Stormwater management is essential to protect lives, assets, and the environment. Find out about the Shire’s requirements for managing stormwater on residential and commercial properties.
Responsibility for managing stormwater
In the Shire, about 1m of rain falls on each square metre of land per year. For the average residential lot this equates to about 700,000 litres of water that must be controlled.
It is the responsibility of the property owner to manage and control stormwater from buildings and surface water run-off on their property.
The Building Code of Australia (BCA) has standards in place to protect a building from water damage.
Residential stormwater requirements
In clay soils in newer urban areas, there is a stormwater system available to help with stormwater management.
Where there is no available stormwater system to connect to
You will need to provide 1m³ of on-site storage for every 100m² of impervious surface, which is the total area of all roofs, paving and driveways. As a guide, a 900 x 900 soakwell will hold about 0.5m³.
Where a stormwater connection system is available
The landowner must provide a silt trap on the property side of the connection point.
Gutters and downpipes need an overflow relief in the event of a blockage in the stormwater system. The gutter may be designed to prevent flooding, and downpipes should not be directly connected to the stormwater pipes below ground without some means of escape.
Subsoil drains are required to be connected to the stormwater disposal system. These pipes must work efficiently to ensure the structural integrity of your house. Therefore, maintenance is essential.
Paving around the house needs to be a minimum of 50mm below the house floor level and must slope down a minimum of 25mm in the first metre away from the building. Some paving areas may also need to be connected to a drainage system, depending on the landscape.
Driveways that fall towards the street need to have a stormwater grate at the edge of the property to catch run-off.
Commercial stormwater requirements
Commercial developments need to manage stormwater on-site. Because of their large impervious surface areas, the system design will usually need to be slowly released to the street system, where available, through a slow-release silt trap. Such a design would usually require a professional consultant or engineer.