How Scientists Are Cleaning Up Rivers Using Grasses and Oysters

The story is part of the Climate desk collaboration.

Two divers from the US Environmental Protection Agency hovered over a patch of silt 10 feet below the surface of the Delaware River in New Jersey. With less than two feet of visibility in the estuary, they were moving a species important to the ecology. A diver holding a flashlight and a camera captured a shaky clip of the thin, ribbon-like blades bending with the current.

The Center for aquatic sciences at Adventure Aquarium in Camden had nurtured these plants for months in tanks, from winter buds to mature grasses some 24 inches long.

He said it was nerve-racking to release the grasses into the wild where they could be eaten by a duck. That's life, that's what it is.

The first planting of a new restoration project was led by Upstream Alliance, a nonprofit focused on public access, clean water, and coastal resilience in the Delaware, Hudson, and Chesapeake Watersheds. The EPA's Mid-Atlantic team and the National Fish and Wildlife Foundation are supporting the alliance's efforts to reestablish wild celery grass in the estuary. Some 15 million people rely on the Delaware River to get their drinking water.

In the 50 years since the passage of the Clean Water Act, urban waterways are showing signs of life. The waters are often not accessible to the communities that reside around them. Scientists, nonprofits, academic institutions, and state agencies are focusing on organisms like bivalves and aquatic plants to help nature restore fragile environments, improve water quality, and increase resilience.

Bivalves and aquatic vegetation allow more light to enter the water. They have the ability to absorb food and make it more available to other organisms. Habitat for small fish, crabs, and other bottom-dwellers can be found in the underwater plant meadow. Bivalve beds act as a foundation for benthic habitat, holding in place the debris from the sea.

The science director at the Partnership for the Delaware Estuary says that plants and animals are naturally resilient and can be rebuilt. Water quality benefits, fish and wildlife habitat, as well as better access for people are some of the benefits.