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 C-2 Systems Engineering Australia Pty Ltd July 2016 C.1 Introduction This Appendix presents examples of the numerical modelling capability to represent realistic tropical cyclone storm tide events that underpins the present study simulations and regional estimates of extreme water level statistics. The SEAtide storm tide prediction model, which is a deterministic version of the SEAsim model, is used here to reconstruct the likely coastal impacts of TC Lam. These are compared with the mostly qualitative post-event inspections (BoM 2015). C.2 Coastal Impacts Tropical Cyclone Lam crossed the West Arnhem coastline around 3 km SE of Milingimbi on 19/02/2015, in the vicinity of the Glyde River. It passed about 20 km seawards of Galiwinku earlier on the same day. Although there were no real-time tide gauges to capture the storm tide response, the post event report (BoM 2015) field survey notes as follows: Galiwinku Beach erosion around smaller islands on the approach to Galiwinku suggested a storm tide exceeding Highest Astronomical Tide (HAT). On the ground, debris lines were identified around 2 m above HAT level along the bay to the west of the community. Milingimbi An assessment of debris at the high tide mark suggested a storm surge of around 0.5-1 m above HAT. It is understood that the Bureau of Meteorology in Darwin utilised real-time storm tide estimates using V1 of the SEAtide model. C.3 SEAtide V3 Modelling The following illustrations are from the SEAtide V3 model using the updated parametric models developed for the present study. The storm best track parameters were extracted directly from the BoM online historical dataset. Figure C-1 shows the regional BoM best track plot of TC Lam in SEAtide. Figure C-2 shows the area near landfall and the close proximity to Milingimbi, noting that it was fortuitously located on the right-oftrack, while the peak storm tide is expected left-of-track in the vicinity of the Radius to Maximum Winds, which was estimated as about 20 km. Figure C-3 shows the estimated peak Storm Surge across this area, noting a peak of about 3.6 m just east of landfall, with Milingimbi having a 2.3 m surge. The coastal configuration appears to have concentrated the surge response towards the centre of this