Preventing Sewerage Overflows
INVESTIGATION AND REPAIR WORKS TO REDUCE THE OCCURRENCE OF SEWAGE OVERFLOWS IN THE MACKSVILLE SEWERAGE SYSTEM
The Macksville sewerage system is subject to overflowing during prolonged or high intensity rainfall events. The discharges have the potential to cause public health concerns and adversely impact the oyster industry on the Nambucca River.
Council is working with the EPA and other State Government Authority stake holders to take action to try and reduce the number of overflows.
Council monitoring of the sewerage system indicates that the primary cause of the overflows is stormwater ingress into the sewerage system. This can occur through illegal cross connection of property stormwater pipes to the sewer system or from surface flow making its way into incorrectly installed property overflow relief gullies or into broken/ damaged pipes and access chambers in Council infrastructure.
In order to determine the extent and location of the stormwater ingress problem Council is proposing to carry out the following works:
• Dye testing of private properties in problem catchments
• Inspection of access chambers in problem catchments
• CCTV camera inspections of sewer pipes in problem catchments
• Relining or patch repair of damaged sewer pipes as required.
Dye testing involves discharging water coloured with dye into gutters and downpipes and checking the downstream sewer to see whether any coloured water is present. The presence of colour indicates a cross connection that will need to be rectified. Properties with defective plumbing or cross connections will be forwarded a Notice by Council instructing the owner to undertake remedial plumbing works to prevent the stormwater entry.
CCTV is used to inspect Council’s underground sewer infrastructure and determine where defective joints or broken pipes are allowing stormwater ingress. The relining or patch repair of the pipes restores the integrity of the pipe system preventing the entry of stormwater.
Council has been undertaking the dye testing works in house and proposes to engage contractors to complete the CCTV camera inspections and reports as well as any pipe relining or patching works.
Dye testing - Dye testing works have been concentrated in two large catchments in the northern end of Macksville – one draining Kings Point to a pump station off Sturdee Street the other bounded roughly by Wallace Street, Boundary Street and Willis Street draining to the pump station at Willis Street Oval. The first stage of works has been completed with some properties to be retested once inspection shafts that could not be found are uncovered.
Council has issued the majority of Notices to those property owners with cross connection or defective plumbing.
CCTV inspections - The contractor commenced this work on the 27 February 2023 and it is expected to take 2 to 3 weeks to complete
Pipe repair - Pipe relining and patching work is planned to take place early in the new financial year with funding to be allocated in that budget.
What Can I Do
Property owners can assist Council in reducing the occurrence of sewage overflows by doing the following:
• Being aware of their property plumbing pipework and ensuring that overflow relief gullies (ORG) do not allow the entry of surface water and that downpipes are not connected to the sewer or do not discharge to the ORG.
• Ensuring that they do not flush so called “flushable wipes” into the sewerage system. These cloth wipes do not break down and are the cause of a significant number of blockages in pipes and pumps that increase the risk of overflows and significantly increase maintenance costs. The only things that should be flushed down the toilet are the 3 P’s – poo, pee and paper.
Refer to the brochures, ‘Don’t Flush Wipes’ and ‘Keeping Stormwater Out of the Sewerage Network, included on the website for more information.
Your actions can assist in maintaining good water quality in the Nambucca River and keeping the oyster industry viable