The Grange Lakes system is primarily ephemeral – meaning it is intended to hold stormwater during winter and dry out when water is not available.
To further provide environmental benefits and improved amenity during periods where the system is dry, Charles Sturt and the Adelaide and Mount Lofty Ranges Natural Resources Management Board (AMLRNRMB) have worked collaboratively to install a diversion pump in the River Torrens – with an associated licence which allows us to divert 350 million litres into the Grange Lakes System in conjunction with a release of water (‘Environmental Flow’) from the Torrens Lake.
River Torrens Environmental Flows occur at the discretion of the AMLRNRMB and are to maintain water quality in the Torrens Lake system. These releases are strictly controlled by water quality testing undertaken by the Department for Environment and Water and occur only where necessary.
Unfortunately, during some periods, there has not been a justifiable reason to release water and therefore the Grange Lakes system has dried.
In order to look after the Grange Lake system, during appropriate times, we excavate to remove sediment and maintain areas of flora to protect the system’s environment. We maintain vegetation within the Grange Lakes System for both amenity and habitat purposes and this vegetation has adapted to the ephemeral conditions associated with the Lakes. We continue to monitor both planted and invasive species (such as the commonly known Typha) to balance the amenity of the reserve and Lakes system.
During dry periods, our birds will seek refuge in alternative water bodies, such as Fresh Water Lake, Cooke Reserve and the Port Road Wetlands. Wetland birds rely on wetlands and waterways for survival and have evolved numerous adaptations to these environments. Each bird species has its own requirements for food, shelter and breeding sites which influence its use of the wetland.
We have worked collaboratively with the AMLRNRMB to divert water from the River Torrens when the Environmental Flows have been released to clear algal bloom from the Torrens Lake. Based on our experience in previous years, it is evident that we cannot rely on this flow every year. Consequently we will make future budget submissions to Council to permanently deepen pools and install shallow marsh areas and rocky banks and provide additional plants to improve habitat and amenity.
Council has considered options associated with providing additional water to the system, however, for both cost and environmental reasons, this is not considered feasible.
For further information on the Grange Lakes System and the investigations we intend to make for the future of the system, please read our FAQs below or contact our Customer Contact team. We understand the importance of the Grange Lakes to our residents, and we look forward to the cooler months bringing much needed rain into the system.
Please read our Frequently Asked Questions:
The Grange Lakes system is primarily ephemeral – meaning it is intended to hold stormwater during winter and dry out when water is not available.
It is however important to recognise the history of our urban area and the impact of changes we have made to our environment. Prior to urban development, the West Lakes and Grange area hosted a natural wetland associated with the River Torrens. Formerly, the river flowed northwest toward the Port River, but the sediment picked up in the uplands choked the channels and the Torrens was diverted to the west migrating laterally before eroding its present channel, creating swamps, marshes and, notably, the ‘Reedbeds’ behind the sand dunes which front the coast, before draining north to the Port River or south to the Patawalonga.
During the first century of settlement, considerable time and money was expended on attempts to control the river and the problems it posed, especially for the areas west of the city. A direct outlet to the sea was excavated through the coastal sandhills at West Beach, channels were straightened and cleared, and the flood danger mitigated with the construction of dams, and especially the Torrens Dam (or weir) west King William Road in the city in 1881, behind which was formed the Torrens Lake.
Since these management techniques were implemented, natural flows have changed and the increase in urban development has required the management of stormwater. This has resulted in the construction of the Grange Lakes stormwater system, which collects stormwater from the Henley Fulham catchment. This system is primarily ephemeral – meaning it is intended to hold stormwater during winter and dry out when water is not available. To further provide environmental benefits and improved amenity during periods where the system is dry, Charles Sturt and the AMLRNRMB have worked collaboratively to install a diversion pump in the River Torrens – with an associated licence which allows us to divert 350 million litres into the Grange Lakes System in conjunction with a release of water (‘Environmental Flow’) from the Torrens Lake.
River Torrens Environmental Flows occur at the discretion of the AMLRNRMB and are to maintain water quality in the Torrens Lake system. These releases are strictly controlled by water quality testing undertaken by the Department for Environment and Water and occur only where necessary.
Unfortunately, during some periods, there has not been a justifiable reason to release water and therefore the Grange Lakes system has dried.
Further information can be found here.
The City of Charles Sturt’s water allocation licence only allows us to pump water into Grange Lakes in conjunction with a release of water (‘Environmental Flow’) from the Torrens Lake. Unfortunately, during some periods, there has not been a justifiable reason to release water and therefore the Grange Lakes system has dried.
The City of Charles Sturt normally plans to excavate sediment in parts of the system after an environmental flow is undertaken.
Some summer periods do not require environmental flows during these years sediment removal will usually occur prior to first major winter rain.
Environmental flows are events strictly managed and controlled by the AMLRNRMB and aim to mimic natural flow patterns in the Torrens, South Para and Onkaparinga rivers. There will be periods of no flows, low flows and high volume flushes, as would have happened under natural conditions. Environmental flows, are carried out during the summer period when the Blue Green Algae in the Torrens Lake reaches levels significantly impacting human health.
We periodically send crews into the area to remove rubbish along the dry sections of Grange Lakes. If you have concerns in a particular area please contact our customer service team and raise a Customer Request.
We are in a holding pattern until water is released from the Torrens Lake or until a natural rainfall event occurs. We have no other water available to us. We do continue to work closely with the AMLNRMB to understand when an environmental flow is to occur, so we may divert the maximum amount of water available to us and replenish the Grange Lakes system.
We maintain vegetation within the Grange Lakes System for both amenity and habitat purposes. Much of the vegetation has established over the years and adapted to the ephemeral conditions associated with the Lakes. We continue to monitor both planted and invasive species (such as the commonly known Typha) to balance the amenity of the reserve and Lakes system.
During dry periods, our birds will seek refuge in alternative water bodies, such as Fresh Water Lake, Cooke Reserve and the Port Road Wetlands. Wetland birds rely on wetlands and waterways for survival and have evolved numerous adaptations to these environments. Each bird species has its own requirements for food, shelter and breeding sites which influence its use of constructed and natural water bodies.
Feeding birds too much artificial food may not provide adequate nutrition which can lead to health problems. An example is the feeding of bread to ducks. This might seem like a treat but it lacks nutrients that they would normally obtain from their natural diet of insects and fish.
Problems can arise if the adult birds raise their young on this diet as the juvenile birds can suffer from brittle bones. Feeding bread to birds (even ducks!) can cause problems with their digestive systems as the bread ferments in their stomachs and honey/water mixes do not provide the complex sugars that a bird would get from the nectar of a flower. Further, processed meats are high in salts, fats and preservatives. Magpies fed items like fritz have been shown to have high cholesterol.
We recommend you don't feed birds artificially but preferably plant up your garden to attract birds, as it is much healthier for birds to glean natural food from your garden. If you feel you must feed the birds, small amounts of seed or salad greens are advised.
Concerns have been expressed around the potential for trees to die or drop branches as a result of the extreme weather. We periodically undertake a general assessment of the trees within the Grange Lakes corridor to determine if this is a concern and further action required.
A decision was made by Council in November 2016 (CL 28/11/2018 Item 6.153) as per the below:
3. That Council accepts the pump infrastructure donated by the AMLNRMB to assist with Grange Lakes environmental flows.
4. That Council support the diversion of River Torrens water through the Grange Lakes system at times of the environmental flows as determined by the AMLNRMB.
Unless the water is made available by State agencies we are unable to act on these recommendations. In its developed state, without the opportunity for diversion, the Grange Lakes system is ephemeral – meaning that it will dry out when rainfall and stormwater is not channelled into the system.
West Lakes is a tidal lake and this causes backflow up the drain, added to this the trash collectors require pressure from outgoing water flow to hold the rubbish within them. Please let us know if an excessive amount of rubbish is within the drain and if safe we will have it removed.
Yes, the drainage team inspect the trash collectors frequently throughout the year and notify of any damage. It is important to understand that during extreme rain events water can bypass the collection system to allow flow, this is to minimise flooding within the catchment.
If anyone has any specific requests they should be logged through our customer care team.
These requests can also be logged via the free My Local Services app which includes photos that assists greatly to plan the correct teams to the specific issue.
A Stormwater Management Plan (SMP) for West Lakes stormwater catchment is underway (a very large area including suburbs of Henley Beach, Fulham Gardens, Grange, Seaton, Findon, Woodville West, West Lakes, Semaphore Park) and the Grange Lakes is located in the catchment.
SMP will look in to opportunities for flood mitigation, water quality improvement and harvesting at various locations in the catchment including in the Grange Lakes corridor.
A draft SMP with options and costing for CCS officer review is expected in June – July 2021 following which
- it will be provided to other government entities (Green Adelaide, DIT, EPA, DEW, SES) for comments
- The Draft SMP will be updated and presented to Exec and Council
- Public consultation