San Francisco residents and officials are bracing for tens of thousands of people to flock to Golden Gate Park on Thursday and light up at a massive annual pot party.

Board of supervisors President London Breed made it clear at a news conference on Wednesday that the event is not sponsored by the city.

However, over the years, cleaning up the garbage left behind by pot smokers has been problematic, so city officials are teaming up with a private sponsor to help pay for additional resources.

In a statement, Breed said: “Love it or hate it, the culturally historic "4/20 festival" is not going away, and it has a significant impact on our city, on our district, and on our parks. Past "4/20" festivities have led to horrific traffic, overwhelmed residential streets, public urination, damage to public and private property, and strained police, Muni and park resources.

“And on the following day, 4/21, dozens of City staff members and volunteers have had to laboriously collect over 10,000 pounds of litter left in the parks.”

There also were complaints about traffic, public urination and property damage.

To keep the event more secure, a higher-than-average number of police officers and medical personnel will be stationed in the area. Also, only adults will be allowed into the park, which will feature a gated perimeter and preapproved food stalls. Officials will also install portable trash bins and bathrooms across the venue.

“There will be no drugs for sale, no unauthorized music, no unpermitted concessions, and no alcohol,” Breed wrote.

Although 4/20 is not officially approved by San Francisco leaders, Breed hopes a “well-oiled plan” will lead to a “cleaner and safer” event for all attendees.

Neighbor Stacy Kolsrud is skeptical.

"They can try, but I don think they will succeed," Kolsrud said. "It's like a bunch of teenagers."

Deb Harms and Shanna Leblanc drove in from Utah for the unofficial tribute to marijuana use. They've heard restrictions are coming.

"Too much controlling will change the event to make it not as fun for everybody," Harms said. "Part of the whole thing, it was the whole hippie culture."

At this time, there are no planned street closures around the park, but that could change, officials say, depending on how the party pans out.

NBC Bay Area's Christie Smith contributed to this report.