The project will use novel analytical techniques/instrumentation to accurately quantify, for the first time, key proximal stressors associated with dredging/spoil disposal (i.e. sedimentation, light quantity/quality, suspended sediment concentrations) and will determine how these parameters vary with increasing distance from dredging. We will then test the response of corals, sponges, seagrass and algae to environmentally relevant/realistic conditions over appropriate time-frames. Matrices of hard data will be generated to derive water quality thresholds for key habitat forming organisms and for use as input parameters for pressure field modelling (including cumulative-impact modelling). This will dramatically improve risk assessment processes, provide greater surety for regulators and proponents, allow more informed decision-making and inform future dredging policy.