COVER STORY : Taking the Plunge at New Theme Park : The chutes and slides at Hurricane Harbor promise thrills and chills on hot summer days.

A shady river flows through the center of Six Flags Hurricane Harbor, wending past the new water park’s dozen or so attractions. To one side, crumbled icons surround a ceremonial wave pool. To the other, a giant pirate skull spouts plumes of water.

But all the kids want speed.

They find it in a far corner, where three slides descend sharply from the decrepit-looking Taboo Tower. Screams ring through the sunny afternoon as tiny bodies plummet down 300-foot chutes.

“It looked too steep at first,” said Deshawn Williams, 10, of Los Angeles, who spent 10 minutes at the top before mustering enough courage to take the plunge. “You go straight down. That’s what makes the fall so much fun.”

It figures that Six Flags California would include a few thrills in this 14-acre water park that stands beside the roller coaster-filled Magic Mountain. The $35-million Hurricane Harbor, which opens today, will operate as a separate park with a separate admission fee. As such, it represents the first theme park built in California since 1986.

The emphasis here, in the brown foothills of the Santa Clarita Valley where summer temperatures often top 100 degrees, is firmly on water. The grounds have been landscaped with green foliage, rows of food stands that promise cold drinks, and 10 major slides of various daring.

Guests fly down the Tiki Falls’ dim and enclosed tubes on brightly colored rafts. The open chutes that twist wildly from Lightning Falls have such daunting names as “Tornado Twist” and “Thunder Trough.”

“Whoa,” said Jim Ventress, 45, of Los Angeles. “Are we pulling some Gs here or what?”

Not everyone craves velocity. Scott VanDyne, 11, of Newhall took one look at Taboo Tower and shook his head, turning to the Forgotten Sea wave pool where inflated rings undulate on two-foot breakers.

“Those waves are just big enough to get you wet,” VanDyne said. “It’s like being at the beach.”

After an hour at sea, he took to even calmer waters in The River Cruise that circles the center of the park. He joined other rafters who drifted through the shade of rock formations and ancient-looking archways.

“On a hot day,” Ventress said, “this is the cool ride.”

And Hurricane Harbor has included a milder water slide, the Lost Temple Rapids, where guests follow gentle curves in four-person rafts. Such tame attractions are meant to amuse small children while older siblings go for broke.

“That’s the advantage of a water park,” said Tim O’Brien, a regional editor for Amusement Business magazine. “You’ll see an 8-year-old boy with his 12-year-old brother. Mom and Dad will be playing with their 3-year-old sister. They’re all coming in the gate together.”

While Southern California already boasts a number of large water parks, O’Brien credits Hurricane Harbor’s designers for taking the concept a step further with Disney-style looks.

Giant statues, fashioned after Tiki and Easter Island sculptures, crowd the walkways. Foliage blocks sight lines to create an enclosed environment. Only a few of Magic Mountain’s neighboring coasters rise above the trees.

Such attention to detail has resulted in some trivial twists. A row of clam shell fountains in the Shipwreck Shores playground, for instance, come from the old Pacific Ocean Park on Santa Monica Pier. A nautical figurehead was salvaged from the film “Mutiny on the Bounty.”

“They are doing a really A-1 job,” said Dave Bruschi of the World Waterpark Assn. in Lenexa, Kan. “It makes their park stand out from a lot of others.”

Maybe so. But Laura Besenty, 11, and her stepsister Jennifer Ingelido, 13, could care less about atmosphere. They came to Hurricane Harbor for one thing only.

“The thrill,” Laura said.

Jennifer nodded: “Speed.”

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WHERE AND WHEN

What: Six Flags Hurricane Harbor.

Location: Magic Mountain Parkway, Valencia.

Hours: Open at 10 a.m. daily through Oct. 1. Closing hours vary.

Price: $16 general admission, $10 for seniors and children shorter than 48 inches, free for children 2 and younger. $43 for combination ticket to Hurricane Harbor and Magic Mountain.

Call: (805) 255-4111.

Rides That Make a Splash Hurricane Harbor features shops, food stands and eight major rides:

Castaway Cove--a pirate-themed play area for children.

Shipwreck Shores--another play area for children.

The River Cruise--a 1,300-foot river for slow rafting.

Tiki Falls--features three enclosed slides.

Lightning Falls--features three open slides.

Taboo Tower--features three speed slides.

Lost Temple Rapids--a slide for four-person rafts.

Forgotten Sea--a wave pool for rafts and sunbathing.