Interestingly, we used the Kaikōura coast transport corridor in the South Island and the Wellington city network as pilot studies. We applied this to several transport networks and this enabled asset owners and emergency response planners to understand the issues and incorporate into their resilience response planning.
In 2008, on my return from a New Zealand Society for Earthquake Engineering reconnaissance mission to learn from the devastating magnitude 8 Wenchuan Earthquake in China, I was thrust into the transport “war room” during the simulated Project Phoenix earthquake exercise. It shocked me that some of the state highway corridors were planned to be opened in a mere six days, when I had just observed similar highways being cut off for over six months in China.
By 2012 we had begun characterising the resilience of the highways in the Wellington region, integrating this with the local authority transport networks into one regional network resilience map. Insights from this work allowed us to promote the importance of resilience for the proposed Transmission Gully expressway and, building on the lessons from the 2008 Wenchuan earthquake, develop concepts to enhance resilience.
This led to an assessment of the critical resilience issues for Wellington’s transport network that incorporated GIS and assessed risks against degree of vulnerability in earthquakes, tsunami and storms, the first thing of its kind in New Zealand.
Key insights from the Canterbury earthquakes were incorporated as well as the impact of the Kaikōura earthquake on Wellington. Following Kaikōura roads were closed not just from damage, but also due to damage or collapse risk from adjacent buildings. With this in mind we extended the assessment to include resilience impacts on access associated with building damage.
Lessons from a variety of storm and modest earthquake events as well as the more devastating earthquakes reinforced the need to consider different level of hazards.
For example, a modest event – Low Impact, High Probability, where society is almost fully functional - requires a level of access approaching normal levels. However, a major event – High Impact, Low Probability – would see the socio-economy grind to a halt and priority access required for emergency response, supply of essentials and recovery from the event. These have quite different resilience needs and both need to be planned for.
Lessons from my reconnaissance following the 2016 Kumamoto earthquake in Japan, where major highway routes were closed for many weeks and alternative routes were required or access, reinforced the need to consider resilience as a region-wide system. We developed a business case for Waka Kotahi NZ Transport Agency that considered the Wellington transport network and led to us recommending strengthening alternative routes rather than just the primary route.
It’s challenging to juggle the consideration of multiple dimensions of availability and outage, differing needs in LIHP and HILP events, functionality and response and recovery across a spatially distributed and interconnected network. However, using GIS and this multi-dimensional approach we were able to develop a unique and robust programme of long-term resilience enhancement actions for Wellington. These include emergency response planning, enhanced preventative resilience enhancement measures, communication, strengthening of critical sections, introduction of new connections and measures that need to be integrated into future transportation projects.
I have no doubt that we’ll need to continue to adapt our thinking as we continue on the path to greater resilience.
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