Mississippi River Lock and Dam 4, also known as Pool 4, is a Federal-owned structure located in Buffalo County, Wisconsin. Completed in 1935, this concrete dam serves primarily for navigation purposes on the Mississippi River, with a dam height of 22 feet and a hydraulic height of 27 feet. The dam features a controlled spillway with a width of 1130 feet and a single lock with a length of 600 feet and a width of 110 feet.

This dam plays a crucial role in maintaining a navigation pool for river traffic, with a maximum discharge capacity of 269,000 cubic feet per second. Despite being classified as a moderate-risk dam by the US Army Corps of Engineers, ongoing risk management measures are in place to address potential issues such as seepage, erosion, and deteriorated infrastructure. Regular inspections, maintenance, and public engagement efforts contribute to reducing risks and ensuring the safety of the surrounding area.

Overall, Mississippi River Lock and Dam 4 stands as a vital structure for river navigation and flood risk management, with continuous efforts to mitigate potential hazards and ensure the dam's proper functionality. Its strategic location and design make it an essential component in the broader water resource and climate management efforts along the Mississippi River.