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Wetlands are critical in supporting the healthy waters and diverse wildlife of the Chesapeake Bay watershed. Located where land meets water, wetlands act like a sponge, soaking up storm surges and trapping polluted runoff. Wetlands also provide habitat to hundreds of fish, birds, mammals and invertebrates. But development, invasive species and sea level rise threaten these important areas. Protecting and restoring wetlands is a key way to promote clean water, healthy habitats and a restored Bay.

What is a wetland?

Located where land meets water, wetlands are vital habitats in the Chesapeake Bay watershed. Wetlands act like a sponge, soaking up stormwater and dampening storm surges. By trapping polluted runoff, wetlands help slow of the flow of nutrients, sediment and chemical contaminants into rivers, streams and the Bay. Hundreds of species of fish, birds, mammals and invertebrates depend on wetlands, and humans rely on wetlands to support recreational fishing and hunting across the watershed.

But shoreline development, sea level rise and invasive species pose major threats to these critical habitats: development along beaches and shorelines blocks the creation of further wetland habitat and creates excess sediment; sea level rise floods wetlands with saltwater, destroying plants faster than they can populate higher ground; and invasive plants and animals can crowd out native species or damage wetland habitat.

What types of wetlands are found in the Chesapeake Bay region?

A wetland is defined by its soils and vegetation. Some wetlands may be saturated with water throughout the year, while others are not always visibly wet. All wetlands are dominated by “hydrophytes”—plants that are adapted for life in wet soils—and have hydric soils, meaning they are periodically saturated or flooded.

Two broad categories of wetlands are 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 and make up 86 percent of the wetlands in the watershed. Palustrine wetlands are located on floodplains bordering streams and rivers, along the shorelines of lakes and ponds or covering broad, flat areas where water may collect (such as many areas on the Delmarva peninsula).

Wetlands can be further distinguished by the varieties of plants that grow there:

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

Why are wetlands important?

Wetlands provide critical habitat for hundreds of species of fish, birds, mammals and invertebrates while improving the health of the Bay by collecting and storing flood waters, filtering polluted runoff and weakening storm surges. Wetlands also help 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 filter and absorb nutrients, sediment 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, releasing the water slowly 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 offer economic and aesthetic value

Humans rely on wetlands both for their economic value and natural beauty. As key habitat for hundreds of species, wetlands provide opportunities for fishing, crabbing and hunting. Wetlands are vital to the health of the Chesapeake Bay's commercial fishing industries, as they are habitat for commercially important fish and shellfish.

Wetlands are also beautiful locations where people can connect with nature. Many people visit wetlands for popular hobbies and family activities such as boating, bird watching and photography.

How are wetlands threatened?


Development along beaches and shorelines can send excess sediment into the Bay. Man-made, hardened shorelines—those lined with rocks, wood or concrete—can block the formation of wetland habitat and increase the amount of sediment suspended in the water.

Sea level rise

Over the past century, Bay waters have risen about one foot, and are predicted to rise another 1.3 to 5.2 feet over the next 100 years. As water levels rise, so will coastal flooding and erosion. Marshes and wetlands will be inundated with saltwater and will disappear faster than wetland plants can populate higher ground. A loss of marshes and wetlands will mean a loss of the habitat that traps pollution and provides food and shelter to fish, shellfish and birds.

Invasive species

Invasive plants are harmful to wetlands for several reasons. Invasive plants:

  • Grow and reproduce rapidly, killing and outcompeting other species in the process;
  • Lower the quality of available food sources and shelter options for wildlife;
  • Eliminate the native host plants of insects; and
  • Compete with native plants for pollinators.

Phragmites, purple loosestrife and Japanese stiltgrass are three invasive plants that have become permanent residents of Chesapeake wetlands.

Invasive animals can also alter wetland conditions. Nutria have had long-term, devastating impacts on the region’s wetlands; since their introduction to Blackwater National Wildlife Refuge in 1943, the mammals have destroyed more than 7,000 acres of the refuge’s marshland.

How are wetlands being restored?

Retaining and expanding wetlands is a critical way to reduce pollution, provide habitat and restore the Bay. The Chesapeake Bay Program has a long history of working to protect and restore wetlands in the Bay region. Between 2010 and 2014, 6,191 acres of wetlands were established or restored on agricultural lands in the Bay watershed.

There are five definitions scientists use to track wetland restoration:

  • 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 functions of an existing wetland, such as flooding a seasonal wetland to benefit waterfowl.
  • Rehabilitation is repairing the historic functions of a degraded wetland, such as removing invasive species like nutria and phragmites.
  • Protection is acquiring land or easements of at least 30 years.

Current restoration goals

In the 2014 Chesapeake Bay Watershed Agreement, our partners committed to the goal of creating or reestablishing 85,000 acres of wetlands and enhancing an additional 150,000 acres of degraded wetlands by 2025.

Take Action

For Chesapeake Bay restoration to be a success, we all must do our part. Our everyday actions can have a big impact on the Bay. By making simple changes in our lives, each one of us can take part in restoring the Bay and its rivers for future generations to enjoy.

To support wetlands in the Bay watershed, consider planting trees and grasses to create more wildlife habitat. You can also choose and use native plants to support the plants and animals that have adapted to this region.



Chesapeake Bay News

In The Headlines

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 2014, 6,191 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. Just over seven percent of the wetlands on agricultural lands goal has been achieved.

Bay 101: Wetlands

February 08, 2016

Wetlands are some of the most diverse ecosystems on the planet, and there are roughly 500,000 acres of wetlands in the Chesapeake Bay watershed.

Park Naturalist Greg Kearns of the Maryland-National Capital Park and Planning Commission and Naturalist and Environmental Coordinator Liana Vitali of Jug Bay Wetlands Sanctuary describe the importance of wetlands for wildlife and people. Learn about wild rice, migrating birds and some of the threats faced by Jug Bay and other wetlands habitats.


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

  • What makes an area a wetland?
  • What threatens wetlands?
  • What services do wetlands provide?


Bay Terms

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


Bay-Friendly Tips

  • Use Native Plants
  • Native flowers, shrubs and trees often require less water and can provide food and habitat for birds, butterflies and honeybees.


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