Learning & resources
Water sensitive urban design (WSUD)
Water-sensitive urban design (WSUD) promotes the sustainable use and reuse of water integrating water from all sources. WSUD is an approach to urban planning and design that integrates the total water cycle into the urban development process.
- integrated management of groundwater, stormwater, drinking water and wastewater to protect water related environmental, recreational and cultural values
- the storage, treatment and use of stormwater
- treatment and reuse of wastewater
- the use of vegetation for treatment purposes, water efficient landscaping and enhancing biodiversity
- using water-saving measures within and outside domestic, commercial, industrial and institutional premises to minimise requirements for drinking and non-drinking water supplies.
Source: WSUD Technical manual for Greater Adelaide, NWC.
WSUD techniques can reduce stormwater flows and improve the water cycle so it mimics a more natural water cycle.
When WSUD is implemented appropriately it can greatly reduce the impacts of urbanisation including those from stormwater. A range of WSUD measures may be used to reduce the impacts of stormwater pollution and changed flow regimes, depending on site circumstances as illustrated.
Some WSUD techniques are outlined below. For a more comprehensive overview see WSUD Technical Manual Chapter 1 Introduction to WSUD.
The best way to minimise our impacts and to help prevent stormwater pollution are to minimise the amount of stormwater that leaves your property.
Rain gardens and green roofs (infiltration systems) help manage runoff at the sources, mimicking a more natural regime and allowing potential runoff to infiltrate the ground recharging groundwater and reducing runoff. Rain gardens and green roofs are both vegetated systems which help treat the runoff through removal of sediment and attached pollutants and the uptake of nutrients by the plants.
Further information on how to build a rain garden: How do I build a raingarden?.
Further information on the range of infiltration systems: WSUD Technical Manual for Greater Adelaide Chapter 6 Infiltration Systems.
Pervious pavements are load wearing pavements that may be incorporated in driveways and paths. A pervious pavement is made of a surface layer that allows water to penetrate to an underlying storage layer. The storage layer consists of crushed stone or gravel which is used to store water before it infiltrates to the underlying soil or it may be discharged towards a piped drainage system. Infiltration to the ground assists in reducing runoff, recharging groundwater and there is some removal of sediment and any attached pollutants through the gravel layer.
Further information on the range of pervious pavements in Chapter 7 of the WSUD Greater Adelaide Technical Manual Chapter 7 Pervious Pavements.
Rainwater tanks are designed to capture and store water from a roof of a building. They may be plumbed into the house and used for a range of purposes such as toilet flushing, laundry or garden irrigation. Depending on the size and usage they can greatly reduce the runoff from a property. Further information on rainwater tanks in WSUD Greater Adelaide Technical Manual Chapter 5 Rainwater Tanks and SA Health Rainwater Tanks Care & Maintenance.
Demand reduction water efficient fittings and appliances will also help reduce demand of potable water and should be considered around your home. See WSUD Greater Adelaide Technical manual Chapter 4 Demand management.
WSUD can effectively be applied to the non-work areas of commercial, industrial or retail sites to minimise impacts on the natural water cycle. It may not be suitable for work areas, but could form part of a treatment train, depending on the activities being undertaken.
Separation of work areas from other parts of the site is key to ensure pollutants from the activities do not contaminate the stormwater. If this is done robustly it will isolate the industrial pollutants potentially minimising the cost of treatment. By roofing work areas it removes large volumes of water which can be used for other purposes and reduce the demand for potable water.
Although at risk of some contamination from vehicle movements, sediment and litter, the further separation of areas such as carparks, administration areas and some roadways from both water from the roof and work areas mean that these areas can usually be treated similarly to other urban stormwater, using a range of best practice WSUD measures.
Bio-retention may be suitable for driveway areas of commercial and industrial sites.
Bio-retention (biofiltration) systems are systems that improve stormwater quality through vegetation and filtration through a prescribed filter media. Treated flows are either infiltrated to underlying soils, or collected in an under-drain system to the stormwater system. They may be located in carparks, along roadways or in median strips and hence are usually suitable for these locations on a commercial or industrial site. The surface area should be sized at a minimum 2% of the contributing catchment size.
Further design and technical information on biofiltration systems refer to:
- Facility for advancing water biofiltration (FAWB) stormwater biofiltration systems adoption guidelines
- Water By design bioretention technical design guidelines
- WSUD Greater Adelaide Technical Manual – Chapter 10 Bio-retention systems
Constructed wetlands are shallow, extensively vegetated water bodies that allow settling of sediment particles, fine filtration and biological processes to remove pollutants. Constructed wetlands may be useful where runoff contains high concentrations of soluble material but this will require careful design with large macrophyte zones and extended residence time.
- Chapter 13 of the WSUD Greater Adelaide Technical Manual
Melbourne Water 2010, Constructed wetlands guidelines
Pervious pavements are load-bearing pavements that are permeable to water. They include a permeable surface layer that allows water to penetrate to an underlying storage layer. The storage layer consists of crushed stone or gravel which is used to store water before it infiltrates to the underlying soil (or it may be discharged towards a piped drainage system). Infiltration to the ground assists in reducing runoff, recharging groundwater and there is some removal of sediment and any attached pollutants through the gravel layer. The suitability or otherwise of pervious pavements will depend on the activities of the business.
Further information on the range of pervious pavements see WSUD Greater Adelaide Technical Manual Chapter 7.
Water efficiency in your business can help reduce costs and your environmental footprint. Rainwater tanks designed to capture and store water from a roof of a building can be employed and captured water may be used for a range of purposes within the business. Depending on the size and how they are utilised they can greatly reduce the runoff from a business.
Reducing runoff assists in reducing changes to the flow regimes that urban waterways and coastal waters, usually experience, thereby reducing impact. Use of captured rainwater may be one of the demand reduction strategies employed by the business. SA Water can provide assistance to business in developing water efficiency plans and have a Water efficiency toolkit available.