A sudden temperature change has caused an exchange in the Barren Fork River that has left a bad taste in the mouths of some Warren County residents. “The river has turned over,” said McMinnville Water Treatment Plant manager Ricky Morton. He says the warmer water at the top of the river has flip-flopped with cooler water at the bottom of the river because of the sudden change in the water’s temperature.“Usually, less dense water is at the surface and denser water is at or near the bottom,” Morton said.