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Earth & Sky :More Info About Natural Drainage Page I of 9 About Ua Sponaon Nelp Cone MonCai Transc Today's Radio show More Information -Natural Drainage More on this Topic 'r' Comment o.= [his Shuw Previous Radio Shows Background: In 2000, the Seattle Public Utilities Department began construction on a pilot Earthcare project to reconstruct two city blocks using new technology to reduce storm water runoff. Edge of Discovery The effects of storm water runoff, especially after a torrential downpour, is T harmful to aquatic life. The rain washes pollutants from hard surfaces like Find Ea Women in Science roads that eventually ends up In lakes, rivers, and bays. On its way there, large volumes of fast-moving storm water causes significant erosion to creeks Your your Suenre QuesLOns and destroys its aquatic wildlife. E-Ne The Street Edge Alternatives (SEA) project was a new way to redirect We h. rainwater falling on impervious surfaces directly into the ground, keeping it diffe out of creeks, ditches, and storm drains. Rainwater seeping into the ground is update: naturally filtered by the soil to remove heavy metals and other pollutants, inform resulting in cleaner water entering aquifers, lakes, streams, and bays. In happeni addition, the absence of fast high-volume storm water runoffs preserves Sky. Si creek ecosystems. one th On the street that was part of the SEA pilot project, rainwater was directed into depressions along both sides of the street that contained composted soil, and was planted with water-tolerant plants. These "swales", as they're called,, act like mini-wetlands, holding the rainwater to let it percolate tnto the ground and be absorbed by plants. If rainfall Is heavy, the swales, which are connected to each other, are able to overFlow from one [o the other to redistribute the water load. This project turned out to be extremely successful; it was able to reduce storm water runoff by 98% at the two reconstructed city blocks. As a result, a new initiative called Natural Drainage Systems has been started to adapt the same technology to other areas of the city. An overview of that initiative, as well as Information on individual projects, can be found at the Seattle Public Utilities Department. Interview with Denise Andrews, Surface Water Program Manager Resource Planning Division, Seattle Public Utilities. SG: What kinds of pro}ects do you have in the works right now? DA: We're just completing a 15-block area that has two separate prototype streets. Both of these streets are using natural drainage systems. What that means is that instead of transferring the storm water through a series of pipes and walls, what we do is we try to Instead InFlltrate that storm water back into the ground, wherever it's falling within the street right-of-way. SG: http://earthsky.com/shows/showsmore.php?t=20041103 11 /8/2004