Tasmania flood repairs cost utility millions

Posted 1 September 2016

Tasmania floodTasWater is facing an estimated $25 million dollar repair bill after June floods left considerable damage to water and sewerage infrastructure across the state.

The corporation expects it will take up to 12 months for infrastructure to fully recover, with Pet Dam and the Forth water treatment plant hardest hit.

“Pet Dam had displaced concrete panels in the chute floor and walls,” said TasWater Asset and Product Management General Manager Andrew Moir.

“Syphons were installed to mitigate the loss of the raw water supply with dam levels being managed to allow continued supply of raw water to Burnie whilst spillway repairs are completed.”

Dam repairs are due to be completed by the end of September 2016, but work at Forth will take longer.

“Forth WTP suffered inundation of the diversion valves and the 20ML treated water supply (TWS) reservoir,” Moir said.

“The diversion valves were cleaned out and restored when the over land waters subsided and the Forth WTP brought back onto line supplying treated water.

“However, the restoration of the TWS will be a significant project with current restoration works estimated to be completed in February 2017.”

It will take up to a year to finalise all the electrical, pump station and civil repairs – including embankments and lagoons – across a number of sewerage treatment plants.

But without TasWater's planning and rapid response the damage could have been worse, Moir said.

“Where possible, infrastructure was de-energised and sites made safe before evacuation by shutting down and removal of chlorine tanks from sewerage treatment plants deemed likely to be inundated,” he said.

“From a water supply perspective, other than the three precautionary boiled water alerts, we were able to maintain water supply throughout the flood period.

“From a sewerage system perspective, there were three shellfish areas affected by overflows but preparations put in place by the industry ahead of the storm event minimised the impact.”

Moir said the flooding had provided an opportunity to improve business resilience by reviewing water-level modelling.

“This will provide a clearer view of what assets will be impacted at varying flood levels and what  upgrades can be considered as part of a risk assessment process to further reduce the impact of future floods,” he said.