Blue Mountains City Council is investigating the sudden loss of water from a dam at Springwood golf course used by firefighting aircraft.
The dam almost emptied overnight last month, prompting fears a structural problem was to blame for the rapid loss of water.
But a council spokeswoman said two inspections have suggested the structural integrity of the dam “was sound”.
The design engineer who constructed the dam carried out a second inspection on February 5, following a separate visual check on February 1.
“The design engineer is also of the view that the structural integrity of the dam is sound,” said the spokeswoman.
“Initial thoughts are that the loss of water maybe due to a change in hydrology of groundwater on the site. Groundwater levels fluctuate and are affected by many factors, including drought.”
Dye-testing on the dam is due to happen next week [starting Monday, February 11] to help pinpoint the exact cause of the problem.
“When a leak is suspected, all sources of water loss should be thoroughly checked. Council hopes to have a better understanding of the water loss once the dye testing is completed,” said the spokeswoman.
The state government announced $80,000 for the expansion of the golf course dam in 2015 following the 2013 bushfires. The new, 3.5 megalitre dam was ready for use by firefighting aircraft in 2016.