Lake Orinda, also known as Lake Cascade, is a privately owned water supply reservoir located in Orinda, California. Built in 1935, this earth dam stands at a height of 45 feet and has a hydraulic height of 35.6 feet. With a storage capacity of 111.2 acre-feet and a surface area of 9.5 acres, this reservoir serves primarily for irrigation and water supply purposes.

Cascade Creek feeds into Lake Orinda, which has a drainage area of 0.48 square miles. The dam has a high hazard potential, but its condition is assessed as satisfactory. Regular inspections are conducted by the California Department of Water Resources to ensure its safety. With a maximum discharge of 474.1 cubic feet per second, Lake Orinda plays a crucial role in supplying water to the surrounding area.

Despite its small size, Lake Orinda is a vital water resource in Contra Costa County. Managed by private entities, the reservoir is subject to state regulations and inspections to ensure its functionality and safety. With its rich history and important role in supporting the local ecosystem, Lake Orinda is a significant asset in the region's water infrastructure.