The clean-up in South Australia's Southern Flinders Ranges and mid-north continues, after the Bangor bushfire and severe flooding more than a week ago.
The Port Germein Road will be closed for some time and black sludge has spread through farmland and creeks.
Mary Ann Young from Primary Industries and Regions South Australia says the downpour pushed black sludge across the agricultural land.
"My observations are that it's perhaps more the run-off that's come and it's laden with ash and debris from the fire," she said.
Meanwhile, the Department of Planning, Transport and Infrastructure continues to assess damage to the Port Germein Gorge Road.
The department's assistant regional manager Harold Carn says a dry stone wall was damaged beyond repair and needs to be rebuilt.
"We're looking at alternatives that give us a timely solution, a cost-effective solution and a resilient solution," he said.
He says rumours of a permanent closure to the road are false and repairs should be finished within six months.
© ABC 2014
08:35 EDT The weather bureau has warned more severe weather could hit the New South Wales mid north coast today after heavy rain caused flash floods on Monday.