Analysis of pre/post flood bathymetric change using a GIS: a case study from the Gippsland Lakes, Victoria, Australia

In late June 1998, a damaging flood event occurred at Lakes Entrance (Victoria, Australia), which was partly due to retardation of floodwater flow through the Gippsland Lakes artificial entrance by the level of flood-tide delta sediment accretion in the Entrance and Reeves Channels. Analyses of digitised three-dimensional hydrographic datasets allowed the extent of pre and post-flood event bathymetric change to be visualised and also quantified.Despite the introduction (post-1998 floods) of engineered sediment management regimes in the Entrance and Reeves Channels, flood-tide delta accretion has continued. This sediment accretion potentially increases the vulnerability of infrastructure in low-lying areas of the Lakes Entrance township to any future Gippsland Lakes flood events.