Pollution in Rainwater
Rainwater generally contains few chemicals. However, there may be risk of rainwater pollution by airborne contaminants as well as surface contaminants which could include:
Pathogens - microscopic organisms and include viruses, bacteria, fungi and parasites.
Nutrients - from plant matter, fertilisers, car exhausts and gas burning appliances, industrial activities, ash and detergents.
Toxicants - are substances that at certain concentrations are poisonous. They include:
petroleum products, industrial byproducts, biocides (pesticides and herbicides), household chemicals, mercury, copper and other heavy metals.
Suspended Solids - often seen as turbid or muddy and consists of very fine particles. Suspended solids may include soil, organic matter, bacteria and other microorganisms.
Raingardens
Raingardens are a form of bio-filtration that help prevent stormwater runoff from polluting our rivers, creeks and bays.
In Melbourne stormwater collected from roofs, roads and other hard surfaces is directed straight into our water ways without any treatment. This means that any pollution that is carried in that stormwater also enters are waterways.
Soil and plants in the raingarden act like strainers to naturally filter this pollution out of the stormwater before it re-enters are water ways. They are a low cost simple and effective solution to decreasing stormwater pollution.
Design of Raingardens
Raingardens can be designed to have many different looks. They can look identical to the surrounding landscape are they can specifically be designed to look different to the surrounding landscape. In many instances you may want the Raingarden to stand out - especially if it is going to be used as an educational resource such as in our projects at Armadale Primary and Clifton Hill Primary Schools.
Generally the Raingarden consists of 3 different layers of specially designed filtration media with slotted pipe located at the base of the area to collect the treated water and return it to the stormwater system.
Scale of Raingardens
Raingardens can be designed at any scale. They can suit a courtyard garden or a carpark.
We use a software program designed by Monash University to model all of our Raingardens projects. This means we can tell you how much pollution you will be removing from the system before we implement it.
If you would like to incorporate a raingarden into your garden design just contact us.