Keystone, also known as South Twin Lake, is a privately owned irrigation dam located in Carbon County, Wyoming. Built in 1921 on South Brush Creek, this earth dam stands at 10 feet tall with a hydraulic height of 7 feet. With a storage capacity of 343 acre-feet and a normal storage capacity of 172 acre-feet, Keystone serves as a crucial water resource for the surrounding area.

Despite its low hazard potential and fair condition assessment, Keystone is regulated by the State of Wyoming and undergoes regular inspections, permitting, and enforcement to ensure its safety and functionality. The dam features an uncontrolled spillway with a width of 3 feet and an outlet gate for water release. With a risk assessment rating of moderate, Keystone plays a vital role in managing water resources for irrigation in the region.

As a key component of the water infrastructure in Saratoga, Wyoming, Keystone illustrates the importance of proper dam management and maintenance in the face of changing climate conditions. Its history, design, and purpose highlight the intersection of water resource management, climate resilience, and the need for sustainable practices to ensure the continued availability of water for irrigation in the area.