Upper Oso, located in Mission Viejo, Orange County, California, is a key water resource infrastructure managed by a public utility. This earth dam, completed in 1979, stands tall at 142 feet, with a hydraulic height of 135 feet, serving multiple purposes including flood risk reduction, irrigation, and water supply. With a storage capacity of 3,700 acre-feet and a drainage area of 1.13 square miles, Upper Oso plays a crucial role in managing water resources in the region.

The dam, situated on Oso Creek, is under the regulatory oversight of the California Department of Water Resources for safety and inspection. Despite its satisfactory condition assessment, Upper Oso poses a high hazard potential, necessitating regular inspections and emergency preparedness measures. In the event of any emergencies, the dam operators are required to follow established protocols for ensuring public safety and mitigating risks associated with its operation.

As a vital component of the water supply infrastructure in the area, Upper Oso underscores the importance of sustainable water management practices in the face of changing climate patterns. With a focus on ensuring the dam's integrity and functionality, stakeholders continue to monitor its performance and implement necessary risk management measures to safeguard against potential hazards and support the water needs of the local community.