Weeks of heavy rains and high water are making early summer tricky on the Mississippi River, where two towing vessels collided on last week on the lower river.

The vessels, the 195’x54’ American Heritage and the David G. Schert, collided early Thursday afternoon near Vacherie, La., in St. James Parish. Several barges broke loose, and one barge carrying caustic soda overturned, according to the Coast Guard New Orleans Sector.

The capsized barge was out of the navigable waterway on the right descending bank, and the others were safely recovered after a temporary closing of Veterans Bridge across the river to Gramercy, La., the Coast Guard said. An unknown amount of caustic soda solution was released into the river, in the worst case up to 23,672 gals., but “this product will dissipate and neutralize soon after entering the water, posing minimal risk in the immediate vicinity of the barge,” the Coast Guard said.

Water supply authorities and the river parish governments were notified of the spill, and the river remained open to all traffic. The Coast Guard is investigating the cause of the accident.

A few miles upriver from the scene, the U.S. Army Corps of Engineers river gauge at Donaldsonville, La., recorded 24.21’ at noon Saturday, shy of the 27’ flood stage. Conditions throughout the basin led the Coast Guard Eighth District to issue an advisory for the Independence Day weekend.

“The Mississippi River and many of its tributaries will experience high water levels during the Fourth of July weekend. The Coast Guard highly recommends boaters assess the risks associated with high water and take appropriate precautions,” the Coast Guard said. “While commercial vessel traffic is still open, some locks and dams may experience closures. Mariners should listen for notice to mariners on marine band radio channel 16 for river restrictions and closure updates.”