Wellington Water Supply Resilience Study

The Wellington region sits on the interface of the Australian and Pacific tectonic plates—it has a high risk of earthquakes and is threatened by a movement of the Wellington Fault. The fault has a one in ten chance of moving in the next 100 years, which would cause a magnitude 7.5 or greater earthquake.

Wellington Water engaged us to complete a resilience study. They wanted to identify critical areas within the network and determine a skeleton network with water supply distribution points that could provide a basic level of supply during an emergency event. 

We developed innovative sets of algorithms which analyzed the road or walkway network and found the shortest steepness-adjusted route between each property and all distribution points. Another algorithm was then created to determine the best route to connect reservoirs with critical users and distribution points. We identified approximately 400 kilometres of critical networks, with approximately 240 kilometres requiring seismic resilience upgrades, and developed a three-stage critical network upgrade program with capital expenditure spread evenly across each stage.

Our study successfully addressed community outcomes of how and where to provide access to a water supply within a reasonable timeframe after a major earthquake, and then identified a proposed program of investment for critical network upgrades.