Mallard #1 is a Federal-owned earth dam located in Johnson, Wyoming, along the Sackett Draw. Completed in 1999, this dam serves multiple purposes including fire protection, stock, and small fish pond. With a height of 23 feet and a length of 260 feet, Mallard #1 has a storage capacity of 56 acre-feet and covers a surface area of 4.17 acres. Despite its low hazard potential and fair condition assessment, the dam is regularly inspected by the State Regulatory Agency to ensure its safety and compliance with state regulations.

The dam features an uncontrolled spillway with a width of 25 feet and has a maximum discharge capacity of 1162 cubic feet per second. While Mallard #1 does not have outlet gates, it is equipped with various safety measures to manage potential risks and emergencies. The risk assessment for this dam is categorized as moderate, indicating that there are measures in place to address potential risks and ensure the safety of surrounding areas. Overall, Mallard #1 plays a crucial role in water resource management and climate resilience efforts in the region, making it a significant asset for water enthusiasts and climate advocates alike.