Urban Storm water management through bioretention swales in Institutional campus for Green Environment - A Case Study

Nature uses vegetated depressions, wetlands, marshes, etc. to clean storm water runoff by removing sediments, turbidity, heavy metals, and other pollutants. Some pollutants are removed by vegetation uptake, some by natural flocculation from decomposing vegetation, some by just slowing the flow down enough for sedimentation to occur, and some by biota consumption and ionic attraction around the root structure. Many pollutants migrate attached to soil particles and soil particles in themselves are considered a pollutant. When storm water runoff leaves a site, unless there is effective erosion protection such as vegetation, soil also leaves the site, in the forms of sediment, suspended solids, and microscopic soil particles called colloidal suspension, dissolved solids, or turbidity. The soil particulate can be clay, minerals, organic material, heavy metals, etc. Sediment usually will readily settle out.A biological filtration canal is a shallow depression created in the earth to accept and convey stormwater runoff. A biological filtration canal uses natural means, including herbaceous vegetation and soil, to treat stormwater by filtering out contaminants being conveyed in the water.