Wetlands are important for many reasons. They support a large volume of plants, which in turn supply cover and food for animals. Wetlands retain water like a giant sponge - flowing water is slowed as it passes through and is absorbed by plants and soils. By soaking up the water, wetlands not only prevent floods but make water available during a drought. They also help reduce the threat of low salinities in coastal waters.
Wetlands can also clean up contaminated water.
Organisms and soils in a wetland act as a filter for fertilizers and other pollutants. Algae and bacteria break down mineral and organic matter, which can then be used as food for plant life. Some municipalities use wetlands as the final stage in treating waste from sewage treatment plants . Other communities are actually constructing wetlands for this purpose. However, wetlands can't perform miracles.