This document investigates whether the presence of the Oyster WEC array is likely to impact the natural erosion and sediment transport processes in the vicinity of the development area. Particular attention is given to the potential for impacts to the Skara Brae World Heritage site, and other sensitive receivers in the vicinity. Aquamarine Power Ltd is currently developing a hydro-electric wave energy converter (WEC) called Oyster. The Oyster is located in shallow water close to the shore. The WEC consists of a bottom-hinged, surface-piercing flap which oscillates due to wave action. Double acting pistons on each side of the WEC pump water through a high pressure pipeline to a hydro-electric plant on the shore. The high pressure water drives a Pelton wheel turbine connected to an electrical generator. The flow from the Pelton wheel discharges to a header tank and returns to the WEC via a low pressure return pipeline.