As part of the North Shore City Council’s Project CARE, a programme to address community expectations of beach water quality, AWT was called on to identify which catchments required rehabilitation.

The investigation utilised CCTV cameras in all of the main sewers and lateral. Manholes and private drainage were also investigated. Data was then loaded into AWT’s SEWCOM model which accurately identified catchments to be rehabilitated.

Subsequently AWT supervised the contracts for rehabilitation including 6km of main sewer as well as associated manholes and laterals.

“We were able to rehabilitate some laterals using lining, a technique that AWT was instrumental in introducing to New Zealand.”

A 42% reduction in infiltration has been achieved in the in one mini-catchment with similar results to be expected when other mini-catchments are reviewed.