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Discover the Chesapeake

The Chesapeake Bay - the largest estuary in the United States - is an incredibly complex ecosystem that includes important habitats and food webs. The Bay and its rivers, wetlands and forests provide homes, food and protection for diverse groups of animals and plants. Fish of all types and sizes either live in the Bay and its tributaries year-round or visit its waters as they migrate along the East Coast.

Bay 101

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Bay 101: Wetlands

Wetlands are important wildlife habitat that also help improve water quality downstream

The Chesapeake Bay Watershed

A watershed is an area of land that drains to a particular river, lake, bay or other body of water. Watersheds are sometimes called “basins” or "drainage basins."

We all live in a watershed. Some watersheds, like that of your local stream or creek, are small. Others, like the Chesapeake Bay watershed, are very large. Learn more about the Chesapeake Bay watershed.

The Bay Ecosystem

An ecosystem is a complex set of relationships among living and non-living things. Air, water, soil, sunlight, plants and animals – including humans – make up an ecosystem. Ecosystems can be as tiny as a patch of dirt in your backyard, or as large as the entire Chesapeake Bay watershed.

The Bay Ecosystem

The Chesapeake Bay, the largest estuary in the United States, is an extremely productive and complex ecosystem. The Bay ecosystem consists of the Bay itself, its local rivers and streams, and all the plants and animals it supports. Learn more about the Chesapeake Bay ecosystem.

Critter Of The Month

Loggerhead Turtle
Caretta caretta

Named for its large head and powerful jaw, the loggerhead turtle visits the Chesapeake Bay from May to November to forage and will nest on nearby barrier islands.

Chesapeake History

2014

2014
  • The Chesapeake Executive Council signs the Chesapeake Bay Watershed Agreement, which contains goals and outcomes that will guide conservation and restoration across the watershed. For the first time, the Bay’s headwater states commit to those goals that reach beyond water quality.

2013

2013
  • A federal judge rules that the U.S. Environmental Protection Agency can set pollution limits for the Chesapeake Bay, thus upholding the Total Maximum Daily Load (TMDL) that was challenged in court in 2011.

2012

2012
  • Harris Creek becomes the first target of the oyster restoration goals set forth in the Chesapeake Bay Executive Order: to restore oyster populations in 20 Bay tributaries by 2025. In this Choptank River tributary, existing reefs will be studied, new bars will be built and spat-on-shell will be planted.

2011

2011
  • The U.S. Environmental Protection Agency issues a new Municipal Separate Storm Sewer Permit to the District of Columbia. It is the first of its kind to incorporate green infrastructure into its requirements, setting a national model for stormwater management.

2010

2010
  • Maryland, Virginia and New York ban phosphates in dishwasher detergent to lower phosphorous pollution in local waterways.
  • The U.S. Environmental Protection Agency establishes the Total Maximum Daily Load to limit the amount of pollutants that can enter the Chesapeake Bay.
  • The Bay Program launches ChesapeakeStat to improve communication about restoration goals, progress and funding.

Bay FAQ


Where is the Chesapeake Bay saltiest?


How does salinity change as you move through the Chesapeake Bay?


Are there invasive species in the Chesapeake Bay watershed?


How does air pollution affect Chesapeake Bay health?


How do forest buffers benefit the Chesapeake Bay?


What are benthos?


What is the ideal salinity for eastern oysters?


How many types of grasses grow in the Chesapeake Bay?


What is fish passage?


How does a loss of underwater grasses affect other parts of the Chesapeake Bay?

See more FAQs.

Bay Glossary

Photic zone

The layer of water that sunlight is able to penetrate through and reach plants growing underwater.

Submerged aquatic vegetation (SAV)

The technical term for bay grasses that grow underwater. SAV can improve water quality and provide food and habitat to fish, shellfish and waterfowl.

Fish ladder

A series of ascending pools of running water constructed to allow fish to swim upstream around or over a dam.

Cap load allocations

Based on each tributary’s nutrient and sediment input to the Bay, the total Chesapeake Bay pollution load is divided proportionally to each tributary and jurisdiction. Cap load allocations show where the nutrient and sediment loads will most effectively be reduced to achieve restoration goals.

Clean Water Act

Common name for the Federal Water Pollution Control Act. Its purpose is to “restore and maintain the chemical, physical and biological integrity of the nation’s waters,” whether on public or private land. It authorizes the U.S. Environmental Protection Agency (EPA) to set water quality criteria for states to use to establish water quality standards.

Extant species

A species that is currently in existence (the opposite of extinct). 

Anadromous fish

Fish that spend their adult lives in salt water but must migrate to freshwater tributaries to spawn. For example, Atlantic sturgeon and American shad are both anadromous fish.

Low-impact development (LID)

Innovative stormwater management practices that mimic a site’s pre-development hydrology. LID uses design techniques that reuse runoff and allow it to soak into the soil, helping to protect local water quality.

See more bay terms.

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