However the company said there was no need to be alarmed, as the ponds still had ample room.

Like most of the region, the Pilliga forest was battered by heavy rain throughout the week.

Ex-government ecologist David Paull was so worried about the ponds’ ability to handle the deluge of water, he jumped in a plane to get an aerial view of them.

He wasn’t happy with what he saw, taking dozens of photos. Mr Paull said there were “real question marks” over the ponds’ capacity to handle heavy rain and flooding.

The NSW Environment Protection Authority (EPA) said it was aware of heavy rain in the Narrabri area and sent staff to inspect the water levels. It found no evidence the water had overflown and no environmental concerns were identified.

“The EPA’s inspection confirmed that the ponds still have significant capacity,” an EPA spokeswoman said.

“The EPA will continue to monitor the site.”

A Santos spokeswoman said the two holding ponds, which are divided into four cells, weren’t in any danger of spilling over.

While it may look like one of the cells was close to flowing into its neighbour, the company says the room around the edge of the pond paints a different picture.

“Today the ponds are not even close to the maximum permissible operating level,” the spokeswoman said.

Heavy rain and flooding was considered during the construction of the ponds.

“The Leewood ponds have ample capacity to deal with Santos’ ongoing operational needs and any rainfall events - including one in one-hundred year events,” the spokeswoman said.

“The Leewood ponds meet or exceed all of the NSW Government’s Dam Safety Committee guidelines and are operated in accordance with the design standards.”