WSP01847

• File Number: 8449.900
• Description: Bear Creek
• State: CO
• Basin: South Platte
• Date: 4/1/1979
• Author: Evergreen Sanit.
• Title: Water Resources Study, Evergreen Water System
• Water Supply Pro - Doc Type: Publication

:

Curtailment of Irrigation would not completely alleviate the shortages

in this case since the supply f~ll below the base use on 3 days.

The provision of approximately 55 acre-feet of raw water storage would

supply the shortage for the entire drought plus 10% for evaporation

and other losses. Detention storage would also be a way to equalize

the temporary shortage. This storage is generally undecreed forebay

storage at municipal treatment plants and is allowed for fire and

other disasterous occurrenceS that may affect a municipal water supply

to the detriment of the health and welfare of the public.

A recurrence of either the 1963 drought or 1978 drought, both of

which have an average frequency of occurence of once in 100 years

or less, would impose much more severe demands on the water system.

Under the assumed competing condition for water, the Evergreen system

would not meet demands during a recurrence of either of these drought

for the present number of 2,390 equivalent taps. Even base use could

not be met on 7 days during July for a McBroom Ditch call of 6 cfs

and on 36 days during June, July and August for a McBroom Ditch call

of 10.6 cfs, and ass.uming 1963 drought conditi.ons.

A demand of 4,000 taps could be met for the 1963 drought by providing
163 acre-feet of raw ~ater storage for the 6 cfs McBroom Ditch call
or 296 acre-feet for a call of 10.6 cfs. These storage figures include
10% for losses.

The Evergreen system met the demand during the 1978 drought but

under assumed future conditions, this would not be possible. The

main reasons for the Evergreen rights not being curtailed is that

the McBroom Ditch did not call its right, and the remaining No.2

priority water right, mined by the Denver ~Iater Board was not diverting.

The calculations of shortages presentee herein include diversion of

only 47% of the water available to the ~0.2 priority when the supply

would not satisfy the full right. In essence, since there were no

senior calls in 1978, the supply at Evergreen ~:as ah1ays io excess

of the demand, and proportioning of water to the No.2 priority water

right was not required.

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