Effects of Stormwater Pollution
Any rain that falls on the roof of your house or collects on paved areas like driveways, roads and footpaths is called stormwater. As stormwater travels over the land, it picks up all kinds of chemicals and materials that are not naturally found in our waterways. Some of these are toxic and dangerous - even in small amounts. Others, such as nutrients, are not poisonous but may be produced in such great quantities that natural systems simply can't cope with their impact. After a dry season, the first flush of stormwater can have the same pollutant load as raw sewage. This results in the pollution of our waterways.
Factors affecting stormwater pollution
The amount of stormwater runoff produced and pollution levels are affected by:
- when it last rained
- intensity of the rain
- building density and other land uses in watershed areas
- level of vegetation cover
- the cleanliness of the streets
- local practices such as street sweeping, pet control and excessive garden watering.
The effect of stormwater pollution
The effects of stormwater pollution include killing plants and animals that live in the water. For example:
- sediment in the water reduces light penetration and affects photosynthesis, which is the process that allows plants to use light as their source of energy
- litter clogs waterways and causes toxicity from the breakdown of material and has an effect on the health of birds, fish and other animals and plants that live in the waterways
- organic material (green waste) uses up vital oxygen in the water
Effects of Urban and Rural Development
As our community grows, so does the need to take care of our environment . When new suburbs are created, the stormwater run-off increases from 5% to over 50%, and as much as 98% in fully built up areas.
The original creek network is often unable to cope with the enormous amount of extra water, and this contributes to flooding damage. Stormwater run-off also contains a large number of pollutants.
Rural Development
Irrigation for agriculture and horticulture, grazing stock, spraying chemicals and fertilizers, and dam construction all impact watersheds.
Common Pollutants
Pollutants have many origins - here are just a few:
- Vehicles - cars and trucks that drip oil and grease onto the road are a source of pollution, so too is the rubber that gets worn from the tires and deposited on the road surface. The next time it rains, have a look at the quality of the water running in the gutters, you will probably notice the water has an oily film on it and water can be far from clear in color.
- Chemicals and paints - used around the home and office can also become pollutants if they are not disposed of properly.
- Chemical pesticides and fertilizers - used on the garden can also be harmful if they are washed into local creeks and rivers via the stormwater system. For this reason it is wise to use pesticides and fertilizers sparingly and to avoid using them at all on a windy day.
- Plant litter - grass clippings and the leaves of non native trees can also be very harmful to aquatic ecosystems.
- Litter - trash dropped by people is a real problem.
Aren't businesses bigger polluters than residents?
Both industry and the community have an important role to play in helping to reduce stormwater pollution. Strict pollution controls on industry have helped reduce their impact on the environment in recent years. Cleaner production and business practices are encouraged to reduce stormwater pollution.
The reality is that we all have an impact on stormwater quality, and we can all take steps to make a difference.
