Harry Denning Irrigation #3, located in Weld County, Colorado, is a vital water resource infrastructure designed by USDA NRCS for private irrigation purposes. Completed in 1962, this Earth dam stands at 27 feet high with a length of 1680 feet, providing a storage capacity of 50 acre-feet. The dam is situated on the Lost Creek-TR river/stream and is regulated by the Colorado Department of Water Resources.

With a low hazard potential and fair condition assessment as of 2010, Harry Denning Irrigation #3 serves as a crucial component of the local water management system in Keenesburg. The dam's uncontrolled spillway, with a width of 25 feet, allows for a maximum discharge of 310 cubic feet per second. Although the risk assessment indicates a moderate level of risk, the dam is inspected every 6 years to ensure its structural integrity and safety for the surrounding community.

Overall, Harry Denning Irrigation #3 plays a significant role in sustaining agricultural activities in the region by providing reliable water storage and distribution for irrigation purposes. As a key piece of infrastructure in the Omaha District, this dam showcases the importance of proper design, maintenance, and regulation in managing water resources effectively amidst changing climate conditions.