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When Dave Eckert asked Jim Fowler to be the on-screen host of his documentary film Four Mile Run: Reviving an Urban Stream, Fowler—a former local with a national reputation as a naturalist—was immediately drawn by the opportunity to express his environmental philosophy.

“How we treat the Earth basically affects our social welfare and our national security,” Fowler says in a burly voice—appropriate for the guy who nabbed lions and wrestled crocodiles on Mutual of Omaha’s Wild Kingdom from 1963 to 1989. “I was impressed that here’s a guy that’s interested enough in Four Mile Run to want to do something.”

Working on the project gave Fowler—now wildlife correspondent for NBC’s Today show—a reason to return to his boyhood home in the city of Falls Church, Va., for only the second time since 1946. Growing up along Four Mile Run, he says, he developed many skills he later used in his professional life.

“When I was probably 10 years old,” Fowler says, “I used to take a bamboo pole and put a red piece of cloth on the end of it to catch frogs. Bullfrogs would jump and grab the color red. Later on, when I was with the Indians down in the Amazon, they had a similar system, but they’d never seen taking a red cloth and catching things that way.”

Although Fowler’s “old homestead” itself stands much as he left it, it’s now part of a neighborhood of single-family homes that surrounds Arlington’s Benjamin Banneker Park and Falls Church’s Isaac Crossman Park, near the East Falls Church Metro station. Four Mile Run meanders through these adjacent parks on its way from Tysons Corner to Reagan National Airport, where it joins the Potomac River.

As National Public Radio’s Frank Stasio narrates in the film, Four Mile Run formed millenniums ago, when geological upheavals raised the ridge of rock that is now Tysons Corner, where it has its headwaters. The area became home to buffalo, bear, and beaver, then to various native tribes, and finally to European settlers, who eventually dominated the stream with railroads, bridges, and roads.

And that’s just in Part 1. Eckert divided the film, which he wrote, produced, and directed, into four separate segments to be more easily presentable on cable TV, at conferences, and at public meetings. The other three parts present “current-day hidden treasures,” outline pollution problems, and encourage the revival of the stream to a wild state.

The documentary is just the latest chapter in Eckert’s 11-year effort to focus attention on Four Mile Run. In 1990, he founded the City Streams Task Force (from within the Village Preservation and Improvement Society, a nonprofit citizen-volunteer organization in the city of Falls Church), which a year later kicked off the Urban Forest Stream Valley Demonstration Project in Crossman Park. The group tried to fight development projects along the stream in both Falls Church and Arlington. “We lost every battle, mind you,” Eckert says. “[The task force] wasn’t able to stop development—even with the laws [against it], because laws were broken. That led me to want to make this film.”

Eckert, a tireless city booster, likes to talk about the 28 authorities—naturalists, geologists, plant experts, residents, and politicians—he assembled to tell the stream’s story. Fowler, on the other hand, would rather discuss the global impact of Eckert’s local efforts. “The quicker we humans learn that saving open space and wildlife is critical to our welfare and quality of life,” he says, “maybe we’ll start thinking of doing something about it. That film really has the potential to bring it more home locally why it is important.” —Jeff Bagato

Four Mile Run: Reviving an Urban Stream premieres on Wednesday, Oct. 24, at the State Theatre in Falls Church, Va. Doors open at 6:30 p.m. A concert by Andrew Acosta and the New Old Time Pickers will precede the screening. For more information, call (703) 237-0300.