Greater Wellington Regional Council Climate Change Mapping Information Help Background Comments

Sea Level Rise and Storm Surge Modelling


This website shows a dynamic map of areas in the Greater Wellington region that will be affected by sea level rise.

Sea level is known to be rising in the Wellington Region as elsewhere in the world. Currently sea level is rising at about 3mm per year in the region.

However sea levels rise is expected to accelerate in the near future due to climate change. Predictions vary but more information is listed here.

Use the slider bar at the side to match your chosen water level.
Explore the susceptibility of inundation by moving the slider up and down.

All levels are relative to Mean High Water Springs 10 (MHWS10)
MHWS10 is the mean high water spring tide exceeded 10 percent of the time.
It is often used as a practical high tide level for infrastructure design works, and also for estimating extreme high storm tides.
Learn more about tide levels.

Areas of inundation due to sea level rise were modelled in 2018 based off a detailed digital elevation model (DEM) of the Wellington Region.

Tide level offsets are based on values in a report produced by NIWA for the Parliamentary Commissioner for the Environment in 2016.

Elevation data was based off LIDAR survey data produced for the WAGGIS consortium in 2013.Learn more. Data accuracy for the Wellington CBD area is discussed in a note here.

SLR spectrum image Extreme value
2100
Max likely value
2100
Min likely value
2100

Sea Level Rise Modelling

Sea Level Rise predictions

Global average sea level has risen by about 16–21 cm since 1900,with almost half this rise occurring since 1993 as oceans have warmed and land-based ice has melted.
Relative to the year 2000, sea level is very likely to rise 0.3 to 1.3 m by the end of the century.
Emerging science regarding Antarctic ice sheet stability suggests that, for higher scenarios, a rise exceeding 2.4 m by 2100 is physically possible, although the probability of such an extreme outcome cannot currently be assessed.
(U.S. Global Change Research Program Fourth National Climate Assessment, 2018)

Historical sea level reconstruction and projections up to 2100 published in January 2017
by the U.S. Global Change Research Program for the Fourth National Climate Assessment.

How to use this page

Change map content

  • Click on the map window and drag to change the map view.
  • Use zoom tools or shift-click and drag to change the map extent
  • Use the slider bar to change the modelled inundation level (sea level rise), or click a radio button to change the sea level model used for storm surge.
  • Click on an inundation area (coloured map overlay) to view water depth details

Other tools

  • Click on the map to view the calculated values at any location
  • Click on the search tool and enter a name to find any placename in the region
  • Click on the layer control tool and choose an option to change the basemap type or overlays

Background to this page

Background

This webpage displays a dynamic map which shows the calculated inundation areas at a range of sea level rise values in the Wellington Region. Alternative map overlays show modelled storm surge flooding at different sea level rise values, for a 1% AEP (100 year) event. Inundation areas were modelled in 2017 based off a detailed digital elevation model (DEM) of the Wellington Region. Tide level offsets are based on values in a report produced by NIWA for the Parliamentary Commissioner for the Environment in 2016.

Elevation values

The basis for this mapping is a detailed digital elevation model (DEM) of the Wellington Region. This was based off a laser airborne (LIDAR) survey commissioned by the WAGGIS consortium in 2013. The survey data was subsequently reprocessed in 2017 by Landcare Research with funding from LINZ. The DEM was then recalculated to match the MHWS10 datum based off tidal values provided in a NIWA report. Colour overlays on the map show elevations at 20cm intervals above MHWS10.

Report and Data

This website follows on from a report produced by NIWA for the Parliamentary Commissioner for the Environment (PCE) in 2016. Data produced as an outcome of that report can be downloaded from the GWRC Open Data Site.

Please note

Please note these results are based on modelled data, and as such they are indicative only of likely changes, depending on future greenhouse gases emissions.

Scenario choice

It’s impossible to know which sea level rise estimate will be closer to reality by the end of the century, and therefore it is recommended that people’s planning incorporates a range of outcomes.