Biological Hazards

Biological hazards pose a threat to the health of living organisms: people, plants and animals. They include pandemics and biosecurity threats.

If biological hazards are not controlled, avoided or managed, they could significantly affect human health or affect New Zealand’s economy. Industry sectors (such as agriculture and fisheries) can be adversely affected, as well as human and animal health and infrastructure.

 

Biosecurity Threat (animal epidemic, plant and animal pests)

As Auckland has a large international airport and ports, it is at risk of animal and plant pests or diseases being bought into the country. Unwanted pests and diseases could severely impact New Zealand's horticulture, agriculture and forestry industries and delicate ecosystems. Auckland is not only at risk from biosecurity threats, but must also but must be vigilant to halt the spread of any threat that does make it past our strict biosecurity precautions at the ports and airport.

The actual consequences and response required to a biological threat affecting Auckland will depend on the nature of the organism.

Technological

Technological hazards include lifeline utility disruption, major transport accidents, hazardous substances, dam failure, cyber-threats, terrorism and civil unrest.

Auckland has been affected by technological threats in the past.

 

Hazardous Substance

Many kinds of hazardous substances are transported, stored and used in Auckland and many industrial areas are located near residential and environmentally sensitive areas.

A hazardous substance is anything that may be:

• Explosive
• Flammable
• Able to oxidise
• Corrosive
• Toxic

Hazardous substance spills or accidents can affect a large area through explosions, chemical reactions or toxic gas plumes. These could cause health impacts, harm animals, habitats or ecosystems and contaminate land and water resources.

Climate Change

The International Panel on Climate Change has provided climate projections for New Zealand for 2040 and 2090.

Their Auckland projections include:

• Increase in the mean air temperature
• Increase in sea level due to thermal expansion within oceans and loss of ice sheets and glaciers
• Fewer periods of cold temperatures and an increase in the number and intensity of periods of high temperatures; expect more days above 25ºC
• Decrease in annual mean rainfall
• Increased frequency and intensity of extreme rainfall events due to a warmer atmosphere
• Increased intensity and frequency of El Niño, with an associated increase in the annual mean westerly wind flow
• Possibly more intense ex-tropical cyclones bringing torrential rain, strong winds and storm surges.
  
  

Impacts could include:

• Health problems from extreme temperatures
• Damage to properties and critical infrastructure from more intense inland flooding and coastal inundation
• Coastal erosion from larger waves hitting the coastline
• Disruption to agriculture and horticulture from water supply issues and more severe drought
• Fire from increased droughts and windier conditions.

 

Coastal Erosion

The extensive urbanisation of Auckland, a region with 3100 km of coastline, has resulted in exposure to hazardous coastal erosion and accretion processes and both 'soft' and 'hard' shoreline and cliff erosion.

'Soft shorelines' refer to sandy beaches and dunes made up of unconsolidated or very weakly consolidated materials. Sandy beaches in the Auckland region experience periods of accretion (net sediment accumulation) and erosion (net sediment decrease). On beaches experiencing a sustained period of erosion, sediment loss results from waves, currents and wind removing sediment from the beach faster than it is replaced.

Erosion and instability also happens from natural and human factors such as cliff height and modification. Geology is the main contributing factor that affects the extent of coastal erosion in Auckland.

Land instability and coastal erosion impacts:

• Danger to life in the case of sudden landslides
• Loss of land, particularly in coastal cliff environments
• Destabilisation of neighbouring slopes and properties
• Environmental impacts of sedimentation in waterways
• Secondary hazards such as leaking gas or water from broken pipes
• Loss of beach amenity due to cliff collapse or sea wall construction.

 

Land Instability

Land shape (geomorphology) and composition (geology) are the main factors that contribute to land instability. In Auckland, landslides and soil erosion occur in soft, weak soils that have been weathered over many thousands of years. Land instability may move rapidly or slowly and gradually.

Common examples of land instability in Auckland include:

• Landsliding (mass movement downslope of material under the influence of gravity), including: rotational slides, translational slides, slumps, flows, falls
• Subsidence (can occur on flat land as well as sloping, usually the result of draining or overloading weak soils)
• Tunnel gully erosion (tunnels form below the slope surface and eventually collapse)
• Stream and river bank erosion
• Coastal erosion
• Topsoil erosion.

 

Drought

Auckland is vulnerable to drought, which can have severe implications for people, agriculture and the economy. Unlike most natural hazards, the onset of drought can be slow and go unrecognised. It usually occurs from a lack of precipitation, commonly rain, over a long period. There are two types drought:

• Agricultural drought is when soil moisture becomes so low, plants can no longer grow. As soil moisture decreases, plants become stressed and die if the drought is prolonged. An agricultural drought ends when adequate amounts of rain restore soil moisture levels 
• Hydrological drought refers to a significant reduction in the amount of water available in rivers, lakes and groundwater (the hydrological system). This happens when rainfall is well below expected levels in a large catchment area for an extended period, often leading to water supply shortages.
  
  

What do I need to do to be ready?

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