Stormwater
What is stormwater and why is it important?
Managing Rainwater Runoff
The leading cause of water quality problems today is from polluted stormwater. Unlike pollution from industrial and sewage treatment plants (which is more easily controlled), this type of pollution, also known as nonpoint source pollution, or NPS, comes from a variety of human activities on the land. It's the main reason that approximately 40% of the nation’s rivers, lakes, and estuaries are not clean enough to meet basic uses such as fishing or swimming. Each of us contributes to the problem without even realizing it.
Pollutants
NPS pollution is caused by rainfall moving over and through the ground. Paved surfaces like driveways, sidewalks and streets prevent rainwater from naturally soaking into the ground. Rainwater can pick up:
- Fertilizers, herbicides and insecticides from agricultural and residential areas
- Oil, grease and toxic chemicals from urban runoff
- Sediment from improperly managed construction sites
- Bacteria and nutrients from livestock, pet wastes and faulty septic systems
- Atmospheric deposition and hydromodification
These pollutants can then flow into a storm sewer system or directly to a lake, river, or wetland, and eventually to the Pacific Ocean.
