Natural hazards – what do you think?

 Jacobs River Church – Westland District

The West Coast has been subject to an increasing number of natural hazard events in the last few years, and this, along with changes to the Resource Management Act mean that an important part of the new plan will be managing the risk of natural hazards. 

Natural hazards to be addressed in the Plan 

There are a lot of different hazards which are present on the West Coast, this table outlines the key hazards and some ideas about how they could be managed in Te Tai o Poutini Plan. Alongside these planning measures, there will continue to be Civil Defence initiatives and other Council work programmes to manage hazards. 

Approaches to natural hazard management 

Granity – Buller District

When developing the approach for natural hazards we are intending to use the following strategies: 

b. Avoid the natural hazard

If there are known natural hazards in areas that are not developed, zoning to prevent future development in these areas. In other words don’t put people and assets in harm’s way. 

c. Accommodate the natural hazard

In some locations where the hazard can be managed with lower risk to people and property use measures that anticipate hazard risk – for example raising floor levels against flooding, provide alternative inundation pathways and require relocatable houses. 

d. Protect from the natural hazard

Westport – Buller District

Currently the most commonly used method for some types of natural hazard, this involves holding the line using natural buffers (e.g. sand dune restoration, wetland enhancement or creation, beach nourishment) or hard structures (e.g. seawalls, groynes). 

a. Retreat from the natural hazard

Moving existing people or assets away from the hazard in a managed way over time, or as a consequence of damage after a hazard event. For example by zoning areas that people can move to, and having rules preventing rebuilding if property is destroyed by a hazard.

Type of hazardExample locationsExample management methods
Coastal erosionGranity, Rapahoe, Bruce Bay, Karoro, O’Neils, Punakaiki, Hector/Ngakawau, Barrytown• Require buildings to be relocatable
• Identify areas for future managed retreat for existing development
• Put in place “no build” hazard line
• Identify areas where protection works are acceptable
• Identify sources of rock for quarrying for protection works
Coastal inundationCarters Beach, Westport, Blaketown• Require freeboard under dwellings, or dwellings to be lifted up
• Identify areas for future managed retreat for existing development
• Put in place “no build” hazard line
• Identify inundation pathways
River floodingMokihinui, Westport, Hokitika, Greymouth, Karamea, Franz Josef, Fox Glacier, Haast, Cobden, Paroa• Require freeboard under dwellings, or dwellings to be lifted up
• Identify floodways
• Put in place “no build” hazard line
• Identify areas for future managed retreat for existing development
Riverbank erosionParoa (Salt Water Creek)• Riparian setbacks for building
• Put in place “no build” hazard line
• Require buildings to be relocatable
• Identify areas for future managed retreat
• Identify areas where protection works are acceptable
• Identify sources of rock for quarrying for protection works
Earthquake (Alpine Fault)Springs Junction, Inchbonnie, Franz Josef• Put in place “no build” hazard line
• Identify areas for future managed retreat for existing development
• Require specific structural design
TsunamiOkarito, Karamea, Westport, Hokitika, Greymouth, Port Jackson• Put in place “no build” hazard line
Landslide / Rock Slope Failure / Debris FlowLittle Wanganui, Otira, Greymouth Hills, Cobden Hills, Runanga, Punakaiki, Hector, Miko Coastline• Put in place “no build” hazard line
• Identify areas for future managed retreat for existing development
Liquefaction as a result of an earthquakeInangahua Junction, Westport, Karamea• Require specific foundation design for dwellings in high risk locations

Questions