7. Coastal Hazards

Close-up of toetoe plants on sand dune.
 

Summary

RPS objective

To avoid or mitigate the adverse effects of natural hazards by minimising and where practicable, avoiding the risk to life and damage to property, infrastructural services and other aspects of the environment, from natural hazard events.

Pressures

· Existing coastal development with inadequate provisions for mitigation of natural hazards resulting in the modification of natural coastal systems and increased natural hazard pressures.

· Development intensification, subdivision and redevelopment within areas subject to coastal hazards.

· Modification to natural coastal systems, such as dunes and saltmarsh, reducing the natural hazard buffering capacity of these features.

· Climate change and the effects of sea-level rise and potential for increased intense tropical cyclone activity.

· Cyclicity in global climate systems, such as El Niño Southern Oscillation (ENSO), and the effects on natural coastal hazards such as erosion.

State

· Northland's west coast beaches mostly display a long-term state of shoreline stability and in some locations accretion. However, there are several embayed harbour beaches that are eroding due to low sediment supply and shoreline modification, notably Omapere Beach on the west coast.

· The long-term state of east coast beaches is more varied. While many display a trend of shoreline stability, there are a significant number of eroding beaches proportional, in part, to the extent of man-made shoreline modification.

· Over the past five years conditions for east coast beaches have favoured beach building, with beaches tending to accumulate sand and dunes repairing and prograding seaward.

· A number of Northland coastal communities are at potential risk from erosion, flooding and tsunami hazard largely due to historic development when knowledge of hazards and mitigation requirements were less well understood.

· Coastal hazard zones, usually for erosion and flooding hazards, have been derived for more than 24 coastal communities.

· More than 630 dwellings and 1090 properties are located within or partially within identified coastal hazard zones. The total capital value of these properties in 2006 was approximately $450 million.

Doing well

· At least nine coastal hazard assessments have been undertaken for Northland, many of which have delineated coastal hazard zones.

· Coastal hazard assessment is ongoing, with current focus on better understanding tsunami hazards for the region.

· Beach profile monitoring is undertaken regularly to better understand shoreline dynamics and an accurate lidar topographic dataset is currently being undertaken for most coastal communities.

· Coast care restoration and enhancement of dune systems, hazard zone delineation and rules and submissions on resource consent applications for activities in areas likely to be subject to coastal hazards are assisting in achieving coastal hazard management objectives.

Areas for improvement

· Preparedness for and understanding of tsunami hazards and the implications of climate change and sea level rise for Northland.

· Revise coastal hazard zones and methodologies used, particularly for further defining the coastal inundation hazard and the integration of information on inundation, flooding and erosion coastal hazards.

· Engagement of the community with coastal hazard preparedness and measures to increase awareness of natural processes and hazards.

· Promote a consistent and coordinated approach towards coastal hazard management throughout Northland.

· Integrate the management of the coastal marine area and land margins to make sure activities do not exacerbate coastal hazards.

Coastal hazards are natural physical processes with the potential to cause loss of life or property. Northland's coast is at risk from a number of coastal hazards, including: ·...
Coastal development The coastal development boom that has occurred since the 1950s has resulted in a number of coastal subdivisions with inadequate setback distances or having...
Natural shoreline dynamics Shoreline ‘state', that is the trend in the location of the shoreline, can generally be classified into three categories: · Eroding (shoreline is...
Policy documents The Regional Policy Statement for Northland (NRC 2002) provides an overview of resource management issues in Northland, including those with regard to coastal...
The following are key points towards implementing improved future management of coastal hazards in Northland: · Continue to monitor shoreline movements and undertake coastal hazard...
The following are some key ways you can be involved in reducing the risk of coastal hazards to yourself and others. Coastal hazard zones Contact the relevant District Council or...
During 17 to 19 September 2005 a moderately intense low-pressure weather system (pressure at Dargaville was recorded at 983 hPa, where mean pressure is 1014 hPa), with mean peak...
The Whangarei District Council has undertaken a restoration project to reinstate a dune system which had been compromised through the introduction of exotic plant species and...
CDEM Act. 2002. Civil Defence and Emergency Act 2002. More information on the Ministry of Civil Defence and Emergency Management's website at the following...
Published: 03 Apr 2008