Betty No. 1 is a privately-owned earth dam located in Edgemont, South Dakota, along Bear Creek. Completed in 1956 for irrigation purposes, this dam stands at a height of 32 feet with a hydraulic height of 27 feet and a structural height of 33 feet. It has a length of 2455 feet and a storage capacity of 2029 acre-feet, providing water for agricultural use in the area.

Despite its low hazard potential, Betty No. 1 is in poor condition as of the last inspection in May 2017. The dam features an uncontrolled spillway with a width of 140 feet and one outlet valve. Although it has a moderate risk assessment rating, there are no specific risk management measures or emergency action plans in place. With its location in Wyoming's Converse County, this dam plays a crucial role in water resource management and irrigation for the surrounding agricultural lands.

Water resource and climate enthusiasts may find Betty No. 1 to be an interesting case study in the maintenance and management of aging infrastructure for irrigation purposes. As an earth dam with stone core and soil foundations, its condition assessment and risk factors highlight the importance of regular inspections and maintenance to ensure the safety and efficiency of water storage and distribution systems in the region. Further monitoring and potential upgrades may be necessary to address the dam's current poor condition and mitigate any potential risks associated with its continued operation.