Clarks Lake, also known as North Poudre #12 & #13 and Mtn Supply #12, is a privately owned reservoir located in Larimer County, Colorado, near the city of Wellington. This Earth-type dam was completed in 1904 for irrigation purposes, with a height of 26 feet and a storage capacity of 1985 acre-feet. The reservoir covers an area of 250 acres and is fed by the North Fork Poudre river.

Despite its age, Clarks Lake has been well-maintained, with regular inspections and satisfactory condition assessments. The dam has a significant hazard potential, but the risk is considered moderate with appropriate risk management measures in place. The spillway is uncontrolled with a width of 305 feet, and the maximum discharge capacity is 6421 cubic feet per second.

Water resource and climate enthusiasts will find Clarks Lake to be a fascinating example of early 20th-century irrigation infrastructure in Colorado. Its historical significance, engineering design, and ongoing management practices make it a valuable case study for understanding the intersection of water resources and climate resilience in the region.