ST. LOUIS (AP) — Illinois Gov. Pat Quinn and U.S. Sen. Roy Blunt of Missouri are joining the chorus expressing concern over the Army Corps of Engineers' plan to reduce flow from a Missouri River reservoir, a move that could significantly affect shipping on the Mississippi River.

The corps will drastically reduce the Missouri River flow at Gavins Point Dam in far southeastern South Dakota on or around Nov. 23. Plans call for the current amount of release — 36,500 cubic feet per second — to eventually decline to 12,000 cubic feet per second over the course of several days.

Jody Farhat, chief of the Water Management Division for the Northwestern Division of the corps, said Thursday the move is necessary because of drought conditions on the upper Missouri River.