Beach profile change caused by vessel wakes and wind waves in Tallinn Bay, the Baltic Sea

Abstract

Beach dynamics resulting from the interplay of vessel wakes and background wind waves are studied experimentally using data obtained in 2008 in Tallinn Bay. The beach profile h is presented schematically as a power function of the coordinate x (distance from the coast) with an exponent b (h ~ xb). On the basis of field measurements, the parameter b has been presented as a function of time and studied as a beach characteristic with respect to changes in wave properties. The number of ship crossings does not change significantly from one day to another and the properties of ship induced waves are quite stable. Therefore we are able to focus our analysis on the changes in wind wave background. Special attention is given to the dependence on wave periods. It is shown that wind waves of longer period are more energetic and are able to accrete the beach which generally loses sediment due to ship wakes.