Weekend crowds at the Peekamoose Blue Hole in Denning are thinning out.

Anyone who wants to swim in this world-renowned swimming hole on weekends or holidays now has to sign up in advance.

The new permit system will stay in effect until October 15.

Viviana Orozco, a regular visitor from New York City who is here with a group of about 20 friends and family, said she is glad the Department of Environmental Conservation began limiting swimming hole permits on high-traffic days to 240 visitors.

Litter has been an issue in the past.

Orozco did not see much litter during the group's visit on Sunday afternoon.

"Now, there's more control, and now it's cleaner," Orozco said. "You can see now, it's cleaner."

The litter problem -- which currently appears to be taken care of -- began in 2015, when a flurry of positive articles about this section of Rondout Creek inspired several trips here.

On busy days, the hole would draw up to 800 people.

"This is a really small place for that many people," Blue Hole Steward Coordinator Andy Mossey said during a tour of the site.

Mossey, who coordinates a team of environmental stewards recently assigned to the swimming hole, said the permit system has helped minimize overall environmental impact, has helped stewards keep track of visitors and has given stewards time for their educational campaign.

Mossey took several quick breaks on the tour to stop and chat with visitors, asking them how their experience was and sharing from his breadth of knowledge about the local geography and history.

The stewards have set up a informational booth at the trailhead, reminding guests that the Blue Hole, is part of Rondout Creek, which is part of the watershed that provides drinking water to New York City, where many of the hole's visitors hail from.

Mossey believes that if visitors know this hole is connected to their drinking water supply, they will treat it better.

"They're actually swimming in what turns out to be a water supply for them," Mossey said. "It's another reason why it's so important to keep this water so pristine."

Permits are free, and can be reserved through the New York State Parks Permit Reservation Website.

Mossey said anyone seeking a permit on the day of, or day before, a visit will likely miss out, since permits are being snatched up so quickly.

He advises reserving permits at least a week before a planned visit.