Mossyrock, located in Toledo, Washington, is a public utility owned hydroelectric dam on the Cowlitz River. Completed in 1968, this arch dam stands at 606 feet tall and has a storage capacity of 1.9 million acre-feet. With a primary purpose of generating hydroelectric power, the dam also serves flood risk reduction and recreation purposes.

Managed by the Federal Energy Regulatory Commission, Mossyrock is considered a high hazard potential dam with a very high risk assessment rating. The dam features a controlled spillway with a width of 170 feet and is equipped with four Tainter radial gates for regulating water flow. Despite its age, the condition assessment of Mossyrock is not available, highlighting the need for further inspection and maintenance to ensure its safety and functionality.

As a key structure in the region, Mossyrock plays a vital role in water resource management and climate resilience efforts. With its strategic location and impressive engineering, the dam stands as a testament to the importance of sustainable water infrastructure in the face of changing environmental conditions.