Happy Valley, also known as Simnasho Reservoir, is a federal-owned water resource located in Wasco, Oregon. Managed by the Bureau of Indian Affairs, this reservoir primarily serves the purpose of irrigation, with additional recreational uses. Constructed in 1938, it has a structural height of 45 feet and a storage capacity of 490 acre-feet, making it a vital water source for the surrounding area.

Situated along Quartz Creek, Happy Valley plays a crucial role in water management and provides essential irrigation support for the region. With a maximum discharge of 225 cubic feet per second and a high hazard potential, this reservoir requires regular inspections and monitoring to ensure its safety and functionality. Despite its age, the dam remains in good condition, meeting regulatory guidelines and serving as a key asset for water supply and agricultural needs in the area.

The risk assessment for Happy Valley indicates a very high risk level, emphasizing the importance of effective risk management measures and emergency preparedness. With the involvement of the Bureau of Indian Affairs in its operation, maintenance, and regulation, this reservoir continues to be a significant water resource for the local community, highlighting the intersection of water resource management, climate resilience, and safety in the face of potential hazards.