Changing travel habits are playing a big role in the parks' popularity, said Gina Kellogg, communications director of the World Waterpark Association in Overland Park, Kan. "Most people today simply don't have the time to get away for the traditional two-week vacations of the past," she said.

"That makes a weekend getaway to a water park a perfect vacation. ... Since 9-11, this trend has become even more pronounced."

The water-park industry wasn't even born until 1977, when George Millay, the father of the modern water park, opened the world's first - Orlando's Wet 'n Wild.

The Beach Waterpark opened in Mason eight years later with a wave pool, two activity pools and four slides. Today it has 49 attractions.

Paramount's Kings Island dove in in 1989 with the 13-acre WaterWorks, which had 15 slides and a kiddie area with a shallow pool. Today, its new Crocodile Dundee's Boomerang Bayfeatures 60 attractions.

By the mid-90s, virtually every theme park in the country had a water park attached to it. "They found out it was good for business," said Speigel. A large part of the appeal was access to two parks for the price of one.

Bill Koch, president of Holiday World in Santa Claus, Ind., calls his decision to add a water park in 1993 "the smartest business decision I ever made." Since then, the park has added at least one wet attraction a year and Koch promises to continue that as long as visitors stream in.

Today's water park bears little resemblance to those early efforts. Tomorrow's will bear even less, given the trends.

• Togetherness: Market research has made it clear people would rather do slides in groups than alone. In response, new attractions in parks across the country this year include large rafts that seat four and side-by-side racing slides where family members can compete. Brothers Tim, 16, of Xenia, and Joe Habedank, 18, of Morristown, Tenn., tackled the four-slide Coolangatta Racer at Kings Island's Boomerang Bay last week.

"It's always more fun when you're in a group and can race," Joe said. "Tim won twice and I won once."

Kings Island's new Tasmanian Typhoon and Holiday World's year-old Zinga both feature long, enclosed, 65-foot-high slides that empty into a gigantic funnel where rushing water drives the four-person raft high up the sides.

"Single slides are fun, but the group slides are better, because you get to laugh at each other," said Kyle Miller of Loveland as he and his family exited the Typhoon.

"Water parks went through their period of taller and faster slides, but then they found out people like to do things in groups," Speigel said. "You watch, within a few years, there'll be a funnel slide in every park in the country. I know Cedar Point has already been down here looking at it, so you'll probably see one there soon."

Likewise, be on the lookout for more water forts. These are multi-purpose attractions in which an unlimited number of guests can play together. They include water cannons for shooting each other and passers by, smaller slides, geysers, climbing apparatus and 500- or 1,000-gallon buckets that periodically rain water on guests.

The added benefit of multi-person attractions, says Kellogg, is shorter lines.

• Amenities: Better food, full-service bars, poolside servers, upgraded changing rooms, and more expensive and comfortable lounge chairs are becoming standard.

At Kings Island, servers with orange flags run frozen pina coladas or an upscale lunch of grilled shrimp to lounging guests. You'll see guests sprawled out in a row of private cabanas - each equipped with lounge chairs and 'fridges - in a restricted poolside area only renters can enter. Cedar Point features Bubbles, an adults-only swim-up bar with underwater barstools. At Holiday World, visitors can duck into huts for free soft drinks and sunscreen.

• Indoor water parks: They're the fastest-growing segment. In 2003, there were 62; in 2004, 46 went into the planning or construction stages, more than half of them in the Midwest. Sandusky has one open and two more set to open this fall. Two are under construction in the Poconos. Two more have been proposed for Mall of America. And Wisconsin-based Great Lakes Co. is hoping to build a $60 million indoor park in Mason within the next two years. In almost all cases, these parks are attached to a resort and open only to resort guests.

• Improvements: With more than 1,000 parks out there, the market is saturated, Speigel said. So instead of building new ones, the industry is concentrating on improving existing ones by adding new attractions, upgrading landscaping and updating the infrastructure. This year, the Beach spent an estimated $2 million on fix-ups and tropical plants - "things the public doesn't notice until you don't do it," said Tara Nahrup, the park's marketing manager.

• Patterns of use: When theme parks added water parks, the thought was that guests would spend most of their time in the land park and visit the water park just to cool down. But given the relatively low cost of season passes, a significant number of people make water parks what Speigel calls "their local country club" - they arrive early, grab a chair and never leave.

"I'm a diehard," said Sue Beiting of Fort Thomas. "I'm here (Boomerang Bay) three days a week and very often it's the water park only. We belong to a swim club in Fort Thomas but the kids like it here better."

Harold Dishman of Monroe said almost the same thing: "All I do is the water park. My wife does the land rides but I never do. And I only do the group slides when I'm here. No singles."

That's also true at Cedar Point, said public relations coordinator Bryan Edwards. "We have people come in here in the morning, stay all day and never visit the land park. For a large number of our guests, this is their private club.

"We expect to see a lot more of that in coming seasons."

E-mail jknippenberg@enquirer.com