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Wetlands- (Chesapeake Bay Program)
Marsh grasses, Blackwater National Wildlife Refuge - {description} Sunset over marsh, Tangier Island - {description} Aerial river runs through a wetland - {description} Great blue heron in marsh - A great blue heron (Ardea herodias) hides in a Chesapeake Bay wetland. Newly planted marsh grasses, Barren Island - {description} Marsh, Hoopers Island - A marsh and eroding island near Hoopers Island, Maryland
(Chesapeake Bay Program)


Wetlands are transitional areas 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 Types of Wetlands Are Found in the Chesapeake Bay Watershed?

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

  • Tidal, or estuarine, wetlands are flooded with salt or brackish water when tides rise. Tidal wetlands are found along the shores of the Bay and the tidal portions of streams, creeks and rivers.
  • Non-tidal, or palustrine, wetlands contain fresh water. Eighty-six percent of the wetlands in the Chesapeake 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 Chesapeake 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 the health of the Bay and protect shorelines and property, as well as provide opportunities for outdoor activities.

Wetlands Improve and Protect the Chesapeake Bay's Health

Situated between the land and the water, wetlands act as buffers by slowing the flow of pollutants into the Bay and its tributaries. As polluted stormwater runs off the land and passes through wetlands, the trees and grasses in wetlands filter and absorb nutrients, suspended sediments and chemical contaminants before these pollutants can flow to nearby waterways.

Wetlands also help control erosion. Just like a sponge, wetlands soak up and hold large amounts of flood water and stormwater runoff, gradually releasing the water over time. Wetlands along the edges of streams, creeks, rivers and the Bay stabilize shorelines and protect properties from floods and wave action.

Wetlands are especially important in our cities, towns and suburbs, where development and impervious surfaces increase the rate and volume of polluted stormwater runoff.

Wetlands Provide Important Wildlife Habitat

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

  • Tidal wetlands are a winter home for waterfowl that visit the Chesapeake Bay as they migrate along the Atlantic Flyway.
  • Muskrats, wading birds and other widlife 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. In turn, larger animals depend on these small aquatic species for food.

Wetlands Are Valuable Economically and for Outdoor Activities

Wetlands are economically valuable because they provide opportunities for fishing, crabbing and hunting. Since they are habitat for commercially important fish and shellfish, wetlands are vital to the health of the Chesapeake Bay's commercial fishing industries.

Additionally, many people visit wetlands for popular hobbies and family activities such as boating, bird watching, photography and wildlife study.

Restoring Wetlands

The Chesapeake 2000 agreement charged Chesapeake Bay Program partners with restoring 25,000 acres of tidal and non-tidal wetlands in the Bay watershed by 2010. These wetland acres would be gained through voluntary projects. In 2005, Bay Program partners clarified this goal to track only wetland establishment and re-establishment projects, which represent true gains in wetland acreage.

There are five specific definitions scientists use to track wetland gains:

  • Establishment is creating a wetland where one did not previously exist.
  • Re-establishment is returning a former wetland to its natural, historic state. Usually, former wetlands have been drained for another use, such as agriculture.
  • Enhancement is improving one or more of an existing wetland's functions, such as flooding a seasonal wetland to benefit waterfowl.
  • Rehabilitation is repairing the historic functions of a degraded, existing wetland, such as removing invasive species like nutria and phragmites.
  • Protection is acquiring land or easements of at least 30 years.

Establishment and re-establishment are considered wetland acreage gains, whereas enhancement and rehabilitation only improve the function of existing wetland acres. Protection is not considered to be a gain in acreage or function.



Chesapeake Bay News

Tidal Wetlands Abundance

As of 2010, there were approximately 282,291 acres of tidal wetlands in the Chesapeake Bay watershed’s estuarine drainage area. This marks an increase of 1,289 acres between 2005 and 2010, but a long-term loss of 1,566 acres between 1992 and 2010.

Restoring Wetlands on Agricultural Lands

Between 2010 and 2013, 6,098 acres of wetlands were established, rehabilitated or reestablished on agricultural lands in the Chesapeake Bay watershed. The Chesapeake Bay Program has a goal to create or reestablish 85,000 acres of wetlands by 2025. Under this goal, 83,000 acres should be created or reestablished on agricultural lands.


2005 Wetlands Evaluation

Publication date: November 08, 2005 | Type of document: Policy Memorandum | Download: Electronic Version

The Chesapeake Bay Program recognized the importance of wetlands in Chesapeake 2000, which charged signatories to reach specific goals by 2010. This memo provides an update on the 2005 Wetlands Evaluation and outline the the PSCs decisions…

The Optimization of Benefits from Wetlands Restoration

Publication date: February 01, 2002 | Type of document: Report | Download: Electronic Version

State and federal agencies have been engaged in restoration and creation of wetlands for many years, generally as part of programs focused on habitat and water quality management. In the late 1990s recognition of the growing cumulative loss…

Wetlands and the Chesapeake Bay

Publication date: November 11, 2001 | Type of document: Fact Sheet

Fact sheet describing the functions and values of wetlands , status and trends in wetlands, wetland hot spots, causes of wetland loss, and partnerships for conservation and protection of wetlands

Endorsement of Wetlands Protection and Restoration Goals

Publication date: December 07, 1999 | Type of document: Policy Memorandum | Download: Electronic Version

Wetlands, both tidal and non-tidal, play a critical role in the Chesapeake Bay ecosystem, a role the Chesapeake Bay Program recognized in the 1987 Chesapeake Bay Agreement, the 1989 Chesapeake Bay Wetlands Policy and Directive 97-2,…

Protecting Wetlands II Technical and Financial Assistance Programs for Local Governments in the Chesapeake Bay Region

Publication date: February 01, 1998 | Type of document: Report

This work contains the following themes as they relate to the Chesapeake Bay: The Living Natural Bay/Ecosystems, Environmental Stewardship and Sustainability of the Bay/Stewardship

Directive 97-2: Wetlands Protection and Restoration Goals

Publication date: October 30, 1997 | Type of document: Directive | Download: Electronic Version

Both tidal and non-tidal wetlands critical role in the Chesapeake Bay ecosystem, is emphasized in this in this directive and specific actions are recommended to maintain existing wetland and to restore wetland acreage and functions in order…

Protecting Wetlands: Tools for Local Governments

Publication date: April 01, 1997 | Type of document: Report

This work contains the following themes as they relate to the Chesapeake Bay: The Living Natural Bay/Ecosystems, Environmental Stewardship and Sustainability of the Bay/Stewardship .

Chesapeake Bay Wetlands: The Vital Link Between the Watershed and the Bay

Publication date: March 01, 1997 | Type of document: Report

This work contains the following themes as they relate to the Chesapeake Bay: The Living Natural Bay/Ecosystems

Mitigation Technical Guidance for Chesapeake Bay Wetlands

Publication date: October 01, 1994 | Type of document: Report

The purpose of this guidance document is to clarify the concept of wetland mitigation and to prove a common approach to mitigation that will allow governmental decisions to rely on a sound scientific bases.

Recent Wetland Status and Trends in the Chesapeake Watershed (1982-1989); Technical Reports

Publication date: May 01, 1994 | Type of document: Report

The report includes methods, interpretation of results, results for the Watershed, results by State, wetland loss hotspots, discussion and conclusions and recommendations.

Reassessment Task Force Report on the Chesapeake Bay Wetlands Policy Implementation Plan

Publication date: September 01, 1993 | Type of document: Report

The Wetlands Implementation Plan is designed to achieve the wetlands policy goals of the Chesapeake Bay Agreement. Both guidance and recommendations to restructure the original implementation plan are addressed.

Chesapeake Bay Wetlands Research Recommendations and Program Descriptions

Publication date: January 01, 1993 | Type of document: Report

This is a report on Chesapeake Bay Wetlands Research Recommendations and Program Descriptions.

From Around the Web

Bay FAQs

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Bay Terms

  • Habitat
  • Hydric soil
  • Hydrophyte
  • Nutrients
  • Sediment
  • Tributary
  • Wetland


Bay-Friendly Tips

  • Use Native Plants
  • Plant native flowers, shrubs and trees. They often require less water and can attract birds, butterflies and honeybees.


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