Dilution flow – December 2021
Freshwater has been released into River Torrens to control blue-green algae in Torrens Lake. Henley South beach users should avoid swimming in discoloured water this week.
Green Adelaide has more information about the flows.
During the summer, beachgoers will be able to receive advice when the water quality at local beaches may not be suitable for swimming.
Beaches in Adelaide are safe and healthy for 98% of the time. However, the water quality at beaches can be impacted by rainfall which flush stormwater into the sea leaving discoloured water especially around drains.
SA Health has advised that people should not swim in discoloured or murky water and through this program beach users will have easy access to current information to enable them to make that decision.
Beach users can sign up to receive alerts by email or SMS specifically for Grange, Henley, Hallett Cove, Christies Beach, Noarlunga or Moana, as these are near the mouths of rivers or creeks, or large stormwater outfalls.
The advice will be sent during periods of poor water quality and swimming should be avoided in discoloured water after rain events for about 72 hours.
Check out the Surf Lifesaving Australia’s Beachsafe app before you visit your local beach for all safety information.
Stormwater flows to the coast by a series of drains that range in size. Not all stormwater drains are monitored. On days when stormwater is flowing to beaches, the water quality may be poor. Beaches on this map will be flagged in real time at locations where stormwater is discharging and potentially impacting on the bathing water quality.
As not all drains are monitored, swimmers should always exercise caution wherever stormwater flowing to the coast and water is discoloured after rain events. Even in times when there is discoloured water after rain, beaches are still open and provide excellent places for land-based recreation.
- Find out where are the monitoring sites
- Find out how you can contribute to reducing stormwater pollution at home
Torrens River dilution flows during summer
Local residents and visitors to Henley Beach and the Torrens Linear Park may have noticed flows in the river for several days during summer months when there has not been any rain.
The Torrens Lake is monitored every summer for blue-green algae levels, and dilution flows are released to control elevated concentrations.
The EPA, Green Adelaide, Department for Environment and Water, SA Water, Adelaide City Council and City of Charles Sturt work together to minimise these algal blooms. We are developing long-term solutions to this problem, although the only reliable short-term management approach is controlled release dilution flows of 150 ML/day into the Torrens River (for up to 4 days).
These dilution flows are only released when there are low levels of blue-green algae detected in the Torrens Lake.
Flows of freshwater into the lake will result in flows downstream to the Torrens Outlet, possibly triggering a beach water alert for Henley Beach.
Flow monitoring data
Stormwater that flows through urban watercourses and onto beaches are continuously monitored by Green Adelaide. To check the water flows at the beaches, click on one of the links below and select the date range you prefer and 'flow' in the parameter box or select raw data. Each monitoring location has a flow rate that triggers a beach alert.
|Beach||Monitoring data||Beach alert flow rate trigger (L/sec)|
|Henley Beach||River Torrens||1,500|
|Glenelg Beach||Brownhill Creek and Sturt River||750|
|Hallet Cove Beach||Field River||500|
|Christies Beach||Christie Creek||750|
|Noarlunga Beach||Onkaparinga River||1,500|
|Moana Beach||Pedler Creek||500|