Wetlands Overview

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Wetlands Overview

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. 

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. 

Why Monitor Tidal Wetlands?

Just as people require regular health check-ups, scientists monitor wetlands over time to understand how healthy they are. The size and health of tidal wetlands is very important to the overall well being 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.

 

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. 

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