WATERLOO - The group of science teachers spent the week seeking out Iowa's physical features.

They found it - and many rock samples - at area quarries, gravel pits and cement plants.

But on Friday, as part of a Geology of Iowa workshop, the teachers traipsed through a place that does not usually come to mind when thinking of natural formations: the Black Hawk County landfill.

"Basically, we've come out here to see a well-developed, a well-run landfill," said Jim Walters, a University of Northern Iowa geology professor who led the workshop. "We don't want to neglect that in terms of the things we do."

He added, "It's sort of what's happening with the landscape. We've got our own activities that are changing the landscape."

The workshop, which just finished its third year at UNI, gets teachers out of the classroom for a closer look at the state's geology and topography. The Iowa Limestone Producers Association funds the workshop, covering tuition, room and board and class materials. It drew 24 elementary to high school teachers this year from across the state.

At the landfill south of Waterloo on Washburn Road, solid waste administrator Gary Wilcox led teachers along a road through part of the 300-acre site. The landfill receives 500 tons of garbage per day from communities in the county plus Fairbank and Jesup.

The teachers walked past a mountain of chopped up rubber tires that will be used to line one of the cells where garbage is dumped. Further up the road, Wilcox showed them an area where topsoil is being stripped away to cover fresh garbage every day - a minimum of 6 inches on 10 feet of trash.

In between, he pointed out the prairie grass that had been planted on areas where garbage is no longer being dumped. Before planting, the ground is covered with several feet of clay and topsoil.

"We've got about 60 acres of prairie," Wilcox said.

The land provides habitat for rabbits, deer and numerous bird species such as pheasant, red-tailed hawk, goldfinch and even some eagles.

Susan Ramhorst of Spirit Lake, a high school special education teacher in the Hartly-Melvin-Sanborn School District, was not surprised by the environmentally sound practices the landfill uses.

"This is not my first experience at a landfill," she said. "It's nice to see what they're doing here."

She has taken special education students to landfills in the past as part of teaching earth science. Friday's tour provides her with more knowledge to take back to the classroom.

"The environment is a favorite of mine," she said. "Even if they don't understand the concept of science, they can understand saving the earth."

"You have to make the connection between what we teach and what's real," added Mike Rathe, a physics teacher at Ottumwa High School. "You don't make the connections until you see it. So, it gives you some ideas."

The landfill visit gave him more than ideas, though. Rathe was carrying a small plastic wheel that Wilcox helped him remove from a discarded cart they passed. At school, he uses the same brand of cart, which needs a new wheel. Rathe had looked everywhere for a cheap replacement, but couldn't find one until discovering the cart Friday.

"It was going to cost me 20 bucks to put a different wheel on it, and this cost me nothing," he said. "So I was exuberant, it made my day."