Big water projects get underway

Diggers, trucks and a large drilling rig in St Mary’s Park, plus the closure of one end of Hackett St are the visible signs of the start of the first of two major water projects in St Mary’s Bay.

The first is a large drainage tunnel through the foot of St Mary’s Bay and the construction in Hackett St of a replacement inspection chamber for the intersection of wastewater and stormwater pipes, plus the relining of an old and failing pipe.

The second, not yet started, is the separation of combined wastewater and stormwater pipes. Herne Bay’s combined pipes will also be separated. As a result, in almost all weathers sewage overflows will reduce dramatically, with only stormwater being discharged into the harbour. This will lead to much cleaner water at Herne Bay and St Mary’s Bay/Westhaven beaches.

This could all have looked quite different if the St Mary’s Bay Association (and others) had not sought expert advice and devised alternatives to some parts of the 2018 resource consent granted to Auckland Council.

The key changes to the original design are:

  • The level of the tunnel is being lowered. Importantly, this will minimise instability concerns for properties above, and will allow above ground structures in reserve areas to be reduced or removed. The pump station at Pt Erin will be landscaped to surrounding ground level and there will no longer be any above-ground structures in the grassed area at St Mary’s Park;
  • Odour control poles planned for London Street have been removed and odour control/air vent poles in St Mary’s Park and Pt Erin Park will be relocated to minimise visual effects;
  • The pump station in Pt Erin Park is to be altered to prevent build-up of water in the tunnel (which will no longer be used for medium/long-term storage);
  • An old stormwater pipe running down from Hackett Street, under properties in lower St Mary’s Road, is to be re-lined to avoid risk of leakage and erosion under those properties; and
  • The head of the outfall pipe into the harbour is being modified to improve dispersal of stormwater and any overflows of wastewater.

In addition to these design changes, various conditions provide improved checks on compliance with the conditions. As part of this, a monitoring group (the St Mary’s Bay Project Liaison Group or SMB-PLG), comprising representatives of all key stakeholders, has been established. This will allow community oversight of the project throughout the construction period. It is too early to say whether we will need to re-engage our expert on any of the design matters, or any other experts for that matter, but we will keep the fighting fund in place until it is clear that we no longer have a need for it.