The U.S. Coast Guard says 97 boats and barges are waiting for passage along an 11-mile stretch of the Mississippi River that has been closed because of low water levels.

Coast Guard spokesman Ryan Tippets told The Associated Press on Monday that the stretch of river near Greenville, Miss., has been closed intermittently since Aug. 11, when a vessel ran aground.

Tippets says that the area is currently being surveyed for dredging and that a Coast Guard boat is currently replacing eight navigation markers. He says 40 northbound vessels and 57 southbound vessels are currently stranded and waiting for passage.

Tippets says it is not immediately clear when the river will reopen. He says the stretch of river that has been closed was a possible site for more groundings.