Discussion on 2D Overland Modelling Approaches

With advances in technology, 2D modelling has been increasingly used to determine flood risks in Auckland and to predict overland flow paths in urban areas with greater confidence than the previous 1D modelling approaches.

There are a range of challenges in developing a 2D model that need to be considered. One of these challenges is how to represent the buildings, kerbs and other features. It often depends on the complexity of the study, the software and hardware capabilities.

During the previous 1D Flood Hazard Mapping studies undertaken for Auckland City buildings, kerbs and other obstructions weren’t needed to be represented in fine detail in order to represent the flood risks encountered. In more detailed 1D/2D studies AECOM used a fine 2D mesh and with this, the need to represent roads, buildings and other obstruction in finer detail was required. This paper outlines the various methodologies that can be applied to modelling buildings, kerbs and fences within a 2D model using project examples.

This paper will look at the lessons learned whilst developing the models. It will also outline the advantages and disadvantages of the different methodologies.