WID Performance Evaluation

A multi-disciplinary study was organized during July 2005 to evaluate the performance of Water Injection Dredging in the Jellingham channel of the Hugli Estuary. Two locations were selected for conducting the study – one near the Oil Jetty and the other in the middle of the Jellingham channel.  The experiment was to conduct Water Injection Dredging at these locations, during ebb tide and analyse its effect with the help of different techniques including Multibeam bathymetry, Parametric Sub-bottom Profiling and Sidescan Sonar.

Benthos C-3D has been used for a test survey at Haldia on 22.08.2004, after the replacement of the faulty bottle (containing the electronic components) with a new imported one.  It worked continuously for about nine hours with two stoppages and automatic restart (within less than a minute). The sensor was being towed at the starboard side of the survey vessel (Siyaram).   The following have been observed from the survey and processing of the data:  1) A sufficient minimum depth is required for the bathymetry system to work properly.  2) Fix mount and associated correction procedures (as required for a full fledged bathymetry survey) are needed for achieving bathymetric accuracy.