By Michael Hirtzer
(Reuters) - The Mississippi River was reopened on Thursday along a five-mile stretch near St. Louis as waters receded after one of the worst floods on record halted barge traffic for four days on the main route to global markets on the U.S. Gulf Coast.
The U.S. Coast Guard allowed southbound river traffic to resume along a five-mile stretch of the Mississippi that had been closed since Monday, said Colin Fogarty, a public affairs officer at the agency.
Northbound traffic was expected to resume later on Thursday, Fogarty added.
Also reopening was Lock 24 in Clarksville, Missouri, and Lock 27 in Granite City, Illinois, according to Michael Peterson, a spokesman for the U.S. Army Corps of Engineers.
But Lock 25 in Winfield, Missouri, remained closed because waters have not receded enough. The entire stretch of the river was also remained closed for recreational watercraft.
Record rainfall in the Midwest from March to May resulted in high and fast-moving waters on the busiest U.S. river.
At least eight tows and 63 barges were moored this week after government officials deemed the waterway unsafe for navigation - waters were high enough that tows risked hitting St. Louis' bridges, Fogarty said.
Waters on the Mississippi at St. Louis on Thursday receded to the moderate flood stage of 38.9 feet, after cresting this week at 40.5 feet, according to the National Weather Service.
It was the fourth highest recorded water level since the St. Louis Army Corps gage was installed in 1861.
"Anything above 40 feet of water is a real indicator that the river needs to be closed," Fogarty said. "The most obvious danger is bridge clearance."
In January, the river was nearly closed after last summer's drought left waters at levels dangerously low for navigation.
Some 60 percent of all U.S. grain exports is transported via the Mississippi River and its tributaries from farm areas in the Midwest to export terminals at the Gulf Coast. Shippers also rely on the inland waterway system to transport numerous other commodities, including fertilizer, coal, crude oil and steel.
(Reporting by Michael Hirtzer in Chicago; additional reporting by Karl Plume)