Stormwater
Why is Stormwater Important?
Today, we know that urban stormwater runoff is the largest remaining contributor of water quality pollution to the urban waterways of the United States. The problem is magnified when development occurs without addressing stormwater pollution, which puts additional stress on the environment. When land is converted from its natural state to one of parking lots, buildings, lawns, streets, and sidewalks, rainwater that once soaked into the ground now flows over the hard, or impervious, surfaces and becomes urban stormwater runoff. The water picks up pollutants such as dirt, fertilizers, pesticides, oil, and bacteria on its way to the nearest storm drain or creek. Unlike sewage, which is collected and treated at a wastewater treatment plant, anything that flows into a storm drain empties directly into the nearest stream or creek, normally without any treatment.
Pollutants in stormwater come from a variety of places, including our cars, streets, parking lots, lawns, construction sites, industrial areas, agricultural areas, pet waste, etc. Because the sources of pollutants are so widespread, the runoff is termed “nonpoint source (NPS)” pollution. Many of our daily activities contribute to NPS pollution and can take their toll on water quality. Typical stormwater pollutants include sediment from construction sites and bare ground, oil and grease from cars and parking lots, fertilizers and pesticides from our lawns, toxic metals from cars, and bacteria from animal waste.