Maps, aerial photographs, orthophotos and GPS data as a source of information to determine shoreline changes, coastal geomorphic processes and their relation to hydrodynamic conditions on Osmussaar Island, the Baltic Sea

The objective of the paper is to demonstrate the use of various cartographic, photographic and GPS sources in assessing shoreline changes in order to study coastal evolution in relation to temporal variations in climatic and hydrodynamic conditions. The study focuses on Osmussaar Island, NW Estonia. The combination of increasing storminess and a decrease in sea ice have led to the vitalization of coastal processes and changes in the existing equilibrium of coastal evolution in the recent decades. The island is slowly retreating on the northern side and migrating seaward in the southern part. The rate of coastal change in 1980s and 1990s has increased six times compared the previous decades. As a result, erosion has begun to occur in a zone which previously saw primarily sediment transport. Furthermore, even though the rate of shore changes has decreased during the last decade, it still exceeds twice that of what was measured before the 1980s. Field experiments with painted sediments have showed that the waves are capable of transporting gravel-pebble even at depths of 4 m.