Coastal Flooding Simulator to include Hauraki Plains

Since 2016, Waikato Regional Councils’s excellent coastal flooding simulator has shown present and potential future flooding due to sea level rise around the Coromandel Peninsula.  Next month the coastline of the Hauraki Plains between Kaiaua and Kopu will be added to the simulator allowing more accurate assessment of coastal flood risk.  Many people will be shocked at the potential extent of coastal flooding due to sea level rise

Recently, Waikato Regional Council briefed the Hauraki District Council, and here are some of the slides from that presentation –


The simulator shows Present Day water level estimates  including tide and storm effects but NOT wave effects –


Sea Level Rise scenarios can be added to present-day water levels




Tide levels are different around the region so it is important to use the pre-defined water levels for the area you are looking at.  For the Hauraki Plains the “Firth of Thames” levels should be used.


The simulator shows both direct inundation (blue areas) and areas with no direct flow path to the sea — eg. via groundwater (green areas)



In a new feature flood maps will assume that over-topping and flooding will only occur when stopbank design crest levels are reached.  But remember do stopbanks fail eg. Egdecombe