Mountain Lake, also known as Diamond Lake or Evans Gulch No. 2, is a privately owned water resource located in Lake County, Colorado. Built in 1889, this Earth type dam stands at a height of 22 feet and serves primarily as a water supply source, with a storage capacity of 150 acre-feet. The dam's spillway, with a width of 30 feet, is uncontrolled, and it has a significant hazard potential but is currently in satisfactory condition.

Situated in the picturesque city of Leadville, Mountain Lake is regulated by the Colorado Department of Water Resources, with state permitting, inspection, and enforcement in place to ensure its safety and compliance. The dam overlooks the Evans Gulch-TR river or stream, with a drainage area of 0 and a maximum discharge capacity of 630 cubic feet per second. Despite its moderate risk assessment rating of 3, the dam has undergone regular inspections, with the last one being conducted in September 2019.

Water resource and climate enthusiasts will find Mountain Lake a fascinating example of historic dam engineering in Colorado. With its long history and critical role in providing water supply, this dam stands as a testament to the importance of maintaining and managing our water resources effectively in the face of changing environmental conditions. Mountain Lake's unique characteristics and regulatory oversight make it a valuable asset in understanding the intersection of water management, infrastructure, and environmental conservation in the region.