Sediment Transport

Ocean sediments (e.g., sand, silt, minerals) come from rivers and coastal erosion and are naturally moved around by tidal flows and waves to fulfill necessary ecosystem processes. As offshore wind and marine renewable energy devices are placed in the water, it is likely that changes in flow will occur around the new obstruction due to energy removal and alter the previous pattern of sediment transport. Bottom-mounted devices will typically cause sediment deposition behind the device, remove sediment along the sides of the device, and show localized scour directly around the device footings. While the effects of individual devices may be very small on the nearby physical environment, arrays may have a greater impact on ecosystem processes. Numerical models are often used to estimate changes in sediment transport. However, it is difficult to quantify changes in the marine environment which has so much natural variation, especially with so few devices currently deployed in the water.