PROJ00492

• Contract/PO #: C153364
• Contractor Name: Beck, R. W. and Associates
• Water District: 0
• County: Garfield
• Bill Number: SB 81-439
• Loan Projects - Doc Type: Feasibility Study

include an estimate of the Probable Maximum Flood (PMF) for
the Colorado River at the Una site for spillway design, and
an estimate of frequencies of lesser floods for use in stud-
ies of river diversion during construction. Studies of sedi-
ment accumulation in the reservoir and the effect on storage
volume will be based on sediment data collected for the
Colorado River at the Una site and at other locations, and
acceptable procedures for estimating the distribution of
sediment within the reservoir.

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Conduct a water righta evaluation and storable water analy-
Si:3. The steps for this task are as follows:

- Generate a 30-year record of monthly virgin flows at the
Una site based on existing streamflow records and appropri-
ate adjustments for historic transmountain di versions and
upstream depletions.

- Develop estimates of future upstream water depletions and

downstream release requirementa based on senior conditional

water rights decrees and Federal water claims for three

eases of develolXllent of the senior decrees. Each case is

to be developed with and without the Placita Decree trans-

ferred to the Una site.

- Ganp.lte the storable flow available at the Una site by de-
ducting the upstream future water depletions and required
downstream releases from the 30-year record of virgin flows.

- Estimate effects of possible exchange arrangements between
upstream and downstream water users.

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Conduct reservoir operation studies to determine water yield
and power generation based on results of the storable water
analysis for three assumptions as to usage with and without

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