BOARD00447

• Board Meeting Date: 9/13/2005
• Description: ISF Section - Rehabilitation of Meridian Lake by Upper Gunnison Water Conservancy District
• Board Meetings - Doc Type: Memo

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BRATTON & McCLOW LLC

Linda J. Bassi
Stream and Lake Protection Program
Colorado Water Conservation Board
August 22, 2005
Page 2

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work a few days later. The rehabilitation work includes replacement of the existing outlet works
(which are primitive) with a new outlet/spillway pipe and stilling basin, installation of a new release
valve and hand wheel, installation of a new Parshall flume and installation of a siphon, all according
to plans approved by the State Engineer. The siphon will provide access to 175 acre-feet of decreed
live storage which cannot be released using the existing outlet works. The rehabilitation, although
not required by the decree, will make operation and administration of the plan tor augmentation more
efficient and reliable, and thus will benefit both the protected wells and the senior water rights
receiving deliveries of replacement water, including the CWCB instream flow rights.

We contacted you because, as pointed out above, the District is concerned about the
possibility of diminished flows in the Slate River this Fall that could result in a shortage to the
CWCB instream flow rights, permitting a call for Meridian Lake Reservoir water under the plan for
augmentation when the dam rehabilitation is in progress. Studying the current and historical gauge
records for that reach of the Slate River, it appears that such a shortage is not probable, but certainly
possible, most likely in October or November. (The rehabilitation is scheduled to be completed on .
October 15, but whether any storage will occur during October that would enable releases is
unknown.)

The evacuation of the reservoir required for rehabilitation of the dam will preclude a release
of winter mitigation storage this Fall, should the CWCB decide to request such a release after
October I pursuant to paragraph 55 of the decree approving the District's plan for augmentation.
The District requests that the CWCB accept the current release of the entire active storage content
of the Reservoir (approximately 400 acre-feet) in lieu of a winter mitigation release later in the year.

The District has attempted, without suc.;ess, to obtain an alternati ve source for replacement
water during the rehabilitation period. Therefore the Upper Gunnison District requests that the
CWCB agree to forbear calling its instream flow water right in the Slate River during the period
when the reservoir is undergoing rehabilitation. That period will be relatively short, because the
settlement with the CWCB incorporated in the decree does not contemplate releases during the
winter months, which begin in November in most years. Furthermore, the potential depletion during
this period from the wells currently protected by the plan for augmentation is very small, and if it
occurs, should have no lasting impact on the environment protected by the instream flow right.

To help you evaluate the potential depletion, I have attached a table that calculates the
amount that the protected wells will deplete the stream on a daily basis, using the depletion amounts
incorporated into the decree for the plan for augmentation. At this date, the Upper Gunnison District

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