Rainfall or other forms of precipitation. Storm water runoff is the result of storm water washing across impervious surfaces, carrying with it the pollutants found on streets, parking lots, rooftops, etc. These pollutants end up in streams and rivers. Storm water runoff contributes from 60 to 80% of total water pollution.
Rain and snow runoff from the urban landscape, primarily impervious surfaces. Storm water often transports water pollutants such as heat, bacteria, litter, suspended solids, nutrients, metals, and organic chemicals. Sources of these pollutants include warm pavement, pet waste, construction site erosion, road salt and sand, lawn fertilizer, shingles and gutters, gasoline, oil, and antifreeze. The quantity of storm water runoff from impervious surfaces is also a problem, causing stream bank erosion and destruction of habitat for fish and other stream biota.