What is urban runoff and stormwater pollution?
Stormwater runoff refers to seasonal rainfall flows. It is very noticeable during a heavy rain when large volumes of water drain off paved areas. Urban runoff can happen anytime of the year when excessive water used for irrigation, car washing or cleaning carries litter, lawn clippings, dirt, debris and other urban pollutants into storm drains. Even an automobile leaking motor oil 20 miles inland can still pollute the ocean.