Barge operators, cargo shippers and other associations called on the Obama administration today to declare a state of emergency on the Mississippi River in order to ensure its water levels are suitable for commerce in the coming months.

The river's levels may drop to historic lows in December, prompting the Army Corps of Engineers to reduce the flow of water into it from the Missouri River to secure enough water for the regions in the north. The corps estimates parts of the river would be unnavigable next month under current drought conditions.

The Midwest has not seen a drought as severe as this one in more than five decades, analysts say. With bipartisan backing from state and congressional lawmakers, these groups are also calling for the immediate removal of high rock pinnacles underwater, which could damage cargo ships or impede them from delivering key commodities.

Tom Allegretti, president of the American Waterways Operators, said the emergency declaration would allow the "swift removal of the rock pinnacles and assurance of sufficient flows from the Missouri River while the rock removal work is taking place."

Already the governors of Missouri, Illinois and Iowa, as well as 15 U.S. senators and 62 House members, have called on the administration to keep the river operable.

Curbing the flow of water to the Mississippi River would lead to the paralysis of about $7 billion in commercial trade, groups such as the National Waterways Conference, the National Corn Growers Association, the American Petroleum Institute and 15 others said in a letter to the president.

They asked Obama and the Army Corps to "release such water" as needed from Missouri River reservoirs to preserve a 9-foot navigation channel along the Mississippi.

"Immediate action is needed to prevent catastrophic consequences to the economy of the American heartland," the groups wrote. "The urgent need to avert this impending economic disaster has been widely recognized by federal and state policymakers."

Shutting down the Mississippi River could affect the deliveries of more than 7 million tons of agricultural products worth $2.3 billion, as well as more than 700,000 tons of crude oil said to be worth $534 million, according to the group's letter.

"Substantial curtailment of navigation will effectively sever the country's inland waterway superhighway, imperil the shipment of critical cargo for domestic consumption and for export, [and] threaten manufacturing industries," the groups added.

Federal authorities, such as the corps and the Federal Emergency Management Agency, are looking at ways to ensure environmental stability as well as the safety of nearby residents living with the drought.

Army Corps officials said they intend to keep the Mississippi open for business as long as they can. They say they could do this by dredging and removing some underwater rock formations.

The corps is responsible for keeping the 9-foot channel through the river that was built in the 1930s using a system of pools, locks and dams that keeps water levels at an easily navigable depth.