Richardson, also known as Hedgpeth Lake, is a privately owned dam located in Sonoma, California. Built in 1954, this earth dam stands at a height of 65 feet and serves primarily for water supply purposes, including irrigation. The dam has a storage capacity of 520 acre-feet and covers a surface area of 22 acres, with a drainage area of 0.5 square miles.

Managed by the California Department of Water Resources (DWR) under the Safety of Dams program, Richardson is regulated, permitted, inspected, and enforced by the state to ensure its structural integrity and safe operation. With a significant hazard potential, the dam has been assessed as satisfactory in condition as of September 2017. It is located in Soda Springs near an unnamed tributary to Pepperwood Creek, under the jurisdiction of the San Francisco District of the US Army Corps of Engineers.

Water resource and climate enthusiasts will be intrigued by the detailed information available about Richardson, from its design and construction by the Natural Resources Conservation Service to its emergency action plan and risk management measures. This dam serves as a crucial resource for water supply in the region, highlighting the intersection of infrastructure, regulation, and environmental stewardship in sustaining vital resources for communities in California.