Coastal development at risk
Coastal development in the Waikato region has seen many subdivisions placed too close to the shoreline. The diagram below shows the current minimum and maximum distances (in metres) for houses in coastal settlements on the eastern Coromandel Peninsula. You can click on the diagram to see a larger version of it
.•The minimum setback distance (see bottom left of diagram) is the distance from the beach to the closest beachfront house. For most settlements on the eastern Coromandel Peninsula this distance is less than 50 metres.
•The maximum setback distance (see middle left of diagram) is the greatest distance between the beach and the first house. This varies from less than 50 metres at Wharekaho, to about 300 metres at Otama Beach.
•The average setback distance at most settlements is usually closer to the minimum distance than to the maximum.
Over time with rising sea level, beaches are likely to respond by adjusting upwards and landwards.
At many settlements, these houses are currently so close to the beach that they are at risk from natural coastal erosion processes. In some places, this has resulted in actual or potential damage to structures and buildings from natural coastal processes. The Coastal Development at Risk indicator measures the number of houses and properties at risk from coastal erosion.
At many settlements, these houses are currently so close to the beach that they are at risk from natural coastal erosion processes. In some places, this has resulted in actual or potential damage to structures and buildings from natural coastal processes. The There are at least 26 settlements in the region where subdivision has extended into shifting coastal margins. Houses are at risk in many of these settlements including:
Although our region’s coastal areas don’t yet appear to be eroding in the long-term, in the future, sea level rise and other changes likely from predicted global warming will change this. Beaches on the eastern Coromandel Peninsula could erode more than 15-20 metres over the next century, as shown in the diagram below. This would greatly increase the number of properties and houses at risk.
When calculating coastal development setbacks, scientist and councils must understand short term fluctuations in the shoreline as well and long term trends for shoreline change.
It is therefore important to identify the hazards associated with coastal erosion and to reduce the future risk to coastal communities through planning, education and ongoing research and monitoring. In order to better manage future development along the coastline, Councils sometimes use Coastal Development Setbacks, to ensure houses are safely located away from erosion-prone areas.
Coastal development setbacks
One way to protect future development at coastal settlements is to ensure an adequate “setback” is applied between development and the sea to provide enough dune buffer to protect from the effects of wind, storms and flooding. The diagram below shows the risk areas that need to be identified before any coastal development goes ahead.
Coastal development setback controls exist at a number of settlements around the Waikato Region, and are usually implemented through the local District Plan. Most recently, the Waikato Regional Council and Thames Coromandel District Council have gathered and reviewed scientific evidence of shoreline change at Coromandel Peninsula beaches, and recommended development setbacks to guide the placement of development in the future. This information has been incorporated into the recent Thames Coromandel District Plan Review.
The Council is applying two coastal development setbacks:
•Current Coastal Erosion Line (CCEL): the area adjacent to the shore that is known to be subject to natural coastal erosion processes with current sea level.
•Future Coastal Protection Line (FCPL): the area that may be at risk from additional long term erosion associated with future sea level rise. Maps showing these setbacks are available here: