Christopher Darrah, who will be 2 in August, had decision-making thrust on him early the other day at the Cameron Run Regional Park water playground in Alexandria.

Christopher and his mother, Joann Darrah, of Alexandria, had planned to slide down a children's water slide hand-in-hand. The flow of the water down the slide, however, caught Darrah, and she slid on down alone, leaving Christopher at the top of the short ramp slide.

He paused briefly, considered his options, adjusted his orange water wings, and went for it, sliding down perfectly into his mother's arms.

"This is our first time, and he's having the time of his life," Darrah said. "He has so many things to do, he's going in a million directions."

Christopher is not alone in his delight with romping through the new $850,000 complex of pools, slides, water toys, sprinklers and batting cages that dot this 31-acre park off Eisenhower Avenue. Brian Hennesy, the park's director, said Cameron Run, which boasts the only wave pool in Northern Virginia, brings in about 40,000 swimmers a year.

"On a busy Sunday afternoon, you can walk across the length of the wave pool on a sea of rafts," Hennesy said. Weekday attendance varies, but park officials estimate 500 people come to the complex daily.

"We've tried to appeal to everybody, from toddlers right on through to senior citizens," said Darrell Winslow, executive director of the Northern Virginia Regional Park Authority, which operates Cameron Run.

From the 17,500-square-foot wave pool to the children's playground featuring spouting turtles, bouncing alligators and a 21-foot-long foam snake, Cameron Run is offering the area something unusual, according to its builder.

"This park is in the forefront of a trend by municipalities to build pools with children's features, and it's certainly the most comprehensive complex in the area," said Paul Houser of the Paddock Swimming Pool Co. in Rockville, which built the new complex. Houser said that a similar site is being developed in Poolesville, and that some slides are open at a center in Gaithersburg.

"But right now, no other municipality has this range of play features," Houser said. "Cameron Run is breaking new ground."

The addition of the water playground complemented the wave pool, which opened in 1984. "This has jelled the whole place together," Hennesy said. "Small children now feel they've got more to play in than just a little wading pool."

The playground's water depth ranges from 16 to 24 inches, and the wading pool from zero to 12 inches.

An 1,800-square-foot wading pool is behind a large stone formation that offers small children two slides that take them into the water playground. The three largest water slides, which are intended for children over 6, tower over the playground.

"It's funny," said Hennesy. "People drive by, and you can see them stop and wonder what exactly we are."

A lap pool, aimed at serious swimmers who might want to avoid spouting plastic turtles, is adjacent to the water playground.

A staff of 55 runs the park, with 25 lifeguards standing watch over the various pools and slides.

The batting cages at Cameron Run are outside the water complex, and are open from March through October. One dollar buys 25 pitched balls.

The hours of the park, which opened in June, are from 10 a.m. to 8 p.m. Admission is free for children under 2, $6 for children under 12 and senior citizens, and $7 for those from 12 to 59. After 5 p.m., admission is $4.50 for adults, and $3.50 for children and senior citizens.

Coming from the Capital Beltway, visitors should exit at Telegraph Road north and follow highway signs directly to the park entrance.