 |
Stormwater Management Manual (Green Infrastructure, Sea-Streets) Natural drainage systems (NDS) are an innovative alternative to traditional stormwater management systems. The pipes and ditches of traditional drainage systems carry runoff with traces of everyday contaminants such as oil, paint, fertilizer, and heavy metals. This contaminated runoff is then deposited directly into creeks, lakes, and, in Seattle, into Puget Sound. The speed and volume of water coming out of pipes erodes stream channels. These problems decrease water quality, disrupt marine food chains, and negatively impact wildlife habitat. Natural drainage systems limit the negative impacts of stormwater runoff by redesigning residential streets to utilize plants, trees, and soils to clean runoff and manage stormwater flows. Vegetated swales, stormwater cascades, and small wetland ponds allow soils to absorb water, slowing flows and filtering out many contaminants. Click here for more information. |
|