Wetlands Overview

Wetland Science and MACWA



Glossary of Terms

Wetlands Overview

Wetlands are habitats with a unique relationship with water. Wetlands can be saturated with water, like those fringing ponds, or they can simply have moisture-laden soils. Ecologists use many terms to categorize different types of wetlands based on their wetness and what plants grow there, such as marshes, bogs, fens, or swamps.

Wetlands are important because they provide food and homes to fish, amphibians, shellfish, insects, birds and other animals. They also clean our water by filtering out pollutants and provide flood protection for our communities by acting as natural sponges.

Delaware Estuary's Tidal Wetlands

Delaware Estuary's Tidal Wetlands

Tidal wetlands are habitats that are regularly flooded by tides— or the rising and falling of water levels associated with the moon’s gravitational force. The Delaware Estuary is unique because it has tidal wetlands from its connection with the ocean all the way to its head of tide. This expanse has many types of tidal wetlands, such as freshwater tidal marshes, salt marshes, and those in between.

These tidal wetlands capture lots of mud! You can think of tidal wetlands as a network of habitat that connects from where we live to the ocean.

Tidal wetlands are important places. They are critical in protecting communities against coastal flooding. They also combat climate change impacts by trapping carbon.

Lots of fish, birds, and crustaceans call the Delaware Estuary’s tidal wetlands home. Many other animals simply use the area to migrate, like the endangered red knot, or to spawn, like horseshoe crabs. Healthy and expansive tidal marshes also help keep the Estuary’s water clean.

Tidal Wetlands Are At Risk

Human and environmental influences threaten tidal wetlands. New roads, schools, and housing developments are often built on or near tidal wetlands as our towns grow. This can disturb the flow of water through the tidal wetlands, leading to impairment. Rising sea levels and storms are also submerging and eroding many tidal wetlands. These threats acting over time has led to a loss of about one acre per day, and a decrease in the health of tidal wetlands. Wetlands in poor health filter fewer pollutants, capture less carbon, and provide less flood protection compared to those in better health.

Why Monitor Tidal Wetlands?

Just like humans need regular health check-ups, scientists monitor  wetlands over time to see how healthy they are. The health and size of tidal wetlands is very important to the overall health of 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. Tidal wetlands, however, can be rather complex to study. In 2008, the Mid Atlantic Coastal Wetland Assessment (MACWA) was founded to help support research, monitoring, and assessment of tidal wetlands in the region. This program has been pivotal for ongoing work to understand, preserve, and improve the Estuary’s diverse array of tidal wetlands.