Lyttelton Harbour wastewater project: work package number 2

Update

What

We are installing a new wastewater pipe from Lyttelton to Governors Bay as part of the Lyttelton Harbour/Whakaraupo wastewater project.

Where

Lyttelton Harbour between Naval Point and Governors Bay.

When

Work will start on 5 June for four months.

Why

To transfer untreated wastewater from Governors Bay wastewater treatment plant to Naval Point, when the consent for pumping treated wastewater into Lyttelon Harbour runs out in December 2018.

Contact

The contractor is McConnell Dowell Constructors Ltd phone 0508 623 266 between 8am and 5pm, Monday to Friday.

This work is part of the wider Lyttelton Harbour wastewater project, which will see untreated wastewater from Lyttelton, Governors Bay and Diamond Harbour pumped to the Christchurch Wastewater Treatment Plant.

The Lyttelton wastewater project is required due to the approaching expiry of existing resource consents, permitting the discharge of treated wastewater into the Lyttelton Harbour. Currently wastewater in Lyttelton, Diamond Harbour and Governors Bay is treated at wastewater treatment plants in those locations, before being discharged into the harbour. The existing resource consents for the Governors Bay, Diamond Harbour and Lyttelton wastewater treatment plants require that routine treated wastewater discharges into the harbour cease by December 2018, 2021 and 2029 respectively.

Lyttelton to Governors Bay pipeline

From early June we will begin working on installing a marine pipeline between Naval Point in Lyttelton and the existing wastewater treatment plant near the end of Jetty Road in Governors Bay.

The new wastewater pipes are being welded into eight 625m strings along the foreshore at Naval Point in Lyttelton. These strings will be connected as they enter the water via a launch way to be built on the Naval Point breakwater, near the grassed area adjacent to the public boat ramp at Naval Point. The pipe will be pulled into place using a winch. The anchor point for the winch will be installed near Jetty Road, Governors Bay. Construction of these will commence in early June 2018. The area near each of these locations will be fenced and clearly signposted. 

In preparation for burying the pipe one meter below the seabed, a trench will be dug using a backhoe dredger. The pipe will be weighed down with concrete ballast blocks that are secured around the pipe every 5.75 meters, each weighing 180kg. The winch, along with a team of divers, will pull and guide the pipeline into place. The trench will be backfilled to secure the pipe.

Exclusion zone for all harbour users

The barge from which the dive crew and backhoe dredger will operate, has a number of anchor points extending from it under the water. An exclusion zone of 200 meters will be in place around it at all times as it moves along the planned corridor for the pipe, this is highlighted on the map that follows.

Please check with the Harbour Master for any new notices to mariners about this work prior to accessing the water near the location of work.