The world’s best known estuarine lagoon not only has historically importance for sheltering the City of Venice but is a fascinating ever changing environment with only 8% covered by land, 12% by open water and the remaining 80% by mud flats, tidal shallows and salt marshes. This geographical setting, hosting complex ecosystems, is influenced by tidal cycles entering through three sea inlets and freshwater and sediment supplied by river influx.
Monitoring of changes to the environment is becoming ever more important with changing sea levels and as the human impact increases with the MOSE flood protection project enabling the closing of the sea inlets and dredging activities.
The Venice Institute of Marine Science (ISMAR-CNR) is engaged in research and monitoring projects of the lagoon. Kongsberg Geoacoustics was invited recently by the institute to demonstrate their technology for gathering high resolution bathymetry data with the aim of effectively covering large very shallow water areas with portable installation, providing highly repeatable data to allow monitoring of even smallest changes through time.
Kongsberg Geoacoustics GeoSwath Plus Compact was chosen due to its capabilities to gather data up to the waterline with a coverage of up to 12 times the water depth in shallow water environment. Repeat surveys were carried out and showed to be consistent albeit the difficult hydrological conditions with large tidal currents and fresh water mixing, leading to high temporal and lateral sound speed variations. In addition the system offers true co-registered and geo-referenced side scan data which can be used for seabed classification and textural mapping.
[mappress] Subsea World News Staff , January 19, 2012; Image: Kongsberg