Robert Boone spent two decades fighting to revive “The Forgotten River.” Now, he says, “it’s not forgotten anymore.” (Linda Davidson/THE WASHINGTON POST)

As on so many of his trips on the Anacostia River, Robert Boone’s boat is the only one visible for miles.

He putt-putts in a pontoon south from Bladensburg Waterfront Park, where the Anacostia begins its eight-mile run to the Potomac River at Hains Point.

It is dusk on a sweltering Friday. The river is wide and inviting. Its still water appears as flat and soft as a mattress.

There are no embedded shopping carts to shove out of the way, no phone booth carcasses blocking his path, no crashed Oldsmobile lying sideways in the shallows like a beached dolphin.

In the late 1980s, when Boone first began exploring the Anacostia, he could cross the river stepping on discarded car tires almost without getting his feet wet. He gave the Anacostia a terrible name that stuck: “The Forgotten River.”

Robert Boone at his home in College Park. He founded the Anacostia Watershed Society in 1989. (Linda Davidson/THE WASHINGTON POST)

He spent the next two decades on a mission to revive the river — an effort so successful that by the time he retired two years ago from the nonprofit Anacostia Watershed Society he had co-founded, he had to take back his own words: “It’s not forgotten anymore.”

Boone learned to love the water from his father, who frequently took him boating on the Pamlico Sound when he was growing up near Burlington, N.C.

But he became an environmentalist almost by chance. First, there were stints as a soldier, a college teacher, a macrobiotic restaurateur, a global traveler and a carpenter. By the age of 47, he was living in the District and in search of a sense of purpose.

“I felt like, you know, my hair was beginning to gray here and there. I wanted to do something. I hadn’t made a mark. I wanted to do something with my life.”

About that time, he saw a story in The Washington Post. The Interstate Commission on the Potomac River Basin was looking for someone who could walk into classrooms or boardrooms and get people stoked about the Anacostia River.

When he took the job, few people cared that the river had once caught fire or that it was considered one of the most polluted urban waterways in the nation, Boone says.

Boone forced them to care by creating the Anacostia Watershed Society in 1989. As some recall, he had personalities akin to those of Dr. Jekyll and Mr. Hyde: He could be charming, or he could be intimidating.

“I remember him sitting in my office explaining combined sewer overflow in a way that I got it,” says Mardell Moffett, associate director of the Morris & Gwendolyn Cafritz Foundation, which has donated money to AWS for nearly two decades.

During storms, the city’s antiquated sewer system can’t handle both runoff from heavy rains and the stuff that’s flushed down the drain, so raw sewage is dumped in the river, about 2 billion gallons per year.

After rains, the river’s count of fecal coliform — bacteria from human waste — is often 500 times what’s safe for swimming. Boone took Moffett out on the Anacostia and showed her.

“It’s really astonishing to go out on the river after a rain, astonishing in a bad way,” she says.

Boone pressed to change that.

“Robert was really the first one who came to our attention who really cared,” Moffett says. “He said it would be livable and fishable. He has so much charisma and so much passion. He was not going to let anyone tell him no.”

That included people in the city government who didn’t share his sense of urgency.

“You’re just a worthless bureaucrat!” one official recalls him shouting during a meeting about more funding and pollution regulations for the river.

Boone angered some. “He was feisty. It was good,” says Patricia Gladding, the AWS director of operations. “The whole organization was just Robert for a long time.”

The work involved plenty of firsthand observation and exercise. Boone paddled a canoe or steered a boat across the river at least five days a week. For a long stretch in the mid-to-late 1990s, he paddled more than 100 miles from the Anacostia to the Chesapeake Bay each year.

“Boy, I put in some time,” Boone says. “I jumped out of bed eager to work every day. I worked 8 o’clock to 8 o’clock some days.”

Now, he visits the river only about once a month, leaving the still-beleaguered Anacostia without its most visible local champion.

But his impact lives on. The annual Anacostia clean up Boone founded in 1989 now involves nearly 30 groups. AWS volunteers alone have removed nearly a thousand tons of trash. Former President Clinton presented him with the President’s Volunteer Service Award.

And the river itself bears testament to his work.

As Boone’s pontoon boat approaches Hickey Run near the National Arboretum and Kenilworth Park and Aquatic Gardens, the city and its noise slip away.

The water, calm under a canopy of leaves, seems as smooth and green as olive oil. Boone throws up his hand suddenly, pointing at a bird soaring near emerald treetops, and shouts, “There’s a fish hawk!”

The blue sky has streaks of violet. Barn swallows dip low for a good look at the funny-looking square boat, then rush to nests under a bridge where their chicks wail for food. Aside from the chirping, the Anacostia is serene.

“It’s a remembered river,” he says. “It’s a river on the mend.”