Infrastructure in general, and parking lots in particular, are notorious for causing water problems. During a rain storm, a variety of factors coalesce to devastate local waterways. The rain water picks up contaminants, such as spilled oil and gasoline, and carries them into the environment, be it neighboring vegetation or rivers.
Rainwater is frequently channeled off of the surface through piping. This creates fast moving, focused torrents of water that erode the surrounding soil, carrying silt into the rivers and creeks. Cloudy water makes it impossible for some fish and other wildlife to live.
The Indian Creek Nature Center is taking a number of steps to decrease those problems on its new site. The goal is to keep 100 percent of any runoff on its own property-even during construction. Areas were excavated to temporarily hold any rainwater during the project. We had five inches of rain last week, and the dirty water stayed where it belonged.
For the parking lot, the “net zero water” started with a complex underground design. The entire parking lot will be filled with large, clean rock that has significant void space. This allows a lot of water to stay directly under the parking lot, and the contaminants-whether its leaking oil or dirt from tires-to settle out before the water moves on.
On top of the rock, the driveway will be concrete and the parking spaces will be permeable pavers that allow the water to drain down, not off. Below are the individual cells, or series of underground ponds that hold and slow the water, taking shape.
Ultimately, any extra water will make its way into bioswales, where it will support native plants and can infiltrate back into the soil as clean, cool water.