Water is essential for life. It is our most precious natural resource. Surface waters - such as lakes, creeks, and rivers - can easily become polluted. Both point and non-point sources contribute to water pollution. Storm water runoff comes from many diffuse (or non-point) sources. The U.S. Environmental estimates that at least 50 percent of our nation's water pollution is Protection Agency caused by storm water runoff.
When it rains or snow melts, runoff picks up and carries a wide variety of pollutants into our storm water system. These pollutants then flow into our local waterways - and on to the Gulf of Mexico. Some examples of storm water runoff pollutants include:
Detergent, fertilizer, pet waste, and yard waste such as leaves, grass clippings, and pine needles
These substances contain nutrients - one of the greatest pollution problems affecting water quality. The nutrients nitrogen and phosphorus not only cause grass to grow, but an excessive amount also causes algae to grow in our waterways. Algae blooms cause fish kills and block sunlight for the underwater vegetation needed by fish and shellfish for food and cover. Pet waste, like human waste, is also disease-carrying raw sewage. Raw sewage in our waterways can make water unusable for fishing, swimming, and drinking.
Automotive products such as motor oil and antifreeze; hazardous waste such as cleaners and paints; and pesticides (herbicides, insecticides, fungicides, odenticides)
These materials are toxic, so they are harmful to humans and animals as well as the environment. Antifreeze is a particular hazard to pets, which may drink from contaminated puddles. Toxics in our waterways can make water unusable for fishing, swimming, and drinking. In Iowa, many of our surface waters are used as drinking water sources. Four quarts of motor oil can create an 8-acre oil slick and contaminate millions of gallons of drinking water.
Yard waste and litter
These items decompose in water, removing oxygen needed for aquatic life. Yard waste can also clog the storm water system, contributing to street flooding. Litter often ends up floating in waterways or washing up on banks and beaches. Plastic litter endangers marine animals, which eat it mistakenly as food or become entangled in it.
Sediment (soil, sand, silt, clay)
Sediment from non vegetated areas clogs fish gills, blocks sunlight for underwater vegetation, and smothers shellfish and fish-spawning areas. It is the largest contributor of storm water pollution by volume.