Cowan Lake Dam Replacement Project

WSA is excited to begin the replacement of Cowan Lake Dam in summer 2026, a project that will enhance safety and reliability for the region.  

The project involves replacing the current dam with a modern structure featuring earth embankments and a four-bay concrete radial-gate system. This new control structure, along with the earthen dam, will be built just upstream of the existing facility.  

Construction is expected to take approximately two years, with the new dam ready for service ahead of the 2028 spring runoff. 

The new dam will have gates to control large water flows, a small outlet to augment the natural-style fishway so fish can move freely past the dam. Safety features like floating barriers, fences, and clear signs will also be added. The way the lake is managed—its water levels and outflows—will stay the same as before. 

The Cowan Lake Dam recreation site will be closed during construction to keep everyone safe. The closure will run from summer 2026 to spring 2028. This includes the boat launch. Signs will be posted at the entrance, boat launch, and near the work areas to let visitors know about the closure. 

The project will be supported by an engineered earthen cofferdam and a gated bypass channel, ensuring Cowan Lake remains at its current Full Supply Level (FSL) throughout construction and minimize disruption during the process. 

WSA hosted a public information session on February 6, 2026, to update residents and stakeholders about the project and upcoming work, potential impacts for area residents, and operational plans during construction.