Located in Boulder, Colorado, the Foothills dam stands as a testament to early 20th-century engineering, with construction completed in 1911 for the primary purpose of irrigation. This private-owned structure, designed by R.E. Richardson, Rocky Mountain Consultants, and Smith Geotechnical, boasts an earth dam type with a core made of stone and foundations in rock and soil. Standing at a height of 52 feet and a length of 3150 feet, Foothills reservoir has a normal storage capacity of 4139 acre-feet and serves as a vital water resource along the St. Vrain Creek-TR.

Over the years, Foothills has undergone multiple modifications to enhance its structural and hydraulic integrity, with significant upgrades in 1987, 2001, and 2001. The dam's spillway, with a width of 222 feet, is uncontrolled, while its hazard potential is classified as high, though its condition assessment remains satisfactory. With a risk assessment rating of moderate, Foothills continues to be closely monitored through regular state inspections and enforcement to ensure its safety and functionality for the surrounding community in Longmont and beyond.