Project CARE best practice sewer programme

An independent review this month concluded that Project CARE, North Shore City Council's 20-year programme of work to improve beach water quality, is more advanced than work being done by any other New Zealand councils and the vast majority of Australian wastewater management authorities.

The scope of the report produced by international professional services company GHD Limited, focused on planning undertaken to determine the major network improvements.

Project CARE is on track to meet North Shore City's wastewater network performance target of an average of two overflow events a year by 2021.

Works and environment committee chairperson, Joel Cayford, says the results of the review of city's sewer repair programme are good news for the community, which is funding improvements to the wastewater network.

"While Project CARE began officially in 2001 following wide public consultation, urgent work such as the Devonport sewer repair programme and Birkley Tunnel project began as early as 1998.

"The most cost effective work was scheduled to be done first, followed by work to avoid deterioration of the existing wastewater network," Councillor Cayford says.

"We've focused on reducing stormwater getting into the pipes and on storage facilities that contain wastewater and reduce pollution.

"Through careful planning and advanced computer modelling, Devonport and Narrow Neck were identified early as leaky wastewater catchments and a high priority for repair of the public and private sewers.

"Work started in 1998 and repairs to all the public sewers and more than half of the private sewers in these areas are almost finished. Rigorous investigations of the areas we've completed show a resounding 51 per cent reduction in stormwater infiltration.

"This has resulted in significantly fewer sewer overflows in Devonport, Takapuna and Milford this wet winter. This has shown us that targeting our effort in the most leaky catchments is spending our money wisely," Joel Cayford says.

North Shore City Council's general manager of water services, Geoff Mason, says with the repair programme in progress, the emphasis has been on major wastewater storage projects.

"So far we've built the Beach Haven storage tank and recommissioned and upgraded facilities at North Head in Devonport, Northboro in Takapuna, and Maunganui and Sulphur Beach in Northcote.

"We're six months into our 18-month construction period at Silverfield storage tank in Wairau and plan to start building the Browns Bay large sewer storage in early 2004," he says.

With works on the major network storage planned or under way, Mr Mason says the focus will move onto upgrading local sewers.

"We've advised residents in Narrow Neck, Hauraki-Belmont, Northcote and Browns Bay that we're upgrading the public and private sewer networks in their areas over the next nine months," Geoff Mason says.

"We expect Takapuna, Milford and Chatswood to be a priority for improvements after that," he says.

Mr Mason says that retesting the performance of the repaired sewers is being undertaken to confirm the priority projects for the current (2003/2004) financial year and further ahead.

North Shore City Council has plans to invest a total of $80 million to improve the performance of the local sewer network between 2001 and 2006.

The Project CARE work programme will be reviewed again around 2006 and at five-yearly intervals after that.

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