Reduce your stormwater pollution

By managing your domestic stormwater, you can reduce pollution of the waterways we love to swim in, fish and simply enjoy.

The catchment area of our local rivers and waterways includes our houses, gardens, driveways and lawns. The stormwater system uses the gutters, drains, pipes and rivers to quickly remove water from residential and business areas so as to avoid flooding and the resultant damage this incurs.

When the stormwater system is in use (i.e. during a storm), any litter, debris and other pollution in your yard, gutters and drains will flow, with the water, firstly, into the local wetlands and creeks prior to it flowing into the rivers, bays and the ocean.

Stopping this pollution at its source is essential to maintaining the health of our natural waterways and those communities that enjoy them.

How to do it now!

Ensure that the stormwater leaving your property is free of pollution:

1. Dispose of rubbish such as bottles, cans, chemicals, paints and waste-water properly (see our Recycle technical waste action).
2. Sweep up leaf litter in your driveway and gutters, and use it as mulch or compost on your garden (see Mulch your patch).
3. Consider planting evergreen trees to avoid leaf litter in winter (see our Grow an indigenous garden action).
4. Reduce the amount of fertiliser you use on your garden. Only give plants what they need, using slow release products. Fertilisers can feed dangerous algal blooms if they enter our waterways.
5. Put cigarette butts and other rubbish in the bin and always keep a rubbish bag for rubbish in your car.
6. If water restrictions permit, wash your vehicle on the lawn or a graveled surface. Washing your car in the street increases the likelihood of stormwater pollution.
7. Check your vehicle for oil leaks, as oil leaks will eventually end up in our waterways.
8. Always pick up after your dog. Dog poo left on the ground is often washed into stormwater drains, polluting waterways with bacteria and other harmful nutrients.
9. When painting, make sure you wash water-based paints over grass or sand. Allow left over paints to dry out and then dispose of them in the bin; and never pour paints, solvents or mineral turpentine (turps) down a stormwater drain.

Install and plant a rain-garden

A rain-garden is a garden feature where stormwater can be captured and used. A rain garden can be a depression or planter box (lined) that is accessible from your stormwater system (i.e. house downpipe, driveway runoff or rainwater tank overflow). Water is stored in the rain garden, where suitable plants flourish on the stored water.

The benefits of rain-gardens are they:

• slow the flow of water into stormwater systems reducing the likelihood of flooding.
• filter out pollutants.
• take up excess nutrients that would otherwise end up in the local waterways

A rain-garden can be installed through the following steps:

1. Site selection. Rain-gardens need to be located where they can receive stormwater from your roof, driveway or garden. They should be positioned at least 3 metres away from the house, receive full or partial sunlight and not be over a septic tank system. It is also important that they are positioned to allow excess water to safely flow back into the stormwater system.
2. Site preparation. Natural depressions can be deepened or a trench dug to form the rain-garden. The bottom of the trench or depression is filled with stones (i.e. scoria) and a perforated outlet pipe is layered to allow water inflows in excess of the rain-gardens capacity to be redirected back into the stormwater system. More stones are added to build the storage area up to approx 15cm below the surface. A “weed mat” barrier is placed over the stones and course sand added to fill the pit to the surface. The stormwater source is ideally spread evenly over the area of the rain-garden to ensure rapid and even absorption of water into the rain-garden. For example, down pipes from house roof are perforated to allow dispersal over length of trench.
3. Planting Guide. Drought tolerant plants that can tolerate temporary inundation (water-logging) are suitable for a rain-garden. Your local nursery should be able to advise you on the best local species. Using a gravel mulch will help your rain-garden retain moisture.

Key tips

• Rain-gardens should be fairly free draining, so even major rain events should drain away within a day.
• Avoid compressing (walking on, driving on) your rain-garden as this will reduce it’s capacity to store water.

Further resources

• Office of Environment and Heritage. Provides information on what is stormwater and ways to prevent pollution
• Melbourne Water - Rain-gardens Program
• Sustainable Gardening Australia - Building Rain Gardens

Why is this action important?

The fresh water from our stormwater systems enters our natural waterways where many of us like to swim and fish. Our farmers will often draw fresh water from our rivers for livestock or crops to produce the food we eat. Allowing pollution to enter our waterways can produce toxins (i.e. algal blooms) and introduce chemicals and other pollutants to our lives that are detrimental to our health and wellbeing.

Environment

Taking responsibility to remove pollution that may be washed into the stormwater system will result in our homes and yards being cleaner and less prone to flooding. In addition, this action will directly reduce the amount of pollution flowing into our local waterways and the broader environment.

Wellbeing

Roof water run-off in urban areas contains a range of contaminants, which include heavy metals, nitrogen and chemical pollutants from the air and sediments such as dust, dirt, organic material and animal faeces. Reducing pollution entering our waterways will lower the level of toxins in the food we eat and ultimately us.