Farm and business groups are joining several Midwestern governors in asking President Obama to help keep barge traffic moving on the drought-lowered Mississippi River. The river’s low level is threatening to slow or stop those barges carrying everything from coal to corn.

Dave Miller, commodity services director for the Iowa Farm Bureau, says halting traffic would sharply boost shipping costs. Miller says, “Two-and-a-half billion dollars worth of freight that would move during the winter and early spring months is at jeopardy of being shut down if the channel is not maintained with enough flow to get barges through it.”

He says Iowa will be losing barge efficiency in moving grain downriver and in moving next season’s crop fertilizer upstream. “Fifteen barge tow comin’ up the river, each barge displacing 50 trucks,” Miller says, “so it isn’t just the one barge effect, it’s the fact that each tow that moves up the river, you’ve got 750 semis that you’ve got to find to replace that single barge tow that was moving.”

The governors of Mississippi River states and 18 shipping and business interests are asking President Obama to declare an emergency. That would allow the U.S. Army Corps of Engineers to deviate from its master plan and release more water into the Missouri River from reservoirs, which would eventually raise the Mississippi’s level.