Marshes are open flooded wetlands dominated by herbs, grasses, sedges, rushes, or ferns. Marshes may be permanently or seasonally flooded and water can vary from a few centimeters to over a meter in depth. Tennessee marshes fall into three categories. Floodplain marshes are associated with large river floodplains where they receive seasonal overbank flooding. These are found primarily along large river floodplains. Depression marshes are associated with natural depression ponds, sinkhole ponds, and lakes. Spring-fed marshes are associated with large artesian springs.