HAMBURG, Iowa — Water that has been pouring through a breached Missouri River levee finally reached a makeshift barrier that is a small Iowa town’s only hope of avoiding major flooding, authorities said Thursday.

The water, which breached the primary levee south of Hamburg on Monday and has been slowly advancing over the surrounding farmland, reached the 8-foot-tall levee late Wednesday, Army Corps of Engineers spokesman Carlos Lazo said. There were no immediate problems reported along the structure, where officials expect about 5 feet of water to eventually collect.