Andrew Macdonald, a former vice mayor of the City of Alexandria, is chair of the Environmental Council of Alexandria Virginia.

Alexandria officials say they want to “restore” three streams to meet the city’s federally mandated Clean Water Act targets for specific pollutants such as nitrogen, phosphorus and sediment.

That’s worrisome.

Proponents of stream restoration claim these projects are a cost-effective way for local governments such as Alexandria’s to obtain regulatory credits for removing pollutants flowing into the Chesapeake Bay and preventing storm runoff from continuing to degrade stream channels. Opponents argue that stream-restoration projects do not improve water quality, especially in urban streams, and that they destroy important natural habitat along streams, including Taylor Run, Strawberry Run and Lucky Run in Alexandria.

But what does science say?

The Environmental Council of Alexandria has spent more than a year studying the potential environmental effects and benefits of the city’s proposed restoration of Taylor Run in Chinquapin Park, near T.C. Williams High School.

The Taylor Run stream-restoration project, as with all such projects, involves the complete removal of mature native vegetation, including trees, along the banks of streams so that the stream channel can be restored to a supposedly more natural condition. Riparian forests such as those found along Taylor Run keep pollutants, including phosphorus and nitrogen, out of the bay by recycling them naturally. Trees also improve water quality in these streams by reducing stream bank erosion. These forests provide critical habitat for migratory birds, native plants and other wild creatures in urban areas. They also help reduce urban flooding, which is a growing problem in the D.C. region because we have paved over so many of our watersheds.

The goal should be to preserve and protect these natural ecosystems, not replant them.

Our study shows that these projects will not stop stream erosion and will result in even more sediment pollution. The water-quality benefits of these projects are largely unproven and unreliable. There is no evidence that stream restoration can transform degraded urban stream channels into pristine natural ones similar to those that might have existed a century or so ago. Storm-water runoff is the real problem, and this sort of restoration is little more than a Band-Aid.

What should we be doing?

Cities need to capture and control much more of the storm water that runs off paved surfaces using green infrastructure so that the runoff is released slowly into urban streams. This is a proven way to reduce stormwater erosion and pollution, and help urban stream channels heal naturally, too.

Although the Alexandria City Council approved two stream-restoration grant applications to the Virginia Stormwater Local Assistance Fund for Taylor Run and Strawberry Run in 2018, the city made it clear that the projects could be halted if the community found then unsuitable. It is clear that these projects will not improve the bay’s water quality or the health of these streams.

The mayor and the current council should rescind these grants and look for alternative ways to reduce storm-water pollutants. There is clearly a place for sensitive and limited stream restoration, but the emphasis should be on controlling storm-water runoff before it harms these streams and the bay. It is disturbing that state funding agencies, including the Virginia Department of Environmental Quality, still support these environmentally flawed projects.

We should stop relying on these stream-restoration projects to help us meet local and regional pollution reduction targets for the Chesapeake Bay. They don’t work. If we want to help the bay, we must manage stormwater before it reaches these streams. The native flora and fauna that are still found naturally along urban streams and the parks they flow through should be protected, not bulldozed.

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