Wetlands

Wetlands are transitional zones between land and water. While some wetlands are noticeably wet, others do not always have visible water. An area is defined as a wetland based on its soils and vegetation.

• All wetlands are dominated by hydrophytes, which are plants that are adapted for life in wet soils.
• Wetlands also have hydric soils, which are soils that are periodically saturated or flooded.

What kinds of wetlands are found in the Bay watershed?

There are two broad categories of wetlands found in the Bay watershed:

• Tidal, or estuarine, wetlands are tidally flooded with salt or brackish water. They are usually found along the shores of the Bay and its tidal rivers.
• Non-tidal, or palustrine, wetlands are freshwater. Eighty-six percent of the wetlands in the Bay watershed are non-tidal. Palustrine wetlands are located:
  • On floodplains bordering streams and rivers.
  • Fringing the shorelines of lakes and ponds.
  • Filling isolated depressions.
  • Covering broad, flat areas at or near sea level where water may collect (such as many areas on the Delmarva Peninsula).

Wetlands are further distinguished by their vegetation.

• Emergent wetlands are made up of grasses, sedges and other leafy, non-woody plants. They are often called marshes or wet meadows.
• Shrub wetlands are characterized by low- to medium-height woody plants. These are often called bogs or shrub swamps.
• Forested wetlands are dominated by trees. These include wooded swamps and low-lying hardwood forests near rivers. Sixty-eight percent of the wetlands in the Bay watershed are forested.

How are wetlands important?

Wetlands provide critical habitat for hundreds of species of fish, birds, mammals and invertebrates. They also improve water quality and protect shorelines and property, as well as provide economic and recreational opportunities.

Water Quality

Poised between the land and the water, wetlands act as buffers by regulating the flow of pollutants into the Bay and its tributaries.

• As water runs off the land and passes through a wetland, suspended sediments are trapped by vegetation and settle into the wetland soil.
• Wetland vegetation filters excess nutrients and suspended solids from precipitation and stormwater before they flow into local waterways or soak into groundwater supplies.
• Chemical contaminants are absorbed and converted by wetlands into less toxic forms.

Wetlands also help control erosion and flooding.

• Just like a sponge, wetlands soak up and hold large amounts of flood and stormwater, then gradually release them.
• Wetlands are especially important in urban and suburban areas where impervious surfaces increase the rate and volume of runoff.
• Coastal wetlands act as a protective buffer against erosion by slowing wave action against the shoreline.

Habitat

Countless species of wildlife that visit or live in the Bay watershed depend on wetlands for their survival.

• Tidal wetlands are the wintering grounds for migratory waterfowl that visit the Bay via the Atlantic Flyway.
• Other wildlife, including muskrats and wading birds, rely on wetlands for food and cover.
• Many commercially valuable species of fish and shellfish use wetlands as spawning or nursery areas.
• Thousands of aquatic species, including worms, snails, insects, mussels, tiny crustaceans and reptiles and amphibians, thrive in wetlands and are food for other organisms.

Economic and Recreational Opportunities

Economically, wetlands provide opportunities for fishing, crabbing and hunting. Popular recreational wetland activities include boating, bird watching, photography and wildlife study.