FILE - In this Nov. 28, 2012 file photo, a tow switching barges pulls an empty barge along side one filled with soybeans at an Archer Daniels Midland grain river terminal along the Miss

 

              FILE - In this Nov. 28, 2012 file photo, a tow switching barges pulls an empty barge along side one filled with soybeans at an Archer Daniels Midland grain river terminal along the Miss
FILE - In this Nov. 28, 2012 file photo, a tow switching barges pulls an empty barge along side one filled with soybeans at an Archer Daniels Midland grain river terminal along the Mississippi River in Sauget, Ill. From Montana to West Virginia, officials from across the country have written to President Barack Obama urging him to intervene _ or not _ in a dispute about whether water from the Missouri River’s upstream reservoirs should be released to flow into the Mississippi River, where low water levels have imperiled commercial traffic along a 180-mile stretch between St. Louis and Cairo, Ill. (AP Photo/Jeff Roberson, File)