Union Valley is a captivating hydroelectric and recreational dam located in El Dorado, California. Built in 1962 by Bechtel, this Earth-type dam stands at an impressive height of 440 feet and has a storage capacity of 266,369 acre-feet, with a normal storage level of 204,000 acre-feet. The dam is situated on the Big Silver Creek and covers a surface area of 2,860 acres, providing a picturesque backdrop for outdoor enthusiasts and climate aficionados alike.

Managed by the Federal Energy Regulatory Commission, Union Valley serves as a vital water resource in California, with a maximum discharge capacity of 44,500 cubic feet per second. The dam features a controlled spillway with a width of 85 feet and two Tainter radial gates for water regulation. Despite its high hazard potential, the dam is regularly inspected and regulated by both state and federal agencies to ensure public safety and environmental protection. With its scenic location and impressive engineering, Union Valley offers a unique blend of hydroelectric power generation and recreational opportunities for visitors to enjoy.

With its rich history and strategic location in the Coloma area, Union Valley continues to play a crucial role in California's water resource management efforts. The dam's risk assessment indicates a very high level of risk, emphasizing the importance of ongoing monitoring and maintenance to safeguard its structural integrity. As a popular destination for outdoor activities and nature enthusiasts, Union Valley stands as a symbol of sustainable water utilization and climate resilience in the region, highlighting the intersection of engineering ingenuity and environmental stewardship in the face of changing climate patterns.