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Harbor Wetland at the National Aquarium
Hundreds of years ago, Baltimore’s coastline was teeming with life. The Inner Harbor was a tidal salt marsh filled with thousands of native marsh grasses, shrubs, and wildlife.
Rain and melted snow were filtered through its soil and released into the Patapsco River before traveling into the Chesapeake Bay and Atlantic Ocean, keeping the waterways clean and healthy.
Since the 18th century, Baltimore has developed into a bustling port city. Today, much of the coastline has been developed with buildings, sidewalks, and roads replacing forests and native marsh habitat. The rain and snow melt are now whisked away across asphalt roads and concrete sidewalks, picking up chemicals, waste, and non-biodegradable materials before entering storm drains and releasing into the harbor.
The runoff from city streets and industrial sites can impact water pH in the Chesapeake Bay, contribute to the nutrient pollution that fuels algal and bacterial growth and lowers dissolved oxygen levels, degrade fish and wildlife habitat, and impact outdoor recreation for community members.
A Better Baltimore: the Harbor Wetland Project
Prioritizing the conservation and restoration of Baltimore’s Inner Harbor, NWF’s Maryland affiliate, the National Aquarium, began construction on their Harbor Wetland exhibit in Fall of 2023.
This recently completed 10,000-square-foot floating wetland features more than 32,000 native shrubs and marsh grasses, restoring an essential habitat for wildlife and filtering pollutants from the water.
Among the various flora found in this working wetland, one of the most important species is cordgrass, which absorbs carbon and provides essential wildlife habitat. Cordgrass in salt marsh ecosystems, like those originally found in the Inner Harbor, can withstand being submerged at high tide and exposed during low tide conditions. The algae that grows on cordgrass stems is a favorite food source of mud crabs and small juvenile fish. The thick cordgrass stems provide protection to wildlife like young blue crabs.
These grasses and other native plants grow hydroponically within the Harbor Wetland, their roots uptaking nutrients directly from the water, removing excess nitrogen from polluted stormwater runoff and sewage which harm the entire ecosystem.
The project was designed to be far more than a floating green space exhibit, but a functional wetland that replicates the conditions and functions of a natural tidal marsh. To accomplish this, compressed air from ceramic airstones at the bottom of the custom, six foot airlift pipes circulates water through the man-made channel (pictured below).
Additionally, bubbles from this process release oxygen into the surrounding water, benefiting wildlife by raising dissolved oxygen levels.
Since being installed in the Inner Harbor, Harbor Wetland has already seen the return of fish, crabs, birds, muskrats, otters, American eels, night herons, and essential microorganisms that lead to a self-sustaining habitat.
Across the National Wildlife Federation, our Affiliates are leaders in conservation and restoration of natural ecosystems, advocating for environmental protections, and educating and empowering their communities. Through their work to combat climate change, save wildlife and habitats, and stop plastic pollution, the National Aquarium is a leader in these issues in Maryland and nationally.
The Harbor Wetland at the National Aquarium is now open to the public and free to visit. To learn more, visit aqua.org.
