Eureka is a gravity dam located on the Fox River in Winnebago, Wisconsin, completed in 1920 with a height of 8 feet and a length of 209 feet. The dam serves multiple purposes, including flood control and water storage, with a maximum storage capacity of 124 acre-feet and a normal storage of 33 acre-feet. The drainage area for the dam is 1492 square miles, with a maximum discharge capacity of 4560 cubic feet per second.

The dam is owned and regulated by the Wisconsin Department of Natural Resources (WIDNR), with state permitting, inspection, and enforcement in place. It has a low hazard potential and is currently in fair condition, assessed in May 2020. While the dam has an uncontrolled spillway and no locks, it has an inspection frequency of 10 years and is located within the jurisdiction of the state of Wisconsin.

Overall, Eureka Dam plays a crucial role in water resource management and flood prevention in the region. Its moderate risk assessment suggests the need for continued monitoring and management measures to ensure its safety and efficiency in the face of changing climate conditions and water resource demands.