Stormwater and the environment
The stormwater system is designed to take rainwater from our streets and guttering into the closest waterway. Unlike sewage, stormwater is not treated before it enters our waterways. In some cases it is filtered by traps or wetlands, usually located at the end of the pipe system, but in most cases it flows directly from our streets and gutters into our creeks, rivers, bays and the ocean.
Maintaining our water quality is a challenge we all play a role in. Please do not empty any contaminants into the system, such as paints, oils, poisons or fertilizers. This has a devastating impact on aquatic flora and fauna.
The City is working with the community to improve the quality of our stormwater through wetlands, frog ponds and new ultrasound technology to eliminate toxic algae, biofilms and bacterial pathogens from our lakes.
The City is becoming a Water Sensitive City (WSC) that recognises the importance of water in supporting urban liveability, sustainability and resilience. More information can be found at: Water Sensitive Bendigo
The City has a guideline on Water Sensitive Urban Design that provides supporting information to consider in different stages of developments related to stormwater quantity and quality. The guide can be found at: Water-sensitive-planning-and-construction
Urban areas have constructed hard and impervious surfaces like roads, driveways, car parks, roofs and paving. When stormwater run-off flows over these hard surfaces, it readily accumulates pollutants. Stormwater pollutants originate from many different sources including fuel and oil on our roads, excess fertilisers and soaps from cleaning, litter dropped on our streets and sediment from building sites.
Improving stormwater quality in the long term will require effective prevention and management of these pollutants at their sources, as well as treatment of stormwater before it enters our waterways.
In urban areas, the increase in the number and size of impervious areas has reduced the amount of rain that infiltrates the ground or is retained by vegetation. Consequently, more stormwater run-off enters the drains system and receiving waterways.
Urbanisation has also changed the rate of stormwater discharge into water environments. Stormwater drainage systems have usually been built to remove stormwater from urban areas as quickly as possible, to minimise the risk of flooding and prevent water stagnating. The increased volume entering waterways causes scouring (in-stream erosion) of waterways. In less modified catchments the run-off water is released over a longer period of time, which maintains healthier water environments.
Reducing stormwater run-off can be more difficult in well-established urban areas that have a high density of buildings and infrastructure. However, new developments and the redevelopment of some urban areas are moving to incorporate measures that increase stormwater infiltration and reduce adverse impacts on our waterways. For example, grass swale drains, vegetated filter strips and porous pavements allow more stormwater to soak into the ground. We can also protect stream habitats and restore creeks that were previously modified (by channelling), by incorporating meanders, pools and in-stream vegetation.
Measures designed to improve stormwater quality and quantity can complement objectives of public safety and local flood protection.
More information on stormwater and the environment is available here:
The creation of artificial lakes and wetlands in new urban developments is part of a new design concept referred to as ‘water-sensitive urban design' (WSUD).
The traditional approach to urban stormwater management has been to collect runoff and channel it within closed underground pipes and discharge the channelled water into natural receiving waterways with little, if any, treatment prior to discharge.
The basic aim of WSUD is to protect and enhance our natural waterways in urban catchments by reducing pollution in stormwater runoff. Additionally, recycling the water within our properties is seen as ecologically responsible and hopefully a cost-effective use of a scarce resource.
Water-Sensitive Urban Design re-defines water management and conservation in a practical way. Designing new housing and other developments to incorporate WSUD is about ensuring that water, as a resource, is used as efficiently as possible. So instead of simply removing water from a site without treatment, and creating water quality and quantity problems downstream, water should be stored, reused and treated at every possible opportunity. This helps to create more sustainable developments.
Landscape elements of WSUD, which feature in many new developments include:
- Grass swales (drains)
- Bio-retention drains
- Treatment wetlands (artificially constructed)
- On-site storage systems (above and below ground storage tanks)
- Porous or permeable paving in car parks
The different elements of water-sensitive urban design are usually integrated throughout the development area (often more than one allotment or a new suburb) in a combination known as a 'treatment train'. This involves constructing stormwater treatment devices at locations where the stormwater is collected, channelled and discharged. The selection of treatment options should be based on the removal of pollutants from the surrounding land. Pollutants may include sediment, hydrocarbons, organic materials, heavy metals, pesticides or nutrients (from fertilisers)
Model for Urban Stormwater Improvement Conceptualisation (MUSIC) guidelines
Water Sensitive Bendigo
Check out our journey : Water Sensitive Bendigo
WSUD Resource Kit
For more information about stormwater and the environment, please contact our Engineering unit on 03 5434 6000 or [email protected]