Celebrating Water
Knoch Knolls Nature Center puts a spotlight on its biggest asset
By Lois Vitt Sale
NATURE IS LOCAL. While the sun rises in the east and sets in the west, what happens on the ground varies greatly. Whether it is in a hardwood savannah, on an open prairie, or in a desert, creating a building for a space places it inside a unique ecosystem.
With most design assignments, we are asked to fulfill a program — to create a school or an office building — and the functionality of the building dominates the dialog. Have we created an atmosphere where children in classrooms or employees in offices will thrive? When designing a nature center, however, the dialog shifts because the spotlight is on nature and creating an intersection between the built environment and nature, where the building will bring the unique properties of the ecosystem in focus to create opportunities to learn. While, of course, we want the occupants’ needs to be met, we want them to engage with their setting — to use the building but also to immerse themselves in nature. And we want them to learn about the ecology of the site through the building as it demonstrates its integration with nature and its use of ecosystem services. Knoch Knolls Nature Center, a new facility designed and built by Wight & Company for the Naperville Park District in Illinois, is a textbook example of this approach to design.
Selecting A Theme
When residents were surveyed about what types of facilities they desired, they identified the need for an environmental learning center. And Knoch Knolls Park — a 224-acre park on the south side of Naperville — was selected as the optimal site for the facility. The first order of business was to look for the unique, natural blueprint of the site. The park sits at the confluence of the east and west branches of the DuPage River, and much of the parkland sits in the flood plain and flood way for the river. Clearly, the dominant theme for a nature center on this site is water!
The ways the building tells the story of water are numerous and multi-faceted. To begin, the building was sited on a parcel of land that is out of the floodplain but sits at the edge of an old farm pond. The pond was reshaped to engage with the edge of an outdoor deck that serves as a visible link between building and water.
Rethinking Parking
For every facility that serves people, there is the question of parking. Where will it go? How much is needed? How will we compensate for the stormwater that sheet flows over the parking surface? At Knoch Knolls, existing parking was accommodated in a large gravel lot that ran from the street to the banks of the river. Much of it was in the floodplain and routinely washed away when water overtopped the banks of the river. Gravel lots are pervious and do allow water to re-infiltrate into the ground, but the constant wash out here was definitely a negative. The solution was to relocate the parking lot out of the floodplain, closer to the street. A lot made of pervious pavers was installed to replace the existing lot so the rain that falls on it can be infiltrated into the ground. Also, the pavers were light in color to avoid microclimate changes from absorbing and re-radiating heat, as asphalt lots do.
Parking lots are often located as close to the buildings they serve as practicable. In this instance, the decision was made to locate the parking a stream away from the building. So the main approach to the nature center is across a culvert and through a steel sculpture of a mill that recalls a historical link between the river and the people.
Resourceful Rainwater
In the building, rainwater is a resource. The rooftops serve to capture and direct the water. The rooftop over the western end of the building — which a visitor first sees in approaching the facility — is butterfly-shaped to funnel water to its center valley where it flows to an inlet and from there into a cistern. Several sloped roofs at the eastern end of the building also collect and direct water. That water first passes through a stone-filled runnel that crosses a flat vegetated roof before dropping into the 1,500-gallon cistern that sits in the lobby of the building.
Harvested rainwater is utilized to irrigate a living wall in the building and to supply all of the building’s flush fixtures. The living wall, or bio-filter, serves as a filter on the return air system in the building. This filter uses the root system of the plants to excise pollutants from the return air so it can be re-circulated in the building and reduce the energy burden from conditioning outside air to ideal inside temperatures. Between water-conserving fixtures and the use of captured rainwater, the building will save 56 percent of the water it would have used without the use of these strategies.
Visitors to the building cannot fail to see the cistern since it sits in plain view in the lobby and is approximately 6 feet in diameter. A clear tube off the cistern acts as a gauge reporting the water level so visitors can see the impact of rain or drought on this precious resource. On the occasion where the rain is more than the cistern can hold, an overflow pipe runs directly to the pond and deposits the overflow there.
Of the numerous exhibits that fill the lobby with stories and images of the river and people’s connection to it, the favorite is, perhaps, a tank that wraps around the cistern and is filled with fish and plants found in the DuPage River. Visitors can see what species of flora and fauna live in the river and are offered a peek beneath the surface of the river.
Additional Conservation Efforts
Beyond the story of water, this nature center earned LEED Platinum certification, signifying it also conserves resources in many other categories:
- Using 57 percent less energy than a similar code-compliant building
- Producing 21 percent of its power from a building-integrated photovoltaic array
- Diverting 75 percent of its construction waste from landfills
Implementing many strategies to deliver a healthy indoor environment with copious amounts of daylight, views of the surrounding parks, and a selection of materials chosen to deliver a clean, breathable building.
In the end, it will not be the reduced energy and water bills that visitors see when they visit this facility. Instead, it is a love of water and its natural cycles and an enthusiasm for how buildings and nature can intersect to the benefit of both. PRB
Lois Vitt Sale is the Senior Vice President/Chief Sustainability Officer for Wight & Company. As a practicing architect for more than 25 years, Lois’ career goes well beyond the domain of project design. She has been a national leader in the application of private and commercial green technologies and sustainable planning to the public and private sectors. For more information, visit www.wightco.com.
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