Protecting the Chesapeake Bay, One Stream at a Time

Stream restoration projects like Cattail Creek offer multifaceted benefits to watersheds and ecosystems

The stream restoration at Cattail Creek uses rocks and plants to reinforce the stream channel. As their roots take hold, plants can help maintain the structure for the long term, DNR officials say. Photo by Joe Zimmermann/DNR

To Bob Royer, the heron that was stalking in the shallow water around a bend in Cattail Creek was a sign of promise.

For one thing, it meant there were fish. But together with the red-winged blackbirds overhead, the buzzing dragonflies, and the water celery that rippled in the stream’s current, the gangly waterbird looking for lunch was evidence of a natural system that was back to work.

“All it takes is little areas of reworking the landscape, and look what it wanted to be,” said Royer, the president of the Berrywood Community Association Environmental Committee. “It wanted to be a wetland.”

Cattail Creek is the site of a stream restoration project, now complete for five years. Maryland Department of Natural Resources officials point to the project as an example of the benefits of stream restorations, both locally and to the Chesapeake Bay watershed as a whole.

As impermeable surfaces increase across the state, stormwater is often channeled into streams at a heavier quantity, causing erosion as well as the buildup of pollutants that aren’t absorbed in the streambed.

In the past few decades, Cattail Creek had become degraded by excessive stormwater runoff from developments and the nearby Route 2. After storms, the stream would run thick and muddy.

Now, since the 2019 completion of the restoration, the stream is clear and controlled, even the day after a big rainstorm.

“The difference between what this looks like now and before is somewhat indescribable,” said Claudia Donegan, the director of DNR’s Center for Habitat Restoration and Conservation.

To get to that point, Underwood & Associates, a landscape architecture and construction company, put six stone weirs into the stream bed to provide structure and slow the water. Residents and the Berrywood Community Association pushed for the project and volunteered with plantings, cleanup, and monitoring at the site.

The restoration received $745,000 from DNR’s Chesapeake and Atlantic Coastal Bays Trust Fund, which awards funding to non-point source pollution reduction projects.

Officials view stream restoration as an important way to divert sediment and nutrient pollution from the Chesapeake Bay. Most of Maryland’s streams eventually flow into the Bay, and they carry with them runoff from urban developments and agricultural fields that are laden with excessive levels of nitrogen, phosphorus, and other materials that contaminate habitats there.

Stream restoration projects follow a variety of techniques and have a range of goals, but these efforts generally aim to promote absorption of nutrients and the retention of sediments in addition to slowing and cooling off water. Other objectives for restoration projects include reducing erosion, protecting infrastructure, reconnecting areas of the floodplain, and reestablishing habitat.

At times, stream restorations have provoked controversy, with critics suggesting projects are ineffective, expensive, or destructive to existing natural areas by removing trees. DNR officials said each stream restoration site that receives funding from the Trust Fund is carefully selected for specific benefits and are monitored after completion. Landscape construction companies have begun to shift away from tree removals at sites as well, and many projects seek to have multiple benefits for the local environment in addition to a focus on climate resiliency.

While many other restoration projects are initially focused on curtailing pollutants, Donegan said that projects are most successful when they can address multiple factors to increase the health of the stream and surrounding environment, as the Cattail Creek project has done.

“What’s great to really achieve is this multi-system recovery, all the way down to these insects and these birds,” she said. “We’re trying to do some nitrogen and phosphorus uptake but this is a process-based stream restoration project that’s multifaceted in terms of ecological recovery.”

As Royer walked along the 675-foot regenerative stream channel of Cattail Creek, he listed the species that have returned to the area since the restoration: muskrats, beavers, wood ducks, Baltimore orioles—and even yellow perch, which anglers used to target in this stream in the 1970s before they disappeared from the area. Now, the creek provides a passageway for fish straight from the Magothy River, and once they get through here they have a lot of area upstream they can travel, he said.

Between 2010 and 2023, DNR’s Chesapeake and Atlantic Coastal Bays Trust Fund helped to fund the restoration of 315,000 linear feet of streams in the state, said Dana Reiss, a DNR senior program director who manages the Trust Fund.

Gabe Cohee, bay restoration officer with the department, said stream restoration projects are one part of the state’s shift in its Bay restoration strategy, which calls for a focus on water quality improvement projects in specific areas with the most potential to improve wildlife habitat and help communities adapt to climate change.

While Bay-wide restoration is still the ultimate goal, Cohee said attention to local efforts, like stream restorations in a neighborhood, can bring environmental issues right to people’s backyards and helps get more communities involved.

“When we think about watershed restoration only in terms of nutrient and sediment reduction, that doesn’t always speak to everyone,” Cohee said. “We want to look at more of those shallow water habitats all through the tributaries of the Bay and shift our impacts to local streams and the interface of where water and land meet.”

Stream restorations that have provoked more controversy often ignored that community element, Donegan said. Some projects are rapidly permitted in order to meet total maximum daily load, or TMDL, credits, she said, and don’t take into account how the effort will affect the larger ecosystem or the surrounding area.

When assessing stream restorations to support through the Trust Fund, Reiss said the department looks for projects that take community involvement seriously, making sure that residents in the area near the stream are on board by holding community meetings and working with local groups. 

Successful stream restoration projects are also focused on ecological co-benefits—the habitat and environmental gains aside from nutrient reduction—and Reiss said the Trust Fund asks any applicant for funding to justify their designs against possible alternatives. This ensures there is a reason behind any intervention they make in the stream environment.

But for everything a stream restoration project can do, Donegan said the best thing for streams would be to prevent excessive runoff from entering them in the first place. This is where stormwater mitigation efforts come in. Practices like bioretention ponds,  green roofs, infiltration facilities, and permeable pavement are intended to ease the amount of runoff that continued development channels into streams.

A combination of stream restoration and stormwater mitigation would be ideal for most areas, she said. And the ability for individual homeowners and developers to make improvements for stormwater retention is another way for a community to have direct involvement in the ecosystem around them.

Where Cattail Creek runs into the Magothy River, there’s now a living shoreline, where plants have rooted in to take place of a concrete bulkhead. Organizers say this creates habitat for fish while also reinforcing the land and creating a safer shoreline for residents. Photo by Joe Zimmermann/DNR

This community aspect is important in Cattail Creek. Royer, who lives in the adjacent neighborhood, remembered his children playing in the stream when they grew up, and is happy to see kids returning to the area now.

This restored stretch of the Cattail Creek flows out directly into the Magothy River, and the organizers of the restoration decided to complete the project with a living shoreline to replace the concrete bulkhead that abutted the river.

Now, grasses planted along the shoreline—like the plants along the stream—will fortify the structure of the land for generations to come, Donegan said. It also makes the area a better habitat for fish and safer for residents.

“This is a big part of the ecosystem and making it a complete picture” Donegan said. “And I really think that this type of approach from land to water is really good for humans too.”

By Joe Zimmermann, science writer with the Maryland Department of Natural Resources.