Monument #1, located in Mesa County, Colorado, is a privately owned earth dam that was completed in 1960 for the primary purpose of irrigation along the Monument Creek. Designed by F.C. Merriell, this dam stands at a height of 32 feet with a hydraulic height of 35 feet and a length of 500 feet. It has a storage capacity of 760 acre-feet, with a normal storage level of 572 acre-feet and a surface area of 40 acres.

The dam is regulated by the Colorado Department of Water Resources (DWR) and undergoes regular inspections, with the last assessment in August 2020 rating its condition as fair. With a significant hazard potential and a moderate risk assessment, measures are in place to manage any potential emergencies. The spillway, an uncontrolled type, has a width of 60 feet, and the dam features a slide gate outlet for water release.

Monument #1 plays a crucial role in providing water for irrigation in the region, serving as a vital resource for agriculture. With its sturdy construction and state-regulated oversight, this dam stands as a testament to sustainable water management practices in Colorado, ensuring the continued availability of water for the surrounding area.