Cowlitz River Project

Since 1963, the Cowlitz River Project has generated clean, renewable electricity while supporting recreation, fish and wildlife, and environmental stewardship throughout southwest Washington.

Located along the Cowlitz River in Lewis County, the project includes Mayfield Dam, Mossyrock Dam, two reservoirs, parks, fish hatcheries and the approximately 14,000-acre Cowlitz Wildlife Area. The project balances renewable energy generation with stewardship of the rivers, lands and natural resources.

At a Glance

• Tacoma Power’s largest hydroelectric project, including Mayfield Dam (1963) and Mossyrock Dam (1968)
• Generates enough renewable electricity to power more than 150,000 Northwest homes annually
• Home to Mayfield Lake and Riffe Lake
• Includes parks, campgrounds, boat launches and day-use areas
• Supports fish, wildlife and environmental stewardship

Stay Informed

Sign up for Cowlitz Currents to receive the latest Riffe Lake Restoration Program updates, project milestones, schedule changes, and other Cowlitz Project news delivered directly to your inbox.

Have questions? Reach out to cowlitz@tacoma.gov.