For three years it was just a big hole in the ground behind Seven Oaks Elementary School in Perry Hall.
Enclosed by a chain-link fence, the bowl-like excavation served as a storm-water management pond to capture excess rainfall -- an engineering requirement when the school was built.
Yesterday, that hole in the ground became a living laboratory.
Seven Oaks' nearly 700 students planted grass and flower seeds and bushes to turn the hole, 150 feet by 200 feet wide and 20 feet deep, into a miniature nontidal wetland that other schools are already clamoring to visit.
Principal Karen Schafer said environmental subjects are important at Seven Oaks and have evolved into a multidiscipline study that integrates science, math, geography and language. That means teachers are looking beyond their classrooms for practical applications.
Last year, the school mustered volunteers to carve a nature trail through the thickly wooded, stream-crossed area behind the building. Yesterday, delighted that they'd turned their book-learning into the real thing, the youngsters recited what they have seen on their wanderings.
"Turkey vultures, black vultures, red-shouldered hawks, red-tailed hawks, red-bellied woodpeckers, a red fox, two deer and a toad," they chorused.
However, the trail was only an appetizer for the Seven Oaks faculty -- which looked for new worlds to conquer.
The pond! How could it be turned into a practical outdoor classroom for the children while retaining its original purpose?
No one knows whose brainstorm the wetland was, Ms. Schafer said, but it clicked and faculty members turned on the networking jets to find the people who could make it work.
They won cooperation from the Baltimore County government and several private organizations, including the county's Forest Conservancy District Board, the U.S. Fish and Wildlife Service, the National Civilian Conservation Corps and the Chesapeake Bay Trust, which provided a $6,000 grant.
Tuesday, a bulldozer leveled the floor of the bowl, leaving four smaller pond areas connected by shallow ditches.
Next spring, the ponds and swales will be marshy and will be planted with native plants that thrive in wet areas.
Meanwhile, the first stage went ahead yesterday, as one class sowed quick-sprouting rye grass seed mixed with wildflower seed. Then kindergartners covered the seeded area with straw to protect the growth.
Next came the upper grades. Some students planted roots of blueberry, blackberry and chokeberry bushes -- which will grow to provide food for birds -- while others dug holes for sweet-pepper bushes, mountain laurel and red osier dogwoods.
"Every grade level can use these wetlands. Things they learn in science they can adapt to real experience," said fourth-grade teacher Barbara Lardieri.
Ms. Lardieri was as enthusiastic as any of the students as she talked about the Nature Club and the youngsters' preparations for the Great Day.
Over the weekend, Chris Hubicki, 8, a fourth-grader from Carney, brought his father, Joe, to pace off the bowl's dimensions for the topographical scale model they made with layers of corrugated board.
"Chris gave everybody a visual representation of what it would look like," Ms. Lardieri said.
Chris' map and yesterday's plantings showed the integration of disciplines, she said: mathematics figured in the calculations for the map, and the students measured the various planting areas and the distance between plants.
Handicapped students have easy access to the floor of the bowl on a path of crushed stone.
Thomas L. Burden, the Chesapeake Bay Trust's executive director, came to watch the youngsters at work yesterday.
He said the Seven Oaks project is the first of its kind in Maryland and a pilot for the trust's participation in similar projects elsewhere.
The trust, created by the General Assembly in 1985, seeks corporate and private contributions, which it distributes to organizations that undertake projects to help the bay.