Silver Lake Flat Dam Rehabilitation Project
The Natural Resources Conservation Service (NRCS) has analyzed alternatives to rehabilitate Silver Lake Flat Dam located on United States Forest Service Uinta-Wasatch-Cache National Forest property. NRCS performed an assessment of Silver Lake Flat Dam in 2004. The 2004 assessment concluded that Silver Lake Flat Dam does not meet current NRCS and Utah State Dam Safety regulations and engineering standards for a Class “C” dam (potential “Loss of Life”). The purpose of this project is to rehabilitate the dam to meet current NRCS and Utah State Dam Safety regulations, current engineering standards, and stabilize the existing dam structures. The life of the dam would be extended for 71 years. The project will also restore the design storage capacity in the reservoir by raising the height of the spillway 2.5 feet, enlarging the spillway to pass the Probably Maximum Flood, provide slope stability for seismic events, and as a result increase the reservoir surface area.
This project is being partially funded by the NRCS Small Watershed Rehabilitation Amendments (PL 106-472) which authorizes funding and technical assistance to rehabilitate aging flood control dams built under the Small Watershed Program (PL83-566). NRCS, as the lead federal agency, completed a NEPA analysis in the form of a Supplemental Watershed Plan and Environmental Assessment (Plan-EA) that analyzed impacts to the natural and human environment from this project. The Environmental Assessment complies with the Council on Environmental Quality’s regulations at 40 CFR Parts 1500-1508 which requires an evaluation of potential environmental impacts associated with federal projects and actions. This project is located within the boundary of the Uinta-Wasatch-Cache National Forest and the United States Forest Service is a cooperating agency.
The Draft Plan-EA public comment period closed on September 25, 2013. NRCS compiled comments received and completed the Final Plan-EA for the project. The NRCS Utah State Conservationist has decided that a Finding of No Significant Impact (FONSI) is approved for the Preferred Alternative (Rehabilitate Dam-Replace Spillway). Construction is anticipated to occur in summer 2015.
According to NRCS NEPA regulations, a 15-day public review period was opened for the project since it is located in a wetland and floodplain. The public review period ended on February 21, 2014 and there were no appeals made against the project.
For further project information please contact:
Greg Allington – McMillen, LLC
1401 Shoreline Dr.
Boise, ID 83702
Norm Evenstad – NRCS
125 S. State Street – Room 4010
Salt Lake City, UT 84138-1100
The documents below require Adobe Acrobat
Finding of No Significant Impact
Silver Lake Flat Dam Finding of No Significant Impact
Silver Lake Flat Dam Final Plan-EA Total Report
Silver Lake Flat Dam Final Plan-EA Report
Silver Lake Flat Dam Final Supplemental Watershed Plan Agreement No. 9
Silver Lake Flat Dam Final Plan-EA Appendix A
Silver Lake Flat Dam Final Plan-EA Appendix B
Silver Lake Flat Dam Final Plan-EA Appendix C
Silver Lake Flat Dam Final Plan-EA Appendix D
Silver Lake Flat Dam Final Plan-EA Appendix E
Silver Lake Flat Dam Rehabilitation Project Draft Plan-EA
Silver Lake Flat Dam Draft Plan EA Meeting Presentation (PDF, 5 MB)
Silver Lake Flat Dam Draft Plan-EA Public Notice (PDF, 115 KB)
Silver Lake Flat Dam Draft Plan-EA Report (PDF, 1.55 MB)
Silver Lake Flat Dam Draft Plan-EA Appendix A (PDF, 678 KB)
Silver Lake Flat Dam Draft Plan-EA Appendix B (PDF, 3.26 MB)
Silver Lake Flat Dam Draft Plan-EA Appendix C (PDF, 2.46 MB)
Silver Lake Flat Dam Draft Plan-EA Appendix D (PDF, 1.49 MB)
Silver Lake Flat Dam Draft Plan-EA Appendix E (PDF, 29.8 MB)
Updated: March 21, 2014