Expert eyes on SA wetlands following River Murray flood
02 February 2023
For the first time in decades the River Murray and its associated wetlands are getting a big drink, following an extended period of high rain volumes falling across the Murray-Darling Basin.
Although the flood waters present a considerable challenge for communities living beside the river, and many industries are feeling the impacts, the water will provide immense ecological benefits.
Monitoring and understanding the environmental impacts
The River Murray is no longer a wild river and needs to be managed to ensure that the river and its wetlands can support the water needs of many states and regional communities while trying to maintain the natural environment and its biodiversity.
The wetlands team from the Murraylands and Riverland Landscape Board is involved in monitoring and managing the health of 87 wetlands (part of 250 wetlands complexes) along the South Australian portion of the River Murray.
The team plans and delivers a program of works to keep wetlands healthy, including delivering environmental water to wetlands (water that is specifically allocated to sustain the environmental health of the river and the flora and fauna that depend on it), or allowing them to naturally dry out.
Darren Willis, who leads the wetlands team of the Murraylands and Riverland Landscape Board, said that it’s going to be interesting and exciting to see how the environment responds to a flooding event that has been so far reaching for such a long duration.
‘Our team is mostly involved in managing the river and wetlands for dry conditions, to sustain the environment between these big drinks,' Darren said.
‘It’s going to be a very special thing to see the extent of environmental response, which should last for several years.’
Information gathered about high river flows and how the environment responds will inform how the positive effects of the flood event can be sustained to capitalise on this once in a generation experience.
While the floodwaters will offer the River Murray and its waterways many benefits, one downside is the increase to numbers of pest species. Carp numbers are already increasing, and management of pest species will be a priority in order to maintain the positive impacts that the influx of water brings.
Supercharged ‘cycle of life’
‘It doesn’t happen very often but these high flow flood events are critical for the large fish species found in the river,’ Darren said.
‘Fish like Murray cod, golden perch and silver perch need high water flows to move through the river catchment to breed and then to disperse the fingerlings that result from successful breeding.
‘The floods are also going to improve the water quality by flushing hundreds of millions of tonnes of salt out of the river system while also recharging the ground water and filling the soil profile.'
‘This will result in a boom in vegetation growth, improve tree health and the quality of the understorey vegetation.'
‘Insects, frogs and fish will breed, and then birds will congregate to feed on them resulting in more successful breeding conditions for birds. It will be a supercharged cycle of life’.
‘This flood event will enable the entire river system to reset which is extremely important as many wetlands are still on the long path of recovery from the millennium drought’.
These videos show the extent of the flood waters in two SA Riverland locations:
Video clip: Berri riverfront - 20 November 2022
Hills and Fleurieu wetlands also benefit from extra water
It’s not just the Murraylands and Riverland wetland team that’s excited.
While not as directly affected by the River Murray flood event, the exceptionally wet season means that in the Hills and Fleurieu region, wetlands and streams that have suffered years of dryer conditions have had revitalising flows which provided ideal conditions for native fish, frogs and invertebrates to breed. Landscapes Hills and Fleurieu has a network of long term ecological monitoring sites and is eagerly awaiting the results from the next round of monitoring.
Contact your local landscape board for project updates and local news about how they are working in your region to care for land, water and nature.
To find your local board visit www.landscape.sa.gov.au.