Ish #3 (Main Dam) located in Larimer, Colorado, along the Big Thompson River, stands as a historic irrigation structure completed in 1905. This private earth dam boasts a height of 42 feet and a storage capacity of 9065 acre-feet, primarily serving agricultural purposes in the region. With a surface area of 314 acres and a maximum discharge of 3066 cubic feet per second, this dam plays a crucial role in water resource management in the area.

Despite its age, Ish #3 maintains a satisfactory condition assessment and a high hazard potential, highlighting the importance of regular inspections and maintenance. The dam features an uncontrolled spillway with a width of 60 feet and a moderate risk assessment rating of 3. The regulatory oversight from the Colorado Department of Water Resources ensures that the dam meets state permitting, inspection, and enforcement requirements, underscoring the commitment to safety and compliance in its operation.

As climate change continues to impact water resources, Ish #3 serves as a vital infrastructure for managing water supply and irrigation needs in the region. With its rich history and critical role in water management, this dam stands as a testament to the engineering ingenuity of the past while facing the challenges of the present and future in maintaining water security and resilience in the face of changing climate conditions.