LEBANON, Mo. » No matter that this has been the summer of endless floods.

No matter that the Missouri to the west, the Mississippi to the east and countless crisscrossing tributaries in between have rejected their banks en masse, as if the rivers of the region have been conspiring to swamp the nation’s entire midsection.

Because on hot summer days, that human impulse to head for water still prevails, and the streams and rivers and lakes of the Ozarks overflow with humanity.

The visitors here come to engage with nature rather than contemplate its mysteries. They wrestle fish out of the water, tow one another behind speeding boats and reinterpret vessels — to sometimes shocking effect — as floating nightclubs.

Others simply float.

Here on the Niangua River, one of countless spring-fed riffles cooling these mountains, inflated tubes bob alongside dented metal canoes and rubber rafts in great flotillas left to the captainship of the current. Once, a boater sailed these waters atop an inflatable bed.

A journey down a slow-moving, four-mile section of the Niangua reveals a river transformed by the sights and sounds of this nonnative species: the warbling of Lynyrd Skynyrd; the snap and fizz of Busch Light cans popping open; and occasional mating calls shouted between boats.

This is not a serious river — in spirit or in strength — but there are occasionally mishaps.

A fallen tree ensnared a boat occupied by sunbathers who forgot where they had put the paddles.

A small storm swept in, the lightning and marble-size hail chasing boaters to search for refuge on the gravel banks.

And at journey’s end, a quick bend in the river flipped a vessel, seeding the water with cans of beer. They bounced along the surface, waiting to be harvested by a lucky fisherman downstream.

© 2011 The New York Times Company