Understanding and Mitigating Hazards

2015_04_jimmys_beach_erosion_1.jpg

Jimmys Beach NSW erosion April 2015 (Credit NSW OEH)
Jimmys Beach NSW erosion April 2015 (Credit NSW OEH)
Key Topics:

Project Status:

This project, which is now in its utilisation phase, developed better predictions and forecasts for extreme water levels arising from storm surges, surface waves, continental shelf waves, meteorological tsunamis, mean sea level rise and the transition from tropical to extra-tropical cyclones.

The occurrence of extreme water levels can lead to loss of life and damage to coastal infrastructure. Potential impacts and hazards of extreme water level events along our coasts are significantly increasing as populations grow and mean sea levels rise. To better prepare, coastal engineers, emergency managers and planners require accurate estimates of extreme water levels.

It is vitally important that the exceedance probabilities of extreme water levels are accurately evaluated to inform risk-based flood management, engineering and future land-use planning. This ensures the risk of catastrophic structural failures due to under-design or expense due to over-design are minimised.

This project, which is now in its utilisation phase, developed better predictions and forecasts for extreme water levels arising from storm surges, surface waves, continental shelf waves, meteorological tsunamis, mean sea level rise and the transition from tropical to extra-tropical cyclones.

Storm surges caused by tropical cyclones are well known to pose a risk. Recent technological advances allowed the team to develop a high-resolution numerical model capable of analysing ocean dynamics to better understand how storms will impact local beaches on an Australiawide scale. The advanced, high resolution 3D hydrodynamic model coupled with a wave model included the effects of waves breaking on top of storm surges caused by wind and pressure. An experiment based upon Tropical Cyclone Yasi indicated that wave setup contributed up to 35 per cent of total surge height and was 6-10 per cent of wave heights at 10 m depth. This supports the commonly applied engineering approach of applying a 10 per cent factor for waves in estimates of water levels. Another important factor included the orientation of the coastline to waves and wind. The experiments showed large variations in setup and surge over the scale of tens to hundreds of kilometres that was mostly related to the relative intensity and direction at which Cyclone Yasi impacted the coast. The results suggest that coupling a wave and surge improves the accuracy of storm surge predictions and provides a useful tool to determine areas of the Australian coastline are more susceptible to flooding and erosion from extreme waves.

However, a lesser-known effect of landfalling cyclones is the generation of coastally trapped waves that can propagate along the coast and influence water levels thousands of kilometres away. Examples of such waves include continental shelf waves that travel to the left along the coastline in the southern hemisphere and are common along the Australian coastline. Numerical modelling by the team has demonstrated how particular cyclone properties influence the generation of continental shelf waves and through this improves the ability to predict the influence of continental shelf waves on extreme water levels along the coast.

Meteotsunamis are generated by meteorological events, particularly moving pressure disturbances due to squalls, thunderstorms, frontal passages and atmospheric gravity waves. Relatively small initial sea-level perturbations, of the order of a few centimetres, can increase significantly to create destructive events through the superposition of different factors. In August 2014, a meteotsunami propagating along the mouth of the Swan River in Fremantle resulted in a ship breaking its moorings and impacting on a rail bridge. The team has made significant impact in understanding the mechanisms underlying the development of meteotsunamis and their potential threat.

As tropical cyclones move toward the poles they can interact with the surrounding environment causing the tropical cyclone to lose tropical characteristics and become more extra-tropical in nature – this is known as extra-tropical transition. Storms that undergo extra-tropical transition pose a serious threat by extending tropical cyclone–like conditions over a larger area and to latitudes that do not typically experience such storms. Findings show that in Australia the south west of Western Australia is the area most at risk from extra-tropical transitions of cyclones, late in the cyclone season, when intense cyclones are most likely to interact with approaching cold fronts.

The data generated by the project will be made available via web interfaces with the possibility to develop the data into a spatial interface. Access to this information will support state and local government planning departments, the Bureau of Meteorology’s severe weather warnings and forecasts, and state and federal government emergency management planning, coordination and response activities.

Post fire field work
17 November, 2017
New journal articles and reports on CRC research are available online.
16 August, 2016
New journal articles and reports on CRC research are available online.
17 May, 2016
A series of videos, now available, highlight some of the benefits of CRC research and the problems that the science is trying to solve.
Current predictions, predicted waypoints (red markers) and the course Chari’s team swam (white squares).
15 April, 2016
I recently took the plunge for the annual Port to Pub open ocean swim in WA, and I think I can now claim the unique distinction that I have first-hand experience of both a seismic tsunami and a meteotsunami. My group at UWA was predicting the currents for the race, and we predicted the occurrence of the meteotsunami.
15 March, 2016
New journal articles and reports on CRC research are available.
Undertaking storm surge research at a NSW beach. Photo: Geoscience Australia
12 November, 2015
An update on research progress from projects in the Coastal Management cluster.
The Winter 2015 edition of Fire Australia magazine.
28 July, 2015
The Winter 2015 edition of Fire Australia magazine is now available.
Locals brave the elements during April’s east coast low at Jimmy’s Beach, NSW. Photo by NSW SES.
24 July, 2015
Researchers are investigating where extreme water levels could impact Australia’s coast and what can be done to mitigate the risk.
3RRR
17 June, 2014
Einstein A Go-Go, a weekly science radio show, has featured new Bushfire and Natural Hazards CRC research over the last two weeks.
Year Type Citation
2017 Report Pattiaratchi, C. Developing better predictions for extreme water levels: annual project report 2016-17. (Bushfire and Natural Hazards CRC, 2017).
2016 Conference Paper Rumsewicz, M. Research proceedings from the 2016 Bushfire and Natural Hazards CRC and AFAC conference. Bushfire and Natural Hazards CRC & AFAC annual conference 2016 (Bushfire and Natural Hazards CRC, 2016).
2016 Conference Paper Hetzel, Y., Janekovic, I. & Pattiaratchi, C. Improved predictions of Australian extreme sea levels through a coupled wave-surge model. AFAC16 (Bushfire and Natural Hazards CRC, 2016).
2016 Report Pattiaratchi, C., Wijeratne, E. M. S., Hetzel, Y. & Janekovic, I. Predicting continental shelf waves in Australia. (Bushfire and Natural Hazards CRC, 2016).
2016 Report Pattiaratchi, C. Developing better predictions for extreme water levels:Annual project report 2015-2016. (Bushfire and Natural Hazards CRC, 2016).
2015 Conference Paper Rumsewicz, M. Research proceedings from the 2015 Bushfire and Natural Hazards CRC & AFAC conference. Bushfire and Natural Hazards CRC & AFAC annual conference 2015 (Bushfire and Natural Hazards CRC, 2015).
2015 Conference Paper Janekovic, I., Hetzel, Y. & Pattiaratchi, C. Improved modeling of extreme storm surges and waves along the Australian coast - non peer reviewed extended abstract. Adelaide Conference 2015 (2015).
2015 Journal Article Pattiaratchi, C. & Wijeratne, E. M. S. Are meteotsunamis an underrated hazard?. Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences 373, (2015).
2015 Presentation Pattiaratchi, C., Janekovic, I. & Hetzel, Y. Developing better predictions for extreme water levels. (2015).
2015 Report Hetzel, Y. & Pattiaratchi, C. Review of Tropical-Extratropical Cyclone Transitions Annual Report 2014. (2015).
2015 Report Pattiaratchi, C. Developing better predictions for extreme water levels: Annual project report 2014-2015. (Bushfire and Natural Hazards CRC, 2015).
2014 Journal Article Haigh, I. D. et al. Estimating present day extreme water level exceedance probabilities around the coastline of Australia: tides, extra-tropical storm surges and mean sea level. Climate Dynamics 42, 121-138 (2014).
2014 Journal Article Haigh, I. D. et al. Timescales for detecting a significant acceleration in sea level rise. Nature Communications 5, (2014).
2014 Journal Article Pattiaratchi, C. & Wijeratne, E. M. S. Observations of meteorological tsunamis along the south-west Australian coast. Natural Hazards 74, 281-303 (2014).
2014 Journal Article Haigh, I. D. et al. Estimating present day extreme water level exceedance probabilities around the coastline of Australia: tropical cyclone-induced storm surges. Climate Dynamics 42, 139-157 (2014).
Developing better predictions and forecasts for extreme water levels around Australia
25 Aug 2014

The occurrence of extreme water levels can lead to loss of life and damage to coastal infrastructure. 

Key Topics:
Meteorological Tsunamis along the Australian Coastline
18 Aug 2015

Meteotsunamis incur damage on coasts all over the world. As they are more likely to occur than geophysical tsunamis, it has resulted in many coastal probelms in Australia in the lack of presence of efficient public awareness systems. Identifying where and when meteotsunamis pose a threat will aid coastal management and planning.

Key Topics:
Developing Better Predictions and Forecasts for Extreme Water Levels Around Australia
18 Aug 2015

The occurrence of extreme water levels can lead to loss of life and damage to coastal infrastructure. To better prepare, coastal engineers, emergency managers and planners require accurate estimates of extreme water levels.

Key Topics:
Yasha Hetzel Conference Poster 2016
12 Aug 2016

This project is developing better predictions and forecasts for extreme water levels arising from storm surges, surface waves, continental shelf waves, meteorological tsunamis, mean sea level rise and the transition from tropical to extra-tropical cyclones.

Key Topics:
Improving predictions of extreme sea levels around Australia
29 Jun 2017

This project provides a comprehensive benchmark that will underpin the ability to manage the impacts of extreme water levels on coastal regions at local, regional and national scales.

Key Topics:

Research clusters

Explore by keyword