Shen Neng 1 grounded on Douglas Shoal in an area broadly described as the Lower Terrace. The Lower Terrace is a heterogeneous terrain characterized by depressions, undulations, gutters and sandy holes often called Melon Holes. Within and downstream of the grounding area these depressions are “likely filled” (Advisian Site Assessment Report 2019) with rubble created by the grounding forming a ‘sink’ for rubble and contaminated sediment under normal oceanic conditions and ‘source’ for this material during storms.

The Sandy Holes and Gutters data was derived by contouring a raster ARC GRID coverage of the Multi-beam sonar data captured by Advisian in 2019 and refining through visual inspection of the bathymetry raster. The Sandy Holes and Gutters dataset was used as stratification in a stratified sediment sampling plan to target areas of accumulated sediment. For further information relating to the survey and data refer to: Neale, S. J. and Boylson, B. D. 2019, Site Assessment Report - Douglas Shoal Remediation Project. Document 301001–02112-ENREP-0004, Revision 1. Report prepared by Advisian Pty Ltd for the Great Barrier Reef Marine Park Authority, Townsville, Queensland, Australia. 301001-02112-EN-REP-0004 - Site Assessment Report: Douglas Shoal Remediation Project.