DES MOINES, Iowa (AP) — Several northwestern Iowa cities are dealing with the worst flooding ever while others downstream brace for surges on the Rock, Big Sioux, and Missouri rivers. Rock Rapids, a town of 3,000, lost its water supply. Mayor Jason Chase says it’s back on but he’s awaiting tests results to show water is safe to drink. He says 60 homes have waist-deep water in them, and several families remain in a shelter. The Rock River is receding after cresting at a record 27 feet.