Zosel Dam
Current conditions
As of November 22 , the Osoyoos Lake level has been steadily dropping over the past few months to as we have been releasing water downstream to meet instream flow minimums. The minimum instream flows were reduced on November 15th. We expect to be able to maintain the current lake elevation (about 910 feet) and meet the minimum instream flows for the remainder of 2024 and until the spring freshet of 2025. We will continue to strive to keep lake levels within the International Joint Commission (IJC) mandated rule curve and meet the demands of instream flows.
You can track lake levels in real time, and find other information about the project by visiting the USGS web page for Osoyoos Lake.
Zosel Dam near Oroville, Washington. Photo by Chad Mathews
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.
The project is proposed to improve Zosel dam and its functionality. Improvements include replacement of spillway gates, new lifting mechanisms, an additional heated gate, a new backup generator, refurbishment of existing stop logs and stop log hoists, and electrical upgrades. The new lifting mechanisms use a cable and drum system to lift the gates faster than the current system. The heated gate will be used during colder months when ice can impact operations. Electrical upgrades include updating the lighting systems, addressing fall hazards, and replacing the backup generator.
Additionally, a 12-foot wide, 9-inch depth gravel access road will be built for dam improvements and maintenance. The dam will remain operational during construction to maintain the Osoyoos Lake elevations.
Construction of Zosel dam was completed in 1987. The purpose of the Lake Osoyoos International Water Control Structure (Zosel Dam) is to maintain Osoyoos Lake water levels, as determined by the International Joint Commission (IJC). The IJC consists 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 international border.
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
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.
History
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.
Related links
Contact information
Samantha Long, EIT
Dam Safety Office Manager
samantha.long@ecy.wa.gov
Office: 360-407-6603
Cell: 360-972-4426