Nelson Dam project as of May 16, 2022. Photo courtesy Yakima County

Work continues on the Nelson Dam removal and replacement project and will result in temporary road closures.

Work includes pouring concrete for a new fish screen structure. The work requires temporary closure of South Naches Road at Powerhouse Road. This closure will start at 6:00 am and end by 5:00 pm on the following dates:

  • Thursday, May 19th
  • Tuesday, May 24th
  • Thursday, May 26th

As always, the schedule for this type of project is subject to change daily dependent on weather, equipment failure, and emergencies.

An update on the Nelson Dam removal project notes that approximately 80 percent of the existing dam has been removed as of February 28th. The 5-page project status briefing was published on Wednesday, March 16th. Click the following for a copy of the report:

Future work over the next month will include installing a temporary bridge to get equipment, material and personnel in and out of the de-watered area, as well as a cofferdam for heavy equipment access and continued de-watering of the work area.

Work on the Nelson Dam removal and replacement project began in August 2021. The project will improve fish passage and sediment continuity to improve habitat, increase flow conveyance to decrease flooding risks for nearby landowners, and improve water supply reliability.

Nelson Dam, on the Naches tributary of the Yakima River, was built in the 1920s to divert irrigation water for Yakima and the Naches-Cowiche Irrigation Association. The original design did not allow any fish passage. The dam has held back tons of sediment and silt over the years, raising the river bed and causing the Naches River to overflow its banks and move into the surrounding community during even minor flooding.

The Washington Dept. of Fish and Wildlife detailed how fish are being saved even as water levels are lowered to allow workers to carry out the project.

The City of Yakima and Yakima County have been collaborating on the design and implementation of this project. The dam removal and replacement is one of several major public works projects initiated by the Yakima Basin Integrated Plan.

The City of Yakima is investing $10.8 million in the $26 million multi-agency collaboration — part of the Yakima Basin Integrated Plan — over the next four to five years.

The City of Yakima received $4.4 million from the Washington State Floodplain by Design program, about $4.1 million from Brian Abbott Fish Barrier Removal Board, and just over $1.3 million from the state’s Capital Budget for the Nelson Dam project. The City continues to seek additional funding from state and federal sources to complete the project.

For more about the project, contact City of Yakima Assistant Public Works Director Dave Brown by phone at 509-575-6154 or by email at David.Brown@yakimawa.gov

Project photos from Summer 2021 available at Nelson Dam Project Progress | Snapshots (yakimawa.gov)