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NT Remote Communities Storm Tide Study and Inundation Mapping



NT Remote Communities Storm Tide Study and Inundation Mapping


Systems Engineering Australia Pty Ltd

Issued by

Northern Territory. Department of Land Resource Management


E-Publications; E-Books; PublicationNT; J1507-PR001B




Made available via the Publications (Legal Deposit) Act 2004 (NT).; 'This report documents tropical cyclone (TC) storm tide hazard analyses that will provide the basis for reliable risk analyses of major remote towns and indigenous communities on the West Coast, Arnhem Land and Tiwi Islands.' - Introduction


This Storm Surge Study Report was produced with funding provided by the Northern Territory and Australian Governments through the Natural Disaster Resilience Program. 'Numerical Modelling and Risk Assessment' - on cover.; Made available via the Publications (Legal Deposit) Act 2004 (NT).

Table of contents

Executive summary -- Introduction -- The study localities -- Methodology to assess the storm tide hazard -- Simulation model results -- Conclusion -- References -- List of Appendices A-C.




Storm surges; Storm surges; Cyclones; Maps; Mathematical models

Publisher name

Northern Territory Government

Place of publication





vi, 62, 4,3,8 pages : colour illustrations, colour maps ; 30 cm.

File type



Attribution International 4.0 (CC BY 4.0)

Copyright owner

Northern Territory Government



Parent handle


Citation address


Page content

NT Department of Land Resource Management NT Remote Communities Storm Tide Study and Inundation Mapping J1507-PR001B 41 Systems Engineering Australia Pty Ltd July 2016 4. Simulation Model Results The open coast storm tide estimates for the future Year 2100 projected climate change and sea level rise condition presented in this section are derived from the statistical simulation model. This uses the parametric wind, storm surge and wave models to generate 50,000 years of artificial storm events, each combined with the astronomical tide. This synthetic water level time series is then statistically analysed to determine the Return Period (or ARI; refer Appendix B) of the total storm tide levels throughout the region applicable to the Year 2100 projection. Results from the statistical simulation model are presented here in several different formats: Absolute levels relative to AHD13, which is the officially mapped datum; Levels relative to the local estimated HAT by the Year 2100, which provides a maritime reference point; Inundation depths relative to the nominal dune crest elevation representative of each site, which is an indication of potential flood hazard to the community. Each of these is then provided as: Tabulated Return Period values; Summary Return Period graphs; Site-specific Return Period graphs of each simulated water level component. These Total Storm Tide Level estimates are directly applicable to the open coast or beachfront locations and include the effects of the astronomical tide, storm surge and breaking wave setup14. Finally, the open coast water levels are then mapped onto the available land elevations at each site and examples of this are provided here for illustration15 of the impact. This mapping has been undertaken on the assumption that the areas of interest are relatively small in area and often located immediately adjacent to the coastline, such that the estimated open coast water levels can be reliably projected horizontally inland. This is sometimes referred to as bathtub mapping. 13 In each of the study sites it is assumed that AHD is equivalent to present Mean Sea Level (MSL) and that the AHD datum remains fixed irrespective of the sea level rise assumption. The indicated HAT levels include the client-specified sea level rise allowance of 0.8 m by the year 2100. 14 It should be noted that breaking wave setup is not considered to contribute to the coastal water level once the local dune crest level is exceeded and wave energy is allowed to dissipate over land. 15 As noted in Appendix A, electronically-mapped surfaces are a separate deliverable to DLRM to facilitate preparation of NT Govt map products.