Council gives green light for Lake Ainsworth re-opening
DESPITE low levels of blue-green algae still being present, Lake Ainsworth has been opened to the public.
The lake was closed for swimming and other recreational use from February 13, with two successive cyanobacteria blooms keeping a red alert active until Thursday.
"There's still a little bit of algae but we're satisfied levels are below protocols," Ballina Shire Council's Graham Plumb said.
The section manager of public and environmental health said temperature, the still water and excessive nutrients, such as phosphorus and nitrogen, had contributed to the growth.
Dry conditions over the summer also may have helped growth, but the situation is a catch 22, as low rainfall tends to concentrate nutrients while decent rain sweeps nutrients into the lake.
Mr Plumb said predicting outbreaks was a difficult task, with many factors coming into play.
"We've done studies over the years and many little things have been done, they all help," he said.
"I also think installation of the aeration system has, anecdotally, improved the condition of the lake.
"You can do all these things but the nutrients still collect at the bottom of the lake and have to slowly soak through the sand dunes to the ocean."
Despite difficulties, Mr Plumb said the lakes environmental condition was slowly improving, possibly lessening the chance of algae blooms over time.