WSP08923

• File Number: 7630.225
• Description: Wild and Scenic-Elk River
• State: CO
• Date: 4/1/1979
• Author: Leonard Rice WatEng
• Title: Elk W and S Study-Hinman Park Res-Public Service Company of Colorado-Appraisal of Hinman Park Reservoir and Saddle Mountain Pump Stations Water Rights
• Water Supply Pro - Doc Type: Report/Study

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To facilitate extrapolation of recorded data from basins
of different areas. streamflow data were first reduced to
values of unit runoff (URO) expressed in inches. Correla-
tions were then developed and tested between the recorded
unit runoff for the index basins and such parameters as
mean elevation, snow water content and normal annual and
seasonal precipitation. From the analysis, it was found
that the best correlation could be developed betweeri annual
-unit runoff -and- the-weighted-average normal annualprecipita-
___~~9~_Q~er_~he pa~ins.____

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Several of the index basins did not have complete records
for the study period and it was necessary to complete the
records for these basins by using the URO vs. weighted nor-
mal annual precipitation correlations. Monthly runoff was
derived from the records of the Elk River at Clark and the
Yampa River near Steamboat Springs for the period 1930-1977
using the average of the monthly runoff as a percentage of
the annual runoff.

The results of the analysis are contained in Tables 4, 5 and
6 which show the generated monthly flows at the Hinman Park
Reservoir site (Table 4) and the Saddle Mountain Pump Sta-
tion diversion points from the Elk River (Table 5) and the
Ya..mgaRiver_ -(Table -6}- -at -their confluence. - - - - -

Analysis of these data indicates that the Hinman Park and
Saddle Mountain decrees will have a qependable physical
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supply of water. The annual runoff at the Hinman Park Res-
ervoir site exceeds the decreed amount in all years of the
study period including 1977, a year of near record low run-
off. Analysis of the generated runoff records indicates
that the 39,039 acre-feet ot active storage capacity will
furnish a dependable physical yield of 6,600 acre-feet per
month or the equivalent of 109 cfs released from the res-
ervoir on a continuous year-round basis.

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Leonard Rice Consuning Waler Engineer~ Ine,

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