Open land undisturbed by human activity has minimal surface runoff. Rainwater soaks into forest and grassland areas, since living plants act as "natural sponges" for rainfall. Sediment is trapped and dissolved pollutants may be slowly broken down by natural soil bacteria in these habitats, keeping the pollutants out of our surface and ground water. Stormwater pollution becomes a greater concern as areas become more urbanized.

NC Cooperative Extension offers educational information to help private citizens, businesses, and government agencies reduce or eliminate stormwater pollution. Research demonstrates that runoff and pollution from a property increases as the amount of impervious surface area on that property increases. Roads, driveways, parking lots, buildings and ground compacted from vehicles and heavy equipment are examples of impervious surfaces commonly found in cities and towns. Water cannot penetrate through these surfaces, and must be diverted to prevent flooding. Gravel surfaces, cement, and asphalt are all examples of impervious surfaces.

Most cities have an intricate drainage system to handle stormwater and minimize flooding. Contrary to popular belief, the water that flows into storm drains is not sent to a waste treatment plant. Rainwater transports the pollutants to open waterways through the storm drains. The initial runoff, or first flush of rainwater, is the most contaminated. Pollutants accumulate on impervious surfaces when it has not rained for a long time. Common stormwater pollutants include gasoline residue, used motor oil, trash, lawn fertilizers and pesticides, and sediment.

Private citizens can reduce stormwater pollution by practicing the following tips:

• Keep natural areas undeveloped.
• Bring oil, antifreeze, and other contaminants to the Household Hazardous Waste disposal collection sites instead of pouring them onto driveways and streets or into storm drains.
• Plant vegetation that will deter erosion, especially on slopes or along streams.
• Use all house and garden chemicals according to directions. Do not over-fertilize.
• Repair oil and coolant leaks on vehicles promptly.
• Keep our cities and rural areas beautiful--do not litter.

Click here for more information on one NC city's stormwater pollution reduction efforts.