FLOOD01459

• County: Gunnison
• Community: Uncompahgre Valley
• Title: Upper Gunnison-Uncompahgre Basin Phase 1 Feasibility Study Summary Report
• Date: 5/1/1989
• Prepared For: Colorado Water Resources and Power Development Authority
• Prepared By: HDR Engineering, Inc.
• Floodplain - Doc Type: Project

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capacities of the Aspinall Unit direct flow decrees are: Blue Mesa, 3500 cfs;
Morrow Point, 5450 cfs; and Crystal, 3000 cfs.

The depletions associated with each of these aggregated depletion demands
were derived from consumptive use calculations, estimates of irrigated acreage
served by specific ditches, diversion records, and detailed operating studies
of selected ditches. The depletions are allocated between water rights
priority classes at each aggregation point in proportion to the amount of
decreed rights in each class at each point, and the assumption that diversions
take place first under the more senior water rights.

3.5 INSTREAM FLOW DECREES MODELED

There are several reaches of the Gunnison River and its tributaries for
which minimum stream flows have been proposed or decreed. There is also
concern over i nstream fl ows for endangered species in the Colorado Ri ver.
These instream flow issues fall generally into four categories: 1) instream
flow decrees and recommendations of the Colorado Water Conservation Board
(CWCB), 2) privately held instream flow decrees, 3) potential minimum stream
flows associated with the proposed designation of the Gunnison River through
the Black Canyon as a wild and scenic river, and 4) instream flow goals as
stated in the Recovery Implementation Program For Endangered Fish Species in
the Upper Colorado River Basin prepared by the U.S. Fish and Wildlife Service.

The CWCB administers Colorado's Instream Flow/Natural Lake Level Program
pursuant to Section 37-92-102(3) of the Colorado Revised Statutes (C.R.S.).
The CWCB is authorized to make appl ications in the Water Court for minimum
streamflows and minimum lake levels which it determines to be necessary to
preserve the natural environment to a reasonable degree. The CWCB presently
holds or has applied for instream flow decrees on 180 stream reaches in the
Gunnison River Basin.

All of the CWCB decrees located on stream reaches downstream of existing
or proposed projects or downstream of existing diversions have been included