4 objections have been lodged with the Environment Court against Auckland Council’s plan to dig a giant drain under houses along the St Mary’s Bay ridge, aimed at improving stormwater & sewage flows into the Waitemata Harbour.
Above: An aerial image showing where the 1km drain would be constructed.
The council’s Healthy Waters general manager, Craig McIlroy, told the strategic procurement committee yesterday 2 community organisations & 2 individuals had lodged objections, and the council had asked the court to set up a mediation process.
In his report to the committee, Mr McIlroy said the aim was to have the drain working by the end of 2020, meeting a timeframe for a number of large infrastructure projects to be in place before the America’s Cup yachting event, meeting of APEC (Asia-Pacific Economic Co-operation, to meet in Auckland, Wellington & Christchurch) and biennial Te Matatini festival, all in 2021.
The project involves the construction of a new trunk sewer to capture current overflows and divert them to a new pump station at Point Erin. When the capacity of the pump station is exceeded, overflows will go to a new sea outfall from Point Erin to deeper moving water in the harbour.
The key ingredient of the $30 million-plus project is a 1km conveyance & storage pipeline (1.8m internal diameter, about 2500mᶟ capacity) extending from New St to Pt Erin Park, underground & beneath residential properties, recreation areas & road reserve, with an invert depth ranging between 5m and up to 22m deep. (Check the 14 November story link below for further details of the project proposal).
The St Marys Bay & Point Erin improvement project went to a hearing by independent commissioners in November. They approved it on 9 November, but objectors were then heard by the council’s regulatory committee a week later. The committee deliberated in private, didn’t issue a decision in a minute but said the decision would be made public within a week.
Although that didn’t appear to have happened, committee chair Cllr Linda Cooper told me the committee had confirmed the commissioners’ decision. The project was back before the strategic procurement committee yesterday – starting in public then going to the confidential section of the agenda for discussion of financial implications, risks & mitigations arising from procurement of the project and next steps for procurement.
Mr McIlroy outlined the present situation in his report to the procurement committee: “At present, a combined sewer network carrying both stormwater & wastewater services about 15,000 households in central Auckland, including St Marys Bay. The network is very close to capacity and combined sewer overflows are frequent, with increasing public concern regarding these and pressure to reduce them.
“The St Marys Bay area experiences high frequencies of wastewater overflows from mainly 3 engineered overflow points. A further 2 discharge onto Masefield Beach.
“The St Marys Bay & Masefield Beach water quality improvement project has been designed to resolve these issues. It is the first major project to be funded through the council’s new water quality targeted rate and forms part of the broader western isthmus water quality improvement programme.”
Mr McIlroy said that, through undertaking this project, “further improvements to the combined network can take place without continued contamination of these beaches. This is important as the full suite of proposed solutions will take some time to implement.”
He said the regulatory committee had noted in its deliberations that “they do not think there is a causal link between the works & ‘cliff instability due to the depth at which the pipeline will be installed, the construction methodology, monitoring & the technology used.’”
14 November 2018: Tank to solve western isthmus overflows approved, round 2 begins Friday
Attribution: Council committee meeting, agenda, hearing documents.