HomeMy WebLinkAboutHydroelectric Power and Related Purposes for Valdez, Alaska 1978~~~ SOUTHCENTRAL RAILBELT AREA, .S/'
.. ALASKA
STAGE II CHECKPOINT REPORT
HYDROELECTRIC ·POWER·:&_ RELATED
PURPOSES for VALDEZ, ALASKA
2.182
LB PY ~
ALLISON LAKE
Prepared by the
Alaska District, Corps of Engineers
Department of the Army
April 1978
VAL
005
DATE ISSUED TO
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SOUTHCENTRAL RAILBELT AREA, ALASKA
STAGE II CHECKPOINT REPORT
HYDROELECTRIC POWER AND RELATED PURPOSES
FOR
VALDEZ, ALASKA
TABLE OF CONTENTS
Item
THE STUDY AND REPORT
Purpose and Authority
......___Scope of the Study
Study Participants and Coordination
The Report
Prior Studies and Reports
Study Area
RESOURCES OF THE STUDY AREA
General
Human Resources
NATURAL RESOURCES OF THE STUDY AREA
Introduction
Climate
Topography and Hydrology
Wildlife-Fisheries
Wildlife -Birds
Wildlife-Mammals
Agriculture and Range
Forestry
t-1i nera 1 s and Energy
PROJECTED ENERGY NEEDS
Introduction
Existing System and Demand
Projected Demand
PROBLEMS AND NEEDS
Local
Existing Facilities
Page
1
1
1
2
2
3
6
8
8
3
10
10
10
10
11
11
12
13
13
14
16
16
16
16
18
18
18
TABLE OF CONTENTS (cont)
Item
PLAN FORMULATION
Study Objectives
Possible Solutions
Alternative Sources of Power
Alternatives Selected for Further Study
Evaluation of Alternatives
THE SELECTED PLANS
Solomon Gulch
A 11 i son Creek
ECONOMICS OF THE SELECTED PLAN
Cost
Benefits
.Justification
SUMMARY
APPENDIX I
Section ----
A
B c
0
E
1:
G
H
Number
1
2
3
A-1
Item
Hydrology
Project Description and Cost Estimates
Power Studies and Economics
Analysis of Area Economy
Regional Geology
Environmental Assessment
Transmission Analysis
Power Market Analysis
List of Figures
Title
Location and Vicinity Map
Solomon Gulch
Al1 ison Creek
Location and Vicinity Map
19
19
20
21
26
26
32
32
32
34
34
34
35
36
25
33
33
A-3
TABLE OF CONTENTS (cont)
List of·Tables
Number Title Page
A-1 Lowe River and Solomon Gulch Streamflows A-15 A-2 Power Creek Streamflows A-16 A-3 Solomon and Lowe Correlation Equations A-17 A-4 Solomon Gulch Extended Streamflows A-18 A-5 Allison Creek Estimated Streamflows A-19 B-1 Solomon Gulch -Cost Estimate B-12 B-2 Allison Creek -Cost Estimate B-14 C-1 Anchorage Oil Prices C-14 C-2 FPC Table 8-1. Solomon Gulch C-23
List of Gra2hs
Number Title Page
A-1 Solomon Gulch Frequency Curve A-20
A-2 Lowe River Frequency Curve A-21
A-3 Power Creek Frequency Curve A-22
C-1 Projected Valdez Energy Demand C-21
C-2 Projected Total Valdez and Glennallen
Energy Demand C-22
List of Plates
Number Title Page
1 Solomon Gulch -Plan View B-16
2 Solomon Gulch -Dam B-17
3 Solomon Gulch -Penstock Profile B-18
4 Allison Creek-Lake Tap B-19
5 Allison Creek -Plan View B-20
THE STUDY AND REPORT
PURPOSE AND AUTHORITY
Due to the continuing rapid population growth in the southcentral · ·
railbelt area of Alaska and because of the increasing national concern
over the need to conserve the nation's nonrenewable energy resources~
the Committee on Public Works of the United States Senate adopted a
resolution on 18 January 1972 requesting a review of the feasibility
of providing hydropower to the southcentral railbelt area. The resolu-
tion is quoted as follows:
"That the Board of Engineers for Rivers and Harbors
created under the provisions of Section 3 of the River
and Harbor Act approved June 13, 1902~ be, and is
hereby requested to review the reports of the Chief
of Engineers on: Cook Inlet and Tributaries, Alaska,
published as House Document Number 34, Eighty-fifth
Congress; Copper River and Gulf Coast, Alaska, pub-
lished as House Document Number 182, Eighty-third
Congress; Tanana River Basin. Alaska, published as
House Document Number 137, Eighty-fourth Congress;
Yukon and Kuskokwim River Basins, Alaska, published
as House Document Number 218, Eighty-eighth Congress;
and other pertinent reports with a view to determining
whether any modifications of the recommendations con-
tained therein are advisable at the present time,
with particular reference to the Susitna River hydro-
electric power development system, including the
Devil Canyon Project and any competitive alternatives
thereto, for the provision of power to the Southcentral
Railbelt area of Alaska."
The study of the Valdez area resulted from a city request in 1976
and a determination that this area could be considered within the
general southcentral railbelt authority.
Plan formulation will be based on existing national policy and will
give full consideration to the economic, social, and environmental con-
cerns of the public, in order that any recommended plan will insure the
maximum sustained public benefit from the use of water resources of
the region.
SCOPE OF THE STUDY
This report is the Stage II Checkpoint Report. The study is a
systematic examination of the economic, social, and environmental
conditions of the Valdez study area as they relate to electrical
energy needs and hydroelectric and related water resource potential.
It embodies the concepts of multiobjective planning in accordance with
the directives and guidance provided by the National Environmental
Policy Act of 1969 (NEPA), Section 122 of the River and Harbor and
Flood Control Act of 1970, and the Principles and Standards for Plan-
ning Water and Related Land Resources, promulgated by the Water
Resource Council in 1973. The preliminary findings are summarized
and an evaluation of possible electric power generation alternatives
is presented along with two marginally feasible plans for the Valdez
study area. Investigations and coordination relative to this study
were made in sufficient detail to permit the identification of public
needs, an assessment of existing and probable future conditions and
resource capabilities, the establishment of specific planning objec-
tives, and the formulation of plans which represents the best possible
response to the study authority and planning objectives.
STUDY PARTICIPANTS AND COORDINATION
The Corps of Engineers has primary responsibility for conducting
the study, consolidating information from other agencies, formulating
the plans, and preparing the report. The Alaska Power Administration
will have the responsibility of preparing analyses on the marketability
of power in the railbelt. Other Federal, State, and local agencies
providing advice and information include, but were not limited to:
Federal Power Commission, U.S. Bureau of Reclamation, Bureau of
Land Management, Fish and Wildlife Service, Environmental Protection
Agency, National Marine Fisheries Service, Soil Conservation Service,
Alaska State Clearinghouse, Alaska Department of Fish and Game, Depart-
ment of Community and Regional Affairs, U.S. Geological Survey, National
Weather Service, Alaska Conservation Society, Chugach Natives and
Copper Valley Electric Association (CVEA).
THE REPORT
The Plan of Study (POS) has outlined the overall study and provided
a useful management tool. The Stage II Checkpoint Report on the Valdez
hydropower study will continue with the four planning tasks; problem
identification, formulation of alternatives, impact assessment, and
evaluation. The study is an examination of the technical, economic,
social, and environmental conditions of the Valdez, Alaska electric
power market area as related to electrical energy needs and resources.
This main report will summarize the technical appendix and indicate
whether there is a feasible project within the study area.
2
PRIOR STUDIES AND REPORTS
Corps of Engineers Reports:
1. Cook Inlet and Tributaries, Alaska, HD 34, 85th Congress
The Chief of Engineers recommended construction of sma.ll boat
basins at Seldovia; at the end of Homer Spit; and at Ninilchik;
improvement of the harbor at Anchorage; and the stabilization of
about 1,500 feet of riverbank by rock revetment along the Talkeetna
River to protect the town of Talkeetna from flood damage.
2. Cooper River and Gulf Coast, Alaska, HD 182 83d Congress
The Chief of Engineers recommended improved protection for small
boat harbors at Seward and Valdez. The Secretary of the Interior in
his report stated that no market was available for use of potential
power development.
3. Tanana River Basin, Alaska, HD 137, 84th Congress
The Chief of Engineers recommended the improvement of Chena and
Tanana Rivers, to provide for a diversion dam and control structure
across Chena River, a diversion channel from Chena River to Tanana
River, a levee, and necessary drainage facilities.
4. Yukon and Kuskokwim River Basins, Alaska, HD 218 88th Congress
The Chief of Engineers recommended that no project be adopted at
this time for improvement of the Yukon and Kuskokwim Rivers for navi-
gation and flood control. He recommended further that the report of
the District Engineer be adopted as a guide for further investigations
of water resource developments in the Yukon and Kuskokwim River basins
as economic conditions warrant.
5. Review of Interim Report No. 2, Cook Inlet and Tributaries,
Part No. 1, Hydroelectric Power, Bradley Lake, HD 455, 87th Congress,
2d Session.
The Chief of Engineers recommended the construction of a dam and
reservoir at Bradley Lake, with a power-generating plant on Kachemak
Bay and appurtenant power facilities.
6. Mineral Creek Townsite, City of Valdez, Alaska To: U.S. Army
Corps of Engineers, Alaska District by Shannon & Wilson Inc., 28 August
1964
3
The conclusions indicated that the site for the new town would
have an adequate foundation which would be stable under normal con-
dions and earthquake situations.
7. Rampart Canyon Project, Volumes I and II, 1971
The Alaska District Engineer recommended that a project for hydro-
electric power generation at the Rampart Canyon site on the Yukon River
not be undertaken at this time because of marginal feasibility and of
environmental and ecological problems.
The Alaska District Engineer recommended construction of the Susitna
River project consisting of a combination of two dams and reservoirs
designated as Watana and Devil Canyon on the upper Susitna River, Alaska.
9. Flood Plain Information, Mineral Creek, Valdez, Alaska, Army
Corps of Engineers, Alaska District, July 1976
The report is an informative document which delineates the 100 and
500 year flood plains and alerts the general public to the flood hazard
potential.
Department of the Interior Reports:
1. U.S. Bureau of Reclamation, A Reconnaissance Report on the
Potential Development of Water Resources in the Territory of Alaska,
December 1948
This report described the resources of the Territory of Alaska and
indicated potential for power development at 72 sites. The territory
was divided into five regions and potential hydropower sites were
studied, of which five were in the Susitna River basin.
2. U.S. Bureau of Reclamation, A ReGort on Potential Develo~ment
of Water Resources in the Susitna Riverasin of Alaska, August952
This report described the resources and potentialities of the
Susitna River basin. An ultimate plan of development of hydropower
resources for the basin were described, and included 12 major dams. In
the ultimate plan, the total powerplant capacity will be 1.249 million
kilowatts, and will provide firm annual energy of 6.18 billion kilowatts-
hours. Total reservoir capacity will be 22.69 million acre-feet.
4
3. U.S. Bureau of Reclamation, Devil Canyon Project, Alaska,
March 1961
The Commissioner of Reclamation recommended the proposed Devil
Canyon project, which consisted of two major dams and reservoirs on
the upper Susitna River, a powerplant, and transmission lines and
appurtenant facilities to deliver power and energy to Fairbanks and
Anchorage. The largest structure would be the Devil Canyon Dam which
would possess many advantages for development of hydroelectric power;
however, storage capacity was not adequate. Therefore, a second dam
at the Denali site was proposed, where a larger reservoir could be
created with a low earthfill dam. Based on the hydrologic data avail-
able at the time of the report, the estimated energy potential of the
system which consisted ultimately of four dams with first-stage develop-
ment of Devil Canyon and Denali were 7.0 and 2.9 billion kilowatt-hours,
respectively.
4. Alaska Power Administration, Devil Canyon Status Report,
May 1974
This report was a partial update of the t·1arch 1961 report of the
U.S. Bureau of Reclamation on the Devil Canyon project. This report
included updating the designs for the project features, preparation of
new cost estimates, and brief analysis of power market, environmental,
and economic aspects.
5. Alaska Power Administration, 1974 Alaska Power Survey, pre-
pared for the Federal Power Commission in rive volumes
The report included information and data on resources and electric
power generation, economic analysis, load projections, environmental
considerations, and consumer affairs.
Private Enter~rise:
1. A Reassessment Report on Upper Susitna River Hydroelectric
Development ror the State of Alaska, September 1974, by the Henry J.
Kaiser Company. The company was considering the development of a large
aluminum plant within the railbelt area contingent upon availability of
large quantities of inexpensive energy. To meet this demand, Kaiser
suggested a first-stage upper Susitna River development consisting of a
single high dam (termed 11 Devil Canyon High 11 and/or "Susitna r· in this
report) 5 miles upstream from the USBR Devil Canyon damsite. Subsequent
development would include power projects both up and downstream for the
high dam.
2. Solomon Gulch H droelectric Pro'ect, FPC Project No. 2742, by
Copper Valley E ectr1c ssoc1at1on, nc., prepared by Robert W.
Retherford & Associates, March 1975, revised February 1976, updated
November 1976.
5
Other:
Solomon Gulch Project, Draft Environmental Impact Statement, Federal
Power Commission, July 1977.
STUDY AREA
As indicated by the directive of Congress, the study area encom-
passes the entire southcentral railbelt which is comprised of three
subregions: Cook Inlet subregion, Gulf of Alaska subregion, and the
Tanana subregion. These areas contain Alaska's largest concentration
of population and economic activity. The Gulf of Alaska subregion
encompasses the Valdez area and the communities of Glennallen and
Cordova.
The community of Valdez was established in 1890 as a debarkation
point for men seeking a route to Interior Alaska and the Klondike gold
fields. A post office was established in the community in 1899, and
Valdez soon became a supply center for gold and copper mining in the
immediate area.
The city is in a setting of natural beauty situated in mountainous
terrain at the head of Port Valdez. It is the farthest north ice-free
seaport in Alaska and serves as southern terminus of both the Trans-
Alaska Oil Pipeline and the Richardson Highway. Unlike the other port
communities of Anchorage, Seward, and Whittier, Valdez is not served by
the Alaska Railroad, and is only linked to the interior by road and air.
Although served by air, road, and sea, Valdez is relatively isolated
from other population centers in southcentral Alaska. Anchorage is
located 115 miles to the west, but physical barriers increase the dis-
tance by highway to 306 miles.
Old Valdez was destroyed by the 1964 Alaska Earthquake and result-
ant siesmic wave. The new relocated townsite near Mineral Creek has
been growing rapidly, especially with the Trans-Alaska Pipeline Terminal
being located in Port Valdez. The population in Valdez was 1,823 in
1975 and 8,253 in 1977. According to the Valdez Comprehensive Develop-
ment Plan, (Bomhoff, Collie & Klotz, 1971) the 1991 population projec-
tion for Valdez is 15,000.
Port Valdez is the northeastern most extension of Prince William
Sound and is surrounded by steep walls of the Chugach Mountains. It is
a 3 mile wide, steep walled, glaciated fiord that extends east-west
about 14 miles. At its western end the fiord bends to the southwest
and necks down to a mile in width at Valdez Narrows before it opens out
into the Valdez Arm of Prince William Sound. The steep mountain slopes
6
extend beneath the water forming a steep-sided, flat bottomed trough
400 to 800 feet deep. The shore of Port Valdez is steep and rocky
except where river deltas and glacial moraines have intruded into the
fiord.
Valdez is called the "Switzerland of Alaska" and has a busy tourist
trade. Fishing, canning, and the pipeline terminal also contribute
substantially to the local economy and indicate a bright economic future
for Valdez.
The cities of Cordova and Glennallen may also be considered within
the study area if a transmission line could be economically justified.
Cordova is a rural Alaskan community located on Orca Inlet and only has
sea and air transporation. The lack of a road interconnected with the
State of Alaska road system could be attributed to the variable terrain
in that area. Glennallen is another rural Alaskan community which is
located about 110 miles from Valdez adjacent to the Glenn Highway.
7
RESOURCES OF THE STUDY AREA
GENERAL
The economy of the Valdez area is based upon its human and natural
resources. The decision to make Valdez the ocean terminal for the Trans-
Alaska Oil Pipeline transformed a quiet little village into a beehive
of activity as the area became a key base of operations for the .Alyeska
construction crews, the oil storage yard, and eventually the tanker
loading terminal.
For many years fishing, mining, and freighting were the major indus-
tries of the area with long range plans to connect the cities of Valdez
and Cordova by the Copper River highway. The earthquake of 1964 and
the accompanying siesmic waves caused sufficient damage to the old city
and water front facilities to bring about a move to the present town
site. The development of the present water front facilities, capable
of handling 120 fishing boats, freighters, and ferry boats were com-
pleted during 1975 and 1976. The completion of the pipeline and port
facilities will mean one more adjustment for Valdez as they go from a
crash construction program to normal operation of the oil terminal.
HUMAN RESOURCES
In 1975 the population of Valdez was just under 2,000. The move to
the new city site was well underway and major adjustments were being
made to meet the impact of pipeline development. In 1976 the population
was 6,670 and the peak of construction activity in late 1976 and early
1977 would see 8,253 people living, working, and looking for work in a
town that had been less than 2,000 a few years before. The following
table shows the population and employment picture of Valdez through the
peak periods of pipeline construction and the adjustment period as of
January 1978. It must be kept in mind that current total population
estimates are probably on the high side and that many people previously
in the labor force are still making preparations to leave or may be
waiting to see what the proposed gasline may offer.
8
Category
Ag. Fishing
Construction
Local
Pipeline
Trades
Prof.
Fin, Ins,
Acct.
Gov.
Mining
Manufacturing
Services
Trades
Trans & Comm.
Total Emp.
Total Unemp.
Total Labor
Other
Population
VALDEZ POPULATION AND EMPLOYMENT
1976
Number %
10 -less than
150 -
2,730 -
280 -
100 -
340 -
5 -
75 -
130 -
90 -
130 -
3.71
67.60
7.0
2.46
8.42
less than 1
1.86
3.22
2.23
3.22
4,040 -100.00
760 -16
4,800 -
1,870
6,670
1977
Number %
12 -less than
186
3,380
350
123
421
8 -
93 -
161 -
112 -
161 -
3.7
67.60
7.0
2.5
8.40
less than 1
1.86
3.22
2.23
3.22
5,000 -100.00
952 16
5,952
2,300
8,253
January 1978
Number %
30
150
120
205
45
444
35
130
140
150
1 ,449
458
1 ,907
5,576
7,483
2.07
10.35
8.28
14.15
3.11
30.64
2.42
8.97
9.66
10.35
100.00
24
(est)
(est)
Long range (1990) population estimates for Valdez vary from 10 to
14,000 depending on such things as future pipeline routes and use of the
State's royalty gas and oil. One thing is certain, the Valdez economy
is now an oil-based economy and will continue to be through the fore-
seeable future.
9
NATURAL RESOURCES OF THE STUDY AREA
INTRODUCTION
The southcentral railbelt area as indicated previously is comprised
of the Cook Inlet, Gulf of Alaska, and Tanana subregions. The following
discussions of the Gulf of Alaska subregion and its economy is designed
to provide information on which to base judgements as to the water
resource development needs and impacts of any proposed solutions in
that area. (Most of the information in this section of the report has
been taken from Resources of Alaska compiled in July 1974 by the Resource
Planning Team of the Joint Federal-State Land Use Planning Commission
for Alaska. It is the most comprehensive and up-to-date compendium of
resource information for the study area.)
CLIMATE
Inland of the Chugach Mountains is an area characterized by a semi-
arid climate with relatively clear skies and extreme temperatures. The
mean annual temperature is generally about 29° F. The southern flank
of these mountains is somewhat warmer. The first freeze in the fall
occurs about 14 September, and the last freeze in the spring usually
occurs about 24 May, giving an annual average of about 110 frost-free
days. Precipitation varies widely, as demonstrated by annual averages
of 60 inches at Valdez, and 80 inches at Cordova, with 100 to 300 per-
cent more precipitation in the mountains than in the lowlands. Earth
tremors are common, especially along the southern portion of this sub-
region.
TOPOGRAPHY AND HYDROLOGY
This subregion includes parts of the Alaska Range, the Wrangell and
Chugach-Kenai Mountains, and the Copper River lowland. Massive moun-
tains, rising in altitude to more than 16,000 feet in the Wrangells
support the largest ice fields and glaciers in North America.
Principal water shed of the subregion is the Copper River system
with a 24,400-square-mile drainage area. It drains the south slopes of
the Alaska Range, south and west slopes of the Wrangell Mountains, most
of the Chugach Mountains, the Copper River Basin, and a small section
of the Talkeetna Mountains. The land surface is largely rough and
mountainous, with a narrow coastal plain along the gulf and broad lake
basin in the Gulkana area between the mountain systems.
The coastal portion of the subregion is generally free of perma-
frost, while the interior portion is underlain by discontinuous perma-
frost. Glaciers cover most of the higher peaks in the Wrangell Mountains
and nearly all of the crest of the Kenai-Chugach Mountains, which
separate the coastal area from the interior.
10
r~ost of the larger communities in this subregion are accessible by
road. A notable exception is Cordova. Whittier is linked to Portage
by rail and to Valdez by ferry.
WILDLIFE -FISHERIES
Since much of this subregion is mountainous, the fisheries habitat
is characterized by many short, steep coastal streams and the rather
large drainage of the Copper River. The entire mountainous area is
heavily glaciated, and many of the streams carry a high load of glacial
sediment. There is a paucity of lakes, for such a large area.
Pink and chum salmon utilize the short coastal streams. Silver
salmon spawn and their fry develop in somewhat larger streams where the
young can survive for at least 1 year. Red salmon are found primarily
in drainages that contain a lake or lakes, such as the many lakes of the
Copper drainage. King salmon spawn in the upper reaches of the Copper
River drainage. Dolly Varden are present throughout the coastal stream
system. Arctic grayling are confined to the clearwater systems in the
upper portion of the Copper River drainage and have been successfully
introduced in the Cordova area. Rainbow trout are present, as well as
lake trout, whitefish, and burbot.
Important marine fish and shellfish are herring, halibut, red snapper,
black cod, king crab, tanner and Dungeness crab, shrimp, scallops, and
razor clams.
The most sought after sport fish are the five species of Pacific
salmon, Dolly Varden, rainbow trout, Arctic grayling, lake trout, and
burbot.
WILDLIFE -BIRDS
Prince vJilliam Sound is an important migration route for many species
of waterfowl.
The Copper River Delta and the Bering Glacier outwash plain contain
about 15 to 18 townships of exceptional value to waterfowl. This region
is the principal nesting area for the world's population of dusky Canada
geese, and may produce more ducks per square mile than any other known
area in Alaska except Yukon Flats. Trumpeter swans reach their greatest
densities here. In spite of its unique nesting population, the delta is
probably most important as a staging and feeding area for migratory fowl
bound to and from the arctic and subarctic nesting areas to the north.
At the confluence of the Bremner and Copper Rivers, 40 miles from
the mouth of the latter, are several townships of trumpeter swan habitat
second only to the Copper River delta in importance.
11
The entire coastal area is habitat for seabirds of various species.
At least 48 major seabird colonies have been identified in this sub-
region, and undoubtedly many more exist.
The nearly 200 square miles of tidal flats in Orca Inlet and the
Copper River Delta probably support one of the greatest remaining con-
centrations of birdlife in existence.
Resident game birds of forest, treeless, and other habitates are
spruce, ruffled, and sharp-tatled grouse; willow, rock, and white-tailed
ptarmigan.
WILDLIFE -MM1MALS
Black bears live throughout the subregion. Population varies from
relatively high levels along the coastal areas to moderate levels in
the interior areas.
Brown/grizzly beast are found throughout the subregion; the bears
are less common on the west side of Prince William Sound than on the
east. They are more numerous in the interior than along the coast.
Wolves are relatively abundant in the interior portions of the sub-
region, but quite scarce along the Prince William Sound coast. The
interior population numbers about 300.
Wolverines are abundant in the interior, but not as common along
the coast.
Sitka black-tailed deer are primarily confined to islands of Prince
William Sound, but some occur on the mainland in the Cordova area.
Barren ground caribou inhabit the interior portion of the subregion,
which contains a sizable amount of the Nelchina caribou herd's winter
range.
Two disti~ct bison herds, the Chitina and Copper River, exist in the
subregion.
Some of the most important Dall sheep range in the State is contained
in this subregion.
Moose occur in greatest concentrations in the interior portions of
the subregion, but have suffered a severe decline in recent years.
Mountain goats are abundant in the mountains of Prince William Sound,
but present only in low numbers in the Wrangell Mountains and interior
portions of the Chugach Mountains.
12
After being nearly wiped out in the 19th century, sea otters have
made an amazing recovery. There are now about 6,000 in the Gulf of
Alaska. Harbor seal, Steller sea lion, and various whales are in the
Gulf.
Other smaller mammals present include lynx, red fox, land otter,
mink, marten, short-tailed weasel, beaver, muskrat, and snowshoe hare.
AGRICULTURE AND RANGE
Potential agricultural and range resouces of the subregion are mainly
along the Copper and Chitina River valleys. Narrow coastal strips and
stream deltas along the coast might be grazed during the summers, with
removal of the animals imperative for the balance of the year.
Climate of the interior is continental in nature with warm summers
and cold winters. Elevation is generally 1,000 feet or more. The area
lies in the 11 rain shadow 11 of high coastal mountains, and summer precipi-
tation is typically below 10 inches. The proximity of very high moun-
tains and downward flows of cold air combines to render the area suscep-
tible to summer frosts and limits reliable agricultural production to
gardens and forage crops.
In its natural forested state, the lower land has relatively little
range forage value.
FORESTRY
The interior forest of three different forest systems covers a total
of 4,998,000 acres. The bottom land spruce-poplar forest ecosystem,
303,000 acres, it located primarily in the Copper and Chitina River
valleys and can be considered essentially commercial forest land. The
upland spruce-harwood forest covers 2,211,000 acres and has local stand
of commercial spruce and hardwoods.
Most of the forest stand in this ecosystem are noncommercial because
of their slow growth due to poor site conditions. The lowland spruce-
hardwood ecosystem covers 2,484,000 acres and is noncommercial throughout.
The best timber production land is in Native village withdrawals and
Native regional deficiency areas. The major acreage of forested land
lies in Federal control.
Two forest inventories were conducted in the subregion; an extensive
inventory covering the entire basin, and a relatively intensive inven-
tory covering the better bottom land forests. The following data are
taken from the basin-wide inventory which lists 4,431,000 acres of total
13
forest land for the Copper River basin which 1,178,000 acrea are commer-
cial and subcommerical timber and 3,253,000 acreas are noncommerical.
Of the 2,064,000 acres of coastal forest, about 901,000 acres are con-
side red commercia 1 and subcommerci·a 1.
Total standing volume in the interior forests is 1.5 billion board
feet (International 1/4 inch rule) consisting of 1.4 billion board feet
of spruce and 52.5 million board feet of hardwoods, half of which is
birch. Average volume per acre is 1,240 board feet and total annual
volume growth is 28.5 million board feet. This volume can be considered
the potential sustained yield for the entire Copper River basin.
The total volume of the coastal forests is about 19.8 billion board
feet (International 1/4 inch rule), 67 percent of which is Sitka spruce
and 28 percent is western hemlock. The potential annual harvest on the
Chugach National Forest lands is 103 million board feet (International
l/4 inch rule) plus an additional 20 million board feet from other lands.
Regeneration in both coastal and interior forest systems appears to
be adequate but could be improved with higher stocking density. Rotation
ages for the interior forests are about 100 to 120 years and 70 to 210
years in the coastal type.
Several sawmills operate in the subregion, some sporadically and
others, like the mills at Seward and Whittier, on a full-time basis.
The mills produce a variety of products for local markets and cants for
export to Japan.
MINERALS AND ENERGY
High oil and gas potential exists in the coastal section within the
Gulf of Alaska province. The many oil and gas seeps and petroliferous
beds in sedimentary rocks, which exceed 25,000 feet in thickness, have
attracted intensive exploration by industry. Interest has now shifted
to the Outer Continental Shelf where the presence of many folds, the
possibility of reservoir rocks, and lack of intense deformation indicate
high possibilities of petroleum deposits. The Copper River lowlands have
low to moderate oil potential.
Coal-bearing rocks have been mapped over 50 square miles near the
Bering and Kushtaka Lakes in the Bering River coal field. Similar rocks
appear in the Robinson Mountains east of Bering Glacier. The coal ranges
upward from low volatile bituminous in the southwestern part. The beds
are a few feet to 60 feet thick. The coal in part of the field has
coking properties.
Geothermal energy potential is high. The Wrangell Mountains are
the site of recent volcanic activity and provide a favorable environ-
ment for heat reservoirs.
14
Some potential for cement may exist in the limestone beds exposed
near McCarthy. The beds are several hundred feet thick and quite
extensive.
Sand and gravel deposits of economic significance occur in the
Copper River lowlands, the Chitina Valley, and adjacent tributaries.
Metallic minerals occur in several districts. Lodes in many parts
of the Copper River region contain copper, gold, silver, molybdenum,
antimony, nickel, iron, lead, and zinc, but only gold, copper, and
byproduct silver were mined commercially. The Kennicott mines near
McCarthy, and mines in the southweastern and northeastern parts of
Prince William Sound, accounted for most of the 690,000 short tons of
copper produced in Alaska. Two or three million dollars worth of gold
and silver were produced from lodes and as byproducts of copper mining
in the Prince William Sound district. Gold placer deposits produced
35,000 ounces of gold and a few ounces of platinum from the Chistochina,
Slana, and Nizina districts.
Gold and copper lodes are in the Seward district and eastern part
of the Kenai Peninsula. Copper, gold, silver, and molybdenum lodes are
between the Chitina River and the crest of the Wrangell Mountains.
Other mineralized sites occur throughout the subregion.
15
PROJECTED ENERGY NEEDS
INTRODUCTION
The feasibility study wi11 be a more comprehensive analysis in which
the Alaska Power Administration will develop the projected energy needs
of the study area. Previous reports have been utilized to obtain an
estimate of the future energy needs in this report.
The only producer of electrical power for the public in the Valdez
area is Copper Valley Electric Association (CVEA). CVEA is a distribu-
tion type Rural Electric Association (REA} which generates all of its
power requirement for Valdez from diesel units and a gas turbine. The
Valdez system came into existence following the 27 March 1964 earthquake,
which demolished the town. Studies following the quake determined that
the townsite should be abandoned. A new Valdez was built at a location
approximately 5 miles west of the original townsite.
EXISTING SYSTEM AND DEMAND
The Valdez system presently serves approximately 1,400 consumer units
over about 25 miles of distribution lines. The system serves the new
city of Valdez, the old Valdez area and consumers from old Valdez to
the airport area, and 10 miles east of old Valdez along the Richardson
Highway. The energy produced from 1973 to 1976 is shown below.
Years ~ H
1973 6,470
1974 9,460
1975 18,250
1976 26,000
The monthly distribution of energy is shown in the Appendix, Section
C, Power Studies and Economics, along with other pertinent data.
PROJECTED DEMAND
The most recent estimate of utility loads is in the study prepared
for CVEA. 1/ The impact of the pipeline in the area has continued to
increase the demand for additional energy. The following is the pro-
jection from the study mentioned above.
l/ Copper Valley Electric Association, Inc. 15 Year Power Cost Study,
Robert W. Retherford Associates, November 1976
16
Demand KW
Energy MWH
1980
5,800
27,900
.1985
8,600
41,400
1990
12,800
61,400
The current trend in demand indicates a rapid rate of growth even
after the majority of the pipeline construction was finished. It seems
that the projected figure for 1980 of 27,900 MWH of energy may be attained
earlier than projected. The subsequent figures would also probably be
reached earlier which only reinforces the need for additional energy in
the Valdez area.
17
PROBLEMS AND NEEDS
LOCAL NEEDS
The local public initiated the study because they felt there might
not be enough power to supply the Valdez area in the near future. The
impact of the Trans-Alaska Pipeline has stimulated growth in the study
area and its impact will continue to be felt for some years.
The past, present, and future developments encouraged the local
officials to approach their Congressional officials to have the Valdez
power potential evaluated. They also expressed an interest in the
possible development of additional municipal water storage. At the
present time the city of Valdez has three wells which comprise the
municipal water supply.
The resource management needs are the problems posed by the local
community along with the problems that are traditionally addressed.
Therefore, in addition to studying needs for electrical power and munici-
pal water supply, the Corps will also evaluate other purposes such as
flood control, recreation, and fish and wildlife enhancement. Some of
the alternatives may be able to utilize these purposes and others may
not, depending upon location and other factors. In consonance with any
new development in the community, it is their desire to preserve and
maintain the 11 Alaskan way-of-life.11 Besides the local needs, there is
national policy to conserve nonrenewable resources which will aid in
achieving energy independence from foreign sources.
EXISTING FACILITIES
The only public electric utility in Valdez is Copper Valley Electric
Association (CVEA). At present, CVEA has a total installed capacity of
10,113 kilowatts (kW), and their projected energy demand for 1977 is
27,000 megawatt hours {MWH). Most of this energy is produced by diesel
fired generators along with a gas turbine, thus utilizing a nonrenewable
resource. Copper Valley Electric Association has a permit pending with
the Federal Power Commission {FPC) to develop the Solomon Gulch Hydro-
electric Project. The only other existing source of energy in the Valdez
area is at the Trans-Alaska Pipeline Terminal, which has its own gener-
ating facilities with a total of 37.5 MW of installed capacity. None
of this energy or capacity is available to the local community.
18
PLAN FORMULATION
Plan formulation involves a systematic process of.analyzing needs
and problems, establishing study objectives, and developing and evalu-
ating alternative plans for resource management. Plan formulation is
guided by Corps of Engineers policy on multiobjective planning, in
accordance with legislative and executive authorittes provided by the
National Environmental Policy Act (NEPA), Public Law 91-190, 1 January
1970; Section 122, Rivet and Harbor and Flood Control Act of 1970,
Public Law 91-611, 31 December 1970; Principles and Standards for
Planning Water and Related Land Resources, Water Resources Council,
38 FR 24778-24869, 10 September 1973; and various other statutes. Under
these guidelines, the basic water resource planning objectives are,
coequally, National Economic Development (NED) and Environmental Quality
(EQ), with consideration being given to social well-being and regional
development.
STUDY OBJECTIVES
The study objectives are derived from the problems and needs that
are specific to the study area and can be reasonably addressed within
the framework of the study authority and purpose. The objectives
selected for this study are:
1. Identify the present and future need for power in the Valdez
area.
2. Assess the possibilities of providing additional energy for the
Glennallen and Cordova areas via an overland transmission line.
3. Assess the feasibility of different energy alternatives in the
study area.
4. Evaluate the alternative hydropower sites utilizing them as multi-
purpose projects taking into account the possible purposes of power
generation, flood control, recreation, and other types of usage such as
water supply where applicable.
5. Identify the various social, economic, and environmental impacts
that could be caused by the different types of development in the Valdez
area.
6. Minimize the effects of the impacts, mitigate damages where
possible and attempt to enhance the environmental quality of the area.
7. To conserve nonrenewable resources of the nation and to contrib-
ute toward national energy independence. ·
19
To preserve the Alaskan lifestyle by halting growth of all forms
at the present level is beyond the authority of the Corps of Engineers
and is thus not a study objective.
POSSIBLE SOLUTIONS
The following alternative methods of satisfying the primary study
objective, the provision of electric power for the Valdez area, were
considered as possible solutions:
Alternative Sources of Power
No growth
Coal
Natural gas and oil
Nuclear
Geothermal
Solar
Wind and tide
Wood
lntertie with sources elsewhere
Solid waste
Hydroelectric
Hydroelectric Alternatives
Solomon Gulch
Allison Creek
Mineral Creek
Unnamed Creek
Lowe River
These alternatives were screened on the basis of preliminary estimates
of response to the basic water resource planning objectives of NED
(economic viability) and EQ (contributions to environmental quality).
Within the NED considerations, in addition to the purely economic factors,
such items as technical feasibility (can it be done with existing tech-
nology?) and scale (does it do too little or too much?) were considered
important. Within the EQ considerations, in addition to positive con-
tributions to environmental factors, a lack of adverse effects was con-
sidered significant. The intent and effect of this brief screening was
to rule out impracticable and marginal alternatives leaving a small
number of the better possible solutions to be studied and evaluated in
detail. The following discussions summarize the preliminary evaluation.
20
ALTERNATIVE SOURCES OF POWER
No Grm'/th:
Restricting the growth in power demand and altering energy pr1c1ng
policies are political decisions that cannot be addressed in this report
with any authority. However, any adopted policy significantly reducing
industrial consumption of energy would have to consider the living
standard which to a large extent depends on energy consumption. It
would also be necessary for a policy to restrict population growth and
to apply to all forms of energy to be effective. This alternative would
achieve the maximum possible conservation of nonrenewable resources and
have minimal adverse environmental impacts. However, in the presence
of the projected trends in population and energy consumption growth and
in the absence of little indication of the required social and political
atmosphere, the alternative is not considered realistic at this time.
Eventually, a national as well as world policy to balance energy con-
sumption with energy supplied from renewable resources will have to be
made. This eventuality will probably result in a social as well as an
economic change, but if it is approached in a planned and orderly manner,
the quality of life might indeed improve. Integral to any plan to limit
load growth would be a program of energy education which would make
people aware of the necessity for and the economics appreciated from a
reduction in energy waste and improved efficiency of electrical energy
usage. The Alaska Power Administration recognizes conservation measures
in their load projections, assuming substantial demand savings through
conservation programs and increased efficiency in use of energy.
Coal:
Coal is the most abundant fossil fuel in the nation; however, there
are no known sizable coal deposits in the area surrounding Valdez. A
major obstacle to coal usage is meeting air quality standards when the
coal is burned. Other problems include environmental impacts associated
with strip mining, such as surface disturbance, waste material disposal,
chemically active water discharge, post-mining restoration, and trans-
portation of the coal. The coal alternative could be available on about
the same time frame as other major new power sources such as hydropower
and, possibly, nuclear power. Due to the relatively small energy demand
of the Valdez area, a large coal-fired plant could not be economically
utilized unless a large intertie network was developed.
Natural Gas and Oil:
Alaska power systems now depend on oil and gas for about 60 percent
of total energy production, and by 1980 about 90 percent of the State's
electric energy will come from these fuels. Estimated 1972 fuel use
for Alaska's power systems included 1.4 million barrels of oil and 16
21
billion cubic feet of natural gas. The use would increase to about 26
million barrels of oil and 134 billion cubic feet of natural gas (if
available) annually by the year 2000 in meeting the midrange consumption
level estimates.
Although natural gas, and to a lesser extent oil, has provided low
cost power benefits for many portions of Alaska, the national and inter-
national energy crisis has and will in all probability, result in larger
increased prices for the future. There is the increasing pressure of
the national policy to conserve our nonrenewable resources so that we
may be independent of foreign sources. A national effort to develop
alternatives for power generation such as coal, hydro, solar, wind tides,
and eventually nuclear power could result in substantial reduction in
demand for oil and natural gas. However, the lead times and large
investments required to develop alternatives reinforce the point that
oil and natural gas must supply near future requirements.
As indicated previously, the present electrical system in the Valdez
area is powered by diesel generation. The projected cost of fuel oil
in the Valdez area for January 1978 was $0.385/gallon. This price will
most likely increase in the future, but it is providing the required
energy for the Valdez area now.
Nuclear Power:
The use of nuclear power as a commercial electrical energy source
for the nation is expected to increase by the year 1985. Adverse envi-
ronmental impacts are associated with surface and subsurface mining of
uranium, changes in land use, disposal of waste heat, risk of accidents,
and safe disposal of highly radioactive wastes. In spite of these fac-
tors, more than 50 percent of the electrical power of the nation is
expected to be generated by nuclear power by the year 2000. By that
time, breeder plants, which produce additional fuel while they produce
power, will hopefully be available to take over a larger share of the
production of electricity. Possibly at some time in the next century,
nuclear fission plants and proposed nuclear breeder plants will be
replaced by nuclear fusion reactors and by central generating stations
running on solar power. Nuclear power could be a likely long range
source of power for the Valdez area, but it is considered a very distant
option because of the relatively small power markets, cost and environ-
mental factors and the availability of more favorable alternatives.
The foreseeable future for nuclear power generation in the Valdez area
could become favorable only if there is a breakthrough in cost and
technology of small-sized plants. At this time further study of this
alternative is not deemed justified for this report.
22
Geotherma 1 :
Geothermal resources may eventually provide significant power gen-
eration in Alaska; the southcentral railbelt area has substantial geo-
thermal potential. Some of the possible problems associated with the
generation of electrical power from geothermal resources include siting
of facilities, brine disposal, and corrosion. This resource could also
provide usable side products such as heat, water, and chemicals. This
source of energy is not considered a reasonable short-term alternative
to other more proven types of power generation because of the relatively
primitive level of present technological development and high costs.
Further study of this alternative is not deemed justified for this
report.
Solar:
The radiant heat of the sun is another renewable source of energy
that has considerable potential for generating power in the nation and
the world. Use of solar energy to produce electrical power on a large
scale is not presently feasible for the lack of the technology to gen-
erate and to store large amounts of electricity produced by the sun 1 s
radiation. A major disadvantage wherever such a development is pursued
will be the large land area required for the reflector installed to
provide usable amounts of power and thus the large environmental dis-
turbances inherent in such a change in land use. Another disadvantage~
especially in Alaska, will be that during the winter, when demand for
electrical power is greatest, the sun is either absent from or at best
a brief visitor to local skies. Further study of this alternative is
not deemed justified for this report.
l~ind and Tidal:
Research and development proposals for wind generators should improve
future capabilities of wind-powered electrical generating systems. With
increased diesel fuel costs, wind-generated electrical power is a pos-
sible alternative power source for remote areas with small loads.
Wind as an energy resource, however, is very difficult to adapt to
present energy demands because it is very unpredictable and unsteady.
To effectively utilize wind energy, winds must be of high speed and
long duration to provide firm energy. In order for wind power to be
economically competitive with other energy resources it would require
a firming source of energy, such as pumped storage at a considerable
cost and some technical difficulty.
The Port of Valdez might be developed for tidal energy. The mean
lower low water elevation is 0.00 feet and the mean higher high water
is 12.00 feet, which would provide a total gross head of 12 feet. However,
23
such an installation would require a low dam spanning the width of the
Valdez Narrows, a massive cost item in itself, as well a deep draft
lock system to allow super tankers into the Port of Valdez. The dam
would change the entire flow regime of the Port of Valdez with a sig-
nificant potential for extensive adverse efforts on major ecosystems.
Further study of either of these alternatives is not deemed justified
for this report.
Wood:
There are large forest reserves that could be utilized in southeast
Alaska, but are not available in the study area. These same trees have
higher and better uses in wood, paper, and other industries. In addition,
the esthetic, ecological, and environmental impacts of the large harvests
necessary to allow production of large amounts of energy would be massive.
Further study of this alternative is not deemed justified for the report.
Intertie:
A study by the Alaska Power Administration will determine the feasi-
bility of an intertie system between any one of the two cities of Glenn-
allen and Cordova with Valdez. An intertie would increase the load in
the area and increase the marketability of the energy produced. Side
benefits which could be realized could include enhancement of total
system reliability, added flexibility in scheduling facilities mainten-
ance, and at least the capability to eliminate or minimize unnecessary
duplication of staff facilities. However, because of the mountainous
terrain and accompanying winds, any long distance transmission system
would be subject to severe physical pressures and consequently its reli-
ability may be questionable. Intertie via submarine cable would require
excessively large lines at restrictive cost.
Solid Waste:
There does not appear to be an adequate supply of waste products in
the load center to produce enough energy to meet anticipated load growth.
This alternative is not considered feasible to meet the full energy needs
of the load centers; however, it might serve as a source of supplemental
energy and should be pursued further at the local level.
Hydroelectric Alternatives:
Preliminary analysis indicates that the high cost of long transmission
lines or high dams along with the small storage capacity of some of the
sites has ruled them out as feasible projects. Gold Creek, Sheep Creek,
Wortmann Creek, and Silver Lake have been eliminated. These sites are
shown in Figure 1.
24
GLENNALLEN
MILES
Figure 1
25
Solomon Gulch
Allison Creek
Unnamed Creek
Mineral Creek
Lowe River (Keystone Canyon)
ALTERNATIVES SELECTED FOR FURTHER STUDY
The preliminary screening disclosed alternatives which will be
evaluated to determine the economic justification, technical feasibility,
and no adverse environmental effects of such obvious magnitude as to
preclude plan implementation. The selected alternatives are:
Oil
Solomon Gulch
A 11 i son Creek
Mineral Creek
Unnamed Creek
Lowe River
EVALUATION OF ALTERNATIVES
Selection of the best plan from among the alternatives involves
evaluation of their comparative performance in meeting the study
objectives as measured against a set of evaluation criteria.
These criteria derive from law, regulations, and policies governing
water resource planning and development. The following criteria were
adopted for evaluating and alternatives.
Technical Criteria:
The gro\'lth in electrical power demand \'lill be as projected by the
Alaska Power Administration.
That power generation development, from any source or sources, will
proceed to satisfy the projected needs.
A plan to be considered for initial development must be technically
feasible.
National Economic Development Criteria:
The economic criteria applied in plan formulation were those speci-
fied by the Water Resource Council's 11 Principles and Standards" and
other applicable requirements. Basic economic criteria are:
26
1. Tangible benefits must exceed project economic costs.
2. Each separable unit of work or purpose must provide benefits
at least equal to its cost.
3. The scope of the work is such as to provide the maximum net
benefits.
The benefits and costs are expressed in comparable quantitative
economic terms to the fullest extent possible. Annual costs are based
on a 100-year amortization period, an interest rate of 6-5/8 percent,
and January 1978 price levels. The annual charges include interest;
amortization; and operation, maintenance, and replacement costs.
Power benefits are based on the costs of providing the energy output
of any plan by conventional oil-fired thermal generation.
Environmental Quality Criteria:
The environmental quality criteria are as follows:
1. Conservation of esthetics, natural values, and other desirable
environmental effects or features.
2. The use of a systematic approach to insure integration of the
natural and social sciences and environmental design arts in planning
and utilization.
3. The application of overall system assessment of operational
effects as well as consideration of the local project area.
4. The study and development of recommended alternative courses of
action to any proposal which involved conflicts concerning uses of avail-
able resources.
5. Evaluation of the environmental impacts of any proposed action,
including effects which cannot be avoided, alternatives to proposed
actions, the relationship of local short-term uses and of long-term
productivity, and a determination of any irreversible and irretrievable
resource commitment.
6. Avoidance of detrimental environmental effects, but where these
are unavoidable, the inclusion of practicable mitigating features.
Social Well-Being and Regional Development Considerations:
In addition to the basic planning criteria, consideration was given
to:
27
1. The possibility of enhancing or creating recreational values
for the public.
2. The effects, both locally and regionally, on such items as
income, employment, population, and business.
3. The effects on educational and cultural opportunities.
4. The conservation of nonrenewable resources.
The Alternatives:
All alternatives were screened assuming secondary energy as saleable
and setting installed (dependable) capacity at 55 percent plant factor
using primary energy.
Mineral Creek:
Three earthfilled dams would be required in this scheme to create a
reservoir in the Mineral Creek basin. The crest of the dams would be at
200 feet and the spillway would be incorporated into the westerly dam.
The active layer would fluctuate 50 feet and have a storage of approxi-
mately 16,000 acre-feet. The transmission line would be less than 1
mile to the load center and the access road should not be any longer.
The benefits are computed using the Federal Energy Regulatory Commission's
(FERC) power values as shown in Appendix I, Section C. The average
annual energy, installed capacity and benefits for REA financing and
no fuel escalation at alternative elevations are shown below:
Average Average
Prime Annual Installed Annual
Elevation Ener}y Energy Capacity Benefits
(Feet) (MWH (MWH) (KW) ($1,000)
225 6,412 10,144 1,331 536
200 3,811 6,422 791 334
185 2,663 4,689 553 241
175 1,886 3,476 392 177
The average annual cost of a dam at the 200 foot elevation would be
$1,744,480. Since none of the alternatives even approximates the costs
of the optimum scheme (elevation 200 feet) this alternative does not
appear to be economically feasible.
Unnamed Creek:
This scheme would consist of one earthfilled dam with a crest eleva-
tion of 975 feet and a concrete spillway incorporated into the dam. The
28
penstock would consist of two 5 foot diameter pipes about 3,170 feet
long. The transmission line would follow the existing road and be
approximately 15 miles long. The access road would be about 4 miles
long and require a bridge across the lowe River. The active storage
available would be about 33,000 acre-feet. The benefits are computed
using FERC power values. The average annual energy~ installed capacity,
and benefits for REA financing and no fuel escalation at alternative
elevations are shown below:
Elevation
(Feet)
1,100
1,000
975
950
Prime
Energy
{MV.JH)
50,000
30,386
23,409
17,480
Average
Annual
Energy
(MWH)
58,354
40,436
32,945
25,937
Installed
Capacity
{KW}
10,378
6,307
4,859
3,628
Average
Annual
Benefits
($1,000)
3,382
2,247
1,800
1,396
The average annual cost of the scheme at the 975 elevation would be
$5,091,000. In this light it does not appear that any economically
feasible project exists at this site.
Lowe River:
This scheme would require a small dam about 80 feet high with a crest
elevation of 480 feet. The transmission line would be approximately 19
miles long and follow the existing highway. A 2.5 mile portion of the
Richardson Highway would have to be relocated. The amount of active
storage available would be approximately 9,000 acre-feet. Higher dams
than the presented scheme were not considered because of the large
environmental impacts and conflicts with the Trans-Alaska Pipeline and
the Richardson Highway. The benefits are computed using FERC power
values. The average annual energy, installed capacity, and benefits
for REA financing and no fuel escalation at alternative elevations are
shown below:
Average Average
Prime Annual Installed Annual
Elevation Energy Energy Capacity Benefits
(Feet} (MWH} {MWH) (KW) ($1,000)
480 3,400 5,673 706 296
470 2,660 4,517 552 234
460 2 '1 01 3,629 436 186
450 904 1 ,841 188 92
29
The average annual cost of this scheme would be $1,157,000. This
cost makes it apparent that there is not an economically feasible project
at this site along with the environmental problems that would be encoun-
tered.
Allison Creek:
Dam: A small rockfilled dam to the 1,400 foot elevation and trench-
ing down deep enough into the glacial nmraine for the penstock intake
would be required to develop the necessary storage. Allison Lake is a
deep lake with a gradually tapering glacial moraine at its outlet. The
scheme with a small dam to the 1.400 foot elevation and trenching down
to the 1,330 foot elevation for a penstock with intake would develop
approximately 20,158 acre-feet of storage. A 10.5 mile long transmission
line will be required between the powerhouse and Valdez. There would
not be a road to the damsite which means all transportation to the dam-
site would be by helicopter. The benefits are computed using FERC power
values. The average annual energy, installed capacity, and benefits for
REA financing and no fuel escalation at alternative elevations are shown
below for a dam schemes with a drawdown to 1,330 foot elevation.
Average Average
Prime Annual Installed Annual
Elevation Energy Energy Capacity Benefits
(Feet) (t1\~H) ( MvJH) (KW) ($1,000)
1,400 34,244 36,819 7,108 2,195
1 ,390 32.461 35,951 6,737 2 '121
1,380 25,983 32,335 5,393 1 ,835
1 ,367 18,978 26,354 3,939 1 ,446
The average annual cost of the 1,400 foot elevation scheme is approxi-
mately $2,433,750. This estimate was computed using a small dam with
minimal foundation preparation. After the field reconnaissance it was
realized that this would not be possible. As indicated in the Appendix
under Section E, Regional Geology, it was felt that Allison Creek would
not be a good site for a dam and, therefore, this scheme will not be
considered.
Lake Tap: ~ Another alternative type of development for Allison
Creek would be a lake tap. This scheme would involve a lake tap and a
tunnel with a penstock in it. The storage reservoir would be operated
from the natural lake outlet elevation of 1,367 feet and fluctuate down
to the 1,267 foot elevation with a total storage capacity of 20,678
~ After screening both Solomon Gulch and Allison Creek it was found
that a 50 percent plant factor was more representative and was
utilized in the computations.
30
acre-feet. The benefits are computed using FERC power values. The
average annual energy, installed capacity, and average annual benefits
for REA financing and no fuel escalation in this scheme are shown below:
Average Average
Prime Annual Installed Annual
Elevation EnerJy Energy Capacity Benefits
(Feet) (MWH (MWH) (KW} ($1,000)
1 t 367 33,116 35,749 7,560 2,203
The average annual cost of this scheme is about $2,450,000 which
indicates that it could possibly be an economically feasible project
if fuel escalation was taken tnto account. ·
Solomon Gulch: ~
The scheme which was looked at for this location was a 115 foot high
concrete gravity dam with three small adjacent rockfilled dams. The
spillway would be included in the concrete gravity dam with a crest of
665 feet. The power pool would operate between the 685 and 631 foot
elevation with a storage of 25,650 acre-feet.· The transmission line
would be about 9 miles long. The benefits are computed using FERC
power values. The average annual energy, installed capacity, and average
annual benefits for REA financing in this scheme are shown below:
Elevation
(Feet)
685
Prime
Energy
(MWH)
28,502
Average
Annual
Energy
(MWH)
40,780
Insta 11 ed
Capacity
(KW)
6,200
Average
Annual
Benefits
($1,000)
2,250
The average annual cost of this scheme at the 685 foot elevation is
approximately $2,712,000. This indicates that there could possibly be
an economically feasible project if fuel escalation was taken into
account.
Oi 1 :
Oil is the most likely alternative for power production in the Valdez
area since the majority of their power is produced by that means now.
It is believed that a Delaval unit would be installed. This diesel
engine-driven unit is rated at 2,625 KW wi.th a heat rate of 9,370 BTU/KWH,
investment cost of $665 per KW, and a service life of 35 years. This
unit was used in the derivation of the power values for the benefits
which would be accrued by hydropower in lieu of diesel.
31
THE SELECTED PLANS
The two sites that were selected for further evaluation in the
Valdez area were Solomon Gulch and Allison Creek and are shown in
Plates 1, 2, and 3 for Solomon and 4 and 5 for Alltson. Area photo-
graphs are shown on Figures 2 and 3 for the sites.
SOLOMON GULCH
This scheme would consist of a concrete gravity dam with a gated
spillway and three minor rockfilled dams to the east of the concrete
gravity dam. There would be a 12 inch pipe to release water into the
stream channel for fish. There also would be a 4 foot square intake
chamber for power production. The reservoir would be operated between
elevation 685 and 631 to generate the required power. The powerhouse
would be located adjacent to the tide waters of the Port of Valdez and
the road to the pipeline terminal. The transmission line would be
approximately 9.0 miles long to CVEA's bus.
ALLISON CREEK -LAKE TAP
This scheme would involve a lake tap at the 1,250 foot elevation,
a surge tank, a 6 inch pipe diversion, and a powerhouse. The lake tap
would draw the lake down from its present elevation of 1,367 to 1,267
to generate power. The tunnel would be a 10 foot wide by 10 foot high
horseshoe. A 3-foot diameter penstock would be run inside the tunnel
and then down to the powerhouse which is located adjacent to the tide
water of the Port of Valdez. There would be an underground surge tank
connected into the penstock and it would rise approximately 150 feet.
There would be a 6 inch diameter steel pipe which would provide enough
water to the main channel for Alyeska's water supply and for fish
purposes. The transmission line would be about 10.5 miles long.
32
Figure 2 Solomon Gulch
Figure 3 Allison Creek
33
ECONOMICS OF THE SELECTED PLANS
r/2 '!) 712 ')'jq
) ")
COST
As indicat~d by Appendix I, Sec~ion B, the vera e annual cQs_t ~
Solomon Gulch and Allison Creek proJects are , , and $:_96lg, •
This includes ·.interest during construction an operation and maintenance
cost. The total cost was amol"ti·zed ·at 6-5/8 percent interest over a
projected ·economic ltfe of 100 years to yield the average .annual cost.
BENEFITS
The benefits were calculated using .only power benefits. The evalua-
tion was made using a FERC value plus three fuel escalation factors.
It was felt that full value should be given to the aver.age .annual energy
as indicated in Appendix I, Section C. The tabulation below shows the
benefits/cost (B/C) ratio using the information from Page C-19.
BENEFIT/COST RATIO
REA Financing (6.4%)
Capacity
& Prime
Energy
Solomon Gulch
FERC 0.65
FERC + 1% ~ 0.72
FERC + 2% 0.80
FERC + 3% 0.91
Allison Creek
FERC
FERC + 1%
FERC + 2%
FERC + 3%
0.86
0.94
1.05
1.18
Capacity
Prime & 1/2
Secondary
Energy
0.74
0.82
0.92
1.04
0.88
0.97
1.08
1. 21
Capacity
& Average
Annual
Energy
0.83
0.92
1.04
1.18
0.90
0.99
1.10
1.24
Federal Financing (6.625%)
Capacity
& Prime
Energy
0.64 o. 71
0.79
0.89
0.84
0.92
1.02
1.16
Capacity
Prime & 1/2
Secondary
Energy
0.73
0.81
0. 91
1.03
0.86
0.95
1.06
1.19
Capacity
& Average
Annual
Energy
0.81
0.90
1.02
1.16
0.88
0.97
1.09
1.23
3/ 1 percent, 2 pel"Cent,.and 3 percent refers to the fuel escalation as
shown in Appendix C.
34'
JUSTIFICATIONS
As indicated by the B/C ratios, neither of the projects would be
considered economically justified except with the fuel escalated power
values. It should be noted that FERC formerly FPC produced their Draft
Environmental Impact Statement on Solomon Gulch with a 3 percent escala-
tion of fuel cost (see Appendix 1, Section C). Therefore, it 1s felt
that the benefits associated with the 3 percent fuel escalation are
valid in the evaluation of the two projects.
35
SUMMARY
This report has considered the need for development of power in the
Valdez area. A broad range of alternative means of accomplishing the
primary study objective were examined for technical, economic, and
environmental feasibility. Included were both conventional power pro-
ducing systems based on coal, oil, gas, nuclear energy, and hydroelectric
energy, and less conventional systems based on wind, tides, solar energy,
solid wastes, wood, and geothermal energy.
The oil and hydroelectric energy were both found to be feasible.
An indepth evaluation of these alternatives will be made giving equal
consideration to economic and environmental aspects of their performance.
Each alternative was found to have a marginal economic performance
and each was found to have a range of unavoidable adverse effects on
the environment, mainly on fish and wildlife, and esthetic values.
If CVEA develops Solomon Gulch it will most likely expand the market
by an intertie with Glennallen. The additional demand, as indicated in
Appendix C, would absorb all of the average annual energy from both
Solomon Gulch and Allison Creek and probably require some supplemental
diesel generation.
The two sites, Solomon Gulch and Allison Creek, were found to be
the most feasible water and related land resources development. These
two plans are considered the most favorable with the maximum of net
benefits, the least unavoidable adverse environmental impacts, and the
greatest response to the multiple study objectives. Therefore, these
two sites will be addressed in greater depth in the feasibility report.
36
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VALDEZ INfERI),I REPORT
SOUTHCENTRAL R~LBCLT
ALLISON CREEK
APRil 1978
PLATE N0.4 8-19
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SECTION C
POWER STUDIES AND ECONOMICS
SECTION C
POWER STUDIES AND ECONOMICS
Item
INTRODUCTION
PROJECTED ENERGY NEEDS
POSSIBLE SOLUTIONS
TABLE OF CONTENTS
Alternative Sources of Power
No growth
Coal
Natural Gas and Oil
Nuclear
Geothermal
Solar
Wind and Tide
Wood
Intertie
Solid Waste
Hydroelectric
HYDROPOWER ANALYSIS
Method of Analysis
Scope
Glossary
Methodology
POWER PRODUCTION VARIABLES
Free Surface Evaporation
Head Loss and Tailwater Elevation
Plant Factor
Monthly Energy Distribution
Power Values and Alternative Cost
Power Values
Fuel Costs
HYDROELECTRIC ALTERNATIVES IN THE VALDEZ AREA
Allison Creek
Solomon Gulch
Benefits
Conclusions
C-1
C-2
C-3
C-3
C-3
C-4
C-4
C-5
C-5
C-6
C-6
C-6
C-7
C-7
C-7
C-8
C-8
C-8
C-8
C-11
C-12
C-12
C-12
C-12
C-12
C-13
C-13
C-14
C-18
C-18
C-18
C-18
C-19
INTRODUCTION lJ
The only producer of electrical power for the public in the Valdez
area is Copper Valley Electric Association (CVEA). CVEA is a distribu-
tion type Rural Electric Association (REA) which generates all of its
power requirement for Valdez from diesel units and a gas turbine. The
Valdez system came into existence following the 27 March 1964 earthquake,
which demolished the town. Studies followed the quake determined that
the townsite be abandoned. A new Valdez was built at a location approxi-
mately 5 miles west of the original townsite.
The Valdez Light, Power, and Telephone Company served the Valdez
area prior to the earthquake. The generating and distribution facilities
of this company were purchased by the Urban Renewal Agency which, in
turn, sold the facilities to Copper Valley Electric Association. The
old facilities were obsolete, in poor condition, and were used only until
new facilities were operable.
The Copper Valley Electric Association obtained a Certificate of
Convenience from the State of Alaska and a franchise from the new city
of Valdez to own and operate the electric system serving the new Valdez.
The Certificate of Convenience covers the general area and is not con-
fined to the limits of the new townsite.
The Valdez system presently serves approximately 1,400 consumer
units over about 25 miles of distribution lines. The system serves
the new city of Valdez, the old Valdez area, consumers from old Valdez
to the airport area, and 10 miles east of old Valdez along the Richardson
Highway.
The existing powerplant contains the following diesel and gas turbine
units:
3 -600 KW, 720 rpm, Fairbanks Morse (1967)
1 -1,928 KW, 400 rpm, Enterprise (1972)
1 -965 KW, 360 rpm, Enterprise (1974)
1 -2,620 KW, 450 rmp, Enterprise (1975)
1 -2,800 KW, gas turbine (1976)
Total Installed Capacity
1,800 KW
1 ,928 KW
965 KW
2,620 KW
2,800 KW
10,113 KW
!J Copper Valley Electric Association, Inc. 15 Year Power Cost Study,
Robert W. Retherford Associates, November 1976
C-1
PROJECTED ENERGY NEEDS
The most recent estimate of utility loads is a study prepared for
CVEA. 1/ The impact of the pipeline in the area has continued to
increase the demand for additional energy. The following is the pro-
jection from the study mentioned above and also illustrated in Graph
C-1.
1980 1985 1990
Demand KW 5,800 8~600 12~800
Energy M~JH 27,900 41,400 61,400
The energy produced for 1973-1976 is shm11n below:
Years Energy {MWH)
1973 6,470
1974 9,460
1975 18,250
1976 26,000
This indicates a rapid rate of growth even after the majority of
the pipeline construction was finished. It seems that the projected
figure for 1980 of 27,900 MWH of energy may be attained earlier than
projected. The subsequent figures would also probably be reached earlier
which only reinforces the need for additional energy in the Valdez area.
If Glennallen was tied into a system with Valdez it would increase
the demand for the area. CVEA's study also gives a projection for the
total demand of Valdez and Glennallen as shown in Graph C-2.
Y Copper Valley Electric Association, Inc. 15 Year Power Cost Study,
Robert W. Retherford Associates, November 1976
C-2
POSSIBLE SOLUTIONS
The following alternative methods of satisfying the primary study
objective, the provision of electric power for the Valdez area, were
considered as possible solutions:
Alternative Sources of Power
No Growth
Coal
Natural Gas and Oil
Nuclear
Geothermal
Solar
Hydroelectric Alternatives
Solomon Gulch
Allison Creek
Wind and Tide
Wood
Intertie
Solid Waste
Hydroelectric
These alternatives were screened on the basis of preliminary esti-
mates of response to the basic water resource planning objectives of
NED (economic viability) and EQ (contributions to environmental quality).
Within the NED considerations, in addition to the purely economic factors,
such items as technical feasibility (can it be done with existing tech-
nology?) and scale (does it do too little or too much?) were considered
important. Within the EQ considerations, in addition to positive con-
tributions to environmental factors, a lack of adverse effects was con-
sidered significant. The intent and effect of this brief screening was
to rule out impracticable and marginal alternatives leaving a small
number of the better possible solutions to be studied and evaluated in
detail. The following discussions summarize the preliminary evaluation.
ALTERNATIVE SOURCES OF POWER
No Growth:
Restricting the growth in power demand and altering energy pr1c1ng
policies are political decisions that cannot be addressed in this report
with any authority. However, any adopted policy significantly reducing
industrial consumption of energy would have to consider the living stan-
dard which to a large extent depends on energy consumption. It would
also be necessary for a policy to restrict population growth and to
apply to all forms of energy to be effective. This alternative would
achieve the maximum possible conservation of nonrenewable resources and
have minimal adverse environmental impacts. However, in the presence
of the projected trends in population and energy consumption growth and
C-3
in the absence of little indication of the required social and political
atmosphere~ the alternative is not considered realistic at this time.
Eventually, a national as well as world policy to balance energy con-
sumption with energy supplied from renewable resources will have to be
made. This eventuality will probably result in a social as well as an
economic change, but if it is approached in a planned and orderly manner,
the quality of life might indeed improve. Integral to any plan to limit
load growth would be a program of energy education which would make
people aware of the necessity for and the economics appreciated from a
reduction in energy waste and improved efficiency of electrical energy
usage. The Alaska Power Administration recognizes conservation measures
in their load projections, assuming substantial demand savings through
conservation programs and increased efficiency in use of energy.
Coal:
Coal is the most abundant fossil fuel in the nation; however, there
are no known sizable coal deposits in the area surrounding Valdez. A
major obstacle to coal usage is meeting air quality standards when the
coal is burned. Other problems include environmental impacts associated
with strip mining, such as surface disturbance, waste material disposal,
chemically active water discharge, post-mining restoration, and trans-
portation of the coal. The coal alternative could be available on about
the same time frame as other major new power sources such as hydropower
and, possibly, nuclear power. Due to the relatively small energy demand
of the Valdez area, a large coal-fired plant could not be economically
utilized unless a large intertie network were developed.
Natural Gas and Oil:
Alaska power systems now depend on oil and gas for about 60 percent
of total energy production, and by 1980 about 90 percent of the State 1 s
electric energy will come from these fuels. Estimated 1972 fuel use for
Alaska 1 S power systems included 1.4 million barrels of oil and 16 billion
cubic feet of natural gas. The use would increase to about 26 million
barrels of oil and 134 billion cubic feet of natural gas (if available)
annually by the year 2000 in meeting the midrange consumption level
estimates.
Although natural gas, and to a lesser extent oil, has provided low
cost power benefits for many portions of Alaska, the national and inter-
national energy crisis has and will in all probability, result in larger
increased prices for the future. There is the increasing pressure of
the national policy to conserve our nonrenewable resources so that we
may be independent of foreign sources. A national effort to develop
alternatives for power generation such as coal, hydro, solar, wind tides,
and eventually nuclear power could result in substantial reduction in
C-4
demand for oil and natural gas. However, the lead times and large
investments required to develop alternatives reinforce the point that
oil and natural gas must supply near future requirements.
As indicated previously, the present electrical system in the Valdez
area is powered by diesel generation. The projected cost of fuel oil
in the Valdez area for January 1978 was $0.0385/gallon. This price
will most 1 ikely increase in the future, but it is providing the required
energy for the Valdez area now.
Nuclear Power:
The use of nuclear power as a commercial electrical energy source
for the nation is expected to increase by the year 1985. Adverse envi-
ronmental impacts are associated with surface and subsurface mining of
uranium, changes in land use, disposal of waste heat, risk of accidents,
and safe disposal of highly radioactive wastes. In spite of these fac-
tors, more than 50 percent of the electrical power of the nation is
expected to be generated by nuclear power by the year 2000. By that
time, breeder plants, which produce additional fuel while they produce
power, will hopefully be available to take over a larger share of the
production of electricity. Possibly at some time in the next century,
nuclear fission plants and proposed nuclear breeder plants will be
replaced by nuclear fusion reactors and by central generating stations
running on solar power. Nuclear power could be a likely long range
source of power for the Valdez area, but it is considered a very distant
option because of the relatively small power markets, cost and environ-
mental factors and the availability of more favorable alternatives. The
foreseeable future for nuclear power generation in the Valdez area could
become favorable only if there is a breakthrough in cost and technology
of small-sized plants. At this time further study of this alternative
is not deemed justified for this report.
Geothermal:
Geothermal resources may eventually provide significant power gener-
ation in Alaska; the southcentral railbelt area has substantial geothermal
potential. Some of the possible problems associated with the generation
of electrical power from geothermal resources include siting of facili-
ties, brine disposal, and corrosion. This resource could also provide
usable side products such as heat, water, and chemicals. This source
of energy is not considered a reasonable short-term alternative to other
more proven types of power generation because of the relatively primi-
tive level of present technological development and high costs. Further
study of this alternative is not deemed justified for this report.
C-5
Solar:
The radiant heat of the sun is another renewable source of energy
that has considerable potential for generating power in the nation and
the world. Use of solar energy to produce electrical power on a large
scale is not presently feasible for the lack of the technology to gen-
erate and to store large amounts of electricity produced by the sun 1 s
radiation. A major disadvantage wherever such a development is pursued
will be the large land area required for reflector installed to provide
usable amounts of power and thus the large environmental disturbances
inherent in such a change in land use. Another disadvantage, especially
in Alaska, will be that during the winter, when demand for electrical
power is greatest, the sun is either absent from or at best a brief
visitor to local skies. Further study of this alternative is not deemed
justified for this report.
Wind and Tidal:
Research and development proposals for wind generators should improve
future capabilities of wind-powered electrical generating systems. With
increased diesel fuel costs, wind-generated electrical power is a pos-
sible alternative power source for remote areas with small loads.
Wind as an energy resource, however, is very difficult to adapt to
present energy demands because it is very unpredictable and unsteady.
To effectively utilize wind energy, winds must be of high speed and long
duration to provide firm energy. In order for wind power to be economi-
cally competitive with other energy resources it would require a firming
source.
The Port of Valdez might be developed for tidal energy. The mean
lower low water elevation is 0.00 feet and the mean higher high water
is 12.00 feet, which would provide a total gross head of 12 feet. How-
ever, such an installation would require a low dam spanning the width
of the Valdez Narrows, a massive cost item in itself, as well as a deep
draft lock system to allow super tankers into the Port of Valdez. The
dam would change the entire flow regime of Port of Valdez with a signifi-
cant potential for extensive adverse effects on major ecosystems. Further
study of either of these alternatives is not deemed justified for this
report.
Wood:
There are large forest reserves that could be utilized in southeast
Alaska, but are not available in the study area. These same trees have
higher and better uses in wood, paper, and other industries. In addition,
the esthetic, ecological, and environmental impacts of the large harvests
necessary to allow production of large amounts of energy would be massive.
Further study of this alternative is not deemed justified for the report.
C-6
Intertie:
A study by the Alaska Power Administration will determine the feasi-
bility of an intertie system between any one of the two cities of Glenn-
allen and Cordova with Valdez. An intertie would increase the load in
the area and increase the marketability of the energy produced. Side
benefits which could be realized could include enhancement of total
system reliability, added flexibility in scheduling facilities mainte-
nance, and at 1 east the capability to eliminate or minimize unnecessary
duplication of staff facilities. However, because of the mountainous
terrain and accompanying windst any long distance transmission·system
would be subject to severe physical pressures and consequently its
reliability may be questionable. Intertie via submarine cable would
require excessively large lines at restrictive cost.
Solid Waste:
There does not appear to be an adequate supply of waste products in
the load center to produce enough energy to meet anticipated load growth.
This alternative is not considered feasible to meet the full energy needs
of the load centers; however, it might serve as a source of supplemental
energy and should be pursued further at the local level.
Hydroelectric Alternatives:
Preliminary analysis indicates that the high cost of long transmission
lines, high dams and small storage capacity of some sites has ruled them
out as feasible projects. The sites with these problem areas that have
been eliminated are: Gold Creek, Sheep Creek, Wortmann Creek, Silver
Lake, Mineral Creek, Lowe River, and Unnamed Creek. There are two others
which do merit more analysis and those are: Allison Creek and Solomon
Gulch.
C-7
HYDROPOWER ANALYSIS
METHOD OF ANALYSIS
Scope:
As discussed in the preceding section, Possible Solutions, several
hydro projects in the Valdez area were considered worthy of further
study. Simulation operation studies were made to determine the power
potential of these projects.
Glossary:
The following terms are defined:
Energy:
Average Energx: The average amount of energy produced each
year by a hydro proJect over a specific period of operation or study.
Firm Energy: Annual electric energy which is required to be
available at all times based on the most critical year and period of
recorded streamflows.
Prime Ener : The maximum energy expressed in average kilowatt-
hours or megawatt-hours) that can be produced at a hydro project during
the most critical streamflow period. Prime energy would serve to meet
firm energy loads.
Secondary Energy: Electric energy having limited availability.
In a good water year, a hydro plant can generate energy in excess of its
prime energy capability. This excess energy is classified as secondary
energy because it is not available every year, and varies in magnitude
in those years when it is available.
Usable Energy: The amount of energy generated by the hydro system
for which there is an apparent market.
Capacity:
Installed Ca~acity: The rating of the generators at design load
and best gate avai able for the production of saleable power.
Dependable Capacity: The assured peak load-carrying ability of a
plant or system under adverse water conditions for the time interval and
period specified when related to the characteristics of the load to be
supplied, expressed in kilowatts (or megawatts). In these studies
dependable and installed capacity are identical.
C-8
Reserve Capacity: Capacity in excess of that required to carry
peak load and which is available to meet unanticipated demands for
power or to generate power in the event of scheduled or unscheduled
outages.
Power Values:
Capacity Value: That part of the at-site or at-market value of
electric power which is assigned to dependable capacity. This is based
on the amortized investment costs and fixed operating costs of the most
economical alternative power source.
Energy Value: That part of the at-site or at-market value of
electric power which is assigned to energy. This is based largely on
fuel and variable operating costs for the most economical alternative
power source.
At-Market Value: The value of hydroelectric power at the market
as measured by the cost of producing th~ equival~nt power by the most
economical means and delivering this power to the market.
At-Site Value: The value of power at the site of the generating
station as measured by the at-market value minus the cost of transmission
facilities and losses from generating station to market.
Head:
Critical Head: The head at which the dependable capacity can be
produced at full-gate opening.
Design Head: The head at which the turbine will operate to give
the best overall efficiency under various operating conditions.
Rated Head: The head at which a turbine will deliver maximum
generator capac1ty at full gate.
Reservoir Criteria:
Drawdown: The distance that the water surface of a reservoir is
lowered from a given elevation as the result of the withdrawal of water.
Adverse Water Conditions: The most adverse sequence of flows
from the standpoint of hydro system energy production. This sequence
is a function of the amount of reservoir storage available and the power
system load requirements and is usually determined by testing the full
record of historical streamflow conditions.
C-9
Operating or Power Year: For purposes of this report, a 12-month
period beginning 1 October.
Critical Period: The interval of time when hydro energy production
is limited by adverse water conditions. The period begins with reservoir(s)
full and ends with reservoir(s) empty just prior to a sequence of flows
which will refill the reservoir(s). Average energy produced during the
critical period is called prime energy.
Critical Period Storage: The amount of water in storage which
could be drafted to augment the low natural flows associated with the
critical period.
Storage Refill Period: The period of time required to refill
reservoir following the critical period draft.
Dead Stora~e: The amount of storage within the reservoir which
lies below the m1nimum elevation to which the reservoir surface could
be lowered. The minimum reservoir surface elevation is a function of
the head range within which the turbines are designed to operate at
greatest efficiency.
Usable Storage: The amount of reservoir storage which lies within
the elevations above the dead storage pool and below the full reservoir
pool. This storage is the water which is available to augment natural
streamflow during the critical period.
Power Terms:
P.O. Power-on-line date.
Load Shape: Daily and annual load curves reduced to a percentage
factor of a specified load. For example, it is common to indicate the
monthly loads for both energy and capacity in percentage of annual
energy and annual peak loads.
Area Load Factor: The ratio of the average load over a designated
period to the peak load occurring in that period, for integrated load
center.
Plant Factor: The ratio of average plant output to installed
capacity for a given period.
Load Center: A point at which a large share of the load of a
given area is assumed to be concentrated.
Base Load: The minimum amount of load required 24 hours a day.
C-10
Peak load: The maximum instantaneous load within a specified
time.
Methodology:
Power analysis of the study area was based on the hydrologic data
available from the various stream gaging stations within the study area.
The study period covered was the 28 years of record that were available
at Power Creek near Cordova. The two stations of Solomon Gulch and
Lowe River were extended by correlation with Power Creek. The other
potential hydropower sites, Mineral Creek, Unnamed Creek, and Allison
Creek had their flows derived from the Solomon Gulch streamflows and
adjusted according to a ratio of their respective areas. The analysis
of the power output for the differnt schemes in the study area was
accomplished by utilizing a computer program developed by the Alaska
District for reservoir system analysis. The projected energy load
growth, the monthly energy demand shape, and annual load factor were
derived from the existing data for this report.
C-11
POWER PRODUCTION VARIABLES
Many variables were considered prior to commencement of the power
study. A brief discussion of the assumptions and variables used is
presented in the following text.
FREE SURFACE EVAPORATION
The normal high relative humidity, high percentage of overcast days
and relatively cool climate probably precludes any appreciable percent-
age of water loss from evapotranspiration. Estimates of flow were
based on records of existing or historical gaging stations near the
project areas. These records would reflect any past evaporation and
for these reasons, no corrections were made in the run-off analyses
for evaporation.
HEAD LOSS AND TAILWATER ELEVATION
Power head losses were confined to fluctuations in the tailwater
elevations and to hydraulic losses through the tailrace, turbines, pen-
stocks, and power tunnels. The tailwater elevation (as shown below) was
added to the head (friction) losses to obtain the net head available for
power production.
Project
Allison
Solomon Gulch
PLANT FACTOR
Tailwater Elevation MSL (ft)
10
15
For the purpose of this study, a 50 percent annual plant factor was
used in the hydropower studies. The assumption of a 50 percent annual
plant factor will insure capability to serve a proportional share of
both peaking and energy requirements throughout the year, and adequate
flexibility to meet changing conditions in any given year.
MONTHLY ENERGY DISTRIBUTION
The monthly distributions are an average of the month demand for
energy in the years 65, 66, 67, 68, 69, 74, and 75. The years not
included had insufficient data and could not be incorporated into the
averages. The monthly load distributions used in this study are pro-
vided below.
C-12
Month
January
February
March
April
May
June
July
August
September
October
November
December
Total
Monthly Energy
Percent of Annual Total
8.5
8.2
7.2
7.4
7.3
7.4
7.3
7.9
8.6
9.0
10.1
11.1
100.0
POWER VALUES AND ALTERNATIVE COST
The basic power values and alternative costs for the system were
developed by the San Francisco Regional Office of the Federal Energy
Regulatory Commission (FERC). Power values were divided into two com-
ponents, the dependable capacity value and the energy value. Taxes
and insurance costs, as applicable, are included in the power value.
The method of analysis used by the FERC in developing power values is
presented in Hydroelectric Power Evaluation, by the Federal Power Com-
mission, dated March 1968.
POWER VALUES
The at-market values of dependable hydroelectric power delivered
in Valdez are based on estimated costs of power from alternative diesel-
engine driven generating plants. The alternative plant would consist of
2,625 KW units with a heat rate of 9,370 BTU/KWH, capital cost of $655
per kilowatt, service life of 35 years, and fuel oil cost of 38.5 cents/
gallon. Values are based on 1 January 1978 price levels and are given
for Federal financing at 6-5/8 percent interest and for REA financing
at 6.4 percent interest rate.
Federal Financing @ 6.625%
REA Financing@ 6.4%
C-13
At-Market Value of
Dependable Hydroelectric Power
(price level -1/1/78)
$/KW-yr
102.69
109.02
mi 11 s/KWH
38.57
35.57
The values include a 5 percent hydro-diesel capacity adjustment
added to the at-market cost. For this preliminary study energy value
adjustments were not made because of the uncertainty of some future
resources and judgment dictated that this adjustment would be small.
FUEL COSTS
The following is an analysis of the cost escalation of fuel for the
diesel alternative. Since the economy in the Valdez area has been
effected so much by the installation of the Trans-Alaska Pipeline, it
was felt that the Anchorage area trend in fuel prices would be more
representative in the long run than the values in Valdez.
Table C-1 shows a 10-year record of Alaskan oil prices taken from
three oil dealers in the Anchorage area. Also shown are the annual rates
of growth of the fuels over varying lengths of time. The 1976 average
fuel cost for the three companies is 0.39/gallon. For the 10-year period,
the average annual increase in the cost of these fuels was 8.7 percent.
Since 1971, however, when fuel prices started their dramatic climb, the
average fuel rate increases have been on the order of 16 percent per
annum. The wholesale fuel rates represent the price of fuel delivered
at dock to the distributor.
TABLE C-1
ANCHORAGE OIL PRICES
Years Wholesale Bulk Retail
Period Rate Period Rate Period Rate
Year Compounded $/gal Increase $/ga 1 Increase ${gal Increase
1966 10 . 127 9.7 • 185 8.3 .205 8.2
1967 9 . 127 10.9 . 185 9.2 .210 8.9
1968 8 . 127 12.3 . 185 10.5 . 215 9.7
1969 7 . 127 14.2 . 185 12.0 .220 10.8
1970 6 • 134 15.7 . 190 13.7 .228 12.0
1971 5 . 141 17.9 . 192 16.4 .235 13.9
1972 4 . 132 24.9 . 194 20.6 .300 1 o. 7
1973 3 . 132 34.5 .200 27.0 . 401 4.0 1974 2 . 187 31.0 .320 13.2 . 410 4.9
1975 1 . 307 4.6 . 360 13.9 • 416 8.4 1976 . 321 • 410 .451
With the emphasis that is being placed on solving our energy problems
at the national level, it would not be prudent to assume that our advanc-
i~g technology will create an answer. Unfortunately, there is no infal-
11ble way to look into the future to determine if and when a specific
C-14
energy source may become available. Since there is no assurance that
an answer is forthcoming, it is necessary to analyze existing resources
in the most logical manner to determine which options should be pursued.
In this respect, there is reason to question the validity of the method
by which we determine economic feasibility for hydropower development.
While we are not legally bound to the analytical methods used by the
Federal Energy Regulatory Commission, we seek their power analysis in
order to maintain an unbiased posture. This does not assure, however,
a realistic judgement of hydro feasibility. The Federal method of
expressing the value of hydroelectric power is based on the lowest cost
of equivalent energy and capacity as produced by the most economical
alternative to the hydro project, which in the case of Valdez area,
are diesel units. As mentioned earlier, these benefits are determined
by FERC in the form of power values. In deriving power values for use
in benefit analysis, FERC uses present day costs for construction of
the alternative, which is equivalent to the Federal procedure for hydro
development. However, FERC also uses present day costs for the fuel
requirement of the alternative which contribute to the hydro energy
benefit. This is not equitable in a period of substantial escalation
of fuel costs. Whereas, a hydro development will continue to receive
its annual energy from falling water without increased investment, the
continuing depletion of fossil fuels and escalating extraction costs
will surely result in higher future fuel costs, and thereby increase
the cost of fossil fuel generated energy. It would only appear reason-
able that this should be recognized in the evaluation of hydropower
with resulting increased energy benefits. Furthermore, as a renewable
resource that does not deplete oil supplies, hydro does not agitate the
competition for petroleum. Thus there appears to be sufficient justi-
fication to evaluate the feasibility of hydropower development in the
Valdez area by attempting to account for the present worth of future
fuel costs.
The energy value provided by FERC consist of the cost of fuel an,
a variable operation and maintenance cost. As mentioned earlier, the
fuel component represents $0.385/gal which equates to 2,789 mills per
million BTU. The formula used by FERC to compute the energy value of
a fossil fuel-fired plant with a 50 percent plant factor is as follows.
O&M + 90 percent x heat rate x fuel cost = energy value
0&~1 + .9 x 9370 BTU/KWH x 2,789 mills/MMBTU = 38.57 mills/KWH
O&M = 15.05 mills/KWH
In developing the power values which take into account the future
value of fuel, the O&M value will be assumed to represent a fixed annual
charge not subject to increase. Despite the fact that the economic
C-15
analysis for the hydro project spans 100 years at an interest rate of
6-5/8 percent, the projected fuel cost will be based on the price that
can be anticipated midway through the 30-year life of the diesel plant
alternative. Thus, since it is anticipated that the Valdez projects
could have power on line by 1985, the January 1978 value of the dis-
tillate fuel will be based on a present worth year 2000 fuel value. The
energy value will be based on the FERC fuel value of $0.385/gal pro-
jected forward at a reasonable annual compound rate, and then present
worthed back to the January 1978 base date at 6-5/8 percent. While it
has been established that area fuel rates have witnessed a 16 percent
per annum increase since 1971 the continuation of this trend is not
considered realistic. The annual rate increase of 8.7 percent which
has been experienced over the past 10-year period would appear more
reasonable. Therefore, a real dollar value (the difference between the
annual growth rate and the amortization rate) annual increase is esti-
mated to be 2 percent. This results in a January 1978 value of $0.385/
gal fuel projected forward to 2000 .at 8-5/8 percent of $0.595/gal.
This equates to $4.312/MMBTU, which including the cost of O&M, results
in an energy value of 51.41 mills/KWH. FERC includes in the capacity
value a fixed fuel component of total annual fuel consumption of 10
percent for a 50 percent plant factor. Thus, the capacity value is
adjusted as follows:
Adjusted capacity value = $102.69 + 0.1 x .50 x 8,760 hours x
8,200 BTU/KWH x ($4.312/MMBTU -$2.789/MMBTU).
Adjusted capacity value= $108.94/KW -Federal Financing
Similar calculations were done for the 1 percent and 3 percent real
value increase in the cost of fuel. The following is a comparison of
the Federal and Rural Electric Association (REA} financed power values
to be used in the economic assessment of the recommended plans of develop-
ment.
Valdez Area Power Values
REA Federal
Dependable Usable Dependable Usable
Ca~acit~ En erg~ Ca2acit~ Energy
$/KW-yr Mills/KWH $/KW-yr Mi 11 s/ KWH
FERC 109.02 38.57 102.69 38.57 FERC + 1% Fuel Adjustment 111.82 44.33 105.49 44.33 FERC + 2% Fue 1 Adjustment 115. 27 51.41 108.94 51 . 41
FERC + 3% Fuel Adjustment 119. 50 60.11 113.17 60.11
C-16
This analysis is constdered to be conservative since the Federal
Power Corrmission {FPC) now FERC, completed a Draft Environmental Impact
Statement on the Solomon Gulch Project, July 1977, {See Table C-2)
which used an analysis displacing the cost of diesel generation esca-
lated at 3 percent per year. In consonance with this analysis the 15
year power study, November 1976 done by Robert Retherford Associates
uses 7 percent per year to escalate the cost of fuel. It is readily
appare~nt that in both a private firm and the Federal agency which pro-
vides the Corps with power values, there is a discrepancy in the manner
they are derived. Therefore, we will continue to be conservative and
assume that the 3 percent cost escalation will be used to derive the
benefits.
C-17
HYDROELECTRIC ALTERNATIVES IN THE VALDEZ AREA
ALLISON CREEK
Lake Tap:
This scheme would involve a lake tap and a tunnel with a penstock
in it. The storage reservoir would be operated from the natural lake
outlet elevation of 1,367 feet and fluctuate down to the 1,267 foot
elevation with a total storage capacity of 20,678 acre-feet. The prime
energy, average annual energy, installed capacity, and annual cost for
this scheme are shown below.
Average
Prime Annual Installed Annual
Elevation EnerJy Energy Capacity Cost
(Feet) (MWH (MWH) (KW) ($1,000)
1,367 33,116 35,749 7,560 2,712
SOLOMON GULCH
The scheme which was looked at for this location was a 115 foot high
concrete gravity dam with three small adjacent rockfilled dams. The
spillway would be included in the concrete gravity dam with a crest of
665 feet. The power pool would operate between the 685 and 631 foot
elevation with a storage of 25,650 acre-feet. The transmission line
would be about 9 miles long. The prime energy, average annual energy,
installed capacity, and annual cost for this scheme are shown below.
Average
Prime Annual Insta 11 ed Annual
Elevation Energy Energy Capacity Cost
{Feet} (MWH) (MWH) (KW} ($1,000)
685 28,502 40,780 6,200 2,450
BENEFITS
The benefits claimed for the two projects of Solomon Gulch and Allison
Creek (Lake Tap) are solely based on the revenue derived by the sale of
hy~ropower. The following is a tabulation of the dependable capacity,
pr1me energy, and average annual energy for both Allison and Solomon
Gulch.
C-18
Solomon Gulch
Allison Creek-Lake Tap
Dependable
Capacity
(KW)
6,200
7,560
Prime
Energy
(MWH)
28,502
33,116
Average
Annual
Energy
(MWH)
40,780
35,749
The one FERC value and three fuel adjusted power values for both
REA financing and Federal financing were used to analyze the benefits
for each project.
In both projects the benefits for firm energy and the full benefits
for average annual energy were analyzed. The tabulation below shows
the benefits for dependable capacity + prime, dependable capacity +
prime + one-half value for secondary and dependable capacity + full value
for average annual energy.
ANNUAL BENEFITS ;_ <
Solomon Gulch REA Financing (6.4%)
(Annual Cost $2,712,399}
FERC
FERC + 1%
FERC + 2%
FERC + 3%
Allison
Capacity
& Prime
Energy
($1000)
1 '776
1 '956
2' 181
2,455
Capacity
Prime & 1/2
Secondary
Energy
($1000)
2,013
2,230
2,496
2,824
(Annual Cost $2,450,285}
FERC 2 '1 02 2' 152
FERC + 1% 2' 314 2,372
FERC + 2% 2,574 2,642
FERC + 3% 2,894 2,973
CONCLUSIONS
Capacity
& Average
Annual
Energy
($1000)
2,250
2,502
2,812
3,193
2,203
2,430
2,709
3,052
Federal Financing (6.625%)
Capacity
& Prime
Energy
($1000)
1,737
1 '918
2 '141
2,416
2,054
2,266
2,526
2,846
Capacity
Prime & 1/2
Secondary
Energy
($1000)
Capacity
& Average
Annual
Energy
($1000)
1,973 2,210
2,190 2,463
2,457 2,773
2,785 3,154
2,105 2,155
2,324 2,382
2,594 2,662
2,925 3,005
As was indicated before that the 3 percent escalation values would
be conservative and we will use those to analyze the two projects.
Utilizing the REA financing, 3 percent fuel escalation and full value
for the average annual energy the average annual benefits for Solomon
C-19
Gulch and Allison Creek are $3,193,000 and $3,052,000 respectively. It
seems valid to take full value for the average annual energy since in
all likelihood the 2,800 KW mobile gas turbine in Valdez presently would
be moved to Glennallen and the projected need in Valdez would be about
41,400 MWH in 1985 (the projected power~on-1ine date). The maximum
average annual energy (35,749 MWH) which would be produced by Allison
Creek would leave 5,651 MWH to be produced by the existing diesel units.
Since Allison Creek has a higher percentage of its average annual energy
as firm energy and it also has a larger quantity (33,116 MWH as compared
to Solomons 28,502 r1WH), it would seem that Allison Creek would be the
slightly better project.
If CVEA develops Solomon Gulch it would provide a large portion of
the energy required by Valdez with some supplemental diesel generation.
Within the CVEA plan there are provisions to include an intertie with
Glennallen. This intertie would open up a new market and increase the
required energy required by the system as indicated by Graph C-2.
It is apparent that without private development there would be a
definite need for energy in the immediate Valdez area. If there is
private development it also appears that the expanded market {including
Glennallen) would have a large enough demand {99 x 106 KWH in 1985} to
absorb all the energy generated by both Solomon Gulch and Allison Creek.
C-20
n
I
N .....
"' ""'$
OJ
"0 :::::;
n
I
PROJECTED VALDEZ ENERGY DEMAND
0:::
:J:
!\::
::::s::::
z
0
:::i
-1 -~
> C!J
0:: w z w
YEAR
DEVELOPED BY ROBERT W. RETHERFORD ASSOCIATES NOV. 1976 1
-en en -
0 en en -
en
00 en -c:a
00 """' 00 en en -.... ::a
C)
""' z: 00 en .... en .... ..,_
U) ell: -00 u en .... C) en en
ell:
11'1
00 ca en .... a:
C) ....
"" a:
00 a: ....
en :z: -c:c ..,_ .... ..... a:
M >-a: 00 en -..,_
a:
N .... m 00 C) en a: ....
>-.... m
00' en ca -.... a.
C)
0 ....
00 ....
en =--....
Cl
en
""' en -
00
""' en -
""' ""' en ....
HHM>I NOillll A9HiNi
C-22 Graph C-2
.ll
1J
l.!!J
l'.1!>le S-1
£coi".Otni-: Co'J'!yd.!:'i.llon of Solono:>n C·..:l..:h 1:to:,eet. anL Rc.:tso:o.abla Alt.::m.:.:Ci•:;~!\1
Ite:n I lli ?:-.:--.. "":t Transmi>1sior. ,.,inc I ~evelov~e~;,t . <-~e
"..'alCti!z _c·wer..?.l:.~~
' i Ir.!l't~l\•d C'lpAtlty (<;.:) I 12' ~00 12,000 27,000 I
'
c~~ltd Costs ( $1. coo. 000) l I I -i l
,) Gtnt!r&ti!1~ Plr.nt ll. 50' t3. 503 I 6;..496 ' I I
~~ Su?sta~io~s l. 00 Lon s.co ! :
c: tr•!'l~,;d.s.:ion Lint• 15. 6J 31,)42 !
Capital Cost.s C;oo'!rating
...L _[
Pl•nt only (~/<.•) 1087 .H 1087. 7J 2277. 63 .. ! ~ J ... ~
Esti':':'.att!d Av.n:2.;::: A:-.:w.ll " -+-"
lJ 8
t
, i C•~·•rt.t1M (1r.f.o) 52.680
u
54,565 llot,606 c I
F lx~cl a-.. ,r ... u "' 0 ::: -;
(perce;>t} ........
I ::: ~· ::-; -· I '"I G<'ft4U'b& PlAnt 6. 54 6.,. 6,54
.,
II lv»iltaUol'l I 7.JU 7. HZ 7.J22 .. .., .... ~
e trau~:~iul<·ft Ur.u 7.182 g ll "' ~ I 7.182 ""' ~ .. u u
Annu•l O&.'i +A&G ($1,000)
< ... < -I ..
e) Cenero~otlng Plant 205. 33 205.13
... "' I
250.10 ::. I
, I t,'1 SIJ'>st:~ti·~nl' 49.02 16.34 134.00 ;..
c:) Tctr.st'llsslon Line• 50.11 72.27 I
Tntol Annu.t Co•t(Sl,OOO,r. 3) 2.4S5 1. 151 7. 106
Tor.l Cnot (!-11 H ,./;.' • .,)
46.60 I J lq16 21.10 50.18 45. 1 .;1. 7
19~0-1010 .1\'•t•·~' Fu•l
&11-plllt'"!:ft,.itt (Drrrr~la/y~u 96,900 94,000 217,614
D•t• ot Fu1l Hyrlro
l/t11inti>n 19EO 1983 1991
50 yr. :'.~. t."~veii1.~d I I
A.."til\:tt l':-v1t"ct C::-st
($/}'<;.<) 2,570,600 1,)56,300 7,))),800
~0 yr. P.W. Lev•lir.~i!d l Volut of Dh1>h<ed 5,048,80' 1 Oh .. t C•n.rotion ($/yur} l, )44 ,700 9,738,600
5J yr. P.ll. l.•v•Hnd
At>nuol leneflt ($/~ur) 2,478, 200 t,9es,4oo 2,405,000 I
J Capital costa are mid· 1976 level and include interest during construction, 5.424~ annual rate.
n The proposed project AVerage annual generation available ia approximately 2,000 MWh lese than
the no-transmission alternative because that amount of energy will be used to heat the tranamiaeion
line in Thompson Pasa to prevent ice build up.
Jl Fixed charges: (in percent)
ltelll
Coat of money
Depreciation
Interim replacement&
Fed. Kiac. Tax
Insurance
Total
Hydro
S.424
.416
.40
.10
~
6.540
];ransmisaion
S.424
1.398
.10
.10
_.J.L
7.182
S!,!batation
.5.424
1.398
.35
.10
-:1L
7 • .522
~ 06M +A~ are operation, maintenance, administration and general expense• baa~d on national
averages aa of mid-1976.
JJ Total annual project coat (1976 level} divided by the eatimated average annual generation.
JU Average amount of fuel which would be offset in the period 1980-2030 by hydro-energy that
can ba produced and used in Applicant'• ayatem,
~ The year when the projected loada would utilize all of the avernge annual anergy produced by
the project or alternatives.
JJ Includee 061'1 and A~ coats escalated at 6~ per year.
JJ The levelized value of diesel generation to be displaced by the hydro project baaed on predicted
anergy need growth on Applicant' a ayatem and the coat of diesel generation escalated at 31 per year,
\2) Thia h the difference between .aJ and j.J and represent• the dollar savinga to be realized by
uain& hydro generation rather than continued dieael generation.
C-23 Table C-2
SECTION D
ANALYSIS OF THE AREA ECONOf~Y
SECTION 0
ANALYSIS OF THE AREA ECONOMY
TABLE OF CONTENTS
ITEM
GENERAL
Fisheries
Recreation & Tourism
Transportation
Conclusions
PAGE
D-1
D-1
0-1
0-1
D-1
ANALYSIS OF THE AREA ECONOMY
GENERAL
At present the Valdez area is undergoing a major adjustment as they
make the transition from a crash construction period to a new norm that
will be described by the operation, maintenance, and supervision of the
oil terminal. Oil first entered the pipeline on June 20 at Pump Station
1. The first tanker load of oil departed Valdez terminals August 1,
1977 and a total of 158 tankers carrying just over 100 million barrels
of oil had departed by December 31, 1977.
While the oil industry with its normal support activity will pro-
vide the base for the area economy, the development of existing natural
resources will continue and no doubt be enhanced by the addition of new
techniques, new people, and new financial resources.
Fisheries:
With the development of a new boat harbor and additional people,
there will be a renewed interest in both commercial and sports fishing.
The State's salmon hatchery program designed to support and increase
the salmon harvest, the establishment of the 200 mile management zone,
and the expanded sports fisheries activity of Prince William Sound all
amount to increased activity in the local fishing industry.
Recreation & Tourism:
The newly established ferry terminal at Valdez has been the focal
point for workers and vacationers who make the trip by auto from Anchorage
to Valdez by road and return by ferry via Whittier. With the addition
of the Pipeline Terminal and the influx of new people, there will be a
steady growth in the Valdez tourist trade.
Transportation:
With increasing activity and development of interior Alaska, there
is a very real possibility that truck and van traffic will be developed
from containerized storage yards in Valdez. This traffic to date has
amounted to fuel oil and pipeline equipment and limited general freight
but depending on future interior development, could develop into a route
for general freight to interior Alaska.
Conclusion:
In general the basic elements of the area econo!llY, i.e., transpor-
tation, resource development, construction, recreation, and services
should experience a steady growth pattern through the economic life of
the proposed project.
D-1
SECTION E
REGIONAL GEOLOGY
Item
INTRODUCTION
SOLOMON GULCH DAt1SITE
Geology
Surficial Deposits
Seismicity
Construction Materials
ALLISON CREEK DAMSITE
Geology
Surficial Deposits
ALLISON CREEK -LAKE TAP
Seismicity
CONCLUSION
SECTION E
REGIONAL GEOLOGY
TABLE OF CONTENTS
Page
E-1
E-2
E-2
E-2
E-3
E-3
E-4
E-4
E-4
E-5
E-5
E-6
INTRODUCTION
The only sites that appeared to be economically feasible during the
initial screening were Allison Creek and Solomon Qulch. Since these
were the only sites which seem viable, it was only reasonable to make
onsite visits of the two which seemed feasible.
E-1
SOLOMON GULCH DAMSITE
Solomon Lake, is located in a high-level valley near the head of
Valdez Fiord. The valley is a glacially modified feature with a gentle
gradient from it's head to a point approximately 3,700 feet from tide-
water. At this point, a natural rock barrier runs transversely across
the valley; beyond this barrier, the valley floor drops precipituously
some 625 feet to tidewater. The rock barrier in the form of a group of
rock hills forms a natural dam for the lake. In past geologic history,
Solomon Creek appears to have crossed this dam at several locations,
but it is presently entrenched in a V-shaped notch adjacent to the west
side of the valley floor. Within this incised canyon, an old low con-
crete dam maintains the present level of the lake. Below the dam, the
stream descends in a series of cascades, waterfalls, and rapids to
tidewater.
Bedrock at the damsite is a dark grey argillite which has been sub-
jected to silicification. Because of this silicious content, and the
resulting resistance of the rock to erosion, a rock ridge has remained
running transversely across the valley as the less resistant rock on
either side has eroded away. Quartz stringers have filled the joint
openings in the rock making it relatively impervious. Very light wea-
thering is evident on the surface of the ridge and no major imperfections
were observed. It is felt that the rock ridge will provide a highly
suitable foundation for a dam.
GEOLOGY
The surrounding country rock is part of the regional greywacke
complex. The rock which forms the ridge at the lake outlet is an argil-
lite facies of the regional rock, The rock in the vicinity of Solomon
Gulch has well developed bedding striking east-west and dipping steeply
to the north. Major joints oriented perpendicular to the bedding are
visible along the south valley wall of Valdez Fiord. This bedding and
jointing controls the gradient and location of Solomon Creek below the
lake.
SURFICIAL DEPOSITS
Surficial deposits in the valley above Solomon Lake consist primarily
of alluvial and glacial deposits. Materials are silts, sands, and
gravels with gradations varying from the coarser materials at the head
of the valley to a broad silty sandy delta at the upper end of the lake.
Indications are that these deposits extend to a considerable depth.
Below the lake, surficial deposits consist of a rather thin mantle of
unconsolidated sediments with local deeper deposits including some
talus and gravel phases.
E-2
SEISMICITY
The Valdez area is an active seismic area and Solomon Gulch is some
72 kilometers east of the epicenter of the 1964 Earthquake. Seismic
studies will be an important part of predesign investigations and the
design parameters will necessarily include the effects of high inten-
sity shaking.
CONSTRUCTION MATERIALS
Construction materials for an earthfill dam can be obtained from
the alluvial and glacial deposits in the valley on the upstream side
of Solomon lake. A haul road around the lake, approximately 1-l/2 to
2 miles long, would be required to reach the coarser gravels for the
embankment shells. The finer materials for the embankment core can be
obtained from the delta immediately above the lake. Filter materials
can be processed from the upstream deposits. It is also highly prob-
able that these deposits could be utilized to provide concrete aggregates,
although the absence of deleterious materials would have to be verified.
Riprap and rockfill materials can likewise be obtained close at
hand. A quarry can be developed in one of two locations, both of which
are convenient to the site. The recommended site is on the right canyon
wall downstream of the transverse ridge which would support the dams.
The alternate quarry site is located on the downhill side of the trans-
verse ridge between the two sections of the dam. Field studies and
core drilling will be necessary to verify the ability of these sites to
produce stone of the sizes required but no problems are anticipated
related to either stone size or quality.
E-3
ALLISON CREEK DAMSITE
Allison Lake, is located in a glacial valley along the south shore
of Valdez Fiord approximately 2-1/2 miles west of Solomon Gulch. The
outlet creek flows into the harbor area at the entrance to the Alyeska
tank farm. The lake is at elevation 1,367 feet and is the result of
ponding behind a terminal moraine deposit of large boulders and various
finer deposits. Through this moraine, the outlet creek has eroded the
present channel. Soundings taken on the lake were moderately shallow
except in one area towards the head of the lake where a depth of over
160 feet was recorded. Surficial evidence suggests that as the glacier
receeded, it no longer carried sufficient rock debris on its surface
to fill the valley. Thus, the moraine 11 feathered out 11 from the main
deposit near the valley mouth down to the bedrock valley floor where
the deep soundings were taken. This concept would indicate that the
moraine deposits empounding the lake are probable very deep at least
in the order of several tens of feet.
GEOLOGY
Geology of the Allison Lake area has been described under a similar
heading for Solomon Creek.
SURFICIAL DEPOSITS
The valley in which Allison Creek is located is much shorter than
the one at Solomon Creek. As a result, there is a distinct absence of
the abundant deposits of gravels and silt which characterized the valley
above Solomon Lake. Below Allison Lake, the terminal moraine extends
across the valley floor in two distinct ridges. The main ridges are
several hundred feet wide. The entire moraine is a mixture of materials
varying from fine grained silty materials to huge boulders as large as
a small room.
A low dam has been considered for Allison Lake, to be constructed
across the valley in the area now covered with the morainal deposits.
As previously mentioned, these deposits are probably several tens of
feet in thickness and may be very porous in areas where boulders are
the dominant material. It is highly improbable that this morainal
material could be used as a dam foundation. Even after an expensive
and extensive exploration program, the risk of porous zones and the
expense of providing a cut-off wall would suggest complete removal of
the moraine to bedrock as the only viable alternative. Even if the
morainal deposits could be left in place, an overflow spillway and out-
let feature would have to be cut into the bedrock of the valley wall
at considerable expense. In general, Allison Lake is not considered
to be a suitable damsite due to the obvious expense which would be
entailed in the construction of a dam at this site.
E-4
ALLISON CREEK -LAKE TAP
Although a dam is not considered feasible at Allison Creek, a lake
tap is considered a viable alternative. Bedrock in this area is, as
previously noted, a graywarke complex which has been subjected to sili-
fication to some degree. The lake tap planned would be approximately
100 feet deep with a tunnel 8,100 feet long.
From information known to date (1978) there is no adverse geologic
features that would make the tunnel unfeasible to construct. The lake
tap will require an area of shallow sediment and sound bedrock reason-
ably free of fractures. Highly specialized and exacting explorations
are required for locating a tap area. Also, some four or five holes
will be required to explore along the tunnel alinement.
SEISMICITY
Seismicity of the area has been discussed under "Solomon Lake Dam"
heading. One additional feature relating to Allison Creek is noted.
The proximity of the Alyeska tank farm to the outlet to Allison Lake
would probably result in the need for extremely conservative design
criteria and added construction costs.
E-5
CONCLUSION
The study will require drilling holes at the Allison Lake tap site,
which will begin in Stage II and be included in the feasibility report.
The geology of Allison Creek and the conservative design criteria may
increase the cost to the point where the project may not be economically
feasible.
E-6
SECTION F
ENVIRONMENTAL ASSESSMENT
SECTION F
ENVIRONMENTAL ASSESSr1ENT
TABLE OF CONTENTS
Item
INTRODUCTION
EXISTING ENVIRONMENTAL SETTING
Physical Setting
General Description
Geology and Topography
Climate
Water and Air Quality
Esthetics
Biological Setting
Vegetation
Mammals
Birds
Fish
Threatened or Endangered Species
Social, Economic, and Cultural Setting
Archeological and Historic Resources
Economy of the Area
Land Use Plans
Description of the Alternatives
Solomon Gulch
Allison Creek
Diesel
No Action
PROBABLE IMPACTS
Solomon Gulch
Physical Impacts
Water and Air Quality
Esthetics
Biological Impacts
Vegetation
Mammals
Birds
Fish
Threatened or Endangered Species
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Item
TABLE OF CONTENTS (cant)
Social, Economic, and Cultural Impacts
Archeological and Historic Resources
EconomY of the Area
Allison Creek
Physical Impacts
Water and Air Quality
Esthetics
Biological Impacts
Vegetation
t1amma 1 s
Birds
Fish
Threatened or Endangered Species
Social, Economic, and Cultural Impacts
Archeological and Historic Resources
Economy of the Area
Diesel
General Impacts
No Action
General Impacts
COORDINATION t~ITH FISH AND \~ILDLIFE SERVICE
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INTRODUCTION
This environmental assessment for the Valdez, Alaska Stage II
Checkpoint Report provides a description of the existing environmental
setting of the project area, and a discussion of the probable environ-
mental impacts associated with the major alternatives. Because this
report is in such an early stage much detailed information is lacking.
If the proposed project is authorized for further study more detailed
information will be gathered.
F-1
EXISTING ENVIRONMENTAL SETTING
PHYSICAL SETTING
General Description:
Port Valdez, located in the extreme northwest part of Prince William
Sound, is about 14 miles long and 3 miles wide. Its steep bedrock shore-
lines are broken occasionally by streams descending the steep slopes.
The Lowe River flows into Port Valdez through a delta which extends
completely across the east end of the bay. It was in the center of
this delta that the old town of Valdez was located prior to being largely
destroyed by the 1964 Earthquake. A new town of Valdez has been con-
structed on the delta of Mineral Creek on the north side of the bay.
The west end of the bay is connected to Prince William Sound by the
Valdez Narrows which serves the super tanker traffic for the Trans-Alaska
Pipeline Terminus and by the Valdez Arm of the sound. Port Valdez is
the northern most ice-free seaport in Alaska and provides the most
direct route between the sea and interior Alaska.
Both Solomon Lake and Allison Lake are located within the Chugach
Mountain Range near the southern edge of Port Valdez, and are typical
of the glacially carved high, hanging valleys of the area. The valleys
feeding these glacial lakes have gentle gradients and lie in a north-
south trend. Mountains, which are snow capped in winter and glaciated
in summer tower above the east and west sides of the valleys. Creeks
descend steeply to sea level where they enter Port Valdez.
Solomon Lake (elevation 625 feet) is located in the Solomon Gulch
drainage and is about 5.5 miles south of Valdez. The lake is a 100
acre glacier fed reservoir impounded by a small concrete dam. Solomon
Lake is boardered on the east by Sugarloaf Mountain (elevation 3,484
feet) and by an unnamed mountain (elevation 3,786 feet) on the west.
This site was previously used for hydropower production from about 1907
to 1950. Parts of the penstock can still be seen as well as the aban-
doned turbine and generator.
Allison Lake is a natural, glacial lake located about 2 miles south
of the Alyeska Oil Pipeline terminal and Port Valdez and about 2 miles
west of Solomon Gulch. This deep lake, impounded behind a boulder
strewn moraine has a surface elevation of 1,367 feet. The outlet stream
traverses a gentle gradient for approximately 0.6 mile before descending
steeply to sea level about 3.7 miles from Valdez.
F-2
Geology and Topography:
The Chugach Mountain Range is located along the north coast of the
Gulf of Alaska forming a rugged barrier to the interior. Bedrock for-
mations in the Solomon Gulch and Allison Creek areas are of the geologic
series termed the Valdez Group which cons.ists primarily of interbedded
slates and graywackies, argillite and arkosic sandstones with some
igneous intrusions and volcanoes.
Rocks of the area are intensely folded. Foliation strikes east-west
and dips steeply to the north. They are strongly jointed, the most
prominent set being oriented perpendicular to the foliation. Most of
the immediate area's terrain reflects this jointing. The streams on the
southern side of Port Valdez generally parallel Solomon Creek and
Allison Creek, following the major joints in north-south trends. Re-
peated intense glaciation has occurred, resulting in unconsolidated
superficial deposits overlying bedrock formations.
The areas studied lie within one of the worlds most active seismic
zones. Approximately 70 earthquakes of estimated or recorded magnitudes
of 5 or greater on the Richter scale have been reported from Valdez since
1898. Between the years of 1899 and 1965, seven earthquakes have equalled
or exceeded a magnitude of 8 on the Richter scale. There is no evidence
of significant ground displacements in the damsite area since late Eocene
or Oligocene time 25 to 40 million years ago. There is no record of
direct earthquake damage to any structure located on bedrock in the
Prince William Sound area.
Seismic sea waves and local waves caused by submarine slides of
deltic deposits have caused extensive damage around the Port of Valdez.
Local waves near the mouths of Solomon Gulch and Allison Creek have
reached heights of 30-40 feet. Although these waves would have no
effect on the lakes, they would affect powerhouses located at the base
of the cliffs for both locations.
Climate:
The terrain surrounding Valdez exerts a pronounced influence on
practically all aspects of the local weather and climate. The shel-
tering effects of surrounding mountains funnel local winds into two
distinct channels. From October through March or April prevailing winds
are from the northeast; the rest of the year prevailing winds are from
the southwest. Maximum sustained winds at 58 mph and gusts of 115 mph
have been recorded at Valdez. The average annual temperature at sea
level in the Valdez area ranges from 39° F to 43° F, with a recorded
maximum of 87° F and a minimum of minus 28° F. The average annual pre-
cipitation is 59.31 inches including 244 inches of snow.
F-3
Water and Air Quality:
Because of limited human activity in the Solomon Gulch and Allison
Lake areas, the quality of water and air resources is relatively high.
Typical of most glacial streams Solomon Gulch and Allison Creek have
a milky color and during periods of high flows carry a heavy silt load.
There are no air quality monitoring sites within or near either of these
areas.
Esthetics:
Scenic value and natural beauty abound in the largely undeveloped
project area. The project area ranks high in all elements of esthetic
quality including: vividness, visual intactness, unity, and visual
uniqueness.
The Solomon Lake area shows some evidence of man's past activities,
but the upper drainage area retains much of its pristine character.
The lake itself is manmade, and parts of the old hydropower facilities
remain. Some mining activity occurred near Solomon Gulch above the
lake and remnants of aerial tram supports, other mine structures, and
tailings are still evident. The valley walls surrounding Solomon Lake
rise abruptly, ascending to Sugarloaf Mountain (3,484 feet) on the east.
Solomon Gulch extends about 7 miles upstream from the lake to its glacial
headwaters. Below the lake the creek cascades to Port Valdez in less
than 1 mile. Towards its lower end, the creek is crossed by the access
road which follows the buried oil pipeline and by the Dayville road
adjacent to Port Valdez.
There is virtually no sign of human activity in the Allison Lake
area. The valley walls rise steeply above the lake and upper Allison
Creek to a height of about 3,500 to 4,000 feet. Below the lake, Allison
Creek descends rapidly to Port Valdez, about 2-l/2 stream miles distant.
At its lower end the creek enters Alyeska Pipeline Service Company
lands associated with the pipeline terminus. The pipeline is buried
under the creek in this area. Near its mouth the creek is crossed by
Dayville road.
BIOLOGICAL SETTING
Vegetation:
The coastal region surrounding the proposed project area is typified
by dense, coniferous forests of Sitka spruce and western hemlock with
an understory of alder and other shrubs. The steep slopes surrounding
the lakes support tall shrub thickets consisting primarily of alder.
Also present are salmonberry, blueberry, and devils club. The alluvial
plains above the lakes support willow and a few cottonwoods. At higher
elevations the shrub thickets give way to alpine tundra.
F-4
Detailed information concerning wetlands in the area is lacking,
however, wetlands occur at the head of Solomon Lake and in the Lowe
River delta. DraftER 1105-2-XXX, l Oct 77 directs that 11 Since much
~f the wet~and_analyses depends on the final selection of a plan and
1ts a~thor1zat1on by Congress, and t~e identification of specific
locat1ons of plan features, the Sect1on 404 evaluation cannot be com-
pleted until the advance engineering and design stage is underway or
completed."
Mammals:
Species of wildlife known to occur in the proposed project area
include the brown/grizzly bear, black bear, mountain goat, wolf, wol-
verine, martin, porcupine, snowshoe hare, and others, however the
densities of the respective populations is unknown. There is little
information on small mammals present in the project area although lists
of species are available for the Valdez area.
A small population of brown/grizzly bears occurs within Solomon
Gulch. The scarcity of the tundra and open grassland habitats favored
by the species, could account for their small numbers. Relatively good
black bear habitat occurs in strips of land from the alpine zone to the
tidal region. These areas support fruit-bearing shrubs, herbs, and
grasses that comprise the bears diet. In addition, the estuarine areas
of Solomon Gulch provide a seasonal supply of salmon for the black bear.
The low growing alpine vegetation on the mountian slopes rising above
Solomon Lake provides habitat for mountain goats. ADF&G has found this
habitat to be 11 marginal 11 and goat numbers limited by winter snow depth.
Wolves are known to inhabit coastal regions of the State, however, popu-
lations are subject to significant local fluctuations in r~sponse to
prey availability, historic preditor control, and hunting pressures.
Birds:
Waterfowl use of the project area is probably quite limited. The
lakes may occasionally be used for resting, and feeding may occur in
the shallow, upper parts and along the braided stream channels. Exten-
sive waterfowl use is made of the intertidal area around upper Port
Valdez and the Lowe River delta. Waterfowl present year round include
seaters, goldeneyes, eiders, mergansers, mallards, and Canada geese.
Birds seasonally present include pintails, teals, widgeons, and shovelers.
Sea birds inhabiting the area include gulls, Arctic terns, kittiewakes,
murres, murrelets, auklets, pelagic cormorants, and guillemots.
Upland game birds which inhabit the area include willow, rock and
white-tailed ptarmigans, and the spruce grouse.
F-5
Northern bald eagles are co~non in the Valdez area and several
active nests are present near the Dayville Road at the upper end of
Port Valdez in the Lowe River delta. The eagles congregate at the mouths
of the Lowe River and other streams which flow into Port Valdez to feed
on fish. Other raptors found in the general Valdez area include the
osprey, red-tailed hawk, sharp-shinned hawk, goshawk, and peregrine
falcon.
Fish:
Approximately the lower one-quarter of Allison Creek below the lake
is suitable fish habitat. An estimated 500 pink salmon and 700 chum
salmon spawn in this area. Above this they are blocked by the steep-
ening stream gradient. Dolly Varden and sculpin also occur in the
lower stream reach. No fish are known to occur in Allison Lake. The
transmission line would cross the delta of the Lowe River. This river
supports Dolly Varden and runs of chum, pink, sockeye, and coho salmon.
An estimated 100 to 200 pink salmon and a small number of chum
salmon spawn in the extreme lower portion of Solomon Gulch within the
intertidal area. Additionally, a few Dolly Varden and sculpin are
present. Fish passage is blocked about 100 yards upstream from the
mouth by a waterfall. No fish are known to occur further upstream nor
in Solomon Lake.
Threatened or Endangered Species:
Peregrine falcons have been observed in the general project area
during migration, however, no peregrine eyries are presently known.
Peregrines commonly nest in cliff sites, but occasionally nest on slopes
and river cut banks, mounds, flat bogs, and plains. Such sites occur
near the proposed project along with sources of the peregrine's prin-
ciple food items such passerine birds, waterfowl, and shorebirds.
Several species of wildlife considered threatened or endangered in
the lower 48 states have populations within the project area. These
include the American bald eagle, wolf, and brown/grizzly bear.
No threatened or endangered species of plants have been recorded in
the project area.
SOCIAL, ECONOMIC, AND CULTURAL SETTING
Archeological and Historic Resources:
The Port of Valdez was named in 1790 by its Spanish discoverer Don
Salvador Fidalgo in honor or Antonio Valdez Basan a celebrated 18th
Century Spanish Naval Officer. With the advent of the gold rush of
F-6
1897, the town of Valdez was established as a port of entry to the
Copper River Valley and the Alaskan interior.
Copper was first discovered in the early 19oo•s within the upper
reaches of Solomon Gulch. Mining of this copper ore by Midas Mine began
in 1915 and was accomplished with the use of a 5-mile aerial tramway
which transported ore from the mine to a bunker located on the shore
of Port Valdez. From there the ore was taken by ship to a smelter at
Anyex, British Columbia. In 1920, the unavailability of ships to carry
the ore south forced the mine to close. It was never reopened. Remnants
of the aerial tramway still remain.
Potential use of Solomon Gulch as a hydropower site was realized
and the existing concrete dam and a small powerhouse near the tidewater
were built in 1907. A few years later an additional powerhouse was
built on the right bank of the creek a short distance below the dam
which remained operational until 1943. The tidewater powerhouse ceased
operation in 1950. The dam and remnants of the powerhouses are evident.
The rugged terrain surrounding Allison Lake combined with the lack
of vegetation around the lake provide little encouragement for human
habitation past or present. For this reason archeological potential
is low in this area.
There are no known archeological or historic sites within the pro-
posed project area presently included in the National Register, however,
the Midas Mine is of historical interest.
Economy of the Area:
For a complete discussion of the area economy see Appendix I, Section
D, .. Analysis of Area Economy. 11
Land Use Plans:
The majority of the lands in the proposed project area are publicly
owned, and are administered by either the State of Alaska, the U.S.
Bureau of Land Mangement, or the U.S. Forest Service. The Solomon Gulch
and Allison Lake sites have been withdrawn for future hydropower develop-
ment.
DESCRIPTION OF THE ALTERNATIVES
Solomon Gulch:
Solomon Lake is located about 3/4 mile south of Port Valdez at an
elevation of 625 feet. Currently a small concrete dam impounds a 100
acre glacial fed reservoir which was utilized for hydropower production
until 1950.
F-7
The proposed project would include a 115-foot high concrete gravity
dam located at the existing damsite. An auxiliary dike would also be
constructed across a low area approximately 1,250 feet southeast of the
main dam. Construction of this dam and dike would inundate approximately
760 acres during maximum flood stages. Water from the lake would be
conveyed from the intake structure at the dam to the powerhouse near
the shore of Port Valdez, a distance of 3,645 feet, by a penstock
mounted above ground. In addition, approximately 4 cfs of water will
be released from the dam to maintain water flow within Solomon Gulch
below the dam. Transmission lines would follow existing roads for about
9 miles to Valdez. No permanent facilities to house personnel will be
constructed on site.
Allison Creek:
Allison Creek is located approximately 2 miles west of Solomon Gulch.
The glacial formed lake has a surface elevation of 1,367 feet and is
impounded behind a glacial moraine. Because the moraine is not suit-
able for dam construction, a lake tap at the 1,250 foot level is pro-
posed for hydropower development. This will involve the construction
of a 8,100-foot long tunnel to facilitate a 36-inch penstock which will
convey water from the lake to the powerhouse near the shore of the Port
of Valdez, a distance of approximately 2 miles. There would be no
increase in lake size but Allison Lake would be subject to drawdown up
to 100 feet during operation in the winter. A 6-inch outlet works
approximately 200 feet upstream from the powerhouse would divert a 4
cfs water flow into the natural channel of the lower reaches of Allison
Creek. Transmission lines would follow existing roads for about 10.5
miles to Valdez. No permanent facilities to house personnel will be
constructed on site.
Diesel :
The present power system in the Valdez area utilizes diesel gener-
ators. At the current rate of growth increased demands of electrical
consumption will soon surpass present generating capacity.
Diesel generation could be added in a number of ways including
piecemeal installation of units at numerous locations.
Power costs to the consumer would be increasingly dependent upon
diesel oil prices and the relatively higher maintenance costs of diesel
units. Although oil has provided low cost power benefits for the
Valdez area, the national and international energy crisis has and will
in all probability result in increased prices in the future for this
nonrenewable resource.
F-8
No Action:
Under this alternative no hydropower facilities would be constructed.
Because Valdez is expected to grow, increased power generating capacity
will be needed in the future. for this reason, the no action alterna-
tive is in reality not a true 11 no action" plan because some type of
power generation will be required. Because of the long-time periods
associated with planning, financing, and construction of power gener-
ating facilities it is essential to achieve increased power capacity
long before it is actually needed.
F-9
PROBABLE IMPACTS
SOLOMON GULCH
Physical Impacts:
Water and Air Quality: Selection of this alternative will result
in the temporary, minor degradation of local water and air quality.
Suspended solids, turbidity levels, and stream siltation are expected
to increase as a result of construction related activities. Dissolved
oxygen and dissolved nitrogen levels are also expected to increase
although not significantly. Air quality will decrease as a result of
construction related activities. It is expected that any water or air
quality degradation will only be temporary and that it will return to
normal following project construction.
Esthetics: The esthetic quality of the Solomon Gulch area will be
locally degraded if this alternative is selected. Although some of the
area shows signs of mans presence much of the area retains its pristine
character. All aspects of the project will be visible from the air,
however, in light of existing development in the area the esthetic
quality is not expected to be drastically degraded.
Biological Impacts:
Vegetation: Inundation as a result of dam construction will result
in the loss of about 710 acres of vegetation consisting of dense alder
and some willow and cottonwoods. Some wetlands will also be lost by
inundation. In addition, approximately 184 acres of vegetation will be
altered or destroyed as a result of transmission line and access road
construction. To the extent practical the transmission lines will
follow existing transmission line or road corridors. The total amount
of 11 new 11 corridor that would need to be constructed is presently unknown,
however, it is anticipated that new corridor would be less than 1 mile
in length. Cleared vegetation will be disposed of in an environmentally
sound manner and will be kept out of streams and water courses.
Mammals: In addition to direct habitat loss, wildlife populations
will be disrupted during the construction phase of the project. Con-
struction of the penstock following the ground contours may disrupt
pathways of large mammals unless provisions are made in the design to
allow for passage. The entire project would affect approximately 850
acres of existing habitat, however, the effects on wildlife are expected
to be of a temporary nature and minimal in comparison to the surrounding
available habitat.
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Birds: Construction of the hydropower generating facilities are not
expected to significantly impact waterfowl or other birds because their
use of the proposed project site is limited. Construction of the trans-
mission lines, however, has the potential for adversely impacting water-
fowl and bald eagles in the Lowe River delta area. The transmission lines
may pose a hazard to flying birds and could also disturb nesting eagles.
This risk will be minimized to the greatest possible extent by locating
the transmission line so as to avoid interference with known nesting
sites and timing the construction activities so as to avoid nesting
periods.
Fish: Spawning and migration of an estimated 100 to 200 pink salmon
and a small number of chum salmon may be adversely impacted by alteration
of the natural streamflow regimen in the extreme lower portion of Solomon
Gulch. The few Dolly Varden and sculpin which are also present may be
impacted as well. No fish are known to occur upstream of the waterfall
or in Solomon Lake. In addition, transmission line construction may
adversely impact Dolly Varden, and chum, pink, and sockeye salmon runs
in the Lowe River.
Threatened or Endangered Species: No threatened or endangered
species will be affected by the proposed project.
Social, Economic, and Cultural Impacts:
Archeological and Historic Resources: Although there are no
archeological or historic resources in the project area which are
included in the National Register, the Midas Mine may be eligible for
inclusion. Portions of the aerial tramway and the mine itself may be
inundated by rising pool levels.
Economy of the Area: The basic elements of the area economy (i.e.,
fisheries, recreation, tourism, and resource development) will continue
to experience a steady growth pattern. These elements will not be
adversely impacted by the proposed project but will benefit from it in
that low-cost, clean power will be made available.
ALLISON CREEK
Physical Impacts:
Water and Air Quality: The water and air quality impacts for this
alternative are essentially the same as for the Solomon Gulch alterna-
tive.
Esthetics: The esthetic quality of the Allison Creek area will be
locally degraded if this alternati~e is selected .. All a~pects o~ ~he
project will be visible from the a1r and some port1ons w1ll be v1s1ble
from Port Valdez. Even though the Allison Creek site is virtually
F-11
undisturbed by man the esthetic degradation, when viewed in the context
of the surrounding development and the degree of proposed development,
will be minor in nature.
Biological Impacts:
Vegetation: Some minor losses of vegetation will occur as a result
of this proposal. Vegetation will be destroyed or altered due to con-
struction of a powerhouse (1/2 acre), transmission lines (165 acres),
and access roads (1/4 mile long, 1.4 acres). There will be no vegeta-
tive loss from inundation of lands becaus~ a dam will not be built.
These losses of vegetation are considered to be minimal in light of the
undisturbed surrounding areas.
Mammals: Temporary disturbances of mammal populations will occur
as a result of the construction activities related to this proposal.
In addition, there will be some limited permanent habitat loss. These
impacts are considered to be of an insignificant nature.
Birds: Since use of the Allison Creek area by waterfowl and other
birds is limited, impacts resulting from the selection of this proposal
will be minimized. Waterfowl and bald eagle populations may be adversely
impacted by the transmission lines. Construction activities may disturb
nesting and collisions with the power lines may also occur. Construction
activities will be planned so that any impacts on bald eagle populations
can be minimized.
Fish: Selection of this alternative may result in significant
adverse impacts on the spawning and migration of the estimated 500 pink
salmon and 700 chum salmon which spawn in the lower one-quarter of Allison
Creek. Dolly Varden and sculpin also occur here and may be impacted.
No fish are known to occur in Allison Lake. The transmission lines may
adversely impact the Dolly Varden and chum, pink, and sockeye salmon
runs in the Lowe River.
Threatened or Endangered Soecies: No species currently listed as
threatened or endangered will be affected by the proposed project.
Social, Economic, and Cultural Impacts:
Archeological and Historic Resources: There are presently no known
archeological or historic resources present in the proposed project area.
Econo~ of the Area: Economic impacts resulting from this proposal
are essent1ally the same as those resulting from the Solomon Gulch
alternative.
F-12
DIESEL
General Impacts:
At the present time an assessment of the environmental impacts
associated with the diesel alternative is not possible because specifics
concerning the proposal are lacking. Major air quality degradation
can be expected as a result of combustion byproducts as well as some
local esthetic degradation as a result of plant construction. Biological
impacts are not expected and the social, economic, and cultural impacts
will be much the same as the hydropower alternatives.
NO ACTION
General Impacts:
Probable impacts under this alternative would be the same as those
under the diesel alternative because in reality there is no true "no
action" alternative. Valdez is a growing community needing increased
power capacity in the future. In the absence of hydropower development
some other energy source would be needed. Because technology for energy
sources such as solar power or wind power is limited, diesel generation
would most likely be implemented in the absence of hydropower develop-
ment.
F-13
COORDINATION WITH FISH AND WILDLIFE SERVICE
The draft U.S. Fish and Wildlife Service (fWS) Coordination Act
report is scheduled for submission in November 1978, and their fin a 1
report is due in April 1979. In the interim, a planning aid letter
received in February 1978 contains an extensive listing of mitigation
proposals which FWS would like to see incorporated into the final
project plan. Most of these recommendations appear to be reasonable
measures to prevent unnecessary adverse enviornmental impacts. The
feasibility of some of the measures is dependent upon the extent to
which they are compatible with the final design and function of the
project. It is too early in the planning process to specifically
identify mitigation requirements. Every consideration will be given
to FWS concerns as the study progresses.
F-14
SECTION G
TRANSMISSION SYSTEM
TRANSMISSION SYSTEM
GENERAL
The transmission s,ystem will be approximately 9 miles long with a
50 foot right-of-way. The corridor would follow adjacent to the exist-
ing road and terminate at the load center of Valdez. The terrain is
of a moderate rolling mountainous type close to the tidewaters of the
Port of Valdez. The transmission system will be comprised of single
wood poles with six metal towers. The meta.l towers will be utilized
to cross the Lowe River and the maY'sh area next to Valdez.
The transmission system will be analyzed 1n much greater depth in
the feasibility report and pl"ovide a more comprehensive scheme. The
present proposal was only used to provide general guidelines to approxi-
mate a reasonable cost of the system which would be incorporated in the
cost estimate.
G-1
SECTION H
MARKETABILITY ANALYSIS
MARKETABILITY ANALYSIS
GENERAL
The marketability analysis will be conducted by the Alaska Power
Administration (APA) for the feasibility r·eport. The initial contact
has been made with APA and they will provide their portion of the
report as scheduled.
H-1
APPENDIX I
Section
A
B
c
D
E
F
G
H
APPENDIX I
Item
HYDROLOGY
PROJECT DESCRIPTION AND COST ESTIMATES
POWER STUDIES AND ECONOMICS
ANALYSIS OF THE AREA ECONOMY
REGIONAL GEOLOGY
ENVIRONMENTAL ASSESSMENT
TRANSMISSION SYSTEM
MARKETABILITY ANALYSIS
SECTION A
HYDROLOGY
SECTION A
HYDROLOGY
TABLE OF CONTENTS
Item
GENERAL
Basin Description
Streamflows
CLIMATE OF THE AREA
General Description
Temperature
Precipitation
Snow
Wind
Storms
STREAMFLOW RECORDS
Extension of Streamflow Records
Estimated Damsite Streamflows
Sedimentation
Evaporation
STREAMFLOW CHARACTERISTICS
Low Flow Analysis
Flood Characteristics
Past Floods
Flood Frequencies
Probable Maximum Flood
Page
A-1
A-1
A-1
A-4
A-4
A-5
A-6
A-7
A-7
A-8
A-9
A-9
A-10
A-10
A-12
A-13
A-13
A-13
A-13
A-13
A-14
GENERAL
BASIN DESCRIPTION
The study area is within the area of maritime influence which pre-
vails over the coastal areas of southcentral Alaska and is in the path
of most cyclonic storms that cross the Gulf of Alaska. Consequently,
the area has little sunshine, generally moderate temperatures, and
abundant precipitation. In contrast with the characteristic lack of
sunshine, there are intervals of several days' duration, during which
clear skies prevail. The rugged Chugach Mountains exerts a fundamental
influence upon local temperatures and distribution of precipitation,
creating considerable variations in both weather elements within rela-
tively short distances. The sites listed below are shown on the basin
location map. (Figure A-1)
Solomon Creek
Allison Creek
Unnamed Creek
Mineral Creek
lowe River (Keystone Canyon)
STREAMFLOWS
Runoff characteristics of streams in the study area are subject to
maritime influence. This influence greatly increases the runoff per
square mile and also changes the timing of high flood flows from those
experienced in central or interior Alaska. While flood peaks do occur
in ~1ay and June, due to snowmelt runoff, the yearly maximum peaks gen-
erally center around the month of September. Normally about 94 percent
of the annual runoff occurs during the 6-month period from May through
October. In general, there is very little soil over the underlying rock
in the area; hence, the facilities for groundwater storage are exceed-
ingly limited and the major components of runoff are mainly surface flow
coupled with some subsurface or interflow. Therefore, short-duration
dry spells have the effect of generating extremely low streamflow.
Streamflow records were available for Solomon Gulch and lowe River
in the immediate vicinity of the study basin. Another stream, Power
Creek near Cordova, has a much longer record. The streamflows at Power
Creek were correlated with those at both Solomon Gulch and Lowe River
to extend the records. The extended streamflow distributions of Solomon
Gulch and Lowe River along with Power Creek streamflows are shown below.
A-1
STREAMFLOW DISTRIBUTION
MONTH RUNOFF
Lowe Solomon Power
Month River Avera e Gulch Average Creek Average
% Annual cf's mo % Annual· cfs/mo % Annual cfs/mo
Oct 2.6 413 7.0 118 l 0. 6 304
Nov 1.1 190 3.4 59 5.9 173
Dec 0.6 99 1.8 31 2.8 80
Jan 0.4 69 0.9 16 2.0 57
Feb 0.3 59 0.7 14 1.6 51
Mar 0.3 52 0.6 11 1.5 42
Apr 0.3 44 0.8 16 1.6 48
May 3.8 617 8.2 137 6.5 186
Jun 19.6 3,238 21.0 364 14.7 432
Jul 31.7 5,062 24.0 403 19.3 551
Aug 24.3 3,887 17.5 293 17. 1 487
Sep 15.0 2,486 14. 1 246 16.4 481
A-2
MILES
I
GLENNALLEN
LOCATION AND VICINITY MAP
SOUTHCCNTRAL RAILBELT STuDY
VALDEZ INTEHIM
U.S. ARMY ENGINEER OISTHIC\ ALASKA
CORPS OF ENGINEERS
JULY 1977
A-3 Figure A-1
CLlMATE OF THE AREA
GENERAL DESCRIPTION
The study area experiences the same general climate throughout the
south coast region in the Gulf of Alaska. Exposure and topography are
largely accountable for the high precipitation and the mild temperatures
reflect the maritime influences.
Valdez is located on a well sheltered extension of Prince William
Sound. Snow capped mountains containing extensive glacier areas,
surrounding Valdez on three sides, with rugged but unglaciated moun-
tains to the south and southwest. Active glaciers extend to within
5 to 10 miles of old Valdez to the north and reach down to the level of
the glacial plain on which old Valdez is located. This level glacial
plain is a well forested area except for the tidal marshes southwest
and the glacial drainage area to the east. The terrain surrounding
Valdez exerts a pronounced influence on practically all aspects of the
local weather and climate. The sheltering effects of surrounding moun-
tains channel local winds into two distinct channels. From October
through April prevailing winds are from the northeast; from May through
September prevailing winds are from the southwest. Precipitation is
abundant the year round, but builds up noticeably during the late
summer and fall. The heaviest precipitation usually occurs in September
and October, and almost 25 percent of the total annual rainfall occurs
in these 2 months. Snowfall during the winter months is very heavy.
There is considerable cloudiness during the entire year, but slightly
less than is realized at Alaskan points farther southeast. About 1
day in 6 can be classified as clear. Although the high mountain ridges
to the north provide considerable barrier to the flow of cold continental
air from the interior during the winter months, there is a definite off
setting factor in the downslope drainage from the high snowfields and
glacier areas on the southern slopes of these mountains. The lowest
temperatures recorded at Valdez appear to be due to this downslope flow
of cold air, since the lowest temperatures on record have occurred
during periods with little or no wind, providing ideal conditions for
the cold air to flow down onto the flat glacial plain. The nearby snow
and ice fields combine with the ocean areas to provide a moderating
effect on summertime high temperatures which seldom reach the middle
80's. The surrounding mountains tend to produce considerable variations
in practically all weather elements within relatively short distances.
The nearest climatological station with reliable data is located
in Valdez and monitored by the National Weather Service. However,
location and exposure would indicate that the climate in the study area
A-4
would have a somewhat higher total precipitation, less temperature
extremes, and higher total snowfall than the Valdez weather station.
All of the streams in the study are glacially fed and, therefore, con-
tain some glacial sedi.ment.
While the climatic data from the Valdez weather station is fairly
representative of the sea level conditions in the study area, lower
temperatures and greater precipitation will occur over most of the
higher drainage basins. Based on 7 years of streamflow records, which
typify the amount of preci'pi'tation in the areas being studied, the
Solomon Gulch gage recorded an average annual discharge of 104,300
acre-feet for a 19 square mile drainage basin, yeilding a basin average
of 103"inches precipitation per year.
TEMPERATURE
The four climatological stations in the area are located at Copper
Center, Glennallen, Valdez, and Cordova. The records for Glennallen
and Copper Center are incomplete and not presented in this analysis.
A summary of the average monthly temperatures for Valdez and Cordova
are presented below.
AVERAGE MONTHLY TEMPERATURES (OF)
Valdez Cordova
Jan 17.8 23.0
Feb 22.4 26.7
Mar 26.8 29.2
Apr 35.6 36.0
May 43.8 43.7
Jun 51.2 50.4
Jul 53.3 53.4
Aug 52.0 53.0
Sep 46.5 48.0
Oct 37.5 39.6
Nov 26. 1 30.6
Dec 19.5 24.6
The Valdez data is recorded by the National Weather Services at an
elevation of 87 feet mean sea level (MSL). The Cordova data is recorded
by Federal Aviation Agency at an elevation of 41 feet MSL. The temp-
eratures range between 42° F and 60° F during the summer and between
11° F and 43° F during the winter for Valdez with the extremes being
-28° F and 87° F. The temperatures range between 44° F and 61° F during
the summer and between 21° F and 39° F during the winter for Cordova
with the extremes being -23° F and 81° F.
A-5
Both locations averages a growing season of about 4 months. Normally,
the first freeze occurs early in September and the last freeze occurs
in mid-May.
Summertime temperature gradients follow the traditional pattern of
decreasing temperatures with increasing altitude. During periods of
extreme winter cold, however, a strong temperature inversion may exist
in the lower layers of the atmosphere as a result of radiation cooling
and cold air drainage for the surrounding mountains. Under these con-
ditions, the temperature gradient will be reversed.
PRECIPITATION
Precipitation over the basin varies from moderate amounts in the
low elevations to heavy in the mountains. The orographic effect of
the Chugach Mountains insure heavy precipitation in the upper elevations
of the basin and lower amounts in the lower basin. Storms are generally
light in intensity, with few convective-type storms of cloudburst
magnitude.
The only climatological stations in the study area with reasonably
complete precipitation data are located in Valdez and Cordova. Average
monthly precipitation for these communities is presented below.
AVERAGE MONTHLY PRECIPITATION
(inches)
Valdez Cordova
Jan 5.06 6. 14
Feb 5. 30 6.42
Mar 4.33 5.89
Apr 3.06 5.44
~1ay 3.20 5.99
Jun 2.70 4. 67
Jul 4. 31 7.08
Aug 5.80 8.94
Sep 7.74 13. 53
Oct 6.75 12.32
Nov 5.67 8. 37
Dec 5.39 7.45
ANNUAL 59.31 92.26
This data was collected by the National Weather Service and the
Federal Aviation Agency for Valdez and Cordova respectively.
A-6
SNO~J
Snowfall records are not available in the immediate vicinity of the
streams. The recorders in the study basin give an approximate amount
of average snowfall. Snowfall is generally confined to October through
April and comprises approximately 27 percent of the mean annual precipi-
tation.
Snow course data for four stations within the basin are presented in
the following tabulation.
Years of Elevation Average Water
Snow Course Record (ft) MSL Content Per Month
(inches)
March April May
Tsaina River 5 1,500 12. 1 12.9 12.5
Worthington Glacier 19 2,400 15.5 22.2 20.8
Lowe River 4 550 14.0 14.0 11.9
Valdez 4 50 16.0 16.0 13.3
The water content of the May snow mass provides a good index of
expected spring runoff.
WIND
The wind records available are scarce. The National Weather Service
monitors the station in Valdez which has about 3 years of data. Obser-
vations there indicate that the highest winds occur between October and
April. The winds tend to follow the contours of the terrain and, thus,
adjacent areas can have average winds of opposite direction. The follow-
ing is the average fastest 1 minute wind speed for the period of record.
AVERAGE WIND SPEED (MPH)
Jan 23
Feb 25
Mar 25
Apr 25
May 20
Jun 18
Jul 18
Aug 19
Sep 19
Oct 26
Nov 26
Dec 27
A-7
STORMS
Because of the dominating maritime influence, thunder and hail
storms rarely occur in the study area; however, the area is subject
to fall and winter storms of heavy precipitation intensities. These
storms are cyclonic in nature and are generated by the semipermanent,
Aleutian low pressure system. This cyclogenesis takes place as a result
of the cold flow of southeasterly air from Asia, which generates a wave
or the polar front. These storms move eastward from their point of
origin into the Gulf of Alaskat where they cause high winds and low
ceilings for a period of 2 to 3 days. Storms of this nature usually
cause copious amounts of precipitation to fall on the coastal mountain
ranges.
A-8
STREAMFLOW RECORDS
There are two stream gages in the immediate vicinity of Valdez
which have been ga~ed by the U.S. Geological Survey. There is discharge
data for each stat1on and some measurements for chemical constituents
and water temperature. The recorded monthly runoff for Lowe River and
Solomon Gulch are shown on Table A-1.
The gage at Solomon Gulch was on the right bank at the tidewater,
1/2 mile downstream from a small lake and about 3 miles south of Valdez.
The records that are available are July to December 1948 and October
1949 to September 1956. The average annual runoff is 104,300 acre-feet
per year or 144 cfs. The maximum discharge of record is 2,420 cfs on
4 September 1951.
The gage on the Lowe River is located on the left bank 500 feet
south of the south entrance to Richardson Highway tunnel in Keystone
Canyon. The records that are available are October 1974 to the current
year. The average annual runoff is about 1 ,216 cfs. The maximum dis-
charge of record is 12,600 cfs on 11 September 1975.
EXTENSION OF STREAMFLOW RECORDS
Extension of the streamflow records for Solomon Gulch and Lowe River
were performed by linear correlation with the long term records of Power
Creek near Cordova. In an attempt to observe visual relations between
the stations, the respective monthly streamflows for the two stations
were plotted against the correlative Power Creek monthly streamflows,
as shown in Table A-2. Depending on the shapes of the relationships
observed, the data were split into time groups ranging from 1 month to
3 months. After transformation, a linear regression analysis was per-
formed for each data group and, based on the correlation coefficients
and standard errors of estimate, a relationship for each group of data
was adopted for streamflow extension.
In general, there was good correlation for the months of April through
December. The winter months of January, February, and ~1arch were grouped
together and still had a low correlation coefficient. It may be explained
by the low flow characteristics of Power Creek which did not describe
the same low flow on the other two gages. The equation on the Lowe
River for August was adjusted since it was not consistent with the slope
of the two adjacent months of July and September, therefore, no correlation
coefficient was derived. The relationships derived for the two stations
are shown in Table A-3.
The monthly streamflows for the other possible alternatives of
Mineral Creek, Allison Creek, and Unnamed Creek were not correlated with
A-9
Power Creek since there were no records available for them. Since
Solomon Gulch's drainage area of 19.5 square miles approximates the
same size as these possible alternatives~ its streamflow values were
used to derive streamflow values for the alternatives rather than the
Lowe River streamflows with a drainage area of 222 square miles. The
following table lists the pertinent characteristics of each of these
basins.
Area Mean Elevation 5~ Area
Creek (Mi2) (Feet) in Glaciers
Allison 5.68 2,800 24
Mineral 45.3 3,480 30
Power 20.8 2,140 25
Solomon Gulch 19.5 2,300 21
Unnamed 25.2 3, 310 52
The monthly streamflow values for Power Creek were used to extend
the period of record for Solomon Gulch, and this extended period of
record is shown in Table A-4. These values in turn were used along with
a basin area relationship to determine streamflows for those basins
without data. Allison Creek estimated streamflows were derived in this
manner and are shown in Table A-5.
ESTIMATED DAMSITE STREAMFLOWS
It has been assumed that the streamflows determined through the
previous analysis would be the estimated damsite streamflows. The gage
on the Lowe River in Keystone Canyon is approximately where the dam
would be built. No reduction in the streamflow is necessary. The stream
gage on Solomon Gulch is located about 1/2 mile downstream of the pro-
posed damsite and there are no large contributing streams or large
addition of drainage area which would change the streamflows significantly.
Since the streamflows that were computed through the linear correlation
for Solomon Gulch approximated the damsite discharges, the other basins
which utilized the Solomon Gulch streamflows, and the proper ratios will
not be reduced for their damsite streamflows.
SEDIMENTATION
Sediment data for Solomon Gulch or Lowe River was not available at
this time. Since it is a well known fact that both of these rivers do
have a substantial sediment load, it was felt that some means should be
implemented to approximate the load.
Two different, but somewhat similar analysis were used to approxi-
mate the sediment load. The first analysis was taken from "Southcentral
Railbelt Area Alaska, Upper Susitna River Basin, Interim Feasibility
Report," Appendix I, Part I, p. A-19. The equation was derived from the
A-10
four stations, Maclaren near Paxson, Susitna near Denali, Susitna near
Cantwell. and the Susitna at Gold Creek. The relationship derived shows
that a direct estimate of yearly sediment, measured in tons, can be
obtained by the simple relati'onship of:
s = 89,144 X H X Ab
Where
-0.129
S = Sediment in tons per year
1. 129
H = Average Basin height in miles
Ab = Basin area (square miles)
Ag = Glacial area within the basin (square miles)
V1 =Volume of sediment for the life of the project (acre-feet)
The second analysis was taken from Gary L. Guymon, 11 Regional Sediment
Yield Analysis of Alaska Streams," Journal of the Hydraulics Division,
Volume 100, HY 1, January 1974. This analysis uses a variety of streams
throughout Alaska. including all of the above mentioned stations with
the exception of the Susitna near Cantwell. The article derived a gen-
eralized equation with a length parameter instead of a height parameter
as indicated by the first analysis. The following is the equation as
derived by Mr. Guymon:
Qs = 33,000 Ag
Where
0.563 -0.702 -0.135
Qs = Mean annual sediment yield per square mile of basin area
At = Total drainage area (square miles)
Ag = The glacial drainage area (square miles)
L = Length of stream below glacier (miles) V~ = Volume of sediment for life of project (acre-feet)
Assuming that the project have a 100-year life the average reduction
in storage volume would be equivalent to having the reservoir volume
reduced over its 100-year life by the volume of sediment which would
be deposited over a 50-year time interval. It was also assumed that
20 percent of the sediment would be distributed in the upper elevations
of the power pool while 80 percent would be distributed in the dead
storage such that the intake works would be above the sediment.
Based on the previous assumptions the volume of sediment for the
two analysis for Solomon Gulch are V1 = 2,000 acre-feet and V2 = 4,000
acre-feet. Similarily the volume of sediment for the two analysis for
Allison Lake taking into account the assumptions are V1 = 780 acre-feet
A-ll
and v2 = 1 ,670 acre-feet. Since both analysis were an approximation of
a phenomenon for which there is no data, it was decided to be conserva-
tive and use the 4,000 acre-feet value for Solomon and 1,670 acre-feet
for Allison. The reduction in storage was applied only to Solomon
Gulch, since it is shallow and would lose storage. The storage for
Allison Lake was not reduced since it is very deep and the loss of
active storage would be mtnimal.
EVAPORATION
The normal high relative humidity, high percentage of overcast days,
and cool climate preclude any appreciable loss from evaporation. Estimates
of flow were based on records of existing or historical gaging stations
near the project areas, and include evaporation from the stream surface.
Due to the northern latitude and prevailing maritime climate additional
evaporation from the reservoir surface would be insignificant.
A-12
STREAMFLOW CHARACTERISTICS
LOW FLOW ANALYSIS
Power studies utilizing the 28 years of rec6nstituted data for
Solomon Gulch indicate that 1951 was the critical water year. The USGS
records are available for this critical period which extends from
September 1950 to May 1951, a period of 9 months.
FLOOD CHARACTERISTICS
Snowmelt type floods are dependent upon two conditions: {1) the
amount of accumulated snow; and (2) the temperature sequence during the
spring melt period. A large snowpack over the basin will give a large
volume of runoff during the spring, however, if the temperatures increase
gradually, causing slower snowmelt, the flood peak will be just slightly
above normal. If the early spring is colder than normal and then the
temperatures rise rapidly for a prolonged period, the flood peak will
be extremely high with the duration of flooding dependent upon the total
snowpack.
Rainfloods produce the highest flows, and these occur in the fall,
generally between late August and October. The flood peaks are quite
sharp due to the fast runoff, which is caused by the steepness of the
terrain and the low infiltration losses into the underlying rock.
PAST FLOODS
The maximum instantaneous recorded discharge for the three recording
stations utilized in the study are:
Lowe River
Power Creek
Solomon Gulch
FLOOD FREQUENCIES
Date
9/11/75
9/25/49
9/04/51
Peak (cfs)
12,600
5,540
2,420
Graphs A-1 through A-3 show the peak flow frequency for the three
gages utilized in the study. The following is a tabulation of the peak
discharges for the various recurrence intervals:
A-13
Peak Discharges -cfs
Recurrence Lowe Power Solomon
Interval River Creek Gulch
(years)
5 11,900 3,750 2,200
10 14,900 4,650 2,600
25 18,800 5,750 3,200
50 23,000 6,900 3,750
100 27,500 8,000 4,300
PROBABLE MAXIMUM FLOOD
This section describes the derivation of the Probable Maximum Flood
(PMF) for the two sites, Allison and Solomon Gulch. Design floods were
used for spillway sizing and estimates of downstream inpact. Flood
hydrographs were computed by applying the Probable Maximum Precipitation
(PMP), as derived by the National 11eather Service (NWS} into the Soil
Conservation Service (SCS) method for computing an inflow hydrograph.
Once on inflow hydrograph was established this inflow was routed through
the reservoir to assure the adequacy of the spillway.
The PMP for the 6, 12, and 24 hour precipitations are 14.0 inches,
20.7 inches, and 27.5 inches respectively. These precipitation were
utilized along with the SCS method as outlined in the "Design of Small
Dams," Bureau of Reclamation to derive the inflow hydrograph for the
two above mentioned basins. The PMF was utilized to size the spillway
at Solomon Gulch, but was not used for the Allison site since there is
a natural outlet.
A-14
):>
I __.
U"l
-1
Ql
0" __.
I'D
):>
I __.
LOWE RIVER STREAMFLOW -CFS
---------------------------··· ---------------------------------
YF~P __ nrT • Nnv f)F~------'-~IH' H=•1 ri./IIJ fiPI> 1-'I.Y ______ :I_I_!'i ··--·.:.'_!.!1 ..... ·-·· A}!!!.. .... ';fl' /1\IFf.'_llf;r -----------·-------------------~---"----~-----·---·------------ -----------------------------------
I'll?.
----, 'l7 1.
1 Q 7'·.
1<ns.
,, ( '~ .
. r;pt;, •
?? l.
ld-.,f...
I/
" .
t n 1 • 7l •
7/4. l( l.
'"' ,, . -~" .~.--'~ 7.
(,( • :·Ill (1. J /(, ., • ( "; (, ";. '., ;. .. , • l 4 -~ 7 •
4'' • 1 •; • •,/ • ------,,,., l • 1 'I :10. ·.j)(:(·: ----.. 7'? :J;;---QH 'I •
~. I • l,l{.
S1., 4q• ~~. 4'i. f-.74. ?197. 41~7. ~771. ~3~7. l??H.
A7; ·-,,.(·:------4'1. 4(:j• 7ff. 7">"14. 'i]'l4o ?".f-.'1 0 7':iH1 0 )?1'>.
~--· ·--------·-·-
~--.~-----------------------------------------------------
SOLOMON GULCH STREAMFLOW -CFS
YEAR OI.T NOV OF'C JAN FEB MAR APR MAY JllN JUl AUG SEP AVERAGE
----~---------;.-~--------~·-·-······ ----~-------------------~----·~~----·
IIIJ5l. Jll. "14.
lQ5?.. 75. 74. 21. 14. 11. 10. 9. 45. 366. 7<;3. 29?.. 219,. 157 ..
1.-.-,~. ...}", . ..,.. l.JJ.. ,;:)\·· .l.O• 1.£• .LJ.• lR. ll'+. 544. 40t<C. 34~~-Zfi4. 1':1~.
1954. 143. 35. 17. 11. 12. A. 11. 164. 357. 277. 356. 245. 136.
l'f5~. 1""• tCf. IZ. tz. tt. LO. h. 31. 320e 5lq-;-.'Shl• --T7.h. T3~.
148. l 956. 5~>. 27. 17. 21. 12. A. 14. 90. 371. 507. 442. 212.
------·-------------------
-----·---------·-· -------·--------------·---..
----------------------·-------------·-------------------------------·
---~----~---~ -~ --------------~--·
---------------· ---------------------------------
J
7'
---·------------------
);:.
I ........
m
-1
OJ
(t)
);:.
I
N
'I' fAR ~IJCT~-----NOII OEC ·---------·-----------------1q48, ;!8;:1.-3"7. 10~.
1949, 36'5. 199, 60,
--! <;l '\() .. ------48.7-.---31 8 73.
19'51. 123. ''i3. 37,
1952 •. 250, ___ 232. so.
19"i3, '59'-1, 21->7, 85,
19511 .. 3113. 102, 59,
19'55, 387, 290, 53.
--195b. 1Sl.-60~----311.
! 9'5 7. !3ll, 246, 100,
!9'58. uoo,_ ---334, 69,
19'59, 3811, 1 1 2. 1:\3.
!960. 328·------I hS. 7A.
1 96 I. 21'l. 1 0 1 • to a.
1'i62 .?.91-..--1 1 Or---~--61 0 , %3, ?all, 1119 • 121\,
1964. 255. h5, Ill 0.
1'165. ?58, 196, ! 1 1 •
-~ !96b, --326,... ___ AO, 5ll.
!967. 360. 177. liA. -1968, ___ !7~ 2'>9..---102,
19"9· 184, ! 09. 59,
!970. 1141----203. 190.
l 9 71 • 259, 162, 711,
!972 •. 2tl1. fl1 • 39,
1973. 3'10, 90, b' • 1974, --· -.155, ____ %. Ill\,
1975, II no. 2'5£1, 8ll. o. 3 0 u.. ---173. ao.
---~--------~---
JAN --·-·--
FH,
llY,
'lb,
25.
35,
5\J,
50 ...
60.
3~.
L! q.
1 n.
ll 3.
11'-1,
1::><4,
8 l •
'l2.
h3.
43.
B.
3h,
"i£>.
?7,
10 0.
c;b.
?':>,
34.
3b,
"ih,
'S I •
POWER CREEK STREAMFLOW -CFS
FER ~1A R APR MAY JUN .JUL.---AUG .. __ S.EJ~----· A.li£RA1iL_ -------____ ..., __ -------------------------·----·-··-----------··--
'511, ;:> 8 • 24. 218. 561'>, 667. ll53. .478. ___ _2l_tt_...
',(), 113, 3 '5 • 1112. ~7~. 11'511, 113'5. 749. ?Ill>,
i'?. ?.':>, 2'5. llJ 1 • 571. 1100. 112ll ____ ____b.3.2..__ 2c3,
,>O. ~3. 3ll, Po. ~55. 539, 397, 10?4, ?3 t.
2". ? 0. ;>O. 911, '-127. 8CJ7 • '-185. .. 31'l8 ·--____ ..2 q ~~___
3' • ~?. so. 2c;9, c;qc:;, 511;:>, f>20. ll"i1, ?98,
4 7. ?B. 30. 1 '19. ll12. 451. 61?. ~-_46 L~ ...... __ 23.2...,_
lj' • ?'1. 21l. 102. 37 2. b71. 6u3. 294, 244.
2'. I b. 2?. . ---17 7. . ~56. _b12 H6.~ __ 4.25 • 2l<l.
;n ::>3, 2ll. til 0. ll2?. llS7. 484. 973. ?60,
41-,, II S, 65. 297. S'lA, 925. 673. 256 L. --~~U3...__
·~ li • ;:>4. 57, 2~6. 1164. S'l2. 331. 2b5. ?17.
:,o. 'Ill. 3'1. ?71. IH)"i., 6?8. 536. 4 71. ______ 26.3~
1-, ••• 42. "i9. 308, 420, SOb, '51!7, 4116. ?57.
u t.:.. 42. 43. 17 3. "199 1.17.2-___ 3_55 3b.i. 201!. . , 5". qll. 1 0 ll. ?,llQ, 3R;>, ')93, 43?. 326. ?49,
6a, II 7 • 44. 100. 1196. 610. ll'lO,. --····· 291. _ ____22.2..,_
3q. 1!7, 96, 1117, ll211, ll33. 436. 5'16, ?36.
"'· ?2. 3<1, 1116, 3/:ll. U30, 56 5. --__ 713 ... 23!l..-
t~ (.l • '\9. 8Q, 1 R 0, 451l, t!ll6, 11911, 736. ?611.
1 B. 1 3 4. 53. --273, .1101. 52, 336._-3!0 222.
~ h • <l3, 'lll, ??1\, liSA, 3Q8, 25?. ? 1 7. 1 8 0.
14?. 11 4. 1 l) 3. 172. IJ27, 526. 6t!O, ____ . _J66. _____ 2_8b_._
4~. ?7, 47. 1 1 6. llbf,, 681. "i5<J, 3 Pl. ? 31l.
1 0 • 1 6. 1 h. 101, 32A. Sft5, sus. _5112 ______ 2-lQ..__
~ (1 • ::> 1 • 37. 1119, ~51 • 11119. ll7A, 234. 193,
(J n .. 1 y. ull. 1116. 3Slj. ---352 340·---~dl. 17.9_
l1 '( • ?h, 40, t7'1. 3tl?, n~?. ~~~~~-6011. ?h?.
'> 1 • I! 2, tP1, 1R6, 43?, SSt. 11/H • qat. 2lll-
---~·------~-----------------
Month
January
February
March
April
May
June
July
August
September
October
November
December
TABLE A-3
SOLOMON GULCH NEAR VALDEZ
Correlation Equation Correl!~ion Coefficient
R
0.414
0.414
0.414
0.738
0.950
0.759
0.950
0.979
0.960
0.810
0.830
0.810
LOWE RIVER IN KEYSTONE CANYON NEAR VALDEZ
January
February
March
April
May
June
July
August
September
October
November
December
QL = 0.420Qp+ 44.95
QL = 0.420Qp+ 37.55
QL = 0.420Qp+ 34.06
QL =-0.682Qp+ 77.08
QL = 2.748Qp+ 107.20
QL =14.85 Qp-3182.44
QL 7.068Qp+ 1169.28
QL = 7.076Qp+ 406.69
Ql = 6.9000p-830.42
OL = 0.898QP+ 140.17
QL = 0.862Qp+ 40.86
QL = 0.700Qp+ 42.44
Op = Power Creek monthly streamflow
Os = Solomon Gulch monthly streamflow
QL = Lowe River in Keystone Canyon monthly streamflow
A-17
0.468
0.468
0.468
-0.998
0. 716
0.894
0.664
0.905
0.747
0.862
0.966
SOLOMON GULCH
------~ ---· EXTENDED STREAMFLOWS
-CFS-
YE,\R OCT WlV nu Hr~ 'E"l MAll APR MAY JUf\1 JilL AU(.; SF,P AVERAGE ·----·-------· _.., _____ --·------------------___ .. ___ ·--.. ---___ ..., ___ ------· -------·--------------...........
1 91J8 •.. az...--103. 4 1 • ?. I • 1 (I. 'l. Q, 1 7 4. ll51. 5?1. ?7ll, i!ll4, ···-164,
1949, 154. li7. 2?. 1 (I • 1 (l. 1 c. 1?. Afl, 1i ?.7 • 301>. ?611, 396, 139,
19"iO. 87, Fill, 3h. 1 h. 1?. '1. 7. 09, "'ibA, 277, ?5ll, 2"i5. i2'i.
1951.--. liP. •.... ?2. I 0 , 1 • 4. 7 • 11\ • "ill, ?&1. 31!6. ?5Ll, 571!, 13"'i.
1952. 75. 74. 21 • 1 4 • 1 1 • 1 (). 9, ll'), 3bh, 7'13. ?4?. 21 9. 1 '57.
1953, 30/J, 11i 1 • 30. 1 H, 1 ;> • I 1 , 1 A. 2?1l, c; Qll. t!OI\, 1i4h. ?h4, 19?.
19"ill, 143 •. 35. 1 7 • l l • P. 1\ • I 1 • 1 114. 3':>7. 277. 'i')h, 245. ·-··· 1 36 •..
19'i5, 1 3 A. 74, 1?. 1 2. I 1 • 1 () • A • 37. 1i20. 51 4. 1i 6, • 1 ?h. !3"i.
! 9%. 56. ?7. 17. ;> 1 • l?. Fl. I 4. 90. 3 7 ! • "107, ll4?. .'12. I 4 A,
1957. -52~. 110. 39. lll. Q, 8. 9, 1 :" l • 357. 309, ?9?. 5?2. IS?.
19'i8. 1 b I. 10 4. ?h, ?5, l 1i • 1 2. 21 • 211:5. 117?. 7111. "'i9P, PO. ?00,
J:> 1959. !51>. 42. 9. 13. 1 1 • i:l. 13. 1 <Hi , 3 81~. 41l5. ?Oh, t?'i. 131i.
I 1960. 131. 57, 30. 20, 1 'i. 1 (l. 13. 2'13, 385. Q81. 'i? 1 • 2 tl I • 1 b 1 •
--' co 19€-1. Bb. 1i9, b 7 • ?7. 1 h. ' 1 • 1 0. 275, 3?11, 3"iH, "'i49. ;>II 'I, 154.
19h2. I 16. 4 j. 2"1. ?u. J"'i. 1 l • 1 "i. l?'l. 'it;;:>. 3?tl. ;>?(l. 1110. I 1 q.
1%3. 98. I,Q, s 1 • ;> 1 • 30. ?0. ~?. 1"'1'1. '! 31 • Qllo. ?b">:. 1'1'1. 143.
1'lb4. I 01. ?9. "'7 . I 7 • 1 h • 1 2. l <;. It() 0 I!Q"i, llh3. ;>q<;, Jll 0. 13?.
196':>. 10?. no. 4/l • I 4. 1?. 1 2. 30. t-.:9. 361 • ;?At;, ?6'i. 21\8, I 3"i.
1%6. 130. 'B. 1 a • 1 2. CJ • /j, I lt • "'2. 3 31 • 2A 1 • "1:37. .576. 137.'
196 7. 1411. h 1 • 17. I 2. 11i. 1 4. 21'1. l 1i 1 • -, 7 p, • 33K, ?97, 31''-. 1'5?.
!9htl, bA, 113. lHl, 1 b. 3"i, •6. 11\ • ?36, 1i44, 304. ?oa. l <; 0. 1 27.
1 96 9 ~···--· --. .7 2 • Ill. 2?. 11. 11 • ?0. 29. lAS. 381. 2119. 16?. 'HI, 107.--
1970, lllO. h8, HI, ?3. 21'1. ?,5_ 3?. 1?2. 360, 378. 37(), til?.. 1'Sil.
PHI. 103, lib. 2R, 1 6. 11i • "'· 16. 'i8. 3tsh, 51i5. 334. 1 c; 5. 111?.
1972. 114. 3il, I 3. 11. A, 7 • 7. ll 1 • 296. 41 8. 30l1. 2"0. 121'1.
1973, 136, 36, 2?. I 3. 1 0 • R, 1 3. 1111. 31 1 • 30 l • i?fiP., 10~. 1 1 h.
I 97 4 • 60, ?7. 17. 12. 1 n. 8, t h. 137. ~1'. 203. ? 11 • 2 71l, 107.
1975. --11:! '5. A2. 3?. 1 b. !?. 9. 1ll. 1?9. 331. l185, ?38. 315. . ... 1')4, __
0. 11 p,. 5Ci, :~ 1 • 1 b. 1 4 • 1 I • 1 6. 1"'i 7 • 3611, 403. ?•n. 24b, Ill?,
-t
Ill a-
--'
I'll
;:r::.
I
~
l:>
I ......
\.0
-l
PJ
0"' ......
(!)
l:>
I
(J1
ALLISON CREEK ESTIMATED
STREAl1FLO:.IS
-CFS-
_'f_~~ ___ Q_c;T -~~~ __ __Q_E_C ____ ,JAN FE_~---·''A~ _____ li?_B "A! _____ JU!~------JlJL ____ AUJ; ______ SEP ------~-VERAGE _
__ t'l1J.8. ____ 3a_.___ __ 3s. _____ l£J. .. _______ l.. _____ s • ______ 3. ______ .3L ______ 59. ______ I '52. _____ l7o. ________ 93. ____ 83. ____ .So._
19~9. 52. 23. 7. 5. 3. ~. ~. 30. Ill, 103. 89. 134, 47,
__ _._t~Q_')() 2..'!__. ?P.. 12.. ~ 2_._ __ ____3_il~___l2..4~---·-9.lJ. _ ___86, ____ 86 42._
1951. 16. 7. 3, o. 1, 2. 3. 18. 88, 117. 86, !9lJ, 45.
___ l'!S.?,_ ____ l'i. 5... a 3.__ 3. _____ !5. _____ 12tJ. ___ 255. _______ 9_9. ______ 7l.l, ____ 53. __
1953. ,103. ~~. 6. ~. lJ, 6, 76. l8iJ, !38. 1!7. 89. 65,
_ _j QS(J, ____ IJ8_. ______ J 2 , _____ h.., IJ_. a. 3. ~.___ __ 55 • ____ 121. ____ 9a. ____ 120 • ______ 83. ____ '!6. __
19'55. !J7, 25. Q, IJ, 4, 3. 3. 12. 108, l7iJ, 122. '13. '16,
1 9 56. 1 9. 9. to. 1 • 4. 3. s. 3.l. 1.2.5....__ 17 t. "L't... z 2.. s_o_..__
1957. 17. 27. 13. 5, 3. 3. 3. '1~. 121. !OIJ, 99, 176. 51.
___ L9")_B.__ _ SiJ 35 • ___ __<!_. e. 4 _(J_, ____ IL__ __ a~L--_15.9_. ___ 261J._ ____ _13'~ ·----q 1. _____ 67. __
1959, 53. 1iJ, 11. 5. l.l, 3. IJ, 66, 130, ISO. 70. 42, l.l6,
t'lov_, _______ u~._ __lc; • _____ J o_. 7 5.-3_. ~ 9_. ___ UQ. ___ _163 • ___ ! oe. _____ t\1 .. ____ 55. __
196\. 29, 13. 23, 9, 5, 4, 6, 93, 12[1, 121, 1\R, SiJ, 52,
__ J.'!2~_._ ____ 3_9_, 1 c:.. " _. a lJ iJ 1. 11 t-1 o_9. 7li l:lL .. ___ Ao._
1963, 33. 22. 17. 7, 10. 7. 11, t7. 112. 1'51. 89, 5iJ, 48,
1%tJ ·--__ ] ·J_._ 10 • _____ [_<! ·---____ !,. '---------/:> ·--------". ---___ 5. ----___ 1 3. ___ 13 7 ··---__ 15 7,-10 0 •----_lJ 7. ---4 5.--
1'-ic'). 35. 22. 15. 5. IJ, lJ, 10, iJ], 122. 96, 90, 97. 46,
1966. _____ -'lll, ___ ·---11, _________ ]. _____ 4_. ______ 3. ____ 7,_, ______ _5_._ _____ 31. _____ _1 12, _______ 95_, 11Ll. 127. '16,
1967, iJ9, -20. 6, 4, Q, 5. 9, ua, 1213, 11/J, 101. 131. 51,
___ t9~~. ___ 2_3_. ____ 2i'-\4, ____ _?_, Jj_, o 6_. ____ P,_O_, ____ Uh_, ___ l03, _____ _7_1, ___ 51 • ______ 43, __
1'169. 2/J. \!;, 7. !J, IJ, 7. 10. 62. 129. 8~. ss. 35, 36.
1nn. &1. n.. 2~:>. e. 10. e. 11. u1, 122. 12>3. 128. o!. 52. ---I ;fl. 35.-------1 G.----·----9.------5.------ll, ·----·-----3.-------5 .---'ic:. -----(30. I i' 1. 11 3. '52. 48.
1 .. 72. 30, 11. ~. ~. 3. 2. 2. )1:,
---~;:, 7:~. -------4-6. --------1<' :----·e .----4. ------·---3-.---------3 .·------;_; :· ----------,, .•
__ J ~r~. _______ 2·'... ________ '!_. ______ ~::~. .'!..·-------·~-·--------_3_. _________ s_. _______ 1..6.
I '1 7 5 , i: 3 • 2 F-• I I • '::> • t.: • 3 • 5 • '" ·J •
,.r.. 20. 10. s._ s._ i.i, '::._ ~"·
1 u ·'.
lf'':J,
1 (il-,.
1 12.
12.5.
--------·------·--------------------------------------
1 :j 3.
9B.
__ }!.
[. ij.
'19,
Q'-). !.13,
3o, 3 '1.
----·-· ·-· l:J3. ---____ 31::.
l 0 i). 52,
a:s. '18,
:::t>
I
N
0
.G") -s
Q>
-o :::r
:::t>
I
10000
9000
8000
7000 maximum discharges for period ol record
6000
are plotted as described in "SLatlstical
in Hydrology," by Leo R. Heard.
5000
4000
3000 ! 3.
curve vas computed by correlation with
other stream gaging records utilizing HEC Re;:;ional
Frequency Program 723-X6-L2350. Period of Rucord
extended to 28 years thus yielding an equivalent
length of 19.9 years.
Zero skew coefficient was used.
2000
VI r.. u
:z: ....
~
~ 1000
... 900
BOO
700
600
500
400
300
200
Slli.U~l\Hi t:IILCII ll!'nt' VAI.LWZ
Stn•.1m !:aging St.1tion 15-2260-00
D.A. 19 Sq. Hi.
t\Nt-.1JAL PEM; DISCHARGE FREQUENCIES
Alaska Distr ct, Corps of Engineers
TOR Nov 75 II !Tiii!llli Tllifi![i,Ji[! i iiilti:til:il, · 1: iTLJdili'lll·'ll·irl I,
100 001 0,(1! Q.l 0.2 O.S I ? S 10 >O 'lll •n •o M 70 •o 90 95 98 9t iU 9U tl.tl
100,000
90,000
80,000
70,000
60,000
50,000
40,000
30,000
20,000
t!! u
:2: ....
::J::o ~ I
N ..... ~ 10,000
9,000
.. 8,000
7,000
6,000
5,000
4,000
3,000
en
'"'S 2,000 Ql
"'0 :::r
::J::o
I
N
1,000
1.
2.
I 3.
99 9t 95 90
Annunl mttximnrn dischnrr,cf< for period of record
1971-1974 arc plated ns described in "Statisticnl
McthodR in Hydroiogy," hy Leo R. Beard.
Frequency curve wm1 t~ontputcd by corrclntion with
other stream gnging records utilizing HEC Regional
Frequency Progrnm 723-X6-L2350. Period of Rt>cord
ext('nded to 28 y('nrs thus yielding an equivnlcnt
length of 11.9 years.
Zero skew coefficient was used.
LOWE RIVER ncar VALDEZ
Stream GngJng Station J~-2265-00
D, A, = 2 0 I Sq • M l •
ANNUAL PEAK DISCHARGE FREQUENCIES
Alaska District, Corps of Engineers
TOR Nov 75
90 95 98 99 1111.8 99.9 "·"
);>
I
N
N
G"l
""'S
01
"'0 ;::,-
);>
I w
.....
1000 9U9 90
"' 500
"" u
z .....
6
~
::!
lol .....
so 40 30 zo 10 0.~ 0.2 0.1 0.05 O.Ql --,10
NOTES:
l.
2.
3.
Annual maximum discharges for period of record
1947-1974 are plotted as dt•scribed in "Statistical
'!C'thods in Hydrolo;w," by l.co R. BC'ard.
Frequency C'urve was comput t•d utilizing l!EC Regional
Frequency Program 723-Xh-1.2150.
Zero skew cor•fficlcnt was tlsed.
POWER CREEK near CORDOVA
USGS Stream G"ging Station 15-1260-00
D.A. • 20.5 Sq. ~i.
ANNUAL PEAK D1SCHARGF: FREQUENCIES
Alaska District, Corps of Engineers
TOR Nov 75
90 9S 'JB 99 99.8 99.9 9HI
20,000
10,000
9,000
8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
SECTION B
PROJECT DESCRIPTION
AND
COST ESTIMATES
SECTION B
PROJECT DESCRIPTION AND COST ESTIMATES
TABLE Of CONTENTS
Item
PERTINENT DATA SOLOMON GULCH
PERTINENT DATA ALLISON CREEK
GENERAL
SOLOMON GULCH
Dam
Diversion Plan
Waterways
Powerplant
Switchyard and Transmission System
Reservoir Clearing
Access Road
LAKE TAP AT ALLISON LAKE
General
Valve Chamber
Power Tunnel
Surge Tank
Penstock
Access Adit
Intake Trashrack
Powerplant
Switchyard and Transmission System
Access
COST ESTIMATES
Basis of Estimates
Page
B-1
B-3
B-5
B-6
B-6
B-6
B-6
B-7
B-7
B-7
B-7
B-8
B-8
B-8
B-8
B-9
B-9
B-9
B-9
B-9
B-9
B-10
B-11
B-11
Reservoir
PERTINENT DATA
SOLOMON GULCH
Maximum Elevationt feet msl
Average Elevation, feet msl
Minimum Elevationt feet msl
Tailwater Elevation, feet msl
Surface Area at maximum elevation of reservoir, acres
Usable Storage, acre-feet
Hydrology
Drainage Area, square miles
Annual runoff in acre-feet
Average, cfs
Maximum, cfs
Minimum, cfs
Dam -concrete gravity
Height, feet
Top Elevation, feet msl
Spillway Crest Elevation, feet msl
Spillway Design Flood, cfs
690
642
631
10
710
25,650
19.5
143
200
107
115
695
665
31,000
Penstock
Type
Diameter, feet
Length, feet
Shell thickness
Steel -ASTM A537 Grade "A"
4
3,645
Maximum, inches
Minimum, inches
Support Spacing, feet
Type
Powerplant
Number of units
Type of turbine
Installed Capacity, kW
Plant factor, percent
Net Head
Maximum, feet
Average, feet
Minimum, feet
B-1
1
1/2
30
Concrete
2
Francis
6,200
50
663
644
612
PERTINENT DATA
SOLOMON GULCH (cont)
Generator Rating, kvJ
Power Factor, percent
Voltage, kV
Powerhouse
Transmission Line
Voltage, kV
Type
Length, miles
System Characteristics
Transmission Losses, percent
Dependable Capacity, kW
Primary Energy, MWH
Average Annual Energy, M~JH
B-2
3 '1 00
90
13.8
steel structure on
concrete foundation
115
single circuit wood pole
9.0
2
6,200
28,502
40,780
Reservoir
PERTINENT DATA
ALLISON CREEK
Maximum Elevation, feet msl
Average Elevation, feet msl
Minimum Elevation, feet msl
Tailwater Elevation, feet msl
Surface Area at elevation 1,367 feet, acres
Usable Storage, acre-feet
Hydrology
Drainage Area, square miles
Annual runoff in acre-feet
Average, cfs
Maximum, cfs
Minimum, cfs
Lake Tap
Top of Lake Tap Entrance
Spillway
Tunnel
Size, feet
Length, feet
1,367
1,335
1,267
15
258
20,678
5.7
48
255
0
1 ,250
Natura 1 out fa 11
10-foot horseshoe
8,100
Penstock
Type
Diameter, feet
Length, feet
She 11 thickness
Steel -ASTM A537 Grade 'W'
3
12,850
~1aximum, inches
~1inimum, inches
Support Spacing
Type
Powerplant
Number of units
Type of turbine
Installed Capacity, kW
Plant factor, percent
Net Head
Maximum, feet
Average, feet
Minimum, feet
B-3
1-1/4
1/2
40
Concrete
2
Impulse
7,560
50
1 ,324
1,285
1 ,231
PERTINENT DATA
ALLISON CREEK (cant)
Generator Rating, kW
Power Factor~ percent
Voltage, kV
Powerhouse
Transmission Line
Voltage, kV
Type
Length, miles
System Characteristics
Transmission Losses, percent
Dependable Capacity, kW
Primary Energy, MWH
Average Annual Energy, MWH
B-4
3,780
90
13.8
steel structure on
concrete foundation
115
single circuit wood pole
1 o. 5
2
3,780
33,116
35,749
GENERAL
The five alternatives, Mineral Creek, Unnamed Creek, Lowe River,
Solomon Gulch, and Allison Creek were previously mentioned as alterna-
tives for hydropower in the Valdez area. Of these five, only Solomon
Gulch and Allison Creek appeared to be feasible and will be discussed
here. Both of these projects would be located on the south side of
the Port of Valdez with the only road being the pipeline road to
Alyeska's tank farm which passes close to both sites.
B-5
SOLOMON GULCH
DAM
Previous study by Robert Retherford Associates identified a earth-
fill dam with a spillway and minor dikes on the east side of Solomon
Gulch. Further evaluation of an earthfilled dam will be completed in
the feasibility analysis, but at this time it was felt that a concrete
gravity dam with a gated spillway would create less environmental
impacts and return any spilled water directly to the main channel, as
shown on Plate 1. It should be noted that this mapping was made avail-
able through the Copper Valley Electric Association (CVEA) report on
Solomon Gulch completed by Robert Retherford Associates.
The concrete gravity dam would be about 115 feet high with the top
at the 695 elevation. The spillway crest is at 665 foot elevation with
two 30 foot by 30 foot tainter gates. The spillway would have a capacity
of 31,000 cubic feet per second (cfs) with a maximum flood water eleva-
tion of 690 feet. (See Plate 2.)
For purposes of this report spillway energy dissipation will be
handled by a flip bucket located at the downstream dam face. Future
studies will more fully evaluate the suitability of downstream bedrock
for this type structure and the downstream channel capacity to prevent
backwater on the flip bucket during design flows.
Releases for fish pruposes require about 4 cfs. A 12 inch steel
pipe will be embedded in the dam and provided with two valves near the
intake for this purpose.
DIVERSION PLAN
A 10-year frequency flood of 2,600 cfs was used to size the diversion
facility. The existing abandoned concrete dam (Plate 2) would be
modified as the diversion intake with provisions for stoplogs. Two
9-foot diameter concrete culverts approximately 255 feet long would be
laid near the existing streambed and would convey streamflows downstream
of the dam. Dam concrete would encase the culvert during construction.
On dam completion the diversion stoplogs would be inserted and the encased
culvert section through the dam plugged with concrete. Consideration
will be given to plug removal through blasting for emergency drawdown
capability as required in ER 1110-2-50.
WATERWAYS
The power intake structure will be incorporated into the concrete
gravity dam. It will contain an intake chamber and a steel trashrack.
B-6
Upstream closure would be controlled by a vertical lift, slide wheel
gate (4 feet by 4 feet) and hoist. A bulkhead gate would be located
upstream from the regulating gate.
The penstock will be 4 feet in diameter and approximately 3,700
feet long. It would follow the ground surface from the dam to the
powerhouse with the exception of crossing the Trans-Alaska Pipeline
which will be done by a bridge. The surface portion of the penstock
would be supported by concrete piers with ring stiffness.
POWERPLANT
The Solomon Gulch powerplant would be located adjacent to the
Solomon Gulch outlet into the Port of Valdez. The powerhouse would
contain two vertical Francis turbines and two 3,100 kW, 3-phase syn-
chronous generators. The powerhouse structure would contain the gen-
erators, turbines, a 20-ton bridge crane, and all other equipment
required for operation and maintenance. The access road to the pipe-
line terminal passes directly in front of the powerhouse. Additional
study will be made to determine the need for a surge tank.
SHITCHYARD AND TRANSMISSION SYSTEr~
The Solomon Gulch switchyard would be located adjacent to the north-
eastern side of the powerplant. The transmission system would be approx-
imately 9 miles long. It would consist of single wood poles with the
exception of where it would cross the Lowe River and the marsh area near
Valdez which would utilize steel towers. Power would be transmitted to
the Copper Valley Electric Association's (CVEA) bus which would distrib-
ute it to the city of Valdez. For purposes of this report a 115 kV
transmission voltage is assumed since CVEA is planning a transmission
line to Glennallen at that voltage.
RESERVOIR CLEARING
The reservoir clearing operation would remove all timber and brush to
an elevation 5 feet above the maximum floodwater elevation. r.1erchant-
able timber would be sold, and brush would be stacked and burned.
ACCESS ROAD
Permanent access to the dam for maintenance of the intake and outlet
gates would require an access road from the existing oil pipeline right-
of-way up to the upper reservoir which would be about 3,700 feet long.
Paving of the road is not considered necessary.
B-7
LAKE TAP AT ALLISON LAKE
GENERAL
The 1ake tap wi11 be made at approximately the 1,250 foot elevation
which would provide a draw down of approximately 100 feet with the
initial water surface elevation at 1,367 foot elevation. Tapping would
be accomplished by driving a tunnel toward the lake from a suitable
elevation downstream from the lake outlet. When a short reach, about
9 feet of rock separates the tunnel from the lake, a rock trap would
be excavated a short distance downstream. After careful geological
investigation to assure no adverse geologic conditions exist, the final
round would be drilled and blasted. The rock trap would provide space
to catch and permanently store the rock from the final plug blast.
The selected scheme includes a lake tap, rock trap, and a power tunnel
leading to a valve chamber which seals the power tunnel off with a
concrete plug. It will then continue as a penstock in a 10 foot wide
by 10 foot high horseshoe tunnel to the surge tank and then continue
in the penstock tunnel until it daylights at the 1,250-foot elevation.
It will then continue down to the powerhouse. Also there will be a
diversion by means of a 6 inch pipe back to the streambed to provide
4 cfs flow for Alyeska's water supply and water for fish. All gates
would be closed when the final plug is blasted. The power tunnel branches
off from the side of the lake trap above the floor level, so the rock
from the blast would not be diverted into the power tunnel itself.
VALVE CHAMBER
The valve chamber is an enlarged portion of the penstock tunnel
which follows the power tunnel and a concrete plug as illustrated in
Plate 4 The valve chamber will have two 36 inch spherical valves, one
manual and one remote control. Access to the valve chamber would be
via the penstock tunnel.
POWER TUNNEL
The partially lines power tunnel exposed to lake pressure will be
approximately 300 feet long with the invert at the 1,240 foot elevation.
The sediment trap would be located immediately upstream from the valve
chamber. This would be an enlargement of the downstream end of the
power tunnel with a floor elevation several feet below the penstock
invert and is designed to collect any loose rock fragments moving down
the tunnel from the lake tap explosions.
SURGE TANK
An underground surge tank would be connected into the penstock and
rise approximately 150 feet. The surge tank would provide a compartment
for water to allow rapid load pickup, rapid load rejection, and inherent
stability under load changes, which would occur during operation.
PENSTOCK
The penstock would be a 3 foot diameter steel pipe which would be
located from the valve chamber to the surge tank and then to the power-
house with an overall length of 12,850 feet. There would be a diversion
as shown on Plate 3 of a 6 inch pipe to provide 4 cfs for fish and
enough water for Alyeska 1 s water supply system. The 3 foot penstock
would bifurcate into two 2 foot diameter penstocks immediately upstream
of the powerhouse valve room wall. Each penstock would connect with a
spherical valve in the valve chamber at the powerhouse.
ACCESS ADIT
The access adit is shown on Plate 4 and is approximately 75 feet
long. The access adit would make it possible to build the valve chamber
and then blow out the lake tap without complications. A concrete plug
would seal the access adit during permanent operation.
INTAKE TRASHRACK
The power tunnel entrance would be covered by a steel trashrack to
prevent debris from entering the intake. The lake will have to be
drawn down through the penstock during the low inflow period for trash-
rack installation if underwater techniques cannot be used for installation.
POWERPLANT
The powerplant will be located adjacent to Allison Creek near the
tide water of the Port of Valdez as indicated on Plate 3. The power-
house would contain two synchronous generators with name plate ratings
for each unit of 3.8 MW. Each generator would be driven by a Pelton
wheel turbine. The powerhouse structure would house the generators,
turbines, a 15 ton bridge crane, and all other equipment required for
operation and maintenance of two units.
SWITCHYARD AND TRANSMISSION SYSTEM
The Allison Creek switchyard would be located adjacent to the power-
house on the east side. The transmission system would be approximately
10.5 miles long. It would consist of single wood poles with the excep-
tion of where it would cross the Lowe River and the marsh area near
B-9
Valdez, which would utilize steel towers. Power would be transmitted
to the Copper Valley ectric Association bus which would distribute
it to the city of Valdez.
ACCESS
The tunnel site is in very rugged terrain and it will be necessary
to implement helicopter transportation to gain access. The road to
the pipeline terminal would be adjacent to the powerhouse and be very
easy to connect with a short road.
8-10
COST ESTIMATES
BASIS OF ESTIMATES
All estimates are based on January 1978 price levels. The con-
tingency used for all alternatives was 20 percent. The cost data was
obtained from bid prices on recent major power projects in the Pacific
Northwest and Alaska, and adjusted to reflect current price levels,
Alaska labor costs, and transportation costs to the sites. The con-
struction time was estimated to take 2 years and power~on-line would
be 1985.
B-11
Account
No.
01
03
04
07
08
19
30
Feature
TABLE B-1
SU~1MARY COST ESTIMATE
JANUARY 1978 PRICE LEVEL
SOLOMON GULCH
685-FOOT ELEVATION
LANDS AND DAMAGES
Federal nds (4.150,000)*
Private Lands 1,785,000
Government Administrative Cost 174,700
RESERVOIR
DAM
Main Dam -Concrete Gravity 7,756,913
Minor Dams -East-West Center 726,100
Spillway 975,000
Intake Works 205,000
Penstock 3,940,825
Diversion Tunnel and
Construction Facilities 994,706
POWERPLANT
Turbines and Generators Powerhouse ]
Accessory Electrical Equipment 2,250,000
Auxiliary System & Equipment
Switchyard
Tailrace 41,030
Transmission System 1,092,000
ROADS
BUILDINGS, GROUNDS, AND UTILITIES
MOBILIZATION
Subtotal
20% Contingencies
TOTAL CONTRACT COST
ENGINEERING AND DESIGN 8%
Feature
Cost
$1,959,700
2,700,000
14,598,544
3,383,030
258,865
302,000
2,300,000
25,502,139
5,100,428
$30,602,567
2,448,205
*Values not included in cost. only the administration of Federal lands.
B-12
Account
No.
31
TABLE B-1 (cont)
Feature
SUPERVISION AND ADMINISTRATION 8%
Subtotal
Interest During Construction 6-5/8%
TOTAL COST
Average Annual Cost (Total x .06635)
Operation, Maintenance, and Replacement
TOTAL AVERAGE ANNUAL COST
,---------
B-13
Feature
Cost
$·2,448,205
35,498,977
2,351,807
$37,850,784
2,511,399
201 ,000
$ 2,712,399
Account
No.
01
03
04
07
19
30
31
Feature
TABLE B-2
SUt~MARY COST ESTIMATE
JANUARY 1978 PRICE LEVEL
ALLISON CREEK -LAKE TAP
LANDS AND DAMAGES
Federal Lands {5,545,000)*
Private Lands 2,109,000
Government Administrative Cost 225,300
RESERVOIR
DAM {NO DM·1)
Lake Tap, Power Tunnel, and
Penstock 13,053,040
Acces Adit and Surge Tank 885,704
Valve Control Chamber 227,643
Outlet Works 57,250
POWERPLANT
Powerhouse
Turbines and Generators
Accessory Electrical Equipment 2,560,000
Auxiliary System Equipment
Switchyard
Tail race 60,350
Transmission System 1,312,500
BUILDINGS, GROUNDS, AND UTILITIES
MOBILIZATION
Subtota·l
20% Contingencies
TOTAL CONTRACT COST
ENGINEERING AND DESIGN 8%
SUPERVISION AND ADMINISTRATION (8%)
Subtota'l
Feature
Cost
$ 2,334,000
0
14,223,637
3,932,850
350,000
2,000 ,000_
22,840,487
4,568,097
$27,408,584
2,192,686
2,192,686
$31,793,956
*Values not included in cost, only the administration of Federal lands.
B-14
Account
No.
TABLE B-2 (cant)
Feature
Interest During Construction 6-5/8%
TOTAL COST
Average Annual Cost (Total x .06635)
Operation, Maintenance, and Replacement
TOTAL AVERAGE ANNUAL COST
B-15
Feature
Cost
$ 2,106,350
$33,900,306
2,249,285
201,000
$ 2,450,285