WSP00886

• File Number: 8407
• Description: Platte River Basin - River Basin General Publications
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 4/16/1990
• Author: BOR
• Title: Annual Operating Plans - North Platte Project Water Years 1989-1990
• Water Supply Pro - Doc Type: Report/Study

Colorado~ Thompson Project

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Reasonable Mlnimum Inflow Forecast

Green Mountain Reservoir

If reasonable minimum inflow is forecasted on February 1, releases from
the reservoir for bypass of inflow, power, replaCement, and reservoir
regulation will be scheduled in March to bring storage to about
75,UOO acre-feet by April 30. During May and June, releases will be held
at 60 ft3/s to satisfy downstream water rights on the Blue River. With
reasonab 1 e mi nimum runoff, it is est imated that Colorado Spri ngs and Denver
will deplete the Blue River by about 69,500 acre-feet during the
April-July period. The depletions will cause about 14 gigawatt-hours of
power interference at Green Mountai n Powerp 1 ant. Releases duri ng Ju ly
through September wi 11 be made to bypass inflow, for repl acement of
Project depletions, and for natural flow shortage to west slope irrigation
and domestic users. Carryover storage at the end of the water year
will be 28,400 acre-feet below the 30-year average at 100,000 acre-feet.

Willow Creek Reservoir

If reasonable minimum runoff develops, Willow Creek Reservoir will fill
to the content of 8,300 acre-feet by the end of March. This is
1,900 acre-feet below maximum reservoir storage. All water in excess of
downstream requirements will be pumped to Lake Granby, totaling
20,300 acre-feet during the April-July period. With minimum required
releases to the river, carryover storage of about 9,000 acre-feet will
remain at tile end of the water year.

Lake Granby

Storage in Lake Granby will be lowered to 127,700 acre-feet by the. end
of March. With minimum inflow, Lake Granby will refill to a maximum of
182,400 acre-feet by the end of June, which is 357,400 acre-feet below
maximum storage capacity. Adams Tunnel diversions during February
through September will be above average to provide adequate irrigation
de 1 i veri es in the Proj ect area. September 30 carryover storage of
120,200 acre-feet would be only 29 percent of normal, and
46,000 acre-feet above dead storage.

East Slope/Colorado-Big Thompson Project

With reasonable minimum inflow forecast on February 1, an above-normal
supplemental irrigation demand equal to 333,200 acre-feet can be
expected on the Proj ect. Divers ions through Adams Tunne 1 wi 11 be at
capacity of 550 ft3/s from February 1 through March 20. This will bring
Carter Lake storage to a total of 95,100 acre-feet, which is 85 percent
of the tota 1 a 11 owab 1 e storage capacity in Carter Lake. Adams Tunnel
and Olympus Tunnel diversions will be minimized from March 21 through
April 28 to accommodate the Pole Hill Canal, Afterbay, and Powerplant
ma i ntenance schedu 1 ed duri ng th is peri od. Horsetooth Reservoi r wi 11
reach a maximum storage of 135,100 acre-feet by the end of June, which
is 21,600 acre-feet below the reservoir capacity.

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