The Redwood Landfill Leachate Impoundment, located in Marin, California, is a privately owned structure designed for flood risk reduction and tailings storage. Completed in 1991, this earth dam stands at a height of 10 feet with a hydraulic height of 8 feet and a length of 1800 feet. It has a storage capacity of 84.3 acre-feet and covers a surface area of 9 acres. Despite being regulated, permitted, and inspected by the state, the dam is classified as having a significant hazard potential, with its condition assessed as fair during the last inspection in September 2017.

This offstream impoundment is part of the Sacramento District and falls under the jurisdiction of the Department of Water Resources and Safety of Dams in California. The primary purpose of the Redwood Landfill Leachate Impoundment is to manage tailings and reduce flood risks in the area. While the dam has not undergone any significant modifications since its completion, its hazard potential highlights the importance of ongoing monitoring and risk management measures to ensure the safety and integrity of this vital water resource infrastructure. For water resource and climate enthusiasts, the Redwood Landfill Leachate Impoundment serves as a key example of the intersection between waste management, water conservation, and environmental stewardship.