"soa 2000. _ 2ti4° 1 NOTES 1. SECTION DM -A AND B SHOWN ON FIGURE 6.31, as 11 I 150 ' ' 2- PROFILES W-I6 AND W-17 SHOWN ON FIGURE 6.3a. 23D0 �i1. - !s . %3. DETAILED STRATIGRAPHIC FENCE DIAGRAM SHOWN ON / - FIGURE 6.32. _ ._> 4 �� q 1 ! "f H TAILED SEISMIC LINE SECTIONS SHOWN 1N APPENDICES r ` 5. RELICT CHANNEL PHOTOS SHOWN ON FIGURE 6.30. 1900 y 1 � g00p { + 1V - a - '- TM '_ CE N _"._ p looa zpo0 FEET SCALE 6 t WATANA RELICT CHANNEL -TOP OF BEDROCK FIGURE 6.35 ��II� w 1 r4 -%"a, x')00 I N 5,220,000 I m 3'mono IN 3,224,000 3 0 n.� z> r 2600 w % w 2500 w z 0 r= 2400 w w W 2300 WATANA QUARRY A PLAN QUARRY SITE A PLAN AND SECTIONS REFERENCE iI"= 200' TOPOGRAPHY 1978 COE,INPASISHEET 8/26. 1" 400' TOPOGRAPHY 19BI AAI, (NPAS) SHEET I OF I, FLT. NO.4-4. 2600 w w 2500 z 0 H 2400 Irl 2300 00 ®_ AZIMUTH _� ISo° OF SECTION ANDESITE PORPHYRY B DIORITE SECTION D-D AZIMUTH 0" ��OF SECTION—� leo° ANDESITE PORPHYRY R DIORITE ! \ r SECTION G - G LEGEND STRUCTURE ® SUSPECTED FRACTURE ZONE WITH LOCAL SHEARING i, i0M BEDROCK OUTCROP mSHEAR ZONE CONTACTS ---MAPPED LIMIT OF BORROW SITE OTHER D D CROSS-SECTION LOCATIONS SAMPLE LOCATION (APPROXIMATE) NOTES I. SELECTED TYPICAL SECTIONS SHOWN. 2. VERTICAL SCALE 4 TIMES HORIZONTAL SCALE. 3, 50 FOOT CONTOURS REPRODUCED FROM REFERENCED BASE MAP. 4. CONTOUR INTERVAL 50 FEET 5. QUARRY SITE LIMITS BASED ON PRELIMINARY MAPPING AND 15 SUBJECT TO RESULTS OF DESIGN EXPLORATIONS. G. INTERPRETATION BASED ON AIR PHOTO INTERPRETATION AND RECONNAISSANCE, AND SURFICIAL GEOLOGY MAPPING. 7, PHOTO TAKEN AUGUST, 1981, B. LITHOLOGY AND CONTACTS WITHIN QUARRY A REQUIRE FUTURE DELINEATION 0 400 600 FEET SCALE FIGURE 6.37 ACRES j N � 0I nl �- f ✓'f , W ` € _ PHYLLtTEf�� p{ORITF - PHYLLITE f, I RITE cz � DIORITE fs � \ . _ � ;f i• rciw.% .. J lr � 1 ��.5',�43 —1 ! CLIFFS . r 1, � r - J (� - .._CONGLOMERATE. i . f - .... ...DIORITE � �i �', /�' t Jf; ,' ,'/' c € € i` i ! �` : � 1, : i J1( ..,\\ � _ ..--- -- r, � f � \, � •1 / � / r f �� I r� � COO •' '- / J 7 �� v � ' �f•%i�. _ ._ �\. 'fir 'I I r/I 'i%.��i..°' F f I 1 !I �� '-- \\ __\`#?i•,F'7 k--- _ BASALT l SCATTRE Ef\.� p ` \ DIORITE \ r - Li� OUTCROPS �� \/ ♦ --..-- ---- ' - � _.. - �T ! � � r /� 1` DIORITE -._.... , J \\i,k1 ;\�\ ; i:•kf F�1/ .. �:'�\� r%\\` ..IsquC7-" l � _ } ,J r i t3t117 \ N3,237,OGp,_.• i REFERENCES: BASE MAP FROM COE,1978—1"=200' WATANA TOPOGRAPHY, SHEETS 14 a 15 OF 26, COORD)NATEs IN FEET, ALASKA STATE PLANE (ZONE 4). LEGEND CONTACTS: — QUARRY SITE LIMITS -- BEDROCK OUTCROPS GEOPHYSICAL SURVEYS: @SI. CI 8 SEISMIC REFRACTION SURVEY END OR TURNING POINT - 1980 - 81, WOODWARD -CLYDE CONSULTANTS •• SEISMIC VELOCITY CHANGE FPS SSEISMIC VELOCITY IN FEET PER SECOND NOTES I. SECTION LOCATION SHOWN ON PLAN. 2. QUARRY SITE IS SHOWN ON LEFT HAND PHOTO,FIGURE 6,30 3. CONTOUR INYERYAL 25' TRACED FROM REFERENCED BASE MAP. 4. SECTION LIES ON SEISMIC LINE SL80-6 (APPENDIX H, FIGURE ID)• 5. QUARRY SITE B L.IMITS BASED ON QUARRY SITE LIMITS PROPOSED BY COE,1978. LIMITS OF ROCK OUT CROP MAPPED BY COE, 6_ QUARRY MATERIAL IS DIORITE OUTCROPS WITH SOME PHYLLITE, CONGLOMERATE AND BASALT AT LOWER ELEVATIONS. OVERBURDEN IS TILL AND OUTWASH,SEE BORROW SITE D, FIGURE 6.40. 7. ENTIRE QUARRY SITE LIES WITHIN PROPOSED RESERVOIR LIMITS. 8. SEISMIC REFRACTION DATA SHOWN IN APPENDIXES H AND T. 9. REFER TO TABLE 6.1 FOR SEISMIC VELOCITY AND MATERIAL CORRELATION. SLBI-19 AZIMUTH OF SECTION 2300 2300 2300 2200 ....... ............................... 1,600 F P S 1,350 FPS 2200 F 2100 5,000FPS�"•.••..•••' 2100 w'•'" 2000 .. I,600FP5 7000FPS •' 0 200 400 FEET 0 1900 TO SUSITNA RIVER 2000 SCALE B,400 FPS -�+ w 1800 9,000 FPS `\�� 1800 I700 \��_� g000FPS �— 123,000FPS 1700 1600 12,500FPS — ----------- 1600 16,500 FPS SECTION SL80-8 WATANA QUARRY SITE B PLAN AND SECTIONS FIGURE 6.38 ��RE� S m o H a z 1~ 7Ab,000 5W-9 7PU7 Tf SU9ENq -� �. BORROW �s�I,Te c...-�� �Fk BORROW SITE C REFERENCE: BASE MAP FROM USGS €:83,360 ALASKA QUAD RANGLE,TALKEETNA MOUNTAINS (D•3) COE,19TS SSW, 1978 COORDINATES IN FEET, ALASKA STATE PLANE (ZONE 4) o M1 i] 01 -..� TSUsENA BUTTE B BROW SITE F'`, PHO (LEFTOT} P-5 Y�9 TXk �l .. \�R-2-S LOWER BORROW SITE F UPPER BORROW SITE F WATA N A BORROW SITES C a F PIT LEGEND --- MATERIAL LIMITS BOREHOLES AND TEST PITS ' TP-6 1978, COE TEST PITS AND TRENCHES GEOPHYSICAL SURVEYS! A SW-9 SEISMIC REFRACTION SURVEY END OR TURNING POINT-1978, SHANNON S W€LSON NOTES I, CONTOUR INTERVAL 500,TRACED FROM ENLARGED REFERENCED BASE MAP, 2. BORROW SITE LIMITS BASED ON SEISMIC AND AIR PHOTO INTERPRETATION. FINAL MAPPED LIMITS OF BORROW MATERIALS, SUBJECT TO RESULTS OF DESIGN INVESTIGATIONS. 3. BORROW MATERIAL IS COMPRISED OF CLARK AND TSUSENA CREEK HISTORICAL AND RECENT TERRACE DEPOSITS OF GRAVEL AND SAND. 4. ENTIRE BORROW SITE LIMITS LIE OUTSIDE OF PROPOSED RESERVOIR LIMITS. 5, EXPLORATION LOGS AND SEISMIC LINE SECTIONS IN COE, 1978, S. SEISMIC LINE LOCATIONS REPLOTTED FROM SHANNON IN WILSON,1978 LOCATIONS APPROXIMATED. 7. PHOTOS TAKEN SUMMER OF 1978 AND 1981. 0 2300 4000 FEET SCALE FIGURE 6,39 ACYIS H 3 23eo N 3,2_s�,onn_ I ROW a3� J. 1-her i 2l; CvFLaYd Lai a _ ( DR Z. fff �. r i` cc�NTCIURs OMITTED 1 i ! `l� t__. �, �r.....__ „T,� _ y,-`/ ,-..__,f ��•• \ ..__ _ J DA zo , FOR CLARITY Ali • i , r- J A p li- C Aki-D-C ~®AP-6 e E k 1 A17, if �'•,, r .€.I, g"— r- • TP-I, fP-8 AP-22 AP -Jo 4P-21 TP-9 D €i 14 f OAP-20 A1'-I'7 e ��^--- REFERENCES BASE MAP FRDM 1978,COE-1"=200' DAMSITE TOPOGRAPHY, SHEETS 13-15,I8--20 OF 26 -D-4 :. AP- _ ...._\ � 7 P-10 i AH-0-3 TP4 - OAH->[l A P-3 AH-D-2 GAH-DJD OAH-D-8 17R-27v %171�-13 , f J i NO-CE:BFISNIIC LJN� EXTENDF-D €I,000 F_,FT TO wRTH FROM w-H WATA N A BORROW SITE D PLAN D-13 LEGEND CONTACTS: ---200 I ' --- BORROW SITE LIMIT — R--- GEOPHYSICAL SURVEYS: SSW-3 SEISMIC REFRACTION SURVEY END OR -TURNING POINT 00„ DM -A 1975, GAMES 9 MOORE SW-3 19T6,-SHANNON & WILSON ' Sl_ 00-0 1980-91, WOODWARD-CLYDE CONSULTANTS l BOREHOLES AND TEST PITS: •°�..:�-'"" -�\ �� OR-27 1978, COE ROTARY DRILL BORING `�� •�'- a ? \ Q AP-2j 1978, COE AUGER BORING 1960,AAI AUGER BORING -) p TP-il 1978, COE BACKHOE TEST PIT C,3 BULK SAMPLE LOCATION NOTES I W.� I. EXPLORATION MAP SHOWN ON FIGURE 5.4a. 2- DETAILED SECTION ON OM -A & B SHOWN ON FIGURE 6.3L % 3. BORROW MATERIAL IS COMPRISED OF UP TO 600 FEET OF GLACIAL TILL, OUTWASH, AND ALLUVIUM. A STRATIGRAPHIC !/ SECTION IS SHOWN ON FIGURE 6.32. 4, CONTOUR INTERVAL 25 FEET, REDUCED AND TRACED FROM REFERENCED BASE MAPS. 5. FOR SURVEY, EXPLORATION AND INTERPRETATION DATA SEE x 22,3 NOTES 7 THRU 12, FIGURE 5.10. SCALE 0 400 800 FEET FIGURE 6.40 ca - 'I iiiiiiiiiiiiii son 1111111:23110118 NMI NIIIIIIIII p wo • • ,=NNW= ummw-wom mm mmmm• LEMON= NMI m MINIMME IMIMMIME Sam mmmm m momIIl� Fjgarkj WWA Mai &M MHOS dot mom mia MEE mmmm�m no ���I■■���■■�.��tRR 1Rl��l er. . !liilr�f!llya9eu xc+�tA.�a:BVs[ his r • .•'. �''r r �.c� :I-P, • � y ��6A�I��rl��•Fv".'�i�#2J%�9��'Y/H'�,'1A��a������ � � Oiii�tl�OQi�:,/•tir..:a:d/b'.:.Q:�,wlr�9ill�S������ ! NOTE: TEST PITS R12 THROUGH RI4 LOCATED ON THESE TWO ISLANDS AND NEXT ISLAND UPSTREAM SHOWN ON PHOTO. N3,226,0Q0-TP-RE4 FLOW 7P-fi 12 \ 34.12�x 75 am T vc%0 N 3,2m000 \ f551 i PHOTO =� 'A ' f ) l i r� /,®TP"E 1 7 V IF5O ' /','/ / O • ;���/!'jr TP-EI4� TP-E 1{ SUSITNA HIVFR c� �a un 6vi I TP-2UM 1 TP-Ego--- ,Fr SW-10 .�-.- TP-E8 l:- "('P-Efin/ �, ; t`/„1 j � � , •f coo �. �, s (I / , � 4 , ._1 /; ��`r--�✓�/� `";� it/ f/f � �//�, f ;' ���''''j j� � �,� i' REFERENCESE BASE MAP FROM COE,197B-1" =200' WATANA TOPOGRAPHY, SHEET 6 911 OF 26 R BM,19BI—I"=400' OEVIL CANYON RESERVOIR MAPPING,FLIGHT 5 (6-B), MANUSCRIPT 2 COORDINATES IN FEET,ALASKA STATE PLANE (ZONE 4) 0 cr` 3x! .. TP-3A �}. AH"E2 TP L6 9 / ,��� TY �E3® !\ ` s AH-E4 `�`� �r� TP-EI7 �� WATA N A BORROW SITE E PLAN SW-14 AH"FI NOTES I. TYPICAL SECTIONS AND PHOTOS ARE SHOWN ON FIGURES 6.44 AND 6.53. P. CONTOUR INTERVAL 25', TRACED AND/OR REDUCED FROM REFERENCED RASE MAPS. 3. "SW" SEISMIC LINE LOCATIONS CORRECTED AS PER S 9 W ORIGINAL SURVEY NOTES, 19BO-81 LOCATIONS PER R 8 M SURVEYS. 4. MATERIAL LIMITS BASED ON FIELD EXPLORATION, MAPPING AND AIR PHOTO INTERPRETATION. FINAL LIMITS OF BORROW MATERIALS SUBJECT TO RESULTS OF DESIGN INVESTIGATIONS. 5. BORROW LIMITS EXTEND TO SOUTH SHORE OF RIVER, AND ADJOIN BORROW SITE I ( FIGURE 6.51) ON WEST ENO. & NORTHERN PORTION OF BORROW SITE EXTENDS ABOVE PROPOSED DEVFL CANYON RESERVOIR LIMITS 11455'). 7. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICES F. H AND 1. LEGEND CONTACTS --- MATERIAL LIMITS BOREHOLES AND TEST PITS OAH-EI 198O, AAI AUGER BORING ®TP-5 1378, COE RACKHOE TEST PIT MTP-F3 1981, AAI BACKHOE TEST PIT TP-RI3 GEOPHYSICAL SURVEYS; ASW-12 SEISMIC REFRACTION SURVEY TURNING OR ENO POINT SW-12 197B, SHANNON & WILSON 91-3O-9 1980-81, WOODWARD-CLYDE CONSULTANTS OTHER: sw-lo sw-lo S CROSS-SECTION LOCATION r (SEE NOTEi) O 400 BOO FEET SCALE P_m�� FIGURE 6.43 2000 F 1800 w w 0 1600 a w w 1400 1200 ROCK HAMMER FOR SCALE 2000 I BOO w QSW-40--da LL I,000 FPS 2,200 FPS z 1600- - Yaao 7 tl�� 00"' w yp pc7,400'no I S4C0 FPSO�2?n'1 1200 TEST PIT TP-E15 SOUTH WALL SHOWING BOULDER LAYER OVER SANDY GRAVEL 003°® AZI MUTH OF SECTION 2,200 FPS 1,000 FPS -r 1,000 -�lTr0 d 400 FPS�4�_ M,370 u�Li�.'auo0 rI3p FPS SECTION SW-10 �Sw-lO 2,200 FPS FPS 14,370 2,760 I FPS FPS 14,250 FPS SECTION SW-14 Ek SL80-9 R 2000 1800 1 4600 .'.pj 1400 1200 TEST PIT TP-E15 SAMPLE I -WEIGHING a SPLITTING WATANA BORROW SITE E SECTIONS 2000 1000 1600 1400 1200 TYPICAL STREAM -WASHED GRAVEL SUSITNA FLOODPLAIN, WESTERN SITE E LEGEND CONTACTS) --- --- APPROXIMATE TOP OF ROCK GEOPHYSICAL SURVEYS TSW-10 SEISMIC REFRACTION SURVEY END OR TURNING PONT SW-10 1978, SHANNON R WILSON SL 80-9 1980, WOODWARD-CLYDE CONSULTANTS ••••••••••• SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND FPS NOTES 1. SECTION LOCATIONS SHOWN ON FIGURE 6.43 2. ALL SECTIONS LOOKING UPSTREAM (EAST). 3. VERTICAL AND HORIZONTAL SCALES EQUAL, 4, SECTION ELEVATIONS FROM REFERENCED BASE MAPS, TRACED AT 25' CONTOUR INTERVALS. 5, ADDITIONAL PHOTOS AND SKETCHES OF TYPICAL BORROW SITE CONDITIONS SHOWN ON FIGURE 6.53 6, ZONES INDICATE MATERIAL TYPES AS DESCRIBED IN TEXT. INFERRED ORIGINS ARE, I, SUS17NA RIVER ALLUVIAL GRAVELS II. TSUSENA CREEK BED ALLUVIAL GRAVELS 1W, OUTWASH OR HIGH LEVEL HISTORIC GRAVEL H SAND TERRACES 7. SECTIONS LIE ON SHANNON 8k WILSON 1978 SEISMIC LINES, COE 1978, AND S R W 1978. B, REFER TO TABLE 6,1 FOR SEISMIC VELOCITY AND MATERIAL CORRELATION. 9. PHOTOS TAKEN APRIL, AUGUST 1981. 0 200 400 FEET SCALE FIGURE 6.44 ACES I P 44619AR Aq JOSIDOO WDOAd 0 Q R 0 8 IS%II WARM of I LU z 0 J 3 6 U cn Z 0 u- w O Q uT w ~ a a E z Cl) _ a c7 w 9000 �LL, oLr) "v a UN IJ� n 0 J �+ w Q 0 6 O to U •• n w 8 J - a J m 0 w m 8 � z � 0 J O F- S m O oC r� to L6J Ir C7 LL J46!a M Rq aaui: JuaaJ2 d ga• C A4810tA Aq J921007 lua:)Jad R ■■■■■■■■■■■■■■■■■■■■ . �i�iiiiiiii��■iiiiiiii iiiiiiiiiiiiiJ•/%/I/%��►/'�'�I� slimming■� solve oil • mmmm ww!!Aumm//%//.ammmm - ��iiiii��i�i�►�s��r►r►�Irr�■r�ii III',,//��'/. �j� I 11111011018111 Nogin J SII.i%AVAWAWAV",II/mw'j IIWAWAiiiiiiii 7/ WAN %AID/II",dFA*wwi%II/.A•���� 01,10A P a mol■■i■�■■ I�r�� samm.omam//.■■S■E■M m■ f%mammam W■■MENE■M■ �mmomm � .�" �--m-- ---- Ilm II./LUJmm/l/m iii Jiilrtmimmmmmmmmm 11111111 son i■■■■■■■■■IMEM■■■■■■■ ---- mmmmmummmmmmmmm ==IMIMIN iiii iiiiiiiiiiiiiiiiiiii - iiiiiiiiiii��i�iiiii. iw��ww�r1r11i���iiiiiiiiiirr� o LL z a E f 8 �L w Q N p 0 O (.? N W L c in c W Q J N m U- 0 X W N W z 0 � a 0 «i LL d3 0 U Q N o z H � F— N 0 0 LJJ III (D 0 Z li 14BIOM Aq JauI_A4ua0rad tD 0 Ci LEGEND ul w CONTACTS: N �3p �io_o_ _MATERIAL LIMIT BOREHOLES AND TEST PITS: 0AH-HI 1981,AA) AUGER BORING (D SAMPLE LOCATION (APPROXIMATE) AH-Hi —0-111 - 277 �_S BORROW SITE H NOTES r I. AH-H CONTOUR INTERVAL 100',TRACED FROM ENLARGED REFERENCED BASE MAP. Z.MATERIAL LIMITS BASED ON FIELD AND AIR PHOTO INTERPRETATION, FINAL MAPPED LIMITS OF BORROW SITE AH-116 SUBJECT TO RESULTS OF DESIGN INVESTIGATIONS, N3.205 00G AH-H3 3. BORROW MATERIAL IS GLACIAL OUTWASH AND AH- TILL OVERLYING BEDROCK. DEPTH TO BEDROCK ESTIMATED TO AVERAGE 40 - 50 FEET. OAH-H4 4. ENTIRE BORROW SITE LIES OUTSIDE OF PROPOSED WATANA 4 AND DEVIL CANYON RESERVOIR LIMITS. S. EXPLORATION LOGS SHOWN IN APPENDIX F. Ali-H2 6, PHOT09 TAKEN AUGUST 190t (LEFT), SEPT. 1980 (RIGHT}. h" _4 111' 'q " NAt? �1000q1., 00 BORROW SITE H REFERENCES:BASE MAP FROM R aM,1980-1"=2000' RESERVOIR COORDINATES IN FEET, ALASKA STATE PLANE (ZONE 4) TYPICAL BORROW MATERIAL EXPOSURE WATANA BORROW SITE H PLAN 0 [OOD 2000 FEET SCALE FIGURE 6.48 114619M Aq leOsaoo� p�ua��ado p O O 2 2 tp F m Bi 8 a � N o O U l!i CO W o � (n LL w v_ o 0 in 0 :� 08 m mmmmmmimmimmimmmim Bid o g a o� Q a Q o u' uJ Q ~ r Q ® v J 3acz ® < U) w E p LL z' U p Q O F- v v c v g Q U] J J W W d' > Q U J Now a in W ~ J o Q 3 3 W 8 "z LLJ U) ' vai o � u z m cn cn o H z a m U y (n DI n � vNis w .0 ON g $ o 0 0 tgb�a* dq jauij 4ua-)racj ■■■■■■■■■■■■■■■■■■■■ ■■■■■■■■■■■■■■■■■■■■ ■■■■■■■■■■■■■■■■■■■■ �r o, I k BORROW SITE H SEE FIGURE 6,48 i - i j f / ,t P.-,_. ,l : !'• � Tip-R 1, f } _ Ms 2D5,Cif30 P[ 3,,2,14,Dt7p i ') ? N 3,219,000 TP-RE. OQ I nG f A TP-R19 i x. + - ' /v c REFERENCE: BASE MAP FROM R &M,1981-1"=2000' RESERVOIR MAPPING, COORDINATES IN FEET, ALASKA STATE PLANE ( ZONE 4 ). WATANA BORROW SITE I PLAN L7 I O L.# I TP-R22 .r I BOREHOLES AND TEST PITS: tFOTP-R61981,AA4 TEST PITS AND TRENCHES GEOPHYSICAL SURVEYS: ASLBI-B SEISMIC REFRACTION SURVEY END OR TURNING POINT- 1981, WOODWARD-CLYDE CONSULTANTS NOTES I. BORROW SITE PHOTO SHOWN ON FIGURE 6.53. 2.CONTOUR INTERVAL 100' TRACED FROM I"-1000` ENLARGEMENT OF REFERENCED BASE MAP. 3. BORROW MATERIAL IDENTIFIED IS RIVER GRAVEL AND SAND DEPOSITS, INCLUDING ACTIVE FLOOOPLAIN,MID- RIVER BARS, AND TERRACES NEAR RIVER LEVEL, 4.MATERIAL LIMITS BASED ON FIELD AND AIR PHOTO INTERPRETATION, FINAL MAPPED LIMITS OF BORROW SITE SUBJECT TO RESULTS OF DESIGN INVESTIGATIONS. 5. ENTIRE BORROW SITE AS DRAWN LIES WITHIN PROPOSED DEVIL CANYON RESERVOIR LIMITS. LOCAL DEPOSITS ARE INFERRED TO CONTINUE UP SLOPE BEYOND LIMITS SHOWN. 6. EXPLORATION LOGS AND SEISMIC LINE DATA ARE SHOWN IN APPENDIXES F AND I. T EASTERN LIMIT OF SITE COINCIDES WITH DOWNSTREAM LIMIT DF BORROW SITE E AND MATERIALS ARE CONTINUOUS BETWEEN SITES, 8. TEST PIT LOCATIONS APPROXIMATE - 9. TEST PITS R-12 THRU 14 SHOWN ON FIGURE 6,43( AREA E �. 0 1000 2000 FEET SCALE FIGURE 8.5E f I I, f zffL � f CCp t\ „��1 -..,% � ".�i •- - _ �\�, ;�.i,' /•r � p0 . i try \ � 1, � �' 1 SUSITNA <_J .� -�: RIVER 1 F _ - v- ��--'" y W 0 � Ii � � 1 _ J 20 APPROXIMATE DAM CENTFRi_INF: 1- f J 'fi y / PR7S/ - st 1 SUSITNA RIVER_ - =I Jt "C i700_..' Sl BI3 TPRB F r`{ i r Ji 0 N J/ - R- I `r N(FlGURE \ REFERENCE: BASE MAP FROM R dM,1960-I"=2000' RESERVOIR MAPPING, COORDINATES IN FEET, ALASNA STATE PLANE (ZONE 4) LEGEND CONTACTS; MATERIAL LIMITS BOREHOLES AND TEST PITS: Ul TPN-i 1981, AAI TEST PITS AND TRENCHES GEOPHYSICAL SURVEYS: n SL.E1i-I SEISMIC REFRACTION SURVEY END OR TURN€NG POINT-1981, WOOOWARD-CLYOE CONSULTANTS NOTES I. SITE PHOTOS WITH SECTION SHOWN ON FIGURE 6,53. 2.CON TOUR INTERVAL 100, TRACEb FROM I •1000 ENLARGEMENT OF REFERENCED BASE MAP. 3, BORROW MATERIAL IDENTIFIED AS RIVER GRAVEL AND SANDS, MID -RIVER BARS,AND LIMITED TERRANCES NEAR RIVER LEVEL, 4. MATERIAL LIMITS BASED ON FIELD AND AIR PHOTO INTERPRETATION. FINAL MAPPED LIMITS OF BORROW SITE, SUBJECT TO RESULTS OF FINAL DESIGN INVESTIGATIONS, 5, ENTIRE BORROW SiITF LIES WITHIN PROPOSED RESERVOIR LIMITS. 6- EXPLORATION LOGS AND SEISMIC LINE DATA ARE SHOWN IN APPENDICES F AND L 7. BORROW SITE COULD EXTENDUP TO E820,000 WITH TOPOGRAPHY AND RIVER CHANNEL CONDITIONS SIMILAR TO THOSE SHOWN BETWEEN E785,000 AND E 790,000. B. TEST PIT LOCATIONS APPROXIMATE. - --- _ 0 1000 2000 FEET SCALE i 1 WATANA BORROW SITE J PLAN FIGURE 6.52 €.' a r 14110 a � 1300 w 1200 tsuKKuw SI I It 1 (DOWNSTREAM OF WATANA) uuI HI F�UJCENH U fCLM UN --lu -Imm an Iu WATANA-RIVER ALLUVIUM TYPICAL SECTION LEGEND LITHOLOGY: SANDS, GRAVELS ABOVE WATER TABLE. 'qo POSSIBLE COARSER RIVER ALLUVIUM ASSUMED TO BE TILL, PENDING RESULTS OF DESIGN INVESTIGATIONS. IIMM -% BEDROCK(DIORITE d/OR ANDESITE FLOWS) CONTACTS: --- BORROW LIMITS ---- ASSUMED TOP OF ROCK GEOPHYSICAL SURVEYS: ......•••• SEISMIC VELOCITY CHANGE FPS SEISMIC VELOCITY IN FEET PER SECOND FPS NOTES I. PHOTO LOCATIONS B BORROW SITE MAPS SHOWN ON FIGURE 6.43 (SITE E), FIGURE 6.51 (SITE I), FIGURE 6.52 (SITE J), AND FIGURE 6.53. 2. PHOTOS TAKEN AUGUST 1981. 3. REFERTO TABLE 6.1 FOR SEISMIC VELOCITY AND MATERIAL CORRELATION. 0 200 400 FEET 4. VERTICAL SCALE 2TIMES HORIZONTAL, SCALE BORROW SITE J BORROW SITES Ili J UPSTREAM OF WATANA) TYPICAL RIVER DEPOSIT (PHOTO TAKEN IN BORROW SITE E UPSTREAM OF SITE I NOTED ON TYPICAL SECTION) WATANA BORROW SITES Ej a +J R MUMS R TYPICAL SECTION FIGURE 6.53 ��"�� ■■■■■■■■■■■■!�■fi�rr �11� . • .��l�!!l��� �L�l�F���� J� is wool _E11NO1N11E11111� 1sm 1m112 • ArnamommmammmmE1NW/S■e■■■ a■®ammamm ; Mfm'� OMM MMMMMUMNAWWOM■ �ae�ri��w■��Mar��ww��e�sa��rser�a� ram f ��.■�►®■tea■■■�i�a®�®�..■� . hC�!lIEBlW�7��71�i1�'Si�JI�J�fr��/ll��� ►#N 9MMMi Wh AI�I I��i� �i i • v RA ■I��l�■■■■■ on _ FAWMASO • ■ a■■■■ son loss■ :■■■ lME OEM E ollimmmm MoMEM ll■S_■■_mm mmmm loomom 1700 1650 w 1600 w SUSITNA �`. RIVER z - 15BO Q W W 1500 E L.1473.0 1450 O'er-- AZIMUTH OF SECTIONLIMIT OF / / I / EL.1480,0 (ASSUMEDN) ------------------------------------L-_-_----------_------------- SECTION B-B 1700 1650 H 1600 SUSITNA _2 1550 TRIVERU- wJW1500 1450 1850 1800 1750 1700 F- w w 1650 z 0 E- j 1600 Ld W 1550 1500 1' $4150 " Ong_ AZIMUTH ,180' f)F .SFf".TION I 0.. AZIMUTH , 180° OF SECTION SECTION F-F LIMIT OF EXCAVATION —EL.14B0.0 (ASSUMED) ------L--------- --------------------- SECTION D-D --1 1700 1650 1600 1550 1500 1450 1700 1650 1600 1550 1500 1450 QUARRY SITE L. PHOTO — / 0 %00 0 w .— ---�W \100 D — N 3 22B 30 18 - i700` J_ 00 — 1470 — B 0 200 N 3 228 50 _ 400 FEET - SUSITNA RIVER D FLOC v SCALE PLAN WATA N A QUARRY SITE L PLAN AND SECTIONS LEGEND CONTACTS: ----- LIMITS OF USABLE ROCK (ASSUMED) ---- MATERIAL LIMITS ---- APPROXIMATE TOP OF ROCK — ASSUMED TOP OF SOUND ROCK B B CROSS-SECTION LOCATION NOTES 1. SECTION LOCATIONS SHOWN ON PLAN INSERT, 2.ALL SECTIONS LOOKING UPSTREAM (EAST). 3. VERTICAL AND HORIZONTAL SCALE EQUAL. 4. SURFACE ELEVATIONS FROM I''200' TOPOGRAPHY — COE,1978,TRACED AT 25' CONTOUR INTERVAL, 5. ZONES INDICATE LEVEL OF CONFIDENCE IN ROCK AVAILABILITY AND QUALITY FOR QUARRY USE. ZONE II MAPPED AS DIORITE PORPHYRY, COMPETENT AND BLOCKY. ZONE I INFERRED AVAILABILITYON BASIS OF OUTCROP EXTENT AND GENERAL SITE GEOLOGY, 6. DEPTH TO ROCK AND WEATHERED ROCK THICKNESS EXTRAPOLATED FROM AIR PHOTO INTERPRETATION AND GENERAL SITE GEOLOGY. 7. MATERIAL LIMITS INFERRED FROM PRELIMINARY MAPPING AND ARE SUBJECT TO REFINEMENT AND VERIFICATION IN DESIGN LEVEL INVESTIGATION. B. ENTIRE QUARRY SITE LIES WITHIN PROPOSED RESERVOIR LIMITS. 9. ROCK IS INFERRED TO EXTEND TO SOUTH OF AREA LIMITS, BUT QUANTITY AND OVERBURDEN DEPTHS ARE UNKNOWN. 10, LOCATION OF SEISMIC LINES ADJACENT TO QUARRY SITE SHOWN ON FIGURE 5.Ib. 0 50 100 FEET SCALE FIGURE 6.5.6 A��E REFERENCE: BASE MAP FROM COE,1978 I"=200' WATANA TOPOGRAPHY, SHEETS 8 a 9 OF 26 COORDINATES IN FEET, ALASKA STATE PLANE {ZONE 4) 7 - RESULTS OF GEOTECHNICAL INVESTIGATION - DEVIL CANYON 7.1 - Devil Canyon Damsite This section discusses the results of a geological and geotechnical in- vestigation performed at the Devil Canyon site. This section is pre- sented in two subsections: 7.1 - Devil Canyon Damsite and 7.2 - Borrow and Quarry Sources and Materials. Location of maps presented in this section are shown on Index Map Figure 7.1. (a) Overburden Conditions (i) General The proposed Devil Canyon damsite occupies a narrow deep gorge on the 5usitna River approximately 26 miles down- stream from the Watana site at river mile 152 (Figure 4.1). The terrain is one of a glacially scoured mountain area with many deeply incised tributaries cutting down through the steep canyon walls to river level. The overburden within the region generally consists of less than one foot of organics over a veneer of glacial outwash and reworked tills, mixed with talus on the steeper slopes. Glacially scoured bedrock knobs and ridges form a fairly pronounced topography with a grain paralleling the river. A map show- ing the inferred top -of -bedrock elevations and existing surface topography is shown in Figure 7.2. Geologic profiles at the damsite and borrow sites is pre- sented in Section 7.1 (b). Much of the interpretation used in preparation of these maps and figures have been based on seismic velocities of various soil and rock types. Results of the seismic refraction surveys performed for this study are presented in Appendices H and I, while surveys per- formed in previous studies are contained in referenced reports (12,39,57, and 59). For clarity, Table 7.1 pro- vides a correlation of seismic velocities with soil and rock types that have been used in this study. (ii) Damsite The bedrock at Devil Canyon is well exposed along the can- yon walls from the entrance of the gorge immediately up- stream from the proposed damsite to Portage Creek down- stream. On the upper abutments, overburden consists pri- marily of weathered rock and talus mixed with shallow out - wash and reworked tills averaging approximately 10 feet thick (28). -1ACRES On the 50' to 90' slopes in the gorge, overburden ranges from zero up to perhaps 30 feet thick. Overburden in these areas consist of scattered debris on rock ledges and talus slopes. These talus slopes, which extend into the river, are generally confined to gullies within the gorge wails. Although the high river flows (up to 35 fps) prohibited sampling, it is assumed that the channel alluvium consists of unstratified talus blocks and boulders mixed within a matrix of smaller rock fragments, gravels, and sand. Total depth -to -bedrock in the channel beneath the proposed dam - site and cofferdams is estimated to be approximately 60 feet, of which 20 to 30 feet is water and 30 feet river alluvium. The maximum depth of river alluvium was calcu- lated based on USBR drill holes DH-12, DH-13, DH-14, and the 1981 Borehole 5a, which crossed beneath the river (Table 5.2). Portal structures for diversion tunnels and intakes will be placed in areas of shallow overburden. Upstream from the damsite, beneath Borrow Site G, bedrock appears to drop-off sharply with overburden reaching depths up to 300 feet. This area is discussed in a subsequent section. (iii) Surface Structure Sites Proposed surface structures on the north abutment are ex- pected to encounter the same general soil conditions as at the damsite, with overburden averaging about 10 feet or less, and comprising mostly talus with isolated outwash materials. Any structures on the south abutment would en- counter similar conditions as those which exist at the saddle damsite (Section 7.lEa]Ev]). (iv) Emergency SpillwM The proposed emergency spillway lies to the south of the damsite on an east -west trending ridge of exposed partially covered bedrock (Figure 7.2). In general, overburden is expected to be less than 10 feet thick along the proposed east -west spillway alignment. However, where the proposed spillway turns northward (approximately 2,000 feet downstream from the dam center- line) the structure will cross a relict channel, which contains up to 80 feet of alluvium (Section 7.1Ea][v]). lacAis]7-2 (v) Saddle Dam The overburden at the surface in the proposed saddle dam and emergency spillway area (Figure 7.2) consists primarily of reworked glacial till. The areas of steep topography have isolated talus deposits and include a number of shal- low (<10 feet) weathered bedrock zones. Beneath the lakes, where the proposed saddle dam is sited, bedrock drops off into a deep, overburden -filled trough (Figure 7.2). Based on seismic and borehole data, the stratigraphy in the channel appears to comprise approxi- mately 10 to 20 feet of outwash (sandy, bouldery till), underlain in the deeper sections by stratified layers of sand and gravel. This underlying material appears more compact and clean than the overlying surficial deposit (51). Maximum overburden depth in the channel area, as determined by borings and seismic refraction lines (Figure 5.2), is 86 feet, with an average of about 40 feet at the saddle dam - site. It is postulated that this deep bedrock trough rep- resents a relict channel of the Susitna River (Appendix J). Drilling in this channel shows the material to be dense and relatively impervious. The existence of several lakes on top of this channel (perched at about 75 feet above rock level) demonstrates the overall impermeable nature of this material. (vi) Camp Areas Although detailed investigations were not conducted at the proposed campsite area located approximately 7,000 feet downstream from the dam, reconnaissance mapping suggests that bedrock is near surface. Where bedrock is not ex- posed, overburden is expected to be an average of 5 to 10 feet thick, consisting of sandy, bouldery outwash with localized zones up to 40 feet deep. The only areas around the damsite expected to have very deep overburden are: (a) the upper reaches of creeks from Elevation 1500 to 1800, (b) areas of pond water, and (c) the relict channel (Figure 7.2). Localized clean sand and gravel deposits will pro- bably be scarce throughout the area. (b) Lithology (i) Introduction The bedrock in the Devil Canyon damsite is exposed along the canyon walls of Cheechako Creek and the Susitna River and in scattered outcrops throughout the area (Figure 7.3). 7-3 RCBfS' f Bedrock at the site is a Cretaceous age (Table 4.1) se- quence of interbedded argillite and graywacke which lies on the western side of a Tertiary age granodiorite pluton. The argillite and graywacke have been intruded by felsic , and mafic dikes of uncertain age, These rocks have not been assigned formational names, but rather have been given lithologic names for mapping and correlation purposes. Rock names are based on the classification of Travis (43). The lithology and structure of the Devil Canyon site are shown on a geologic map (Figure 7,3) and geologic sections DC-1 through DC-7 (Figures 7,4 through 7.10). The geologic interpretations are based on field mapping, borehole and seismic refraction data (Section 5). The locations of the proposed civil structures are shown on the geologic map and sections. Rock exposures in Devil Canyon are nearly continuous along the canyon walls; however, above the break in slope at about Elevation 1400, rock exposures are more limited. Access in this area is very difficult due because of steep slopes. Because of this lack of exposures, the extent of geologic features could not be determined. Future subsur- face explorations will be required to verify areas of in- ferred geology. In general, only structures more than 1 foot wide are shown on the map unless otherwise noted. Geologic features mapped at the surface were correlated, where possible, to similar features in the boreholes and on seismic profiles. These features are shown on the geologic sections (Figures 7.4 through 7.10). Areas of insufficient subsurface data required extrapolation of geologic features to depth based on mapped surface orientations. For simpli- city, borehole data are limited to features 5 feet or greater in thickness. For more detailed information, see Appendices C and E for borehole logs and pressure testing details, and Appendices H and I for seismic refraction sur- veys. The geologic sections have been oriented to make best use of the available geologic data. Approximately 1,200 joints were mapped at the site. This information was used in developing the statistical joint plots shown in Figure 7.13. On the geologic map ( Figure 7.3) only representative joints from the two major joint sets are shown. Details of the lithology and structure at the Devil Canyon site are presented in the following sections. f acA�l 7.4 Granodiorite The granodiorite is located primarily to the east and south of the site ( Figure 4.1) . The closest occurrence in the damsite area is approximately 3,500 feet to the southeast, where the contact with the argillite and graywacke is ex- posed in Cheechako Creek. The contact zone extends over an area up to about 100 feet wide which contains large argil- lite and graywacke blocks intruded by the granodiorite. Contacts are generally sharp with thin fracture zones on either side. The granodiorite is light gray and fine to medium grained. It contains quartz, biotite, plagioclase and orthoclase feldspars. Where exposed, the rock is fresh and hard to very hard and massive. The granodiorite has been intruded by both mafic and felsic dikes. The extent and depth of the pluton beneath the site is not certain nor is the dip of the contact known. In BH-2, a quartz diorite and granodiorite intrusive were intersected from Elevation 663.0 to the end of the borehole at Eleva- tion 645.7 (Figure 7.5). The fine grained groundmass and coarser phenocrysts of this granodiorite are similar to a diorite dike intersected in BH-7. It is uncertain whether the material intersected in BH-2 is a dike or part of the main pluton. (iii) Argillite and Graywacke The rock underlying the Devil Canyon site is a slightly metamorphosed sequence of interbedded argillite and gray- wacke. The argillite is a medium to dark gray, very fine to fine grained argillaceous rock. The argillite is very thinly bedded, hard and generally fresh. Petrographic analyses show that the argillite is composed of subrounded to elongate grains of primarily quartz and biotite with minor iron oxides, pyrite, organic material, amphiboles, and carbonate (53). Some euhedral biotite flakes up to 0.12 mm were observed. Elongated grains are parallel to the bedding. The graywacke is light to medium gray occasionally varying to a dark reddish gray. The rock consists of fine to medi- um grained sand -sized grains in a very fine grained argill- aceous matrix. Beds are often graded. Zones of coarse grained lithic conglomerate are found locally. Where map- ped, these zones are less than 100 feet thick. However, in BH-1, coarse grained material was encountered between bore- hole depths 331 to 750 feet (Appendix C). Since this hole was drilled at an angle to bedding, the apparent thickness ,.5 RCflIS is greater than the true thickness of the unit. Petro- graphic analyses Show the graywacke is similar to the argillite and composed of quartz, feldspar, and biotite with minor iron oxides, pyrite and organic material. Pyrite and other sulphides are generally less than 1 per- cent, but locally range up to 5 percent of the rock mass in both the argillite and graywacke. The argillite and graywacke interbeds range from less than 1 inch to greater than 10 feet thick, but are generally less than 6 inches. Figure 7.11 is a photograph of the typical interbedded argillite and graywacke found at the site. Contacts between the beds are sharp and tight with bedding parallel to foliation. The generally weak folia- tion is better developed in the argillite than the gray- Wacke because of the effect of grain size. Foliation, as described here, refers to the planar structure of the rock resulting from the parallel alignment of platy and elongate grains. In most boreholes and in some outcrops, the folia- tion has developed a phyllitic sheen in the argillite beds. Bedding/foliation strikes northeast with dips to the south- east of generally 50' to 70°. The dip of the bedding/foli- ation is shown on the geologic map and sections. 0n the geologic sections, the apparent dip is indicated where appropriate. A minor secondary foliation was found subparallel to the main foliation. The argillite and graywacke have been injected with numer- ous quartz veins and stringers. Stringers are defined as quartz injections less than 0.5 inches thick. Veins are quartz injections greater than 0.5 inches thick, while veins are greater than 1 foot wide. At least two episodes of injection have been observed. The first episode con- sists of quartz veins and stringers parallel and subpar- allel to the bedding/foliation. These veins and stringers, which may have been injected before or during deformation, have been stretched, folded, and occasionally offset along foliation planes. The contacts of the veins and stringers with the bedrock are tight and very hard. The veins and stringers occur either singly or in groups measuring up to 10 feet wide in outcrops and up to 30 feet along the bore - holes, In these zones, the amount of quartz is as much as 20 to 40 percent of the whole rock. In general, however, these zones are less than 1 foot wide. These veins and stringers are good quality rock with high RQDs. The second episode of quartz intrusion is represented by undeformed, post -deformational quartz veins which cut across the bedding/foliation and the quartz intrusions of the first episode. These veins also contain iron and lead sulphide mineralization. These quartz veins are associated with very closely to closely fractured rock. RQDs are us- ually slightly lower in these zones than the surrounding rock. Most of the veins are less than 2 feet wide. Although quartz encountered in boreholes BH-1, associated with in both felsic (iv) Dikes veins and stringers of both episodes are all boreholes, they are most numerous in BH-2 and BH-4. Quartz the second episode of and mafic dikes. veins and stringers intrusion are found The argillite and graywacke at Devil Canyon have been in- truded by a series of mafic and felsic dikes (Figures 7.3, 7.4, 7.5, and 7.10). The mafic dikes are designated M 1 through M 4, while felsic dikes are designated F 1 through F 8. Geologic technical climbers were used to map the location and extent of these features along the canyon walls from the mouth of the canyon downstream to about the locations of DH-12 and DH-14 (Figure 7.3). The dikes gen- erally occur in topographic lows or gullies. Some of these gullies had been misinterpreted by previous investigations to be shear zones. A survey control of the locations of four dikes (M 1, M 2, M 3, and F 4) in the damsite area was performed for the purpose of insuring an adequate correla- tion across the Susitna River. A magnetometer survey, per- formed on the south bank, was unsuccessful in tracing their extent beneath the overburden away from the gorge walls. Four mafic dikes were mapped in the damsite area. Dikes M 1, M 2 and M 3, are in the area of the powerhouse and the diversion tunnels, while M 4 is located approximately 2,000 feet downstream from the dam centerline (Figure 7.3). Strikes of the mafic dikes are approximately northwest - southeast, crosscutting the bedding/foliation and trending parallel to Joint Set I (Section 7,1[c]). Dips are verti- cal to steep to the northeast and southwest. The mafic dikes are generally dark green to dark gray, fine grained, fresh to slightly weathered, and hard. They consist pri- marily of feldspar in a fibrous groundmass with accessory pyroxene, biotite, hornblende, and calcite. In BH-1 and BH-2 mafic dikes contain from 5 to 10 percent euhedral, white, radiating zeolites up to 0.2 inches in diameter. The mafic dikes have been classified as diabase. Joint spacing in the dikes is very close to close with -, ACAS slickensides and chlorite on most surfaces. Because of the joint spacing, the dikes tend to erode more readily than the surrounding argillite and graywacke resulting in their forming talus -filled gullies. Dike widths vary within the same dike ranging from 2 to 10 feet. The borders of these dikes are generally finer grained with "chill zones" usually 0.5 to 1 foot wide. Contact metamor- phism is evident in the argillite and graywacke adjacent to the dike. Fractured and shear zones ranging from 1 to 10 feet but generally less than 5 feet wide, are frequently found immediately adjacent to the contact. The felsic dikes are light yellowish -gray to gray and aphanitic to medium grained, but generally fine grained. They range from rhyolite to granodiorite in composition and contain quartz phenocrysts. The felsic dikes are generally iron oxide stained and, at the surface, are slightly to moderately weathered. At depth, they are fresh and hard. Because of the very close to closely spaced joints, the felsic dikes tend to erode readily and form talus -filled gullies. Figure 7.12 is an aerial view of the site showing the gullies in which the dikes occur. The contacts are healed, but with secondary localized shearing or fracturing at or near the contact. Chilled margins up to 3 feet wide are evident in the larger dikes, with contact metamorphism in the argillite and graywacke. The orientation of the majority of felsic dikes is predom- inantly northwest and north, with vertical to steep dips to the east and west. These dikes are generally parallel to Joint Set I (Section 7.1[c]) and cut across the bedding/ foliation. Several small felsic dikes, however, were noted in the borings to be parallel to the bedding/foliation. The width of the felsic dikes varies from 2 to 60 feet, but in the immediate site area is less than 10 feet. The wid- est dikes are found upstream from BH-5a and from approxi- mately 2,500 feet downstream from the dam centerline (Figure 7.3). The widest felsic dike at the site is ex- posed on the north bank of the river north of Borrow Site G (Figure 7.3). This dike is up to 60 feet wide but pinches out to less than 10 feet at either end of the outcrop. The trend is northwestward with a 75' dip to the northeast. The dike is light gray but weathers to a yellow -orange caused by iron oxide staining. Grain size is fine with fine to medium grained quartz phenocrysts. RCNE3� 7a (c) Structure (i) Introduction This Section discusses geologic struct4re5 at the Revil Canyon site and their relation to the proposed dam location and tunnel routes: The section is divided into two subset- tions. The first discusses joints and joint sets while the second discusses shear and fracture zones 0 i ) joints The orientation of major and minor joint sets was recorded At all outcrops, as well as the condition of the joint sur- faces, spacing, and any Mineralization or coatings Four joint stations (pCj-1 through DCj-4) were also seloctod for detailed joint measurements (Figure 7,13) in areas consid- ered to be representative of all -joint sets. One hundred joints were recorded at each of the stations except DCJ-I where 93 joints were recorded. For each sto- tion, joint measurements were plotted on the lower hemis- phero of a Schmidt equal-area stereonet at 1, 3, 6, 71 10, and 15 percent contours (Figure 703), The plotting method is described in Figure 6,12, In addition to the joint station plots, composite joint plots were constructed from joint stations and outcrop data, Composite plots were constructed for the north and south banks and are shown on Figure 7,13. Four joint sets were mapped at the Devil Canyon site and are identified on both composite and joint station plots, Sets I and II are major sets which occur throughout the site area, while Sets III and 1V are less prominent but are locally strong* Table 7,2 is a summary of joint set orlon„ tations, dips, spacings, surface conditions, and structural relations, Faeh ioint set is discussed below, This discussion is based primarily on surfaco jointing; as it was not possible to correlate between joint in outcrop and those encountered at depth in the borehole, Jointing in boreholes is discussed in a later section] joint Set I is the most prominent set at the site, The trend is northwest (3401 with vertical to stoop dips to the northeast and southwest, Oo the south bank, the aver- age dip is vertical, while on the north bank, the 4vora9e dip is 841 t4 the northeast, Ooint spacings vary from 0,5 inch in fractgre zones up to 10 foot, with an average spae- ing from 1,5 foot to F feet. These joints are planar and smooth with occasional iron oxide staining and carbonate coating. Set I joints are very continuous and range from tight to open. Open joints are well developed on the south bank and can be traced horizontally for over 150 feet. These joints are open up to 8 inches at the surface. Set I joints are parallel to most of the shears, fracture zones, and dikes in the site area. A subsidiary joint set, Ib, to Set I was found locally at DCJ-4 and possibly at DCJ-1 (Figure 7.13). This set strikes northwest (320°) and dips 55° to the northeast. Joint Set II includes joints parallel and subparallel to the bedding/foliation planes. This set strikes generally northeastward but ranges from 020' to 100°. The average trends on the north and south banks are 065' and 075°, res- pectively. Dips are southeast, averaging 55' on both banks. Joint spacings are generally 1 to 2 feet. The joint surface conditions are variable, from planar to curved and sinooth to rough, as a result of folds and cren- ulations on the bedding/folation planes. No mineralization was found on joint surfaces at outcrops; however, in the boreholes, these joints are often coated with chlorite. Set II joints are generally tight but tend to be open on the north bank near river level owing to stress relief. Slopes on the north bank are parallel or subparallel to Set II. In the damsite area, the course of the Susitna River at the damsite parallels this joint set. Major and minor shears are associated with Set II joints and are discussed in the following section (Shears and Fracture Zones). A subsidiary joint set, IIb, was mapped at DCJ-1 and DCJ-4. This subset trends north-northeast at 015' with steep (75' to 85°) dips to the southeast. Joint Set III is a minor set, although locally well devel- oped. A similar set was described by the USBR (51) in the vicinity of DCJ-3 on the south bank (Figure 7.13). Set III is northeast trending with moderate to steep dips to the northwest. On the north bank, the average strike and dip are 060' and 80' to the northwest, while on the south bank, the strike and dip average 025' and 65' northwest. The Set III joints are planar to irregular and smooth to rough, with spacings generally 3 feet. Occasional traces of iron oxide and carbonate are found on the joint surfaces. Both open and closed joints have been found in Set III. Open joints are most common on the north bank, particularly above Elevation 1400 near DCJ-3, where cliffs have formed parallel to Set III. The continuity of Set III joints could not be determined. RCRES 710 Block failures and slumping on the south abutment appear to be associated with Joint Set III. A large block was mapped between DH-1 and DH-10 on the south side on a 10-foot deep northeast trending depression. Other loose blocks related to this set have been observed to extend at least 25 feet below the canyon rim. Attempts by the USBR to excavate rock benches into the abutment to determine the extent of slumping were inconclusive. However, it is likely to assume that detached blocks may extend up to 50 feet back from the gorge walls. Joint Set IV consists of numerous low angle (dipping less than 40°) joints. The strongest trend of Set IV joints is northeast and east, with low angle dips to both the north and south. The southerly dips are best developed on the north bank at DCJ-3. A strong northerly dip is evident at DCJ-1 on the south bank and DCJ-2 and DCJ-4 on the north bank (Figure 7.13). DCJ-2 shows both dip directions; how- ever, the northerly dip is the strongest. A secondary low angle set trends northwestward with dips to the northeast. This set is best developed at DCJ-1 and DCJ-2. Locally, the canyon slopes are failing along joint planes and sliding or slumping towards the river. On the north bank, most movement is along the Set II (bedding/foliation) joints which parallel and dip toward the river. Slopes are generally subparallel to these joints, with slopes general- ly at 40' to 50' (Figures 7.6 and 7.8). On the south bank, slopes are steeper (60' to 80°) and are controlled by the intersection of Sets I, III and IV. Areas of open joints that could affect engineering design were identified at the Devil Canyon site. Open joints of Set I were mapped at several areas on the south bank par- ticularly east of Borehole DH-1 where four open joints were traced southeastward up to 150 feet from the edge of the canyon (Figure 7.3). These joints are up to 6 inches wide with undetermined depth. Borehole BH-3 (Figure 7.3) was drilled northeastward toward the cliff face to intersect open joints at depth. Zones up to 10 feet wide of open and jointed rock were encountered along the length of the bore- hole to a vertical depth of over 100 feet (approximate Ele- vation 1300). Drill water was lost at a depth of 122.4 feet along the hole and never regained. RQDs for BH-3 were low, particu- larly near the bottom of the hole as it neared the cliff face (Figure 7.6). Open joints were also encountered in USBR Boreholes DH-1, DH--8, and DH-9 which were drilled sub - parallel and across Set I. High water losses and low RQDs were also encountered in these holes which reflected this open jointing. -11 RCRES - Shears and Fracture Zones This section discusses the shear and fracture zones mapped at the Devil Canyon site. These features are shown on the geologic map and geologic sections (Figures 7.4 through 7.10). - Shears Shears are structures having breccia, gouge and/or slick- ensides indicating relative movement. Both healed and unhealed shears were found at the site. Healed shears consist of an argillite and/or graywacke breccia within a quartz matrix. These zones may represent syndepositional deformation that has subsequently been lithified and healed into a hard competent rock. These zones, there- fore, do not represent a structural weakness or discon- tinuity in the rock mass. These features were most evi- dent in Boreholes BH-1, BH-2, and BH-4. The largest healed shear was found in BH-4 (Figure 7.6) from 221.0 to 252.0 feet. This zone consists of argillite breccia in a zone of highly folded and stretched quartz veins which were intruded by additional quartz veins. Recoveries and RQDs are high, generally greater than 90 percent, through these healed shears, with permeabilities on the order of less than 10'6 cm/sec. The second type of shear found in both surface exposures and boreholes consists of unhealed breccia and gouge. The gouge is light gray to tan clay. Breccia consists of coarse to fine sand size fragments in a clay and/or silt matrix. Gouge and breccia are generally soft and fri- able, and occur in zones normally 0.1 to 1 foot wide. The thickest gouge and breccia was up to 3 feet in BH-7. Chlorite/talc and carbonate mineralization are associated with the shears. Slickensides are common and occur on the chlorite surfaces. These shears are generally asso- ciated with fracture zones. Where they are coincident, they have been denoted as shear/fracture zones. - Fracture Zones Fracture zones are areas of very close to closely spaced (less than 1 foot) jointed rock. Fracture zones are found in both outcrop and boreholes. As with the shears, both healed and unhealed fracture zones are common. In outcrop, both healed and unhealed fracture zones range from less than 1 foot up to 20 feet wide, but are gener- ally less than 5 feet. In the boreholes, fracture zones range from less than 1 foot to 60 feet but are generally ACBES 72 less than 5 feet as measured along borehole length. Healed fracture zones consist of irregular and discontin- uous fractures filled with quartz or carbonate minerali- zation. These zones are tight with permeabilities con- sistent with the surrounding rock. Unhealed fracture zones often have chlorite/talc, carbonate, or quartz on joint surfaces. Fracture zones tend to form topographic lows or gullies because of their erodibility. Gullies formed by some of these zones are shown on an aerial photograph of the site (Figure 7.12). Significant Geoloqic Features The Devil Canyon site has several significant geologic fea- tures which include shears, fracture zones, dikes, and open joints. Dikes and joints have been discussed in previous sections. The features discussed in this section are: (a) northeast trending shears in the saddle dam area (GF 1); (b) a series of northwest trending shears and fracture zones (GF 2 through GF 11); (c) the bedrock low beneath Borrow Site G; and (d) rock conditions beneath the Susitna River (Figures 7.3). - Geologic Feature GF 1 GF 1 is located on the south bank approximately 1,000 feet from the Susitna River (Figure 7.3). The shear has been mapped as passing beneath the proposed saddle dam nearly parallel to the Susitna River. The shear was first postulated by USBR (28 and 57) based on several vertical boreholes (DH-6 and DH-15) which penetrated sheared and fractured bedrock in this area (Figure 7.3). The shear was inferred to strike northeastward along a topograhic depression beneath two ponds and dip northwest towards the river. Subsequent seismic refraction work by the COE (39 and 45) in this area indicated a bedrock low (Figure 5.2) and a low seismic velocity zone in the bedrock across this feature (Figure 7.10). These low velocities (10,700 feet per second) occurred from 25 feet south of DH-4 to 60 feet south of DH-7, whereas veloci- ties at the north and south ends of the line were about 19,000 feet per second. During this investigation, three additional seismic lines (SL 80-12, -13 and -15) were run and two boreholes (BH-4 and BH-7) drilled to define the nature and extent of this shear zone (Appendix B and H). The seismic data confirmed the existence of a bedrock low in this region with the top of bedrock being as deep as Elevation 1250 (Appendix H). A low seismic bedrock velocity (12,380 feet per second) was interpreted along SL 80-13 beneath the pond. Bedrock velocities to the „ RCBa f north and south of this anomally were on the order of 16,800 and 18,800 fps, respectively. BH-4 and BH-7 were angle drilled southward and northward, respectively, to intersect this postulated shear. No shearing was en- countered in BH-4; however, BH-7 intersected a highly sheared and fractured argillite and graywacke from a hole depth of 87.0 to 130.7 feet. Zones of breccia and gouge up to 3 feet wide were encountered within a 40-foot wide fracture zone. Rock fragments were coated with chlorite and slickensides. Core recoveries were low and RQDs were 0 percent (Figure 7.6). Permeabilities in this zone were generally 10-4 cm/sec. Based on this borehole data, the dip of the shear is inferred to be parallel or sub - parallel to the bedding/foliation at approximately 65' to the south. It is likely that the shear follows the topo- graphic low to the west as shown on Figure 7.3. The ex- tent of the shear in an easterly direction is unknown. Additional work will be required in subsequent phases to more accurately delineate the extent of this feature. - Northwest Trending Shears and Fracture Zones A series of northwest trending shears and fracture zones, parallel to Joint Set I, were mapped in the damsite area (Figure 7.3). Many of the shears previously identified by the USBR were found to be mafic or felsic dikes of which some have associated shearing at the contact (Sec- tion 7.1[b]Eiv]). Figure 7.12 is an aerial view of the site on which the locations of some of these features are indicated. GF 2 is a shear and fracture zone that ranges from 15 to 18 feet wide as mapped at river level on the north bank (Figure 7.3). The zone trends 345' with an 800 northeast dip. Based on the projection of its strike and dip, GF 2 was correlated with a fracture zone in BH-2 at 601.2 to 621.0 feet (Figure 7.5). This zone consists of planar, smooth joints and irregular, discontinuous fractures. Many joints and fractures are coated with talc and carbonate. RQDs in the zone range from 75 per- cent to 90 percent with low permeabilities (less than 10-5 cm/sec). No evidence of GF 2 could be found on the south bank. GF 3 (Figure 7.3) parallels GF 2 approximately 100 feet to the west. As mapped on the north bank, GF 3 is 5 to 10 feet wide and coincides with mafic dike M 2. GF 3 has been tentatively correlated with a fracture zone in the upper portion of BH-1 from 80.1 to 108.5 feet. This shear/fracture zone consists of irregular and discontinu- ous joints and fractures which are carbonate coated and iron oxide stained with traces of silt and slickensides. axis ,.,a RQDs are very low, ranging from 8 to 57 percent with per- meabilities on the order of 10-4 to 10-5 cm/sec. On the north bank, GF 3 has been correlated with a shear/ fracture zone in a narrow gully. Shear/fracture zone GF 4 occurs about 350 feet downstream from GF 3 (Figure 7.3). This zone contains up to 1.5 feet of clay gouge. This zone may correlate with a bed- rock dropoff on seismic line SL 81-22. GF 4 projects northward across the river into a gully where it appears to splay. This splayed zone may correlate with a small shear/fracture zone near the bottom of BH-1 from borehole depths of 678.9 to 683.8. This zone consists of planar, smooth joints with irregular and discontinuous fractures. RQDs are low (25 percent and 60 percent); however, per- meability measurements are 10-6 cm/sec indicating the general tightness of the zone. Shear/fracture zone GF 5 is a small, apparently discon- tinuous zone located on the north bank near DH-13 (Figure 7.3). The zone occurs in a narrow gully with very close to close spaced northwest -trending joints. GF 5 was also intersected in DH-13 at a borehole depth of 93.3 feet where it is partially healed with carbonate, and quartz RQDs in this zone are 0 percent. Shear/fracture zone GF 6 was mapped in a deep gully on the south bank of the river (Figure 7.12). The zone trends northwest, dipping 750 to the west. GF 6 consists of a 2-to-3 foot -wide fracture zone with 3 to 4 inches of light gray to black clay gouge. This zone was inter- sected by DH-10 between 101.1 and 117.8 feet. No gouge was recovered; however, the joints have occasional slick- ensides and are chlorite coated. Minor carbonate and iron oxide is also present in the zone. RQDs are gener- ally zero throughout the zone. No pressure testing was done in the borehole; however, reports by the USBR showed no severe water loss during drilling. GF 6 has been ten- tatively projected to the north bank. Downstream from GF 6, four other northwest trending shear/fracture zones (GF 7, 8, 9, and 10) had been pre- viously mapped by the USSR. No evidence for these zones could be found during the 1980-81 mapping program. How- ever, the mapping in this area was performed during winter when many areas were covered with snow and ice. -1s ACRES - Bedrock Low Beneath Borrow Site G Seismic lines SW-15 and SW-16 performed by Shannon & Wil- son (39) for the COE in Borrow Site G showed a marked dropoff in bedrock elevation and seismic velocities along the east end of the seismic lines (Figures 7.2 and 7.9). As noted from the figures, the bedrock surface is in- ferred in this area to drop off more than 200 feet along a west to east traverse across Borrow Site G. Land access restriction imposed during this study prohibited any further investigation of this area. Possible explan- ations for this apparent anamalous bedrock dropoff could be attributed to misinterpretation of the seismic data wherein the lower velocity material could be either a highly fractured rock in lieu of till or offset of the rock surface by faulting. The latter interpretation is unlikely in that the work performed by Woodward -Clyde Consultants (60) for this project evaluated lineaments in this area and concluded that there was no compelling evi- dence for a fault. Further exploration will be required in subsequent phases of the investigation to better define the bedrock condi- tions in this area. --Bedrock Conditions Beneath Susitna River The presence of geologic structures beneath the present course of the Susitna River was examined by both the USBR (51) and Acres. A series of angle boreholes were drilled by the USBR from both the north and south banks at river level (Figure 5.2). Several of these boreholes (DH-11, -11A, -11B, -11C, -14 and -14A) "daylighted" into the river requiring them to be redrilled at a steeper angle. RQDs in most of the river holes was generally greater than 60 percent with permeabilities less than 10-4 cm/sec. These low values are primarily attributed to open joints and frac- tures in the shallow weathered bedrock zone. Minor fracture and shear zones were encountered in sever- al of the boreholes (DH-11 and DH-14 series and BH-5a); however, these were limited in nature and could not be correlated between borings. No indication was found from the investigation to suggest either faulting or fractur- ing parallel to the course of the river. RCRfS ,-1e To support this conclusion, the dikes on both abutments were surveyed and showed no noticeable offsets across the river. (v) Geolog Along Proposed Long Tailrace Tunnel Introduction This section discusses the lithology and structure along the proposed long tailrace tunnel for the Devil Canyon damsite. Reconnaissance mapping was done along the Sus- itna River from about 2,500 feet to 10,000 feet down- stream from the site. Rock exposures are nearly continu- ous from the damsite to the bend in the river where the proposed portal area is located (Figure 7.14). From that point downstream, outcrops are scattered and poorly ex- posed. - Lithology As in the area of the main dam, the lithology along the proposed tailrace consists of interbedded argillite and graywacke which have been intruded by mafic and felsic dikes. The argillite is medium to dark gray, very fine to fine grained argillaceous rock with occasional grains of fine to medium sand. The graywacke is light to medium gray and consists of fine to medium grain -size grains in a very fine grained argillaceous matrix. The interbeds of argillite and graywacke are generally 6 inches thick. Contacts between beds are sharp and tight. Bedding is parallel to a weakly developed foliation. Bedding/foliation strikes generally northeast with moder- ate dips to the southeast (Figure 7.14). This secondary foliation (which is poorly developed at the damsite) is locally well developed near the proposed tunnel portal. The secondary foliation, strikes nearly north -south with high angle dips to the northwest. The argillite and graywacke have been intruded by numerous quartz veins and stringers as at the damsite (Section 7.1Lb]). Felsic and mafic dikes were mapped in outcrops along the river and to the north of the tunnel route. The litho - logy and structure of these dikes are similar to those found at the damsite. The felsic dikes consist of two varieties: rhyolite and granodiorite. The rhyolite dikes are light yellowish gray to gray. The texture is aphani- tic to fine grained with fine to medium grained quartz phenocrysts. The granodiorite dikes are primarily medium grained plagioclase phenocyrsts in a fine grained ground - mass of plagioclase, orthoclase, biotite and quartz. The 7-17 RCNIS felsic dikes are generally slightly to moderately weathered, medium hard, with very close to closely spaced joints. Iron oxide staining is common. Widths are gen- erally 10 to 20 feet. Contacts with argillite and gray- wacke are generally fractured and/or sheared. Up to 3- foot--wide contact metamorphic zones are common in the adjacent argillite and graywacke. The felsic dikes strike northwest and northeast. Mafic dikes are generally dark green to dark gray. These dikes are fresh to slightly weathered and hard. Mafic dikes are composed of feldspar in a fibrous groundmass with accessory pyroxene, biotite, hornblende, and cal- cite. These dikes are generally 2 to 10 feet wide and trend northwest with high angle to vertical dips. Like the felsic dikes, the mafic dike contacts are generally sheared and/or fractured. Joint spacing is very close to closely spaced. A nearly 200-foot-wide outcrop of granodiorite was mapped approximately 4,000 feet north of the river at Elevation 2100. It is not known whether this feature is a large dike or part of the granodiorite pluton surrounding the site (Section 4). - StrurtiirPt Joint sets and shear/fracture zones similar to those mapped at the damsite are likely to occur along the tail- race tunnel. The four joint sets identified at the damsite (Section 7.1[c]) continue downstream; however, variations in ori- entation and dip occur. Table 7.3 is a list of joint characteristics for joints along the tailrace tunnel. Joint Set I is northwest trending with a moderate to high angle dips to the northeast and southwest. The average strike and dip of this set in the tailrace area is 325' and 70" northeast, respectively, which differs slightly from its average orientation in the damsite of 3400 and 80' northeast. Spacings are highly variable but average about 1.5 feet. The river flows parallel to this set in the vicinity of the outlet portal. Joint Set II includes joints parallel and subparallel to the bedding/foliation planes. This set strikes 065' with moderate (60°) dips to the southeast. The strike is essentially the same as at the damsite, although the dip is slightly steeper. ACRE3 71a Joint Set III strikes nearly north -south at an average of 022°. Dips are variable from 63' east to 84' west. The strike of Set III is similar to that found on the south bank of the damsite; but about 30' more northerly than the average strike found on the north bank (Table 7.2). Dips are generally similar to those at the damsite. Set III joints are well developed in the vicinity of the out- let portal. Joint Set IV consists of low -angle (dipping less than 401 joints of various orientations. Those in the vicin- ity of the tailrace tunnel are similar to those described in Section 7.1 (c) and Table 7.2. Although no shears or fracture zones were found during the reconnaissance mapping downstream from the damsite, it is anticipated that several such features will be en- countered along the tunnel. These smears and fracture zones will likely be less than 10 feet wide and spaced from 300 to 500 feet apart (Section 7.1[c]). (d) Rock Quality Designation The Rock Quality Designation (RQD) for all cored holes drilled by Acres and the USBR are presented on the Summary Logs in Appendix C. A tabulation of the RQD values with hole depth is contained in Tables 7.4 and 7.5. The overall nature of Devil Canyon rock is that of a very hard, brittle rock. Little difference is found in rock quality between the argillite and graywacke. Based on analysis of the RQD values, the rock is classified as "good" to "excellent." Overall average RQD for 12 boreholes drilled previously by the USBR and 7 boreholes by Acres during 1980-81 in the damsite area is 76 percent (Table 7.4). For the most part, the USBR cores show slightly lower RQDs than the rock drilled by Acres. This is like- ly attributed to several factors including poor drilling problems and core breakage during handling and transport. Similarly, most of the USBR cores were shallow holes (C150 feet) and reflect lower RQDs found in near surface weathered and fractured zones. As noted in Table 7.4, RQD values tend to increase with depth. The depth of weathering varies from near surface to 80 feet deep and is mainly evidenced by a high degree of fracturing with joint staining and minor mineralization. Lower RQD values were encountered in BH-3 (Table 7.4). This hole was drilled on the left abutment and inclined northward to inter- sect a series of open joints along the gorge walls. Other zones of lower RQDs were found in sheared and highly fractured rock, i.e., BH-7 (Appendix C). ,v RCNI9 In summary, over 70 percent of the rock drilled during the 1980-81 program had RQD values ranging from 75 to 100 percent with only 8 percent having RQDs less than 25 percent. The intact rock at Devil Canyon has been classified as high strength with an average modulus ratio and classification of BM (14,16). (e) Rock Properties Representative NQ (1.77) core samples of agrillite and graywacke were selected from BH-I, 2, 3, 5a, 5b, and 7 (Figure 7.15). Results of the testing program are presented in Tables 7.6 and 7.7 and are discussed below. Representative photos of rock tests are shown in Figure 7.15. (i) Unit Weight Dry unit weights, measured in conjunction with both tensile and compressive strength tests, gave an average unit weight of 170 pcf for both the argillite and graywacke. (ii) Static Elastic Properties Elastic properties were measured using electronic strain gages bonded onto the sample in axial and circumferentially directions. Stress, diametric strain, and volumetric strain were computed and plotted against axial strain from which secant modulus, tangent modulus at 50 percent failure stress, and Poisson's Ratio were determined. Results are presented in Figure 7.16. An average of all test results show: Rock Type No. of Tests Argillite 7 Graywacke 6 Combined 13 (iii) Dynamic Elastic Properties Static Modulus (x 106-psi ) 9.74 10.32 10.0 Poisson's Ratio 0.21 0.19 0.20 Compressional (Vp) and shear (Vs) wave velocities in fps for both argillite and graywacke were determined and dynamic moduli and Poisson's Ratio computed. Results aver- aged: Rock Type Number of Tests Vp (fps)' Vs (fps) Argillite 2 20,015 11,520 Graywacke 2 19,280 11,310 pCGS ,._0 An average of all test results show: Dynamic MoPl us Rock Type Number of Tests x10psi) Argillite 6 10.62 Graywacke 5 11.09 Combined 11 10.8 (iv) Direct Shear Tests Dynami c Poisson's Ratio 0.13 0.22 0.17 The following types of direct shear tests were performed on both argillite and graywacke: - natural discontinuity - polished rock on rock - polished rock on mortar Test results are plotted in Figure 7.17. A summary of the results is as follows: Argillite - natural discontinuity - polished rock on rock, dry - polished rock on mortar, dry Graywacke - natural discontinuity - natural discontinuity using inferred co- hesive intercept - polished rock on rock, dry - polished rock on rock, wet - polished rock on mortar, dry - polished rock on mortar, dry with bond broken with inferred cohesive intercept 7-21 Peak V Residual C(psi) 27.50 230 0 21.50 19.50 0 310 250 0 250 230 0 -- 220 6 250 230 0 21.50 18" 0 160 100 0 200 150 0 31" 270 90 -- 270 6 RCB6 Polished rock on rock tests give a material's lowest fric- tion angle. This angle ignores effects of natural surface undulations or roughness. Therefore, a "waviness angle" is applied to obtain a more representative value for design. This "waviness angle" is based to a large degree on ob- served field conditions of natural joint surface and site geology. For this study, natural surface friction angles were based on a slick, chloritized, natural discontinuity in argillite and a smooth, planar, partially open natural joint in gray- wacke. These discontinuities, which represent unfavorable conditions, have been considered as lower limit values. Shear strength of rock against concrete was simulated by sliding a polished graywacke and argillite core against mortar. As noted above, these results gave peak 0 values of 30' and 0 residual between 20' and 26°. It should be noted that normal rock foundations are rough, giving fric- tion angles of 35' or higher. As noted in Figure 7.17, lower friction angles were obtain- ed under the 150 psi normal load test for rock on mortar tests. The 150 psi load test is the highest load in a se- quence of three tests performed on the same sample. There- fore, it is likely that the previous shear tests performed on the sample resulted in the surfaces degrading and approaching a residual characteristic, thereby giving a lower result. Data plots for direct shear tests of polished rock surfaces show an oscillation of the shear load with displacement of the rock surface. This indicates that the movement of the rock surface, relative to each other, was not uniform. The shear stress reaches a peak after which movement takes place. The shear stress drops to a residual value but then builds up to a subsequent peak value. This cycle repeats itself over the full extent of the displacement range. The upper and lower bounds of the plotted points are be- lieved to represent the peak and residual friction angles for polished surfaces. Direct shear test data presented here should be considered only as a preliminary estimate of design parameters. The final determination of design friction angles will require a comprehensive knowledge of the geologic structure and friction angles for each discontinuity as they relate to each engineered facility. (v) 'Compressive Strength Testing Compressive strengths were measured by both unconfined com- pression and point loading methods. - Unconfined Compression Results of unconfined compressive strength tests show: Number of High Low Mean + Standard Rock Type Tests JEsilsi Deviation Jesil Argillite 21 32,940 8,017 19,792 + 6,533 Graywacke 16 36,570 4,066* 22,755 + 8,600 *Failure along healed joints Both rock types are variable in strength with higher strengths reflecting "intact" rock and lower strengths reflecting cores with inherent weaknesses such as folia- tion, healed joints, etc. The foliation within the rock makes the rock slightly anisotropic. Frequency plots (Figure 7.18) show 90 percent of the combined test results are greater than 12,000 psi and, assuming a nor- mal distribution, approximately 70 percent of all tests fall within the standard deviation, i.e., between 12,925 and 28,235 psi. - Point Load Testing Rock strength for BH-1 and BH-2 core was tested at 15- to 20-foot intervals using a Terremetrics T-500 point load tester. Statistical data analysis give: Mean + Standard Rock Type Number of Tests Deviation (psis Graywacke 33 21,973 + 5,745 Interbedded argi l lite and graywacke 163 21,579 + 6,752 All tests 338 22,393 + 6,842 Frequency plots are presented as Figure 7.19. In compari- son with the unconfined test, these tests gave slightly higher values. The probable cause for this is that rock strength is proportional to the physical dimensions of the tested sample. For unconfined compression tests, lower strengths are generally found for the larger diameter sam- ples (23). Similar effects are also noted in the Watana test results. 2= RCBf3 Both types of tests, however, indicate a high strength rock. Combining the compressive strength and elastic prop- erties for both the argillite and graywacke gives a high strength rock with an average static modulus to compressive strength ratio (BM)(14). (vi) Tensile Strength Number of High Low Mean + Standard Rock Type Tests (psi) JLs.jj (psi)Deviation (psi) Argillite 4 3944 3018 3410 + 390 Graywacke 5 5071 1471 2960 + 1515 Argillite test results (Brazilian Split) were relatively uniform while graywacke results were variable. These tests show high intact rock tensile strength, which implies high intact rock shear strengths. (vii) Summar The rock test results presented in this section are consid- ered adequate for preliminary design purposes. Extensive geotechnical work including drilling, down hole testing, geophysics, exploratory adits, laboratory and in situ test- ing, will be required before the final design parameters can be determined for each structure. However, tests per- formed during this, as well as previous studies, show the rock to be of excellent quality for constructing both sur- face and subsurface facilities at Devil Canyon. (f) Rock Permeability Water pressure tests were carried out in all seven holes drilled by Acres. Results of the permeability tests are shown graphically on the summary logs in Appendix C with test results tabulated in Appendix E. At several locations (BH-4 at depths 90 to 140 feet), tests could not be completed because of equipment problems. Water pressure tests performed by the USBR and Acres (Section 5) confirm that rock permeability at the Devil Canyon damsite is con- trolled by the degree of jointing, fracturing, and weathering within the bedrock. The rock permeability does not vary significantly within the site area, generally ranging at 1 x 10-4 and 1 x 10-6 cm/sec with lower permeabilities generally at depth and higher permeabil- ities in the more highly fractured rock zones. A summary of perm- eability with depth is shown in Figure 7.20. Permafrost has not been observed at Devil Canyon and therefore will not affect perme- ability. �CBES ,-_. (g) Groundwater The damsite is located in a "young" geomorphic terrain which is characterized by high relief and immature drainage systems. As stated in Section 7.1 (f), groundwater flows are confined to the fractures and joints within the bedrock. Based on piezometer readings and water level readings taken during drilling, it appears that the groundwater table is a subdued replica of the surface topography with groundwater gradients steeper near the river and lakes. Water level readings performed in BH--1 and BH-2 have given relatively constant levels during 1980--81 with depths of approximately 150 feet and 0 feet beneath the ground surface, respectively. Other readings taken in BH-4 and BH-7 on the left abutment correspond closely with the lake level. Groundwater levels are expected to be variable throughout the site, controlled principally by the extent of fracturing within the rock mass. Some seeps have been noted in the gorge walls indicating ground- water migration through open joints and fractures. These seeps, however, are relatively small. No seeps were noted above the break in slope. (h) Permafrost (i) General Climatological data collected during 1980-81 near the site indicate that the damsite average temperature may be slightly above freezing, about 1°C. According to published data, the Devil Canyon site is within a zone of discontinu- ous permafrost (19). The localized climatic conditions at the site may, however, be more severe than suggested because of the high relief and the deep gorge which receives very little sunlight. Despite the apparent severe weather conditions, no direct evidence has been found in or around the damsite to suggest the presence of significant amounts of permafrost (36). (ii) Damsite During drilling and test pitting, special care was taken to observe any evidence of permafrost, and none was found. Thermistor strings 250 feet long were installed in BH-I, 2, and 4 (Figure 7.19) and showed excellent stabilization in BH-1 and 2 and fair -to -good stabilization in BH-4. The ground temperatures were all recorded between 1.P C and 4.4°C at depth. BH-1 and BH-2 on the north abutment have very similar readings, showing the depth of annual ampli- tude reaching a depth of approximately 50 feet, with mini- mum ground temperatures of 1.7 to 2.1°C occurring from -25 �CBIS E 60 to 130 feet below surface topography. Below that depth, both holes show a consistent warming trend that probably reflects the natural geothermal gradient. Geothermal grad- ients appear to be average, showing about 1% per 300 feet (1°F per 166 feet) (24). (iii) Emergency Spillway The emergency spillway area is not expected to have any permafrost in rock, and only sporatic frost in the overbur- den. In the downstream outlet area, where overburden may reach 75 feet or more, remnant permafrost lenses in the till may be expected. Annual frost penetration is expected to be about 10 to 15 feet. ( i v ) Saddle Dam The thermal regime in the saddle dam area is similar to the damsite, as shown by the thermistor log of BH-4 (Figure 7.21). Based on these data and auger drilling in this area, no evidence of permafrost was found. Because BH-4 was angled under the lake, the thermistor string extends only approximately 175 feet below the top of the alluvium. The apparent 1.5° variation in downhole temperature (4.4% in August to a low of 3.1° in December) could reflect changes in lake temperature through the year as water mig- rated from the lake through open joints and fractures around this section of borehole. The apparent subzero tem- peratures at depth were noted as erratic and inconsistent when the readings were taken. Therefore, the May 24, 1981 reading at 200 feet has been neglected. Likewise, the erratic and fluctuating readings on one of the 250-foot- depth thermistors, with total failure on the latest set of readings, make this a suspect data point (Figure 7.21). Additional instrumentation will be required in this area to further -define the subsurface thermal regime. (v) Camp Areas Based on auger holes and USBR investigations, permafrost should be expected to occur in the proposed camp area as localized small lenses or zones within the overburden. Annual frost heaving can be expected in the overburden. Access Roads Access and construction roads can be expected to encounter scattered permafrost lenses and pockets. The annual frost penetration is likely to cause heaving in much of the allu- ACHES , 26 vial material, particularly the clayey moraines and thin outwash deposits. Groundwater flow, where encountered, may cause seasonal "icing," which could disrupt drainage. Fur- ther investigations of permafrost and foundation conditions along the proposed access roads will be required in subse- quent studies. 7.2 - Borrow and Quarry Material The borrow investigations at Devil Canyon were performed with the use of auger drilling, test trenching, field mapping, seismic refraction and air photo interpretation as described in Section 5. The objectives of the 1980-81 investigation were to: - define the limits of previously identified borrow sites; - identify new borrow sites; and - determine material properties and volumes. The information collected during this investigation has been combined with data from previous investigations to develop a comprehensive data base for each borrow and quarry site. One borrow site and one quarry site were identified for this study. Borrow Site G was investigated as a source for concrete aggregate and Quarry Site K for rockfill. Des- pite detailed reconnaissance mapping around the site, no local source for impervious or semipervious material could be found. As a result, Borrow Site D (Section 6.3) has been delineated as the principal source for this material. Further investigations may identify a more locally available source. The following sections provide a detailed discussion of the borrow and quarry sites for the Devil Canyon development. (a) Borrow Site G ( i ) Proposed Use Borrow Site G was previously identified by the USBR and in- vestigated to a limited extent by the COE (45,51) as a primary source for concrete aggregate. Because of its close proximity to the damsite and apparent large volume of material, it became a principal area for investigation dur- ing the 1980-81 program. The scope of the 1980-81 investi- gation in this borrow site is discussed in Section 5 and shown in Figure 7.22. (ii) Location and Geology Borrow Site G is located approximately 1,000 feet upstream from the proposed damsite. The area delineated as Borrow Site G is a large flat fan or terrace that extends outward from the south bank of the river for a distance of approxi- mately 2,000 feet. The site extends for a distance of ,.,, ACBE� approximately 2,000 feet. The site extends for a distance of approximately 1,200 feet east -west (Figure 7.22). Cheechako Creek exits from a gorge and discharges into the Susitna River at the eastern edge of the borrow site. The fan is generally flat -lying at Elevation 1000, approximate- ly 80 feet above river level. Higher terrace levels that form part of the borrow site are found along the southern j edge of the site above Elevation 1100. ! Vegetation is scattered brush with mixed deciduous trees found on the floodplain and fan portions. On the southern hillside portion of the borrow site, heavy vegetation is evident with dense trees and underbrush (Figure 7.22). The ground cover averages up to 0.5 foot in thickness and is generally underlain by 1 to a maximum of 6.5 feet of silts and silty sands. This silt layer averages 1.5 feet thick on the flat -lying deposits, and up to 2 feet thick on the hillsides above Elevation 950. No groundwater was encountered in any of the explorations. The high permeability of the material provides for rapid drainage of the water to the river. Annual frost penetra- tion can be expected to be from 6 to 15 feet. No perma- frost has been encountered in the area. The borrow material has been classified into four basic types, based on the interpretation of field mapping and ex- plorations. The four types of material or zones, as iden- tified on the map (Figure 7.22), are: Susitna River allu- vial gravels and sand (Zone I), ancient terraces (Zone II), Cheechako Creek alluvium (Zone III), and talus (Zone IV). The large fan deposits are a combination of rounded allu- vial fan and river terrace gravels composed of various vol- canic and metamorphic rocks and some sedimentary rock pebbles. This material is well -washed alluvial material. Zone I has been divided into two subzones, the upper (Ia) being generally a sandy layer about 20 feet thick, under- lain by a thick sandy gravel (Ib) that has been inferred by seismic refraction (39) to extend well below river level. A section on the west side of the fan is shown in Figure 7.22. The ancient terraces (Zone II) are probably similar in origin to Zone I, but being higher on the banks, they likely represent a higher river energy environment; hence, the gradations are expected to be less uniform with more cobble size material. The material in Zones I and II is believed to be generally uniform over a wide range and depth with a trend towards coarser materials with depth. The Cheechako Creek alluvium (Zone III) is bouldery with some angular particles. [ACNIS� , =a The talus (Zone IV) comprises argillite and graywacke derived from the bluffs immediately above the fan. This is composed of the same type rock as the damsite. (iii) Reserves The borrow site quantities were broken down into zones as shown on the typical sections based on the exploration logs and test trench sections shown in Appendix G (Figure 7.22). Based on these data, the quantities of fine sands and gravels in Zones Ia and Ib above river level have been es- timated to be approximately 1.1 and 1.9 mcy, respectively. Additional quantities could be obtained by excavating below river level. The quantity of material in Zone II is tenta- tively estimated to be approximately 2 mcy. This, however, has been based on an inferred depth to bedrock. If bedrock is shallower than estimated, this quantity would be less. Zone III material is estimated at 1.1 mcy, while Zone IV is 55,000 mcy. Zone IV quantities are too small to warrant consideration as a borrow material. An estimate of the total quantity of borrow material is about 3 mcy with an additional 3 mcy potentially available from inferred resources. The increase in river level caused by diversion during construction may affect the quantity of available material from this site. Therefore, further work will be required in subsequent studies to accurately determine available quantities and methods and schedules for excavation. (iv) Engineering Properties A detailed petrologic description of the material was per- formed by the USBR (52) and Kachadoorian (29) and, there- fore, have not been repeated here. In summary, the deposit is a gravel and sand source composed of rounded granitic and volcanic gravels, with a few boulders up to 3 feet in diameter. Deteriorated materials comprise about 8 to 10 percent of the samples. Testing performed by the USBR (52) indicates that about 2 to 4 percent of the material was considered adverse material for concrete aggregate. Results of the laboratory tests performed for the project are summarized in Table 7.8. A composite grain size curve showing the wide range of gradations in Borrow Site G is shown in Figure 7.24. A more detailed breakdown of the _9 RCflf3 various stratigraphic unit gradations is shown in Figure 7.25. Units identified in Figure 7.25 correspond with those units mapped in the test trenches (Appendix G). In summary, two distinct grain sizes are found in the site: (1) from the auger holes (Unit D), a fairly uniform, well sorted coarse sand with low fine content and (2) from the test trenches (Unit Z), a fairly well -graded gravelly sand averaging 10 percent passing No. 22 sieve. The principal reason that the auger drilling did not encounter the coarser material is likely reflective of the sampling tech- nique where the auger sampling could not recover the coarser fractions. A finer silty layer (Unit C) overlies much of the borrow site. Samples from the higher elevations are more sandy than those from the fan area. Based on observed conditions, the grain sizes from the trenches are considered more representative of the material in Borrow Site G at depth, while the finer fraction repre- sents the near surface material. The specific gravity testing gave values ranging between 2.33 and 2.87 with natural water content ranging from a low of 3.7 to a high of 30.9 percent with an average of around 12 to 15 percent. Dry and wet density ranges from a low of 90 through 143 and 95 through 153 pcf, respectively. (b) Quarry Site K (i) Proposed Use Quarry Site K was identified during this study as a source for rockfill for the construction of the proposed saddle dam on the left abutment. (ii) Location and Geology The proposed quarry site is approximately 5,300 feet south of the saddle damsite, at approximate Elevation 1900 (Figure 7.26). The site consists of an east -west face of exposed rock cliffs extending to 200 feet in height. Vege- tation is limited to tundra and scattered scrub trees. Drainage in the area is excellent with runoff around the proposed quarry site being diverted to the north and east toward Cheechako Creek. The groundwater table is expected to be low and confined to open fractures and shears. ACBES 7_0 The bedrock is a white -gray to pink -gray, medium grained, biotite granodiorite similar to that at the Watana damsite (Section 6). The rock has undergone slight metamorphism and contains inclusions of the argillite country rock with local gneissic texture. The rock is generally massive and blocky, as evidenced by large, blocky, talus slopes at the base of the cliffs. The rock is probably part of a larger batholith of probable Tertiary age which has intruded the sedimentary rocks at the damsite (Section 4). (iii) Reserves The limits that have been defined for the quarry site (Figure 7.26) have been based on rock exposure. Additional material covered by shallow overburden is likely to be available, if required. However, since the need for rock fill is expected to be small, no attempt was made to extend the quarry site to its maximum limits. The primary quarry site is east of Cheechako Creek (Figure 7.26). This area was selected primarily because of its close proximity to the damsite and high cliff faces which is conducive to rapid quarrying. The low area west of the site was not included because of possible poor quality sheared rock. A secondary ( backup) quarry source ( Figure 7.26) was deline- ated west of the primary site. Because of the extensive exposure of excellent quality rock in this area, additional exploration was not considered necessary for this study. The approximate volume of rock determined to be available in the primary site is about 2.5 mcy per 50 feet of exca- vated depth, or approximately 7.5 mcy within about a 30- acre area. The alternative backup site to the west of Quarry K has been estimated to contain an additional 35 mcy for 150 feet of depth, covering some 145 acres. (iv) Engineering Properties The granodiorite was selected over the more locally avail- able argillite and graywacke because of the uncertainty about the durability of the argillite and graywacke under severe climatic conditions. The properties of the granodiorite are expected to be simi- lar to those found at the Watana damsite (Section 6.lEe]). Freeze -thaw and wet -drying (absorption) tests performed on rock types similar to those found on Quarry K by the COE (49) exhibited freeze -thaw losses of <1 percent at 200 cycles and absorption losses of 0.3 percent. Both tests showed the rock to be extremely sound and competent. „ ACRES TABLE 7.1: DEVIL CANYON SEISMIC VELOCITY CORRELATIONS VELOCITY Feet per Second (fps) INFERRED MATERIAL Shallow sands, gravels, soil - dry surficial including denser gravels, sand, talus and slopewash, generally well drained. 3000-4000 Dry gravels and gravelly sand could include frozen alluvium and slopewash if present. 4000-5000 Saturated and/or frozen (if present) material from classifica- tions above. 5000-7000 Saturated coarse materiels including gravels, outwash, till. 7000-9000 Dense gravels, tills, reworked tills and passible highly weathered bedrock. 9000-12000 Rock, highly weathered, open fractured and/or sheared. 12000-14000 Rock, weathered, fractured or sheered but not necessarily openly fractured. 14000-17000 Bedrock, slightly weathered. 17000-19000+ Bedrock, very sound, tight, only slightly weathered. Reference: 39, 51, 57, and 59. 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LC � � � � c N a-d rV] _j CL N m m a) U O O O N 0 O O fr m 4 al P a] C SO a7 °t7,a o H d 8 Gt} L� e n (00 O O H H VI U U V} U fQS1 U ca s a Z C Q LO C 0 k 1-[ b m a1 L lTr m r 3 > t7l 0)01 U F, o � k 0 a Co 7 -�I (� N N 7 0 0 p 1J 1J 'H •H cCv -Q N O �UNp t0 f) UO D � E --I 5 > N t O al i N C � I ro k o n1 l,] LLI z En e o CY 0 0 > I• x ul w vE to 0 a) v� 0 o u 5o z uWi C3 ►� J� M a ID > CO M O o e in Lr) b M [] I E U c N C co N C3 O N H LO N i TABLE 7.4: DEVIL CANYON RQD SUMMARY Borehole* - $ _ - a - - - - * - c - * a - * - a - a c Ground Surface E1.(ft) 1415 1214 1405 1353 980 980 1335 1419.7 1448.3 1424 1425 893 896 896 912 903 902 903 Total Rock Top of Rock El. (ft) 1404 1212 -- 1346 -- -- -- 1419.7 1448.3 1424 1425 893 096 896 912 903 902 903 Drilled - Borehole Cip 670 600 32° 60° 450 45° 500 45° 30° 45° 520 570 60° 45° 450 37° 530 600 55° Average RQD Vertical Depth (ft) RQD Rock 0'-50' Drilled (ft) 52.7 60.2 94.3 58.2 72.5 71.8 66.2 72.5 99.3 72.5 63.1 31.7 50.0 73.1 49.3 73.9 45.4 60.0 62.0 1228.7 RQao' 66 0 79% 82% 87% 64 4 630 619d 67 . 69 n 770 63 o 67DO' °' 65,° 79,0 % o' 28,° 5b.o % 750 720 0' 5B,° °' 68,° 50'-150' " 107.0 113.4 187.6 113.0 138.7 128.5 134.8 42.2 49.2 12.5 57.6 91.5 40.7 48.6 59.7 53.2 82.1 19.3 1488.4 65 0 72'u 7b°o 98e. 79In 82o b0,o 60°0 $$% 100 50°6 54% 71°0 82°0 11,°a' 73 °0 7190 17°0 690 150'-250' It 108.6 116.4 101.7 117.9 143.2 141.2 729.2 $7'o 9040 4690 $9Yo 81A BB90 81°u 250'-350' " 111.1 115.1 114.3 142.2 143.4 626.1 86 0 07 u 900 88 n 85% 87o 350' -450' 110.0 117.2 84.5 101.3 413.0 90% 94100' 95 0 84 4 910 450'-550' " 107.7 116.2 223.9 96% 85,"o 90% 550'-650' it 106.6 15.0 121.6 B9110 960 90,°0' 650'-750' " 34.5 34.5 B5°0, 1 1 1 1 1 B5% Total Hole Length (ft) 738.4 653.5 383.6 468.7 597.9 200.3 1 485.6 114.7 148.5 85.0 120.7 123.2 98.7 121.7 109.0 73.9 98.6 142.1 01.3 4065.4 Average Hole RQD 840 85% 690 92°� 81 0 75ao 76o b4% 75% 67% 57o 580 6B°d $0 0 19"d 56% 74°� 710 480% 1 76o *USBR boreholes TABLE 7.5: DEVIL CANYON - BOREHOLE ROCK QUALITY DISTRIBUTION Rock P RCENTAGE OF CORE N SPECIF C RQD RA GES Drilled Borehole ( Ft ) 0-254b 25-5040' 50-7590' 75-9006 90-9595 95-100 0 BH-1 738.4 2 6 14 21 13 44 BH-2 653.5 4 4 13 21 14 44 BH-3 383.6 25 18 13 24 13 6 BH-4 488.7 1 2 4 13 16 64 BH-5A 597.9 6 6 10 27 21 30 BH-5B 200.3 9 3 26 36 15 11 BH-7 485.6 11 5 9 30 18 27 DH-1* 114.7 9 23 31 B 8 21 DH-5* 30.7 16 15 22 16 30 1 DH-6* 20.4 91 9 0 0 0 0 DH-8* 148.5 6 10 24 30 8 22 DH-9* 85.0 16 9 13 33 11 18 DH-1O* 120.7 17 18 31 24 10 0 DH-11* 31.2 22 14 12 52 0 0 DH-11A* 28.3 0 0 27 28 28 17 DH-1B* 33.9 14 15 8 30 16 17 DH-11C* 123.2 11 32 30 21 1 5 DH-12* 98.7 5 15 39 20 11 10 DH-12A* 121.7 4 9 10 24 18 35 DH-13* 109.0 71 14 15 0 0 0 DH-13A* 73.9 14 22 37 3 B 16 DH-14A* 98.6 11 9 20 18 20 22 DH-14B* 142.1 9 12 24 16 8 31 DH-14C* 81.3 27 15 35 15 5 3 Total Roc Drilled (feet) 5009.9 * USBR core was relogged from boxes. Several holes have core missing. ABBE 7.6: MM GANY4N RQ CK TEST SUMMARY - MAFIG DIKE$, ANP ARGIEEITE wfgPFesslve unir lensue Borehole Strength }eight Strength Borehole Sample Re ih (ft) (si) ( ef) (,pi) Qihpr* Mafic Dike BH-1 80-43 294,5 13,420 159.8 OH-3 D-3-35Q.4 350.4 9,472 165.7 Argillite BH-2 80-65 247.3 24,4PQ 168.5 6 60-66 273.0 8,p17 168.6 ET = 4.4 x 1Q psi, v = 0.20 80-67 288.7 168.8 3,350 80-64 305.5 81.0-69 343;1 28,467 167.9 80-76 313.1 27y635 168.0 80--77 319.Q 101229 169,0 OH-3 D--3-83.9 83.9 14,5Q9 17Q,4 3,018 11.8 D-3-89.6 89.6 17,487 170,9 ET = x 106 psi 0.19 D-3-127.3 127.3 ED.= 11.3 x 104 psi, v = BH-4 SQ-55 268.95 17,093 169.6 8Q-56 273.5 251213 171.7 80-60 366.Q5 15,047 170.9 BH-5a 0-5A-231.3 231.3 16,227 170.1 3,944 E = 12.7 x 106 psi, v = 0.19 D-5A-269.1 269.1 EO = 12.7 x 106 psi, v = 0.30 D-5A-271.1 271,1 26,840 170.0 HH-56 D-50-149.9 149.9 jQ?722 17Q.7 D-5B-155,2 155.2 168.2 3,329 D-55--1S3.4 183.4 16,227 167.8 BH-7 D-7-174.6 17414 26,840 169.8 D-7-178.1 178.1 21,457 169.2 D-7-319.5 319.5 32,940 160.7 Average (Acres) 20,4Q4 170.1 3,41Q +6f935 SD + 390 SD DH-4 4-46.8 46.0 ED = 11.6 x 1�6 psi, v = 0.Q7 4-50.0 5Q.Q 12791Q PS = 9.4 x 10 6psi, v = 0.16 Ep 10.2 x 106 psi, v = Q.04 0.17 4-50.4 50.4 15,980 F5 = 11.1 x 10 psi, v = 4-51.3 51.3 170.4 Absorption = 0.09, Porosity = 0.24, DH-8 8-89.6 89.6 16,660 171.6 ES = 9.9 x 1Q6 psi, v = 0.22, EpD = 8.27 x 106 psi, v = 0.02 Absorption = g.08, Porosity = 0.21, DH-12 12-44,5 44.5 21,860 169.7 E5 = 8.9 x 10 psi, v = 0.30, E = 9.62 x Absorption 106 psi, v = 0.13 = 0.04, Porosity = 0.12 Average (All Tests) 19,792 +6,533 SD *ED = Dynamic modulus *ET = Tangent modulus at 50% failure stress *ES = Secant modulus *v = Poissons Ratio SD = Standard deviation TABLE 7.7: DEVIL CANYON ROCK TEST SUMMARY -- GRAYWACKE Compressive UnAt lansile Borehole Strength Weight Strength Borehole Sample Depth (ft) (psi) (Ref) { si) Other* BH-1 80-42 281.8 14,589 160.4 1,471 80-44 440.5 28,463 166.8 BQ-45 449.5 28,467 169.8 80-48 510.65 23,453 168.6 ET = 11.6 x 106 psi, v = 0.22 80-73 429.2 27,726 167.8 80-52 571.0 14,556 168.1 2,547 80-53 581.2 167.8 5,071 80-47 505.5 ED = 11.3 x 106 psi, v = 0.22 80-50 536.3 ED = 11.7 x 106 psi, v = 0.26 BH-2 80-62 186.4 4,066 165.7 80-63 195.5 14,655 166.1 psi, v = 0.19 80-71 445.2 13,420 169.2 ET = 9.7 x 106 BH-3 D-3-276.0 276.0 28,396 180.4 ET = 10.9 x 106 Psi, v = 0.23 BH-4 80-54 252.5 29,114 169.6 2,761+ 80-59 351.3 21,960 170.1 80-78 378.05 18,906 169.3 Average (Acres) 20,598 168.8 2,960 +71925 SD +1,515 SD DH-12A 12A-80.1 80.1 28,450 113.5 Es = 9.2 x 106 psi, v = 0.16, 0.15, En 6.98 x Absorption 106 psi, v = 0 08, Porosity 0.24 = = 12A-123.8 123.8 31,260 173.5 Es = 10.2 x 10b psi, v = 0.18, En = 12.09 x 106 psi, v = 0.21, Absorption = 0 12, Porosity = 0.33 12A-143.9 143.9 36,570 171.6 E = 10.3 x 106 psi, v = 0.16, Es = 11.4 x 106 ppsi, v = 0.25, Absorption = 0.07, Porosity = 0.21 Average (All Tests) 22,755 169.5 +8,600 *ED = Dynamic modulus *ET = Tangent modulus at 50% of failure stress *ES = Secant modulus *v = Poissons ratio SD = Standard deviation TABLE 7.8: MATERIAL PROPERTIES - BORROW SITE G Hole/ Trench Number Sample Number De th Lab. Classi- fication Mechanical Anal s s Atterberg Limits Specific GravityWro ram To Gravel San Fine I TTG-1 2 5.0 - SP 65 34 1 2.73 3 16.0 - SP 84 15 1 2.76 4 25.5 - SW 77 20 3 2.72 5 37.0 - SP 55 43 2 2.76 TTG-2 1 2.5 - ML 0 85 15 2.82 2 6.0 - SP 1 98 1 2.78 3 6.5 - GP 62 36 2 2.67 4 6.0 - GP 84 14 2 2.86 5 15.0 - GP 88 11 1 2.87 8 18.0 - GP 80 19 1 2.79 9 24.5 - GP 79 20 1 2.33 AHG-9 4-8 3.0 10.5 SW-SM 18 71 11 2.54 14 45.0 46.5 SW 66 32 2 2.53 3.7 15 50.0 51.5 SM 0 96 4 2.79 6.8 AHG-10 3-5 1.5 6.0 SM 0 64 36 2.63 4 3.0 4.5 30.9 5 4.5 6.0 15.7 6-8 6.0 9.0 SW 0 91 9 2.64 6 6.0 7.5 11.7 7 7.5 8.5 22.9 AHG-11 6-7 6.5 9.5 SW-SM 17 65 18 6 6.5 8.0 16.3 7 6.0 9.5 14.7 8-11 15.0 31.0 5M 34 52 14 8 14.0 16.5 11.2 AHG-12 5-6 4.0 6.0 SW 34 62 2 7-9 6.0 9.5 SW-SM 53 39 8 7 6.0 7.5 6.8 8 7.5 6.5 7.1 AHG-13 4-7 3.5 9.5 SW-SM 7 82 11 7 8.0 9.5 25.5 4 3.5 5.0 24.7 5 5.0 6.5 18.0 6 6.5 8.0 20.2 8 15.0 16.5 ML 0 24 76 9 20.0 21.5 SM 40 35 25 10,12 25.0 32.0 SW-SM 33 56 11 AHG-14 8,9 6.0 9.0 SM 22 64 14 9 7.5 9.0 9.2 10 9.0 10.5 5W-SM 20 72 8 9.9 11 15.0 16.0 SW-SM 41 52 7 12 20.0 21.5 SW-SM 25 68 7 7.0 13 25.0 26.5 CL 4 13 83 49 16 23.5 Em H n Jc REFERENCE, BASE MAP FROM R B M, 1901 - 1"- 200' DEVIL CANYON TOPOGRAPHY. COORDINATES IN FEET, ALASKA STATE PLANE (ZONE 4) LYJ (000 DEVIL CANYON INDEX MAP Q INDEX BLOCK AREA COVERED * SCALE FIGURE NO, REFERENCE O EXPLORATION DAMSITE, TOP OF BEDROCK 1"-500' 1"-500' FIGURE 5,2 FIGURE 7.2 GEOLOGIC MAP 1"-500' FIGURE 7.3 ® TAILRACE AREA 1"-1000' FIGURE 7.14 BORROW SITE G 1"-500' FIGURE I22 ® QUARRY SITE K I"=1000' FIGURE 7.26 LEGEND BORROW/QUARRY SITE LIMITS jf- SCALE AFTER REDUCTION NOTES I. TOPOGRAPHY AND DETAILS SHOWN ON INDIVIDUAL FIGURES. �'"�r�- �� � •� ., �� <f �-"�.-�.r_ c� 0 1000 2000 IFFY SCALE FIGURE 71 N cx LEGEND LITHOLOGY° �.. \ OVERBURDEN, TERRACEDEPOSIT9 AND TALUS W TALU9 AS SHOWN. ARGILLITE AND GRAYWACKE pUTlYASH .• } \ \ TILL — CONTACTS; TS .�f _ ...� __. V� •V 1 - _.'�--_��-�� - - ...-. _.... LIMIT OF OUTCROP TILL CONTOUR LINES' .i TOP OF BEDROCK, CONTOUR INTERVAL 100 FEET, TALUS jo€) 50 FOOT CONTOURS DASHED TILL Av .-."'-'""�_ / /.TAWS\ TILL ���.�-� TOP OF BEDROCK, CONTOUR INTERVAL 20 FEET rs _..:�,' �� .. ---. i I' "' ------ TOPOGRAPHY, CONTOUR INTERVAL 50 FEET //�h .� ��°---TALUS ��._ •-� � � r• `� `� � �; �'`�� � - ._ - �IS� -� -� �-. �.� E I �.. _ �� : , - NO /1A00 �--�� NOTES y I L.SURFICIAL DEPOSITS MODIFIED FROM KACHADOORIAN,(958. 2. . - _ f : k 5M1i,"• 1.5p0 '� '3 4, SHOWN TO LEVATION 1800 FT OUTWASH 3 BEDROCK COOP OF BEDRNOCK TOURS CONTOURS AREINFERRED BASED ON `S �. ,S '%>:�'j�A` f`��>��', i �,,.✓ - GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS, AND Z"_' ARE SUBJECT TO VERIFICATION THROUGH FUTURE ; TILL - �� - �` •\V �V �, r,, DETAILED INVESTIGATIONS. A� V.,. - �13p0 _. TILL i' 1� TERRACE- +. �� DEPOSITS 3� E� 1 \ �t,€I raj%rj�%I /� ' -•" OUT Apo 'TAWS ! }j„ i f 1 �`� `.-\ �Y�•`\���/i- '..TAUS / f i�= 1 TILL 1 I , / � r l ..� ��; °° I TERRACE V ',0 TWA�Hl / f DEPOSITS TILLr l - // } ��'�j'•.... /• - ,.,i� �� %. .,� 6 % ' �£ TiLL , vq '�_ 61 %/•' �- �i ?;fit/� / STREAM a RIVER AL UVIUM B40 -.- - - ,., --� / _ 0 �. /..%.,u, /� � / .,Z f AND STREAM OUTWAS 34 ��3- J T 820 ....�„y _ _l I - _ -� �"� gC •..{'',r� �/ 4� '�'" .�, /� / l /.°'ti ,,fir. ,// , `a:<:,: ,1�� / r -> ._�r j /is a i :TILL ... ,.t-� t..• •\� / ,.. - ' --' .`+, � ,! � /� � S 1. / ��j/� � f 1 •� ' I I' \� ���\• i f V F*I , ' yj,/ J - - y — - FEET TILL 0 200 400 r,.a,���,I�c�s-_--�._.�._.,�_�� �.�� a �'"`"\`�-. ` _-;�— 1 ✓� � :al ��I �� r�'T� �r' /'J - L I7oo�. t ' / / ✓ � ;< t � i� � •' � � .._ its ""Z � � ( � � � % i i % �� IE I � � I f � � l� ,,,. �.- . �--- /J , TIL��"'� E • , J t I l LL 0 I I f / DEVIL CANYON i ; s _ �1 i" v:t' - TADS %' TOP OF BEDROCK I f REFERENCE' BASE MAP DEVIL CANYON FROM TOPOGRAPHY, - I�•200' I / ' AND SURFICIAL GEOLOGIC MAP COORDINATES IN FEET,ALASKA STATE PLANE(20NE 4) FIGURE 72 i�i Na,2eMOW) ---- 7 m3'a4,t1BD _-- REFERENCE, BASE MAP FROM R BM, 1961 - 1"-200' DEVIL CANYON TOPOGRAPHY. COORDINATES IN FEET,ALASKA STATE PLANE (ZONE 4) GEOLOGIC MAP LEGEND LITHOLOGY: OVERBURDEN, UNDIFFERENTIATED ARGILLITE AND GRAYWACKE OUTCROP FELSIC DIKE, WIDTH SHOWN WHERE GREATER THAN 10 FEET K MAFIC DIKE, WIDTH SHOWN WHERE GREATER U-2 THAN 10 FEET CONTACTS: --.... 11 -- LIMIT OF OUTCROP STRUCTURE: Imo�? SHEAR, WIDTH SHOWN WHERE GREATER THAN i,Sh'li4'W I 10 FEET, VERTICAL UNLESS DIP SHOWN SHEAR, WIDTH LESS THAN 10 FEET, INCLINED, VERTICAL, EXTENT WHERE KNOWN F== FRACTURE ZONE, WIDTH SHOWN WHERE GREATER THAN 10 FEET, VERTICAL UNLESS -hh• DIP SHOWN 7�[I ( SIFTS, I NCLI EI I,O PE i INCLINED, VERTICAL 50.J,/ BEDDING /FOLIATION, INCLINED, VERTICAL OTHER: DC-1 GEOLOGIC SECTION LOCATION 4DCJ-1 JOINT STATION GE) GEOLOGIC FEATURE DESCRIBED IN SECTION 7.1 MI MAFIC DIKE DESCRIBED IN SECTION 7.1 F € FELSIC DIKE DESCRIBED IN SECTION 7.1 NOTES 1. GEOLOGiC SECTIONS SHOWN ON FIGURES 7.4 THROUGH 7.10. 2, JOINT PLOTS SHOWN ON FIGURE 7.€3 3. ADDITIONAL GEOLOGIC DATA FROM USER, 1960. 4, CONTOUR INTERVAL 50 FEET, 5. EXPLORATION LOGS AND SEISMIC LINE SECTIONS IN APPENDICES C,E. H, AND I. 6. EXTENT OF SHEARS, FRACTURE ZONES AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS, AND ARE SUBJECT TO VERIFICATtDN THROUGH FUTURE DETAILED INVESTIGATIONS. 0 200 400 FEET SCALE FIGURE 7.3 R a r 1500 1 500 088°� AZIMUTH a 268' OF SECTION LOOKING SOUTH 11,150 FPS DC-4 I APPARENT�a DIP LEGEND LtTHOLOGY: OVERBURDEN, UN DIFFERENTIATED ARGILLITE AND GRAYWACKE INFERRED ORIENTATION OF BEDDING/ FOLIATION, APPARENT DIP WHERE NOTED FELSIC DIKE, WIDTH SHOWN WHERE GREATER THAN 10 FEET MAFIC D€KE,WIDTH SHOWN WHERE xx GREATER THAN 10 FEET CONTACTS: APPROXIMATE TOP OF ROCK - LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE= "I!SHEAR, WIDTH SHOWN WHERE GREATER � THAN iO FEET FRACTURE ZONE WIDTH SHOWN WHERE GREATER THAN 10 FEET GEOPHYSICAL SURVEYS: QSW-15 INTERSECTION WITH SEISMIC REFRACTION LINE S W - IB 1978, SHANNON B WILSON 1500 SL 80-13 1960, WOODWARD-CLYDE CONSULTANTS SLOI-22 1961,WOODWARD-CLYDE CONSULTANTS ......•••• SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCffY IN FEET PER SECOND FPS BOREHOLES: 8H-I LITHOLOGY F_FRACTURE ZONE 5= SHEAR OH-1 USBR DIAMOND CORE BORING BH- 1 AAI DIAMOND CORE BORING AH -G€ AAI AUGER HOLE 1000 OTHER: DC-1 I INTERSECTION WITH GEOLOGIC W SECTION DC -I GF I GEOLOGIC FEATURE DESCRIBED IN SECTION 7.1. MI MAFIC DIKE DESCRIBED IN SECTION 7.1. F I FELSIC DIKE DESCRIBED IN SECTION 7.1. NOTES L SECTION LOCATION SHOWN ON FIGURE T.3. 2. VERTICAL B HORIZONTAL SCALES EQUAL. 3. SURFACE PROFILE FROM I°=200` TOPOGRAPHY, R 8 M,196I. 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES C,E,H AND I. 500 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. O 100 200 FEET SCALE DEVIL CANYON GEOLOGIC SECTION DC- I SHEET i OF 2 FIGURE 7.4 ����� LEGEND LITHOLOGY OVERSURDEN, UNDIFFERENTIATED ARGILLITE AND GRAYWACKE INFERRED ORIENTATION OF BEDDING/ FOLIATION, APPARENT DIP WHERE NOTED AZIMUTH x__ r;'�:,�;-I FELSIC DIKE, WIDTH SHOWN WHERE OF SECTION L_:-YL-J GREATER THAN 10 FEET LOOKING SOUTH MAFIC DIKE,WIDTH SHOWN WHERE RIVER FLOW —® �,x GREATER THAN 10 FEET CONTACTS: ----- APPROXIMATE TOP OF ROCK - L€THOLOGIC, DASHED WHERE INFERRED STRUCTURE: SHEAR, WIDTH SHOWN WHERE GREATER THAN 10 FEET \\ FRACTURE ZONE, WIDTH SHOWN WHERE GREATER THAN €0 FEET GEOPHYSICAL SURVEYS 1 q SW_15 INTERSECTION WITH SEISMIC REFRACTION LINE SW - €5 €978, SHANNON 8 W ILSON 1500 CREST OF DAM 1500 SL 80-€3 1980, WOODWARD-CLYDE CONSULTANTS EL.1463' SLBI-22 1961,WOODWARD-CLYDE CONSULTANTS loo %R SEISMIC VELOCITY CHANGE �g090 0 % ROD 12FPS SEISMIC VELOCITY IN FEET PER SECOND s� loo sO o EL 13OREHOLES ° BH I 6 -892 `r C0 }CORE MI59tNG JOyu/� Rg M7ss/ LlTHOLO GY F FRACTURE _ >Be ZONE U is DH-€IC - 766 S= SHEAR r DH-I USSR DIAMOND CORE BORING SU5ITNA RIVER p� BH- 1 AAI DIAMOND CORE BORING ao CREST OF (RIVER FLOW�) DOWNSTREAM COFFEDAM '_1 AH -Gf AAI AUGER HOLE 1 a 1000 EL.920' 1000 OTHER: m WATER DEPTH OC-3 DH-12 DC-1 I INTERSECTION WITH GEOLOGIC DC 5 W w UNCERTAIN PROJECTED WATER DEPTH SECTION DC_I 15'N DH-11C UNCERTAIN APPARENT GF I GEOLOGIC FEATURE DESCRIBED IN DIP SECTION 7,1. MI MAFIC DIKE DESCRIBED IN SECTION 7.1. ~ _ _ APPARENT APPARENTDIP Ifl FI FELSIC DIKE DESCRIBED IN SECTION 7.1. TREND � y �.J^ 340° DIP I BOTTOM F 1 . i PROJECTED BOTTOM 1 NOTES TREND �30'S PROJECTED 1 GF8I. 345° BO'S - GF9 J�-TREND 345° I 1 INFERRED SHEAR—�', INFERRED I. SECTION LOCATION SHOWN ON FIGURE 7.3. 1 TREND 3401 SHEAR 2. VERTICAL d HORIZONTAL SCALES EOUAL. F7 TREND 335° �. TREND GF5 * 3. SURFACE PROFILE FROM I"=200' M 4 TREND 20°TOPOGRAPHY, H f?t M,1981, GF4 PROJECTED { 4, EXPLORATION LOGS AND SEISMIC LINE SEGnDNS GF 2 M 3 !30'AT 140 +, M 2 TREND 320• ROJECr8O' AT 170° ° � 40°f GF6 SHOWN IN APPENOICIES C,E,H ANDS. [ TREND 350 TREND 355° 500 � � I I 500 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON PROJECTED GF 3 GEOLOGIC MAPPING AND SUBSURFACE 115' AT 175EXPLORATIONS,ANDARE SUBJECT TO VERIFICATION M) THROUGH FUTURE DETAILED INvES11GATIONS, PROJECTED 100 AT 175° DEVIL CANYON GEOLOGIC SECTION DC-1 SHEET 2OF 2 0 €00 200 FEET SCALE FIGURE 7.4 �C��� 1500 000 500 090°-® AZ I MUTH OF 270' OF SECTION LOOKING SOUTH DEVIL CANYON GEOLOGIC SECTION DC-2 DC-3 I eti. , € BOTTOM " J PROJECTEDI !it 205'N !II II� F 7 GF4 li PROJECTED 320, TREND 345° Y f TREND 325° TIED 335° LEGEND LITHOLOGY: OVER BURDE N, UNDIFFERENTIATED ARGILLITE AND GRAYWACKE -� INFERRED ORIENTATION OF BEDDING/ FOLIATION, APPARENT DIP WHERE NOTED FELS€C DIKE, WIDTH SHOWN WHERE GREATER THAN 10 FEET MAFIC DIKE WIDTH SHOWN WHERE GREATER THAN 10 FEET CONTACTS ----- APPROXIMATE TOP OF ROCK ^----- LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: s��ifa5, SHEAR1 W107H SHOWN WHERE GREATER UIJ THAN ID FEET �- FRACTURE ZONE, WIDTH SHOWN WHERE GREATER THAN €0 FEET GEOPHYSICAL SURVEYS QSW-15 INTERSECTION WITH SEISMIC REFRACTION LINE SW-15 1978,SHANNON aWILSON St BO-13 I9BO,WOODWARD-CLYDE CONSULTANTS SLBI-22 1981,WOODWARD-CLYDE CONSULTANTS •.••••••.• SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND FPS BOREHOLES: BH-I LITHOLOGY F= FRACTURE ZONE S= SHEAR 1500 DH-I USER DIAMOND CORE BORING BH- I AAI DIAMOND CORE BORING AH -GI AAI AUGER HOLE OTHER DC-1 W I INTERSECTION WITH GEOLOGIC SECTION DC -I GFI GEOLOGIC FEATURE DESCRIBED IN SECTION 7.1. MI MAFIC DIKE DESCRIBED IN SECTION 7.1. FI FELSIC DIKE DESCRIBED IN SECTION 7.1. NOTES I. SECTION LOCATION SHOWN ON FIGURE 7.3. 1000 2. VERTICAL a HORIZONTAL SCALES EQUAL. 3, SURFACE PROFILE FROM I°=200' TOPOGRAPHY, RaM,198L 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES C,E,H AND I. 5, EXTENT OF SHEARS, FRACTURE ZONES,ANO ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. 500 0 €00 200 FEET SCALE FIGURE 7.5 LEGEND LITHOLOGY : OVERBURDEN, UNDIFFERENTIATED ARGILLITF AND GRAYWACKE INFERRED ORIENTATION OF BEDDING/ FOLIATION, APPARENT DIP WHERE NOTED FELSIC DIKE, WIDTH SHOWN WHERE GREATER THAN 10 FEET — — MAFIC DIXE,W€DTH SHOWN WHERE ,.xx„j GREATER THAN 10 FEET CONTACTS: --- APPROXIMATE TOP OF ROCK - LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: F. SHEAR, WIDTH SHOWN WHERE GREATER Si'L!; S'yI THAN 10 FEET FRACTURE ZONE, WIDTH SHOWN WHERE GREATER THAN 10 FEET GEOPHYSICAL SURVEYS: �SW_15 INTERSECTION WITH SEISMIC REFRACTION LINE SW -,15 1978, SHANNON Ei WILSON SL80-13 1980,WOODWARD-CLYDE CONSULTANTS SLBI-22 19BI,WODDWARD-CLYDE CONSULTANTS .1........ SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND 1500 h 1000 F 500 BOREHOLES; BH-I LITHDLOGY F= FRACTURE ZONE S= SHEAR DH-I USBRDIAMOND CORE BORING BH-I AAI DIAMOND CORE BORING AH -GI AAI AUGER HOLE OTHER DC•I I INTERSECTION WITH GEOLOGIC W SECTION DC-1 GF€ GEOLOGIC FEATURE DESCRIBED IN SECTION 7.1, MI MAFIC DIKE DESCRIBED IN SECTION T.I. FI FELSIC DIKE DESCRIBED IN SECTION T.I, NOTES I. SECTION LOCATION SHOWN ON FIGURE 7.3. 2. VERTICAL 8€ HORIZONTAL SCALES EQUAL. 3. SURFACE PROFILE FROM I"=200' TOPOGRAPHY, RE, M, 1981. 4, EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES C,E,H AND 2. 5. EXTENT OF SHEARS, FRACTURE ZONES,AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. 1L10 °!.� C O0 YE4p3 O"A— AZIMUTH --im-I80, OF SECTION LOOKING UPSTREAM DEVIL CANYON GEOLOGIC SECTION DC-3 P00 0 63A2 \d BH-3 PROJECTED St 60-15 3V E I e €rr4T nr cAnni r nnu ri 1479' 0 100 2DO FEET SCALE SL 80-I2 PROJECTED 60 E 16,000 FPS FPS FIGURE 7.6 1 1500 { 1000 AZIMUTH O�� OF SECTION _180 LOOKING UPSTREAM 1500 LEGEND LITHOLOGY: OVERBURDEN,UNDIFFERENTIATED ARGILLITE AND GRAYWACKE INFERRED ORIENTATION OF BEDDING/ FOLIATION, APPARENT DIP WHERE NOTED FELSIC DIKE, WIDTH SHOWN WHERE x GREATER THAN 10 FEET MAFIC DIKE WIDTH SHOWN WHERE GREATER THAN 10 FEET CONTACTS: --^---- APPROXIMATE TOP OF ROCK - LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: SHEAR,WIDTH SHOWN WHERE GREATER THAN 10 FEET FRACTURE ZONE, WIDTH SHOWN WHERE GREATER THAN 10 FEET GEOPHYSICAL SURVEYS: Q SW-15 INTERSECTION WITH SEISMIC REFRACTION LINE SW-15 1978, SHANNON & WILSON SL80-13 1980,WOODWARD-CLYDE CONSULTANTS SL8I-22 1961, WOODWARD -CLYDE CONSULTANTS ..........SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND FPS BOREHOLES; BH-I 1500 LITHOLOGY F= FRACTURE ZONE 5= SHEAR CH -I USBRDIAMOND CORE BORING BH- I AAI DIAMOND CORE BORING AN -GI AAI AUGER HOLE OTHER: DC -I I INTERSECTION WITH GEOLOGIC W SECTION OC-I GF I GEOLOGIC FEATURE DESCRIBED IN SECTION T.I. Ml MAF1C DIKE DESCRIBED IN SECTION T.I. FI FELSIC DIKE DESCRIBED IN SECTION T.I. 1000 NOTES I. SECTION LOCATION SHOWN ON FIGURE T,3. 2, VERTICAL e. HORIZONTAL SCALES EQUAL. 3. SURFACE PROFILE FROM #"=200' TOPOGRAPHY, RBM,1961, 4, EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES C,E,H AND Z. 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. BOTTOM D 500 J 0 100 200 FEET 900 BOTTOM 70'W SCALE DEVIL CANYON GEOLOGIC SECTION DC-4 �AC�RE� FIGURE 7.7 351° `__ AZIMUTH I 7I' OF SECTION LOOKING UPSTREAM s ppa 0 O;5,p j 1500 H W W a 0 a a r w 1000 LEGEND LITHOLOGY: OVER BURDEN, UNDIFFERENTIATED LAARGILLITE AND GRAYWACKE INFERRED ORIENTATION OF BEDDING/ FOLIATION, APPARENT DIP WHERE NOTED r"';`• FELS€C DIKE, WIDTH SHOWN WHERE z GREATER THAN 10 FEET MAFIC DIKE,WIDTH SHOWN WHERE GREATER THAN 10 FEET CONTACTS ----- APPROXIMATE TOP OF ROCK - LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: SHEAR, WIDTH SHOWN WHERE GREATER 5'II�P,;J THAN 10 FEET FRACTURE ZONE, WIDTH SHOWN WHERE 11 GREATER THAN 10 FEET GEOPHYSICAL SURVEYS= QSW-15 INTERSECTION WITH SEISMIC REFRACTION LINE SW-15 1978,SHANNON 9 WILSON SL 80-13 1980, WOODWARD-CLYDE CONSULTANTS SLOI-22 196I,WOODWARO-CLYDE CONSULTANTS .......... SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND FPS BOREHOLES: OH-1 1500 LITHOLOGY F- FRACTURE ZONE 5= SHEAR DH-I USBR DIAMOND CORE BORING B H - I AAf DIAMOND CORE BORING AH -GI AAI AUGER HOLE OTHER: DC-1 I INTERSECTION WITH GEOLOGIC W SECTION DC-1 GFI GEOLOGIC FEATURE DESCRIBED IN SECTION 7.1. MI MAFIC DIKE DESCRIBED IN SECTION TI. $000 FI FELSIC DIKE DESCRIBED IN SECTION 7.1. NOTES L SECTION LOCATION SHOWN ON FIGURE 7.3. 2. VERTICAL a HORIZONTAL SCALES EQUAL, 3. SURFACE PROFILE FROM I°=200' TOPOGRAPHY, R5M,1981. 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES C,E,H AND 1. 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. 600 e- 5D0 O 100 200 FEET SCALE DEVIL CANYON GEOLOGIC SECTION DC-5 FIGURE 7.8 1500 h W a� O h y m w 1000 500 LEGEND LITHOLOGY : OVERBURDEN, UNDIFFERENTIATED ARGILLITE AND GRAYWACKE INFERRED ORIENTATION OF 5EDDING/ FOLIATION, APPARENT DIP WHERE NOTED AZIMUTH 0°� �i80° OF SECTION r"�'%� FELSIC DIKE, WIDTH SHOWN WHERE �,'� _J GREATER THAN 10 FEET LOOKING UPSTREAM SHOWN WHERE IKTHAN GREATER 10 DEVIL CANYON GEOLOGIC SECTION DC-6 CONTACTS ----- APPROXIMATE TOP OF RDCK -- LITHOLOGIC. DASHED WHERE INFERRED STRUCTURE: f��,�., SHEAR,WIDTH SHOWN WHERE GREATER �K!J THAN 10 FEET EREFRACTURE ZONE, WIDTH SHOWN WHERE GREATER THAN 10 FEET GEOPHYSICAL SURVEYS � I SW-15 INTERSECTION WITH SEISMIC REFRACTION LINE IBOO SW-€5 1978, SHANNON aWILSON SL 90-13 1980, WOODWARD-CLYDE CONSULTANTS SLOI.22 1981,WOODWARD-CLYDE CONSULTANTS •^^^••• SEISMIC VELOCITY CHANGE 12,ODO SEISMIC VELOCITY IN FEET PER SECOND FPS BOREHOLES: BH-1 LITHOLOGY F= FRACTURE ZONE S= SHEAR OH -I USBR DIAMOND CORE BORING BH- I AAI DIAMOND CORE BORING 1000 AH -GI AA1 AUGER HOLE OTHER: DC -I I INTERSECTION WITH GEOLOGIC �l' SECTION DC -I GF I GEOLOGIC FEATURE DESCRIBED IN SECTION 7.1. MI MAFIC DIKE DESCRIBED 1N SECTIDN 7.1. F I FELSIC DIKE DESCRIBED IN SECTION 7.1. NOTES I. SECTION LOCATION SHOWN ON FIGURE 7.3. 2. VERTICAL a HORIZONTAL SCALES EQUAL, 3. SURFACE PROFILE FROM I°=200' TOPOGRAPHY, R5 M, 1981, 4. EXPLORATION LOGS AMC SEISMIC LINE SECTIONS BOO SHOWN IN APPENDtC;ES C,E,H AND 2. 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORAT3ONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS, 0 100 200 FEET SCALE FIGURE 7.9 ����� 1500 I DEPTH OF OVERBURDEN NOT KNOWN APPARENT DIP 500 e SUSITNA RIVER (LOOKING UPSTREAM) WATER DEPTH UNCERTAIN MUTH 088° OF SIECTION' 268° LOOKING SOUTH SW-168 PROJECTED 185' N 11,150 FPS zl J� S g _ I IORROW SITE G (ALLUVIAL FAN) SW-16 SW -16 PROJECTED 35' S ®EVIL CANYON GEOLOGIC SECTION DC-7 SHEET I OF 3 LEGEND L ITH OLOGY : OVERBU RDEN, UNDIFFERENTIATED ARGILLITE AND GRAYWACKE INFERRED ORIENTATION OF BEDDING/ FOLIATION, APPARENT DP WHERE NOTED FELSIC DIKE, WIDTH SHOWN WHERE L1_4 =':j GREATER THAN IO FEET F-77.=-��� MAFIC DIKE,WIDTH SHOWN WHERE 4„A-�� GREATER THAN IO FEET CONTACTS: ----- APPROXIMATE TOP OF ROCK - LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: SHEAR,WIDTH SHOWN WHERE GREATER THAN 10 FEET FRACTURE ZONE, WIDTH SHOWN WHERE Lim GREATER THAN IO FEET GEOPHYSICAL SURVEYS. TSW-15 INTERSECTION WITH SEISMIC REFRACTION LINE SW - 15 1978, SHANNON 8 W ILSON SL 80-13 19B0,WOODWARD-CLYDE CONSULTANTS SL81-22 1981, WOODWARD-CLYDE CONSULTANTS ......•••• SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND FPS 1500 BOREHOLES: BH-1 LITHOLOGY F= FRACTURE ZONE S= SHEAR DH-1 USER DIAMOND CORE BORING BH-I AAI DIAMOND CORE BORING AH -GI AA I AUGER HOLE OTHER; DC-1 I INTERSECTION WITH GEOLOGIC �i' SECTION DC -I GF I GEOLOGIC FEATURE DESCRIBED IN SECTION 7.1. ME MAFIC DIKE DESCRIBED IN SECTION 7,1, 1000 F I FELSIC DIKE DESCRIBED IN SECTION 7.1. NOTES I. SECTION LOCATION SHOWN ON FIGURE 7,3, 2. VERTICAL B HORIZONTAL SCALES EQUAL. 3, SURFACE PROFILE FROM I"=2OD' TOPOGRAPHY, RBM,1981. 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES C,E,H AND I. 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. ' 500 O 100 200 FEET SCALE FIGURE 7.10 1000 r w LL F1000 a Id 600 L 088°<a- AZIMUTH __s-268° OF SECTION LOOKING SOUTH RIVER FLOW—rg- SL 80-I3 .Q J DH-10 L) JECTED DH-I PROJECTED PRO ~ 1B0'N PROJECTED €10'N m 20's DH-9 SL 80-12 Pam, DC-3I Ii0' N THRUST BLOCK DC-4 AREA OF OPEN' JOINTS 1� S F BOl (DIAGRAMMATIC) BOTTOM BOTTOM PRC TREND 325° PROJECTED 50 w PEN' 6O N PROJECTED DINTS 80'N F. BOTTOMOPEN JOINT IOA PROJECTEDTREND 65 BORROW 9SITEE G DIP ,15'N MAFIC DIKE . { (ALLUVIAL FAN) SW-IGA APPARENT SW-6 PROJECTED DIP j 1 PROD. 100'S 35'S DC-6 Q 1 7 !!! GF6 PROJECTED PROJECTED APPARENT 175'S 15' S TREND 320' TREND 31B5 FPDIP ' S +'"S .y I 335— DIVERSION TUNNEL 11,150 FPS TREND 325.- TREND 0° PROIIECTED ' t )PRO SCTED I:[ 200 5 GF 3 l TREND� PLC\ GF 4 L' 330° J PROJECTED I- 50 AT 170° TREND 350° DEVIL CANYON GEOLOGIC SECTION DC-7 SHEET 2 OF 3 LEGEND LITHOLOGY: OVER BUR DEN, UNDIFFERENTIATED ARGILLITE AND GRAYWACKE INFERRED ORIENTAT3ON OF BECDWG/ FOLIATION, APPARENT DIP WHERE NOTED -' FELSIC DIKE, WIDTH SHOWN WHERE x=;J GREATER THAN 10 FEET MAFIC DIKE,WIDTH SHOWN WHERE "-'" =" GREATER THAN 10 FEET CONTACTS: ----- APPROXIMATE 70P OF ROCK - LITHOLOGIC, DASHED WHERE INFERRED STRUCTURE: F, `lye SHEAR, WIDTH SHOWN WHERE GREATER Li;L''SJ THAN 10 FEET LFRACTURE ZONE, WIDTH SHOWN WHERE � GREATER THAN 10 FEET GEOPHYSICAL SURVEYS: 4SW-15 INTERSECTION WITH SEISMIC REFRACTION LINE SW-15 1978,SHANNON B WILSON SI-80-13 $980, WOODWARD -CLYDE CONSULTANTS SLOI-22 1981,WOODWARD-CLYDE CONSULTANTS ... "..... SEISMIC VELOCITY CHANGE 12,0PS 00 FSEISMIC VELOCITY IN FEET PER SECOND 1500 BOREHOLES OH -I LITHOLOGY— F= FRACTURE ZONE S= SHEAR DH-I USBR DIAMOND CORE BORING BH-I AAI DIAMOND CORE BORING AH -GI AAI AUGER HOLE OTHER: DC -I W I INTERSECTION WITH GEOLOGIC SECTION DC -I GFI GEOLOGIC FEATURE DESCRIBED IN SECTION 7.1. MI MAFIC DIKE DESCRIBED IN SECTION 7.1. 1000 F I FELSIC DIKE DESCRIBED IN SECTION 7.1. 500 NOTES I. SECTION LOCATION SHOWN ON FIGURE 7.3, 2. VERTICAL a HORIZONTAL SCALES EQUAL, 3, SURFACE PROFILE FROM 0=200' TOPOGRAPHY, RB M; I%B 1. 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES C,E,H AND I. 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. 0 100 900 FEET SCALE FIGURE 7.10 A % RQD 100 50 0 L J E L. -1497 - 373 OH-B 1500 500 LEGEND LITHOLOGY OVERBURDEN, UNDIFFERENTIATED ARGILLITE AND GRAYWACKE - - INFERRED ORIENTATION OF BEDDING/ 068" *_ AZIMUTH 268e I `%� FOLIATION, APPARENT DIP WHERE NOTEO OF SECTION x�FELSIC PIKE, WIDTH SHOWN WHERE x GREATER THAN 10 FEET LOOKING SOUTH MAFIC UIKE,WIOTH SHOWN WHERE RIVER FLOW-0- ri GREATER THAN 10 FEET CONTACTS: ----"' APPROXIMATE TOP OF ROCK �--- LITHOLOGIC, DASHED WHERE INFERRED DEVIL CANYON GEOLOGIC SECTION DC-7 SHEET 3 OF 3 STRUCTURE: 1 ,ii,y1 SHEAR, WIDTH SHOWN WHERE GREATER -; THAN 10 FEET FRACTURE Li\ GREATER THANZONEO FIEET DTH SHOWN WHERE GEOPHYSICAL SURVEYS QSW-15 INTERSECTION WITH SEISMIC REFRACTION LINE SW - 15 1978, SHANNON a WILSON SL 80-13 1990, WOODWARD-CLYDE CONSULTANTS SLBI-22 1961, WOODWARD- CLYDE CONSULTANTS SEISMIC VELOCITY CHANGE 12,000 SEISMIC VELOCITY IN FEET PER SECOND FPS 1500 BDREHOLES LITHOLOGY F= FRACTURE ZONE S= SHEAR DH-I USBR DIAMOND CORE BORING BH' I AAI DIAMOND CORE BORING AH -GI AAI AUGER HOLE OTHER: DC -I I INTERSECTION WITH GEOLOGIC W SECTION DC -I GFI GEOLOGIC FEATURE DESCRIBED IN SECTION T,I. MI MAFIC DIKE DESCRIBED IN SECTION 7,1, 1000 F€ FELSIC DIKE DESCRIBED IN SECTION T.I. 500 NOTES I. SECTION LOCATION SHOWN ON FIGURE 7.3. 2. VERTICAL a HORIZONTAL SCALES EQUAL. 3. SURFACE PROFILE FROM 1"=200' TOPOGRAPHY, RBM,,1981. 4, EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDICIES C,E,H AND I. 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. 0 - 100 200 FEET SCALE FIGURE 7.10 �C�ES ACROSS RIVER FROM CHEECHAKO CREEK RIVER LEVEL -NORTH BANK NOTES, I. GRADED BEDS OF ARGILLITE/GRAYWACKE, 2. STRATIGRAPHIC TOP TO LOWER LEFT. DEVIL CANYON TYPICAL ARGILLITE/GRAYWACKE FIGURE 7.11 -- M3 -- ... WEST EAST RIVER -dl--- FLOW NOTES: I. DIKES M I AND M 3 DESCRIBED IN SECTION 7.1. 2. GEOLOGIC FEATURES GF 3,GF4,AND GF5 DESCRIBED IN SECTION 7.1. DEVIL CANYON AERIAL VIEW OF SITE FIGURE 7.12 RCS 3 SET �5 12 iz SAE 3 5 E r/L SET I SET L/ € III 73 lJ I \ N \ JOINT STATION DCJ- I \ DCJ-1 I If � SET E 1 •�\ L] 7 E SET 3 W �I 1 SET SET X 3 i N JOINT STATION DCJ-2 N =100 E APPROXIMATE DAM CENTERLINE US/7-NA R/VFR DCJ•2 DCJ-3 SET I� I Cp � SET I SET I I M n 1 SET 2 10 7 5 n € �J SET I N COMPOSITE JOINT PLOT SOUTH BANK N=479 W COMPOSITE JOINT PLOT NORTH BANK N = 714 DCJ-4 N JOINT STATION DCJ-4 ��•� N =100 NOTES I. CONTOURS ARE PERCENT OF JOINTS PER 1% OF AREA. CONTOURS SHOWN- 1,3,5,7,10,15, a 20%. 2. N EQUALS NUMBER OF DATA POINTS, 3. COMPOSITE PLOTS INCORPORATE ALL JOINT DATA, JOINT STATION PLOTS CONTAIN DATA FROM SPECIFIC JOINT STATIONS. 4. FOR JOINT PLOTTING METHOD SEE FIGURE 6.12 N DEVIL CANYON JOINT STATION DGJ-3 JOINT PLOTS N = 100 FIGURE 7.13 W Z O } O z a C9 o Ki o O W N O J Y W k' W W Q > w CU � Y j� UP m W� w V o c Z� H dl V Q U p z 0 1!. Z JL+-w¢o w Q = a W O oZ w0 o wco wm- -�z o a� wwo C] x x F— W :: z W o w J o Vl U LL I f Z N w Y CU a 3 a CD 0 z a w H J J O cr a M n "K01) to tO LO cD n It OD 111l f 0 to O w N w W LL LO �7����� O r ✓.a✓ o w LL Ld ✓ -' / o u' o Q z Z U ® C7 Jt Z r Q U LLJ 0 J 7 Ld 0 U Ld Q Q N co f � LO co ,,....�.•' s..d .....�. m,.�....�_.. _,...W. COMPRESSION TEST FAILURE ALONG HEALED DISCONTINUITY TYPICAL TENSILE STRENGTH TEST DEVIL CANYON ROCK TESTS COMPRESSION TEST FAILURE THROUGH INTACT ROCK TYPICAL COMPRESSION TEST WITH STRESS -STRAIN READINGS FIGURE 7.15 LEGEND 24 21 1B 9 6 ROCK TYPE: GRAYWACKE FAILURE STRESS: 23,453 psi ET50'II.6XIO6psi, v=0.22 ESd IL6xIO6 psi, v=0.22 3 BOREHOLE: BH- I , SAMPLE No.: RO-4B DEPTH = 510.65 FEET L/D -2.57 Y = 168.6 pcf 0.06 0.03 0 0.03 0.06 0.09 0,12 0.15 0,18 0.21 {+) STRAIN (%) (-) 24 21 15 J Q 12 is 9 / d ROCK TYPE: ARGILLITE 6 FAILURE STRESS: 17,487 psi ET50=IL8x106psi ER=11.8x106psi 3 BOREHOLE! BH-3, SAMPLE No.: D-3-89.6 DEPTH F 89.6 FEET L/D-2.58 y =170.3 pcf O 0.03 0.06 0.09 0.12 0.15 STRAIN ('Q (-) O AXIAL STRAIN Z�l VOLUMETRIC STRAIN E DIAMETRIC STRAIN ES SECANT MODULUS ET5O TANGENT MODULUS AT 50% FAILURE STRESS NOTE SAMPLE DIAMETER =1.77" a ROCK TYPE: ARGILLITE 6 FAILURE STRESS: 8,017 psi ET50=4.4 x106 psis, v=0.20 E5=4.4xIO6psi, u=o.20 3 BOREHOLE: 8H-2, SAMPLE No.:80-66 DEPTH= 273.0 FEET L/D=2.61 y=168.6pcf 0.06 0.03 0 0.03 0.06 0.09 OA2 (+) STRAIN 06) 1_) 15 12 9 9 ROCK TYPE: GRAYWACKE 6 TYPE GRAYWACKE ROCK TYPE ARGILLITE FAILURE STRESS: 28,398-pei ET50'10.9x106psi, FAILURE STRESS: 13,420 psi 6 FAILURE STRESS: 16,22T psi v=0.23 '8.6x106psi., v=0.17 V ET508t2,7xIO6psi, v=0,19 ES=j0.4x106psi, v=o.23 .7xI06psi, v=0.19 ES- iz.7xloG psi, v=0.f9 3 80REHOLE: BH-3, SAMPLE No.: D-3-276.0 OLE: BH-2, SAMPLE W. 80-713 BOREHOLE: BH-SA, SAMPLE No.= D-5A-231.3 DEPTH • 276.0 FEET = 445.2 FEET DEPTH - 231.3 FEET L/D2.59 y*1B0.4pcf 2.50 y=169.2 pc3 L/D=2.64 Y"170.1 pet O.C9 0.06 0.03 0 0.03 0.06 0.09 0.12 0.15 0.18 0.21 0,24 0,06 0.03 O 0.03 0.06 0.09 0.12 0.15 0.18 0.06 0.06 0.09 0.12 0.03 0 0.03 (+) STRAIN (W (-) 1+) STRAIN {%} (_) (q) STRAIN DEVIL CANYON - STATIC ELASTIC PROPERTIES FOR ARGILLITE AND GRAYWACKE FIGURE 7.I6 cl LEGEND �p PEAK FRICT€ON ANGLE % RESIDUAL FRICTION ANGLE 180 ISO 190 W PEAK VALUES A RESIDUAL VALUES CD VERTICAL DISPLACEMENT 160 Igo 160 d Q ..,..Q :.�„ A NORMAL LOAD=75PSI I40© oil [, 140 El Q Q Q NORMAL LOAD=150 PSI Q:.-p [] �.._ 140 .. C APPARENT COHESION 1 FRICTION ANGLE ENVELOPE 9 120�❑ Q_.:. o f20 Qa`'� d 0 120..d a o I00 '• z 100 e A,cc Z a 100 A o a g NOTES < Ui 90 ya a N H0 &&& A s BOE tI. MAXIMUM SHEAR BOX DISPLACEMENT°0.3 iNCHES • ADA Ae A A A Q A la w 2. STRAIN RATE - 0.039 IN. /MIN. w �A Q 40 g a N 40 40 000000 O a. N2 ��00O0�00000 �O 20 fl 00� 0.05 a s U � ¢ 20 20 0 G (D � � � (D 0 0 0.05 0.10 0.15 _��Q1-_ 0.2D 0.25 0.30 W 0,35 0 0 0.05 0.10 0.15 0.20 0.25 0.30 0,35 or 0 0106 0.10 0.15 0.20 0.25 J 0.30 0.35 _ SHEAR DISPLACEMENT IN INCHES SHEAR DISPLACEMENT IN INCHES SHEAR DISPLACEMENT IN INCHES €DO ROCK TYPE: ARGILLITE BOREHOLE: 0H-2 SAMPLE: 00-68 00 DEPTH: 305,5' SAMPLE AREA: 1.975 SO. IN. � �p=27. ` ,n 60 , N M 40 �R=23° w a W 20 0 0 20 40 60 80 100 t20 140 ISO NORMAL STRESS (PSI) ARGILLITE, NATURAL JOINT, SLICK, CHLORITIZED, DRY 100 - ROCK TYPE: ARGILLITE BOREHOLE: SH-5a SAMPLE: D-5u-22L5 80 DEPTH: 221.5' SAMPLE AREA: 2.468 S0. IN. in a �P • 3i° N 60 N W ¢ N 40 C=6 PSI � _< w 20 p 0 20 40 60 80 100 120 140 160 NORMAL STRESS (PSII POLISHED ARGILLITE ON MORTAR, BOND BROKEN, DRY DEVIL CANYON DIRECT SHEAR TESTS SHEET I OF 3 100 ROCK TYPE: ARGILI.ITE BOREHOLE: 8H-5u SAMPLE: 0-5a-221.5 DEPTH: 221.5' 80 SAMPLE AREA: 2.468 SO. IN. H a N 60 W N�..._ (�P°2€.5° a 40 w H OW19.5° 20 0 ! i 0 20 40 60 80 100 120 140 160 NORMAL STRESS SPSI) POLISHED ARGILLITE ON ARGILLITE, DRY FIGURE 7.I.7 ...- --- -.35 SHEAR DISPLACEMENTININCHES 100 ROCK TYPE: GRAYWACKE BOREHOLE: BM-2 SAMPLE: BO-71 DEPTH: 445.2` 60 SAMPLE AREA: 2.473 SO. IN. N a 60 w W a w 120= a 40 N �R=15' 20 0 0 20 40 80 80 100 120 140 160 NORMAL STRESS {PSI) POLISHED GRAYWACKE ON GRAYWACKE, WET 0.05 0.10 OJ5 0.20 0.25 0.30 0.35 SHEAR DISPLACEMENT IN INCHES 100 ROCK TYPE: GRAYWACKE BOREHOLE: BH-1 SAMPLE: 80-73 DEPTH: 429,0' BO SAMPLE AREA: 2.462 SO. IN. N a N 60 N w �p h a 40 fn 20 0 0 20 40 60 SO 100 120 MG 160 NORMAL STRESS (PSI} POLISHED GRAYWACKE ON GRAYWACKE, DRY 180 160 140 0 120 2 m O q 100 4 O cn LJ 60 A A Al 40 d fi]' /� d El 0 20 0 0 0.05 0.10 0.15 0.20 0,25 0.30 0.35 SHEAR DISPLACEMENT IN INCHES 100 ROCK TYPE: GRAYWACKE BOREHOLE: BH-2 SAMPLE: 80-71 DEPTH: 445.2' 80 SAMPLE AREA: 2,475 SQ.IN. N a E0 60 rc 4 40 _ �P=IS' N 20 �R=10' 0 0 20 40 60 80 100 120 140 060 NORMAL STRESS (PSI) POLISHED GRAYWACKE ON GRAYWACKE, DRY DEVIL CANYON DIRECT SHEAR TESTS SHEET 2 OF 3 LEGEND 4 PEAK FRICTION ANGLE �R RESIDUAL FRICTION ANGLE ® PEAK VALUES A RESIDUAL VALUES O NORMAL LOAD= 25 PSI NORMAL LOAD= 75 PSI El NORMAL LOAD-150 PSI FRICTION ANGLE ENVELOPE NOTES I. MAXIMUM SHEAR BOX DISPLACEMENT -0.3 INCHES 2. STRAIN RATE = 0.039 IN. / MIN. FIGURE 7.17 IBO °ao 0 000 o0 160 140 Fl 0 120 x 0 0 4 ? 100 rc a BO W 2 (11 6D 4011 Q o OQ000000° 20 0 0.05 0.10 0.15 0.20 0.25 0.30 0,35 SHEAR DISPLACEMENT IN INCHES 100 ROCK TYPE: GRAYWACKE BOREHOLE: BH-I SAMPLE: 60-51 A+B DEPTH: 554.5' BO SAMPLE AREA: 2.76 SO. IN. a N 60 oP•25°' a OR=23° 40 x h �=22°, C•6 PSI {r� tt 20 0 0 20 40 60 BO 100 120 €40 160 NORMAL STRESS (PSI) GRAYWACKE, NATURAL JOINT, SMOOTH, PLANAR, PART OPEN 6 4 2 O 0 0.05 0.10 0.35 0.20 0.25 0.30 0,35 SHEAR DISPLACEMENT IN INCHES 100 ROCK TYPE: GRAYWACKE BOREHOLE: BH-2 SAMPLE: 80-71 445.2 DEPTH: 445.2' /BO- -, a SAMPLE AREA: 2.473 SQ. IN. / w 60 U) OP=31° - ----� OR=27° N a 40 w _ N =27; C =8 PSI/ 20 0 0 20 40 60 BO 100 120 140 160 NORMAL STRESS (PSI) POLISHED GRAYWACKE ON MORTAR, BOND BROKEN DEVIL CANYON DIRECT SHEAR TESTS SHEET 3 OF 3 LEGEND (bp PEAK FRICTION ANGLE �R RESIDUAL FRICTION ANGLE ® PEAK VALUES A RESIDUAL VALUES 0 NORMAL LOAD = 25 PSI 0 NORMAL LOAD • 75 PSI El NORMAL LOAD a 150 PSI C APPARENT COHESION NOTES I. MAXIMUM SHEAR BOX DISPLACEMENT •0.3INCHES 2. STRAIN RATE-0.039 EN./MIN. FIGURE 7.17 IN- U W Q Lu 4 U O 10 20 30 UNCONFINED COMPRESSIVE STRENGTH (ksi ) ARGILLITE (AAI,USER) V) Lu 6 U z W x 7 U 4 ) O U- 0 ir 2 W m M z N=21 40 10 20 30 40 UNCONFINED COMPRESSIVE STRENGTH (ksi) ALL TL" S (l;l;l, U,3BF S.D. S.D. 10 20 30- — — UNCONFINED COMPRESSIVE STRENGTH ( ksi ) GRAYWACkE (AAI, U 5F) DEVIL CANYON JNCONFINED COMPRESSIVE STRENGTH TEST RESULTS ROCK N ARGILLITE 21 GRAYINACKE 16 MAFIC DIKE 2 TOTAL m 39 LEGEND N - NUMBER OF TESTS S.D. -STANDARD DEVIATION N=16 40 REFERENCE; LAB REPORT C`933,USBR 1960 FIGURE 7.18 10 z 0 200 F uj LL! "_ 300 x a LLJ 0 LEI J 0 400 x LEI m 0 m J a U F 500 LEI 600 700 800 K, COEFFICIENT OF PERMEABILITY (CM/SEC) 10-3 10 4 10-5 o-6 10-7 a Q 1 \ 1 v AVERAGE o PERMEABILITY 1 I � � I 1 MAXIMUM MINIMUM I 1 1 � ` e 1 \ O BASED ON: AAI 80-81 : BH-1-4, BH-5A-5B, BH-7 USER HOLES: DH-1, DH-5,DH-7,DH-8,DH-9, DH-I IC, DH-12A, DH-13,DH-14B DH-15 DEVIL CANYON. ROCK PERMEABILITY FIGURE 7.20 [j6j TEMPERATURE (°C) -2 -I 0 I 2 3 4 5 -5 -4 TEMPERATURE l°CS TEMPERATURE ('Cl I 1413,7 C 1402.6 1400 380 90 1360 340 BO 1320 F w 120 w 1300 w w LL J O Y � O g a 1200 a w w a n 160 1260 p 1240 200 1220 1200 240 1180 1160 280 LEGEND UTHOLOGY: IMM GROUND SURFACE 31WW TOP OF ROCK SOREHOLES: AH AUGER HOLE} ACRES AMERICAN INCORPORATED BH BORE HOLE DATA SOURCES - INDEX OF THERMISTOR READING DATES. a NOVEMBER 21,1980 o APRIL 19, 1981 x MAY 24, 101 ❑ JUNE 24, 19Bt o AUGUST 3,1981 • NOVEMBER 13, 1981 O DECEMBER 9, 1961 I:> JANUARY 7, 1982 1213A 0 3 -2 -1 0 1 2 3 4 5 -5 -4 -3 -2 -1 0 1 2 3 4 5 12117 1352,6 C STICK UP- 0,0 ------��-- `1346.5 g-. 1200 - FEET(1981) DIP - 60° . 131 O 1 180 90 - r ; \\I i,' 1320 40 1160 1300 1 140 BO 1280 1120 _ F^ � 1260 w w w w 120 _ H- w 120 w k 1100 J w 1240 - o z 2 LD = _ ZO 2 2 0 IOBO 1220 0 a a 160 w h w w 160 O 1060 1200 1040 200 1180 200 1020 I 1160 240 VVV 240 1000 1140 "Bo 2B0 1 120 200 BH-1 NOTES 1. LOCATION OF HOLES SHOWN ON FIGURE 5.2. 2, THERMISTOR STRINGS MANUFACTURED BY INSTRUMENTATION SERVICES IN FAIRBANKS, ALASKA. 3. BORINGS ARE INSTRUMENTED WITH PERMANENT MULTI -POINT THERMISTOR STRINGS , WITH TWO THERMISTORS AT EACH READING POINT. DATA FOR TWO POINTS 15 AVERAGED. 4. THERMISTOR READOUT BOX-KEITHLEY 172 A, USED FOR 1980 THRU 19BZ READINGS. 5. AUGER HOLES AH-GII THRU AH-GI4 CONTAIN THERMISTOR PROBES, BUT NO DATA WAS OBTAINED. 6. BORINGS ARE VERTICAL UNLESS A DIP IS INDICATED. BH-2 NOTE: DUE TO PROBLEMS ENCOUNTERED IN FIELD MEASUREMENTS, THE FOLLOWING ADJUSTMENTS WERE PERFORMED TO .CONFORM TO EXISTING RELIABLE DATA. THESE FIXED LATERAL SHIFTS MAY NOT CORRECT THE FULL MAGNITUDE OF THE DISCREPANCIES. ADJUSTMENT SUBTRACTED DATE OF READING FROM CALCULATED READING ('C) 4-26-81 13. 28 5-24-81 14.00 6-24-01 16.00 B- 3 -81 14.65 DEVIL CANYON THERMISTOR DATA-DAMSITE OH-4 NOTE: 7HERMISTOR DATA FOR 5-24-8I IS OUESTIONABLE AT 200 AND 250 FEET, SENSOR AT 250 FEET WAS ERRAT{C FOR 1-7-82 READING. -3 -2 -1 0 1 2 3•C SCALE 27 29 29 30 31 32 33 34 35 36 37•F FIGURE 7.21��� � I wl ... l i Ir T t n;iS xl �• '' TTK 23` 2� 7� 111E TTK GAGmy f - i • \TTK-27 �S-IaJM� .^---." - ! E hTk-26 ,-' I - 25 �E i K-6 A \\ co i1H - G 2 TTK%:. A€d-G4� pis TTK-17 „ � \ � TT�_2�1 j h R#YER L y ` y X/1- REFERENCE; BASE MAP FROM R SM,19B4— I" -200' DEVIL CANYON TOPOGRAPHY, RETRACED AT 25' CONTOURS USBR,1960 COE,1978 WCC, 1978 62 I ' k Gs � r� A€'I,1'd0"-m ATE DA,M f CEHI'Er�L€@�E ®EVIL CANYON BORROW SITE G PLAN BORROW SITE G (LOOKING NORTH) TEST TRENCH TT-Gl ILOOKING NORTH) LEGEND CONTACTS= -------- MAPPED LIMIT OF BORROW SITE OR ZONE BOREHOLES AND TEST PITS 0 AH-GI 1960-83,AAI AUGER BORING TTK-t7 PK-93 1958,USBR DOZER TRENCH TT-G€ 1981, AAI DOZER TRENCH GEOPHYSICAL SURVEYS= L� SW-i5 SEISMIC REFRACTION SURVEY END OR TURNING POINT -- 1976, SNANNON S WILSON OTHER: E f CROSS SECTION LOCATION (SEE NOTE 21 NOTES I. TYPICAL SECTIONS SHOWN ON FIGURE 7.23 2. FOR DETAILED GEOLOGY AND GEOLOGIC SECTIONS, SEE FIGURES 7.3 AND 7.4 THROUGH 7.10 3.SVRFICIAL GEOLOGY SHOWN ON FIGURE 7.2, 4, 25 FOOT CONTOUR INTERVAL ADDED FROM SOURCE MAP (REFERENCED( IN BORROW SITE ONLY, 5. BORROW SITE LIMITS BASED ON FIELD AND AIR PHOTO INTERPRETATION OF BORROW MATERIAL, FINAL LIMITS, SUBJECT TO RESULTS OF DESIGN INVESTIGATIONS. G_ BORROW MATERIAL ZONES INDICATE MAPPED VARIATIONS IN MATERIAL TYPE. ZONE I ALLUVIAL FAN / TERRACE DEPOSIT OF SAND AND GRAVELS. ZONE IL RIVER TERRACES, SIMILAR TO MATERIAL I. ZONE K CHEECHAKO CREEK OUTWASH, BOULDERY GRAVELS. ZONE IS ARGILLITE / GRAYWACKE TALUS DEPOSITS. 7. ENTIRE BORROW SITE LIES WITHIN PROPOSED DEVIL CANYON RESERVOIR LIMITS, 8, USBR, COE EXPLORATION LOGS AS REFERENCED. 9, AAl EXPLORATION LOGS SHOWN IN APPENDIX G. IO.PHOTOS TAKEN AUGUST, 1981. 0 200 400 FEET SCALE FIGURE 7.22 Enc 090c_-- AZIMUTH _®270° OF SECTIONS LEGEND F SUSITNA "I DIVER w I000 0 S50 EL.925= 900 F SUSITNA w w RIVER L, 1000 n 950 ...-EL.930i- 6 900 J „a F1 ;100 w Z ® 1000 a s w a SOD In RIVER TTK-7 TTK-1T AH-G4 TTK-20 AH-G2 1000 N. END — ,:�' TT-G2 950 EL.910¢ 900 SW-15 PROJECTED 5O' S TTK-26 .P-'---.o-N.....6._...�.—_TTK 25I° 16' SECTION E-E SECTION G-G SW-15 SW-15 PROJECTEDSO'N SUSITNA Zl\ RIVER AH-G3 AH-GI 1000 TTK 19 TT -GI N. END 950 b 900 1100 1000 — 900 1400 IADO 1300 -- 1300 SHALLOW _ ASSUME❑ _��� k 1200 DEDROCK-� 1200 a CHEECHAKO CREEK iu 1100 "�,.. •sue HOD 00 w w ASSUMED ` EL.975± -- y :- SHALLOWl IOOD BEDROCK `;Qa. .o, e..o oo�o, $. 0 0.• ..:i✓V - 1000 q,.,�.n°v b�n740 oO: 0e a�odd°a ooQ �.00=do.Q 4.•..i -:yl vi-�'°�t��_Q• a(7�a.0a.._.a.it.(?n:..00�.••w.n�^-'~o 900 900 SECTION J-J DEVIL CANYON BORROW SITE G SECTIONS CONTACTS �---- MATERIAL. LIMITS — ----- ASSUMED TOP OF ROCK LITHOLOGY; ITIN97ZW ARGILLITE ® GRAYWACKE OUTCROPS BOREHOLES Q TEST PITS: AH-GI 1900.01,AAI AUGER BORING [ TTK-IT 195B,USDR DOZER TRENCH iC TP K-93 1950,USBR HAND DUG TEST PIT. TT -GI 1901,AAI DOZER TRENCH GEOPHYSICAL SURVEYS: 4 SW-15 SEISMIC REFRACTION SURVEY ENO OR TURNING POINT -19T6,9HANNONaWILSOM NOTES I. SECTION LOCATIONS AND BORROW SITE PHOTO SHOWN ON FIGURE 7.22. 2. FOR DETAILED GEOLOGY AND GEOLOGIC SECTIONS, SEE FIGURE 7.3 AND 7.4 THROUGH 7.10. 3. SURFICIAL GEOLOGY SHOWN ON FIGURE TZ. 4. VERTICAL AND HORIZONTAL_ SCALE 1;1, 5. SECTION ELEVATIONS FROM REFERENCED BASE MAP. G.BORROW S$TE LIMITS BASED ON FIELD AND AIR PHOTO INTERPRETATION. FINAL MAPPED LIMITS OF BORROW MATERIALS, SUBJECT TO RESULTS OF DESIGN INVESTIGATIONS. T- BORROW MAl'ERIAL ZONES INDICATE MAPPED VARIATIONS IN MATERIAL TYPE. ZONE I AI-LUYJAL. FAN / TERRACE DEPOSIT OF $AND IT-) AND GRAVEL-, COARSER AT DEPTH (T6) ZONE ]I RIVER TFRRACES,SIMILAR TO MATERIAL Z ZONE lQ CHEECHAKO CREEK OUTWASH,BOULOERY GRAVELS ZONE ]W ARGILL#TE / GRAYWACKE TALUS DEPOSITS 0,USBR,COE EXPLORATION LOGS AS REFERENCED, 9, AAI EXPLORATION LOGS SHOWN IN APPENDIX F. 10.EXPLORATIONS PROJECTED UP TO MO' ONTO SECTIONS. 11 SECTIONS STOPPED AT SUSITNA RIVER LEVEL. O 100 200 FEET SCALE FIGURE 723 [9 Al� J4816M dq a911000 3u83Jad 0 pQ N M pp 1� pC� W Q �` � Q v' p 0 N cn U tv W C7 O Ln U- Z u N Q Q w ITF 0 ® 0 0 d Fg0 9 N i 0 8 / d L 0 L. W z r w i cu E aN� U C9 f P_ W / Q O C13L W Z La H E / � / o e v N � � v J W c W / W C9 F a ul °o / / if U / / / / in / / M _ 0 8 W a - m / w a � co m Q u o m N W h v 0 � � o z e � J J 0 0 O In � O i— g 0� S o o s a lWaM Aq aaul- iti=fififif�fifif��fi�� �ffflfffif��ffififi fitififififif�lfifif�ti �■wswwwww�ww■��wwwww��■�w wriri■wwwwww�www�rwwww��tw fimfi���titi�=� ww LEGEND I N 3,212,000 MN 5,2I4,000.... N 3,210g0i.'4A �X QUARRY SITE D-80-82 L- 1 e"`" AMS,11 E 9 o '2 0 REFERENCE- BASE MAP FROM USGS 1.63,360 ALASKA QUADRANGLE TALKEETNA MOUNTAINS (D-5). COORDINATES IN FEET, ALASKA STATE PLANE (ZONE 4) ACKUP Q DEVIL CANYON QUARRY SITE K ®-.— MATERIAL LIMITS ®' SAMPLE LOCATION NOTES 1. CONTOURS TRACED FROM ENLARGED, REFERENCED BASE MAP, AT 100' INTERVAL. 2.MATERIAL LIMIT SHOWN IS OUTCROP LIMIT AS DETERMINED FROM AIR PHOTO INTERPRETATION. NORTH FACES OF SITES ARE EXPOSED ROCK CLIFFS, AND LOCATION OF SAMPLES. 3.QUARRY MATERIAL IS A BIOTITE GRANODIORITE WITH SOME ARGILLITE INCLUSIONS. MAPPED AREA CONSISTS OFA SERIES OF NORTH- FACING SHEAR BLUFFS 50-100' IN HEIGHT, FORMING THE FACE OF A DIORITE PLUTON WITH EXPOSURE IN EXCESS OF 1/2 SQUARE MILE. 4. ENTIRE QUARRY SITE LIES OUTSIDE OF PROPOSED RESERVOIR LIMITS. FIGURE 7.26 011 REFERENCES 1. Acres American Incorporated, Susitna Hydroelectric Project, Feasi- bility Report, 1982. 2. American Geological Institute, Glossary of Geology, Kingsport Press, Tennessee, 805 p, 1973. 3. ASCE, Rock Engineering for Foundations and Slopes, Vol. 1 and 2, August, 1976. 4. ASCE, Symposium on Underground Rock Chambers, Phoenix, Arizona, January, 1971. 5. Billings, M. P., Structural Geology, Prentice -Hall Inc., New Jersey, pp. 108-114, 1962. 6. Chapin, T., "The Nelchina - Susitna Region, Alaska," U. S. Geological Survey Bulletin 668, 1918. 7. Csejtey, B., Jr., "Reconnaissance Geologic Investigation in the Talkeetna Mountains, Alaska", U. S. Geological Survey, Open File Report 74-147, pp. 48, 197 . 8. Csejtey, B., Jr., "Tectonic Implications of a Late Paleozoic Vol- canic Arc in the Talkeetna Mountains, Southcentral Alaska", Geology, Vol. 4, No. 1, 1976. 9. Csejtey, B., Jr., "The Denali Fault of Southern Alaska: The Case for Minor Rather than Major Displacement", Transactions American Geophysical Union, Vol. 61, No. 46, p 1114. 10. Csejtey, B., Jr., Foster, H. L., and Nokleberg, W. J., "Cretaceous Accretion of the Talkeetna Superterrain and Subsequent Devel- opment of the Denali Fault in Southcentral and Eastern Alaska", Geological Society of America, Abstracts with Programs, p. 409, 1980. 11. Csejtey, B., Jr., Nelson, W. H. , Jones, D. L.", Si 1 berl i ng, N. J., Dean, R. M., Morris, M. S., Lanphere, M. A., Smith, J. G., and Silberman, M. L., "Reconnaissance Geologic Map and Geochrono- logy, Talkeetna Mountains Quadrangle, Northern Part of Anchor- age Quadrangle, and Southwest Corner of Healy Quadrangle, Alaska", U. S. Geological Survey, Open File Report 78-558A, 62 p. 1978. 12. Dames & Moore Inc., Subsurface Geophysical Exploration - Proposed Watana Damsite on the Susitna River, Alaska, Department of the Army, Contract Number DACW-76-C-0004, 1975. ACRE3 REFERENCES (Continued) 13. Deere, D. U., "Technical Description of Rock Cores for Engineering Purposes", Rock Mechanics and EngineeringGeology, Vol. 1, 1963. 14. Deere, D. U., "Geologic Considerations" in, Stagg, K.G., and Zienkiewicz, O.C., (eds.), Rock Mechanics in Engineering Practice, John Wiley and Sons, 1968. 15. Deere, D. U., Hendron, A. J., Jr., Patton, F. D., and Cording, E. J., "Design of Surface and Near -Surface Construction in Rock", 8th Symposium on Rock Mechanics, Minnesota, 1966. 16. Deere, D. U., and Miller, R. P., "Engineering Classification and Index Properties for Intact Rock", Technical Report No. AFWL-TR--65-116, U.S. Air Force Weapons Laboratory, Kirkland Air Force Base, New Mexico, 1966. 17. Deere, D. U., Monsees, J. E., Peck, R. B., and Schmidt, B., Design of Tunnel Liners and Support Systems, University of Illinois, 1969. 18. Detterman, R. L., Plafker, G., Hudson, T., Tysdal, R. G., and Pavoni, N., "Surface Geology and Holocene Breaks Along the Susitna Segment of the Castle Mountain Fault, Alaska", U. S. Geological Survey, Miscellaneous Field Studies Map MF-618, 1974. 19. Ferrians, 0. J., Jr., "Permafrost Map of Alaska", U.S. Geological Survey, Miscellaneous Geological Investigations Map I-445, Scale 1:250,000, 1965. 20. Gedney, L. and Shapiro, L., Structural Lineaments, Seismicity and Geology of the Talkeetna Mountains Area, Alaska, Geophysical Institute, University of Alaska, prepared f or U. S. Army Corps of Engineers, 1975. 21. Hendron, A. J., Jr., "Mechanical Properties of Rock", in,Stagg, K. G., and Zienkiewicz, 0. C. (eds.), Rock Mechanics in Engineering Practice, John Wiley and Sons, 1968. 22. Hillhouse, J. W., "Paleomagnetism of the Triassic Nikolai Green - stone, McCarthy Quadrangle, Alaska", Canadian Journal of Earth Science, Vol. 14, pp.2578-2592, 1977. 23. Hoek, E., and Brown, E. T., Underground Excavations in Rock, Institute of Mining and Metallurgy, London, 1980. 24. Johnston, G. H., (ed.), Permafrost Engineering Design and Construction, John Wiley and Sons, 1981. REFERENCES (Continued) 25. Jones, D. L. , and Si 1 berl ing, N. J. , "Mesozoic Stratigraphy, the Key to Tectonic Analysis of Southern and Central Alaska", U.S. Geological Survey, Open File Report 79-1200, 37 p., 1979. 26. Jones, D. L., Si 1 berl i ng, N. J., Csejtey, B. , Jr., Nelson, W. H. and Bl oome, C. D., "Age and Structural Significance of the Chulitna Ophiolite and Adjoining Rocks, Southcentral Alaska", U. S. Geological Survey, Professional Paper 1121-A, 1978. 27. Jones, D. L., Silberling, N. J., and Hillhouse, J., "Wrangellia - A Displaced Terrain in Northwestern North America", Canadian Journal of Earth Science, Vol. 14, pp.2565-2577, 1977. 28. Kachadoorian, R., "Geology of the Devil Canyon Damsite, Alaska", U. S. Geological Survey Report to U. S. Bureau of Reclama- tion, 1958. 29. Kachadoorian, R., "Geology of the Devil Canyon Damsite, Alaska", U. S. Geological Survey, Open File Report 74-40, 1974. 30. Karlstrom, T. N. V., "Quaternary Geology of the Kenai Lowland and Glacial History of the Cook Inlet Region, Alaska", U. S. Geological Survey, Professional_ Paper 443, 1964. 31. McRoberts, E. C., and Morgenstern, N.R., "The Stability of Thawing Slopes", Canadian Geotechnical Journal, Volume II, No. 4, pp. 447-469, 1974. 32. NPAS (North Pacific Aerial Surveys, Inc.), Control Survey Manu- scripts for R&M Consultants, 1981. 33. Packer, D. R., Brogan, G. E., and Stone, D. a., "New Data on the Plate Tectonics of Alaska", Tectono h sits, Vol. 29, pp. 87- 102, 1975. 34. Pewe, T. L., "Quaternary Geology of Alaska", U. S. Geological Survey, Professional Paper 835, 1975. 35. R & M Consultants, Aerial Topographic Map of Devil Canyon Reser- voir, Scale 1 inch = 400 feet, 1981. 36. R & M Consultants, Devil Canyon Climate Data, Aril 1980 through July 1, _1981, 1981a. 37. R & M Consultants, Watana Climate Data, September, 1980 _through May, 1981, 1981 b. ACRES REFERENCES (Continued) 38. Richter, D. H. and Jones, D. L., "The Structure and Stratigraphy of Eastern Alaska Range, Alaska", American Association of Petroleum Geologists, Memoir 19, pp. 408-410, 1973. 39. Shannon & Wilson, Inc., Seismic Refraction Survey, Susitna Hydroelectric Project, Watana and Devil Canyon Damsites, 1978. 40. Smith, T. E., "Regional Geology of the Susitna - MacLaren River Area", Alaska Division of Geological and Geophysical Surveys, Annual Report, 1974. 41. Smith, T. E., Bundtsen, T.K., and Trible, T. C., "Stratabound Copper -Gold Occurrence, Northern Talkeetna Mountains, Alaska", Alaska Division of Geological and _Geophysical Survey, Open File Report 72, 1975. 42. Stone, D. B., and Packer, D. R., "Tectonic Implications of Alaska Peninsula Paleomagnetic Data", Tectonophysics, Vol. 37, pp. 183-201, 1977. 43. Travis, R. B., "Classification of Rocks", Quarterly of the Colorado School of Mines, Vol. 50, No. 1, 1955. 44. Turner, D. L. and Smith, T. E., "Geochronology and Generalized Geology of the Central Alaska Range, Clearwater Mountains, and Northern Talkeetna Mountains", Alaska Division of Geological and Geophysical Surveys, Open File Report 7.2, 1974. 45. U.S. Array Corps of Engineers, Hydroelectric Power and Related Purposes, Upper Susitna River Basin, Southcentral Railbelt Area, Alaska, Interim and Final Feasibility Reports, 1975 and 1978. 46. U.S. Army Corps of Engineers, Petrographic Examination of Led e Rock, Re ort Series Numbers 1 and 5 78/138 and 78/207 , Missouri River Division, Omaha, Nebraska, 1978. 47. U.S. Army Corps of Engineers, Susitna Project _Geolo2y Field and Survey Books, Numbers 1 through 28, unpublished, 1978. 48. U.S. Array Corps of NX Rock Cores North Pacific gon, 1978. ACB6 Engineers, Susitna for Talkeetna anc -)ivision Materials Project, Report of Watana Sources 7E Laboratory, Troutda Tests on e, ure- REFERENCES (Continued) 49. U.S. Array Corps of Engineers, Report of Tests on NK Rock Cores and Ledge Rock, Talkeetna Flood Control Project, North Pacific Division Materials Laboratory, Troutdale, Oregon, 1979. 50. U.S. Bureau of Reclamation, Devil Canyon Project, Potential Development: Design Notes and Calculations, 1952. 51. U.S. Bureau of Reclamation, "Engineering Geology Report, Feasibil- ity Stage, Devil Canyon Dam, Devil Canyon Project", Alaska Geologic Report No. 7, 1960. 52. U.S. Bureau of Reclamation, "Laboratory Tests On Concrete Aggre- gate from Devil Canyon Damsite, Alaska", Concrete Laboratory Report C-932, 1959. 53. U.S. Bureau of Reclamation, "Laboratory Tests of Foundation Rock Cores from Devil Canyon Damsite, Devil Canyon Project - Alaska", Concrete Laboratory Report C-933, 1960. 54. Van Eysinga, F.W.B., Geologic Time Table, 3rd Edition, Elsevier Scientific Publishing Co., Amsterdam, 1975. 55. Varnes, D. J., "Landslide Types and Processes", in,Eckert, E.B., (ed.), Landslides and Engineering Practice, Highway Reserve Board Special Report No. 29, pp. 20-45, 1957. 56. Whitten, D.G.A., and Brooks, J.R.V., A Dictionary of Geology, Penguin Books, England, 495 p., 1972. 57. Woodward -Clyde Consultants, Final Report - Susitna Hydroelectric Project, Seismic Refraction Survey-, 1980. 58. Woodward -Clyde Consultants, Interim Report on Seismic Studies for Susitna Hydroelectric Project, 1980. 59. Woodward -Clyde Consultants, Final Report - Susitna Hydroelectric Project Seismic Refraction Surve , 1981. 60. Woodward -Clyde Consultants, Final Report on Seismic Studies for Susitna Hydroelectric Project, 1982. RCBfS GLOSSARY* Active Layer or Active Zone -- The surf ici al layer of ground above the permafrost table that thaws each summer and refreezes each fall, and therefore represents the fluctuating freezing front of the permafrost table. Alluvial - Pertaining to or composed of alluvium or deposited by a stream or running water. Alluvial Fan - A low, outspread, relatively flat to gently sloping mass of loose rock material, shaped like an open fan or a segment of a cone, deposited by a stream at the place where it issues from a narrow moun- tain valley upon a plain or broad valley, or where a tributary stream is near or at its junction with the main stream or whenever a constric- tion in a valley abruptly ceases or the gradient of the stream suddenly decreases. Alluvium - A general term for clay, silt, sand, gravel or similar unconsolidated detrital material deposited during comparatively recent geologic time by a stream or other body of running crater as a sorted or semi sorted sediment in the bed of the stream or on its flood plain or delta. Alpine Glacier - Any glacier in a mountain range except an ice cap or ice sheet. Alteration - Any change in the mineralogic composition brought about by physical or chemical means, especially by the action of hydrothermal solutions. Andesite - A dark colored, fine grained extrusive rock that when pro- phyritic contains phenocrysts composed primarily of plagioclase and one or more of the mafic minerals (biotite, hornblende, pyroxene) and a groundmass composed generally of the same minerals as the phenocrysts. The extrusive equivalent of a diorite. Annual Frost or Seasonal Frost - Frost which formed in the immediately previous freezing season and will thaw during the summer thaw season. By definition, all frost and frozen ground in the active layer. Aqui cl ude - A body of relatively impermeable material that is capable of absorbing water slowly but functions as an upper or lower boundary of an aquifer and does not transmit ground water rapidly enough to supply a well or spring. *Definitions modified from References 2, 13, 24, and 56. IpcA�s GLOSSARY (Continued) A u�if^er - A body of rock that contains sufficient saturated permeable material to conduct groundwater and to yield significantly greater quantities of groundwater than the adjacent units. Argillaceous - Pertaining to, largely composed of, or containing clay size particles or clay minerals. Argiillite - A compact rock, derived either from mudstone or shale that has undergone a somewhat higher degree of induration than is present in mudstone or shale but that is less clearly laminated than and without the fissility of shale, or that lacks the cleavage distinctive of slate. Basalt - A dark to medium dark colored, extrusive and intrusive (as dikes mafic igneous rock composed chiefly of calcic plagioclase and pyroxene in a glassy or fine-grained groundmass. Batholith - A large, generally discordant, plutonic mass that has more than 40 square miles in surface exposure and is composed predominantly of medium to coarse grained rocks. Bedrock - A general term for the rock, usually solid that underlies soil or other unconsolidated, surficial material. Bimodal Flow/Slide - A slide that consists of a steep headwall, con- taining ice or ice -rich sediment, which retreats in a retrogressive fashion through melting, forming a debris flow, which slides down the face of the headwall to its base. Block Slide/Glide - A translational landslide in which the slide mass remains essentially intact, moving outward and downward as a unit, most often along a pre-existing plane of weakness, such as bedding, joints and faults. Break in Slope - A marked or abrupt change or inflection in a slope or profile, commonly meant to indicate the transition from steep valley or gorge walls to more rounded, flatter crest or plateau levels. Breccia - Fragmented rock whose components are angular; used here to refer to crushed rock related to shearing. Carbonate - A mineral compound characterized by a fundamental anionic structure of CO3+, generally refers to calcite. Cataclastic Rock - A rock containing angular fragments that have been produced by the crushing and fracturing of pre-existing rock as a result of mechanical forces in the crust. GLOSSARY (Continued) Chlorite - A group of greenish, platy minerals, which are associated with and resemble the micas. Chlorite is widely distributed especially in low-grade metamorphic rocks, or as alteration products of ferromag- nesium minerals in igneous rocks. Colluvium Deposits - A general term applied to any loose, heterogene- ous, and incoherent mass of soil material or rock fragments deposited chiefly by masswasting, usually at the base of a steep slope or cliff. Compressive Strength - The maximum uniaxial compressive stress that can be applied to a material, under given conditions, before failure occurs. Country Rock - The rock intruded by and surrounding an igneous intru- sion. Crystalline - Said of a rock consisting wholly of crystals or fragments of mineral crystals; especially so in an igneous rock developed through cooling from a molten state and containing no glass. Dacite - A fine-grained extrusive rock with the same general composi- tion as a quartz diorite or granodiorite. Degrading Permafrost _Zone - A decrease in thickness and/or aerial extent of permafrost because of natural or artificial causes as a result of climatic warming and/or change of terrain conditions such as disturbance or removal of an insulating vegetation layer by fire or human means. Depth of Zero Annual Amplitude - The depth at which the annual effect of surface temperatures is not detectable. Below the depth of zero annual amplitude, the ground temperature changes only as a result of sustained thermal influences on the average ground or surface tempera- ture, which will elevate or deepen the depth of zero annual amplitude. Diabase - An intrusive rock whose main components are calcic plagio- clase labradorite) feldspar and pyroxene, which is characterized by lath shaped feldspar crystals. Dike - A tabular igneous intrusion that cuts across the planar struc- tures of the surrounding rock. Diorite - A group of plutonic rocks intermediate in composition between acidic and basic rocks, characteristically composed of dark colored amphibole (especially hornblende), plagioclase feldspar, pyroxene and sometimes a small amount of quartz. Dip - The angle that a structural surface, for example, a bedding plane or joint, makes with the horizontal, measured perpendicular to the strike of the structure. gCN6 GLOSSARY (Continued) Direct Shear Test - Test measuring the sliding resistance along discon- tinuities. Eually has two components, friction and cohesion, though cohesion may or may not be present. A peak angle implying maximum resistance, and a residual angle depicting the shear strength after larger shear displacements, are determined. Drunken Forest - A group of trees leaning in a random orientation; usu- ally associated with thermokarst topography, reflecting local slope in- stability. Dynamic Elastic Properties - Young's Modulus and Poisson's Ratio deter- mined using acoustic shear and compressional wave velocities of the material (ASTM 2845-69 (1976)). Episode - A term used informally and without time implications for a distinctive and significant event or series of events in the glacial history of a region, each episode representing a different erosional or depositional environment. Esker - A long, low, narrow, sinuous, steep -sided ridge or mound com- posed of irregularly stratified sand and gravel that was deposited by a subglacial or englacial stream flowing between ice walls or in an ice tunnel of a continuous glacier and was left behind when the ice melted. Faci es Change - A lateral or vertical variation in the 1 i thol ogi c or paleontologic characteristics of contemporaneous sedimentary deposits. It is caused by, or reflects, a change in the depositional environ- ment. Fault - (see Shear). Felsic - A general term applied to an igneous rock having light-colored minerals in its mode. The opposite of mafic. Flow Structure - The texture of an igneous rock, characterized by a wavy or swirling pattern in which platy or prismatic minerals are oriented along planes of lamellar flowage in fine grained and glassy igneous rocks. Flows - A broad type of movement that exhibits the characteristics of a viscous fluid in its downslope motion. Foliation - A general term for a planar arrangement of textural or structural features in any type of rock. Fracture - A general term for any break due to mechanical failure by stress in a rock. Fracture includes cracks, joints and faults. Fracture Zone - An area characterized by very close to closely spaced joints where no measurable relative movement has occurred. ACRIS GLOSSARY (Continued) Geothermal Gradient - The increase depth. The rate commonly varies (1°C/22 meters to 1°C/160 meters). of temperature in the earth with from 1°F/40 feet to 1°F/300 feet Glaciofluvial - Pertaining to the meltwater streams flowing from glac- ier ice and especially to the deposits and landforms produced by such streams such as kame terraces and outwash plains. Gouge - Rock material that has been ground to a uniformly fine particle size of clay or fine silt sizes. Grain Size - The general dimensions (average diameter) of the particles in a sediment or rock or of the grains of a particular mineral that make up a sediment or rock: Fine - less than 1 mm Medium - lmm to 5 mm Coarse - Greater than 5 mm Granodiorite - A group of coarse grained plutonic rock intermediate in composition between quartz diorite and quartz monzonite. Gray - An old rock name that has been variously defined but is now generally applied to a gray or greenish gray, very hard, tough and firmly indurated, coarse grained sandstone that has a subconchoidal fracture and consists of poorly sorted and extremely angular to subang- ular grains of quartz and feldspar with an abundant variety of small, dark rock and mineral fragments embedded in a compacted, partly meta- morphosed clayey matrix containing fine-grained micaceous and chloritic minerals. Groundmass - The interstitial material of a porphyritic igneous rock; it is relatively more fine grained than the phenocrysts and may be glassy or microcrystalline. Ground Temperature Envelope - An inverted cone -shaped zone including the maximum and minimum temperature as a function of depth on a ground temperature regime plot. Ranges from annual minimum air temperature at zero depth, showing maximum variation in temperature, to zero annual variation at the Depth of Zero Annual Amplitude. Hematite - (see Iron Oxide) Hydraulic _Head - The height of the free surface of a body of water above a given subsurface point. Hydrothermal - Of or pertaining to heated water, to tht action of heated water or to the products of the action of heated water used in relation to hydrothermal alteration of minerals. ACRE GLOSSARY (Continued) i Ice, Massive - A comprehensive term used to describe large (with dimen- sions at least 2 to 25 inches) masses of underground ice, including ice wedges, pingo ice and ice lenses. f Ice, Segregated_ - Ice formed by the migration of pore water to the freezing plane where it forms into discrete lenses, layers or seams ranging in thickness from hairline to greater than 30 feet. Ice Lens - 1. A dominantly horizontal lens -shaped body of ice of any dimension. 2. Commonly used for layers of segregated ice that are parallel to the ground surface. The lenses may range in thickness from hairline to as much as 30 feet. Igneous - Rock or mineral that solidified from molten or partly molten material, that is, from a magma. Inclusions - A fragment of older rock in an igneous rock to which it is not genetically related. Intermontane - Situated between or surrounded by mountains, mountain ranges, or mountainous regions. Iron Oxide - A general field term for a group of orange to brown amorphous naturally occurring hydrous ferric oxides whose actual miner- alogy was not identified in this study. It is a common secondary material formed by weathering of iron or iron -bearing minerals. Isotherm - A line connecting points of equal temperature. Joint - A surface of actual or potential fracture or parting in a rock without measureable displacement. Joint Set - A regional pattern or group of parallel joints. Joint Spacing - The interval between joints of a particular joint set, measured on a line perpendicular to the joint planes: Joint Spacing Interval Very close < than 2 in. Close 2 in. to 1 ft. Moderately close 1 ft. to 3 ft. Wide 3 ft. to 10 ft. Very Wide Greater than 10 ft. Kame - A long, low, steep -sided hill, mound, knob, hummock or short irregular ridge, composed chiefly of poorly sorted and stratified sand and gravel deposited by a subglacial stream as an alluvial fan or delta against or upon the terminal margin of a melting glacier, and generally aligned parallel to the ice front. Lacustrine Deposits - Pertaining to, produced by, or formed in a lake or lakes. RCNES GLOSSARY (Continued) Latite - A porphyritic extrusive rock of intermediate composition. Lithic - A descriptive term applied to rock fragments occurring in a later formed rock. Limonite - (See Iron Oxide) Mafic - Said of an igneous rock having dark -colored minerals in its mode - opposite of felsic. Metamorphism - The mineralogical and structural adjustments of solid rock to physical and chemical conditions which have been imposed at depth below the surface zones of weathering and cementation, and which differ from the conditions under which the rocks in question originat- ed, resulting in visible modifications of the rock properties. Moraine - A mound, ridge or other distinct accumulation of unsorted, unstratified glacial drift, predominantly till, deposited chiefly by direct action of glacial ice in a variety of topographic land forms that are independent of control by the surface on which the drift lies. Multiple Regressive Flow - Forms a series of arcuate concave downslope ridges as it retains some portion of the prefailure relief. Multiple Retrogressive Flow/Slide - Series of arcuate blocks concave towards the toe, that step backwards higher and higher towards the headwall. Normal Fault - A fault in which the overlying side appears to have moved downward relative to the underlying side. Oroceny - The process of forming mountains, particularly by folding and thrusting. Outwash - Stratified detritus, chiefly sand and gravel, removed or "washed out" from a glacier by meltwater streams and deposited in front of or beyond the terminal moraine or the margin of an active glacier. The coarser material is deposited closer to the ice. Overburden - The soil, silt, sand, gravel, or other material overlying bedrock, either transported or formed in place. Palsa - A round or elongated hillock or mound, maximum height about 30 feet, composed of a peat layer overlying mineral soil. It has a peren- ially frozen core that extends from within the covering peat layer downward into or toward the underlying mineral soil. Patterned Ground - A general term for any ground surface of surfi ci al soil materials exhibiting a discernible, more or less ordered and sym- metrical, microphysiographic pattern. Used in this report as descrip- tive of frost wedge patterning. GLOSSARY (Continued) Perched Ground Water - Unconfined ground water separate from an under- lying main body of groundwater by an unsaturated zone with very low permeability. Perched Water Table - The water surface of a body of perched ground water. Permafrost - The thermal condition in soil or rock of temperatures below 32°F (O°C) persisting over at least two consecutive winters and the intervening summer; moisture in the form of water and ground ice may or may not be present. Earth materials in this thermal condition may be described as perenially frozen irrespective of their water and ice content. Permafrost, Continuous - Permafrost occurring everywhere beneath the exposed land surface throughout a geographic regional zone, with the exception of widely scattered sites (such as newly deposited unconsoli- dated sediments) where the climate has just begun to impose its influ- ence on the ground thermal regime and will cause the formation of con- tinuous permafrost. Permafrost, Discontinuous - Permafrost occurring in some areas beneath the ground surface throughout a geographic regional zone where other areas are free of permafrost. Permeability - The property or capacity of a porous rock, sediment, or soil for transmitting a fluid without impairment of the structure of the medium. Phenocasts - The relatively large crystals which are found set in a finer -grained groundmass. Phyll_ite - An argillaceous rock commonly formed by regional metamor- phism and intermediate in metamorphic grade between slate and mica schist. Minute crystals of mica and chlorite impart a silky sheen to the surfaces of cleavage. Piedmont Glacier - A thick continuous sheet of ice at the base of a mountain range, resting on land, formed by the spreading out and coalescing of valley glaciers from the higher elevations of the moun- tains. Pluton - An igneous intrusion. Plutonic Rock - An igneous rock formed at considerable depth by crys- tallization of magma or by chemical alteration. Point Load Test - A test indirectly measuring compressive strength by loading samples diametrically, measuring the splitting load and converting that to compressive strength. RCRlS GLOSSARY (Continued) Polygonal Ground - A type of patterned ground consisting of a closed roughly equidimensional figure bounded by several sides, commonly more or less straight but some or all of which may be irregularly curved. A polygon may be either "low center" or "high center" depending on whether its center is lower or higher than its margins. Porphyry - An igneous rock of any composition that contains conspicuous phenocrysts in a fine-grained groundmass. Por h roblast - The larger more or less euhedral crystals formed in metamorphic rocks which have grown during the process of metamorphism. Proglaciai - Immediately in front of or just beyond the outer limits of a glacier or ice sheet, generally at or near its lower end; said of lakes, streams, deposits and other features produced by or derived from the glacier ice. Relict - Said of a topographic feature that remains after other parts of the feature have been removed or have disappeared. Reverse Fault - A fault in which the overlying side appears to have moved upward relative to the underlying side. Rhyoli_te - A group of extrusive igneous rocks generally porphyritic and exhibiting flow texture; the extrusive equivalent of a granite. RQD (Rock Quality Designation) - A modified form of recording rock core recovery. The RQD is the ratio of the total length of core pieces, 4 inches and larger, to the length of the coring run actually drilled. RQD is expressed in percent. Rotational Slide - A landslide in which shearing takes place on a well defined, curved shear surface, concave upward in cross-section, produc- ing a backward rotation head of the in the displaced mass. Seismic Refraction - A type of seismic exploration based on the mea- surement of seismic energy as a function of time after the shot, or initial energy impulse, and of the distance from the shot, by determin- ing the arrival time of seismic waves which have traveled through over- burden and/or bedrock in order to map layers in the overburden and the top of the bedrock surface. Seismic Velocity_ - The rate of propogation of an elastic wave, measured in feet per second. The wave velocity depends upon the type of wave, as well as the elastic properties and density of the earth material through which it travels. Shear - A surface or zone of rock fracture along which there has been measurable displacement. RCBES GLOSSARY (Continued) Shear Strength - A material's resistance to shear failure. Intact mat- erials possess both cohesive and frictional resistance. Discontinui- ties have frictional resistance but may or may not have cohesive resis- tance. Frictional resistance of discontinuities may have two compon- ents, one depicting planar surface sliding resistance and the other depicting surface roughness. Skin Flow - The detachment of a thin veneer of vegetation and mineral soi ll v4ith subsequent movement over a planar inclined surface, usually indicative of thawing, fine-grained overburden over permafrost. Slickenside - A polished and smoothly striated surface that results from friction along a fault/shear plane. Slides - Landslides exhibiting a more coherent displacement; a greater appearance of rigid body motion. Solifluction Flow - Ground movements restricted to the active layer and generally requires fine-grained soils caused by melting of saturated soils. Static Elastic Properties - Young's Modulus and Poisson's Ratio measur- ed during unconfined compression tests (ASTM D 3148-80). Strata - Plural of stratum. Strati ra hic Column - A composite diagram that shows in a single column the subdivisions of part or all of the sequence of stratigraphic units of a given locality or region so arranged as to indicate their relations to the subdivisions of geologic time and their relative posi- tions to each other. Stratigrraphy - The arrangement of strata, especially as to geographic position and chronologic order of sequence. Stratum - A tabular or sheet -like mass or a single and distinct layer, of homogeneous or gradational sedimentary material (consolidated rock or unconsolidated earth) of any thickness, visually separable from other layers above and below by a discrete change in the character of the material deposited or by a sharp physical break in deposition, or by both. Strike - The direction or trend that a structural surface, for example, a bedding or fault plane, describes as it intersects the horizontal. Strike Slip Fault - A fault, the actual movement of which is parallel to the strike of the fault. Talus - Rock fragments of any size or shape (usually coarse and angu- lar derived from and lying at the base of a cliff or very steep, rocky slope. RCNS� GLOSSARY (Continued) Tensile Strength - The maximum applied tensile stress that a body can withstand before failure occurs. Terrace - Any long, narrow, relatively level or gently inclined sur- face, generally less broad than a plain, bounded along one edge by a steeper descending slope and along the other by a steeper ascending slope. Terrace Deposits - A general term used to describe alluvial benches along the side of a stream or river valley, which are no longer within the normal floodplain of the body of water. Used in contrast to active river alluvium, within the present channel, and flood plain deposits which lie within the current hydrologic regime, but outside of annual flood limits. Thalweg - The line connecting the lowest or deepest points along a stream bed or valley, whether under water or not. Applied in this report to include the lowest point of flow in a potential aquifer. Thermistor - A thermally sensitive resistor employing a semiconductor with a large negative resistance -temperature coefficient, used as an electrical thermometer. Thrust Fault - A reverse fault with a dip of 45' or less. Horizontal compression rather than vertical displacement is its characteristic feature. Till - Unsorted and unstratified drift, generally unconsolidated, deposited directly by and underneath a glacier without subsequent reworking by water from the glacier and consisting of a heterogeneous mixture of clay, sand, gravel and boulders varying widely in size and shape. Tundra - A treeless, generally level to undulating region of lichens, mosses, sedges, grasses and some low shrubs, including dwarf willows and birches, which is characteristic of both the Arctic and higher alpine regions outside of the Arctic. Unit Weight - A term applied, especially in soil mechanics, to the weight per unit volume. Varve - A sedimentary bed or lamina or sequence of laminae deposited in a body of still water within one year's time; specifically a thin pair of graded glaciolacustrine layers seasonally deposited (usually by meltwater streams) in a glacial lake or other body of still water in front of a glacier. Volcanic Rock - A generally finely crystalline or glassy igneous rock resulting from volcanic action at or near the earth's surface, either ejected explosively or extruded as lava. The term includes near -sur- face intrusions that form a part of the volcanic structure. RCRES GLOSSARY (Continued) Weathering - The destructive process or group of processes constituting that point of erosion whereby earthy and rocky materials on exposure to atmospheric agents at or near the earth's surface are changed in char- acter (color, texture, composition, firmness or form), with little or no transport of the loosened or changed material. Iw�AEsl