Unitywater is urging residents to help keep stormwater out of the sewerage network in the wake of significant rainfall.
With rainfall totalling more than 400mm across services area in Noosa, Sunshine Coast and Moreton Bay, large volumes of stormwater entered the sewerage network and caused some sewage pump stations to overflow.
“The system is designed to overflow in abnormal weather conditions,” Unitywater Executive Manager Infrastructure Services Glen Babington said.
“In these circumstances, the discharge is diluted, posing the same sort of risk as all other floodwaters. Where customers reported displaced manhole covers, crews were deployed to reinstate the manhole cover and disinfect the surrounding area.”
During a rain event, waterways can be contaminated with debris and residential runoff from pets and septic systems, development runoff such as sediment, fertiliser, oil and through natural bird and bat populations.
“Unitywater has had crews working hard 24/7 to restore the network to normal operating levels and we thank all of our customers for their patience,” Mr Babington said.
Mr Babington said Unitywater had a rolling investigation program targeting priority areas where sewage overflows happen regularly. Crews use smoke testing and CCTV cameras to identify places where stormwater is entering the sewerage network.
Smoke testing has been carried out at about 30,000 properties and 2,000 of these have had illegal connections to the stormwater network. The majority of these have been rectified to help significantly reduce the number of sewage overflows.
“Given that stormwater entering the sewerage system can overload it, Unitywater has been carrying out testing over the last four years to identify where houses have illegal connections into the sewerage system,” he said.
With respect to concerns over sewage overflows affecting the health of Pumicestone Passage, Unitywater does not have a Sewage Treatment Plant that discharges directly into that waterway.
As part of its ongoing infrastructure planning, Unitywater has earmarked an estimated $26 million for an upgrade to the Caloundra Sewage Transport System.
There are several phases involved in this project, with construction expected to begin in July 2015. The system will be operational by December 2016.
The upgrade is in response to population growth in the area and will address sewage overflows in some areas during extreme weather events.