Heading north as one approaches the underpass under Needmore Road on the Great Miami River Trail, you will pass a couple of signs...
From time to time the Great Miami River overflows its bank and floods the area under the Needmore Road bridge and also the GMR Trail that passes under the bridge. The flood waters will linger for a day or more and deposit a lot of mud. Maintenance responsibilities for this section of trail fall to Five Rivers MetroParks and clearing that mud is an important task. The mud can make the trail difficult to traverse in that location, if not impossible for bikes.
Recently, Five Rivers completed a project to make clearing the mud easier. The project added concrete shoulders to the trail under the bridge to allow for safer and easier maneuvering of trail sweeping equipment. The shoulders will not prevent flood waters from reaching the trail, nor will they reduce the amount of mud. Rather they will simply make the trail more accessible for their sweeper equipment. Here's what the shoulders look like..
By the way, you can access information about river levels along the Great Miami River Trail from the Miami Conservancy District here. Check that page if you are concerned that your trip along the GMR Trail may be interrupted by high water. In the future, however, flood mud should be more quickly cleared in this Needmore location.