Urgent action is needed to avoid a NSW water crisis in the aftermath of this summer’s devastating bushfires, experts warn.

Significant rainfall that’s expected across NSW over the coming days will wash sediment, ash and nutrients into the state’s waterways.

Charles Sturt University Professor Max Finlayson says minimising the impact on vital water supplies and waterways needs to be a priority to avoid water quality issues, toxic algal blooms and further fish kills.

“For many places we still need to focus on post-bushfire recovery but we need to start looking at catchments, waterways and wetlands in the medium-term as a matter of urgency to avoid long-term implications,” Prof Finlayson told AAP on Thursday.

“In the long-term, we could have some real biodiversity concerns and serious water quality issues.”

Prof Finlayson said algal blooms can be toxic and make water unusable for people. Native fish populations could be decimated in waterways.

“Huge areas of the Nymboida and Mann river catchment have been burnt and these rivers are critically important habitats for the endangered eastern cod,” he said.


“In the worst case, we could end up losing fish species.”

Flood run-off could affect water supplies in dams on rural properties. Bushfires have already had a devastating impact on stock and this could add to landholders’ woes.

Prof Finlayson says minimising erosion is the key through the use of sediment traps, geo-fabrics, logs or straw bale barriers.

However, he acknowledges the high scale of the bushfires crisis could make implementing such strategies difficult.

Coastal wetlands and waterways around rainforests could be most affected by pollution because they may not have been burned for years.

Prof Finlayson says funding and long-term commitment will be needed from local and state governments.


NSW Rural Fire Service spokesman Greg Allan says rain, cooler temperatures and high humidity has helped firefighters control and extinguish blazes in northern parts of the state..

“We now have 46 fires burning and it’s (previously) been around 60 every day so that is a good thing,” Mr Allan told AAP on Thursday.

“It doesn’t look like as much rain is going to get down to the southeast where our main fire ground concerns are but we’re really hoping – fingers crossed.”