Simulation of Tsunami and Flash Floods

2007

On December 26th 2004, a catastrophic Tsunami devastated many countries of South East Asia. The inland saltwater surge impacted upon the coastal soil and groundwater quality in low lying areas. The groundwater resources along the coastal aquifers were ...

Congress on Modelling and Simulation, 2005

Modelling the effects on the built environment of natural hazards such as riverine flooding, storm surges and tsunami is critical for understanding their economic and social impact on our urban communities. Geoscience Australia and the Australian National University are developing a hydrodynamic inundation modelling tool called AnuGA to help simulate the impact of these hazards.

2006

Geoscience Australia aims to define the economic and social threat posed to urban communities by natural hazards such as tsunamis. Predictions of the likely impacts of tsunamis can be made through the integration of earthquake and tsunami hazard research, community exposure and socioeconomic vulnerabilities. By modelling the likely impacts on urban communities as accurately as possible and building these estimates into land use planning and emergency management, we can better prepare communities to respond to tsunamis when they occur. One critical component in understanding tsunami risk is being examined by the Risk Assessment Methods Project (RAMP) at Geoscience Australia which has been developing a hydrodynamic inundation modelling tool developed specifically to estimate the consequences of possible tsunami impacts on Australian communities.

2005

Modelling the effects on the built environment of natural hazards such as riverine flooding, storm surges and tsunami is critical for understanding their economic and social impact on our urban communities. Geoscience Australia and the Australian National University are developing a hydrodynamic inundation modelling tool called AnuGA to help simulate the impact of these hazards.

2004

Piantadosi, J., Anderssen, R.S. and Boland J. (eds) MODSIM2013, 20th International Congress on Modelling and Simulation, 2013

Storm surge presents the greatest hazard to life in tropical cyclone (TC) events, and the Queensland coastline has particular vulnerability to such extreme events. Presently, the Australian Bureau of Meteorology (BOM) issues warnings of forecast storm surge magnitudes using a static look-up table of scenarios associated with forecast cyclone track parameters. In association with Emergency Management Queensland (EMQ), Griffith University has initiated a research project investigating the potential to dynamically model storm surge inundation in real-time during TC events. The project aims to optimise emergency planning and evacuation strategies for storm surge impacts for impending TC landfall by providing outputs at greater spatial resolution, extension into inundation modelling over land, and development of a probabilistic approach to storm tide simulation that may provide emergency managers with a more complete view of possible outcomes. Here we present an overview of a feasible systems approach to real-time storm surge forecasting optimised for run-time, including generation of an ensemble of forcing wind and pressure fields, a hydrodynamic model and post-processing of model output for delivery to emergency management agencies. An ensemble approach to TC forecasting suitable for storm surge modelling has been developed in order to gain an understanding of the critical effects of the spatial, temporal and intensity uncertainties in TC forecasts on the resultant storm surge forecast. Parametric wind/pressure fields for each ensemble member are generated to force the finite volume hydrodynamic model, which has been built using MIKE21 by DHI software implemented on Griffith University and project partner Queensland Cyber Infrastructure Foundations (QCIF)'s high performance computing facilities. Two versions of the hydrodynamic model have been constructed, calibrated and validated for TC storm surge: the 'nearshore' model with spatial resolution of ~1-2 km in the nearshore zone outputting discrete storm surge magnitudes, and the 'inundation model' with high spatial resolution capable of dynamically modelling storm tide propagation over land. The output of the nearshore model would be combined with a bathtub mapping approach to yield probabilistic storm tide inundation estimates. The inundation modelling yields storm tide depth surfaces directly, to be combined into a probabilistic surface. A case study comparing the simulation time required to model storm tide inundation using the two approaches for TC Yasi is presented. The nearshore modelling combined with the bathtub mapping approach yields achieveable run-times for an ensemble forecast. The inundation modelling approach is currently too computationally expensive for the ensemble forecasting method developed for this study and efforts to optimise the simulation time are underway. A comparison of the resultant storm tide inundation levels obtained by each approach is in progress. Understanding these differences may lead to the development of techniques to improve the bathtub mapping approach.

Continental Shelf Research, 2014

The east coast of New Zealand is known for being exposed to a variety of tsunami sources, both those arising from the nearby Hikurangi subduction zone and its associated crustal faults, and those arising from more distant parts of the Pacific. Using numerical simulations with a parallelized computer model, we assess the tsunami inundation hazard posed to the most populated coastal communities on the east coast of the East Cape region, New Zealand, which had not been evaluated before. Our tsunami inundation hazard study is based on severe but realistic scenario events from a selection of local and distant earthquake tsunami sources. Such modelling covers a gap in knowledge caused by the short historical record of tsunamis in this region (covering\200 years), and the sparse observations of historical tsunamis due to a largely rural population. We identify that the worst flooding is often not associated with the first wave arrivals, and that coastal oscillations can last a long time in distant events. The modelling results allow us to determine typical characteristics of the pattern of flooding, specific to an area. This information is important for emergency planning and preparedness.

… on Coastal …, 2009

In-depth studies of inundation dynamics extracted from tsunami simulations could contribute widely where detailed information about velocity fields and flow depth is needed for evacuation simulation in coastal urban areas. Therefore we have taken the city of Padang, West Sumatra, Indonesia, into closer consideration for detailed analysis of tsunami inundation risks. In this context, the paper presents a 2D numerical study that is used to evaluate relevant factors influencing the quality and reliability of the simulation results. We found basic factors such as the accuracy and resolution of the underlying digital elevation model as well as the influence of macro-roughness elements like buildings and other infrastructure significantly affecting flow fields and water depths on microscopic level. The results clearly show that attention must be drawn to the fact that it is highly important to collect and analyze highly-resolved spatial data in shallow water and near shore (on land) in order to deduce credible tsunami inundation scenarios as a basis for adequate coping and evacuation strategies for imperiled coastal regions.

Meteorology and Atmospheric Physics, 2002

A coastal ocean model capable of modelling tides, storm surge and the overland¯ow of¯oodwaters has been further developed to include the¯ux of water from tributaries and the forcing from wave breaking that leads to wave setup in the nearshore zone. The model is set up over the Gold Coast Broadwater on the east coast of Australia. This complex region features a coastal lagoon into which ®ve tributaries ow and is subject to¯ooding from extreme oceanic conditions such as storm surge and wave setup as well as terrestrial runoff. Weather conditions responsible for storm surge, waves and¯ooding include cyclones of both tropical and mid-latitude origin.