Coastal Wetlands
NOAA defines coastal wetlands as all wetlands in coastal watersheds, i.e., watersheds that drain to the ocean or to an estuary or bay (for information on coastal watersheds, see the section on "Where are Coastal Wetlands?"). Although many people think of tidal salt marshes when they hear "coastal wetlands," there are many wetlands in coastal areas that are neither tidal nor salty. Coastal wetlands include salt marshes, bottomland hardwood swamps, fresh marshes, seagrass beds, mangrove swamps, and shrubby depressions known in the southeast United States as "pocosins."
Like all wetlands, coastal wetlands are sometimes easy to recognize, but also can be very difficult to distinguish from uplands. Coastal wetlands can occur in areas with standing water, tidal water, or only periodic or seasonal flooding. Since many coastal environments are shifting and changing (due to erosion, sea level rise, subsidence, or human alteration), coastal wetlands are very dynamic places. For example, barrier beaches along the Atlantic coast tend to "roll" toward the land as a result of sea level rise, causing the salt marshes directly behind these beaches to be buried by the beach as new areas of salt marsh become established behind the beach on areas where wind or water carries sand. Coastal marshes around brackish ponds can change from salt marshes to fresh marshes if the pond's connection to salt water is blocked by drifting sand or a road. Further inland, fresh marshes along coastal streams may expand or shrink depending on how the river channel moves. Coastal wetlands are sensitive not only to natural processes, but also to human alterations, water sources, and the surrounding landscape.
Common Wetland Types:
(Saltwater Wetlands), (Freshwater Wetlands)
Coastal wetlands are often categorized based on whether the water is salty or fresh, whether the wetland is tidal or non-tidal, and the wetland’s dominant vegetation.
