(ST. LOUIS, AP) — Businesses that move products on the Mississippi River continue to seek the government’s help as the river approaches historic lows.

The Army Corps of Engineers on Friday began reducing the outflow from an upper Missouri River reservoir to ease drought conditions in that part of the country.

The move will reduce the amount of water flowing into the Mississippi River and could mean further restrictions on barge traffic by early December, or perhaps even closure of the river from St. Louis to Cairo, Ill.

Ann McCulloch of the trade group the American Waterways Operators says restrictions or closure could cost businesses millions of dollars.

Companies and trade groups are asking the corps to restore the flow, and to expedite removal of rock formations in the Mississippi that impede barge traffic.