-->

Chesapeake Bay

Understanding Sea Level Rise in the Nation's Largest Estuary

Chesapeake Bay Sentinel Site Cooperative

thumbnail of Chesapeake Bay map

View Maryland Sea Grant Map of Sentinel Site
Monitoring Tools in the Bay

Chesapeake Bay Sentinel Site Cooperative researchers are working towards a better understanding of how the nation's largest estuary is changing over time due to rising sea levels. Scientists are collecting data with tide stations and other tools at sentinel sites around the Bay. Through intensive studies and long-term observations at these stations, Cooperative partners are helping to create a clearer picture of sea level and ecological changes in this region to better inform coastal decision-makers about the health of the Bay now and into the future.

"The success of the Chesapeake Bay Sentinel Site Cooperative can be traced to a dedicated group of scientists and managers interested in creating meaningful science syntheses that inform and guide decision-makers throughout the nation's largest estuary," says Sarah Wilkins, who coordinates the Chesapeake Bay Sentinel Site Cooperative as a Sea Grant extension specialist at the University of Maryland. "As a community of practice that shares lessons learned, advancements in the field, and best practices, we are beginning to understand how sea level rise and other environmental changes drive elevation gain and loss across vital Bay marshes."

When you think of sea level rise, you may picture the ocean rising slowly and uniformly around the world, just as water rises when filling a bathtub. But it's not that simple. While it's true that, on average, sea level is rising around the globe, sea level is changing at different rates in different regions on the local level as a result of several interacting processes. Some of these factors include global sea level rise caused by thermal expansion and melting glaciers; sinking of the land (subsidence) caused by groundwater extraction and geological processes; and the influence of oceanic and atmospheric dynamics, such as the El Niño Southern Oscillation.

The Chesapeake Bay—which experiences the highest rate of sea level rise on the Atlantic Coast—is a prime example of local sea level rise variability. In this region of the world, subsidence strongly influences local sea level rise. Long-term data from NOAA tide gauges positioned around the Bay indicate that relative sea levels are rising at 3.4 mm per year, or twice the average global rate of 1.7 mm per year. Over a 30-year period from 1985 to 2015, tide gauges showed rates of sea level rise ranging from 4.8 mm per year in flood-prone Annapolis, Maryland, to 6.3 mm per year at Sewell's Point, Virginia, in the Hampton Roads region.

Scientists take surface elevation table measurements on Deal Island, Maryland.

Ready, SET, go!

Scientists take Surface Elevation Table (SET) measurements on Deal Island, Maryland. The SET is one of many tools used to study the Bay's wetland areas. SETs are mechanical devices permanently installed in wetlands that allow scientists to measure small changes in surface elevation precisely and accurately. The simple tool allows scientists to better understand how coastal marshes are responding to local sea level rise. Image Credit: Kim Hernandez

Over 17 million people live within the bounds of the vast Chesapeake watershed. The estuary and its network of streams, creeks, and rivers hold tremendous ecological, cultural, economic, historic, and recreational value for the region. More than 250 fish and shellfish species use the Bay and tributaries for some portion of their life cycles, including American and hickory shad, river herring, striped bass, eel, weakfish, bluefish, flounder, oysters, and blue crabs. More than 300 migratory bird species can also be found in the watershed. With a better understanding of how sea level changes are affecting the Chesapeake, Cooperative partners are helping communities make informed decisions to keep the Bay healthy and sustainable.

Visit Maryland Sea Grant's website to learn more about this Cooperative, get contact information, and view/download a four-page brochure:

Maryland Sea Grant: Chesapeake Bay Sentinel Site Cooperative

Chesapeake Bay Sentinel Site Cooperative Partners

shadow for text box

See how the Sentinel Site Program is helping address sea level rise impacts in the Northern Gulf of Mexico:

Fostering Oyster Management

See how the Sentinel Site Program is helping to protect cultural and natural resources in Hawaii:

Where High Tech and Tradition Mesh

See how the Sentinel Site Program is helping people adapt to sea level change in San Francisco Bay:

Working Together to Build Resilience
Get Social

Contact Us

One Mission, Diverse Strengths

This map shows the type and number of monitoring stations at six locations around the Bay

Taking the Pulse of the Bay

Infographic design credit: Jenna Clark, Maryland Sea Grant; Infographic text Credit: Sarah Wilkins, Maryland Sea Grant Extension Click/Tap the map for a larger view. This infographic is excerpted from a Maryland Sea Grant brochure.

This map shows the type and number of monitoring instruments (described below) installed at six sentinel sites around the Bay: Chesapeake Bay National Estuarine Research Reserve, Maryland; Chesapeake Bay National Estuarine Research Reserve, Virginia; Smithsonian Environmental Research Center; Paul S. Sarbanes Ecosystem Restoration Project at Poplar Island; Blackwater National Wildlife Refuge; Assateague Island National Seashore; and the Virginia Coast Reserve Long-Term Ecological Research Site.

Chesapeake Bay sentinel sites share a mission to improve planning and management decisions by providing the best possible data derived from local observations. Each sentinel site brings a set of strengths to the sentinel site collaborative network. These include studying the efficacy of restoration approaches, conservation strategies for rare and endangered species, and how marshes respond to experimental manipulations intended to mimic human disturbances, such as warming and increased carbon dioxide.

Monitoring Tools

  • water quality icon

    Water Levels: Sea level rise manifests itself differently along the coast, making it important to obtain local water level information. Water level monitoring stations at each sentinel site continually measure the depth of water, providing a long-term dataset for scientists to use.



  • surface elevation table icon

    Surface Elevation Tables: Surface elevation tables (SETs) are mechanical devices permanently installed in wetlands that allow scientists to measure small changes in surface elevation precisely and accurately. This tool allows scientists to better understand how coastal marshes respond to sea level rise. SETs are commonly used with marker horizons—squares of feldspar clay applied to the surface of the marsh—to track changes in accretion (the accumulation of sediments on the marsh surface over time).

  • vegetation sampling icon

    Vegatation Sampling: Scientists measure plant traits such as height, percent cover, stem density, and biomass within sampling plots to understand how wetland vegetation responds to changing sea levels.



  • water quality icon

    Water Quality: Water quality is a major driver of ecosystem change. At water monitoring stations, researchers and managers monitor parameters such as temperature, total suspended solids, dissolved oxygen, pH, conductivity, chlorophyll, and nitrogen.



  • meteorogolical data icon

    Meteorological Data: Real-time weather stations at each sentinel site measure temperature, precipitation, wind speed, wind direction, relative humidity, and barometric pressure. This vital information helps scientists and managers understand estuarine circulation, plant productivity, and storm frequency and intensity.