(LAKE CITY, Minn.) — The season’s first towboat to push barges on the Mississippi River in Minnesota will be much later than usual this year, the Post-Bulletin newspaper of Rochester reported. Maintenance at Lock and Dam 25 near St. Louis is holding up commercial traffic on the upper river. The average first date of towboat traffic above Alma, Wis., is March 17, but this year no one will make it up the river until well past April 1.