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Raingardens Effectively Treat Stormwater Runoff



Stormwater is the #1 cause of water pollution in the United States according to the Environmental Protection Agency. Stormwater runoff occurs when rain falls on impervious surfaces such as pavement, sidewalks, roof, etc. where it cannot be absorbed into the ground, so it runs off the surface. This runoff picks up many pollutants (such as sediment, nutrients and bacteria) on these surfaces before flowing into storm drains in urban communities.  These storm drains send the polluted runoff straight to a streams, lakes or wetlands UNLESS there is a stormwater best management practice (BMP) in place to capture and treat the runoff.   Examples of BMPs include raingardens and filtration basins, which capture stormwater runoff in a shallow depression where fast-draining soils allow quick infiltration and removal of pollutants as water passes through. Plants in the BMP absorb nutrients (phosphorus) that cause algae blooms.

Two of the pollutants raingardens and other stormwater practices are designed to remove from runoff are phosphorus and sediment. Too much phosphorus in lakes and rivers cause algae blooms and too much sediment hurts fish and other aquatic species populations and the overall health of the lake or river. 

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