Spencer Dam, located in Grangeville, Idaho, is a privately owned structure regulated by the Idaho Department of Water Resources for irrigation purposes. The dam is situated on an unnamed stream and Threemile Creek and was completed in 1954. With a height of 15.4 feet and a storage capacity of 25 acre-feet, the dam serves as a significant asset for water resource management in the area.

Despite its age, Spencer Dam is rated in fair condition with a significant hazard potential, prompting regular inspections every four years to ensure its structural integrity. The dam features an uncontrolled spillway and no outlet gates, making it crucial for proper maintenance and risk management measures. The risk assessment for Spencer Dam is moderate, highlighting the importance of proactive strategies to address any potential issues and ensure the safety of the surrounding community.

Managed by a private entity, Spencer Dam plays a vital role in supporting irrigation activities in the region. With its stone core and earth dam type, the structure represents a blend of traditional engineering practices and modern regulatory standards enforced by the state. As water resource and climate enthusiasts, monitoring and maintaining Spencer Dam is essential to safeguarding its operational efficiency and minimizing the risk of any potential hazards in the future.