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.
29/04/2013 3:13 p.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 land hazard maps for the Whangarei district including coastal erosion, instability areas, mine zones, flood zones, effluent unsuitability and effluent disposal potential.
These maps are separate from maps contained in the research reports on land instability and coastal hazards.
Using the GIS maps
In the GIS, select the tab named 'Hazards' and enter the name of an area or street in the 'Locate' 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.
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 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.
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 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 pose a significant threat to a high number of communities in the district. 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.
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) came into effect in January 2012.
The NES provides a nationally consistent set of planning controls and soil contaminant values. This is to ensure that land affected by contaminants in soil is appropriately identified and assessed before it is developed.
If necessary, the land is remediated, or the contaminants contained, to make the land safe for human use. All territorial authorities (district and city councils) are required to give effect to, and enforce the requirements, of the NES. The NES does not affect existing land uses.
The NES controls changes to the use of land:
where the use might introduce a risk to the health of people using the land, or
where activities such as subdivision and earthworks are intended to be undertaken on sites where it is likely that past uses have contaminated the soil.
The NES requires an assessment of whether it is ‘more likely than not’ that the land that the proposed activity will take place on either, currently is, or has previously, been used for an activity that may potentially contaminate the soil.
A list of those activities that are considered to contaminate the soil is called the Hazardous Activities and Industries List (HAIL).
Follow the link below for further information about the NES.
Information on the National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health (the NES) (Ministry for the Environment website) Opens in a new window.
We assess all resource consent applications to determine whether the NES regulations apply to the piece of land and proposed activity.
For further information, follow the link below.
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.