Officials with the US Army Corps of Engineers say low water levels that are restricting shipping traffic and causing barges to run aground on the Mississippi River are expected to continue through the harvest season.  Major General John Peabody announced this week five harbors in Tennessee, Missouri, Arkansas, and Mississippi are closed and several others have limited access.  Peabody says weather forecasts show this will persist through at least October.  Corps spokesman Rene Poche  tells KZIM KSIM they are working overtime to keep the navigation channel passable from Cape to New Orleans.  Poche says the Coast Guard Wednesday re-opened an 11-mile stretch of the River near Mississippi, replacing it with a five-mile zone where only light vessels can pass.  The River is at 7-feet at Cape, 8-feet at Cairo, and is forecast to fall another 9-inches by Tuesday.  The Cape reading is the lowest seen since 2006.