HomeMy WebLinkAboutSnettisham Project Alaska First Stage Development 1973,------
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NETTISHAIVl PROJtCJ
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IRST
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.'
DECEMBER
.l' ,-4'·"."5~,H!ty'3
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U.S. ARMY ENGINEER DISTRICT,ALASK
CORPS OF ENGINEERS
, , ,
,;lPt Y TO
~.TTENrION Of
DEPARTMENT OF THE ARMY
ALASKA DISTRICT. CORPS OF ENGINEERS
P.O. E,OX 7002
AN(~"iOHA(.,,'. AI A'":-)KA ',','-,I<}
NPAEN-CW 28 Decelilber 1973
SUBJECT: Snettisham Project, Alaska -Design Memorandum No. 23, Crater
Lake Plan of Development
Division Engineer, North Pacific
ATTN: NPDEN-TE
1. Transmitted under separate cover for your review and approva; are
copies one through eight of subject design memo.
2. Comments and recommendations made during the 19-20 June 1973 Design
Memorandum review conference have been incorporated into the text and
plates. The suggested alternative made during the conference has been
reviewed with Mr. Gr~ner, Norwegian consultant, and his comments have
been incorporated into the text.
3. No additional design memoranda with the exception of Design Men~ No.
24, "Underground Powerhouse" are planned to be submitted. Letter reports
covering hydraulic design computations for final design of the waten'Jays
and additional geologic explorations will be submitted for review. In-
dividual design analysis will be submitted for Supply contracts and
remaining features to be included in the construction contract. This
office is proceeding with the design as indicated in the design dnd
construction schedule included in the Design Me~ndum.
1 Inc1 (oct)
as (fwd sep)
Ld -/ CHARLES A. DEBELIUS
" ~~lonel, C9fps of Engi
~ s tri.ct--fngi neer
eers
No.
1.
2.
3.
4.
5.
Subject
HYDROLOGY
HYDROPOIlliR CAPAC ITY
SNETTISHAM PROJECT? ALASKA
Schedule 0: Design Memorandums
SELECTION OF PLAN OF DEVELOPMENT
Revised
PRELIMINARY MASTER PLfu~
ACCESS AND CONSTRUCTION FACILITIES
Revised
SUPPLEMENT NO. 1
6. DELETED
7. GENERAL DESIGN MEMORANDlTM
SUPPLEMENT NO.1, Concrete Aggregate Investigation
8. PRELIMINARY DESIGN REPORT ON POWERHOUSE
Revised
9. TRANSMISSION FACILITIES
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
2l.
22.
23.
24.
25.
SUPPLEMENT NO.1, Direct Current Transmission
SUPPLEMENT NO.2, Direct Current Transmission
SUPPLEMENT NO.3, Juneau Substation Auto-
transformers
SUPPLEMENT NO.4, Taku Inlet Submarine C~lbe
SUPPLEMENT NO.5, Permanent Communications,
SUPPLEHENT NOo 6, Juneau Substation
SUPPLEMENT NO.7, Suspension Insulator
SUPPLEMENT NO.8, Transmission Line Structures
SUPPLEMENT NO.8, Transmission Line Construction
SUPPLE}1"JmT NO. 10, Relocation of Power1ine
Facilities for Juneau Substation
POWER TUNNEL, SURGE TANK & PENSTOCK
SUPPLEMENT NO. 1
REAL ESTATE
DELETED
DAM, SPILLWAY & INTAKE STRUCTURE
SUPPLEMENT NO. 1
PERMANENT OPERATING EQUIPMENT
BUILDINGS, GROUNDS & UTILITIES
PLAN OF DIVERSION
DELETED
POWERHOUSE PENSTOCK BIFURCATION
POWERHOUSE ARCHITECTURAL DESIGN ~
POWERHOUSE STRUCTURAL DESIGN
POWERHOUSE MECHANICAL DESIGN
POWERHOUSE ELECTRICAL EQUIPMENT
CRATER LAKE PLAN OF DEVELOPMENT
POWERHOUSE DESIGN REPORT
MECHANICAl., ELECTRICAL EQUIPMENT
Date
15 October 1964
31 October 1964
22 January 1965
7 May 1965
22 April 1965
26 November 1965
29 April 1966
6 March 1967
13 November 1965
14 September 1967
29 August 1966
29 June 1967
23 December 1966
19 January 1968
10 February 1969
20 August 1970
3 September 1970
22 September 1970
24 February 1971
30 December 1970
12 February 1971
17 June 1971
11 August 1971
9 September 1966
27 May 1968
27 Harch 1967
30 January 1967
24 September 1971
29 March 1972
11 May 1967
22 July 1966
19 September 1967
13 December 1967
29 December 1967
10 January 1968
21 September 1973
28 December 1973
28 December 1973
September 1975
SNETTISHAM PROJECT, ALASKA
FIRST-STAGE DEVELOPMENT
PERTINENT DATA
(Based upon current and prior design memorandums.)
LOCATION:
Near the mouth of Speel River, 28 air miles southeast of Juneau, Alaska.
AUTHORIZED:
PLAN:
Flood Control Act of 1962, providing for design and construction by the
Corps of Engineers and for operation and maintenance by the Alaska Power
Administration, Department of the Interior.
Long Lake
Construct a concrete weir at the outlet of Long Lake to direct the lake
overflow into two natural drainage channels. Drive a power tunnel and
a penstock from Long Lake to an underground powerplant at tidewater.
Install 2 generators in the powerplant. From the switchyard, adjacent
to the powerplant, a transmission line will extend to a substation
near Juneau.
Crater Lake
Drive a power tunnel and penstock from Crater Lake to the underground
powerplant at tidewater. Install one generator in the powerplant.
PROJECT FEATURES:
Reservoir -Long Lake
Elevation of existing lake surface, feet
Elevation of normal full-pool water surface,
Elevation at minimum operating level, feet
Initial active storage capacity, acre-feet
Weir -Long Lake
West elevation -top, feet
-low bay, feet
Length, feet
Height -maximum, feet
-average, feet
feet
Long Lake Crater Lake
815
818
704
138,000
820
818
337
50
5
PERTINENT DATA
Sheet: 1 of 3
Nov. 1973
1,022
1,022
820
84,000
Intake Structure -Long Lake
Type -dry with top deck elevation,
Invert elevation, feet
Base elevation, feet
Slide Gate -size, feet
-maximum oper. head, feet
Bulkhead -size, feet
-maximum head
feet
6.5
7.86
831
684
673.5
wide X 12.5
221
wide X l3.5
221
Gate Structure -Crater Lake
Type -dry chamber in mountain, floor elevation
Invert elevation, feet
Slide gates, No.
-size
-max. operating head, feet
Hydrology
Drainage area, square miles
Annual runoff, average, acre-feet
Annual runoff, maximum, acre-feet
Annual runoff, minimum, acre-feet
Type-modiifed horseshoe
Length, feet
Diameter (lines), feet
Power Tunnel
Long Lake
30.2
324,300
421,000
252,000
Long Lake
8,230
1l.S
684
796+
772+
2
6 X 12
270
Crater Lake
11.4
144,590
155,000
1l3,000
Crater Lake
6,100
9.0
800 Intake invert elevation, feet
Size, feet l3.5 X l3.5 11 X11
Surge Tank
Type-Unlined vertical rock shaft
Diameter, feet
Top elevation, feet
Bottom elevation, feet
Height above tunnel invert, feet
Type-Unlined modified horseshoe
Size, Feet
Length, feet
Invert elevation, feet
Rock Trap
Long Lake
17
960
605
350
Long Lake
18 X 18
205
610
Crater Lake
8
1,150
744
404
Crater Lake
15 X 15
125
746
PERTINENT DATA
Sheet 2 of 3
Nov. 1973
Type -steel lined in rock
Length, feet
Steel penstock diameter, feet
Number units
Installed capacity, kilowatts
Operating head, feet
Penstock
Powerhouse
Annual firm output, kilowatt hours
Switchyard
Capacity, kilovolt-ampere
Transmission Line
Voltage, volts
Conductor, Size MCM, (ACSR)
Lenght of O.H. sections, miles
Conductor, size MCM (copper)
Insulation
Type
Sheath
Armor
Submarine Cable
Cable, length, approximate, feet
Number or cables
Capacity, kilovolt-amperes
Juneau Substation
Capacity, kilovolt-amperes
Long Lake Crater Lake
1,200
8.5
1,590
6
Long Lake
2
46,700
704-820
168,000,000
Crater Lake
1
27,000
820-1020
103,000,000
94,000
138,000
795
40.5
350
Paper
Oil Filled
Lead
Aluminum
16,400
If
124,000
90,000
PERTINENT DATA
Sheet 3 of 3
Nov. 1973
Paragraph
1. 01
1. 02
1. 03
1. 04
1.05
2.01
2.02
2.0/+
2.05
2.06
2.07
2.08
2.09
2.10
2.11
2.12
2.13
2.16
2.17
2.18
3.01
3.02
3.07
3.11
3.12
3.14
3.15
3.20
SNETTISHft~ PROJECT, ALASKA
DESIGN MEMORANDUM NO. 23
CRATER LAKE PLAN OF DEVELOPMENT
Table of Contents
SECTION 1 -GENERAL
Project Authorization
Purpose
Scope
Prior Investigations
Locat.ion
SECTION 2 -RECOMMENDED PROJECT PLAN
General
Stage Development
Reservoir
Consultant's Report
Lake Tap
Power Tunnel
Penstock
Gate Structure
Surge Tank
Access Road
Power Plant
Transmission Facilities
Buildings, Grounds and Utilities
Departures from Project Document Plan
Estimated Costs
SECTION 3 -ALTERNATIVE PLANS
General
Intake Structure Alternative
Power/Access Tunnel Alternative
Penstock Alternative
Diversion Tunnel Alternative
Bulkhead
Gate Structure Alternatives
Tramway
1-1
1-1
1-1
1-·1
1-·2
2--1
2--1
2--1
2--2
2--2
2--2
2--2
2--2
2-2
2--2
2--3
2·-3
2-3
2·-3
2-3
3-1
3-1
3-2
3-3
3-3
3-3
3-3
3-4
Paragraph
4.01
4.02
4.06
4.10
4.16
4.17
4.20
4.21
4.24
4.26
4.27
4.28
4.29
4.37
5.01
5.02
5.03
5.04
5.05
5.06
5.07
5.08
5.10
5.12
.01
6.02
6.03
6.05
6.07
7.01
7.02
7.03
7.04
7.05
7.06
7.07
TABLE OF CONTENTS (Continued)
SECTION 4 -ENVIRONMENTAL CONSIDERATIONS
General
History
Geographical Setting
Climatology
Limnology
Vegetation
Mammals
Birds
Fish
Rare or Endangered Species
Recreation
Wilderness and Scenic Rivers
Environmental Effects -Construction
Environmental Effects -Operation
SECTION 5 -HYDROLOGY
Streamflow Characteristics
Glacial and Permanent Snowfield Effects
Runoff
Streamflow Correlations
Peak Discharges
Spillway Design Flood
Discharge Frequencies
Sedimentation
Ice Studies
Hydrometeorological Data Collection
SECTION 6 -GENERAL GEOLOGY AND SITE INVESTIGATION
Introduction
Project Site Geology
Seismic Considerations
Geologic Explorations
Other Types of Investigations
SECTION 7 -GEOLOGICAL EVALUATION OF WATER WAYS
General Bedrock Character
Power Tunnel Faults
Nature of Fault Zones
Other Remedial Measures
Rock Reinforcement
Concrete Lining
Other f>'plorations
4-1
4-1
4-1
4-2
4-3
4-3
4-4
4-4
4-Lf
4-5
4-5
4-5
4-6
4-7
5-1
5-1
5-1
5-2
5-2
5-2
5-3
5-J
5-4
5-4
6-]
6-1
6--2
6-3
7-1
7-1
7-1
7-1
7-2
7-2
7-2
7.08
7,09
7.10
7" 11
8.01
8.02.
8.03
8.05
8.08
9.01
9.02
lO.O]
10.02
JO.06
10.11
10.12
10.15
11. 01
11.02
11.03
11. 04
12.01
12.02
12.03
12.04
12.06
12.07
TABLE OF CONTENTS (Continued)
SECTION 7 --GEOLOGICAL EVALUATION OF WATER WAYS (Continued)
Penstock and Access Adit
Geology of Other Watenlays Features
Lake Tap Area
Dam Area
General
Energy Losses
SECTION 8 -HYDPAULIC DESIGN
Economic Sizing of Power Tunnel and Penstock
Surge Tank
Fater Hanuner Analysis
SECTION 9 -TURBINE SELECTION
General
Net Turbine Heads
SECTION 10 -POWER CONDUIT
General
Power Tunnel
Penstock
Penstock Trashrack
Intake Trashrack
Rock Trap and Access Adit
SECTION l.1 -GATE STRUCTURE
:}eileral
Recommended Structure
Vep.Lilation
Electrical Power
SECTION 12 -LAKE TAP
Gene"Cal
tZock Trap
Tapping Operation
Tras~rack Installation
Two Step Lake Tap
Div0rsion Tunnel Lake Tap
7-3
7-3
7-3
7-4
8-1
8-1
8-2
8-3
8-3
9-1
9-1
10-1
10-1
10-2
10-3
10-3
10--4
.L-:L
1"-1
_~._-l
11-1
~:Z-l
12-1
l7.-1.
L2--1
12--2
12-2
Paragraph
13.01
13.02
13.03
13.04
13.05
14.01
14.02
14.03
14.04
14.06
14.07
15.01
15.02
15.03
15.04
15.05
16.01
16.02
16.03
16.04
16.05
16.06
16.07
16.08
16.09
16.10
16.11
16.12
16.13
16.14
16.15
16.16
16.17
16.18
16.19
16.21
TABLE OF CONTENTS (Continued)
SECTION 13 -DAM
General
Increased Generating Capabilities
Damsite
Studies
Conclusions and Recommendation
General
Basic Data
Layout and Size
SECTION 14 -POWER PLANT
Turbines, Generators and Electrical Equipment
Tailrace
Construction
SECTION 15 -TRANSMISSION LINE
General
Juneau Substation
Snettisharn Switchyard
Communications
Maintenance
SECTION 16 -ACCESS FACILITIES
General
Recommended Plan
Criteria
Road Type
Lane Width
Shoulders
Guardrail
Turnouts
Grade
Horizontal Curvature
Sight Distance
Vertical Curvature
Cross Slope
Speeds
Clearing
Rock Cut Disposal
Seeding
Slope Dressing
Drainage
Road ~'l,c, ntenance
13-1
13-1
13-1
13-1
13-1
14-1
14-1
14-1
14-2
14-2
14-3
15-1
15-1
15-1
15-1
15-1
16-1
16-1
16-1
l(j-}
16-1
16-1
l6-1
hi-1
16-1
16-2
16-2
16-2
16-2
16-2
16-2
16-2
16-2
16-2
16-2
16-2
Paragraph
17.01
17.02
17.03
17.04
17.05
17.06
17.07
17.08
17.09
17.10
18.01
18.02
18.03
19.01
19.02
19.04
19.05
20.01
20.02
20.03
20.04
20.05
21.01
21.02
22.01
22.03
22 .05
22.06
22.07
TABLE OF CONTENTS (Continued)
SECTION 17 -BUILDINGS, GROUNDS AND UTILITIES
Genel:a1
Donnitory
Transmission Maintenance Building
Tidewater Picnic Shelter
Contractor Facilities
Water
Sewer
Sanitary Landfill
Electrical Power
Other Facilities
General
Tests
Costs
General
SECTION 18 -CONCRETE AGGREGATES
SECTION 19 -PUBLIC USE PLAN
Recreation Opportunities
Recreation Development -Corps of Engineers
Recreation Development
SECTION 20 -DESIGN A~~ CONSTRUCTION SCHEDULE
General
Design Schedule
Construction Contracts
Supply Contracts
Funding Requirements
SECTION 21 -OPERATIONS AND MAINTENANCE
General
Transmission Line
SECTION 22 -COORDINATION WITH OTHER AGENCIES
r;enera1
Forest Service
Fish and Wildlife Interests
Federal Power Commission
Alaska Power Administration
OtlF~r Agencic"s
17-1
17-1
17-1
17-1
17-1
17-1
17-1
17-2
17-2
17-2
18-1
18-1
18-1
19-1
19-1
19-1
19-1
20-1
20-1
20-1
20-1
20-1
21-1
21-1
22-1
22-1
22-1
22-1
22-1
22-2
Paragraph
22.09
22.11
23.01
23.02
24.01
24.02
24.03
24.04
24.06
24.07
24.08
24.09
24.10
24.11
24.12
24.13
24.14
24.15
24.16
25.01
25.03
25.07
l.
2.
3.
4.
5.
TABLE OF CONTENTS (Continued)
SECTION 22 -COORDINATION WITH OTHER AGENCIES (Continued)
Public Coordination
Future Coordination
SECTION 23 -COST COMPARISON
General Design Memo Cost Estimate
Comparison of Current Approved Estimate with
Present Estimate
SECTION 24 -POWER STUDIES, BENEFITS AND ECONOMICS
Introduction
Power Output Computations
Existing Electric Power Resources
Electric Power Requirements
Turbine and Generator Efficiencies
Power Regulation Studies
Normal Full and Minimum Lake Elevations
Normal Full Pool with a Low Head Dam
Installed Capacity
Study Results
Annual Power Benefits
Limiting Alternative Costs
Limited Benefits
Average Annual Value for One Foot of Head
Annual Costs without a Dam
SECTION 25 -CONCLUSIONS AND RECOMMENDATIONS
Discussion
Conclusions
Recommendation
TABLES
Summary Cost Estimate -Recommended Plan
Summary Cost Estimate -Intake Structure Alternative
Summary Cost Estimate -Power/Access Tunnel Alternative
Detailed Cost Estimate -Recommended Plan
Detailed Cost Estimate -Alternatives
22-2
22-2
23-1
23-1
24-1
24-1
24-1
24-2
24-2
24-2
24-2
24-2
24-3
24-3
24-3
24-4
24-5
24-5
24-6
25-1
25-1
25-2
I.
2.
3.
4.
5.
6.
7.
8.
9.
10.
II.
12.
13.
14.
15.
16.
17.
18.
19.
I.
2.
3.
4.
5.
6.
7.
8.
9.
10.
II.
12.
13.
14.
15.
16.
17.
18.
19.
20.
2l.
22.
23.
TABLE OF CONTENTS (Continued)
FIGURES
Climatological Data
Limnological Data
Snow Survey Data
Long River Sedimentation Data
Average Monthly Flows
Mean Discharge Data
Peak Annual Discharge Data
Topographic Features
Crater Creek-Long River Correlation Data
Area Storage -Area Elevation Curves
Tailwater Elevations
Juneau -Douglas Peak Load Growth
Firm Energy Production and Gross Load Requirements
Power Output
Tunnel and Penstock Comparative Costs
Hydraulic Losses
Turbine Output
Power-Storage Tabulation
Design and Construction Schedule
PLATES
Location and Vicinity Map
Project General Plan -Recommended Plan
Geologic Map -Lake Area
Geologic Map -Surge Tank Area
Power Tunnel Geology -Plan and Profile I
Power Tunnel Geology -Plan and Profile II
Penstock Geology
Recommended Power Tunnel -Plan and Profile
Recommended Power Tunnel -Details
Recommended Power Tunnel -Rock Trap and Surge Tank
Reco~nended Penstock
Recommended Power Tunnel -Gate Structure
Recommended Power Tunnel -Alternative Gate Structure Plan
and Profile
Recommended Power Tunnel -Gate Structure Alternative I
Recommended Power Tunnel -Gate Structure Alternative II
Reco~~ended Power Tunnel -Gate Structure Alternative III
Recommended Power Tunnel -One Step Lake Tap
Recommended Power Tunnel -Two Step Lake Tap
Recommended Power Tunnel -Access Road Plan -Schedule I
Recommended Power Tunnel -Access Road Plan -Schedule II
Recommended Power Tunnel -Access Road Details - I
Recommended Power Tunnel -Access Road Details -II
Recommended Power Tunnel -Alternative Gate Structure Access
Road Plan -Schedule I
vii
24.
25.
26.
27.
28.
29.
30.
3l.
32.
33.
34.
35.
36.
37.
38.
39.
40.
4l.
42.
43.
l.
2.
3.
4.
5.
TABLE OF CONTENTS (Continued)
PLATES (Continued)
Recommended Power Tunnel -Alternativp Gate Structure Access
Road Plan -Schedule II
Camp -Plan
Powerhouse and Switchyard -General Plan
Powerhouse Arrangement -Crater Lake Unit: 3
Project General Plan -Intake Structure Alternative
Intake Structure Alternative -Intake
Intake Structure Alternative -Diversion Tunnel
Intake Structure Alternative -Access Road Plan
Project General Plan -Power/Access Tunnel Alternative
Power/Access Tunnel Alternative -Gate Structure
Power/Access Tunnel Alternative -Tunnel and Surge Tank
25 Foot Dam
50 Foot Dam
Tramway
Explorations -Log Records No. 1
Explorations -Log Records No. 2
Borrow Areas -Auger Holes No. 1
Borrow Areas -Auger Holes No. 2
Borrow Areas -Test Pits No. 1
Borrow Areas -Test Pits No. 2
EXHIBITS
Lake Tap Study by Ingeni~r Chr. F. Gr~ner
Report from Anchorage Conference of Feb. 8-9, 1973 by Ingeni~r
Chr. F. Gr¢ner
Preliminary Turbine Selection
Federal Power Commission Letter of 17 December 1971
Alaska Power Administration Letter of 6 July 1973
\'iii
SECTION I -GENERAL
1.01 PROJECT AUTHORIZATION. The Crater-Long Lakes Division l)f the
Snettisham Project was authorized by Section 204(a), Flood Cont~ol Act
1962, Public Law 87-874, in accordance with the plan set forth in House
Document No. 40, 87th Congress, First Session, dated 3 January 1961, as
modified by the Reappraisal Report of Nevember 1961. This act also
authorizes the Secretary of the Army, acting through the Chief of Engineers,
to construct, and the Secretary of the Interior to operate and maintain the
project. The Bureau of Reclamation was the original operating agency by
intent until Department of the Interior Order No. 2900 established the
Alaska Power Administration. The Alaska Power Administration will operate
the project and market the power generated. Subsequent to project author-
ization, the Crater Lake phase was advanced from stage 3 development to
first stage development because of increased power requirements earlier
than originally forecast.
1.02 PURPOSE. Design Memorandum No.3, Selection of Plan of Develop-
ment, reanalyzed the project document plan in light of Corps of Engineers
policies and requirements and made recommendations for both Long and
Crater Lakes to be used in preparation of Design Memorandum No.7, Gen-
eral Design Memorandum. The General Design Memorandum presented the
plan of development for the Long Lake phase, each aspect of which has
been developed in detail in subsequent design memoranda and supplements.
This Design Memorandum presents the plan of development for the Crater
Lake phase, including the pertinent featuresof the waterway, powerhouse,
transmission facilities, and camp renovation.
1.03 SCOPE. This design memorandum outlines the recommended plan of
development for the Crater Lake phase, the considerations which resulted
in the plan, and detailed cost estimates for each portion of the plan.
The alternative plans considered and alternatives to portions of the
recommended plan are also outlined. Significant changes in pmver require-
ments, results of additional investigations, experiences in the develop-
ment of the Long Lake phase, and other factors since thp issuance of
Design Hemoranda 3 and 7, which influenced the recommended plan) are dis-
cussed. The scope has been limited to those studies and investi~ations
necessary, to develop a comprehenGive plan. Detailed studies anu in-
vestigations necessary to the establishment of criteria for and develop-
ment of detailed designs of the various components of the plan will be
presented in feature design memoranda, supplements to this report, and
design analyses, subsequent to approval of this design memorand~m.
1.04 PRIOR INVESTIGATIONS. The (:;ower potentialities 0_ Crater and Long
Lakes were initially investigated by private mining interests in 1913,
with subsequent studies made by private corporations between 1920 and
1928. Although applications were filed with the U.S. Forest Service
and Federal Power Commission, the applicants failed to make beneficial
use of the water and these applications lapsed. Reports by Federal
agencies included the Federal Power Commission, Forest Service, Corps of
Engineers and Geological Survey. The Bureau of Reclamation began more
detailed studies in 1958 and completed a feasibility report in 1959.
That report, entitled "Crater-Long Lakes Division, Snettisham Project,
Alaska", was published in 1961 as House Document No. 40, 87th Congress,
First Session. A reanalysis and reappraisal of the report was completed
by the Bureau of Reclamation in 1961. The initial House Document No.
40, as modified by the reappraisal report, provided the basis for the
project authorization.
1.05 With project authorization, detailed site investigations, mapping,
and data collections were accelerated, primarily concentrated on those
items necessary to the development of the Long Lake phase. Limited in-
vestigations for the Crater Lake phase were also conducted prior to 1972.
Added information has been obtained from the construction of the Long
Lake phase, commencing in 1967. Additional mapping, foundation investi-
gations, and other studiesrequ. ceo {or this design memorandum were
started in 1972.
1.06 LOCATION. The project is located in the Tongass National Forest
near the mouth of Spee1 River and on the Spee1 Arm of Port Snettisham,
a glacial fiord in Southeastern Alaska, (Plate 1). The project is 28
airline miles southeast of Juneau, 45 miles from Juneau by water, and
is located geographically at 58 degrees 08' north latitude and 133 de-
grees 45' west longitude, approximately the same latitude as Stockholm,
Sweden.
1-2
SECTION 2 -RECOMMENDED PROJECT PLAN
2.01 GENERAL. The Project Plan, as presented in U.S. House Document No.
40 and modified by the Reappraisal Report, proposed diversion of water
from Crater and Long Lakes through separate waterways to a common power
plant at tidewater. Each waterway would include a pressure tunnel, surge
tank and underground steel penstock. The location of the project neces-
sitated construction of approximately 40.5 miles of transmission lines
and approximately 2.7 miles of submarine cable crossing of Taku Inlet.
The line terminates in a step-down substation near Juneau.
2.02 STAGE DEVELOPMENT. The Project Plan and Reappraisal Report pro-
posed a three-stage development involving the installation of three
generating units, rated at 20,000 k.w. each, for a total of 60,000 k.w.
Subsequent authorization increased the first two units to 23,350 k.w~
each. The first two units utilize Long Lake water and the third will
be supplied from Crater Lake. The Long Lake phase of first stage develop-
ment (Plate 2) includes construction of: Long Lake watenJays; the power-
house structure, including a skeleton bay for the third unit; the tail-
race facilities; all switchyard and substation structures and improve-
ments; necessary station service equipment to provide for two generating
unit's capacity; the transmission line and all general property; two
turbine generators and appurtenant facilities. The Crater Lake phase
of first stage development will include construction of Crater Lake
waterways and generating facilities and will complete the installation
of all switchyard equipment.
2.03 Crater and Long Lakes serve as storage reservoirs for the project.
A darn at the outlet to Long Lake was authorized for first stage construc-
tion but was subsequently postponed to second stage construction as the
result of re-evaluation of the project. No dam has been proposed at the
Crater Lake outlet. Storage has been obtained at Long Lake and will be
obtained at Crater Lake by tapping the lakes with separate pressure
tunnels at elevations sufficiently below the natural lake levels to
provide adequate storage by drawdown. Both tunnels were originally
planned to be reinforced concrete lined, circular in cross section and
partially supported with structural steel ribs and struts. The Long
Lake tunnel was constructed as an unlined, modified horseshoe, rock tun-
nel partially supported with rock bolts and with short sections of rein-
forced concrete. The Crater Lake tunnel will be similar to the existing
Long Lake tunnel, terminating at a separate surge tank. Welded steel
penstocks will carry the water from each su:::-ge tank to the lmderground
powerhouse.
2.04 RESERVOIR. Preliminary area storage curves for the Crater Lake
Reservoir are shown in Figure 10. After the lake has been initially
drawn down, more accurate surveys will be made and final area storage
curves prepared. Initial storage capacity will be about 121,000 acre
feet with maximum pool elevation 1022 and about 38,000 acre feet of dead
storage at minimum pool elevation 820. Usable storage is, therefore,
about 83,000 acre feet.
2-1
2.05 CONSULTANT'S REPORTS. The Recommended Plan is based on the recom-
mendations of Ingeni~r Chr. F. Gr~ner, Consulting Engineers, of Oslo,
Norway. These recommendations are contained in their reports: "Lake
Tap Study with Recommended Arrangement for Crater Lake", dated January
1973 (Exhibit 1); and "Report from Anchorage Conference of February 8,
9-1973" (Exhibit 2). This firm was also under contract to the Alaska
District during the design and construction stages of the Long Vlke phase.
2.06 LAKE TAP. The lake tap will be made directly into the power tunnel
with the invert at elevation 800, approximately 220 feet below normal
lake level, after the power tunnel is excavated and the operating and
bulkhead gates installed. Both the bulkhead and operating gates will
be closed. A trap will be provided to catch and permanently store the
rock from the final plug. The power tunnel branches off from the side
of the rock trap above the floor level so the rock from the blast will
not be diverted into the power tunnel itself. The lake tap configura-
tion and rock trap are shown on Plate 17.
2.07 POWER TUNNEL. The 11 foot wide by 11 foot high, modified horseshoe,
unlined power tunnel will extend approximately 5,930 feet from the lake
to the upper end of the steel lined penstock, Plates 8 and 9. The down-
stream end of the power tunnel will also be a trap to collect any loose
rock moving down the tunne 1. A half trashrack will be situated at the
lower end of the rock trap, the upper end of the penstock, Plate 10.
2.08 PENSTOCK. A steel lined six foot diameter penstock will extend
horizontally, approximately 500 feet, from the power tunnel rock trap,
then plunge downward at a 45 degree angle, leveling off immediately up-
stream of the existing underground powerhouse valve chamber at elevation
7.5, Plate 11. The penstock will connect with a spherical valve in the
valve chamber. Downstream of the valve, a penstock extension will con-
nect to the unit 3 turbine.
2.09 GATE STRUCTURE. The gate structure, housing two hydraulically
operated slide gates, the upsteam one serving as a bulkhead and the down-
stream one as an emergency gate, will be located in a chamber in the
mountain approximately 800 feet downstream of the power tunnel entrance,
Plate 12. The gate structure chamber will be dry, housing the electrical
equipment, a hoist capable of servicing the slide gates, and the hydrau-
lic equipment. Access to the gate chamber will be by tunnel from the
upper access road. The power tunnel air shaft will be in the access
tunnel for part of its length, rising vertically through the mountain
above the tunnel to vent.
2.10 SURGE TANK. An eight foot diameter unlined rock surge tank will
rise approximately 340 feet above the power tunnel, connected to the
power tunnel rock trap by a horizontal tunnel or drift, Plate 10. The
surge tank will open vertically to the ground surface.
2.11 ACCESS ROAD. The access adits to the power tunnel rock trap and
to the gate structure will be reached by extending the existing Long Lake
'j
access adit road around the mountain, climbing at a maximum grade of 10
percent, Plates 19 through 22. The road extension will be approximately
5,600 feet long, surfacing will be compacted gravel fill, and the width
will be 12 feet.
2.12 POWERPLANT. A 27,000 k.w. generator, turbine, spherical valve, and
appurtenances will be installed in the skeleton third unit bay of the
existing underground powerhouse to be driven by the ,Yo.ter from Crater
Lake only, Plates 26 and 27. No changes in existing m~n~mum anQ maximum
tailwater levels or in the existing tailrace channel are proposed.
2.13 TRANSMISSION FACILITIES. The 3-phase transmission line has 40.5
miles per phase of 795 MCM ACSR overhead conductor supported on a combi-
nation of guyed delta and single pole and self-supporting green anodized
aluminum towers. The submarine cable portion of the transmission faci-
lity consists of 16,000 feet per phase of aluminum armored, lead sheathed,
oil filled, paper insulated, 350 MCM copper conductoGone cable per phase
with a spare cable (Plate 1).
2.14 The overhead line has a manufacturer listed continuous rating of
215 Mva (900 amperes). This size wire was chosen of larger rating to
compensate for voltage regulation. The submarine cable limits the trans-
mission facility ampacity with a continuous rating of 383 amperes per
cable (91.5 Mva, 3-phase) and with a one hour overload capability, after
maximum load, of 437 amperes (104,5 Mva). The Juneau Substation trans-
former capacity is 106 Mva OA/FA at 55 degrees C. rise.
2.15 The Juneau Substation status switchboard will include unit 3 status
and alarm features, and MW recorder.
2.16 BUILDINGS, GROUND AND UTILI~~IES. The existing camp facilities will
be converted to maintenance, operating, and visitors' facilities on com-
pletion of the Crater Lake development, Plate 25. A new aerated sewage
lagoon will be constructed to replace the existing septic tank.
2.17 DEPARTURES FRON PROJECT DOCUMENT PLAN. The Project Document Plan
for the Crater Lake phase proposed a separate diversion tunnel to tap
the lake, drawing it down for construction of the power tunnel. The
recommended plan to tap directly into the power tunnel eliminates the
separate diversion tunnel and its related gate structure. The Project
Document Plan also proposed a rei~forced concrete lined power tunnel
and concrete lined surge tank witi a wheeled gate in an intake structure
at the lake end of the power tunn.2l. The recollunended plan proposes an
unlined rock tunnel and surge tan:C within the mountain, and a chamber in
the mountain housing two hydraulically operated slide gates. Instead of
a trashrack at the face of the intake structure, the proposed plan in-
cludes a trashrack over the entra~ce to the unlined power tunnel. Other
changes from the Project Document Plan include reducing the penstock
diameter from seven feet to six f2et.
2.18 EST1.>11\TED COSTS. The estimated construction cost for the recom-
.... --.,,~,~~ ',~ > •• -.~~,.-.. "'.-~--
mcuc1ed r)"'Cr :~ 1,.'1n fcy:" j~~vekpment cf Crater Lake, based on 1973 price
levels, is $21,661,000 excluding interest during construction. These
estimated costs are summarized in Table 1 and detailed in Table 4.
~ , L-,"
SECTION 3 -ALTERNATIVE PLANS
3.01 GENERAL. Two basic alternative plans for development of Crater
Lake have been ~tlldied in some depth, the Intake Structure Alternative
with a diversion tunnel and the PowerjAccess Tunnel Alternative. In
addition, a1ternati',rps are r-re~ented for the recOll1mended plan gate struc-
ture, lake tap, and aCCE:,:::: roads.
3.02 INTAKE STRUCTURE ALTERNATIVE. plates 28 through 31 present an
alternative scbeme to the recommer~ded plan , .. herein the lake is drawn
down through a lake tap and a separate diversion tunnel on the bouth
side of Crater Creek, the power tunnel is "holed through" without a lake
tap, and the gate structure is replaced by an intake structure at the
lake end of the powel." tunnel. This scheme is similar to the plan used
in the development of the Long Lake phase of the project.
3.03 The diversion tunnel, Plate 30, wuu1d be constructed by excavation
from the downstrc3;il end to the rock t.rap. The gate structut"e, housing
one slide gate, ',lOU 1,1 1,," constructed 3t the dmvtlstn>dm end of the diver-
sion tunnel. A small lnlp Vlou1d be provided at tlte tunnel invert immedi-
ately downstream o[ the tap area to catch and hold the rock [rom the tap-
ping operation temporarily, permitting the rock La escdpe downstream
gradually so that J large mass of ruck will not plug tIle gate structure
or tunnel. The diversion tunnel gate structure would be provided with
a pennanently embedded gatr, frame and the operating slide gate would be
used temporarily at this locat ion and (:hen moved to its pennanent loca-
tion in the power tunnel gate slructure after a permanent plug is placed
in the diversion tunnel. Fragments of rock aud water from the capping
operation would be discharged int0 Crater Creek dnd eventucillj transported
to Crater Cove.
3.04 The intake structure 'voult! LaUbe a single slide gdte in a dry well
and a steel bulkhead in a Het '''eL~> (Pldte ',ct.). The intake structure
would be cons trueted in the dry' aiter the 1ab,;s drawn dOW,l, plSS ing
the water through the diversion tlili1l2:. DONlls,reci,n of C'll' ~iltCi(e struc-
ture, the unlined power tWHlel, :3urg(' t"lk, and p,~asl:ock \·,iOu1d be iden-
tical to those prop()3cd in the l:ecOllllnC'idect pi_an.
3.05 Access to the intake structu:ce would be hy bridge a,1'.1 9275 feet of
main access road from the existin~ Lung Lak~ adit to Crater Lake (Plate
31). This is 3675 leet :nore oi: m".in access road than is re'..juired for
the proposed plan. Ac>::E.~SS must also be provided to the diversion tunnel
outlet; a 12-foot wiele (siegle lane) 3,OOO-foot long a.:: .. ess road was en-
visioned with d temporary bridge DV2r Crater Creek. The diversion road
would have been landscaped and ab~ndoned after construction.
3.06 This alternative requires a separate diversion tunnel with gate
structure and more roads. It would result in discharging rock into
Crater Creek during the lake tapping process. The esti.mated construc-
tion cost is $1,4S9,:;i)U ;Clore than the recomr.ended plan, It would pro-
vid<~ a rr;e8.n,c,· (.: '_lmn:.-eri '-i' tIle entire po\Ver tH!mel, a methud for
dr:t, i.l1£': "~,.';.,ergt;nc and:3 i"e; srll:':lck ell
the upper end of the power tunnel at the time of intial filling. The
water in the lake would be wasted in the intial drawdown and construc-
tion would take longer, delaying power on the line. Rock excavation
volume and disposal site areas would have heen comparahle to the pro-
posed plan. This alternative was not selected because of comparably
higher environmental and economic costs.
3.07 POWER/ACCESS TUNNEL ALTERNATIVE. The power/access tunnel alterna-
tive scheme (Plates 32, 33 and 34) differs from the recon~ended plan
only in that portion of the power tunnel from the gate structure to the
upper end of the recommended penstock. The essential difference is
that the water conduit would be an 8 foot diameter steel penstock em-
bedded in concrete in a trench in the bottom of the unlined tunnel from
the gate structure to the upper end of the penstock. The tunnel would
serve as the means of access to the gate structure, eliminating that
portion (about 4150 feet) of the access road up the mountain from the
surge tank access adit (Plate 20). About 1,450 feet of road would still
have had to have been constructed from the Long Lake access adit road to
the upper access adit.
3.08 The gate structure is very similar to the recommended gate struc-
ture, housing 2 slide gates in a dry chamber, (Plate 33). A trashrack
would be installed immediately upstream of the gate structure at the
downstrean end of the unlined power tunnel instead of at the upper end of
the penstock at Sta. 65+40 as in the Recommended Plan. This rack would
be inaccessible for cleaning. The access adit from the top of the gate
structure to the upper access road and associated disposal area would
be eliminated.
3.09 An eight foot diameter steel penstock, encased in concrete, would
be buried in a trench in the bottem of the tunnel, (Plate 34). The pen-
stock would be designed to withstand full internal pressure with steel
stresses limited to 25 percent of minimum tensile strength with no con-
sideration of rock restraint because of the tunnel immediately over the
penstock. From Sta. 65+65 downstream, the penstock would be 6 feet in
diameter and designed to the same criteria as in the recom.'11ended plan.
3.10 This alternative has less impact on the existing environment than
the recommended plan because a large portion of the access road, one
access tunnel and a disposal area would be eliminated. The related dis-
posal volume to be placed in the reLlaining disposal area would be
greater (an additional 10,000 cubic yards) because of the increased
power tunnel excavation but would not have necessitated enlarging the
disposal area. There would have also been enough area for an adequate
buffer zone around the disposal area. The length of unlined power pres-
sure tunnel would be reduced considerably and the requirements for treat-
ment of faults and other undesirable rock conditions in the power tunnel
would be reduced. This alternate is estimated to cost $7,554,000 more
than the recommended plan.
3.11 PENSTOCK ALTERNATIVE. A study was made of an 8 foot diameter
steel lined penstock extending horizontally upstream from the power-
house to where the required minimum rock cover was achieved for an
unlined power tunnel. This penstock was 1,824 feet long. A full tr:lsh-
rack and a rock trap would be required at the upstream end of the steel
penstock. Immediately upstream of the rock trap, the unlined power
tunnel rose at a 45 degree angle to interce?t the flatter portion of the
recommended power tunnel. At the upper end of the inclined portion of
the tunnel, a rock trap and surge tank would be located; This penstock
scheme is more expensive than the recommended plan because of the in-
creased length and thickness of steel required and has no advantage
over the recommended plan. Maintenance is also more expensive because
of the need for an additional rock trap near sea level with required
access to it.
3.12 DIVERSION TUNNEL ALTERNATIVE. The diversion tunnel, shown on Plate
30 as part of the Intake Structure Alternate, is also an alternative by
itself to the recommended plan. In this concept, the diversion tunnel
would be constructed to draw the lake down and the recommended power
tunnel would be holed through without a lake tap into the power tunnel.
This scheme would provide a permanent tunnel for emergency drawdown of
the lake if it became necessary to gain access to that portion of the
power tunnel upstream of the gate structure.
3.13 The additional diversion tunnel, diversion gate structure and ac-
cess road make this alternative cost $2,494,000 more than the recommended
plan.
3.14 BULKHEAD. A bulkhead at the lake end of the tunnel was considered.
The detailed rock surface conditions and configuration above the tunnel
are unknown at present and cannot be known with certainty until the ini-
tial lake drawdown. Detailed rock su~face information is required to
design the track for an operating bulkhead because the guides must be
mounted on the rock surface. Ice conditions in the lake for much of the
year make maintenance and operation of the bulkhead extremely difficult.
A means of access for operating and maintaining the bJlkhead would be
required. No detailed study was nade.
3.15 GATE STRUCTURE ALTERNATIVES. The recorrunendeu gate structure is of
the dry well concept, housing two hydraulically operated slide gates in
series, in a small chamber in the rock inrrnediately above the power tunnel
(Plate 8). Two alternative gate systems in dry wells and 3 alternative
gate systems in wet wells were considered.
3.16 One alternative gate system in a dry well that was considered was
essentially identical to the recommended gate structure except that the
access adit to the chamber was above ::11e maximum pool level wit~ an
additional access adit to the lake wall above the tunnel entrance (Plates
13 and 14). This system would provide a means of access to the lake,
reduce the length of adit required from the upper access road, and re-
duced the length of air vent. It would require a vertical shaft about
280 feet high with an elevator, and increase the length of upper access
road. This concert is $1,182,000 more expensive than the recommended
structure.
3.17 The other alternative gate system in a dry well is one in which
the upstream slide gate would be replaced by a bulkhead in a wet well
with the same vertical shaft and access adits discussed in paragraph
3.16 above (Plate 15). This would require a concrete wall extending
the entire height of the gate shaft to separate the bulkhead from the
dry well. Seismic activity could rupture the wall between the bulkhead
slot and dry well flooding the dry well. This alternative would not
permit the Geletion of the concrete lining of the dry well as is pos-
sible for the other gate structure alternative above.
3.18 The 4 alternative gate systems in wet wells (Plates 14, 15 and 16)
require a bulkhead at the lake end of the tunnel, discussed in paragraph
3.14, or a separate wet well bulkhead, discussed in paragraph 3.17. All
4 alternatives require gate operation from the top of the shaft, 280
feet above. Installing and maintaining a slide gate stem that long
(Plate 15) in alignment is difficult.
3.19 A dry well with easy access to the operating gate is more desirable.
Placing the gate operating machinery adjacent to the gate with only a
flexible electrical connection for operational control from a remote lo-
cation is less vulnerable to interruption due to seismic disturbances.
3.20 TRA}~AYo A tramway, (Plate 37), was studied as an alternative
means of access to the edit to the gate structure in the recommended
plan, eliminating the access road beyond the surge tank access adit.
The tramway was not considered for the IntaKe Structure Alternate because
it would not provide access to the diversion tunnel. It was not required
for the Power/Access Tunnel AlterLate.
3.21 The tramway would have consisted of 15 towers; each tower site
would have required vegetation clEaring. It would have extended from
the existing Crater Cove haul roae to the portal of the upper access
adit, and would have. eliminated the necessity for an access road beyond
the lower access adit; the 1,450 feet of road from the existing Long
Lake road to the lower access adit would still have been required. The
tramway alternative was not select.ed because it would have limited flex-
ibility in the type and size of construction and maintenance equipment
that could have been transported to the upper access adit. It is esti-
mated to cost $500,000, slightly in excess of the cost of the upper
access road.
SECTION 4 -ENVIRONMENTAL CONSIDERATIONS
4.01 GENERAL. This section provides an accounting of existing environ-
mental conditions and evaluates the environmental effects which would
result from construction and operation of the proposed Crater Lake de-
velopment. A complete Environmental Impact Statement entitled "Snetti-
sham Project -Crater Lake Development and Operation & Maintenance of
the Snettisham Project" is being prepared and will be submitted to
all interested Federal, State, and local agencies and organized citizen
groups for review.
4.02 HISTORY. The Port Snettisham and Speel Arm areas were discovered
by Lieutenant Joseph Whidby in 1794 while on an expedition led by the
English navigator, Captain George Vancouver. Captain Vancouver named
the fiord "Snettisham." At the time, Vancouver was looking for a
northwest passage through the American continent.
4.03 Prior to the nineteenth century, the Snettisham region was affected
to only a minor degree by man or :nan-made developments. At one time
the area was used by fur trappers. The old village site of Snettisham,
located near the mouth of the Speel River, was a way-post for travelers
passing to and from the Canadian Interior. The village was active from
1900 to 1926 and is still in evidence today. There is a small abandoned
pulpmill which sets on the east side of Speel Arm about three miles
south of the Snettisham Project area. The pulp mill was the first of
its kind in Alaska and was constructed in 1921; it was active until
about 1925 when the venture proved unprofitable. Other historical
human activities in the Port Snettisham fiord include commercial
fishing and mining.
4.04 Intensive development of the Snettisham area was initiated by the
Federal Government in June 1967 when the Corps of Engineers began work
on the Snettisham project to provide electrical energy for the communities
of Juneau and Douglas, Alaska.
4.05 Examination of the "National Register of Historic Places," as
required by the National Historic Preservation Act of 1966, indicates
there are no officially designated archeological or historic sites in
the Snettisham area. Contact witi the State Division of Parks Histor-
ical office revealed that the State's inventory had no archeological
or historical sites recorded for the Snettisham area.
4.06 GEOGRAPHICAL SETTING. Crat~r Lake lies in the Tongass National
Forest on the Southeast Alaska mainland. It is perched above and about
3/4 mile from an embayment of Speel Arm, a narrow estuary at the terminus
of Port Snettisham. Port Snettisham, a 10 mile long fiord, extends
northeastward from Stephens Passage about 15 miles southeast of where
Stephens Passage, Taku Inlet and Gastineau Channel join.
4.07 Crater Lake is at an elevation of 1,022 feet above mean sea level,
occupying 2. narrow trough about 1/2 mi le wide with precipitous sides
tha~ rise tc slevarions between 4,000 and 5,000 feet. The head of the
Crater Lake basin has the appearance of a glaciated valley and slopes
gently back to more precipitous terrain.
4.08 The drainage basin is about 11,4 square mUes in area above the
outlet. Of this, 3 to 4 square Diles or aboul 30 percent of the total
drainage basin is covered by perr.1anent snow ~md ice fields and glaciers.
The average annual runoff in the basinls watershed is about 150,000
acre-feet of water.
4.09 Crater Lake is about two miles long, about 0.4-miles wide and
consists of about 503 surface areas at elevation 1022. The maximum
depth that has been measured in the lake is 414 feet and is about 1/2
mile from the outlet.
4.10 Crater Lake is principally fed by Crater Creek, a braided glacially
turbid stream which threads its way between gravel and boulders until
it empties into the head of the lake. The lake is drained by Crater
Creek which descends about: 1.4 miles to an embayment of the Speel Arm
estuary.
4.11 CLIMATOLOGY. The Port Snettisham region lies within the mari-
time climatic zone of Alaska and is in the path of most cyclonic storms
that cross the Gulf of Alaska. The region is generally characterized
by moderate temperatures at sea level, high precipitation and snow-
fall, high humidity, and little sunshine. The effects of orographic
lifting of moist maritime air exert a fundamental influence upon local
temperatures and the distribution of precipitation, creating con-
siderable variations in both weather elements within relatively short
distances.
4.12 Detailed climatological data are not available for the area
tributary to Crater Lake; however, short records of precipitation and
temperature are available for a station at the mouth of Speel River.
This climatological station has a thermograph and precipitation gauge
and has been operated intermittently since August 1970. The data
collected are surmnar i7ed in Figure 1.
4.13 According to precipitation data recorded at the Speel River
Station, the average annual precipitation at sea level is about 141
inches. Because precipitation varies considerably with elevation, the
station was not considered repres~nLative of the Crater Lake area.
Annual precipitation of the Crater Lake area was c~lculated by the
Corps of Engineers using the size of the drainage basin and the average
annual flow of Crater Creek. Estimated precipitation of Crater
Lake is about 230 inches annually. Generally, the months of April
through July mark the period of lightest precipitation, with monthly
averages at Speel River ranging from about 4 to 8 inches. After July
monthly precipitation increases until the peak month of October with
an average of about 20 inches. Tnen monthly averages decline from
November to April.
4.14 Some temperature records have been maintained in the vicinity
of the mouth of Speel River since August 1970 but temperature data
are not available for the Crater Lake Area. Temperature variations,
both seasonal and daily, are usually confined to relatively narrow
limits by the characteristic maritime influences. Differences between
average daily maximum and minimum temperatures range from 9 0 F. in
December to about 23° F. in June, Seasonal variations range from
an average iilonthlytemperature of about 25 0 F. in January to about
55° F. in July. The mean annual temperature at sea level is about 40 0 F.
4.15 Snowfall records are available for the immediate vicinity of the
project frO[11 October 1970 to date. Snow depth data (Figure 3) have
been recorded since the winter of 1964 -1965 at four stations in the
Snettisham area (see Figure 8 for location). While the first snow
usually falls in the latter part of October, generally, there is very
little accumulation on the ground at low elevations until late
November. At higher elevations, snow cover is established in early
October. Snow depths generally average over 100 inches during winter
months; however, at the higher elevations in the Crater Lake basin
snow depths exceed 20 feet. Maximum snow depths usually occur in the
month of Narch with heaviest snowfalls from December through April.
Snow cover usually disappears by mid-May, except at higher elevations
where permanent snowfields persist year-round.
4.16 LIMNOLOGY. Basic information of the chemical, physical, and
biological conditions of Crater Lake were collected by the Bureau of
Sport Fisheries and Wildlife in 1958 and 1959. Physical and chemical
limnological observations generally included: color, secchi trans-
parency; water temperatures, dissolved oxygen and carbor dioxide;
and bathymetrLc data. Biology limnological observations consisted
of aquatic vegetation and fishery resources. Limnological data is
summarized in Figure 2.
4.17 VEGETATION. The Snettisham region lies within the northern
coniferous coastal forest biome ~yhere the principal tree spec.Les are
Sitka spruce and western hemlock with lesser amounts of w(:stern red
cedar and Alaska yellow cedar. ~Che forest cover extends from tide-
water to about the 4,000-foot level or to the ice cap. Normally,
timber of cormnercial quality does not extend above the 1,000-foot
elevation level.
4.18 Although forest cover is s?arse in the Crater Lake basin, the
mountain sides are timbered where rockslides and snow avalanches are
not common occurrences, The fon}st cover is interrupted in many
places by the exposure of bare rock and talus slopes or by the pre-
sence of muskeg on poorly drained sites. Alders and willows grow to
a height of about 10 feet and doninate the landscape in the upper,
gently sloping, Crater Lake valley and on some talus slopes. Other
shrub species present are huckleberry, blueberry and devils club.
4.19 N,) c}(iuatic (em€:1"gcnt or submergent) vegetation has been observed
\ C1' ;~~,~ ,'(,:,
4.20 MAMMALS. Wildlife species resident in the vicinity of Crater
Lake include brown and black bears and Sitka black-tailed deer.
Mountain goats are occasionally observed on the higher slopes of the
drainage basin. Other manunals inhabiting the area are hoary marmots,
beaver, mink, marten, otter, wolverine, wolf, and weasel. In addition,
the Speel Arm/Port Snettisham area supports larger numbers of harbor
seals.
4.21 BIRDS. There are over 200 species of birds inhabiting south-
east Alaska, but an accurate checklist of birds for the Snettisham
area has never been assembled. According to the Bureau of Sport
Fisheries and Wildlife, upland game birds present in the Snettisham
region include willow ptarmigan, blue grouse, and Franklin's grouse.
The Northern bald eagle is quite common in the Snettisham area.
4.22 The Bureau of Sport Fisheries and Wildlife has reported that
the sedge flats or wetlands (primarily Gilbert Bay and Crater Cove)
within Port Snettisham receive heavy use by waterfowl. In 1959, the
Bureau of Sport Fisheries and Wildlife reported that waterfowl have
been observed to heavily utilize (primarily for feeding) the exten-
sive wetlands near the mouth of Speel River and Crater Cove. In
September 1963 about 500 waterfowl were observed about 10 miles south
of Crater Cove, i.e., in the Gilbert Flats area. In the spring of
1973, the Bureau of Sport Fisheries and Wildlife and Alaska Fish and
Game implemented an aerial waterfowl survey of, in part, the Port
Snettisham area. On 11 April 1973, 283 waterfowl were observed in the
vicinity of Crater Cove (Watson 1973). The mallard and buffelhead
counts represented 42 and 49 percent, respectively, of all mallards
and buffleheads fed in the entire Port Snettisham area. On 18 April
1973, 110 ducks were sighted in Crater Cove. On 24 March 1973 about
150 waterfowl were sited in the cove. Approximately 100 mallards
were observed in Crater Cove on 3 May 1973 and on 10 May, an estimated
200-300 waterfowl were sited in the cove. It appears that Crater
Cove is one of three important waterfowl habitat areas in Port Snet-
tisham.
4.23 Generally waterfowl use of the Crater Cove area consists of
feeding and resting activity during the spring and fall migratory
periods. Since Crater Lake is frozen over from November to July,
waterfowl utilize Crater Lake only during the fall and, then, only
for resting.
4.24 FISH. According to the Bureau of Sport Fisheries and Wildlife
no fish inhabit Crater Lake. Introduction of fish by natural means
has been prevented by the presence of impassable cascades in the out-
let stream--Crater Creek. Features that have limited the value of
Crater Lake as fish habitat are: the lake is turbid from being fed
by glacial melt waters; runoff waters contain few nutrients due to a
lack of soil. development in the basin; few bottom d\velling organisms;
lack of aquatic vegetation; and the lack of or the poor quality of
potential soawn:Lng habitat due to glacial silt and the steep gradient
of the shoreline. Except for the delta area surrounding the upper
end of the lake, the shoreline is steep and rocklined and does not
offer habitat that is particularly attractive to any wildlife species.
The deltic area at the head of the lake is composed of glacial gravels
and boulders and could be invaded by aquatic plant species as the water
level is gradually lowered. Although not particularly significant,
the emergent vegetation coald provide a small amount of feeding
habitat for waterfowl.
4.25 Dolly Varden trout, and pink and chum salmon have been reported
to utilize the intertidal channels in Crater Cove; however, there are
no accurate or documented reports of the number of salmon that have
spawned in the past in the cove's intertidal channels. In May 1973
the National Marine Fisheries Service conducted a survey of the spawn-
ing habitat in Crater Cove. The National Marine Fisheries Service
indicated they could find no evidence of past spawning activity; how-
ever, they did find that the upper intertidal channels near the mouth
of Crater Creek contained about 100 square meters of potential spawn-
ing habitat. This habitat could accommodate about 100 pairs of
spawning salmon. Assuming conditions and fish stocks similar to
those in other southeast Alaska pink and chum salmon streams, the
National Marine Fisheries Service estimated the potential contribution
to the salmon fishery from Crater Creek to be about 500 salmon. A
catch of 500 pink salmon would represent about $360 to the fishermen
and the same number of ehum at $1,220 at 1972 prices. At Seattle
broker prices (June 1973) the w~olesale value of 500 pink salmon in
the can would be about $1,030 and $2,460 for chum salmon.
4.26 RARE OR ENDANGERED SPECIES. There are no known rare or endangered
wildlife species from the published list '~are and Endangered Fish
and Wildlife of the United States~ issued by the Fish and Wildlife
Service, inhabiting the Snettisham region. However, the Northern bald
eagle, a subspecies of the endangered Southern bald eagle, is quite
numerous in the area.
4.27 RECREATION. In the past there was little recreation use made of
Crater Lake or of the Snettisham area in general due to the remoteness
of the region. There has been some sport salmon fishing activity in
the Speel River and some goat hunting in the higher elevations of the
region. Since the Corps of Engineers began construction of the Long
Lake phase in 1965 and built the airstrip and boat basin, there has
been an estimated 250 persons per year visiting the Speel Arm area in
pleasure watercraft or aircraft. On some weekends during the SUlmner
of 1972, there were seven to nine pleasure boats moored in the Snet-
tisham small boat harbor. In 1972 about a dozen organizations visited
the Snettisham project. Section 19, Public Use Plan, discusses recrea-
tional opportunities at Snettisham.
4.28 WILDERNESS AND SCENIC RIVERS. The proposed development is
neither within a designated or proposed wilderness area nor has Crater
Creek been proposed for inclusion in the system of wild and scenic
rivers. In 1960, the Tracy Arm-lord's Terror Wilderness Study Area
was created by the Forest Service. This area is located on the east
side of Port Snettisham and extends around the northern side of the
project area. Today, the area is being studied for possible inclusion
in the wilderness study area syscem.
4.29 ENVIRONMENTAL EFFECTS -CONSTRUCTION. Presently identifiable
impacts that will occur with the construction of the Crater Lake pro-
ject are: the removal of vegetation for construction of the access
road and for disposal of rock excavation from the power eondui t, and
rock blasting, excavation, and disposal from construction of the power
conduit, access adits and access road.
4.30 There will be about 30,000 cubic yards of rock blasted and re-
moved from the power conduit and two access adits. Rock material
excavated from the upper access adit will be wasted down the slope
near the mouth of the adit and allowed to seek its own path down the
steep hill to create the appearance of a natural rockslide. Disposal
in this manner will necessitate committing about four acres to a
disposal area. There are several natural rockslides in the vicinity
of Crater Lake with a large amount of exposed rock, and the hillside
is not heavily vegetated; therefore, little change in the natural
character of the landscape is anticipated. The hillside is neither
critical wildlife habitat nor is the area vital to the maintenance of
the surrounding habitat or ecosystem.
4.31 Rock removed from the power tunnel via the lower access adit
will be disposed of in about a 4-acre area near the mouth of the adit.
This heavily timbered area will be cleared of vegetation prior to
stockpiling the rock. The timber will be used to construct a log
barrier on the downhill side of the disposal area to help contain the
rock. Excess timber will be burned in compliance with Forest Service
stipulations. A timbered buffer zone about 200 feet wide around
most of the disposal area should adequately shield the disposal area
from view from the construction camp/recreation area at sea level and
from other sea level areas in Speel Arm. There will be a loss of
about four acres of forest habitat and concommitantly the small marrnnal
population inhabiting the area. The disposed rock will create new
habitat for small mammals, but not necessarily the same types oC marrnnals
thatpreferred the forest habitat. The 4-acre area is not considered
to be critical wildlife habitat Ci:" Jital to the maintenance of the
animal populations in the vicinity.
4.32 Rock excavated from the pe~stock tunnel will be taken out of
the powerhouse entrance and used in upgrading the road adjacent to
the powerhouse. Disposal in this manner is not expected to have any
significant biological or aesthetic impacts as the area has already
been disturbed by powerhouse construction activities.
4.33 The major environmental impact of the Crater Lake Project will
be the construction of the access road. The road will be about 5,600
feet long, 12 feet wide, extending from t[-,e existing Long Lake adit
road to the upper Cracer Lake access adit. To prevent erosion, con-
struction will incorporate side drainage ~itches, culverts for cross
drainage, and culverts at stream crossings. The existing landscape
affected by road construction is very steep terrain which is thinly
vegetated with conifers, alders, and willows of varying size.
4.34 Timber and slash cleaned from the road right of way Hill be
disposed of according to Forest Service stipulations.
4.35 Rock excavated from the road cut wi 11 be used for fi 11 material
in the fill sections of the road and turnouts. Rock that cannot be
used for fill will be disposed of in the designated rock disposal
sites.
4.36 The Crater Lake phase of construction will require about 17,000
cubic yards of processed sand and gravel. There are two borrow sources,
both are eXlsting or developed borrow pits. No new borrow pits will
be opened. Both borrow pits wi.ll be landscaped upon completion of
the project. Landscaping features will include grading and smoothing
the borrow pits to conform to the natural topography of the adjacent
area and top soil will be replaced and climate adapted vegetation
planted and fertilized to prevent erosion. All solid waste and
other refuse will be disposed of in the existing sanitary fill. On
all rock faces, loose or potentially dangerous rock will be dislodged.
4.37 EtNJROmlENTAL EFFECTS -OPERATION. Presently identifiable im-
pacts associated with the operation of the Crater Lake phase of the
Snettisham Project are: seasonal fluctuations in the water levels
of Crater Lake; dewatering of Crater Creek below the lake outlet;
redistribution of freshwater flmv in the intertidal channAls of Crater
Cove; loss of intertidal channel salmon spm·ming in Crater Cove; and
economic and social changes associated with a dependabL~ power supply
in the Juneau power market areas.
4.38 A change in the hydrologic system will result from the con-
struction and operation of the Crater Lake development. The anticipated
seasonal fluctuations in the water level of Crater Lake is 202 feet.
The water level of Crater Lake will be lowered, due to the use of
water for power generation with almost no inflO\" from November through
May, with t.he minimum pool level occurring in May. The seasonal
water fluct1lation will not have 8n adverse effect on m1y wildlife
species.
4.39 The primary hydrologic impact will be the perodic dewatering
of Crater Creek, i.e., as the water level of Crater Lake is lowered
flows from the J_ake into Crater Creek ,viLl be eliminated. The creek,
however, will continue to receive some side flow (less that 50 CFS)
from the se\!cral small streams enterin,:; Crater Creek below the outlet
of Crater Lake. Durin3 years that have above average runoff from the
winter ;::W".·) ,:.£!(:/o!.' Sd!ml1er pr<2cipiLltion, Crater J~3ke \Vil1 refill
during the surrnner months to the point that water will be spilled
through the outlet into Crater Creek. This spillage is not expected
to occur often, so, for all practical purposes, the creek can be
considered to be dewatered after the initial operation of the third
turbine. The decrease of flows in Crater Creek will significantly
affect the aquatic ecosystem of the creek, however the creek has
little value as fish habitat.
4.40 The decrease in flow coming from the mouth of Crater Creek would
serve to change the salinity of the upper Crater Cove area. The
average annual flow of Crater Creek is about 200 cubic feet per second.
With the elimination of flow from the lake outlet, the average annual
flow in Crater Creek is estimated to be less than 50 cubic feet per
second. This should have an effect on the established intertidal
biota in the upper cove. There will be freshwater input to the cove
from the power plant operation. This freshwater will include the
entire diverted flow from Crater Lake plus the flow diverted from
Long Lake, increasing the total volume of freshwater in Crater Cove.
The National Marine Fisheries Service has stated that general con-
figuration of the bottom composition of the substrate, the high
probability of low flows and freezing conditions during winter months,
leads them to believe that Crater Cove's intertidal area is a marginal
salmon producer at best and that any loss will not have a significant
impact on the commercial fishery.
4.41 Secondary impacts associated with the project could involve
social, cultural, economic, and land use impacts. Operation of the
entire project in 1977 will provide the Juneau power market area with
73,700 kilowatts (274 million kilowatt hours annually) of hydro-
electric generating capacity. This power supply will provide for a
dependable source of electrical energy for residential, commercial,
and possibly industrial power uses. The Snectisham power supply is
taking the place of the present diesel generated power supply. The
replacement of the present diesel generated system with a hydro-
electric power system should improve the air quality in the Juneau-
Douglas area. The provision of hydroelectric power will serve to
decrease the consumption of petroleum based fuels which are presentl y
in short supply. In addition, the new power supply is expected to be
more reliable than the present diesel generated system and replacement
will be at a slightly lower cost than the present system. A more
reliable source of power may enco-....:~ge residential, cormnercial,
industrial, and recreational growth which in turn may lead to changes
in land uses and established social patterns. Problems associated
with providing additional domestic water supplies and waste treat-
ment and school facilities may arise.
SECTION 5 -HYDROLOGY
5.01 STREAMFLOW CHARACTERISTICS. Runoff characteristics of streams
in Southeastern Alaska are subject to the maritime influence dis-
cussed in Section 4. While flood peaks do occur in May and June due
to snowmelt runoff, the annual peaks generally center around the month
of September and are a result of intense fall rains. Figure 6 shows
mean monthly and annual discharge data for Crater Creek near Juneau
for the period of record from 1913 to 1933. Normally about 80 percent
of the annual runoff occurs during the six-month period from May
through October. In general, there is very little soil over the under-
lying rock in the area, hence, the major component of runoff is sur-
face flow with some subsurface flow and almost no ground water or
base flow. Therefore, except for glacial melt during dry spells,
the flow in small surface water streams becomes exceedingly low.
Average monthly volumes and their respective percentages of the
annual volume for Crater Creek at the lake outlet are given below:
Crater Creek
Month Average Runoff In Acre-Feet Percent of
January 2,920 2
February 1,810 1
March 1,670 1
April 2,400 2
May 8,610 6
June 20,100 14
July 28,600 19
August 29,800 21
September 23,600 16
October 15,200 11
November 6,990 5
December 2,890 2
Total Average Annual -----Period of Record 144,590
Annual
5.02 GLACIAL AND PERMANENT SNOWFIELD EFFECTS. Glaciers and permanent
snowfields have a stabilizing effect on the variance of runoff from
one year to the next. During a cool summer accompanied by cloudy skies
and high precipitation, the runoff from rainfall is high and the run-
off from gla~ial melt and snowmelt is low, while during a hot, dry
summer the accelerated glacial melt and snownlelt tends to compensate
for the lack of rain. Figure 8 shmvs the extent and location of the
glaciers and permanent snowfields in the Crater Lake basin.
5.03 RUNOFF. Relative to other rivers in the State, the Crater
Creek and Long River streamflow records are quite long, extending back
intermittently to 1913. There are 26 years (1916-1924, 1928-1932,
1952-1963) of streamflow records for Long River and 12 years (1914-1920,
1928-1932) of streamflow records for Crater Creek. The two streams,
Long River and Crater Creek, drain adjacent basins of comparable size,
both of which have permanent snm.,fields and glaciers contributing
to the runoff. Also, both have generally comparable weather conditions.
The lake storage effect is similar for Crater and Long Lake basins.
Stream gaging stations for both 'i)asi:ls are shown on Figure 8.
5.04 STREAMFLOW CORRELATIONS. Hont:l1y flows in Crater Creek 'were
correlated with montll flows fo~ the same months at Long River when
the records for both sites were available. On the average there were
about 13 monthly values at both stations on which to base the corre-
lations. Linear regression analyses were made to determine the monthly
relationships between Crater Creek and Long River. A separate re-
gression analysis was made for each month and an equation was developed
using the log of the average monthly flows in c.f.s. Figure 9 shows
the derived equations, correlation coefficients, standard error of
estimates and a graphical relationship between months. Using the
derived monthly equations, average monthly flows were computed for
the gaging station on Crater Creek, which has a drainage area of 11.4
square miles. This was done to fill the missing record on Crater
Creek from 1913 to 1.970. The gage on Crater Creek was located 100 feet
downstream from the lake outlet; therefore, it was assumed that the
volume of outflow was equal to the net inflow. The high degree of
correlation between Crater Creek and Long River is expected since
they have contiguous drainage areas. The average correlation coefficient
(i) is .89 and the standard error is estimate is .076. These values
indicate the high degree of reliability of the regression analyses
results. Figure 5 t;hmvs the flows for Crater Creek as extended by
cor~elation from 1913 to 1970. Crater Creek streamflows developed
from the correlation studies were used in the sequential routing for
the power studieG presented in Design Memorandum No.2, Snettisham
Project, Alaska.
5.05 PEAK DISCHARGES. Crater Creek normally has high flows in late
spring and early summer due to a combination of rainfall runoff aud
snowmelt. The magn~tude of these high flows is primarily dependent
upon two conditions (1) melt during clear weather and (2) melt
during rain on snow. A large snowpack over the basin will give a
large volume of runoff during the spring; however, if the temperatures
increase gradually, caw>ing a moderate rate I)f snowmelt, and extreme
rainfall does not occur, peak discharge rates will not be except~onally
high. If the early spring is colder than normal and then a sevel'e
temperature sequence occur.s for a prolonged period accompanied by rain-
fall, the flood peak wi:] be extremely high, with the duration of high
flows primari 1y dependeut l'pun the total snowpack. Rain floods pro-
duce the highest: fall C:ischcnges and genel"ally occur between late
July and late October. These flo)d peaks are quite sharp due to the
fast runoff caused by the steepness of the drainage basin and the
low infiltration loss. Figure 7 shows the recorded peak discharges
for Crater Creek.
5.06 SPILLWAy DESIGN FLOOD. Because of the nature of the project and
the fact that there is GO d~velGpment along Crater Creek between Crater
Lake. and tide\.ater, <1 highly refined calculation of spillway design
peak discharge was not needed. however, a peak discharge vIES estimated
for Crater Lake based on the spillway design discharge computed for
Long Lake and the maximum annual runoff relationship Ichich exists
between Long and Crater Lakes. Based on this relationship the peak
design descharge for Crater Lake wou:d be 10,500 c.~.s.
5.07 DISC}l.ARGE FREQUENCIES. Annual peak discharge frequencie~ are
not pertinent because of the nature of the development proposed, the
regulation effects of the lake, the large existing chanuel capacity,
and the lack of development in the area. Annual volume frequencies
do have a bearing on the power generation of the project. These
values are:
Crater Creek at Crater Lake Outlet
Drainage Area = 11.4 sq. miles
Recurrence Interval
in Years
1
2
5
10
20
50
100
200
Annual Volume in
Acre .. Feet ------~-----
104,000
139,000
1.52,000
161,000
L69, (lOO
l"i I) , ueo
Hl6,U0(1
1%,000
5.08 SEDl~,NTATION. A relocaticn of sediments Has cL.;elved '.>ril'.;ll LUili;
Lake 'vas Gra,vn down to elevation 680 for constnlctin;J of tlwJoHcr tUll!leL
At the 1m. water level, much of the accumulated silt in the .1C"LV'::
storage area slid away or was washed from the steep SiOP8S of ··h·.: aelive
storage area and ,ms transpo,:ted to ehe dead ::t:Ol',H"P ; ~e.l 0 r
reservoir. A similar exchange of sediments bet'wee1, the acUv·c. c"IYr,Ji~t'
arcas and the dead storage areas is expected t03ke Iliace regularily
in both era ter and Long Lakes as they are drawn down near \Hi ni.retum
operating depths. Thus, a gain in active storage at ~e expense of
dead storage is expected during the early years of project opalation.
Since Crater Lake is confined by walls of quartz dioriLe, it is
anticipated there will be almost no erosion of the reservoir banKS
once the accumulated sediments have been transported from the active
to the dead storage area.
5.09 No data is presently available concerning sediment loads carried
by streams tributary to Crater Lake. The streams are predominate11
glacial and carry suspended sediment and bed loads. Because o~ the
lack of data on the actual sediment ioad carried into Crater Lake,
it is not possible to compute the annual stora;~e depletion by \'.i.rect
methods: however, a reasonable estimate has been made by indirect
methods, The results are presented in Design HeuoranJU1l1 No.7.
5-3
Sedimentation data has been coll~rted intermittently for Long River
above Long Lake since 1967. It is expected that Crater Creek above
Crater Lake would show a similar trend in sedimentation transporl to
that exhibited by Long River above Long Lake at Station 15-0310.
This data is presented in Figure 4, but is not sufficiently complete
for the high flow periods to support sedimentation calculations for
Crater Lake. The need for establishing sedimentation ranges will be
determined by the operating agency.
5.10 ICE STIJDIES. lee thickness measurements have been made at
Crater Lake, and the results of these measurements are presented
below. Two probings were made about 100 feet apart on Crater Lake
by Corps of Engineers personnel on 22 February 1973.
Probe Number One
O. 0 -1. 5 fee t
1. 5 -4. 5 fee t
4.5 -5.3 feet
Probe Number Two
o . 0 -1. 5 fee t
1.5 -4.5 feet
4.5 -6.3 feet
Dry Snow
Wet Slush
Ice
It is believed that the saturated upper layer of snow is caused by the
depression of the original ice layer by the weight of subseque-:1t snow-
fall. This allows lake water to overflow onto the original ice surface.
The overflow water then freezes and the ice process is repeated. This
ice cover will have no significant effect on project operations due
to the depth at which the intake will be located.
5.11 Experience at Long Lake shows that, as the lake approaches
minimum pool level, the flow of vJarmer water to the outlet tunnel
melts the ice near the outlet, opening an area of ice free water.
The minimum Crater Lake level of 820 will be sufficiently above the
tunnel entrance to prevent floating ice from being drawn into the
tunnel.
5.12 HYDROMETEOROLOGICAL DATA COLLECTION. A reservoir stage recorder
will be installed in the Crater Lake gate structure. Both a bubbler
type, and a pressure transducer are presently being considered. It
is planned to have a pipe from the gate structure to the lake to
obtain lake head unaffected by flow in the power tunnel.
5.13 Climatological data will be collected in the vicinity of the
camp area. The preliminary installation of a standard eight-inch
rain gage and maximum-minimum thermometers was completed in September
1964. This equipment was replaced with the permanent installation,
including recording equipment in October 1972. A climatological
station will not be installed in the Crater Lake basin at this time.
The present need for the data does not justi~ the expense of installa-
tion and maintenance.
5.14 The snowpack in the area tributary to the reservoir will con-
tinue to be meaiill-cc:d. by the U. S. Soil Conservation Service sampling
technique. If a satisfactory location is available near the gate
structure, a snow pillow and recorder will be installed in the basin
and data collected at the snow pillow for use in future analysis of
snowfall and runoff. The installation of telemetry equipment on the
snow pillow is not necessary at this time and will be deferred until
such time as the operating agency determines that snow water equivalent
data on a day-to-day basis is necessary to insure efficient utilization
of the project water resources. This is not expected until the area
power demand approaches the capacity of the project.
5.15 Telemetry and control features will be provided for Crater Lake
similar to those provided for Long Lake. Data will be transmitted
to the powerhouse as encoded signals on hard wire communications
cables attached to the overhead electric distribution pole line. A
level recorder on the powerhouse SG panel will indicate both Long and
Crater Lake stages.
5-5
SECTION 6 -GEi'lERAL GEOLOGY AND SITE INVESTIGATiON
6.01 iN~R0nUCII0N. Most of the g~ographical and regional geologic;ll seltings
for th;-~S;;tLisham Project hils heen submitLed in previous design Il\p\Iloriinda,
[wmely DH 01, 7, and 13. The addition of five C:1t'C bori'lgs, unden,i1ler con-
tours in chc m'E"i' oC the select(,d tbP s~te, :lIld some ge<llogic surface 11IilP-
ping vnIL he included ill Ihis rc-pol:t.
6.02 PROJECT SITE GEOLOGY 0 The predominant rocks which occur within the
immediat.e area of the SnettLsham Project consist of quartz diorite, gneiss,
and some J,()cillized phases of biotite schist which all occur in a somewhat
interwoven illld random distribution pattern throughout the main rock body
at the site. Due to recent glacial scour in this area and resultant re-
mov3l of most weathered surface rock materials, the majority of the bedrock
wh~ch will ~e encountered by proposed engineering structures will be rela-
tively fresh, dense and of durable quality. Localized exceptions to this
will definitely occur, chiefly in association with the major shear zones
which occur in the area. These relatively narrow zones in which the rock
has been (:[ushpd aDd broken have allowed much edsier access co percolating
ground wClter" and these waters have imposed a substantL1l1y higher degree
olf chemical alteration on the sheared rock than is to be found in other non-
disturbed portions of the generaL rock body. Granitic type rocks, such
as qUilr:z diorite and gneiss, contain high percentages of the felspar min-
era 1 pLlgiocLse, which upon chemicCil decomposition by ground waters wi th
dissolved c:lrboll dioxide (carbonic acid), yield the cLay mil1ci.'al kaolln.
Because of the overall lesser quality rock materials ilss()L'LIt:(~d with the
larger shear zones and, to some extent, the systems of closelY spaced
joint~\ exact locations and orientations of all such pertinent rock struc-
tural features, with respect to the locations of proposed engineering
structures is ;C'. factor of considerable design import,3nce. (See geologic
maps, Pldtes 3 and 4.)
6. 03 SE.LS~1TC CONSIDERATIONS. Hh He the presence () £ mai ur fatc It zones does
testify to the existence of seismic activity in this immediate a:Ced during
the geologic past, it is gene:::ally believed that all such movemer,ts along
these [;Cll;it;, in·e sufficiently remote in geologic Lirle ilS tu preclude concern
of [heir furcLer 3.djustments duriHg the life of the project. To the extent
poss~ble, aLtempts to conhrm this premise have been made ly searching for
obvious offsets in recent glacial or alluvial strata at points where they
cross known major faulls, but thus far no such evidence of recent faulting
activity hat; been found anywhere near the immediate project area. The
proxi:::i Ly (;.f.' the Snettisilam Project to a major zone of crustal weakness
does, how~ver, make it prudenl to design important structures at the pro-
ject for fairly substantial earthquake accelerations. The 1957 seismic
probability map by the Coast and Geodetic Survey and modified by Corps of
EngiEeers, considers the Snetcisham Project as being in Zone III and magni-
tLldes of 6.G and above ,\/Quld be anticipated. Use of Zone III magnitude was
recommended i.L Design MemoramiuIIl No.3 <l:ld approved by higher authority.
6.04 Excepl [or thL Craler Lake Lunnel and penstock, no lmportant struc-
tures will b8 constructed acrOS3 major fault zones. The tunnel will pass
three',:'· t .. !·"
6.05 GEOLOGICAL EXPLORATIONS. The power tunnel alignment for the recom-
mended plan was the result of carefully selecting the best locations, geo-
logically, for the lake tap and the surge tank. Once these two points were
determined and the horizontal and vertical cover was checked to be sure of
enough rock cover, the tunnel ;llignment became fixed [or the purpose of con-
ducting explorations. It was along t~is alignment and location o[ features
that initial geological explorations were conducted during the 1972 field
season. The contract held by Taku Constructors was modified to include
1446 lineal feet of NX core drilling, underwater survey of that portion
of the lake selected for a tap site, and some surface mapping. Those
faults and joints which have been studied in the field, have high angle
dips ranging from 60 to 80 degrees measured from the horizontal. The
geometry of surface traces of these geological structures appear as
straight lines, or nearly so, on aerial photographs, which additionally
supports the fact that the structures are steeply dipping. Also, the
information obtained from First and Second faults as well as Glacier Creek
fault, in the Long Lake tunnel, is graphic evidence that they are quite
planar along their dip planes. It is expected that the fracture planes
along the Crater Lake tunnel will also be planar. Cliffside fault, Sta 10+20,
is exposed near lake level and is considered a prominent geological feature.
This fault was not sampled at depth by drilling. The next major structure
is Hilltop fault, which is exposed on the surface at Sta 12+50. Because
erosion processes have removed rock from both sides of the fault plane, an
acceptable area could not be located for a dip measurement. Studies of
the core of DRI02 indicate that a fault was encountered between 267.4 and
313.5 ft. of depth. Core recovered from the fault zone is very closely
broken into small pieces ranging from 0.1 ft. to 0.4 ft. Most of the core
lengths that are 0.2 to 0.4 ft. long have healed fractures. The only hole
drilled along the mid-portion of the power tunnel, DR 101, was located to
investigate the rock conditions of the Junction fault. Some thirteen feet
of closely broken core was recovered between 160 and 173 feet. While this
small amount of broken rock is thought to represent the Junction fault, it
is expected that this reach of the tunnel will have some 90 ft. or more of
blocky rock which will require some kind of support. The rest of the core
appears to be normally jointed for the area. Drill hole DR 99 was located
in an area selected for the surge tank and drilled to a depth of 350 feet.
Core recovery was excellent and no evidence of faulting was observed in
the core. The site for the surge tank was later moved some 135 ft. up the
tunnel for penstock and rock trap design considerations. Additional
drilling was done along the power tunnel alignment to investigate certain
faults, however, the data is not available for this memorandum.
6.06 The 1973 field season has been very successful from the standpoint
of mapping the surface geology along the route of the power tunnel. Many
of the lineament features shown on previous maps were the result of studies
of aerial photographs. Much of the effort of the field season was spent
in ground truthing the previous photographic studies. Geologic structures
were mapped by the tape and traverse method and where accurately located
where they cross the center line. The mountain side is so steep and rough
and covered with dense trees and thick underbrush that clearing the center
line of brush was re(JUired in order to SU1"Vey and stake the alignment
every 100 feet. Clearing the center line made a tremendous impact on the
field work.. Brushing out a narrow swath permitted sufficient visibility
which enabled many geologic features to be observed and recognized for the
first time" Two fa.ults of major importance were discovered only after the
centerline was brushed out when on several previous traverses of the area
they had not been observed. Five major faults have now been identified.
Beginning at the lake and progressing up stationing towards the pen3tock,
they are: Cliffside, Hilltop, Junction, Tlingit and Tsimpsian. (See
plates 3 and 4). Field studies proved that the feature previously identified
as "Cross Country Fault" is indeed a minor joint and therefore has been
deleted from the geologic map. The two new faults which were discovered,
the Tlingit and Tsimpsian, cross the tunnel alignment at stations 51+00
and 60+00 respectively.
6.07 OTHER TYPES OF INVESTIGATIONS. The above subsurface explorations
have been augmented by geologic mapping, underwater survey and office
studies of aerial photographs. Results of these investigations are in-
cluded where appropriate in this memorandum. Studies of borrow areas
for concrete aggregates have been done previously and the materials from
area 'one' and area 'two' have been used in the Long Lake construction
phase. Future investigations will include re-examining borrow areas 'one'
and 'two' with future concrete requirements in mind, additional NX borings
along the power tunnel alignment and the surge tank area, lead line survey
to varify underwater contours, unden~ater TV survey of the rock at the tap
site will be made from a small 2 man submersible (submarine), and additional
surface mapping of fractures, faults, and joints.
6-3
SECTION 7 -G_EOLOGICAL EVALUATION OF WATER WAYS
7.01 GENERAL BEDROCK CHARACTER. Explorations and studies conducted to
date indicate the quartz diorite bedrock, which will be encountered by
the power tunnel, penstock tunnel, surge tank, shaft, will be generally
of good to excellent quality. As mentioned in Section 6, localized
exceptions to this general premise will definitely occur at known major
fault zones. These zones of ~ighly broken and weathered rock have been
identified with relative accuracy, as to their position along the tunnel
alignment, as a result of field mapping of the rock structures above tunnel
grade and studying of aerial photographs. To the extent possible, all
major structures have been located or aligned so as to minimize, if not
completely avoid, known faults or closely spaced joint systems in the
rock.
7.02 POWER TUNNEL FAULTS. The power tunnel will pass through five prominent
and several minor fault zones, see paragraph 6.06 and Plates 3 and 4.
Unlike the Long Lake tunnel, Crater Lake tunnel will pass through most of
the fractures at less favorable angles. The acute angles range from
20 to 30 degrees. Also, there are considerably more fractures along the
alignment which have visible surface expressions. Office studies of these
fractures are not complete enough to determine the degree of impact of
these features on the design and construction problems of the tunneL
Studies to date indicate an order of magnitude to be; (1) Junction, (2)
Cliffside, (3) Hilltop, (4) Tsimpsian and (5) Tlingit.
7.03 NATURE OF FAULT ZONES. The central portions, or "crush zones", in
each of these faults are expected to be characterized by closely broken,
mylonitized, and altered rock, intermixed with definite lenses or stringers
of plastic fault gouge. Adjacent to each ceutral crush zone are border
phases of less severly broken or altered fresh rock extending outwards to
the mass of rock. More extensive remedial measures are therefore anticipated
in connection with tunneling operations through these particular five
faults; however, experience in the Long Lake tunnel was that the -:ock in
the fault zones was sufficiently strong and did not require SUppOl::" of any
kind while excavating. While we might be hopeful for a similar condition
in the Crater Lake tunnel, consideration has to be given to rock conditions
which are less then ideal; therefore, the same consideration will be
given this tunnel as was given to Long Lake tunnel in so far as design
assumptions for tunnel support are concerned. An exploratoLY "guide" hole
will be drilled in advance of the tunnel heading on approaching iiay of the
major fault zones to explore for the occurrence of high pressure £lmvs of
water or unfavorable ground conditions. Drilling of this guide hole will
be phased with the blast hole drilling, shooting, and muck removal operations.
7.04 OTHER REMEDIAL HEASURES. Generally, good rock condLtions are ex-
pected throughout a major part of the tunneling operations. Overbreak
and running ground are not inherent qualities of this rock, nor is the
tunnel expected to be wet. Remedial treatment will be required where
rock conditions are unsatisfactory. Rock bolts, concrete lining, wire
mesh, shotcrete and grouting will, by and large, be used to take care of
all but the most difficult conditions. It is not anticipated that an
appreciable number vf, if any, sets wil~ be required, and that they will
be limited principally to where rock conditions are closely associated
wi th faulting. Loni~ Lake tunnel die. not require any support in the form
of sets and, likewise, it is believed that Crater Lake tunnel will not
requi.re set support; however, the contract will require five steel sets
to be on site as a precautionary and expedient measure.
7.05 ROCK REINIQ..RCFJ:-1ENT. Pattern rock bolting wi 11 be done in those
areas of the tunnel where the frequency, dip and strike of fractures re-
quires a pattern of bolts for reinforcement, Elsewhere, spot boL:ing
\vill be used to provide safety or to supplement pattern bolts where un-
favorable geologic conditions exist. The pattern design will be based
on engineering principles and rock behavior. Bolt lengths will be varied
to prevent a plane of weakness in ':he Cl~own 0 f the tunnel. When required,
rock bolts ,,'ill be inf,talled irmnediC'.tely after tunnel excavation to mini-
mize stress relief, overbreakage and rock falls. Approximately 4,200
rock bolts will be required fo;' the power tunnel and appurtenant struc-
tures. Instrumentation and testing will be restricted to rock nO-Lt
deformeters and pull tests of regular rock bolts. In the event o~ latent
geological condiUons, additional instrumentation will be consicle::ed, and
only chen after careful evaluation of the overall situation. This is not
to imply a negative attitude towards instrumentation. Rather it implies
a carefully evaluated need for instrumentation, the use of data and, of
course, a means of monitoring or collecting the data.
7.06 CONCRETE LINING. Concrete lining wi 11 be required for a L leas t
tlve major faults, Cliffside, Hilltop, Junction, Tlingit and Tsimpsian.
Cliffside and Hilltop faults are fairly close together, some 130 ~t. at
tunnel level, and will probably have. continuous concrete lining \vhich will
also extend 100 ft. dmVl1stream of the gates. The next fault which wi.ll
require lining is Junction fault. Studies of aerial photographs indicate
that !:here are several lineaments passing through the area and they cross
one o~~her. R3ther extensive lining .i_s expected through these fau· ... ts. ;::nD-
Linll011S lining is ex?ccted between statiO:l 2~+65 and station 31+20. Tile
nex, major geolotcic structure which is expected to receive concrete lilling
is Tlingit fault at station 61+00. The surface trace of this [<:'-uLt is
reflected as a shallow trench like <iepression some 70 feet wide. While
thi~; s truc ture has 2. sub stan t ia1 wid th at the sur face the need for ac tua 1
concrete lining would most lil<ely be in the o:.der of 120 feet or the','e
about with the resL of the broken reck being sllpported by roc~ bolts.
Tsimpsian fault at staL_on 60+00 is some\"hat 5.Lmilar to the Tlingit fault
in that the surface expression is that of a trench only '.1arrowel-. Surface
conditions indicate d,e Tsimpsian fault to have a more clusely broken zone
of fault gouge. An estimated 70 feet of concrete lining is assigned to
this fault.
7.07 OTHER Ex..DUJR.I\TIQ~§'o In addi. tion to the sur face geology along the
tunnel alignment five NX borjngs have been in ~)rogress during the late
summer and fall of 1973. One boring 1.S to explore the rock in which the
surge tank will be !-u(ltltn;ci:ed. tile other fouY.' borings are to Bt_udy Junction,
Tlingi t and Tsimpsian fa'.llt s. Again, only preliminary information in limited
amounts has been made available by the contractor. The penstock alignment
will not be drilled because of its close proximity to the existing Long
Lake penstock. Geological jata obtained from the existing penstock is
extrapolated and projected to the Crater Lake penstock and a surface traverse
for geologic data will be made; therefore, the high cost of exploratory
drilling is not justified. Also, the reader is reminded that the penstock,
in addition to being buried in rock, is a steel pipe encased in concrete.
An estimated 940 lineal feet of concrete lining, most of which will be
12 inches thick, will be required to stabilize the tunnel ,,,alls across
faults and fractures.
7.08 PENSTOCK AND ACCESS ADIT. For the purpose of this design memorandum,
it is planned that rock bolting will be performed in the penstock tunnel
and access adit in the same basic concept as outlined for the tunnel in
paragraph 7.05. Overbreak conditions are generally similar to those dis-
cussed in paragraph 7.04. 'Because of its closeness to the Long Lake pen-
utock, much valuable geological information can be projected to thc new
penstock with a high degree of reliability.
7.09 GEOLOGY OF OTHER WATERWAYS FEATURES. As stated in paragrapL 7.01,
current knowledge of the general project site geology has enabled many of
the project features to be advantageously placed in specific areas of
highly competent granitic bedrock. Major structures such as the power
tunnel and penstock must accept zones of lesser quality rock because of
their relatively fixed positions within the project scheme. (Plates 3
and 4) Remedial treatment is discussed in paragraph 7.05.
7.10 LAKE TAP AREA. Probably the most important single area, gee,logically,
of the project is the mass of rock iil. which the rock trap wi.ll be con-
str.ucted and through which the lake 'will be pierced. The site ,Jaf: ori.g-
inally selected in an area having the most favorable geology based on
l.imi ted Eiel.d work and studies of aerial photogrCiphs. ALlditioltLll, but
preliminary, informatiull obtained from the 1973 field work has served Lo
verify the 1.ocation as being the best. A two man submarine \las used by
Lhe COEtractor to investigate the bottom of the lake. Video tapes \vcre
made of three traverses of the tap area starting some 250 feet deep and
moving shoreward, up contour, to where they emerged at the surface near
the shore line. Very fine grained sediment covered the rock :0 m.;kward
depths ranging up to 3 or L~ feet. An estimate of overburden depth wa~;
made by letting the submarine penetrate the overburden materia] unLil the
bottom of the submarine struck rock. Assuming the attitude of the sub-
marine was level the silt was estimated to be some 3 to it feeL deep in
t.hose few places investigated in this manner. Also, in the vi.cin~ty of
the 145 fooL contour (depth below su:-face) a mass of trees \V'as encountered.
This horizon of trees appeared in all traverses. The rather broad area
i.nvestigated with the submarine has encountered the debr:Ls of trees at
generally the same depth and across most of the rock face of thL! eilst end
of the lake. At this time, and without benefit of office studies, it
appears that both sediment anG the debris of trees are inescapable and
will have to be dealt with.
}-3
7.11 DAM AREA. A small concrete dam located across the lake outlet and Ll
separate diversion tunnel has been studied. The rock in the dam site
ridge is broken by a least three, and possibly four, high angle faults
which are subparalleled to the ridge and cross the creek at right angles.
Also, the deep trench through which the lake discharges is an expression
of a major fault.
7.12 The faults which cross the creek trend N 27 oE, dip 75 0 to 800 SE,
and are spaced about 70 feet apart. The fault which forms the trench in
which the creek flows trends N 50OW. The dip is unknown.
7.13 Rock in which the foundation of the dam would be constructed is
expected to be unduely broken with shattering adjacent to faults, especially
the fault which parallels the creek. Over excavation and remedial foundation
treatment is expected to be somewhat greater because of the spacing and
orientation of the faults in such a relatively small area. Many of the
problems encountered during the study of the Long Lake outlet are expected
at this outlet. For geologic reasons a dam is not recommended.
7.14 The diversion tunnel, some 1,670 feet long, is located into the
mountain sufficient distance away from the creek to be out of the influence
of the Crater Creek fault. Where the NE striking faults pass through the
diversion tunnel, dental treatment, similar to that which was done in the
Long Lake diversion tunnel, would be required.
SECTION 8 -HYDRAULIC DESIGN
8.01 GENER..<\L. The hydraulic des ign of the Crater Lake features is
similar to those done for the Long Lake phase of the Snettisham Project,
as presented in feature Design Memorandum No. 10, "Power Tunnel, Surge
Tank and Penstoc~', Supplement No. 1 to Design Memorandum No. 10. The
hydraulic design herein is based on the features as determined by geo-
logic and structural considerations.
8.02 ENERGY LOSSES.
a. General. Head losses in conduits are primarily caused by the
frictional resistance to flow. Additional losses result from trashrack
interferences, entrance contractions, bends within the conduit, con-
tractions and expansions from lining lengths and gate structure, and
other interferences in the conduits. Each feature producing a hydraulic
loss was given a loss coefficient (k) to be used in the equation [or
head loss. All loss coefficients were totaled [or all project features
from the intake to the spherical valve to provide the total head loss
for any flow.
b. Frictional Losses. Based on experience in Norway by the C. F.
Gr~ner finl and construction perfonnance at the Snettisham-Long Lake
power tunnel, a Manning's "n" value of 0.028 was used for the expected
frictional resistance in the Crater Lake tunnel. Theoretical COITlputa-
tions, using the Von Karman-Prandt1 equation for turbulent
flow in rough pipes and estimating the height of roughness in the power
tunnel, produce similar results as follows:
Maximum Roughness (k) = 1 foot
Expected Roughness (k) = 0.5 foot
Minimum Roughness (k) = 0.25 foot
Converting absolute roughness (k) to Darcy's friction factor (f) by
the Von Karman-Prandt1 equation:
r O
k + 1. 74
where rO= radius of the conduit
k = absolute roughness height
The values of Darcy's friction factor (f) is then converted to Hanning's
"n" by
f
where d = diameter of the conduit
The resulting values o[ Manning's "n" then become
Maximum "n" = 0.034
Expected "n" == 0.028
Minimum "n" == 0.025
c. Other Losses. All other hydraulic losses were handled in a
similar manner. Each feature was analyzed for the type of geometry
expected and a value of maximum, expected, and minimum absolute rough-
ness was given. The loss of head at the intake to the power tunnel
was considered comparable to the loss in a short submerged tube. Losses
due to curves in the conduit alignment were related to experimental data
on bend losses in smaller pipes. Transition losses in the conduit due
to lengths of concrete lining and expansion and contraction of features
such as rock traps, were estimated from experimental data given in
standard hydraulic texts. The trashrack loss was estimated from pre-
liminary sizing of the structural members. The total hydraulic losses
are shown on Figure 16.
8.03 ECONOMIC SIZING OF POWER TUNNEL AND PENSTOCK. The unlined power
tunnel and penstock sizes were selected by the following procedure:
a. The Federal investment costs were estimated for several tunnel
and penstock diameters. For the power tunnel, the costs were based on
an unlined modified horseshoe tunnel. The tunnel considered has an
unlined length of 5,300 feet and 825 feet of concrete lining. These
estimated lengths are based on preliminary geological information avail-
able and experience with the Long Lake tunnel. The penstock is steel
lined.
b. Hydraulic losses were estimated for the several considered
diameters of tunnels and penstocks.
c. Hydraulic losses were converted to equivalent average energy
losses based on average plant factor operation. The annual value of
the energy losses (See Section 24) was converted to a present worth
basis using 3-1/8 percent and a 95 year life. A 95 year life was used
because Crater Lake power comes on line 5 years after Snettisham Project
power comes on line.
d. The investment costs were ~dded to present worths of the hydrau-
lic losses for total comparative costs. The results are shown in curve
form, Figure 15.
8.04 The Federal investment costs were estimated for tunnel excavation
using rail and rubber tired equipment. A tunnel 11 feet wide and 11
feet high and a penstock 6 feet in diameter were selected as the most
economical size.
8.05 SURGE TAt-.TK. The Snettisham Project will be serving an isolated
load since no other large generation or transmission facilities are
available for interconnection. Such operation requires a plant which
has capahility for r~pid load pickup, rapid load rejection, and in-
herent stabj lity under load changes, A surge tcmk providf's .1 SOllrll'
of water tc flllfi 11 the function of allowing rapid load pickup. 1'l'r·-
formance of the system wi.thout a surge tank on both load rejection and
load acceptar..ce, combir..ed 'dth the stringent operating requirements,
indicate the surge tank is required for the Crater Lake power facilities.
8.06 The Thoma Formula (F = AL ..... 2gCH) is a standard tool for selecting
the first approximation of surge tank diameters to meet stability re-
quirements. The Thoma Formula is designed to provide a tank area (F)
which will provide borderline stability under a small load change,
assuming turbine efficiency is constant. That is, the surges will
neither increaf>e nor decrease in amplitude as a function of time. Stand-
ard practice is to increase the Thoma diameter 50 percent. The Thoma
diameter plus 50 percent for the Crater Lake surge tank is 8 feet.
Future studies will consider the advisability of increasing this diameter,
considering construction feasibility and reduction in surge amplit"des.
The detailed analysis for the surge tank design will be presented in a
design analysis Lo be furnished at a later date. The surge tank for
Crater Lake will be of the restrictive orifice type. The orifice, which
will provide additional headloss during surge action, will b0 located
in a horizonca1 riser or drift, connected to the rock trap. The orifice
was designed for the pressure head elevation at the orifice at time t '" a
to equal the surge tank water surface at the quarter cycle. 1~~ or~fice
will be approximately 4 feet in diameter.
8. a 7 The minimum and max imum surge elevations were approx im;, teo. tLrough
use of the Calame-Gaden and R. D. Johnson Curves. The minimulll SU1·~.C \.,ras
based on turb ine load acceptance at the minimum power pool ,vleh mHXI.mum
hydraulic losses. The elevation of the minimum surge (elevC1i:i.on 752)
vias used :::0 set the invert elevation of the surge tank. The n.;]-imum
surge l.;as r'ct.2nnined to define the height of surge tank and ,.h. cl~:1amic
pressures ,y, the penstock. The maximum surge (elevation 1070: is baSEd
on turbine load rejection at maxinum power pool with '1linimurr. hy3raulic
losses.
8.08 WATER HAt'1MER ANALYSIS. --_. __ ._-
a. MaxilfHlID water p.: __ essure gradient in the penstock due to ' .. Inter ham-
mer was determined by use of the Allievi cba.rts. The Allie'J'; CbelL
values were based on maximum pool elevat ion, maximum net tur·)ine r-,e:'1':
with complete load rejection with a valve closing time of 5 seconds.
b. The internal pressure l.vithin the penstock due to water :u:mU11er
is assumed [0 vary in il straight line from the maximum surge at tilA
surge tanK to the maximum water hammer pressure at the spherilClJ. value.
See Plate 11 for a graphical presentation of the intern1l1 Dress"n~ in
th,.: Dell~,j":
c. For final analysis of surge and water hammer pressures the
Alaska District will use MIT computer program "Hydro-Power Plant
Transcients" developed for use by Missouri River Division (MRD) and
used in designing the Long Lake Surge Tank and Penstock.
SECTION 9 -TURBINE SELECTION
9.01 GENER..~. A study was made for the Alaska District by the Hydro-
Electric Design Branch, North Pacific Division, to determine if a
larger turbine unit could be used in the existing Snettisham power-
house blockout than originally provided for. Based on the results
of that study (Exhibit 3) a 27 MW (30 MVA) unit is considered to be
the largest U\1(t that can be installed in the available space. Al-
though the spiral case for that unit is slightly larger than those for
the Long Lake units, the increased size should not create any problems.
It is recommended that the 27 MW (nameplate) unit be selected.
9.02 NET TURBINE HEADS. The net turbine heads were computed from the
application of the following basic hydropower formula:
where:
KW := Q x H x plant efficiency in percent
11.8
KW = continuous power in kilowatts
Q regulated flow in c.f.s.
H = net head in feet
An overall plant efficiency of 85 percent was assumed for this Gtudy.
The formula then becomes:
KW = ~ H x 0.85 '= QH 0.072
11.8
Preliminary studies indicate that a 27,000 KW nameplate unit
largest that can be accomodated in the existing power planL.
i~;.:he
Th(-.refore,
H P ,000 KW
net 0.072 Q
From the above formula the maximun:, average, and minimum turb in" h.eads
were computed.
9.03 The maximum turbine head was based on the maximum pool e1e'Jation
of 1,022 feet, a minimum taibvater elevation and the expected hydt'.'.lulic
losses. The average turbine head was based on the average power pool
of 966 feet, average tailwater and expected hydraulic losses. The
critical turbine head is based on the minimum power pool of 132 1 feet,
maximum tailwater and expected hydraulic losses. The following values
are derived from the above criteria based on an Il-foot modi.fied
horseshoe power tunnel and a 6-foot diameter penstock.
Maximum Net Head
Averagt:! Net Head
-1
Net Turbine Heads
1,003
941
779
9.04 The preliminary turbine selection shows a small difference in the
values of net heads used because the study was based on a 10-foot
modified horseshoe power tunnel and a 5.5-foot diameter steel penstock.
Subsequent economic analysis shows an II-foot power tunnel and a 6-foot
diameter penstock to be more economical. This change in sizing will
increase the net heads of the turbines by 1 percent at the maximum
head and 5 percent at the critical head. These changes will be re-
flected in the design analysis.
SECTION 10 -POWER CONDUIT
10.01 GENERAL. The power conduit includes a lake tap and related
rock trap, an unlined section of power tunnel leading to the gate
structure, an underground gate structure, another section of unlined
power tunnel, the rock trap, surge tank, penstock, and pertinent
features. These structures constitute the waterways to transmit Crater
Lake water to the powerhouse. Their locations and relationships to
each other and to the remainder of the project are shown on Plate 2.
10.02 POWER TUNNEL. The plan and profile of the power tunnel are
shown on Plate 8. The length will be approximately 5,930 feet from
the entrance at the lake, through the rock trap and gate structure to
the beginning of the steel penstock. The invert elevation will be
800 at the lake and 746 at the surge tank with the tunnel floor slop-
ing down at one half foot per 100 feet toward the penstock. The tunnel
will be a modified horseshoe, essentially unlined, excavated in rock,
11 feet wide and 11 feet high.
10.03 A reinforced concrete lining will be provided in those sections
of the tunnel where poor rock conditions are encountered, as dis-
cussed in paragraph 7.07. (Plate 9.) This lining will be designed
to withstand a pressurehead in excess of the maximum pool level.
10.04 Supplement No. 1 to Design Memorandum No. 10, "Power Tunnel,
Surge Tank, and Penstock," Snettisham project, reported on the feasibil-
ity of an unlined power tunnel and related features for the Long Lake
power tunnel, including a cost comparisOn with the lined tunnel. The
conditions for the Crater Lake power tunnel are similar. Therefore,
;In unlined tunnel is recommended, without a comparative study of a
fully lined tunnel, because the findings reported in Supplement 1 to
Design Memorandum 10 are considered valid for the Crater Lake power
tunnel.
10.05 The criteria for determining where the pOvler tunnel w"il.l he
lined, when not required because of rock conditions discussed i~ para-
graph 7.07, and where the steel penstock lining commences a.re illustrated
on Plate 8 are are:
a. Minimum rock cover, in feet, vertically above any point in
the unlined tunnel shall tle equal to eight-tenths of the maxi.mum
dynamic pressurehead, in feet, to which the tunnel shall be subjected
at the tunnel station;
b. The minimum horizonta 1 distance, in feet, to the rock sur face
at any point in the unlined tunnel shall be equal to one hundred-
fifty percent of the maxim~m dynamic pressurehead, in feet, to lJhich
the tunnel shall be subjected at that tunnel station;
c. The minimum distance to the rock surface, in feet, at d point
to the side of the unlined tunnel above the tunnel elevation s~all
be equal to the maximum static pressurehead, in feet, to which the
tunnel shall be subjected at that tunnel station, measured horizontally,
and equal to six-tenths of the may:imum static pressurehead, in feet,
to which the tunnel shall be subj<!cted at that tunnel station, measured
vertically.
d. The m~n~mum rock cover aL any point above and to the side of
the unlined tunnel shall not be less than that described by straight
lines connecting the three points established by the criteria in a,
b, and c above. The power tunne:_ has rock cover in excess a f the
above stated minimum requirements for its entire length upstrea~ of the
steel penstock lining. With pool elevation 1022, the maximum dynamic
head on the power tunnel at the surge tank is to elevation 1070. The
maximum dynamic head in the tunne~ is assumed to vary in the straight
line between the surge tank and the lake level.
10.06 PENSTOCK. The penstock will be 6 feet diameter, steel lined,
encased in concrete (Plate 11). It will be approximately 1,570 feet
long, extending horizontally about 500 feet from the rock trap to
where it will slope downward at a 45 0 angle, leveling off at Elevation
7.5, immediately upstream of the powerhouse valve room wall.
10.07 Dynamic pressure heads vary from 1,070 feet
to 1,360 at the spherical valve. The steel lining
to withstand the maximum internal dynamic pressure
of the following criteria.
at the surge tank
will be designed
and satisfying all
a. With steel stresses limited to one-quarter of the ultimate
strength, assuming support is provided by the concrete and rock.
b. With maximum steel stresf;ed limited to 50% of ultimate
strength or 80% of yield strength, wh~chever is the lesser, assJl1ling
no support is provided by the concrete and rock.
The steel lining will also be desLgned to resist buckling with an
equivalent external pressure head, in feet, equal to the distance to
the rock surface immediately abOVE: the penstock with the penstock
unwatered. The minimum steel lin:~ng thickness shall not be less than
3/8 inch to provide stiffness for construction handling and placing.
10.08 The steel penstock extends upstream to the point in the power
tunnel where the minimum rock cov(;r criteria, outlined in parag::aph
8.05 for the unlined power tunnel is satisfied. Minimum rock cover
for the steel penstock shall exceed three times the penstock diameter.
10.09 The tJlpC of steel and thickness will be the subject of a de-
tailed study that will be reported in the design analysis. A p::e-
liminary analysis has indicated ttat ASTM-A537, Class 2 steel, a normal-
izing presure ves 1 quality steel is the mJst economical and the cost
(!stimdLe is based Oil this steel. The Long Lake penstock i~ constructed
uf thi s s c~;e Land ASTH-A5l6, Grad.! 60 steel, both of which wi 11 L>e
'-ncluded iI, Ule detailed study. One hundred percent radiugraphic
l~xamin3 ~:i or, 'j f we Ids Hi 11 be required.
1.0.10 ThL [.'c;LSi:.ur:k e;~cavation, a:; presently envisioned, will b2 a
g foot J-'.3LlLCi.) Ci:::Cll:d;-cross·-seetion tunnel with onc ioot thick
concrete ellCaSe[:1,~llt of the sl":ee~ ·~inei.·. The Long Lake penstock was
~pecified LO have a 10.5 feet diaDete~ excavation with a one iOJC
thick c.Ollcrei.2 eUC2.sement of all 8.5 ':eet diameter penstock, but "TaS
actually consu:uctcd with r. conc:.ete encasement approaching 3 feet
in thicklleGG becauGt:. of the const!'uction techniques and methods elected
by the contractor. This will be considered further in preparation of
the design and a change Pi'oposed, i: justified.
10.11 ~)ENS1~~)CK TPu'\SIIRi~C:. In the recommended plan, a. ~u;' trashrack
with net openinGs of .:" by L~'I :!_s required at the upper Lll'l of the pen-
h tack illi l La lL:" becau:,e () f tlle lake ;. ap and drawdown s ·::l,clne. A f:er
fhe trashn::ck is irw:ai i _ec1 .l<: the lake, the upper half of ttl: . .' crash-
rllck \-,ill b\.~ remo-rt-~<l. '1-'he remain:~Ilg hal f rack will catch any rocks
liloving eJong the bot:to1'1 u·= the pouer ~unnel, retaining th",:l in the
~ock trap ared for Llter removal. Since there will be 3. full trash-
l'ack at the lake eud of the power tunnel to catch flodting materLal,
h half rack i:.i all that is required at the penstock entraclce.
10.12 Tt-;TAKE TRASHRACK. The powe:.: tunnel entrance wi 1 i. be covered
by a Rteel trashrack (Plate 10) designed to withstand R SO foot
differentia!, pressure head and c8:)able of being covered, ],ll a~l emergency,
'.Jith steel stoplogs or a membrane so that the power tunne-. llpscream of
the gate structure can be umqater.od. This rack will have net openings
() : 2" b) 12" The l'e(~()mmendeJ l.qke tap prGcedure dict.ate: l:hat ~h:Ls
trashrack be installed after the ·;.ake tap and initial draWC(MIl ildve
b(~en achieveJ. The iTc:shrack w5_l·. be insralled, usi.ng fl. '.lL :,~, ~(IU~P-
IIlent: (,11 tl1l-; l.Rke ,11'11.· .;_'" tJ1C HaLer ;ourIa,::e is held at +-·lle ,i elL:1/' .j evel.
The lTLlt,h!':l(i.,-\,,'1.-.. not be remuvab~_e and trashrack cle;r:l:.l)rk~l';.l)nS
\olj 11 } e po;c-sible on1.y at lou pool:; utilizing divers and, rj":ltillr.;
cCluipment: i.n trl!; lake. However., (iebris is not expecter[", d
p'oblem lJeC<.ll[;e the i_uJsIlJ~ack niLe be I)n the slope of l', :~-" "vall,
<.pprQ},ilTl,-:~_ely 4:) (!.';6:L"'(~.3, "nd the velocity of flow ~:hl'Ol .1[i;.~ gross
trashrack. ClIca \;c.11 lle.:_imi_i,;ll to bL~t've0.n 2 and 4 f(!.;~~ l';E':U:lJ.
lO.l] The surge: tank will he ,Ill (3 foo!.: diameter vert:· ! -lS;:lg,
\\i·.lined ,-OCt· r:;Iw<c:, ·.·i~;ing ':u '::lw ground "l1lrtflCe (PIa:: .(, "" T.o[1
of this roc1r "hart w~ :.1 be c()nc'~eT:e coven~d. Rock bolt::.: .r·d 0,'1.:'-0') will
IJe inst'111.cci, a8 required. The Long Lake surge tank (:xtellds !3.b·w€ the
ground SU} ~c1ce and har·, El eoncrete cover 't-Jith a steel ·\"cn~. pLIO ~ ~.I.)
prevent STem! dri.Hs and s'lides from co"ering it complc t :.<::1'. '~i ':~e the
required hl·:it;Lt: 0 C surge tallk for Crat,'!r T,dke does no t-'·(':ch~h? ground
l'llrfac:e abolt;, iLl": rl-:e sp.lect,~2. ',oc,'>':·.Ol, tlw concrete ('f.·or!' :;' ))1.'1
t:o prevent: Ul')i'l biocking 0:::-foreigtl material entering the t.:.:.nk. A
10uvf:J: '.>fii 1 De 1)r'rn ri.cect on the Ilounhi 5_1 side to vent the ti.·n~.;:. "
-< . -." .J
10.14 The m~n~mum cover requirements for the unlined power tunnel,
discussed in paragraph 8.05, dictated the upper extent of the steel
lined penstock. The surge tank is located as close to this point
as possible with consideration of the geologic conditions in the area.
10.15 ROCK TRAP AND ACCESS ADIT. The reccmmended concept includes
a rock trap immediately up£tream of the peLstock (Plate 10) with a
floor elevation approximately 6 feet lower than the penstock invert.
The surge tank drift will have an invert elevation approximately 5 feet
above the rock trap floor to prevent rock moving into the surge tank.
The power tunnel access adit location upstream of the rock trap is
influenced by the requirements fo~ the access road. The adit will have
a concrete plug with a steel door on its upstream face designed to
withstand the full dynamic head to elevation 1070. A pipe with a
gate valve will be provided at the adit pl~g invert to drain water
from the rock trap.
10.16 With the power/access tunnel scheme, the access adit will be
located in the same position but will not require a plug. A door will
be provided to exclude animals.
SECTION 11 -GATE STRUCTURE
11. 01 GENERAL. The recommended gate structure is housed in a chamber
in the rock at approximate tunnel Station 13+90, about 750 feet down-
stream from the lake. The location was governed by geologic conditions
and is subject to relocatio:1 after more detdiled study.
11.02 RECOfmENDED STRUCTURE. ThE gate structure will be a concrete
lined chamber immediately above the power tunnel. (Plate 12). Access
will be through an adit from the upper access road. The gate structure
will house two 6 feet by 12 feet slide gates in series. The dovm-
stream gate will be operating gate, designed to withstand pressure
head of 270 feet at normal stresses. The upstream gate will serve
as the bulkhead for servicing the operating gate. This gate will be
designed to withstand the full lake head pressure plus a 50 percent
over-pressure to withstand the blast at the time of the lake tap.
The bulkhead gate and the tunnel upstream of the bulkhead gate vlill
normally not be accessible. The power tunnel air vent will be a 30
inch diameter steel pipe extending along the access adit until it
rises vertically in a drilled hole, approximately 250 feet high, to
vent at the ground surface above the maximum pool elevation. There
will be a 20-ton monorail hoist capable of pulling the slide gate leaf
and stem. The machinery to operate the slide gates and a transformer
vault will be located in the chamber. A power tunnel access manhole
will be provided at the bottom of the chamber. The power tunnel will
be concrete lined for a minimum of 100 feet upstream and downstream of
the gate structure.
11.03 VENTILATION. A ventilation duct with blower will extend from
the gate chamber to the access adit portal to ventilate the chamber
and the adi t.
11.04 ELECTRICAL POWER. Overhead electricdl distribution can be
tapped from the existing Project 13.8 Kv camp feeder at the pOl'fer-
house-switch-yard location. The capacity of the existing 1/0 ACSR
line now serving the camp and Lon~, Lake is adequate for additional
Crater Lake gate and intake facilities.
11.05 A small unit substation will provide 480 volt power to the gate
control units. General lighting ~nd 120 V convenience outlets will be
provided ia the gate chamber. Telephones will be provided for communi-
cation between the gate structure and power house. Emergency power for
the gate structure will be provided by manual traasfer to a power out-
let and portable geaerator. This scheme is similar to Long Lake
emergency gate control. A suitable generator is available at Snettisham
as permanent operating equipment.
SECTION 12 -LAKE TAP
12.01 GENER4-. The lake tap will be directly into the power Lunritl with
the invert aL elevation 800, approxi:nately 220 feet below llormal. :1 ake level.
The tap will be made after the power tunnel is excavated and the c'perating
and bulkhead 9;ates ino;ta\led, \lith b,)th the bulkhead and cp8n.;~,n£ gates
closed. A rock trar is provided to =atch and permanently store the rock
L'rom the final plug. The power tunnel branches off from the side of the
rock trap above the Hoar level so tne rock from the blast wi ":.1 ne,t be
diverted into the power tunnel itself. The lake tap configuraj~ioL and rock
trap are shown on Plate 17.
12.02 ROCK TRAP. A large rock trap will be excavated with a~100r eleva-
tion 25 feet lower then the tap invert. It is designed with r1 dca.d end area
to permanently hold the rock plug to be removed in the tappir:g operation.
The power tunnel joins the rock trap, entering midway in the sid.::, wall with
a sill invert 8 feet above the rock trap floor. A second, smH1',~r rock
trap with a concrete sill in the floor is positioned in the ilOFer tunnel
about half way between the first rock trap and the gate structure (Pla~e 8).
·l2.03 TAPPING CPERA~ION 0 The rock trap and concrete si 11s u:i.ll te con-
:;tructed using the power tunnel for access. :he entire power .,unnel and
gate structure will be completed prior to the tapping operation. The rock
trap must be completely unwatered prior to the final tapping operation so
that the rock wi 11 move into the dead end trap. When everythi'IZ 's ready,
the final blast "Jill be made with both slide gates fully shut.. The entrapped
air in the power tunnel, upstream of the gates, will serve as a ·:.:ushion to
(~ncourage the rock to drop into the trap. The upstream slide gatt! wilL
be designed to withstand a blast pressure equal to 50 percent more than
its normal operating ?rcssure, with one section of the gate 'imd',el' tha:l
the rest. The dOvlllstream sLide gate serves as a backup for :::;1--l'il:;t:re 11'11
gate. It is expected that approximately 86 percent of the roc,:: w:_ll re-
main in the first rock trap, 11 percent will enter the Jecond".y:L trdp,
and 3 percent will be scat!~ered on the tunnel floor. 'rhese~L,,;., e.'> are
based on a model. ~:;tudy in Norway of a very similar lakt~ tap l[ ;:Lp; a heac.
of 85 meters (approximately 280 feet).
12.04 TRASHRj,CK INSTALLATION, Crater Lake i3 covered by ;e:' 'l't. August
t~ach year. To install a trash rack over the tunnel entrdllce, 'iill be
necessary to use iloating equipment and divers when there is no i.':: .. ~ pro1,lem.
Analyses of ir~flm1 to thE~ lake and rredicted ?ower consump~ 10.1 :!." ':he
Juneau area illdic'ltcs that Crater L.ske can be drawn down to ,-he m'~nimum
level prior to L June j,"1 ;lilY year by gerlerating the ma:d,mu!J. illilouni: 0 E power
with Unit 3. Hmvcve.r, lhe lake canr;ot be kep:: down into Augus': b(:caus('
of the limilLd power consumption anticipated until about the tenth year
of operation. Therefore, it will bE necessary, under th~ recounnended ,)lan,
to operate without an entrance trasrrack until power demanrl makes installa-
tion feasible. Sinee the anticipatEd debris problem is minor, 'l,~j'j,odic
reconnaissance of the lake surface end a minimum amount of debris remo1al
should prevent' any problem unti 1 tre:shr8,ck installation is posslb~e. At
I.:hat ti.me, ,1.0 t,.F' eIl(r:Jf!C'~ ',Jill be trimmed aI1d a trashrack ins:a-_led.
The rack will be bolted to the rock surface a~d encased in tremie concrete.
After installation of the tunnel entrance trashrack, the power tunnel will
be unwatered and inspected and the ~,ppet' half of the penstock trashrack
removed.
12.05 There is almost no floating cebris in Crater Lake. During the
initial lake drawdown, a close watd and coll'2ction of debris will be
maintained. In addition, there will be a full trashrack at the upstream
end of the penstock to prevent any cebris from reaching the turbine.
12.06 TWO STEP LAKE TAP. Plate 18 shoY7s the rock trap configuration for
a two step lake tap. This is essentially two rock traps with two upper
sections of power tunnel joining upstream of the gate structure. It is
intended to permit tapping the lake simultaneously at two levels. Such a
system is to be used if rock conditions encountered during excavation for
the one step lake tap make it unlikely that the one step tap will be
successful. In that event, the second rock trap and higher tap hole will
be excavated prior to any taP being attempted. The two taps will be
blasted simultaneously, resulting ir .. two lake entrances to the power
tunnel and requiring cwo trashracks.
12.07 DIVERSION TUNNEL LAKE TAP. The Long Lake tap was made into a sepa-
rate diversion tunnel. In that scheme, the gate was opened and the plug
rock was discharged into the stream. A small trap was provided at the
tunnel invert immediately downstream of the tap to catch and hold the rock
temporarily, permitting the rock to escape downstream as a gradual operation
so that the large mass would not plug the gate structure or tunnel. The
Crater Lake Diversion Tunnel tap would be similar, if this alternative is
selected.
12.08 If a diversion tunnel scheme, similar to the Long Lake scheme, is
to be selected, the main power tunnel would be excavated directly to the
lake wall without a tap. The separate diversion tunnel gate structure
would be provided with a permanently embedded gate frame and the operating
slide gate would be used temporarily and then moved to its permanent loca-
tion in the power tunnel gate structure with a permanent plug placed in
the diversion tunnel, (Plate 30).
12.09 The separate diversion tunnel scheme ia estimated to cost $2,623,000
more than the recomnlended plan, would require an access road and disposal
area, and would result in a much larger than normal, short time d~scharge
of muddy water down Crater Creek into Crater Cove. Therefore, this scheme
is not recommended.
SECTION 13 -Dfu~
13.01 GENERAL. The Project Plan and Reappraisal did not propose darning
the exit to Crater Lake and there have been no subsequent serious pro-
posals for a dam. However, preliminary investigation of two heights
of dams are presented.
13.02 INCREASED GENERATING CAPABILITIES. The principal result of a
dam will be to increase power output through increased head. Little
benefit is gained from increased storage capacity, because with proper
reservoir regulation, the entire inflow can be stored within the present
Crater Lake limits.
13.03 DAMSITE. Crater Creek drops rapidly immediately on exiting the
lake, limiting the available damsites to one location, the narrow ledge
at the lake. The narrowness of the ledge and foundation conditions
rule out any type of dam except a concrete gravity structure or a shorter
base post-tensioned structure.
13.04 STUDIES. Two heights of concrete gravity dams were investi-
gated with spillway crest elevation of 25 feet and 50 feet, re~pectively,
(Plates 35 and 36), higher than the natural lake exit crest elevation.
Both structures are ungated. The estimate investment costs are $3,204,000
for the 25 foot high structure and $6,491,000 for the 50 foot high
structure, resulting in annual costs of the investment for a 100-year
life of $106,000 and $213,000 respectively. Annual power benefits are
$52,000 and $111,000 respectively, use 9.91 mills per k.w.h. for average
annual energy. The cost figures do not include consideration of in-
creased requirements for the power conduit because of the higher pool
levels and resultant increased operating pressures.
13.05 CONCLUSIONS AND RECOMMENDATION. A dam at the outlet to Crater
Lake is not feasible at this time. The natural lake outlet presents
no danger of failure and consequent loss of storage during project life.
Therefore, the natural lake outlet will remain untouched.
13-1
SECTION lL;, -POWER PLANT
14.01 GENERAl:.. Powerhouse plans, basic data, cost estimat(;s and text
material concerning the power facilities in this design memorandum
were prepared by the Hydro-Electric Design Branch of the North }acific
Division. The existing powerhousE; is located underground dnd the
existing two units utilize water from Long Lake. The prop0sed :)lan,
contained herein for Unit 3, utilizes water from Crater Lake, a:1d final
recommendations for a firm basis of design wi 11 be contained iL a future
Preliminary Design Report No. 24, Powerhouse and Switchyard.
14.02 BASIC DATA (NEW CRATER LAKE UNIT unless noted).
Plant capacity, existing, 1.\.\01 (nameplate rating) 47,160
Plant capacity, ultimate, KW (nameplate rating) 74,160
Type of turbine Francis
Turbine rating, hp 37,000
Rating of generating unit, KW (nameplate) 21,000
Maximum pool elevation, Cnlter Lake, feet 1,022
Minimum pool elevation, Crater Lake, feet 82)
Maximum tailwater elevation, feet 11.4
Minimum tailwater elevation, feet (no flow) (-)5.5
Tailwater elevation, feet (300 cfs) (-)4.)
Elevation centerline turbine distributor, feet ( -):3 .J
Elevation bottom of draft tube, feet
Diameter of penstock, Crater Lake, feet 6.0
Diameter of penstock extension, feet 6.0
Spacing of main units, feet :::6.0
14.03 LAYOlfI AND SIZE. The powerhouse is an underground type, con-
sisting of five general features: Power chamber, valve roonl, access
tunnel, service tunnel, and tailrc.ce tunnel. The power chamber is
small, measuring overall 174.5 feE.t long by 38.5 feet wide, and 72.5
feet high. This cavity houses thE: erection area, the two exist'~ng Long
Lake generating units, the. electrical equipment, and space for:=he
installation of the proposed new 27,000 KW Crater Lake unit. The power
Chi1.8hcr i,-q!'l:'p,""ci with 6: 75-ton bridge crane for erection"1nd
maintenance. Power chamber eXCaV&1:l0n for installa .. ion of the :hird
unit is complete. The valve room (102.5 ft. long by 17.5 ft. wide and
25.5 ft. high) is located 35.5 feet upstrea:n of the power chamber.
This cavity houses the two penstock spherical valves for the existing
units, space for installation of the Crater Lake penstock valve (found-
ation excavation completed), and c. small "All frame type gantry crane
for installing and servicing the valves. Ac:cess to the valve room is
by a 12-foot wide by 14-foot high tunnel at one end and a 6-foot wide
by 7.5-foot high tunnel at the otter end. Excavation for the C'.:ater
Lake penstock into the valve room has been completed from the valve
room upstream for a distance of 150 feet. The access tunnel i3 220
feet long by 13 feet wide by 17 feet high A'.l equipment for:he third
unit must pass through this tunnel. Also, all additional excavation
below the surge tank access for tte penstock will have to be removed
through this tunnel (see para. 12.07). The tunnel connects the
electrical equipment area to the Ewitchyard. It is 430 feet long.
10 feet wide by 10 feet high. Personnel access to above ground can be
made through the diesel generator building, ap?rox'Lmately 240 feet from
the power chamber. The tailrace tunnel, approximatel y 290 feee: long,
begins in a trifurcation which combines the three draft tubes into a
single l3.5-foot wide by 39.5-foot high tunnel sec':ion. The overall
arrangement and location is shown on Plate 26. ~\ more detailed layout
is shown on Plate 27.
14.04 TURBINES 2 GENERATORS AND ELECTRICAL EQUIPMENT. The turb i.ne wi 11
be of the vertical shaft, Francis-type with steel spiral case and con-
crete elbow draft tube. Based on studies contained in Exhihit 2, the
unit will be designed to produce a guaranteed out~ut (dependable capacity)
of 37,000 HP (27,000 KW) at minimLm pool elevation. Best effic~ency
will be achieved at the average peol eleva1:ion (Figure 17). A spherical
valve will be provided upstream from the unit for emergency shatdown
and maintenance.
14.05 The vertical genel:ator THill be rated 30,000 )01A, 0.9 PF, 13.8 Kv,
514 RPM, at 60 0 C rise for contincous operation. A three-phase two-
winding power trans former will be located 1::1. the 138 Kv Sv1i tchyard near
the powerhouse. Provisions were made for adding 13.8 Kv switchgear and
control equipment for the third uc.it. Equiyment is existing in the
present 480 volt switchgear and pcwer control centers loads for the
third unit. Control features are deslgned for centralized control
from the powerhouse and remote costrol from Juneau.
14.06 TAILRACE. As previously dE-scribed, converging draft tube exten-
sions connected to a tailrac:e tunnel presen~ly exist with point of
convergence 70 feet downstream from the cen':erline of units. From that
point, the tunnel is 220 feet long to the tailrace channel. The last
75 feet of tunnel is outside the base of the mouni:ain and is formed by
a channel excavated in rock and covered with a reinforced concr8te
arch. The covering protects the channel from possible ice, mud, or
snow slides originating from the mountain side above. Also, the covering
forms a bridge for the access roadway leading to the power chambe ...
entrance.
14.07 CONSTRUCTION. Continued operation of the finished portion of
the valve room and the powerhouse requires that protection from dust
be provided during the Crater Lake construction. Such protection will
be provided by means of a temporaj~y dust barrier and temporary .::losure
tunnel constructed of wood framing covered with plywood and taped joints.
The dust barrier will be located ~_n the valve room and the closure
tunnel will be located between the valve room access tunnel and the
access tunnel as shown on Plate 2"/. Additionally, a differential
pressure between operating areas of the powerhouse and construction
areas will be provided by the heating and ventilating system. Waste
water from drilling and washing during penstock excavation will be
run through a closed system to the existing skeleton bay. The skeleton
bay will be used as a settling SUlap, and water will be pumped from the
sump to the existing draft tube bulkhead slot. The waste will be
cleaned out by other means. All existing concrete floors in work areas
during penstock excavation will be protected by wood decking.
14-3
SECTION 15 -TRANSMISSION LINE
15.01 GENERAL. The Snettisham Project transmission facilities
include the Snettisham switchyard. 40.5 miles of 3-phase overhead
conductors supported on aluminum towers, four 16,000 feet long sub-
marine cables, a cable terminal building at each end of the submarine
cables" and the Juneau substation and switchyard, Pla.te 1. These
facilities are to transmit power ~rom units 1 and 2 to Juneau. Little
additional work is required to increase the transmission facility
capabilities to transmit power from unit 3, the Crater Lake unit.
15.02 JUNEAU SUBSTATION .• The Juneau substation facilities, including
all switchyard equipment, are adequate to handle power from and control
of the Crater Lake facilities without revision, except for the addition
of a MW recorder and unit 3 status and alarm features to the status
switchboard in space provided.
15.03 SNETTISHAM SWITCHYARD. The existing switchyard consists of two
transformers, two transformer bays and one line bay with provisions
for a third transformer and bay and a future second line. The third
transformer and transformer bay will be added for the Crater Lake unit
in the switchyard space provided. Provision for the future second line
will be retained for use as the need arises.
15.04 COMMUNICATIONS. Remote control, telemetry, and superV1S1on is
provided through the existing powerline carrier communications system.
This system consists of two duplex channels between the Juneau sub-
station and Snettisham. No additional carrier equipment will be re-
quired.
15.05 MAINlENANCE. Manpower and equipment requirements for maintaining
the transmission facilities will not increase with the addition of Unit
3. The increased power to be transmitted, as the demand increases over
the years, is expected to reduce ~he icing problems on conductors and,
therefore, reduce maintenance requirements.
:i -i
SECTION 16 -ACCESS FACILITIES
16.01 GENElZAL. The recommended plan of development and each alternative
have their own requiremen'.::s for access. These requirements were briefly
outlined ill Sections 2 and 3 and are presented in more detail in this
S c'cti on,
16.02 RECOffrIENDED PLAN. The recon:mended plan requires access to two adits,
the surg;-tank access adit at approximately Elevation 740, and the gate
structure adit at approximately Elevation 820. Both adits will be reached
by a 5,600 foot long extension of the road to the Long Lake Surge Tank
Access Adit, Pldtes 19 and 20. The lake will be reached only by helicopter.
16.03 CRITERIA. The criteria for the roads was obtained from THS-822-2,
"General Provisions and Geometric Design for Roads, Streets, l..Jalks, and
Open Storage Areas."
16.04 ROAD TYJ:~. The roads fall under classification "F" of the criteria ----.--for single lane roads in mountainous terrain. The road sl.rface will be
compacted earth fill. A two lane road was rejected because of the horizontal
curvature LimiL'ltiollS of the criteria. The maximum degree of curve for a
two lane road subjected to snow and ice conditions is 16 degrees -30
minutes, which would not be possible in the steep terrain af the project
area, als0 the total width of rock cut would be 10 feet wide~ than that
required for a single lane road, greatly increasing the cost and the
environmental damage.
16.05 LANE WIDTH. A lane width of 12 feet rather than the 10 minimum
"~s chosen for the main access road because the average daily traffic (AnT)
and percentage of buses, trucks, and track laying vehicles (T) will probably
I'lJt fit into the traffic composition pattern shown in the:rLteria. The
minimum requirement of a 10-foot lane was chosen for the diversion tunnel
access rOdd because it will be abandoned after construction.
11).06 '§h~:)~LL.Q§E-ii. The ITlln~mUm width for shoulders on roacis vlithuut barrier
curbs is ii feet. The down slope shoulder is 6 feet because of tr,e ext)~a
i feet width requirement for guardrails. The shoulder sleres arE: 4R to IV
"r flatter so chey can be utilized by vehicle traffic.
16.07 GUAJWHAIL. The entire length of both roads wi 11 have a guardrai 1
OIL the dmmslope side. Pel'.sonal injury and property damage \voulc'. most
likely result ~f a vehicle were to run off the road at any pOint.
16.08 TURNOUTS. Six feet wide by fifty feet long turnou s will be pro-
vided a~1/4 mile intervals on each road or closer, if neccessary to be
intervisible.
16.09 g~\DE. The absolute maximum grade for the main access ro~d is
10 percent, The absolute maximum grade for the diversion tunnel road is
12 percenL. The grade for the roads as designed varies tlOm just less then
10 percent LO nearly flat.
16.10 HORIZONTAL CURVATURE. The absolute maximum horizontal curvature
for Class !IF" roads, where snow and ice are factors, is 58 degrees-OO
minutes. There will be as many as three curves on the main access road that
approach the maximum.
16.11 SIGHT DISTANCE. The rrnmmum stopping sight distance called for in
the criteria is 200 feet. This means that the middle ordinate (c2nterline
of lane to sight obstruction) would need to be about 47 feet. This is not
feasible for this project because 0= the steep rock slopes involved. The
amount of rock excavation required to provide the required middle ordinate
would be excessive. It is recommenned that the design be lowered by at
least 10 miles per hour on curves that do not meet sight distance criteria.
16.12 VERTICAL CURVATURE. No prob~ems are anticipated in meeting the
60 feet minimum length requirements for vertical curves.
16.13 CROSS SLOPE. The normal cross slope criteria for the road cross
section is from 1/4-inch per foot to 1/2-inch per foot. A cross slope of
1/2-inch per foot was chosen for the project roads to provide the best
possible drainage.
16.14 SPEEDS. The design speed is 20 m.p.h.; maximum speeds of 10 m.p.h.
should be posted on curves where the minimum stopping sight distance re-
quired by the criteria cannot be met.
16.15 CLEARING. The limits of clearing are 5 feet outward from the
extreme edges of the rock cut or toe of embankment.
16.16 ROCK CUT DISPOSAL. Rock frotn cut slopes will be disposed of four
ways:
a. For fill in the areas wh,:.re cut and fill sections are feasible;
b. For fill in areas where :urnouts are required;
c. For fill around culverts at stream crossings;
d. Rock that cannot be utilized for the above purposes will be
wasted in the designated disposal a~eas.
16.17 SEEDING. The fill slopes will be composed of rock fragments; there-
fore seeding of slopes will not be feasible.
16.18 SLOPE DRESSING. Rock cut sl.)pes and cleared portions of the natural
slope that are above the roadway will be cle&ned of all loose material
(organics, soil and rock fragments.)
16.19 DRAINAGE. Drainage faciliti~s will be provided for two purposes
along the roadway:
a, <:~tre:li". crossin~os wi 11 be 2 feet minimum diameter corrugated
b. Roadway surfaced drainage will be accomplished by providing
12-inch minimum diameter CMP at 400 feee intervals.
16.20 The culvert size and spacing will be optimized in the final design
by studying rainfall and snowmelt data. Provisions for dealing with icing
will also be studied.
16.21 ROAD MAINTENANCE. Maintenance of the main access road will be re-
quired during constructiono Periodj_c grading of the road surface will
be required because of use by heavy construction equipment. Snow removal is
a major problem if permanent access during construction is to be main-
tained. Past experiences indicated that snow removal is a "round-the.;.
clock" job during the winter. An e~~pense connected wi th snow removal is
replacement of guardrail destroyed by snow removal equipment. Maintenance
after construction will be performed only on the main access road. This
will consist of occasional grading and clearing of clogged culverts. Snow
machines should be used for gate structure access during the winter because
snow removal would not be economica:. Maintenance costs for the recommended
plan access road are estimated at $;'.0,000 to $15,000 annually.
SECTION 17 -BUILDINGS. GROUNDS, AND UTILITIES
17 .01 GENER..'-\L. The existing Govern.ment owned camp facilities, Ilate 25,
constructed in the first increment .Jf the Long Lake development and used
as Resident Engineer facilities during the lEter increments of the Long
Lake development., were scheduled to be converted to housing for operating
personnel, maintenance fadli ties a::ld visitors' faci li ties on cOlTpletion
of Long Lake development, as discussed in Design Memorandum No. 15,
"Building, Grounds, and Utilities." This work also included landscaping
the camp area. Most of this work was deleted from the present construction
contract so the facilities could be used "as is" during the Crater Lake
development.
17.02 DORMITORY. The existing dormitory has been converted to permanent
quarters for Alaska Power Administration operating personnel and their
families and is currently occupied ~y them. The Resident Engineer staff
for the Crater Lake development will be housed in facilities to be rrovided
by the main construction contractor under the terms of this contracl •
17.03 TR..4NSY.tISSION MAINTENANCE BUr ... DING. The existing Resident Engi.neer
Office will continue to be used as an office during the Crater Lake develop-
ment. Upon completion of the Crater-Lake phase, the building wi 11 be con-
verted to the Transmission Maintenance Building as described in Design
Memorandum No. 15.
17.04 TIDEWATER PICNIC SHELTER. A picnic shelter and visitors ar~a will
be provided at the close of the Crater Lake development. Various alter-
natives will be studied, including che conversion of the existing concrete
test lab.
17.05 CONTRACTOR FACILITIES. The contractor will supply his own bIi.ldings
including living quarters, dining facilities, etc. These will be e£ected
in the same area as previous camps and connected to existing utilities,
\Olhere possible.
17 .06 ~,~TER. Water for domestic and fire use is supplied by an exLshng
30 G.P.M. well and a 45,000 gallon ,3torage tank. Buried water liCles exL:>t
in the camp area.
17.07 SE\.JER. Buried sewer lines e:dst in the camp area and the cOltractor
will insure that all wastewater is eonveyed by the sewerlines to tn,= sCcNage
treatment facility. During construction of the Long Lake phase of:hi.3
project, the existing septic tank and leaching field were constantn'1in-
tenance problems and caused an odor nuisance. On at least two Sep&Clt::
occasions, the Alaska Department of Envirorunental Conservation re:].uired
immediate action to correct the nuir.ance and health problem cause} ;;y the
septic tank and leaching field. The existing septic tank does not meet
Federal or State Anti-pollution Standards. A separate sewage treatment
system which will comply with the nE:w Federal and State standards ""ill be
provided.
L?--l
17.08 SANITARY LA~1)FILL. A sanitary landfill, conforming to Alaska State
standards, will be provided under t~e Crater Lake construction contract.
17.09 ELECTRICAL POWER. Electrical power is from the existing hydroelectric
generators, driven by water from Long Lake. A backup diesel-electric
system is also available.
17.10 OTHER FACILITIES. The existing airfield, boat basin, dock and ware-
houses will remain as they presently are for use by the operating agency.
Landscaping will be accomplished as outlined in Design Memoranduffi No. 15
on completion of the Crater Lake development.
17-2
SECTION 18 -CONCRETE AGGREGATES
18.01 GENERAL.-The primary sourCE: of aggragate to be used in the pro-
duction of concrete for the Crater Lake phase of the Snettisham project
is contained in the Crater Cove aggregate so~rcc, Borrow Area One, and
in the Glacier Creek sand source, cesignated Borrow Area Two. The Gla-
cier Creek sand source was formerl) designated as Sand Source B und is
shown in the petrographic report, c.ated 10 December 1969, as Sand Source
D (See Plate 2). Both areas were Lsed as concrete aggregate sources
for construction under the main coctract for the Long Lake phase, It
is estimated 150,000 cubic yards of suitable aggregates are available
in Borrow Area One and over 50,000 cubic yards of material is available
in Borrow Area Two. The Crater Lake phase of the Snettisham Project
will require a maximum of 17,000 cubic yards of processed aggregates.
18.02 TESTS.-Testing of the Crater Cove aggragates was accompl~shed
by the North Pacific Division Laboratory and reported in March 1971.
The tests results for the Glacier Creek aggregates are contained in
Supplement No.1 to Design Memorandum No.7. Tests results indicate,
that with adequate,provisions and control of processing, concrete
aggregate of the quality required can be produced from the Crater Cove
source.
18.03 COSTS.-Cost data for the production of concrete contained in
Appendix A of Supplement No. 1 to Design Memorandum No. 7 is not JPpli-
cable to the Crater Lake phase of the Snettisham project since no dam
c.anstruction is contemplated and concrete quantities are considered
minor.
~':.:':i.!:.~.:...~J':-~E. 0<: Nov De.c
1913
}. 91 Ii 260 108 38,2
1915 313 10,~ 23.9
'1r.."'i£.. 1 r:r~ L~ _f~ ~ :~ -:-~,
.l.;f.l.V _~Vj "> .. '
1917 270 51 , ...
-',,;.,. .t
laiC! '" ,,'A~~ ;51 2"" .\., 3~,
1919 202 133 65.(
InO 209 67 l:.5
1921 14() 91. f ~ . "i L!.';p • l
1923 202 158 40. 'I'
1924
1927
192f' 13: 48 :E:
'-.)
1929 194-~ ~ ..> 13' .-::
1930 46.~:, 222 60 '\ -
l.~~ ~'l J"! .; 2% le!~f
1" -," ~ ';L. " "' ~~ f; .... /< ~.fl. J L. :
1933 316 42.2 26.5
'-q
Gl
C
:JJ
iTl
en
FIGURE 6
~....Ml DIS(]"~~GE DAT},
CRATER CREL.:( ~~EAR Je~t:AI;
D'raLlnge Are.a 11, 4 Squore ~.:5.1e,.
Gage Elevation 1.010 Feet
J i~;1 Feb MaY" .~.E£ !:~-2_
47.0 48.3 57.3 203
~:(j Q 4'l 36.7 S2.f 144
~J t') 1 17. 2 44.6 74 235
1 , Q 19 44 0(';
.LU ""
3',~ . i:. ~4,,5 22.5 23,8 1.42
:';'" '2 16.8 12. ... 20. -l?9 ! t
,jF3~4 14. £. 12 47 118 ' ,".'. eve 35 16 20 53.4
}1': 'j ~~ (.l .. , 3(\. ) f,.,C .v. -, 42. ? i9J
I~ li t9 49.4 29, -; 91 ,9 .,
-.} j , J' l 1ft. 7 34,'; 11)4
";l; ~ 1.02 ;~:; . '1 43. " 1 •
" J ,J '<'J...l
"1,. ') 20, 0 15.0 V.,9 10j
]lm JuI ~ul; ~-~£ The <': ~~l-~_ ----------
531 830 858 491
277 517 409 2. ')6 18;;;
41~ 1..,91 469 389 2IS
"l.7f1 "l."1(. L~6f.; ~ll U JIY
j, '10 1 "l?-' ",oR'" J>,.I"-
305 441 539 361 190
347 482 SQ' J>" I{ll 219
?~7 ..... ..;.,., 417 5 \ . .... 1. L':iO 18'7
171 406 532 262 16:1
lOS 399 360
291 452 483 502
400 584 586 581
350 377 3.57 :'~?
3,'H 528 377 3', '~ 18?
38i 419 404 34., IS'}
3DF'· 420 t.8" 1"" .,J_ v 208
402 417 '-' 4/!.4 361 228
284 362 366 42'1 173
Year
1913
1914
1915
1916
1917
1918
1919
1920
1921
1923
1924
1927
1928
1929
1930
1911
1932
'q 1933
-
Cl
C
.:0 rn
---J
FIGURE 7
PEAK A.\~lJAL DISCHARGE DATA
CRATER CREEK ~r:AR JL:;EAC
Drainage Area 11.4 Square Xiles
Gage Elevation 1,010 Feet
Yearly discharge, in cubic feet per second
_. ________ Water .. "!_t!.aI. _r.:.~~~~g 5~£~_~~b~!"..1Q. __________ .. ____ . __ _
Momentary Maximum Minimum Runoff in
Di.sc~E&"<:' Date _~~L-_ Mean As.!:~Feet_
6 182 132.000
1~680 1.3 Aile Ie; 10 219 159,000
5 178 129.000
1,270 19 Aug 17 12 190 138,000
2,300 26 Sep 18 10 219 156,000
5 187 135.000
2.100 6 Aug 20 161 117.000
3,100 9 Sep 27
L,890 2~ .lui 28 8 187 136,000
1.380 13 Sep 29 12 185 134,000
1,920 12 Aug 30 208 151,000
228 165,000
1,780 11 Or-~ ... 31 173 126.000
Calendar Year
Runoff in
Mean Acre-··Feet
185 134,000
204 148,000
185 134.000
207 148 t OOO
206 148,uOU
180 130,000
156 113,000
202 147,000
215 155,000
198 143.000
212 154,OOCl
169 122,000
SECTION 19 -PUBLIC USE PLAN
19.01 GENERAL.-The project lands are located almost entirely within
the boundaries of the Tongass National Forest. The Forest Service and
Corps of Engineers developed a "Menorandum of Understanding" relative
to management of the lands encompa~,sed by the proj ect in 1964 and
amended it in 1967. The rorest Sel'vice, upon completion of the ?ro-
ject, will assume responsibilicy for the management of project lands
and for the development and management of all recreation facilities
that were not directly related to structures pertinent to producing
electrical power. The Corps of Engineers and Alaska Power Adminis-
tration will be responsible for developing recreational facilities
related to project features.
19.02 RECREATION OPPORTUNITIES.-The Crater Lake Project will not
provide any outstanding recreational opportunities directly connected
with project features. There will be neither a large dam structure
nor vast reservoir with accompanying water-oriented recreation activ-
ities. However, the Snettisham Project, as a whole, will offer several
recreational attractions.
19.03 Crater Lake, sitting in a narrow, mountainous drainage basin
with very steep valley walls, is not suitable for extensive public
use development. The lake is not =_nhabi ted by fish; consequently
there is no sport fishing activity. Due to the Lake's cold summer
surface temperature, lengthy periods of ice cover extending into the
summer months, and poor accessibility, water skiing and swimming are
undesirable.
19.04 RECREATION DEVELOPMENT -COI~PS OF ENGINEERS.-The Corps of
Engineers and Alaska Power Administration have envisioned providing
a picnic/visitor shelter in the canp area. This shelter will be a
cooperative effort between the Forest Service, Corps of Engineers,
and Alaska Power Administration.
19.05 RECREATION DEVELOPMENT.-In May 1973, the Forest Service ?re-
pared a preliminary plan for recreation developments for the Snettisham
Project and contiguous area. This plan will form the basis for detailed
planning relative to a formal publ~c use management plan. Recreation
developments or facilities that tht! Forest Service has indicated they
could incorporate into their public use management plan are: small-
boat harbor; airstrip; trail systeIJ.; campground; picnic/visitor shelter;
restrooms, and possibly a boat and aircraft fueling station. There
are no Forest Service spol.1scred recreation facilities planned specifi-
cally for the Crater Lake area.
SE.CTION 20 -DESIGN A~'D CONSTRUCTION SCHEDULE
20.01 GENERAL. A condensed scbedu'~e for design ,:md constl'uction of
Crater Lake phase of the Snettisham project has been developed, using the
critical path method, and is shown \m Figure 19. The following discussion
and Figure 18 are made with the assumption tbat there will be no delays
in construction appropriations which 'would rE;sult in corresponding delays
in the schedule.
20.02 DESIGN SCHEDULE. The demand for power in the Juneau area is increasing
steadily. Once the Snettisham Long Lake phase goes on the line, Snettisham
will become the sale source of powe~ for the area. Projected power re-
quirements indicate a need for the Crater Lake unit in the Fall of 1977.
The schedule has been developed usL1.g this as a power on line date. It
is recognized that the time available is limited and that this will be a
difficult schedule to maintain.
20.03 CONSTRUCTION CONTRACTS. Present planning is based on construction
of the project under one main contract, which will be primarily an ex-
cavation contract, including excavation of the power tunnel, surge tank,
gate shaft, access adits and lake tap. It will also include the gate
structure and gates, completion of the power house for Unit No.3, access
road to the adit tunnels, final grading and landscaping, and renovation
of permanent buildings. The main contract is scheduled for award in August
1975 and for completion in November 1978.
20.04 SUPPLY CONTRACTS Q Several procurement contracts will be required
for the power plant and miscellaneoJs equipment with schedules depending
upon manufacturing lead time and on installation schedules. The earliest
award date for the turbine will be ·::ontingent upon appropriation of con-
struction funds. This contract is tentatively scheduled for award in
September 1974.
20.05 FUNDING REQUIREMENTS. In ac::ordance vii th the foregoing discussions,
fund requirements by fiscal years f~r the Crater Lake phase of the Snettisham
project are as shown in the following tabulation:
Fiscal Year
1973
1974
1975
1976
1977
1978
TOTAL
Present PB-2A
R3quirement
$ 288,000
456,000
1,400,000
5,600,000
12.600.000
1,859,800
$22,203,800
DM 23
Requirement
$' 288,000
456,000
1,400,000
9,100,000
9,700,000
4,540,000
$25,484,000
SECTION 21 -OPEiMTIONS AND MAINTENANCE
21.01 GENERAL. The Snettisham Project will be operated and maintained
by the Alaska Power Administration, Department of the Interior. Project
administration will be located in J'Jneau and routine operation wi 11 be
controlled at the Juneau Substation. Three operator/maintenance men are
presently stationed at the project 3ite at SLettisham to operate and
maintain the existing facilities. jdditional personn~l will be temporarily
assigned to the project, as necessa':y, for major maintenance. The per-
manent operating equipment, discuss.~d i<1 Design Memorandum No. 14, "Per-
manent Operating Equipmentll, wi 11 b.~ adequate for maintaining the additional
facilities presented in this design memorandum. No additional permanent
staffing requirements are foreseenw:~th the acdition of the Crater Lake
phase. The temporary staffing requirements will be extended over a longer
period of time at the project site.
21.02 TRANSMISSION LINE. Transmission line maintenance requirements may
be reduced with the addition of the Crater Lake phase. The additional
power transmission is expected to heat the conductors, reducing ice and
snow accumulations and related problems.
21-1
SECTION 22 -COORDIi~ATION WITH OTHER AGENCIL'
22.01 CE!::iER.A~. The hyd·coelectric Dower potentials of CratE1 and Long
Lakes weye initiaUy investigated b} a private mining corporc,Uon (Speel
River Project, Inc.) in 1913 with subsequent private corpolation studies
ffiade in 1920, 1921, 1924, and 1927. Throughout the next 30 years, Federal
agencies (Geoiogical Survey, Forest Service, Corps of Engineers, Federal
tower Comr:lis~;ion, and Fish and WildLife Service) prepared various reports
on the Crater and Long Lakes power }roject.
22.02 Durini:': the preparation of the 22 CorpE of Engineers' Design Memo-
randa, primarily covering the Long ~ake phase of the project, coordination
was maintained and reports received from various Federal and ~tate agencies.
:C2.03 FOREST SERVICE. The project is located almost elltirely \'Jithin the
boundaries of the TongassNational Forest. In 1967, the Corps of Engineers
and Forest Service developed an agreement entitled "Memorandum of Agree-
l;,ent betweel: the Secretaries of Arm} and Agriculture Relative to l1anage-
tnent of Land and Water Development Projects of the Corps of Er'gilleers
located wi thi.n a Nat.ional Forest." The Memorandum of Agreement involved
the granting of permission by the Forest Service for the Corps of Engineers
to occupy National Forest lands necessary for the planning a~ti construction
(·f the Snettisham Project. It also stated that, upon coruplel~un of the
project, the Forest Service would a;3sume responsibility fo:: the management
cf project lands and for development and maintenance of land find water-
(Iriented recreation resources. The agreement provided for t:lt~ preparation
of detailed plans and recommendations for land uses, timber: hc.rvesting,
land clearing, fire control, public relations, and recreatioaul facilities.
22.04 Previously submitted Design :1emoranda have been l-eviewcd by the
Forest Service, dnd their comments :hereon h2ve been inc'n~pOL1\ed into
the project design. Criteria for Lmd clearing, spoi] dispos " and ·;:oad
constructic.[l will continue Lo be cOdrdinB ted wi th tht l'uu:::;. .. '",k. L:e.
:)2.05 FISH AND WILDLIFE INTERESTS. During ~)re[JaraLi.(r: Oi;,'('8U of
RecL;,a,,~i~-r·l~ql initial fea~-iblity rec1 ort, the U.S. Fish ",ld ',:J id.12 Service
submi::led their report on the proje~L in accordance with tHe :;':sh and
\iildUfe c:oordination Act. The Sta·~(: Department of Fish ;nr' ;~m€ con-
curred with the U.S. F:ish and Wildlife Services' evaL1l3t](1~;, j:",th agencies
have been l'equested to COTIunent on all (esign memoranda.
2.2.0b fEDERAL POWER COHHTSSION. Th2 San Francisco offie., ')1 i.[l(!. Federal
Power CommL,sion has been ke~~-t· ·info:::med of tf.,e generdl ,:'C8rLS cf the
Snett:isham Pr',Jject. The Federal PO',oJer Commi::osion tunllshc.l ,,,),\/er values
for use in economic analyses.
22.07 ALAS}~\ POWER ADMINISTRATION. The Snettisham Project authorization
provided for construction by the Co~ps of Engineers and for operation
and maintenance by the Department of Interior. The Bureau of Reclamation
was the original operat~ng agency by intent, unLil DeparLmant of the
Inter :;1 ()l"1cr N\). 290f) e:,tabU shed the Alaska 1'0"'181.' AdllliLislration as the
responsible agency to operate the project and market the power g€.nerated.
Therefore, close coordination has been required and maintained between
APA and the Corps of Engineers. Nurr.erous conferences and exchang€.s of data
and information have taken place during the course of studies leacing to
the design and construction of the Long Lake phase as well as design
studies for preparation of the CratEr Lake De:3ign Memoranda. All pre-
viously submitted Design Hemoranda have been reviewed by the Alaska Power
Administration, with app licab Ie comrr.ents inco:: porated.
22.08 OTHER AGE~CIES. Various other Federal} State, and local agencies
have been contacted infonnally duriEg the cou:cse of planning stud:'..es.
Bonneville Power Administration shared results of their extensive experience
in construction and operation of transmission lines, including sait water
exposure and submarine cable installations. The U,S. Coast and Geodetic
Survey furnished information on survey monuments and bench marks. The
U.S, Geological Survey cooperated in establis}lment of a tide gage, and in
the gathering of hydrologic data. The Soil Conservation Service assisted
in the establishment of snow courses and the D,S. Weather Bureau :i_Ilstalled
a climatological station near the mouth of the Speel River. The U. S.
Bureau of Land Management, the State Division of Lands 4nd the city of
Juneau cooperated during the project investigations.
22.09 PUBLIC COORDINATION. Generally, there was very little public co-
ordination effort accomplished during the construction of the Long Lake
phase. It was not until 29 May 1970 that a public meeting was held in
Juneau, Alaska, to discuss project features, both under construction and
proposed. The meeting was conducted pursuant to the provisions of the
National Environmental Policy Act of 1969, Public Law 91-190, and because
of an expressed interest by the pub:ic in the project. The meeti~g mainly
involved discussion of the transmisf;ion power line routing from the
Snettisharn Project area to the Juneau Substation, a distance of about
45 miles.
22.10 Following the 29 May 1970 public meeting, an Environmental Impact
Statement was prepared on the Long Lake phase by the Corps of Engineers
and submitted to the Council on Env:·.ronmental Quality on 22 Janua:cy 1971.
The statement was never circulated ::or review to Federal, State or local
agencies or to citizen organizations.
22.11 FUTURE COORDINATION. A draft and final Environmental Impa::::t State-
ment will be circulated to solicit :_nformation from Federal, Stat<~ and
local organizations and to publicize the intent of the Corps of E::.lgineers
to construct the Crater Lake phase of the project.
SECTION 23 .. COST COMPARISON
23. 01 CI~NERAL DESIGN t-'lEHQ., CG?LEST:.HAT~. Design Hemorandum La .. 7, ~;eneral
Design Memorandum, presented the fo",lowing estimated costs for Lh., CraLer
Lake Phase at the Snettisham Project. (in tho~sands of dollars):
Cost
Acct
No.
04.
.4
UJ.
.1
.2
,3
.8
30,
31.
Feature
Dams
Power Intake WOl'ks
Power Plant
Powerhouse
Turbines and Generators
Accessory & Misc. Equip.,
Tailrace
Tr.ansmission Plc;nt
EngineeLing dW.1 IJesign
Supervieion aud Administration
TOTAL COST, SECOND STAGE
DEVELOPMENT
PresCl.t
Es ti md ti.
Oct 1965:,ase
8,412
(8,412)
2,388
(95)
(1,j55)
U49)
('.89,
1 > 20li
1) ooe
13 ,IOU
23.02 COMPARISON OF CURRENT APPROVED ESTIHATE \-lITH PRESENT ESTlMJ\TE. The
latest approved Detailed Project Scbedule (PB2A) was dated 1 3el'icmiJer 1973.
This PL;-2A estimate was based on the detailed cost estimare p:e,,~'nted in
the General Design Memorandum, No.7, increased to 196 percen! of the
October 1965 base to reflect construction cost increases in 0te 'nt~rvening
8 years. Subsequent to the issuancE of the General Desigll Me,HOlandum,
severa 1 aeci[,;ions were made which rcduced the estimate:
a. The CHange to an undergrollnd powerhOllSf' reduced the 'ien',L.li ,·1 C·.·S t-
of the pc>nstock;
b. lou excuvat:ion for the undergroLlnc: powerhouse in the Long ',<'k.,; PLd,.;e
included \vork for the Crater Lake Phase, thereby reducing the c· '.:._ l,ited
cost for completion of the pow(;rhouse;
c. The second transforwe:c at. the Juneau Substation, require" t'l1~ -:I:t.~
Crater Lake Phase, was installed in the original construct:Lon. ·_I·_,U<"' _.ng
the estimated cost for completion of the Transmission Plant.
23.03 The present f;stimate aLld latest appr-oved l:'b-2A es:::imaL_~l.ll __ heu-
sands of dollars) are:
Cost
Acct
No.
04.
.4
07.
.1
.2
. 3
.8
08.
19.
30.
31.
Feature
Darn
Power Intake Horks
Power Plar:t
Powerhouse
Tcirbines and Generato~s
Accessory Electrical Equip .
Transmission Plant
Roads
Buildings, Grounds, Ut~lities
Engineering and Design
Supervision and Administration
TarAL COST, SECOND STAGE
DEVELOPMEW.i
Present
Estimate
Sept. 1973 Base
17,283
(17,283)
3,144
(287)
(2,526)
(318)
(12)
639
595
1,733
2,090
25,484
Latest Approved
Es ti;nate
July 1973 Base
13,819.4
(13,819.4)
3)896.9
(180)
(2,580)
(450)
(686.9)
1,344.3
60
l,583
1,500.2
22,203.8
23.04 The estimated cost of the po"er intake works exceeds the latest
approved estimate by $3,463,600. However, no provision was included in
either the General Design Memo or the latest approved estimate for the lake
tap and diversion facilities originally envisioned and currently estimated
to cost $2,346,000. In addition, the current estimated cost of the power
intake facilities on which both the General Design Memo and latest approved
estimate are based, is reported in this design memo as the Intake Structure
Alternative. This estimated cost is $15,742,000, an increase of $1,922,600
over that which is reported in the PB-2A. This increased cost is the result
of more detailed study than that wh~.ch resulted in the General Design
Memo estimate, with the added exper::'ence of the Long Lake develop:nent in
the intervening years. Therefore, che true cos t comparison for tL1e power
intake works is between the $17,28:>,000 recorrunended [llan estimat2 and the
$L8,088,000 cost of the power intakl~ works fer the Intake Structure Alter-
native plus the diversion facilitie8.
23.05 The estirna.:ed cost of the pouerhouse construction has increased
$107,000 over the latest approved estimate. This increase includ2s the
costs of the penstock extension, the special powerhouse features to permit
penstock construction while maintaining an operatin:s underground :Jower-
house, and the adjustments in unit rrices as a result of experience in the
Long Lake development. The estimat(!d costs for powerplant accessory
electrical ~quipment and for transm:.ssion plant have decreased $132,000
and $674,900 respectively because some of the accessory electrical equip-
ment and most of the transmission p:ant have been installed in th3 Long
Lake development.
23.06 Estimated costs for roads have decreased $705,300 because :here is
no longer a need to extend the road& to an intake structJre or di~ersion
outlet structlire.
23.07 Estimated costs for the buildings, grounds and utilities have in-
creased $535,000 because the converf:ion of the buildings and some land-
scaping has been deleted from the Long Lake development and scheduled to be
a part of the Crater Lake development. These facilities are needed in
their present condition for Crater Lake construction facilities. The
increased cost also includes funds ~or construction of a sewage lagoon to
meet State water quality standards, which have changed since the General
Design Memo was issued.
23.08 Estimated costs for Engineer:_ng and Design are computed at 8% of
construction costs as in the approved estimate. Supervision and Administra-
tion estimated costs have been increased because experience has shown that
the difficult construction conditions at Snettisham make supervision more
expensive than previously estimated.
23-3
SECTION 24 -POwER STUDIES 2 BENEFITS AND ECONOMICS
24.01 n,lTRODLJCTION. The power studies were prepared by the Wate~ Control
Branch, North Pacific Division, and economic analyses were prepared by the
Alaska District. Electric power load projections, indicating the Crater
Lake generating unit will be needed by the Fall of 1977, were "Lade by the
Alaska Power Administration.
24.02 PO\o,TER OUTPUT COMPUTATIONS. ~':he electric power potential of both
Crater Lake and Long Lake has been investigated by private interests, the
Bureau of Reclamation, the U.S. Geological Survey, and the Corps of Engineers.
The most recent of those investigat~ons was reported in Design Meillorandum
No. 2 -Hydropower Capacity, issued October 1964 and Design Me~orandum
No.3 -Selection of Plan of Development, Revised May 1965. Additional
power output computations for Crater Lake have been made for this Design
Memorandum, to determine optimum size of the installation and to evaluate
the feasibility of a low head dam in conjunction with the Crater Lake
development. The basic power outpu: computations have been based on average
monthly streamflo\Js as regulated by Crater Lake storage operations. There
are no requiremt!nts for use of Crater Lake storage other than power produc-
tion; hence the operation of Crater Lake storage is wholly power oriented.
By using historical runoff records and correlations, a total of688 months
of streamflow records were made available for the power regulation studies
discussed herein.
24.03 EXISTING ELECTRIC POWER RESOURCES. The Juneau-Douglas area is pres-
ently served by the Alaska Electric Light and Power Company (AEL&P) and
the Glacier Highway Electric Association, with power supplied from the plants
of AEL&P. The Glacier Highway Electric Association is presently a who1e-
~.,a1e customer of AEL&P, but will be~ome a preference customer of Alaska
Power Administration (APA) upon com:J1etion of the Snettisham Projer:t.
Three small hydroelectric plants in the area, with a combined cal:acity of
7,200 K,,,, were constructed in 1915 to supply power for gold Elining op-
erations and the mining camps. All mining activities are now c1csed and
these 3 plants are now operated by AEL&P. The AEL&P owns l~nd r'-,'crates
seven diesel-driven generators, witl a combh,ed capacity or 13,550 kilo-
\latts, and four run-ot-river hydroelectric units totaling 1,600 kilowatts.
These run-of-river units are not su)ported by storage, hence their capacity
1-s not dependable. The combi-ned existing dependable capacity therefore
totals 20,650 kilowatts, as shown i:1 the fo1l.owing tabulation:
Plant
Salmon Creek if1
Salmon Creek #2
Annex Creek
Gold Creek
Gold Creek
Lemon Creek
Unit '~:~
Hydro
Hydro
Hydro
Hydro
Diesel
Diesel
Number of Units
.. L
-'
r:
-'
r, .',
'.COTAL
Present Firm Capacity (KW)
1,400
2,800
3,000
No f. carage
8,050
5,500
24.04 ELECTRIC POWER. REQUIREMENTS. As a part of their responsibilities,
APA ill coordination with the FederaL Power Conunission conducts electrLc
power 101ld projections [or the various boroubhs and the state as a whole.
A tabulation prepared by APA in January 1973 showing the re-
corded electric power use in the JUleau area fo·r calendar years 1950 through
1972 and their forecasts of annual demands for calendar years 1973 through
1990, inclusive, is at the end of this sectio~
24.05 The obvious increase in growth projections for 1974 are ccnsidered
logical in light of planned and anticipated developments. The addition of
a new capitol building, an 8 story~partment building and an 8 story Hilton
Hotel are all to be completed befora 1977. These extra loads are estimated
to have a peak demand of 4,300 Kw. and an energy requirement of 18.5 million
Kwh. per year in addition to the normal load growth of the Juneau area
(see Exhibit 5). The possibility of fuel shortages and price increases,
and the possibility of limited fuel even with price increases brings to
light the question of converting to electric heat, not yet considered in
present growth projections (See Figures 12 and 13).
24. 06 TURBINE Ar,'1) GENERATOR EFFICENCIES. The efficiency of a turbine
varies both with load and with the percentage of the design head at which
it is being operated. Generator efficiency varies with the percentage of
the full load at which it is operating. Considering the wide range of
gate openings at which the Crater Lake turbine will be operating, a factor
of 0.073 kw per cfs x Head at full ?ower pool was assumed for the current
studies. With the reservoir drawn down to minimum pool, a factor of 0.0675
was used.
24.07 POWER REGULATION STUDIES. T.le first step in a power outpt:t study is
to determine the critical power period. Examination of the streamflow
records show several potentially critical periods. A differential mass
diagram was developed so that each ::Jeriod and the most critical period be-
came identifiable. It then became ::l matter of checking out the most severe
periods by regulation of the storag~ and in this manner the 43-month stream-
flow period, November 1919 through\fay 1923, incl. proved to be the most
critical. The [,ower regulations co·"ering the critical period were first
made on the basis of providing a cOCltinuous uniform output throughout the
period. After the most critical period was definitely established, the
storage was then regulated to provide a shaped output over the critical
period that would be similar to the Juneau area load shape. The load shape
used was given in Tab le 2 -Design.1emorandun No. 2 -Hydro-power Capacity -
October 1964. It was found there was very l~ttle difference in project
average output whether it vias operated on a shaped or uniform output. There-
fore it was considered unnecessary to regulate the storage to provide a
shaped output over the entire period of record.
24. 08 NORc"'1AL FU~L AND NgIHU.!"l LAKE ELEVATIONS. The approximate elevation
of the natural outlet of Crater Lake is elevation 1022. Therefore, for the
power regulation studies, the maximJm power pool if no dam is cOEstructed
at Crater Lake outlet ;·L3S been sele::ted at elevation 1022. The rr.inimum
power pool of elE'd1"ion 8:,.0 has bee:l selectecl to provide 20 feet: of depth
above the invert: elev'~Lion 'Jf the LIke tap. The lake lap elevat:'on has b(:~ei1
determined primarily for ro<:k qualL:y and lack of overburden. Iii addition,
examination of the area-capacity curves, Figure la, shm-ls there it; very
little storage to be gained by additional drawdown and powcrwi.se the re-
sultant head loss would probably offset the storage gain. The pr~jecl
was regulated such that lhe total storage available betwpen elnratiolls
1022 and ~20 was fully utilized during the critical period (lj.3 months,
Nov 1919 -May 1923, inclusive). Prime power is based on the average energy
produced during this period. Figure 18 is a reproduction of the ~ritical
period regulation study. In addition, the flows of the full 688-month
period ofrtcord were regulated and the average annual ener[;y com Ju;"ed,
24.09 NOR ... l'1AL FULL POOL WITH A LOW-HEAD DAM. In order to JeteJ~mL1(; the
feasibilit.y of providing a lm,,-head dam at the lake outlet, aduiti.on;l.l
power output computations were made, These studies covered the c:.::it..lcal
period only (43 months, Nov 1919 -Hay 1923, incl.). Although the studies
were limited to the critical period, they provide an excellent Tl.'3SUle of
rhe incremental firm pO\lcr that could be developed. These stud l.e:; assultl"d
a t.wenty-five foot and a fifty foot increase in normal filll lak~ el.vation.
Following is a comparisun of the project characteristics:
No Dam 25-Ft. Inc): SO-Ft, Iocr. -----.... -~
Full lake elevation, Ft. 1,022 1, Oi~ 7 1,07:-'
l"ull lake storage, AF 121,000 1.35,000 'L52,000
Min, lake elevation, Ft.. 820 82U 820
Hin. lake elevat.ion, AF 37,000 37,000 3"i,OOO
Vsab le storage, AF 84,000 98,000 115,000
24.10 INSTALLED CAPACITY. PrelimiLary studies for the Crater Luke aevelo[-
ment, which \vcre based on a project without a dam, indicrl:...ed ,1 :~7 ;,00 lev
nameplate unit to be the largest that could be accommodated. Hi1'n VlC
higher heads associated \lith a dam, a some,,,hat larger U1Lt mi;;i1t ':"ds,)it.,
however, one of the controlling factors will :)e the capacity ot t,·! ex.i' l:1li')
rrane. Because of these unknown elements, a '21 ,000 ku namep1:it",:'I~I' 1.va·::
used in (Hell of the three fJower regulation studies des~r:i.bec1 al"h"'~' Titl:'
turbine \-]ould be designed to rroduce the gene:=ator nat'1epla<:c rae; ell'; "l'
minimum head.
24.11 STUQ.LRESULTS. The studies produced the following J'esuli.f .
No Dam ~: 5 -}'t. I; :[;1
Average Annual Firm Energy, K • .;rh ----103,000,000
___ .... £ __ 0,_-
1(l8,60C,nrc
:Fi.rm energy is defined as electric eaergy which is intenoe(\ to have aSEured
l 1 t 11 a r ' d port';OJl 0'., !,'1i.~. ·,i.oc:d availability to t1e customer ;0 mee a _ or any .~ ee .. ~ ."
requirements.
2l~. 12 ANNUAL POW-£R BENEFITS. The b2.ne fi. t val.ue of hyclroe ~ec~:;::L( : ()weJ~:.~o
measured b~;-the CCJst of rro';iding the equivalent. power :t::rOPi th(: ll'::O81. likely
1 t e· ... 1"' '; r'[ \', 'lIr C' i' 1 n t b e JUli"";U etC ea the :1:. tern a t i ve 1. s cons i(1 c.r eel b:, chi'-
Federal Power Commission to be a pr~vately financed, oil-fired, steam-
electric plant located in the outsk~rts of Juneau so that no transmission
is required. The power values are divided into two components, the flrm
capacity value and the energy value. No distinction is made between the
value of firm energy and secondary energy. Taxes and insurance costs, as
applicable, are included in the power value. The power values for
Snettisham Project, furnished by the Federal Power Commission by letter
dated December 17, 1971 (Exhibit 4) are:
Dependable Capacity:
Average Annual Energy:
$78.51 per Kw-yr.
9.91 mills per Kwh
Power benefit computations for a project without a dam assuming 6 percent
transmission losses on both the capacity and energy components are as
follows:
Dependable Capacity:
Ave. Annual Energy:
27,000 Kw x $78.51 x 0.94 = $1,992,600
103,000 Kwh x $0.00991 x 0.94= 959,000
TOTAL $2,952,000
The average annual value from 96 years of production at Crater Lake is
calculated by applying a uniform series factor for 96 years at 3-1/8%
interest to the annual benefits as fO.hown above. This present wori.:h value is
than adjusted by a capital recovery factor for 100 years at 3-1/8%, giving
annual benefits of:
$2,952,000 x 26.817 x 0.03276 = $2,593,000.00
24.13 LIMITING ALTERNATIVE COSTS. Comparably financed alternative costs,
hereafter referred to as "limiting alternative costs" are also measured by
the cost of providing the equivalent power from the most likely a._ternative
source, except that these are based on financing comparable to the Federal
hydroelectric project under consideration; 1.,=., the same interest rate and
without taxes and insurance. These limiting alternative costs are used in
project scoping analyses; e.g., project economic feasiblity, sizing of
tunnels and penstocks, number and size of generating units, height of dams,
etc. This is in compliance with the standards of Senate Document 97, which
requires that Federal hydroelectric projects meet a test that there is no
more economical means, eva;_uated on a comparable basis, of providing the
project services. The limiting alternative costs for Snettisham were
furnished by the FederaL Powe~ Commission in the same letter furnishing
the power values. Based on Federal financing at 3-1/8 percent interest
(the interest rate applicable to boti the Long Lake and Crater Lake develop-
ments), the annual limiting alternative costs are:
Dependable capacity: $39.99 per kilmvatt-year
Average annual eneq;;y: 9.91 mills per kilowatt-hour.
24.14 LIHITLD BEI\EFIT S. Based on the limi ting a 1 terna ti ve cos ts quoted
above, the limited power benefits have been (~etermined for (1) Crater Lake
Development without a dam, (2) Crater Lake Development with a 2S-ft. dam,
.and (3) Crater Lake Development with a SO-ft. dam.
a. Crater L:lke Development Witho..lt a Dam: Limited benefit COlf.putations
for Crater Lake development without a dam, assuming 6 percent transmission
losses on both capacity and energy components, are as follows:
Dependable capacity:
Ave. annual energy:
27,000 Kw x $39.99 x 0.94
103,000 Kwh x $0.00991 x 0.94
Rounded
$1,014,900
$ 9S9,SOO
$1,974,400
$1,974,000
b. Crater Lake Based on Firm Ene~gy: As discussed earlier, power reg-
ulation ,studies for a 25-ft. dam and a SO-ft. dam were performed for the
critical period only. It is recognized that with a low head dam, the
additibnal storage would convert some of the secondary to firm ~nd ~he
remaining secondary ,.;auld be increased only by the factor of the increased
head. Inasmuch as the total average annual energy would not be increased
significantly "'ith a low head dam, the incremental analysis for i1 low head
dam has been based on firm energy production. Comparisions, assuming
6 percent transmission losse.s on both the capacity and energy components
are as follows:
No Dam (Based on annual firm energy)
Dep. Capacity 27,000 Kw x $39.99 x 0.94
Firm Energy: 103,000,000 Kwh x $0.00991 x 0.94
2S-Ft. Dam (Based on annual firm energy)
Dep. Capacity 27,000 Kw x $39.99 x 0.94
Total
Rounded
Firm Energy: 108,600,000 Kwh x $0.00991 x O. 9Lf
Total
Rounded
Annual incremental limited benefit for 2S-ft. dam
SO-Ft. Dmn (Based on annual ;:irm energYl
Dep. Capacity 27,000 Kw x $39.99 x 0.94
Firm Energy: 11S,200,OOO Kwh x $0.00991 x 0.94
Total
Annual incremental limited bEnefit for SO-ft. dam
$1,014,900
$ 9S9,SOO
$1,974,400
$1,974,000
~;l,014,900
_~:,Oll!7Qi!
:~~,026,600
$!:,027,OOO
s S3,OOO
$1,014,900
$: . 073 100 -.. :.::"::"':"'::-
S2,088,OOO
§ 114,000
24.1S AVERAGE ANNUAL VALUE FOR ONE FOOT OF HEAD. For purposes 0= determin-
ing economical tunnel and penstock sizes, the average annugl value applicable
to head losses has been deter:nined 8S approximately $2, lSO per Ioot. The
value has been determined on the basis of limited benefits as discussed in
the p:.-,·.'vio " "'-"-' -::~),'a:);', T\w mej-hcde, havp. been emrloyed c's a che.d: on the
result. The first met:hod -shown belcM utilizes the limiting benefits, as
determined in the previous paragraph, divided by 25 or 50 feet of additional
head by construction of a low-head dam at the Crater Lake outlet. It is
recognized this is not completely accurate, but is is considered satis-
factory for the intended purposes. The second method employs the average
annual flow multiplied by the conversion factor for one foot of head to
determine the average annual kilowatts per foot of head. Dependable capacity
was computed on the basis of the 53 percent load factor shown in the fore-
casted power requirements (paragraph 24.04). The average of the two methods
result in a value of about $2,150 per foot of head.
a. Method No.1 (Refer to paragraph 24.14).
(1) Annual incremental limited benefit for 25-ft. dam = $ 52,000
$ 2,080 per ft.
(2) A.nnual incremental limited benefit for 50-ft. dam" s1l3,OOO
$ 2,260 per ft.
Average $ 2,170 per ft.
b. Method No.2
Average annual flow = 200 cfs
Average Kw per cfs = 0.070 per ft.
Average energy equivalent == 200 x 0.070
Annual load factor == 53 percent
Dependable capacity = 14 = 26.42 Kw
0.53
Limited Benefit for One-Foot Head:
14 Kw
Dependable Capacity
Ave. Annual Energy
26.42 Kw x $39.99 x 0.94 ==
14 Kw x 8760 x $0.00991 x 0.94 =
Total
$ 99J
$1,142
$2,135
USE
24.16 ANNUAL COSTS WITHOUT A DAM.~rater Lake financial costs include
annual interest and amortization at 3-1/8 percent interest on the total
investment, and annual operation, maintenance and replacement costs over
the 100-year period of analysis. The following tabulation shows the
estimated construction, investment, and annual costs based on July 1973
cost index:
First Cost
Interest during construction (4 yrs. @ 3-1/8%)
Investment Cost
Amortization
Operation & Haintenance
Replacements
Total Anrrual Charges
:::: $25,484,000
= $ 1,592,750
= $27,076,750
$ 887,000
= $ 15,000
= $ 12,000
$ 914,000
a. Beneiit-to-Cost Ratio: Annual power benefits as shown under paragraph
24.12 are $2,593,0000 Annual costs as shown above are $914,000 and the
resultant benefit-to-cost ratio is 2.84 to 1.
b. Comparability Ratio: Annual limited power benefits for Crater Lake
development without a dam as shown under paragraph 24.14 are $1,974,000.
Annual costs as shown in paragraph .24.16 are $914,000 and the resultant
benefit to cost ratio is 2.16 to 1.
pmlER & ENERGY (\EC)LiREJ'lEiHS -SilETTlSHAH PROJECT -JULY 1973 FORECl\ST
Year
1950
1951
1952
1953
1954
1955
1956
1957
l! 195d
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
B70
1971
2/ 1972
3/ 1973
1974
197::)
1976
lr;;77
1978
1979
19dO
19d1
1932
1983
1934
1935
lS86
1987
1 :iS8
1989
1990
Fiscal Year
Energy
KI,JH X 1 GUO
14,800
16,450
18,550
20.4S0
22,000
23,350
23,500
23,800
25,400
27,800
30,700
33,500
35,~ 50
39,250
43,350
45,900
48 ,~GO
51 ,150
54.410
58,180
62,470
69,100
76,300
96,500
121,500
135,900
148)700
162,000
171 ,nuo
136,000
208,OLlO_
227,000
247,uuO
269,000
2;)3.000
319,GOO
342,000
372,LlO(J
411 ,000
447,000
1/ Bill passed for Stutehood.
2/ r\ctual record.
Energy
K\tH X 1000
14,050
15,522
17,364
1~,771
21,108
22,913
23,810
23,193
24,402
26,437
29,156
32,282
34,712
37,150
41,527
43,472
48,283
49,506
52,791
56,029
60,339
64,606
71,732
79,500
113,600
, 29 ,300
142,500
155,000
168,000
173,000
B9,GOO
217.000
236.000
257,000
280,OGO
3J5,000
332 s JOO
3~1,OOO
393.000
428,000
466,000
Calendar Year
net Peak Load Factor
K\J
3,200
3,630
4,090
4,350
5,025
5,030
5,353 .
4,747
5,105
5,4G5
5,837
7,750
7,056
9,044
9,424
10,003
10,859
10,510
11 ,145
11,820
13,010
14,420
15,400
17,130
24,400
27,900
30,400
33,OO!J
36,000
39,200
42,700
46,500
50,600
55,200
60,100
65,400
71,20J
77 ,oJO
84,900
92,000
100,200
of
10
50.1
48.8
48.5
51.9
48.0
52.0
50.8
54.7
54.6
55.2
57.0
47.6
56.0
46.9
50.3
49.5
50.8
53.8
54.5
54.1
52.9
51.1
50.4
53.0
53,0
53.0
53.0
53.0
53.0
53.0
53.0
53.0
53.0
53.0
53.0
53.0
53.0
53.0
53.0
53.0
53.0
"!/ Snettishan; Pi'f):':: in OfjF:ratinn Octo~cr of C.Y. 1'}73.
SECTION 25 -DISCUSSION, CONCLUSIONS AND RECOMMENDATION
25.01 DISCUSSION. The plan of dev~lopment for the Crater Lake Phase of
the Snettisham Project has been formulated with consideration of the experi-
ences gained in the development of the Long Lake Phase of the project and
the experiences of others in the de-"elopment of similar projects, primarily
in Europe. The changes from the recommendations in Design Memorandum No. 3
are:
a. Tap directly into the power t-J.nnel, eliminating the separate diversion
tunnel;
b. Install the emergency gate in the tunnel, downstream from the lake,
eliminating the intake structures;
c. Eliminate the concrete power tunnel lining;
d. Place the powerhouse underground.
25.02 The concepts for the development of Crater Lake, as origiGally pre-
sented in Design Memorandum No.3, have been studied and are presented in
this design memo as the Intake Structure Alternative. A third basic concept,
the Power/Access Tunnel Alternative was studied and compared with the re-
commended plan, as were several variations in gate structures for the re-
commended plan.
25.Q3 CONCLUSIONS. The Power/Access Tunnel Alternative has the least
impact on the existing environment and the Intake Structure Alternative
has the greatest environmental impact. The only essential difference in
environmental impact between the Power/Access Tunnel Alternative and the
Recommended Plan is the extent of access road construction.
25.04 The Intake Structure Alternative providp.s a means of unwatering
the entire power tunnel and a means of drawing the lake level down, if
required because of seismic damage to the upper end of the POWE::l' tunnel.
25.05 The Recorrnnended Plan is feasible where the dangers of seismic dis-
turbances, disrupting the project operation, are minimal, and where there
is almost no debris problem in the reservoir. Of the alternatives considered
technically feasible and warranting detailed studies, the Recommended Plan
is the most economical.
25.06 Two different height dams were investi.gated to inCl"CaSe storage at
Crater Lake. Neither one is economically justified at this time. The
suspected foundation conditions at the lake outlet could result in the cost
of either dam being more expensive than indicated in this report. Develop-
ment of Crater Lake as presented in this report will further increase the
costs of later dam construction because the power tunnel, penstock, surge
tank and powerhouse facilities will not be adequate for che increased operat-
ing head that would result.
25.07 RECOMMENDATION. The District Engineer recommends that the Crater Lake
Phase of the Snettisham Project be a~proved for construction in accordance
with the Recommended Plan of Development presented in this design memorandum.
SNETTISHAH PROJECT, ALASKA
RECOMt£NDED PLAN
TABLE j -SUH'1ARY COST ESTIHATE
Price Level -Sept 1973
FIRST STAGE DEVELOPNENT. CRATER LAKE PHASE
Feature or Item
04 DAM
04.4 Power Intake Works
Gate Structure
Power Tunnel and Rock Trap
Lake Tap and Rock Trap
Surge Tank
Penstock
Gate Structure Access Adit
Surge Tank Access Adit
Amount
$ 2,018,000
7,104,000
821,000
642,000
3,476,00C
2,168,00C
1,054,00Q
Total Cost, 04.4 Power Intake Works $17,283,000
Total
TOTAL COST, 04 DAM ~ 17,283,000
07 POWER PLANT
07.1
07.2
0'J.3
07.3
07.8
Powerhouse
Turbines and Generators
Accessory Electrical Equipment
Switchyard
Transmission Plant
TOTAL COST, 07 POWER PLANT
08 ACCESS ROADS
19 BUILDINGS, GROUNDS. UTILITIES
Buildings
Grounds
Utilities
$ 287,000
2,526,00Ll
14i,OUU
177.000
12,000
$ 3,144, 000
$ 8'., oeo
35,000
_--.-!!J.. 6 ) 00 I!
$ 3,144, ono
639,000
TOTAL COST, 19 BUILDING~ GROUND~ UTILITIES $ 595,000 $ 595,000
TOTAL COST, TABLE 1 $21,661, 000
TABU: 1
;;ll;i~:~~ t: :).t 1
SNETTISHAM PROJECT, ALASKA
INTAKE STRUCTURE ALTERNATIVE
TABLE 2 -SUW1ARY COST ESTIMATE
Price Level -Sept 1973
FIRST STAGE DEVELOPMENT, CRATER LAKE PHASE
Feature or Item
04 DAM
04.4 Power Intake Works
Intake Structure
Power Tunnel and Rock Trap
Surge Tank
Penstock
Surge Tank Access Adit
Amount
$ 3,466,000
7,104,000
642,000
3,476,000
1,054,000
Total Cost, 04.4 Power Intake Works $15,742,000
Total
TOTAL COST, 04 DAM $15,742,000
07 POWER PLANT
07.1 Powerhouse
07.2 Turbines and Generators
07.3 Accessory Electrical Equipment
97.3 Switchyard
TOTAL COST, 07 POWER PLANT
08 ACCESS ROADS
Intake Structure Access Road
Diversion Access
Surge Tank Access Adit Road
TOTAL COST, 08 ACCESS ROADS
19 BUILDINGS, GROUNDS AND UTILITIES
Buildings
Grounds
Utilities
$ 287,000
2,526,000
141,000
177 ,000
$ 3,131,000
$ 1,176,000
283,000
160,000
$ 1,619,000
$ 84,000
35,000
180,000
$ 3,131,000
$ 1,619,000
TOTAL COST, 19 BUILDINGS, GROUNDS, UTILITIES 299,000 $ 299,000
TABLE 2
Sheet 1 of 2
FIRST STAGE DEVELOPMENT, CRATER LAKE PHASE Continued
Feature or Item
50 CONSTRUCTION FACILITIES (DIVERSIO~
TOTAL COST, TABLE 2
Amount Total
$ 2,346,000
$23,137,000
TABLE 2
Sheet 2 of 2
SNETTISHAM PROJECT, ALASKA
POWER/ACCESS TUNNEL ALTERNATIVE
TABLE 3 -SUHMARY COST ESTIMATE
Price Level -Sept 1973
FIRST STAGE DEVELOPMENT, CRATER LAKE PHASE
Feature or Item
04 DAM
04.4 Power Intake Works
Gate Structure
Power Tunnel/Access Tunnel
Lake Tap and Rock Trap
Surge Tank
Penstock
Surge Tank Access Adit
Total Cost, 04.4 Power Intake Works
TOTAL COST, 04 DAM
07 POWER PLANT
07.1 Powerhouse
07.2 Turbines and Generators
07.3 Accessory Electrical Equipment
07.3 Switchyard
TOTAL COST, 07 POWER PLANT
08 ACCESS ROADS
19 BUILDINGS, GROUNDS, UTILITIES
Buildings
Grounds
Utilities
Amount
$ 2,006,000
17,504,000
821,000
684,000
3,476,000
1,054,000
$25,547,000
$
$
$
287,000
2,526,000
141,000
177 ,000
3,131,000
84,000
35,000
245,000
TOTAL COST, 19 BUILDINGS, GROUND~ UTILITIES $ 364,000
TOTAL COST, TABLE 3
Total
$25,547,000
$ 3,131,000
$ 160,000
$ 364,000
$29,202,000
TABLE 3
Sheet 1 of 1
SNETTISHAM PROJECT, ALASKA
RECOMNENDED PlAN
TABLE 4 -DETAILED COST ESTIMATE
Price Level -Sept 1973
FIRST STAGE DEVELOPMENT. CRATER lAKE PHASE
Feature or Item Unit Quantity
04 DAM
04.4 Power Intake Works
Gate Structure
Slide Gates & Machinery Ea.
Miscellaneous Metal Lb.
Crane, 20-Ton Monorail
& Track
Vent Pipe
Access Manhole
Concrete
Reinforcing Steel
Excavation, Rock
Vent Shaft, 36" Dia.
Subtotal
Contingency 20%
Total Cost, Gate Structure
Power Tunnel and Rock Trap
Excavation, Rock
Concrete
Reinforcing Steel
Rock Bolts
Steel Sets
Shotcrete
Subtotal
Contingency 20%
Ea.
L.F.
Ea.
C.Y.
Lb.
C.Y.
L.F.
L.F.
C.Y.
Lb.
L.F.
Ra.
e.F.
2
10,000
1
1,200
1
600
30,000
1,250
250
6,100
420
250,000
21,400
5
1,000
Total Cost, Power Tunnel & Rock Trap
Lake Tap and Rock Trap
Excavation, Rock
Concrete
Reinforcing Steel
L.F.
C.Y.
Lb.
130
15
1,000
Unit
Price
$400,000.00
2.25
$
30,000.00
60.00
3,000.00
675.00
0.75
190.00
350.00
800.00
520.00
0.75
20.00
1,200.00
200.00
$ 1,300.00
675.00
0.75
TABLE 4
Sheet 1 of 6
$
Amount
800,000
23,000
30,000
72,000
3,000
405,000
23,000
238,000
88,000
$ 1,682,000
336,000
$ 2,018,000
$ 4,880,000
218,000
188,000
428,000
6,000
200,000
$ 5,920,000
1,184,000
$ 7,104,000
$ 169,000
10,000
1,000
FIRST STAGE DEVELOPMENT 1 CRATER LAKE PHASE Continued
04 DAM Continued
Feature or Item Unit
04.4 Power Intake Works Continued
Lake Tap and Rock Trap Continued
Steel Trashrack Ea.
Rock Bolts L.F.
Lake Tap Job
Subtotal
Contingency 20%
Total Cost, Lake Tap & Rock Trap
Surge Tank
Excavation, Rock (Shaft) L.F.
Excavation, Rock (Drift) L.F.
Concrete c.y.
Reinforcing Steel Lb.
Steel Orifice Lb.
Rock Bolts L.F.
Wire Mesh S.Y.
Subtotal
Contingency 20%
Total Cost, Surge Tank
Penstock
Excavation, Rock L.F.
Concrete c.y.
Reinforcing Steel Lb.
Steel Liner Lb.
Rock Bolts L.F.
Subtotal
Contingency 20%
Total Cost, Penstock
Gate Structure Access Ad it
Excavation, Rock c.y.
Concrete c.y.
Steel Door Lb.
Quantity
1
200
1
400
40
57
3,500
700
4,000
1,000
1,590
1,400
11,000
907,000
350
8,570
3
1,000
Unit
Price
$100,000.00
20.00
400,000.00
$ 950.00
500.00
675.00
0.75
2.25
20.00
12.00
$ 614.00
260.00
0.75
1. 70
20.00
$ 200.00
700.00
2.25
TABLE 4
Sheet 2 of 6
Amount
$ 100,000
4,000
400,000
$ 684,000
137 ,000
$ 821,000
$ 380,000
20,000
38,000
3,QOO
2,000
80,000
12 2 000
$ 535,000
107,000
$ 642,000
$ 976,000
364,000
8,000
1,542,000
7 2 000
$ 2,897,000
579 2 °00
$ 3,476,UOO
$ 1,714,000
2,000
2,000
FIRST STAGE DEVELOPMENT, CRATER LAKE PHASE Continued
04 DAM Continued
Feature or Item . Unit Quantity
04.4 Power Intake Works Continued
Gate Structure Access Adit Continued
Rock Bolts L.F.
Wire Mesh
Subtotal
Contingency 20%
S.y.
4,378
17
Total Cost, Gate Structure Access Adit
Surge Tank Access Adit
Excavation, Rock
Concrete, Plug
Reinforcing Steel
Steel Gate
Rock Bolts
Wire Mesh
Subtotal
Contingency 20io
C.y.
c.y.
Lb.
Lb.
L.F.
S.Y.
Total Cost, Surge Tank Access Adit
Total Cost, 04.4 Power Intake Works
TOTAL COST, 04 DAM
07 POWER PLANT
07.1 Powerhouse
Concrete, Substructure C.Y.
Concrete, Superstructure C.Y.
Concrete, Penstock Braxh C.Y.
Cement CWT
Reinforcing Steel Lb.
Painting Arch. Features L.S.
Painting, Equipment L.S.
Piping Systems L.S.
Heating & Ventilating L.S.
Dust Protection and
Barricading
Misc. Metals
Bulkhead Guides, 300
L. S.
Lb.
S ss Lb.
3,400
310
4,300
10,000
800
17
204
73
66
1,615
33,000
5,100
300
$
$
Unit
Price
20.00
12.00
200.00
500.00
0.75
2.25
20.00
12.00
$ 365.00
540.00
100.00
4.30
Oe75
7,000.00
10,000.00
22,000.00
1,000.00
5,000.00
2.80
1.80
TABLE 4
Sheet 3 of 6
$
Amount
88,000
1,000
$ 1,807,000
361,000
$ 2,168,000
$
$
680,000
155,000
3,000
23,000
16,000
1,000
878,000
176,000
$ 1,054,000
$17 , 283,000
$17,283,000
$ 74,000
39,000
7,000
7,000
2),000
7,000
10,000
22,000
1,000
5,000
14,000
1,000
FIRST STAGE DEVELOPMENT, CRATER LAKE PHASE Continued
07 POWER PLANT Continued
Feature or Item Unit Quantity
07.1 Powerhouse Continued
Penstock Branch A516 Lb. 26,400
Electrical L.S.
Subtotal
Contingency 20%
Total Cost, 07.1 Powerhouse
07.2 Turbines and Generators
Turbine Ea. 1
Generator Ea. 1
Governor Ea. 1
Spherical Valve Ea. 1
Subtotal
Contingency 20%
Total Cost, 07.2 Turbines and Generators
07.3 Accessory Electrical EguiEment
15 KV & Control Equip. L.S.
Misc. Electrical Equip. L.S.
Subtotal
Contingency 20%
$
Unit
Price
0.90
3,000.00
$830,000.00
840,000.00
95,000.00
340,000.00
$ 65,000.00
53,000.00
Total Cost, 07.3 Accessory Electrical Equipment
07.3 Switchyard
Excavation C.Y. 285 $ 3.00
Concrete Foundation C.Y. 10 300.00
Reinforcing Steel Lb. 1,500 0.75
Transformer Ea. 1 123,000.00
High Voltage Equipment L. S. 20,000.00
Subtotal
Contingency 20%
Total Cost, 07.3 Switchyard
07.8 Transmission Plant
Status Switchboard L.S. $ 10,000.00
Contingency 201'0
Total Cost, 07.8 Transmission Plant
TOTAL COS'i', 07 PO~JERPLANT
TABLE 4
Sheet 4
Amount
$ 24,000
$ 239,000
48,000
$ 287,000
$ 830,000
840,000
95,000
340,000
$ 2,105,000
421,000
$ 2,526,000
$ 65,000
53,000
$ 118,000
23 z000
$ 141,000
$ 1,000
3,000
1,000
123,000
20 2 000
$ 148,000
30 2 000
$ 178,000
$ 10,000
2 2 000
$ 12,000
$ 3,144,000
of 6
FIRST STAGE DEVELOPMENT I CRATER LAKE PHASE Continued
Unit
Feature or Item UnH Quantity Price Amount --
08 ACCESS ROADS
Upper Access Road
Excavation, Rock C.Y. 26,870 $ 10.00 $ 269,000
Clearing Acre 2.9 7,000.00 20,000
Fill, Rock c.y. 12,827 1.00 13,000
Fill, Select c.y. 4,873 5.00 24,000
Guardrail L.F. 4,150 15.00 62,000
Slope Dressing Acre 0.4 7,000.00 3,000
CMP, 24" Diameter L.F. 90 30.00 3,000
CMP, 12" Diameter L.F. 300 15.00 5,000
Subtotal $ 399,000
Contingency 20% 80,000
Total Cost, Upper Access Road $ 479,000
Surge Tank Access Adit Road
Excavation, Rock C.Y. 9,730 $ 10.00 $ 97,000
Clearing Acre 1 7,000.00 7,000
Surfacing, Gravel C.Y. 1,300 5.00 7,000
Guardrail L.F. 1,450 15.00 22,000
Subtotal $ 133,000
Contingencies 20% 27,000
Total Cost, Surge Tank Access Adit Road $ 160,000
TOTAL COST, 08 ACCESS ROADS $ 639,000
19 BUILDINGS I GROUNDS, UTILITIES
Buildings
Transmission Maint. Bldg. Job 1 $ 43,000.00 $ 43,000
Picnic Shelter Job 1 27,000.00 27,000
Subtotal $ 70,000
Contingency 20% 14,000
Total Cost, Buildings $ 84,000
Grounds
Landscaping Job 1 $ 29,000.00 $ 29,000
Contingency 20% 6,000
Total Cost, Grounds $ 35,000
TABLE 4
Sheet 5 of .6
FIRST STAGE DEVELOPMENT, CRATER LAKE PHASE Continued
Feature or Item Unit Quantity
19 BUILDINGS. GROUNDS, UTILITIES Continued
Utilities
Sewage Lagoon Gal. 400,000 $
Contingency 20%
Total Cost, Sewage Lagoon
Power Line
Power Cable L.F. 1,250 $
Overhead Line L.F. 6,225
Subtotal
Contingency 20%
Total Cost, Power Line
Total Cost, Utilities (Sewage Lagoon & Power Line)
TOTAL COST, 19 BUILDINGS, GROUNDS, UTILITIES
TOTAL COST, CONSTRUCTION, TABLE 4
Unit
Price Amount
0.65 $ 260,000
52,000
$ 312,000
28.00 $ 35,000
16.40 $ 102.000
$ 137,000
27 2 000
$ 164,000
$ 476,000
$ 595,000
$21,661,000
TABLE 4
Sheet 6 of 6
SNETTISHAM PROJECT, ALASKA
ALTERNATIVES
TABLE 5 -DETAILED COST ESTIMATE
Price Level -Sept 1973
FIRST STAGE DEVELOPMENT, CRATER LAKE PHASE
Feature or Item
GATE STRUCTURE ALTERNATIVES
Gate Structure
Slide Gates
Misc. Metal
Crane, 1S-Ton Monorail
with Track
Vent Pipe, 30" Diameter
Access Manhole
Concrete, Base
Concrete, Shaft Lining
Excavation, Rock
Gate Chamber
Shaft
Elevator, 1,000-Lb. Cap.
Subtotal
Contingency 20%
Unit Quantity
Ea. 2
Lb. 10,000
Ea. 1
L.F. 260
Ea. 1
c.y. 800
c.y. 1,530
c.y. 4,700
c.y. 4,800
Ea. 1
Total, Cost, Dry Well with 2 Slide Gates
Dry Well with Bulkhead §. Slide Gate
Slide Gate Ea. 1
Bulkhead Ea 1
Misc. Metal Lb. 10,000
Crane, Monorail & Track Ea. 1
Vent Pipe, 30" Diameter L.F. 260
Access Manhole Ea. 1
Concrete, Base c.y. 800
Concrete, Shaft c.y. 1,530
Excavation, Rock
Gate Champer c.y. 4,700
Shaft c.y. 4,800
Elevator, 1,000-Lb Cap. Ea. 1
Gate Valve, Quick Opening
12" 9) Ea. 1
Unit
Price
$400,000.00
2.25
30,000.00
60.00
3,000.00
675.00
450.00
190.00
130.00
40,000.00
$420,000.00
40,000.00
2.25
30,000.00
60.00
3,000.00
675.00
450.00
190.00
130.00
40,000.00
2,000.00
TABLE 5
Sheet 1 of 7
Amount
$ 800,000
23,000
30,000
16,000
3,000
540,000
689,000
893,000
624,000
40,000
$ 3,658,000
731,000
$ 4,389,000
$ 420,000
40,000
23,000
30,000
16,000
3,000
540,000
689,000
893,000
624,000
40,000
2,000
FIRST STAGE DEVELOPMENT, CRATER LAKE PHASE Continued
Feature or Item Unit Quantity
GATE STRUCTURE ALTERNATIVES Continued
Dry ~ with Bulkhead ~ Slide Gate Continued
Subtotal
Contingency 20'7.
Total Cost, Dry Well with Bulkhead & Slide Gate
Wet Well with Bulkhead & Slide Gate
Slide Gate
Crane, Monorail & Track
Bulkhead
Vent Pipe, 30" Diameter
Concrete, Tunnel Lining
Concrete, Bulkhead Slot &
Chamber
Concrete, Slab (E1. 1040)
Excavation, Rock
Chamber
Shaft
Gate Valve, Quick Opening
2000 psi, 12" 0
Subtotal
Contingency 20%
Ea.
Ea.
Ea
L.F.
C.Y.
C.Y.
C.Y.
C.Y.
C.Y.
Ea.
1
1
1
260
260
960
10
4,700
1,200
1
Total Cost, Wet Well with Bulkhead and Slide Gate
Wet Well with Bulkhead and Tainter Gate
Excavation, Rock
Gate Chamber
Shaft
Concrete
Power Tunnel
Gate Chamber
Bulkhead Slot
Bulkhead Gate
Tainter Gate
Gate Hoist
Monorail Hoist
Gate Valve
c.y.
c.y.
c.y.
c.y.
c.y.
Ea.
Ea.
Ea
Ea.
Ea.
4,700
3,410
260
160
620
1
1
1
1
1
Unit
Price
$420,000.00
30,000.00
40,000.00
60.00
520.00
$
675.00
700.00
190.00
130.00
2,000.00
190.00
130.00
520.00
675.00
700.00
40,000.00
150,000.00
30,000.00
30,000.00
2,000.00
TABLE 5
Sheet 2 of 7
Amount
$ 3,320,000
664,000
$ 3,984,000
$ 420,000
30,000
40,000
16,000
135,000
648,000
7,000
893,000
156,000
2,000
$ 2,347,000
469,000
$ 2,816,000
$ 893,000
443,000
l35,000
108,000
434,000
40,000
150,000
30,000
30,000
2,000
' ...
FIRST STAGE DEVELOPMENT z CRATER LAKE PHASE Continued
Unit
Feature or Item Unit Quantity Price
GATE STRUCTURE ALTERNATIVES Continued
Wet Well with Bulkhead and Tainter Gate Continued --------
Subtotal
Contingency 20%
Total Cost, Wet Well with Bulkhead and Tainter Gate
Wet Well with Bulkhead and Tractor Gate -------
Excavation, Rock
Gate Chamber C.Y. 4,700 $ 190.00
Shaft C.Y. 1,850 130.00
Concrete
Power Tunnel C.Y. 260 520.00
Gate Chamber C.Y. 90 675.00
Shaft Lining C.Y. 80 700.00
Vent Pipe, 30" Diameter L.F. 260 60.00
Tractor Gate Ea. 1 150,000.00
Gate Hoist Ea. 1 30,000.00
Monorail Hoist Ea. 1 30,000.00
Bulkhead Gate Ea. 1 40,000.00
Gate Valve Ea 1 2,000.00
Subtotal
Contingency 20%
Total Cost, Wet Well with Bulkhead and Tractor Gate
TWO-STEP LAKE TAP
Excavation, Rock
Rock Traps C.Y.
Power Tunnels L.F.
Concrete C.Y.
Trash Racks Ea.
Rock Bolts L.F.
Lake Tap Job
Subtotal
Contingency 20%
TOTAL COST, TWO-STEP LAKE TAP
1,060
310
20
2
400
1
$ 200.00
800.00
675.00
100,000.00
21.00
500,000.00
TABLE 5
Sheet 3 of 7
Amount
$ 2 .. 265,000
453,000
$ 2,718,000
$ 893,000
241,000
135,000
61,000
56,000
16,000
150,000
30,000
30,000
40,000
2 z000
$ 1,654,000
331 2 000
$ 1,985,000
$ 212,000
248,000
16,000
200,000
8,000
500 2 000
$ 1,184,000
237 2 000
$ 1,421,000
FIRST STAGE DEVELOPMENT, CRATER LAKE PHASE Continued
Feature or Item
DIVERSION
Diversion Tunnel
Excavation, Rock
Concrete
Slide Gate
She 1ter
Lake Tap
Subtotal
Contingency 20%
Total Cost, Diversion Tunnel
Diversion Tunnel Access Road
Clearing
Excavation, Rock
Embankment, Rock
Surfacing, Gravel
CMP, 12" Diameter
CMP, 24" Diameter
Guardrail
Subtotal
Contingency 20%
Unit Quantity
L.F.
C.Y.
Ea.
Ea.
Job
Acre
C.Y.
C.y.
C.Y.
L.F.
L.F.
L.F.
1,650
250
1
1
1
3
14,000
10,000
3,000
200
60
3,000
Total Cost, Diversion Tunnel Access Road
TOTAL COST, DIVERSION
INTAKE AT lAKE
Intake Structure
Excavation, Rock
Concrete
Elevator
Slide Gate
Misc. Metal
Vent Pipe, 20" Diameter
Hoist, 1/2 Ton
Trashrack
Access Manhole
Bulkhead Gate
Gate Valve, Quick Opening
12" 0
Bridge, Steel
C.y.
C.Y.
Ea.
Ea.
Lb.
L.F.
Ea.
Lb.
L.S.
Ea.
Ea.
Lb.
6,200
3,430
1
1
2,400
440
1
21,000
1
1
1
91,000
Unit
Price
$ 600.00
520.00
420,000.00
15,000.00
400,000.00
$ 7,000.00
10.00
1.00
5.00
15.00
30.00
15.00
$ 35.00
550.00
40,000.00
420,000.00
2.25
50.00
5,000.00
2.00
3,000.00
40,000.00
2,000.00
2.25
TABLE 5
Sheet 4 of 7
$
Amount
990,000
130,000
420,000
15,000
400,000
$ 1,955,000
391,000
$ 2,346,000
$
$
$
21,000
140,000
10,000
15,000
3,000
2,000
45,000
236,000
47,000
283,000
$ 2,623,000
$ 217,000
1,887,000
40,000
420,000
5,000
22,000
5,000
42,000
3,000
40,000
2,000
205,000
FIRST STAGE DEVELOPMENT I CRATER LAKE PHASE Continued
Feature or Item Unit Quantity
INTAKE AT LAKE Continued
Intake Structure Continued
Subtotal
Contingency 20%
Total Cost, Intake Structure
Intake Structure Access Road
Clearing Acre 6
Excavation, Rock c.y. 72,000
Embankment, Rock c.y. 51,000
Surfacing, Gravel c.y. 8,000
CMP, 12" Diameter L.F. 600
CMP, 24" Diameter L.F. 120
Guardrail L.F. 7,575
Subtotal
Cont ingency 20%
Total Cost, Intake Structure Access Road
Power Line to Intake
Power Cable L.F.
Overhead Power Line L.F.
Subtotal
Cont ingency 2070
Total Cost, Power Line to Intake
POWER/ACCESS TUNNEL ALTERNATIVE
Gate Structure
Slide Gates & Machinery
Miscellaneous Metal
Crane, 20-Ton, Monorail &
Track
Vent Pipe, 30" Diameter
Access Manhole
Concrete
Reinforcing Steel
Excavation, Rock
Vent Shaft, 36" Diameter
Ea.
Lb.
Ea.
L.F.
Ea.
c.y.
Lb.
c.y.
L.F.
300
8,400
2
10,000
1
1,300
1
540
40,000
1,250
300
Unit
Price
$ 7,000.00
10.00
1.00
5.00
15.00
30.00
15.00
$ 28.00
16.90
$400,000.00
2.25
30,000.00
60.00
3,000.00
675.00
0.75
190.00
350.00
TABLE 5
Sheet 5 of 7
e ..
Amount
$ 2,888,000
578,000
$ 3,466,000
$ 42,000
720,000
51,000
40,000
9,000
4,000
114,000
$ 980,000
196,000
$ 1,176,000
$ 8,000
142,000
$ 150,000
30,000
$ 180,000
$ 800,000
23,000
30,000
78,000
3,000
365,000
30,000
238,000
105,000
FIRST STAGE DEVELOPMENT 2 CRATER LAKE PHASE Continued
Feature or Item Unit --Quantity
POWER/ ACCESS TUNNEL ALTERNATIVE Continued
Gate Structure Continued
Subtotal
Contingency 20%
Total Cost, Gate Structure
Power/Access Tunnel
Excavation, Rock
Sta. 7+00 to 14+00 L.F. 700
Sta. 14+00 to -65+65 L.F. 5,165
Concrete c.y. 22,960
Steel Lb. 1,988,000
Rock Bolts L.F. 21,400
Steel Sets Ea. 5
Subtotal
Contingency 20%
Total Cost, Power/Access Tunnel
Surge Tank
Excavation, Rock
Shaft L.F. 400
Drift L.F. 40
Concrete
@ Top C.Y. 57
@ Drift c.y. 42
Reinforcing Steel Lb. 3,500
Structural Steel Lb. 16,100
Rock Bolts L.F. 4,000
Wire Mesh s.y. 1,000
Subtotal
Contingency 20%
Total Cost, Surge Tank
Unit
Price
$ 800.00
860.00
260.00
1. 60
20.00
1,200.00
$ 950.00
500.00
675.00
260.00
0.75
1.60
20.00
12.00
TABLE 5
Sheet 6 of 7
Amount
$ 1,672 ,000
334,000
$ 2,006,000
$ 560,000
4,442,000
5,970,000
3,181,000
428,000
6,000
$14,587,000
2 2 917 2 000
$17,504,000
$ 380,000
20,000
38,000
11,000
3,000
26,000
80,000
12 2 000
$ 570,000
114 2 000
$ 684,000
FIRST STAGE DEVELOPMENT, CRATER LAKE PHASE Continued
Feature or Item UnH Quantity
POWER/ACCESS TUNNEL ALTERNATIVE Continued
Power Line
Power Cable L.F. 5,800
Overhead Power Line L.F. 2,500
Subtotal
Contingency 207.
Total Cost, Power Line
$
Unit
Price
28.00
16.90
TABLE 5
Sheet 7 of 7
Amount
$ 162,000
42,000
$ 204,000
41,000
$ 245,000
Pigure.s
FIGUF~E 2
1,IYJ'O:C.lJGlCAL DII'!1\.
CRA TER L.r.Kl
DAn; S1:ATION DEPTH W'll ter Temp. D02 CO2 UCO) pH See chi ::::01;:'1
ft. 0 F. PPM PPM Pf'H Llsk ---..... -~~''"'" ......... _-< ........ ..-,-_ .. _ ... '--. .--~ .... ,-'--'--
8-l8-S8 1 0 56.0 10,9 4.0 LU Greenish
Hue
8-18-58 1 136 44.0 11.6 5.0 6.9 2 l. it.
8-18-58 272 44.0 10.2 4.4 6.0
8-18-58 1 4W 45.0 9.6 9.1 6.8
(Bottom)
-------- -
---. .. -~ ----. . .
8-29-59 2 i) 51.5 11 . .1, 1.1 9.9 G~'~a!H18h
BLue
8-29-59 2 160 43.0 11.1 1.4 8.4 i , ':I It.
8-29-59 2 320 43.0 10.5 1.6 6.9
(Bottom)
It Source of D.:.ta; Bux'eau of Sport Fisheries & Wildlife and /';ational t\8rLH! }'li;hedu Service
.~. : .,
.. -':'--1
FIGURE 3
SNETTISHAM PROJECT, ALASKA
SNOW SURVEY DATA
MARCH 1 APRIL 1 MAY 1 J~"'E 1
SNOW WATER SNOW WATER SNOW WATER S~OW WATER
DEPTH EQUIV DEPTH EQUIV DEPTH EQUIV DEPTH EQUIV
YEAR DATE IN. IN. DATE IN. IN. DATE IN. IN. DATE IN. IN. --
CRATER LAKE (Elevation 1,750 feet)
1965 3/ 3 138 54.0 4/ 1 112 37.0 4/30 117 54 .. 0 6/ 5 92 52.0
1966 3/ 2 162 59.0 3/31 171 80.5 4/30 170 83.5 5/31 100 54.7
1967 3/ 1 198 68.0 3/30 182 74.5 5/ 1 168 81.0
1968 2/29 72 23.8 3/29 84 29.4 4/29 96 4302 6/ 6 48 24.0
1969 2/28 163 69.0 4/ 1 186 87.0 5/ 1 148 77 .0 5/29 115 65.0
1970 3/ 2 107 50.0 4/ 1 126 56.0 5/ 3 154 70.0 5/28 168 78.0
1971 2/25 149 44.4 4/ 5 166 70.5 4/28 155 74.0 129 69.0
1972 3/ 1 160E 64.0E NO SURVEY 5/ 3 152 72.8 5/30 158 87.0
LONG LAKE (Elevation 1,080 feet)
1965 3/ 3 110 36.6 4/ 1 91 34.0 4/30 85 41.6 6/ 5 47 23.6
1966 3/ 2 114 38.2 3/31 119 47.4 4/30 103 47 .. 8 5/31 69 34.2
1967 3/ 1 168 56.4 3/30 150 53.8 5/ 1 129 58.6
1968 2/28 63 21.6 3/29 87 27.3 4/29 93 39.8 6/ 6 9 4.0
1969 2/28 104 35.6 4/ 1 109 44.8 5/ 1 83 36.8 5/29 32 16.0
1970 3/ 2 76 30.0 4/ 1 91 37.6 5/ 3 96 40.6 5/28 56 28.0
1971 2/25 123 38.8 4/ 5 135 52.0 4/28 128 55.0 96 44.6
1972 3/ 1 128 46.8 3/31 1t.1 55.7 5/ 3 136 60.4 5/30 94 47.6
SPEEL RIVER (Elevation 280 feet)
1965 3/ 3 92 33.8 4/ 1 73 31.0 4/30 64 29.2 6/ 5 22 10.0
1966 3/ 2 96 30.9 3/31 98 38.6 4/30 74 34.0 5/31 32 14.2
1967 3/ 1 105 38.2 3/30 106 39.6 5/ 1 79 37.1
1968 2/28 48 17.0 3/29 52 19.5 4/29 50 21..4 6/ 6 0 0.0
1969 2/28 77 24.4 4/ 1 74 27.8 5/ 1 43 20.4 5/29 0 0.0
1970 3/ 2 37 16.0 4/ 1 37 15.4 5/ 3 28 13.2 5/28 0 0.0
1971 2/25 97 29.1 4/ 5 104 40.0 4/28 88 41..6 56 25.6
1972 3/ 1 112 40.3 3/31 116 41.6 5/ 3 108 48.8 5/30 69 34.8
UPPER LONG LAKE (Elevation 1,000 feet)
1965 3/ 3 74 29.0 4/ 1 63 28.0 4/30 57 29.0 6/ 5 26 14.0
1966 3/ 2 103 35.0 3/31 no 45.0 4/30 100 46.2 5/31 76 38.5
1967 3/ 1 155 49.3 3/30 138 51.3 5/ 1 120 59.0
1968 2/28 48 16.7 3/29 72 25.2 4/29 84 36.,1 6/ 6 12 5.0
1969 2/28 97 30.7 4/ 1 107 43.0 5/ 1 85 40.3 5/29 42 21.5
1970 3/ 2 65 25.0 4/ 1 79 35.0 5/ 3 94 40 .. 0 5/28 56 27.7
1971 2/25 109 36.0 4/ ') ]28 51.0 4/28 ll8 53 .. 0 42.9
1972 3/ 1 ll9 43.0 3/31 126 53.3 5/ 3 123 59.0 5/30 88 52.0
E -Estimated FIGURE 3
FI GURE 4
LO~G RIVER SE:JlHENTATION DATA
Station 15-0310 Station 15-0520
. ___ . __ ._.~~~..& __ ~l~er~~\~~ve Lon..s Lake Long .. Ri~~E __ l)_~l.9Y Long Lake ___
Water Suspended Suspended Suspended Suspended
Temperature Discharge Sedioents Sediments Discharge Sediments Sediments
Date °c c. f. s. _tn.~_ tons/d~ c.f.s. mdl tons/daY --------_.-M ____ .~ __ ----------"'--
.3 Oct 67 3, 36. 12 1.2
19 Dec 67 1" 9.8 2 .05 III .3 .9
29 Mar 68 2. 8.8 2 .05
29 Apr 68 2. 13. 1 .04
22 Jul 68 5. 233. 96 60. 715 8 20.
1 Oct 68 3. 84. 14 3.2
1 Apr 69 O. 2.3 2 .01
1 May 69 1. 25. 2 .14 183 2 .99
29 May 69 2. 14l. 8 3.0
8 Jul 69 945. 569 1450.
16 Jul 69 I~ • 155. 88 37.
8 Aug 69 4. 241. 182 118.
18 Sep 69 4. 67. 39 7.1
18 Dec 69 .5 11.4 4 .12
2 Mar 70 11.5 2 .06 6.6 1 .02
1 Apr 70 1.S 11. 9 .3 .10
28 May 10 1.5 96. 7 1.8
21 Jui 70 2. 205. 22 12.
FIGURE 5
CRATER CREEK AT CRATER LAKE OUTLET
AVERAGE MONTHLY FLOWS IN CFS BASED ON CORRELATION STUDIES
Water Year Oct Nov Dec Jan Feb Mar Apr May Jun Ju1 Aug ~
1913 47 48 57 203 531 830 858 491
1914 260 108 38 21 45 37 53 144 272 517 409 266
1915 313 104 24 36 17 45 74 235 414 497 469 389
1916 185 45 33 18 18 19 44 90 370 370 464 470
1917 270 51 33 35 45 23 24 142 305 441 539 361
1918 251 250 35 33 17 13 21 129 347 482 591 411
1919 202 133 65 68 15 12 47 118 217 417 511 420
1920 209 67 45 100 35 16 20 53 177 406 532 262
1921 140 92 25 24 31 24 34 138 305 399 360 297
1922 290 75 95 34 10 10 35 145 287 437 471 352
1923 202 158 41 21 28 38 47 160 297 452 483 502
1924 230 198 77 28 17 30 39 229 400 584 566 581
1927 197 124 95 35 27 25 38 161 350 377 357 352
1928 135 48 25 89 31 40 42 193 381 528 377 343
1929 194 113 82 76 19 49 29 92 382 419 404 347
1930 463 222 60 5 9 15 34 104 308 420 484 359
1931 225 256 146 68 102 22 45 211 402 417 474 361
1932 334 73 28 20 20 15 33 105 284 362 366 429
1933 316 42 27 14 13 15 66 211 230 379 367 252
1934 219 170 43 7 12 18 31 100 371 420 565 342
1935 296 92 67 15 10 20 30 90 251 6.06 418 276
1936 274 66 97 16 13 21 42 194 462 454 371 467
1937 762 294 127 26 16 23 35 112 436 379 411 465
1938 615 96 62 55 43 46 32 225 309 423 333 535
1939 327 84 68 37 26 20 33 124 337 520 608 353
1940 373 151 89 28 38 15 43 205 323 485 560 433
1941 311 79 43 15 25 24 51 166 372 491 293 202
1942 276 166 75 40 33 36 37 158 425 538 536 393
1943 361 61 42 45 21 33 56 166 337 585 466 524
1944 637 170 125 41 33 37 38 163 488 448 3Sl6 291
1945 489 151 99 19 15 25 36 209 361 502 357 424
1946 644 55 28 13 15 20 30 255 414 403 457 316
1947 258 141 36 23 19 53 48 212 409 403 330 525
1Q48 291 100 77 44 20 19 25 243 466 461 372 530
1949 208 134 48 35 16 21 37 207 310 410 421 379
1950 224 361 76 10 10 15 25 122 323 436 339 413
1951 110 38 22 17 15 19 33 160 411 489 291 311
1952 114 46 35 12 13 18 42 161 302 511 426 480
1953 515 167 45 20 22 17 29 227 428 44() 45() 376
1954 402 51 51 25 89 21 20 108 31 /~ 384 271 389
1955 184 178 120 33 18 21 24 93 267 506 518 359
1956 126 77 22 9 10 15 25 185 226 497 621 27'13
1957 142 163 115 48 15 13 29 177 342 392 354 444
1958 241 169 44 84 23 18 42 216 490 474 442 216
1959 320 93 52 25 23 21 32 156 404 606 396 240
1960 231 101 71 34 18 25 41 177 361 511 434 422
1961 355 125 99 52 41 33 52 194 473 691 684 301
1962 428 74 23 79 26 31 29 101 340 431 367 480
1963 243 152 101 59 70 36 35 138 306 454 330 543
1964 321 45 76 50 35 24 43 104 458 598 375 198
1965 292 100 72 102 39 41 34 78 279 413 386 242
1966 409 55 42 17 15 23 38 135 341 446 475 483
1967 301 83 22 17 18 17 20 137 566 410 495 585
1968 153 135 45 20 44 68 34 159 259 431 291 565
1969 154 64 35 7 8 20 34 186 573 558 466 361
1970 224 17 88 22 54 33 38 186 995 452 457 466 . ,
Month
Average 295 118 61 35 27 26 37 159 371 464 444 390
2'+1 1('/ ::'~ "')
, "
; ~ .
Annual I
Average 202
FIGURE 5
CONTOUR iNTERVAl 100 FEET
~ ... JtI <: "u,. sa LEVEl
D(P""H CuMS 1'\ • !.:--:::.-.'" " "'" J wEAN lOW[q lOW .rER
~cI!IIt( """""" "f~..: .. '., .•. t: ~#"'V.[ _IN( Of 1II{M,q.!.u'Ot
fH( Al'(JWGlIIIIIw::.[ 'J ~(I( 5 ~_U£HUFUl
0
" ( >
" 0
-0
~
LEGEND
Snow Course
Proposed Snow Pillow
Stream Gaging Station
Climatologi.cal Station
Permanent Snow Fields and Glaciers
Notes:
1. Drainage area at lake outlet -
11.4 square miles.
2. 28% of drainage area is covered
with permanent snow fields and
glaciers.
Snettisham Project, Alaska
First Stage Development
TOPOGRAPHIC FEATURES
Crater Lake
R.L.M. Mar 73
DESIGN MEMORANDUM NO. 23 FIGURE 8
CORPS OF ENGINEERS
MONTH
",,"UAItf
HBRUA"Y
WARCH
AP"IL
WAY
"UHf
.JULy
AUGUST
UPTUIBER
OCTOBER
NOVEWIER
DEI:£WII["
LINEA" REGRESS!QN EQUATION
L.OG Of'CRMrER CREEK flOW,. CFS·A+BILOG OF LONG RIYER Flow IN CfSl
CRATt". -0.145 + 1.21 Z (LONG)
CRATtR. -0.4e4 + 0.t'9 Q.ONG)
CRATtR. -0.290 + 0.906 (LONG)
CRATtR. +0.' 7 I + 0.' U (LONG)
CRATER.-!.III + I.Z85tLONG)
CRATtR. -1.442 + 1.31' (LOHG)
CRATtR. ~.77' + I. 154 G..OHG)
CRATER" ~"14 + 1.011 (LONG)
CRATER. -0.'35 + 1.090 (LONG)
CRATER. -O.'S' + I. 170 (LONG)
CRATtR. -0.567 + 1.054(LONGI
CRATt". ~.z10 + 0."4(LONG)
~ .00f--------+--------------~----_+----~~------~.~~
'" ..J
~ .,=-",0
STANDARD ERROR OF ESTIMATE
-itT
.122
.100
.07'
.0.5
.134
. 021
.04'
.043
.033
. 057
.065
CORRELATION COEFFICIENT =:tr ...
.• 0
.• 5
.'4
.11 ...
.7'
.• 7
.'7 ... ...
U.S. ARMY
), (
)
" , ,
)
u'" 500, -------~----_,------~------_,~----~.~,~~?~~~--~------74----~~----~~------~------~~------~------l ~~ , JIlTE:
~ffi ~ I ~ 40
~
lII:
'" I~
k U
S~
C
k
U
-' ...
/'
° zoo 400 .00 100 1000 1200 1400 1100
AVEUGE MONTHLY FLOW IN C FS
LONG RIVER AT GAGING STATION
1800 2000 2200 2400 2600
1. Correlations are based on about 13 years
of 51 .... 1 taneous records. Procedur~ used in
the regression analyses are those derived for
stAtistiCAl evaluations.
Z. This figure reproduced fn. Design
MeDora~ No. I, Exhibit 15.
SMETTISHAM PROJECT, ALA.IICA
""ST STIIG! O£VI!LQPlfttlT
CRATER CREEK -LONG RIVER
CORRELATION DATA
U. S. A"1IfY ENGINEER DISTRICT, ALASKA
fl\.ANNIHG AND R!~RTS '''AMeH
"ft"A"ED BY e,G,Q, DAT[ SEPT. '"1
DESIGN MEMORANDUM NO. 23 FIGURE 9
CORPS OF ENGINEERS
1300
-
IZOO
liDO
loao -
'" 90 0,"
>
0 .,
'" .... e-OJ
OJ ..
~
80 0 z
~ ....
'" >
OJ
-'
'"
70
0
1
/
60 0
AREA IN 100 ACRES
5 • , 2 I
I
I
I
i
I
! V / I
I
~: ~ // y ~ S~O . T> V
ELEVATION 1022 ! ~ MAXIMUM POWER PO L --7
NATURAL LAKE SURF C E
/I
0
I \1 g
N
I
/ \ I
/1 \",
-+ r---
/ ,
I
I
I ,
i I
I
I I I I I
50 100 150 200 250 '00
STORAGE IN 1,000 ACRE-FEET
AREA STORAGE FOR CRATER LAKE
I I '00 -'
:I
-~6
0 ., .
>-
I 200 '" '" .. ..
0
'" -o.
z
'" '" :0
0
I 100 ...i r
>-ori ~ Ji
z
-'" ~2 > 0 >-
'" '" e >
'" >--'
I 000 '" '" "' ..
!!
-a
~ .... e >
tOO"' ..J
"'
-
000
-
7 00
-
600
''''
U. S. ARMY
DRAINAGE AREA IN PERCENT OF TOTAL, ".2~ SQUARE MILES
100 90 80 70 60 50 40 30 20 10
10
DRAINAGE AREA IN SQUARE MILES ABOVE A GIVEN ELEVATION
AREA ELEVATION CURVE ABOVE CRATER LAKE OUTLET
I------------~:-:---------
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
~=------1 AREA STORAGE AREA ELEV, CURVES
1'010?=,
._-_ ... __ ._---'----------------------------------------------~:.;=.=.::::=:....,...::....:'I----=-~--------'
10
+12
~Highest Expected
I
Tide, Elevation 11.4 Feet Notes:
+10 l. Curve shows minimum tai1water -
elevations at powerhouse with no
backwater effects from ocean tides.
2. Tai1water elevation should be
taken from curve or from elevation
+8 of tide, whichever is higher •• -
;r;
;...J 3. Sill elevation -5.5 feet.
~
Q
f-o
(.J +6 t&l
~ p., ..
f-o
~Mlnlmum Power Output 300 c.Ls. ±
t&l
t&l
~
z +4
H
Z
0
H
~ > t&l
...J
t&l +2 ~
t&l
~
3: ...J
H -< E-<
0
-2
Tai1water at initial startup, assuming no degradation or aggradation in channel • ~ -~---------~ -----------------------
... -.....
~~ ~--
",--'"
~ Minimum tai1water assuming critical depth at sill. ~-~ I I I I I -4
o 100 200 300 4qO 300 600 700 800 900 1000 1100 1200 1300 1400 1500
DISCHARGE IN CFS
TAILWATER ELEVATIONS
FIGURE II
M <'
O·
1"-o
, )
7
0':
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"r~--'--r,l '-: r 1 I' !. I r 'T-._-'.~_r~
!=c~,r; ~:t> , " r' !: : i ' . r:~ -I ---. r+~ -c c ~ . ,!. I I r': I . I ' I + r i '-: 1 -I 1" -T ;"",; • --I -'.I' I +_,. __ ;. ~;HU_~~---_fr~:~ ~r; ; +t ~:~~i~:_-jJ: -r :-. ~i' ~~J-: ~J
rI:
:1' . .~.
I ,
-:~
J
CORPS OF ENGINEERS
8 9 .'00°1 t t
8500
8000
7500
7000
6500
(f)
0::
<r
..J 6000 ..J
0
0
~ 5500
0
0
<::l
x 5000
(f)
~
(f)
0 4500 u
4000
3500
3000
2500
2000
1500
1000
500
O~
8 9
EQUIVALENT DIAMETER
UNLINED POWER TUNNEL
10
t
RAIL EXCAVATION
EQUIPMENT
10
II
II
.,UIVALENT
Ur-LINED POv,
12
12
'~ET
TUN'·"
13 14
! 3 J?
RUBBER " .... U,'/ATION
f MENT
CRATER LAKr
UNLINED POWER TU ,NEL
COST VS
EQUIVALENT DIAMETER
(f)
0::
<r
..J
..J
0
0
z
0
0
0
x
(f)
~
(f)
0 u
PENSTOCK DIAMETER IN FEET
4.5 5.0 5.5 6.0 6.5 7.0
I! , I
$ 9500f
90001
TOTAL COST
8500
8000
7500
MOST ECONOMICAL DIAMETER
7000
6500
I
6000
5500
5000
4500
4000
3500
3000
2.500
VALUE OF HEADLOSS
2.000
1500
1000
500
0 t t t
4.5 5.0 5.5 6.0 6.5 7.0
PENSTOCK DIAMETER IN FEET
7.5 8.0
/
7.5 8.0
U. S. ARMY
CRATER LAKE
STEEL PENSTOCK
VS
COST
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
DESIGN MEMORANDUM NO. 23 FIGURE 15
CORPS Of ENGINEERS
]000
980
r
~
~ i
950.
Q
~
~
~
~
~
~
= =
~
c-
~
=
i\8~
850 I
I
780· I
!
76n ! ;
740 .
10 12 14 It 22 24
I,
~I
26 34 36 38 40 42 46 48 50
TUMBI.E OYTPUT -1000 HP
U, S, ARMY
HOff
1. TU~BrNE cHARACTERISTlrS ":OVIDED BY HYDRO -EL[CTRIC Dl3IGN BRANCH
2, NEr TURBINE YEADS BASED 0, 10' PIlWER TU.NNEL AND 6' P[IETOCK,
55 58 60
U.S. ARMY ENGINEER DISTRICT, ALASKA
CORPS Of' ENGINE EM
SNETTISHAM PROJECT, ALASKA
fiRST STAGE DEVELOPMENT, CRATER LAKE
TURBINE OUTPUT
DESIGN MEMORANDUM NO. 23 FIGURE 17
STORAGE
TOTAL 121,000 A.F.
DEAD 36,430 A.F.
USABLE 84 570 A F l
~-
WATER
YEAR NATURAL AND
MONTH
CFS CFS
1919
JUL
AUG
SEP
OCT 209
NOV 67
DEC 45
1920
JAN 100
FEB 35 LEAP YR.
MAR 16
APR 20
MAY 53
JUN 177
JUL 406
AUG 532
SEP 262
OCT 140 , .' ,
NOV 92
DEC 25 ---f------
1921
JAN 24
FEB 31
EAR 24
APR 34
MAY 138
JUN 305
JUL 399
AUG 360
SEP 297
OCT 290
NOV 75
DEC 95
1922
JAN 34
FEB 10
MAR 10
APR 35
MAY 145
JUN 297
JUL 437
AUG 471
SEP 352
OCT 202
NOV 158
DEC 41
1923
JAN
I
2l
FEB 28
MAR 38
APR 47
MAY 160
JUN 297
JUL 452
AUG 483
SEP 502
OCT 230
NOV 198
DEC 77
1924
JAN 28
FEB 17 LEAP YR.
MAR 30
APR 39
HAY 229
JUN 400
JUL 584
AUG 566
SEP 581
POWER -STORAGE TABULATION FOR CRATER LAKE
DATE MAR 7l 1973
CAPACITY 27 0/31 0 MW COMP BY RGL -
RELEASED REGU---RESERVOIR
._------STORAGE ELEV. POWER PLANT STOR-FLOW LATED "K" REMARKS
AGE FLOW END OF AVER- AVER-OUTPUT CAPABIL.
MONTH AGE AGE -------
1000 AF CFS CFS 1000 AF 1000 AF FT. MW MW
-
I
0 0 209 121. 0 121.0 1022 72.2 15.1 31.0 FULL
-5.75 96.65 I 163.65 115.25 118.1 71. 8 11. 75 START CRIT. PD
-7.47 ....l.21. ~2+-166. 43 107.78 111.5 70.6 11.75
-4.23 68.82 168.82 103.55 105.7 69.6 11. 75
-7.86 136.66 171.66 95.69 99.6 68.45 11.75
-9.83 159.9 175.9 85.86 90.8 66.8 11. 75
-9.58 161.05 181.05 76.28 81.07 64.9 11.75
-8.20 133.36 186.36 68.08 72.2 63.05 11. 75
-0.75 12.52 189.52 67.33 67.7 62.0 11. 75
+13.58 -220.91 185.19 80.91 74.1 63.45 11. 75
+21.93 -356.62 175.38 102.84 91. 9 67.0 11.75
+5.54 -93.18 168.82 108.38 105.6 69.6 11. 75
-1. 73 28.1 168.1 106.65 107.5 69.9 11. 75
-4.6 77.31 169.31,102.05 104.4 69.4 11.75
-9.07 147.5i -::: :~-t!:: ::-97.5 68.1 11. 75
-9.42 153.23 88.3 66.3 11.75
-8.39 151.17 182.17 75.17 79. {~ 64.5 11.75
-10.07 163.7 187.7 65.10 70.1 62.6 11. 75
-9.58 161. 03 195.03 55.52 60.3 60.25 11. 75
-3.87 62.86 200.86 51. 65 53.6 58.5 11.75
+6.26 -105.17 199.83 57.91 54.8 58.8 11. 75
+12.74 -207.16 191. 84 70.66 64.3 61. 25 11. 75
+10.83 -176.12 183.88 81. 48 76.1 63.9 11. 75
+7.03 -118.15 178.85 88.51 85.0 65.7 11.75
+7.06 -114.75 175.25 95.57 92.0 67.05 11.75
-5.95 99.98 174.98 89.62 92.6 67.15 11. 75
-5.09 82.76 177 .76 84.53 87.1 66.1 11. 75
-9.1 147.75 181. 75 75.43 80.0 64.65 11. 75
-9.85 177.4 187.4 65.58 70.5 62.7 11. 75
-11. 39 185.19 195.19 54.19 59.9 60.5 11. 75
-10.12 170.06 205.06 44.07 49.1 57.3 11. 75
-4.14 67.29 2l2.29 39.93 42.0 55.35 11. 75
+5.06 -85.10 211. 90 44.99 42.5 55.45 11. 75
+14.44 -234.76 202.24 59.43 52.2 58.1 11. 75
+17.34 -281.9!~ 189.06 76.77 63.1 62.15 11.15
+10.19 -171.22 180.77 86.96 81. 9 65.0 11.75
+1.51 -24.51 177.49 88.47 87.7 66.2 11. 75 I
-1.16 19.5 177 .5 87.31 87.9 66.2 11. 75
-8.55 .....l39.08 180.08 78.76 83.0 65.25 11. 75
-10.12 164.48 185.48 68.64 73.7 63.35 11. 75
-9.10 164.0 192.0 59.54 64.1 61. 2 11. 75 I
-9.95 161.83 199.83 I 49.59 54.6 /58.8 11. 75
-9.67 162.45 209.45 39.92 44.8 56.1 11. 75 MIN. POOL
-3.49 56.79 216.79136.43 38.2 825 I 54.2 11.75 END CRIT. PD
+4.84 -81.4 2l5.6 41.27 38.9 54.5 11. 75
+15.16 -246.5 205.5 56.43 48.85 57.2 11. 755
+17.95 -291. 9 191.1 74.38 65.4 61.5 11. 753
+19.19 -322.5 179.5 93.57 84.0 65.5 11. 757
+3.47 -56.4 173.6 97.04 95.3 67.7 11. 753
+1.52 -25.5 172.5 98.56 97.8 68.15 11. 756
-5.94 96.6 173.6 92.62 95.6 67.7 11.753 ---
-9.19 149.5 177 .5 83.43 88.0 66.3 11. 768
-9.52 165.5 182.5 73.91 78.7 64.4 11.753
-9.75 158.5 188.5 64.16 69.0 62.35 11. 753
-9.37 157.5 196.5 54.79 59.5 60.05 11. 78
+1. 78 -29 200 56.57 55.7 59.0 11.80
+12.26 -206 194 68.83 62.7 60.85 11.80
+24.54 -399 185 93.37 81.1 64.9 12.01
+24.05 -391 175 117.42 105.4 69.6 12.18
+3.58 -60.17 520.83 121.0 119.2 1018 72.0 31.0 FULL-SPILL 6 5M
FIGURE 18
..... 11 .. N .... ~
I--• .Li. I -WL.1..i. I -~ I -... ~ I _ .. ....l.O-.... _ ... --+-+-. I --• ....Lli...-I--.~
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I 1 ! '_ !
, , '! ~
InF:~Tr,N MRMORANnTTM
PLAN OF DEVELOPMENT DM #23 II'
POWERHOUSE DESIGN REPORT DM x2.ll
...sJll'TI,EMENT TO DH if23
,
I
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1
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1-----------------------------++-t-i"-t--+-+++-+-~-~ -~-~t-~ -+t-t--t-t-+---+-t-+-H--+-+-+-+-t-+-t-+-t-++-+--t-+-t--lf-++-tt-+-t-+-t-lH
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t-----------------------------------------------~-t -1+ l -rr i -11-+ 1-+ t--:-it ---------+ ~~_-ttt--J+, --+t~T-t-Ti-+, -lj Tt -I l~ 1+-t-r-l-+~l-1 ~l-T ;t-:-++-I I , ------------------.. ·-:~:Tlltf1~·n-rlq±i.tr1TI I ~ r·· :t~ d 1+ +1 ~ I:;!':' ttt-l=:--~i:l~-~ TIj-=Ti+t+r--J+-t-'-++-t---rH ~------------r -, -t +i + ! ~ I t-ttt-1 _ }-+-+-_ _ t-'-m-tj j-~i -t-:-++-+ _-i-+~'-l~t--t ~ t_J-~-"~ -;}11: 1 ~-------------=~-=--===-~-=~~-==-------r-t, -tt~, ---~--~}-:~l++i=~r-~-~ --t~=t-t~t-+ -+l+f-t+-r~ -T-t-H-~--t=t-~-1-1 t-Ll' 1 ~ +_-1+-;:--it-~t-t-++-++-+-+-1-+_~-t
r--------------------------------. r 4JEitL>#t rrtt I ,t r· Ht ~++fJt:1 -Hill!· +r++-II rrrTf-Tr -+-+-+-t-+-+-t-+-1--~~·-===~-=~---=:~=-=-::-::----ilft nJ1+Ttt Ht+~~ll I ~ t+il-r-r-+-jtt-ttl-+~-H~m~~ ~~r~t= -tm' 1 I---t-_t"++-t-+-T-t~
t------------------------.. -----------' t--ft'---L t--++Y~-H--d-t--i-t--------'-+~ i+H-t-H -H-~ +#-++ 1"-1----++ +-++ t-H-II I -=~=--===--:--------=-~~~-=~--.. =~=rtt~r+t~+-t-l '-t+~: iiJ
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_ -tn~ -' --t-=:_:= -~ r~~ lit --tt-t"!-;--~-t-l~~~+=-r~rfJ i -tt t-~~~H--l+-~ : }-+--t-+-H r---------------------------------------------~ f--'+I-' t---++++'-~t---t--t-' ----1--f -+ , ,--t-.-'-+-t ±+-t--l-~-----r-
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f --f-H-i---i+ -~--4--+-+rr H ++-~ T r--+tt-r--+-+-~r --I-, 1 l' tJ :t ----t-itt-,-+ -+-, -+ i---t -t-r-~-t-+-+ r d-' --~+t:t--r-! -t-r ~~t-1-+ ~~ ___ -==~-=-------::-~=-~~-.-f-t $1!:=:r f I.±-'=a.tttff+~~t· .. F~_ n,-L-Tt~ i ~·ft--~'-n=8-tf~--:-
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t-------------------------------t-t-+-t F--t + -r-----t-ti-: -+ I I: -t-1>4--H-+-++-+-t-+-+-jf-++-t-+-t-++-'H
-------r-t-~-+ F-t-! --t-i± ! t-t-+-+-+-+-+--+-t--lf-t-+-+-+-t-++-~ ~=======~_-=========::::===--~-----------1 +---;+----+1----~H-i-tt-'+--j--t-~ -Il.r ---I--! 1 H-f--+-+-+-+-+-+-1"-t--t-f1-+-t-+-t-1
DESIGN MEl-'~~=REVIEhT & APPR~~RTISE & AWARD r-IN STALLA rIor; OR CONSTRUCTION
~.z1 _ ~/,/ ____
LPLANS & SPECS ~OP TIME OR MOBILIZATION AND PREPAMTORY WORK
NM For .. 104 Dec 65
DESIGN 8 CONSTRUCTION
SCHEDULE
CRATER LAKE PHASE
Rev -Oct 73
FIGURE 19
CORPS OF ENG IN EERS
'.-10
ADM R A
s L A N
/
IS' <
1 -t-
41t
()
+
L T Y
o
JUNEAU SUBSTATION
(EXISTINGI
pAS S A G
WEST TER,
(EXISTINGi
./
SUBMARINE C~
CROSSING
(EXISTINGI
£
'"
SCAL( IN .. ILCS
VICINITY MAP
.~
-
+ LAKE ) t~
~~ ~ , V
Cl
C0
0[;$:
EAST TERMINAL (EXISTING)
+
-<:)
"V +
U'
U'
, . = .~
"\7
LONG LAKE POWE~ TUNNEL~
(EXISTING) I
CRATER LAKE POWER TUNNEL ,
\
13UV OVERHEAD ---------------,
TRANSMISSION LINE
(EXISTINGI
Q
«'
U. S. ARMY
LOCATION MAP
NOTES
ELEVATIONS OF TIDE PLANES AT SPEEL RIVER REFERRED TO ~EA~ lOI/EIl LO" "ATER
AND PROJECT DATUM ARE AS FOLLO\llS
HIGHEST TIDE ([ST)
~EAN HIGHER HIGH WATER
MEAN HIGH \t/ATER
HALF TIDE LEVEL
MEAN LO\ll \t/ATER
MEAN LOwER LOlli
LD\IIEST TIDE
MLLIiI
22 5
:59
IIL8
B' 15
0.0
-5.7
PROJECT DATU~
II,ij
4 B
3.7
., 9
95
·11 I
-15.B
TIDAL DATUM PLANES ARE BASED ON 7 ~ONTIiS {' 65 TO 8 65) OF AlITOt.1ATIC GAGE
OPERATION BY USGS
ALL ELEIJAllONS ARE IN fEET" REFER TO PROJECT DATU~.
+
POWERHOUSE (EXISTING)
U.S. ARMY ENGINEER DISTRICT. ALASKA
~ ... ~ I[HQINEI[M
~-"'''_1lA
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
LOCATION AND VICINITY MAP
Fill ""I,n ...
S1, 1~'3
I-SNE -96-01-01-0711
.... co
NO. 23 PLATE I
CORPS OF ENGINEERS
)
/
CRATEr'? L ;"r<[
...... 5.' [II ~ i,C12
J
?
\
\
GATE STRUCTURE
J>( \ \
~
CRATER LAKE >.~" r POWER TUNNEL
~~
Q
I-EX/Sr"IG
, TFrA/o,:v,"/SS/ON L I/vE
X , \
(
1
\
:7 y'
/
o-.oJ
CONTRA<::TOR
CAMP
\
\
MOUNT AiN
BORROW AREA ~m 2./
l"'II'tIP"'OuSE
0-WATER TANK
~PROPOSED
SEWAGE LAGOON
(
?
BOO
_1400
DESIGN MEMORANDUM NO. 23
/
U. S. ARMY
U,",SL.'Rv(YED
/
1600
----------»-----.~--I
J ___ ~;----J
------------+---
--~-->-~-----j->-
U.S ARMY ENGINEER DISTRICT. ALASKA
!.lBI6HB>: ;::-~ ~
"",~,--
ChlCKW----
.' -,--+--C.::ly
"-Ef'AII:Q.I,
CORPS OF ENG'NEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
PROJECT GENERAL PLAN
PLATE 2
CORPS OF ENGINEERS
CRATER
LAKE
",,' ? 00
GRAPHIC SCAl'! --.!.f' [ ['. 100" o·
u "'," ,
5, ARMY ENGINEER ",~:c-__ ,-----__ COR ,PS OF EN~i~TRICT, ALASKA
,_ ,"ceo"W AC .. ::
R5
SNETTISHAM P FIRST STAGE DEVEL~OJECT, ALASKA PMENT, CRATER LAKE
GEOLOGIC MAP
~~~ __ LAKE AREA
PlATE 3
CORPS OF ENGINEERS
)
-----;_./
~---~
'\
~---"
~'-:-'~!_~Oo .. /
,<
'. ~ -----------
'.cC~H I ATEDi
100 o· ICO' 200'
IIJ •• ..,.ID • .".ol_....;,;====:::J
G"",PKIC SC. ... L [. :". 100' -o·
CHECKED
U.S. ARMY ENGINEER DISTRICT, ALASKA
CORPS OF ENGINEERS
U. S. ARMY
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
GEOLOGIC MAP
GGREELt:y
REF"
.L
PlATE 4
CORPS OF ENGINEERS
'" :J
!;;
C
I-
U ... ,
o a: a.
z o
I-... > ...
--' ...
1400
1350
1300
1250
1200
1150
1100
1050
1000
950
900
850
800
750
700
A
/
I
\
f ~ !
A
\
\ I: I
\
Ii +.
SURFACE CRATER lAKE 1020' ~
TO 310'
QUARTZ DIORITE
),/\ "
\ I
DH 98 I
DH 100 I
10+00
QUARTZ DIORITE
L MAXIMUM OPERATING PRESSURE
HEAD (INCLUDING SURGE)
----------
TO 334'
PLAN
100' o· 100' 200'
...... ! ! I
(HIAPHIC SCALE' ,". 100' -0·
QUARTZ DIORITE
jMINIMUM OPERATING PRESSURE HEAD
---___ L ________ _
POWER TUNNEL 0.005 SLOPE
DH 101
SUPERIMP05ED \
'~"4 : \~~:\'~R'~W'~~?"
I
BROKEN,
jAL!fR[O
SOFT
IGRANO-I DIORITE
" 1 DIORIT~
I
TZ +: HEAVILY ALTERE GRANODIORITE __
DIOf!I~RANDDIORITE
TD 232
\
15+00 20+00 25+00 30+00
PROFILE
~. 0 ~.
1000.l1li
ClRAPHIC 'CAL[' I'· 'o'-O·
VERTICAL
'00' ,
~.~'~KK~f .... .t!O='==~2r'
GI""PHIC SCALE, ,". 100' -O·
HORIZONTAL
GEOLOGIC LEGEND
QUARTZ DIORITE
FRACTURE (PLAN) WITH DIP DASHED
WHERE LOCATION IS APPROXIMATE
FRACTURE (SECTION) SHOWING
APPARENT DIP
DRILL HOLE
U. S. ARMY
QUARTZ DIORITE
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
POWER TUNNEL GEOLOGY
.L.
DESIGN MEMORANDUM NO. 23 PLATE 5
CORPS Of ENGINEERS
" :0
t--
<t
"
t--
U
W
~ a:
Q.
t--
W
W ...
z
" t--
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W
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I \ i--______ _ ___
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1100
,'"
1050 ---
A
1000
9~0
QUA'lTZ 010" TE
900
B~O
BOO
750
700
650 '-----+_ ~. +---. ,---1--
40+00
GAAf'hl' " A' f ,". 100' (
-------
QUARTZ [
TLINGIT FAULT-:'=-:::::';~
/
MAXIMUM OPERATING PRESSURE HEAD
(INCLUDING SURGE)
/
lr
___ ---L-____ _
III -------+rl
------\----III III
1'1
II
II
II
I I
I I
QUARTZ QIORITE
rMINIMUM OPERATING PRESSURE HEAD
/
------~----------
-.--------------------------
,
il':
I I
-________ 1 I
------------------c'> ----I
I
DH 99
QuARTZ
DIORITE
HIGH ANGLE
JOINTS
TO 350'
I
. ' ;'
1150
1100
A'
1050
1000
9~0
900
B~O
BOO
750
U. S. ARMY
---+-----+--
4'3 +;}) . +--.: ·-------I---I------+-----·-+----+----j'----+I ---t---+----+----j---6-:-0++-:-00--+----f---t---+--'--::6:5~+:00;:--+-~=:=:~:::c.:=========~".:.:.:.:=:========::::::~ 50+0n 55+00 ~
~':JFI LE
,>, !lO' 100'
II£::-=-==:::10'_ .....
G""PHIC ~ "L(, ,',50 -0'
,~ ",T I CAL
laO 0
~ .... '
100 200 , ===:::J
G""PI-lIC 'leA t ,". 100'-0·
,.(. ' NTAL
!.JCC·'Il:)
E wAffLE
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
"NCHO""GIE A~ASI<'"
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
'-------------.... -. ._,,-.. _-_._-------------
DESIGN MEMORANDUM NO. 23 PLATE 6
CORPS OF ENGINEERS
1300
1200
1100
1000
900
800
~ 700
n.
~ 600
'" "-
~ 500
z a
f-« 400
>
'" --'
'" 300
200
100
a
-----
,-CH 9<:<
I SUPERIMPIJSED
QJAR'Z DIOFlITf
-----+---
100' ~ ____________ "",,,,"1_~':;,:,OO ~:r'
GRAPHIC SCALE ;". 100'-0'
-----------
I
70+00
'\ -----------------~
-MAX 1<1'" l I p~ SSU",F
-8 v'OINTS AVG (\ P &')0
I
75+00
'> '-
\
r---. ------\
U. S.ARMY
DESIGN MEMO I" 96-06-19-02/5
RANDUM NO. 23 PLATE 7
CORPS OF ENGINEERS
1400
1350
1300
1250
1200
1150
1100
1050
~ 1000
": 950
900
850
800
750
700
TRASH R ~CK --
ROCK TP'
~--""---------t----_.------+-
5+00 10+[
1!..NLi,~L _ POWER TUNr-.:"'~
MI~~I.UM ROCK COvt.r,
--+--------+---
20+00 25+00
400'
~oa~Dd=d=====~'c===~1
GRAPHIC SCALE' I" -200'-0·
200' o·
30+00 35+00
PROFILE
'00' 0 100' 200' ~~~===±I====~I
GRAPHIC SCALE 1".100'-0·
VERTICA.L
GRAPHIC SCALE' 1'·200'-0·
HORIZONTAL
U. S. ARMY
PROFILE
1150
~,'I:: II 1100
:,1
'I' 1050
TANK ----11 SURC·~ " ,'I u 1000 I-
"
0 ...
II I-~ <n II ~ 950 II !
II "-900 z
'I
0 0
I-;:: I, 0: BSO «
'II ., >
'"
I-... <n ..J I, BOO ...
" SLOPE O.OO~ I,
750
R8:K TRAP 700
40+00 45+00 50+00 55+00 60+00 65+00
U. S AH\.1Y ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
DESIGN MEMORANDUM NO, 23 PLATE 8
CORPS OF ENGINEERS
DESIGN LINE
TYPICAL UNLINED SECTION
SCALE 1/2" ~ 1'-0"
/ : ''-BLOCKING I
/ AS REQUIRED
LGROUTED ROCK BOLTS
I EACH SIDE OF WEB (TYP.)
(DESIGN LINE
,-STEEL SETS
/
/BLOCKING AND WEDGING
\~ STEEL STRUTS
AS REQUIRED
MODERATE SET SI 'F'QRTED
TYPICAL CONCRETE LINED SECTION
SCALE 1/2"" 1'-011
" L..AGGING AS REQUIRED
HEAVY SET SUPPORTED
BLOCKING AND WEDGING OR
DRY PACKING AS REQUIRED
_____________ "-FULL CIRCLE STEEL SETS
1+----0£ S I G N LI N E
TYPI CAL SET SUPPORTED SECTIONS
SCALE: liZ"" 11-a"
2' 0' 2' 4' .
........ -~RAPHIC SCALE 1/2::=" ,=,::=, ."0·" _ ..... 6
i)
U. S. ARMY
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
RECOMMENDED POWER TUNNEL
DETAI LS ~
DESIGN MEMORANDUM NO. 23 PLATE 9
CORPS OF ENGINEERS
'-i-ir
Li-l
I
61 +60
\ ----;-r
61 +')0
,.--DESIGN LI N~
/
J
I. I !;l ~_ -0 __ _----->-I
UNLINED
TYPICAL ROCK TRAP SECTIONS
NJT n SCALE
! /-SURGE TANK
M ~ORIF'CE ~ rROCKTRAP
I
b3.J. 55
PLAN
SCALE 1"-20'
/SURGE.TA" 'R,FT -TRASH RACI(
---::-
-¥'-----
____ t. ELEV. 758.5
_/ ~ L I J'Z'
-----,--------,-~ -2-0----1i----[-,-5.-0 .. ---,·-,-].-------1
1
63155
-DESIGN LI N[
,
I ~' -0' ---J
CONCRETE LINED
t
I
(~4i 05
PROFILE
')CALE 1"-20'
ROOTI1AP~
'-
65+4D
SURGE TANK COVER ---
AIR FLOW-~
~. / )'J
~.------=-11. ~":. _ )a'.i' .1.-____ • .::.'
--.fI,
SECTION A
NOT TO SCALE 10
4-
DESIGNED
.Il) 8 JCG
DRAWN·
CHECK~O:
JCG
~REPARED:
U. S. ARMY
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
RECOMMENDED POWER TUNNEL
WRGE TANK
NU~'U.
1-SNE -96 -06 -19 -0218
OF
DESIGN MEMORANDUM NO. 23 PLATE )0
CORPS OF ENGINEERS
POWER TUNNEL
/ ROCK TRAP
F
65+00 66+00
I 1/2
BEGIN STEEL LINER
SECTION
SCALE I" = 20'
67+00
A
9
68+00
PROFIL~
SCALE' I"· 50 -0
STA6S+6S~~68+00 --=_= 67+00 66+00 69+00 72+00 70+00 711-00 73+00 74+00
THICKNESS PROFILE PLATE
900
800
lOa
600
'00
400
300
200
76+00 77+00 78+QO
O"(""'()~
DISTRICT. ALASKA U.S, ARMY ENGIN~;~GINEER5
U. S. ARMY
COR:::~~O"'o. 'c,"" ALASKA
ETTISHAM PROJECT'CRATER LAKE SN E DEVELOPMENT,
FIRST STAG PENSTOCK
RECOMMENDED",
PLATE II
CORPS OF ENGINEERS
1---
I
48"0"
PLAN AT GATE ROOM FLOOR
SCALE 1/4"· 1'-0·
J_J
VENT
/-HATCH
t--~ --+--+----~----,------,,_.
GATE LEAF
6' X 12'
I·
.L.' ~--
1\"
--.. --~
!
-~l'
I
\
.._.--._-------_._--~
'T --.
-.---.-~--.. ------~---:--
----~---.-------
SECTIO N
SCALE 1/4' '" ;'_0"
I Co
, i
·i tl
~ ..
~---::"-----------
1
U. S. ARMY
15'-0· -1
~~ I I,
!I l ~
I CT--LI
p-"
'" I .... ~
SECTION @
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
DE;IGNEO
<} /< SNETTI SHAM PROJECT, ALASKA
FIRST STAGE DEVELOp~Er\H, CRATER LAKE
CHEO::ro
j (~-co' RECOMMENDED POWER TUNNEL
DESIGN MEM6RANDUM NO. 23 PLATE 12
CORPS OF ENGINEERS
1400
1350
1300
1250
1200
1150
1100
GATE STRUC;URE
1050 SLOPE OOOO!
~ CRATER LAKE ELEV. 1020!
i:' 1000
" 950
z
<e 900
>-<[
~ 850
"' 800 TRASH RACK
750
700
ELEV 1040
ROCK TRAP
5+00 10+00 15+00
~, c:ll
"I ~I . ~I 0.6, STATIC HEA~f
I ~ I ~J I, STAJ"IC HEAIl--1
. ~ 1.5 , DYNAMIC HEAD .-------i~
UNLI NED POWER TUNNEL
MINIMUM ROCK COVER
"""
0
!;;
20+00
U. S. ARMY
g' ~ g § g & 0 ~
g
12 12' (to ~ o. 0; 0; I!;
PLAN
200' O' 200' 400' IM-._. =::J
GRAPHIC SCALE' I'· 200' -0"
1150
ELEV 1080 1100
1050
SURGE TANK '" ~ u 1000 0 >-'" "-:s 950 '!; ..
"-900 z 0 0
>->= 0: 850 « « ~ to
800
/
POWER_TUNNE_L _
_ SLOPE 0.005 ============~~====.=-=-~-========================4~~ 750
25+00 30+00 35+00
PROFILE
100' 0 100' 200'
.~ ••••• ~.~ ...... C===~
GRAPHIC SCALE I", 100 -0·
VERTICAL
200' 0 200 400' --------. ===i
GRAPHIC SCALE' I"· 200'-0'
HORllONTAL
40+00 45+00 50+00 55+00
ROCK TRAP 700
60+00 65+00
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS 0 .. ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
RECOMMENDED POWER TUNNEL
ALTERNATIVE GATE STRUCTURE
PLAN 8. PR ILE
I-SNE -96 -06-19-021 II
RAN DUM NO. 23 PLATE 13
CORPS OF ENGINEERS
A
14
U. S.ARMY
1___ ------____ 2iL~ __ -----------'
I
PLAN
ELEVATION 10400'
S":AlE: I 8" . l' -0"
PLAN -GATE ROOM FLOOR
--t PiJ .... ER TlJ~~EI
BULKHEAD ALTERNATE
SCALE 3 32 1-0
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
..... CHOR ... "a:, "LA""'''
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
-!~:_ '/oJ1'--llAlE.:::: .. r:I~,I'!Il" :.cAlf
, ,~/ I~FSNEl~9U6~06-19-02/12
DESIGN MEMORANDUM NO. 23 PLATE 14
CORPS OF ENGINHRS U, 5, ARMY
PLAN ELEVATION 1040
SCAl.E. I a' t' "('\'
U,S, ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENG1NE:ERS
"~--'SNETTISHAM'PROJECT,ALASKA
hi1S;2---FIRST STAGE DEVELOPMENT, CRATER LAKE
LTERNATIVE U
PLATE 15
CORPS OF ENGINEERS
70 0"
11 I II I II I I I r II !I ; I ' II I.J" I II I II I III IJ
Q
@ V-HOIST
"00 0 ./
~~------------~--~ -C:;::H::::rr===Q-lF~~~ ELEV, 1040
BUU<HEADSLOT /'
.',
MAX WATER SURFACE
ELEY,IO~
r-~~~
t-."-.
\ ----~GAHGljtDE
I, I "R VENT
!
I
i I
, I II
I, 11\
r !T'C •••• ;~ L,'j I: ~\2.>~==--1'
~ ,/ I III ~-----------------'1 -<:::: .. -~~-: II ""-TCAC:'G~". ___ ~ .~
"t '~.~ CC •••••• __ ..j ~.:i~~.~ ~:. • . . :~'-=:::-..:..:.c..-~
TRACTOR GATE
~CAl !
TAINTER GATE 8 BULKHEAD
SCALE: I 8
U. S. ARMY
19' 0" .1 h-.-~-~ ~-=.--[ ... ''''ii 1-~-1 --~. 'II~J-----~. ,-~ ~-!d~. '-'-----
',", --'~ ... h~, , , . " ... '.' .J ROLLER TRm ~'-----.!'.i"
SECTION (7:;\
SCALE. lill" _ I'-O~ ~
U S ARMY ENGINEER DISTRICT. ALASKA
. . CORPS OF ENGINEERS
ANCH"""'G~ ... L ..... " ..
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
CHECKED,
JCC
RECOMMENDED POWER TUNNEL
GATE STRUCTURE A~ERNATIVE m
CORPS OF ENGINEERS
/ POv.'ER TU~~EL
(T~ ~ I. r"'~T
.i~l, ... ~!%vr-7 ~-~-
I -CONCRETE LIP
1
I~ --DEAD END ROCK TRAP
i IQ
;::
//
/ -----PO' .... ER rUNNEL
/
PLAN
seAL t I "~ 10'
SECTION A
SCAL[' 1"= 10' 17
v:OS JCG
"RAWN
CHECKED
JCG
NOTE
PLAN ~AY [JE ()PPOS I TE HAND.
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
ANCHOR ..... " "'L.A."'",
U. S. ARMY
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
POWER TUNNEL
ONE
I-SNE-96l~06~19 -021 15
0'
DESIGN MEMORANDUM NO. 23 PLATE 17
CORPS OF ENGINEERS
r-
L
~
SECTION
SCALE I" 5'
8
18
/
f (-
~ )
~1
/
t-
al
r--HID STAGf TAP --
/
TIo,'O STM,E TAP--
SECTION
5:'HE: I I;
A
18
,100 R
U, S, ARMY
NOH
PLAN ~AY [JE OPPOSITE HAND.
CORPS OF ENGINEERS
Itt ... 000
/
/
CRATER LAKE
j /
/
/,
GRAPHIC SCAl[ I", 100' -o·
U. S. ARMY
(
/j
---~-----...--/-
U.S. ARMY ENGINEER DISTRICT, ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FJRST STAGE DEVELOPMENT, CRATER LAKE
RECOMMENDED POWER TUNNEL
DESIGN MEMORANDUM NO. 23 PLATE 19
CORPS OF ENGINEERS
IO~O
'-----~
",
0' 100 200'
IDo 000",0[110::\0' _...t===::::J
C'AA,PHIC SCALE' I'. 100' -O·
-+
Cvv
U. S. ARMY
u.s. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
RECOMMENDED POWER TUNNEL
DESIGN MEMORANDUM NO. 23 PLATE 20
CORPS OF ENGINEERS
EXISTING
GROUND
,
"-ROAD
i ~1
I
!
I
.... 5'(TYPL 4'/ SELECT FILL)
LI "" T S OF I ~ / ~ I (/ !
CLEAR'NG-z. GUARORA'L~ :=---_.t~T __ LJif.* H ,1 __ 1
1,2L ~ ~r--.) -1 . '~l 1
j l~ ~ __ ~-'-_ "I' 6 + 6 .+ 4' .J
TYPICAL CUT SECTION
ACCESS ROAD
~lIM\TS L !5'(T_'(fL •. .r--"' OF CLEARING
i/ \
"
24 45f-' \ SUWe: '. . ~~' ' ANGL E
I ~ (~' J
EXISTI,..G ______ (~
GROUND ~ // ,I
'--/ i
~ ROAD i
1,'/ 1
LlhilTS / I
OF CLEARI"'G~ !S' IT'I"P) _I. t--~--..-l /~ ! SELECT ;
IJF FILL SLOPEs
I ! -I ,,/ ! FILL i
I
G:.JARDRA'L-l ~~ ...-/ / I. -{ ,..'FT I i 1FT ~. '4 ,I
Lrl,/ ....______---+----I -'-t~ _~ _~4_~.~41H"L---~'7 I .~ I ' I '",1 .j' /~/~., r------_6'_~ ~'____ ~ 4
24
TYPICAL CUT SECTION
DIVE RSION TUNNE l ROA D
__ 6_'
~ 4 l
,.
SCALE' ,", 4'
Ii. ROAD
I ,
~~M~~SEARJNG~
",5 CrY eL
:: 24
~)~
tifT iiFT /~' I
~~~cc_ ~~.:-==~~
,2' ;,ccrss/. f,/)AO
< 1
~I
,0 C,'v'ERSION TiJNNEL ROAD
~~L~lJ1-~UJillL
ALL R OA.D..S...
SCALE "·4'
\~ SLOPE
A~GLE
_.1. _
//
\-------
r~
I
I
I
I"-ROAD I
I DEPRESS I
£~=:-:::2t~~\j~~~
~;' ----~·A~ "DROP 'NLET
I ~-" "':'~ -~ I' MIN.OIA CMP, AT 400' WITH GRATING
! MAX_SPACiNG ALONG ROADS
TYPICAL CULVERT PROFILE
_ --CMP
t : T
+~
SECTION A A
SCALE: i".2'
~----CC~p
\----1----i----
BE D
TYPICAL STREAM ICULVERT PROFILE
SCAl E I ~ 4 ROAD SURFACE ~~~~OC: -~~~ :-
", F'LL~~ ;~'A~<//·
~---/--'" ,--'-----EXISTIt-lG STREAM
/ BED
(
~2' ~IN OIA. C:MP
S':t>.LE I": 4'
22 C/ E'O
.n
U. S. ARMY
NOTES
I FOR A SLOPE ANGLE OF 22° OR LESS,USE A
CUT"SFILL SECTION FOR ANGLES GREATER THAN
22°,USE CUT SECTION
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
Cii',G"C '--:,Co T-__ SNETTISHAM PROJECT, ALASKA
l.R;~1i'T------l ~IRST STAGE OEVt:LODMENT, CRATER LAKE:.
RECOMMENDED POWER TUNNEL
)" .. ·~4~if',.ll CJ$$~
, L -, ve" 1,<4",,' ,/s'"
GRAPHIC SCALES
DESIGN MEMORANDUM NO. 23 PLATE 21
CORPS OF ENGINEERS
EDGE OF
TURNOU T
ED (JE OF ROAD ------;~ I
L-I
I
---ROCI( FILL
SECTION C-C
SCALE
t ROAD
SEE TYPICAL RO~_O
:-sUTION-S---------1r-
GROUND
," 6"
~ '~~,".'~~ t'dii~
1-1/2"-,' " !V8"" ,,,",",,' fIe".,'
G""PI-1IC SCALES
(~
c.'l.iV
u.s. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
U. S. ARMY
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE.
RECOMMENDED POWER TUNNEL
DESIGN MEMoRANDUM NO.23 PLATE 22
CORPS OF ENGINEERS
-+
CRATER LAKE
U. S.ARMY
--
u.s ARMY ENGINEER DISTRICT. ALASKA
CORPS OP ENGINEERS
Dr-;'C''''~Ll --,------------------j
?,,;, SNETTISHAM PROJECT, ALASKA
c..vv
FIRST STAGE DEVELOPMENT, CRATER LAKE
RECOMMENDED POWER TUNNEL
ALTERNATIVE GATE STRUCTURE
ACCESS ROAD AN-SH.I
PLATE 23
CORPS OF ENGINEERS
( ~)
--,-
PROVISIONS,
tOO' 0'
10 •••• '
GRAPMIC SCALE
100' 200'
I
I", 100 -0'
U. S. ARMY
TAP EXIST
O.H. LINE
U.S. ARMY ENGINEER DISTRICT ALASKA COR::~H~'::'G~N ... :~~;"ERS .
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
RECOMMENDED POWER TUNNEL
ALTERNATIVE GATE STRUCTURE
ACCESS ROAD AN -SH. II
~ECO M ~
DESIGN MEMORANDUM NO. 23 PLATE 24
CORPS OF ENGINEERS
\
\
-I-
I
'. / ,.'U
", ~\. /,:
\"'COHCRUE TESTING Lola "/ ff .}.4~
at
7
COOIIOIl'U,T[,
11'41"
[.Ul7
\
I
I
",0' 0' ",0' 10' ~~-==--~~I .... .tl====~i
G"APHIC SCALE· 1".40'-0'
~I
/
+
-
I ----... --
LEGEND
NEW CONSTRUCTION r=::J
CUT OR F,lll Sl.QPE ~
SEWEALINE --5-
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
U. S. ARMY
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVEL0PMENT. CRATER LAKE
CAMP
, CORPS OF ENGINEERS
D 200
Toilroa Tl.lnntJ./
/
/
~ ------
\_~-~
S,;/fch/ord
EJ 20,0
-0' ....-,. -..-
~. 1 '. '.
", I
, I
!
___ Addi-J./on.::,( cq<./~P 7I#'nf
;Jr7Cl~d +0,--C ~a"'e'-
... oK!? Un, f /\,'.101.5
FI.-5.':-
U, S. ARMY
T T
NOTE
U. S. ARMY ENGINEER DIVISION, N.P.
SNEITISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT
POWERHOUSE
GENERAL
POWERHOUSE AND SWITCHYARD
GENERAL PLAN
DESIGN MEMORANDOM Ni 23
Zi /:; {
>-'f, "t?( II! ! c
PART PLA'~ F I lJ'~ IT 3 r~cfv1~~C TF
:-,,_ ~11, IF< • I -
C'c'"
~r ,'v'
Pre
\,~ S !
5ECTI_'1\
I 0
5[:O'~; ('':-:/~;: ~'VJ
~/'iQ '(.JI
'oE:JI)~ A-A
THPIJ SK[L=:T)N BAY
'/8 I' )
~~-S""e-'!/
Sfcnr5
UAIL
-----_ D "-., "--k , F' • ~~ '"
U. 5 ARMY ENGINEE~------" _~l Af.D ORE~~~15rON, N P
SNETTISHAMPR -F-IRST STAGE ,QJECT ALASKA-
DEVELOPMENT
POWU,HO'JSE
ARRANGEMENT
CRATER LAKE UNIT 3
"K~'oc' "IJK'O,ui/:;-,,{" "-,,_,,/JVC;:-~c \~I\<::)'~ I _~'x_":--d£'c:;~HI ,~~ ---'~~S-'-~--L_:1'SNP-O-O-O/I 1
5
;';:;-:;-
MEMORANDOM N.--z3·-----'--~ PLATE 27
COIl'S Of ENGINEUS
i
rDAM SITE
\ STUDIED
I
CR!1T[R LAX[
.. ::. (l [\; • I '~22
STRUCTURE
\
;CRATER LAKE
POWER TUNNEL
Q ~:::O ~'"'
j;EXfST TRANSMISSION
LINE
( ,
? X STAR
JETTY -
x
-'--2200
18C:J _
000
':
AOIT PQRiAL
~~->
EXI5T1NG .Jccess 1101 r ROAD
EXISTiNG
PEN5TOCK
MOUNTAIN
------------',
60:;
I tI':JI!Y~
uPPER t.U[;,S ROAD"
,
/ "" __ 4-~-BOBROW AREA NO. a
~) PtE L
\
\-PROPOSED
SEWAGE LAGOON
CONTRACTOR
CAMP
~
,~ POI~~ '\ --<: \ \
\, \ '\ \ "
'\ l~<\
"'-..
,\
5.
x.
--:(
/
,_ f::.J'[
J
/
/' X
_____ BM)-'
,(1('0
___ 1200 -
u. S. "."'"
MOU~TAI,"
ccOQ
x-i>ooo
./
1800
~ / -
1600 /r
~20(1
I ,
r
U.S, ARMY ENGINEER DISTRICT. ALASK"
CORPS OF £NQIN££M
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
PROJECT GENERAL PLAN
INTAKE STRUCTUR
RU_
I-SNE-96-01-01-07!3
DESIGN MEMORANDUM 23 PLATE 28
CORPS OF ENGINEERS
SECTION ill
\tV
U. S. ARMY
I
---I:~-::'~ 0 _-~::~~~t------l iF~~~~~~c======~~~== -I
I i I:IEL~' -------
i
~I
L
\
BULKHEAD SLOT \
~ -I L~ ,1 "'[ 11
'0' °l~ ,I .----.-~-l' ~J __ ~r<J~~~:';'(kl-kko(I~oI1\~11 ~III ~I J ----1-~
PLAN
5CALE-' -'-4--1' 0'
c
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
INTAKE STRUCTURE ALTERNATIVE
INTAKf;
'\
DESIGN MEMORANDUM NO. 23 PLATE 29
CORPS OF ENGINEERS
\
1150
1100
1050
W.S. ELEV. I020±
1000
950
900
850
80
750
0+00 2+00 4+00
-PLUG GATE STRuCTURE
\
/ '~
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SLOPE_ O,OO~ ~~=======================~ --------0:
CRATER CREEK
6+00 8+00
CRATER LAKE DIVERSION
200' IO"~riIlll:.I.I.:Io 0, __ t::===:::jl
GRAPHIC SCALE r". 100' -0'
HORIZONTAL
100'
~o 100' ""c=--~Ji::===?-' ~~I
GRAPHIC SCALE. I", ~O· o·
VERTICAL
10+00 12+00 14 + 00 16+00
TUNNEL
U. S. ARMY
U S ARMY ENGINEER DISTRICT. ALASKA
• . CORPS OF ENGINEERS
.... "'CHO" .... "" .... ~ .... M ..
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
INTAKE STRUCTURE ALTERNATIVE
DIVERSION TUNNEL
I-SNE -96~02~16-03/1
SHEEr OF-
PLATE 30
CORPS OF ENGINEERS
CRATER LAKE
w.s. /022:!.
c-===
END ROAD
STATION
--L ,
(
I
I
100' 0' I~O'~O'
10 •••• ' , ~
GRAPHIC SCALE 1"-100'-0
DESIGNED,Fh.c
CHECKED
(.VY
----\
U. S. ARMY ENGINEER DISTRICT, ALASKA
CORPS OF" ENGINEERS
U. S. ARMY
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
INTAKE STRUCTURE ALTERNATIVE
ORANDUM NO. 23 PLATE 31
CORPS Of ENGINEERS
CRATER Lt.KE
/
/
CR4TER
c,---a.-;J
( JEXIST TRANSMISSION I LINE
I ? X ST.1R pOlr_~I. /f F-~ __ .00 ;;::~
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CONTRACTOR
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PROPOSED
SEWAGE LAGOON
NO. 2
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U. S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
F~ ~~ Ts~~~~ ~~Eto~2~~~.T CR! MS ~A~E
PROJECT GENERAL PLAN
L ALTERNATE
DESIGN MEMORANDUM 23 PLATE 32
CORPS OF ENGINEERS
PLAN
~I
."" I,. C:T, JT ~~~ 1 5---'~r
I
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, f. POWER TUNNEl~ -41
----------,-' ,.
AT GATE ROOM FLooJ
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U. S. ARMY
~~-=~-------~~--------
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U.S. ARMY ENGINEER DISTRICT, ALASKA
CORPS OF ENGI"'IEERS
SNETTI SHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
POWER I ACCESS TUNNEL ALTERNATIVE
DESIGN MEMORANDUM NO. PLATE 33
CORPS OF ENGINEERS
PQliER ACCESS TUNNEL ~ ~ -. J .. -~ -r-----=--= ---~~ ~-~-=-::-~ . _ -_______ _ -~----1--1----------.. t,,,,,,
: ~'ArC~)S ADIT
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34 :,U,'_f
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U. S. ARMY ....
Y ENGINEER DISTRICT. ALASKA U.S. ARM CORPS OF ENGINEERS
.. N'-"O .... G£ ... LASKA
PLATE 34
CORPS OF ENGINEERS
PLAN
SCALE I"· 50 ~ o·
ELf\! IO!:l7'
O+OQ
Ir-""""-~""~-"""~~---
CONSTRUCTlO~ JOINT
25' DAM -CRATER LAKE
ELEVATION
21' 16
U. 5. ARMY
SPILLWAY SECTION B
U.S. ARI\-IY ENG;".,[:;:ER DISTRICT, ALASKA
OF E.NGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
CORPS OF ENGINEERS
PLAN
[LEV 99Y
"'"00
.,.1..---
,0
20
PRESENT LAKE LEVEL I~ -\ - ----::::-""--=-- - - - - -
~-----'-----
---------~
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TYPICAL SECTION A
SCALE ,". 10'-0' 36
r _~LEV~'~0~12~ ______________ -, _________________________ -, __________________________ ~
O+9~
t-----CONSTRUCTION JOINT_
// ----------'----;---L-------
2'20
50' DAM -CRATER LAKE
ELEVATION
SCALE' .". IO'-C'
SPILLWAY CREST
~
U. S. ARMY
\]'0'
'0
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SPILLWAY SECTION B
ELEV 993'
SCALE I"' 10'-0' 36
/
ELEv 1082'
-----
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~~-~~--=--=-====~=======q
O~IG~'>O
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DRA"'N~
U. S. ARMY ENGINEER DISTRICT, ALASKA
CORPS OF ENGINEERS
---SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
50 FOOT DAM
CORPS OF ENGINEERS
QHP TO
SWITCHYAAO ji
APPROXIMATE LOCATION
~h'---EXISTING CRATER COVE
HAUL ROAD
U. S. ARMY
L r:GE ~o
U. S. ARMY ENGINEER DISTRICT. ALASKA
CORPS 0. ENG!NEERS
CORPS OF ENGINEERS
DIAM OF HOLE,
% RECOVERY
COlllf'lU:O 8'1', DATE
,<><. REMARKS
N ~.'
E SURFACE EV
SUMMARY LOG -----nc_ . ____ ._L __ ... ....5I!E.E.I 4
HOLE NO. E SURFACE ELEV
. C";'
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ANGLE FROM _VER~ __ l AZIM~.!H FROM HO~~H__ COIllPiLED 8'1', DATE I
DISTANCES' V;;:RTICAL ' HORIZONTAL I
SUMMARY LOG
HOLE NO. '"
U. S. ARMY
SUAFA EV.
PROJECT.,," '~, ,·,·"tc" COMPo
-=~~TH "'-HOLE------I-oEI'TH ;;;:~VE'.-"ROEN OI.M. OF HOLE
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~~GLE ~_R.?_~~:r_ AZIMUTH FROM NORTH .____ COIIIPlLlO BT, DATE
DISTANCES' VERTIt;AL . HORIZONTAL
,<><.
to 1,; ft.
17: lo 112
REMARKS
Cere lengt!ls
0,1 to4.0f:.
~Q"~ 1 el',gths
0,3 tQ2.0 ft
c('., ~ 1.'ngL'ls
L.OS to 1,2 '-t.
u.s. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
EXPLORATIONS
NO.1
DESIGN MEMORANDUM NO. 23 PLATE 38
CORPS OF ENGINEERS
I.", ! ~~ __ ~~ ___________ ._'_" __ ~IA~~. ____ '_E_.'_'_'_S ____ ~
II I
I
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PROJECT ~net~l ,nan,
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ROCK DRILLED fCORE RECOVERED i% RECOVERY
ANGt..E-FROM VE~ A".z-U,iUTH FROM NORTH ·eOIllPlL!O 8'1'. OATE
OIST-ANCES~ VERTlC-A-L ----HORIZONTAL 1
REMARKS
C~re I en'I';11>
0.02 toO:; Ft.
BCTTiJMIJ"rl()LL
PROJECT S1eLLI"ram (eratH LM'~,
U. S. ARMY
IOIAM OF HOLE
1% RECOVERY
COIrolPlLEO 8T, OATE
, r~nlth;
,1lc I r: f+
HOLE NO. DH I
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
PLATE 39
CORPS OF ENGINEERS
1
:J
I
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U. S. ARMY
.-'----.. ~~---
u.s. ARMY ENGINEER DISTRICT, ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
BORROW AREAS
AUGER HOLE~ NO. I
DESIGN MEMORANDUM NO. 23 PLATE 40
CORPS OF ENGINEERS
i
'--+,c:",-"-:,,,:::,"',---,,-., -C-O"-,,-•• -"-n8U~;;---~
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U.S. ARMY ENGINEER DISTRICT. ALASKA
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
BORROW AREAS
AUGER HOLES NO.2
DESIGN MEMORANDUM NO. 23 PLATE 41
CORPS OF ENGINEERS
TP 37
~
SA~ Dr GR AVEL
G'
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2B OCT 6W J
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28 OCT. 64
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LEGEND
FOR TEST-PIT LOG SHEETS
TP 22 -EST PiT ~WI~BC:R
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SeAVELLY s",J
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9.5
16 NOV 61< -'~ATER TABLE & DATE IJBSERVED
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DEPTH OF PIT
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PEAT AND ORGANIC SOiL
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U.S. ARMY ENGINEER DISTRICT, ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
BORROW AREAS
U. S. ARMY
DESIGN MEMorfANDUM NO. 23 PLATE 42
CORPS OF ENGINEERS U. S. ARMY
SAND I'll TH
FE '~' PEBBL E S
SANDY GRAVEL
GRAVELL Y SANJ
SAN]
~l TH FEI', PEBBLES
18 0
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£ 'JIFFLt
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NOH S~E '>'EE: 1~5 F1R TEST Pl1 :~[GUJ
U.S. ARMY ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
SNETTISHAM PROJECT, ALASKA
FIRST STAGE DEVELOPMENT, CRATER LAKE
BORROW AREAS
TEST PITS NO.2
I-SNE -96'-OI~08-03/6
rA
DESIGN MEMoRANDUM NO. 23 PLATE 43
SNETTISHAM PROJECT
ALA~SK.A
SECOND STAGE DEVELOPMENT
LAKE TAP STUDY
WITH
RECOMMENDED ARRANGEMENT
fOR
CRATER LAKE
PI(EPARED BY:
INGENI0R CHR. F. GR0NER
CCNSULlING ENGINEERS
;: h' b 'f I _ X I I
SNETTISHAM PROJECT ALASKA
SECOND STAGE DEVELOPMENT
LAKE TAP STUDY
RECOMMENDED ARRANGEMENT
FOR
CRATER LAKE
Oslo, Norway, January 1973.
ESol/jb
TABLE OF CONTENTS
1.01 REfERENCES........................... 1
1.02 GENERAL.............................. .i
1.03 LAKE TAP ALTERNATIVES .. ..... .... ..... 3
1.04 LAKE TAP RECOMMENDED ARRANGEMENT..... 7
1. 05
1. 0 b
1. 07
1. 08
1. 09
POHER TUNNEL ......................... 12
INTAKE CONTROL GATE .................. 12
INTAKE TRASH RACK............... ..... 15
ROCK TRAP -SURGE TANK -PENSTOCK INTAKE 17
PENSTOCK ............................. 18
1.10 ROAD ACCESS .......................... 19
1.11 SEISMIC CONSIDERATIONS. ..... .... ..... 20
1.12 RECOMMENDATION....................... 20
DRAWINGS :
No 1551-101 -
-102 -
Power Tunnel alignment -Lake tap
" " -Penstock intake
-103 -~ake tap, single stage & 31ternative
-104 -Lake tap, two stage
-0-
1. 01 l<cferellCeS. -'flit.: ful1uwillg Ldkl' lell)
study has 1)0cn completed u.ntle l' con tl'J,~ t No.
DACW 85-73-C-0023 and is bd~jt;d UIl UIl'
following information receiveu.
Letter of November 30. 1972 with inclosed:
Contour Map, Profile, Geological report.
Letter of December 5, 1972 wi~h inclosed:
Writeup, Photos, Maps.
Letter of December 19~ 1972 with inclosed:
Copy of underwater geophysical investigation.
Letter of January 3, 1973 with inclosed
Boring logs for five drill holes.
Letter of January 10, 1973 with inclosed
Plan and profiles.
It is further referred to our preliminary lake tap
study mailed with our letter dated December 13.,
1972 and our letter of December 20., 1972 following
a phone call of December 19., 1972.
1.02 General. -The purpose of this study is
to arrive at a recommended layout for the intake lake
tap of the Crater Lake power tunnel. In our
- 1 -
preliminary study, su~mitted in December of 1972,
for this specific lak2 tap, four alternates was
considered. The additional information on geol~gy
etc. received since t~en, permits at this stage a
recommendation for the Crater Lake project.
However, as further data is obtained from additional
explorations the recommended ')lan must be changed
as required, this in connection with lake taps 1S
only a normal procedure~ In this connection we
notice that a comprehensive exploration program,
in the vicinity of the lake tap, is scheduled ~or
this summer.
In the following the various aspects of the alternates
will be discussed, and waterway features, affected
by the lake tap, will be referred to as required.
The lake tap invert is now established at elevation
800, with a minimum operating pool at elevation 820.
With the selected tap invert,the tunnel invert
immediately downstream is at elevation 775 in
consideration of the lake bottom surface profile.
The tentative slope for the power tunnel is indicated
as 0.5 percent, and the tunnel cross-section is a
10 ft. diameter modified horseshoe shape .
. -2 -
IN6ENIIZIR
t:HR.F. EiRIZINER Ft=.
1.03 Lake tap alternatives.-Initially, 1n our
preliminary study submitted in December of 1972, four
alternates were considered for the lake tap.
As more information became available the two first
alternatives suggested obviously would be less
practical than the remaining alternatives 3 and 4.
The following study will consequently basically
consider the merits of alternative 3 and 4 but a short
description of alternative 1 and 2 is included 1n
order to complete the picture. (Reference in this
connection is made to drawing 1551-01 and 1551-02 of
the preliminary study):
The basic feature of alternative 1 and 2 1S the
very deep invert recess operating as the rock trap.
The trap arrangement 1S effective and has been used
mostly with low head taps. Before using this
arrangement with a high head tap however, a few
important questions should be carefully considered.
Stable rock conditions and preferably no leakage
water in the tap area would be of major importance
considering the project safety.As regards cost, the
excavation rates should further be relatively
reasonable in order to justify the arrangement.
Although the trap arrangement is effective,
excavation work is, even under the most favourable
conditions, time consuming and difficult. Drilling
and loading of the final round across the deep
recess is a problem that requires special attention.
- 3 -
IN5ENll2IR
HR.F. aRIZINER A.S.
If the geology of the tap area should show joints
parallel the lakeside rock surface we would even
with very little leakage water advice against using
this arrangement at Crater Lake. The arrangement is
designed to arrest permanently in the tunnel system,
rock fragments from the final blast without inter-
fering with subsequent operation of the power tunnel.
For the Crater Lake project it would, in comparison
with arrangement 3, offer no actual advantages.
•
It is rather so that with a complex geology combined
with great depth as the Crater Lake project features,
the arrangement must be rated as unpractical in
comparison with arrangement 3 of the preliminary study.
With the dismissal of arrangement 1 and 2 our present
study will consentrate on comparing the arrangement
3 and 4 of our preliminary study. The previous
arrangement 3 will be recognized as the recommended
arrangement in this study with arrangement 4 as a
possible alternative. The two arrangements are shown
on drawing 1551-103.
The recommended arrangement is designed with a rock
trap for permanently holding back the rock fragments
from the final blast without imparing subsequent power
tunnel operation, whereas the alternative arrangement
is designed to dispose of the rock fragments of the
final blast through a discharge tunnel to the surface
downstream of the gate shaft.
- 4 .-
\
INIEiENII2lR
t:HR.F=. EiRIZINER A.5.
With the a.lternative arrangement the illldk.e gdlt~
must be cloGed some time after the filldl blilfit jn
order to control discharge velocity dllJ volullle.
Until the gate is closed rock fragments from the blast
will consequently pass the gate structure.
Although damage to gate seats and the gate leaf
under these conditions is not likely, the possibility
cannot be entirely dismissed. In order to minimize
damage to vegetation etc. along the creek bed
receiving the discharge water, volume and velocity
would mostly be restricted by the authorities. The
timing of the gate closure under these condition
will always leave the uncertainty as regards
distribution of rock fragments on the tunnel invert
upstream of the gate. With a relatively short tunnel
length between the tap and the gate shaft the timing
problem is hardly critical. As soon as this tunnel
length increases however the problem becomes
progressively more difficult under the above assumptions.
If, on the other hand, a large volume of water can
be used at relatively high velocity, and with little
or no consideration of damage to vegetation etc.
along the creek, tunnel length inside reasonable
limits would present no difficulty and the uncertainty
with respect to rock fragment distribution would be
negligible.
- 5 -
INGENU2JIQ _
tR.F=. ISRIZINER FI.5i.
Summarized the alternative arrangement could be
of advantage for Crater Lake under the following
conditions :
1. Extremely complex geology with unstable
rock strata in the tap area.
2. Relatively heavy overburden, where it would
be difficult, if at all possible, to
estimate the amount of this overburden that
would be released following the tap blast.
3. Cost of the discharge tunnel, including
temporary power tunnel closure and the later
permanent plug of the discharge tunnel, should
not be higher than cost of rock traps of the
other arrangement.
4. Essentially no :='imitation as to water
volume and velocity of discharge following
the tap blast.
At the present stage of the exploration, point 1 and
2 apparently do not apply to Crater Lake. We further
feel that the cost comparison indicated in point 3
would not favour the discharge tunnel.
As for point 4; a rather unrestricted discharge even
for a shorter perioee would possibly cause severe
damage to vegetation along the creek bed receiving
- 6 -
thp. WOlle'f' .11](1 th<? ~;illliltlon wfl\jlcj ildT'dly l)(' PO!,UJdl'
with conservationists.
In this section the alternative lake tap arrangements
for Crater Lake have been discussed indicating the
criteria for eventually selecting these arrangements.
Since the explorations for Crater Lake at the present
stage does not indicate conditions that would favour
any of the above alternatives, the recommended arrange-
ment for Crater Lake is presented in the following
section 1.04.
1.04 Lake tap -Recommended arrangement. -
The recommended arrangement is shown on drawing
1551-101 and -103 and will be recognized as the
arrangement 3 of our preliminary study.
Since submittal of our preliminary study, we have
received general information on the geology of the
area together with drilling logs for hole 98, 100
and 102 at Crater Lake and hole 99 in the surge
tank area.
Although the area at Crater Lake is more fractured
than the rest of the project area there is no
indication of unusual rock conditions in the ~ap area.
The under water geophysical investigation indicate
that favourable cond~tions for a lake tap could
exist over some 100 ft. of the lake bottom at
elevation 800. We agree with you however that further
investigation here must be considered in order to
- 7 -
establish the joints and faults possibly exi~;ting
in the tap area. In Norway we have in similar
situation3 successfully cdrried out s~ismic SUIV!
of the lake side rock struc~ure of the tap are6
through surveyed holes in the ice cover of t1.e lake.
The geophysical investigation further shows that
no overburden is indicated above elevation
800, this we hope will be confirmed by the additional
exploration of the tap area.
The information available at this stage indicate
that the tap arrangement selected for Crater Lake
should be the layout shown as recomme~ded on drawing
1551-103.
The recommended arrangement features a dead end
tunnel section operating as the main rock trap
designed to arrest permanently the ~ock fragDents
from the final blast without impairing ~Jubsequelit
operating of the power tunnel. The rock trap is
connected to the power tunnel through an overflew
in the s ide of the dead end sect i on. The drd .... l i llg
shows a single stag~ tap with the tap point location
in accordance with the lake bottom surface profile.
The tunnel section towards the tap rlse lS generally
the 10' diameter modified horseshoe shape of the
power tunnel but with soffit enlargement for the
overflow and a widening from 10 to 15 ft. for the
last 45 ft. of the dead end section. In addi tiOll
the arrangement features a secondal'y tra.p with
wedge shaped concrete sill on the power ~unnel 30me
2 SO ft.
- 8 -
INEiENllZIR
r::HR.F.ISRIZINER R.§;.
upstream of the gaTe shaft. The outli)le~; of this
arrangement follow the rec,rrtmendat i on:; of mode 1
stu die sea I' r i e dOli t for 1 a k eta p ~~ S tl C c, > :; :; f u 11 y
executed in Norway wi th cO:iJitions very mUC,1 the
same as for the Crater Lake project.
With the recommended arrangement the lake tap is
suggested executed with no water in the power
tunnel and the bulkhead gate closed. In this system
the water entering the tunnel, following the tap
blast, will be slowed down by a gradual compresslon
of the all' ln the tunnel, and the shock trail:; fered
to the closed bulkhead gate will not be critical.
In the model studies referred to the efficiency was
recorded, with up to 86 per cent of the rock
fragments collected in the dead end section, 11 per
cent in the secondary trap and the rest scattered
along the tunnel invert upstream of the gate. The
target for the study was to have no rock fragments
reach the gate shaft and this was achieved with
the recommended layout. Inspection of the proto'ype
in order to establish the relationship between
prototype and model has not yet been possible for
these projects, but plant operation is reported
entirely satisfactory.
The excavation cost for the recommended trap
arrangement is higher than for the trap of the
alternative.
- 9 -
INGENilZlR
IR.F. SRIZINER A.S.
For Crater Lake however this should be offset by the
cost of the discharge tunnel required with the
alternative.
Unstable rock conditions will normally not be a
special disadvantage with the recommended arrangement
since the rock can be secured operating from the
normal tunnel invert using conventional tunneling
technique.
The following maln reasons can be established In
connection with our recommendation
1. Unusual rock conditions In the tap area is
not recognized from the present geologic
exploration.
2. No overburden is suspected above the
elevation of the tap.
3. Total cost of recommended layout is not
considered higher than for the alternative.
4. Damage to nature through discharge to the
surface does no~ apply.
5. The arrangement has bee~ model testet for
similar projects in Norway successfully
executed in accordance with the recommendations
of the model tests.
-10 -
INEiENII2IR
I::HR.F.I5RIZINER R.S.
With ret('l'CIlCe to the generally capcltllc r'ock existing
in til i~, drc a and the further lcJ.ck. 01 ove rbunh:n we
consider a single stage tap entirely feasible at the
depth required for Crater Lake. If however later
exploration should indicate that conditions of the
tap area is somewhat obscure a two stage tap could
be advicable for this depth. The same would have
applied to the alternative if selected.
With obscure conditions in the tap area and with a
water depth of 200 ft. or more a second tap point
could be introduced for safety. If something should
go wrong we would, with two taps even under the
most difficult conditions, have established openlngs
big enough for a draw-down of the lake. Remedial
treatment of the intake could then follow from the
outside.
We are for Crater Lake positively not thinking
that a two stage tap will be required, for general
information however we are on drawing 1551-104
showing the geometry of a two stage tap with the
recommended arrangement.
Our present recommendation for Crater Lake is a
single stage tap directly on the power tunnel with
no separate diversion tunnel as at Long Lake.
-11 -
1.05 Power tunnel. -With the mup material and
geologic interprelatlon of the urea received since
submittal of our preliminary study, we are now
considering the possibility of a straight power tunnel
alignment between the gate shaft and the surge tank
area. The alignment is shown on drawing 1551-101 and -102.
An alignment change if required should not affect
the other features of the project.
The power tunnel in our opinion could be an unlined
structure with dental concrete and shorter sections
of lining at the intersection with main joints
and faults as for the Long Lake project.
Requirement for lined tunnel sections could
possibly be greater for Crater Lake than it was for
Long Lake. In consideration of the possible type
of debris at Crater Lake we are now rather contemplating
locating the main trash rack at the power tunnel
intake in Crater Lake. Our reason for this will be
discussed in section 1.07 Intake {rash rack.
1.06 Intake control gate. -On drawing
1551-101 we have shown what we consider the most
favourable location of the intake control gate for
Crater Lake. The gate location should be as close
to the intake as possible, only restricted by
topography, the known joints and faults and the
closeness of the tap point. Considering these items
we have shown the gate shaft somt 750 ft. from the
-12 -
tap point. The elevation of the top of the shaft is
tentatively established at El. 1040. If the full pool
W.S. however is defi~itely no higher than elevation
1020, the 1040 elevation could possibly be set at
1030.
Access to the top of the gate shaft is shown through a
800 ft. long tunnel. The same tunnel is further
suggested extended approximately 500 ft. to the
trash rack cleaning station at Crater Lake. The
portal of the gate shaft access tunnel is shown in
the same area as the end of your proposed access
road. With the steepness of the rock formation of
the eastern rim of Crater Lake we feel that a
conventional road access to the lake would be both
expensive and inconvenient and should favour a tunnel.
The gate shaft in our layout contain an upstream
bulkhead gate and the main control gate. The gate
shaft is a wet well as would be the solution for a
similar project in No~way. The major reason for
selecting this type of system in Norway is cost.
Bonnet type gates for the bulkhead and the main gate
and located 1n a dry well would be rather expensive in
Norway. Although operation of the gat€s in a wet well is
rather inconvenient and espec~ally so for the manually
operated bulkhead gate, the situation 1S mostly
tolerated. The main gate of the wet well is operated
through a steel profile gate stem extending for the
depth of the shaft and supported against a number
-13 -
IN5ENlmR
-IR.F. GiRlZlNER R.5.
of brackets bolted to the shaft wall. The main gate
is hydraulically opened but shuts hy weight of the
gate leaf ones the control is engaged.
With the bulkhead gate closed the gate shaft can be
drained for inspection or repair of the main gate.
Hoist maschinery for removing the gate leaf from the
shaft is located at top of the shaft.
In design, the bulkhead gate should be dimeTi~' iOJicd fur
shock as the bulkhead will be closed at the time of
the tap blast in accordance with our recommendation.
Considering the posibility of severe seismic
activity in the Crater Lake area we feel that the
long gate stem of the main gate and the gate guide
structure for the bulkhead used with wet wells in
Norway, should not be adopted for the Crater Lake
project. In our opinion the bonnet type gate both for
the bulkhead and the main gate,and located In a dry well
should be an advantage for the Crater Lake development
under the above consideration.
The length of tunnel lining required adjacent the
gate structure would be dependent on the join~
pattern in the vicinity of the gate shaft. With a
competent rock structure only very short sections
need be considered. At the bottom of the gate shaft
we further suggest a protective concrete slab errected
above the gate bonnets in orde~ to absorb the impact of
possible minor rock falls in the shaft following
seismic activity.
-14 -
Leakage water to the dry shaft should be considered
and a pump well with pump will be required at the
shaft bottom.
1.07 Intake trash rack. -Our intake
arrangement suggested for Crater Lake eliminates the
conventional layout with trash rack and gates in one
intake structure. With the control gate and the bulk-
head located in the gate shaft,the trash rack is
considered at the intake opening in Crater Lake. We
are suggesting a removable type positioned following
the first operational drawdown of the lake. Rail
track would be errected from the trash rack cleaning
station towards the intake as the lake water recedes.
The support structure for the trash rack at the intake
opening should be errected with water at elevation 800.
Details of this arrangement should be layed out as soon
as the condition at the tap opening is known. The main
trash rack for the project is now considered for the
intake in Crater Lake. Having studied the
photos received we see generally spruce covering the
lake rim. If tall leaf vegetation is absent or only
rarely presenL in the catchment area we would hardly
get the rack clogged by a mixture of twigs and
leaves which represent a most troublesome combination
for some of our projects in Norway.
The lake 1S in addi~ion only operated below its present
maximum level which means that no timber covered
areas will be submerged. Under these
-15 -
circumstances we feel that it would be justified
to have the ma1n trash rack at the irltake opening in
Crater Lake rather than at the penstock intake as
suggested in our preliminary study.
For the main trash rack the bar spaclng should be
selected in consideration of the debris to be
expected that could harm the turbine. The turbine
runner characteristic will at normal operation permit
passage of a certain size of debris.
The clear opening between bars of the trash rack
should be selected i~ consideration of this. If the
Crater Lake turbine will allow, we suggest a 2 inch clear
space between bars of the trash rack. With this
space sturdy branches and timber that could give
trouble in the tunnel is caught whereas lesser twigs
should pass.
Cleaning the rack would be carried out either by
pulling the rack up to the cleaning station or by
lowering the cleaning equipment on a rail mounted
platform to the water surface above the rack.
Errection of a rail track for this purpose is
dependent on a reasonable surface profile between
the intake and the cleaning station.
Lesser problems could at times be expected from
the ice in the lake.
-16 -
1.08 Rock trap -Surge tank -Penstock intake. -
The rock trap arrangement shown on drawing 1551-102
In the downstream end of the power tunnel is based
on recommendations from model studies for similar
plants in Norway with unlined power tunnels. Provided
that the power tunnel is reasonably clean at the
start of operation the holding capacity could be
sufficient for two years continuous operation.
We have tentatively positioned the surge tank as a
vertical shaft practically at the location of
drillehol/e 99 approximately 50 ft. distant from the
nearest known fault. In consideration of this fault,
a sloping tank could be favourable for the project,
more information however would be required in order
to make a recommendation in this respect.
With your letter dated January 10. arriving here
January 15., we received an unnumbered drawing
showing the penstock alignment. Our drawing 1551-102
assumed a possible location of the top of the penstock and
the surge tank aroLnd drill hole 99. However having
studied the problem we have in section 1.09 suggested
a relocation of the penstock. This realignment will
possibly also require realignment of the power tunnel
in the sugrgetank area. Our drawing 1551-102 is
consequently not at this stage representative with
respect to final location of the top of the penstock
and the surge tank.
-17 -
As for the connection between the surge tank and
the rock trap it is suggested that the opening is
located high on the side wall of the rock trap to
reduce disturbance of the trap collecting efficiency.
The invert of the penstock intake is elevated 6 ft.
above the rock trap invert in order to curb migration
of smaller rock particles from the tunnel invert
to the penstock. With the main trash rack now suggested
for the intake in Crater Lake, only a half rack
should be required at the penstock intake.
1.09 Penstock. -Reference is made to the
penstock alignment and profile shown for the project
on an unumbered drawing received with your letter of
January 10. 1973.
The alignment shown would require a steel liner
designed for the full ~ydrostatic pressure in order
to minimice load transfer for the rock structure
as close to the surface as shown.
In order to meet the general requirement for rock
cover of an unlined tunnel ein this case the rock
trap at the downstream end of the power tunnel) we
would recommend the steel lini~g to be installed
also in the horisontal connection between the top
of the shaft and the downstream end of the rock trap
at the surge tank.
-18 -Rev. Mar 73
From the plan of the su.rge tank area it appears
that it could be necessary to relocate the surge
tank, further investigation planned should clarify
this. Because of the faults present a tank sloping
towards the west could be an advantage.
1.10 Road Access. -The road access shown
on plate 2 submitted with your letter dated December
5.,1972 ends in the vicinity of the portal of our
suggested tunnel access to the gate shaft and
Crater Lake, see our drawing 1551-101. In addition
road connection will be reqired to the portal of the
power tunnel construction adit shown on drawing
1551-102. Road access to the surge tank ventilation
opening should not be required but the decisioD
should await the final solution in connection with
the surge tank layout.
-19 -Rev. Mar 73
1.11 Seismic consideration~. -The Crater Lake
power tunnel will be constructed across ma=or joints
and faults of the project area. For the power tunnel
we assume that as for the Long Lake project remedial
treatment in connection with intersection of joints
and faults will be directed towards leakage control
and replacement of crushed and faulty rock materials
with dental concrete. With the layout now recommended
for the Crater Lake project seismic damage to the
power tunnel downstream of the gate shaft can be
repaired as long as gate operation is possible. With
damage to the gates or the power tunnel upstream of
the gates a secondary outlet from Crater Lake could
be required to permit repair work.
A separate diversion tunnel however is not
required in connection with the lake tap or the
normal operation of the project.
1.12 Recommendation. -With the information
received since submittal of our preliminary study we
are now recommending for the Crater Lake project the
layout shown on our drawing 1551-101 and -102 with a
reservation in connection with the surge tank area
mentioned in sectivn 1.09.
The tap arrangement recommended is shown in detail
on drawing 1551-103 and a possible two stage
arrangement for the same o~ drawing 1551-104.
-20 -
IN6ENIIZlR
EHR.F. EiRIZINER FI.Ei.
Our recommendation is for a lake tap directly on
the power tunnel omitting the need for a separate
diversion tunnel.
The intake arrangement with bonnet gates located
in a dry gate shaft is favoured over the wet well
arrangement indicated on the drawing.
The main trash rack is now recommended at the
intake opening in Crater Lake rather than at the
penstock intake.
In connection with the additional exploration
planned for the tap area we consider locating joints
and faults in the tap area and the immediate
vicinity to be of major importance.
OSl~a~U ~73.
UI'~' C. F. r¢ner
-21 -
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SNETTISHAM PROJECT ALASKA
REPORT FROM
the
ANCHORAGE CONFERENCE --------------------
of
FEBRUARY 8 9 -1973 ----------~---------
Oslo Norway February 1973.
Exhibif .2
TABLE OF CONTENTS
INTRODUCTION ...... "..................... 1
1. THE EARTQUAKE RISK ..................... 2
2. BULKHEAD AT THE INTAKE OPENING ......... 3
3. LAKE TAP ALTERNATIVE ................... 4
4. NUMBER OF GATES ........................ 4
5. INTAKE CONTROL STRUCTURE ...... ......... 5
6. ADIT TO TOP OF GATE SHAFT .............. 5
7. TRASH RACK LAYOUT ...................... 6
8. TUNNEL LINING TO RESIST EARTQUAKE ...... 7
9. DISCHARGE THROUGH SURGE TANK ACCESS ADIT 7
10. POWER TUNNEL ALIGNMENT ........ ... ...... 8
11. BLIND TUNNEL ORIENTATION.... ........ ... 9
12. SHOCK LOAD ON CLOSED BULKHEAD. ......... 9
13. VENTILATION, GATE SHAFT ................ 10
14. INTAKE TRASH RACK INSTALLATION ......... 10
15. SURGE TANK ORIENTATION -VENTILATION ... 11
16. ROCK COVER OF UNLINED WATER WAYS ....... 11
17. PENSTOCK SHAFT EXCAVATION .............. 12
18. ACCESS FOR SHAFT EXCAVATION ............ 13
19. PENSTOCK INTAKE WATER VELOCITy ......... 13
20. TIME FOR TAP BLAST ..................... 13
INGENIIZIR
t:HR.t=. laRI2INER R.Ei.
INTRODUCTION
The conference was attended by members of the OCE,
APA, NPA, NPD and Alaska District administration.
Following a welcome speech by Colonel Mathews,
Mr. Oppgave a orientation on the purpose of the
conference. Mr. Greely followed with a description
of the geological investigation carried out so far
for the project, and terminated with outlining the
plans for the immediate future. It was understood
that the present available topography of the lake
bottom in the possible tap area will be verified
by measurements from the ice covered lake this
winter, and that investigation by TV camera is also
considered. Along the power tunnel and the pressure
shaft alignment, further investigation will be
initiated the coming summer.
The meeting was then turned over to Mr. Gr¢ner.
As the advanced copy of the Lake Tap study had not
been received by the District, Mr. Gr¢ner went
through the study in some detail. In the discussion
following this introduction a number of questions
were asked. In the following these questions and the
answers are presented as well as memory permits.
- 1 -
1. The earthquake r{sk.
As outlined in section 1.11 of the study,any damage
to the power tunnel downstream of the gate shaft
can be repaired as long as gate operation is possible.
With the small percentage of the powertunnel length
upstream of the gate shaft the chances for seisnic
damage here seems remote.
With due consideration of the tap blast and the
joints and faults in this area the shaft location
could possibly be moved another 200 ft in the upstream
I
direction, thereby reducing the inaccessible tunnel
portion to approximately 600 ft.
After the plant is put in operation,repair work
in the tunnel section upstream of the gate shaft
would be practically impossible unless a solution
could be found for blocking the intake opening.
If damage occur at the intake opening itself,
underwater repair work would be extremely difficult
with a full power pool. A diversion tunnel at a
certain elevation could be the solution in sucn a
case.
- 2 -
2. Bulkhead at the intake opening.
A support structure for the combination trash rack -
bulkhead at the intake opening could be unpractical.
As the final blast will most probably have damaged
the rock structure surrounding the intake opening it
could be impossible within reasonable limits to
create the structural foundations required to resist
the full waterpressure possible with a closed bulk-
head. Foundation for the trash rack alone however
is relatively simpel to adjust to even an irregular
opening.
Should the rock structure surrounding the intake
opening prove relatively sound even after the final
blast a special solution could be tried. The solution
would require design of a trash rack and its
foundations to resist full waterpressure. In an
emergency the trash rack could then possibly be
blocked from the outside by divers installing
weighted wood planks over the trash rack. This
preliminary closure would hardly be as expenslve as
provisions for a permanent bulkhead.
Our conclusion is that provisions for a separat
bulkhead at the intake is hardly justified. We would
however recommend designing the trash rack and its
foundations for full water pressure if possible. An
emergency closure at this point could then be possible.
- 3 -
3. Lake Tap Alternative.
As outlined in the LQke tap study, section 1.03,
page 6, the conditions known at this stage about
the rock structure of the possible tap area do
not favour the alternative layout.
As indicated in the study we are further reasonably
convinced that a cost comparison, taking into account
the cost of the discharge tunnel and the other
elements required with the alternative,including
increased construction time, should not favour the
alternative.
4. Number of gates.
The power tunnel control structure should feature
two gates. The main regulation gate in the downstream
and the bulkhead gate in the upstream position.
With this arrangement the main gate can be serviced
or even removed for repair ones the bulkhead gate
is closed.
-4 -
INGENIIZIR
EHR.F=. EiRIZINER Ft.5.
5. Intake control structure.
As outlined in section 1.06, page 14 of the lake
tap study,we recommend using the bulkhead gate in
connection with the final blast. Using the bulkhead
in this connection saves time since the only other
possibi~ity would be a temporary concrete plug ln
the tunnel just downstream of the gate shaft.
Errection of this structure and removing same takes
time.
6. Adit to top of gate shaft.
On drawing 1551-101 of our study we suggest the
access adit to the top of ~he gate shaft and further
to the trash rack clea~ing station at Crater Lake
as a tunnel from the e~d of the proposed access road
to the area.
- 5 -
IN!§ENIIZIR
IR.F=. EiRIZINER! R.5.
7. Trash rack layout.
The intake trash rack lS discussed in section 1.07
of the lake tap study. In our opinion the final
selection of the arrangement should not be made
until the lake bottom surface between the tap point
and the cleaning station is definitely known.
In order to arrive at a solution in connection with
the question of a fixed against a movable Lrash rack,
a number of things must be considered.
First of all the type of debris possible ln the area
is a most important question, as equipment and
cleaning prosedures would be "depended on this. If
seasonal clogging with twigs and leaves is suspected
cleaning could possibly be scheduled for early spring
with the lake at its min. operating level. A fixed
trash rack could be the solution in this case, and
simpel cleaning equipment on a movable platform
lowered to the water surface could possibly be used.
However if cleaning for some reason should be required
at any time of the year, cleaning the rack with a
full power pool could favour a removable trash rack.
In this situation however the type of debris is again
important. One would for instance hardly attempt
to remove the trash rack if timber is suspected at
the intake opening.
- 6 -
INseNllZlR
E:HR.F.5RI2INER FtS.
With the information available at present a
definite recommendation is difficult. It would
in this connection be interesting to know what
the debris situation is like in Long Lake.
Observations here could possibly establish a
guide line for the solution at Crater Lake.
8. Tunnel lining to resist eartquake.
In section 1.05 of the lake tap study we basically
consider an unlined power tunnel for the Crater
Lake Project.
We assume that remedial treatment will be directed
towards leakage control and replacement of crushed
and faulty rock materials with dental concrete.
9. Discharge through surge tank access adit.
Using the alternative lake tap solution with diversion
through the access adit at the downstream end of the
powertunnel might for some projects be discussed.
On page 5 and 6 of section 1.03 of the lake tap
study we have outlined some of the conditions that
would favour the alternative. If discharge should
- 7 -
INSENIIZIR
-IR.F. EiRIZINER FI.S.
be considered for the entire length of the power tunnel
we consider the solution rather unpractical. The
amount of water involved would be considerable
with the discharge at the very downstream end of
the power tunnel. Discharging this to the area
above the power plant site, should result in
considerable damage to vegetation and possibly
to access roads etc. Although a separate discharge
tunnel would not be required,additional cost for
plugging the penstock intake and a second cleaning
of the invert of the powertunnel as far as the gate
shaft is required.
We would not recommend this arrangement.
10. Power tunnel alignment.
As mentioned in section 1.05 of the lake tap study
a change of tunnel alignment within reasonable
limits should not affect the overal conditions of
the project. Driving the power tunnel to intersect
faults and joints at a right angle is certainly
recommended.
- 8 -
t:HFii!. F= .IZINER Ft 5.
11. Blind tunnel orientation.
The blind tunnel of the lake tap arrangement can
be located to the right or left side of the power
tunnel. The most favourable :ocation should be
selected in accordance with the geological information
established through the power tunnel excavation.
The final decision in this respect need not be taken
until the power tunnel is excavated to the vicinity
of the downstream end of the lake tap arrangement.
As for the configuration of the final blast, this
should, because of the dept, be as regular and simpel
as possible.
12. Shock load on closed bulkhead.
Blasting the final pj.ug as recommended against an
air filled tunnel the shock load on the closed
bulkhead should not be severe. The gradual
compression of air in the tunnel, as the water is
entering , is further reducing the intencity of
the impact of water against the bulkhead.
An additional bubble curtain in front of the gate
would hardly be of practical value in this case.
However if shooting the final plug against a water
filled tunnel, a bubble curtain could be of value.
- 9 -
INSENIIZIR
HR_F.5RI'ZINER R.S.
13. Ventilation gdl:E:: shaf-:.
With a weT gate shaft a ventilation plpe from
downstream the control gate should extend vertically
for the height of the gate shaft.
With a dry gate shaft and the bonnet type gates, the
ventilation pipe could possibly be omitted.
We assume in this connection that the plant is only
operated with the gate fully open and that the gate
structure would tolerate the subatmospheric pressure
during the short opening and closing operatior..
14. Intake trash rack installation.
Timber entering the tunnel would hardly be a problem
in connection with the first drawdown. However as possible
saturat~d timber on the drained slopes of the lake
could dry out, this material could be floating as
the lake again fills up, and could give problems at
the following drawdown.
If the permanent trash rack for some reason can not
be installed following the first drawdown a preliminary
arrangement at least should be installed. At the next
drawdown the permanent structure should then be
errected.
-10 -
INISENIIZlR
t:HR.F. ISRIZINER F=I.S.
A full trash rack mig~t be installed for the initi2:
operation at the pens~ock intake if the turbine
manufacturer consider this necessary.
15. Surge tank orientation -ventilation
For technical reasons the surge tank could be an
inclined shaft and with rock structure allowing, the
top of the tank could be made to penetrate the hill
side·to give positive ventilation without an additional
ventilation tunnel.
Moving the tank location somewhat upstream to a
favourable rock structure could also be considered.
In order to arrive at the best solu~ion we feel that
a cost estimate comparing the vertical against the
sloping shaft, should be considered.
As for surge tank ventilation, omitting same ralses
a number of questions mostly in connection with
turbine regulation. T~e problem should in each case
be discussed with the turbine manufacturer considered.
16. Rock cover of unlined water ways :
The most recent development in Rock Mechanics suggest
that the rock cover of an unlined waterway with the
internal pressure equal to H, should be at least
0.6 x H at a point ho~isontally H feet closer to
.-11 -
INGENJIDR
the nearest surface than the tunnel. With reasonably
tight joints this is at present considered safe
regardless of the orientation of joints in the area
surrounding the tunnel.
Previously the cover suggested was 0.75 H to the
nearest surface, this however has proved to be
inadequate for certain joint orientations between the
tunnel and the surface. We would for Crater Lake
recommend following the most recent suggestion for
safe rock cover.
17. Penstock shaft excavation.
A number of questions in connection with shaft
excavation was discussed at the conference, and in
a general way other layouts were outlined.
We believe however tt.at the present layout shown
for the Crater Lake project with the steel liner
designed for full hy~rostatic pressure is the
most favourable solution in this case. Should
other solutions be ccnsidered for ~he penstock,
the layouts would have to be studied in some detail
in order to arrive at a possible conclusion.
-12 -
INSENIIZIR
CHR. F=. EiRIZINER FI.S.
18. Access for shaft excavation.
Using the present powerplant access tunnel in
connection with the shaft excavation should be possible.
With a tight wall errected against the power station
and running the station ventilation to create an over-
pressure In relation to the access tunnel in
question,the dust problem could possible be managed.
As for construction space requirements at the bottom
of the shaft we assume this should be no more of a
problem with the above solution than with a separate
access. We feel that a separate access tunnel to the
bottom of the shaft and around the station would be
rather expensive. A cost estimate comparing the
solutions could probably resolve the problem.
19. Penstock intake water velocity.
The water velocity through the rock trap upstream
of the penstock intake should be lower than the
velocity required to transport harmfuli rock debris
to the penstock intake. In your case we feel t~at
a velocity of around 2 ft/sec could be right.
-13 -
INseNIiZIR .
20. Time for tap blast.
The tap blast will normally be sheduled relatively
late in the construction periode. Before the tap is
attempted the power tu~nel inverT should be cleaned,
the gate shaft finished with the gates installed and
operational, the penstock steel liner should be
installed together with the power-house valve. The
valve should be operational.
The concrete plug with access door in the power tunnel
construction adit should be installed.
The powerplant errection work in connection with the
turbine and the generator etc. need not be finished
at the time of the tap blast.
In general construction work at a number of places
could be sheduled for the time following the tap blast.
Oslo, Febru y 1973.
~.WhY.
C. F. r¢ner
~. 14 -
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,
FEDERAL POWER CO~IIMISSION
REGiONAL OFF!CE
555 BATTERY STREET, ROOM 415
SAN FRANCISCO, CALIFo 94111
Gordon H. Fernald, Jr., Chief
Er.r;ineerinc; Division
North Pacific Division, Corps of Engineers
210 Custon House
Portland, Orecon 97209
Subject: Snettishem power values.
Dear ?-1r. Fernald:
Dec~ber IT, 1971
'We
I,
ReferrinG to your air l":'.:1il letter
have updated power values estirrdted
1971 cost levels with the following
of 24 Hovenbcr 1971 (HFDEil-HC) 1
for Snettisham Project to July
results:
Federal (3 1/3';~ interest)
( -~/)~. ) Federal ') j v,J interest
Pri vate (S-}r';, cost of money)
Capacity
Value
$I1~H-J'r
39 .. 99
46 .. 90
Energy
Value
rnills/kHh
9.91
9.91
9.91
'I~;cse vGlues nre l,uscd on cos ~s estir.:.:lted for an oil-fired, steam-
electric) ccneratirl{j plant assll.":ed to be located in the cutskirts of
Junc3u so tbnt no trGnsr::issicn is::'equired. Costs ,:ere estir.~;.ted on
the l:o:::'s 0~'" Gil ~~3S~: . .'_<~ c!:r.\.;.:.~l c~:;-~.;city· i'oc'"vc!,"' of' 5~/:, ~uut "'e t~l.ic\'c
thc-.:c rc~:..:..~ . .j"s C:::in 1:'2 t::( .. :1 rL.:JscY"i:,: ... ,ly C"l~2r D ru.;:~e oZ co}):!citJ ~"octcrG
vnr.r':' ;,~ .fr0.:: rcr'.C;l):O 3') > to ,') ;~. '.i.he value~i i:1clucie a h:,;d.ro-.;; ;;.ca;1
capacity Bdjustmcnt of plus 5%0
Other dct:::!!];; of' the alternative steam-electric plont cost cstimnte
is shm.;n in "the table attached.. F.ll"'ther im~orC'.ntion rec;arding the values
c;::1 b~ cU:.::";licd if r:c:c<cd.
Attechnent
Pro",dinj{ (or Tomorrow's GO,1/s"
1970
'i
!! "
United States De:partment of the Interi('lr
ALASKA POWER ADMINISTRATION
IN REPLY REFER TO:
600
AIRMAIL
District Engineer
Alaska District
Corps of Engineers
P. O. Box 7002
Anchorage, Alaska 99501
Reference: I~PAEN-Cw
Dear Sir:
P. o. BOX 50
JUNE;AU. A ... ASKA ggeOl
July 5, 1973
As requested by [llr. Weldon Opp of your office, we are fonvarding
five copies of our July 1973 load forecast showing the power and
energy requi rements for the Snettisham market area.
Tile requi rements fo 11 o\'Ji ng the anti ci pated power-on-l ine date
include project transmission system losses, station service, and
project power use, Transmission line losses are estimated at
6 percent of the n~rket area load. Station service is estimatea
at 75,000 K\,lh per month, or 1.000,000 klt/h per year, and project
use is estimated at 250,000 kwh per iiionth, or 3,000,OUO kwh per
year.
You wi11 note a suustantial increase in the Juneau area loa~ for
calellaar years 1974 and 'J975. This increase is due to the addition
of the Capitol Building, an Edght-story apartment building, an
eight-story Hilton hotel in lY74, and a new State Court Building
in 1975, all of which are under construction. These additions were
not considered in our January 1973 projection, but VJere mentioned
in our letter of September 1971. These extra loads are estimated
to have a peak demand of 4,30U h: and an energy requi rement at
18.~ million kwh per year, and are in addi~ion to the normal load
growth for the Juneau area. iwm,al load gl"owth is estir,lateu at
9 percent annually.
An additional factor justifyiing early availability of tt,e Crater
Lake unit is the effect of tile current natiom'Jide fuel problerri.
2
The local utili1::y is concerned clDI)ut possible fuel delivery curtail-
ment and cost increases. particul'lrly if Snettisham energy is
delayed or limited. Also, with tne possibility of fuel shortages
and pr; ce i licreases there could b= a move toward a ll-e 1 ectri c
installations or conversions not contemplated heretofore.
If you require additiona'j information, please feel free to call
on us.
Enclosures
Sincerely yours,
l (7)~ ( ,7/.' . U-e
// • V. Hp(As
~~ Acting Administrator
L/
POWER & ENlRGY REQUIREMENTS -SN~:TISHAM PROJECT -~ULY 1973 FORECAST
Fiscal Year Calendar Year
Energy t'1ergy Net Peak Load Factor
Year KWH X 1000 KWH X 1 ;JOO K~~ % --"---_._,-------------,----------
1 ~jbO
1951
1952
1953
1954
1955
1956
lY57 11 195b
1959
1960
1961
1962
1~63
1964
1965
1966
19U
I :.l6B
1969
197()
19;1
2/ 1972 II 1973
1974
1 ~75
1976
1 SJ77
1978
1979
is:0U
198'j
1982
1983
1984
b85
1986
1087
1%6
1989
1990
14,bUG
16,450
lS,S50
20,400
22,000
23,350
23,500
23,(300
25,400
27.800
30,700
3J,SOU
35,950
39,250
43,350
45,900
4B ,900
~1 ~ 'ISO
54~410
58 s 18U
62 sLUO
69 t 100
1'6,300
~6~SOO
121 j 5C 10
135 & ~){j()
148.700
162,000
17'! ,(jUG
1b6~J()Ll
208 DUGl)
227~(jLJ0
'1..47,OUO
269»GdO
293,000
319 ~ 'JUt)
34i t(ji.jJ
37:!. rlU,)ij
411 ,OOU
447,000
1/ Siil passed fo'r Statehood.
2/ Actual record.
H,,050
;;~522
17.364
1:),771
21 .10[,
,2,913
23,810
23,193
2/j. .40L
26,437
29,156
3:~ .282
3,~, 712
Jl D 150
i.] ,527
43,472
4<3,283
~,9 ,506
!)Z,791
56.029
6:) ,339
6~ ,600')
/l,76!"
7),500
1 '1 3 ,600
L: l ,3U\J
"i ~.~ :~ ~ ;j~.~ d
': 0) tOlL,
i 6,.) 1 DC; ')
1 :.'3 ~Oj
H,\GCU
;(, ] ,OIJ'J
~~'~ ,0(')
CJ, t ,J
2GJ ~uG\)
j;j),JCj
3~i~.UO'")
393 J Gl;~)
423.000
46) ,000
3,200
3.630
4.090
4,350
5,025
5,030
5,353
4,747
:),105
5,4fi5
5,837
7,150
7.0G6
9,O411,
9,424
10,003
10,859
10 9 510
11 .145
11 .820
13,0'lO
'14,420
1 J ~4GO
11 ,; 30
2,1.400
;:7 ,:J OU
30,400
33 s 000
36 (iOlj
,j:) I-
~,-'~ 7 ( "'i 't L jI; l \.)tJ
4 1),5:,;J
J\.J • 6;~;O
55) 2')0
60 ,100
65 • (~UO
71 • :.:::)<)
77 .l:JO
84,9C:0
92, ;)UO
10J .£:00
'II Snetti~,ham Project in operat'ion C.:tC;;J2f of C.Y. '19/3.
i.~-,(: -: el", 8stilijOtf'd a~' ,J, .. ,
50.1
48.S
48.5
51.9
48.0
52.0
50.S
54.7
54.6
55.2
57.0
47.6
56,0
46.9
50.3
49.5
50.S
53.8
54.5
54.1
52.9
51. i
50.4
53.0
53.0
53.0
53.0
53.0
53.0
03.0
SJ.O
53.0
53.0
53.0
53.0
53,0
53.0
53.0
53.0
53.0
53.0