WSP03460

• File Number: 8441.700
• Description: Colorado Big Thompson Project - Annual Operating Plans
• Basin: South Platte
• Water Division: 1
• Date: 1/1/1989
• Title: Annual Operating Plans - Colorado Big Thompson Project - Water Year 1989-1990
• Water Supply Pro - Doc Type: Report/Study

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totaled only 17,666 ac...e-feet fo... the yea.... This was only 43 percent of
the average 41,500 ac...e-feet annually diverted.

August precipitation and inflow at Lake Estes we...e nea... normal at
91 pe...cent of average and 93 percent of average, respectively. Total
p...ecipitation fo... the water year (October-September) was 14.95 inches 0'"
87 percent of average. The inflow above Lake Estes was 62,400 ac...e-feet
for water year 1989 and this was only 69 percent of average.

Estes Powe...plant generation totaled 122,200,000 kilowatt-hours fo... the
water yea... and was nea...ly 15,500,UOO kilowatt-hours above ave...age.
Thi s was due to the above-average Adams Tunnel di vers ions wh i ch were
118 percent of average.

Carte... Lake

Completed in 1952 wi th three dams, Ca...te... Lake has a total storage
capacity of 112,2UO acre-feet. Inflow of project water to Ca...ter Lake
is f...om the Flati...on Pumping Plant with a capacity of about 400 ft3/s.

Carter Lake storage content at the beginning of the wate... year was
84,295 acre-feet which was above the 30-year average of 50,800 ac...e-feet.
Project water deliveries to the St. Vrain Canal continued through the
end of Octobe..., and totaled 6,823 ac...e-feet fo... the month.

Continuous pumping to Ca...ter Lake from Flatiron Reservoir continued
until late October to accommodate scheduled Charles Hansen Feeder
Canal(550 ft3/s section) maintenance during the October 1 to Octobe... 14
peri od. Pumpi ng to Ca...ter Lake was shut down on Octobe... 25 due to the
high deliveries (500 ft3/s) to the Big Thompson River. Pumping
continued on Novembe... 2, and this b...ought Carte... Lake storage to the
maximum fo... the wate... year of 112,321 ac...e-feet on Decembe... 21. This
was 0.08 feet above the normal maximum ope...ating level of 5759.00 feet.

All early fi 11 of Ca...ter Lake by the end of December 1988
allow for scheduled maintenance on the pressure tunnel.
tunnel was shut down from December 21, 1988, to June
pressure tunnel lining repai..., grouting, and F1atiron
maintenance.

was planned to
The pressu...e
15, 1989, for
Unit 3 annual

Irrigation delive...ies to the St. Vrain Canal began in early Apr-il. A
total of 3,6U5 acre-feet was delive...ed in April and 16,521 ac...e-feet in
May, including mete...ed delive...y. Water deliveries fo... June we...e much
above no...mal at 9,700 acre-feet. Pumping to Carte... Lake began a9ain on
June 15 and was scheduled as necessary to maintain the lake at a
desi...able ope...ating level.

Project wate... del iveries were much above ave...age in July at
33,OUO acre-feet, which was 202 percent of average. The end of water
year sto...age of 36,450 acre-feet was 14,350 acre-feet below no...mal.

Water year deliveries to the St. Vrain Canal totaled 100,400 acre-feet,
much above the 30-yea... average of 61,000 acre-feet.

Flatiron Unit 3 generation was not scheduled du...ing the water yea... due
to high P...oject deliveries. A total of only 33 acre-feet was delive...ed

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