Rancho Del Ciervo, also known as Dennis Reservoir, is a privately owned earth dam located in Santa Barbara, California. Built in 1938, this dam serves primarily as a water supply for irrigation and domestic use. With a height of 65 feet and a storage capacity of 165 acre-feet, Rancho Del Ciervo plays a crucial role in water resource management in the region.

Managed by the California Department of Water Resources (DWR) under the Safety of Dams program, Rancho Del Ciervo is regularly inspected to ensure its structural integrity and compliance with state regulations. Despite being classified as having a high hazard potential, the dam's condition was assessed as satisfactory during its last inspection in May 2020. With a drainage area of 0.76 square miles, this reservoir provides vital water resources for the surrounding Tehon Ranch area.

As a key component of the local water infrastructure, Rancho Del Ciervo represents the intersection of water resource management and climate resilience efforts in California. Its strategic location along Tr San Jose Creek and its role in supplying water for irrigation highlight the importance of maintaining and monitoring this dam to ensure the safety and sustainability of water resources in the region.