Bar D is a privately-owned irrigation dam located in Custer, Idaho, along Warm Spring Creek and the Salmon River. Built in 1950, this earth dam stands at a height of 26.3 feet and has a storage capacity of 227 acre-feet. The dam serves the primary purpose of irrigation, supporting agricultural activities in the region.

Despite being regulated and inspected by the Idaho Department of Water Resources, Bar D poses a significant hazard potential, with a very high risk assessment rating. The condition assessment of the dam is currently fair, with the last inspection conducted in November 2019. The dam features a controlled spillway and slide gates for outlet control, ensuring proper water management and flood prevention.

Water resource and climate enthusiasts interested in the management and maintenance of dams will find Bar D an intriguing case study. From its historical significance in irrigation to its risk assessment and hazard potential, this dam serves as a critical infrastructure supporting agricultural activities while also highlighting the importance of effective regulation and maintenance practices to ensure public safety and water resource sustainability.