After Opiki, it slows and has a lower gradient, meandering over the Manawatu Plains; its bed at this point is mud and silty sand. In its meandering and frequent shifting of course it has created oxbow lakes, lagoons, and swamps. Sediment deposited along its course has created levees, higher than the surrounding plain; when the river is in flood it overflows these and creates wetlands. The Manawatū reaches the Tasman Sea at Foxton Beach, on the west coast of the North Island, creating the Manawatu Estuary.