Australia: Flood warnings as heavy rain forecast across burnt out regions in NSW
By Lisa Cox
[Grace Legge, a senior meteorologist at the Bureau of Meteorology] said while rainfall was welcome, fire grounds were also more vulnerable to severe weather that could increase runoff of ash and silt into waterways.
The extent of any water quality impacts on water in the dam will depend on the timing and intensity of the rainfall.
Two silt curtains designed to trap material that could pose a risk to water quality have been in place since January.
The department said on Wednesday the heavy falls would also increase the risk of organic debris ending up in waterways, which could reduce water quality and “may trigger fish deaths in already stressed river systems”.
Several fish kills have already occurred this year as the result of ash from bushfires, and other organic matter and sediment, washing into local catchments.