The reason that wetlands are wet varies. Since most wetlands are located in low-lying areas, rain and runoff help to keep the area saturated. Other wetlands stay wet because they're next to rivers or other bodies of water that regularly overflow their boundaries. Beavers, for example, are important wetland builders. The rivers and streams that they dam often flood large areas, turning meadows into marshes and parts of the forest into swampland.
People sometimes create wetlands too- both intentionally and unintentionally.
For example, a state game and fish agency might flood an area so that waterfowl will have more places to breed. On the other hand, a swamp or marsh might get its start accidentally when construction blocks the natural flow of water and causes a stream to back up and overflow. Here's a look at some of the important functions they perform. An easy and cheap way of controlling floods is to leave wetlands in their natural state. That's because wetlands act like giant, shallow bowls.