James Matthews, Paul Langedijk (GHD)
In February of 2021, a sink hole found on Jervois Quay brought Wellington’s CBD to a standstill. A partial closure of Jervois Quay created widespread congestion across Wellington’s road network, immediately garnering national media attention.
Urgent investigations discovered the sink hole was caused by a void formed above an aging stormwater pipeline. What was also apparent were several other damaged sections which could potentially cause additional voids. Immediately, the emergency response pivoted from a simple patch repair to a complete renewal of a stormwater main located beneath Wellington City’s busiest road.
After efforts to line the pipe were unsuccessful, an open-cut solution was viewed as the only option which would deliver a robust and long-term solution. The project team’s focus now shifted to considering how an upgrade could be completed while minimising disruption to the people of Wellington. This paper documents how 40m of stormwater pipe, spanning across a six-lane road servicing 14,000 cars daily, was completed in only four days.
The project was successfully delivered through the combined effort and collaboration of all affected parties. Coordination of the road network, water infrastructure, consenting requirements, public notification and design were completed and the works were constructed in a fraction of the time a project of this size would normally take.
An innovative approach was required to streamline project delivery. Extensive environmental control measures and monitoring near Wellington’s Harbour, large scale dewatering around high-risk structures and military-like coordination of multiple contractor teams all contributed to the success. Wellington Water’s collaborative whānau delivery model and the advantages of their longstanding relationships with consultants and contractors significantly contributed to the rapid emergency response, whilst maintaining a holistic view of the long-term service goals of the catchment.
This paper will detail how the emergency response and its learnings can be used as a blueprint for future emergency works, especially for critical assets located in highly sensitive locations. As water networks continue to age, more and more cases like Jervois Quay are likely to arise.