In Wyoming’s Sweetwater County, the Joint Powers Water Board manages the treatment and supply of drinking water, all of which is drawn from the Green River. Although the river generally provides enough water for county residents, its quality drops when spring runoff or heavy rainfall washes soil and debris into the river. Historically, during those periods the Green River water treatment plant sometimes had difficulty meeting demand.
In response, the board decided to build a dam and levee to create an off-channel reservoir that would hold additional river water and allow suspended solids to settle out of it before treatment. The solution would also provide an emergency water source if contaminants or other harmful substances were found in the river.
Construction was nearly complete when a leak test revealed that almost five times more water than expected—hundreds of gallons a minute—was seeping into the earth. In addition, the levee was slowly sinking into the ground, and the soil-cement reservoir lining was rapidly deteriorating. The board solicited bids for a team to design and implement repairs and finish the storage project.
Barr and our project partners, Freese and Nichols and JFC Engineers and Surveyors, were selected for the work. After inspecting the reservoir lining, dam, and levee, our team developed a remediation plan that included adding a concrete leveling surface to the soil-cement steps on the dam face, building an internal earthen buttress to stabilize the levee, and installing a membrane liner to minimize leakage.
The Barr team completed investigation and design and helped procure a contractor in less than a year, and construction was deemed substantially complete in spring 2022. Sweetwater County now has a reliable alternative water source when the Green River runs muddy.