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• <br />IV. Conclusion and Recommendations <br />The following conclusions and recommendations are offered from this study and report: <br />1. The proposed project configuration using an off channel ring dike and re- regulating winter flows <br />through reservoir storage would provide an effective method of supplementing flows in the river <br />to offset compact call demands. <br />2. The geotechnical and engineering data support a conclusion that the construction of the reservoir <br />using on -site materials for the dam embankment is feasible. <br />3. There are adequate flows in the South Platte River to support a junior diversion during the winter <br />months in most years. A review of historic flows in the river showed that 2,200 acre -feet could <br />be diverted in all but two years for the past 30 years of record depending on the diversion <br />assumptions used. <br />4. If the reservoir is operated under a fill and refill scenario, it can effectively re- regulate 2,400 <br />acre -feet on a long term average. This configuration requires increased sizing of inlet and outlet <br />structures to allow rapid response to the gage flow at the state line. <br />5. The proposed project would be best configured as a standard diversion reservoir with controlled <br />releases. Recharge from this site would provide reduced benefits. However, a recharge site <br />might be configured as a part of wetlands mitigation. <br />6. Approximately % of the proposed reservoir could be filled by a gravity diversion from the <br />Peterson Ditch. A pumping system either from the GASP wells or from a low head pump station <br />located on the Peterson Ditch would be necessary to top off the reservoir. <br />7. A preliminary opinion of probable cost was prepared for the project. The project could be <br />constructed at a cost ranging between $750 to $800 per acre -foot. These costs will need to <br />refined during the preliminary design phase. <br />8. The project site has wetlands located on it considered jurisdictional by the U.S. Army Corps of <br />Engineers. An individual 404 permit would need to be obtained to allow for construction of the <br />project. Preliminary talks with the Corps indicate they would be supportive of the project <br />because it can have some environmental benefits to the river. A mitigation plan will probably be <br />required to replace the wetlands destroyed by the project. A wetland delineation should be done <br />as the next step in determining the exact location and extent of wetlands on the site. A regular <br />monitoring program using the 6 piezometers installed should be started. This data can provide <br />baseline information on the groundwater table. <br />9. The proposed project could effectively supplement flows in the river at the stateline. The number <br />of days that the compact flow of 120 cfs could be held would range from 24 to 37 days based on <br />historic records and the assumptions used in calculations. This estimate is based on operating the <br />reservoir releases under idealized conditions and augmenting flows in the river only when they <br />are above 70 cfs. Actual operating conditions may reduce the number of days. <br />21 <br />