Wollongong City Council, Shellharbour City Council and NSW Department of Climate Change, Energy, the Environment and Water engaged a consultant to undertake a contemporary bathymetric survey of Lake Illawarra and its tributaries followed by a comparative assessment with the 2008 bathymetric survey. This bathymetric survey was conducted to enable an analysis of sedimentation and erosion within the lake based upon historical data. There were four different techniques used - Real Time Kinematic (RTK) by foot, RTK by boat, Single Beam (SBES) by boat, and Multi Beam Echo Sounders (MBES) by boat. Data collection was conducted as close as possible along historical survey lines (2008) so that a comparison could be made during analysis.

This project provides information on the current status and recent changes of the topography of the Lake's bed, indicating the depth of water across the Lake. The comparative results determined if and where sedimentation and/or erosion is occurring.