ST. LOUIS (AP) -- The Mississippi River crested at St. Louis on Thursday and was beginning a descent unlikely to be interrupted by another round of rain.

The river reached 35 5 feet -- 5.5 feet above flood stage -- at a gauge near the Gateway Arch early Thursday morning but had fallen about a half-foot by midday. The grounds of the Arch remained dry and the flooding caused few problems in the city.

More rain was expected at St. Louis during the weekend "but nothing that will drive any river problems," National Weather Service meteorologist Butch Dye said.

The Mississippi crested earlier this week to the north of St. Louis; crests still were a day or two away to the south. Cape Girardeau, Mo., was bracing for a crest 10 feet above flood stage Friday, though a flood wall protects the community and no significant problems were expected.

Heavy rain last week over much of the Midwest spurred flooding that has swamped hundreds of thousands of acres of farmland, closed roads and endangered a few unprotected towns like Clarksville and Dutchtown in Missouri. A makeshift levee was holding back floodwaters at Clarksville; sandbags were helping to keep Dutchtown dry.

The biggest problem Thursday occurred in far southern Missouri, when a barge struck the Interstate 155 bridge at Caruthersville. The bridge between Missouri and Tennessee was briefly closed for inspection before being reopened. No significant damage was found.

It was the second Mississippi River bridge struck by a barge in the past six days. On Saturday, 114 barges broke free from where they were moored near St. Louis, with four of them striking the Jefferson Barracks Bridge. It reopened after about six hours.

Traffic on the upper Mississippi was at a standstill on Thursday. Barges weren't moving because locks were closed. On Wednesday, the U.S. Coast Guard suspended recreational boating over much of the Illinois and Missouri rivers.

The Coast Guard said the fast current and large amounts of debris make travel on the rivers dangerous.

"Our pre-eminent concern is safety and currently none of the region's major rivers are safe for recreational operation," Coast Guard Capt. Byron Black said. "The debris fields are immense, the river current is twice its normal flow rate, and many unseen dangers exist under the water."

Earlier this week a father and his 15-year-old son had to be rescued from the Mississippi south of St. Louis when their fishing boat became stranded.