Mcmullen, a privately-owned dam located in Hollister, Idaho, plays a crucial role in irrigation by harnessing the waters of Cottonwood Creek and Rock Creek. Completed in 1948, this earth dam stands at a height of 25.4 meters and has a normal storage capacity of 350 acre-feet, serving an area of 45 acres. With a significant hazard potential and a fair condition assessment, Mcmullen is subject to regular inspections by the Idaho Department of Water Resources to ensure its safety and integrity.

The dam features a controlled spillway with a width of 111 feet and a maximum discharge capacity of 370 cubic feet per second. Despite its age, Mcmullen has been maintained to meet state regulations and undergoes inspections every four years. The risk assessment for this dam is classified as very high, emphasizing the importance of risk management measures to mitigate potential hazards and ensure the safety of downstream communities and infrastructure.

Located in Twin Falls County, Mcmullen's strategic position and function in irrigation highlight its significance in water resource management in the region. With its historical legacy and ongoing maintenance efforts, this dam serves as a critical infrastructure asset for agricultural activities in the area, demonstrating the intersection of water resource management and climate resilience in Idaho's landscape.