WSP11259

• File Number: 8441
• Description: Colorado - Big Thompson - Green Mountain
• State: CO
• Basin: South Platte
• Date: 3/12/1985
• Author: CRWCD by West. Eng.
• Title: Green Mountain Reservoir Water Sales Impact on Flows in Gore Creek
• Water Supply Pro - Doc Type: Publication

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VVCWD Demands and Depletions

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According to ths VVCWD request, water from Green Mountain Reservoir will

be needed from November through April for municipal and snowmaking purposes.

The municipal diversions will require water from November through April during

all years. Snowmaking diversions require water from November through February

in dry and aveyage water years and November through December for wet years.

Water data for the above purposes was taken directly from the VVCWD request for

water service from Green Mountain Reservoir.

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Table 2 shows expected VVCWD depletions for assumed development conditions

and the related total diversion requirement. Total diversion requirements or

demand for municipal purposes were determined from the depletion data assuming

that replacement would be required only for the consumptive use associated with

the municipal water use (10% of diversion) and that 10% of the water released

from Green Mountain Reservoir would be lost in transit.

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Snowmaking demand was calculated from the requested water service amounts

as follows: (1) a 10% transit loss was assumed for all replacement releases

from Green Mountain Reservoir, and (2) the remaining water (in acre-feet per

month) was considered to be diverted and used for snowmaking. Bpcause the

snowmaking diversions result in a physical removal of water from the stream for

which there is no appreciable return flow until the spring runoff, it was

assumed. that the entire snowmaking diversion amount would have to be replaced

during the month such diversions were made.

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Based on the VVCWD application and information supplied by Tipton and

Kalmbach, all return flows from municipal diversions above Vail re-enter Gore

Creek (minus depletions) at the Vail Sewage Treatment Plant with no lag time.

The VVCWD municipal diversions below Vail re-enter the sy~tem (minus

depletions) at the Avon Sewage Treatment Plant. Snowmaking return flows were

assumed to re-enter Gore Creek via Mill Creek, but they were delayed until

April through July.

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The VVCWD has several locations from which it may divert water from Gore

Creek for municipal purposes. Snowmaking diversions from Gore Creek, however,

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