The Tolt River - South Fork dam, also known as Tolt Main Dam, is a key structure owned by the local government in King County, Washington. Completed in 1962, this earth dam stands at a height of 200 feet and serves primarily for water supply purposes. With a maximum storage capacity of 68,400 acre-feet and a normal storage of 57,500 acre-feet, the dam plays a crucial role in ensuring reliable water supply to the surrounding area.

Located in Carnation, Washington, the Tolt River - South Fork dam is regulated by the Federal Energy Regulatory Commission and has a high hazard potential due to its size and location. The dam's spillway, which is uncontrolled and 40 feet wide, helps manage excess water flow during peak discharge events. The dam's inspection frequency is set at 1 year, with the last inspection conducted in September 2020. Although the current condition assessment is not available, the emergency action plan was last revised in January 2021.

Water resource and climate enthusiasts will appreciate the Tolt River - South Fork dam for its critical role in water supply management and its impact on the surrounding ecosystem. As a key structure in the region, the dam's risk assessment is moderate, highlighting the need for ongoing monitoring and management measures to ensure its safety and reliability. The dam's association with the Federal Energy Regulatory Commission underscores its importance in the broader context of energy and water resource regulatory frameworks.