A visitor to Scott's Run Nature Preserve in McLean, Va. is seen near a waterfall last week. Swimming and wading in the water near the falls is not allowed. Littering and underage drinking have also been issues in the park. (Matt McClain/The Washington Post)

With a waterfall and spectacular views of the Potomac River, the Scott’s Run Nature Preserve in Northern Virginia is a magnet for hikers and anyone else looking to blow off steam during the long Memorial Day weekend.

For Fairfax County, that means dealing with a growing problem that has turned away some parkgoers and left the Great Falls retreat littered with trash: teenagers toting coolers full of beer and looking for some outdoor partying.

County officials this weekend will launch a summerlong crackdown at Scott’s Run, with county police planning to ticket offenders for underage drinking and swimming in prohibited areas.

The enforcement effort is part of an attempt to address residents’ concerns that Virginia’s largest jurisdiction is allowing portions of its treasured park system to slide into disrepair amid limited resources.

Officials in the steadily changing county of 1.1 million residents are dealing with a wave of complaints that some of its parks have become too crowded, while others appear to be havens for crime.

“We want our parks to be safe,” said Sara Baldwin, a deputy director with the Fairfax County Park Authority. “When there are people in the parks who are using them appropriately, that’s the best thing.”

In particular, residents who live near the Holmes Run Stream Valley Park in the county’s Lincolnia section have been unsettled over the discovery earlier this year of two sets of human remains buried in a steep incline behind their cul-de-sac neighborhood — the focus of an ongoing murder investigation with possible links to the Mara Salvatrucha, or MS-13, transnational gang.

The park was the site of an MS-13-related murder in 2013, and, in the wake of the most recent discovery, local residents have pushed the county to do more about what they say is a regular flow of teenagers strolling into Holmes Run during school hours or on summer nights.

“You don’t know what’s happening back there at night,” said Zoya Melnichenko, whose rear porch deck faces the area where the two most recent bodies were found.

County police say they’ve been routinely patrolling Holmes Run and other county parks. Last year, the police department issued 35 citations for alcohol-related offenses inside county parks or playgrounds, including 18 “liquor law violations” that include underage drinking, according to county statistics. Police officers also handed out 144 citations for drugs or narcotics.

With 427 parks in Fairfax that make up a total of 23,400 acres of land and take in 17 million visitors per year, there aren’t enough resources for more aggressive monitoring, local officials say. The county, Virginia’s largest jurisdiction, has been trimming government services in recent years to balance the budget as revenue remains weak and demands from a rapidly changing population have grown.

Last week, park authority Director Kirk Kincannon told the county Board of Supervisors that his agency lacks the funds to adequately protect roughly half of the park land under its jurisdiction, mostly the undeveloped areas used for hiking, such as Scott’s Run.

Visitors to Scott's Run Nature Preserve are seen near a waterfall. Swimming and wading in the water near the falls is not allowed. (Matt McClain/The Washington Post)

“The maintenance is really, really important in our parks, and our parks badly need it,” Kincannon said during a committee meeting about the park system.

At Scott’s Run, the problem with teenagers drinking prompted the park authority to turn for help to the county police, who will patrol the area on bikes or on foot and issue fines of up to $2,500 for anyone under 21 caught drinking and for as much as $250 for swimming in a restricted area.

Problems inside other county parks will be referred to the police on a case-by-case basis, park authority spokeswoman Judith Pedersen said.

Though the underage drinking at Scott’s Run doesn’t appear to be gang-related, some of the teens have acted menacingly toward park authority workers who have seen them swimming in a natural pool below the waterfall and warned them that the county prohibits such activity, Pedersen said.

“The crowds have been really belligerent,” she said.

Pedersen said her agency’s main concern is that the partying will lead to an accident. The rocks near the waterfall can be slippery, and the undertow inside the pool below is deceptively strong.

“Swimming in that water isn’t safe,” she said. “It’s hard enough to do when you’re sober. With people who’ve been drinking, something bad is going to happen.”

On a recent afternoon at Scott’s Run, some parkgoers said they’ve mostly considered the partying teens an annoying disruption to the serenity they seek inside the nature preserve, where the steady rush of water echoes below a canopy of oak and birch trees.

“You can tell when school is out, because they all come here,” said Gilbert Ortega, 31, who was fishing for smallmouth bass on a Potomac River bank near the waterfall. “It’s usually really nice here.”

Merriam Mashatt, who has lived near the park for 20 years, said she frequently comes across glass shards from broken beer bottles near the trail entrance while out walking her dog.

“It’s like the kids sit on a bench and throw them,” she said.

Up on the waterfall rocks, two teenage boys taking in the view reacted warily to questions about the new attention from county officials.

“We weren’t drinking or anything,” one said. He declined to give his name before both scrambled down and left.