Title: Computational Modelling of Hydrological Impacts - Open source software developed by the Australian Federal Government.
Speaker: Ole Nielsen, Geoscience Australia Ole.Nielsen@ga.gov.au
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 have developed a hydrodynamic inundation modelling tool called ANUGA to help simulate the impact of these hazards.
The core of ANUGA is a Python implementation of a finite-volume method for solving the conservative form of the Shallow Water Wave equation. This method allows the study area to be represented by an unstructured mesh with variable resolution to suit the particular problem. The conserved quantities are water level (stage) and horizontal momentum. An important capability of ANUGA is that it can robustly model the process of wetting and drying as water enters and leaves an area. This means that it is suitable for simulating water flow onto a beach or dry land and around structures such as buildings.
To set up a particular scenario the user generates a mesh with regions and boundary segments identified by symbolic tags used to bind values to arbitrary functions supplied during the simulation. In addition, all quantities may be assigned or updated by supplying either constant values, arbitrary functions or general expressions combining existing quantities. Arbitrary forcing terms such such as wind stress or atmospheric pressure gradients may also be supplied. While this interface provides great flexibility due to Python's object model, dynamic typing and constructs such as generators, the computationally intensive components are written for efficiency in the C language working directly with the Numerical Python structures.
ANUGA has recently been released as Open Source. This strategy will enable free access to the software and allow the risk research community to use, validate and contribute to the software in the future.
The talk outlines the model implementation, provides validation results, identifies remaining challenges and describes ANUGA's role within the Australian Tsunami Warning System.