A trash build-up by the Anacostia River. (Jabin Botsford/The Washington Post)

If the FBI moves its headquarters to Greenbelt it could have a profound effect on a tributary to the Anacostia River, a waterway federal and local officials have spent decades and millions of dollars trying to restore.

But it may not be a negative effect.

The 82-acre site in Greenbelt — one of three final locations being considered for a new FBI campus — is currently a parking lot for the Greenbelt Metro station, adjacent to a series of wetlands and Indian Creek, a polluted tributary of the Anacostia River.

Nearby Narragansett Run, which also ultimately feeds the Anacostia, is also badly in need of restoration, having never recovered from sediment and pollution dumped there from mining operations.

The existing Metro facilities, built in 1993 where some wetlands previously existed, have done to little to improve what’s sometimes referred to as the area’s “forgotten river.”

Rain falling on the 3,700-space surface parking lot for the station, along with the pavement for a kiss-and-ride lot and bus depot, mostly runs into the nearby tributaries, adding pollutants and toxins. A wetland constructed to mitigate the Metro construction fizzled when plant and wildlife failed to take hold, leaving a mostly muddy pit.

Whether or not the FBI relocates to Greenbelt, which may be decided next year, the prospect of adding 4 million square feet or more of new buildings on the site prompted consternation among some environmentalists and officials from the City of Greenbelt.

But it also attracted officials from the Environmental Protection Agency, who see the project as a high-profile opportunity to model environmentally sustainable development and reducing storm water pollution from development near waterways.

In the massive Greenbelt complex proposed by Renard Development, the FBI would occupy the five lower buildings. (Courtesy Renard Development/Gensler)
In the massive Greenbelt complex proposed by Renard Development, the FBI would occupy the five lower buildings. (Courtesy Renard Development/Gensler)

EPA officials joined the project’s developer, Garth E. Beall of Renard Development, along with engineers, environmentalists and local officials Tuesday at the University of Maryland to identify how the project could not only do as little harm as possible to its surroundings but possibly improve them.

“Historically storm water infrastructure hasn’t had the same level of attention, for a number of reasons, as drinking water and waste water,” said Dominique Lueckenhoff, a deputy director in the EPA’s water protection division. “It’s something that people don’t tend to really see. It’s not like the big building that we see that’s the water treatment plant.”

[Related: How a Greenbelt attorney became an unlikely frontrunner to win the FBI headquarters]

Storm water runoff is typically prevented by replacing impervious surfaces (such as concrete) with those that can absorb heavy rains without allowing run-off, such as rain gardens and so-called “green” roofs, or by installing collection facilities like underground cisterns that allow the water to be treated or filtered before it is released. Few of those options were employed in the past.

“I think we all have to acknowledge that we’ve made a lot of mistakes in how we’ve developed the region…I think we have to learn from those mistakes and not repeat them as we move forward,” said Jeff Corbin, EPA senior adviser for the Chesapeake Bay and Anacostia River.

At this point, Corbin said, “the watershed has its problems. We all know that. It’s one of the most urbanized watersheds in the nation. But if we achieve what we want to with this project, it’s going to have ramifications everywhere.”

According to the development guidelines put forth by the federal government, whether the new FBI campus is in Greenbelt, Landover or Springfield it will be built to the “gold” standard under the LEED green buildings system.

[Related: Fairfax and Prince George’s compete for FBI headquarters]

Beall, whose company has been trying to develop the Greenbelt site for more than a decade, said that with his $2 billion project he plans to take things much further, though it will not be cheap.

Already his company has built a 4.3-acre wetland on the south end of the property at a cost of about $800,000.

He said he has budgeted $6 million into the project to build an underground system of storm water management canisters developed by an Ohio-based company, Contech Engineered Solutions.

Beall also said the forum, which included clean water champions such as Philippe Cousteau, Jr., grandson of the famous underwater explorer Jacques Cousteau, would help him identify other technology opportunities.

It’s possible that Metro would be willing to foot some of the cost to mitigate the effects of a planned new parking garage.

“We’re at a crossroads of really working on the project and what I am trying to do is get the best people and the best minds,” Beall said.

Who knows if the Anacostia will be clean enough to swim in a decade from now, a goal set by some cleanup advocates. But Beall said he had “absolutely no doubt” that his development will be better for the river than what’s there now.

Follow Jonathan O’Connell on Twitter: @oconnellpostbiz