ST. LOUIS (AP) — U.S. Sen. Roy Blunt of Missouri may seek a presidential emergency declaration in an effort to keep barges moving on the drought-riddled Mississippi River.

The Army Corps of Engineers on Friday began reducing the outflow from an upper Missouri River dam in South Dakota. That means less water coming down the Missouri and into the Mississippi River. The already-low Mississippi River level is dropping as a result and could get so low that barge traffic will be severely restricted or even halted by mid-December.

Nearly 80 members of Congress, three governors and many waterway operators have asked the corps to reconsider. Blunt said in a telephone news conference Tuesday that the next step is to evaluate asking for a presidential declaration that would restore the Missouri River flow.