Coastal hazards

Our coastal environment is constantly changing as the shoreline moves and sea level varies. These changes become a hazard when they threaten human life and property.

Coastal erosion and coastal flooding are the main coastal hazards in our region. Most of this threat is to buildings located within the zone of natural shoreline change.  

Our coastline

The Waikato region’s coastline has about 1,150 km of open coast and shoreline, including estuaries. Our coastline is made up of the following distinctly different areas:

• East Coast - Coromandel Peninsula.
• West Coast - Coromandel Peninsula and the Firth of Thames.
• West Coast - from just north of Port Waikato heads to the Mokau River mouth.

The East Coast has mainly medium-sized estuaries and wide sandy beaches separated by rocky headlands and cliffs. Some open coast beaches are backed by extensive areas of sand dunes.

The West Coast of the Coromandel Peninsula and the Firth of Thames is a mixture of rocky coastal fringe and narrow sand and gravel beaches. The West Coast (from Port Waikato to Mokau) features long sandy beaches, areas of cliffs and dunes and three large estuaries.

Coastal hazards

Coastal hazards in the Waikato region include:

• coastal erosion
• wind erosion
• coastal flooding
• climate change (sea level rise)
• tsunami.

The main coastal hazards in the Waikato region are coastal erosion and coastal flooding.

Houses are at risk from coastal erosion or flooding in over half of our coastal settlements in the region. The risk from coastal erosion has been caused by building too close to the sea to allow for natural shoreline changes. In many cases coastal development has damaged vegetation and sand dunes that protect the shoreline. Climate change will worsen this situation due to rising sea level, changes in winds, waves and currents, and an increase in the strength and frequency of coastal storms.

Coastal flooding can also threaten ‘lifeline’ services such as water, power, telecommunication and transportation networks.

What Waikato Regional Council is doing

• We developed a coastal inundation tool to show what areas may be subject to inundation (flooding) from projected sea level rise. we need to better understand the extent of the effects of inundation.
• We developed risk mitigation plans, which minimise the effect of natural hazards on the Waikato economy and community.
• We investigate and monitor coastal hazards such as erosion and flooding.
• We develop site-specific coastal mitigation strategies, based on the Coastal Flooding Regional Management Strategy and the Coastal Erosion Regional Management Strategy.
• We have emergency management responsibilities in the Waikato region under theCivil Defence Emergency Management Act 2002. This involves planning, staff training and the provision of response teams ready to deal with emergencies and Civil Defence.
• Our Regional Coastal Plan sets out methods of improving coastal hazard management, and our Regional Policy Statement includes significant resource management issues relating to our coastal resources.
• We provide coastal flood protection and advice to territorial local authorities about risk from coastal erosion and flooding. We also develop region-wide strategies to manage coastal erosion and flooding. These strategies also identify issues that warrant further investigation.
• We work with Beachcare groups, made up from local communities and district councils, to protect and restore beaches.

Useful links

• Hazards and emergency management
• Coastal inundation tool
• Civil Defence and Emergency Management
• Waikato's coasts
• Regional Policy Statement
• Coastal publications
• Community-based Dune Management for the Mitigation of Coastal Hazards and Climate Change Effects: A Guide for Local Authorities(external link) (Bay of Plenty Regional Council)(external link)
• New Zealand Tide Predictions(external link) - Land Information New Zealand (LINZ)