A significant source of pollutants that collect in principal waterways – streams, rivers and bays – is storm water runoff that originates in local residential neighborhoods and commercial and industrial workplaces.
There are three main types of storm water pollution:
Litter, such as cigarette butts, cans, paper or plastic bags
Chemical pollution, such as detergents, oil or fertilizers
‘‘Natural” pollution, such as leaves, garden clippings or animal droppings
These compounds end up discharging into waterways as sediment, sludge and solids. These can be caught in pollution traps, but the most effective way to reduce this problem is to prevent pollution entering the storm water system in the first place. The traps don't catch all the silt or litter, and they don't stop chemicals.
Who's responsible?
Everyone has a part to play. Reducing the pollution depends on every person doing what they can to prevent harmful natural or chemical substances from entering storm water drains.
Local water districts are responsible for controlling and maintaining storm water systems. However, it is everyone's responsibility to reduce the amount of rubbish and pollution that is carried into the drains.
Local water authorities and rate-payers have to foot the bill for cleaning out pollution traps, and it is much more cost-effective to stop the problem at the top of the pipe rather than further downstream.
The quantity and severity of storm water pollution are affected by:
When it last rained and the intensity of the rain
Building density and other land uses in the catchment area
Level of vegetation cover
Cleanliness of the streets
Local practices, such as street sweeping, pet control, garden watering, or use of chemicals.
Pollution at home and in your street
Typical activities that can cause storm water pollution are:
Car washing on the street: using detergent and allowing it to run down the street drain.
Fixing your car on the street: letting oil or other substances flow into the street drain.
Disposing of garden waste: letting leaves or garden clippings accumulate in gutters.
Dropping litter: dropping litter where it will be swept into the street drains next time it rains.
Cleaning paint brushes: letting the contaminated water flow into the street drain.
Hosing the footpath: letting the water carry dirt, soil or other waste into the street drains.
Not picking up dog droppings: left dog droppings will be carried into the storm water system next time it rains. (Imagine the cumulative effect of all the dogs in your neighborhood.)
Typical activities at work that can cause storm water pollution are:
Restaurants: not cleaning out the grease trap regularly.
Motor vehicle repairers or printers: letting oil, chemicals or other waste flow into the street drain.
Builders: not shielding street drains from spilt chemicals or excess soil, sand, gravel or other building waste.
All work places: letting cigarette butts or litter fall into gutters or on driveways; letting chemicals, detergents or other harmful fluids run into street drains.
Compounded effects
Storm water pollution can kill plants and animals that live in the water. For example, sediment in the water reduces light penetration and affects photosynthesis, the process that allows plants to use light as their source of energy.
When green waste decays in water it uses up oxygen, taking vital oxygen away from plants, fish and other aquatic animals. Suspended soils make waterways cloudy and can suffocate fish by clogging their gills.
Finally, litter clogs waterways and causes toxicity as it breaks down. It affects the health of birds, fish and other animals and plants that live in the waterways.
All efforts by communities and individual citizens to monitor and control the flow of storm water – and the elements it carries – are important first lines of defense in a comprehensive environmental protection program intended to keep our waterways clean.
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