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Land Hazards

Image for the Land Hazards page.
 
This page contains information about coastal and urban land stability and reports about land hazards to assist those who are planning property development in the district.
Updated: 16/01/2014 8:24 a.m.

Land hazards are risks from natural hazards including land instability, flooding, coastal hazards and fire.

Land hazard maps  

Our Geographical Information System (GIS) mapping system displays comprehensive land hazard maps for the Whangarei district. 

Maps contained in the research reports on land instability and coastal hazards listed in the table at the bottom of this page are separate from the GIS.

Using the GIS maps

In the GIS, select the module named 'Hazards' and search for the address or select an area from the locations box. A map of that area or street will display which includes any hazards which may have been identified for that area. The maps can be magnified to see closer details. 

Click on the 'Layers' tab as well to filter the hazard types and make your search more specific. To view the hazard maps, follow the link below.

Land instability

Geological characteristics and soil types in the district mean that some areas are unsuitable for development. Inappropriate earthwork activities and / or the removal of vegetative cover also contribute to land instability. 

Coastal instability

Coastal hazards pose a significant threat to a high number of communities in the district. Between 2001 and 2005, a series of land instability assessment reports were commissioned for coastal areas that were under development pressure within the Whangarei district.

Urban instability

A further series of reports was commissioned in 2006 to assess slope instability for five large areas on the outskirts of Whangarei City.

Coal mining

Coal mining was formerly a major industry in Northland and major coalfields were located at Kamo and Hikurangi, both of which are now urbanised. Hazards such as subsidence, sink hole formation and unstable fill restrict development in these areas.

Engineering assessment reports of the subsidence hazard resulting from mining in Hikurangi and Kamo give us the basis for the preparation of an updated and revised policy on development within these two areas.

Coastal hazards

Erosion, landslips and sea water flooding are the dominant natural coastal hazards along the district's coastline.

Coastal erosion is either a long-term trend or a significant short-term shoreline fluctuation, especially on sand dune-backed coasts. Landslip is directly associated with coastal erosion where the geology is relatively weak and prone to slope failure.

Severe coastal storms or tsunami produce waves which can temporarily flood low-lying coastal areas. The effects of climate change are likely to increase hazards in the coastal zone.

Flooding

Tropical storms and high rainfall intensities  expose many areas to flooding. There are obvious floodway areas plus areas that are susceptible to ponding. 

A Flood Susceptibility Report was undertaken in response to submissions on the District Plan and the District Plan maps show all the flood susceptible areas as they were documented in 2001. 

Our GIS maps are used where specific property information is requested and in assessing building consents.

Our District Plan Policies and Rules can be viewed by following the links below.

District Plan - Policies - Natural Hazards [67kb]

District Plan - Resource Areas Rules - Natural Hazards [192kb]

Contaminants in soil

The National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health (the NES) ensures that land proposed for development is assessed for soil contamination.

Contaminants in Soil

Viewing the Land Stability reports 

To view the land instability, coastal hazard and flood susceptibilty reports, select from the list below by clicking on the '+' next to the document heading. Each individual document opens in a new window.

The appendices to the reports contain maps and plans which are too large to display online. If you would like a copy of any of them, please contact the Policy and Monitoring Department, phone +64 9 4304 200.

Resources

Disclaimer/Copyright

Whangarei District Council owns this website and the information, images and photographs in it are subject to copyright. No portion may be copied or republished without prior permission of Whangarei District Council. We have made every reasonable effort to provide accurate and reliable information. The use of any information is at the website visitor’s own risk and discretion.