Bill Chelmowski, U.S. Army Corps of Engineers, St. Paul District survey technician, operates an airboat on the Mississippi River at Lake Pepin, near Lake City, Minnesota, Feb. 17. Chelmowski and a team of surveyors were measuring the ice thickness on the lake to help the navigation industry determine when it’s safe to begin the 2026 navigation season. The St. Paul District navigation program provides a safe, reliable, cost-effective and environmentally sustainable waterborne transportation system on the Upper Mississippi River for the movement of commercial goods and for national security needs. To do this, the district maintains a 9-foot navigation channel and 13 locks and dams from Minneapolis to Guttenberg, Iowa. Keeping this system open is vital to the nation’s economy.