PROJ00090

• Contract/PO #: FS0015X
• Contractor Name: Powderhorn Metropolitan District No. 1 and No. 2
• Contract Type: Loan
• Water District: 0
• County: Mesa
• Loan Projects - Doc Type: Feasibility Study

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JAN 10 '97 03:12PM CALOIA & HOUPT, P.C.

P.2

ii!iE A E SOU R C E
.....
..... e N C3 I NeE R I N GIN C .

Mr. Jeff Houpt
Calois and Houpt, P.C.
1204 Grand Avenue
Glenwood Springs CO 81601

January 10, 1997

RE: Powderhorn - Robbins Reservoir

Dear Jeff:

At your request Resource Engineering, Inc. conduoted a yield analysis tor Robbins
Reservoir. The analysis was based on the assumption that the reservoir would be
constructed with an active capacitY of 50 acre feet and that it would operate as
augmentation ~tori!ge for Powderhorn Resort. It would provide augmentation releases
fOT ou't-ot-prloritV depletions not augmented by other sources, including those
associa'l:ecl with the domestic needs of a 1,300 EaR development described in Case No.
86CW01'S as well as snowmaking and other irrigation demands.

The reservoir Is located on Big Beaver Creek downstream from most of the proposed
development and above the confluence with Mesa Creek.' The location of the Robbins
Reservoir is ideally situated fO,r augmentation of Powderhorn depletions and provides
adv!/"Iteges over it's other augment8tion sources. It can fill and refill in-priority and
store water by exchange under water rights decreed In Division 5 Water Court.

The reservoir can be operated in sueh a manner as to provide at least 'two fills per year.
'The total yield wjll be a minimum of 100 acre feet per year. The first fill would occur
during the spring runoff (April.Mayl.This is a period when there Is no call on the
reservoir's water right and there I! adequate flow in Big Beaver Creek. Mean monthly
flow during the peak runoff peiiod is estimated to be 10 tc 1.4 efs which can fill the 50
AF reservoir in matter of a few days.

The reservoir can 'eMn be emptied during the irrigation season to replace Powderhorn's
out-of-priority depletions assdeiated with tne domestic and irrigation uses.

Robbins ReservoIr c:an then be refilled during the later irrigation season by exchanging
watar released from Mesa Lakes or under its own priority during the. month of October
when irrigation demand ceases and prior to snowmaldng. The estimated mean flow
rate during October is 2.6 efa which can fill the reservoIr in about 10 days.

The 50 AF refill can then b! released throughout the winter months to replace domestic
and snowrnaking depletions. .

The net yield of the fill and refill of Robbins Reservoir when operated in thIs manner is
100 AF/yr. The reservoir operation is shown in the ,following table.

Consult;ing engineers. ~iInd Hydrologists,
90S Color~c:lo Avenue . Glen~oc;l Spring~, 9081601 . (970) 945-67'77 . FaX" [phone]

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