About the Project

Nelson Dam was an eight-foot-high concrete barrier built in the 1920s and rebuilt in the 1980s to divert water for agricultural and residential use in and near Yakima, Washington. Until 2022, the dam crossed the Naches River, the largest tributary of the Yakima River where the Yakama Nation holds treaty rights to fish for cultural, spiritual, and economic reasons. Work to restore habitat and build new infrastructure continues for several years. Downstream of Yakima on Cowiche Creek, two more diversions—Old Union and Fruitvale—block fish passage and exacerbate flood hazards. Together, these three dams have dramatically altered the river’s hydrology, slowing the flow upstream, warming the water, and preventing salmon and steelhead from accessing hundreds of miles of habitat. Behind the dams, rock, gravel, and sediment have settled, starving the floodplain of sediment and increasing public safety risk due to flooding.

The City and County of Yakima are removing removing Fruitvale and Old Union dams and replacing Nelson Dam with a roughened channel that will replicate more natural river conditions and give fish access to 309 miles of some of the best cold-water habitat in the Yakima Basin to build long-term climate change resilience. By combining multiple water diversions into one, the project will reduce long-term maintenance costs, improve fish passage, fulfill Tribal treaty rights, expand the floodplain, and improve public safety. This builds on prior work by the City and County of Yakima to update water infrastructure, remove levees, restore floodplains, and reduce flood risk and hazard.

The project is part of the Yakima Basin Integrated Plan, a widely praised ecosystem restoration and climate adaptation collaboration of irrigators, environmentalists, government agencies, and the Yakama Nation.