C153705 Feasibility Study

• Contract/PO #: C153705
• Contractor Name: Beaver Reservoir Company
• Contract Type: Loan
• Water District: 59
• County: Gunnison
• Bill Number: SB 94-029
• Loan Projects - Doc Type: Feasibility Study

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Alternative 5: Partial Reservoir Seepage Blanket

This alternative would cover an area of approximately 184,000 square feet upstream of
the reservoir with a man-made liner and filter medium covered with native soils. The
reservoir would be excavated to achieve a typical grade of 3:1 (horizontal to vertical) or
flatter. The reservoir would then be lined with a geosynthetic clay liner (GeL), covered
with native soils. This alternative would have the effect of reducing the migration of
fines downstream through the foundation, thereby reducing the sinkhole potential.

7.3 ALTERNATIVE EVALUATION CRITERIA

This section presents a discussion of the evaluation criteria. Each of the alternatives
presented above is designed to improve the existing condition of Beaver Reservoir.

7.3.1 Project Output

With the exception of the breaching alternati~i, the alternatives are not designed to
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increase or decrease the project output. Therefore, project output was not used as an
evaluation criterion.

7.3.2 Operation and. Maintenance"..

With the exception of~thebreaching alternative, the alternatives are not designed to
change the operations-a!ldmaintenance (O&M) of the dam. Therefore, project O&M
was not used as an-evaluation criterion.

7.3.3 Project,Impacts

With the exception of the breaching alternative, the proposed alternatives are not
expected to have a significant impact on the natural, or the manmade environment, or
the local social structure. Each of the alternatives will require draining the reservoir, but
the reservoir is drained annually and, therefore, should not significantly affect local fish
populations. Therefore, project impact was generally not a consideration.

23067/Rl.7 09-03-93(IO:lSam)/RPT

7-3

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