Angela Sullivan remembers how crowded the playground at Lake Elkhorn Park was on Sept. 2. Kids and adults were everywhere when Sullivan, who was at the playground with her three children, heard someone calling loudly, "Has anybody seen Alex?"

Right away, she said, adults scattered to look for the child. A few minutes later, as they gathered back at the playground, they heard a woman screaming. Twenty-three-month-old Alex Ferrera, who was at the lakeside playground with his day-care provider, was found floating in the water. Sullivan, trained in cardiopulmonary resuscitation, rushed to the lake, where an off-duty Secret Service agent and a nurse were trying unsuccessfully to revive the Laurel toddler.

Across the road, at a McDonald's restaurant on Cradlerock Way, Jennifer Terrasa and her preschool daughter were preparing to go the playground when a group of mothers and their children arrived, clearly shaken. She remembers the shock and sadness she felt, but also the fear. "Oh my God, it could have been me."

In the days since the drowning, these two Columbia mothers have been compelled to do something beyond e-mailing friends about the accident, the kind that haunts parents of young children.

Terrasa appeared at last week's meeting of the Columbia Council and told the panel that she won't take her three children to the park without extra adults to supervise. Terrasa, a lawyer who serves on the King's Contrivance village board and Howard County Planning Board, gave the council a petition signed by 90 people who want the playground enclosed with a fence.

"That playground is really unsafe," she said, noting there's only a grassy slope of a few dozen feet separating the playground from the edge the water. The child's death, she said, "was a tragedy waiting to happen."

The 37-acre, man-made lake was built in 1974 and is overseen by the Columbia Association. It is used by boaters and fishermen, but swimming is prohibited.

Terrasa said Chick Rhodehamel, the Columbia Association's vice president of open space management, told her last spring that there was no public demand for enclosing the playground. The association spent $105,000 this spring to purchase new playground equipment but did not consider the possibility of fencing the area, said Karen Hawkins, general manager of community relations and communications for the association. CA staff members periodically review the association's risk management guidelines for Columbia's open spaces, she said.

"We're looking to the council for guidance on the next steps, if there are any," Hawkins said.

During last week's meeting, council members expressed sympathy for the child's family but told Terrasa that they weren't convinced that a fence is the solution. Maybe planting shrubbery could provide a barrier, they said. Terrasa wishes she had pushed harder on the matter months ago.

"I kind of feel like I should have jumped into action sooner," she said.

Meanwhile, Sullivan has written and called several Columbia Association officials. She has heard from Oakland Mills council member Barbara Russell, who told her that the council was awaiting a recommendation from its staff members.

Sullivan said the child's death has dominated conversation among her friends.

"Everybody has felt something needs to be done," she said. "As residents of Columbia, we feel we should have a say in how open space is structured."

Despite her children's pleas to return to the playground, Sullivan doesn't know when they'll return. Last Friday, it was quiet, with just a few visitors.

Seated on a playground bench were a couple of moms, who talked about the responsibility of adults caring for young children and pondered whether a fence would mar the view of Lake Elkhorn's placid waters.

As they sat, a young man in a dark suit and sunglasses strode by, heading for the dock with a bouquet. After a few moments, he walked away, leaving the flowers floating in the water at dockside, near an impromptu memorial of faded blossoms, a butterfly balloon and a purple stuffed bear.

"To Alex Ferraro [sic]," read a small card taped to a piling. "You are an angel in the sky."

Angela Sullivan with Joey and Jennifer Terrasa. Said Sullivan, "Everybody has felt something needs to be done."