Wetlands are natural areas shaped by the presence of water, but they don’t all look the same. Some are permanently saturated, like marshes surrounding ponds or slow-moving streams. Others are only wet during certain seasons, filling briefly after rain or snowmelt. Ecologists classify wetlands by how wet they are, the chemistry of their water, and the types of plants and animals they support.
Wetlands play an essential role in keeping natural and human communities healthy. They provide critical habitat for fish, amphibians, shellfish, insects, birds, and many other wildlife species that depend on shallow water and moist soils. Wetland plants and soils act as natural filters, trapping pollutants, and improving water quality. These ecosystems also help reduce flooding by storing excess water like a sponge during storms and heavy rains.
Delaware Estuary’s Coastal Wetlands
In coastal regions, tidal or coastal wetlands are regularly flooded by the daily rise and fall of water influenced by the moon’s gravitational pull. Moving closer to the coast, water gradually shifts from fresh to brackish and eventually salty. The Delaware Estuary is unique because tidal wetlands extend from its connection with the ocean, where it is saltiest, all the way to its head of tide, where it is fresh. This creates a diverse system of freshwater tidal marshes and salt marshes.
Many bird, fish, and crustaceans live in the estuary’s tidal wetlands. Healthy and expansive tidal marshes also help keep the estuary’s water clean. Tidal wetlands protect shorelines from erosion and storm surges, making them vital for both ecological diversity and community resilience. Tidal wetlands collect and hold a lot of mud, or sediment! They are critical for protecting communities against coastal flooding and trapping carbon.
Just aspeoplerequireregular health check-ups, scientists monitor wetlands over time to understandhow healthy they are. The size and health of tidal wetlands is very important to the overall well beingof the Delaware Estuary. In the Comprehensive Conservation and Management Plan for the Delaware Estuary, wetland loss prevention is a major strategy for ensuring the Estuary’s long-term health.
Monitoring the Delaware Estuary’s Coastal Wetlands
Because coastal wetlands are rather complex to study, the Mid Atlantic Coastal Wetland Assessment (MACWA) was established in 2008 to support research, monitoring, and assessment throughout the region. This ongoing program has been essential in helping scientist understand, preserve, and improve the Estuary’s diverse tidal wetlands.
Coastal Wetlands Are At Risk
Both human activities and natural changes threaten tidal wetlands. Development, like new roads, schools, and housing are often built on or near tidal wetlands. This can disturb and alter the flow of water through the tidal wetlands, leading to impairment. Rising sea levels and strong storms are also submerging and eroding many tidal wetlands. Over time, these pressures have contributed to the loss of about one acre per day, and a decline in wetland health. Wetlands in poor health filter fewer pollutants, capture less carbon, and provide less flood protection compared to those in better health.
Mid-Atlantic Coastal Wetlands Assessment
MACWA
In 2006, the Partnership for the Delaware Estuary (PDE) identified coastal wetlands status and trends as a top priority for understanding the overall environmental health of the watershed. Until then, information about coastal wetland condition and acreage was limited and not consistent among the three states.
In 2007, PDE worked with the Delaware Department of Natural Resources and Environmental Control (DNREC) to design and begin to implement a multi-level program to assess the health and extent of coastal wetlands in a consistent manner across the Delaware Estuary. Then, in 2008, PDE along with the Barnegat Bay Partnership (BBP) expanded this program to areas outside the Delaware Estuary, referring to it as the Mid Atlantic Coastal Wetland Assessment (MACWA). MACWA supports a comprehensive assessment of coastal wetland condition across the Mid Atlantic region. PDE, BBP, and partners such as the Academy of Natural Science of Drexel University have since worked to implement MACWA as a regional strategy, which is continuously updated and strengthened.
The MACWA is a 4-tier monitoring and assessment program envisioned to provide rigorous, comparable data across all tidal wetlands of the Mid Atlantic, especially those in the Delaware Estuary within Delaware, New Jersey, and Pennsylvania, as well as Barnegat Bay in New Jersey. It has become a platform through which research and monitoring is conducted and data are mined for various purposes. The programmatic structure of MACWA generally follows EPA national guidance (U.S. EPA 2001 ) (left figure):
1. Remote Sensing: landscape census surveys of extent and condition
2. Ground Truthing: probabilistic on-the-ground sampling across the study region to assess condition and to ground-truth Tier 1 surveys
3. Intensive Studies: studies to examine specific relationships among condition, function, and stressor impacts
4. Station Monitoring: intensive monitoring of condition and function at a networked array of fixed stations
The Mid Atlantic Coastal Wetlands Assessment program would not be possible without the generous funding and support provided by multiple entities, including the US EPA Region 2, US EPA Region 3, and the US EPA Head Quarters. Additionally, the MACWA team is deeply grateful for our other funders including New Jersey Department of Environmental Protection Coastal Zone, the National Estuary Program, New Jersey Department of Environmental Protection’s Office of Coastal and Land Use Planning, Pennsylvania Coastal Zone Management Program, Delaware Department of Natural Resources and Environmental Control, The Geraldine R. Dodge Foundation, and DuPont Clear into the Future.
For more information and data about wetland research, monitoring, and assessment in the Delaware Estuary, please contact LeeAnn at lhaaf@delawareestuary.org.Reports and QAPPs can be located inPDE’s document library.
