Linking wave loads with the intensity of erosion along the coasts of Latvia

Numerically estimated wave properties and the associated closure depth along the eastern Baltic Sea coast from the Sambian (Samland) Peninsula up to Pärnu Bay in the Gulf of Riga are compared against the existing data about accumulation and erosion. Typical values of the closure depth are about 5-6 m (maximum 6.58 m) at the open Baltic Sea coast, 3-4 m in the Gulf of Riga and 2-2.5 m in semi-sheltered smaller bays. The areas of intense accumulation or erosion (especially the areas of their high variability) generally coincide with the sections, hosting high wave intensity, except for a few locations, dominated by anthropogenic impact. It is shown that the longshore variations in wave intensity (or closure depth) can be used to identify the location of major accumulation and erosion domains. The sections that host the largest change in the wave height along the coast reveal erosion or accumulation features, depending on the predominant wave approach direction.