Lost Creek E-1, also known as Lost Creek Watershed Site E-1 Dam, is a local government-owned structure located in Seneca, Missouri. Built in 1977 by the USDA NRCS, this earth dam stands at a height of 46 feet and spans 735 feet in length, with a storage capacity of 200 acre-feet. Its primary purpose is flood risk reduction for the TR-Lost Creek watershed, covering a drainage area of 736 square miles.

The dam's spillway, an uncontrolled type with a width of 100 feet, ensures a maximum discharge of 442 cubic feet per second. Despite its high hazard potential, Lost Creek E-1 has been assessed as satisfactory in condition, last inspected in June 2016 with an inspection frequency of three years. While the risk assessment deems the dam to have a moderate risk level, with appropriate risk management measures, it continues to serve its intended function effectively, safeguarding the local community from potential flooding events.

With its strategic location and design, Lost Creek E-1 remains a vital component of the flood risk reduction infrastructure in Newton County, Missouri. Managed and regulated by the DAM AND RESERVOIR SAFETY PROG, this dam exemplifies the importance of proactive maintenance and inspection protocols to ensure the safety and efficiency of water resource management systems in the face of changing climate conditions.