Desperately needed rain is expected to continue lashing parts of drought-stricken NSW across Sunday and Monday. However, there are fears that the downpour may be a "double edged sword" in some areas.
The state's northeast and Northern Rivers regions are tipped to receive further showers on Sunday, as a system that has caused bucketing rain and flash flooding in Queensland moves south.
While downpours over the last several days have provided relief for a state ravaged by bushfires – with the number of blazes in NSW dropping from 111 to 73 in six days – experts are concerned.
The Bureau of Meteorology warns that heavy rain could lead to flash flooding and landslips in parts of southeast NSW and the south coast, as the weather system moves towards Victoria over the next 24 hours.
Bureau of Meteorology forecaster Abrar Shabren said on Saturday afternoon the effects of the downpour would be felt for at least another day in the northeast and Northern Rivers areas.
"The rainfall will continue for the next 24 hours and substantial rain is expected at those locations," he said.
The NSW SES says this could increase the risk of flash flooding, falling trees and landslips where fire has wiped out trees and growth.
The Tweed and Northern Rivers regions have so far copped the state's biggest falls, with Clothiers Creek receiving 250mm in the 24 hours to 9am on Saturday.
On the mid north coast, Grafton had 155mm of rain and Killabakh had 112mm.
While the rain is welcome in fire-affected parts of the state, there are also concerns about the erosion that comes with it.
Despite hopes that rainfall will fill dwindling catchments, some councils fear mass erosion will affect water supplies.
"The soil is kept together by tree roots and other biomass – if enough of that has been burnt away, the catchment will be prone to erosion and even mudslides," says University of NSW water expert Stuart Khan told the Northern Daily Leader.
"If it rains heavily and too much soil and mud washes into the reservoir, the sediment can overwhelm the treatment process."
Tamworth Regional Council has reportedly reached out to the NSW Soil Conservation Service for advice – especially in terms of treating water affected by ash – and other councils have done the same.
