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• Board Meeting Date: 7/11/2007
• Description: ISF Section - Hat Creek Water Right Acquisition
• Board Meetings - Doc Type: Memo

P. Fritz Holleman, Esq.
January 25, 2006
Page 3

I understand that if accepted, the water right would be used by the CWCB for instream flow
purposes. The water right could be changed firstly to instream flow uses on Hat Creek. Most of the
return flows accrue to East Brush Creek so the historical depletion to Hat Creek is equal to the
diversion rate, 2.0 cfs.

Secondly the historical stream depletion rates or the historical consumptive use amounts
could be assigned to East Brush Creek and Brush Creek and the amounts passed downstream.
The following depletion rates are taken from row 15 of Table 2 and the historical consumptive use
rates are derived from the monthly volumes shown in row 7 of Table 2.

Month
May
June
July
August
September
October
November

Depletion lcfs)
0.04
0.31
0.17
0.07
0.05
-0.03
-0.02

Historical Consumptive Use lcfs)
0.09
0.16
0.13
0.10
0.09
0.12
0.00

If reductions in the historical consumptive use are necessary due to non use in 16 years of the
study period the depletion and historical consumptive use rates would be 41 percent less than the
monthly values shown above. The Division Engineer may be compelled to charge transit loss
against the monthly rates in amounts depending on how far downstream the CWCB transports the
water.

Summary

1. The Hat Creek Ditch diverted water for irrigation purposes from Hat Creek, a tributary of
East Brush Creek, Brush Creek, and the Eagle River. Its water right for 2.0 cfs with an
appropriation date of March 6, 1914 was decreed in Civil Action No. 673 by the Eagle
County District Court on July 17,1916.

2. For 1951 through 2004, the diversion records show water diverted in 23 years, no water
diverted in 16 years, and no information available in 15 years. For the 23 years with
records, the diversions averaged 230 acre-feet annually and ranged from 55 acre-feet in
1992 to 566 acre-feet in 1984. With inclusion of the 16 years showing no diversions, the
average decreases to 136 acre-feet annually.

3. The irrigated acreage is 22 acres or less based on inspection of an aerial photograph.
Field inspections would be needed to better identify the irrigated acreage and configuration
of the irrigation system.

4. A water budget shows that there was a full water supply available to the Hat Creek Ditch.
Using the diversion amounts for those years with diversions, 23 years, the historical
consumptive use averaged 35.4 acre-feet annually. The stream depletions, diversions
minus return flows, varied monthly during the irrigation season from 0.04 cfs in May to 0.31
cfs in June. In October and November, return flows exceed diversions so there is a net
accretion of 0.03 cfs and 0.02 cfs, respectively. The lag is caused by the factors used to
delay the ground water return flows. If years of non-use must be considered, the historical
consumptive use and stream depletions would have to be reduced by 41 percent.