Elizabeth Dapper, 11, wanted to grow up to be a mermaid. She'll have to settle for lifesaver.

Goggle-eyed Beth was prowling beneath the splashy blue surface of the Algonkian Regional Park pool in Loudoun County on Wednesday when she saw a 6-year-old boy curled up on the bottom in 41/2 feet of water. She couldn't tell whether he was joking or in trouble. Then she got a closer look.

"His eyes were rolled back, and it didn't seem normal. It freaked me out," Beth said yesterday.

She dived down to grab the boy's arm, lifted his limp body to the surface and saw that he was unconscious. She put him over her shoulder and headed to the side. "It was scary, because I thought I was holding someone who would be lifeless, you know, dead," she said.

A lifeguard rushed over, grabbed the boy from her and started performing lifesaving techniques. The boy started coming back.

"The child coughed up liquids and began breathing," said Derric Bolton, safety officer for the Northern Virginia Regional Park Authority, which runs Algonkian and four other pools in the region and oversees the lifeguards.

The boy was given oxygen at the pool, and Loudoun fire and rescue workers took him to a Reston hospital. He was released late that evening and is doing fine, Bolton said.

Beth sounded cool and collected as she recalled the incident yesterday, but the emotional poolside scene has continued to reverberate. Beth started crying after handing off the boy, and was helped out of the pool. "I broke down when I got out of the water, I was so sad," she said. Other kids surrounded her and began thanking her and comforting each other.

Beth's father, Thomas Dapper, said that his daughter shouldn't have been put in that position.

"It's fantastic what she did, but I'd rather she'd not gone through that," Dapper said. "It was a good thing to do, but to find a body that needed to be resuscitated was traumatic."

Park authority officials said lifeguards did what they were trained to do and would have saved the life of the boy, who came to the pool with a Loudoun County-run summer camp. Still, they were thankful for Beth's actions. A 6-year-old D.C. boy drowned at the same facility in 2001.

Gary N. Fenton, the authority's executive director, said the lifeguard responsible for that section of the pool said she saw the boy at the bottom of the pool before Beth acted. He said the lifeguard was following procedures by not immediately whistling an emergency alarm and jumping in for a rescue.

"We get kids on the bottom all the time," Fenton said, adding that lifeguards are trained to scan the horseplay-filled water in a regimen that takes 15 seconds.

The lifeguard had her eye on the boy, Bolton said; once she saw him on the bottom, she "fixated" on him.

"The guard would have gone in a few seconds later," Fenton said.

Beth was back in the pool yesterday.

"Every time I went by that same spot, I just pictured him," she said. "It just freaked me out."

Elizabeth Dapper says she started crying after the rescue. "I broke down. . . . I was so sad," she said.