Drought and below-average rainfall have caused the Mississippi River to fall to near-record lows [File: Jeff Roberson/AP Photo]

Iowa City, October 29 (RHC)-- Adam Thomas starts harvesting soybeans on his farm in the U.S. state of Illinois when the dew burns off in the morning.  This year, dry weather accelerated the work, allowing him to start early. His problem was getting the soybeans to market.

About 60 percent of the Midwest and northern Great Plain states are in a drought. Nearly the entire stretch of the Mississippi River — from Minnesota to the river’s mouth in Louisiana — has experienced below average rainfall over the past two months.

As a result, water levels on the river have dropped to near-record lows, disrupting ship and barge traffic, which is critical for moving recently harvested agricultural goods such as soybeans and corn downriver for export.  Although scientists say climate change is raising temperatures and making droughts more common and intense, a weather expert says this latest drought affecting the central United States is more likely a short-term weather phenomenon.

The lack of rain has seriously affected commerce. The river moves more than half of all US grain exports, but the drought has reduced the flow of goods by about 45 percent, according to industry estimates cited by the federal government. Prices for rail shipments, an alternative to sending goods by barge, are also up.   “It just means lower income, basically,” said Mike Doherty, a senior economist with the Illinois Farm Bureau.

Thomas farms at the confluence of the Ohio and Mississippi rivers and doesn’t own enough grain storage to wait out the high costs of shipping. “I’ve had to take a price discount,” he said.

Thousands of visitors last weekend walked across a typically submerged riverbed to Tower Rock, a protruding formation about 160 km (100 miles) southeast of St Louis.  It’s the first time since 2012 that people could make the trek and stay dry.  On the border of Tennessee and Missouri where the river is 0.8 km (a half-mile) wide, four-wheeler tracks snake across vast stretches of exposed riverbed.

In a badly needed break from the dry weather, the region finally received some rain this week.  “It is kind of taking the edge off the pain of the low water, but it is not going to completely alleviate it,” said Kai Roth of the Lower Mississippi River Forecast Center, adding that the river needs several rounds of “good, soaking rain”.

Barges are at risk of hitting bottom and getting stuck in the mud. This month, the US Coast Guard said there had been at least eight such groundings.  Some barges touch the bottom but don’t get stuck.  Others need salvage companies to help them out.  Barges are cautioned to lighten their loads to prevent them from sinking too deep in the water, but that means they can carry fewer goods.

To ensure that vessels can travel safely, federal officials regularly meet, consider the depth of the river and talk to the shipping industry to determine local closures and traffic restrictions.  When a stretch is temporarily closed, hundreds of barges may line up to wait.

“It’s very dynamic: Things are changing constantly,” said Eric Carrero, the Coast Guard’s director of western rivers and waterways.  “Every day, when we are doing our surveys, we’re finding areas that are shallow and they need to dredge.”  After a closed-down section is dredged, officials mark a safe channel and barges can once again pass through.

In some places, storage at barge terminals is filling up, preventing more goods from coming in, according to Mike Steenhoek, executive director of the Soy Transportation Coalition. He said the influx of grain into a compromised river transportation system is like “attaching a garden hose to a fire hydrant”. High costs for farmers have led some to wait to ship their goods, he added.