The report aims to capture key messages and conclusions regarding dredge material management in the region that have resulted from the study. This report also identifies knowledge gaps and additional research that would further increase understanding of risks and potential management arrangements associated with dredge material placement in the World Heritage Area. What Does "Long-term" Mean? Consideration of time scale is essential at all levels of risk and impact assessment and environmental management. In this study, carried through to this report, "long-term" is applied on two different time scales, which may be thought of as strategic and technical: Strategic: The overall context of the study is aligned to the Strategic Assessment, i.e. the study has adopted a 25-year outlook. This 25-year perspective was adopted in consultation with the GBRMPA and port operators. The 25-year time frame has been used to develop outlooks for capital and maintenance dredging needs, and consequently the most relevant dredge material placement scenarios for investigation. SKM recognises that ports are expected to continue to operate on longer time scales of 50 years and beyond. It was not practical, however, to anticipate dredging requirements and other port-associated coastal developments on such a long time scale. Technical: The technical outputs of the study revolve around hydrodynamic modelling of the movement of dredge sediments. In this context, "long-term" refers to modelling over a period of 12 months from the commencement of the hypothetical placement scenario. This is the first study to incorporate the influence of large-scale currents to model dredge material movement over 12 months. Modelling dredge material movement on the 25-year strategic time scale is far beyond current technical capabilities.
The report aims to capture key messages and conclusions regarding dredge material management in the region that have resulted from the study. This report also identifies knowledge gaps and additional research that would further increase understanding of risks and potential management arrangements associated with dredge material placement in the World Heritage Area. What Does "Long-term" Mean? Consideration of time scale is essential at all levels of risk and impact assessment and environmental management. In this study, carried through to this report, "long-term" is applied on two different time scales, which may be thought of as strategic and technical: Strategic: The overall context of the study is aligned to the Strategic Assessment, i.e. the study has adopted a 25-year outlook. This 25-year perspective was adopted in consultation with the GBRMPA and port operators. The 25-year time frame has been used to develop outlooks for capital and maintenance dredging needs, and consequently the most relevant dredge material placement scenarios for investigation. SKM recognises that ports are expected to continue to operate on longer time scales of 50 years and beyond. It was not practical, however, to anticipate dredging requirements and other port-associated coastal developments on such a long time scale. Technical: The technical outputs of the study revolve around hydrodynamic modelling of the movement of dredge sediments. In this context, "long-term" refers to modelling over a period of 12 months from the commencement of the hypothetical placement scenario. This is the first study to incorporate the influence of large-scale currents to model dredge material movement over 12 months. Modelling dredge material movement on the 25-year strategic time scale is far beyond current technical capabilities.
gbr-dredge-material-management.docx