An Increasingly resilient transport network
A resilient network is one that is designed, developed and maintained to recover quickly from unplanned events. The regions road network is vulnerable to disruption or closure given an extreme event and this is because Wellington’s topography and relatively narrow corridors of development, infrastructure and transport across the region makes it relatively susceptible to disruption from natural hazards events and traffic crashes.
The first resilience measure refers to a regional risk register; the regional risk register was completed at the end of 2016. The register consists of a list of projects and set of maps that describe locations in the regional transport network that are vulnerable to an extreme event. The risk register will be updated as work is completed on these projects.
Planning and investment are needed in preparation of an extreme event to improve the resilience of existing key transport corridors and infrastructure and identify alternative access points. Another measure that addresses the importance of access in an event is the estimated time to reopen key supply lines and road connections to and within the region. The estimated times for access to key Wellington areas are shown the table below.
|Wellington CBD||Sea||4-5 days|
|Western Wellington||Barge (via Porirua)||5-7 days|
|Road connection to Porirua and Tawa||3 weeks|
|Road connection to the Wellington CBD area||3 weeks|
|Lower Hutt||Barge||5-7 days|
|Road connection to the Wellington CBD area||8-10 weeks|
|Upper Hutt||Road connection to Lower Hutt||3 days to 2 weeks|
|Kapiti||Road connection to the Upper North Island||1-4 days|
The estimated access times above were developed using the scenario of a major earthquake following the analysis of transport access into and around Wellington region (metropolitan areas). Major areas in our transport network which are vulnerable to disruption have been identified and long term strategies implemented to reduce this vulnerability.
The table shows the estimated time to set up the alternative access routes so that water, food and material supplies can flow into the region. Barges will initially bring these supplies in and it is estimated this will take up to a week in most areas to obtain access. The region will be isolated by normal road access for at least 120 days. This is due to likely landslips on state highway routes. Access within the region will also be fragmented due to landslips. An update on these access times is expected in the 2016/17 Annual Monitoring report.