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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 2

Other water rights formerly owned by Kummer Development Corporation were included in
Case Nos. 81 CW479 and 93CW305. I studied both decrees and found no mention of the Hat
Creek Ditch or any decree provisions that may affect the past and future use of the Hat Creek
Ditch.

Historical Consumptive Use

Table 2 presents a historical water budget for the Hat Creek Ditch using the average
monthly diversion values for the 23 years when diversions were recorded. Components of the
water budget are explained and references are noted in the table's footnotes. The water budget
calculates the consumptive irrigation requirement for 22 acres of hay and pasture grass and
compares that with the water supplied by the Hat Creek Ditch. The diversions totaled 230.3 acre-
feet and the consumptive use totaled 35.4 acre-feet. The remainder of the water returned to East
Brush Creek directly as tail water or via the ground water. East Brush Creek is close to the
irrigated fields, so the ground water returns were lagged 75 percent to the month that the water
was diverted from Hat Creek and 25 percent to the following month.

The stream depletion is the difference between the diversion and return flow amounts as
shown in row 14 of the water budget. On an annual basis, the stream depletion equals the
consumptive use. The monthly net depletions range from 0.04 cfs in May to 0.31 cfs in June. In
October and November, the return flow exceeded the diversions resulting in stream accretions; the
accretions were caused by lagging the ground water return flows in the manner described above.

I understand that the Division Engineer has taken the position that the historical
consumptive use should be reduced for years that there were no diversions as recorded by the
Water Commissioner. From 1951 through 2004, diversion amounts for the Hat Creek Ditch were
recorded in the 23 years. There were no diversions in 16 years and no information available in 15
years. Including the no-diversion years in the average as 0 acre-feet of historical consumptive use,
the historical consumptive use and stream depletion would reduce to 20.9 acre-feet annually, a
reduction of 41 percent. The monthly volumes and rates likewise would decrease by 41 percent.

Green Mountain Reservoir

The Hat Creek Ditch water right is junior to the principal water right for the Shoshone
Powerplant. Historically, annual water was released from Green Mountain Reservoir for the benefit
of West Slope users. This benefit was quantified by the Bureau of Reclamation in its operating
policy as 66,000 acre-feet and this amount is reserved for West Slope users in the "Historic Users
Pool". Part of this released water replaced the out-of-priority depletions of West Slope users
located above the Shoshone Powerplant. The Hat Creek Ditch benefited to some degree in some
years from the Green Mountain Reservoir releases by replacing the depletions with respect to the
Shoshone Powerplant call but the amount of such benefit is difficult to quantify.

The water right for the Hat Creek Ditch is a moderately senior water right in the Brush
Creek basin. I am unaware of any call records for Brush Creek but I suspect that in a dry year the
Hat Creek Ditch water right could be called out of priority in the mid to late summer by downstream
senior rights on Brush Creek although the diversion records do not prove this proposition correct.
The diversion records for 1977, considered to be a very dry year, shows that the Hat Creek Ditch
diverted a total of 114 acre-feet from June 22 through September 25 at rates up to 0.6 cfs.

Potential Use of the Water Right by CWCS