What’s on top of this hillside is as much a lesson in nature as what's underneath and behind it.

"It is built into the side of a hill, of course, and part of that had to do with the piece of land that was purchased, it was the logical thing to do given the slope. But then the architects also wanted to be proactive and build something green. At the same time, even though we're built into the side of a hill the whole front is open, so we don't feel closed in, it's a very nice, comfortable building, library manager, Pam Locker says.

The architect of this library worked with the land.

His roof is a low maintenance prairie and in the summer it blossoms into a sea of wildflowers.

"The roof will absorb the rain water. About 90-percent of it will be returned to the earth instead of going into the storm water system,” architect, Michael Shoulders says.

The green design doesn't stop with the roof. Shoulders ditched the usual lawn for a man-made wetland.

"What it does is the natural plants and micro-organisms can cleanse the water that comes off the parking lot that may have oils, salts or petroleum in it and by the time it gets to that lake the water is almost 90 to 95-percent pure water," Shoulders adds.

A wetland works a lot like your kidneys. It filters run-off through an eco-system that's as old as time. These natural marshes are even being looked at on a grander scale as substitutes for expensive water treatment plants.

"If we expand on nature and we build on the wetlands that are already given to us, I think it's a cheaper and a wiser solution than building grandiose concrete storm structures," Shoulders says.

50 billion dollars a year is currently being spent on green construction projects.
That number is expected to skyrocket in the coming decade.

The library was built four years ago, and has won a number of national design awards. The rubber roof that lies below the meadow has a lifespan of about 30 years.