Recent heavy rainfall across the Sunshine Coast and Moreton Bay regions of Queensland have proven the effectiveness of Unitywater’s program to reduce sewage overflows on private property.
Executive Manager of Unitywater’s Infrastructure Services Division, Glen Babington, said overflows were often caused by large volumes of stormwater entering the network via incorrect household stormwater connections and cracks in the sewerage mains.
Mr Babington said Unitywater has delivered an extensive three-year program of works to tackle the problem, focusing on areas where overflows had previously occurred.
“While it’s difficult to compare extreme rainfall events because of the variance in duration and intensity, we have seen a significant reduction in sewage overflows in homes over the last three years,” he said.
“The most recent heavy rain event resulted in only two properties experiencing sewage surcharges, compared to 10 surcharges from the 27 January event last year, and 40 from the 24 January event in 2012.”
Mr Babington said home rainwater downpipes incorrectly connected to the sewerage network instead of the stormwater system had been a major contributor to the problem.
He said Unitywater had inspected more than 47,000 properties and 16,000 manholes over the last three years and found 2,244 properties with incorrect connections.
“We’ve had a very positive response from our customers and to date, around 1900 have rectified the problem,” Mr Babington said.
“We’ve also renewed 31.5 km of sewer mains to prevent stormwater infiltration into the network.
“That adds up to a lot of stormwater that no longer enters the sewerage network.”
Between July 2010 and December 2013 Unitywater invested $404 million in sewerage infrastructure projects across its service area to upgrade and maintain the network.