This page contains the coastal and urban land stability reports, mine and flood hazard reports for the Whangarei district to assist those who are planning property development.
Updated:
5/04/2012 1:53 p.m.
What are natural land hazards?
Risks from natural hazards include land instability, flooding, coastal hazards and fire.
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.
Viewing 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.
GIS Maps
Reports
A range of research reports on land instability and coastal hazards have been commissioned by Council. The reports, which are listed at the bottom of this page, contain maps which are too large to display on this website.
Please contact the Policy and Monitoring Department if you would like to view the maps associated with these reports. Phone: +64 9 4304 200.
Land instability
Land instability issues arise from inappropriate earthwork activities and/or the removal of vegetative cover.
The effects of these actions result in property damage, risk to human health and safety, and also affect water quality, natural functioning of water bodies and sediment control.
Coastal hazards pose a significant threat to a high number of communities in the district.
Coastal instability
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 for 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 with over five million tonnes extracted. Major coalfields were located at Kamo and Hikurangi, both of which are now urbanised. Potential development in these areas is constrained by hazards such as subsidence and sink hole formation. Areas of cut and fill also present a risk where the fill may be unstable and therefore unsuitable for use and development.
Council commissioned an engineering assessment report of the subsidence hazard resulting from mining in the Hikurangi and Kamo areas. The reports give us the basis for the preparation of an updated and revised policy on development within these two areas.
Coastal hazards
Coastal hazards pose a significant threat to a high number of communities in the District. Coastal erosion, landslip and flooding from the sea are the dominant natural coastal hazards along both sheltered and open-exposed coasts.
Coastal erosion exists as 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 coastal geology is relatively weak and prone to slope failure.
Flooding from the sea occurs from either severe coastal storms or tsunami that results in waves overtopping the coast and temporarily flooding low-lying coastal hinterland. The identified coastal hazards are forecast to be increased by the effects of climate change.
Policies and Rules can be found in Chapters 19 and 56 of the District Plan.
The maps and diagrams are appendices to the reports and are very large documents. If you would like a copy of any of them, please contact the Policy and Monitoring Department, phone +64 9 4304 200.
Flooding
The high rainfall intensities and the occurrence of tropical storms in the District expose many areas to flooding hazards. There are obvious floodway areas plus areas that are susceptible to ponding. Traditional residential development has centred around the alluvial plains and the coastal foreshore, where the probability of flooding or ponding is high.
The Flood Susceptibility Report was undertaken to inform the District Plan and to address submissions on the District Plan. The maps in the District Plan show all the flood susceptible areas as they were observed in 2001. Subsequent work is also shown on the GIS maps which are used where specific property information is requested and in assessing building consents.
Policies and Rules can be found in Chapters 19 and 56 of the District Plan.
Contaminants in Soil
The National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health (the NES) came into effect on 1 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 the 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.
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.