Lost Creek 4 is a local government-owned Earth dam located in Pepin, Wisconsin, designed by the USDA NRCS and completed in 1959. This dam, with a height of 35 feet and a hydraulic height of 16 feet, serves the primary purpose of flood risk reduction along the tributary to Lost Creek. It has a normal storage capacity of 9 acre-feet and a maximum storage capacity of 139 acre-feet, with a drainage area of 1.1 square miles and a maximum discharge of 106 cubic feet per second.

Despite being classified as having a low hazard potential and fair condition assessment, Lost Creek 4 is regulated, permitted, inspected, and enforced by the Wisconsin Department of Natural Resources. The dam's spillway is uncontrolled, and it spans a length of 520 feet with a surface area of 3 acres. The dam's inspection frequency is every 10 years, with the last inspection conducted in May 2015. The risk assessment for Lost Creek 4 is moderate, indicating a level 3 risk.

Overall, Lost Creek 4 is an essential infrastructure for flood risk reduction in the area, with a history dating back to the late 1950s. Managed and regulated by the state, this dam plays a crucial role in protecting the surrounding community from potential flooding events. With a moderate risk assessment and fair condition, ongoing maintenance and monitoring are necessary to ensure the continued effectiveness and safety of Lost Creek 4 for years to come.