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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terminal r-eser-voir- stor-age. Carter- Lake
95,200 acr-e-feet for- the water- year
17,000 acre-feet below capacity.

During the Mar-ch 21 through April 28 per-iod, Adams Tunnel and Olympus
Tunnel diversions will be minimized to accommodate the Pole Hill Canal,
Afterbay, and Powerplant maintenance scheduled. As runoff develops in
1ate Apr-i1 and May, Adams Tunnel diversions will be adjusted to
accommodate runoff timing on the east and west slopes.

storage will reach a maximum of
in late Mar-ch, and this is

Horsetooth ~eservoir is expected to reach a storage content of
127,800 acre-feet by the end of May, which is 28,900 acr-e-feet below the
maximum r-eservoir storage of 156,700 acr-e-feet. Restrictions on the
filling of Horsetooth Reservoir were lifted on November 27, 1989, and
the reservoir may now be oper-ated to the design maximum water- surface
elevation of 5430.00 feet (156,700 acre-feet).

Dur-ing April and June, a total of 7,600 acre-feet will be r-eleased fr-om
Carter- Lake to Flatir-on Reser-voir. This r-elease is necessary to meet
the 8ig Thompson irrigation demands and the minimum inflow to Horsetooth
Reservoir during the Pole Hill maintenance and when "skim" water
diversions are at capacity.

Adams Tunnel diversion will be down to 7,300 acre-feet in June to take
full advantage of operation "skim". Under- oper-ation "skim",
approximately 49,200 acre-feet of 8ig Thompson River- water- will be
di verted at Lake Estes through the Foothi 11 s System duri ng Apr il-September.
The majority of "skim" water (46,400 acre-feet) wi 11 be diver-ted during
May, June, and July.

Irrigation demands will draft Hor-setooth Reser-voir- stor-age to
approx imate ly 69, 700 acr-e-feet by September 30. A tota 1 of
10,400 acre-feet will be pumped to Car-ter- Lake from May thr-ough September
which wi 11 bring Carter Lake storage to near- 35,000 acre-feet. The
combined east slope terminal storage will be 86 per-cent of nor-mal at the
end of the water year.

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