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r~· ) i .; i~ -~ 'l1 -> " ,_ \~ ,, . ' .I 'i LJ J ~ tJ I. ~ u u u u u u OO&OO~&c(g@£®©© Susitna Joint Venture Docurr:ent Number Please Return To DOCUMENT CONTROL SUSITNA HYDROELECTRIC PROJECT Prepared by: 1982. Sl}PPLEMENT TO THE 1980-81 GEOTECHNICAL REPORT VOLUME 1 TEXT DECEMBER 1982 ..____ALASKA POWER AUTHORITY_· ---..J i i I i :I I I I I I I I , I I I I I I I I I I I Prepared by: _________ .__ __ , _______ _ SUSITNA HYDROELECTRIC PROJECT 1982 SUPPLEMENT TO THE 1980-81 GEOTECHNICAL REPORT VOLUME 1 TEXT DECEMBER 1982 ...__ __ ALASKA POWER AUTHORITY __ ____,j I I I I I I I I I I I I I I • I I I I I ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT 1982 SUPPLEMENT TO THE 1980-81 GEOTECHNICAL REPORT TABLE OF GONTENTS -VOLUME 1 LIST OF TABLES LIST OF FIGURES Page 1 -INTRODUCTION ·······•o••o••······?·········~···&·········· 1-1 1.1 -·Genera"l ••••••••••••••• ,. .............................. 1-1 1.2 -Project Description and Location t••••·············· 1-l 1.3-Plan of Study ••o••···········~·····~~··············· 1-2 1. 4 -.leport Content ......................... ., • • • • • • • • • • • • • 1-3 1. 5 -Acknowl edgen1ents • • • .. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 1-3 2 -SUMMARY AND CONCLUSF'.,'S ................................ ~.H 2-1 2.1-Watdna Site·················~······~··············· 2-1 2. 2 -D ev i 1 Canyon S i t e : , • • • • • • • • • • • • • ~ • • • • • • • • • • • .. • • • • • • 2 -3 3 -SCOPE OF GEOTECHNICAL INVESTIGATION • • .. • • • • • • • .. • • .. • • • • • • • 3-1 3.1 -Introduction ............... ~ 9 ••••••••••••••••••••• ~, 3-1 3.2-Geologic Mapping ...................... ., ••••••••••••• 3-2 3.3 -Subsurface Investigations ••••••••• ~ •••••••• ,........ 3-4 3.4-Seismic Refraction Surveys ········•oe••····· .. ····· 3-5 3.5 -Laboratory Testing •••••••••o••; •••••••••••• , ••••••• 3-6 3.6-Borehole Instrunentation ............................. 3-6 4 -WATANA AREA GEOLOGY • • .. • • • • • • • • • • • • • • • .. • • • • • • • • • • • .. • • • • • • 4-1 4.1-Introduction ......................................... 4-1 4. 2 -Overburden and Topography • • • • • .. • • • • • • • • • • • • • • • • • • .. 4-1 4. 3 -Bedr·ock Stratigraphy ••••••••••••• , • • • • • • • .. .. • • • • .. • • • 4-1 4.4-Tectonic History ••••••••••••••••••••••••••••••••••• 4-2 4.5-Glacial History ..................................... 4-3 5 -RESULTS OF GEOTECHNICAL INVESTIGATIONS -WATANA DN~SITE •• 5-1 5.1 ·-Main Dam Foundation •• ,. •• •• • • •• .... •• • • •• •• •••••• •• • • 5-l 5.2 -Upstream Cofferdan and Diversion Portal Location • • • 5-18 5. 3 -Downstream Cofferdam and Portals Location ... • • • • • • • • 5-27 5.4-Spillway and Intake Areas ·······•oe••·············· 5-36 5.5-Aneilliary Civil Structures Location ................. 5-38 5.6 -Ground Water Regime •••••••••••••••• o ................. 5-39 5 .. 7 -Permafrost Regime • • • • • • • • • • • • • • • • • • • • • • • • • • • •. • • • • • • 5-40 6 -RESULTS OF GEOTECHNICAL INVESTIGATIONS - WATANA RELICT CHANNEL •••••••••••• : •••••• ,., • • • • • .. • .. • • • • • • 6-1 6.1 -Introduction ······$···························o···· 6-1 6.2-Location and Configuration •••••••••••••• H .......... 6-2 6. 3 -Stratigraphy of the Watana Relict Channe 1/ Borrow SiteD ................ ~ •••••••••••••••••••••• ~ 6-2 6.4 -Geologic Hi story of the Waana Relict Channel/ Borrow SiteD •• , ......................... ., •••••.••••••• 6-7 6.5 -Ground Water Regime ~ •••••••• :. • • •• .. • • • • • • • ... • • .. • .. • 6-12 6. 6 -Permafrost Regime ................................. ,, .. • • 6-13 6. 7 -Engineering Impacts ............. (> .............. H. o... 6-13 i TABLE OF CONTENTS ( Cont • d) 7 -RESULTS OF GEOTECHNICAL INVESTIG~TIONS - FOG LAKES RELICT CHANNEL ·······~········~················ 7.1-Introduction ••.•••• ~ ............................... . 7.2-Location and Configuration ......................... . 7. 3 -Geo 1 ogy ............ ., ......... "' ..................... . 7.4-Engineering Impacts-~··················~···,.·····~· 8 -RESULTS OF GEOTECHNICAl. INVESTIGATIONS - BORROW AND ~UARRY SITES ··················~··········o··~· 8.1 •> Intr·oduction •.• " ............................. " ...... . 8.2-Quarry Sites .••••••••.• •· • • • • • • • • • • • • • • e • • •· • • • • • • • 8.3-Borrow SiteD··············~·········~············· 8. 4 -Borrow Sites E and I ••.•...•••••.• ~ ................ . 8.5 -Borrow Site H ····••c••••··························· ·g -RESULTS OF GEOTECHNICAL INVESTIGATIONS- ·Page 7-1 7-1 7-1 7-3 7-4 8-1 8-1 8-1 8-1 8-5 8-6 DEVIL CANYON DAMSITE •.•••.••••.••• , ........................ 9-1 9.1-Introduction ··~···································· 9-1 9.2 -Material Properties ·····················~••o•w••••• 9-1 9.3 -Ground Water ............. ,... •• •. .. ••. .• •• •. ••• .••.. 9-3 9.4-Permafrost ....................................... , ...... 9-3 REFERENCES i i I~ I I I I I I I I I I I I I I I I I I • • I I I I I I I I I I I •• I I I I I I ALASKA POWER AUTHORITY SUSITNA HYDqOELECTRIC PROJECT 1982 SUPPLEMENT TO THE 1980·-81 GEOTECHNICAL REPORT TABLE OF CONTENTS -VOLUME 2 APPENDIX A -WATANA RELICT CHANNEL/BORROW SITE D -DRILLING LOGS APPENDIX B -WATANA RELICT CHANNEL/BORROW SITE D -LABORATORY TEST DATA APPENDIX C -SEISMIC REFRACTION SdRVEYS, SUMMER 1982 iii LIST OF TABLES Table Number Title 1.1 3.1 3.2 3.3 3. t.; 3.5 4.1 5.1 '" 5.2 5.3 5.4 6.1 6.2 6.3 8.1 8.2 8.3 9.1 9.2 9.3 9~4 Changes and Modifications to the 1980-81 Geotechnical Report Tables and Figures Watana Relict Channel/Borrow 5ite D -Summary of Investigations Watana Relict Channel/Borrow SiteD -Summary of 1982 Drilling Program Watana Damsite Vicin.: v -Summary of 1982 Seismic Refraction Surveys Watana Relic.t Channel/Borrow SiteD -Summary of Laboratory Testing Watana Relict Channel/Borrow Site D --Summary of Laboratory Testing Geologic Time Scale Watana Damsite and Vicinity -Seismic Velocity Correlations Watana Damsite -Joint Characteristics Watana Damsite -Upstream Cofferdam and Portal Area Joint Characteristics Watana Damsite -Downstream Cofferdam and Portal Area Joint Characteristics Watana Relict Channel/Borrow Site D Interpreted Depths to Top of Stratigraphic Units and Borings Watana Relict Ch&nnel/Borrow Site 0 -Interpreted Stratigraphic Unit Thickness in Borings Watana Relict Channel/Borrow SiteD -Borehol2 Permeability Test Results Watana Borrow Materials -Freeze-Thaw Durability Test Data Watana Sorrow Site E -Aggregate Suitability Test Data Watana Borrow Site E -Potential Reactivity of Aggregate -Test Data Devil Canyon Borrow Site G -Aggregate Suitability - Test Data Devil Canyon Borr0w t1aterials-Freeze-Thaw Durability Test Data Devii Canyon Borrow Materials -Potential Reactivity of Aggregc;1te -Test Data Devil Canyon Borrow Slte G -Estimated Borrow Material Availability iv I I I I I I I I I I I I I I I I [ijl I I I I I I I I I I I I I I I I I I I I ~ LIST OF FIGURES Figure No. 1.1 1.2 . 1.3 1 .. 4 3.1 3.2 3.3 3.4 4.1 5.1 5.2 5o3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 5.12 5.13 5.14 5.15 5.16 5.17 5.1,<3 5.19 5.20 5.21 6.1 6.2 6,.3 Title Location Map Watana General Arrangement Watana Dam General Arrangement Index of Figures · Watana Darnsite Exploration Map Watana Relict Channel/Borrow SiteD Exploration Map Wa.tana-Fog Lakes Relict Channel Exploration f1ap Typical Instrumentation Installation Details Watana Damsite Area Geologic Map Watana Oamsite Top of Bedrock and Surficial Geologic Map Watana Oamsite Geolo~ic Map Watana Damsite Geologic Section W-1 ~atana Oamsite Geologic Section W-2 Wa~ _.ta Oamsite Geologic Section W-3 Watana Oarnsite Geologic Section W-4 Watana Damsite Geologic Section W-5 Watana Damsite Composite Joint Plots Watana Damsite Typical Shear Watana Oarnsite Shear/Alteration Zone -11 The Fins•• Area Watana Damsite Geologic Features Downstream of Centerline Watana Damsite Upstream Cofferdam and Portal Area Geologic Map Watana Damsite Upstream Cofferdam and Diversion Portal Area Geologic Sections Watana Damsite Aerial View of Upstream Portal Area Watana Oamsite Photomosaic of Upstream Portal Area Watana Damsite Downstream Cofferdam and Portal Area Geologic Map Watana Damsite Downstream Cofferdam and Portal Area Geologic S~ctions Watana Damsite "Fingerbuster .. Area -North Bank c Watana Damsite Typical Shear/Fracture Zone - 11 Fi ngerbuster 11 Area Watana Damsite Geologic Feature GF 7J -"Fingerbustern Area W2tana Damsite Thermistor Data Wa-cana Relict Channel/Borrow Site D Surfici a1 Geologic Map Watana Relict Channel and Borrow SiteD Area Generalized Stratigraphic Column Watana Borrow Site D/Re'l ict Channel Stratigraphic Panel Diagram v LIST OF FIGURE~ (Cont'd) Figure No .. 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 7.1 8.,1 8.2 8.3 8.4 8 .. 6 8.7 8.8 8.9 8 .. 10 8 .. 11 8.12 8.13 8.14 8.15 8.16 Title Watana Relict Channel/Borrow SiteD Cross Sections \~atana Relict Channel/Borrow SiteD Typical Material Photos Watana Borrow SiteD/Relict Channel Stratigraphic Count ours Watana Relict Cnannel/Borrow SiteD Top of Bedrock Map Watana Relict Channel/Borrow SiteD Typical Gradation Curves Watana R~lict Channel/Borrow Site D Composite Drive Sample Blow Count Data Watana Relict Channel/Borrow SiteD Drive Sample Blow Count Data Watana Relict Channel/Borrow SiteD Thermistor Data Watana -Fog Lakes Re 1 i ct Channe 1 Top of Bedrock Hap Watana Borrow Site Map Watana Borrow Site D Isopach Map of Anticipated Borrow Material Watana Borrow Site D Composite Stratigr·aphic Unit Gradations Watana Relict Cham~el/Borrow SiteD Composite Natural Moisture Data Watana Borrow Stte-D Borrow Material Moisture/Gradation Relationship Watana Borrow Site D Borrow Mat,2ri a 1 Moisture Frequency Distribution Range and Means of Atterberg Limits Atterber g Limits Tests-Stratigraphic Units Above Unit E Atterberg Limits Tests -Stratigraphic Units E and F Atterberg Limits Tests -COE 11 AP 11 Series Auger Probes (1978) Atterberg Limits Tests -Stratigraphic Units Below Borrow Materials Watana Borrow Site D Range of Stanctard Proctor Density Tests -Stratigraphic Units C through F Watana Borrow Site D Standard Procter Oensit,v Test -COE Composite Sample (1978) Watana Borrow Site D Standard Proctor Density Tests - Selected Sandy Samp'les Watana Borrow Site D Standard Proctor Density Tests - Stratigraphic .Units E & F Watana Borrow Site D Modified Proctor Density Tests - Stratigraphic Units E & f vi I I I I I I I I I I I I I I ·I I I I I I I I I I I .I I I I I I I I I I I I I LIST OF FIGURES (Cont'd) Figure f\!J. 8.17 8.,18 8.19 8.20 8.21 9.1 9.2 9"3 Title Watana Borrow Site D Modified Proctor Density Test - Stratigraphic Unit G Watana Borrow Site E Geologic and Exploration Map vJatana Borrow Site I Geologic and Exploration Map Watana Borrow Site E Aggregate Reactivity Test Data Watana Borrow Site H Thermistor Data Devil Ganyon Borrow Site G Aggregate Reactivity Test Data Devil Canyon Damsite General Arrangement and Instrumentation Location Map Devil Canyon Damsite Thermistor Data vii I I I I I I I I I I I I I I I I I I 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 (Figtire 1.1). The 1980-82 hydroelectric development feasibility studies Wf're 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 fe...;sibil ity 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 Hydroe 1 ectri c Project; and -To file a license application with the Federal Energy Regulatory Commission (FERC) should the project be deemed feasible. As part of the Plan of Study (rOS), a geotechnical exploration program (Task 5) wa;;. undertaken at the proposed damsite locations of \>Jatana and Devil Canyon, and along the access and transmission corridors. Results of the 1980-81 exploration program were presented in the 1980-81 GeQ- technical Report submitted to The Power Authority in March 1982(1}. Since the submittal of that report, l.!dditional geotechnical work was performed during the summer/fall of 1982. The purpose of this report is to provide a supplement to the 1980-81 Geotechnical Report. The work performed in 1982 was diretted at augmenting and further defining specific site geologic and geotechnical conditions at the vlatana and Devil Canyon sitese Therefore, some of the information and data pre- sented in the previous report has been superseded by this supp 1 ementa 1 report.. Specific sections, figures, and tab 1 es that have been super- ceded have been so denoted in Table 1.1. This·report has been written with the inte~t of providing a fully com- prehensive understanding of the major subjects addressed in the 1982 work without continued reference to t:he 1980-81 report. However, to get a full understanding of the site geotechnical conditions at Watana and Devil Canyon, both documents will be required .. 1.2 -Project Description and Location The Watana and Devil Canyon sites had been previously studied by the U.S. Bureau of Reclamation (USBR) and the U.S. Army Corps of Engineers (COE) over a period of years from 1952 to 1979. 1-1 The current feasibility scheme calls for a large-embankment dam with an underground powerhouse at Watana, and a high concrete arch dam with underground powerhouse at the Devil Canyon site. General site arrange- ments for Watana are shown in Fi~ures 1.2 and 1.3. The general arran- gement drawing for Devil Canyoti is included as part of Figure 9.2, and is presented in more comprehensive deta i 1 in the 1980-81 Geotechni ca 1· Report. The area of study is 1 ocated within the Coastal Trough Pro vi nee of south-central Alaska, with a drainage of appr·oximately 6,000 square miles. The. Susitna River is glacier-fed, ·with headwaters on the southern s1 ope of the Alaska Range. From its progl aci al channel in the Alaska Range, the Susitna River passes first through a broad, glacia- ted, intermontane valley of knob and kettle, and braided channel topo- graphy. Swinging westward along the edge of the Copper River low1ands1 it enters the defo valleys which include the proposed damsites, winding through the Talkeetna Mountains until it emerges into a broad glacial outwash valley leading to Cook Inlet near Anchorage. The ~,'atana site is located at approximately river mi'ie 184 between Ts~sena and Deadman Creeks. The Watanaadamsite is located ir a rela- tively broad U·-shaped valley rising in steps, \"-lith steep lower portion breaking into somewhat fl-attr=r slopes and becoming much gentler near the top. Access to the lower sections is limited by vertical rock out- crops. Gravel bars, some of which are quite wide, are expo~ed in the river bed during low water flows. The river at this site is approxi- mately 500 feet wide and is relatively turbulent and &wift flowing. The Devi 1 Canyon site occupie~. a_ very narrow bedrock gorge at approxi- mately river mile 152. 1.3 -Plan nf Study (a) Objectives As detailed in the 1980-81 Geotechnical Report, the objectives of the geotechnical program were to determine the surface and subsur- face geology and geotechnica1 conditions for the feasibility of: - A 1 arge rockfi 1'1 dam, underground powerhouse, and associated structures at Watana site; - A concrete dam with underground powerhouse and associated struc- tures at Devil Canyon site; -Tr'ansmi ssi on 1 i ne to connect the proposed de vel opme,lt with the existing power grid system; and -Access roads to the proposed developmento (b) Scope To accomplish these objectives, Acres undertook eight subtasks ranging from Data Collection and Review through the exploration programs to data compilation and report preparation. •> 1-2 I I I I I I I I I I I I I I I I I I I •• I I I I I I I I I I I I I I I I I I As a result of that work, additional areas at the Hatana site were considered to warrant the further studies which were undertaken during the summer of 1982. Those areas were the: -Watana Relict Channel; -Fog Lakes Relict Channel; -Borrow Site D; -Dams i te Geo 1 ogy, with specific attention to the upstream di vet"- sion portal and downstream portal areas. This work was undertaken in a tr:Ulti-disciplinary approach using personnel experienced in geology, rock mechanics, and geotechnical engineering .. Due to cost, scheduling, and logistical constraints, the scope of the 1982 program was designed to provide additional information tn these particular areas, which would be used for developing a more comprehensive geotechni ca 1 program (1983:-1985). Thet~efore, this report ser·ves as an interim progress report to be updated . as ongoing work proceeds. 1.4 -Report Content This supplemental report is presented in nine sections: summary and the conclusions of the study in Section 2; detailed scope of geotechni- cal investigations in Section 3; geology of the Watana area in Section 4; results of the geotechnical investigations at the Watana damsite in Section 5; Watana Relict Channel in Section 6; Fog Lakes Relict Channel in Section 7; Watana Quarry and Borrow Sites in Section 8; and Devil Canyon damsite in Section 9. An ·ndex map showing the locations of maps used in this report is shown on Figure 1.4. Appended to the report are the 1982 dr i 11 i ng logs, 1 abm~atory test data, and seismic refraction surveys report. Engineering significa11,ce and applications of the data d_eveloped from the ge;otechnical program are presented in the Susitna Feasibility Reportt2J and the Supplement to the Susitna Feasibility Report (3).. This document, therefore, stands as a referenced docu- ment in those reports. 1.5 -Acknowledgements Drilling at the site was performed by Denali Drilling, Incorporated, Anchorage, under the direct supervision and direction of Acres American personnel. Seismic refraction surveys for 1982 were performed by Woodward-Clyde Consultants. Survey control and brushing, instrumenta- tion reading, and assistance in the onsite laboratory was provided by R&M Consultants~~ logistical support was provided by Air Logistics, Inc., under subcon- tract to Acres. 1-3 The results of the 1982 activities were pre.sented to Dr. Peck of the Acres External Panel and Dr. H. Seed and Dr. A. Merritt of The Power Authority's Panel in November, 1982. Acres is gr'ateful for their comments and critical review of the information. 1··4 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I TABLE 1.1: CHANGES AND MODIFICATIONS TO THE 1980-81 GEO'r ECHNICAL REPORT TABLES AND FIGURES 1980-81 1982 Table Table No. No. Subject (1980-81 Report) 3.1 3.2 3.3 3 .. 4 3.5 4.1 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5 .. 10 6.1 6.,2 (3) (3) (3) {3) (3) 4.1 {3) {3) (3) (3) (3) (3) (3) (3) 551 5.2, 5.3, 5.4 *Summary of i)revious Investigations -~Jatana Damsite *Summary of Previous Investigations -Borrow Site D - Watana , *Summary of Previous Investigations -Borrow Sites E, F, and C -Watana *Summary of Previous Investigations -Devil Canyon Damsite *Summary of Previous Investigations -Borrow Site G - Devil Canyon Geologic Time Scale *Summary of the 1980-81 Investigation -Watana Damsite *Summary of the 1980-81 Inyestigation -D2vil Canyon Damsite *Summary of the 1980-81 Seismic Refraction Line Data *Summary of 1980-81 Investigation -Borrow Site D - \~at ana *Summary of 1980-81 Investigation -Borrow Site E - Watana *Summary of 1980-81 Investigation -Borrow Site G - Devil Canyon *Summary of 1980-81 Investigation -Borrow Site H Watana *Summary of 1980-81 Investigation -Borrow Sites I and J -Watana Summary of Rock Tests -Wa~ana Summary of Rock Tests -Devil Canyon *Watana Seismir u,,'1city Correlations *Watana Joint Characteristics 6e3 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 Por ;.thyry 6.7 Figure 6.2 *Quaternary Stratigraphy of Buried Channel Area 6.8 Figures Material Properties-Borrow Site 0 8.4-8.17, Appendix B 6.9 Figs5, 8.3, *Gradation Results-Borrow SiteD 8.7 6.10 8.1, 8.3 Material Properties -Borrow Site E 6.11 Material Properties -Borrow Site H {1) *1980-81 TJble/Figure is either superceded ii. entirety by Supplemental Report Table/Figure; or 1982 Table/Figure is supplementary to 1980-81 Table/Figure. (2) No 1982 listing means 1980-81 Table/Figure remains unchanged. (3) Summarized i·! project. survey and instrumentation data files. I I l I I I' I 1980-81 Table No. 6.12 7.1 7.2 7.3 1982 Table No TABLE 1.1 (Cont'd) Subject (1980-81 Report) Material Properties -Borrow Sites I and J Devil Canyon Seismic Velocity Correlations Devi 1 eanyon Joint Characteristics Devil Canyon Tail race-Tu nne 1 -Joint Characteristics Devi1 Canyon RQD Summary . ·, -·: .... '..-.... ·. • .. ~ -d . ' r• • . -4'-t -. .. ' ' ~ ~ .... . ' . . . . . 7.4 7 .. 5 7.6 Devil Canyon -Borehole Rock Quality Distribution Devil Canyon Rock Test Summary -Mafic Dikes and 7 .. 7 7. 8 Figure 9. 1, Tables 9.1-9.3 Argi 11 ite Devil Canyon Rock Test Summary -Graywacke Material Properties -Borrow Site G (1) *1980-81 Table/Figure is either superceded in entirety by Supplemental Report Table/Figure, or 1982 Table/Figure is supplementary to 1980-81 Table/Figure. (2) No 1982 listing means 1980-81 Table/Figure remains unchanged. (3) Summarized in project survey and instrumentation data files. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I. I 1980-81 Figure No. -- 1 .. 1 1 .. 2 1.3 4.1 5.1a 5.lb 5 .. 2 5.3 5.4 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 6.12 6.13 6.14 6.15 6.16 6.17 6.18 6.19 6.20 6.21 6.22 6.23 6.24 6.25 6.26 6.27 6.28 6.29 6.30 1982 Figure No 1.1 1.2, 1.3 9.2 4.1 3.2 3.1 3.4 1.4 5.1 5.1, 5.12, 5.16 5.3, 5 .. 13 5 .. 4 5.5, 5.17 5.6 5. 7 5 .. 8 5.9 5 .. 10 5.14, 5.15 5 .. 11 5.18, 5.19 5.20 5.21 6.11 6.11, 8.21 6.5 TABLE 1.1 (Cont'd) Subject {1980-81 Report) General Location Map *\~atana General Arrangement *Devil Canyon General Arrangement *Regional Geology Map *~-Jatana: Damsite Vicinity Exploration t~ap *Watana: Exp 1 or· at ion Hap Devil Canyon Exploration Map Borehole Typical Instrumentation Borehole Typical Instrumentation Watana Index Map *Watana Top of Bedrock and Surficial Geologic Map *Watana Geo1ogic Map *Watana Geologic Section W-1 *Watana Geologic Section W-2 *Watana Geologic Section W-3 *Watana Geologic Section W-4 *Watana Geologic Section W-5 Watana Andesite Porphyry Flow Structure and Inclusions \~at ana Fracture. Zone in Andesite Porphyry Watana Felsic Dike in Diorite Watana Joint Station Plots *\~at ana Composite Joint Plots *Watana Typical Shear *Watana Shear/Alteration Zone \oJatana 11 The Fins" Watana Geolos~ic Features GF4A, GF4B, and GF5 *Watana Geologic Features Downstream of Centerline *vlatana ''Fi ngerbuster" Area North Bank *Watana Geologic Feature GF7B Watana Rock Tests Watana Static Elastic Properties for.Andesite and Diorite Watana Direct Shear Tests Watana Unconfined Compressive Strength Test Results Watana Point Load Test Data Watana Rock Permeability *Watana Thermistor Data *Watana Thermistor Data-Relict Channel *Watana Therreistor Data -Borrow Site D and Borrow Site H Watana Relict Channel Photos (1) * 1980-81 Table/Figure is· either superceded in entirety by Supplemental Report Table/Figure, or 1982 Table/Figure is supplementary to 1980-81 Table/Figlre. (2} No 1982 listing means 1980-81 Taoie/Figure remains unchanged. 1980-81 1982 Figure Figure No. No. 6 .. 31 6. 4' 6. 6 6.32 6.1' 6 .. 2' 6.3 6.33 6.4 6.34 6.35 6.7 6.36 8.1 6.37 611t38 6.39 6.40 8.2 6.41 8 .. 3 6.42 6.8 6.43 8.18 6.44 6.45 6.46 6.47 6.48 6.49 6.50 6.51 8.19 6.52 6.53 6.54 7 .. 1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 7o 10 Table 1.1 (Cont'd) Subject (1980-81 Report) *'~atana Relict Channel Section xwatana Relict Channel and Borrow Site D/ Stratigraphic Fence Diagram *Watana Relict Channel -Expanded Thalweg Section Watana Relict Channel Profiles *Relict Channel -Top of Bedrock *Watana Borrow Sites Index Map WatanJ. Qt:. J.rry 3i te A -Plan and Sections Quar·ry Site B -'plan and Sections Borrow Sites C ~~d F Bor-row Site D -P1 an *·watana Borrow Site D -Ranae of Gradations oJ hatan~ Borrow Site D -Material Gradation Types Borrow Site E -Plan Borrow Site E -Sections Watana Borrow Site E -Range of Gradations Watana Borrow Site E -Stratigraphic Unit Gradations Borr6w Site C and F -Range of Gradations Borrow Site H -Plan Watana Borrow Site H -Range of Gradations Watana Borrow Site H -Stratigraphic Unit Gradations Borrow Site I -Plan Borrow Site J·-Plan Borrow Sites E, I, and J -Photos and Typical Sections Quarry Site L -Plan and Sections De vi 1 Canyon Index Map Devil Canyon Top of Bedrock and Surficial Geologic Map Devil Canyon Geo 1 ogi c Map Geologic Sections DC-1 Geologic Sections DC-2 Geo 1 ogi c Sections OC-3 Geologic Sections DC-4 Geologic Sections DC~5 Geologic Sections DC-6 Ge0logic Sections DC-7 (1) * 1980-81 Table/Figure is either superceded in entirety by Supplemental Report Table/Figure, or 1982 Table/Figure is supplementary to 1980-81 Table/Figure. (2) No 1932 listing means 1980-·B1 Table/Figure remains unchanged. I I I I I I I I I I I I I I ~ I I I I I I I •• I I I - I I I I I I I I I I I 1980-81 Figure No. 7.11 7.12 7 .. 13 7.14 7.15 7.16 7.17 7.18 7.19 7.20 7.21 7.22 7,23 7.24 ·.25 7.26 Table 1.1 (Cont'd) 1982 Figure No. Subject (1980-81 ~eport) De vi 1 Canyon Typi ca 1 Argi 11 ite/Graywacke Devil Canyon Aerial View of Site Devil Canyon Joint Plots Devil Canyon Tailrace Geology Devil Canyon Rock Tests Devil Canyon Static Elastic Properties for Argillite and Graywacke De vi 1 Canyon Direct Shear Tests Devil Canyon Unconfined Compressive Str~ngth Test Results Devil Canyon Point Load Test Data Rock Permeability 9.3 *Thermistor Plots ~ Damsite Borrow Site G -Plan Borrow Site G -Sections De vi 1 Canyon Borrow Site G -Range of Gradations Devi 1 Canyon Borrow Site G -Stratigraphic Unit Gradations Devil Canyon -Quarry Site K (1) * 1980-81 Table/Figure is either superceded in entirety by Supplemental Report Table/Figure, or 1982 Table/Figure is supplementary to 1980-81 Table/Figu~e. (2} No 1982 listin~ means 1980-81 Tab12/Figure remains unchanged. I I I I I I I I I I I I I I I I - I I ~ ' ~ ·~ J LOC..ATION MAP LEGEND \I PROPOSED DAM SITES ~ ~ LOCATION fv1AP FIGURE I I I I I I I I I I .I I I I I • • N3.228.000 N3,232,000 N3,?34,000 ~'-"---- N 3,2.38.000 "' ol [ g ~ §: 1'-;tl u) "'T "' w w! w -- if; WATANA GENERAL ARRANGEMENT BORROW SITE E FILTER a SOURCE AGGREGATE SCALEO !!' !!!!!~I~O~OO;.~Z~OOO FEET FIGURE 1.2 I IACIII I I I -- i I I N 3,226,000 I I I I N3,227,000 - I I I I I / I , INTAkE __ / :· AP . ' ·-· -PROACH CHANNEL I N3,t29,000 I 00 <V . .., 4 ·• \ ~ 0 ¢-'? OUTLET INTAKE PENSTOCKS- ACCESS . ...., - ·---~------- r-CREST OF EL. 2210 DAM ~ __,r-- __./. . \ ~ now~ C~FFEROAM . --POWeRHOUSE SPILLWAY FUf> OUTLET FAClLJyOCKf 'i AND DISCHARGE VALVES 0 200 SCALE ~~~5iiiiiiiiiiiii~400 FEET I I I I I I I I I I I I I I I I I ·' f '----.. .~ ~-··---·~- S\JS!TNA RIVEP. '' \ \ INDEX OF FIGURES SCALE 0~~~45i;;;;;;;;;:;o:ii00ii8 Mite LOCATION MAP BLOCK AREA COVERED * FIGURE NO. SCALE REFERENCE GENERAL ARRANGEMENT 1"•,2500' FIGURE 1.2 tj\ DAMSITE VICINITY• STRATIGRA?MIC UNIT MAPS I"= 2500' FIGURE 6.6 \..!..· TOP OF BEDROCK ,. ,. 2500' FIGURE 6.7 BORROW MATERIAL JSOPACHS ,. "'2500' FIGURE 8.2 GENERAL ARRANGEMENT ! •• 500' FIGURE 1.3 ® EXPLORATI.ONS t•"' 500' FIGURE 3.1 "'AMSI'fE• SURFICIAL GEOLOGY AND , •• 500' TOP OF BEDROCK FIGURE 5.1 ® GEOLOGIC MAP , •• 500' FIGURE 5.2 PORTAL AREAS• GEOLOGIC MAPS , •• 1001 FIGUR£: 5.12,5.16 @ RELICT CHANNEL/BORROW SITE D• EXPLORATIONS I"= 1000' FH'iURE 3.2 GEOLOGIC MAP I"= 1000' FIGURE 6.1 IM FOG LAKES RELICT CHANNEL• EXPLORATIONS l": 5000' FIGURE 3.3 ~--TOP OF BEDROCK 1°" 50001 FIGURE 7.1 (4)a~ WATANA AREA • GEOLOGIC MAP I"= 5ooo' FIGURE 4.1 ~ BORROW SITE E;. GEOLOGY AND EXPLORATIONS I"= 1000' FIGURE 8.18 \7 BORROW SITE I GEOLOGY AND EXPLORATION$ I"• 2500' FIGURE 8.19 -.;.. ·lf REDUCED n•,_ i7" REPORT FORMAT 0 1 2 MILES SCALE: e.~ ·-~ FIGURE 1.4 I I I I I I I I I I I I I I I I I • I I 2 -SUMMARY AND CONCLUSION The following subsection presents the findings and conclusions of the 1982 geotechnical work. These conclusions supplement and/or supersede those conclusions set forth in the 1980-81 Geotechnical Report (1). Unless specifically addressed below, the study results and conclusions presented on Reference 1 remain unchanged. 2.1 -Watana Site (a) Results of Study Work performed in 1982 showed that overburden on the dam abut- ments is generally shallow, seldom exceeding 30 feet~ with talus slopes and alluvium-filled gullies locally having 50 to possibly as much as 100 feet of overburden. -Two types of alluvium have been identified in the damsite; Type 1, principally below water level, is sandy gravel, well graded with fine gravel to boulders; and Type 2, occurring principally on the south bank above river level, is a well graded sandy gra- vel .with fragments ranging up to 2 feet but generally 4 to 6 inches. Two types of t~lus were identified in the damsite, Type 1 is primarily well exposed actively moving material, 'VIhile Type 2 is generally heavily vegetated inactive material. - A northwest trending hydrotherma_lly altered zone up to 400 feet wide has been map~ed on the south bank predominately downstream of the main dam centerline. Small shears3 fracture zones and alteration zones were mapped in the damsite. These features generally parallel joint sets I, II and I I I. -No evidence of recent faulting was found at the damsite. -Drilling and seismic refraction surveys performed in the vJatana Relict Channel confirmed that the exposed face at the entrance to the channel, along the north re~ervoir rim is on the order of 18,000 feet wide. The approximate channel width at the bedrock saddle dividing the Susitna River and Tsusena Creek (under maxi- mum normal operating level of Elevation 2185) is about 15,000 feet with a maximum depth of 420 feet.. Average hydraulic gra- dient from maximum ?OOl level to Tsusena Creek is 9 percent. -Overburden stratigraphy of the Watana Relict Channel/Borrow Site D has been modified and expanded from that determined during the 1981 i nvesti gati ons. Fourteen stratigraphic units have been classified in the area, based on mode of deposition. Modifica- tions to the 1980-81 interpretation include the classification of Unit C as an ice disintegration deposit; breakdown of Unit G 2-1 ' ~~~l~ I into waterlain and basal till facies (Units G and G'); reclassi- fication of Unit I as an outwash; reinterpretation of Unit H as being discontinuous and of variable grain size; and identifica- tion of an add-itional basal till found in the southeastern por- tion of Borrow Site 0, designated Unit M. Other findings of the 1982 drilling program confirmed previous interpretations of the stratigraphy, with local modifications. -The ground water regime in the Watana Relict Channel/Borrow Site 0 is a combination of perched, artesian and possible confined conditions. Preliminary ev al uati on suggest that the more per- meable stratigraphic units are discontinuous. -Permafrost in the Watana Relict Channel/Borrow SiteD is spora- dic with no evidence of extensive iLe lenses or ice cr·ystal s. Thermistor data show most temperatures to range between -0. 5°C and +0.5°C. -Material densities, as determined by Standard Penetration Tests (SPT), are high for the relict channel material. -Bedrock surface drop; below maximum pool elevation at the Fog Lakes Re1 ict Channel for appt-oximately 8000 feet from 0. 5 to 10 miles upstr-eam of the damsite. Maximum depth at the Fog La~<es Relict Channel is approximately 250 feet below pool elevation .. Maximum hydraulic gradient for pool level to Fog Creek is appro- ximately 0 .. 3 percent over a distance of 4 to 5 miles. -Although no borings were drilled in the Fog Lakes Relict Chan- nel, the material, based on, seismic velocities, are assumed to be dense tills and glacio-fluvial deposits with significant areas of permafrost. (b) Conclusions Based on the work performed in 1982, the following conclusions re- garding .the vJatana Site can b-: made: -No geologic or geotechnical conditions were found to affect the feasibility of an embankment dam at the site. -Rock conditions in the area of 11 The Fi~s" appear to be rna, ... ~ severe than previvusly suspected in 1980-81. Cond~tions of joints and fractures in this area will have to be catefu11y eval.Jated in designing rock cuts and support for upstream diver- sion tunnel portals. -No adverse geologic or geotechnical conditions were found that would impact on engineering design criteria set forth in the Susitna Feasibility Report (2). 2-2 I I I I I I I I I I I I I I I I I I I I I I I I I I I •• I I I . I I I I I I I -Although additional work remains to be done in the Watana Relict Channel to assess potential problems of piping and breaching of the reservoir by settlement or 1 iquefaction, work performed dur- ing 1982 provided strong evidence that in the upper 200 to 250 feet of the channel, remedial work ma.y not be required. - -At this time, no leakage or liquefaction ri~K is seen in the Fog Lakes Relict Channel. -The sporadic permafrost found in ~rrow Site D does not appear to cause problems in the developnent of the borrow site. -Aggregate and freeze-thaw testing confirmed ~he suitability of quarry and borrow material for construction. -While adequate bor·row materials are readily available, the de- velopnent of Borrow Site D will be. controlled by the moisture criteria fv. core material. 2.2-Devil Canycn ( aj Results of Study -Groundwater and temperature data collected during 1982 confirm previous 1980-81 data • -Concrete aggregate tests perfo'."med on Borrow Site G material confirmed suitability of material fm .. construction. · -Freeze-thaw testing of Quarry Site K showed questionable dur- ab i 1 it y res u 1 t s • (b) Conclusions -No geologic or geotechnical conditions were found during 1982 to adversely affect the Devil Canyon development as presented in the Susitna Feasibility Report (2) • -Although Borrow Site G material was found suitable for construc- tion, test results were variable based on location of samples. Further detai 1 ed testing in this area will be required. -Freeze-tha\\ tests on Quarry Site K material are questionable, suggesting that the samples from K may have been disturbed prior to testing. Additional testing will be required .. 2-3 I I I I I I I I I I I I I I I I I I I 3 -SCOPE OF GEOTECHNICAL INVESTIGATIONS 3.1 -Introduction Studies performed during the 1980-81 program raised a number of ques- tions regarding the Watana Damsite area, the Watana Relict Channel, Borrow SiteD, and the Fog Lakes Relict Channel* During the summer of 1982, Acres initiated additional geotechnical investigations to supplement those carried out during the 1980-81 investigations. These investigations v1ere undertaken at the Watana site from July through September, 1982 .. Spec1fic areas requiring additional studies were: Watana Damsite o extent of mapped geo 1 ogi c features to inc 1 ude shears, a 1 terat ion and fracture zones; • bedrock conditions in the upstream and downstream portal areas; • geology of 11 The Fins" and 11 Fingerbuster 11 shear .eones; -Watana Relict Channel e channel geometry; • stratigraphy; • continuity of st~atigraphic sequence; • material properties; • ground water; • permafrost; -Borrow Site D • material properties; • stratigraphy; o material quantities; • ground water; .. permafrost; -Fog Lakes Relict Channel • channel geometry; • stratigraphy; • grounct water • permafrost; To answer these areas of concern, Acres undertook a limited geotechni- cal program th~t involved exploratory drilling, field mapping, seismic refraction surveys, laboratory testing and installation instrumenta- tion. This section discusses the scope of these investigationso 3-1 3.2 -Geologic Mapping (a) Introduction (b) '"·' The Acres geologic mapping program for the Susitna Hydroelectric Project was undertaken to define the 1 i tho 1 ogy and structure of the area for the proposed damsites. The mapping program has been performed in four phases: Summer 1980, Winter 1980-81, Summer 1981, and Summer 1982. Results of the Summer 1982 mapping program are presented in this report. Previous mapping is discussed in the 1980-81 Geotechnical Report (1). The principal objectives of the 1982 program were to perform detailed and general mapping to: c -Refine existing geologic interpretations of the Watana damsite particularly with respect to civil structure arrangements. -Define the surficial sediments in the Watana Relict Channel/ Borrow Site D area. -Determine the extent of the Fog Lakes Relict Channel~ -Define the surficial geology of Borrow Sites E and I. -Establish a geologic model for the damsite area. Mapping during the 1982 Summer program was done during July, August and September by a team of two geologists. The geologic data collected consisted of identifying outcrops and noting size, orientation, lithology, weathering characteristics, jointing and other structures in the rock. All si gni fi cant features were photographed. Details of the results are presented in Sections 4) 5, and 7. Watana Area Regional geologic mapping was performed in a broad area surround- ing the Watana damsite to determine the extent of the diorite plu- ton underlying the site and its relation to the surrounding geolo- gic units. Mapping was done by airphoto interpretation, aerial reconnaissance and ground checking. Data was plotted on aeri a 1 photographs and 1 ater transferred to a topographic map. Botr photograph and map scales were 1 inch equal to 2,000 feet. The area covered during this program extended from approximately 11 miles east to 5.5 miles west of the Watana. damsite, a:-~d from 4.5 miles south to 3.5 miles north of the site. Mapping was con- centrated a 1 ong the major drainages: Susitna River, Fog Creek, Deadman Creek, Tsusena Creek, and Bear Creek which flows through Borrow Site E. Results of the Watana area mapping are presented in Sections 4 and 7. 3-2 I I. I •• I· I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I (c) Watana Damsite Geologic mapping in the damsite was divided into th ... following areas: upstream cofferdam and div~ 3ion portal area, downstream cofferdam and porta 1 area, and abutments~ For precision mapping in the porta 1 areas, a survey grid was established. Six survey contra 1 stations were estab 1 i shed in the upstream porta 1 s area and eight in the downstream portals area. Additional stations were established on both north and south abutments throughout the dams i te. Geo 1 ogi c mapping in the porta 1 areas was done by the 11 Tape and Brunton" method at a scale of 1 inch equ~al to 100 feet. Survey contra 1 points were used at beginning and end points of traverses, and also for triangulation where necessary. Closure of the traverses was within 10 feet. Mapping in the upstream crrea was done on the north bank to Elevation 1, 9'JO and on the south bank to about Elevation 1,600. Mapping of the downstream portal area was confined to the north bank up to Elevation 1,800, since the south bank was mapped in 1981. A seismic refraction survey was run in conjunction with the mapping program and is discussed in Sect ion 3. 4. These explorations. are shown on Fi gurc 3.1.. The full extent of shears, fracture zones and alteration zones were traversed where possible. Areas of loose and unstable rock were generally avoided for safety. Results of the damsite mapping are pt"esented in Section 5. Mapping of the abutments was done primari 1y on the north bank between the upstream portal area and approximately 300 feet down- stream of the proposed centerline location. The ~·rape and Brun- ton .. method was used here, with a mapping scale of 1 inch equal to 200 feet. Several previously mapped outcrops downstream of the dam center 1 i ne on the south bank were revisited during 1982 to confirm previous geologic interpretation. (d) \~atana Relict Channel /Borrow Site D Mapping in the Watana Re 1 i ct Channe 1 /Borrow Site D was done to define the stratigraphy of the sediments within the relict channel and to correlate units with those identified in the boreholes. Mapping was perfoY'med a 1 ong both banks of Ts usena and Deadman Creeks. Tsusena Creek was mapped from about 1.6 to 2.6 miles up- stream from its confluence with the Susitna River. Deadman Creek was mapped from the Susitna River to 1.6 miles upstream from the confluence. Mapping was done along the Susitna River from Deadman Creek downstream to the upstream· portal area. The surfi cia 1 de- posits of the Watana · Re 1 i ct Channe 1 area were a 1 so mapped from Deadman Creek to Tsusena Creek. Geologic mapping was performed initially by aerial reconnaissance followed by ground traverses. Outcrops were marked on 1 inch equal to 400 feet aerial photographs. Elevations were taken using an altimeter. Data was subsequently transferred to a topographic map of the same scale. Results of the Watana -Relict Channel/ Borrow Site D mapping ar~ pres.ented in Section 6. 3-3 (e) Fog Lakes Relict Channel Mapping of the Fog Lakes Re 1 i ct Channe 1 was performed to define the limits of the feature~ and the stratigraphy of the infilling materials. Geologic mapping was done initially by aerial recon- naissance, followed by ground checking. Data, which included out- crop elevations, was plotted on aerial photographs at a scale of 1 inch equal to 2,000 feet and transferred to a topographic map at the same scale. Mapping was done along the north and south banks of the Susitna River upstream from the Watana damsite area to beyond Watana Creek~ approximately 11 miles. This mapping was done in conjunction with the Watana Area mapping discussed in {b). Results of the Fog Lakes mapping ~re presented in Sections 4 and 7. (f) Borrow Sites E ana I Mapping of the surfi cia 1 geo 1 ogy in Borrow Sites E and I was per- formed primarily by airphoto interpretation, with limited ground checking and aerial reconnaissance. Geology t'/as mapped on air- photos at a scale of 1 inch equal to 2~000, feet and subsequently transferred to a topographic map at a sea 1 e of 1 inch equa,l to 1,000 feet. Mapping extended from about 1 mile upstreaP" of Borrow Site E to the previously defined downstream limit of Borrov1 Site I. Results of the Borrow Sites E and I mapping are presented in Section 8. 3.3 -Subsurface Investigations A subsurface i nvesti gat ion program was undertaken during the summer of 1982 in the Watana Relict Channel and Borrow Site 0. This program con- sisted of exploratory drilling, as well as field mapping and sampling of exposures in these areas. Investigations in Borrow Site 0 centered on obtaining additional .infor- mation on the stratigraphy of the area and on securing samples for laboratory characterization of borrow material properties. Watana Relict Channel investigations were aimed at refining the previously developed stratigraphy, determining leakage potential, and investigat- ing the nature of the overburden materials with respect to hydrogeolo- gy, permafrost, and liquefaction potential. A tot a 1 of 16 rotary borings~ numbered AH-015 through AH-030 were drilled in Borrow Site 0 and the Watana Relict Channel area using twa Mobile B-61 dri 11 rigs. In addition, 29 exposures were mapped and sampled. Drilling and sampling locations are shown on Figure 3.2, and are summarized on Table 3.1. Initially, holes were continuously drive sampled using a 3-inch-diameter, 2 foot lor split-spoon sampler driven with a 300 lb hammer. When sufficient St-ratigraphic data was devel- oped, sampling was expanded to 5 foot int~rvals and. at change~ in stra- ta or drilling conditions. 3-4 I I I I I I I I I I I I I I I I I I I I I I· I I I I I I I I I I I I I I I I Drilling was initially planned to use hollow stem augers. Due to difficult drilling conditions encountered in the first hole (AH-015), the method of dri 11 i ng was changed to rotary dri 11 i ng. Attempts were made to obtain undisturbed samples using 2 foot Shelby tubes as well as a 5 foot Dennison sampler. The extremely bouldery nature of several of the strata, however, prevented the successful recovery of undisturbed samples. All drilling was supervised by Acres drilling inspectors, and all field logs were prepared at the drill site. Overburden exposures, investiga- ted as part of the subsurface investigation, were logged in the field. Logs for drill hcles are presented in the Appendix A. A summary table of 1982 explorations; including borings and types of instrumentation installed is provided as Table 3.2. Test pit informa- tion has not needed corrections; however, survey data adjustments and borehole statistics additions and corrections have been made in nume- rous cases to the borehole data tables for previous explorations and are included in the project final survey data files. 3.4 -Seismic Refraction Surveys A tot a 1 of 92,439 linear feet of seismic refraction survey were run during September, 1982.. Seismic lines were run at; -Watana damsite Abutments: 21,373 linear feet; -Watana Relict Channel/Borrow Site 0: 26,018 linear feet; -Fog Lakes Relict Channel: 45,048 linear feet; Seismic refraction surveys were performed by Woodward-Clyde Consul- tants (WCC), and a summary of these investigations is indicated on Table 3.3. The details of the seismic refraction survey are provided in Appendix C. Seismic refraction surveys in the Watana damsi te area were undertaken to determine the amount of ove: burden present, characterize the bedrock surface, and to locate discont1nuities and bedrock velocity variations. A total of fifteen lines were run, sequentially numbere~ SL82-l through SL82-15. Locations of these lines were selected to supplemt:nt previous seismic work in the ar·ea, as well as to provide subsurface information in areas of the proposed civil structures. Locations of the damsite seismic lines are shown on Figure 3.1. Watana Re 1 i ct Channel/Borrow Site D seismic surveys were performed following those at the damsite. The purpose of these lines was prima- rily to provide supplemental information to further characterize the topography of the bedrock surface in the area, and to refine the inter- pretation of the Hat ana Re 1 i ct Channel geometry. Seven lines were run in the area, numbered SL82-16 through SL82-22 and are shown on Figure 3.2. 3-5 Seismi~ work in the Fog Lakes area was carried out to verify the exis- tence of a relict channel discovered during the 1980-81 investigations. Three long refraction lines were run in a direction anticipated to cross the tha 1 weg of th~ re 1 i ct channe 1. These 1 i nes are numbered SL82-FL1 _through SL82;FL3 and are shown on Figure 3. 3. Results of the seismic refraction survey are discussed in Sections 5, 6, 7, and 8 and the survey report is attached as Appendix c. 3.5 -Laboratory Testing (a) 1982 Field Testing A soi 1 s 1 aboratory was estab 1 i shed on site to support the fie 1 d program. Samples were shipped dai1y from the drill rigs to the 1 aboratory for immediate testing. A total of more than 1000 samp 1 es were co 11 ected and tested. A summary of 1 aboratory test- ing is shown on Table 3.4. Testing included determination of: -grain size; -moisture content; --Atterberg limits; and -Proctor densities .. Results of these tests are discussed in Sections 6 and 8. {b) Continuing Tests In addition to the field testing tests and concrete aggregate tests A and K, and Borrow Sites E and G. presented in Sections 8 and 9. 3 .. 6 -Borehole Instrumentation (a) Groundwater Levels program, long-term freeze-thaw were completed for Quarry Sites The results of those tests are Throughout 1982, piezometric readings from all previously instal- led instruments were takeh on a· monthly schedule ~tlith the except- ion of several of the summer months for which additional data was not urgently needed. In addition, attempts. were made to return al 'I unreadable piezo- meters to operating status by repairing damaged pneumatic tubing and emplacing protective covers over instrument heads. · All 1982 borings were instrumented with pneumatic and/or standpipe piezometers. The summary of new instrcmentation installed in 1982 is presented in Table 3 .. 2, while the primary characteristics of instrumentation installed in previous years has been summarized for reference information in the project survey and i nstrumenta- tion files. Typical installation diagrams for the 1982(:.\borings are provided on Figure 3.4. 3-6 I I I. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I The first readings of the new instruments after installation were made in October, 1982, with a second reading in mid-December, 1982.. The data obtai ned in the October readings is inc 1 uded in Section 6; however, this data may not be representative since the piezometric levels may not have stabilized. (b) Ground Temperatures Thermistor readings were continued at monthly intervals. Several COE and 1980 borings were returned to service by repairing cables and placing protective casings over holes with permanent thermisN tor strings.. In addition, antifreeze was added to several stand- pipe-type thermistor probe casings to avoid further difficulties with freezing of the water in the probe pipe. Several COE bor- ings, which were filled with water or diesel fuel, remain non- functional during part or all of the year due to freezing and will require f1 us hi ng and fi 11 i ng with ant·ifreeze before they become fully operational. During 1982, most of the 16 borings drilled in the Watana Relict Channel and Borrow S1te D area had standpipe thermistor rrobe cas- ing (PVC pipe) installed to the bottom of the hole. The closed- bottom pipe was filled with ethylene glycol antifreeze solution to be read with the portable thermistor cable. Cas1ng was sized to allow downhole geophysical logging at a later date. One boring (AH-020) was also instrumented with a multi-point thermistor string similar to those installed in diamond drilled borings at the Watana damsite. The results of the instrumentation program are presented in Sections 5, 6, 8, and 9. 3-7 I I I I I I I I I I I I I I I I I I I INVESTIGATOR AND YEAR COE, 1978 AAI, 1980-81 AAI > 1982 TABLE 3.1: WATANA RELICT CHANNEL/BORROW SITE 0 SUMMARY OF INVESTIGATIONS TEST PITS Number Series 14 TP-8 thru TP-21 2 W-80 29 W-82 AUGER , ,:I_ES Number Series 24 AP-1 thru AP-24 14 AH-D-1 thru AH-D-14 ROTARY/CORE BORINGS Number ·series 11 DR-13 thru DR-20, DR-22, DR-26, DR-27 0 16 AH-015 thru AH-030 TABLE 3.2: WATANA RELICT CHANNEL/BORROW SITE 0 SUM~ARY OF 1982 DRILLING PROGRAM HOLE SURFACE NUMBER LOCATION ELEVATION AH-015 Borrow Site D 2313.9 AH-016 Borrow Site 0 2271.3 AH-017 Borrow Site D 2383.1 AH-018 Borr.ow Site D 2341.4 AH-019 Borrow SiteD 2261.8 AH-020 Watana Relict Channel 2162.1 AH-021 Borrow Site D 2272.7 AH-022 ' Watana Relict Channel 2092.8 AH-023 Watana Relict Channel 2163.0 AH-024 Watana Relict Channel 2165.9 AH-025 Watana Relict Channel 1986.7 AH-026 · Watana Relict Channel 2214.7 AH-027 Borrow Site D 2148.8 AH-028 Borrow Site 0 2226.3 AH-029 Borrow Site 0 2411.0 AH-030 Watana Relict Channel 2221.4 PN ~ Pneumatic piezometer tip SP ~Standpipe piezometer, porous tip MPT ~ Thermistor string DEPTH OF HOLE 84.0 ft 193.0 ft 230o0 ft 189.3 ft 215 .. 0 ft 151.5 ft 188.7 ft 24.0 ft 160.0 ft 58.9 ft 90.0 ft 109.9 ft 195 .. 0 ft 234.0 ft 158.0 ft 100.0 ft INSTRUMENTATION None PN, T SP, T PN(2),T PN(2 ), T MPT PN(2),T PN, T PN(z),T PN, T PN PN iJPT PN PN PN T ~ Polyvinylchloride (PVC) pipe filled with ethylene glycol for portable thermistor prob~ readings I I I I I I I I -I I I I I I I I I I I ------ LINE NUMBERS LOCATION SL82-1 Watana Damsite SL82-2 Watana Damsite SL82-3 Watana Damsite SL82-4 Watana Damsite SL82-5 Watana Damsite SL82-6 Watana Damsite SL82-7 Wat ana Damsite SL82-8 Watana Damsite SL82-9 Watana Damsite SL82-10 Watan a Dams it e SL82-11 Watana Damsite SL82-12 Watana Damsite SL82-13 Watana Damsite SL82-14 Watana Damsite SLB2-15 Wat ana Damsite SL82-16 Watana Relict Channel SL82-17 Watana Relict Channel SL82-18 Watana Relict Channel SL82-19 Watana Relict Channel SL82-20 Watana Relict Channel SL82-21 Borrow Site D SL82-22 Borrow Site D SL82-FL1 fog Lakes Relict Channel SL82-FL2 Fog Lakes Relict Channel SL82-FL3 Fog Lakes Relict Channel *NOTE: ---------- TAStE 3.3: WATANA DAMSITE VICINITY LENGTH OF LINE (linear feet) 1,300 550 550 1,950 3,375 1 ,650 350 1 '100 1 '100 1,100 1,650 2,200 1,550 3,150 1 '100 1,100 5,500 6,600 1,700 6,400 1' 100 3,200 23,100 15,400 6,600 SUMMARY OF 1982 SEISMIC REFRACTION SURVEYS NUMBER OF SPREADS/SHOTS 3/8 1/3 1/3 4/11 7/20 "3/9 1/3 2/6 2/6 2/6 319 4/12 3/9 6/18 2/6 1/5 6/22. 6/29 2/7 6/27 1/5 3/14 ?lf91u 14/63 6/28 PURPOSE -TO DETEMINE:* Determine bedrock quality, detect shears in downstream portal area Detect NW, N shears Determine bedrock quality, detect shears in downstream portal a~ea Determinr~ bedrock quality, detect shears in dov~stream portal area General t.edrock quality, NW and N trending shears in spillway area Determine bedrock quality, detect shears in downstream portai area Determine bedrock quality in portal and spillway area Bedrock conditions in the llFingerbuster11 , spillway flip-bucket area General bedrock quality ~d and N trending shears Determine power intake area bedrock conditions, detect E-W shears Determine limit of 11 The Fins", NW and N trending shears Detect NW, N trending shears Dete-ct NW, N shears, western limit of "The Fins 11 Detect 11 The Fins", NW and N trending shears Determine if 11 The Fins11 continue to the southeast Provide fill-in data to prJduce consistent estimate of top of bedrock elevations Determine width, location of relict channel!=' determine approximate bedrock gradierl'-· of thalwegs ~lines had a common purpose of detecting overburden thickness to provide data for preparation of top of bedrock meps; and to establish data continuity across gaps in previous data. - - TABLE 3.4: WATANA RELICT CHANNEL/BORROW SITE D SUMMARY OF LABORATORY TESTING INVESTIGATOR AND YEAR COE, 1978 AAI, 1980-81 · AAI, 1982 TOTAL, ALL INVESTIGATORS TP = Test Pit SERIES TP AP DR W80 AH-D W82 AH-D AP = Auger Probe SAMPLES ATTEMPTED 18 44 97 2 146 31 697 1,035 DR~ Drill Hole, rotary AH = Auger/Rotary overburden dri 11 ttol e WBO = Watana exposure sample (1980) W82 = Watana exposure sample (1982) SAMPLES RECOVERED 18 44 87 2 111 31 540 833 GRAD,L\TION ANALYSES 18 44 59 2 37 31 357 548 MOISTURE CONTENTS 0 12 15 2 39 0 362 430 ATTERBERG LIMITS 0 34 12 2 21 1 41 111 ------------- I I I I I I I I I I I I I I I I I I I STRATIGRAPHIC UNIT c D D' ~1 E/F G G' H I J/J I K TABLE 3. 5: \~AT ANA RELICT CHANNEL/BORROW SITE 0 SU~XARY OF LABORATORY TESTING BLOW HOI STURE ATTERBERG COUNTS CONTENT GRADATIONS LIMITS 91 64 78 4 24 23 33 5 14 11 12 2 48 38 32 5 199 112 137 16 70 124 87 39 40 19 31 1 9 6 7 0 52 24 32 1 10 10 10 2 c 0 0 0 557 431 459 75 *plus 1-1978 COE Composite Sample from units C through F PROCTOR STANDARD AND MODIFIED 1* * * 0 8* 2 0 0 0 0 0 11 NOTE: This summary does not include testing from any AP Series (COE 1978) holes, DR Series (COE 1978), and AH-D Series (Acres 1980) because some borings could not be correlated by stratigraphic unit. I I I I I I I I I I I I I I I I J •• I I NOTE All reference on the Figures to Appendix D should be changed to Appendix C. I I I I I I I I I I I I I I I I I I I ~ ... TPR-8 & ""' }!; H.l • ~-:! J\11·~-22 p § (.) <q' !'- t...~ ' '\ -~ ·.~./~."· /~ . /~' . ·;,/'· .;-· ,_ <D ' co ..J <Jl. .. fiiiJ TPfHI .1 .. r .[ ~ ·--· ...... ."'-'··''. WATANA DAMSITE EXPLORATION MAP [~';'/( ~~ {\j . 0 Cl) _, II) . o:J: ~t· \l'' -1! ~~~ - LEGEND BOREHOLES AND TEST PITS: 0 DR-19 1978, COE ROTAHY DRILL BORING q_nH-l I978,COE t DIAMOND CORE BORING, HORIZONTAL ( PROJECTIONS AS SHOWN BH-8 1980-BI.AAl j •TPR·ll 1981, AAI BACKHOE TEST PIT '.AH-C-22 1982,AAI ROTAR't/OIAMOND CORE BOf<iNG P INSTRUMENTATION (P= PNEUMATIC l?~EZOMETER) GEOPHYSICAL SURVEYS: & , .;:.. SEISMIC REFRACTION SURVEY END OR 'TURNING POINT DM-C 1975, DAMES a MOORE . SW-1 1978, SHANNON a WILSON SLBO-l 1980-Bt, WOOOWARG-t.LYl}~ CONSlll.TA.>rrs SL82-l 1982, WOO!lWARD-ClYOE CONSULTANt~ !:!~ L BASE MAP FROM 1978, COE-.1"= 200' DAMSlT':; 'r01-UGRAPH'1' SHEETS 8,13 OFZ6. ?. CONTOUR INTERVAL 50',. TRACED FROM R::~~!NCEO BASE MAP. 3. EXTENSIONS OF EXPLORATIONS Tl'l NORTH SlivWN ON FIGURE 3.2. 4. S a W SEISMIC LINE lOCATIONS CORRECTI;~ fROM ORI\;:NAl. FIElD BOOKS AND Sa W1 1978. 5. EXPlORATION LOGS AND SEISMiC LINE SfC""f)J;J.'fS SHOW~ IN APPENDICES A AND D, AND AAI, 1982. SW-2 ·' =....!:.-, .... ,,---~---'--'---~-------,.~ .. ,~~:§ .•. f • 0 Cl) ..J II) SCAlE O~~~~~~~~:!O!JO~ ....... -• .1.,~00 FEET C .. "" - FIGURE 3.1 I I I I I I I I I I I I I I I I I I I ··, ... '"<~ ? ~ . . ·. · .. '• '0 AP-17 TP-9 1111® AP-21 ® AH-0-!2 ®AP-20 ¢AP-19 • !1: U) AH-0-3 AH·!l-18 2P , .. ,. -....... ? ~ .. ~~, AP-23 TP-11 ~ . Ai'-24 .. TP-10 <XlAH-D-11 111 TP-13 • TP-12 WATANA RELICT CHANNEL/ BORROW SITE D EXPLORATION MAP SHEET I OF 2 ~ AH-0-8 ®AH-D-6 "''· . CXl ·: ' AH-0-14 NOTES; L LEGEND ON. SHEET 2. 2. BASE MAP fRO~~ 1978.C()E-I"=~:O' OAM..~E l'OPOORA..<=!oo"'i' SHEETS 8,9,13-15,18-20 OF 26. 3. SEISMIC LINE OM -B CONTINUES U,OOQ FEET NORTH ~ TURNING POINT SHOWN. SCALE Q E 40(' BOO FEET =- I ·I I I <30R-20 I I I L . . ~ -"--""#""' · --~~-~-~i-s·. I I I I ·;: H,.,, ' I ,. I I I I I I DR-16 0 .. ~.:·wf.!~"'·i?t ;_,._ '' ~-- ~¥. BS ·co -,.."~WS.:rl'>4 <£~~~~= ... 64~ WATANA RELICT CHANNEL/BORROV/ SITE D EXPLORATION MAP SHEET 2 OF 2 t; -Ntl2...A..Z ~.. . ,-,. LEGEND CONTACTS: -·-SORROW SITE LIMIT GEOPHYSICAL SURVEYS: DM·A SW•l SL.80-8 SEISMIC REFRACTION SURVEY EN!l C.R TURNI~ .1 .POlft.,.. 1975, DAMES e. MOORE 1978, SHANNON 6 WILSON 1980-81, WOODWARD-CLYDE CONSt!L~~TS 1982, WOODWARD-CLYDE CONSULTA~"!$ BOREHOLES AND TEST PITS: ~·J DR-27 1978, COE ROTARY DRILL BO~ING <&; AP•21 1918, COE AUGER BORING (6)AH·D·I2 1980, AAl AUGER BORING f•H "• 191>2, AAI AUGER/ROTARY/DIAMO!m ~.JR"E 60R1NG • TP·tl 1918, COE BACKHOIO. TEST PIT ','\.WB0-202 1960, Alit BULK SAMPLE LOCATIO!>t ''1'16~ ~I'• ma~, AAi BULK SAMPLE LOCATIQllii NOTES: I. BASE MAP !'ROM i978,COE-1"=200'1,)AM$i~ 'TOPOGRAPHY SHEETS 7,8,12.,13,17,18 OF 26. 2. CONTOUR INTERVAL 25 FEET, REDUCED ~"i.tl ':'RACED FROM· REFERENCED BASE MAPS. '3". fXTENS!ONS OF fY_I>l OR.ftTJONS TO SC.tmi A.~ t!AMStTE f-XPLORATION PLAN SHOWN ON FIGURE 3.1 4. EXPLORATION LOGS AND SEISMIC LINE SEC""~~ SHOWN !N APPENI.JICES A AND 0, AND AAI, 1982. 0 40~., 800 FEET SCA~E et---~~---~iamH&·-·za• FIGURE 3.2. I I I I I I I I I I I I I I I I I I I ~--~--===------~--~--~----------~--~ \ , II '• ' \ \~ '\(t!'. ·\;~ \<.,. \ r-FOG LAl<ES REFRACnON LINE \,'- ./ SEGMENTS SLSI-FLl TO SL81-FL48 , 12. WATANA ~'. :''7- 28 \ 29 \ "" . ' ' \, \, FOG LAKES RELICT CHANNEL EXPLORATION MAP \. '\\, ~ !~ ~-. "' ~-.. '• .-·,·! '· .• ,j LEGEND: GEOPHYSICAL SURVEYS: /1;.,8 SEISMIC REFRACTION SURVEY END OR TURNim PO!MT. SLai·FLI 1981 1 WOODWARD-CLYDE CONSULTANTS. Sl.B2•F\..2 1982, WOODWARD-CLYDE CONSULTANTS. NOTES: I BASE MAP MODIFIED Ff!OM U.S.G.S. TAU<~"iiNA MOUTAINS ;:-.s . AND 0·4 QUADRANGLE MAPS, SCALE llN."' ·fMI. 2. SEISMIC LINE SECTIONS SHOWN IN APPEN~X 0 AND AAL •. ~. SCALE 0 E ... 2000 4000 FEET .. ~ ..... FIGURE 3.3 I I I I I I I I ~I I I I I I I I I I I I r ~ TYPI.CAL STANDPIPE PIEZOMETER INSTALLATION PROTECTIVE STEEL STANDPIPE TYPICAL THERMISTOR STRING INSTALLATION GROUT-~~ PROTECTIVE. STEEL STANDPIPE HOLE BACKFILLED WITH -CUTTINGS OR OTHER AVAILABLE MATERIAL 1+---I'' PVC PIPE ·1-<f---SLOUGH FROM HOLE WALLS TYPICAL PNEUMATIC PIEZOMETER INSTALLATION (WITHOUT PVC PIPE) TUBl~(; LEAD ----fOR READOUT ------~~1~~-----~ ~ J-c·--GROUT ~~ ~J !~ '!· HOLE DIAMETER . _ _,,.....··~.:. ~· CHANGE ~ .. PNEUMATIC . .. >· .~ . . ~~ . : . .. : .. ~ ' --· -· _PEA GRAVEL AND SAND .. ~ •• ·:to. ,__ __ BENT~NITE SEAL ~ t'-t TYPICAL PIEZOMETER ----IIliA 1 TIP ._ __ PROCESSEII FILTER SAND 5' TYPICAL TYPICAL PNEUMATIC PIEZOMETER INSTALLATiON (WITH PVC PIPE) ·~ 2 Vt' PVC PIPE Ftu..E:O lr ~~WITH ETHYLENE Gt.YCOL -----...o.tl:t-1 ,._ __ HOLE DIAMETER CHANGE PEA GRAVEL-··---.jilt PNEUMATIC PIEZO':!ETER . ---• TIP "S \SHALLOW) PROC~SED fll.TER SAND 5 TYPICAl.. BENTONI~E SEAt. 1»'---I' T't'f' ~ AL H----PROCESSED FiLTm SAND 5'TYPJCAL ~----BENTONITE SEAL liot.E DIAMETER CHANGE lli-OIIc-----BENTONITE: SEAL PNEUMATIC D""---PIEZOMETER TIP "D" !DEEP) !(S(S~~---BENTONITE SEAL ,rt . ~~~,!~ .. '~.,...--SLOUGH FROM HOLE --l!. WALL TYPICAL. INSTRUMENTATION INSTALLATION DETAILS NOTES: I) ALL DRAvm:Gs GRAPHICALLY REPREsENTI:D AND NOT TO SCALE 2) HOLE DIAMETER CHANGES ARE DUE TO DRILLING TOOL SIZE CHANGE. FIGURE 3.4 I I I I I I I I I I I I I I I I I I I 4 -WATANA AREA GEOLOGY 4ol -Introduction .' Thi,? section discusses the bedrock and surficial geology of the Watana area which includes· the Watana damsite, Watana and Fog Lakes Relict Channels, and ail the major quarry and borrow sites.. A surficial geo- logic map of this area is presented in Figure 4.1. Detailed discussion of the regional geology is presented in the 1980-81 Geotechnical Report (1). The following discussions have been limited to the regional geo- 1 ogy within the immediate Watana area. 4.2 -~erburden and Topography The Watana area lies w-ithin the Upper Susitna River Basin in the Talkeetna Mountains of south-central Alaska. The river basin is a high, broad plain of low relief formed by repeated glaciations. Tn~ Sus i tna River has incised a deep (over 800 feet) , east-west tr~:~di ng gorge into this plaino Numerous lakes ·::lnd low rounded hillocks cover' much of the area. Unconsolidated Quaternary sediments mantle tr~e area . (40} and are discussed in Section 4.5. D 4.3 -Bedrock Stratigraphy The oldest rocks which outcrop in the Watana area are a metamorphosed upper Paleozoic (Table 4.1) rock sequence which trends northeastward along the eastern portion of the Susitna River Basin in the Talkeetna Mountains (Figure 4.1). These rocks consist chiefiy of coarse to fine grained clastic volcanic flows and tuffs of basaltic to andesitic com- position, which locally contain marble interbeds. This sequence of rocks is unconformably overlain by Triassic and Jurassic metavolcanic and sedimentary rocks.. These rocks, which consist of a shallow marine sequence of metamorphosed basalt flows interbedded chert, argillite, marble, an~ volcaniclastic rocks, are exposed in the eastern part of the Watana area along Watana Creek and in the Fog Lakes Relict Channel (see Section 7). Paleozoic and lower Mesozoic rocks are intruded by Jurassic p 1 utoni c rocks composed chiefly of granodiorite and quartz diorite. The Jurassic age intrusive rocks form the batholithic com~~ex of the Talkeetna Mountains, both north and south oc the Watana area (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 ofllf" argillite and graywacke d'';ring the Cretaceous. Following deposition, the region was uplifted, intruded and met1morphosed. These rocks underlie a large portion of the project area including the Devil Canyon damsite (10). In the vlatana .,)t>ea, argillite and graywacke outcrop alan the Susitna '~r ~ '~ma•,"ily between Deadman Creek and the Talkeet":a Thrust Fault, ar.u also in the Fog Creek area. 4-1 The-Cretaceous rocks were intruded in the Watana area by a series of Tertiary age plutonic rocks ranging in composition from granodiorite to diorite • ..,.. The Watana damsite is underlain by one of these plutons. Diorite similar to that in the damsite is found in Deadman and Fog Creeks and north of Borrow Site D. Granodiorite is found near the site on Tsusena Creek (7). Whether these two rock types represent two plu- tons or differentiation within one pluton ·;s not known. Subsequent, but probably related to the emplacement of the plutons, was the extrusion of a sequence of volcanic rock and deposition of volcan- iclastic rocks. These rocks consist primarily of andesitic to basaltic flows, but primarily andesite porphyry. The contact between the ande·- site porphyry and diorite pluton is exposed in the damsite area (Section 5.1) .. Downstream of the damsite, a thick volcaniclastic sequence occurs in the andesite porphyry units. The volcaniclastic rock consists of several hundred feet of interbedded volcanic sandstone, siltstone and shale, and possible felsite, dipping gently tn west. The upper ande- site porphyry appears to unconformably overlie the tilted volcaniclas- tic rock, indicating two episodes of this volcanic _.:tivityoi · The youngest Tertiary rocks in the damsite area·are partially lithified sedimentary rocks consisting of conglomerate, sandstone, claystone and minor coal (11).. These deposits are only exposed along Watana Creek north of the Fog Lakes Relict Channel. 4.4 -Tectonic History At least three major episodes of deformation are recognized (10) for the Watana area: -A period of jntense metamorphism, plutonism, and uplift in th~~ Jurassic; -A simi 1 ar orogeny during the mi dd1 e to late Cretaceous; and -A period of extensive uplift and denudation in the middle Tertiary to Quaternary. The firs.r: pet"'iod (early to midd1e Jurassic) was the first major oroge ... nic ever· in the Susitna River Basin as it now e~ists.. It was charac- terized ;J the intrusion of plutons and accompanied by crustal uplift· and regi ·. ,:·'1 metamorphism. Most of the structural features ir the region are the result of the Cretaceous orogeny associated w~th the accretion of northwest drifting continental blocks into the North A~erican plate. This plate conver- gence resulted in complex thrust faulting and folding which produced the pronounced northeast/southwest structurdl grain across the region. The argi11ite and graywacke beds were isoclinally folded along north- west trending fo 1 ds during this orogeny. The majority of the struc- tural featuress of which the Talkeetna Thrust Fault is the most promi- nent in th-e Ta lkeetn& Mountains H) are a consequence of this m~ogeny. The Talkeetna Thrust is postulated as representing an old suture zone, 4-2 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I involving the thrusting of Pale:0zoic, "Triassic and Jurassic rocks over the Cretaceous seaimentary rocks (10, 11, 14, 15, 24). Other compres- sion a 1 structures re 1 a ted to this orogeny are evident in the intense shear zones roughly parallel to and southeast of the Talkeetna Thrust. Tertiary deformations are evidenced by a complex system of normal, obl·ique slip, and high-ang1e reverse faults. Two prominent tectonic featur?s of this period bracket the basin area. The Denali fault, a right-lateral, strike-slip fault 25 miles north of the Susitna River, exhibits evidence of fault displacement during Cenozoic time (9). The Castie Mountain-Caribou fault system, which borders the Talkeetna ~1ountains approximately 70 miles southeast of the sites, is a normal fault which has had displacement during the Holocene (13). At the damsi te, "The Fins" and "Fi ngerbuster 11 shear zone crosscuts Tertiary age volcanic rocks and may be related to this episode .of de- formation. 4.5 -G1acial History A period of cyclic climatic cooling during the Quaternary resu.ited in repeated glaciation of southern Alaska. Little information is avail- able regarding the glacial history in the upper Susitna Riv-er Basin. Unlike the north side of the Alaska Range, which i~ characterized by alpine type glaciation, the Susitna basin experienced coalescing pied- mont glaciers from both the Alaska Range .and the Tn lkeetna Mountains that merged and filled the upper ba~1n ar~a. At le~~t three periods of glaciation have been delineated for the area based on the glacial stratigraphy (18:~ ?('). During the most recent period (1 ate Wi sconsi ni an)) glaciers t' t 1 ed the adjoining 1 ovJl and basins an~ spread onto the continental shelf (18). Waning 0f the 1ce masses from the Alaska Range and Talkeetna Mountains formed ice bar- riet~s v.Jhich b1ocked the drainage of glacial meltwater ·and oroduced pro- gl.acial lakes. As a consequence of repeated gl aci ati ons, the Susitna River basin is covered by varying thicknesses of till, outwash, lacustrine and ice disintegration deposits. The till is primarily a basal till which in the Fog Lakes area, is characterized by a fluted ground moraine sur- face. In th~ upper portion of Watana Creek, significant thicknesses of lacustrine deposits are exposed at the surface (not seen nn this map} which resulted from preglacial lakeso On the north side b1 the Susltna River, from Tsusena GrGek to just upstrecm of Deadman Creek, ice dis in- tegration deposits are visible. These formed as a consequence of rapid deglaciation as the glaciers began thinning and were cut off from their source, leaving large debris covered glacier bodies which stagnattd in place. This was the last glacial event in the Watana area as the gla- ciers which fed this area r2treated to the north. 4-3 I I I I .. I I I I I I I I I I I I I i ERA Cenozoic Mesozoic I - Paleozoic Precambrian Reference (38) TABLE 4.1: GEOLOGIC TIME SCALE PERIOD EPOCH Quaternary Holocene. Pleistocene Pliocene Miocene Tertiary ~Oligocene Eocene Paleocene Cr eta:!:eous Jurass~ic Triassic Permian . Penr:sy1 van1 an Mississippi&.n Devonian S ., • 1 .. ur 1 an Ordovician Cambrian ' . GLACIATION I Wisc.onsir.ian Illinoian Kansan Nebraskan t~ILLION OF '/EARS AGO ,. 1.8 70 l 230 600 I I I I I I I I I I I I I I I I I I I r---------~--~----------~---------------------------------------c------------------------~----------------~----~----------------------------------------------------------~ . ~·. J::''. Ql , .. ·· .. ·~··· ,. .. ·· \ Ot \ / ,_ Qt ·' '_, Qt ~-· ..... ··'' ~ ...... _.. ......... ..... ·· ~-··· ..... · ' ( > . I ,:·~~ ! I \ ) ~"!. ·C"! ~\: \. '\ ( • \ \ ""\ WATANA DAMSITE AREA GEOLOGiC MAP SHEET I OF 2 \ \ Q::! ..... ~-··· ~···· .. Qo .... · ~)'. :'>"""1\::,~·.-:' li LEGEND: LITHOlOGY: CENOZOIC QUATERNARY ~ GJ SIJRFICIAL OFPOSITS,UNOIFFERENnATED, GEN~" THIN ALLUVIUM, ALLUVIAL TEiRRACES A.'*!> FANS ~;;;] ICE DISINTEGRATION DEPOSITS [§_: 1 OUTWASH. G:!_] TILL. TERTIARY ~ CONGLOMERAtE, SAND!> TONE ANDCL>\YSTONE. CJ VOLCANICLASTIC SANDSTONE, SILTS!l:lNE AND St'...:u£ Ed ANDESITE PORPHYRY, MINOR BASA1.:r lllliiiiiliD DIORITE TO QUARTZ DIORITE, MiN~ "RANOOl.:'iii-=; ~~'~;:~l~ BIOT:TE GRANODIORITE MESOZOIC CRETACEOUS r==:J ARGILLITE A~!D GRAYWACKE. TRIASSIC r~ SASALTIC METAVOLCANIC ROO<$, Mi;;'h\SASA1..T .~!'<'C ~ U....u... PALE:OZClt t·.· .. ·.·.··;-"1 ' • j • + " BASALTIC TO ANDES!nC METAVOL\:A'.\.: ROCKS CONTACTS· BEDROCK, DASHED WHERE lNFERN:-:- 8E[)q()CI( I SURFICIAL DEPOSITS, ~"HtO \\'1lE:.lf.:: APPROXIMATE. SURFICIAL DEPOSITS, APPROXIMA'Y'~ STRUCTURE: .A .... A THRUST FAULT, TEETH ON UPruR\"'\\N SlOE NOTES: SHEAk, NEAR VERTICAL TO VElU!C~, UNLESS OrP S-{.)'1\"N, EXTENT WHERE KNOWN AND/OR f!I.~RREO. JOINTS, INCLINED, VERTICAL BEDDING .. INCUNED, VERTICAL. SYNCLINAL AXIS. 1 GEOLOGY MODIFIED FROM CSEJTEY AND CTH~~ :978 2 DETAIL MAPS OF THE W,I,TA.NA OAMSITE ON F: <;l.<i<ES 5.2,5 ;z. .:t.•~·· 516 3 BASE MAP MODIFIED FROM USiiS TA' x:_'-"'X,::. M.:lUNTAlNS ;:.,~ AND D•4 QU-i:iRANGLE I'JAPS, ~CALE nr-;:H ~ !MILE 4 EXTENT OF L.ITHOLOGY AND STqUCTUrtEARE S:0'5ED 00 A.lRF-:-"~ INTERPRETATION AND LIMITED FIELD INVES't.i;ATWN A:· "l An~ SUBJECT TO VERIFICATION THROUGH Fl!TUR~ .::'E'TAJLCC INVESTIGP.TIQNS. Q 2000 4000 FEET SCALE ---, _ .!'h.["'.--, FIGURE 4.1 J l l I I I I I I I • I I I I I I I I I I 1 { ~ Qo WATANA OAMSI1-E AHEA GEOLOGIC MAP SHc.ET ~ Or 2 Qt .1' .· ..... ,j' ' / ' ' ( ' ( / ' _j NOTE: 1. EXPLANATION FOR SYMBOLS ON SHEET l I '! I / I o z!Jtif./ 4c.,:-~-;'E4 ~ !" SCALE C22_::5 ... , ... ~- --------------------~_,_ ___________ _ FIGURE 4.1 .----------., • l. I 1 l I I I I I I I I I I I I I I I I I I I 5 -RESULTS OF GEOTECHNICAL INVESTIGATIONS -WATANA DAMSITE 5.1 -Main Dam Foundation (a) Overburden (i) Introduction A map showing the too of bedrock surface and the type and distribution of surficial sediments in the Watana damsite is presented on Figure 5.1. Geologic profiles depicting subsurface stratigraphy in the main damsite and borrow sites are presented in later sections. Determination of the overburden thickness and material types is based on geologic mapping, seismic refraction surveys, boreholes and test pits. Exploration locations are shown on Figure 3.1. Table 5.1 provides the correlation of seismic velocities with soil and rock types used for this study. Data used in developing these figures and tables is presented in Appen- dix C and the 1980-81 Geotechnical Report (1). (ii) Damsite Detailed geologic mapping and the additional 21,373 linear feet of seismic refraction· survey performed during 1982 have resulted in a refinement of the top of bedrock and surficial geologic map presented previously (1). A detail- ed discussion of overburden conditions for the upstream cofferdam -and portal area, downstream cofferdam and portal area, and intake and spillway areas is presented in Sec- tions 5.2, 5.3 and 5.4 respectively. Refer to the 1980-81 Geotechnical Report for a discussion of overburden condi- tions in the main damsite area (1). (b) Bedrock Lithology (i) Introduction The Watana site is located on the western side of a Ter- tiary age (Table 4.1) igneous plutonic body Vlhich consists primarily of diorite and quartz diorite (Section 4). This pluton is bounded in the west area by argillite, andesitlc volcanic flows and volcaniclastic sedimentary rocks. These rocks have not been assigned formational nam~s, but rather have been described by standard 1itho1ogic types (26) for mapping and correlation purposes. The lithology and structure at the Watana damsite jre shown on a geologic map, Figure 5.2, and five geologic sections, W-1 through W-5 (Figures 5. 3 to 5 .. 7).. In addition> detailed geologic maps of ~he upstream and downstream fi-1 cofferdam and portal areas are shown on Figures 5.12 and 5.16, as well as by geologic sections (Figures 5 .. 13 and 5.17). The geology shown in these figures is based on field map- ping, borehoh.:s, and seismic refraction data (Section 3). Where pass i b l e, mapped surface structure was corre 1 a ted with subsurface drilling and seismic refraction data. How- evar, the limited rock exposure ~nd the widely spaced sub- surface exploration data in the <.::rr_;ite frequently required extrapolation of geologic contaL ·s and structural features over considerable distance. fhere are a number of uncer- tainties which exist in the interpretation of the nature of the materials in the 6,000 to 10,000 feet per second (fps) seismic velocity range. This material was interpreted to be bedrock, although velocities in this rar,ge are more typical of well consolidated soil.s. Bedrock outcrops, which uccur in some of these lower velocity zones, consist of competent rock that would be expected to have higher seismic velocities. Therefore, future investigations will be necessary to confirm the location and continu1ty of the features shown in the fi gur.es, and of the top of rock map p- i ng. For simplicity, borehole information shown on Figures 5.3 through 5.7 is limited to features five feet or greater in thic'·ness. More detailed information is contained in Appendix C, and Appendices B, D, H, ard I of the 1980-81 Geotechnical R~port (1). 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 les~ frequent (Figure 5.1).. The rocks of th-e 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 increasiflg in silica content from diorite to granodiorite. The rock types are observed in both outcrop and boreholes to grade smoothly from one to th0 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 center 1 i ne. Simi 1 ar contacts are found in boreholes BH-6 and P.r-t-8 (Appendix B, Reference 1) over 0.3 feet at Elevation 1 .~94 and 3.8 feet at Elevation 1708, respectively. Si nee no mappab i e patterts was found to differentiate these chree r~ock types, they have been com- bined on the geo1ogi'c map and :,e-:tions under the general name of diorite. 5-2 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I The diorite is described as a crystulline ~gneous 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 foliation.. Grain size varies from fine (less than lmm) to medium (1-5mm) but is usually medi- um. 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 i 5 usually 10 to 15 percent. The fe 1 dspar 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 biutite and hornblende, are generally fine grained. The hornblende is often partially chloritized. Trace amounts of sulphides and c3rbonate also occur within the diorite. Inclusions of argi 1 lite have been observed in the diorite in 11 The Fins 11 and tne 11 Fi ngerbuster 11 areas (Figure 5. 2) u The diorite is generally fresh and hard to very hard. The rock is slightly weathered along the joint surfaces to depths of about 50 to 80 feet. 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 ha~ caused the chemical breakdown of tht;. feldspars and mafic minerals. The feldspars have altered to kaolinite clay and the ~afics have altered to chlorite. Hydrothermal alteration is discuss.ed in detail in Section 5.l{c). · ( i i ·i) Andesite~.orphyr,t The name andesite porphyry is used for a varied group of apparently related extrusive rock types (28).. The a~ldesite porphyry occttrs a 1 ong the western side of the di or ,e pl u- ton and is exposed in outcrops on both sides of the Susitna River (Figure 5.2). On the south bank, outcrops occur across from the "Fi ngerbuster 11 and at apprt'Ximate Elevation 1750 immediately downstream from the dam centerline. And~ sit2 porphyry was drilled in boreholes BH-4 {Figur·e 5.3), BH-8 (Figure 5.4), and BH-2 (Figure 5.6) to depths of 96.0, 43.0 and 1G3.0 feet, respectively. Borehole OH-28 bottomed at 125 feet in the porphyry (Figure 5.7). Andesite ror- phyry dikes are also found interspersed in the diorite. On 5-3 c ( i v) the north bank, the andesite is exposed at river level in the 11 Fi ngerbuster 11 area and in scattered outcrops to about Elevation 2350 .. The andesite porphyry is a 1 i ght to medi urn 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 oid of a microscope) with generall:' 10 to 30 percent of fine to medi urn grained pl agi ocl ase f~ldspar phenocrysts. Lithic inclusions are found through- out the andesite porphyry but are most concentrated near the contact with the diorite. Concentrations of subrounded to subangul ar fragm~nts. up to 6 inches in diameter, of quartz diorite, argillite and volcanic r0cks vler"e found above the diorite contact in BH-8 (Appendix B, Reference I). The andesite porphyry is fresh to slightly \'leathered and hard. Hydrothermal alteration is not common in the andesite porphyry. The andesite porphyry also contains layers or zones of dacite and latite. The latite occurs in the "Fingerbuster .. area and the dacite in Quarry Site A (28). ·These varied rock types appear to be irregular and discon- ti~uous in the site area and could not be mapped over large areas. Therefore, the term andesite porphyry has been used as a general term fo~ 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 borehole_ in the areas of abundant 1 it hi c frag!llents. On thL south bank, about 350 feet northeast of DH-28, the flow structure strikes east-west and dips 20° to the south. In the "Fing- erbuster11 area, flow !: ... "'uctures strike northwest-southeast and dip 15° to the west. A photograph of the andesite ~or phyry with numerous lithic inclusions, as well as, flow structvr~ 1 i neati on, is shown in the 1980-81 Geotechni ca 1 Report\lJ. Contact Between Andesite Porphyry and Diorite The contact between the andesite porphyry and the under- lying diorite has been mapped immediate ;y downstream from the proposed dam centerline, extending in a general north- westerly direction across the south abutment and northerly across the north abutment (Figure 5.2). On the south bank it is intersected in BH-8 and BH-12, "And is exposed in one outcrop west of the dam centerline at about Elevation 1750. At this point, between 400 to 800 feet northeast of DH-28, 5-4 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 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. A photograph of the closely to very closely spaced joints in the andesite porphyry immediately above the di pr)i te contact is shown in the 1980-81 Geotechni ca 1 Report \1 • Where the contact is ·exposed on the south bank, minor shearing, ·1 ess than 1 inch wide, occurs uetween the ande-_ site porphyry and the diorite. The contact in this area strikes nearly east-west with a dip of 45° to the south. In BH-8~ the andesite porphyry/diorite contact is found at a depth of 43.0 feet. From.38.4 to 43.0 feet, thin layers of andesite porphyry are modet~ate ly to severely weathered with 1ayer·s of si0lty 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 wi tn generally c 1 ose ly to moderately c I ose ly spaced 2oi nts. The contact occurs over a 3-i nch-wi de zone where th0 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 RQOs. Permeabilities were on the order of lo-5 em/sec. On the north bank, the contact is not exposed but was in- tersected in BH-2 and BH-4. In BH-4, very c~osely spaced joints with silt and clay coating occur in the andesite porphyry from 94ol feet to the contact at 96o0 feet. As in BH-12, very thin fingers of andesite porphyry penetrate the diorite at the contact. The diorite be 1 ow ~he contact is s 1 i ght1y weathered with iron oxide stair ~ n~ in the upper 0. 5 f oct. RQDs are quite ~w, ranging from 0 to 51 percent in the upper 15 feet of the ~iorite. 1)ermeabilities, how- ever, are 1 ow at about 10-em/sec. The contact from river 1 eve 1 ( Elevation 1450) to about El evat; on 2000 in this area is coincident with a major north-south trending shear zone (Section 5.1[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 and not necessarily representative of the contact. Above Elevation 2000, where the contact is not coincident with the major shear zone, the contact is assum·~d to dip gently to moder- ate 1y northwest .. ( v) Dikes The diorite pluton has been intruded by both m3fic and fel- sic dikes. No dikes were found in the andesite por·phyry. Because of their small size, the dikes could not be deline- ated as mappable units. 5-5 Felsic dikes are found in o·utcrops and in all boreholes. Felsic dikes are light gray and aphanitic to medium grained, but generally fine grained. The •elsie dik~s are composed primarily of feldspar (plagioclase and orthoclase) with up to 30 percent quartz and less than 10 percent mafics. Contacts with the diorite are tight and "welded 11 • 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 16 inches by shears and healed shears in outr~op (Section 5.2 [c] and in brireholes (BH-3 at 702.7 and 801.3 feet). A photograph of a typical felsic dike which was offset( ~long a shear is shown in the 1980-81 Geotechnical Report lJ. Mafic dikes are less common at the site than the felsic dikes. They are rarely seen in outcrop but were found locally 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 aph"'\'litic to very fine, with fine to medium grained plagioclase phenocrysts. The ma-. :c dikes are hard and fresh with tight contacts. Dik.e widths are generally less than 1 foot, although in BH-2, an andesite dike was drilled from 245.8 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 approxi- mately 5 feet wide and consists of fine grained diorite .. 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 dikes, the mafic dikes c0uld 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 intake porta 1. · Outcrops ocCU\' in 11 The Fi nsu on the north bank and in Quarry Site Lon the south bank (Figure 5.2). The dike is porphyritic with an aphanitic to fine grained groundmass. Medium grained phenocrysts, consisting pri- marily of plagioclase feldspar and lesser amounts of horn-. blen>:e, comprise up to 10 percent of the rock in "The Finsu and 20 to 30 ~ercent 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 consi~t of rounded diorite and tabular argillite fragments from 1 ~o 6 inches long. Contacts with the. i ncl usi ons are sharp and tight. The diorite porphyry becomes 1 ess porphyritic and more aphanitic near the contacts with the diorite pluton. The western contact in "The F'i ns 11 is coincident v1ith a 10-foot- wide shear/alteration zone (see Section 5.2 [c]). The eastern contact is not exposed. 5-6 I I I I I I I I I I I I I I I I I I I ~ I I I I I I I I I I ~ I I I I I I •• (c) Bedrock Structure (i) Introduction This section discusses the structur a 1 geo 1 ogy at the vJatana damsite and its relation to proposed site facilities. This section is presented in three subsections: joints; shears, fracture zones, and a 1 teration zones; and significant geo- 1 ogi c features. (ii) Joints Joint data were recorded at all outcrops, as well as a-~ . nine joint stations {WJ-1 through(vJJ-9) which were selected for detailed joint measurements 1). Joint statiuns were chosen at representative areas having good three-d~mension a 1 exposure of major structures and in the major rock types: diorite, andesite porphyry, and dior~te porphyry. At outcrop and ,ioi nt stations, the ori E'ntati ons of major and minor joint sets were recorded, as well as the condi- tion of the joint surfaces, spacing, and any mineralization or coating. Joint measurements were plotted on the 1 ower hemisphere of a Schmidt equal-area stereonet and contoured at 1, 3, 5, 7, 10, and 15 percent. An example illustrating the plotting method (6} is presented on Figure 5.8. Joint $tation Rlots are shown in the 1980-81 Geotechnical Reportl1J~ Composite joint plots WE:re constructed from both joint sta- tion and outcrop 'data. -:-de site was divided into four qua- drants (northeast, southeast, southwest, and northwest). A composite plot for each quadran: is shown on Figure 5.8. Two major and two minor joint ·sets were mapped at the Watana site and dre identified on the composite and joint station plots. Sets I and II ar·e major sets which occur throughout the site area. Sets I I I and IV are minor sets which are generally less prominent but may be locally strong. Each joint set is discussed below. Table 5.2 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 carre- l ate between joints in outcrop and those encountered at depth. Joints in borehole; are discussed in Refe~ence 1. Joint Set I is the most prominent set at Watana~ The aver- age orientation cf the four quadrants is 300° (lable 5~2). Set I consists of two subsets, Ia. and Ib, 'which vary in strike by 20.0 to 30°, but with similar dips. Subset Ia generally trends from 320() to 330° with most dips between 5-7 85°SW and 80°NE. This subset is most strongly developed in the southeast quadrant. Subset lb is usually the more strongly developed ·of the two subsets, particularly in the northwest and southwest 'Wadrants. Subset Ib generally strikes from 295° to 310° \vith an average dip of 75° north- east. Set I joint surfaces are primarily planar and smooth to local1y rough and have an average spacing of 2 feet. Joint surfaces in the diorite porphyr·y in 11 The Fins 11 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 5.8). The joints are continuous and generally tight. Open joints are found at the surface in fracture zones and shears, particularly in •'The Fins .. in the upstream diver- sion portal area and on the south bank (GF 6) on the slopes above the proposed downstream cofferdam. Set I para 11 e 1 s most major shears, fracture zones,· and alteration zones found at the site. In 11The Fins" area, discontinuities primarily parallel Subset Ia; hov1ever, in the 11 Finger- buster11 area these discontinuities parallel Subset Ib joints. The Susitna River is parallel to Subset lb between the dam centerline and downstream diversion portal area. Joint Set II is northeast-trending, ranging in str7ke from 015° to 075° with an average trend of 055° across the site. Most dips are moderate to steep from 60° southeast to 60° northwest with an average dip of 85° northwest. Set II is best developed in the northeast and southeast quadrants where the .trend averages 045° with a preferred dip to the northwest. At joint stations \~J-3 and ~JJ-5, in the up- stream diversion porta 1 area, Set I I is more strongly de- veloped than Set I, while at joint station WJ-6 in the dio- rite porphyry approximately 200 feet upstream from WJ--3, no Set II 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 0uadrants, Set II trends more to the east with an average stril<.e of 065° and near-vertical to vertical dips. Set II joints are generally planar to irregular with smooth to sl ight1y rough surfaces. Joint spacings range from 1 inch in 'fractur~ zones to 5 feet, aver.:~ging 1 to 2 feet. Set II is genera1ly continuous and tight. Open joints were found on the south ba-nk at WJ-1 and at several other out- crops. Fracture zones are associated with Set II joints in the northeast and southeast quadrants at 11 The Fi ns 1 ' and in 5-8 I I I I I I I I I I I I I I I I I I I •• I I I I I I I I I I I I I I I I I I geologic feature GF 3. These zones appear to be di scon- tinuous (see Section !).2 [c]). The Susitna River runs parallel to subparallel to Set II joints in the up~~~eam diversion porta) area. No shears or alteration zones were found associated with Set II joints. Joint Set III is generally north-south trending, ranging in strike between 335° and 035° with variable dips from 45° east to vertical to 60° west. Set III is a minor set al- though 1 oca lly pronounced in the northwest and southwest quadrants. In the northwest quadrant, the average strike and dip are 005° and 80° east. In the southwest, the strike and dip are generally 345° and 80° east (Table 5. 2). Where present, tr1e Set I I I joints range in spacing from less than 1 inch in fracture zones to 5 feet, with an average of 1 to 2 feet. These joints are generally planar to irregular and smooth.,. to rough. Minor carbonate was found at some outcrops in the southwest quadrant. Moderately to steeply east-dipping Set III joints are like- ly to be encountered in tunnels near the proposed dam cen- terline and in the downstream portal area. Fracture and shear zones parallel to Set III were mapped in structura 1 areas GF 6 and in the 11 Fi ngerbuster 11 ( ;:; gure 5. 2). .l\t GF 6 above the downstream cofferdam, Set I I I .~orlils numerous open joints on the cliff face. Joint Set IV consists of numerous low angle {dipping -less than 40°) joints of various orientdtions, the strongest trend being 090° (Table 5.2). In all quadrants, these joints dip both towards and away from the Susitna River .. Set IV joints are planar to irregular, smooth to rough, and discontinuous. Spacing is generaily 1 to 2 feet when pre- sentv No ffiineralization or alteration zones are associated with this set. Shear and fracture zones parallel to this set were found in 11 The Fins 11 area. These appeared to be due to slumping. Set IV joints probably resulted from stress relief after glacial nloading and/or erosion of the river valley, and therefore should not occur at depth. In the 11 Fingerbustt:r 11 area (GF 7), the intersection of open joints of Sets I, III, and IV have resulted in large areas of loose, unstable rock, ~articularly in the proposed loca- tion of the main spillway cuts. At WJ-2 and WJ-4, a strong local joint set striking approx- imately 335° with a 30° to 70° dip to the southwest was mapped. Minor shears parallel to this set were found near \·J~1-4. 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 Set I and III joints. 5-9 I I • Discontinuous fracture zones were found to parallel Set II joints. No major structures w~re found associ a ted ~;i th Sets I I or IV. The Susi tna River appears to be joint-controlled at the t~atana dams it e. In the upstream area, the river· parallels Set II. 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 shea~ and fracture zones related to Set I joints. ( i i -1) Shears, Fracture Zones, and Alteration Zones Ttis section def1nes and discusses shears, fracture zones, and alteration zones and combinations of these features which are the shear/fracture zones and shear/alteration zones mapped at the Watana site, _Symbols denoting these features on the geologic sections (Figures 5.3 through 5.7) are: shears (S), fracture zones (F), alteration zones (~), shear/alteration zones (S, A}, and shear/fracture zones (S, F). For the most part, these features are 1 es s than 10 feet wide.. Where more than 10 feet wide, both boundaries have been delineated on the geologic map (Figure 5.2) and geologic sections. The individual characteristics of shears, fracture zones, and alteration zones are described b?llow, while Subsection (iv) discusses the specific areas in which these structures occur. -Shears Shears are defined as a surface or zone of rock fracture along which there has been measurable displacement or is characterized by breccia, gouge) and/or-slickensides indicating relative movement. Three types of shears are found at the \~atana site. The first type, which is found only in the diorite, is called healed shear and/or healed breccia.. This type of shear consists of a .diorite breccia hea 1 ed v1ithi n 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 fr·agments, which are observed in both outcrop and cere borings, are fresh and ,hard to very hard. A photo- graph of·a 1 to 2 foot wide healed she_ared zone is shown in the 1980-81 Geotechnical Report \1). The contacts, although irregular, are tight and unfractured. In out- crops, healed shears and breccia range from 1 ess than l inch to about 1. 5 fee:t. Up to one foot offsets of these features have Geen observed where they cross fe1 sic dikes. Two general orientations were found for this type of shear: 305° dipping 45 o to 70° northeast, and 300° dipping 65° southwest. 5-10 I ·I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I He a 1 ed shears and breccias were found in virtually a 11 boreholes. In all cases, the zone was found to be compe- tent with high RQDs and high core recoveries. The larg- est healed shear was up to 140 feet thick in COE DH-11. No carrel at ion caul d be made between the healed shears and breccias noted in the cores and the surface expo- sures. Ther·efore, these features were not delineated on the site geologic map. These features are interpreted to be emp 1 a cement type shears which formed dlfri ng the 1 ast phases of plutonic activity when the magma was in a semi- solid state .. The sec10nd type of shear found at the site is common to a·ll rock types and consists of unhea 1 ed breccia and/ or gouge. The breccia consists vf coarse to fine sand-size rock fragments in a silt or clay matrix.. Gouge is gene~ rally 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 10 feet, but are generally less than 1 foot. Carbonate and chlorite mineralization are commonly associ a ted with these shears.. Some shears a~e partially to completely filled with carbonate. Slickensides are found in many shears and occur on both the carbonate and chlorite surfaces. The shears are most often associated with fracture and alteration zones. When found in association with these zones, they have been referred to as shear/fracture and shear/alteration zones. A photograph of a typical shear within a fracture .zone is shown on Figure 5.9. These zones will be discus- sed in more detail in the Fracture Zone and Alteration Zone subsections. The third type of shear, unlike the two former types, may not be tectonic in origin but may be due to slumping of large blocks. These features are found in "The Fins 11 area and are discussed in Section 5.2 (c). -Fracture Zones Fracture zones are. areas of very closely to closely spac- ed (less than 1 foot) jointed rock where no apparent re- 1 ati ve movement has occurred. Fracture zones are common to all rock types and are found in both outcrop and bore- he 1 es. Fracture zones in outcrop were found to range from 6 inches up to 30 feet in width but are generally less than 10 feet wide. I.. 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 boreho 1 es and outcrop, the fracture zones are less than 5 feet wide. Where exposed, they are easily eroded and form topograph- ic lows or gullies, \tJhich 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. 5-11 I l • -Alteration Zones Alteration zones are areas where hydrothermal solutions have caused the chemical breakdown of the feldspars and mafic minerals. The common products of alteration are kaolinitic 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 a 1 terat ion zones is from thE:. boreholes. Alteration zones are rarely seen in outcrop ~ecause ~ 1 ike the fr actur' zones, they are re 1 a- tively easily eroded and tend to · ..... 1m gulliet, which sub- sequently become filled with talus. Alteration zones are exposed on the surface on the north bank .; n 11 The Fi ns 11 and in one outcrop at river l eve 1 near ~i1e dam center- line. The degree of alteration is highly variable rang- ing from slight, where the feldspars show disco.)ration, to complete where the feldspars and maf)cs are completely altered to c1ay 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, Reference 1). The slightly altered zones have approximately 10 to 25 per- cent of the feldspars stained or altered to clay. In comp 1 ete ly a 1 tered diorite, the rock is n 1 eached to whitish grc..y or very light yellowish gray.. The rock fabric is preserved; however, the material is soft and friable. These completely altered zo~1es are uncommon, and when enccuntered, are generally 1 to 2 feet wide. Most alteratiun zones found in the boreholes are slightly t"o woderately altered. These zones are moderately hard with some thin soft zones. A pho.J.:>graph of an alteration zone within 11 The Fins" is shown on Figure 5.10 .. Widths of these alteration zones range up to 10 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 GF 8 (Figure 5o4). Several ~hear/ alteration zones are exposed in ''The Fins•• and range up to 10 feet wide. The carbonate, which is a1so associated with the altera- tion zones, occurs as veins or joint filling generally up to 0.5 inch thick. Occasionally, sulphide mineralization 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 (less than2 inches) shears are associated with the alteration zones 5-12 I I I I I I • I I I I I I I I I I I I I I I • I I I I I I I I I . I I I I I I I ., n (Appendi !< B, Reference 1). RQDs are generally 1 ow, be- cause only fresh to slightly altered rock is considered in tc.k i ng RQD measurements. Core recovery is generally more than 90 percent within the alteration zones. The transition from fresh to a 1 tered rock is gradati ona 1, generally occurring over less than 1 foot. (iv) Si9nificant Geologic Features The ~~atana damsite has been divided into several broad areas of significant geologic features ltihich consist of shears, fracture zones, alteration zones, and/or combina- tions of these features. Two of these areas, initially mapped by the COE (27) are called 11 The Fins" and "Finger- buster11 (Figure 5. 2). Areas or individual structures con- sidered to warrant detailed discussion have been identified on Figure 5 .. 2 by letters GF 1 through GF 8 and are discus- sed individually below. Seismic line data from this inves- tigation is found in Appendix c. Borehole and seismic data from the 1980-)81 investigation are in the 1980-81 Geotech- nical Report\1 • -Geo 1 og_i c Feature GF 1 -11 The Fins 11 Geologi~ Feature GF 1 is discussed in Section 5.2- Upstream Cofferdam and Diversion Portals Location. Geologic Feature GF 2 GF 2 (Figure 5. 2) is approximately 70 to 100 feet wide and consists of northwest-southeast trending fracture zones with minor shears.. On the south bank, GF 2 is coincident with a deep, talus-filled gully. Outcrops on eit11er side of the gully are very closely jointed (Set I). Oi ps are vert i ca 1 or steeply dipping to the north- east • On the r0rth bank, GF 2 lies in a deep gully vlhich ex- tends to about ~levation 1850 and probably under an adja- cent ta 1 us-fi 11 ed gully to the west. Set I joints form the walls of the gully and are very close to closely spaced and often open.. No bedrock was exposed on the gully floor. No sign of hydrothermal alteration was found on the outcrops. Below Elevation 2200, seismic lines SL81-15X and SL82-5, SL82-10, SL82-11, and SL82-13 (Figure 3.1) indicate low seismic velocity bedrock, 9,000 to 13,000 fps, often overlying a high seismic bedrock velocity, 20,000 to 22,000 fps. The 9,000 fps bedrock along line SL82-10 is 5-13 up to 300 feet thick. On seismic lines SW-3 anj SL82-5, higher bedrock seismic velocities, 17,400 to 18,500 fps, were found over the projection of GF 2, which indicates the feature may be discontinuous to the north..-;est. GF 2 is likely to be encountered in the excavation for the intake approach channel, the power intake, and the diversion tunnels (Figures 5.4 and 5.6). -Geologic Feature GF 3 GF 3 is an area approxim?~;ly 1,200 to 1,500 feet wide on both the north and sour' 1anks a.nd is bounded by geologic features GF 2 and GF 4 \• i gur'e 5. 2).. ,The area is charac- terized by minor shears ~and fracture zones genera 1ly 1 ess than 6 feet wide. Outcrop exposure is excellent on the south l)ank, and although 1 imited on the north bank, a good cross section is 'exposed (Figur8 5.1). Figur·e f'l.2 shows the 1ocation of the shears and fracture zones mapped. Most structures trend northwestward with hi 9h- angle northeast to vertica'l dips.. Other structures stri~'e northeast and north, parallel to joint Sets ~) and I I I. A 20-foot-\·Ji de fracture zone vms mapped in a deep gully on the south bank. This is probably continuous beneatn the river and aligns with a similar structure on the north bank. Thi~ fracture zone probably continues north- westward para 11 e 1 ~o Gf 2 through the same l ov1 s.ei smi c ve 1 ocity zones. A 30-foot-wide bedrock lovt on SL82-5 lies alo~g the trend of the feature. A 2. 5-foot-wi de vertical shear \.ln the south bank viaS tentatively correlated with a deep, narrow gully along its trend on the nort;a bank. No other structures could be correlated across the river. On the north bank, a broad talus slope belo\'1 Elevation 1650 is approximately 400 feet wide and may be the re~ult of intersecting northeast ~,.'nd northwest trending struc- tu·"es in this df'ea. Seismic line SL82-12, which crosses GF 3 on the south bank at about Elevation 2050, indicates moderately frac- tured to fresh bedrock across the feature. On the north bank, conditions are similar except at approximately Elevat1on 1650 where SL82-11 shows highly fractured bed- rock (9s-OOO to 11,200 fps) to depths up to VsO feet, but generally 60 feet, overlying high seismic velocity bed rock (20,000 fps). The relation of this feature with civi, st~u~tures, such as the diversion tunnel, power intake structure, 5-14 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I :; penstocks, and powerhouse will require further investiga- tion in the design phase. -Geologic Feature GF 4 GF 4 consists of t\'/O shear/fracture zones (GF 4A and GF 4B), each about 10 feet wide (Figure 5.2). The over- all 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, I I and I I I. All joints are heavily carbonate coated. Where mapped, GF 4A 'tlas found moderately wea- thered \vith possible alteration. Seismic velocities ir. this area (SL80-3) are lower (15,000 fps) than the usual 18,000 to 20,000 fps velocities measured in less fractur- ed diorite. A bedrock low is noted on SL82-12 where GF 4 projects across. GF 4A and GF 4B have been projected across the river to carrels_ with two fracture zones mapped between Eleva- tions 1650 and 1750. These fracture zones are also in a deep gully e GF 4A has been tentatively carrel atP.d with the shears, fra.cture zones, and alteration zones found in borehole BH-3 (Figure 5.3) between borehole depths 414.4 and 622 .. 4 feet. These zones are s1ight1y to moderately altered and generally moderately hard~ though locally soft and friable in the shears. RQOs between borehole depths 47 4 and 530 feet are 0 percent because of the moderate alteration. !'hroughout the rest of the zone, RQOS are 90 to 100 percent with permeabilities generally 10-em/sec. Many of the joints are hea 1 ed by car- bonate. The correlJtion of the zones in BH-3 with GF 4A has been based on the assumption that the zones are tren- ding northwestward. This assumption is supported by the fact that this fracture zone would have been ~ntersected in either BH-4 or OH-11 if it had had an east-west or a north-south strike. GF 4B has been carrel ated with a shear /fracture zone and alteration zone in DH-11 (Figure 5.3) at bGrehole depth 189.0 to 197.7 feet. The fracture zone is iron oxide stained. The upper three feet of the zone are hydrother- mally altered and contain 0.2 feet of clay gouge and breccia. Permeabilit~es in this zone a3e high, typically ranging between 10-em/sec to 10-em/sec. Most joints -are coated with sandy silt/clay and minor carbo- nate. The GF 4 strut:ture was correlated with lower seismic ve- locity zones on SL82-5 and SL82-9 on the north bank. On SL82-9 ~ the structure corresponds to a bedrock seismic 5-15 v~locity change from 20,000 to 16,500 fps and a small bedrock surface depression. On SL82-5, GF 4A and 4B occur within an area of moderately low seismic velocity (13,400 fps); however, at GF 4B, there is approximately 110 feet of highly ft"actured, 1 ow ve 1 oci ty · ( 9, 000 fps) bedrock overlying the hi1her velocity bedrock. On SL82-14, which is 400-500 f8et northwest of and subpara1- 1 el to SL82-5, there is no strong evidence for GF 4A .. GF 48 correlates with a change in slope of the bedrock surface.· The projection of the GF 4A and GF 4B structures would intersect the proposed diversion tunnels (~igure 5.2) at a high angle and waul d intersect the west end of the powerhouse (Figure 5.3). -Geologic Feature GF 5 GF 5 is located near the proposed dam centerline and con- sists of fracture zones and minor s'"'ears (F·igures 5.2 and 5.4). The area is approximately Gj 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 ~"i ver fa 11 s within a deep gully bound on the downstream side by a 75-foot-hi gh diorite c 1 iff. Two northwest trending fracture zones 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 little topo- graphic expression of these features higher on the abut- ment, it has been correlated with several ~hear and frac- ture zones intersected in borehole DH-9 (Figure 5.3), and interpreted on SL82-5, SL82-9, and SL82-14. 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 l~w, with an average of 1 57 percent. Perme~bilities are generally between 10-em/sec and 10-em/sec and decrease with depth. On SW-2, SL82-5, SL82-9, and SL82-14, GF 5 carre- l ates with sharp drops in the bedrock surface and with low seismic velocity bedrock (7,500 to 14,500 fps). On SL82-5, approximately 80 feet of highly fractured bedrock (7,500 fps) overlie 13:~400 fps bedrock. No lvw velocity zones were encountered alo~g SL80-2. On the south bank, the GF 5 structure is correlated to a 10-foot-wide fracture zone at river level and a series of minor northwest-trending shears between Elevation 1650 and 1850. Farther up the slope, it is correlated with a moderately low (14,000 to 15,000 fps) seismic velocity zone along SL82-12 and SL80-3, and a bedrock depressio1n found in bor~hole DH-25 and on SL82-12 (Figure 5.7). In this area, overburden thickens from 10 or 15 feet to nearly 80 feet. 5-16 I I I I I I I I I I I I I I I ') I I I I I I I I I I I I I I I I I I I I I I I ~. . ~ ·. . : ;~ . . . _':,_;;' .· : ~ .. On the north bank, GF 5 may 1 ike ly inter sect the diver- sion and tailrace tunnels, and the excavations for the main spillway. -Geologic Feature GF 6 GF ·6 -is characterized by north-south trending shears, fracture zones, and open joints; east-west trending open joints; and northwest trending shears (Figures 5.2 and 5. 5). These features are exposed in deep gullies {n the high rock cliff face on the south side of the river (Fig- ure 5.11). The north-south shears have up to 2.5 feet of gouge. Open joints a 1 ong this trend generally d ~I) at about 80° to the east and are up to several feet w'de. East-\'lest t·rending joints dip 70° to 80° north tow.1rds the river. The intersection of these joint sets has re- sulted 1n block slumping.. Details of northwest trending shears in GF 6 ar·e discussed in Section 5.3 (c). It is likely that north-south shears and fracture zones in GF 6 correlate with those in GF 7. GF 6 1 i es above the downstream cofferdam. 51 umpi ng of blocks in GF 6 may affect the integrity of this abut- ment. -Geologic Feature GF 7 -"Fingerbuster" Geologic Feature GF 7 is discussed in Section 5.3 -Down- sL~eam Cofferdam and Portal Locations. -Geologic Feature GF 8 GF 8 is a wide (approximately 400 feet) northwest trend- ing structure on the south bank of the river which con- sists primarily of alteration zones but also includes shear and fracture zones. (Figure 5.2). This area was delineated during the 1981 field season during the inves- tigation for a possible underground powerhouse location on the south bank. As a result of the. scarcity of bedrock exposure in this area, all geologjc interpretation has been based on seis- mic refract~on surveys and drilling. In 1981, an 1,800-- foot seismic line (s;_a1-21) \<Jas shot along a northeast- southwest trend across the south bank (Figure 3 .. 1). Pt zone about 1,100 feet long of low seismic velocity in bedrock was found .. Velocities were about 12,000 fps in this zone and 18,000 fps in the adjacent zones on each side. Poor quality rock was confirmed by BH-12 Which was drilled to the southeast to intersect this structure 5-17 (Figure 5.4).. At about Elevation 1700~ the boring en- countered a nearly cant i nuous zone of altered diorite with minor shea""s. Alteration is genet"'ally slight but includes zones of moderate to severe alteration._ Shears are less than 6 inches wide. Joints are generally close- ly spaced and healed with carbonate. Chlorite is found on some joint surfaces. The trend and dip of this structure NaS based on correla- tion between SL81-21, SW-1, BH-12, and DH-28. DH-28 was drilled vertically to a depth of 125.2 feet in andesite porphyry. The rock in the boring is slightly to rnoder .. ately altered and moderately hard. Joints are very closely to closely spaced and iron oxide stained through- out. 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 5.7).. East of DH-28, SW-1 shows zones of alternating high (17~500 to 20,000 fps) and low (12,000 to 13,000 fps) sei.smic ve:locity bedrock. No evidence of shearing or alteration was found in BH-8, DH-12, DH-23, or DH-24, or in any outcrops on the south bank (Figure 5.4). "(his observation served to limit the northward extent of GF 8. In defining the t~end 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 1 ow to high bedrock velocity on SL81-21.. The southwest contact was assumed to be 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 70° to the southwest (Figure 5 .. 4). 5.2 -Upstream Cofferdam and Diversion Portals Location (a) Overburden and Ground Water ( . ) ~ 1 Introduction This section discusses the overburden or sur~icia1 deposits in the vicinity of the upstream diversion portal and up- stream cofferdam location. The extent and type of bedrock and surficial deposits in the upstream diversion area are shown on a geologic map and sections (Figures 5.12 and 5.13). Material types in this area, which consist of talus and alluvium, have been investigated by geologi.c mapping and seismic refraction surveys (Figure 3.1) and are discus- sed below. 5-18 I I I I I .I I I I I I I I I I I I I I I I I I a I I I I I I I I I I I I. I I (; ( i i) A 11 uvi urn The extent of alluvium in the upstream portal and cofferdam area is shown in Figures 5.12 and 5.13. The alluvium occurs primarily at or be1ow river ~evel, however, pockets or thin layers are founu above river level. On the north bank, a thin pocket of mixed a 11 uvi urn and ta 1'!5 was mapped near the proposed diversion tunnel number 1 portal. On the south bank, a layer of alluvial material covers a saddle (possibly an old Susitna River channel) between two bedrock highs. Alluvium in this area has been divided into two types .. Type 1 alluvium occurs at or below the level of the Susitna River and Type 2, which principally occurs on the south bank above river 1 eve 1. Type 1 materia 1 is exposed during low flows ~n a gravel bar on the south bank. The surface of this bar consists of a boulder pavement. However, shal- low pits dug in this.area show the material to be a sandy gravel, \'/ell graded with fine gravel to boulders up to 4 feet in diameter. Grain size, however, is generally limi- ted from 6 to 12 inches. Cobbles are subrounded to rOL'nd- ed. Th2 sand and silt matrix between the gravel fragments make up ·from 5 to 15 percent of the gravel bar. Cobbles greater than 4 inches are mostly medium grained grdnitic rocks, whi 1 e those 1 ess than 4 inches are primarily fine grained volcanic, metamorphic and sedimentary rocks. More than 95 percent of the rock fragments are fresh and hard with the remainder being weathered and friable. Downstream of the proposed cofferdam centerline, the surfi- cial alluvium appears to be finer grained with an increase in "*:he amount of sand. Average grave 1 size is 2 to 6 inches with 15 to 25 percent coarse to fine sand. Layers and/or 1 enses of sand up to 1. 5 feet thick are found in this area. The sand is uniformly graded and fine grained. Some of this sand appears to be derived from Type 2 a 11 u- vium which occurs on the south bank above river level. Type 2 a 11 uvi urn is exposed at the river edge and in scat- tered outcrops further upslope. Upstream of the cofferdam centerline, Type 2 alluvium is primarily well graded, sandy gravel with fragments ranging up to 2 feet but generally from 4 to 6 inches. Approximately 10 to 20 percent of the material is sand. Most fragments are iron oxide stained .. About 5 to 10 percent of the fragments, primarily the meta ... morphic rocks, are severely weathered. Downstream of the cofferdam centerline, the material is exposed at river level where it is washing out beneath the tundra mat and at about Elevation 1500 where it is exposed near two ground .water springs and in a seismic line shot hole. In these areas, the materials are disturbed so that the exact litho- logy is uncertain. At river level, the material is 5-19 primarily sand with scattered bou1ders to 4· feet. At the shot hole for SL81-5, 2 feet of talus overlies a yellowish brown sandy gravel alluvium. Fragments range up to 3 inches but are generally 1 inch. Coarse to fine sand com- prises 20 to 30 percent of the alluvium. The remaining 5 to 10 percent of the material is non-plastic fines. The alluvial thicknesses in the upstreaQ diversion area has been estimated from seismic refraction surveys (seismic lines SL81-4, SL81-5, and SL82-15, Figure 3.1). Several interpretations of this seismic data can be made thereby affecting the determination of river allu~ium thickness in this area (Appendix J, Reference 1). Different interpreta- tions of the material with velocities in the range of 12,000 to 14,000 fps can be made. These velocities could reflect either fractured/weathered bedrock, or dense/frozen alluvium. River morphology does not readily support the \veathered/fractured rock interpretation. Therefore, the latter interpretation has been used in the current inter- pretation as shown on geologic section UP-3. However, fur- ther confirmation.of this will be required. Using this interpretation, alluvium thicknesses beneath the upstream cofferdam area would be a maximum of 90 ·~o 100 feet. T0 the west side of the river, alluvium is assumed to terminate abruptly against near-vertical bedrock. On the east side of the river, the alluvium thins gradually to 20 feet at river edge and then thins abruptly upslope to about 5 feet on seismic: line SL82-15. Above river level on the south bank, alluvi.al velocities decrease from 5,000 to 2, 000 fps, i ndi cati ng they are unsaturated above river 1 evel. The contact between the all uvi urn and ta 1 us is shown on Figure 5 .. 12 .. The contact is approximate and is based on: (a) the lowest extent of continuous talus material; and (b) the associated break in the slope which generally occurs between the talus and alluvium. This contact is nearly coincident with the toe planned of the upstream cofferdam. (iii) Talus The extent of talus in the portal and cofferdam area is shown on Figures 5.12 and 5.13. Talus occurs on the slopes above the portal locations along the north bank and also on the south bank downstream of the upstream cofferdam lOca- tion. Talus consists of angular to subangular blocks of diorite with some diorite porphyry. On the north bank~ talus ranges from sand-size grains to blocks up to 10 feet in diameter. Average size varies across the area but is generally 1-2 feet" The 1 argest b 1 ocks at·e found at the base of the wide sinuous gully above the proposed diversion tunnel number 2 portal. 5-20 I I I I· I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ( i v) ..... On the south bank, downstream of the toe cf the cofferdam, talus ranges up to 5 feet in diameter at river level but is generally 6 to 8 inches. Slumps in the talus occur above Elevation 1500 on the south bank (Figure 5.12) where a slump scarp ~~ exposed for approximately 100 feet extending in an appro.timate east-west direction.. The hei 9.ht of the feature is 20 to 30 feet. The toe of the slump corresponds with the talus/alluvium contact and so would partially underlie the downstream toe of the cofferdam~ The talus in this area ranges up to 3 feet but generally is from 1 to 2 feet fn size. Talus areas have been divided into two types. Talus 1 is primarily well exposed areas, less then 50 percent vegeta- ted, where the talus is actively or sem·f-actively moving downslope. These areas are mainly within the gullies in 11 Th e Fins, 11 part i cu 1 ar ly in the area of the diversion tu nne 1 number 2 porta 1. · Tal us 2 is densely vegetated areas of inactive talus and more stable slopes. Talus· 2 occurs: (a) on the south bank downstream of the cofferdam location; and (b) on the north bank on ridges within "The Fins 11 above the main area of bedrock ou~crops; and (c) along the diver- sion tunnel rout~ and downstream of the cofferdam location (Figure 5.12). :hickness of the talus deposits are not known with any cer- tainty; bu"t. they would be expected to be variable through- out the area. On the south bank, seismic line SL82-15 (Appendix C) indicates from 5 to 35 feet of 2,000 fps mate- rial in a Talus 2 area. Talus thickness at the location of the upstream cofferdam is likely to be about 5 feet. On the north bank, Talus 1 deposits are generally less than 5 feet thick. An exception to this would be in the talus cones formed at the base of the gullies at river level, particularly in the diversion tunnel number 2 portal area where talus accumulations may be from 10 to 20 feet thick. The extent of Talus 1 below river level is not known, but due to its generally large size and blocky nature, it may be prevalent. Talus in the diversion tunnel number 1 por- tal area is negligible. Thickness of Talus 2 deposits on the north bank is also unknown, but based on steepness of the slopes and bearock outcrop, thickness is estimated to be less than 10 feet. Ground Watet" \ Ground water conditions in the upstre m diversion area are poorly defined, being based only from mapping observations. However, it is expected that ground water con1di}tions are as described in the 1980-81 Geotechnical Report\1 • 5-21 (b) (c) On the north bank, ground water is principally confined to fractures anu joints within the bedrock.. Ground water seeps were observed at two locations in the diversion area. The greatest flow was observed in the 30-foot-wide gully at the northwest corner of the geologic map (Figure 5,.12). Flow was estimated at 10 gallons per minute ( gpm) in August, 1982. A second seep (Figure 5.12), occurs adjacent to a shear zone (geologic feature GF 1G) at about Elevation 1650. Water flow was estimated to be less than 1 gpm. On the south bank, ground water seeps were found in alluvi- um in the :trea of the proposed cofferdam. Two springs at about Elevation 1500 were flowing at about 1 gpm.. At the break in s 1 ope from the river bank to the gravel bar, two other seeps wer--e observed with gr·ound water flow of about 5 gpm. The seeps on the south abutment may be the result of a perched v1ater tab 1 e on permafrost. bedrock Lithology The bedrock lithology in the upstream diversion area is primarily diorite to quartz diorite which has been intruded by fe 1 sic and mafic dikes.. A detailed description of these t"ock types is in Section 5.1. The extent of these rock types is shm1n on Figures 5.12 and 5.13. Bedrock in this area is generally fresh to slightly weathered and very hard to hard. Zones of hydrothermally altered diorite are found upstream of the porta1 location and are discussed in the following section. Bedrock Structure (i) Introduction (ii) This section discusses the structural geology of the up- stream cofferdam and diversion porta 1 area of the Hat ana damsi te and how it re 1 ates to these proposed structures. This section is presented in two subsections: joints and significant geologic features. Significant geologic fea-. tures include shears, fracture zones, and a1 terati on zones as defined in Section 5.1 (c). Joints Three of the four joint sets mapped at the site and descri- bed in Section 5.1 (c) are found in the upstream and portal area. A plot of the joints in this area are shown on Figure 5.12. Table 5.3 1 ists the joint characteristics of tr: s area. 5-22 • ·a I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Joint Set I, as throughout the damsite, is the most promi- nent set. Set I joints in this portal area are primarily part of the I a subset which trends from 285° to 345° and average~ 325°. Dips vary from 60° northeast to ~oo south- west but are mostly near-vertical to vertical. Joint spac- ing is variable from less than 1 inch in shear and frac- ture zones to greater than 5 feet. Average spacing is 1 to 2 feet. Exposures in the deep gullies cross cutting this area show evidence of rapidly increasing joint spacing with depth. Joint surfaces are planar and smooth to s1 i ghtly rough. Set I joints are parallel to the major shear~ frac- ture.9 and alteration zones which occur in 11 The Fins • ., Set II joints are generally as prominent as Set I joints in this area. The Set II joints strike northeastward averag- ing 042° with predominantly near-vertical dips to the northwest. Joint spacing is similar to Set I, gen~rally 1 to 2 feet, and like Set I, increase with depth. Joint sur- f~ces are planar to slightly curved and smooth to slightly rouyh. Many Set II joints are open with related slumping. Discontinuous fracture zones were found which par·allel Set II joints. These are discussed below. Set I I I joints are not observed in the upstream porta 1 area. Set IV joints are low-angle joints with variable orienta- tions. The strongest trend is northeast at 045°. Dips are generally from 10° northwest to 10° southeast. Set IV joints are d i scant i nuous and genera 11y occur only in the upper 30 to 40 feet of rock. These joints are not found in the deeper parts of the gullies which crosscut the upstream portal area. Shears labelled GF 1N on Figure 5.12 are parallel to subpar~llel to the Set IV joints. These &ea- tures generally strike from northwest to north and dip eastward toward the Susitna River from 11 o to 42°. These features appear to be older bedrock slumps partially healed with carbonate, and are only found above Elevation 1675 ... In summary, major shears and alteration zones are parallel to the northwest trending Set 1 joints. Discontinuous fracture zones are parallel to Set II joints. Spacing of Sets I and II joints increase with depth. Set IV joints are primarily near surface features. (iii) Significant Geologic Features The upstream diversion area is 1 ocated in proxjmitY to the geologic feature referred to as 11 The Fins"{27 J. uThe Fins 11 is a seri2s of deep gullies separated by intact rock bands or ribs from 5 to 50 feet wide. For the purpose of 5-23 OJ this report, 11 The Fins" has been designated as geologic feature t.;F 1 ·to conform to the system of designating signi- ficant geologic features (Section 5.1). 11 The Fins 11 {GF 1) is located approximately 2200 feet up- stream of the main darn center·l i ne in the area of the pro- posed upstream cofferdam · f1d diversion portals. The geolo- gic map and sections of·th~ damsite (Figures 5.2, 5.4, and 5.6) shows the relation of this feature to civil arrange- ments and othe~ geologic features. A more detailed map and sections of "The Fins 11 structure are shown on Figures 5.12 and 5.13. Two photographs of "The Fi nsll are included as Figures 5.14 and 5 .. 15. Shears, fracture zones, and altera- tion zones within "The Fins 11 have been designated GF lA through GF lP for discussion purposes. Based on more detailed mapping in 1982, a significant rein- terpretation of 11 Th e. Fi nsn structure has been made. Recon- naissance mapping in 1980 and 1981 indicated the presence of numerous sue)ar fracture z_ones and a 1 terat·i on zones with- in this area \l • It was assumed at that time that the deep gullies (figure 5.14 and 5.15) wit))in uThe Fins" were under 1 a in by the major di scant i nuiti es. In 1982, these geologic features were mapped in greater detail. This mapping shows that most structural discontinuties crosscut the gu11ies rather than lie within them. 11 The Fi ns 11 is an area of major shears, fracture zones, and alteration zones of· various orientations. The strongest trend of these discontinuities is northwest-southeast, parallel to Set I, and northeast-southwest parallel to Set I I. Minor shears were found trending at various orient a- t ions. -Northwest Trending Structures Northwest trending structures consist of shears, fracture zones and alteration zones. These features strike from 310° to 345° and generally have high-angle to vertical dips. Three major shear/alteration zones (GF 1B, lC and IE) were mapped upstream of the location for the diver"!" sion tunnel number 2 portal. These zones consist of hydrothermally altered diorite from 5 to 10 feet wide. The rock in these zones is yellowish orange, severely altered and medium hard to soft and friable. Very close to close spaced shears are found parallel to the a1tera- t ion zone. Shears range from 1 ess than 1 inch up to 1 foot. Gouge is generally a slightly to moderately plas- tic sandy clay. Blocks of less altered and unsheared diorite are often found within the alteration zones •. 5-24 I I I I I I I I I I I I I I I I I I I I I I 11 Ill I I I I I I I I I I I I I I I Carbonate veins ranging from· 0.5 to 8 inches occur within the alteration zones. These veins botfl parallel and cross cut the zones. Carbonate veins are fractured, but no offsets wer~ noted. Figure 5.10 is a photograph of GF 1C near river l eve 1 , shmvi ng a carbonate vein within an a 1 terat ion zone. Above this outcrop at about Eleva- tion 1550, a 4 inch wide light gray, fine to medium grained felsic dike cross cuts the alteration zone. The dike is fresh to slightly weathered and very closely fractured. The dike is truncated by a 2-to 3-i nch-wi de shear. Of these three alteration zones, only GF 1C is 1 ikely to be encountered in .a porta 1 excavation (Figure 5.13) .. The area of the diversion portal excavations is charac- terized by a series of parallel to subparallel shears and fracture zones (GF 1F to 1J, and GF lL). These struc- tures genera 11y trend from 325° to 340° wni ch is sub- paralle"' to the strike of the alteration zones .. Dip:5 vary within the s arne zone, but are usua 1ly greater thar- 800. Widths of these zones range from 1 to 10 feet and are also variable within the same zones as seen with GF 1G and GF 1I. GF 1G increases in width with depth from 1 to 2 feet at Elevation 1700 to 6 feet at the di- version tunnel number 1 portal area at Elevation 1500. Conversely, GF 11 decreases in \'iidth with depth, varying from about 5 feet where it crosses above the diversion tunnel routes, to 1.5 feet at river level in the coffer- dam area. It should be anticipated that other shear and fracture zones may vary in width laterally and vertical- ly. Shears such as GF lG, GF 11 and GF 1J are primarily zones of very closely spaced JOints which include thinner zones (less than 1 foot) of breccia and gouge. The shear planes genEr·ally form th0 boundary of the zone. GF ll, which consists of two para 11 el fracture zones, 10 feet and 1.5 feet wide, is presently the major source of talus for the large sinuous gully that it crosses at about Elevation 1800. Ta 1 us is derived from the area of intersection of GF ll and GF lJ. This area is highly fractured with many open joints and 1 oose rock. GF ll forms a topographic low which cross cuts the main gullies at a high angle. This feature aligns with a deep gully and fracture zone on the south bank. This feature as well as those mentioned above, are expected to be encoun- tered in the tunnels. They intersect the tunnel align- ment favorably at an acute angle. These structures also pass beneath the cofferdam location. 5-25 -No':'theast Trending Structures Northeast trending structures in the upstream portal area were mapped to the southwest of the proposed excavation area., These four features (GF 1M) are fracture zones less than 6 feet wide with dips ranging from 62° south- east to vertical. These features tend to form gullies and/or bedrock faces parallel to the trend of the valley. GF 1M structures were mapped only in the southwest por:.. tion of the map area (Figure 5 •. 12). A·~though bedrock is continuously exposed along the projected trend of these features, no trace of the GF 1M structures was found northeast of Gf lL so it is assumed that they are discon- tinuous. It is unlikely that these featu .... es would be encountered in the porta 1 excavations, ho\'/ever, simi 1 ar structures to the northwest may be encountered in the diversion tunnels. -Miscellaneous Structures In addition to the northeast -and. northwest trending str'lCtures discussed above, there are numerous minor shears mapped in 11 The Fins" --~ea. Two north-south trend- ing shears, GF lF were ma~ dd upstream of the diversion portal area. The shears are 1 and 3 feet \'tide and dip west at approximat,:.1y 60°.. Slickensides f''r! a carbonate· coating indicate ail oblique sense of moveme"t. No shears of this orientation were found in the diversion porta 1 area. A series of low angle shears (GF lN, Figures 5.12 and 5.13) were mapped primarily in an area above Elevation 1675 aiong the proposed diversion tunnel alignment. These features strike northeast and northwest, and dip from 11 o to 42° southeast and northeast, respectively .. Dips are toward the river. These structures consist pri- marily of hi ghl,y fractured rock from less than 1 foot to 6 feet in width. The struci.'Jral planes are generally curved to irregular· in shape. Unlike mosc fracture zones, the fractured rock in the GF lN structures is tight, hard, and partially healed with carbonate cement. A shear at Elevation 1800, which dips at 42° east, has offset a felsic dike by 16 inches. There is no gouge or breccia associated with this shear. However, there is a 3 foot fracture zone on either side of the shear plane~ fhe amount of offset could not be determined on the ·remainder of the GF lN shears; however, many joints are dj sconti nuous across the structure, i ndi cati ng movement. The exception to this are the Set I joints which crosscut the shears with no offset. The continuity of the GF lN shears is uncertain; none could be traced for more than about 10 to 30 fee·c. due to 5-26 I I I I I I I I I I I I I I I I I I I. I I I I I I II fl I I I I I talus·and vegetative cover. None.were mapped below Ele- vation 1675 feet or upst~-"'am of the diversion tunnel number 2 alignment. The~c eatures dip towards the por- tal cut (Secion UP-2, Figure 5.13) and although partially healed, may become unstable during excavation. -Extent of 11 The Fins 11 The overa·ll trend of 11 The Fins" is 300° to 310°. The extension of this feature to the nortr·.-~est is ir1ferred from seismic refraction lines SL81-15, SL81-15X, and SW-3 which show low seismic velocities (10,000 to 12,700 fps) in bedrock as well as low bedrock elevation along the projection of 11 The Fins" (Figure 5.4). In contrast, the bedrock seismic velocity southwest of this feature is greater than 17,000 fps (Appendix C, Reference 1). Beyond the seismic 1 i nes, 11 The Fi ns 11 has been inferred to trend along a topographic low (Figure 6.7) •. Altered rock found in COE boreholes DR-18, DR-19, and DR-20 in the Watana Relict Channel may also have drilled into this feature (Figure 3.2). The topographic low projects to Ts us en a Creek, where, along the northwest bank, an a 1 ter- ed and sheared outcrop of granodiorite is exposed. This outcrop exposure is approximately 325 feet wide, and is characterized by northwest, north-south, and east-west trending shears. The cont·inuation of 11 The FinS 11 to the southeast beyond the south bank of the Susitna River is uncertain. On the south bank across from("-)lhe Fins 11 , there is a topographic low in Quarry Site L 1 , as well as shears and frac- ture zones which align with the GF 1 structures. Seismic 1 ine SL82-15 (Figure 3.1), which crosses the trend of 11 The Fins", shows a bedrock depression and low velocity bedrock (7, 700 fps) {Appendix C). This area is the inferred locatiun of uThe Fins .. 11 Beyond this area, no outcrops or topographic trends could be corre 1 ated to this feature. 5.3 -Downstream Cofferdam and Portals Location (a) Overburden and Ground Water (i) Introduction This section discusses the overburdt..dsurficial deposits in the vicinity of the proposed downstream diversion portals, tail race porta 1, and spillway flip-bucket. The extent and type of bedrock and surficial deposits in this area are shown on a geologic map and sections (Figures 5.16 and 5.17). Sections are drawn through proposed 1 ocat.i ons for 5-27 ( i i) diversion tunnel number 2, tailrace tunnel~ spilh'lay flip:- Bucket and along the center 1 i ne of the downstream coffer- dam. This area has been investigated by geologic. mapping, seismic refraction surveys, and borings. Borehole and seismic survey line locations are shown on Figure 3.1. A lluvi urn The extent of all uvi urn in this area is sho\'m on Figures 5.16 and 5.17. Alluvium occurs beneath the river and also locally along the river banks. On the north bank, an allu- vial terrace extends upstream from the diversion tunnel number 1 porta 1 area to beyond the downstream cofferdam location. This terrace extends up to about E1evation 1485. Based on the extensive tal us upslope from this terrace, it is likely that this alluvium overlies and/or is interbedded with talus material. Downstream from the terrace, minor amounts of alluvial material are mixed in with talus which extends to river level. On the south bank, alluvium occurs downstream of the bedrock cliffs (Figure 5.16). Alluvium exposures on the north ~ank at the cofferdam loca- tion consist of a gravel to sandy gravel with subrounded to rounded coarser fragments, generally from 3 inches to 2 feet.. The matrix is composed primarily of sand with lesser a~ounts of silt. The composition of fragments is primarily granitic rock with lesser amounts of volcanic and metasedi- mentary rock~< Three borings (DH-1, 2 and 3) drilled by the COE in the river approximately 400 feet upstream of the cofferdam location (Figure 3.1), encountered rounded gra- vel~ cobbles, and boulders up to 3 feet in diameter .. These materials are uncemented in a sand matrix.. Rock fragments were fresh and hard, and consisted of granitic and metamor- phic rocks. Boring DH-3 encountered a 15 foot layer· of gravelly sand while localized traces of( clay were found on some fragments in borings DH-2 and DH-3 27). Alluvial thickness in the downstream cofferdam and portal location has been estimated from borings DH-1, 2 and 3, and seismic refraction lines SL82-4 (Appendix C) and DM-C (12} (Figure 3.1).. In the vicinity of the downstream cofferdam (Section DP-4, Figure 5.17) alluvial thickness reaches a maximum of about 90 feet in a bedrock trough on the snuth side of the r"iver. This area coincides with a sttear and fractur~ zone (GF 7J) descr ~ed in Section 5.2 (c). Allu- vial thickness decreases -cowards the north side of the river, genera 1ly from 40 to 60 feet beneath the river. On the north bank, the alluvium which probabl) is interlayered with talus, is about 20 to 30 feet thick. Downstream from the cofferdam location in the spillway area, no alluvium is exposed on the north bank due to abundant tal us and the presence of bedrock outcrops at the river edge, however, beneath the river channel, alluvial thickness is expected to be the same as in the cofferflam area. 5-28 I I I I I I I I I I & I I I I I I I I I I I I I I I I I I II • I I I I I I I I I (iii) Talus The extent of talus in the downstream cofferdam and portal area is shown on the geologic map and sections (Figures 5816 and 5.17). Talus occurs along the slopes of the north and south banks. o 1 us consists of angular to subangul ar fragments of diorite and quartz diorite. Fragments r~:1nge from sand-size •.1p to about 5 feet, with most blocks from 1 to 3 feet. Talus has been divided into two typ2s. Talus 1 is areas of active to semi-active.talus. These arebs have thin vegeta- tion with more than 50% of the talus exposed. Talus 2 is areas of inactive talus and more stable slopes where the vedetati on is thick and generally 1 ess than 50% of the talus is exposed (Figure 5.16). Talus 1 occurs on the north bank primarily in the area of extensive open joints and loose unstable rock as shown on Figure 5.16 and 5.18.· Three gullies within this area are actively funneling talus material. The causes of the active talus are the numerous she~rs in this area (Section 5.3 [c]). An area of active and semi-active talus occurs further upstream. between Elevation 1750 and 1575. The source of this talus is another area of open joints and loose, unstable rock resulting from intersecting shears and fracture zones. Minor amounts of Ta 1 us 1 occur on the south bank in gullies above the downstream cofferdam lc.~a t ion. Ta 1 us 2 occurs throughout most of the downstream cofferdam and portal area. ; Talus thickness has been defined based on the numerous seismic lines (SL82-3, SL82-4, SL82-6, SL82-7, and SL82-8) which were run in this area (Figure 3.1). Seismic veloci- ties up to 3,500 fps were considered to be talus in the damsite area (Tab1e 5e1). Based on this, talus thickness were found to range from 0 up to 35 feet. The thickest talus, generally 20 to 35 feet, was found along SL82-4 in the location of the tailrace and divErsion t~nnel number 2 outlet areas; along SL82-8 in the spillway flip-bucket area; and near the intersection of SL82-6 and SL82-3 above the two div8rsion tunnel routes. ( i v) Ground Water The j~tails of the ground wa"ter• conditions in the down- stream cofferdam and portal area are not well known. It is 1 ikely that ground water wi 11 be restricted to tre frac- tures and joints v1i thin the bedrock and in the all uvi urn beneath the river. Ground water \'las only observed at one location in this area. This was a small spring on the north bank upstream of the cofferdam location at about 5-29 Elevation 1525. Flow was less than 10 gpm. A general description of overall damsite ground water regime is presented in Section 5.6. (b) Bedrock Lithology The bedro-ck 1 ithology in the downstream cofferdam and portals 1 a- cation is primarily· ctiorite and quartz diorite which have been intruded by felsic dikes. Andesite porphyry alsv occurs in a small portion of this area. A detailed description of these rock types and the nature of the andesite porphyry/diorite contact is discussed in Section 5.1. The extent of these rock types is shown on i="i gure 5.16. Bedrock in this area is generally fresh to slightly weathered and very hard to hard. Hm1ever, the area has numerous shears, frac- ture zones, and a 1 terati on zones that 1 ower the bedr~ock qua 1 i ty. These structures are discussed in Section 5.3 (c). (c) Bedrock Structure (i) Introduction This section discusses the structural geology of the down- stream cofferdam and portals area of the Watana damsite and its relation to these proposed site facilities. This sec- tion is presented in two subsections: joints and signifi- cant geologic features. Significant geologic features include shears, fracture zones, and alteration zones as defined in Section 5.1 (c). (ii) Joints Joints in the downstream cofferdam and portals arP~ were found to belong to all four joint sets found at thE Watana damsite (Section 5.1 [c]). A plot of joints in the down- stream cofferdam and porta 1 area is shown on Figure 5.16. Table 5.4 lists the joint characteristics of this area. Joint Set I is the second most prominent set in the area. Joints trend northwestward ranging from 285° to 305° and averaging 290°. Dips are variable from 45° northeast to 60° southwest but are generally 85 o. southwest. Set I joints in ~his area are part of the Ib subset and are sub- parallel to parallel to the major shears, fracture zones, and alteration zones. Joint spacing varies from 1 inch in fracture zones to 3 feet and is generally 1 to 2 feet~ Joint surfaces are planar and smooth with carbonate coating locally. Set I joints often form the outcrop faces and are oft~n open. Open Set I joints are found at GF 6 and in the area of the proposed spillway cuts (Figure 5.2)o t ~"D(O 1 1 Aun~ u 1 5-30 I I I I I I I I - I I I I I I I I I I I I I I I I • I I I I I I I I I I I I I " Joint Set I I is weakly deve 1 oped in t.he downstream portal area, unlike the upstream portal area. This ~et strikes northwestward at 065° and is generally vertical10 Joint spacing is usually 1 to 2 feet where the set is present. Surfaces are planar to s1 i ghtly curved and smooth. No shears or alteration zones were found related to this set, however, mi·nor fracture zones are para 11 e 1 to it. Set r·I joints are the most common joints in this area .. Their range is highly variable~ but the major trend is northward at 005° with high angle dips_(80°) to the east. The joints are planar and smcoth with a 1 to 2 foot spac- ing. Minor carbonate and hydrothermal alteration are found 1 oca lly. Many of the Set I I I joints are open and form 1 arge areas of unstab 1 e rock where they occur with open Set I an0 Set IV joints as described above. Set I I I joints parallel shears, fracture zones, and alteration zones. Set IV joints are 1 m·J-angl e with strikes from 055° t0 110°, but average east at 090°. Dips are generally southward at 40°. These dips are towards the Susitna River, subparallel to parallel to the slopes of the gorge. This set is often discontinuous and where present, spaced at 2 to 3 feet. Surfaces are p 1 anar a·nd smooth. In summary~ Sets I and III are the most prominent joints and are parallel to the major· shears, fracture zones, and alteration zones. The occurrence of open joints of Sets I, III ar.d IV result in unstable rock masses in the area of the spillway cuts and above the downstream cofferdam. (iii) Significant Geologic Features The downstream cofferdam and portal area is located within two geologic features: Gc 6 and GF 7. These features are identified on the damsite geologic map (Figure 5.2) and the detailed map and sections of the downstream cofferdam and portals location (Figures 5.16 and 5.17). Geologic feature GF 7 was originally designated as the 11 Fir.gerbuster" by the COE in 1978; however, in order to conform to the system of designating significant geologic features begun in the 1980-81 Geotechnical Report (1) it has been designated GF 7. GF 7 and "Fi ngerbuster.. are used interchangeably. -Geologic Feature GF 6 Geologic featu~e GF 6 is located on the south banf. of the river in the vicinity of the downstream cofferdam. This feature is an area of extensive open joints and a 1 so includes m~nor-shears and fracture zones. The loose blocks assc~iated with this structure may affect the integrity of the south abutment of the downstream coffer- dam. This feature is describe:d in detail in Section 5,1(c). 5-31 -Geoloqic Features GF 7-11 Fingerbuster" Th,e "Fingerbuster" is primarily located downstream of the main dam centerline. The feature consists of shears, fracture zones and alteration zones which have been de- signated GF 7A through GF 7R. The re 1 at ion of these geologic features to the civil arrangements are shown on Figures 5.16 and 5 .. 17. Photographs of various features in the 11 Fi ngerbuster 11 area are shown on Figures 5~ 18, 5.19 and 5 .. 20. Based on the detailed mapping in 198'~, a more refined interpretation of the 11 Fingerbuster=' ltas been developed over that presented in the 1980-81 Geotechnical Report. Reconnaissance mapping by the COE in 1978 (27) and· Acres in 1980-81 (1) showed the presence of shear, fracture zones and alteration zones within this ar-ea. However, the extent of these features could not b~ determined. In :982 these geologic features were mapped in greater detail and their extent is shown or inferred on Figure 5.16. The 11 Fi ngerbuster" structures are best exposed on the north bank of the Susitna River from river level to El e.- vat ion 1725 downstream of the proposed diversion tunnels. Exposures show two strong trends of discontinuities: northwest-southeast and north-south. The northwest- sou~:heast trend is -parallel to Set I joints and is the major trend of the structure.. The north-south trend is parallel to the Set III joints. -Northwest Trending Structures The northwest ttending structures consist primarily of shears and associated alteration -zones. The strike of these structures is generally between 295° and 305° with variable: high anQle to vertical dips. Within the diorite these structures are<. frequently hydrothermally a 1 tered with gouge and breccia up to ~ feet thick. This altered and gouge material is yellowish orange, moderately to severely altered, soft and friable. The rock im~ediately surrounding these she:trs is generally fresh to s l i ght1y weathered and hard. Joint spacings range from very close to moderately close. Figure 5.19 is a photograph of shear and fracture .zone GF 7RO} Two 6 inch shears are surrounded by a fracture zone of very close to closely spaced joints, most of which are open. This zone is one of the sources of talus in the north-south gully which it crosses at about Elevation 1850c 5-32 ••• I I I ~ I I 'I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I The extent of these northwest trending shears ~.;ul d not be traced accurately beyond the area of the spillway. Within the area, most shears were traced across outcrops. Where not exposed, the shears tend to form topographic 1 ows. Weathering oi the soft shear material generally results in the fo\'r.·?~l,·;n of a bedrock scarp uphill from the shear and a ta 1 u:, pi 1 E: be 1 ow it (GF 7K on Section DP-1, Figure 5.17). Upstream from the spillway area, outcrops become fewer and ta 1 us more abundant. Shears are projected into this area based on their trend and lower seismic velocities (Figure 3.1). Seismic line SL82-8 indicates highly fractured bedrock (seismic velo- ;;ity of 7,000 fps) overlying moderately fractured bedrock (13,500 fps). Similar conditions are encountered to the east a 1 ong SL82-7 and SL82-6. However, on SL82-3 which crosscuts the trend of these structures, bedrock veloci- ties are 22,000 fps with no overlying intermediate layer. Similarly seismic line SL82-4, which subparallels the trend, also shows high velocities (18,200 fps) along 1ts 1 ength. Based O!l the work performed in this area to date, it has been assumed that most of these shears extend at 1 east· as far east as the propo:.ed area of di- version tunnel number 1. The anomalous high seismic velocities denoted in SL82-3 and SL82-4 are currently unexplained. wee suggest the higher velocities may be apparent velocities due to seismic waves refracted along ribs of more intact bedrock parallel to the north trend- ing shears (see Appendix C). Additional subsurface work in this area will be required. It is 1 ikely that the northwest-southeast shears extend to the sol!th bank (discussed below). Geologic feature GF 7J has been correlated from the north bank, beneath the river, to the south bank. This feature crosscuts both diorite and andesite porphyry, and projects beneath the proposed dam foundation on the south abutment. On the north bank in the andesite porphyry, GF 7J 1 ies in a deep, vegetated gully trending at 290° (Figure 5. 2). Exposures in the gully are very closely spaced, vertic.al fractures trending approximately 290° with thin zones of breccia and gouge. The andesite porphyry on the gully walls is slightly to moderately weathered/altered. Fig- ure 5.20 shows the sl i.ghtly altered shear/fracture GF 7J exposed at river level on the north bank. GF 7J has been projected across the river to correlate with features ex- posed along the base of the cliffs in area GF 6 (Figure 5.2). GF 7J is inferred to dip at 75° to the north to ver~ical, based on the slope of the cliff face and dips of shears behind and at the base of the cliff. 5-33 GF 7J has a 1 so been corre 1 a ted with a shear zone inter- sected from 97o8 to 104.0 feet in DH-1 {Figure 5.5). This zone is slightly to moderately altered, with 5hears 1 ess 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 1o-3 em/sec. Shearing may also exist in DH-3 vthere core loss of 6. 7 feet occurred near the top of rock between 94.0 and 104.7 feet. GF 7,J a 1 so projects to the southeast from the river bank where it is exposed in a steep-walled, 10-to 15-foot- wide gully at the andesite porphyry/diorite contact at Elevation 1750. The rock in the zonr itself has a granu- 1 ar nearly schistose character typical of catac1asti.c rocks. The rock has been healed and resheared. No exoo-, sures of GF 7J were found beyond this point, however, it has been tentatively correlated to a 10,000 fps zone on seismic line SW-1 (Figures 3.1 and 5.4). This correla- tion is questionable, since the zone was not intersected by BH-8, which lies between these features. Related to the northwest trending structures are areds of open joints and loose, unstable rock. The most sigtifi- cant of these areas occurs in the area of the proposed excavation for ·the spillway flip-bucket (Figure 5.16). This area extends frc,m river level to about Elevation 1850. Large blocks of detached rock are slumping along the !ntersection of Sets I, III and IV joints. Set IV is oriented subparallel to the Susitna Ri'ier and dipping towards the river· between 30° to 50° (Figure 5. 8). Set IV joints dips into the proposed spillway flip-bucket excavation, which may require additional rock support~ Above Elevation 1850, this area has a step-like·appear- ance caused by a series of west to northwest trending ridges and gullies fl"'t>m 10 to 20 feet wide. Spruce trees growing along these ridges show rotation, indicating recent movement. The "steps" lie along the trend of Set Ib joint and the northwest trending shears. These fea- tures appear to be a series of near-surface bedrock slumps. This zone may extend up to Elevation 2200 where it was correlated with a low seismic velocity zone on SW-2 .. -Nortr Trending Structures The larger, continuous north trending structures in the 11 Fingerbuster" are 1abe1led GF 7L, M, N, 0, P ·and Q (Figure 5.16). These structures are primarily fracture zones with associated minor shears, with the exception of GF 7Q, which is a major shear zone. These structures strike from 335° to 005° with dips generally vertical. 5-34 I I I I I I I I I I I· I I I I I I I I I I I I I I I I I I I I I I 'I I I I " The zones range up to 30 feet in width; however, most are 1 ess than 5 feet wide. Shears, where they occur in these zones, generally consist of up to 6 inches of breccia and gouge. An exception to this is GF 7Q which is discussed bel ow. The north trending shears 1 ikely extend beneath the Susitna River and correlate with similar strP"tures on the south bank in GF 6. GF 7Q is the most significant of the north trending fea~ tures. On the north bank, this structure is partially exposed in a 40-foot-wide gully filled with deep talus. The andesite porphyry/diorit·e contact is coincident with this structure to about Elevation 2000. A highly frac- tured c·utcrop of diorite breccia in an andesite matrix within this zone is moderately to severely weathered. Joints are very closely to closely spaced, trending 330° (Set I) and 0° (Set III), and dipping ste2ply to verti- cal. Slickensides on the gully walls indicate a vertical .. 0 displacementg Another outcrop at Elevation 1850 on the east side of the gully is very fine to medi urn grained diorite which has been intruded by thin veins of andesite containing di or·ite fragments. BH~2 was drilled across GF 7Q to determine its location at depth. A shear/fracture zone was intersected between borehole depths of 7L.2 and 177.1 feet, which was also coincident \\'ith the andesite porphyry I diorite contact at ---~""'••.; __ .__,,, 11)C: ~ .... ,.-4. fF1,..,,..,. .... J:: C\ Tllfle-· r-r(r ..!f.f" f''ri11:: appr·u7.JIIIat..t:I.Y .L£..v tct:t. \ 1yurt: :..J•VJ• · u ... " 1 .., .. , .... zone contains major shears and zones of alteration. RQDs and core recoveries W?re generally less than 50 percent and often 0 percent. A gully that branches from the main shear· to the northwest is inferred to be another shear and fracture zone (Figure 5. 2). The extension of GF 7Q to the south is based on a strong ~orth-south topogr~phic lineament which extends to Eleva- tion 1800 0n the south ~ank. No outcrops were found in this gully.. This feature, which is downstream from the rna in dam structure, has been considered s i gni fica nt in design. Every effort has been made to avoid placing major ci vi 1 structures in this area. Excavations for portals and tunne 1 s may encounter the north trending st~uctures; however, since these features are small and i r1tersect the ci vi 1 structures at a high angle, they should not significantly affect design. -Extent of 11 Fingerbuster 11 The main 11 Fingerbuster 11 trend is northwest-southeast. To the southeast the "Fi ngerbuster 11 shears have been tenta- tively correlated with shears in BH-6 and DH-21 (Figures 5*3 and 5.4). Few outcrops are found on the south bank al o'h·g the projection of the structure._ Shears are found 5-35 \'/here bedrock is exposed. Seismic lines SL81-20 and SLBl-21 indicate a bedrock low along the trend, however, bedrock seismic velocity is high (18)000 fps) indicating good quality rock. To the northwest, no bedrock outcrops are found between the north bank of the Susitna River and Tsusena Creek: however, an area of sheared and a 1 tered diorite similar in trend to the "Fingerbuster 11 wa~ found to the northwest of Tsusena Creek (Figure 4.1) and :.1ay be the continuation of the "Fi ngerbuster" structure. 5.4 -Spillway and Intake Areas (a) Introduction This section discusses the geology of the surficial deposits and redrock in the area of the main spillway and intake structures on the north -bank of the Susitna River. The general arrangement of these structures in relation to the surficial deposits and bedrock geology is shown on the damsite maps (Figures 5.1 and 5.2). Addi- tional detai1 of the spillway flip-bucket area is shown on the downstream portal area map and sections (Figures 5.16 and 5.17) and discussed in Sections 5.1 and 5.3. (b) Overburden and Ground Water Surficial deposits in this area have been investigated by geologic mapping, seismic refraction surveys, and boreholes. The material tyJ,Jes encountered consist of alluvium, talus and till (Figure 5.1).. Their extent and lithology are discussed indiv·idually below .. -Alluvium Alluvial deposits are located primarily in the river channel downstream from the spillway flip-bucket. In boreholes DH-1, DH-2, and DH-3 in the river (Figure 3.1) upstream from this area, the alluvium consists of a gravel to sandy gravel with subrounded to rounded fragments generally from 3 i nthes to 2 feet in diameter in a sand matrix with minor silt. Alluvial thickness is expected to be similar to that in the main damsite, generally less than 50 to 70 feet (see Section 5 .. 3). Additional thin alluvial materials are found locally above Elevation 2000. -Talus Talus occurs on the lower slopes of the gorge generally below E'\ ~vat ion 1950, and so wi 11 1 ike ly on l.Y be encountered in the ar~as of the lower spillway and srillway flip-bucket excava- tions. Talus consists of angular boulders of diorite and quartz diorite genera 11y from 1 to 2 feet in diameter. Thick ness is variable, rangiPg from 0 to 30 feet (Section DP-3, Figure 5.17). The seismic velocity of this talus material ranges from 1,200 to 3,000 fps (Appendix C) (see Section 5.3). 5-36 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I -Till Till, overlain by undifferentiated surficial deposits, occurs on the upper s 1 opes of the gorge generally above El eva·c ion 1950 (Figure 5.1). Minor amounts of alluvium and outwa5h deposits are found 1 oca lly. In the intake area these depos 1 ts thicken northwestward from about 10 feet at Elevation 2000 to about 50 feet at the power intake at Elevation 2225. Along the spillway, overburden 1s thickest, about 40 feet at the outlet facilities intake at Elevation 2150 but are thinner along the axis. At Elevation 2200 near the dam centerline, overburden thickness ranges from 0 to 10 feet. Between dam centerline and Elevation 1950, overburden thickness is :~enerally 20 feet along the spillway •. {c) Bedrock Lithology . {d) Bedrock in the spi llvYay and intake areas ranges from diorite to quartz diorite with minor amounts of granodiorite.· These rock types have been intruded by minor felsic and mafic dikes. Ande- site porphyry volcanic flows occur to the north and west of this area. The andesite porphyry/diorite contact crosses the Susitna River about 600 feet downstream of the spi 11way flip-bucket and about 200 feet west of the spillway at Elevation 2200. Detailed descriptions of bedrock lithology are presented in Section 5.1. Bedrock quality is variable throughout the ·spillway and intake area. In the intake area, seismic lines SL81-15 and SL82-10 (Figure 3 .. 1) show areas of poor quality bedrock with seismic velo- cities of 9,000 to 12,700 fps (Appendix C), primarily in ~he pro- posed intake channe 1. Bedrock quality appears better at the pro- posed power intake structure with velocities of 15,400 to 18,500 fps (SW-3 and SL82-5). Seismic 1 i ne SL82-5 extends along the axis of the spillway to about Elevation 2000 (Figure 3.1). The seismic line shows moder- ately good bedrock {seisrr!ic velocity 13,400 fps) to cbout Eleva·· tion 2150. Below this elev~tion to the end of the line at Eleva- tion 1990 is a zone up to 120 feet thick of poor quality bedrock (seismic velocity 7,500 to 9,000 fps). This zone extends to below the downstream limit of the proposed spillway excavation at about Elevation 1500 (Section OP-3, Figure 5.17). The low seismic velo- city bedrock is likely due to shears, fracture zones and altera- tion zones which are discussed below • Bedrock Structure (1) Significant Geologic Features The spi 11way and intake areas cross most of the geo1 ogi c features defined in the damsite area. These features are identified below but are discussed in detail in Section 5.1 and shown on Figure 5.2. 5-37 The intake channel is cross cut nearly along its axis by geologic feature GF 2, a zone of fractL:ing and minor shearing about 70 to 100 feet wide (Sec ,fl W-2, Ffgure 5 .. 4). The feature pas~~s through an area of the present power intake .channel intersecting it at a high angle. Minor shears re 1 a ted to the GF 3 feature may a 1 so be pre- sent in this area. The upper spillway lies in the GF 3 feature which consists of minor shears and fracture zones within moderately good bedrock. Discontinuities in this area trend primarily northwest and north-east.. Between Elevatioil 2200 and 2050, the proposed spillway crosses the GF 4 and GF 5 structures, which consist of northwest trending fracture zones with associated shears at1d alteration zones. The GF 4 fracture zones dip at high angles to the northeast while GF 5 is vertical. The decrease in bedrock qua-lity discussed above begins at these features. Below Elevation 1,850, the spillway passes through the "Fingerbusteru (GF 7) feature (se~ Section 5.3). 5.5 -Ancilliary Civil S~ructures Location (a) Introduction The additional geotechnical investigations, consisting of seismic refraction, soil borings and geologic mapping, which \'tere under- taken during 1982 serve to better define geotechni ca 1 cor,diti ons in the areas of some of the proposed anci 11 i ary fac i 1 it i es. The data presented in the following sections refines that information presented in the 1980-81 Geotechnical Report (1). (b) Emergency Spillway (c) A total of eight seismic lines and one borehole cross or inter- sect the alignment and approach channel of the proposed of the emergency spillway. Overburden depths in this area range between 15 and 60 feet, a decrease from the 15 to 100 feet originally estimated; The average over.burden depth in the in 1 et and fuse plu~ areas averages approximately 40 feet, decreased from the ini- tial estimate of 50 to 75 feet. The estimated bedrock surface is shown on Figure 6.7. Camp Ar~as Overburden thick ness in the areas of the proposed construction camp and permanent village sites (Figures 1.2 and 6.7) are expec- ted. to be. in excess of 100 feet, with the exception of the area north of the permanent village site near Tsusena Creek, wh~re bed- rock is estimated to drop off to greater than 200 feet below the surface. Foundation construction for the camp construction wi11 5-38 I I I I I I I I I I I I I I I I I I I I ~ I • I I I I 0 I I I I I I I •• I I I I I be in the gravels and sands of the glacial outwash and ice disin- tegration deposits which cover the areas (Units A thru C -Section 6). The permanent village, at current s:lte, is on shallow depo- sits of Units A through F over the lacustrine Unit B. While there is no boring information on ground water levels in these areas, it is expected that the water table will occur perched on top of the sporadic permafrost areas and on the top of the aquiclude lacustrine unit G (Section 6.3). Deeper aquifers may also exist at depth beneath Unit G. (d) Access Roads As described in the 1980-81" Geotechnical Report (1), access roads in the re 1 i ct channe 1 and borrow site areas wi 11 encounter the full range of glacial and alluvial materials. In general, selec- tive route alignment should allow avoidance of a majority of the boggy and fine-grained materials. Damsite access and construction roads wi 11 have to be routed to conform to the natural bedrock shelves which occur at various elevations in the damsite, and will be cut into talus and alluvial deposits down to bedrock. Signifi- cant rock excavation will be necessary where the roads cross'areas of steep topography, and in particular, where roads cross the 11 Fi ngerbuster" or enter the dams i te at the ~ Jwer elevations. Any roads bui 1 t on the south abutment above the break in the s 1 ope (Elevation 1900} and helow Elevation 2300, will encounter signifi- cant frozen and supersaturated glacial and alluvial overburden. 5.6 -Ground Water Regime The 1982 studies consisted of instrumentation readings of the pneumatic piezometers installed in the damsite during 1980-81. These readings continued to support those findin~s and conclusions set forth in the 1980-81 Geotechnical Report (l)o The geologic mapping revealed addi- tional springs on s'lopes at overburden/bedrock contacts (Figure 5.1). Instrumentation reading of BH-3 and BH-6 were made throughout the year on approximately monthly basis. BH-3 showed consistent reading of the ground water level within the upper 10 feet of the surface. The previ! ously reported 280 foot. reading, presented in Section 6 of the 1980-81 Geotechni ca 1 Report for this boring was erroneous. ~later l eve 1 s in BH-6 continued to show seasonal fluctuates between 103 feet to 150 feet be 1 ow ground surface with the 1 ower water 1 eve 1 being recorded in the 1 ate winter and spring and the higher water table in late summer and fall .. Runoff is noted along the toe of talus slopes on both abutments result- ing in icing of these areas during the winter. In addition, the per- ched ground water table on the . ~rmafrost on the south abutment results in numerous springs above Elevation 1900. BH-12, which experienced artesian conditions when. drilled, continued to flow at 2 - 3 gpm throughout t~e year. 5-39 Further investigations and instrumentation will be required in subse- quent phases of study to accurately define th~ ground water condition in the damsite area. 5.7 -Permafrost Regime The interpretation of the permafrost regime at the damsite remains unchanged as pr·esented in the 1980-81 Geotechnical Report (1). While only sporadic overburden permafrost has been detected on the upper north abutment, extensive permafrost exists on the south abutment. BH-6 continues to show near-zero permafrost at depths of ab.out 80 to 170 feet beneath the Susitna River (Figure 5.21), while DH-21, on the south abutment near river level, has thick ice in the casing year-round at depth of less than 20 feet. All the borings on the south abutment show permafrost, based on temperature measurements and very low rock permeabilities in fractured zones. The 1 ack of concentration of thermistor instrumentation on the south abutment precludes determination of annual frost conditions. On the upper north abutment however, the one borehole (BH-3) shows vertical annual frost penetration of about 8 feet3 with a mean low temperature below the zone of annual amplitude (about 70 feet deep) of 1.3°C. BH-6 appears to be located just about on the zero isotherm at the damsitc, with annual freezing and thawing to full depth of annual amplitude, about 80 feet. The borings on the upper south abutment all show permafrost from 0 to 25 feet with the active zone usua1ly around 10 to 15 feet thick. The depth of zero annual· amplitude ranges between 15 and 45 feet. The deeper ho 1 es, both in and out of permafrost, pick up a uniform indication of geothermal gradient at about 130 feet vertically below ground surface as de~cribed in the 1980-81 Geotechnical Report (1). The south abutm:nt is expected to be frozen to depths of between 100 to 250 feet and pc.;sibly greater. Some of the bedrock and alluvium adja- cent to the river is expected to be frozen (0 to -1c..C) to depths of 30 to 100 feet, but permafrost is not expected to ?.Xist in the alluvium under the river. The right abutment may have scattered permafrost below Elevation 1800 to 1900. 5-40 I I I I I I I I I I I I I I I I I I I -- - ---------- TABLE 5.1: WATANA DAMSITE AND VICINITY SEISMIC VELOCITY CORRELATIONS INFERRED MATERIAL Shallow, loose dry sands, gravels, topsoil Moist granular, well drained materials including loose ablation tills and outwash; slo~e wash, talus Moist terraces, gravels occur predominately as surface terraces of shallow fill material in relict channels, stream valleys. Hay include dt'ained till, frozen soil and lacustrine materials in damsite lacustrine materials (tills in damsite) -relative uniform -frozen Water Granular alluvium, saturated, outwash, saP~ and gravel stream and river deposits without high percentage of boulders or high density. May include some tills. Saturated dense alluvium, bouldery or frozen alluvium, most tills include dense talus and boulder, fields; very coarse, deeply buried alluvium. Higher velocity zones frozen if not very denseo Anomalous velocity zones. Outcrops and boringe in damsite show moderately fractured bedrock which would norma'ly be expected to have velocities above 10,000 fps. Material in ;og Lakes Relict Channel assumed to be frozen or well consolidated ti 11. Assumed to be bedroc~ for borrow sites to provide conservative estimates of material quantities. WATANA RELICT WATANA CHANNEL/ DAMSITE BORROW SITE D (1) 1000-1500 fps 1100-1600 1500-3500 1600-3350 3400-4600 3350-5200 5200 (upper left 4100-5200 750~-8000 abutment only) 5200-6000 4600-4800 4600-6100 {7000-8000 at river level and on south abutment only) (12000-14000 in riverbed near "The fins") 6000-9000 (rig,t abutment above El 1500 only) lt600-4800 5250-6600 6600-10800 -- J FOG LAKES RELICT CHANNEL 1100-2000 2000-30l'IO 3000-4600 4600-4800 4200-5000 4300-9000 8000-11500 (thick channel fills) -- WAf ANA -:1DRRO\'l SIr~~:$ C, E 2 F ... I 2 1000-"'-100 1500-.::flOO 2000-~i100 460G--Mi00 5000-"'~00 7500-~'-100 J 96so ... ·~oooo - - INFERRED MATERIAL Ice (on surface) Highly sheared, weathered or altered bedrock- very poor quality Sheared, fractured, weathered or alt.et'ed bedrock - mod~rately competent except poor quality on south abutment in 11000-12000 fps zones in Watana damsite. Bedrock, surface weathering or stress relief jointing to. moderate depths, generaly very competent. Bedrock, fresh, extremely competent, minimal fracturing or jointing. NOTES: (1) Seismic velocity in feet per second (fps) TABLE 5.1 (Cont'd) WATANA DAMSITE 11000 7000-10600 10600-13500 13500-16200 16200-22200 WATANA RELICT CHANNEL/ BORROW SITE D 11000 8000-12500 13000-14000 14000-16000 16000-23500 FOG LAKES RELICT CHANNEL 11000 8000-10500 10500-14000 14100-16000 16000-23000 ~II\ f ANA ,30RRO\~ SI~S C, E, ~., I, J 110CC 123Ut> ... 13300 160Cl"+"'" 17000 (2) Velocity ranges given match specific velocities in seismic refraction survey reports (Reference Numbers 12, 25, 39, 41~ 43), and are intended as a presentation of the interpretation of material types by AAI. Stated ranges are no\ intended to definitively predict material conditions or nature at a particulal' location or for a particular ~elocHy. --------------.. - ---- -------- ---- TABLE 5.2~ WATANA DAMSITE .JUlNJ Slit.. -sl .R1KE Dl~ SET QUADRANl RANGE AVERAGE** RANGE I**** All 265°-335° 300° 55°NE-65°5W NE 2B0° -345c 330° 55°NE-70°SW 310° SE 270°-350c 320° 60°NE-70°SW sw 270° -340c 325° 60°NE-70°SW 295° NW 265° -335c 325° 45°NE~60°SW 295° II All 015°-075° 055° 60°NW-60°SE NE 015°-065° 040° 60°NW-60°SE SE 025°-0BOc 050° 65°NW-60°5E sw 040° -OBOe 065° 70°N~ -70°SE NW 050° -070( 065° 60°NW-70°SE * Surface data only ** Major joint concentration *** Where set is present ****Includes Subsets Ia and lb (see Section 5.1) AVERAGE*~ 75°NE B0°NE B0°NE B0°NE 90° 75°NE B5°SW 75°NE B5°NW 80°NW B5°NW B5°NW 90° JOINT CHARACTERISTICS* SPACI ,NG*** SURFACE. CC !NDl TlONS RANGE AVERAGE TEXTURE COATING 1"-15' 2' Planar, smooth tc locally rough, continuous 2''-10' 2.' Same as cbove Carbonate and alteration, locally. Major carbonate at WJ-b 2"-10' 2' Same as above 1"-15' 2' Same as above Major ~arbonate at WJ-7 . 1"-15' 2' Same as above Minai' carbonate and alteration, locally. Major carbonate at WJ-4 1"-5' 1-2' ,, 1 11 -10 I -i 1-2' Planar to ·1inor carbonate irregular, smootr to slightly rougt 1"-10 1 4 1-2' Same as above Same as above 1"-10 1 -i 1-2 Planar, smooth t!: Same as wove rouqh 1 11 -10 1 -i 1-2 1 Same as above Same as above ---- REMARKS Parallel to major ~"tears, fracture zones, at"l..":' alteration zones .. ·~ ""'' - Pat·alle l to fract~ .. t·t:-zones in NE quadrant; n~ shears or alteration zon~ .. 0 - JOINT SITE STRI~E DIP SET QUADRANt KANtit AVtKAut."~'""' RANGE AVERAGJ:-!HI III All 335°-035° 350° 45°E-60°W 75°E NE 325°-025° 350° 55°E-60°W 60°E < SE --~ --------- sw 340°-020° 345° 60°E-80°VI 80°[ NW 335°-035° 005° 45°E-60°W 80°E IV All Variable Shalla\'/ to Moderate NE 075° 15°5 10°N st 090° 25°S 310° (I 40°NE sw 000° 05°E 090° 25°N NW 090° 10°N-10°S --- * Surface data only ** Major joint concentration *** Where set is present **** Includes Subsets Ia and Ib, {see Section 5.1) ------- TABLE 5. 2 (Cont'd) SPACING*** RANG!: AVERAGE 0.5"-5' 1-2' 2"-10' 1-2' ------ 0.5"-10' 1-2 1 0.5"-10 1-2' 211 -5'+ 1-2' 2"-5'+ 1-2' 6 11 -10' 2' 6"-10' 2.' 2"-5'+ 2-3' - SURFACE CONDITIONS REMARKS lEXlURI::. COATING Planar to slightl)' Parallel to mir,c,t shear-s, curved, smooth to fracture zonest Sl"ld sliqhtly rouqh . alteration zone~ .. Same as cbove MinoL' carbonate Weakl.y deve lope•: ~ and alteration, locally i . ------Not observed. Planar to Mino L' caL' bon at~ Sttongly deve lo~-."lt>j. irregulaL' smooth and alteration, to rough locally Same as above. Same as above Same as above .. Planar t.J Probably stress relief, irregular near surface. Same as cbove. ---Same as above .. Same as above. ---Same as above. Same as above. ---Same as above. Same as above. ---Same as above .. -------- -- --- ---.. ---- SH IKE JOINT SEl K_ANut AVERAGE*~ I 285°-345° 325° II 020°-060° 042° 0 III ------ IV Variable 045° * Surface data only ** Major joint concentration *** Where set is present TABLE 5.3: WATANA DAMSITE UPSTREAM COFFERDAM AND PORTAL AREA JOINT CHARACTERISTICS* DIP SPACING*** SURFACE CONDITIONS RANGE AVERAGEH RANI~F AVERAGE TE.XlURE. COATING 60°NE-60°S~ 90° 0.5"-5'4 1-2' Planar, smooth Alteration, to slightly rough locally. 65°NW-60°SE 85°NW 0.5"-4' 1-2' Planar to slightl\ --- curved, smooth to sliqhtly rough ------ ------------ 20°NW-30°SE 10°NW 0.511 -5 1 -+ 2' Planar to slightl} --- 10°SE curved, smooth ----- RH1ARKS _......... ·- Parallei to major shears~ fracture zones 1 and alteration zones. -- Parallel to minor fractuJ.-~" zones; many open; s lumpin~~ Not Observed. ~~ Discontinuous; probably stress relief. . .• ~:~=...., - TABLE 5.4: WATANA DAMSITE DOWNSTREAM COFFERDAM AND PORTAL AREA JOINT CHARACTERISTICS* JOINT SET --~==~Sil~·~Fl~KE~~~~~~=---~L~!~·Y~~~~~SP~,A~C~IN+b~*~**~Mrrl~~~~~UIRF~~~CE~~~Q·~~QIJ.MTI~p~~~~~S=-----~R(MARKS RANGE AVERAGE*~ RANGE AVERAGE*~ RANGE AVERAGE TEXTURE COATING I II III 325°-025° IV --~----------------;-------------~------------------------ 1"-3' 1-2' 1"-10'+ 1-2' 1"-10' 1-2' 4"-5 '+ 2-3' Planar, smooth Planar to slightb curved, smooth Planar, smooth Planar, smooth Carbonate and alteration, locally Mino!:' carbonat~ and alteration locally Subparallel to paratlel to a nears, fracture znr:if:'s and alteration zones. No shears or altera.t ::.t~n zones, but minor fra~ture zones. Weakly deve:t..:;ped. Parallel to shears. ftacture zones and alteration zones. ~~ny open. Olps toward river, [ parallel to slope. d1scontinuous. --------~--------~----------~----------L-------~~----~------~~--~-----------~------------~~~~~~~-~----,------- * Surface data only ** Major joint concentration *** Where set is present --.. ----- - .. -------- I I I I I I I I I I I I I I I I I I I ., '" "-'•.t:c:;.;,;rw~ REFERENCE: ' \ ~ ' '· ' \ iiLL AND OUTWASH TIL\.. ' \ \ lEGEND l a LITHOLOGY: ~ [~ • I OVERBURDEN· AREAS !t • •· .....J AND ALLUVIU. •• A OF TALUS. OOY\I/ASH 'flU.. "" . ..,, S SHOWN ' w ~ DIORITE TO QUARTZ · . L___;J GRANODIORITE DIORITE, INCUJOES MINOR r:.:.,·.-::1 ANDESITE PORPHYRY IN :. . •:,. AND LATlTE ' CLUOES. ilal~ DACITE r " · 1 DIORITE PORPHYRY CONTACTS: SURFICIAL DEPOSITS ~··· ..•..• BEDROCK/SURFICIAL O~"PO.SITS ~--~~-BEDRO<:K - CONTOUR LINES: -TOP OF BEDROCK coo-50' CONTOURS OAstiEOOUR: INTER.\ .. i:.. 100 FEET, ---TOP OF BEDROCK, CONTOUR INTEft\ilM.. ~"' .. • TOPOG '"' F~ET RAPHY, CCNTOUR INTERVAL&" _. OTHER: ~"•~' ? SPRINGS - l J ' \ ! ·i '\ , . ..... .... ""·"' . ' \ \ i I I I W-5 I t NOTES· I. OUTCROPS StiOWN ("N FIGURE 5.1. 2. LOCATION OF EXPLORATIONS SHOWN ON FIGURE3.1. l. GEOLOGIC SECTIONS ON FIGURES5.3 THROUGH5.7. <9. JOINT PLOTS ON FIGURE 5.8 5. ADDITIONAl GEOLOGIC DATA FROM COE, 1970, GEOLOGIC FIELD BOOKS I THRU 28 • G. TOPOGRAPHY FROM COE, 1978, l"= 2:00'. 7. El<fi'LORATION LOGS AND SEISMIC LINE SECTIONS IN APPENDIX. 0 AND AAI,I982. 0 EXTENT OF SHEARS, FRACTURE ZONES AND ALTERATIO~ ZONES ARE INFERRED BASED .ON GEOLoGIC MAPPING AND SUBSURFACE EXPlORATIONS, AND ARE SUBJECT TO Vt~IFICATION THROUGH FUTURE DETAILED SCAL~ 0 c LEGEND LITHOLOGY: D DIORITE TO QUARTZ DIORITE, t~UQ£S MINOR GRANODIORITE ~ ANDESITE PORPH.YRY,INCUJOES ~ MINOR DACITE AND t.ATETE k'S ,..., DIORITE PORPHYRY CONTACTS: __!~ BEDROCK, DASHED WHERE INf"ERRED. DIP WHERE KNOWN STRUCTURE: ~~ SHEA. R, WIDTH GREATER THAN 10 FEE'!; NEZ..~ ~ VERTICAL TO VERTICAL\.~ O!P ~ · EXTENT WHERE KNOWr.l A.'«WR·tN~ 7'0/ .-SHEAR, WIDTH LESS TRi\N 10 FEST., ~ INCLINEO,VERTICAL,,EXTENT 'WHERE K~ ., • ....-. AND/OR INFERRED E ·:J· FRACTURE ZONE,W!OilHl.R£A'TER TKA.'t -; .. • 10 FEET, NEAR·VERTtCAL 10 \I£RTlCAL. •• . UNLESS DIP SHOWN> Ele.nNT Vt"HmE ~ .. AND/uRINFERREO FRACTURE ZONE, WIDTH l.£SS THAP< 10 ' FEE!,INCUNEO.t.NEAR,V8mCAL 10 \'ERr~ EXTeNT WHERe KNOWN A.NOIOR 1«~ : JOINT; INCUNEO,OPEN lNCUHED,VERlr~ ,. (SETS IAND110NlY.E.~TRIRQf'5N~ · ALTERATION ZONE,AflPROXIS&ATE WiiJm SHOWN ..1.. ..L BEDROCK SLUMP OTHER• W•l t.t 200 400 FEET =iT? I I I I I I I I -I I I I I I I I I I I 2500 2000 1500 1000 SLB2·14 ~ I ,l,200FPS POWERHOUSE, TRANSFORMER GALLER'( ll SURGE CHAMBER PROJECTED 315'W F-!JF:l"" )' S,A TAILKACE/ BOTIOM TUNNEL PROJECTED IBO'W G d ACCESS TUNNELS 0 / .• I AZlMUTH 343o ~F SECTION-....lG~• LOOKING UPSTREAM DH-8 OH-8 PROJECTED po•w SL82·9 d; DH•6 PROJECTED DH-7 SlS2·2 !4,000 FPS /PROJECTED .2.SL82·4 I J :BOTTOM I PROJECTED j 185'W I o / ~~~m:m• ""f--AREAS OF' FRACTURE / ZONEs a MINOR SHEARS TREND ~05° WATANA DAMSITE GEOLOGIC SECTION W-1 SHEET I OF 2 22.,000 FPS 20'W -1> 13,CQ0-15,600 FPS % RQb 100 !10 0 EL 1 1 1 ~-1373 ~-1327 DH•4 , .. SUSITNA RIVER I l .. ...j I Dl:i-4 I r" PROJECTED 30'W j ' ·, ..... '-; .. :. :-. .' . . . ~-· ,,~: ~·.::i~:t I j ~t4~i-ER·I · I AR~A OF SHEARS, ) ·. FRACTURE ZONES AND. ALTE:R.ATION 1 ZONES. · TREND305• BOTIOM PROJECTED 330'E S,A l>SOO 2.000 1500 1000 LEGEND LITHOLOGY: E2l OV&RBURDEN, UNO!FFERENTJATED r--1 DIORITE TO QUAR'TZ DIOfl!TE, tNCWOES L__J MINOR GRANOOIORITE ~ ANDESITE PORPHYRY, INCLUDES MINOR L:.:::.:.....:J DACtTE a LATITE f.;..,\.'~ DIORITE PORPHYRY CONTACTS· ----~ OEOROCK/SURFIC!AL DEPOSITS --OEDROCK, DASHED WHERE IN FERREn STRUCTURE: r_ 'I !!HEAR, WIDTH SHOWN WHERE GRj:ATt:R L. ~-..J tHAN 10 FEET [. •·,·J.. fRACTURE ZONE, WIDTH SHOWN WHERE GREATER THAN 10 FEET CJ ALTERAi:QN ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS : ~SW·t :~TERSECTION WITH SEISMIC REI"RA..~N I LINE OM·C 1975, DAMES 8 MOORE SW· I 1978, SHANNON a WILSON SL 80·2 1980. WOODWARD-CLYDE CONSUL'I'A~'J'S SL 81·21 1981, WOODWARD-CLYDE CONSULTA.lliTS SL 82·1 1982, WOODWARD-~LYDE CONSULT.ANTS SEISMIC VELOCITY CHANGE ~~~go SEISMIC VELOCITY IN FEET PER SEC-oNO BOREHOLES: F:FRACTURE ZONE S:SHEAR A:ALT~~~ON g~~j9 COE ROTARY S DIAMOND CORE BOR:S"SS .BH·l AAI DIAMOND CORE BORING OTHER: W-5 l INTERSECTION WITH GEOLOGIC '1 SECTION W-5 • tGf2'> GEOLOGIC FEATURE DESCRIBED ttl. ~~ SECTION 5. NCtTES I. SECTION LOCATION SHOWN ON FIGURE 5.2. 2. VERTICAL a HORIZONTAL SCALE EQUAL 3. SURFAC!: PROFILE FROM 1" = 2.00' TOPOGRAPHY, COE, 1978. 4 EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDIX D AND AJ\1,1982 . ti. EXTENT OF SHEARS, FRACTURE ZONES,A.aJD ALTERATION ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SIJBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH FUTURE DETAILED INVESTIGATIONS. SCALE O~~~lO~Oiiiiiiiii~200 FEET FIGURE 5.3 .... I I I I I I I ! I I I j:: Ill Ill II- z I 0 ~ > Ut ...J Ill I I I I I I. 2500 2000 1500 1000 'I'.RQO 50 0 I I a. 1394 -12.77 OH-5 GustTNA.-~ , mvea j ...J D!i-5 ! ~PROJECTED J ~o35'W BOTTOM PROJECTED I55'W 343o...,.._..., AZIMUTH ---Joo-16-,r;o OF SECTION - LOOKING UPSTREAM •1. ROO 100 50 0 '----'----'1 EL ~-Z0!\5 "Eo RQO 100 50 0 .::... OH-21 'I PROJECTED '/ 45'W .,. I 7 f 1 1 7 W-2 "' ;;;,.; ~:..:.-.;J:. 1,2501 S,A-· • ~ FPS F4 S,F I 2o,ooo i I FPS ,: , ., S,A ·fi ! ;. j· I ((;F7) I 11 FINGERBUSTERn I AREA OF SHEARS, FRACTURE ZONES I. AND ALTERATION ZONES • ----+----..,.. ---PROJECTED FROM SOUTH BANK BOTTOM PROJECTED 685'E TREND 305" j TREND32.Q•.,.{ BOTTOM PROJECTED 195'W WATANA DAMSITE GEOLOGIC SECTION W-1 SHEET 2UF2 -1922 •c"'1 __ - I ~--, \ I t TREN!l ...--f' ' 290• 2500 2000 1500 1000 LEGEND LITHOLOGY: e.G.:] OVERBURDEN, UNDIFFERENTIATED CJ CJ] DIORITE TO QUARTZ DIORITE, INCWDES MINOR GRANOOIORITE ANDESITE PORPHYRY, INCLUDES MINOR DACITE a LATITE I(.,"'....., .. , DIORITE PORPHYRY CONTACTS: SEDROCKtSURFICIAL DEPOSITS BEDROCK, DASHED-WHERE INFERRED STRUCTURE: F: ~ SHEA_ R, WIDTH SHOWN WHERE GREATER L:: ,._j THAN lO FEET [-·] FRACTURE lONE, WIDTH SHOWN WHERE . GREATER THAN 10 FEET I )i-~1 ALTERATION. ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS : A S\Y·I INTERSECTION WITH SEISMIC REFRACTION I LINE DM-C 1975, DAMES a MOORE SW-1 1978, SHANNON a WILSON SL 80,2 1980, WOODWARD-CLYDE CONSULTANTS SL 81·21 1981, WOODWARC'-CLYDE C;JNSULTANTS SL 82-1 1982, WGODWARD-CLYOE CONSULTANTS SEISMiC VELOCITY CHANGE ~~go SEISMIC VELOCITY IN FEET PER SECOND BOREHOLES: BH·I F-FRACTURE -ZONE S=SHEAR A:.ALT~lff~ON g~:119 COE ROTARY a DIAMOND CORE BORINGS BH-1 AAI DIAMOND CORE BORING OTHER• W•5 I INTERSECTION WITH GEOLOGIC \V SECTION W-5 ~ GEOLOGIC FEATURE DESCRIBED IN ~ SECTIONS. NOTES I. SCCTION LOCATION SHOWN ON FIGURE 5.2. 2. VERTICAL a HORIZONTAL SCALE EQUAL. 3. SURFACE PROFILE FROM 1"=2.00' TOPOGRAPHY • COE, 1978. 4. EXPLORATION LOGS AND SEISMIC LINE SECTIONS SHOWN IN APPENDIX D AND AAI,1982. 5. EXTENT OF SHEA'tS, FRACTURE ZONES, AND ALTERATiON ZONE3 ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS, AND ARE SUBJECT TO VER;FICATION THROUGH FUTURE DETAILED INVESTIGATIONS. O~~~~IO~Oiliiiiiliiii2~01 0 FEET SCALE 22 : FIGURE 5.3 I I I I 2!500 I I I I. 2000 I t:i I ~ ~ z 0 1-~ w -' I w I 1500 I I I 1000 I I I I (ill) "THE FltlS~ AREA OF MAJOR SHEARS., FRACTURE ZONES AND ALTERATION ZONES 0 ..,30 ~ AZIMUTH ____..2. 03o c. OF SECTION LOOKING UPSTREAM ,~0' AREA OF MINOR SHEARS AND FRACTURE ZONES Q 0------..;.. ~VERSION TUNNELS WATANA DAMSITE GEOLOGIC SECTION W-2 SHEET I OF 2 2500 2000 TREND 305".~ 1500 1000 LEGEND LlTHOLOGY: f;:-· ·<1 OVERBURDEN, UNDlFFERENTIATm [----.. 1, DIORITE TO QUARTZ DIORITE, fflltLtc.~ ._,_J MINOR GRANODIORITE [....,.._::] ANDESITE PORPHYRY,I~~CLUDES M: S~R ,~·~,~~ DACITE a LATITE ~ DIORITE PORPHYRY CONTACTS: BEDROCK/SURFICIAL OEPOSITS ---BEDROCK, DASHED WHERE INFEE;;m STRUCTURE: f:'"J)• SHEAR,WIDTH SHOWN WHERE C~~TER L:..0.c:j THAN 10 FEET [-:-J· FRACTURE ZONE, WIDTH SHOWN~~ 4. GREATER THAN 10 FEET I A;:Cj ALTERATION ZONE, WIDTH ASS~"( GEOPHYSICAL SURVEYS: bsw-t INTERSECT<lN WITH SEISMIC RE'FR~"ml-< I LINE DM·C 1975, DAMES a MOORE SW·t 1978, SHANNON a WILSON SL 80·2 1980, WOODWARD-CLYDE CONSt:~":S SL SI·21 1981, lVOODWARD·CLYOE CQNSt.'t..~"'l'S SL 82.·1 1982, WOODWARD-CLYDE CONSC .... -::. .. TS SEISMIC VELOCI.TY CHANGE 12fp~0 SElSM!C VELOCITY IN FEET PE~ ~;:'0~JD BOREHOLES: BH-1 UTHOLOGY F., FRACTURE ZONE S•SHEAR A· ALTERATION. -ZO~.E OFH9 DH·I COE ROTARY 8 DIAMOND CORE E'ANSS BH·l AAI DIAMOND CORE BORING OTHER• W-5 ,~ INTERSECTION WITH GEOLOGiC ,. SECTION w-5 ltiF'2'> GEOLOGIC FEATURE OESCRIBEIJ ;)), ~ SECTION5. NOTES I SECl10N LOCATION SHOWN ON AGUR~ ::;,.:;: 2. VERTICAL a HORIZONTAL SCALE EC. _,:,.:. 3. SURfACE PROFILE FROM ln=2.00' TOPOGRAPHY, COE, 1976, 4.. EXPLORATION LOGS .d.ND SEISMIC UNE:: SE:;::T!ONS SHOWN IN APPENDIX 0 AND AAl, 1962 5. EXTENT OF SHEARS, FRACTURE ZONES,.:!.~:: ALTERATION ZONES ARE INFERRED BASE:' ON GEOlOGIC MAPPING AND SUBSURFACE EXFLORATIONS,ANO ARE SUBJECT TC VERIACATION THROUGH FUTURE DET~ED INVESTIGATIONS. FIGURE 5.4 I I I I I I I I I I I I I I I I I I ------------------------------------------------------~--------------~------------------~-------------------------~ 2500 2000 1500 1000 Q if_ DAM [ CREST EL.2210 % RQD 100 50 0 ' I I EL ...--1373 -.:iiiiiiij;l -1~7 DH·4 % flQD 100 50 0 ....____,__J [l -l:lll4 DH·5 -1217 SLS2.-ll ·~. '? I I _,.l;SOOFPS ' I -OH-4 DH-5 91VV'\FPS . . . : PROJECTED PROJECTED , ,...~ ,...._.~ ; 520'E 43~:":_ .J I ~F4A .. ; ?_{--....·:.:_.-.:_::_.·_:;-:·.··· · -· .. · -.··.· · ·•. ·•·... .· ... •··-'·~r.· ;/ ':..;.s~:-::·:-: } .. ~;1:-~~: ~ ;:· .. : ... ·.· ... ·.·-... _. ,.~ -~ •. ::·>1. - 1 ·~· / rJz~,:~'L.~i ~: I· 1 i1 1i I I 11 ki ~~) I I ,~. II r .. /~TREND :sos• ,-r· -AREA OF FRA.lTURE ·~·~' f! ZONES AND MINOR SHEARS /1 TREND 305° ~ .. AZIMUTH 023° .,._OF SECTION----..203° %RQD too 50 o OH·I2 LOOKING UPSTREAM EL. -i940 -1650 SL Sl-ZI PROJECTED 295'W v 7 /vi l~000-20,000 FPS I S,A- II!-,~: I "ANG::me" v ,.__. -AREA OF SHEARS, FRACTURE ZONES--~-··--•·· ------~~ AND ALTERATION ZONES S!>iiUM I PROJECTED • PROJECTEIJ FROM SOUTH BANK .225 • W , TREND 305'" ~-TRENO 305° I ~TREND320" F DH-24 PROJECTED 315'W WATANA DAMSITE GEOLOGIC SECTION W-2 SHEET 2 OF 2 '/oRQD 100 50 a ~-~ ~-1922 DH·24 ' i t, "f. TREND I 290'" f . \ !' H 81·21 Pn(IJECTED 160'E 1 2500 LEGEND LITHOLOGY; CVERBUROEN, UNOIFFa<amATED DIORITE TO QUARTZ OICRJTE, !NCWOES MINOR GRANODIORITE: ANDESITE PORPKYRY,!NCt.l.lD€5 to\I!I.Cfi DACITE 8 LATITE DIORITE PORPHYRY CONTACTS~ BEDROCK/ SURFICIAL n.E?OS!TS BEDROCK, DASHED Wf!E.~E tSF€!\RE.O STRUCTURE: SHEAR, WIDTH SHOW~ WHERE. \3REA~ THAN 10 FEET FRACTURE 'ZONE, W!l>'rH s.Htl'!\~ WHERE GREATER THAN 10 FEn ~ ALTERATION ZONE, WtZ,>TH AS SHuWN GEOPHYSICAL SURVEYS: bsw-I INTERSECTION WlTH SS.'SM:C REFAA/...~ I LINE OM-C 1975, DAMES a MOO~~ SW-t 1978, SHANNON a Wtl.S~~ SL 80-2 1980, V.'OODWARO-Ct.,\~ C<:\.-.-&:UA.'Il"'"S SL 8.1·21 1.981, WOODWARD·~~.,.~~ iC~ll.Til.'\-s, SL 82-1 1982, WOODWARO•C;,,•/;:)E CONSl.lUA.."'~ SEISMIC VELOCITY ;;'i~Ni>E: l~ggo SEISMIC VELOCITY t~ ~;;:Q f'ER St.-c~ BOREHOLES: BH·l LITHOLOGY S>~!:A.~ A• ~ '!1:RATIO:N · ::ur-E g~·l,9 COE ROTARY a DIA~,.._) ~OR!;: SOR! .. ~S BH-1 AAJ DIAMOND CORE ~.<;,.-tm-1:.; OTHER= W-5 l INTERSECTION WITH '>'r~t.Cu:<: \It SECTION W-5 tGFi) GEOLOGIC FEATURE ~~~RlSEt> iN ~; SECTION 5. NOTES L SECTION LOCATION ~>HOWN -.'\'< FiSC:RE ~.~ 2. VERTICAL a HORIZONTM. ~LE: EQUAL 3. SURFACE PROFILE FROM , .. .,~00' TQPOGRAPHY, COE, 197S. 4 EXPl~J,>l't..TfON LOGS AND SE::S\aiC tiNE SE~ SHOWN IN APPENDIX 0 AN~ ~A!, 1982 EXTENT OF SHEARS,FRAC~E :ZONES,AND AlTERATION ZONES ARE !~"~ED SASEO QN. GEOLOGIC MAPPING ANO ~!SS'JRSICE EXPLORATIONS,AND ARE: ~~ECT TO VERIFICATION THROUGH Ft:'tORE OEiAILEn INVESTIGATIONS. FIGURE 5.4 J I I I I I I I I I I I I I I I I I I E I1J .... 2500 2000 1500 l l / MAIN SI'ILLW.4Y - APUOACH CHA:li<EL a CONTROL STRUCTURE .~ -..::::2-r AREA OF MINOR ;;:~EARS AND FRACTURE ZONES OROUT GALLERY",, \, . - PENSTOCKS~' ACCt::SS TUNNE'L.\ ,·OM PROJECTED 445'E / 13,400FPS rSERV~CE d S?lll .. WA'f ~ ;tTREND 310° ' 8H·3 .PROJECTED /251 \\' 028""--AZIMUTH _.. 208o OF SECTION LOOKING UPSTREAM ... tltlt.' 100 50. 0 EL . -: -20t4 --~~ DH·IO ',)JH-10 6,020Fj:S '; .......... ',.~~'*"'~,__ __ j ·····' . :-:~~~~ !j /; . ,. .. !j '_)/!!fi,~~S,'t, d)j 0 ./fTRENO 305° /f€-TBY I : I I . ' I ' ll\LUS I : " . ~ lf:"O 2,000 FPS t I ~ 'f ... ~ SLB2·6 I' . .,...-·AREA. s OF. FRACTURE ZONES I 'x\: tp DM-C SUSITNA RIVER 1 ~ AND MINOR SHEARS I "' I I TREND 305• '-.. . SLS;'!•4 FR?JECTED I ');...:: .· 1:.' 110 E 1 I "-:-..,.: T t I I; ~~~go I ...... ~ i 6,100. ~ I · .. ~FPS l I I l 18,200-21,000 ..;<. ·~~ 1: (). i ., F.PS··· . '·ooo>~.,...~ ~ i ~PS '~,t:l I ~DIVERSION . \,G f 7 • I1J '!· I. }; l TUNNELS ~"FINGERBHSTER"---.,_~ • AREA OF SHEARS, ~~ ~• ~· t'RACTURE ZONES AND glt 4LTERATION ZONES ~ · ··TREND 305• TRFND 305• 40 'WATANA DAMSITE GEOLOGIC SECTION W -3 SHEET I OF 2 J ~ 2.500 2000 1500 1000 LEGEND LITHOLOGY: OVERBURDEN, UNOIFFEHe:NTlAT£0 DIORITE TO QUARTZ OIORITE, !NCWDES MINOR GRANOOlORr. ~ ANDESITE PORPHYRY,lNCLUD!lS MhiOR DACITE a LATITe: t~;'2J DIORITE PORPHYRY CO~HACTS: SEDROCIU SURFICIAL DEPOSITS --SEDROCK,OASHED WHERE INFERRED STRUCTURE: SHEAR, WIDTH StiCWN WHERE GREATER THAN !0 FEET FRACTURE ZONE, WIDTH SHOWN WHERE GREATER THAN 10 FEET ALTERATION ZONE, WIDTH AS SHCWN GEOPHYSICAL SURVEYS : o SW-1 INTe:RSECTION WITH SEISMIC R~Ff?.CHON I LINE DM·C 1975, O.O.MES a MOORE .SW· i 1978, SHANNON & WILSON SL 60·2 1380, WOOihVARO·CL'fDE :::cr-<S:'-1AN!S SL 8!·21 1981, WOODWARD-CLYDE CO~JL~~"t'rS SL 82-1 1982, WOODilARD·CLYDE CONSt:L~NTS SEISMIC \'EbiCITY CHANGE ~~go SEISMIC VELOCITY 11.1 FEET PER SECOM:l eOREHOLES: F-FRI\CTURE -ZONE LITHOLOGY S=SHEAR A= ALT~~1J~UN 8~:119 COE ROTARY a DIAMlJND CORE SORiNGS BH-1 AAI DIAMOND CORE BORING OTHER: W-5 l INT£RSZCTION WITH GEOLOGtC 'i' SECTION W-5 .~ GEOLOGIC FEATURE OESCRIBED!N ~ SECTIONS. NOTES l. SECTION LOCATION SHOWN ON FIGURE 5.2. 2. VERTICAL a HORIZONTAL SCALE EO'll'AL.. 3. SURFACE PROFILE FROM 1"=200' TOPOGRAPHY, COE, 1978. 4 EXPLORATION LOGS AND SEISMIC LIME SE':TIONS SHOWN IN APPENDIX D AND f.AI,I982. 5. EXTE1·lT OF SHEARS, FRACTURE ZONES,ANO ALTERATION ZONES ARE INFERRED eASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATIONS,AND ARE SUBJECT TO VERIFICATION THROUGH fUTURE DETAILED INVESTIGATIONS. 0 IOQ 200 FEET SCALE L-.~----=a FIGURE 5.5 I I I I I I I I I I I I I I I I I 2500 2000 ~ w w "- % 0 j::: ~ .., .... w 1500 1000 ti ~· "1. ROO 100 ~0 0 EL ---..... -1381 --....::=::= ., AZIMUTH~ "'OS" 028 ~F SECTION ~ LOOKIN"i UPSTREAM "/. RQO JOO SO 0 t I l EL -1408 SUSITNA RIVER . 1 (GFS) ..,. · ·AREA Oj;EXTENSIVE • 01-!EN JOINTS ;- SHEAR.' 3.0' GOUGE TREND 325" I I I WATANA DAMi':lT~ GEOLOGIC SECTION V'J-3 SHEET 2 OF 2 2500 2000 l500 ~ J 1000 LEGEND LITHOLOGY: t· ;'~·.'I OVERBURDEN, UNDIFFERENTIATED II OIORITE TO OUARTZ DIORITE, tNCUlDES L__l MINOR GRANODIORITE ~ ANDESITE PORPHYRY, INCLUDES MINOR ~ DACITE a LATITE F<'"\""V ""\ I DIORITE PORPHYRY CONTACTS: BEDROCK/SURFICIAL DEPOSITS ---, BEDROCK, DASHED WHERE INFERRED STRUCTURE: SHEAR, WIDTH SHOWN WHERE GREATER THAN 10 FEET FRACTURE ZONE, WIDTH SHOWN WHERE · GREATER THAN JO FEET ALTERATION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS: 8 SW-1 INTERSECTION WITH SEISMIC R~llON I lfi'!E DM-C 1975, D.~MES S MOORE SW-I 1978, SHANNON 8c WILSON SL 80·2 1980, ·,'VOODWARD-CLYl''i CONSt.~"ii\NTS SL 81·21 1981 I WOODWARD-CLYDE COOSU.i7>NTS SL 82-1 1982, WOODWARD-CLYDE CONS::U'Ato1'~ SEISMIC VELOCITY CHANGE 12F~~O SEISMIC VELOCITY IN FEET Pffi ~CONI) BOREHOLES: LITHOLOGY F,.FRACTURE ZONE S•SHEAR A• ALT~~'N~C'i'ii DR·I9 DH·I cOE ROTARY a DIAMOND CORE ~bRINGS nH-1 AAI DIAMOND cORE BORING OTHER= W-5 I INTERSECTION WITH GEOLOGlC \V SEcTION W-5 !;OTES GEOLOGIC FEATURE: DESCRIBE~t"N SECTION 5. !. SECTION LOCATION SHOWN ON FlGtJR~ ~.2. 2. VERTicA._ a HORIZONTAL ScALE E;q~. 3. SURFACE PROFILE FROM 1"=200' TOPOGRAPHY, coE,I97B, 4 EXPLORATION LOGS AND SEISMIC ll~ SECTIONS SHOWN IN APPENDIX 0 AND AA I, 1~.<:<~ • !: EXTENT OF SHEARS, FRACTURE ZONE;~.~ND ALTERATION ZONES ARE INFERRED SA$~0 ON GEOLO.GIC MAPPING AND SUBSURFACE: cXPLORATIONS,AND ARE SUBJEcT T.;;; l!ERIFICATION THROUGH FUTURE DE.~IlEO INVESTIGATIONS, O~~--li50~0Uiiiiiiiiii2~ft0 FEET SCALE f-_ _\jill ~ F!GURE 5.5 ~-------------------·----------------------------------~------------------~--------~----------------------------------------------~ I I .. I I I I .I I I ~000 I I I I I 1000 I I I 0 E) •THE FtNS" osso~ AZIMUTH __.266 o OF SECTION LOOKING SOUTH ~---------------· AREA OF MAJOR Stt. ARS, FRACTURE 2'~4F.S AND :.LTERATION ZONES ' \ 'J. ·TREND 3ZO" -PROJEC "ED 60'NE TREND050• l ~TREND ;}J5" SLB2-IO ~ l WATANA DAMSITE GEOLOGIC SECTION W--4 SHEET I OF 3 SLB0-3 ~ 1,650 i FPS'· i 22,200 FPS I I ' I :t: U· !;t :2:1 j 2000 1500 1000 LEGEND LITHOLOGY: f: . . • ;; J 0\IERBUROEN, UNDIFFERENTIATEO r--1· DIORITE TO QUARTZ DIORITE, INCU!!>ES L. . ....J MINOR GRANODIORITE r-::;.] AN!>ESITE PORPHYRY, INCl-UDES MiNOR ~ DACITE a l.ATITE • [~ .... ~ j DIORITE PORPHYRY CONTACTS: -----BEDROCK/SURFICIAL DEPOSITS ---BEDROCK, DASHED WHERE INFERRED STRUCTURE: f:'""-:f.l:f) SHEAR, WIDTH SHOWN WHERE' GREATER b _ _::j THAN tO FEET C.··.J· FRACTURE ZONE, WIDTH SHOWN WHERE GREATER Tt!AN JO FEET [3:a ALTERATION ZONE, WIDTH AS SH\''n'N GEOPHYSICAL SURVEYS : bsw-I I!JTERSECTION WITH SEISMIC Ri:.f'Ri\CTJCN I LINE OM-C 1975, DAMES a MOORE SW-I 1978, SHAN:-10~1 a WILSON SL 80-2 1980, WOODWARD-CLYDE CON$Ut.TA.~iS SL 91·21 1961, WOO~WARD-CLYDE CO!<~St.!l.'i.\."<TS SL 82·1 198~, WOODWARD-CLYDE CONS~t.-mNTS SCALE SEISMIC VELOCITY CHANGE '?fp~O SEISMIC VELOCIIY IN FEET P~R: ~\JNO BOREHOLES: BH·J F-FRACTURt;; -ZONE S•SHEAR t::rA• ALT1'6~FJC'N g~:119 COE ROTARY a DIAMOND CORE ;,OR:NGS BH-.1 AAI DIAMOND CORE BORING OTHER' W·5 1 INTERSECTION WITH GEOL04:C' \lf SECTtON W-5 ~ GEOLOGIC FEATURE DESCRl~5.\;:'tl'( 1.,.~' SECTION 5. NOTES I. SECTION LOCATION SHOWN ON FIGl!RE: !\.!2. 2. VERTICAL a HORIZONTAL SCALF.: F;.~..,AL. 3. SL'RFACE PROFILE FROM I"= 200' TOPOGRAPHY, COE, 1978. 4 EXPLORATION LOGS AND SEISMIC LL~~ S:O:CTIONS SHOWN IN APPENDIX 0 AND A AI, 19S;:; 5. EXTENT OF SHEARS, FRACTURE ZO.N.t;$.AIIlt> ALTERATION ZONES ARE INFERREll aASEO ON GEOLOGIC MAPPING AND SUBSURFA~ EXPLORATIONS,AND ARE SUBJEcT "tiC VERIFICATION THROUGH FUTURE t'~T><ri..EO INVESTIGATIONS. 0 100 200 FEET r.: •• =· FiGURE 5.H I· I I I I I I I I I I I I I I I I l 1-..., ..., u. 2000 z 1500 0 ~ > ..., ..J w 1000 I I l ! (,)t !;t ::1!: ~v1-2c F.ro.JECTED W-2 35'S 086 o..--0~ZJ~&mN----..266 o LOOKING SOUTH RIVER FLOW~ <t, DAM CREST EL 2210 '1~"' SW·2B ·< PROJECTED 65'S t OH-IO %-ROO 100 50 0 El. =::;:;;;;;;;"";-2014 ~-!83() DH·IO .1250 FPS / SLS2·1 4> I SW·?. PROJECTED lOO'S j ~ /12,500 FPS ....• -:..;.:.::.f,;.:..:...:;..o::.c.::,:.:.j:£:.::::::::::.=::t:L::;;s::.::.~::..:.~·_...;..:.. ... ·~-... ---c..t-..... ,.;......,._.;...:_._ _ --:..:,;.~·~~~·~:_.r~,=-~.:_-..-:-. i :;.·:....· ::.'.:.!y-;.....--- s,A I ! 6300 F?s ~ AREA OF MINOR SHEARS AND FRACTURE ZONES 13,500 FPS .!l I F 13,000 FPS /--" .// h !I ,1 j/ II BOTTOM // ,ir r,:mecreo 1. ..T'""""' ! j J: 1/ 16,200-18,000 FPS ~r,OOO FPS 0 i /;/j-·· ~~D ~~l{L/ r ARE~~:~ACTURE l ;• ~I : ....---.... d··.-~.No ZONES AND 'MINOR , ·TUACCNENSELS ,. '"' ·• •' JV.I SHEARS TREND 310° ·~ 1-DIVE'P.SION t~· G!:.!A} A • .. · TUNNELS //._~ POWER:IOUSE,TRANSFORMER GALLERY AND LJ r------------------JE..If :....._ ________ -;•'-j·f-1____ f:.l I SURGE CHAMBER PROJECTED 930'5 _j .~==================~========~.#!/~. ====~-=====~7~:.~------------~~--~--~-------: 1' ·-~·--+-Ji7·--------,/'-i-·~2_·~--+L------------+t----:----===d I--INTERSECTION WITH . I NORTH DIVERSION TUNNEL 3 WATANA DAMSiTE GEOLOGIC SECTION W-4 2000 ISOO 1000 ...J LEGEND LITHOLOGY: OVERBURDEN, UNO,FFERENTIATED DiORITE TO QUARTZ DIORITE, INCLUDES MINOR GRANOOIORITE ANDESITE PORPHYRY, INCLUDES MINOR DACI.TE a LATITE DIORITE PORPHYRY CONTACTS: BEDROCK/ SURFICIAL DEPOSITS -=--BEDROCK, DASHED WHERE INFERRED STRUCTURE: SHE:AR, WIDTH SHOWN WHERE GREATER THAN 10 FEET FRACTURE ZONE, WIDiH SHOWN WHERE GREATER THAN 10 FEET ALtERATION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS : bsw-1 INTERSECTIO~l WITH SEISMIC REfRACTION I LINE DM-C 1975, DAMES a MOORE SW-I 1978, SHANNON a WILSON SL 80·.2 1980, WOODWARD-CLYDE CU.. ... SO!..TANTS SL 81·21 1981, WOODWARD-CLYDE CONSUl..l"ANTS SL 82-l 1982, WOODWARD•CLYDE CUNSUlfANTS SEISMIC VELOCITY CHANGE ~~~~0 SEISMIC VELOCITY IN FEET f't:R SECONO BOREHOLES: DR· IS. OH·I BH-1 OTHER: W·5 .Jt F= FRACTt.'Rt: ZONE S=SHEAR 1>.• ALTERATION ZONE: COE ROTARY a DIAMOND CORE 130RINGl' AAI DIAMOND CORE SORIN'l INTERSECTION WITH 5EOt,Q";~ SECTION W-5 (G'f2\ GEOLOGIC FEATURE D£S::RlS~tiiN ~ SECTION5. NOTES 1. SECTION LOCATION SHOWN ON F!GVRt: 5.2 . 2. VERTICAL a HORIZO'-!TAL SCALE ~~I.JAL. 3. SURFACE PROFILE FROM !", ?.00' TOPOGRAPHY, COE, l978. 4 EXPLORATION LOGS AND SEISMIC L(!l;t SECTIONii SHOWN IN APPENDIX D AND AA1.19S~. 5. EXTENT OF SHEARS, FRACTURE :ZQN£S,AND ALTERATION ZONES ARE INFE."lAE~ ~A$ED ON GEOLOGIC MAPPING AND SUBSUR~ EXPLCRATIONS,AHD ARE SUBJECT l\l VERIFICATION THROUGH FUTURE O.tiAILED INVESTIEATION3. 0 100 SCALE /"!""""' ?\ 200 f'E"ET i? FIGURE 5.6 L SHEET 2 OF ·~ . --------~-·-----------·- I lj tl I I I I I I I I I I I I I I I 1-w w IL.. 2000 1500 z 0 ~ w ...J w SW·2 PR~?JECTEO IOOSi- ' r ' I I I I I *r il I ~j l }TREND 0"~ I BOTTOM PROJECTED 230'S ! SL 60·2 13,000·16,200 FPS .1,250 FPS ~ -TREND 305' SERVICE SPILLWAY\:j TAILRACE TUNNELS I PROJECTED 495' N ~ ·TREND 00 PROJf.:CTEi) teo'N 086'" ....._.__AZIMUTH ---~~oo-zsso OF SECTION LOOKING SOUTH RIVER FLOW_.. AREA OF SHEARS, FRACTURE ZONES AND ALTERATION ZONES . .,;.. TRE~lD 29:5 • WATANA DAMStTE GEOLOGIC SECTION W~ 4 SHEET 3 OF 3 ~ ·--~--------------------·--------~----·----------------------~ 2000 1500 1000 l .....! LEGENC UlHOLOG't. ; · . : J OVERBURDEN, UNDIFFERENTIATED r--1 DIORITE. TO. OUARTZ DlORlT£, lNCLUDES l____j MINOR GRANODIORITE r::::::::J ANDESITE PooPHYRY,INCLUDES I.!IHOR L:::.:.:..::] DACITE a LAT1TE ~~-"~~ DIORITE PORPHYRY CONTACTS; -----BEDROCK/SURFICIAL DEPOSITS ---BEDROCK,DASHEO WHERE INFERRED STRUCTURE: SHEAR. WIDTH SHOWN WHERE GREATER THAN '0 FEET FRACTURE ZONE, WIDTH SHOWN. WHERE GREATER THAN 10 FEET ALTERA110N ZONE, WIDTH AS SHO'ft"N GEOPHYSICAL SURVEYS : 6 SW·l INTERSECTION WITH SEISMIC REFRACTlON I LINE DM·C 1975, DAMES B MOORE SW-1 1978, SHANNON a WILSON SL 80·2 1980, WOODWARD-CLYDE CONSUlTANT$ SL 91·21 1981, WOODWARD-CLYDE CONSUt;r~I'>ITS SL 82.·1 1982, WOODWARD-CLYDE CONSlll't\NTS SEISMIC VELOCITY CHANGE; ~~~go SEISMIC VELOCITY IN nET PER SE':ONI) BOREHOLES: BH·I F. FRACTURE -ZONE S=SHEAR A• ALT~AJJO~ g~:\9 COE ROTARY a DIAMOND CORE ~~IN.GS 8H•I AAI DIAMOND CORE BORING OTHER• W·5 ! INTERSECTION WITH GEOLOGt': \V SECTION W-5 ~· ~ GEOLOGIC FEATURE DESCRIBI::L'IN ~ SECTIONS. NOTES I. SECTION LOCATION SHOWN ON FLGURE ~ ~ . 2. VERTICAL a HORIZONTAL .SCALE fQ:u.\L 3. SURfACE PROFILE FROM l" = 200' TGPOGRAPHY, COE,l978. 4 EXPLORATION LOGS AND SEISMIC UNS $5.C\'lONS SHOWN IN APPENDIX D AND AAI,I9S:.; 5. EXTErn.OF SHEARS, FRACTURE :ZONE$.~~0 ALTERATION ZONES ARE INFERRED .13.\SEQ ON GEOLOGIC MAPPING ANO SUBSURFACE EXPI..OPATIONS,AND ARE SUBJECT TQ VERIFll.ATION THROUGH FUTURE DETA!LEO iNVESTIGATIONS. 0 101).. 200 FEET SCALE ,....... ....... l FIGURE 5.6 I I I I I I I I I I I I I I I I I I I LEGEND LITHOLOGY; OVERBURDEN, UNDIFFERENTIATED DiORITE TO QUARTZ DiORITE, INCLUDES MINOR GRANODIORITE ANDESITE PORPHYRY, INCLUDES MINOR DACITE a LATJTI:: I ('\c; ;"' I DIORITE pORPHYRY CONTACTS: BEDROCK/ SURFICIAL DEPOSITS ---BEDROCK, DASHED WHERE INFERRED STRUCTURE: SHEAR, WIDTH SHO~I~ WHERE GREATER THAN 10 FEET FRACTURE ZONE,WIDTH SHOWN WHERE GREATER THAN 10 FEET p;f~~! ALTERI\TION ZONE, WIDTH AS SHOWN GEOPHYSICAL SURVEYS : ~SW·I INTERSECTION WITH SEISMIC REFRACllON l LINE DM-C 1975, DAMES a MOORE sw-I 1978, SHANNON a WILSON SL 80·2 1980, WOODWARD-CLYDE CONSULTANTS SL 81·21 1981, WOODWARD· CLYDE CONSULTANTS SL 82·1 1982, WOODWARD-CLYDE CONSU!JANTS SEISMIC VELOCITY CHANGE ~~~go SEISMIC VELOCITY IN FEET PE~ SE~Or-Q 2500 2000 1500 BOREHOLES: BH-1 LITtiOLOG'Y ,FRACTURE ZONE S•SHEAR A• ALTERATION ZONE DR·I9 DH·I.· COE ROTARY S DIAMOND CORE BORINGS 81-l-1 AAI DIAMOND CORE BORING OTHER: W·5 I INTERSECTION WITH GEOLOGIC 'Y SECTION w-5 ~ GEOLOGIC FEATURE DESCRIBED IN ~ SECTION5. NOTES I. SECIIoN LOCATION SHOWN ON FIGURE 5,Z. 2.. VERTICAL a HORIZONTAL SCALE EQUAL. 3. SURFACE PROFILE FROM I"" 2.00' TOPOGRAPHY, COE,I97B. 4. EXPLORATION L.OGS AND SEISMIC LINE SECTIONS SHOWN IN APPE'IlOIX D AND AAI, 1962. 5. EXTENT OF SHEARS, FRACTURE ZONES, AND ALttRATION ZO'lES ARE INFl::RREO BASED ON GEOI..QGIC MAPPING AND SUBSURFACE EXPLORATIONS, II.ND ARE SUBJECT TO VERIFICATION T!iROUGH FUTURE OETAIL.EO INVESTIGATIONS. 09...,0 AZIMUTH 272 o t'C. ~FSECTIO~ LOOKING SOUTH RIVER FLOW_.... SL81-20 PR9JECTED W·l - 132055 1 -1650 t OH·23 PROJECTED 35's OtHl'. SLSI-21 SLSI-20AND SW·tA ' 14,000-20,0CO FPS (§) "FlNGERBUSTER" ·----AREA OF SHEARS, FRACTURE ZONES---··-. AND ALTERATION ZONES ~ PROJECTED FROM SOUTH BANK TREND 320° TREND 3(15' BOTIOM PROJECTED 85'S WATANA DAMSITE GEOLOGIC SECTION W-5 "~'• llO.D tOO GO 0 EL L,,,.c.L......l '"'" --1:. .... ,;:;; OIH!B -1840 SW·I /?.. o~~~5~o~oii;;;iiB:'l;j·Ro FEET SCALE ;:::_,__ • - sw-r PRQ.;~ 2Q'N -~ 2000 FIGURE 5.7 ~--------------------------------------------------------~------------------------------------~--------------------------------------~------------------~----------------~ I I I I I I I I I I I I I I I I I I .I E 0 s N COMPOSITE JOINT PLOT SOUTHEAST QUADRANT N=7"?.1 N COMPOSITE JOINT PLOT NORTHEAST QUAuRANT N= 857 w w E E ~ COMPOSITE JOINT PLOT SOUTHWEST QUAORANT N~329 ~----· w SET \ m SET:ISl: ~--~~ N COMPOSiTE JOINT PLOT NORTHWEST QUADRANT N., 781 WATANA DAMSITE COMPOSITE JOINT PLOTS • "-~---\ / ,./.·' f .~ :;, J ...... \ / '/ , _ _,;- SCALE Q NOTES s N POINT STRlKE ~ A oso• so•sE B 330" go• c 045" lO"t•\'11 0 2A:;~ 50"NE E 0' so•w NOTE, PLoWING BY PROJECT:;:,.. {11: PfPJC 3~01CULARS TO .iC't.l~T PLANES ON SURFACE OF LOWER "'t~'MISPHERE POINTS ARE PLOTTED Q/'li ~N EQUAL- AREA NET. JOINT PLOTTING ME"fllil.)O L CONTOURS ARE PERCENT OF .JOINTS PER: 'o,"'l. OF' AREA. CONTOURS SHOWN -I ,3, a 5%, 2. N EQUALS NUMBER OF DATA POINTS. 3, COMPOSITE PLOTS INCORPORATE ALL .!Q;~'t OATA FROM· THEIR RESPECTIVE QUADRANTS. 4. JOINT PLOTS FOR JOINT STATIONS (WJ• . !:,~, 4,5, s;r. S S.~ I~ AAI, 1982. FIGURE 5.8 I I • GFIP I I I I I I I I • I I VlEW LOOkiNG NORTH ALONG STRIKE OF SHEAR; DiP 57° WEST RIVER LEVEL-NORTH BANK "THE FINS" AREA I I NOTE: L GEOLOGIC FE"-TURE DES~RIBED IN SECTION 5. I I I WATANA OAMSITE I TYPICAL SHEAR laPorol I FlGUR€. 5.9 ~~ I I I I I •• I I I I I I I I I I I I I I CAR90N,,.TE VEIN UNALTERED DIORITE NORTH SIDE OF GF 1~ SHEAR(. ALTERATION ZONE RIV~R LEVEL-NORTH BANK ' THE FINS" AREA WATANA DAMSITE SHEAR I ALTERATION ZONE I L ___________ FIG_URE_5.10_~-~~ill----il~ II THE FINS 11 AREA I It I I I w>- I t-0: ->-(/.):X: Ll.la_ Oa: zo etc.. I I I I I I I I I I I I I I w t- 0: 0 0 L 1 .. ANDESITE PORPHYRY -, -;; NOTES: LOOKiNG DOWNSTREAM (WEST) FROM CENTERLINE I. GEOLOGIC FEATURES DESCRIBED IN SECTION 5. 2. DASHED LINE IS ANDESITE PORPHYRY/ DIORITE CONTACT. WATANA DAMSITE GF5 GEOLOGIC FEATURES DOWNSTREAM OF CENTERLINE FIGURE 5.ll w f- a:: 0 0 I _j_ I I I i I I I I I I I I I I I I I I I N \ ~ \~,. TALt:IS 2 ...... ·,_ E w JOINT PLOT UPSTREAM PORTAL AREA N"540 s \ \ \ ' PHOTOGRAPH "\". \ \ \ \ E 747,500 '\\ " UP-2 ... ALLUVIUM PliOTOGfcAPH FIGURE. 5.15 -··"'1., ~l ~.l "THE FlN.S" AREA OF ~AJOR SHEARS, FRACTUReZONES AND Altt:RAT'.ON ZONES. . ----·-- ·---·"·-· UP-I ..ttl AllU\IIUM p ··. 75 78~YJ t TAlUS .2 LEGEND LITHOLOGY: SURFICAL DEPOSITS: ALLUVIUM TAlUS I, AREAS OF THIN VEGETATION, GREA7ER THAN 50.,_, OF TAl.US EXPOSEO. TALUS 2, AREAS OF DE.NSE Vt;GETATION, LESS THAN 50% OF TALUS EXPOSED. [ .•.••. ') DIORITE TO QUARTZ OlORITE INCLtn::e; ~· . _l MINOR GRAN DIORITE. [' , __ ,..., DIORITE PORPHYRY -X-FELSIC DIKE. CONTACTS: -BEDROCK. BEDRCCK /SURFICIAl. n£1>0SITS • ·--DASiiED WHERE ~:O.'<lMATE. ~---SURFICIAL DEPOSITS, -'"~>PROXIMATE STRUCTURE: ~~"]} . ''!.EAR, WIDTH GREAtt··· -R THAN 5 ,..!£::; .. ~ A.R-VERTICAl.. TO \'S:RTIC.!.!.. tiNr..E:S$ •• •... ~·" SHOWN; EXTE~T' i\-'NE,q£ K~ ~ 1 1 OR INFERRED. 7!0 ·~· SHEAR, WIDTH FRO»; ~ TO 5 FEET. INCLINED , VERTICM. !ilNLESS otF ~. • • SHOWN, EXTENT W~'li:'E KNOW A.W.'~ I J INfERRED • r:"-'~~ FRACTURE ZONE, ~~TN GREATE..':i: L.;:. ::::.;;t THAN 5 FEET, NEAR-VERTICAL re .. VERTICAL E:XTENT ~~~~ ~"'W~ ~- / 1 OR INFERRED. 72/ . .{ FRACTURE zo_ NE, W:'l>TH FROM l :C 1 "!" 5 FEET, !Nl!LINEO, \'~TICAL> ~ / . / WHERE Kt.!!J"-'N ANI)( ® INFERP.Ei:l" "') J. Af. JOINTS: INCL.INEO,.~ lNGUNEO 7 l:fo~ AND VERTICAL. l i!, SLUMP lN SURFICIAl lOe:l>OSITS. OTHER: UP-I Jt, ~ GEOLOGIC SECTION ~T!ON. ~ GEOLOGIC FEATURE t::l{$CR.IBEO !ill ~'V SECTION 5. SPRING. NOTES 1. LOCATION OF EXPLORAT\Om VN FIGURE :S:. 2. GEOLOGIC SECTIONS ON. ~l~~E 5.13 3. JOINT PLOTTING METH0£.1-~ FIGURE S.S 4. TOPOGRAPIW FROM COE, r~}S., 1",.200" 5. APPRO:'ltAATE EDGE OF R:>,l:\1~, AUGUST 1982. 6 SEISMIC LINE SECTiONS l~ :.\PPENOIX C AND A.A.!., 1982. 7. EXTENT OF SHEARS ANO ~CiUru:: Zt::l~ ARE INFERRED BASED ON' ~tOLOGIC MAPPING AND SUBSURFAC~ ~'XPLORAT!G!'Il~ AND ARE SUBJECT TO Va\~fiCATION THROUGH FUTURE OETAI"-~'tl INVEST!GA7':~. 0 40 80 FEET SCALE ~22!~~§iiiiiiiii~i ,/ c ·" . , .. ./.7 FIGURE 5.12 I I i I I I I I I I I I I I I I I I I I I I z 0 fi > w -' W. PROJECTED 90'NW ~LIJS -·--TREND o9o0"-- ® "THE FINS« 1 'rr , : AREA Ot OPEN JOINTS rAND LOOSE:, UNSTABLE ROCK I t l UMIT ~ I lj ~g~TAL H 1 !1 ~\ I fJ ri\ . r1 ., ) ~~·· ··.· -·~. . . ., .. · ~· ... • oo· , ' •• • ... 265o ..,..____,AZIMUTH _,.. oo OF SECTION LOOKING UPSTREAM .... TALUS AND ALLUVIUM 0.'\/ERSION ---1 [··1 -· ---r , ~~rEL 1 _J:~1 m.· L . _ 1.. SUSITNA --· ----l i.t-·-r-.J -.. ~ --J .1/ ,, I RIVER ·---------------+~ AREA OF OP~N .JOINTS AND LOOSE,UNSTABLE ROCI< TREND 315." 1 q ll ., lf \.'f ....... . 't·····.·.1. l'J TRENO 32. 5° ; TREND \:. : .• ,-~·.·:~ ·• •• ;:: Ul Ul u. ~ z 0 i= § IJJ .J w TREND 325• ~ Ill . 1~ V ·.· . 1 ...... ~""'··· I I .r· 3400 "~ t<.,.t.: .. y!.~· ~~ ·-~."./ l ~ .• ~ SECTION UP ·I PROJECTED 95' N SLB!-5 t 288" ~AZIMUTH__... 108 .. OF SECTION . LOOKING UPSTREAM ·-@) ,--------·--------"THE fiNS" [COFFERDAM CREST ELEVATION 1545' ----------------------L-----------------------------------------=-sL~S~2~-,5~------.r~~~ SL81•4 SL8t·5 t · -;,-.7 ·-·~~ SUSI'TNA RIVER------.. ,.roror--..:...· G /EL BAR ""lor s~~~~A ~~ ~ r .. .;;.;--9<;00FPS ALLUVIUM I .· ..... ; ·· .. ·,.:~~ALLUVIUM r-::=-=-=--.=-~--= ... -.:=_:-?~:-r-=-~.-.=.~--=_-:= .. = .. -... ~<::-;·.~:;!~r./~r~(·~· .~-:_.~._.~:-.:~1:i•1:_~~~.f~~.~·._.~;.:~;·~~~·~·~~"?i. :~j.:s: .• ~i~~:;'J;~~· :\ .. ·:::\: .. _~~;.~·;0p~.'~fTtJ• .•• ~·. ~.~~-,: :/;;;x>~ ·~000 FPS \ :< · · 12,ooo'hf:f:P£ · •· ·' · :·: · : ·· ·· · · ·: ·. · ·' ·;. · ./7 \I~.~\~~~~.···· di0;2S;:·:~~t~:~~~~:::~;/~ \ 17000 FPS v:-._,'~.t\ ~_II:: \ TREND 325° \ Y\ ~ PROJ.ECTED '~II PROJECTED ~n ~ ~- SECTION UP3 WATANA DAMSITE UPSTREAM COFFERDAM AND DIVERSION PORTAL AREA GEOLOGIC SECTIONS J 1800 1600 ~ 1400 ~ > w -' w LEGEND LITHOLOGY: Ei] . . SUR!"'ICIAL DEPOSITS, AU.Il..V.l,IM AND TALUS . !J DIORITE TO QUARTZ otOR•TE, INCLUDES t.tm.u:m 'l GRANODIORITE. l -X-FELSIC DIKE. CONTACT: -----BEDROCK/SURFICIAL DEFC:SlTS, APPROXIMA.~ STRUCTURE: I r. :··,:-:?"~.· SHEAR, WIDTH SHOWN WHE'!'i:E GREATER THA:f • L..:.. ~ 5 FEET. I [ ''7 1 FRACTURE ZONE, WIOIH ~WN WHERE .,:...;.J GREATER THAN 5 FEET. GEOPHYSICAL SURVEYS: 'fsLBI-5 INTERSECTION WITH SEt~ REFRI" , -:U::: SLSI-4 1981, WOODWARO-CLYbE C'ClNSLIL• SL82·15 1982, WOODWARD-CLYOE :t)NSULTANTS. • • • • • SEISMIC VEL.OC> (Y CflANG~. 5000FPS SEISMIC VELOCITY IN ·FEE:':' i'>E'R SECOND. OTHER: s GEOLOGIC FEATURE OESCR !~ttl IN SECT!OIIl ": NOTES: l. SECTION LOCATIONS SHOWN Cii'o:.;; ,l",..JRE 5.12 2 VERTICAL AND HORIZONTAL SCALE.::. li:ClUAL ~. SURFACE PROFILE FROM !"z2QO' ~~t'OGRAPHY COE,I978. 4. SEISMIC UNE SECTIONS SHOWN IN ~1'>J:>tNOIX 0 AND A A. I., 1982. 5 EXTENT OF SHEARS, FRACTURE Z~$ AND ALTERATION ZONES ARE INFERRE:.::', "'ASED ON GEOLOGIC MAPPING AND SUBSURRto::E: EXPLORAT!O.E AND ARE SUBJECT TO VER!FICAT'~,"4 THROUGH FI.;,'T"o.l"E DETAILED lNVE.'\TfGATIDNS 0 i!O SCALE e.::!:.~ 60 FEEr =• FIGURE 5.13 I I I I I I I I I I I I I I I .j I I "' I I NOTES. I I I I I DIVERSION TUNNEL ALIGNMENT NO.I NO.2 I , ... I ALLUVIUM UPSTREAM COFFERDAM CENTERLINE OBLIQUE AERIAL VIEW LOOKING SOUTHWEST I. GEOLOGIC FEATURES DESCRIBED IN SECTION 5. 2. LOCATION OF PHOTOGHAPH SHOWN ON FIGURE 5. 12 3. PHOTOGRAPH TAKEN S£~PTEMBER, 1982. W''ATANA DAMSITE GF IL· AERIAL 'viEW Q)F UPSTREt~~~ PORTAL AREA FIGURE 5.14 DIORITE GF IE GF IC SHEAR CONTAC'T GF IB otORITE PORPHYRY I I I I I I I I I I I .I I I I I I I I GFIL I . NOTES: DIVERSION TUNNEL NO.I {APPROXIMATE LOCATION) l. GEOLOGIC FEATURES DESCRIBED IN SECTION 5. 2. LOCATION OF PHOTOGRAPH ON FIGURE 5.12 3. PHOTOGRAPH FROM COE, 19.78. • ~ ·.' • ~ • ~ \ • j ·~ : • ' • -:--'!: . . ~ . ' .. ·, . . . . "\ . : . ~ . . ·-. . : ·-. .... . -. ~ . - DIVERSION TUNNEL N0.2 APPROXIMATELY 50 FT. BELOW RIVER LEVEL GF!C VIEW LOOKING WEST GFIB WATAN,A DAMSITE PHOTOMOSAtC OF UPSTREAM PORTAL AREA SUSITNA RIVER Fl~' '~E 5.15 I I I I I I I I I I I I I I I I I I E s SET .llT SET~ I SET I N JOINT PLOT DOWNSTREAM PO.RTAL AREA '·· ·-· -. Na411 TALUS 2 TALUS Z DP-r ·\. ALLUVIUM tAlUS 2 so NOTES I' LOCATlON OF EXPLORATIONS SHOWN ON FlqiJRE 3.1. -2) GEOLoGIC SECTIONS SHOWN ON FIGURE 5.17. 3) JOINT PLOTTING M£THOD ON FIGURE 5.8 4) TOPOGRAPHY FROM COE, 1978,1"~2DO' 5) SEISMIC LINE SECTIONS IN APPENDIX 0 AND AAI,I982. 61 EXTENT OF SHEARS AND FRACTURE ZONES ARE INFERRED BASED ON GEOLOGIC MAPPING AND SUBSURFACE EXPLORATJQI;S AND ARE SUBJECT TO VERIFICATION THliOUGH FUTURE CiiTAILEO INVESTIGATION ALLUVIUM LEGEND LITHOLOGY C:=J SURFICAL OEPOSJTES: -x- CONTACTS AU..UVIUM,INCLUOES UINOR AMOUNTS OF ANGULAR TALUS !>IATEF;IAL. TALUS •• AREAS OF TRIN VEGETATION,. GREATER THAN 50%c OF TAWS EXPOSED. TALUS Z,AREAS OF DENSE V~GETAT":it'{,.. LESS THAN 50% OF i'AL.US EXPOSC:D. DIORITE TO QUARTZ DIORITE , INCLUOES MINOR GRANOOIORITE: ANDESIT.E PORPHR't,iNCLUD~ MINOR DACITE M~D LATITE. FELSIC DIKE •. ,,. BEDROCK, O~)'IEO WHER~ APPROXIMATE. '"~--~--BEDROCK /SURFICIAL lJe'OSITS OASHED WHERE APPROXIMATE --· --·· · SURFICIAL DEPOSITS, A??ROXIMATE. STRUCTURE ~ SHEAR;W!DTH GREATER "niAN 5. FEET, .N~ VERTICAL TO VERTICAl.. ~ESS OIP ~ EXTENT WHERE KNOWN ~NO/OR INFERRC 70 /SHEAR, WIDTH FROM 1m·~ FEET,INCLINEC,, . Y.,.....-vERTICAL, EXTENT WH£RE KNOWN ANO:t :a ./ ...... INFERR£0. / FRACTURE ZONE, WIO"ffi GREATER THAN' I [ '] 5 FEET, NEAR VERTICAl. TO VERTICAL . L. UNLESS O!P SHOWN, E'.liTENT WHERE .. KNOWN AlllD/OR INFEft~ ~ ~/ .• FRACTURE ZONE, WIDT~ ~M I 'TO 5 fEE"l'::, .._?' *' INCLINED, VERTICAL; E~-n:NT WHERE l<NQI(JW -" /' AND I OR INFERRED. ~h JOINTS; INCLINED, OPEN: 1~CLtNEO, VER~ . ~ BEDROCK .cilUMP <!:~)GEOLOGIC FEATURE OE:S::RIBEO IN SECTICN. 5 . 9 SPRING I I I I 1- I I I I I I I I I I I I I I § IJ.. z 0 ti > Ul ..J Ul z 0 ~ UJ ....! UJ 1600 1600 075o..,.__ AZIMUTH __.,. 2550 OF SECTION LOOKING UPSTREAM SECTION DP-1 057c ...._ AZIMUTH ~ 237o OF SECTION LOOKING UPSTREAM SECTION DP-2 l SUSITNA RIVER § IJ.. z 0 i= ~ l.t.l ....! 11! WATANA DAMSITE DOWNSTREAM COFFERDAM AND PORTAL AREA GEOLOGIC SECTIONS SHEET J OF 2 LEGEND LITHOLOGY: SURFICIAL DEPOSITS: ALLUVIUM AND TALUS. DIORITE TO QUARTZ DIORiTE, llitCLUOES Ml~lCR GRANODIORITE. -X-FELSIC DIKE. CONTACT: -----BEDROCK/SURFICIAL DEPOStTS, APPROXIMATE- STRUCTURE: L--;] ~Hft&WIDTH StiOWN WHERE ~REAlER THAN [ •• ......, FRACTURE ZONE, WIDTH SHOWN WHE:RE .. ~--i_ GREATER THAN 6 FEET. GEOPHYSICAL SURVEYS: fst.SZ-1 INTERSECTION WITH SEISMIC REFRACTION LINE., SL82-I 1982, WOODWARD-CLYDE CONSULTANTS. SEISMIC VELOCITY CHANGE. f:.)OO FPS SEISMIC VELOCITY IN FE:ET PER SECONO. OTHER: § GEOLOGIC FEATURE DESCRi&:O IN SECTION 5' NOTES: I. SECTION LOCATIONS SHOWN ON F"..stJRE 5.16 2. VERTICAL .AND HORIZONTAL SCALES EQUAL. 3. SURFACE PROFILE FROM 1"•2001 tot>OGRAPHY COE,I978. 4. SEISMIC LINE SECTivNS SHOWN IN APPENDIX D. 5. EXTENT OF SHEARS, FRACTURE ~ AND ALTERATION ZONES ARE INFERRED. BASED ON GEOLOGIC MAPPING AND SUBSURFACE EX!"LORATIONS AND ARE SUBJECT TO VERIF'GATION 11-IROUGH FUTI.JfiE DETAlLED INVESTIGATIONS. 0~~~4~0iiiiiii:iiii8~0 FEET SCA\.E E! iiiMI FIGURE 5J7 I I I ·I I I I I - I I I I I I I I I ·:;;: ~ 1600 ~ w .J w § ~ z Q ~ > w .J w 1500 L le I. TREND 295" 057o,..._ AZIMUTH ---..257 o OF SECTION LOOKING UPSTREAM SECTI0N DP-3 034o..._ AZIMUTH ___. 214 o OF SECTION LOOKING UPSTREAM .... --....... •GF 70) .PROJECTED '··-·· · so's TREND· o• .' / ~') "FINGERBOSTER" ·-----AREA OF SHEARS, _ .. ··~- FRACTURE ZONES AND ALTERATION ZONES SE\::TION DP-4 <§ AREA Of EXTENSIVE ' OPEN JOINTS "- l• TREND 355• i i WATANA DAMSITE DOWNSTREAM COFFERDAM AND PORTAL AREA GEOLOGlC SECTIONS SHEET 20F 2 .t:!Q.li: I. EXPLANATIOtJ FOR SYMBOLS ON SHe.T I. 0 FIGURE 5.17 I I I I I I I I I I I I I I I I I I I .:> >-a: )- :r a. a:: ~ w .... (f) L&J c z <( 1.tJ r--tJ:: 0 -c l 1 -1 GF7Q AREA OF EXTENSIVE OPEN JOINTS AND LOOSE UNSTABLE. ROC!(. NOTES: I. GEOLOGIC FEATURES IN 11 FINGERBUSTER 11 AREA DESCRIBED IN SECTION 5. 2. ANDESITE PORPHYRY / DIORITE CONTACT ALONG GF7Q SHEAR • 3. SHEARS WITHIN GF7 TREND FROM UPPER LEFT TO LOWER RIGHT. WATANA DAMSITE "FINGERBUSTER 11 AREA NORTH BANK FIGURE 5.18 I I I I I -I I I I I I I I I I I I I I GF 7R GF 7R VIEW LOOKING NORTHWEST ALONG STRIKE OF ZONE. NORTH BANK-ELEVATION 1850 FT. NOTES: I. GEOLOGIC FEATURE DESCRIBED IN SECTION 5. 2. JOINT SET :rsz: DIPS TOWARDS SUSITNA RIVER. 3. JOINT SET I PARALLEL TO GF 7R WATANA DAMSITE TYPICAL SHEAR /FRACTURE ZfJNE '* FINGERBUSTER 11 AREA I FIGURE 5.19 I I I I I I I I I I I I I I I I I I I ANDESITE PORPHYRY NOTE: -I_. GF 7J VIEW LOOKIN3 NORTHWEST ALONG STRIKE:" OF SHEAR RIVER LEVEL -~'IORTH BANK GEOLOGIC FEATURES IN THE .. FINGERBUSTER u (GF 7) AREA ARE DESCRIBED IN SECTION 5 • WATANA DAMSITE SEOLOGIC FEATURE GF 7 J 11 FINGERBUSTER" AREA 1 DIORITE FIGURE 5.20 I I I I I I I I I I I I I I I I 2ll50.7 2140 2124.7 2120 2100 2.!80 2060 1-w w .... ;2.040 0 i= ~ w ..J w 2020 1980 1960 1940 40 80 1-w w IL 120 w _J 0 :r z ~ 0 0 i!: 160 a. w ..::> t STICK UP-4.4 FEET ( IA!Il DIP-ss• tlt-n-a!l +BOTTOM · OFSTRING 1608.8~ 1601.9~ 1580 1560 1540 80 1520 1-w 1-~120 :::: 1500 w IL _J 0 z :::: 0 z i= ~ ~· 1480 0 w 0 ...J w .:::: 1-160 D.. w 0 1460 1440 200 1420 1400 240 APPARENT FAILURE OF THERMISTOR , , POINTS WATANA DAMSITE THERMISTOR DATA SHEET I OF 2 4 . t ~ ~ F F ~ ' \ BOTTOM OF • \ STRING BH-6 LEGEND LITHOLOG'f: ~ GROUND SURFACE . ~ TOP OF ROCK BOREHOLES: AP OH OR AH BH AUGER BORING I OJJ,.;...·~p CORE BORING CORPS OF :£NGJNEERS tl9?8} ROTARY DRILL HOLE AUGER HOLE! ACRES AMERICAN INC:Z'!RPORATED BORE tlOLE ( 1980 -1~;1!) DATA SYMBOLS : ENVELOPE SHOWING RANGE OF OBSERVED TEMP~"¥RE& NOTES 0 OOSERVS:: <\eTJVEZONE (MAXIMUM t>~PTH OF ANNUAL ~ZINGITHAW11!1Z:O.~ -l-------· DEPTH OF: ::!ERO ANNUAL .liltll!"l..lTUOE I LOCATION OF BORINGS SHOWN ON FIGli.~$ ~.I AND 3.2. 2. THERMISTOR STRINGS MANUFACTURED. S'f' INSTRUMENTATION SERVICES IN FAIRBAN~. Al,ASKA 3. BORlNGS 8H·3, BH-6 ARE PERMANENT Ml~4.Tl·POINT THERMISTOR STRINGS WITH TWO THERMI.S;"::'~ AT EACH' READING POINT. DATA FOR TWO POINTS; c:$ AVI:.RAGEO. ALl. OTHER t!ORINGS AR~ PVC: PIPE, C~'j:iF>t;:O t..NO FILLED WITH ANTIFREEZE ( ETHYLENE ~;..".'.:;t:lt.) MIXTURE READINGS TAKEN WITH A THERMISTOR ¢JL.~t l'lTTEO WITH REDUNDANT (SINGLE PRIOR TO l~l\ THERMIS"roF.i:. 4. THERMISTOR READOUT BOXES MANUFACJl.in!;.~ 'SY l<EITHl ~ AND FLUKE, USED FOR 1980 THROUGH 19SZ: ~EAOINGS. 5. TOP OF ROCK I:LEVATIONS SHOWN ONto.~ WHEt.' ENCOUNTERED. 6. BORINGS ARE VERTICAL UNLESS A DIP!$ $-HOWN. -.'!/ •2 -1 0 SCALE. ( I I : I I I I I 'l I I I 27 28 29 30 31 32 33 .S4 35 36 r' "F FIGURE 5.21 I I TEMPERATURE (•c) TEMPERATURE (•c} TEMPERATURE (•c) -3 ·2 •I 0 I 2 3 4 ·3 -2 -I 0 I 2 3 4 •3 ·2 -I 0 I 4 1950.9 0 1480.0 0 195[.5 0 1941.4 1946.6 I 1940 STICK UP· 1460 STICK uP• STICK UP-1.!! FEET 2.0FEET 1.0 FEET 1920 (1978) E {1978) (1978) DIP-57.6• OIP-45• 40 ~40 40 I 1440 w 1920 I .... 1900 0 ::t: j:: 2: IIJ ~ ~ 3: j:; w i I ~ 0 1&. t-omE UJ Q w '"" UJ w w w 1&. lJJ I ~ 1880 ~ -1420 .!!:1900 .... I z z 0 ;z 0 ::t: I 0 zSO 0 ~1408.7 ti j::. 3: ~ 1860 > 8 I ): z w w l ;It .... 1400 .... t ~ 0 w w ·I w Q IS SO I ::1: UJ I I 1-Q I a. l w :• Q 1380 -120 ! " ' I 1860 t BOTIOM OF PIPE ONLY ONE READING OSTAINI!O 1 ISOOL BELOW 20 FEET (FROZEN! 1 1360 NO WINTER READINGS.- NO WINTER READINOS-FROZEN SOLID FROZEN SOLID I 160 160 18401... !60 DH-~R Ofi-21 DH-2~ I I TEMPERATURE (•c) TEMPERATURE (•c} TEMPERATURE t•c) •3 •I 0 I 2 3 4 -3 -2 -I 0 I 2 3 4 ·3 -2 -I 0 I I ~ .... f 0 l 2044.9 ~ 0 / 1971.0 0 2054.5 ! 2040 1961.8 ' t ST!Cl< UP- ' STICKUP-STICK lJP· 2040 ~ I 1,0 FEET 4.0 FEE'> J.OFEET (1978) (JULy, 19801 1940 (19781 2020 DIP·44° 2020 40 40 40 1920 I j:; ~ ...... w w ti -20Cl0 w t:"2ooo w t=: w 11. ~ ~ .... w w w ! w l1l ~ 1900 ~ w w ~ ~ .... I ..J ~eo z 0 0 ~ 1980 0 :I: 80 ::t: 80 I i l i= z ~ i 3: ~ 8 rTroMOf"PE ~ 0 LEGEND SHOWN UN FIGURE 5.21. > ~ 1980 Q w ::t: .X ~ ...l J-w 1-11.1 Q.. Q. Q. 1960 :g w 1!:1 Q I I 1860 -a -2 -1 0 t 2 <!"'C SCALE 1 I I I I ! I 120 I 120 J I I I I , 4 I I 120 1960 BOTIOM OF PIPE 27 28 29 ao 31 32 33 34 35 36. 5:" ,..,.. .. J ·! ··-·-·-_j I ~ 1840 ! I 1920 I ! .J NO READINGS OBTAINED I • i BELOW 25 FEET(FROZEN) ! 1820 I 160 1900 160 160 '"'""' ___ ,.,_.,_..,."", ., ___ .. _ -...L......:-· -,..., ... _,_,;_....._.. ___ -="-''""·'"-)<""'• I OH-24 OH-25 OH'-28 I WATANA DAMSITE THERMISTOR DATA .J SHEET 2 OF 2 I FIGURE 5.2.1 I I I I I I I I I I I I I I I I I I ·I 6 -RESULTS OF GEOTECHNICAL INVESTIGATIONS -WATANA RELICT CHANNEL 6.1 -Introduction During the course of investigations carried out by the COE and Acres, subsequent studies in 1980-81 confirmed thr existence of a possib1e buried relict channel running from the Susitna River gorge from imm~di ately upstream of the proposed damsite to Tsusena Creek, a distance of approximately 1.5 miles. fhe major potential problems associated with the relict channel are: -breaching of the reservoir rim resulting in catastrophic failure of the reservoir; and -subsurface seepage resulting in potential downstream piping and/or 1 ose of energy. Breaching of the reservoir rim can be caused by saturation of the un- consolidated sediments within the channel resulting in surface settle- ment or by liquefaction during an earthquake. Excessive subsurface seepage can be caused by highly permeable unit(s) within the channel that would provide a continuous flow path between the reservoir and Tsusena ;::reek. As a result of these potential problems, a geotechnical program was undertaken during 1980-81 (1) to obtain a b~tter understanding of th~ channel configuration and geology .. However, due to excessive depths of the channel (>400 feet), difficulties of drilling through bou·ldery material and logistical and cvst constaints, no information regarding the deep stratigraphy of the channel was obtained during 1980-81. Therefm'e, Acres undertook supplemental investigations to includ.:! drilling, field mapping, laboratory testing, instrlJTlentation installa- tion and seismic refraction surveys during the summer 1982 season (Figure 3.2). Additional deep drilling and seismic investigations were also planned to complement the summer investigations during FY 83.. The objective of tl,ese investigations was to refine the stratigraphy of the Watana Relict Channel/Borrow Site D area; determine material properties of the st·rata; and provide information on the permafrost and hydro- geological conditions. Results of these investigations are presented in the following S·ection. A surficial geologic map of the area is shown on Figure 6.1. Fi-gure 6.2 is a generalized stratigraphic column for the \~atana Relict Channel/Borrow SiteD area. The correlation of this stratigraphy across the area is shown on Figure 6.3 and 6 .• 4, wi-th photographs of these waterials in Figure 6.5. Contour maps of the various stratigraphic units is in Figure 6.6. The information pre- sented here supersedes that information presented in Section 6 .. 2 of the 1980-81 Geotechnical Report (1). 6-1 6.2 -Location and Configuration The Watana Relict Channel, as defined in this report, is located be- tween the present ·course of the Susitna River and Tsusena Creek, and fills an area from the emergency spillway location (Figure 1.2) to Deadman Creek. Borrow Site 0 is located in the southeast quarter of the channel and overlies the major portion of the inlet area near the Susi tna River. The location of the channel is shown by the top-of-rock map presented inFigure6.7. The ground surface in the relict channel area is hummocky with a drain- age divide trending generally north to northeast through the area which closely corresponds with seismic lines DM-A and [lvl-B (Figure 3.2). The maximum overbufden thickness in the thalweg channel is approxi- mately 450 feet (Figure 6.4). The distance between the proposed reser- voir and Tsusena Creek along the shortest distance through the channel is approximately 6, 200 feet and about 7, 700 along the thalweg section (Figure 6. 7). The thalweg course is somewhat irregular, diverting from the Susitna valley downsteam of Deadman Creek at a point near seismic 1 ine SL82-22. The channel trends with an uphill gradient parallel to the Susitna River to a point near AH-030 (see Figures 3.2 and 6.7). From AH-030, the chant~el d·ive;--ts north~Jester1y, with a stee!l downward gradient, to a bedrock low located northwest of DR-22 (Figure 6 .. 7). Bottom elevation of this pool has been estimaterl from seismic refrac- tion data and borehole DR-22. Beyond the pool, the channel runs thro~tgh a narrow gorge r1s1ng to an elevation of approximately 1,800 feet from where it continues to its confluence with Tsusena Creek (Figure 6.7). Minor tributaries to the Watan a Re 1 ict ·channel are found near Tsusena Creek. These. tributaries flow in a southwesterly direction, and may be partially joint conb"olled (Figure 5.8 and Section 5.1 [c]). A buried waterfall appears to exist in one tributary, immediately adjacent to Tsusena Creek. Details of the paleo-drainage regime, and the sequence of events lead- ing to the formation of the -relict channel are given in Section S.4. 6.3 -Stratigraphy of the Hatana Relict Channel/Bo[row Site 0 f Twelve stratigraphic units have been delineated in the Watana Relict Channel/Borrow SiteD area (Figure 6.2). These units (denoted as Units A through K) are differentiated by theh~ physical properties, as iden- tified in tr; field, and their material characteristics. Cross sec- tions and a fence diagra~ of the relict channel are shown in figure 6.3 and 6.4. Photographs of the typical units and top of unit maps are presented in Figure 6.5 and 6.6. Surficial distribution of those units is indicated on Figure 6.1. 6-2 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Field 1dentif'cation of these units was basedJ on drilling, in-hole testing~ mapping of outcrop exposures, and geomorphology. Distinguish- ing properties include color, grain size, roundness of particles, com- paction, imbrication, composition, 1 ithology, sorting, weathering and striations. Material properties obtained from laboratory tests on sam- ples from drilling and bulk samples taken from exposures along Tsusena and Deadman Creek included grain size, moisture content~ Atterberg Limits and composition of sample wash residue. Typical stratigraphic unit .gradations and standard penetratjon test data for the.se units are shown in Figures 6.8 through 6.10. The unit breakdown has been based on specific modes of deposition (i.e. glacial advance, retreat, ablation, e.tc.). Due to the complexity of glacial and paraglacial depositional environments, wide variations in material properties and physical characteristics within specific units are encountered. However, for the most p.art, these variations are in- dicative of localized facies changes and/or local imomalies within the unit and have, therefore, been classified within the overall unit,. Detailed ~iscussion of material properties of Units A through F are presented in Section 8 .. 2. The following is a brief description of stratigraphic units used in delineating the stratigl'aphy in Borrow Site 0 and the relict channel. As additional information is co.llected, refinement of the unit breakdown is likely. Table 6.1 and 6.2 list the interpreted depth to the top of stratigraphic units and the unit thick- ness. (a) Unit A/B -Surf:ci al Deposits (b) Unit A/B is the uppermost unit found in the area, and consists primarily of frost-heave cobbles and boulders, organic silts, peat and muck. fhis unit forms a thin, discontinuous veneer (0-7 feet thick) that has been subjected to post-glacial erosion, frost heaving and vegetative d2composition.. Its composition is vari ... able. In undrained lowland areas, Unit :4./B consists of peats and organic silts, while in drained low areas, it often consists of large boulders and cobbles which have been raised to the surface by frost action. Such boulder fields are found frequently across the site, and were likely formed wi~.nin a paraglacial environment where the fine material has been washed away. In higher areas un- derlain by shallow bedrock, the unit is <}enerally thin or absent. Unit C -Ice Disintegration Deposits Unit C is an ice disintegration deposit forming a discontinuous mantle across the .Watana Relict Channel/Borrow Site D area. This unit ·is geomorphically expressed as a knob and kettle topography, typical of ice disintegration terrain. Local knobs of Unit C generally range from 5 to 40 feet thick. The unit is found most frequent 1 y in the northern portion of the area, where it forms moraine-type ridges, while it is often absent in the southern pm~ tion of the area toward the Susitna River (Figure 6.1). Being near surface, Unit Cis easily identified in the field ana on air photos by its hummocky topography. 6-3 (c} (d) (e) " The unit is composed qf tan to brown silty sand with subangul ar gravel and cobbles throughout (Figures 6.5 and 6.8). The unit is generally poorly sorteci~, although local areas of sorting are pre- sent due to flowing warP.r during ice melting. Some pebbles and cobbles are weakly striatP.d-The degree of compaction is variable though generally, densitj te,.~ds to increase with depth •. Unit D -Alluvium Unit D is an alluvium found locally as confined channels within .. ne upper surface of Units E/F (Figure 6.6) (Section 6~3 [f] and Figures 6.1 and 6. 3). It is occasion ally found near the ground surface where Unit C has been eroded by present day drainage. It is most extensively found within the Watana Relict Channel area, and is less common in Borrow Site D. The unit is composed of stratified sand, silt, gravel and cobbles in sorted layers (Figure 6.5)e Particles are generally rounded to subrounded, with coarse material generally found in a matrix of sand and silt. Thickness of the unit varies· from 0 to greater than 40 feet. Unit 0' -Lacustrine Deposits Unit f)' is a discontinuous lacustrine unit found locally across the watana Relict Channel/Borrow Site D area. These 1 acustrine deposits have been observed in thickness from 0 to 21 feet, and are principally found '~dthin low areas of the upper surface of Unit E/F (Section 6. 3[f]). They are occasionally overlain by Unit D but can also be found directly under Unit C. No surficial ex- posures of the unit have been found. The unit is generally composed of a gray laminated clay which occasionally shows evidence of rhythmic deposition and varves (Figure 6 5). Local facies changes to silt and fine sand, which also show laminations and evidence of lacustrine deposition. Unit M -Basal Till Unit M is a basal till, found in the Borrow SiteD adjacent to the Susitna River valley (Figure 6.1). Unit M li~s stratigraphically between Units C and E/F ~ and ranges in observed thickness from 0 to 80 feet. The unit appears as a very dense gray clay matrix containing angu- lar striated gravel and cobbles (Figure 6.5). The unit appears similar to Unit G' in drilling samples. Examination of \~ashed sample residue indicates however, th~t the coarse fraction con- tains much more mafic rock types than does Unit &• {Section 6. 3[g]). No evidence of Unit M was found in the Watana Relict Channel area or in the northern portions of Borrow Site D. 6-4 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I (f) Units E/F -Outwash Units E/F form a thick mantle of outwash overlying most of the Watana Relict Channel/Borrow Site D area. This relatively contin- uous mantle contains an upper, low energy facies (Unit E), and a stratigraphic lower high energy facies (Unit F). Together, these units form a mantle of outwash averaging 40 feet thick (Figure 6. 6). These units are generally uniform in thickness in Borrow Site D, and thicken to a maximum of 130 feet in the Watana Relict Channel areae They are exposed extensively at the surface {Figure 6.1)~ in areas not overlain by ice disintegration deposits, Unit c. The upper facies (Unit E) is composed primo~ ily of an olive brown silt and fine sand matrix containing subangul ar to suLrounded gravel and cobbles throughout (Figure 6.5). Localized lenses of clean sand, gravel or clay are occasionally found. Size and con- tent of coarse material increase progressively with depth through the gradational facies change from Unit E to Unit F. The highe·r· energy facies (Unit F) is composed of a very dense orown to tan sandy, gravelly silt matrix containing rtumerous cobbles and boul- ders. Boulder and cobble content increase toward the lower por- tions of the unit, with a boulder zone frequently found at the base of the unit separating it from the underlying Unit G or G*. (g) Unit G -Glaciolacustrine and Waterlain Till (h) 0 Unit G is a relatively continuous strata of g1 aciol acustrine and waterlain c'Eposits found throughout the Watana Relict Channel/ Borrow Site D areae These deposits have been designated Unit G and, together with Unit G' (see Section 6.3[h]), form a strati- graphic marker horizon across the area, identified by their high clay content and gray color. Unit Granges in thickness from 0 to 74 feet {Figure 6.6). Gray to blue gray uniform, laminated clay (rock flour) comprises most of the unit, with rhythmic interb.eds of fine silt (Figure 6.5). Strong varving has developed in the clay at many locations~ Localized striated gravels and coarse sand are often found. At some locations, ice lenses up to six inches thick have been en- countered. A gradational facies change locally occurs between Unit G and G' as denoted by increasing amounts of striated gravels and poor·ly developed 1 aminations. In these areas, the unit appears to have been deposited as a waterlain till (see Section 6.4). Unit G • -Basal T i 11 Unit G' is basal till found in localized areas of the Watan-a Re 1 ict Channel and Borrow Site D. This unit forms a thick deposit trending northwest-southeast across the borrow area (Figures 6 .. 1 and 6.3), and is also found as isolated patches in other portions of the area (Figures 6.1 and 6.4). 6-5 The unit consists of subangu1 ar to angu1 ar gravel and cobbles set in a matr-ix of gray to blue-gray, very dense clay (Figure 6.5). Gravels and cobbles, largely granites and diorite:; are generally striated. Elongated cobbles often show imbricate structure within the matrix materials The matrix may contain varying anounts of silt and sand as well as clay. An upwa·rd gradation into waterlai,n and/or lacustrine facies occurs where Unit G' is overlain by Unit G. (i) Unit H -Alluvium Unit H is a localized alluvial and fluvial deposit, confined to channels in the upper ~urface of Unit I (Section 6.3[j] and Figure 6.6). This discontinous unit is found in both the Watana Relict Ch anne 1 and Borrow Site D area, a 1 though it is thickest in the Watana Relict Channel. Stratified, sorted sand, gravel and cobbles make up most of Unit H. Particles are ~enerally rounded, and often show some evidence of weathering to include 1 imonite and hematite staining (Figure 6.5). Alternating strata of sand and silts are found within interstitial spaces between cobbles. Organic matter, including wood, are: occasionally found in the unit. The unit ranges in thickness from 0 to 41 feet. (j) Unit I -Outwash ( k) Unit I is a stratum of outwash generally found directly below Unit G' or Unit H. This outwash is absent in many areas of the site, particularly in those areas of -Borrow Site D where bedrock is at a high elevation (figures 6.3 and 6.4). Thicknesses of the unit ranges from 0 to 75 feet, reaching maximum thickness in the Watana Re 1 ict Channel area. Subrounded gravel and cobbles in a very dense silty sand matrix make up most of the unit. fhe unit is w~athered in most samples, showing red-brown hematite and 1 1monite staining on particles, giving the unit a characteristic rusty color. Coarse fractions make up most of the unit. Some clasts show striations with some portions of the unit appearing as a ti'~l. A 1 acustrine facies,· composed of silt, sand or clay, is often found in the lower center of the unit (Figure 6.2). Unit J -Till Unit J i.s a discontinuous stratum of till found mainly in the area of the Watana Relict Channel, but occasionally in the Borrow Site D area (Figm~e 6.3). The unit varies in thickness from 0 to 62 fe.et. 6-6 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I The appearance of Unit J is similar to that of Unit I, being a rusty brown .color and very dense. It contains a large amount of angular and subangul at• gravels and cobbles that show some evidence of striations. Sampling of this unit is difficult due to its high density and rocky matrix. No exposures of the unit were found in the area. · (1) Unit J• -Lacustrine and/or Stratified Deposits Unit Ji was deposited from both flowing and standing water. The unit is generally confined to the Watana Relict Channel area, although it is occasionally encountered in borings in the Borrow .Site D area (Figures 6. 3 and 6. 4). It appears as fi 11 ing in the low topographic areas of the upper surface of Unit J (Section 6. 3[j]). This unit is composed of either stratified sands-, silts and gra- vels; or lacustrine sands and silts. Gravel fragments are gene- rally rounded with maximum detected thickness of 48 feet. (m) Unit K -Alluvium Unit K is the oldest and deepest unconsolidated deposit found in the Watana Relict Channel area and consists of an alluvium. These. deposits have only been found along the main thalweg of the relict channel and its related tributaries (Figures 6.3 and 6.4), princi- pally in t~te southeastern portions of the relict channel near the Sus i tna River. The alluviun is compo~i~d primarily of rounded boulders and cob- bles. Matrix material appears scarce or absent, and high dri11 water losses were encountered by the COE during the 1978 investi- gations. Little else is known of this unit due to its depth and difficult drilling conditions. 6.4 -Geologic History of the Watana Relict Channel/Bprrow Site D Area Based on the stratigraphy encountered during the geotechnical investi- gations, a sequence of geologic events during which the various units were peposited has been reconstructed. A proposed sequence of events was presented in the 1980-81 Geotechnical Report (1). Further investi- gations during 1982 verified much of the 80-81 interpretation; however) modifications and refinements were made to several stratigraphic units and the geologic events associated with their deposition. The geologic history, presented below, has been based on all investigations carried out to date by Acres and the COE (27). This geologic sequence is sum- marized in Figure 5.2. Additional drilling and testing proposed in the Watana Relict Char;nel for the winter of 1982-83 ha.-been designed to confirm and augment this interpretation. The information presented in this Section supersedes that which was presented in Section 6.2 of the 1980-81 Geotechnical Report (1). 6-7 If (a) Formation of the Relict Channel Some indication of the early Quaternary geologic histor·y of the area can be obtained from the topography of the bedrock surface, presented in Figure 6.7. This map has been based on extensive seismic refraction surveys and limited borings in the Watana Relict Channel and Borrow Site D area. This map provides some indication as to the possible paleo-drainage regime in the area. It appears that the former ... main drainage of t~e Susitna Rivet" fl ow,=d from east to west a 1 ong the north edge of the present Susitna River valley. At a point near SL82-22 it turned slightly northwest s cutting a channel generally parallel to the present river channel to a point near SL82-19 where it diverted north- westerly (see Figure 6., 7). It then flowed with a steep gradient toward the present Tsusena Creek, at which point it turned south- west, roughly along the pre~ent course of Tsusen3. Creek. This pal eo-drainage_ channel has been designated the ··~1atana Relict Channel 11 ; the term referring to the portion of the channel now filled with overburden, between the Susitna River and Tsusena Creek. A valley in the bedrock found along SL82-22 indicates the point at which the channel diverted from the Susitna Valley into the Relict Channel. Seismic lines OM-A, SL81-14, SL82-16, Sl82-18, SL80-20, Sl81-13, and SL82-17 (Figure 3.2) all cross the former course of the Susitna River (Figures 6.3 and 6.4). Drilling performed by the COE shows tnat the alluvium Unit 1<, 1 ikely represents the fluvial deposits of this former drainage regime. The cobbles and boulders within Unit K indicate the high energy deposition and steep gradient of the relict channel. A change in morphology is found in the lower portion of Tsusena c~~eek, downstream of the point of entrance of the relict channel,. Here, the valley wall slopes become more gentle indicating a more mature drainage system than that of the upper reaches north of the relict channel. This more mature drainage supports the postula- tion that this portion of Tsusena Creek may have been the down- stream portion of the formed relict channel where it re-entered the current flow regime of the Susitna. Other pal eo-drainage channels are ~.1 so evident in the bedrock dr·ainage in the area of Deadman Creek {Figure 6. 7). Several C11annel s, now primarily fi 11 ed with Units E and F (Figure 8. 2}, appear to have bePn smaller tributaries flowing into and parallel to Deadman Creek. The relationship of these sma11er channels to the Watana Relict Channel is not clear. The Watana Relict Channel appears to have incised to a depth of approximate Elevation 1800 before glaciation resulted in diversion of the river to its pre.sent location. 6-8 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I • I I I I I I I (b) Ear 1 y G 1 ac i at ion Following the incision of the Wat~ .. ~a Relict Channel, a major advance of ice moved through the ar~a filling in the relict chan- nel and smoothing the topography. This advance, which has been del ineate,:f as Gl ac i at ion J, was 1 ike ly a major advance that re- sulted in the deposition of the basal till Unit J (Figure 6.2). Based on the distribution of this till (Figures 6.3 and 6.4), the glaciation appears to have covered most of Borrow Site D and the Watana Relict Channel area. The degree of weathering displayed by particles of Unit J confirm the relative older age of this till to other tills in the immediate area. As the glaciation retreated, a paraglacial er."ironment of ponded 1 akes and braided streams developed in the area as evidenced by the deposition of Unit J', an alluvial and lacustrine deposit (Section 6.3). As expected in such a depositional environment, this unit is not present everywhere, but rather confined to localized topographic lows where water collected and f1owed .. ·As Glaciation J continued1 meltwaters deposited outwash Unit I (Figure 6.2) on top of Units J and/or J'. A minor readvance of the ice margin into this area may have occurred during this period as parts of Unit I have a till-like facies.. Melting and retreat of Glaciation J continued to deposit the remainder of ~he outwash to Unit I. It was probably during this time that the Susitna River cut a course somewhat parallel to its present course below Elevation 1800. The Watana Re1ict Channel was probably dammed by active Of' stagnant ice during the retreat of Glaciation J, while the river cut down along major joint sets (Section 5.1) through the plutonic body at the damsite to an elevation below the base of the Watana Relict Channel (Elevation 1800). (c) Early Interglacial Period Following deposition of Unit I, the area experienced an inter- glacial stade. Erosion took place with stream channels cutting into the upper surface of Unit I~ These channels became fi 11 ed with Unit H alluviume Evidence of an interglacial environment is given by organics and wood specimens found in the upper horizon of Units I and H. Some organics are also found in portions of Unit G. Drainage in the ~Jatana Relict Channel atea was likely to the south into the Susitna River and east and west into the present areas of Deadman and Tsusena Creeks. Drainage tributaries cut into the underlying unconsolidated materials and bedrock (Figw"e 6.7). (d) Middle Glaciation At the close of the interglacial period, a new ice front advanced across the area. This glacial advance, referred to as Glaciation G', is.represented by the basal till, Unit Gt. The dense no "e 6-9 (e) (f) and structure of this t i 11 indicates a thick ice mass. As melting occurred, a preglacial environment was developed. Drainage appears to have been blocked one or more times~ resulting in the formation of glacial lake(s) at or near the ice margin. Thick deposits of glacially derived mater·ials in Unit G are extensive throughout the area indicating the extensive size of the lake(s). Varves are common within Unit G. Coarse sands, gravels and ice rafted particles within this lacustrine unit indicate the close proximity of the ice margin during deposition. A transition between Unit G and G' contains features of both a till and of a lacustrine or waterlain till deposit. The basal till Unit G' is found only in localized patches, whereas Unit G glaciolacustrine material is extensive throughout the area (Figure 6. 3). This complex depositional rel atiortship may be explained by either: (1) parts of Unit G' were removed and reworked by watet"' as the 1 ake formed, or (2) the ice mass was not grounded every- where as it moved across the area, with G' only being deposited where the ice was grounded. As the ice mass retreated the glacial lake(s) drained. During this time,· water may have eroded some of the upper surface of Unit G (Figure 6.6) and deposited the thick outwash of Unit F. During this period, the ice margin was probably nearby, as evidenced by the large subangular particles found in Unit F (Figure 6.5). As the ice receeded, energy of the flowing meltwater decreased· resulting in the deposition of the finer facies Unit E. Units E and F represent the same event, but differ in the degree energy environment of deposition. Middle.Interglacial After retreat of the ice and deposition of Units E and F, the Watana Relict Channel/Borrow Site D area was again subjected to an interglacial period. During this time, erosion took place result- ing in surface streamflows and inception of lakes in lowland areas. Unit D alluvium was deposited during this period .. Based on the distribution of Unit D~ the topography of the area at that time appeared to be similar to that of the present. This indi- cates that major drainage patterns of the time followed similar· courses to those of Deadman Creek, Tsusena Creek and the Susitna River. Areas of standing water and lakes were also present during this time, as evidenced by Unit D1 • Localized Glaciation Concurrent with the interglacial period during which Units D and D • were deposited, a localized advance of ice occurred in the southeastern. por·tion of Borrow Site D. This advance deposited a compact basal till, Unit M. Based on the apparent distribution of Unit M (Figure 6.1), it appears the advance was confined to the 6-10 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I southeastern portion of the area~ since nc deposits of Unit M have been identified elsewhere in the area. This ice advance was like- ly either a valley type glaciation moving through the Deadman/ Sus itna confluence area, or altern at ivel y a tongue of ice from an advance originating in the south which moved no further into the area. The deposition of Units 0 5 D' and M appear to be concurrent, with the alluvial and 1 acust_rine Units D and 0 • being deposited during the time the localized g'laciation depicted by Unit M moved across a portion of the area. Units D and D1 represent the the parigla- cial deposition environment. Both units continued to be deposited during and after the retreat of the local glaciation, resulting in parts of Unit M bei~g covered by these units. (g) Last G 1 aci at ion At the close of the interglacial period represented by Units D and D1 , the Borrow Site D/Watana Relict Channel area was again glaci- ated. The glaciation overrode -surficial Units E and F, and minm"' areas of Units D and D'. This glaciation re-worked the uppe\" horizons of these units as it moved across the area. Later the ice became stagnated in the area, with ablation and melting exceeding accumulations at the source area. The stagnated ice mass wasted in-place resulting in the deposition of the ice disin- tegt"'ation Unit C (Figures 6.1 and 6.4). Since: (a) the material of Unit C was largely derived from the underlying Units E and F; and (b) the ice was not extremely active, deposits of Unit C closely resemble Units E and F in com- position. Due to this 40mpositional similarities, it is difficult to c1early delineate the Lasal till contact of Unit C with the underlying Units E and F. As the ice mass wasttd downward, meltwater resulted~ local1J re- working Unit D. Ice melting resulted in the hummocky knob-and- kettle features which form much of the present topography. (h) Post-Glacial Events Recent geologic events in the area are confined to post-glacial erosion and frost heaving, and are represented by Unit A/B (Figur·e 6.2). Major pust-glacial erosion occurred through resurrection of the Tsusena and Deadman Creek drainage channels, and the continued down cutting of these streams through bedrock (Figure 6.2). Ero- sion by surficial drainage has occurred, forming the present drainage channels found in the Watana Re1 ict Channel area, and forming the minor tributaries to the Susitna River. Frost heaving has raised coarse material to the surface. This material has, in some places, rolled into low areas, where it has been reworked by post-glacial erosion, forming the boulder fields frequently in the flat channels found across the area. 6-11 ( i) Summary The Quaternary historical sequence presented above closely cor- responds with other geologic studies performed in the Susitna River Basin. Work on this project by Woodwara-Clyde Consultants (40) independently came to the conclusion that the area had experienced a similar sequence of four glacial advances. These include: pre-Wisconsinian >100,000 years before present (y.b.p.); Early Wisconsinian, 75,000 to 40,000 y.b.p.; Late Wisconsinian, 25,000 to 9,000 y.b.p.; and Holocene, <9,000 y.b.p. The scenario presented in this section are substantiated by the field data. However, further detailed information will be neces- sary to. verify several areas of the interpretation.. Principal areas requiring further evaluation are: -Bedrock elevations in the vicinity of SL81-14, in the area of the apparent bedrock depression; and -Extent and continuity of several of the deeper units, particu- 1 ar l y Un it K. Acres believes the Hammer drilling program set forth this winter will greatly assist in further refinement of this interpretation. 6.5 -Ground water The ground water regime in the relict channel is complex and poorly understood due to the presence of intermittent permafrost, aquicludes~ perched water tables, and confined aquifers. Instrunentation installed during this program have not had adequate time to fully stabilize to provide any additional data relative to the ground water regime. Ini- tial readings indicate that some of the instruments may have mal func- tioned. Further verification of this wil 1 be required in FY83. Based on drilling it appears that possible artesian or confined water tables exist in Units H and J • while several other units appear to be unsaturated. A perched water table condit1on exists, at least locally, on top of the impervious Unit G, and possibly on top of M, I, and J. Limited permeability testing (Section 6. 7 [c]) indicate the range of average permeability in the mor·e gravelly materials is about lo-3 em/sec, whi 1 e the tills and 1 acustrine deposits can be estimated at about Io-4 to Io-5 em/sec. ·Systematic instrumentation of the various units will be necessary to determine the actual conditions in the relict channel area, but in general terms it appears most areas have a shallow water table, and the pervious units, with the possible exception of Unit K, may be under natural hydrostatic heads equa'l to or greater than planned reservoir 1 evel e 6-12 I I I I I I I I I I ·I I I I I I I I I I I I I. I I I I I I I I I I I I I I I 6.6 -~ermafrost Regime The permafrost and ground temperature regime as described in the 1980- 81 Geotechnical Report {1) remains relatively unchanged. Re-evaluation of the earlier drill logs and of the ground temperature envelopes from the thermistor· installations (Figure 6.11) has led to the conc1u~ion that most of the identified permafrost does not include solid phase water, but rather reflects mixed-phase m"' freezing temperature water. Very few of the borings noted as encountering permafrost in drilling (as detected by thermometer or visible ice) have frozen back to zero or freezing· temperatures upon stabilization. It is believed that the permafrost encountered in the Watana Relict Channel/Borrow Site D area is so close to ooc that there is not enough 1 atent heat capacity to refreeze after· disturbance. The active zone averages about 10 to 15 feet, reaching a 22 foot maxi- mum recorded depth. The zero annual temperature amplitude point ranges from 8 to 80 feet, but generally. average between 25 to 40 feet in depth. Maximum depth of permafrost:t continuous from the surface (based on boring logs) was about 40 feet, in Unit G. Isolated permafrost has been detected as deep as 240 feet (DR-22), but the deepest permafrost depth indicated by instrumentation is about 70 feet. It appears that most of the visible ice is confined to the annual frost zone in Units C, D, E and F; and to Units G, G' and H in permafrost zones. Unit G is the only place where significant ice lenses have been detected, ranging up to 6 inches in thickness, and locally comprising up to 50 percent of samp1 e volt.me. Average ground temperature at depth with the exception of several fro- zen shallow holes, run from +0.5°C to about +1.5°C, with the mean low- est temperature at depth probably being around +1 °C. Additional dis ... cussion on the shalluw permafrost regime is provided in Section 8.2~ 6.8 -Engineering Impacts (a) Introduction 0 As stated in Section 6.1 the principal impacts of the relict channel on project design is the potential of breaching the reser- voir rim and excessive seepage resulting in either downstream pipfng and loss of energy. Although the 1982 work has not totally eliminated these concerns, it did provide additional information in evaluating these potential JJ."oblems. The results and prelimi- nary conclusions derived from this program are presented b~low_ The FY83 winter drilling program has been designed to provide the additional data to confirm the conclusions set forth here. (b) Reservoir Rim Stabi 1 i ty Breaching of the reservoir~ rim may occur by either settlement and/ or s1~mping "nder static or dynamic conditions. Static failure may be either progressive or catastrophic. Several conditions must exist for slides to develop. These are: 6-13 -vJi despread re 1 at i vel y perv io:.Js 1 oose unconso 1 id ated materia 1; -Widespread permafrost in granular material; and/or · -Slide surface with gradients sufficient to cause movement. A slide occuring in the Watana Relict Channel is considered un- likely due to the following: (a) (b) (c) (d) (e) A low potential slide gradient exists in the narrow thalweg section near "The Fins" due to the rise in the bedrock sur- face in this area (Figure 6.7). A slide further upstream near Deadman Creek would require an extremely 1 arge quantity of material moving on a 1 mv gr·ad i ent to result in a breaching of the reservoir. Similarly, a failure on the Tsusena Creek side of the channel would 1 ikewic-· be on a low gradient and would involve a 1 arge val Lme of maL "ial. The density of the sediments within the relict channel are shown by the Standard Penetration Tests (SPT) in Figures 6.9 and 6.10. As noted in Figure 6.9, all SPT for units below C are in excess of 60 per foot 9 indicating a relatively dense compact material. This is supported by field observations which show that the majority of units exposed on bank cuts are, for the most part, free standing. As stated in Section 6.7, only localized permafrost exists within the relict channel. Although only preliminary data is avail able, the permeability of the upper units appear to be rel ative~y low (lo-3 to 1o-5 em/sec) (Section 6 ... 6~. Work performed during 1982 failed to show any continuous uni- form unconsolidated material in the relict channel. In conclusion, altho:.~gh work performed to date does not fully eliminate the potential for static failure within the relict chan- nel, the 1 ikel ihood of such a catastrophic event occurring appears to be small considering: (a) the materials within the channel are relatively competent; (b) no widespread permafrost; and (c) low surface gradients. An alternative method for rim fail Ut"e may be caused by dynamic shaking by an earthquake resulting in liquefaction of the channel sediments. Liquefaction generally occurs in loose, unconsolida- ted, well sorted, saturated materials. Earthquake shaking results in the decrease of the shearing resistance of a cohesionless soil and is associated with a sudden, but temporary increase of the pore fluid pressure. The 1 iquefied material is then temporarily transformed into a fluid mass that could settle and/or flow. To initiate a major 1 iquefaction failure within the Watana Relict Channel, requires the existence of a relatively continuous 1 ique ... fiable material throughout the area. 6-14 I I I I I I I I I I I I I I I I I I I I I -I I I I I I I I I I I I I I I I I Although a few sorted sands and silts occur in various units such as Unit D, 0', E/F, H, and J' (Figure 6.8), these materials occur only as discontinuous lenses. In addition, the high SPT (Figures 6.9 and 6.10) indicate that the materi~l below Unit C are rela- tively dense compact material • Unit C has the majority of the blow counts below 20 per foot. This unit, however, is not a critical unit to the reservoir rim stability as it is relatively freely drained on the surface and makes up only a portion of the rim. Results of work performed in 1982 show that there are no 1 arge scale liquefiable materials in the upper 250 feet of the relict channel. However, ·additional drilling and testing w·ill be requir·- ed during FY83 to further characterize the units at depth anr provide further evidence against the potential for liquefaction. (c) Leakage Potential During the 1982 summer dr111 ing program six falling head perme- ability tests were performed in cased boreholes. Four of these were in Units E/F, one in~ Unit G', and one in Unit I. The calcu- lated results, utilizing standard open-casing falling head calcu- 1 at ions gave permeability between lxio-3 and 5xio-4 em/sec (Table 6.3). These tests were performed in those portions of the borehole which appeared to have very coarse gradations, or where dri 11 fluid was lost. Therefore these results r·epresent the high permeability·range within these units. For the purposes of estimating the maximum probable flow which could leak out of the reservoir undef full head, the following assumptions were made, all of which represent worst possible cases. -That a continuous flow path exists from inlet to outlet on each unit; -That units are not blocked or occluded at inlet or outlet; -That the average gradient is 9 percent (Elevation 2200 pool to Elevation 1675 at Tsusena Creek, over minimum flow path of about 6, 000 feet); -That the in1~t section can provide all the flow that the criti- cal "weir" section (alc!1g seismic line OM-A, Reference 1, Figure 6.34) can pass; and · -That average permeability over the entire cross section is Io-3 em/sec. Under these assurnpt ions, for the known channel width of about 14,000 feet and average depth of 200 feet, the loss at full pool would be about 9 cfs. To significantly affect project power· economics the permeability, on the average, would have to be about lo-2 em/sec. Therefor·e, unless one or more of the permeable units (such as H, J•, K) are found in subsequent drilling to 6-15 extend continuously, in significant cross sections, and are ex- posed to the reservoir, the chance of flows exceeding 10 cfs is highly unlikely. This amount is not considered significant to. project operation. (d) Potential for Failure by Piping Major leakage through the relict channel could result in p1p1ng along Tsusena Creek that would cause erosion and progressive fail- ure working back up the channel. Although the geologic model to date does not indicate piping to be a problem, further geotechni- cal studies plan ned for the winter of 1983 ar~ intended to deter- mine permeabilities of the lower stratigraphic units in the relict channel. If, subsequent to this program, piping is considered a potential problem, then discharge points along Tsusend Creek will likely be controlled by the placement of properly graded materials to form a filter blanket over the zones of emergence. 6-16 I I I~ I I I I I I I I I I I I I I I I -.. ---------------- TABLE 6.1 (Cont'd) STRATIGRAPHIC UNIT BORING NUMBER A/8 £ M 0 0' E/F G G'-H I J' J K BEUl!:?DCK - AH-013 0 0 .. 6 15 20 >SO AH-D14 0 0 .. 5 14 >75 AH-D15 0 2.5 34.5 72 >84 AH-D16 0 3 29 43.5 58.5 67 111.5 147 156 17u .. -5 AH-D17 0 2 40 76 90 103 107 184 187 207 2'15- AH-018 0 3.5 25 1•6 97.5 131 )189.3 • AH-019 0 6 15 70 166.5 194 >215 AH-D20 0 3 24 65 105 114 13& AH-D21 0 3 18 63.5 101 108 115 137 ·n~ AH-022 0 6 AH-023 0 5 ... 2 26 38.5 92.5 >160 AH-D24 0 4 30' AH-D25 10 7 28 71 >90 AH-D26 0 4.2 15.5 75 83.3 96- AH-027 0 5 20 59.5 63 157 177.5 >195 AH-028 0 3 19 98 123 196.5 210.5 >234 AH-029 0 4 14 18 149 >158 AH-D30 0 6 18 69.5 >100 Notes: (1) Stratigraphic column shown on Figure 6.2 LEGEND: 6 Depth to unit from ground surface (2) Top of Unit Maps on Figure 6.6 Boring passed through stratigraphic sequence ( 3} Unit thicknesses shown in Table 6.2 without detecting indicated unit. · (4) All borings vertical, numbers shown )69.5 Bor · .,g terminated in previous unit -dept.h shown (5) are true depths. rep1~sents minimum possible depth of next Due to lack of samples .and core photos, unit contar.t at that location pre-1982 hole interpretations are less (blank) Boring did not penet.:at.;:;, or could not be certain than for AH-D15 through AH-030. sampled at depth necessary to detect presence of unit • --------- - ----.. -- ---------------------- TABLE 6.2: WATANA RELICT CHANNEL/BORROW SITE D INTERPRETED STRATIGRAPHIC UNIT THICKNESS IN BORINGS STRATIGRAPHIC UNIT BORING BEDP.J::K NUMBER A/8 c M D 0' E/F G G' H I J' J K ENCOU~-ERED OR-13 Not noted 15 63 6+ No OR-14 " 20 55+ No OR-15 II 15 7 14 19 231 Yes DR-16 II 31 16 20 Yes OR-17 Not interpreted DR-18 II 20 68 22 60 61 Yes OR-19 Not noted 36 19 Yes DR-20 II 20.5 32.5 37 77 43 Yes DR-22 II 56 34 41 52 48 62 161 Yes OR-26 11 19 26 11 1'1 27 .8+ No, OR-27 " 2'1 23+ No {) AH-01 4.5 15.5+ No AH-02 0.5 2.5 26+ No AH-03 Not interpreted No DH-04 II No AH-05 '1. 5 6 2.5 38.3+ No AH-06 5 2.5 14.5 28+ No AH-07 .5 14.5 33.3+ No AH~OB 4.5 l) 5.5 35.3+ No AH-09 '1.5 3 1. 5 34 10 2 6 6 Yes AH-010 1.5 6 42.5+ No TABLE 6 • .2 (Cont'd) STRATIGRAPHIC UNIT BORING NUMBER A/B c M 0 0' E/F G G' H I J' J K BE~:JCK --- AH-011 3 11 5 29.8+ No " AH-012 4 56+ No AH-013 .6 14.4 5 30+ No AH-014 .5 13.5 61+ No AH-D15 2.5 32 37.5 12+ No AH-D16 3 26 14.5 15 8.5 44.5 35.5 9 14.5 Yes AH-017 .2 38 36 14 13 4 77 3 20 8 Ye;.~ AH-018 3.5 21.5 21 51.5 33.5 58.3+ No AH-019 6 9 55 96.5 27.5 19+ No AH-020 3 21 41 40 9 22 Yes AH-021 3 15 45.5 37.5 7 7 22 37 Ye<3 AH-022 6 Yes AH-023 5.2 20.8 12.5 54 67.5+ No AH-024 4 26 Yes AH-D25 7 .21 43 19+ No AH-026 4 • .2 11.3 59.5 8.3 12.7 Yes AH-027 5 15 39.5 3.5 94 20.5 17 •. 5+ No AH-028 3 16 79 25 73.5 14 23.5+ No AH-D2j 4 10 4 131 9+ No AH-D30 6 12 51.5 JOo5+ No Notes: ( 1) Stratigr-aphic column shown on Figur-e 6.2 LEGEND: 6 Thickness of unit where encountered in boring (2) Borrow material isopach maps shown on Figure 8.2 Boring passed throu.gh stratigraphic sequenee (3) All borings vertical, numbers shown are without detecting indicated unit. are vertical thickness. 30.5+ Boring terminated in unit; thickness shown (4) Due ~o lack of samples and core photos for represents par-tial thickness. comparison, pre-1982 hole interpretations (blank) Boring did not penetrate or-could not be are less cer-tain than for AH-015 thru AH-030. sampled at depth necessary to detect presence of unit. --------.. -------- -----------~---~--- Test Type Depth (ft) Stratigraphic Unit Intake Point Average Permeability Range of Permeability (em/sec) Duration of test Reference (32) TABLE 6.3: WATANA RELICT CHANNEL/BORROW SITE D BOREHOLE PERMEABILITY TEST RESULTS HOLE NUMBER AH-D18 AH-D18 AH-D20 AH-D21 Fa 11 i ng Falling Falling Falling Head Head Head Head 91.7 144.0 122.5 54.0 E/F G' I F HW Casing HW Casing HW Casing HW Casing Flush w/ Flush w/ Flush w/ F1 ush w/ Bottom of Bottom of Bottom of Bottom of Hole Hole Hole Hole -4 -3 -4 -3 5x10 2xl0 2xl0 2x10 -5 -4 -5 -4 4.5x10 2.5x10 4. 3xl0 1.3x10 to -3 to -4 to -5 to -2 5.3xl0 2. 8x10 5.7x10 1.9x10 2 hrs 2 hrs 2 hrs 2 hrs AH-023 AH-027 Falling Falling Head Head 38.8 140.0-145.0 E F HW Casing 5 ft Flush w/ Section, Bottom of NX Core Hole Hole -3 -3 lx10 4x10 -4 6.6x10 0 to -3 to -3 1.7xl0 1.2xl0 1-1/2 hrs 1 hr WATANA BORROW SITE D/RELICT CHANNEL SURFICIAL GEOLOGIC MAP SHEETI OF 2 SCALE FIGURE 6.1 I I I I I I I I I I I I I I I I I I I WATANA BORROW SITE D/RELICT CHANNEL SURFICIAL GEOLOGIC MAP SHEE"!" 2 OF 2 LEGEND: SURFICIAL DEPOSITS -ICE DISINTEGRATION DEPOSITS BASAL TILL OUTWASH BASAL TILL -EARLY OUTWASH 8 BEDROCK 0 DR-17 0 AH-021 A A u 0 NOTES: BOREHOLE,COE BOREHOLE,AAI CROSS SECTION LOCATION FOR CROSS SECTIONS SEE FIGURE 6.4. 2 MAPPING BASED ON AIR PHOTO INTEHPRETATlON, RECONNAISSANCE LEVEL GEOLOGIC MAPPING, AND LIMITED SUBSURFACE EXPLORATION AND IS s ... BJECT TO VERIFICATION SCALE FIGURE 6.1 I I I I I I I I I I I I I I I I I I UNiT TYPE OF DEPOSIT GEOLOGIC EVENT ~-8~/~B~4_s_u_R_F_~_~_L_~_P_o_s_rr_s+_P_OO_T_G_L_~_I_A_L_E_R_o_ffi_o_N_a_F_R_os_T_H_~_v_r_NG_. ______ ~~~-~0:·~--~~0~.··~:._•_•~~·~:8~./~B~j~~~·=~i~·:~·6~.~~~\~.~~·~~~R-~-~-:_._~_~:=~~~a~~~m~~·~R~~~~~~~~a~ " .~1--_ . .--... __ . .. .. ,....., __ .... ---~ TAN-BROWN SAND WITH SOME COBBLES a 1·. HUM.MOCKY TOPOGRAPHY. KNOB a KETTLE ABLATION OF LAST GLACIAL ADVANCE a MELTING OF ICE· .__,. 1,.'\ '-" Q RANGE 0-38FT. til • © ICE DISINTEGRATION 1· .. Q · .. !''1~~ .. · · .. C:l . ::::... •. A 9 FT. GRAVEL. LOOSE TO DENSE~ CONTAh S LESS l FEATURES, NO OVERCONSOLIDATION. LENSES. r-.. . -:..Q= · · .._. · VG. · SILT THAN OUTWASH UNITS E a F: i . MAJOR GLACIAL ADVANCE----.~ ·O .. 0 '" . -·•· ~ · . . 1 UPPER LIMIT OF OVERCONSOLIDATION---t .,INTERGLACIAL, ICE. FRONT A LONG DISTANCE. F. ·R. OM AI.:....~.} . .:-o __:\(:::~~f.~···-~-' R. ANGE. ·. GRAYS I RATIFIED SAND, GRAVEL a COBBLES, l CONFINED TO TOPOGRAPHIC LOW AREAS ON ALLUVIUM __ ~OSITIONALA~---__ --~·~-_//1·:0. t{)-=o~~~;;·o 0 _: \''~~~~.··· ~ERY ~E·_ ... .,, .. , .---_ j TOP~NIT"E"aR~EDFLOW~NNE~ j L~~ o . GRAY/BROWN LAMINATt:o CLAY a stLT, 1 LIMITED EXTENT, NOT FOUND IN ALL LACUSTRINE LOCALIZED POODING OF~ DURING lli.!§..RGLACIAL. "' -~ .... O~--· ·~@.-O· --9 -.· \ O~~~~~. VERY DENSE ~ ~~~~GS. LAMINATIONS PRESENT.GENERAI..LY BASAL TILL I VALLEY TYPE GLACIAL ADVANCE CONFINED TO FORMER i :-0--. -0--.· . o .. \ \ RANGE FRACTION MAINLY PHYLLITE a ARGILLITE. ! A?PEARANCE SIMILAR TO "G" BUT MUCH @ ~-- RETREAT oF GLACIATION "M"~-~" l'f---· O ~· a 0 · ·---· 'G9AYCL.',4y~wm-t ANGULAR TO sUBANGULAR ! FOUND NEAR susiTNA VALLEY. PEBBLES a r.: ... = ~ -0-· ·-·0-.. -.0· i\ GRAVEL !i COBBLE, V';:RY DENSE. COARSE j (X)BBLES SUBANGUU'C:: a STRIATED. I sus1TNA VALLEY. , j '~ 0 C?-. . .. ·C?· .c;,.·.. ., \ 0-79 ::r. j rttGHER PERCENTAGE OF PHYLLITE a 1:-----!--------11~-. -------w "- 0 -u::-tO~·.:-~----~~ o~ · -~":r I \\ L___..--~ BROWN To GRAY-BRovm SILTY sAND WITH ; :::~~:~::~~~~;:~uNoED PARTICLES. @ OUTWASH GLACIAL MELTING a 11ETREAT; JCE FRONT AT A DISTANCE : ~~::<: . . a· ~. :: ·{~: l \ GRAVEL a COBBLES. l FEWER COBBLES a BOULDERS THAN UNIT _____ -4 ~ROM ~ITE. _____ --____ :,7 .. · .. ·· <: ·:6 ·. ·.~· · .. ~ .·_.'--:--{ i.·· \___ __ --·~ARTICL~.SUBANGULA_R}OSUB~E~ i:F"BELOW._!'ARTIALLYSORTED_. ___ _ • 0 ...---:.._. • · ( "'\ • ··o· 0 RANG.E E/F. BROWN SILTY SAND WITH GRAVEL. a MANY l LARGE COBBLES a BOULDERS INDICATES . 0 ; ; .--.. ®: \...___.;_ ... f .. ; J COBBLES a BOULDER$, POORLY SORTED. i HIGH ENERGY ENV!RONMENT WITH ICE ,,.. ,_... · v O-l3 l FT. SIZE OF COARSE FRACTION INCREASES WITH l FRONT NEARBY. LARGE BOULDER ZONE AT r---- ® OUTWASH · GLACIAL RETREAT; ICE FRONT NEAR SITE· I · 0 . 0 --c · Do: . 0 ' • ;..-:..-.:?· l AVG. 37FT. DEPTH. OFTEN CONTAINS A ZONE OF • BASE GRADING TO SfhALLER FRAGMENTS ! ~ .··'"'\ ~ D, • •.. .. -. · : \' l COBEILES a BOULDERS AT BASE OF UNIT. ! TOWARD THE TOP OF UNIT INDICATES ~---t----·---+ .. __ ····-_ f DRAINING OF LAKE "a" 1 ~ ... -._) 0 L': · · 0 .•.. · . b.~ ... J _ . I RECEDING ICE. ! L GLACIAL RETREAT BEGINS J ~~··,···.· -. ·:··,_ ... · · ... · -.!l._ •.. ' ~~~~A~~~ysi~I~:~~Nci;RY DENSE. l ~~:G~g~ ~g~~~ :~ ~~~~A~~~io~ ~~T ® - ® RANGE INTERLAMINATIONS WHICH ARE MORE ! tiN IT "G". GLACIOLACUSTRINE _LAKES a FLOATING teE. lCE MAss PARTIALLY DETACHED ® I L NT H L ~ n ---- --/ • ---·• • ·' o 74FT. PREVA E IN RELICT C . ANNE AREA. S WATERLAIN TILL (FLOATING). ~= = = = =;.~-o ~ -_·:__ .. , ~ ' OCCASIONALLY VARVED. LACUSTRINE LAMINATIONS &VARVES r-'" -- BASAL TILL ALLUVIUM I +--~ ... •e l ·-· BASAL MELTING, ICE THICKENING MAJOR GLACIAL ADVANCE. i--- ---J ·.<I . <; --PP.ESENT TOGETHER WITH STRIATED '· - ----;' 0 .. ~· ." o ·. : .· . .' ': i PEBBLES a SAND AS WELL. ----. 1 = -=--=--=----/;.'):< ®. o .. t>._ · _ .. · ·-r--1 G"'AYCLAYWJTH ANGU-LAR a - -r--sr-RIATIONSON coARsE FRACTION. LITTLE '-, I=--:_---_--:_; : .. ':, 0 . ~ ·-: / RANGE l"UBAMGULAR GRAVEL a COBBLES. OXIIli>TIOM, BASAL TILL STRUCTURE "-. '(-----.c. · ·. .(; · 0 ~: • / 0~231 FT. UNSORTED• VERY DENSE. INcLUDING POOR SORTING, HIGH DENSITY a f-----i -;-.,· \> o • . \7. .o __ . ----... ----IMBRICATION OF ELONGATED FRAGMENTS . . /'';-. ·. ···-~-· · · ·' . . · . "" ! B[ !OWN GRAVEL, SAND f.l SILT, STRATIFIID, 4 ROUNDED PARTICLES, SORTED. ORGANICS I / ; 9· ·. -.. ~ ·. : k-;@2%/. (~·! ""' ~ANGE I SORTED, VERY D.ENS.E CON. FINE.· 0 TO.. i' FOUND IN UNIT "H". !INTERGLACIAL, ICE FRONT REMovEo FRoM sm::. . ~ : : ._. · '-·. . , ~-. , · . · 1 ...._ 0 41 FT. 1 vALLEY AREAS tN THE AT-THE-TIME ! I ; '""': ·. . . . -', . \-: . . , j TOPO;iRAPHY OF THE UPPER SURFACE OF , l ; ... C . :J. 0··~·~.5: ,. c:li IUNIT"I". r: 1-~--+--------~!------------·· .. -· ... -~--.. ~ ... -().~ · c>-'""' :. ·c,·~·:.: --~ · ··: !BROWN ro-RED-BROWN •• SAND a SILT VrtTH [ORGANICS FOUND IN~UPPER HORIZON oF ·I . . · '"'_· '(j) '· · · · · ;"' GRAVEL a COBBLES. '))\I OAT ION ON ! UNIT "I", INCLUDING WOOD. (j) OUTWASH lTILL?) · .6._ · ·=~ . . "(:;i· .) . ' . :-' ·~ i SURFACES OF PARTICL~S. VERY ROCKY, I GLACIAL MELTING a RETREAT, ICE FRONT NEARBY . ,:).._ · 'OVERCONSOLIDATEO Mll.Y BEAN OUTWASH OXIDATION (LIMONITE a HEMATITE) t PARAGLACIAL ENVIRONMENT ; <J ."} ~ V' 0 l> : .• 4 :0. ~ : RANGE R~'-'.,ORKED BY A MINOR HEADVANCE. INDICATES WEATHERING a OLDER AGE. MINOR GLACIAL RE-ADVANCE. ~ • '-· ';' . _::,.. ·. ~··.q I 0-77 FT. OF l<.t.. . OCCASIONALLY DISPLAYS SOME ' . CHARACTERISTICS OF A TILL INCLUDING I ~~..,_,. REMNANT STRIATIONS ON PEBBLES 8 i GLACIAL MELTING !i RETREAT CONTINUE$. ~~~"1:'. ANGULAR FRAGMENTS LACUSTRINE SAND, I . ; :(:)o ... ~ .... ~\: .. .::::> <> o·oo_o o .. '7\a SILT OR CLAY QFTEN FOUND IN MIDDLE OF -... -~. -· --I 0 • •. a'-o ,:__') 0. ~ ·D c:::) ~"a ~-~ UNIT. ·~· ···--~----i l BASAL MELTING f\ 'NDING·, FLOWING WATER. ., ."' o. . . . o .. ~ . ~. ...._ O 48 Ft LAMINATED a /OR STRATIFIED. SAND ; FRAGMENTS RCUNDEO --jr' ~ [OF GLACIATION "J"~-.. /'1 o ~ ~:;l'~.A~: .-~6 o ·'-. RANGE BROWN SAND, SILT, GRAVEL a CLAY, 2 LIMITED EXTENT, CFTEN APPEARS SORTED, , I ":': !> "' ..!). >0 :: , . " :;:::;;-.,: . ? -~ . OCCASIO~ALLY OXJOJ.Zf£D. l . I ---+------~-+--------.,___ ·· ___ ,. ! :· .o , 0 ~::-. · Qj:~~: o ·~0,·. ·,:~ · · {, RANGE ··~ BROWN stLT WITH MANtcoBBLEs B MucH t sTRIATED PEBBuis,sua·ANGULAR j MAJOR GL~ ADVANCE. , i , .. ~:. ·0 0 ., :. :. · , . l> () ~ O-62 FT. GRAVEL. VERY DENSE:, OXIDIZED. PARTICLES i PARnCLES, HIGH DEGREE OF l 1 o · o. • . . . t>: .Q ·. t> • o · . o . ,, ANGULAR a suBANGUL.AR. 1 ovERCONSOLIOATION~, ""= · ~---+-------~~~-0-E-~~U-N~C-~-S~O-L~ID~A~T=E~D~D=E~ro-S~IT~S~ro~U~N~D~~~M /1 ··-··--~ '~~' R~GE OOU~ERS.~OOLB,M~&GR~a. 1rou~~~W~L~AW~~AAN~L • RELICT CHANNEL AREA. I " x '· -~" :: ' ~ ~ J.; · \ 1 "-.?~~s.~~.E:~ ROUNDED. .-.. ~-f couRs~!!~~~-~~!.l Clff INT~ROCK. I. NOTE: STRATIGRAPHIC COWMN DIAGRAMMATIC a NOT TO SCALE. ; \. ."":. "-....._ .\ \ \. ·' . PRIMARILY DIORITE 8. GRANODIORITE l DRILLED> 10' H.;TO BEDROCK TO VERIFY. Jl " \'@. \ \ \ \ )I WITH OCCASIONAL INCLUSIONS OF ' \ \ \' \ -\ , ARGILLITE. ANDESITE FOUND IN WESTERN I J .\ . \ . ' l PORTION OF AREA. l GENERALIZED STRATIGRAPHIC COLUMN W~f"ANA RELICT CHANNEL AND BORROW SITED AREA FIGURE 6.2 I, I I I I "I I I I I I I I I I I I I I r-----~------------~----------------~----------------~--------~-------------------------------------------------------------------------·-----· ------------------------~------------~ ~ WATANA BORROW SITE D I RELICT CHANNEL STRATIGRAPHIC PANEL DIAGRAM SHEET I OF2 NOTES: '.1. FOR DETAILED STRATIGRAPHY SEE FlG".lRE 6.2. 2. FOR LEGEND SEE SHEET 2,. 3. EXTENT OF STRATA AND CONTACTS ARE Llij=fRRED SA..~ ON lNTl::RPRETATION OF SUBSURFACE EX?t.ORATIONS ANrJ. ARE SUE!cJECT TO VERIFICATION BY FUTURE INVESTIGATIONS APF'ROX!MAtE SCALES o 4oo . . aoo FE:ET HORIZ.l:!!.. ~"··~ ~ ==:z VERT. ~ .. • .. ?"!?· 1?0 FEET t f J APR~lj ------------------~--------~--------~--~----------------~--~~----------~--~~--------~--------------~_Fl_GU_R_E __ 6.3~~'="~Ui=.··=·~fj .. WATANA BORROW SITE D I RELiCT CHANNEL STRATIGRAPHIC PANEL DIAGRAM SHEET 20F 2 LEGEND: ! AIB;,j SURFICIAL DEPOSITS f;;;jc,({..;,j .ICE DESINTIGRATION OEPOS!TS ~"-;M:"'£1 BIISAL TILL I 0: :j ALLUVIUM E:;::o•® LACUSTRINE ~OUTWASH 83 LACUSTRINE ['f~"'hf BASAL TILL t•.".H:: •• j ALLUVIUM ~OUTWASH r.j ,!_' l~J ALLUVIUM/LAC'USTRINE f,;.J5j TILL ~ALLUVIUM ! Br ! BEDROCK NOTES• !. FOR DETAILED STRATIGRAPHY SEE FtG~5t't (; 2. 2. EXTENT OF STRATA AND CONTACTS ARE !No'i'~~REO BASEO :N INTERPRETATION OF SUBSURFACE ElCPL<:'R~TrvNS AND A.'\E: SUBJECT TO VERIFICATIOI>! SY FUTURE lN\;.'STIGATlONS. APPROXIMATE SCALES 0 400 cC" FEET HORIZ.C2 ' 0·~~-.~~;;-:::::::-JQi;·~IOP FEET VERT ._ , __ __ FIGURE 6.5 I 2300 I 2250 2200 I 2150 I 6r 2050 I ;::' w w LL :z 2000 0 I ~ > w ..1 w I Br-SL I SECTION A-A I ,, 0 I 23oo r SL80-7 I 22!50 22.00 I I 2150 ~ E 2100 F G ;: ffi 20!50 I LL :z Q i=· ~· 2000 UJ I iii 19!50 l I 1900 1850 I I I 2250 2200 2J50 2100 Br 2050 :z 0 ;::; ~1900 11.11 ...1 11.11 1800~ I 1100 L SECTION C-C WATANA RELICT CHANNEL CROSS SECTIONS SHEET I OF 3 SECTION 8-B SLS2-IS Br ., LEGENq ftNl.Bai SURFICIAL DEPOSIT fM;:;::a ICE OISINTEi'lGRATit\N OEPv'SITS ~ BASALTILL ~ ALLUVIUM ·~ O!.lTWASH E:G"-3 LACUSTRINE fiG'~j BASAL TILL {•;;H~vi ALLUVIUM ~ OUTWA~ f;.J•,:-j TILL "" .., G:Zfl 4U.UVlUM ANO LACUSTR~H£ OEPOS;:;-s mE ALLUVIUM I Br J ae:onocK NOTES: SLS0-1 G' ~r-SL L FOR OETAll.S OF STRATIGRAPHY SEE FIGU~i:' "ti.2. 2. !"OR LOCAT10N OF SE;CTIONS 5m FIGURE ~ t 3. EXTENT OF S'tftATA ANO CONTACTS ARE 1.!\iiF£!\ilEO BASEP ON lNTERPR£"rAliON OF SUBSURFACE ~TIONS AND ARE SUBJECT TO VERIACATION BY fllTURf. il'S\'ESTIGATIONS 0 400 a 0 FEET JlORlZ. SCALE t.~·-·•« < 0 50 100 FEET VERT. SCALE IL.-=' ::21 FIGURE. 6.4 I I I I I I I I I I I I I I I I I 24!50 2400 2350 2300 2250 2200 ~ 2150 !e :.<: 0 ~ 2100 ~ ..J w 2050 -:!uOO 1950 1900 1850 AH-029 !e.. o "0 .._____ 800 ----"' I GOO 2400 --:: ---,~~ .. _____ _ __ --7 3200 -~~----------.~~~====~~~~~::~.~s;~4oo 5600 4BOO !STANCE [FEI:Tl 4000 HORiZONTAL J 7200 SECT!Of!__Q:Q WATANA BORROW S!TE D CROSS SECTION SHEET 2 OF 3 8000 8800 11200 51-SURFICIAL DEPO t t§/EJ a•:noN ICE OISINTEGrvo [1£%3 ~ BASALTILL ~ AlLUVIUM ~ LACUSTRINE ~ OUTWASH [fil .LACUSTRINE EG:-:J. f;G;Eij BASAL ~LL ~ AlLUVlUM ~ OUTWASH rr-.-;-~~ TILL ~ (!f.] BEDROCK NOTES: DEPOSITS RAPHY SEE FIGUR~ :;:;:. . ~ . OF STRATIG , FOR DeTAILS . SEE FIGURE 6 • OF SECTIONS ,~~En BASe: FOR I..OCA~ON . CONTACTS ARE ~~~<JNS ANO > XTEIIT Of STR~ ~~DSUBSUR~fur"f.\f ~TlONS. 3 • 5N lNTERP_RET1if VERiFICA~ON B ARE SUBJECT HORIZ. SCALE VERT. SCALE FIGURE 6.4 I I I I I I I I I I I I I .I I 2350 OR•l4 Gi Ul u.. 2.300 22.50 22.00 z 2.150 0 ~ Gi ;::12.100 2050 2.000 1950 ''390 2350 2.'30C 2250 2200 ... l::J2150 ~ z 0 ~2100 > 1J.! .J w 2050 0 2000 1950 1900 0 BOO 800 1600 2400 3200 4000 HORIZONTAL DISTANCE (FEET) SECTION E-E 1600 ~400 '32.00 ~000 HORIZONTAL DISTANCE (FEET) SECTION F-F 4a00 51300 4600 5600 WATANA BORROW SITE D CROSS SECTIONS SHEET 3 OF 3 6400 noo 0' 13400 ----------~,.~----~----------------------------------------------------------------------------------------~-·~~---------------------------------~~--------- LEGEND: bl\;a{~ SURFICIAL DEPOSIT ~ . ICE. DISINTEGRATION DEPOSITS ~ BASAL TILL CTI ALLUVIUI,\ ~ -LACUSTRINE l~JJ OUTWASH EE l,..ACU:.. .lNE t;-=~hl BASAL TILL ~ ALLUVlUM ~ OUTWASH ~ TILL CEJ BEDROCK I. FOR DETilJLS OF STR~riGRAPHY SEE FIGURE ;(S :;:. 2 FOR LOCATION OF SECTIONS SEE FIGURE$,;. '3, EXTENT OF STRATA AND CONTACTS ARE IK'-"~~RE~ SAS~O ON INTERPRETATION OF SUI}SIJRFACE EXPLC:Jltl!cTH.'!MS ~ti(J AoE SUBJECT TO VERIFICATION BY FUTURf: ~\~V.~TIONS . 0~~~450~0-~8~{0 FEET HORIZ. SCALE p ::= - o M too n:n VERT. SCALE E 72 I I I I I I I I I I I I I I I I I I I I I UNIT C UNITM ~ '. I -·'--~ ... "'.:· ~ ~ .- ' -/"'¢-·.:-~ ,;'tt -~;:.·: •), •·. ~ _'i, • ~;<.·~'::/~. ~:fi:, ... • W*v-. //t.'\:.it-~-~ .... •"' (( :~r· ' "lj'' -~ ~ ... :~ Y!ATANA RELICT CHANNEL/BORROW SiTED TYPICAL MATERIAL PHOTOS SHEET I OF 7 ·FlGURE 6.5 I '- I I I I I I I I I I I I I I I I I I • I -, .... -·-----"------w· ----~-~-"-'" -..:...._._ ~ !, ~ -. ' • -~~ ' ..... ' UNIT D UNIT o' WATANA RE~ICT C~ANNEL/BORROW SITE D TYPICAL ~1ATERIAL PHOTOS SHEET 20F 7 I FIGURE 6.5 I I I I I I I I I I I i I I I I I I I 0 ' : ~ ' ,, . ':..\ J 11\JIT J:' 1 r: '-"1--w1 t -T I -} 1 UNITG WATANA RELICT CHANNEL/BORROW SITE D TYPICAL MATERIAL PHOTOS SHEET 30F 1 FIGURE 6.5 I I I I I I I a I I I I I I I. I I I I ll l! fi I I i I ( l' ,__;;. '·~;, ' UNIT I WATANA RELICT CHANNEL/BORROW SITED TYPICAL MATERIAL PHOTOS SHEET 40F 7 FIGURE 6.5 I I I I I I .I I I I I I I I I I I I I UNIT F UNIT G' WATANA RELICT CHANNEL/BORROW SITED TYPICAL MATERIAL PHOTOS SHEET 5 OF 7 FIGURE 6.5 I I I I I I I I I I I I I I I I I I I UNIT D UNITE \1\'.~TANA RELICT CHANNEL/BORROW SITED TYPICAL MATERIAL PHJTOS SHEET 60F 7 FIGURE 6.5 I I "I I I I I I I I I I I I I I I I I '- L. __ UNIT H / WATANA RELICT CHANNEL/ BORROW SITE D TYPICAL MATERIAL PHOTOS SHEET 70F 7 FIGURE 6.5 I I c 0 o: ~ r;; ~~ (';j, t;: ~· ..;! \ ~; tt~ '" "' 'trii tli rr> !;'>-o "' \'>. ... ~' u~ !lJ !:3,;! ,..,..,_,.., I I I I I I I I I I I I I I w • > WATANA BORROW SITE D/REUCT CHANNEL ;.....we:c-\"ll """2120 TOP OF STRATIGRAPHIC UNIT E/F CONTOURS SHEET I OF 3 •,J!~~ ~"'-~.14 .~ .'\t.1 ,;~~~tr •"·"", · •. ·~ ' .-.. ·:=--~~~·~ .... ·~ ~.# ..... ._~ ffJVt!J? \ ."" \... ,#'i l-' SCALE 0 e LOCATION MAP LEGEND: •DR·2C 2.172 TOP OF STRATIGRAPHIC UNIT CON'roURS. BOREHOLE (KNOWN DATA POINT) ELEVATION OF TOP OF UNIT AS SUuWN. ® WSZ-61 SOIL EXPOSURE ( I<N0\1'N DATA f'QtN'f) 2120 APPROXIMATE ELEVATION OF TOP. OF UNIT AS S!:'i~ C> 1000 2000 (FEET) SCAt,E L .. -5 . Y? FIGURE 6.6 I '1 I . . . . ~. 1AISI I I I e;• c ~i~ 0 t;'; Q q C!-. r; i..l 'J ::r; 1i~ '" l'• ~"-~· I I 1.).) Ul :,~-~ I I I ""'. ,,, I I I ' ~-__ .,, ~¥ r-, ""• • "'> _ .... :..., .. ,- I I I I I I I I w ;,,.:::; ,. -~-~ "' ~ t':'<l '"• ~ ·-· s ~ -·-, -..\.>' 1,"]' ~.1 t ... _ "'· r-. ~ ii..'.:# w w .. 'NATANA BORROW SITE D I RELICT CHANNEL TOP OF STRATIGRAPHIC UNIT G CONTOURS SHEET 2 OF 3 :t\~-GJ ~ rt~t/fA~~ .·cr: ··-· ·-"""'"""'~->'; .,. ~ 't .- 0 4 8 MILES: SCALE I""* . Ji:ili '777 LOCATION MAP LEGEND: ---- &DR•20 -2187 TOF Of' STRATIGRAPHIC UNIT CONWURS. BOREHOLE (KNOWN DATA POINT) ELEVATION OF TOP Cf UNIT AS SHOWN. ® Wn2·~2 SOIL EXPOSURE (KNOWN DAiA PC!INT} 22.!0 APPRCXIMATE ELEVATION OF TOP '{IF UNIT AS SB':l\\li 0 1000 2.000 (FEET) SCf:.LE. ~a ..iJ FIGURE 6.6 I I I I I I I I I I I I I II • I I I I I 0' §~ 0 g 8' a 0 m !j) '¢' t'J lt~ 4~ !!;')' "" I'-. .... "'" e~: :W u L:! ",,.~,_,.,_.,, ,.,-·-~> ' l 8 q 0 ,, £>, . lt.1 x n ("> q :~ ~ ;l o:; ~ ~ <•; ~ ,, ""' .. f.. "~ ~ ... ,.,, ~.,J 'o-~;; ''"~""""" ~>, WATANA BORROW SITE D/RELICT CHANNEL TOP OF STRAriGRAPHIC UNIT I CONTOURS· SHEET 3 OF .:; ·~;·_:;'::t,':--,~~JA ~·,t\~Vl :;'':$..>'"'"'" ..,.....,,...·- SCALE LOC'ATION MAP ; /./ LEGEND: • DR-19 Zl51 1':h W82·91 'OIJ890 TOP OF STRATIGRAPHIC vNIT CONTOOOS • BOREHOLE {KNOWN DATA POINT) ELEVATION OF TOP OF liN!T AS SHOWN. SOIL EXPOSURE (KNOWN DATA POINT) · APPROXIMATE aEVATION OF' TUP OF UNIT AS ~'DWN 0 1000 2000 (fEET) SCALE en!. . .. _,. ] FIGURE 6.6 I I I I I I I I I I I I I I I I I ., r, L.$ -.. ~-"' .:. ,,·;. _;-l ~- WATANA RELICT CHAN . . . .. TOP OF B~~~6~~RROW SITE D I~ \.tl\ii"t'i'J/\ L:H.~ ,...-,.\~ ... ,." ,. _.,..,.,,·-· . ~· -._-: ~ ''._,.) ' ' ,./ C' ··"' ~ . ""'"-~. ~~·!1>·Zi7!.: ... ~ * ~-· 0 4 LOCATION MAP SCALE ~L.-~--~~5--~8 MILES ______ :.....:::::_ ____ ~ ~-iii LITHOLOGY: CJ BEDROCK OUTCROP CONTACT: • UNDIFFE:REN1":ATED. BEDROCK /SURFI CONTOUR LIN-S . CIAL DEPOSITS ,...,__....,., t:. : ;.;;t-·rnOXlMATE TOP OF BEDROCK 50 FOOT CONTOU~~ONTOUR INTER\ "A, SO TOPOGRAPHY DASHED --FEET ,CONTOUR INTERVAL CO FEET NOTES: ·~ I I J ! l BASE MAPFR SHEETS 1 TH~J978,COE _1u_ , 2. EXPLORATION GH 26 OF 26~200 OAM$i'TE 1UPOG A:PENOJCES ~ .. ~OSEIS.ICtt ~ RAPH> 3 · Dt:TAtlEO 1UP ~NO AAI ,::2s~:;,i:.;,,t;tls SHOWN:' FIGURE 5 I OF BEDROCK IN • • • ,'II; 4 ' • DAtASITE -r . SUPERCEOES . t;R_ \ SHOWN 0 FIGURE 6."3S N I. • AAI,I9BZ . I FIGURE 6.7 --------6---------v U.S. Standard Sieve OponlnQ!S ln lnchn U.S. Standard Slov~t Nun.btn Hydroml'lfer ·---, 0 ~ tO I 20 ~--·· ' :30 -.&:. -Cll • 3t "" ..0 ~ ~ ., .... 0 0 u -c. lU (,) ,_ e> 0.. 01000 ............ --::~~ ........... =-_L ____ lLLLLl_l_l __ l_ __ _llLLll_L_L__L ____ lUu_Ll_LJL __ L_ __ _uUJJLI:t~~~~~~~~.L_L--L.~-----Q~OO.~ 100 &) [) 5 0.5 Ql 0.05 0.01 0005 500 GRAVEL SAND BOULDERS COBBLES Coarse Fine Coarse Medium Fine f. AH-023 2.. AH-0 19 3. Di<-14 4. AH-023 5. DR-15 SAMPLE 23 -7b SAMPLE 19-7 SAMPLE I SAMPLE 23-3 SAMPLE I 17.0 -19.0 FT. 14.0-16.0 FT. 0-2.0 FT. 8.5-10.5 FT. 0-15 FT. SM sc SM SM SM BULK EXPOSURE SAMPLES 6o. W82-74 6b. W82-'74 7o. W82-2 7b. W82-2 (W /2" MAX. PARTICLE SIZE) PIT I,IA 11B . · PIT l,lA,IB {W/2" MAX.PARTICLE SIZE) WATANA RELICT CHANNEL I BORROW SiTE D TYPICAL GRADATION CURVES STRATIGRAPHIC UNIT C SHEET I OF 10 FINES SHt Sizes GP-GM SM GP-GM SM C\ StiteS FlGtJRE 6 . 8. I ---------... --------~-- U.S. Standard Slave Op.nln1Jt In Indict 12 9 6 3 2. 11/2 I I fl ~ ' 100 90 80 70 -;s;: CJI 4D ~ 60 >. .Q ~ • 50 e . ii: -·c: 40 ~ ~ 0.. 30 0 20 . 10 01000 500 100 50 BOU..DERS COBBLES Coarse I. AH-016 B SAMPLE l6B-29a 2. AH-027 SAMPLE 27-12 3. AH-023 SAMPLE 23-11 4. AH-029 SAMPLE 29-7 5. AH-027 SAMPLE 2.7-10 6. AH-027 SAMPLE 27-5 7. DR ... l5 SAMPLE 2 8. DR-14 SAMPLE 6 U.S. Standard Sl_.e NurM>tra I 3/4 1/2 3/8 4 10 20 40 60 80100 200 210 ~!Ill I I I I I ~ r--.. I--1-o.. """ ~--....~ ~~ -r---1'---............ ..... ~ t!:n ~!;a, ~ [\ ..... ~ ._ ~ ~ ·" :--.... "'r-. r't,......_ ~ .... ~ ~~ ~ ., v' too. _\ N !'-~ "'~ \ r-..... ~ \ .... " ~~ /5 ~['.. r\ 113 ~,... l':\ ...... ~ "" i' ' \ !' ""' 'f\ 'f\'-<..6 ...... :"or-., ~ ~ \ I' \ ....... !">~ i"'-r..... \ ~ ' r\.. ~ \ i' ...... ~~ "" ~4 ~ " " \ ~ ~ =:~J' "-.... ~ 1\ " ~\ "" i"" ~" -~~ ""'"' ~r-. "I\. ~ ~ '""' ~ ~ "1'<7 ,, ~'~ro. ~ ' ~ "~' !""~ t.. "' """ " ./8 """ ~ ~ !" r.-..-...... ~ :' ~ . .. ~ ......... ~r.......... ,......... I) ts 0.~ 0.1 0.0~ GRAVEL SAND Fine Coarse Medium Fine 54.9-55.5 FT. M 54.0-54.4 FT. CL 29.0-31.0 FT. SM 16.0-18.0 FT. SM 44.0-48.0FT. sc 28.0-29.3FT. SC-SM 17.0-22.0 FT. G~-GC 61.0-63.0 FT. SW-SM WATANA RELICT CHANNEL/BORROW SITE D TYPICAL GRADATION CURVES STRATIGRAPHIC UNIT D SHEET 2 OF 10 t-- h 0 !' Jf \i p ! •' 10 l( ll ,. .. t::' 20 ,. }1 , . .. 30 -_l ii ·:~ " H ,, r• t\ t ~ t; • [~ ..c. 01 • 40 ~ "». 4 ... 50 • ... '-0 ,, 0 0 _j_ \i 60 -c ., u .... 5 ~~ 70 Q. \ n ,. 1f II eo !1 --........... I ). ... I'-"-!!loo r -..... -.....iJ 90 -Q -- 0.01 FINES Silt Siz:es :tloy Sizes r--; FIGURE 6. 8 • ------------------------------------------------------------------------------------------------------·----------~ . ~-. . . . . .. ' ~ . . ~ . . .•. .. . .. ..... -.. . -. : . ---------------------- -----------------------------------------------------------·-------------------------------------------------------, ..... .s:: Ot Q) ~ >. .Jl \.. Q) c:. ·-IL -c ~ ~ a.. U.S. Standard Siove Openings in lnchts U.S. Standard SICIY& N~o~rl'l~n 100 12 9 6 3 2 11/2 20 40 so eo too 200 210 :s/4 1/2 3/8 10 -c--~--I I !' I I' ~~::att ,I .I I I I I' - 90 """ ~ v' t\"" ;:: r... ' -~ ~ ~"'I"-~~ I' ....... r---., ~. ~ "'-. r--... -......... 80 I'\ ...... f'. ~ ......... ' ""' t--. r---" r--... ~ !\ ......... ~ ~ 6 r" i'........ /2 1\ 70 \ "'«~ ""' ~ ~ ~ I' ~ ~~ ~ ' ~ 1"-~ €0 ['\. " ~ ....._ ~ I' " /5 c ~ ~ ~ ""' ~ ~ 50 "" ~ ~ v4 '~ """ 1'-""t-. \~ " ~ "' 40 I .... r-.... \0 "" I~ ~ " f'-~oo.. ;; ' r--........ ~ ~~--" ~ 30 _\ .............. "' -\ ~ -' .. 1', 20 10 ; I I ,. 11 ·-·-01000 0.05 too Ql D 5 0.5 500 BOU..DERS I. AH-0168 2. AH-018 3. AH-018 4. AH-027 5. AH-0168 6. OR-1'5 GRAVEL SAND -COBBLES Coarse I Fine Coarse I Mediu~. 1 Fine SAMPLE 168-34 SAMPLE 18-9 SAMPLE 18-15 SAMPLE 27-13 SAMPLE 168-368 SAMPLE 4 64.3-64.9 FT. ML 25.0-27.0 FT. CL-CH 37.0-38.4 FT. CL-SC 60.0-61.2 FT. SM-SC 67.8-68.8 FT SM 26.3-36.0 FT. sc WATANA RELICT CHANNEL/ BORRO\V SIT.E D TYPICAL GRADATION CURVES STRATIGRAPHIC UNIT o• SHEET 3 OF 10 !\ 0 I~ -~ {\ li " H tO lj ), ll !j 20 rl ll f; h 30 F -~ ,r H 40 ~ j; ll 50 1""-I; tr , . ' {I M ~ '"'""' v3 !' j_ ~ "' "'<. "" if "' j 70 "" ,~ r 1'--'" r--l""!o ao ~ ~ ~ ~ ~ ~J 0.01 FINES Silt Sizes lC~oy Sizu FIGURE 6. 8 -s:: Cll ~ .,.. .Q ... • • .... g_ 0 -c ~ u ... • Q.. __________________ _..,. I I U.S. Standard Sieve ·openings In lnchn U.S. Standard Slove Numbtlrt 3 2 11/2 I !/4 1/2 3/8 40 so ao 100 12 9 6 200 270 10 20 100 I I J I i•--~ ~~ I' I' .1 I I I I " ., 90 ~ ~r-==~ :; !:" /2 I ~ ~""--~ " I" ~"'-~ ~ ~ ~ 80 I"' I' f' ~ ~--.....,~ ~""~ ~~ 1' ~ r'-!'-- ~ ~ ""'"' ~ ~ . ~ ""'" 70 -.s: 01 -G> ~· 60 :>. ~"' ~ ~ I'\ l'. ~I ~~ ~ [".. ~ l' ~ ~ ~ "" ~ I' I' """ ~ ' !'-!'., .Q ,_ ;) 50 c: LL ' ~'"' "-.' i'~ ~ r---c:: 40 ~ ~ ..... r-.r-. " "' ~ """ " ...... ~ a.. 30 20 10 u 01000 0.1 !500 lOO· 10 0.!5 GRAVEL SAND ROU..DERS COBBLES Coarse Fine Coarse Medium Fine I. AH-028 2. AH-016 3. AH-028 4. AH-028 5. AH-019 SAMPLE 28-12b SAMPLE 16-14b SAMPLE 28-9b SAMPLE 28-17 SAMPLE 19-12b 24.0-26.0 FT. 30.2-31.0 FT. 18.0-20.0 FT. 36.0-38.0 Ft. 34.3-35.8 FT. CL CL-SC SC-CL sc-cL SM-SC WATANA RELICT CHANNEL/ BORROW SITE D TYPICAL GRADATION CURVES STRATJG~~i-'HIC UNIT M SHEET 4 OF 10 0 lO -! 20 30 «.) ~ I"' ""' .. !s:;n I "f" --~ ~ ' ~ i' ~ .~ ~ ~ -c • f 70 ~ r-o-~-~ """"' ....... ~ !' ... r-..... --['-. ~ 80 ~ ." ~ ·-90 J, I l 0.01 O.DO!S FINES Silt Sizes Cl Sizes FiGURE 6. 8 I ------.. -.. -----.... __ -- US. Standard Sle'lt Optnln;s In Inches U.S. Standard Sieve Number a 100 12 9 6 3 2 11/2 · I 3/4 1/2 3/S 4 10 20 40 eo eo 100 200 210 0 ~~ 90 80 70 I.. Q) 50 c u.. 30 20 10 o,ooo ' ~ ~ ~ ~, 500 BOU..OERS t AH-020 2. AH-0\5 ~ AH-026 4. AH-0168 5. AH-024 If . r-......., I -' I' r\. i\\.: ._...... ~I ! ~ Sa,..... " I" ~ ~· '-~ ~~ t"" .... r--~ 1\ Ja ~ '\ ~ ... l"'l filii ..... r--.,. .. \ ~ ~ !!.ooo. t-- ~ ~ 8b ~" ~"' ~ ~ r""~ r.... ' ~ "' 1', ' ~ "' "":----~t... -'" """ ~ i\ ~ ....... ~"' .... "' ' ' "' ""'i'oo "" ...,. ~"" ' ~5 r-r-... -...... "' "-~ .._ t-"-' . .. r--...... .... ~ I-... ~ lt_a"' ......... N_Gb' I' I' -· ·-. ~--~ ... ~7b ~ ~~ 1'.., '\. -,~ "'"~ ~ ... " ~ ~I'-""' ~ ~ "' ~ 1-~ r-. [\ "<q r\. 1\ ~ ~ ' !\ ~ ~ ·~ I\ ~ ~ " "~ I"'"" 1"'-~ ~ ,:' ""'r-... [\ ' ~ """ '" i'. ~ -...... ~--~ ~ ./4 ' I , ....... ~ f'" ' ""r-;.. i\' ~ ,..,...., """" .......... ~ ""'r.... ...... ~ ' ~ '""" :_...... """ r-...... "" .... 1'--~ ......... ..... ...... '\ ...... .. -..._ r-..... ~ .. ""-.. -....._ I i j 100 0.5 GRAVEL SAND - I I ,, l ' " ~I ~" .\ I' ~ 1'\l ~ v2 ~ ' "' ~ """" ' \ ~~ ('oo. ~ ,, ~ V3 """"" ~ ~ 'i~ i'o.. ~ ""' r.. ~ =~ ~ ~ .......... ~t'-.. ~ ~ ~ ~ ~ .... ~ ~ ' ....... ~ t-11111 ..... ~ "'f:: ~ ~ """""--0.1 0.05 -i r \ : _I r j t !. l; 1 r t; .ll u ~: L ~~ f! j! ,, ~ f II .~ ~ ll ;f 'roo ~ I' ' ! ~ -~ =::-----~~ .... ~"'-..... ~~ ... ~ .. 10 _j~ - 50 «> -.r: alii ~ >. .A to. 50 : 160 t.. g u -c • u '"" .. 70 Q. ao 90 -.......... -iiiiii: ·=.... .. 0.01 0.()05 FINES COBBLES Coarse I Fine Coarse I Medium l Fine Silt Sizes lt~Sites 1 SAMPLE 20-20 SAMPLE 15-7 SAMPLE 26-6 SAMPLE 168-38 SAMPLE 24-5 44.0-46.0 ~T. SM BULK EXPOSURE SAMPLES W82-26 PIT 4 15.0-17.0 FT. SM Ga. 27.0-28.4 FT. sc 6b. W82-26 PIT 4 (W /211 MAX. PARTICLE SIZE) 7L3-72.9 FT. SP 7a. W82-44 PtT 2 14.0-16.0 FT. SM-SC 7b. W82-44 P.IT 2 ( W/2" MAX. PARTICLE SIZE) Sa. WB2-91 8b. W32--91 (W/211 MAX. PARTICLE WATANA RELICT CHANNEL/BORROW SITE D TYPICAL GRADATION CURVES STRATIGRAPHIC UNIT E/F SHEET 5 OF 10 SIZE) GM SM GM SM GW GW-GM FIGURE 6. 8 ______ ,_ ____________ _ -..r:: 0 (I) 3: >• .0 ~ (I) c:: u.. -c:: ~ ~ Q_ U.S. Standard Sieve Openln<;J In Inches U.S. Stan Jard Sltve Numbers 12 9 6 3 2 11/2. I 3/4 1/2 3/8 4 10 2( 4~ 60 10100 zoo 270 -r-r-· I I p • I N 1---.......: l - f-·t-· ...__roo ., -~ I'~ """ 1'-o ~ i'\ " "' ~ -!'. ~ :~ . l\ r'-~ l\ ~ ~ ....... 100 90 b ~ "'I ' ' \ ""'' ~~ 80 \ "' \ "~ ~ i\ ' 1'-r\. 70 1\ i, \ _,5 \ v " \ i\ 60 \ ' \ ~ v6 \ , :\ \ !\ 50 _\ ' ~ 1\ ' ~ 1\ 40 ,, '\. r\ 1'1\ \ 30 ~ '" ~ ' 20 " 10 "" ~ . 01000 100 !iOO 5 O.!S 0.1 .O.O!S GRAVEL SAND I BOLt.OERS I COBBLES Coarse I Fine Coarse I Medium I Fine I. AH-028 SAMPLE 28-48 2. AH-028 SAMPLE 28-47 3. AHoO 19 · SAMPLE !9-46 4. AH-02'3 SAMPLE 23-50 5. OR-. 20 SAMPLE 4b 6. AH-018 SAMPLE 18-26A 7. AH-023 SAMPLE 23-46 8. OR-18 SAMPLE 4a 148.5-150.5 FT. CH 14'3.5-£45.5 FT. CH 169.0-169.4 FT. CL-ML 14·6.0-147.2 FT. ML 50.0-51.5 FT. ML-CL 98.0-100.0 FT. ML-Cl 132.2-133.0 FT. ML 63.0-64.5 FT. SM \\fAT ANA RELICT CHANNEL I BORROW SITE D TYPICAL GRADATION CURVES STRATIGRAPAIC UNIT G SHEET 6 OF 10 n ,c l,~ -~ (: r-~ .. -/1 jj ---10 ,;:,H " y3 ' ' ~ " ~/ .. 2' 20 \ l?\. ' ~ f/4 ' f; \. ~ :i ~ 40 \ i~ \ l:' \ I' ,., 1 \ ~ [,;-50 F i\ \ I\" t.c;.n \ ' 'I,, ,..,..... " 1\ p \ ~ I\ li ·- !; 70 ~\ f'f\. [\ r ~\ ~ I'. _U 80 ~7 ~ ~~-1'-~ ~ " "~ ~ ~~ ""' .............. ' .... 90 ~ """'""""' ~ 0.01 FINES Silt Sizes Jttay S iz:es FIGURE 6. 8 -J:: 01 ~ ~ ... • .. ~ g u --------------------- }()() 90 80 70 -&; Cit • ~ .f"J '::.0.. .c '-50 • c:: ~ -c:: 40 ~ = Q.. 30 2C tO US. StaNiord Sieve Openings lei lndlts U.S.Seondard Sltn NumNrs 12 9 6 ~ 2 1112 1 3/-t 112 ~/e 10 20 ~ I I. I-....,. "'r--~ ~. ~ ~ ~ lfr"' ..,~ I II II ~ ~ 5a -... r--. ~ ......... ~ r"i"'-f'" ~ ....i"o. "'-, ~ r::-::;;:-~~ . . ' ...o;;;;;:: .... ~~ ,~~F""-..... ~ ~ ...... "" "" ""f"'o ., ~ I' ,, r---' ,, ~[' ~ ~ -too.. ............... " ~ ftw> -I"" • r---"" r-.--1-r-. ' r L. .. _ -. ' -I sao 100 D oto so 10 100 200 zro I I I I il I ~ """" / 6b 1"""-o ~ :...... I' ~~ ['-.... l'oo... ~ ~ ~vso..........: ~"" 1--r--~ ~ f' roo-!' "' ~b. ~ ~ i""" !"~ ~ """ R r-.. ~ ~ r" ~~ ~ "' ~ I' ~ " ~ ~r-"" ~ ""'~ " ['. """" ....... f"'~ ~· r-..__ ~ r'-1'.. ~ ~ O.!S Ql 0.0!5 ~ ~ ~ ~ ~I\\ "" ~~ ""' r"-r-.. ~ ~ ~"" ......_ ~ ~ r-oo I' ..... ~ "":--~ ~ ...._ 0.01 ' ! ! I ' t. r .i t· r ' j: { r i l l l l ' i """" ! ~ ~ r ---.. 1- I 1, ...._,J, 0 0 10 20 a.. 50 : '-0 0 u 60 -c: ~ ~· 70 ~ 80 90 aoot 100 I BOU..DERS I COBBLES L_ GRAVEL SAND FINES ~~~--~~=F~iM------~-~--rs-e-.r---~-d-iu-m----~F~m-e---------r------------S-it_t_S~iz~--------~.~.~---Si-ze~s t AH-018 2. AH-017 3.. AH .... 017 SAMPLE 18-55 172.0-173.0 FT. SAMPLE 17-39 102.0-102,8 FT. SAMPLE 17-35 94.0-95.2 FT. SM-SC SM-SC sc BULK EXPOSURE SAMPLES 4. W82-73 5a. W82-2 5b. W82-2 Sa. W82-45 6b. W82-45 PIT 5,6,7 PIT 5,6, 7 PIT 2 PIT 2 (W/2u MAX .. PARTICLE SIZE) {W/ 2" MAX. PARTICLE SIZE) WATANA RELICT CHA~:Na/ BORROW sn·E D TYPICAL GRAOATICi.~N CURVES STRATIGRAPHIC UNIT G' 5·HEET 1 OF 10 SM-SC sc CL CL-ML CL-ML FIGURE 6 ~ 8 ______ n. _______ .-J __ -.r::. Ot ~ ~ >. .0 ~ GJ c: u.. -c: ~ 1oJ a.1 n.. U.S. Standard Sieve Openings In Inches U.S.Stondord SloYe Numbeu 40 60 80 100 200 270 3 2 11/2 I 3/4 1/2 3/8 20 12 9 6 10 100 . . I I I' I I' II I I l )2 I ~~ - 90 ' ~ ..... """"' /I ~ ' --...... -r--~ ............... ... ~ \ ·~fit. """ 80 ........ " " r--... \ v3 "; I ...... ~ i".. !'... ~ 70 ,, '''-. ~, 1"' 60 1'~\ .. 4 \ ~ "' \ 50 ' \ "'~ 1 40 ~ 1- \ , 30 ~ 10 ~ ' 1\ 10 \ .. . 1 " ~ 01000 100 !5 0.~ nr 0.05 uRAVEL SAND BOULDERS COBBLES Coarse Fine Coarse Medium = I Fine I. AH-028 2.. AH-021 3. DR-22 4. DR-22 SAMPLE 28-57 SAMPLE 21-44 SAMPLE 6 SAMPLE 5 2.06.0-206.7 FT. 108.0-108.8 FT. 117.2-118.5 FT. 91.0-98.5 FT. CL ML SM SM WATANA RELICT CHANNEL/BORROW SITE D TYP~CAL GRADATION CURVES STRATIGRAPHIC UNIT H SHEET B OF 10 ·r~ ' •. ;: .5.. ,. i I ' I ' -F ' J r ' l ' l: l \; t r--........~ l - 0.0~ 0~ FINES Silt Sizes FIGURE 6 ~ 8 0 10 20 ~ ..... .r::. at e 40 ~ ,.. 4 L.. 50 ~ .. '-0 0 u e;o ·~ c: .., u '-w 70 Q. 80 90 I I f f JUJ ------~--------~--- -.r::: 0 Q) ~ >. .Q \.. Q) c:: u_ -c:: OJ 0 ~ Ql a... I U.S. Standard Sieve Op«\ings In Inch&~ U.S. Stondord Sieve ~u~ra 3 2 11/2 I 3/4 1/2 3/8 12 9 6 10 20 40 60 10 100 140 200 270 4 100 . 1 t I ll ~ "'~ I P II I I I I I ,, J ~ 0 90 ' ~" I" !'.. ---~ ""' j !--~ f-. ---" ... "" "I- r\. ~~ ~ vi ' I ' ,., t-o'"" :1 K) 80 \ '~ ...._._ r--~-~ ,2 ""'< .l ~ i\ ' \ / "' ' 20 70 ' i,;-5 ' \ ,, ) ~ \.. "\ ' 3/\ "' 1 ") ' 30 60 ' " ~ f'\. ' i l " ~/4 I~ ' l \ ~ .. , 40 50 ""'~ ' \ ' J ..... [', r--... ' ' ' " b. \ ' ,t 50 40 ...... ~'~ \ " \ i ~~ ~ t.... [l "-.. ·i 60 30 ."f'... ~~ ....... 1-----"' ,l 1-. t I I" ~ --..~ i'-t--1'-1~ ' """ " 10 ~ i""'"-["-...... ~~ 'I "'-"" " u " ~ ....... ~ N. 20 ao 10 ""' ... ..... ....,~ :l - ""r-, ~ r--~ 90 u o,ooo 0.01 o.oos 100 Cll o.oe 500 l 0,5 GRAIN SIZE IN MILLIMETERS r-------~--------~r-----.. '--~----------~------------~~------------~----------------~~-------------, GRAVEL SAND fiNES BOU..OERS COBBLES Coarse I Fine CoarsP. I Medium I Fine Silt Sizes ~------~--------~----------~----------~----------- I. DR-18 2. AH-025 3. AH-025 4. AH-021 5. AH-025 SAMPLE 8a SAMPLE 25-19 SAMPLE 25-22 SAMPLE 21-49 SAMPLE 2.5-11 158.3 · 159.6 FT. 53.0-54.0 FT. 68.0-69 I FT. 130.0-131.0 FT. 32..0 -32.7 FT. ML-CL ML-CL sw SM-SW GM-SM WATANA RELICT CHANNEL/ BORROW SITE D TYP!CAL GRADATION CURVES STRATIGRAPHIC UNIT :I SHEET 9 OF 10 ICtoy Sizes i!GURE 6. 8 -./:. ca • :. ,.,. a -• .. ... 0 0 0 -c • u ~ llol Cl f ----------..----------- -.s= 01 (1) ~ ,... .c '- (1) c: u... -c: ~ ~ a.. U.S. Standard Sieve Openings In Inches U.S, Standard SlaY& Numbers 100 IZ 9 6 3 2 1;/2 I 3/4 1/2 318 4 10 20 40 60 80100 200 270 ·r ---··r-I I I 'I' .,... .. I -!'o I I I I I I -r-~ ........: ..___ !'o. 90 ~ \ ........... ~ ~ ·---· k_6 ~ ~ "' ~-~ ........ '-../4 ~ \"' --........ ........ ~ ~ ... 1 .... """' 80 " ~~!"t= ......... "' ' """"' ~ v2 ' ~ ' "~ -r-F--. ~ ~I'-1\ -~ ~ ~ 70 J.i\ "-..... ~r-~~ ' ' "" ~ I " ~ -'\.. -~ ~ ......... . 60 ' ' ~~ '\ ~ '~ ' '-" 5 1 ' ~..;:: ~ ~ """ 50 "'ll i'J1 ' "' ~, " "' ~" ' ~:--..· .... ~ -'-~-~- 40 ~, \" ' ' r........ " .... ..,. r.... \ "" ...... i"--... 30 ...... \(3 i'-._ ~ """" ,_.;-. I' ' 20 " "' r--, ..... f'oo~ ~ ~ ~ 10 ......... ~ I' . --01000 500 100 0.1 0.05 !S O.!S GRAVEL SAND BOULDERS COBBLES Coarse Fine Coarse Medium Fine L AH-0168 SAMPLE\68-73 2. DR-18 SAMPLE 9 3. DR-22. SAMPLE 9 4. DR-2.0 SAMPLE 9 5. DR-2.2 SAMPLE 11 6. AH-0168 SAMPLE 168-72 7. AH-021 SAMPLE 25-55 163.0-164.1 FT. ML-MH 199.l-200.0FT. ML 198t3-l99.5 FT. SM <l> 189.5-195.\ FT. ML 2.38.4-238.8 FT. SM-SC 159.0 -161.0 FT. SC-SM 158.5-158.7 FT. SM WATi~NA RELICT CHANNEL I BORROW SITE D TYPICAL GRADATION CURVES STRATIGRAPHIC UNIT J/J' SHEET 10 OF 10 0 --10 . t 20 I . t\./1 ' i ' 30 ' L \. i ,., 40 \ '" r ! 50 .&::..:'·' \ .. il r\ ' ;, :~~ 1&> "'-' ~ r.; "- . ··.'tl:,:~~· -~ l ~ ' ~ I' ~ . 70 ~ .... """ ' '- .... \"' ..:::: +,--- ~" 80 ~ ' "-R ~ f'--~ 90 ~ ""' .... 0.01 0.000 FINES Silt Sizes Ct Sizes FIGURE 6. 8 ,... .0 .... e • ... g u -c I) u ... :. I I I I I I I I I I I I I I I I I I I c D o' M t- :z ~ u £/F ..,... ..... a.. <{ a:: G (!) !;i a:: ...... (/) G' H J/J' RANGE OF NO. OF SAMPLE DATA DEPTHS ....-------..---------.-------..-----.....-------... POINTS FT. 91 ·z-36.3 24 14.0- 59~0 14 250- 67.0 48 150- 97.6 199 2.5- 166.5 70 34.5- 191.7 40 7.0- 189.3 9 72.0- 209.1 52 29.0- 234.0 10 139.5- 187.0 0 20 40 60 80 ~100 N VALUE, BLOWS PER FOOT (300LB HAM~AER AND 3"0.0. SPLIT SPOON) M1JN.J MEAN L Mhx. Zl STANDARD DEVIATION NOTE. DEPTHS ARE NOT SHOWN ON THIS FIGURE. FOR BLOW COUNT VS DEPTH INFORMATION SEE FIGURE 6.10. WATANA RELICT CHANNEL/BORROW !31TE D COMPOS1TE DRIVE SAMPLE BLOW COUNT DATA FIGURE 6.9 I I 0 I I 30 I I 60 I I i- LLI I.Li' 1.1- 90 :r: 1- I a.. w 0 w _J 0 120 :c I w a: 0 OJ _J <t u I 1-a: w > 150 I I 180 I I 210 I 24 0 I 0 I I ' • X • x~x)j. • x .Y# • x. c X• • • X • .. ) X A • • • • • • • to • • • tl X • • • • e .. • • • • ~i' I I " ~ ~ I I ' ~ ~ ' ¥ ~ i li I l • •.:z;<>'<'ff-'.<:1:' ' t l l i i ' -' w c ' II l k : ' ' . \ ' . ,1 -. l ' ~ ~ I ' I • I:. ~2, AAI (ALL USING 3" 00., 2-3/8'\ D. SPLIT SPOON,.30 11 Di~OP 1 300 LB . HAMMER.) X 1981, AA! (ALL USING i'O.D., 1·3/8'\o. SPLIT SPOON,I8" DROP, 140 LB. HAMMER.) l J I l NUMBER OF POINTS 91, f982 19, 1981 20 40 60 80 ;:?!100 N VALUE , BLOWS PER FOOT WATANA RELICT CHANNEL I BORROW SITE D DRIVE SAMPLE BLOW COUNT DATA UNIT C SHEET I OF 10 FIGURE 6.10 I I I I I. I I I I I I I I I I I I I I 1-w w I.L. :r:: 1-a. w 0 w 5 :r:: w c::: 0 lD _J <t (.) 1-a:: UJ > 0 30 60 90 120 150 180 210 240 0 • X X X X X X X X X • • • I • ~ ~ f I I I ! I ~ I ' ~ ! i '1 I I ;1 I 1! 1 f ¥ ~ ' l l l i w ! ' I l ~ ~ ' I i l 1982,AAI 1 198l,AAI 20 40 60 80 N VALUE, BLOWS PER FOOT WATANA RELICT CHANNEL I BORROW SITE D DRIVE SAMPLE BLOW COUNT DATA UNIT D SHEET 2 OF 10 It • s • . 19 .. NUMBER OF POINTS 24,1982 8, l98l ~iOO FIGURE 6.10 0 30 60 90 120 150 180 210 24 0 0 ( • • • • • J II """" - • l982,AAi •l X 1981 :AAI 20 40 60 eo N VALUE, BLOWS PER FOOT WATANA RELICT CHANNEL I BORROW SITE D DR!VE SAMPLE BLOW COUNT DATA UNIT o~ SHEET 3 OF 10 I ' " I I NUMBER OF POINTS 14,1982 I, 1981 >'QQ ~' FIGURE 6. tO I I I I I ~ I ·I I I I I •• I I I I I I I ..... w w Lt.. ::r::: ..... a. w 0 w ..J 0 X w tr 0 (l) ..J <( u i= 0:: w > 0 0 30 60 90 120 150 180 210 240 0 • • • • • • ~ • • • t It • • .. • . • 0 • • " .. "'"''·' • ' - I I I I l I I I f e 1982,AAI X 1981 1 AAI 2.0 40 60 80 N VALUE, BLOWS PER FOOT WATANA RELICT CHANNEL l BORROW SITE D DRIVE SAMPt F. BLOW COUNT DATA UNIT M SHEET 4 OF 10 • • " •!- f • NUMBER OF POINTS 48,1982 0,\981 -1 3:100 FIGURE 6.10 I I I . I, I I I I I I I I I I I 'I I I I 0 30 60 ""'" 90 UJ UJ IJ.. :c ""'" a.. UJ 0 UJ ....1 0 I 120 :c w 0: 0 CD ....1 <( u i= 0: w > 150 18 0 1---· 21 0 l/'"'1 "' 24 0 .. k xx • " ~ X X • • X • X ~ • X ·x • • • X X j 0 X 0 .. . • • • X • X • k • c • v • -x. f' • "I'\ • xx X • • • X X • t ! • I t • I • • r • • • • it i I I ' I ' £ ' ! ! i i I t I ~ ~ ' 0 ~ ~ ! ; ,, I ~ ~ ; ·' ! ' "' ' ; ! ~} i t • • ~982,AAI I X 1981, AAI 20 40 60 80 N VALUE, BLOWS PER FOOT WATANA RELICT CHANNEL I BORROW SITE D DRIVE SAMPLE BLOW COUNT DATA UNIT E/F SHEET 5 OF 10 c X XX~ ~ . . . ~~ ~ • X .. ' ,. ~ )~ • ~ ~ ~ • 1 ' 1\ ; ~ u r ~ ~ l ~ ~ .. ~ ~ Do ~ : : ·~ " • • • ... ~ ~100 NUMBER OF POINTS 199, 1982 65,1981 FiGURE 6.10 ~~------------,--------~----------------------------------------------~ I I I I I • II I I I I ' I -· I I I I I I I -..._ w w 1.1.. ::X: 1- ll.. w 0 w ...J 0 ::X: w a: 0 ro ...J <t u 1-a: LLJ > 0 30 60 90 !--· 120 150 180 210 240 0 ' . , .. • 0 • X c; • X • • 8 • • • • • • • 1 • • • 9 II tl • • ' ~ • • • • • • • • • • • • • • • • 0 1- • • • •• I 0 ~"'-"'. l • I • • I • • I i It • I • l • ' i I -. •1982, AAI Xl981 ,AAI 20 40 60 80 N VALUE, BLOWS PER FOOT WATANA RELICT CHANNEL I BORROW SITE D DRIVE SAMPLE BLOW COUNT. DATA UNIT G SHEET 6 OF 10 _,,~ ~ •• t j, ~ C> ~ p • ~t ' • ~ p NUMBER OF POINTS I 20, 1982 2, i981 ~100 FIGURE 6.10 I I I I I I I ·~ .. I I I I I I I I I 1 I I I }-w w ll- :I: }-a. w 0 w .J 0 :I: w 0::: 0 m _J <X ',) }- 0::: w > 0 30 60 90 120 150 180 210 240 0 • • • • .1 .... :"-"•"o,~ " .I ~"-·•"'· • • • ' I l ' ' l ~- I • I ' I I •1982, AAI X 1981, AAI .:; 20 40 60 80 N VALUE , BLOWS PER FOOT WATANA REL1CT CHANNEL I BORROW SITE D DRIVE SAMPLE BLOW COUNT DATA UNIT G' SHEET 7 OFIO )> ~ ~ f NUMBER OF POINTS 40, 1982 0,1981 ~100 FIGURE 6JO I • II 0 I I 30 I I 60 I I r-w w 1.1.. ,__ 90 :I: 1- I a. LJ.J 0 w ..J 0 !20 ..,... ...... I w 0:: 0 m ..J <( u I 1- 0:: w > 150 I •• 180 I I 210 I 24 0 I 0 I I 1 l I ~ i I X ~ ' ' ~ ~ ' ~ f ' 't ~ i i ' • ' l • ! ~' ' ~ ' i ~ c ! ·--•t:r:r. -~ I I l ' ,, t ;, ~ ~ ~ ' ,, j ; ~ ' j " l l ! • 1982,AAI ' ' XI981 1 AAI I i i 20 40 60 80 N VALUE: 1 BLOWS PER FOOT WATANA RELICT CHANNEL/ BORROW SITE 0 DRIVE SAMPLE BLOW COUNT DATA UNIT H SHEET BOFIO ~ l NUMBER OF POINTS 9, 1982 11 1981 ~JOO FIGURE 6.10 I I 0 I I 30 I I 60 I ..... I w w tJ.. 90 :c ..... a.. I w 0 w _J 0 [20 :c w I 0:: 0 m _J c:{ u I ..... 0::: w > 150 I I ISO •• I 21 0 I l(1 24 I 0 I I • I . . I I l I • •l982lAAI Xl981, AAI 20 40 60 80 N VALUE 1 BLOWS PER FOOT WATANA RELICT CHANNEL I BORROW SITE 0 DRIVE SAMPLE BLOW COUNT DATA UNIT I SHEET 90FIO " " ) II ~ r ~ f ' NUMBER OF POINTS 52,1982 l, 1981 ~100 FIGURE 6.10 I I I I I I I I I I I I I I I I •J I I I I 1-w w u... J: 1-a. w C) w ...J 0 J: w c:r 0 m ...J <( u 1-c:r UJ > '0 30 60 90 120 150 18 0 21 0 240 0 I ~· ~ ' i I i , i i ! I I l t ·--! ' n 1 ' ! ' ' ! : * f I ~ _1 • e ] ; ;, ii>J' ~ 1• 'r 'I :t i ·~ . I l { I • l •1982,AAI I Xl981 1 AAI I 20 40 60 80 N VALUE 1 BLOWS PER FOOT WATANA RELICT CHANNEL I BORROW SITE D DRIVE SAMPLE BLOW COUNT DATA UNIT JlJ SHEET 10 OF 10 l ll I N p UMBER OF OINTS J I -1, 1982 J-91 1982 J-1, 198~ ~100 FIGURE 6.10 ~-~------~·--------~-~.----------------·---------------------------------~ I I I I I I I I I I I I I I I I I I 2339,6 2320 E ~ 2.300 z 0 ~ i;;22ao ...J w 2260 2240 2151.4 2140 z 2 2100 !;; 2.096.4 > w ::rl 2080 2060 2294.7 2280 ~ w w 1-"- ttl 2260 IJJ -( 0 "-5 40 z X 0 z .~ 2240 ~ > 0 w ..J :I: w 1-a. w Q -I 0 ~40 0 :X: z ~ :X: !i: w Q 80 ~ 40 0 :X: z 80 BOTTOM 0 TEMPERATURE ("C) 0 I 2 3 BOTTOM OF PIPE OR-14 TEMPERATURE ("C) I 2 3 STICK UP· 3.0 FEET (1978) I I I L=.J , PIPE DR-19 TEMPERATURE (•C) I 2 3 OF PVC-\ OR-26 4 4 2.245.7~ 0 2240~-~- ~ 20 1-w w 11. ~ 40 0 :I: z 3: 0 c :X: 1-a... w c TEMPERAn.iRE (•C) -J o I 2 Or----.---.--.----r----, 40 80 2080 2060 i= ;:: ttl .120 w ~ w w ~ 2040 ...J 0 z :I: 0 z i= 3: :; 0 c ~ 202.0 :I: w li: 160 w c 2.000 1980 1960 19~·1.0 1920 _:_ BOTIOM OF PIPE 1900 2.80~----L---------------------~ DR-18 TEMPERATURE (°C) -1 0 1 2 2295.ar: o 2280 i=' 20 w w IL -2: TEMPERA'I tJRE ("C) 0 I 2 ~ -I 2229,1 ~ 0 .--.~...:.......----r----.------,-----, 22201- I STICKUP- 2200 2.0 FEET (1978j I 40 2180 21GO eo 2140 2120 ;:: E 1::1120 ~ ~ 2100 w -' z ~ 0 z i= 3: ~ 2080 0 w 0 -I :r:: w 1- ~ISO 0 2060 2040 2020 2000 240 .. 1980 1960 _,_BOTTOM OF PIPE 280 DR-22 TEMPERATURE t•c) -I 0 l 2 3 -BOTTOM OF PIPE l l LEGEND SHOWN ON FI.GURE 5.21. STICK UP-3.2 FEE'f (1978) -BOTTOM OF PIPE AP-S z 0 ~ 2240 > w ...J w 2000 w <5 40 :I: :X: 1-a. Ill 0 eo i I j I STICK UP-3,2 FEET II 100 ..__c_ts_7_e) _______ ~~---~---' AP-9 WATANA RELICT CHANNEL I BORROW SITE D THERMISTOR DATA SH!=:ET I OF 3 -3 SCALE 1 I 27 •2 :I 0 I I I I I I I I I I 28 29 30 31 32 33 34 FIGURE 6.1! 2. ::S"'l: I I £ g '35 36 37 "'F I I I I I I I I I I I I I I I I I I I 2221.6 2201;\ t: Ul ~ 2180 z 0 i= ~ ~ 2.160 Ul 2140 2276.1 22.60 tZ240 Ul ~ z 0 ~ 222.0 :> Ul ..I w 2.200 1980 2337.9 2.320 § 2300 !:; z 0 ~ 22BO Ul ...1 11.1 2260 2.2.40 -2 0 -2.0 p.. Ul Ul ~ ~40 0 :r. z 3: 0 0 60 :I: t ... 0 80 100 -2 0 _20 1-w kl .!!; ~40 0 ::r z 3: 8 60 :I: t Ul 0 so 100 ~20 ... w w "- ~40 0 :z: z 3: 0 0 60 :z: l-a... w 0 80 TEMPERATURE (•c) -I 0 I ' I i I ' • +BOTTOM ! OF~ I l STICK UP-3.6 FEET (OEC.,I981) I AH-05 TEMPERATURE (OC) -I l .._BOTTOM OF PVC STICK UP-3.7 FEET (DEC.,I9Bil AH-08 TEMPERATURE (•c) 0 I T BOTTOM OF PVC 0 2 3 ~ STICKUP-3.1 FEET (DEC., 1981) JOOL---~-------L----------------~ AH-012 -2: ...... ~ 0 -20 2240 l;j Ul to> .!: Ul Ul Ul 54o !:: 2220 :I: z 0 z ;J: ~ 0 :> oso ~2200 :I: l1J 1- Q. w 0 so 2180 100 -2 . 2319.1 o I ,. 2300 ~ 20 ... w Ul ..... p t:l 2280 ~ 40 !: 0 :!: z 0 z i= 3: ~ 2260 g 60 Ul ..J :r w li: w 0 2.240 80 2220 100 -2 2~:~ro l ~20 23oo E s w u.. ~2280 iii iO u:l2260 22.40 ... l!:. z 3: 86o :r; li: U.l 0 BO TEMPERATURE (•C) -I 0 l 2 3 BOTTOM OF PVC \ 1 I I I I STICK UP-2,6 FEET (OEC.,I98l) AH-D6 TEMPERATURE (•c) -I 0 I 2 3 I I /1 /! I -i-sonoMoF ! PVC l STICK UP -4.7 FEET (DEC.,l9Bll AH-09 TEMPERATURE [°C} -I 0 I BOTTOM OF PVC STICK UP ·2..0 !\'jET (0EC.,I9BI) 100 '--------L----~--j AH-013 -2. "''··~ 0 2220 j:: 20 Ul p.. Ul Ul lL -22.00 ~ 0 fi .. ~ 2.180[ 2160t 2357.8 2340 ... ~2320 I 2: 0 ~2300 Ul -l Ul 2280 2260 22.12.7 22.60 j:: 2240 w 11.1 !:: z ~ 2.220 ~ w ...1 w 22.00 r Ul ~ ~40 0 ::r z ;!': 8 60 :I: t- Q. ... 0 eo 100 -2 0 -20 ... w w !:: ~ 40 0 :I: % 3: g 60 :r 1- ll.. LLI 0 80 100 20 !/40 0 :t: 100 WATANA RELtCT CHANNEL f· BORROW SITE D THERMISTOR DATA SHEET 2 OF 3 TEMPERATURE ("C} -I 0 I +BoTTOM OF ! PVC I STICK UP-1.~ FEET (DEC.,I981) I AH-07 TEMPERATURE (•c) 0 I 2 -+-BOTTOM OF PVC STICK UP·I.O FE,ET {DEC.,I98t) AH .. 010 iEMPERATURE {"C) -I 0 I 2 3 ..._BOTTOM OFPV<i STICK UP-3.5 FEET /! !DEC.,I981) __.!._. ----------J AH-014 TEMPERATURE ~) -2 -I 0 2 ~ 0 2340 20 j:: tsl Ul .!!; §2320 ~40 0 !:: ::r IV ~''""t :z BOTTOM -4. 3: 86o OF PVC ::r ... "- 228Qt w a STICK UP-3.1 FEET (DEC., 1981) 22.60 100 ___ ,._ .. , -·-~-~··-- AH-DH LEGEND SHOWN ON FIGURE 5.21. -2. _, 0 2 3•c SCALE t I I z I I I I ., I t I J 2'7 28 2.9 30 31 32 33 34 35 :36 57 "F FIGURE 6.11 I I I I I I I I I I I I I I I I I I I 2262.7 2260 2240 2220 2200 ~ tLI ~ 2160 z 0 ~ > 2140 ~ 2120 2100 2080 2060 t 2040 I= 2092.8 w ~ ~ 2090 ~ :r r- 11. 20 40 60 eo -~ ~140 160 180 200 220 TEMPER.\TURE (•C) STICK UP 2.3 FEET (SEPT. 1982) -;-BOTTOM OF PVC AH-019 -I STICK UP· 2.6 FEET (SEPT. 1982) TEM PER!ITURE ("C) 0 I l > -f.BOTIOM OF PVC l 2 3 ' ·--'-----···--.~~~------..-,,~4 AH-022 E tLI .... z 0 j:: ~ w -I w 2162.1 2160 2140 20 40 212\ E r 2100 ~ 60 t- . ~ .~ :r l 2080 _ ~ so 1 .g r :r I 2060 ·~ fu 100 I ~ 0 t-. I 2040 r 120 ~.·. 2020 ~140 i- L L STICK UP- ' 3.2 FEET TEM!'ERATURE (•C) • BOTTOM OF STRING ' {SEPT. 1982) !GO '----·-----""--------- AH-020 22727 E tLI !!:> 2260 2240 2220 2200 z 2180 ~ w ....1 w 2160 2140~ 2120 ~!00 2.oao -2. 0 20 40 j:: ll:l 80 .... -I STICK UP- 4.9 FEET (SEPT. 1982} TEMPERATURE (°C) 0 1 I ' -+-BOTTOM OF PVC I AH-021 2080 2060 TEMPERATURE {"C) 0 l 2 3 _ _j AH-023 216~9 2150 2120 L i 840 :c ... 11. w 0 60 WATANA RELICT CHANNELl BORROW SITE 0 THERMISTOR DATA SHEET 3 OF 3 -I TEMPERATURE ('>C) 0 J.. BOTTOM OF PVC ~H-024 ·----' ,,. ____ __l SCALE DATA PLOTTED ON AH-019 THROUGH AH-024 BASED ON ON€ READING IN OCT.,I982, LEGEND SHOWN ON FlGt1RE 5,21 -3 ·2 ·I 0 I 2 1 I I I I I I I I I I I I I I I l 27 28 29 30 31 32 33 34 35 36 ~7" FIGURE 6.11 ~ '"C ~ "F I I I I I I I I I I I I I I I I I I I 7 ~ RESULTS OF GEOTECHNICAL INVESTIGATIONS -FOG LAKES RELICT CHANNEL 7.1 -Introduction During the 1980-81 investigation a review of the site and regi ona 1 geology was undertaken to determine if any other relict channels simi- 1 ar to the previously i dent i fi ed Watana Re 1 i ct Channe 1, existed in the reservoir area. The purpose to find channels which would potentially affect reservoir impoundment. The results of the investigation indica- ted that a bedrock 1 ow may exist in the Fog Lakes area on the south side of the Susitna River. A seismic refraction survey perfor.,rned in 1981 indicated that, in sev1o?ra 1 areas bedrock dropped be 1 ow the pro- posed reset·voir lev.el of Elevation 2,200 {1). For the purpose of this study this area was identified as the Fog Lakes Relict Channel. In 1982 additional seismic surveys and geologic mapping were done to de- fine the geo1ogy, geometry, and gradients of this relict channel (1-ig- ure 3.3). Details of the seismic refraction survey are presented in Appendix C. The following sections summarize the results of these sur- veys and the potential impacts of thi·s area to the project. 7.2 -Location and Configuration The 1 ocat ion of the fog Lakes Re 1 i ct Channel is shown on Fi gt~re 7.1 with the 1 ocat ion of exp 1 orations and the interpreted top of bedrock surface. The width of the channel was defined as that area belcw maxi- mum reservoir level (Elevation 2,200). During the 1981 investigation, the Fog Lakes Relict Channel divided into three areas: east, central and west sections. T.his terminology has been retained for ctiscussion purposes. The west section of the re 1 i ct channel 1 i es between the bedrock "!i gh of Quarry Site A and the bedrock high of the central section. Seismic refraction 1n this area indicate that che bedrock surface is a series of ridges and valleys. Three of these valley, (from 200 to 800 feet wide) fall below reservoir level (Figure 7.1 and Appendix C). The bed- rock surface in these channe 1 s is every where and less than 200 feet below reservoir level, where crossed by the 1981 seismic 1 ine. The west section channels appear to be oriented in a north-northeast direc- tion. Bedrock is exposed across most of the in 1 et area ( 43 500-feet- wide) to an approximate Elevation of 2,000. The central section of the Fog Lakes Relict Channel extends from the edge of the west section channels,. app}"OXimately 4.5 miles east\'lard to the east section channel. Bedrock in this area is relatively shallow and generally flat to slightly undulating. Except for one 300 foot wide channel the entire central section is above reservoir level. This channel is about 20 feet below maximum rese.rvoir level. Bedrock is nearly continuously exposed along the Susitna River across the central section, generally between. Elevation 1,950 and 2,G:J~ The east section of the Fog Lakes · Relict Channel lies bet1t1een the central section and the rock knob to the southeast. This section is 7-1 the largest of the Fcg Lakes channels with a channel width of frcm 6,000 to 7,000 feet wide. The channel consists of a broad area of bed- rock above Elevation 2,100 flanking a steep sided bedrock gorge trend- ing northeast-southwest (Figure 7.1). Seismic refraction lines indi- cate that a bedrock "saddle" exists in the channel where it is crossed by the 1982 seismic line. The elevation of the base of the gorge at this point is about 1940 feet. Within the gorge, the bedrock surface in the thalweg of the channe 1 slopes off to the northeast and south- west, where the deepest observed portions of the gorge are at Elevation 1750 and 1730 on SL82-FL2 and SL82-Fl1, respectively. The nearest bedrock exposed along the trend of the channel is 5 miles to the southwest in Fog Creek at an elevation of about 2$100 feet. The hydraulic head between the minimum gorge depth and Fog Creek is about 160 feet or about a 1/3 percent gradient. 7.3 -Geology (i) Introduction The geo 1 ogy of the Fog Lakes area is shown on Figure 4.1 and has been based on reconnaissance 1 evel surveys and seismic refraction surveys. The following sections discuss the sediments, bedrock, ground water anj permafrost in the Fog Lakes Relict Channel. (ii) Sediments Three types of sediment were de 1 i neated in the Fog Lakes Relict Channel (Appendix C): (a) Surficial deposits, {b) Poorly consolidated glacial sediments~ and (c) Well consolidated glacial sediments. Surficial deposits consist of a layet 0f 1,300 to 5,000 fps material~ This layer is generally discontinuous, ranging from 0 to 40 feet thick, except in SL82-FL1 where it ranges from 10 to 85 feet but is usually less than 40 feet. The :-;urficial deposits overlie bedrock in the central section ~~~ on the southeast end of SL82-FL1, and the glacial sedi- ~etts in the channel areas. The glacial sediments consist of material ranging in seis- mic velocity from 4,300 to 11,000 fps. The boundary be .... tween the poorly and we 11 con so 1 i dated sediments is not distinct but appears to gr·ade laterally. Velocities of the poorly consolidated saturated material is generally 4,600 to 7,000 fps. The velocities of the well consolidated materials are from 7,000 to 11,500 fps. This material may be partially to completely frozen. The glacial sediments 7-2 I I I I I I I I I I I I· I I I I I I I I I I I . I I I I I I I I I I I I I I I cccur primar"ily in the deeper channels. In the east sec- tion ch;jnnel the materia1 is up to 580 feet thick. High seismic velocities of this material indicate probably well consolidated material. In the west channel the glacial sediments vary from high to low velocity indicating varying degrees of consolidation. Thickness here reaches a maximum of. 270 feet. Overall, the thickness of the glacial sedi- ments is less than 200 feet in the channels. Outcrops of the glacial sediments are rare. Only till was . observed in the outcrops; however, it is likely that other types of glacial sediments such as outwash niay be present. (iii) Bedrock The bedrock in the Fog Lakes Re 1 i ct Channe 1 consist of a variety of rock t.:,rpes, as inferred from bedrock exposed along the Susitna River and at Fog Creek. The west section of the channel is underlain by diorite 13ordered by andesite porphyry to the west and argi 11 i te and graywacke to the east. Bedrock beneath the centra 1 section appears to be argillite and graywacke. The east section is underlain by Triassic volcanic rocks. The contact between these volcan- ic rocks and~ the argillite and graywacke is interpreted to be the Talkeetna Thrust Fault (10, 11, 16, 24). The trend of this fault is nearly coincident with the east section channel. The trend of the east and west Fog Lakes Relict Channels aligns with the present northeast-southwest drainage trends of the Watana and Deadman Creeks, respectively. This suggests that the drainage at one time was conti nuc :s across the present location of t~e Susitna River. The east section channel is broad with a deep gorge superimposed on it, similar to the present day Susitna River valley. It is possible that the original broad channel was the result of glaciation followed by fluvial erosion of the gorge. Later glacial processes filled in the channel. ( i v) f. round\tJater and Perma.frost No addition a 1 data on groundttJater and permafrost were ga- thered during the 1982 field investigation. A discussion of these parameters is presented in the 1980-81 Geotechni- cal Report {1). 7.4 -Engineering Impacts (a) Introduction As with the Watana Relict Channel, the potential engineering impacts of the Fog Lakes Re 1 i ct Channe 1 are seepage and 1 i quefac- tion potential. Surface flow are not considered a potential 7-3 problem in that the topographic low in this area is at a m1n1mum of Elevation 2,300, one hundred feet above maximum flood level. (b) Leakaae Estimated maximum gradient from maximum pool level to Fog Creek is about a third percent over a maximum possible flow area of 8,000 feet wide by an average of less than 150 feet deep with a 5,..,mile flow path.. To a chi eve a flow in excess of 60 cfs, the average permeability over th~s area would have to be approximately 5xlo-lcm/sec. This high an average permeabi 1 ity would require an extremely clean sorted gravel or sand over the entire area. Although no borings have been performed in this area, the geologic history and seismic velocitites measured in this area indicate significant presence of densely compacted glacial tills which are expected to exhibit permeabilities in the range of Io-3 to lo-5 em/sec. Although drilling should be carried out in this area to confirm the seismic data, the Fo'!J Lakes Relict Channel is not considered to have any significant economic impact on the project as a result of leakage. (c) Piping The potential for p1p1ng failure is not considered possible due to the low gradient and long flow path (about 5 miles). (d) Liquefaction Liquefaction failure would require that three conditions be pre- sent: (a) material of low relative density which is saturated, and caul d thereby be shaken to a denser ,·tate or trend to "flow" under earthquake vibrations; (b) exposure of this unit to or near a free surface so that it can escape confinement; and (c) continuity of the unit from the free surface to the point where the topography is low enough to cavse breaching. For the Fog Lakes Relict Channel, it is highly unlikely that a liquefiable unit exists in adequate continuity, thickness, and susceptibility that a section of reservoir rim could fail to a depth of more than 100 feet. This magnitude of failure> on a ground surface with a slope of not more than 5 percent, \'/ould involve probable quantities in excess of 30 million cubic yards. Field verification by drilling will likely dispell any concerns regarding liql:faction. 7-4 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ' \f't;,(:J/ WATANA FOG LAKES RELICT CHANNEL TOP OF BEDROCK .; . .-~ r : " .. ~ ....... " '225•::l .....- .,..-r--l"'"i>.~:~ ·" ..;-< ' _)r._.. ,. r-:-~~~0"; ::. .... ·~o.,: .. · .. ·····~··:·- _ .. ,z~-- ,. ,\ '\ ~·,;··/--1~-:.~;~.:-.. ;.. _,.. .... ~_---·--~;,~"'-' .... t"'~ -•""->-.-. ---~:;..·-:. ''il ~;·""-?::=.;;.·~ -'-~~:ijf.ro~~S3 (' LEGEND: LITHOLOGY: ~ BE_DROCK OUTCROP OR SHALLOW BEOI'roCK, ~ 'UNDIFFERENTIAltD. C'iNTACT: BEDROCK /SURFICiAL DEPOSITS, Af'PR(XQ)}.ATE. CONTOUR LINES: TOP OF BEDROCK, CONTOUR INTER'"'L 100 FEET. TOPOGRAPHY, COtiTOUR INTERVAL 50.0 FEET. TOPOGRAPHY, Et... ~250 CONTOUR OASi£0. NOTES: I. BASE MAP MODIAEO FROM U.S.G.S. TALKE'E11NA MOUTAINS ·'l;I-S AND 0-4 QUADRANGLE MAPS, SCALE I~"~'Mt 2. SEISMIC LINE SECTIONS SHOWN IN A?PtNcy;x: D AND AAI •. ·~'2. 0 2.000 4000 FEET SCALE 2222-;""""-"'iiiiiJ FIGURE 7.1 I• I I I I I I I I "' I I I I I I I I I I 8 -RESULTS OF GEOTECHNICAL INVESTIGATIONS -QUARRY AND BORROW SITES 8.1 -Introduction During 1982 additional irtvestigations were carried out in the quarry and borrow sites.. The principal emphasis of the program was in Bo.rrow SiteD, whereas additional wor·k in the other sites principally ton- si sted of continuing instrumentation monitor·ing and long-term 1 abora- tory testing. The results of the work performed during 1982 are pre- sented in the following sections. Locations of the quarry and borrow sites are shown in Figure 8.1. 8. 2 -Quarry Sites (a) QHarry Site A The only work performed for Quarry Site A (Figure 8.1) during 1982 was the completion of the long-term freeze thaw durability testing begun late in 1981. As shown in Table 8.1, the rock samples ~01- lected from the andesite and diorite rock {Samples WB0-303 and 80-304) showed a maximum loss after 150 cycles of just over 2 per- cent by weight, which would be considered excellent rock for con- struction material ~Table 8.1). No indication of any softening or deterioration of the rock was noted confirms previous testing per- formed by the COE (2) which showed the rock to be very resistant to wea\.hering. It is concluded that Quarry Site A rock represents a good source of thermal and water..-deterioration resistant rock. If Quarry Site A. is to be developed, further testing should be conducted during final design to determine which areas 01 the site would produce the highest quality material, dejlth of weathering and natural gradation resulting from blasting. Use of the ande- site in the quarry area will be dependent on its degree of weath- ering. Use of the quarry rock for concrete aggregate would depend on the results of reactivity testing. Work performed by the COE (28, 30) indicate moderate to high presence of potentially reac-. tive constituents in the andesite and andesite porphyry. (b) Quarry Site B No further direct exploration or testing was conducted in Quarry Site B. However, the Watana Relict Channel area mapping and seis- mic 1 ines did extend into this area. This mapping confirmed that any quarry operation in this area would involve difficult over- burden slope stab i 1 ity, access, and adverse haul gradient pro- blems. 8.3 -Borrow SiteD {a) Introduction Borrow Site D is the identified source for impervious/semi- pervious construction material (Figure 1.2). The borrow site was 8-1 further explored in 1982 in the course of the investigations for the Watana Relict Channel. The objective of the 1982 program was to further delineate the Borrow Site's stratigraphy and material propertiesp Results of that study are presented below. (b) _l:.o.cation and Geology (c) The borrow site lies on the southern corner of the Watana Relict Channel area, abutting Deadman Creek on the east, the Susitna River Valley on the south, and extending to near the exposed bed- rock at 11 The Fins 11 on the west, near the damsite (Figure 8.1). The general slope of the area is gentle towards the south. The surface topography forms swal es, benches, and terraces up to 50 feet in height. PhJtos of the topography and vegetation are pre- sented in the 1980-B1 Geotechnical Report (1). The geology of the borrow material is described in detail in Sections 6.3 and 6.4 (Units C through F) and the stratigraph·ic sections of the combined Hatana Relict Channel/Borrow Site D areas are presented in Figures 6.1 -6.6, along with typical photos of the materials in Figure 6 .. 5. Generally, the borrow material is composed of ice disinte- gration, alluviC'l and outwash types of materials, generally not exceeding graveL size with some zones of cobb 1 es and boulders (Units C, D, E, and F). Local zones of till (Unit M) and lacus- trine sediments (Unit D') exist in the area as described in detail in Section 6.. This material overlies a 1 acustrine deposit of sandy silts with some clay (Unit G). Material Quantities The overall quanity of materials, which includes a11 of Units C~ D, Dt, M, E, and F, has been estimated at about 180 million cubic. yards, over an area of approximately 1130 acres. This area repre- sents all the desirable material above Unit G between Deadman Creek, the Susitna River Valley, and a northeastern and northern boundary 1 ine drawn for topographic considerations. Th-'"' material extends to considerable depth!t as indicated on the borro\f: material isopach map (F·igure 8.2). The northwest 1 imit of the borrow area was established by the presence of Unit G very near the surface, and by the requirement that borrow site development not remove the topographic crest forming the reservoir rim in the buried channel area~ The total volume of potential borrow material equals an average of about 100 feet of excavaticm over the identified limits of the borrow .site. Based on the borrow materia 1 isopach (Figure 8. 2:t Sheet 1), the thickest deposits are along the Susitna River and Deadman Creek. The selection of the fi n?l borrow pit location ~~11 depend on material requirements, permafrost locations, envi- ron,nental factors, and haul distance. 8-2 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ·I I I I I I I I The major portion of the borrow material, that which exhibits the most consistent suitable properties, is Unit E/F. This unit, which 1 ies directly on top of Unit G, is an .out\'tash (see Secticn 6). The estimated quantity of Units E and F in the borrow 1 imits is 133 mill ion cubic yards, or about 75 percent of the total vol- ume above Unit G (Figure 8.2, Sheet 2). These materials can be found near the surface in the central and northwest portions ot the area, whereas the overlying units are thickest to the north- east and south sides. Based on 28 borings; the overlying weath- ered and or.ganic zone range from 0 - 6 feet, averaging approxi- mate1 y 3 feet. As may be s·een from Figure 6. 7, bedrock is deep throughout the area, generally more than 100 feet deep, below grade throughout the area. (d) Material Properties The material properties defined in the 1980-81 Geotechnical Report (1) remain generally unchanged. The work conducted in 1982 re- sulted in only minor modifications to average properties or ranges. -Gradation The grain size distribution, which are presented as typical gra- dations in Figure 6.8, are shown in Figure 8.3 as bands of all observed data with the mean and plus and minus one standard deviation band shaded. These curves include all usable data from the COE and the 1980-82 Acres prograns. A plot of auger/ rotary core samples versus test pit samples reduced to 1 inch maximum particle size show identical mean gradations. This con- firms that samples from soil drilling in the area are repre- sentative of the in-place material provided allowance is made for over 2 inch size material as indicated by the gradations of the complete material as taken in test pits (Figure 6.8, Sheets 1 and 5). The range and nllllerical average gradation curves show that Units C, D, and E/F are similar in grain size and distribution. Units o• anJ M have some significantly finer gradation and wider devi- ation (Figure 8.3), and they are not considered suitable as bor- row material. Selective mining may be required in borrow pit developnent to avoid some of the finer materials that may occur in thin layers of lenses. The range and means of Unit G grada- tion is presented in Figure 8. 3 for comparison purposes si nee Unit G is considered unsuitable for compacted fill construc- tion. The general gradation ranges preserited in Figure 6. 42, Sheet 2 of 2 of the 1980-81 Geotechnical Report match the typical samples (Figure 6.8) for Unit C, 0, and E/F and includes most of D • and M. 8-3 ~ Moisture The composite moisture data show a fair'iy consistent mean mois- ture of around 11-12 percent for the borrow materials (Figure 8.4). It is evident that Unit G's high moisture (23%) makes it un acceptao 1 e for construction use.. · The moisture contents for the various units show a definite trend toward higher moisture in the samples with more fines, with Units 0 and 0' having the highest fines content in the bor- row materials (Figure 8.9). The average moisture in the borrow ~ materjals of 11.6 oercent could be reduced (if desirable) by wasting the finer m:terial by select mining. Approximately 25 percent of the samp:~c; are above the mean (Figure 8 .. 6) while about 75 percent lie ;Jaw the mean. This fact, combined with the bias of sampling 1ere the finer, more plastic materials have higher sampling recovery, suggest that the 11.6 percent average natural moisture as calculated is higher than the true average for materials 1 ikely to be utilized in the dam. -Atterberg Limits The Atterberg limits for the various stratigraphic units are summarized ih composite form Figure 8.7 with all data presented by stratigraphic unit on Figures 8.8 through 8.11. It is evi- dent that the borrow material contains relatively low plasticity materials while Unit G and the tills have the high plasticity and cohesive materials. The data ._,resented represents the means and ranges of only those samples which were apparently plastic and hence were tested base,· )n field observation and do not rep- resent a statistical per" :nt of plastic versus non-plastic material .. Therefore, the mean p1asticity and plastic index of the borrow materials will be near to zero and to obtain a pl as- tic material one would need .to produce from Units 0', G or s• and possibly Unit I. -Proctor Density Tests Due to the 1 imitatinns on sample ·sizes, only face exposure samples were tested in a Proctor mold in 1982. Because the m)terial moisture content in the borrow materials is relatively high, the Standard Proctor rather than Modified Proctor tests were performed so as to enable more accurate determination of the optimum density data point. Figure 8.12 shows the range of all Standard Proctor tests to date with the maximum densities between 128-134 pcf at about 8-9 percent optimum moisture con- tent for UnitE/F. As seen in Figur·e 8.12 through 8.15, 90 pel"- cent Standard Proctor density should be obtainable at natural moi stur'e. Figures 8.16 and 8.17 shov.f the Modified Proctor test results to date on Unit E/F and Unit G, respectively. They illustrate that 8-4 I I I I I I I I •• I I I I I I I I I I I I I I I I I I I I I I I i I I I I I the change from Standard to Modified Proctor specification would add only about 5 percent greater density. Figure 8 .. 17 illus- trates the low maximum density and very dry (rel?.tive to the 23 percent natural moisture content) optimum moisture content of Unit G material. · (e) Ground Water Regime As discussed in Section 6, the ground water regime in the Borrow Site is highly complex due to perched water tables, aquicludes, and sporadic permafrost. Basically, the Q\"ound \'later table seems to perch on frozen and impervious Units D', M, and G. Surface water is perched on frozen or on silt pockets in Unit A, B, and C. Because of the impervious characteristics of Unit G, and possibly portions of locally D' and M, locally trapped and perched aquifers likely exist throughout the coarse cobb.1y and bouldery material in the bottom of Unit F which probably acts as a principal aquifer. Natural surface and subsurface drainage on the borrow site is believed to be predominately to the south. (f) Permafrost Regime Thermometers readings indicate that a significant portion of the borrow materials are below freezing in the ll{latural state, however, no temperature below -0. 2°C have been detected during drilling or by the various thermistor installations below the active zone (Figure 6.11). Very few borehole samples recovered show visible ice or ice lenses from the borrow material and the only unit with significant frequency of temperature$ below zero with visible ice crystals and lenses is Unit G below the borrow materials. The instrt..-nentat ion ground temperature summary sheets (Figure 6.11) shows envelopes with depths of zero annual amplitude and active zone around 25-40 and 10-15 feet, respectively in most areas. The most extreme depth of annual amplitude is about BO feet. Only four borings show possible stabilization below freez- ing. There is no appar-ent correlation with locale or strati- graphic unit for these cases~ These holes may have been drilled in remnant frost bulbs in the old ice disintegration deposits, i.e., relict pingos, ice wed~es, or palsas. While there is con- siderable surficial evidence of permafrost structures, only a very few areas in Borrow Site D has any evidence of current permafrost activity. From the evidence to date, it is considered that permafrost in Units C, and E/F does not affect material suitability and that frozen areas (where encountered) could be bypassed in mining. 8. 4 -Borrow Sites E and I The 1982 investigations in the granl!lar borrow sites were limited to surficial geologic mapping in Borrow Sites E and I and completion of the concrete aggregate suitability testing begun in late 1981. 8-5 (a) Geo 1 ogy The geo 1 og ic mapping of Borrow Site E and I were performed by aerial photo interpretation and recormai s~ance m~~}.ppi ng. The re- sults of the mapping are presented on Figures 8 .lg and 8 .19. The mapping did not reveal any conditions which woulj change the dat& assumptions or reserve calculations presented in tile 1980-81 Geo- technical Report (1). (b) Material Properties Freeze-thaw tests performed on aggregate from the Borrow Sites showed losses of 2.3 to 7.8 percent after 140 cycles (Table 8.1). 0 The results of the absorption, soundness and abrasion test shows that the aggregate meets the applicable standards for general structural and dam construction ~stabl·ished by the .American Asso- ciiltion of State Highway and Trar~sportation Officials (5) and American Society fot" the Testing o1· Mater·ials (4), U.S. Army Corps ·of Engineers (31, and the U.S. Bureau of Reel amation (33) (Table 8.2). Results of reactivity testing of the aggregate with cement is shown in Table 8 .. 3. The results indicate that adverse reactivity is negligible as all data falls well into the zone considered as innocuous (Figure 8.20). 8 .. 5 -Borrow Site H No work was performed in Borrow. Sit-e H except for the continued read- ings of the thermistor strings installed in 1981. Although preliminary readings in 1981 indicated potential permafrost in several of the holes, readings performed in 1982 showed no temperatures at depth below freezing (Figure 8.21). Readings over the past year show one boring ( AH-H -5) may be bel ow freezing near the bottom of the ho 1 e, but the other probe installations are showing temperatures below the active zone (approximately 8 feet avet'age) of about +1 oc indicating that wil~t . per·mafrost existed at the time of drilling ~:~as so clnse to thawing and contained so little fro·zen r~rater that refreezing i~ highly unlikely. The depth of annual frost penetration appears to be related more to vegetation cover and sunlight exposure than to watertable cr presence of frost. The depth of zero annual amplitude ranges from 25 feet to greater than 45 feet (Figure 8.21). 8-6 I I I I I I I I I I I I I I I I I I I I I I I I I I I I FOG LAKES RELICT CHANNEL ~ ., .'-WATANA RELICT CHANNEL ~ ' .. :'~\··. '-. . ' . \ :,, ~ .. ' \. \' ''}BORROW ~'~EF H . f~ ~ I I \ . SITE C f .. \BORflOW \ ~ , ~-( I I I l I ' ) \,_j .. ....,.,.· WATANA BORROW SlTE MAP LEGEND c.=='] BORROW I QUARRY SITE LIMITS ~ t MAP INOE>: 31iOWN ON FIGURE l4 0 ~-~-.;,..,~-g; MILES FIGURE 8J •, ,--- I I I I I I N 3,224 0<'!.1 ___ I N 3,22~6_,,o,_,oo,_· __ _ I I I I N3,232,000 I I I N 3,235,000._, .• , I I I I I !: gl oi 8l QJ o' ~~ Cl)i uil ~ lni U'>i ..... ~ r--~ Wl W' Ulc I 01 8i ·t ~~ W• '6 0 ' I LIMITS OF BORPC''< SITE D 8' Q 0 ~") "" \IJ Oc 8' 8 8 8' Oi 0 0' o_ q 0 aS w' v t\l 0- ~ ..r· v': <t :. ""' 1'-. .... t1l .W w w w ~ '\OAM AX\S. \ WATANA BORROW SITE D tSOPACH MAP OF ANTICIPATED BORROW MATERIAL STRA1"1GRAPHIC UNITS C THROUGH F SHEET I OF 2 LEGEND: -IOO-ISOPACH CONTOUR (LINES OF EQUAL .BORROW MATERIAL THICKNE;<:::-1 ~ SOREHOLf.S PROVIDING CONTROL FOR SORROW MATER1A.. •j THICKNESS. ' , l ! i ~· I 1 i :1 l ' j NOTE: I I. ISOPACH OF BORROW MATERIAL EXTRAPOLATED fROM TOP Cl= 1 UNIT G CONTOURS FIGURE 6.6 SHEET 2 OF3 ANti T¢f' Of GRotr!'C j CONTOUR MAP. ~ FIGURE 8.2 I I 1 l :( I t 1 • I 't 1 i l I I I I I ! 8! I ~ }!:! u; I N t5,224,000 I N 3,226,000 ·--, I I N3.228.000 I N3,230,000 I _N3,232,000 I I I I " I • N 3,238,000 _ I I I' li' I oj ol ol 8r Oi <01 ~ ..,., ~i "'' ,...., wj W! 0 In I l oj ~ fell 1'-; W! l I.IMITS OF BORROW SITE D I gl ~1 c, le· w) l ~ i ; 81 0 0 81 0 0 0 0 o' o_ 0 0~ 0~ .,51 "' «? N' 0 t! v ,., ~· Q ..... ,... ~"-' f-.! ui ! 1JJ w WI w --........ WATANA BORROW SITE D ISOPACH MAP OF ANTICIPATED BORROW MATERIAL STRATIGRAPHIC UNITS E AND F LEGEND; '-100-.. • NOTE• ISOPACH CONTOUR (LINES OF EQUAL SORROW MATER:i!it.. THICKNESS) SOREHOLES PROVIDING CONTROL FCR SORRO\'l MAIEi'J:!L THICKNESS, 1. ISOPACH. OF BORRvvr MATEPIAL EXTRAPOlATI21:1 FROM TOP ::F UNITG CONTOURS FIGURE 6.6 SHEET 2 OF3A..~O TOP OFUNi":" E/F CONTOURS FIGURE 6.6 SHEET I OF 3. 0 lOOO 2000 FEET SCALE ,, h • • 'j SHEET 2 OF 2 FIGURE 8.2 ~------~-----------------------·--------------·---------------------------------------------·-------------------------------------------~~~~~~----~~====~ • • : -· •• '*. .... t: " . . \b.,.' . .:.· .. "' ' . ... \ .,_.,. .,. • • .;, ... ,... . .;; t.:·:f ... .,. • ~ \ -• ~ ,. ~ • ~ :. .~. #I : • ' •• .;. ...... ,. ~' ; • "J •·• ". .. ---- --- ----------'· - -;.r. 0' Q) ~ >- ..0 .... .Q) c: lL -c: ~ \..; a; a_ U.S. Standard Sl~v• O~lngs 1n Inches U.S.Standa,:l Sieve Numberc Hydrorn.hsr 100 12 9 6 3 2 11/2 l ~/4 1/2 !/8 0 40 60 80 100 200 270 20 10 --....... ~· r 11 ~ -II I I I I !I . ~ ~ r"lllll cl ---. ! ~i'llll'lr.. ........ -' 90 10 "'--.... ....._ ~ ~ ~ ~ ~ I t i-~-~ ' ,.., "' 1'\ ' . ~ "" "'t--. '-r-., ' 80 20 I ~ ' ~--'"' I' ~ I .. . " ' " ' ... ~. ~ '~ ,...._, ~ . 70 60 50 30 -J.: Cl' .. 40 ~ ~ ~ 50 • !II .... 0 I "~ ' -~ ~ ' " .. ·. ' 1'\.. ' i I' ' ' .' :' "" .. " ~ ~ i 1'. ' 1--~ ~ ' ' " t ' : I f'""' -......, ~ .. ~~ : ' . . ~ ' .. : -' ~-·.· _--~ . . ... ' ~ N ' ..1 ~ i ~ ' .... -~ -~ " ~-'-.. . !\.. 40 30 0 u 60 -c <IJ 0 I.. ~ 70 Q. I I I I ~N. .: -->~ .. ~" ~ ·. ~ LOWER LIMIT i"o.. 1 _UPPER LlMIT ---ENV"£L~PE ....... f"' ~ .. :"1!~ ENVELOPE -..:.~ ........ '-~ i'.... ... Ill. " ............. ~ K ' ~ ~ " Jf [1 ,. ~ .. ,_ _,~ ... ........... ' ! N ~ . 80 ' . . ~ -~~ ! ...... ' f'oo~ i' \t ...... if i ""'i'-.. ' ~~ -~ ~--. ~ t:'--.1 l ~ L ... ~ t~ ... 20 90 10 .......... ~ -·~ -~ ~ r-...... " ~~ ~! i -....... ..... ~ "" r"' .. ~ ~ _,_ ~ i '-.. ~----~~ ~ ~ ""'"'"' '--'----j__I_J . I ~ _,; -0 tooo 0.01 aoot 100 ~00 100 5 0.5 Ql 0.05 BOU..DERS COBBLES ~GRAVEL SAND FINES Coarse I Fine Coarse 1 Medium _l Fine Silt Si1.es lCtay Sizes NOTES NUMBER OF POl NTS = 78 I. STATISTICAL DA1.A BASED ON SAMPLES RECOVERED :t,J 3 n 0.0. SAMPLER. 2. FOR TYPICAL GRADATION CURVES OF EACH STRATlGRAPHlC UNIT SEE FIGURE 6. 8. WATANA RELICT CHANNEL/BORROW S1TE D COMPOSITE STRATIGRAPHIC UNIT C GRADATIONS SHEET I OF 6 L~\:~ND ·-cr x~ --CT ~ FIGURE 8.3 ------------------- I I 90 80 70 -t; 01 ~ s 60 :>. ..Q '-0" 50 c: u... -c: 40 Gi U' \...; G1 CL 30 20 tO U.S. 'Standard Sieve Openings In lnchos U.S. Standard Slelfe Numben . BOU..DERS COBBLES GRAVEL Coarse I Fine ~~OTES I. STATISTICAL DATA BASED ON SAMPLES RECOVERED IN 3" O.D. SAMPLER. 2. FOR TYPICAL GRADATiON CURVES OF EACH STRATIGRAPHIC UNIT SEE FIGURE 6,8. Coarse ~AND I Medit•m I Fine WATANA RELlCT CHANNEL/BORROW SITE D COMPOSITE STRATIGRAPHIC UNIT 0 GRADATIONS SHEET 2 OF 6 I I ,., FINES Sitt Sizes lt~ Sizes NUMBER OF POINTS= 33 FIGURE 8.3 ______ ::.0_, ______________________________________ _, _________ _,.----J .... ------... -,----.. --.. US. Standard Sieve 0p9fllnos in Inches U.S. Standard Sieve N1.1mtxlrt 01000 500 100 BOll.OERS Fine GRAVEL COBBLES NOTES I, STAT!STICAL OATA BASED ON SAMPLES RECOVERED IN 3 11 0.0. SAMPLE~. 2. FOR TYPICAL GRADATION CURVES OF EACH STFtATlGRAPHll' UNIT SEE FIGURE 6. 8 . Ql 0.0~ WATANA REL~:._,_,. CHANNEL/BORROW SlTE 0 COMPOSITE STRAliGRAPHIC UNIT D' GRADATIONS SHEET 3 OF 6 O.Ol QOOIICO Silt Sizes NUMBER OF POINTS : 12: r--.. ; • I FIGl}RE 8. 3 ~----------------------------------·~----------~----------------------------------------------~--------------~ ----------------~-- !) -.c 0 CP 3: ,... ..0 \., Cit c: ·-u_ -c: ~ ~ CL U.S. Standard Sieve Optnlngt In lnchu U.S. Standard Slcvll Numbers 100 [TTl! I~ 9 . t 6 I 3 i' 2 11/2 I ~4 1/2 3/8 4 ~~;.:>:t·~ fl 10 20 I 40 I 60 80 100 200 270 I I l I 90 80 70 60 50 40 30 20 GRAVEL BOULDERS COBBLES Coarse Fioo NOTES I. STATlSTICAL DATA BASED ON SAMPLES RECOVERED IN 311 O.D. SAMPLER, 2. FOR TYPICAL GRADATION CURVES OF EACH STRATIGRAPHIC UNIT SEE FIGURE 6. 8 SAND Coarse Medium Fine WATANA RELICT CHANNEL/BORRCM' SITE D COMPOSITE STRATIGRAPHIC UNlT M GRADATIONS SHEET 4 OF 6. f"INES .::::: l ltttl)l Sizes I .:,nt Sizes NUMBER 0 F POl NTS = 3£ FIGURE 8. 3 ----------181-----~-- -.s::. 0 ,.. .Q l... (I) c: 1.1.. -c: ~ ~ 11. U.S. Standard Sl•·• 01*\lnQS In Inches U.S. Standard Sieve Numbers 50 40 30 20 10 0 Jooo ~00 ......-----..,-------.------::::==-:-------,-----·-·· ·--~=------r------·--~:-:::::::------------, GRAVEL SAND FINES 801.LDERS COBBLES ~---~~~----+---~----------~------1----------··----------~----~ Coarse I Fine Coarse I Medium Fine Silt Sizes Cla Sizes ---~--------~------------------------~~--~ NOTES I. STATISTICAL DATA BASED ON SAMPLES RECOVf~EO IN 3 11 O.D. SAMPLER. 2. FOR TYPICAL GRADATION CURVES OF EACH STRATIGRAPHIC UNIT SEE FIGURE 6. 8 WATANA RELICT CHANNEL/BORRON SITE 0 COMPOSITE STRATIGRAPHiC UNIT E/F GRADATIONS SHEET 5 OF 6 NUMBER OF POINTS = 137 FIGURE 8. 3 -.... -- - -.. - --·-·---- - - - -.r: 01 (p 3: >- .Q .... Q) c: u.. -c: ~ ~ a.. U.S. Standard Sieve Openings in Inches U.S. Standard Sieve Numbers 3 2 11/2 I 3/4 1/2 3/8 12 9 6 4 10 20 100 r-~ ·--·· I I I ~ .· .· ..... r •· ,, t' !!l ,. .. 90 "'q ' ·, :""'~" ~ ~ ~-.. ~--· ,__ ---...... ~ ~ ~~ 80 ~ !"'I ... ~ ~--..... I I -...... I 1\. '; 70 ' '"' --~....: ~ 1" t\. 60 " "'-t 50 40 -........ f'l>o LIMIT-""' r--. ...... l LOWER !Ooo.. 1 ENVELOPE ; ......... ~ f--I -......... ....... - 30 l ~':-- 20 j ' l 10 I! I -01000 500 100 D 5 GRAVEL BOLLOERS COBBLES Coarse I Fine Coarse I fl'.adium NOTES I. STATISTICAL DATA BASED ON SAMPLES RECOVERED tN 3 11 O.D. SAMPLER. 2. FOR TYPICAL GRADATION CURVES OF EACH STRATIGRAPHIC UNIT SEE FIGURE 6. 8 40 so eo 100 200 270 f r ~ I -~ .. --"-~ ' ~ r--~ ~ ..... ~ ..... '-·~'-r--' '~ . ~- i'-~a.. ~ II!.: " -~ ~- ~ ' "-· ~~ "~. ~- ~ r-.... !'.... ~~ ' I' ' .... ~ 1 ...... ~ ....... r-- 0.5 0.1 0.05 SAND I Fine WATANA RELICT CrtANNEL/BORROW SITE 0 COMPOSITE STRAT~GRAPI{!C UNIT G GRADATIONS SHEE·r 6 OF 6 0 ............. ! 1->. ~~ I ""' r-UPPB 1JM1L 10 I' r-. ~ ENv'EUDPE ......... ' 20 [~ ~ ' ., &> ' "!!a. . ... ~ ' ··~ ~'" ... < 40 ' ~· ~ 50 ' ... ~ ..... L s ·;.~ ~ ·. . iL"j('j "lli~ -i! :- ~ ~ .. ..... ' ~ "' ~ 70 " "" ""-·. l ' t eo "" "' ~ !:" ~ 90 .... ..... " ~ ..... i'---..... ""-.. t---- "" --0.01 QOOitOQ FINES Silt Sizes Jttay Sizes NUMBER OF POINTS= G? ~-""'""'--! FIGURE 8. 3 ! ~~~l~J I I I I I I I I I I I I I I I I I I I M 1- z ::::> 0 E/F :I: ·"' <i. a::: (!) \-G < a::: 1- Cl) G' 0 10 20 30 40 WATER CONTENT ~0/0 } c::..p,. _) M\N. I MEAN L MJX :!:J STANDARD . I DEVIATION ~ WATANA RELICT CHANNEL/BORROW SITE 0 COMPOSITE NATURAL MOISTURE DATA 50 FIGURE 8.4 t.!~MBER OF DATA POINTS 64 23 II 38 112 124 19 6 24 10 I ------------------------------------------------------------------------------ 1!111 --•• _, ------ - -.. -~ .. - -- 30 . -I • .. .~ cf!. 20 (f) w _J 0- :E <l (f) z - 1-15 z IJJ 1-z 0 0 IJJ 0:: :::> 1- !£! 10 0 :E I X / I • APPROXIMATE I DATAT/ • • • ,. • • • • • & • v • • 0 / • • • • • I • • X • • e • • J • .. • • "' ~ v X• • X. • • • • • • • X 0 • • • II' • • X • • • • • • .. ~ ., • x •• •X • • Cl X • • • • X.. • • 8 • • •• • • • • • • • 0 •• • .. y ... ... ,..... -• • r~ ·~· • ~· • •• . ~ . , :tf • a Xq .. . • • • -~ • x.x~, . .. ~~-• Q • • . .. 0 . \ " ..... • •• • • • • • • .. • • ,. . •a • • t • .. • • X>t • X ,_... / 25 A • 5 (POPULATION INCLUDES All RE?RESENTATIVE SAMPLES IN UNITS C,D,D',J,M,EANDF} • 1982 tjATA {N=226 SAMPLES FROM BORINGS) X PREVIOt!S DATA 0 I I 10 20 30 40 50 60 70 80 90 N=248 PERCENT PASSING #200 SIEVE IN SAMPLES ~A~~l~ 1 WATANA BORROW SITE D BORROW MATERIAL MOISTURE I GRADATION RELATIONSHIP FIGURE 8 5 ______________ .. ___ _ ' • c I FREQUENCY ., MAXfMUM MINIMUM MEAN °/o (0/o OF 4.8 °/o MOISTURE 29.1 °/o SAMPLES} I ii.6 I 40 1-I I I I I I . I I I I I GRAPH REPRESENTS 248 SAMPLES FROM AH-DI THROUGH AH-D30. (ALL BORING 30 -I DRIVE SAMPLES FOR WHICH MOISTURE I CONTENT WAS DETERMINED IN STRATIGRAPHf~ UNITS C THROUGH F ) . I I I . 20 ~ I . I I I 10 -~ I 1 I I 1 • I I I It I I I I I I I I I I 2 4 6 8 lO 12 14 16 18 20 22 24 26 28 30 NATURAL MOISTURE -We; (O/o) ' WATANA BORROW S\TE D f ! f ' BORROW MATERIAL MOISTURE FREQUENCY DISTRIBUTION • FIGURE 8.6 ------------~~~~------- 60 ~----~----~--------~----------~----~-------------~--------~----------T---------~· LEGEND X U.1 c z 50 NATURAL MOISTURE CONTENT-BORROW MATERIAL LOW PLASTICITY OR 11 LEAN"CLAY >-~30~-----+~~~~~--~-----------+----------r----~ (.) ~ (/) <( _j a. 10 ML 0 ML 8 OL 10 20 30 40 UQUIO LIMIT (.___....#1 ± ( <T ON ALL UNITS C THROUGH F RANGE AND MEANS OF ATTERBERG LiMITS ® MEAN VALUE OF SAMPLES FROM UNITS INDICATED BY DESIGNATED LETTER __..,. 50 PLASTIC OR ''FAT CLAYS a SILTS CH UPPER LIMIT OF PLASTI ALL UNITS ABOVE "G" INCLUSI JE RANGE OF ATTERBERG LIMITS (88 DATA POINTS) MEAN VALUES INCLUDE NON- PLASTIC 1 NON-VlSCOUS DATA POINTS. A SIGNIFICANT NUMBER OF SAMPL.ES HAVE LIQUID UMfT AND PLASTiCITY INDEX =0. i. •"! so 70 so FIGURE 8.7 ~-'-'·'-·~"-...... ,,..__ ' ------ TEST PERFORMED ON MATE~IAL PASSING , NO. 40 SIEVE IN ACCORDANCE WITH ~ ASTM 042~-66 (1972) AND 0424-59 0971) I (INCLUO~S ALL TESTS 1978-1982) --- - ------- ·------------------------------------------------------------------------~ ATTERBERG LIMITS TESTS STRATIGRAPHIC UNITS ABOVE UNIT E FIGURE 8.8 r·~---~ m -z C') ~Z-f E ~nom -f" CJ) 3:""'-f 0 o"tJ ITI otnrra en .:._::u NIYl""' l> !.>1<0 ' rn ::v r (1) ~ r Clzrra = 0 .. rTt ~f;o I~ N(")Z ~o )>:;uS: (/) :zol> ol>-t -z"' «> on~ ~ .t>fl'll> ~~r I I :':i :V (0 Ul:rl> (l) ID ~ N ~ i :::! G'l ...... (J) ~~ ~--~ -m G>:::o ::tltD l>f'11 -o;:.u :r:G') 0 r c-z~ :;:i@ (fj rrlr,1 l>ti.J) Z-1 ocn "Tl ,.. G) c :::0 fTI ()) . <0 ~:;:.;.;'''"'1 c:: = ; P.9 11 ~~" 0 ~ PLASTICITY INDEX OJ 0 .::. 0 "" 0 Cil 0 ~ 'f J I I I I I I I . I I I I ·I f I I I I I I I i I I · I ·1·++· I I I i I . I I I I I I +-f-.;!-+-+ I I I I ~-~ I I I I I t +,.+-f-'1 r 0 s; tu 0 0~ c:o ~ =i 01 0 Ol 0 (3 00 0 I I I I I I I I I I I I I I I I l-+H-++-t-+t-++-t-tam-.rffilt2++-H-< II I II t ltl:l,tllltitllll Hrrm==== =~~= ~==2 ~~7-: ~ f l ~ I I P I I I I , I · I I I I . I I I I I I I I f I I t ·I I I I I· f I I I I I I I I I I I I I I I I 1 A ++++~H·+ ... -+ I I I I I I I I ! I & + I I I I l I I l l· I I I I I I I I· I I I I !+++++++++++·+ 1 .. tt I It Ill !: ~tl:1=t+U.Wit\jJ:ttfE3tf ...j....4-~·-+:·· ~ .... . I 1·1·~ I~ f! I f'"r··H-++++++·i-1-+f-f-·1 !~1-,t·+n, J·m. ··t +,·+·++.·.··~""'" -H-. w. • •• ~·· ~-Mt··t· +- -+++·+-+-1--+·,.t-++~~ I ~1-t--++-+-++++++"t-+~t+·+-i·· ·· ·' ·· ++-t·+ t +- f+t ~ J±E tm±mn C') t+++"t-=t±# +-t++tJ: '·Hff~t~mrutt-rr: ~ftfi&fftfl __ + ·:;~lilflm.fi-HE ....,~+++f-+f...,L.l...l.-.L~ .. ...i....L.+-H .. ++··t··•··l··m~· ·+ ~ .. :+ .. ,, "t-f:t,t:t-:-t : t. 'lt·:·.t·.·· r.:b t,: .., . .,.,..,...1 .I.!. . . . . . ' . • . #J , t r~+ ~ :E t- ·+··: ~ ·,~: t "~ •w. ~ "' z 'U ~'~ . -r-r-r-H ~ , , ~ ~ +--+-·H-+++·t i ·;-rt-t:tn~i--· . .j.--.j..... +-f--~t ~!-t-11--l .. ~-i~ .'-j. -~-·1--~-:r-+:1. -~-.. P ~ E ·~n~ ~ .. ! .rt!?ttt+t+++ t + t ++.t 1 t + t j l 1 + 1 1 1 t t. ~ 1 tn , 1 t 1 t t . · · -~ ~ E ~ ttt! l rtt ! t l i l ~ l.l.ft.J ttu·~ l:Htl=lr t·t t ~0 • · t ~ . · 'l.t=r· ··t· t+",.t. t r ::u -~+-~+·-4 .. ·-+ ·+ .. ++ lii t· :··r+-i· T+t ·1· ~ '"~ +~ "t I t I I l i ! I I I I I I ~t-I I I I I t r I I f I· I I I ~t-t-t·t .. tfi··+ t·--+-···rt~,., . . . • ·+··t-·t·++· attlt tttttt ~:a , , 1h4 , . , ! m· .f-... t:·l· +E·· .. · .. +1· .. +·of' l-f . m· , -4-~· .. +··rt·!t±·-4· + . ..~ 1 :1. . 1 :rs1 t .... Lt ... T. t ... . . +t -~ + -t· + m. t" :f .. -t +~ .. ~ . f ·~ ' + v ·i-~tt-r+= ' +l t4-t·• ·t ··· ".j.' •·+ •f.-•H+•+-+· 4 t4-l•nf j ·+-+. •f" < f . + " ------------·-- I I I I I I I I I I I I I I I I I I I ---- ~ 0 2 60 50 20 10 i 1 '-·~ ·. . :. ~ ~ . ~. . I. .l(., • '• • -- l=L l.l .. L ~ . ;ME~~-t-1 1 .M ~ --- --.. - ..... ~ !\ tl :"'"to-1:.,1 [l l ~ I"" ,~, ir.'\ ill' ..II' ! ... " ~~ ~ 1,. i i t t 1 f 1'-~ .L -0 TEST PERFORMED ON MATERIAL PASSING NO. 40 SIEVE iN ACCORDANCE WITH ASTM D423 ·GG ( 197Z ) AND D424-59 (1971) 10 (HOLES TOO SHALLOW TO IDENTIFY STRATIGRAPHIC UNITT':. BELIEVED TO CONTAIN UNITS A THROUGH G) - II 20 30 ATTERBERG LIMITS TES'TS COE 11AP 11 SERIES AUGER PROBES (1978) ----- 60 70 80 FIGURE 8.10 -------------------- . ~ +4-1~-~~~~~~~~~~4-~·++~~++++~~~+++~~~+4~~+44-~~~~-~~~·r·~~ .. ~~~~ ~~~+}.·+~ .. ~~+4~~+-i~·~+~~~~~++~~~~~~~~~~4~~4-~~f--~+++~~+4~~+c~.~4·~~.~~~···~-~~·~4 I r 1-o !.;;! 40 l-++-ll-f-+-++-lr-+-+-t-1 ~f-++4-f-tf-.f-f..+-+-+-~+-+-+-?--+-+-+-+-~+--+-+-+-·f-4--4-i-~4--t-+-~4-4-l-++-t-t-of~-t-1-+-rll.:;:U~f..+·-1"·+·~r+-·+4-<+ .;.. 1 ..... ~'cf:.+pl X LLJ c z 10 0 TEST PERFORMED ON MATERIAL PASSING NO. 40 SIEVE IN ACCORDANCE WITH ASTM 0423 •66 (197.2) AND .0424-59 {l9"ll) (INCLUDES ALL TESTS 1978-1982.) 10 I • 30 40 LIQUID LIMIT 50 ATTERBERG LIMITS TESTS STRATIGRAPHIC UNITS BELOW BORROW MATERIALS 60 70 80 FIGURE 8.11 I I I .I I I I VI I I I I I I I I· I •• I . I 145 140 -..... 135 Q c, 134.2 .... ;I' .'>- i- (/) z w 0 >-130 a: 0 128.4 127.5 122.0 MIN j G5 ~ 2.60 NATURAL WATER CONTENT APPROX . MEAN RANGE OF 95 °/o DENSITY -t- 7.5 8.8 II. 6 °/o -X MAX. 29.1°/o 120 ~~~~L-L-~---L~--~---L--~~~~--~~~~ 2 4 NOTE: . MATERIAL PASSING :S/4 u SIEVE ( 7 TESTS-FIGURES 8.13-8.15) ASTM 0698 -78 METHOD C 6 8 10 WATER CONTENT (0/0 ) 12 14 16 INCLUDES ALL STANDARD PROCTOR DENSITY TEST$ PE.RFORMED TO DATE ON PROSPECTIVE BORROW MATERIAL WATANA BORROW ~ITE D RANGE OF STANDARD PROCTOR DENSITY TESTS STRATIGRAPHIC UNITS C THROUGH F FIGURE 8.12 I I I I I I I I I I I I I I I I I I I I 145 140 -~ 135 0. - ~ 133.3 en z w a ~ 130 a 126.6 125 12.0 ~ v ~~ 1---- \ ~ \ -= I\_. ~ \ 1\ I Y.\ ,;{ \ ~-' lr-95 °/o STANDARD PROCTOR DENSITY ,__ ____ +-_ r..s I I I G5 = 2.69 r I ~\ ZERO AIR VOIDS ' 1\ ~ --1\ 1-----~'---- ~ '--, ·""'- \ 2 4 6 / 8 10 12 14 16 WATER CONTENT (0/o) NOTE: MATERIAL PASSING 3/4 11 SIEVE LEGEND: (12 TEST PITS 1 10ENTIFIED AS UNITS uC11 THROUGH 11 F': UNDIFFERENTIATED) A COMPOSITE SAMPLE OF ~ COE TEST PITS~ AASHTO T-99 METHOD D (COE,I978) WATANA BORROW SITE D STANDARD PROCTOR DENSITY TEST COE COMPOSITE SAMPLE (1978) TPS-1 TPI4-2 TP9-1,2 8 3 TPI5-2 TPI0-1&2 TPI6-l&2 TP!~ -I TP 17-2 TPl2" l82 TP 18-1 TPJ3-I TP19-JS2 FlGURE 8.13 I I I I I I' I I I I I I I I I I I I I 140 ·\ --135 0 -...... -I I \ \ >- t- C/) 2 W· G5 = 2.60 (ASSUMED)_,.!'\ SAMPLE 82 - 74 ~1\~'1-!~--{--zERO AIR VOIDS Cl ~ 130 ~-+--+-~--~--~-+--~i'\-4\~~~-r--+--+--4-~~-4 o SAND LENS WITHIN -\ UNIT E/F~ k .._ I "'u /7'-!f'\\ !\_ V I \~ 1\,......_\ G5 = 2.65 ~~ SAMPLE 82-26 )w!l 1\ . r\ 125 J-.--+-+-~-+-~~~-+--+---\~f---r---Y-~-+--4---f---..f UNIT C vj/ ~ \ \ 95 °/o STANDARD 128.4 122.0 d 7·~ Y.F ~ 120 ~-L~~~~~--~~--~--~~--~~~.~~--~~ 2 4 6 8 10 12 14 16 WATER CONTENT (0/o} NOTE: LEGEND~ MATERIAL PASSING 3/4 11 SIEVE ASTM 0698 METHOD C 0 W82 .. 26 PIT 4 WATANA BORROW SITE D STANDARD PROCTOR DENS!TY TESTS SELECTED SANDY SAMPLES 8_ W82-74 (1982 ACRES) FIGURE 8.14 i I I I I I I I I I I I I I I_ I I I I I -------------------------~--·------------~----------~-------- I 145 140 -135 -(.) 0. 134.2 - >-ZERO AIR VOIDS f- en 132.1 z w 0 >-130 0: 0 127.5 125.5 125 ~-+--4---~~--~-~~-+--+--4~~~~~--~~ 1 8.0 8.8 2 4 6 8 10 12 14 16 WATER CONTENT (0/o) LEGEND NOTE: 0 W82-2 PIT 3 1 3a, 3b MATERIAL PASSJ~fG 3/4 11 SIEVE ASTM 0698 MET HOD C 6 WS2-30 0 W82-44 PIT 2. Q W82-91 WATANA BORROW SITE 0 STANDARD PROCTOR DENSITY TESTS STRATIGRAPHIC UNITS E a F FIGURE 8.15 I I I I I I I I I I .I I I I I I I I I I 145 140 137.7 I ~~+----+-G5 = 2. 71 ,_ ~--+-G 5 =2.75 ~ 135 ~-r--+-~~~~4-~~-t~~--+-~~-+--4---+-~ ~134.9 >- J- C/) z w 0 130.8 ------·-~--~ 130 ~-+--~~+---~~--~~+-~--~~+-~---r--~~ o 95 °/o MODI FlED PROCTOR DENSITY 128.2 125 ! t • I 6.0 6.6 ' 120 2 4 6 8 10 12 i4 16 WATER CONTENT (o/~ i\'OTE : LEGEND: K~ATERJAL PASSING 3/4 II SIEVE ASTM ;:55.7 METHOD C ·(1982 TEST) AASHTO T-180 METHOD 0 (1980 TEST) 8 W82-2 PIT 3,3A. 8 38 (1982) 0 W80-300 {1980) WATANA BORROW SITE 0 MODIFIED PROCTOR DENSITY TESTS STRATlGRAPHIC UNITS E a F FIGURE 8.16 I I I I I I I I I I I I I I I I I I I . 145 I ' I "' 140 ~ " ......... ..._ 135 () o..' - >- t- (/) z 11J 0 >-130 0:: 0 f ZERO AIR VOIDS ~ I \~=2.75. 125 vc 1\ I 1\ ~~ --+----1 127.8 ~ l v \ \ I 195 °/o MODIFIED I\ PROCTOR DENSlTY 1\ I \. ~---~-~---~----~ --~s---~--L~p:--)\-l 121.4 120 2 4 6 8 10 14 t8 WATER CONTENT (0/o) NOTE: LEGEND ---MATERIAL PASSING 3/4 11 SIEVE ASTM 01557-78 METHOD C 0 W 82.-2 PIT 5, 6 a 1 WA.TANA BORROW SITE 0 MODIFIED PROCTOR DENSITY TEST ·sTRATIGRAPHIC UNIT G FIGURE 8..17 I I I I I -I I I I I I I I I I I I I I I 8 ~ r... w I l'rl,224,000 "'+·· ! .. REFERENCES' BASE MAP FROM COE,1978 ~I" •2001 WATANA TOPOGRAPHY, SHEET 6 a H OF 2.6 ' R aM,1981-t''~400' DEVIL CANYON RESERVOIR MAPPING,FLIGHT 5 (6-S),MANUSCRIPT 2 COORDINATES IN FEET, ALASKA STATE PLANE { ZONIO: 4) 0 0 q "' If) l-- UI 0 0 0 0 "' ... w WATANA BORROW SITE E GEOLOGIC AND EXPLORATION MAP / ·"' / '\~ \? Fl.OOOPLAIN NOTES• I. TYPICAl.. SECTIONS AND PHOTOS SHOWN IN AAl,l982. \ 2. CONTOUR INTERVAL 25', TRACED AND/OR REDUCED FROM ~EFERENCED BASE MAPS. 3. ~SW" SEISMIC LINE LOCATIONS CORRECTED AS PER SaW ORIG!NALSURVEY NOTES, 139.0-81 LOCATIONS PER RaM SURVEYS 4. MATE;RIAL LIMITS EASED ON FIELD EXPLORATION, MAPPING AND AIR PHOTO INTERPRETATION. FINAL LIMITS OF SORROW MATERIALS SUBJECT TO RESULTS OF DESIGN INVESTIGATIONS. 5. BORROW LIMITS EXTEND TO $0UT'i SHORE OF RIVER, AND ADJOIN. B'JRROW SITE I I AAI, I982)0N WEST END.(FJGURE 8.19) 6. tl\ :>LORAT.I!. ~ LOGS ANO SEISMIC LINE SECTI t~S SHOWN IN AAX,I982. •TP·E3 I Jl, AAI BACKHOE TEST PIT TP·RI3 GEOPHYSICAL SURVEYS= 8sw-l2 SEISMIC REFRACTION SURVEY TURNING OR END POINT SW-12 1978, SHANNON a WILSON SLSO-S 1980-81, WOOOWARo~cLYDE CONSULTANTS CONTACTS: ----SORROW SITE LIMIT ----·· BEDROCK EXPOSURE, APPROXIMATE: t.~).AJT ----SURFICIAL DEPOSITS, APPROXIMATE \Lt\\IT OTHER: • ' • • • •" TERRACE, HATCHURES ON FRONTAl.. $il..OPE 0 400 600 FEET SCALE !""= ·-= . : -·· FIGURE 8.18 I I I I I I I I I I I I I I I I I I I 1 li 3,2.!0' 000 c •' 0 0 0 ' ;/1 0 q \ ' t::: c -.;., ~ ~ .... w ~; WATANA BORROW SITE I GEOLOGIC AND EXPLORATION MAP LEGEND LITHOLOGy: I I SURFICIAL OE;POUITS D 0' q c 0 '~ •;JJ; BOREHOLES AND TEST PITS: BTP·RB 19BI,AAI TEST PITG AN.D TREI\I:::HES GEOPHYSICAL SURVEYS: SEISMIC REFRA!;fi(JN SURVEY END OR &.SLBI·B TuRNING POiNT~ I!J!.ll, WOODWARD-CLYDE CONSULTANTS CONTACTS: ---BORROW SITE l.IMI"'' -----BEDROCK ::XPOS\.!FU!,APPROXIMATE LIMIT ---SllRFICIAl:DEPOSilS, APPROXIMATE LIMIT OTHER; = TERRACE,. HATCHURES ON FRONTAL SLOPE - o· 0 -.::, r,.,_''l- t; ~,j NOTES I. CONTOUR iNTERVAL 100~ TRACED FROM t"'•;t~o• ENLA.RGEMB...,. Of REFERENCED eASE MAP. 2. BORROW MATERIAL IDENTIFIED IS RIVER GRii.V'Et. AND SAND DEPOSITS,INCLUDI~lG ACTIVE Fl.~OPLAIN,MIO RIVER BARS, AND TERRACES NEAR RIVERUc\iEL. 3.MATERIAL LIMITS BASED ON FIELD MA~ ANDAIR PHOTC: INTERPRETATION. FINAL MAPPED LIMITS ~ SORROW SITE SUBJECT TJ RESULTS OF DESIGN lN\~TlGATIONS. 4 ENTIRE BORROW SITE AS DRAWN LIES WITH~~ ~ROPOSED OEV!;.. CANYON RESERVOIR LIMITS. LOCAL DEPO~~ ARE INFERRED TO CONTINUE UP SLOPE BEYOND LIMITS $!OWN. 5. EXPLORATION LOGS AND SEISMIC LINE OA't.;\, ARE SHOWN ~~ AAI, 19S2. 6. EASTERN LIMIT OF SITE COINCIDES· WITH~WNSTREAIA LIMIT Of BORROW SITE E, 7. TEST PIT LOCATIONS APPROXIMATE. 8. TEST PITS R -12. THRU 14 SHOWN IN AAI, \~2, SCALE 0~~~1~0~00~~2~000FfET FIGURE 8.19 1 I I I I 0:: w 1- _J 0:: I w a. (J) w ..J 0 I :E _J -' ~ >- I t: z -' <r ~ -' I <( z z 0 j:::: I u ::> a w 0: 1 u I. 0:: I I I I I I I I I r 600 ~- • AGGREGATE CONSIDEHED NON-DELETERIOUS • • AGGREGATE POTENTIALLY DELETERIOUS o~----~--~_.~----~--~--._~----~---.1~~'--'-----· 2.5 5.0 7.5 10 25 50 75 100 250 500 750 1000 2500 Sc -DISSOLVED SILICA (MILLIMOLES PER LITER) NOTES·. REFERENCE; ASTM C 289-81 FOR TEST SAMPLE DESCRIPTIONS SEE TABLE 8.2. WATANA BORROW SITE E AGGREGATE REACTIVITY TEST DATA FIGURE 8.20 / I r I I I I I I I I I I I I I I I I I I TEMPERATURE ("CI -3 -2 -1 0 I a 3 212.7.5 0 I I. ~ 21P.O 201-. roBOTTOM l 2.100 § OF PVC j: e: IIJ W40 IIJ e: ..J t 0 i ~2080 X I i= ~ 60 ~ Ill X ..J li: I 1&12.060 ~ 80 t 2040 t-STICK UP-0.0 FEET I (OEC.,I9BI) tool AH·HI TEMPERATURE (•c) 2 -3~ __ _:-a;_ __ ~-~~-----lo~----.-'----~--~ 2.064.5 0 • ~ 2osa \ 1 ' \ ! ~BOTTOM ! 20 2040 l OF PVC ; -~ ~ 5 ~ ~ 2000 t w •t ~ 80 1990 . • STICK UP·5.0 Ft:ET (JAN..,I982) ___ ...~_ _________ ---100 L-~-----~~ 2iSa."t '~ 2'90 2.160 j: 1&1 !OJ .!:!: 5 2140 ~ > L IIJ ..J w 2120 2.100 -3 0 -20 ... w IIJ ~ z ~ 0 c60 ~ Is.! Q AH-H4 TEMPERATURE !-C) ·I 0 i STICK UP-3.5 FEET (JAN., 1982) ' BOTTOM :oF PVC AH-H7 2 3 ~~ ( .. ~1940 t:i IIJ 1&.. St92o i= ~ bJ u:l 1900 1880 2.186.2 2.180 2093.5 2080 t: 2060 IIJ IIJ !:!; z ~ 2040 ~ IIJ ..J w 2020 2.000 t: ll.l w ~ w ...1 0 :r z 3: STICK Uf'· 4.0 FEET L~{~J~AN~-~,1~9~82.~)~--------L---------~ 100 100 -3 0 20 AH-H2 BOTTOM OF PVC STICK UP-4.0 FEET (JAN.,I932) ______ L _________ _ AH-H5 8 60 i!= a. w a STICK UP· 3.0 FEET (JAN.,I982.l ---.~L-.. -. ---· ·-!00 '----~ AH-H8 WATANA BORROW SITE H THERMISTOR DATA TEMPER~TURE (•C) ·I 0 I :h OFPVC I I ! 80 I I STICK UP-4.0 FEET L~(~JA~H~-~,1~98~2~)----------L------------------100 ~H-H3 LEGEND SHOWN ON FIGURE 5.21. -3 ·2 ., 0 SCALE 1 I I I I ! I I I I 27 2.8 29 ~ 31 32 33 ~ ~ ~ M FlGURES.Zt 2 ~"C I I I. 35 36 ~ "f' '~ • I I I I I I I I I I I I I I I I I I 9 -RESULTS OF GEOTECHNICAL INVESTIGATIONS -DEVIL CANYON DAMSITE 9.1 -Introduction · The results cf the on-going studies at the Devil Canyon Damsite during the summer of 1982 are presented in this section. The three principal subsections are: Subsection 9.1: Materials Properties Subsection 9.2: Groundwater Regime Subsection 9.3:· Permafrost Regime The work related to the Devil Canyon damsite in the 1982 summer program involved completion of the laboratory testing of quarry and concrete aggregate materials begun in 1981, and reading of borehole instrumenta- tion installed in 1980-81 for groundwater and permafrost regimes at the damsite. 9.2 -Material PrqQerties (a) Borrow Site G The 1980-81 exploration program had obtained test trench samples in Borrow Site G, which were classified and then submitted for testing (1). Because this area was designated as the source for all concrete aggregate, grout sand and filter Jravels and sands, the suitabi 1 ity of the materials for use i t1 cot.crete and as granu- lar fill was tested. Additional complete concrete mix design and mortar bar tests were not deemed necessary until final design, since previous tests (36, 37) had shown that this source could produce a suitable mix design~ The results of the general aggregate suitability tests ~how that the aggregate readily meets the ASTM, COE and USBR generic stand- ards (Table 9.l)o All factors were well within the limits for general construction (non-architectural) use in concr~te, and the low absorption and high abrasion resistance indicate probable suitability for general aggregate use in roads, filters, and rela- ted uses. The aggregate testing for freeze-thaw durability shows only mode- rate losses up to 150 cytles (Table 9s2). While there is no gene- rally accepted standards, 1 asses of· not more than 5 percent for 200 cycles is frequently considered. a reasonable limit for cold regions use. Preliminary laboratory ana\~ ";is of various material types within Borrm'l Site G show the alluvial material near river level to have a more favorable petrographic composition and quality than the materia 1 in the upper terrace. This. could be because the 1 ower bar repres~nts more worn, abrased materials, and hence has had much of the poor quality material removed naturally. 9-1 0 0 The materials from the upper terrace Zone I (1} exhibi~.=-generally poorer quality particles, but fewer potentially reactivf:: .:;ilicates such as chert and glossy volcanics such as dacites an<! andesites than the lower terrace.. This, material also showed poorer perfor- mance in sodium sulfate soundness and absorption testing, although the differences were not critical (Table 9.1). Because the lower, near-river level terrace (Zone I, Figure 7.22) Reference (1) comprises the majority of the proven and inferred reserves, and apparently has higher quality freeze-thaw perfor- mance, chemical reactivity tests (Table 9.3) were run on this material to determine if the free silicates identified by.the USBR testing would pose a problem in mix design. While the USBR tests showed very suitable performance on a 6 mpnth test mix series, additional samples were tested during 1981-82 using the chemical test method of reduction of alkalinity in silica solutions The test data indicates that the aggregate is well within the normally accepted range of values for aggregate and is unlikely to have an adverse silicate reaction (Figure 9.1). On the basis of these tests, physical examination of the aggre- gate, and working within the estii,Jting assumption that signifi- cant aggregate processing wi 11 be performed on the material to reduce the poor quality fraction, it is felt that this borrow source is fully suitable for all uses at the damsite. However design level invt;st_igation will require a systematic de- velopment of a mix design with high freeze-thaw durability using special screening, w(lshing, and drum rolling processing as may be necessary for construction. In addition, testing should include using a variety of material types found throughout Borrow Site G. It is also recommended that detailed drilling be conducted to depth over the ent1re borrow site. (b) Quarry Site K Quarry Site K has been identified at Devil Canyon as a potential source of quarry rock (1). To confirm the suitability of the rock as construction material, a 150 cycle freeze-thaw test was perfor- med. The results~ of the test showed an 8 percent loss at 150 cycles. This unusually high loss, which is in contrast to the test results obtained from the same rock type in Quarry Site A (see Section 8.1) 1 may be due to the fact that the samples were hand-s amp 1 es from the surface that may have been weathered and severely mictofracturedo To confirm these results additional detailed testing will be required on 11 fresh 11 samples during the design level investigation. 9-2 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 9.3 -Ground Water Regime The groundwater readings during 1982 cant~ nued to. show a seasona 1 fluctuation in the two north abutme~t holes (BH-1 and BH-2), with the level in BH-1 fluctuating from about 50 to 150 vertical feet belo\tJ the surface, and BH-2 showing water levels equal to or slightly exceeding the collar elevation of the hole. Artesian flow has been observed occassionally at the hole. Previous readings of BH-4 (1) had, as would be expected from its proximity to the lake, reflected only a few feet_ of annual variation from mean lake level. The most ~ecent readings of BH-4 indicate the pneumatic piezometer is defective and will have to be replaced. 9.4 -Permafrost Regime The 1982 thermistor readings in BH-1, BH-2 and BH-3 (Figure 9.2) con- firm the previous data presented in the 1980-81 Geotechnical Report (1). Complete annual amplitude envelopes are shown in Figure 9o3. The depth of annual frost penetration in bedrock appears to be about 10 to 18 feet, with the deepest frost penetration being in May to June. Depth to annual amplitude is deep, ranging from 40 to 100 feet. As noted in the 1980-,81 Geotechnical Report (1), it appears that the instrumentation installed in BH-4 is defective with failure slowly pro- gressing up the string in a constant, uniform progression. Additional i nstr umentat ion wi 11 be required in this area to determine the subsur- face thermal conditions. .-; 9-3 ------~------------ .... Sodium Sulfate Soundness ASTM C-88 (1976) % Loss Sample Number pepth C.A. F.A. TT K-6 & 0-58.1' 2.3 3.7 TT K-19 11 K-21 & 0-30.0' 2.5 5.1 TT K-93 (USBR) (AAI) .. ;T G-1-2 5.0 TT G-1-3 16.0 1.0 TT G-1-4 25.5 TT G-1-5 37.0 TT.-G-2-3 6.5 TT G-2-4 8.0 TT G-2-5 15.0 0.6 TT G-2-8 18.0 TT G-2-9 24.5 ASTM l1) & COE (ZJ Recommended Limits 12 12 . USSR (3) Recommended Limits 10 8 " TABLE 9.1 DEVIL CANYON BORROW SITE G AGGREGATE SUITABILITY TEST DATA % Absorption % Lightweight Particles ASTM ASTM ASTM C-123 (1975) . C127 C128 (1980) (1979) C.A. F.A. C.A F.A. 0.3-0.8 not o.o 0.7 run 0.5-0.9 not o.o 0.9 run 0.62 3.2 0.0 not run o. 6 3.7 o.o not run 5% 3 3 10% 2 2 Specific Gravity L.A. Abr as T .. "''" ~-;i ASTM C-131 ~1981) ASTM ASTM (500 revolu~ions) C127 C128 (1980) (1979) C.A. F.A. % Loss Gra,..:!i ng 2. 74. 2.71 17.6 ~ . ' 2.75-2.71 16.7 rt· r~ 2.82 2.76 2.71 18 P\ 2.81 2.71 16 ~\ 2.40 2.40 50 A 2.60 2.60 40 A TABLE 9.2 DEVIL CANYON BORROW MATERIALS FREEZE-THAW DURABILITY TEST DATA SAMPLE SAMPLE Aggregate Cumu 1 ati ve Loss ~% of Weight} {1} {2} 80 Cycles 115 Cycles 150 Cycles NUMBER DEPTH 35 Cycles 40 Cycles W80-82 Outcrop, 1.1 7.2 8.0 ., (Quarry K) Surface TT-G1 0-37 1 1.3 2.0 2.3 2.5 (Borrow G) TT-G2 0-24.5' 1 .. 5 2. 0 2.1 2.3 28 Day # Cycles to 25% w/c Ratio % Air Strength :..oss {3) TT-K-6 & 0-58.1' 0.51 6.2 4280 psi 515 TT-K-19 (SUBR) TT-K-21 & 0-30 .. 0' 0.51 6.2 3860 psi 390 TT-K-93 Notes: {1) (AASHTO, 1978) Tl03-78 Method A, Course Aggregate & Ledgework Samples (2) Tests performed by R&M Consultants ( 3) USBR Method, simi 1 ar to AS fM C-227 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I~ C0~1BINEO fABLE 9 .. 3 DEVIL CANYON BORROW MATERIALS POTENTIAL REACTIVI.,.. QF AGGREGATES-TEST DATA (1) Sit.VE SIZE SAMPLE SITE PASSING RETAINED Rc Sc RESULTS TT-G1 TT-G2 TT-G2 TT-G2 TT-G2 TT-G2 TT-G2 TT-G2 Notes: 3/8 11 #4 180 28.2 Innocuous 3/8 11 #4 211 72.9 Innocuous 3/8 11 #4 162 67.3 Innocuous 1/2 11 3/8" 220 39 .. 9 Innocuous· 3/4" 1/2 11 158 61.3. Innocuous I 1" 3/4 .. 242 31.0 Innocuous 1-1/2 11 r·~ 145 30.5 Innocuous 2" 1-1/2" 89 41 .. 5 Innocuous Rc =Reduction in Alkilinity (millimoles/liter) Sc = Concent1·ation of Si02 (millimoles/liter) in the original filtratE (1) ASTM G-209 (1981) (2) Tests performed by Chemical & Geological Laboratories of Alaska, . Ir.~., under direction of ·.&M Consulta·nts. TABLE 9 .. 4 DEVIL CANYON BORROW SITE G ESTIMATED BORROW MATERIAL AVAILABILITY MATERIAL MATERIAL 11 KI'IOWN 11 TYPE ZONES (1) RESERVES High quality gravels la/Ia ?1. Ib 1 .. 1 me·· and sandy gravels Cobbly & bouldery III 0.3 gravels, (believed to be high quality} Upper terrace gravelly sands, marginal to II 0.5 submarginal quality Talus deposits, m·inor IV 0.0 Cheechako Creek reworking Miscellaneous Upper Saddle Dam o.o Level Terraces (thin Area overburden zones unexplored) TOTALS 1 Q mcv • _, JU J ANTICIPATED PROJECT DEMAND -2.0 -2.1 mcy Reference (1) 1- I I I I TOTAL 11 KNOWN" + 11 INFERRED" RESERVES 3.1 mcy · I 1.1 I 2.0 I 0.05 I (0.9) I I 7.2 mcy I I I .,. I I I I I I I I I CJ:: w t: .J I CJ:: w (L (I) w .J 0 I ::E :i .J ::E I >-..... z .J <.[ ~ .J I <( z -z 0 I ..... u ::::::> 0 w cr I I u cr I I I I I I < I I f " I 700~------------~----------------------·--------------~ AGGREGATE CONSIDERED NON-DELETERIOUS • e • • • • •• AGGREGATE POTENTIALLY DELETERIOUS 0 ----------~_.~----~--~--._~----~--~~~----~ I 2.5 5.0 7.5 10 25 50 75 100 250 500 750 1000 2500 Sc -DISSOLVED SILICA ( MILLIMOLES PER LITER) NOTES: REFERENCE; ASTM C 289-81 FOR Tt:ST SAMPLE DESCRIPTIONS SEE TABLE 9.2. DEVIL CANYON BORROW SITE G AGGREGATE REACTIVITY TEST DATA FIGURE 9.1 l ; • I I I I I I I I I I I I I I I I I I N3,2.2!,000 N3,224,000 REFERENCE~ .eASE. MAP FROM R & M,t981-l~• 200' DEVIL CANYON TOPOGRAPHY ., COORDINATES IN FEET, ALASKA STATE PLANE !ZONE 4) DIVERSION tNLE;T COFFERDAM ' . . . " . I • _.. •' :,'• . --·. . . LEGEND ~ iNSTRUMEifi'ED DIAMOND CORE BORING, HORIZONTAL BH"l PROJEC1101~S AS SHOWN. NOTES 1 <;EOLOGIC SECTIONS AND LOCATION MAPS SHOW:NG EXPLORA11C."t DETAILS SHOWN iN 1980-81 GEOTECHNICAL R:E"PORT,AAI. 2 CONTOUR INTERVAL 50'. TRACt:D fROM REFER~EO BASE MAE" 0 ~ SCALE L_ ... 5 400 FEET FIGURE 9.2. I I I I _I I I I I I I I I I I. -5 -4 -3 -2 1413.7 0 1402.8 STICK UP·O.O FEET {19811 1400 DIP-67• 1380 40 1360 1340 eo 1320 }- Ul ti 1300 ~ 120 ILl w ... ...J 0 z :r 0 z ~ 1280 3: 0 0 Ul ..J :I: w li: 160 1260 w 0 1240 200 1220 1200 240 1180 1160 L 280 LEGEND LITHOLOGY: ~ GROUND SURFACE ~ TOP OF ROCK BOREHOLES: -I TEMPERATURE ("C) 0 I 4 5 1213.4 1211.7 1200 1180 1160 1140 1120 1-w w IL 1100 z 0 ~ > ~lOBO ILl 1060 1040 102.0 1 ( j l I 1000 tBOTTOM OF i STRING 9SO BH-J NOTES l LOCATION Of HOLES SHOWN ON FIGURE 9.2. 2, THERMISTOR STRIIlGS MANUFACTURED BY INSTRUMENTATION SERVICES IN FAIRBANKS,ALASKA. AH BH AUGER HOLE! · . ACRES AMERICAN lt-ICORPORATED 3. BORINGS ARE INSTRUMENTED WITH PERMANENT MULTI-POINT THERMISTOR STRINGS, WITH TWO THERMISTORS AT EACH READING POINT. DATA FOR TWO POINTS IS AVERAGED. BORE HOLE w~ 0 40 eo }- ILl ::: 120 w ...J 0 X z ·:s: 0 0 X li: 160 ILl 0 200 240 2.80 DATA SYMBOLS: «: THERMISTOR READOUT BOXES MANUFACTURED BY KEITHLEY(I72A) AND FLUKE, USED FOR 1980 THROUGH 1982 aEADINGS. ENVELOPE SHOWING RANGE OF OBSERVED TEMPERATURES OBSERVED ACTIVE ZCINE (MAXIMUM DEPTH OF ANNUAL FREE1!NG/T4AWING) ..__~·--DEPTH OF ZERO ANNUAL AMPLITUDE 5. AUGER HOLES AH·GII THRU AH-G14 CONTAIN THERMISTOR PROBES, BUT NO DATA WAS OBTAINED. TEMPERATURE I • C) -4 •3 -2 -1 ' () I STICK UP-o,o FEET (1981) DIP -so• ~BOTTOM OF STRING ,__,....,.... --... ·-~-... ...._._._,.. . ···-··..,-<--· ----·---~--~------~--~ ......... ,._._-.~~----,.. BH-2 DEVIL CANYON DAMSITE THERMISTOR DATA 2 3 4 5 -s -4 1352.6 0 TEMPERATURE (•C) -2 •I 0 I 2 3 1346.5 1340 132.0 40 1300 l l l 80 I 1280 J PROGRESSIVELY DECREASIN\t ! TEMPERATURE REACINGS \ j IN THIS RANGE -1 F -I 1260 l 1- ILl 1-::: 120 UJ lf 12-40 lll ..J 0 z X 0 ~ z 3: 0 ~ 1220 0 :I: lll li: 160 lll 0 1201) - 1 tao 200 ! l HIGHLY VARIABLE REAO!NSS BELOW THIS POINT-APPARENT THERMISTOR FAILURE 1160 240 1140 ; BOTTOM OF STRING ll20t 2.80 ····~~----.... -- BH-4 -:; ~z -I 0 i . < "'"' . .,.... -" SCALE I I I I I I I I t ! I <7 <a 29 30 31 32 33 34 35 36 :'r'"F l FIGURE 9.3 • I I I I I I I I I I I I I I I I I I I REFERENCES 1. Acres American Incorporated, Susitna Hydroelectric Project, 1980-81 Geotechnical Report, 1982. 2c Acres American Incorporated, Susitna Hydroelectric Project; Feasi- bility Report, 1982. 3. Acres American Incorporated, Susitna Hydroelectric Project~ Supple- ment to Feasibi1ity Report, 1982. 4. American Society for Testing Materials, 1981 Annual Book of ASTM Standards, Parts 14 and 19, 1981. 5. American Association of State Highway and Transportation Officials, 12th ed., Standard Speci fi cations for Transportation nateri al s and Methods of Sampling and Testing, Part II, July 1978. 6. Billings, M. P., Structural Geolom:, Prentice-Hall Inc., New Jersey, pp. 108-114, 1962. . 7. Chapin, T., 11 The Nelchina-Susitna Region, Alas~a,t• U.s. Geologi- cal Survey Bulletin 668, 1918. 8. Csejtey, .B., Jr., 11 Tectonic Implications of a Late Paleozoic Volcanic Arc in the Talkeetna Mountains, Southcentral Alaska," Geology, Vol. 4, No. 1, 1976. 9. Csejtey, B., Jr., 11 The Denali Fault of Southern Alaska: The Case for Minor Rather than Major Di spl acement 1 ' s Transactions American Geophysical Union, Vol. 61L Na. 46, p 1114. 10. Csejtey, ~.,Jr., Foster, H. L., and Nokleberg, W. J., ncretaceous 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., Silberling, N. J., Dean, R .. M., Morris, M. S., Lanphere, M. A., Smith, J. G., and ~-ilberman, M. L., "Reconnaissance Geologic Hap 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 Regort 78-558A, 62 p. 1978. 12. Dames & Moore Inco, Subsurface GeoQhysical Exploration -Proposed Watana Damsite on the Susitna River, Alaska, Department of the Army, Contract Number DACH-76-C-0004, 1975 .. REFERENCES (Continued) 13. Detterman, R. L., Plafker, G., rludson, T., Tysdal, R. G., and Pavoni, N., "Surface Geology and Holocene Breaks Along the Susitna Segment of the Castle Mountain Fault, Al a3ka 11 , U. s. Geological Survey, Miscellaneous Field Studies Map NF-618, 1974. 14. Gedney, L. and Shapiro, L., Structural Lineaments, Seismicity and Geology of the Talkeetna Mountains Area, .~laska, Geophysical Institute, University of. Alaska, prepared for U. S. Army Corps of Engineers, 1975. 15.. Johnston, G. H .. , ( ed. ) , Permafrost _l!!ir~ neeri..!!£L Design and Construction, John Wi 1 ey and Sons, 1981. 16. Jones, n. L., Si 1 berl ing, N. J., Csejtey, B., Jr., Nelson, W. H. and Bloome, C. D., "Age and Structural Significance of the Chulitna Ophiolite and Adjoining Rocks, Socthcentral Alaska 11 , U .. S. Geological Survey, Professional Paper !!21-AJ) 1978. 17. Kachadoorian, R., 11 Geology c~~ the Devil Car.yon Damsite, Alaska'', U. S. Geological Survey Report to U. S. Bureau of Reclama- tion, 1958. 18. Karlstrom, T. N. V., "Quaternary Geology of the Kenai Lowland and Glacial History of the Cook Inlet Region, Alaska", 1!.!_h Geological Survey, Profe~siona1 Paper 443, 1964. 19. NPAS (North Pacific Aerial Surveys, Inc.), Control Survey Manu- scripts for R&M Consultants, 1981. 20. Pewe, T. L., "Quaternary Geology of Alaska", u. S. Geological Survey, Professional Paper 835, 1975. 21 .. R & M Consultants, Aerial Topographic Map of Devil Canyon Reser- voir, Scale 1 inch = 400 feet, 1981. 22. R & M Consultants, Devi 1 Can~on Climate Data, April 1980 through September, 1982, 1982. 23. R & M Consultants, Watana Climate Data, lLeptember~ 1982, 1982. September, 1980 throu9h 24. Richter', D. H. and Jones, D. L., 11 The Structure and Stratigraphy of Eastern Alaska Range, Alaska 11 , American Association of Petroleum Geologists, Memoir 19, pp. 408-410, 1973. 25. Shannon & Wi 1 son·, Inc., Se"\ smi c Refraction Survey, Susitna Hydroelectric Project, Watan~ and Devil Canyon Damsites, 1978. I I li I I I I I I I I I I 'I I I I I I I I I I I I I I I 1- I I I I I I REFERENCES (Continued) 26. Travis, R. 8 .. , 11 Cl assification of Rocks 11 , Quarterly of the Colorado School of Mines, Vol. 50, No. 1, 1955. 27. U.S. Army Corps of Engineers, Hydroelectric Power and Related Purposes, Upper Susitna River Basin, Southcentral Railbelt Area, Alaska, Interim and Final Feasibility Reports, 1975 and 1978. 28. u.S. Art11Y Corps of Engineers, f.etrographi c Examination of Ledge Rock, Report Series Numbers 1 and 5 ( 78/138 and 78/207), Missouri River Division, Omaha, Nebraska, 1978. 29. u.s. Art11Y. Corps of Engineers, Susitna Project Geology Field and Survey Books, Numbers 1 through 28, unpub ~ i shed, 1978. 30. U.S. Arrry Corps of Engineers, Susitna Pro·ect~ Re ort of Tests on NX Rock Cores for Talkeetna and Watana Sources 78-C-305 , North Pacific Division Materials Laboratory, Troutdale, Ore- gon, 1978. · 31e U.S .. Arrry Corps of Engineers, Standard Practice for Concrete, EM 1110-2-2000, 1973. 32. u.s. ArmY Corps of Engineers, Subsurface Exploration and Sampling of Soil for Civil Engineering Purposes, Waterways Experiment Station, 1949. 33. U~S. Bureau of Reclamation, Concrete Manual, 8th ed., 1981. 34. u.s. Burea1 of Reclamation, Design-of Gravity Dams, Appendix H, 1976. 35. u.s. Bureau of Reclamation, 11 Engineering Geology Report, Feasibil- ity Stage, Devil Canyon Dam, Devil Canyon Project 11 , Alaska Geologic Report No. 7, 1960. 36. u.s. Bureau of Reclamation, "Laboratory Tests On Cor-N ~--! gate from Devil Canyon Damsite, Al aska't, Concret _ Report C-932, 1959. 1\ggre- ::tory 37. U.Se Bureau of Reclamation, 11 Laboratory Tests of Foundac..on Rock Cores from Devil Canyon Damsite, Devil Canyon Project - A1 ask a", Concrete Laboratory Report C-93~, 1960. 38o Van Eysinga, FcW.B., Geologic Time Table, 3rd Edition, Elsevier Scientific Publishing Co.!t Amsterdam, 1975. 39. Woodward-Clyde Consultants, Final Report -Susitna Hydroelectric Proje~t, Seismic Refraction Survey.!.. 1980. REFeRENCES (Continued) 40. Woodward-Clyde Consultants, Interim Report on Seismic Studies for Susitna Hydroelectric Proiect, 1980. 41. Woodward--Clyde Consultants, Final Report -Susitna Hydroelectric Project. Seismic Refraction Surveys, 1981. 42. Woodward-Clyde Consultants, Final Report on Sei s.m..:!.!-:_ Studies for Susitna Hydroelectric Project, 1982. 43. \~oodward -Clyde Consultants, Susitna Hydroelectric Pr_gject~ei smi c Refraction Surveys, 1982. I I I I I I I I I I I I I I I I I I I