Stormwater is the same as rain water or snowmelt plus anything it “picks up” after it hits and flows along the ground. Impervious areas such as streets, parking lots, driveways, and rooftops create more stormwater runoff because rain can’t soak into the ground. The more impervious area there is, the higher the amount of stormwater runoff. This is why populated areas often experience more flooding than rural areas. This doesn’t mean that rural areas won’t flood, however. Stormwater can also come from pervious areas such as lawns and planting beds. Such areas will absorb some rain, but runoff will still occur from them if they’re compacted, have become saturated, or if there’s heavy rain.
Unlike sanitary sewage, most stormwater is not treated. It flows across the ground, into storm drains, pipes and ditches, and then directly into streams, ponds, lakes and rivers. Stormwater is often polluted with sediment, bacteria, nutrients, heavy metals, chemicals, and many other pollutants that are left or dumped on the ground and in the path of stormwater runoff. Stormwater pollution can be controlled if everyone plays a part in keeping pollutants off the ground and out of our stormwater systems’ drains and pipes. Please read on to learn more about stormwater pollution, its impacts on our waterways, and what you can do to prevent pollution.