 The Nepean River rises to the south in the Woronora Plateau, and wraps around the western edge of the city.Swamps and lagoons are existent on the floodplain of the Nepean River, one being Bents Basin, which is also a recreational area.Where the Nepean turns east it becomes the Hawkesbury River, which winds through the Hornsby Plateau before emptying into Broken Bay.