Thomas, who said she had been down to the lake lots of times, said she never thought about fishing until yesterday.

"I just wanted to try and see if I could catch a fish," she smiled as she dipped a bamboo rod into the pea-green water.

The event, organized almost entirely by volunteers and through donations from Wahiawa businesses, was hosted by the state Department of Land and Natural Resources.

Gray tarps set up in the grassy bowl of Lake Wilson park housed displays and kiddie games, all with an environmental theme. Children huddled in groups along the lake's muddy banks, pointing and yelling as they dropped hooks into the water. Parents hovered nearby, arms filled with balloons, water bottles, umbrellas and tackle boxes.

"My wife grew up in Wahiawa, and (my kids) never saw the lake," said Grant Kim, 39, a business consultant. "It is an opportunity for them to learn about the lake."

Kim was waiting for the day's most popular attraction, a boat tour. With help from two local fishing clubs, kids and parents were given tours of the lake aboard fishermen's private vessels. The line for tours snaked halfway around the upper parking lot, and the wait ran almost 40 minutes.

"I want to spend a little time on a boat and go exploring," said Hoopi'o Kalani-Balaz. 9.

Yesterday's event was the third in six years. Shortly after the first Lake Wilson event in 1998, the aquatic weed Salvinia molesta began to choke fish, clog outboard motors and cover the lake to the point that no open water remained for fishermen to drop their lines, state officials said.

The invasion closed the lake to the public from January 2002 to November 2003, said Glenn Higashi, an aquatic biologist with DLNR and manager of Lake Wilson. Last year's day at the lake was partly a celebration of successful eradication of the weed.

Higashi said some Salvinia lingers in the lake, but it is cordoned off by buoys to an area smaller than an acre.

"It is under control and almost eradicated," Higashi said. "The fish population is healthy; there was no massive fish kill. It (Salvinia) didn't have too much of an effect."

A popular aquarium plant, Salvinia molesta invades so quickly that its sale has been banned in many states.

Anglers and others have now returned to the lake, thanks to the massive $900,000 state cleanup, which combined the efforts of hundreds of volunteers and dozens of groups, including the military.

Yesterday, however, was for the families.

"I want to bring the kids to enjoy," said Susan Seabolt, a 40-year-old housewife.