Gypsum Wash Dam Rehabilitation

Project Description

The Natural Resources Conservation Service (NRCS) is analyzing alternatives to rehabilitate Gypsum Wash Dam which is located near the foothills on the southeast side of Washington City, Utah.  NRCS performed an assessment of Gypsum Wash Dam in 2006.  The 2006 assessment concluded that the Gypsum Wash 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 a minimum of 50 years and a maximum of 100 years.  The project would also restore the design storage capacity in the reservoir by possibly raising the height of the dam, removing sediment, enlarging the spillway to pass the Probable Maximum Flood, provide slope stability for seismic events, and as a result potentially increase the reservoir surface area.

NEPA Analysis

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, is initiating NEPA analysis in the form of a Supplemental Watershed Plan and Environmental Assessment to analyze impacts to the natural and human environment from this project.  The Environmental Assessment will comply with the Council on Environmental Quality’s regulations at 40 CFR Parts 1500-1508 which require an evaluation of potential environmental impacts associated with federal projects and actions.  The project sponsor is the Washington County Flood Control Authority.

Current Status

The project is currently in the Draft Supplemental Watershed Plan and Environmental Assessment phase and NRCS is developing project alternatives and performing a draft environmental analysis on these alternatives.

Contact Information

For further project information please contact:

Greg Allington – McMillen, LLC
1401 Shoreline Drive
Boise, ID  83702
208.342.4214 phone
208.342.4216 fax


Norm Evenstad – NRCS
125 S. State Street – Room 4010
Salt Lake City, UT 84138-1100

Project Documents

Utah Division of Water Rights Dam Safety – Gypsum Wash Dam Website


Scoping Report (PDF, 1.58 MB)
Scoping Notice
(PDF, 344 KB)
Scoping Project (PDF, 202 KB)
Scoping Public Meeting Presentation (PDF, 202 KB)

NOTE: We will add other directories as we move through the NEPA process

Updated: April 3, 2014