HomeMy WebLinkAboutLake Elva Reconnaissance Study June 1979I
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RECEIVED,
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rity ~ POWER AUIHORI11J
RECONNAISSANCE STUDY OF THE
LAKE ELVA
AND
OTHER HYDROE~ECTRIC POWER PQTENTIAL
IN THE
DILLINGHAM AREA
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ROBERT W. RETHERFORD ASSOCIATES
CONSULTING ENGINEERS
A DIVISION OF INTERNATIONAL ENGINEERING CO., INC.
ANCHORAGE, ALASKA
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RECONNAISSANCE STUDY OF THE
LAKE ELVA
AND
OTHER HYDROELECTRIC POWER POTENTIAL
IN THE
DILLINGHAM AREA
SUPPLEMENTAL REPORT
Prepared for
ALASKA POWER AUTHORITY
Prepared by
ROBERT W. RETHERFORD ASSOCIATES
A DIVISION OF INTERNATIONAL ENGINEERING C0~1PANY, INC.
ANCHORAGE, ALASKA
JUNE 1980
A. INTRODUCTION AND SUMMARY
This report has been prepared to supp 1 ement the reconnaissance
study of February 1980 with hydrological data obtained by the Water
Resource Division of the U.S. Geological Survey for lake Elva and
the Tazimina River. Gauging data had not previously been available
for these two locations and the estimated data used in the original
study had been developed by correlating with data from gauged
streams and their drainage areas in the vicinity.
The field data available now does not warrant a re-evaluation for
any of the potential development sites at this time.
B. LAKE ELVA HYDROELECTRIC POWER POTENTIAL
The potential at lake Elva has been calculated to be 910 kW or
7,972 MWh of firm energy per year for a mean effective head of
260 feet and an assumed average flow of 50 cfs or an annual discharge
of 36,198 acre-feet.
A stream gauge was installed by the U.S.G.S. Water Resource Division
in the fall of 1979 providing stage data for October and November
(See Exhibit A). Discharge measurements were taken in November.
January, and April of the winter 1979/80. Monthly discharge estimates
for the time from October to April were then prepared by the U.S.G.S.
using the data obtained and correlating with other gauging data
from the area. Table I 11 Lake Elva -Monthly Discharge" shows a
comparison of these estimates with the synthesized flow developed
for the report.
Since all discharge calculations are based on estimates, a re-
evaluation of the project is not considered necessary at this time.
With development of the site planned in the near future the installed
capacity has to be determined in a detailed feasibility study.
apal/t - 1 -
20-YEAR AVERAGE
(RWRA-REPORT)
Discharge
Flow
16.9
275
24.5
441
33.4
543
U.S.G.S. MEASUREMENTS 3 01/11/80 02/27/80
Flow 290 302
1 Not calculated.
2 7 months average: RWRA Report 28 cfs
U.S.G.S. Estimate 19 cfs
3 Taken approximately 3 miles upstream from damsite.
TAZIMINA RIVER
75.6
1,270
115.7 148.2 163.6 160.4 135.9 90.4 52.9 13.6
1,882 2,490 2,661 2,609 2,284 1,470 889 221
1,031
1,424
Heavy snowfall during the winter 1979/80 resulted in increased
avalanche activity. The stream gauging station was found inundated
by avalanches in April 1980. Figure I 11 Lake Elva Project11 shows
the location of the gauging station in relation to the planned
project facilities. It is not expected that avalanches will occur
where the dam, pipeline, penstock and powerhouse are planned to be
located.
C. TAZIMINA RIVER HYDROELECTRIC POWER POTENTIAL
The potential at Lake Tazimina has been calculated to be 9 MW or
78,840 ~Mh of prime energy per year for a mean effective head of
184 feet and an assumed regula ted flow of 700 cfs or an annual
discharge of 506,776 acre-feet.
Stream gauging data are not available for this site except for two
flow measurements taken by the U.S.G.S. Water Resources Division in
January and February 1980. These measurements and the synthetic
discharge data developed for the report are shown on Table I 11 Lake
Elva/Tazimina River -Monthly Oischarge 11
• It is not possible to
draw conclusions from the two measurements which would lead to
recommendations for re-evaluation of the potential. The flow data
compares well with the estimates and indicate that the original
assumptions were reasonable.
To establish a firm data base it is recommended that a stream gauge
be installed as soon as practicable.
apa1/t - 3 -
LAKE
NERKA ...
0
ALASKA POWER AUTHORITY
LAKE ELVA PROJECT
I X 1.5MW
GENERAL PLAN & LOCATION
SCALE: I"=IMILE
N
DATE JUNE 1980 CCNTltACT 9703-3
FIGURE-I
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Ms Dora Gropp
Retherford Robert W. Associates
6927 Old Seward Hywy.
Anchorage, Alaska
Dear Dora:
.May 20, 1 980
Following you will find monthly discharge values for the period
October 1979 to April 1980 for Elva Creek at the outlet of Elva
lake and the Kisaralik River located In the NW 1/4 of sec. 17,
T3N, R61W. .
· OCT NOV DEC JAN FEB
Elva Creek 4,000 3,200 300 30 30
Kisaralik R.96,000 70,000 30,000 10,600 7,500
MAR
70
8,200
APR
sao
9,600
These values are only estimates and subject to revision. The
E 1 va Creek runoff data is based on some s taae d~b I e in
9.C::I.Qber and.Ji.ovember. w~ do. not. have sufficient open-water
measurements to define a stage~discharge relationship so the stage
data we did get served little more than an indicator of stream
fluctuation. The record after mid-November thro~~pril ~q~
estimated base~-on discharge measurements of 1.05 cfs and 10.2
cfs _made January 3 and April 9 res~ctively.
The total period for the Kisaralik River was estimated based on
stage record from the Snake River near Dillingham and discharge
measurements of 3500 cfs, 269 cfs, and 273 cfs made October 11,
January 31, and April 9 respectively.
Also for your information, discharge measurements of 290 cfs and --------302 cfs were made January 11 and February 27, respectively on the
_Is;~zlmlJ};:J __ ifL'le.J: -1 oca.ted at lat. 59 ° 56 1 07", 1 ong. 154 ° 36' 50", in
-s\TT/4Nfl71fsec 9, T3S, R31W, 12 miles upstream of mouth and
15 miles northeast of Iliamna.
Sincerely,
-~ ~ y __ ,.
-J ·.11/.\:'1 · 7 i,tU•t_./
"' ,f;; r ~Y ~ ~. Le~een
Acting Subdistrict Chief
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