Territory Stories

NT Remote Communities Storm Tide Study and Inundation Mapping

Details:

Title

NT Remote Communities Storm Tide Study and Inundation Mapping

Creator

Systems Engineering Australia Pty Ltd

Issued by

Northern Territory. Department of Land Resource Management

Collection

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

Date

2016-07-01

Description

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

Notes

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.

Language

English

Subject

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

Publisher name

Northern Territory Government

Place of publication

Palmerston

Series

J1507-PR001B

Format

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

File type

application/pdf

Use

Attribution International 4.0 (CC BY 4.0)

Copyright owner

Northern Territory Government

License

https://creativecommons.org/licenses/by/4.0/

Parent handle

https://hdl.handle.net/10070/267238

Citation address

https://hdl.handle.net/10070/443309

Page content

NT Department of Land Resource Management NT Remote Communities Storm Tide Study and Inundation Mapping J1507-PR001B 5 Systems Engineering Australia Pty Ltd July 2016 remote possibility is far outweighed by its more likely combination with a mid-tide or mean water level. Secondly, some community sites lie within complex mangrovedominated estuaries that can act to mitigate the penetration of the storm tide (especially ocean waves) and limit the available local wave fetch such that there is reduced exposure to incoming wave energy that might generate breaking wave setup. Large areas of low lying or swampy ground can also dissipate the incoming volume of the surge wave. Thirdly, deepwater locations (>100 m), narrow continental shelves and isolated offshore islands can have a degree of immunity from extreme storm tide as such areas are generally not conducive to generating large storm surge responses. 1.4.2 Amplifying Effects on Extreme Storm Tide On the other hand, wide continental shelves, shallow coastal waters (with depths less than 25 m) and large wide embayments are ideal for concentrating and amplifying incoming storm surge events. When combined with an estuary having a narrowing upstream planform, this can increase storm surge magnitudes to very dangerous levels. Other factors that can amplify storm surge relate to the relative size (scale) of the TC relative to the coastal features, the angle of approach and the speed of approach. These can act to concentrate the storm energy into specific areas and result in significant storm surge amplification. Also, although a low tide protects against inundation, it also amplifies the storm surge magnitude that can be generated. Clearly all these complexities can only be reliably assessed using simulation techniques that will incorporate the wide range of possible variations in TC intensity, size, speed and angle for each section of a coastline, together with the tide variability. 1.4.3 Other Effects on Coastal Water Levels It should be noted that the present Study considers only the effects of tropical cyclones on coastal water levels and that other extreme weather events (e.g. seasonal monsoon) can create small storm surge events that influence water levels on broader and more frequent timescales. In many locations this can mean that a water level similar to or greater than the HAT level is commonly achieved in association with periods of high spring tides (aka king tides). In the Return Period context, TC-only water levels are then less likely than the other minor weather effects at short Return Periods. This often means that water levels will therefore be dominated by non-TC events below the 100 y Return Period (e.g. Haigh et al. 2012).