Infrastructure in general, and parking lots in particular, are notorious for causing water problems. During a rain storm, a variety of factors combine to devastate local water ways.
The rainwater picks up contaminants, such as spilled oil and gasoline, and carries them into the environment, such as neighboring vegetation or rivers.
Most commonly, rainwater is channeled off of surfaces through piping. Fast moving, this creates 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 Nature Center is taking a number of steps to decrease these problems on its new site. The goal is to keep 100 percent of runoff on our 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 (see below).
For the parking lot, the “net zero water” started with an underground design. The parking stalls were carefully excavated lower than the driveway. In between small parking areas, vegetation will provide green buffers for visitors.
Underground, each “mini parking lot” serves as a pond. Water that falls on the driveway, and on the parking lot itself will stay in these ponds. Contaminants – whether its leaking oil or dirt from a tire – will settle out in the pond. The entire lot will be filled with large, clean rock, allowing significant amounts of rainwater to fill the space. On top of the rock, the driveway will be concrete and the parking spaces will be permeable pavers that allow the water to drain off in between them.
Ultimately, any extra water will make its way into a series of wetlands, where it can infiltrate back into the soil as clean, cool water.