Storm is known for a heavy fall of rain, snow, or sleet often with strong winds. When storm comes it brings large quantities of precipitation, that is rain water or snow/ice melt, and this known as “stormwater.” This water in due course flow over natural landscape or man made impervious surfaces, like paved parking lots, streets, roads and other areas known as “stromwater runoff.”

Stormwater runoff, in natural landscape areas, where grass, plants and soil absorbs much of the water. In other words, most of the stormwater infiltrates into the ground, and as result not only the runoff rate will be reduced, but groundwater table and the local streams and rivers water level will be increased, which ultimately becomes an important natural resource required to survive for all the living beings on this planet.

However, in the impervious surface (parking lots, streets, roads, buildings, compacted soil) areas, especially in Urban region, stormwater runoff creates not only flooding but also picks up anything it can on its way from higher to low level areas. Especially, during a rainstorm water is flushed out from impervious surface areas as a result most of the pollutants will be carried out and finally enter the waterways.