HALF MOON BAY — On July 4, several hundred people celebrated America’s birthday by trashing a gorgeous and secluded San Mateo County beach, a chunk of which appears to belong to “Wicked Game” crooner Chris Isaak.

As the hung-over revelers trudged back up the coastal bluffs to Highway 1 the next day, they left behind a shocking assortment of garbage: beer cans and bottles, spent fireworks, coolers, barbecue grills, condom wrappers, cigarette butts, food containers and much more.

Unfortunately for local nature lovers, it’s the latest of many overnight parties since 2015 that have left Tunitas Creek Beach, a wild expanse of sand just south of Half Moon Bay, looking like a stadium parking lot after a drunken tailgate party.

Littering on beaches and waterways is a problem throughout California, particularly on Independence Day. In May, fraternity brothers from the University of Oregon made headlines for leaving dozens of tents and other refuse on the shores of Shasta Lake.

But the trouble at Tunitas Creek Beach has gotten uniquely out of hand, according to coastal advocates and local officials. Entrepreneurs of debauchery have taken to throwing large parties — even raves, replete with generator-powered sound systems and disco lights — on the nearly mile-long strand, which is accessible only by hiking paths.

Complicating matters are questions of ownership and jurisdiction. Though many people, including some state officials, believe the beach belongs to the state of California, a spokeswoman for the State Lands Commission clarified Thursday that the dry sand between the surf and coastal bluffs most likely belongs to a pair of private landowners with property west of Highway 1 atop the cliffs. The owners include V Trust, a company linked to Isaak through county property and state business records.

San Mateo County and Caltrans have taken steps this year to curb the slovenly and often lawless behavior — posting no-parking signs at the intersection of Highway 1 and Tunitas Creek Road, for instance, and picking up some of the trash bags that visitors dump by the roadside — but county officials now recognize the need for even tougher measures at the beach, which does not have any facilities.

“It’s extremely disheartening,” said Brandy Chenoweth, a citizen who is leading the effort to restore the beach. Her volunteer group, known as the “TLC locals,” coordinates monthly cleanups in partnership with the Pacifica Beach Coalition.

“When it’s clean, this is such a pristine, beautiful, wild beach, and you don’t really want it regulated. This is one of the few that you can be at for free and camp for free,” said Chenoweth, who lived near the beach until February, when she moved to Santa Cruz. She works in Half Moon Bay. “But it’s really only meant for hiker or biker camping, because it doesn’t have any facilities — not large parties and raves every weekend.”

Kit Kuhlman, who dropped by the beach Wednesday on a visit from San Diego, struggled to understand how so many people could be so careless.

“Who do you think is going to take care of it?” the 27-year-old said while collecting garbage. “The ocean’s going to sweep it up.”

The parties at Tunitas Creek Beach started to get crazy last year, Chenoweth said, when unusually warm and fog-free weather drew big crowds to the coast. Word of the events began spreading on social media.

Around that time a handful of people who live on a property just east of Highway 1 illegally widened and graded a trail that follows Tunitas Creek down to the beach across the coastal landowners’ property. Then they began soliciting money from beachgoers to haul down their booze, food or gear, Chenoweth said.

“So now people are bringing down way more than they could ever pack down themselves,” said Chenoweth, adding the locals often say they’ll help bring the trash back up but seldom follow through.

One group of sybarites last month brought enough equipment to construct a MacGyver-esque hot tub on the beach, piping ocean water into a massive, tarp-lined pit in the sand.

Young people aren’t solely responsible for the trash, Chenoweth said. Plenty of families also leave garbage after gathering at the beach. Some of them cook up Dungeness crab they’ve poached from the surf zone.

California Fish and Wildlife Lt. James Ober said his agency cited the locals who expanded the trail, but the path has not been restored. Fish and Wildlife also regularly cites people who take crab out of season or without a recreational license, he said.

The California Coastal Commission is talking to the county about how to fix the trail, among other issues. Both the commission and Fish and Wildlife are concerned about possible effects on sensitive fish and other species that inhabit the creek, which has been befouled by trash and sediment — not to mention human excrement, which is also to be found up and down the beach near the bluffs, presenting a potential human health hazard.

Neither the state nor the county wants to prohibit access to the beach entirely. The public’s historical use of the beach, even if most of it is private, has likely established what is known as a “prescriptive right” ensuring continued access.

But more restrictions are in order, said county Supervisor Don Horsley, whose District 3 includes the coast. The county is looking into making the 10 p.m. to 5 a.m. no-parking zones on Tunitas Creek Road, which currently yield a $38 ticket, into tow-away zones and beefing up sheriff’s patrols.

The county is also talking to the coastal property owners about getting permission to enforce county ordinances and restrict overnight camping on their land, Horsley said. Representatives for Isaak did not respond to requests for comment.

Some party organizers are beginning to clean up after themselves. One group remained at the beach Tuesday, as electronic dance music thumped through their encampment, picking up trash with gloves and garbage bags. But many others haven’t gotten the message of taking out what they pack in.

Edmundo Larenas, chairman of the San Mateo County chapter of the Surfrider Foundation, said he finds himself in an ironic position. Though his organization has advocated forcefully for public access to the coast — including Martins Beach, a private property less than a mile north of Tunitas Creek owned by venture capitalist Vinod Khosla — he supports cutting back on access to Tunitas Creek Beach.

“When it’s a beach that’s far away from scrutiny, there’s folks with bad habits that ruin it for everyone, so in my opinion you need some control,” he said. “It’s why we have state parks and park rangers.”

Contact Aaron Kinney at 650-348-4357. Follow him at Twitter.com/kinneytimes.

How to Help There will be a volunteer cleanup of Tunitas Creek Beach at 10 a.m. Saturday. Participants will meet at the intersection of Highway 1 and Tunitas Creek Road south of Half Moon Bay.

To see more photos of the trash problem at Tunitas Creek Beach, visit www.facebook.com/san.mateo.county.times