A major cultural and environmental milestone has been achieved in Whakaraupō Lyttelton Harbour.
Construction on the $60 million Lyttelton Harbour Wastewater Project is almost complete with final commissioning now underway.
The Cashin Quay pump station which takes the wastewater from Lyttelton will continue to be monitored to ensure everything is operating as it should and the final steps will be to decommission the Lyttelton Wastewater Treatment Plant which is expected to be completed by the end of April.
A formal ceremony will be held to mark the end of the project.
Previously wastewater from Lyttelton, Governors Bay and Diamond Harbour was treated at wastewater treatment plants in each township before being discharged into the harbour.
The untreated wastewater from Governors Bay and Diamond Harbour was diverted to Simeon Quay, for pumping to the Christchurch Wastewater Treatment Plant last week and on Monday 23 January, the Cashin Quay pump station was switched on to take wastewater from Lyttelton to Simeon Quay, finally stopping the discharge of treated wastewater to the harbour.
“We are so pleased we’re in the final steps of finishing this major piece of infrastructure for the Whakaraupō Lyttelton community and mana whenua. We know it’s been in the pipeline for a very long time,” Head of Three Waters Helen Beaumont says.
Te Hapū o Ngāti Wheke spokesperson Yvette Couch-Lewis says Whakaraupō is an important place for traditional mahinga kai (food gathering), but due to the wastewater discharge, what was once an abundance of kaimoana had greatly declined in recent decades.
“Our hapū has never tolerated any wastewater discharge into Whakaraupō, but with new infrastructure in place, we can look forward to seeing the ecological health of the harbour improve over time and for kaimoana to thrive once again.
“Generations of the Lyttelton community have enjoyed using the harbour for recreation and to gather kai. We all want the same outcomes – a healthy harbour and the ability to sustainably use the moana to feed our whānau," she says.
Work has included construction of 7km of submarine pipelines to carry wastewater from Diamond Harbour and Governors Bay to Simeon Quay in Lyttelton.
From there, a 4.5km pipeline through the road tunnel and along the Heathcote Valley conveys the wastewater to Christchurch’s Wastewater Treatment Plant in Bromley.
The three old wastewater treatment plants have also been converted into pump stations with storage capacity, back-up generators and primary treatment facilities in case of emergency overflows. A new pump station built on Simeon Quay in Lyttelton and new pressure mains have been installed to connect the scheme together.
Increased storage capacity and improved pumping infrastructure will reduce the risk of wastewater overflows into the harbour during wet weather events.
“It’s a very complex project that has been delivered in stages working with the community and manawhenua within Whakaraupō,” Ms Beaumont says.
The work is part of the Whaka-Ora Health Harbour Plan to restore the cultural and ecological health of Lyttelton Harbour.