PROJ02106

• Contract/PO #: FS0063FX
• Contractor Name: Groundwater Appropriators of the South Platte
• Contract Type: Miscellaneous
• Water District: 0
• Loan Projects - Doc Type: Feasibility Study

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The primary purpose of the proposed reservoir will be to augment flows in the South Platte River
at times when the flow decreases below the compact entitlement and out-of-priority replacements
are required of GASP. Table 1 and Table 2 are a summary of the operating scenarios for the
3,900 acre-foot and 5,400 acre-foot reservoirs. The modeling calculated the out-of-priority
depletions at the state line due to GASP member's diversions. The modeling demonstrated that
the 3,900 acre-foot reservoir would meet all required replacements with the exception of one
year, with the 5,400 acre-foot reservoir meeting all the replacement demands. In the majority of
the years, both the 3,900 acre-foot and 5,400 acre-foot reservoirs are capable of meeting all
required replacements with storage volume available for other uses.

H. Floodplain Issues
The proposed reservoir location is approximately ~ mile north of the South Platte River. Further
evaluation will be necessary to determine the exact location of Floodplain. It is anticipated based
on the location of State Highway 138 and the Union Pacific railroad grade, that the South Platte
floodplain will not affect this site.

The design of a reservoir at this location will require consideration of local drainage concerns to
protect surrounding property owners. The proposed ring dike will require routing of local
drainage around the reservoir. The rehabilitation of the Sedgwick Sand Draw project flood
channel is one of the aspects of considering the local drainage issues.

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