Lower Chinns is a private-owned earth dam located in Idaho Springs, Colorado, along the Fall River. Built in 1934, this dam serves primarily for irrigation purposes, but also supports recreation and water supply activities. Standing at a height of 18 feet with a hydraulic height of 13 feet, Lower Chinns has a storage capacity of 170 acre-feet and covers a surface area of 12 acres.

Despite its age, Lower Chinns is in satisfactory condition according to a recent assessment in July 2020, with a high hazard potential due to its location and design. The dam has a spillway width of 37 feet and a maximum discharge capacity of 560 cubic feet per second. While the risk assessment deems it moderate, appropriate risk management measures are in place to ensure the safety of the surrounding areas in case of emergencies. Managed by the Colorado Department of Water Resources, Lower Chinns plays a crucial role in the water resource management of Clear Creek County, demonstrating the intersection of infrastructure, climate resilience, and environmental stewardship.