Located in Rancho Santa Fe, California, the San Dieguito Reservoir is a vital water resource with a primary purpose of hydroelectric power generation. Completed in 1918, this multi-arch dam stands at a height of 51 feet and has a storage capacity of 883 acre-feet, serving multiple purposes including irrigation and water supply. The reservoir spans 56 acres with a drainage area of 1.4 square miles, drawing water from the Tr Escondido Creek.

Managed by a public utility, the dam is regulated by the California Department of Water Resources (DWR) to ensure safety and compliance with state regulations. Despite its high hazard potential, the dam's condition assessment in 2017 deemed it satisfactory, with regular inspections and emergency action plans in place. With a history dating back over a century, San Dieguito Reservoir remains a critical infrastructure for water management in San Diego County, contributing to the region's water supply and hydroelectric power needs.