Flood blackwater causes fish deaths and odours in NSW

A collaborative effort is underway between NSW AELERT member agencies to monitor the extent and severity of fish deaths and odour in the Hunter Valley. The incident is a result of suspected 'blackwater', following a period of significant rainfall and flooding in the area.

The inundation occurred when water levels in local creeks and rivers peaked simultaneously, causing water to flow over low lying surrounding land and pick up decaying vegetation, dirt and other organic matter.

NSW EPA North Branch Director, Gary Davey, said that the natural flooding process depletes oxygen levels in waterways, resulting in a distinctive black colour. The stagnant water can cause fish deaths and a rotten egg smell.

"The hot weather we are currently experiencing is likely to exacerbate these odours," Mr Davey said.  

NSW EPA is working closely with the Department of Primary Industries (DPI), Office of Environment and Heritage, Port Stephens Council and DPI Water to monitor the extent and severity of the impact.

Flood water DoE

Diagram courtesy of the Department of Environment.

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