When the treated water pipeline from the Waingake Water Treatment Plant was damaged by Cyclone Gabrielle, Gisborne’s drinking water was compromised.
The Gisborne District Council had multiple challenges within the water supply infrastructure, but the immediate focus was on repairs to get limited treated water to where it was needed.
The existing 525mm OD concrete lined steel pipeline was attached to the TWLPB4 bridge that suffered substantial damage to both the bridge and abutment which also supported a 11kVa powerline. There were a further 7 bridges that failed along with 9 major breaks in the pipeline. Access to the pipeline was challenging.
The Solution
Fulton Hogan installed 500mm SDR17 HDPE to the affected areas but needed to tie in to the existing 525 concrete lined steel pipe.
Hygrade Water, supplied through Hynds Water, were able to provide two DN 500 Novia Siria Multigrip couplers and liners to complete the urgent repair. The couplers have a wide tolerance that allowed two different pipe materials with different dimensions to be connected. The Multigrips are a restraint fitting which ensures the HDPE pipe is securely anchored to the fitting.
