Kayakers and paddle boarders float down a channel in the Bonneville Salt Flats of northwestern Utah, USA. Salt flats (also known as salt pans) are formed when a body of water evaporates, leaving behind a surface of salt and other minerals. This aqueduct transports saltwater to nearby evaporation ponds where potash is extracted and used as fertilizer. Covering about 40 square miles (100 square km), Bonneville is the largest of many salt pans located west of the Great Salt Lake.