HomeMy WebLinkAboutReconnaissance Study of Hydroelectric Power Alternatives 1979SEW �.._ CH2M
005 :CHILL
engineers
planners
economists
scientists
5 March 1979
K12404.A0
City of Seward
Box 337
Seward, Alaska 99664
Attn: Mr. Johnny Johnson
City Manager
Gentlemen:
PROPERTY OF:
Alaska Power Authority,
334 W. 5th Ave.
'Anchorage, Alaska 99501,
RE: Reconnaissance Study of
Hydroelectric Power Alternatives
Attached are twelve (12) copies of the final report on the
referenced study.
Of the four sites considered, the Grant Lake project is the
best source'of power from the standpoint of economic and
environmental impact. The Crescent Lake site was second;'it
was found to be less environmentally objectionable than in
the past, but the study also found the likely potential
power not as great as indicated in the FPC license appli-
cation.
It is recommended that the Grant Lake project be considered
further as a supplemental source of power for the city.
Crescent Lake might also be pursued, though the environ-
mental conflicts will probably be more difficult to resolve.
Either project would be a supplemental, not independent,
source of power for your community, as neither would ade-
quately meet the anticipated, future power needs. However,
in view of rising fuel costs and the uncertain supply of
power from a distant source, a hydroelectric project would
certainly decrease the city's dependency on a distant power
supply.
10.
Anchorage Office
310 K Street, Anchorage, Alaska 99501 907/279-6491
Vk
HIGHSMITH 42-M PRINTED IN U.S.A.
Mr. Johnny Johnson
5 March 1979
K12404.A0
Page Two
If you wish to pursue a hydroelectric project, the next
phase of action would be preparation of a Federal Energy
Regulatory Commission (FERC) permit application and to
proceed with a preliminary design for a detailed analysis of
the site.
Please call if you have any questions. Also, we can easily
arrange a presentation of this report if it would be helpful.
We enjoyed completing this study and appreciate the invaluable
help from the city staff.
Sincerely,
Corby H. Howell
Project Administrator
dea
enclosure
CITY OF SEWARD
RECONNAISSANCE STUDY OF HYDROELECTRIC POWER ALTERNATIVES
CONCLUSIONS AND RECOMMENDATIONS
In this study, the proposed Grant Lake project was found to
be the best hydroelectric alternative for a power source,
from economic and environmental standpoints. At this
reconnaissance level, examination revealed Crescent Lake as
the second most desirable site. It is recommended that the
City of Seward strongly consider the Grant Lake site as a
possible alternative for a supplemental power source for
their community. The Crescent Lake site might also be
considered, though the environmental conflicts associated
with this proposed project will be more difficult to resolve.
INTRODUCTION
The City of Seward now purchases power wholesale from
Chugach Electric Association (CEA); the city owns and
maintains standby generators only. On 15 January 1979, CEA
notified Seward that the contract determining the quantities
of and charges for the electric power and energy furnished
to Seward was terminated, under terms of the contract itself,
on 22 August 1972. CEA stated that power sales to Seward
subsequent to that date have not been and are not now con-
tractually mandated.
With substantial growth in the Seward area expected and the
price of the present wholesale power supply rising due to
increasing fuel costs, city officials have decided to investi-
gate the possibility of generating electricity with their
own facilities.
PURPOSE
To assist the city in determining what direction to pursue
for investigating and evaluating hydroelectric power, CH2M
HILL was retained to examine several previously identified
potential hydropower sites. These sites were ranked in
order of highest potential, economically and environmentally,
and the best site was recommended for city action.
- 1 -
METHOD
Four sites having generation potential were selected based
upon suitable physical conditions for producing energy.
Location maps are on pages 3 through 6. These conditions
included topography (for adequate height of water storage),
hydrology (for adequate water flow and availability), and
location (for proximity to existing transmission lines and
access roads). After the sites were identified, these
factors were further investigated using existing data,
updating when necessary. This information is presented in
the chart on page 7. This includes comparison of power
potential, dam height, reservoir storage, and transmission/
road access.
The Alaska Department of Fish & Game and the U.S. Forest
Service were contacted and asked to identify conflicts and
problems which could impact the construction of each hydro-
electric site and to rank the sites based on acceptability.
These points are also noted in the aforementioned chart.
The cost data presented in the comparative chart were taken
from reports referenced in the Bibliography. The costs were
updated according to the Engineering News -Record Cost
Index. The estimates for the Grant Lake alternative were
updated in 1978 by CH2M HILL on a Unit Price Basis. These
costs are for comparative purposes only and require further
refinement for establishing budgets.
- 2 -
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Site
(In Ranking order)
Grant Lake
Dam 50 ft. high
Res. 75,000 ac, ft.
W. S. Elev. 740 ft.
Mean head 250 ft.
Regulated flow 170 cfa
Crescent Lake
Dam 50 ft. high
Res. 50,000 ac. ft.
W. S. Elev. 1,485 ft.
Mean head 1,000 ft.
Carter Lake dam 15 ft. high
Regulated flow 40 cfs
Resurrection River
Dam 195 ft. high
Res. 168,000 ac. ft.
W. S. Elev. 425 ft.
Mean head 300 ft.
Average flow 400 cfs
Snow River
Dam 325 ft. high
Res. 134,000 ac. ft.
W. S. Elev. 1,200 ft.
Mean head 740 ft.
Average flow 600 cfs
Access
Road
1 mile
125 ft. bridge
No present road
Trail exists from
Moose Pass to lake
a miles
No present road
Trails exist into both
Crescent and Carter
Lakes
Transmission
Line
Capacity
Installed kW Land
kWh/yr ownership
1 mile 6, 000 kW Chugach National Forest;
Tie to Chugach 25 kV line 25.2 x 106 kWh/yr a further planning area
+ 4 miles north of Seward -
Chugach terminal
1 mile 5,500 - 6,000 kW Chugach National Forest;
Tie to Chugach 25 kV line 24.3 x 106 kWh/yr a further planning area
+10 miles north of Seward -
Chugach terminal
Exists for about 5 miles 7 miles
out of Seward. Could be 69 kV
easily developed from (initial 25 kV)
there. To new Seward substation
2 additional miles needed
3 miles 3 miles
No present road 69 kV
+Bridge Tie to Seward trans -
+Railroad crossing mission line
No structures now exist +11 miles north of Seward
Reconnaissance
Cost Estimate
$0.040/kW
r
$0.065/kW
17, 800 kW East side - Chugach National $0.166/kW
85.8 x 106 kWh/yr Forest; a further planning
classification. West side -
public domain or Fish &
Wildlife land under BUM
dt
Impacts
Environmental
Unresolved
Factors
Sheep & goat habitat. Creek Some sediment from
supports sockeye L king glacial streams.
salmon, close to lake
outlet.
Recreational area (grayling)
sheep & goat habitat.
Outlet stream supports king,
sockeye & coho salmon.
Important anadromous fish
stream w/coho, chum &
king salmon. Supports
moose and bear habitat.
eii
lur s s on
62, 800 kg All Chugach National Forest $0.056/kW lmpurtant big gmna habitat
275 x 10 kWh/yr Upper portion - proposed Unacceptable to Fish &
non -wilderness. Lower Game (State).
portion - further planning NOTE: Total project
area cost would be approxi-
mately $128,000,000
- 7 -
Some sediment from
glacial streams.
Heavy sediment load.
Some avalanche problems.
Very broad valley.
Effect of glacial outbreak
flood on reservoir. Flood
protection benefit. Heavy
scouring.
SITE SPECIFICS
Sites are presented in order of potential.
Grant Lake: The dam for this site would be built at the
outlet of the lake, with a crest length of about 550 feet,
and a height of 50 feet. A small saddle dam would be
needed. Approximately 75,000 acre-feet would be required
for complete regulation of the 170 cfs flow. One mile of
pipeline with about 800 feet of penstock would achieve an
approximate mean head of 250 feet. Average power output
would be 3,000 kW, with an installed capacity of 6,000 kW.
The dam site is approximately one mile from the Seward
Highway and the Alaska Railroad.
Alaska Fish & Game ranked this site #1, as the project most
likely to be acceptable from the environmental viewpoint.
Grant Lake is an important sheep and goat habitat. The
outlet creek supports -some sockeye and king salmon. These
conflicts would need to be resolved.
Grant Lake is presently in the Chugach National Forest. A
permit, from the U.S. Forest Service, for the project would
be required. The State of Alaska has selected land around
Moose Pass in accordance with the Statehood Act of 1958, but
it has not yet been conveyed to the state by BLM. This
selection includes land on both sides of the Seward Highway,
west of Grant Lake. A state permit would also be required
for any access to the project site, after the conveyance has
occurred.
Crescent Lake: Many schemes have been suggested for this
site; the most likely plan is to raise the level of the lake
enough to reverse the flow into Carter Lake and out Carter
Creek. Another consideration would be to tap the lake and
lower it. The reverse -flow plan is presently the most
economical. The Crescent Lake power plant would be about 31
miles north of Seward on the Seward Highway.
The dam crest would be approximately 1,000 feet long and a
5- to 10-foot cut would be made between Crescent and Carter
Lakes. A 15-foot dam would be built on the outlet of Carter,
as well as the 50-foot dam on Crescent Lake. The average
head would be about 1,000 feet with an average regulated
flow of 40 cfs, an average power output of 2,770 kW, and an
installed capacity of 5,500-6,000 kW. Reservoir capacity
would be 50,000 acre-feet.
Alaska Fish & Game ranked this project #2 in probable accept-
ability, though some areas of conflict need to be resolved.
The site is an important recreational area, is a sheep and
goat habitat, and the outlet stream supports king, sockeye
and coho salmon.
Crescent Lake is located in the Chugach National Forest, and
a permit for construction from the U.S. Forest Service would
be required.
Resurrection River: The dam site would be located approxi-
mately seven miles northwest of Seward, about one-third mile
below where Paradise Creek flows into Resurrection River.
The most likely plan would be a concrete gravity dam, with a
height of 195 feet and a crest length of 1,950 feet.
Elevation 425 feet would be the maximum water surface
elevation. A 22,000 foot tunnel would be constructed to
carry water downstream to a power plant with a tailwater
elevation of 100 feet. Reservoir capacity would be 168,000
acre-feet; average power output would be 6,900 kW, with an
installed capacity of 17,800 kW. Average flow would be
400 cfs. The spillway might be a 100,000 cfs capacity.
Resurrection River was ranked #3 by Fish & Game. The area
supports moose and bear. It is also an important anadromous
fish stream for coho, chum and king salmon. These conflicts
could possibly be resolved.
Resurrection River is the division line between Chugach
National Forest and land controlled by the Bureau of Land
Management. The BLM land has recently been withdrawn as a
national monument, which may preclude any construction. If
a project is possible, the permit would be issued by BLM,
with U.S. Forest Service approval.
Snow River: The dam site is located at a deep, narrow gorge
on Snow River, approximately 9 miles upstream of Kenai Lake
and 4.8 miles upstream of the Alaska Railroad. The dam
would be 325 feet high with a crest length of approximately
820 feet. Normal maximum water surface would be at elevation
1,200 feet and would require two small auxiliary dams to
close two saddles under 1200 feet. This would inundate
Lower Paradise Lake. Average flow is about 600 cfs for an
average power output of 31,400 kW, with an installed capacity
of 62,800 kW.
A tunnel 1.9 miles long with 0.4 miles of penstock would
connect the reservoir and the power plant.
- 9 -
Debris may accumulate in the reservoir due to glacial outbreak
floods or avalanches. This area has possible strong seismic
activity. Also, the spillway must be designed for the
glacial outbreak flooding which would be around 200,000 cfs.
Fish & Game rated this site #4 and -the conflicts could
probably not be resolved. The area is a big game habitat,
with high recreational value.
The area is in the Chugach National Forest. No withdrawals
have been made in this area. A permit would be required
from the U.S. Forest Service.
- 10 -
BIBLIOGRAPHY
A
lication for License for Crescent Lake H
Project, Before the Federal Power Comm
Seward, Alaska, Applicant, Project No.
Harstad & Associates, 1956.
droelectric
ssion, City of
2171, Howard T.
Indermukle, Vernon C., Preliminary Report on the Water
power Possibilities of Snow River, Nellie Juan Lake
and Lost Lake, Kenai Peninsula, Alaska, U.S. Geological
Survey, OF-61-1, 1961.
Johnson, Arthur, The Potential Waterpower of Grant,
Ptarmigan, Cooper and Crescent Lakes, U.S. Department
of the Interior, Geological Survey Open File, June
1955.
Lamke, R. D. and Scully, D. R., "Snow River Flood - 1974",
Water Resources Division, U.S. Geological Survey,
1-23-75, unpublished.
Scour at Selected Bridge Sites in Alaska, U.S. Geological
Survey, Water Resources Investigations 32-75, 1975.
Selected information from the files of the Alaska Power
Administration.
rnMTArTq
Our thanks to the following people for their contributions
to this report.
Mr. Bruce Barrett
Alaska Department of Fish & Game
Mr. Don Gotshall
U-S. Department of Energy
Alaska Power Administration
Mr. Charles Harnish
U.S. Forest Service
Mr. Ted McHenry
Alaska Department of Fish & Game
Mr. Tom Murdock
U.S. Army Corps of Engineers
Mr. Maynard Nuss
U.S. Forest Service
Mr. Weldon Opp
U.S. Army Corps of Engineers
Mr. Dale Rusnell
Alaska Division of Power & Energy Development
�� CH2M HILL
EXPLANATORY NOTES - CRESCENT LAKE HYDRO SURVEY
It is important to understand certain terminologies related
to hydroelectric projects in general, to understand findings
for specific hydrologic site investigations such as Grant
and Crescent Lakes.
Capacity is a term used to describe the rate of power (kW)
that can be obtained at any given time from a project.
Obviously the turbine -generator sizes to be installed are
optimized for maximum capacity related to the sustained
capacity. It is not peak demand but average annual energy
produced that must determine economic feasibility of a
project.
Primary Energy is a term that describes this annual average
energy available. It converts the average runoff and
impoundment capabilities of the hydro project to usable
annual kilowatt hours to be sold.
Load Factor describes the pattern of energy use (kWh) of a
community related to the maximum demand (M . Typically
Alaskan communities have ranges of 50%-70% load factors.
The ideal hydro project for a community shows a good match
between the annual runoff water energy (Primary Energy) and
the community Load Factor energy use pattern. This allows
design of specifics (dams, spillways, generator sizes, head,
etc.) "tailored" to the community.
Using Crescent Lake as an example, with development as
described in the CH2M HILL Reconnaissance Study (5 March
1979) the optimum development would have an installed
capacity of 6,000 kW and Primary Power of about 2,800 kW.
This means it could deliver 2,800 kW year round. At a
higher installed power output the project still could not
sustain more than this 2,800 kW as a year round average.
Estimates for Crescent Lake in previous years which show
higher installed capacities do not suggest that this average
2,800 kW capability is significantly greater, particularly
in view of the accumulated water records since those earlier
estimates (1954). The present estimates for Crescent Lake
indicate a regulated flow of about 40 cfs against 1954
estimates of a hopeful 70 cfs. The intervening 25 years
have hardened the water record and decreased the prudent
development capacity of the Crescent Lake project.
ME
ME CH2M HILL
• CFS = cubic feet/second of water runoff
• H = "head" = height in feet (average) of water above
generating turbines
• "Prime Power" is approximated by:
PP = (Average annual CFS) x-(H) x (0.07)
PP = kW = kilowatts capacity in this formula
• Primary Energy = (Prime Power) x (8,760 hrs/year)
PE = kWh energy in this formula
• "Load Factor" is a term describing the energy use pattern
of a particular community.
Load Factor = L.F. = actual annual kWh energy
peak demand (kW) x 8,760 hrs
L.F. = kWh = dimensionless factor