Zosel Dam

comment icon

Zosel Dam Repair Latest News!

Current status: Construction Documentation Phase.

Lake Osoyoos levels will be higher than normal, anticipating lower spring runoff due to lower-than-normal snowpacks. Read more

Zosel dam was completed in 1987 to maintain Osoyoos Lake water levels, as determined by the International Joint Commission, a board made up of representatives from the U.S. and Canada. The lake is surrounded by summer homes and provides recreational opportunities and irrigation water on both sides of the Canadian and United States borders. Zosel Dam is a critical piece of state infrastructure, which we own and operate by under the authority of RCW 43.21A.450.

Read about the history of the Zosel Dam.

Water behind Zosel Dam. with grass in the foreground and snow-capped hills in the background.

Zosel Dam near Oroville, Washington. Photo by Chad Mathews

Current Conditions

As of April 9, the Osoyoos Lake elevation is 911.81 feet (277.92 meters) and is at the historical maximum for the 1987-2023 period of record for this time of year. Lake levels have remained within the International Joint Commission (IJC) mandated rule curve in 2024 and the Zosel Dam owner/operator (Washington State Department of Ecology) has remained in compliance with the IJC orders. Find this information, and more, here.

You can track lake levels in real time, and find other information about the project by visiting the USGS web page for Osoyoos Lake.

2023-25 Biennium Capital Project

In 2020, we contracted an engineering assessment to determine the current state of the sluice gates, structure, and other elements of the dam. To eliminate deficiencies in the structure, this assessment recommended several projects at the facility.

Based on the completed assessment, the following identified repair and maintenance projects for Zosel Dam are:

  • Professional services & contingency – Includes engineering services to do the installation and a contingency for any unexpected issues with design and installation.
  • Gates, hoists, & control systems – Install a new drum hoisting system, gate controls, electrical systems, video surveillance, and refurbish spillway gates. Certify operation and installation. 
  • Electrical system updates – Update lighting systems, address fall hazards, replace the generator, and provide updated operations and maintenance manuals (including training) for the newly renovated facility components. 

Ecology requested $5,549,000 for needed repair of Zosel Dam in Okanogan County to ensure proper operation and long-term care and protection of this state-owned asset. The budget for this project was developed based on an engineering assessment and budget estimate, dated December 22, 2020.

The budget of $5.5 million was approved and a deadline of 2025 was set to finish the project. Costs include the required consultant, project management, and contingency funds calculated, and the associated agency staff costs to provide project oversight and management, technical assistance, and stakeholder coordination for the project.

This project will be broken down into four phases:

  • Phase one: Design of repairs and upgrades
  • Phase two: Approval of designs. All entities involved in the project will approve (International Joint Commission, Department of Ecology, Department of Enterprise Services, etc.)
  • Phase three: Final, approved designs will be used for the contractual bidding process
  • Final phase: Construction of the project