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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IV. Conclusions and Recommendations

The following conclusions and recommendations are offered from this study and report:

1. The proposed proj ect configuration using an off channel ring dike and re-regulating winter
flows through reservoir storage would provide an effective method of supplementing flows in
the river to offset compact call demands.

2. The geotechnical and engineering data support a conclusion that the construction of the
reservoir using on-site materials for the dam embankment is feasible.

3. There are adequate flows in the South Platte River to support a junior diversion during the
winter months in most years. A review of historic flows in the river showed that the majority
of the years the reservoir would have the ability to fill.

4. The proposed reservoir could be filled by a gravity diversion from the Peterson Ditch.

5. A preliminary opinion of probable cost was prepared for the project. The project could be
constructed at a cost ranging between $600 to $700 per acre-foot. These costs will need to
refined during the preliminary design phase. The cost of wetlands mitigation was not
included in the cost estimates.

6. The project site has wetlands that may be considered jurisdictional by the U.S. Army Corps
of Engineers. An individual 404 permit would need to be obtained to allow for construction
of the project. Preliminary talks with the Corps indicate they would be supportive of the
project because it can have some environmental benefits to the river. A mitigation plan will
probably be required to replace the wetlands destroyed by the project. A wetland delineation
has been done to determine the exact location and extent of wetlands on the site. A regular
monitoring program using the piezometers installed should be started. This data can provide
baseline information on the groundwater table.

7. The proposed project will fall under the scrutiny of the Three States Agreement. A one for
one replacement source of water may be necessary to allow this project to operate during the
study period ofthis agreement. This agreement will playa role in the permitting.

8. There may be other sites in the area of similar nature that could be used for the same
purposes. These alternate sites will probably have the same permitting problems associated
with them as that outlined for the site studied in this report. Jurisdictional wetlands are
difficult to avoid in this reach of the river. This should be considered in the alternative
analysis prepared for a 404 permit application.

9. The monthly modeling ofthe lower river shows that there are sufficient quantities and times
when water in the river may be available for beneficial uses by others in the State.
Additional study is recommended on identifying other participants that may use this project
water for beneficial use in Colorado.

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