Wheat

Flooding creates water quality issues in rivers and creeks

Wednesday 26 October, 2022
Widespread flooding across the Goulburn Broken catchment continues to create significant impacts for communities and the environment. One of the effects on the catchment’s waterways is decreased water quality as a result of flooding which is expected to be an ongoing issue into summer, as temperatures increase.

Widespread flooding across the Goulburn Broken catchment continues to create significant impacts for communities and the environment.

One of the effects on the catchment’s waterways is decreased water quality as a result of flooding which is expected to be an ongoing issue into summer, as temperatures increase.

Simon Casanelia, the Goulburn Broken Catchment Management Authority’s Environmental Water and Wetlands Manager, said low dissolved oxygen levels, as a result of blackwater, was occurring in some waterways.

“Floodwaters have carried large quantities of organic material such as leaves, twigs and grass into our rivers and creeks which turns the water a dark brown or black colour. As the material is broken down it can reduce oxygen levels in the water which can kill fish and other aquatic fauna,” Mr Casanelia said.

“The scale of the flooding means it’s difficult to improve water quality.

“In some cases, water for the environment can be used to provide refuge for native fish or help dilute the poor quality water, however, this is only possible if good quality water is available and when flow in the rivers and creeks drop to normal operational levels.”

Mr Casanelia said river managers, scientists and environmental water holders were monitoring water quality in the catchment’s river and creeks.

Since the weekend, hundreds of fish deaths in the Broken Creek between Numurkah and Nathalia have occurred, with poor water quality from flooding the likely cause.

“The fish that have died include invasive European carp and native fish such as Golden perch and Murray cod,” Mr Casanelia said.

The EPA has been notified of the fish deaths.

Mr Casanelia said further fish deaths may occur throughout the catchment as floodwaters move through waterways.

“The floodwater may have an impact on water quality and aquatic fauna in the coming weeks and months, into summer.”

 Watch this 90-second YouTube clip for more information about the causes and effects of blackwater.

The community is encouraged to report fish deaths to the EPA on 1300 372 842.

 

Dead carp in the Broken Creek at Nathalia 25.10.22