SWAT (Shoreline plastics in Waves and Tides)

The understanding of processes governing the distribution of plastics pollution on beaches is currently an underdeveloped field of study but one with huge potential impact. Current models for plastics transport in the marine environment tend to use very simplified descriptions of the plastics-shoreline interaction. However, the stranding process is clearly a very important component of a model, both due to the direct interest in plastics on beaches and because of the impact on the overall transport due to beaching and resuspension.  Hence, experimental lab data and comparisons with observed beach litter is necessary for further understanding and model development for processes governing the distribution of plastics accumulation.

Here we investigate the mechanisms controlling the accumulation of plastic pollution upon an artificial beach.  Weakly buoyant plastic “nurdles” are placed within a linear wave flume with a sloping sandy beach. The water level is changed to emulate tides, and randomly generated waves are sent towards the beach. The distribution of particulates is imaged using a downward facing camera above the beach.  Image analysis is then used to determine the varying concentration of plastics, as a function of time, over varying wave and tide conditions.