Last year, organizers distributed bags and gloves at 633 cleanup sites. (Alice Ferguson Foundation photo) Last year, organizers distributed bags and gloves at 633 cleanup sites. (Alice Ferguson Foundation photo)

Even the Potomac could use a little spring cleaning.

Each year, March rains wash litter from city streets into storm drains and from there into streams, so debris eventually winds up along the Potomac river’s shores. The problem is compounded by litterbugs who drop trash near the river.

To combat the mess, each year during the first weekend of April, thousands of volunteers take part in the annual Potomac River Watershed Cleanup, a gargantuan trash pick-up along the banks of the river and its tributaries.

The cleanup, the largest regional event of its kind, spans Maryland, Virginia, West Virginia and the District. It’s spearheaded by the Alice Ferguson Foundation, an Accokeek, Md.-based nonprofit dedicated to keeping the Potomac clean. This year’s all-volunteer trash collection takes place Saturday.

Last year, nearly 15,000 gloved volunteers at 633 sites along the river plucked rogue bottles and snack food wrappers from muddy banks. Organizers say the haul yielded 312 tons of trash and debris, including 193,800 beverage containers, 27,400 cigarettes, 27,200 plastic bags, and 1,314 tires — not to mention shopping carts, golf balls, car batteries, mattresses and the occasional appliance.

The tradition kicked off in 1989 with a small cleanup at a single site, the foundation’s Hard Bargain Farm Environmental Center at Piscataway National Park.

“Students who had been coming to the farm for nature hikes kept seeing this trash, and asked, ‘What are you going to do about it?’” says Alena Rosen of the Alice Ferguson Foundation. The cleanup effort snowballed from there.

Now, with thousands of volunteers at hundreds of sites, each site has a leader trained in dealing with biohazards — like syringes, razor blades or medical waste — and in getting private property owners’ permission to clean. Site leaders distribute gloves and bags, and make sure bagged debris gets to landfills and recycling centers at the day’s end.

One of those coordinators, Jim Heins, 80, helps organize around 200 volunteers each year along the 185-mile C & O Canal National Park. Heins says much of the trash comes from upstream — as far away as Pennsylvania — as well as from litterbug park-goers.

“They just pitch it on the ground,” Heins says, referring to the wrappers, bottles, spent fishing supplies and even neatly tied bags of dog poop that end up around park.

Heins has also found some oddities, such as the century-old upright typewriter and the abandoned safe (which a lock-picking friend revealed was empty). His volunteers have discovered strollers, computers, smart phones, parking signs, orange cones, lawn chairs and a river-ravaged bicycle.

Volunteers find the process pretty satisfying. “What’s great about a cleanup is that you see a tangible result — you see progress,” Rosen says.

And there are important results volunteers can’t see: The once-ocean-bound litter they pick up will no longer be likely to harm wildlife or become part of an ocean garbage patch, nor will it pollute the Washington region’s major water supply (which goes through a filtering/treatment process before it reaches our taps). Tangible or not, that’s good progress.

Saturday, multiple locations, 301-292-5665,