“We expect there could be hundreds of house owners and caravan owners in town to mop up,” said Lake Conjola Community Association president Robyn Kerves.

Resident Col Ashford says he has consulted a legal firm and started organising a public meeting place and drumming up numbers.

Lake Conjola streets and yards were submerged from Monday morning to early Wednesday as the lake level rose to a peak of 2.08 metres AHD after 290 millimetres of torrential rain.

Many residents believe if the lake entrance had been open, the extent of flooding would have been greatly reduced.

“I believe if the dredging council has committed to had been done on time in July and early August there would not have been any flooding,” Mr Ashford said.

However, Shoalhaven City Council’s natural resources and floodplain manager Isabelle Ghetti said “flood risk exists when it rains heavily, even if the lake is already open”.

“Council officers had taken photos of the high tide and the berm was below 1.2 metres,” Ms Ghetti said.

“We knew the lake would breach before the trigger point was reached and that was confirmed at 7.30am on Tuesday morning.

“We advised that the lake would continue to rise, by then there had been almost 250 millimetres of rain.

“Flood modelling shows in such conditions, even if the entrance had been open, it would not have changed the peak flood level.

Ms Ghetti said the lake peaked at 7.30pm Tuesday night just over two metres.