Eau Pleine is a gravity dam located on the Big Eau Pleine River in Marathon, Wisconsin, just 20 miles from Stevens Point. Completed in 1937, this hydroelectric facility serves multiple purposes, including recreation. With a height of 45 feet and a length of 8,599 feet, the dam has a storage capacity of 98,140 acre-feet and covers a surface area of 6,677 acres. It has a controlled spillway with a width of 88 feet and a maximum discharge of 20,767 cubic feet per second.

Managed by the Federal Energy Regulatory Commission, Eau Pleine is a significant structure in the region, providing power generation and recreational opportunities. Despite its high hazard potential, the dam's condition assessment is not available, and its risk assessment indicates a very high risk level. Emergency action plans have been prepared and updated regularly to ensure the safety of the surrounding communities in case of a catastrophic event. With its historical significance and strategic location, Eau Pleine stands as a key player in water resource management and climate resilience efforts in Wisconsin.