They call him the riverkeeper — protector of New Haven’s waters, crusader against illegally dumped trash.

Despite the title’s mystique, the riverkeeper is not a man with a primeval key hung around his neck that unlocks waterways. The riverkeeper is Peter Davis — a 46-year-old man who, on this particular Saturday morning, is cruising through Fair Haven in his shamrock-green Ford pickup, the back brimming with his finds: a couch, a computer, tires, and a flaming red metallic door from an Ozzy Osbourne van.

“People say I’m a little wacky,” Davis says. “I guess I am. But it’s almost like a religion, you know what I’m saying?”

The object of his faith: New Haven’s three rivers — the Quinnipiac, the Mill and the West — all of which pour into Long Island Sound.

For much of the year, Davis spends eight hours a day driving a regular route that covers about 40 of the city’s most popular spots for illegal dumping, from parks to dead-end streets. He starts in East Rock, swings through Fair Haven, and then loops around to West Rock.

Davis’ job is to preserve the city’s rivers, but he doesn’t get his feet wet on a day-to-day basis. He spent his first years on the job cleaning out the rivers. Now he is focused on the trash beside them.

“Anything that’s dumped by the river ends up in the river,” Davis said. “I guarantee it.”

From May to November, Davis also runs the only free canoeing program in Connecticut, with 14 canoes, 15 kayaks and 12 launching points along the city’s rivers. Last year about 3,000 people of all ages participated, traveling from cities and towns throughout Greater New Haven.

Davis’ wallet is fat with the receipts he collects each time he has his truck weighed at the city’s transfer station. This morning, the loaded truck weighs in at just under 2,980 pounds.

In his 15 years on the job, he has collected a total of 4 million pounds.

“If you take a year off, you’re going to find more couches, refrigerators and mattresses in the river again,” Davis said. “You’ve got to maintain them. You’ve got to maintain them.”

To aid him in his work, Davis has a part-time helper: David Burgess, a 34-year-old autistic man whom Davis met 20 years ago when he worked for Benhaven, a nonprofit group that helps the mentally disabled. Burgess is always accompanied by his Benhaven job coach, Zaid Qawiyy, who has only one eye but also helps out.

Davis knows of only one other riverkeeper, who oversees the Hudson River.

As he drives down a quiet street in Fair Haven, Davis spots trash on the side of the road and gets out of his truck to clean it up. A woman hollers at him from a second-floor window. She doesn’t know about the riverkeeper — what does he think he’s doing?

Smiling, Davis looks up and explains his job. The woman tells him about the people who drive by and toss their trash out of their cars and onto the street.

“I’m sorry you have to live like this,” Davis says.

“I’m sorry, too,” she says, leaning out of the window of the building, where she has a filing job.

The woman, named Lori, begins a litany of complaints about what she sees near the building. She comes down to point out the dank corner behind the building where she says a homeless man recently lived for months.

She says she finds used needles and encounters prostitutes in cars next to the building.

“I come out here and clean it up, but it keeps getting dirtier,” Lori says.

She sits in front of the building, scanning the street for trash. Visible down the street are the Quinnipiac River and the Quinnipiac Bridge. As Lori explains that she has finally moved out of Fair Haven and into the Hill, she stands up and walks into the middle of the street, stoops over and picks up a knife. With a fling, she tosses it into the parking lot across the street and returns to her perch on the front steps.

The street trash bothers her, but the environment is a secondary concern.

“I have no comment about that [trash] because the vicinity of Fair Haven is very dirty itself,” Lori says. “Start with the drug dealers and prostitutes. Start cleaning that up.”

But Davis said cleaning up trash is an important step in improving communities.

He and officials from the state Department of Environmental Protection said much of the illegal dumping is concentrated in blighted areas. In New Haven, trash often piles up in West Rock, the Hill and Fair Haven.

Davis himself grew up in the Hill in the Church Street South housing projects. The rivers were “foreign” to him until he began volunteering with park cleanups.

“And then I was looking at the rivers — what about the rivers?” Davis said. “And I was told they’re not really part of the system. So I said, what the heck, maybe I’ll start doing that.

“And I had no idea it would end up like this. I had no plan.”

Davis cleans up each spot every day only to find more trash dumped there typically within 24 hours. And the amount of trash he is finding has surged recently. Davis collected 40,000 pounds of trash in October, then 65,000 in November, and 70,000 in December.

“It gets a little depressing, but on the other hand when you do it, you’re showing the public that there’s a response time that’s quick,” Davis said. “If you leave it there, it’ll become a mountain of trash.”

Davis said the rivers are also a source of food for some residents who fish to cut back on grocery bills.

“It’s cheaper to fish than to go to Stop & Shop,” Davis said.

He also has a rigorous schedule of visiting neighborhood schools and teaching children about the city’s rivers. One boy recently left a message on his voice mail tipping him off to a spot that needed to be cleaned. Davis himself has two sons, 4 and 6 years old, who often help him scavenge.

“The river is his life,” said Jackie Pernell, a DEP case investigator who has worked closely with Davis since the riverkeeper began his job. “Nothing gets by him. Nothing — I mean nothing.”

As Davis’ thin frame hunches over the steering wheel, his eyes dart around looking for trash. He says he plans to stay with the job he loves “until I get called to the big river in the sky — with those guys, to stay on top of things.”