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Updated Tsunami Evacuation Zones: Directors’ Guideline for CDEM Groups

The updated Tsunami Evacuation Zones: Directors’ Guideline for CDEM Groups [DGL 08/16] has been published.

It has replaced the former guideline of the same name (DGL 08/08). 

DGL 08/16 Tsunami Evacuation Zones (pdf 3.9MB) and (.docx 7.3MB)

Background to the revision and review process

The former guideline Tsunami Evacuation Zones: Directors’ Guideline for CDEM Groups [DGL 08/08] was developed following establishment of the National Tsunami Working Group (TWG) in 2007. Ten regions across New Zealand have used this guidance to develop evacuation zones and maps, and considerable experience in using it has been gained. Additional drivers for updating the guidance include:

  • Considerable experience with tsunami alerts and events, both nationally and internationally, and further updates in scientific understanding of New Zealand’s tsunami hazard have occurred.
  • The 2011 Tohoku tsunami in Japan reinforced the importance of having well-founded tsunami risk management planning. It led to a review and subsequent report of tsunami risk to New Zealand. This work was commissioned by MCDEM and published by GNS Science in 2013.
  • In 2014, the Resilience Fund supported a CDEM workshop in Gisborne to identify issues and challenges with using tsunami science to inform evacuation and land use planning, and to develop solutions and recommendations for achieving national consistency in approaches.

GNS Science was commissioned to update the Tsunami Evacuation Zones: Directors’ Guideline for CDEM Groups [DGL 08/08] in 2015, with support and input from CDEM Groups and the National Tsunami Working Group (TWG).  A draft guideline was circulated to CDEM Groups and other interested parties for consultation during  October/November 2015.

Key updates and/or additions to the guidance

Key updates and/or additions to the guidance are as follows:

Providing context: Outlining the guideline’s role within the tsunami management arrangements and relationship to other guidance e.g. Mass Evacuation (DGL 07/08]).

On the hazard: Updating information on sources and dynamics of the tsunami hazard.

Evacuation zones: Clarifying the relationships between levels of modelling, and the defining and establishing of evacuation zoning. This is the crux of the guidance whereby improvements in modelling enable more certainty and specificity in planning for evacuation.

Land use planning: Making links to the Resource Management Act (RMA) and the New Zealand Coastal Policy Statement 2010. For example, avoiding facilities for vulnerable groups in high risk areas and having layouts for new developments that will support evacuation needs. 

Vertical evacuation: New advice that vertical evacuation options (evacuation to upper floors or roofs of mid-to-high rise buildings or purpose-built structures, i.e. towers, within the evacuation zone) are to be considered where the distance to high ground precludes effective evacuation based on tsunami threat models for that area.

Triggers for an evacuation: Clarifying either a natural warning (when response times are short), or an official warning (and in which case evacuation zones are prescribed based on the threat level, i.e. anticipated wave size).

Public education and priority messaging:  To tie-in with the above and to update existing information. 

Advice for ports, shipping and people in boats:  New information about the role of the Harbour Master in port areas and safe evacuation depths for shipping and leisure craft at sea.