Shoreline dynamics of Calypsostranda (NW Wedel Jarlsberg Land, Svalbard) during the last century

A 6 km long stretch of the coast of Calypsostranda between Skilvika and Joseph-bukta, situated on the western side of Recherchefjorden, was investigated. It is made of an accumulative marine terrace at a height of 2-8 m a.s.l. (terrace 1) and width of 40-180 m, divided by a cliffed section in the frontal moraines of Renardbreen. From the character and intensity of changes, the area was divided into 6 zones. The aim was to analyse the dynamics of changes within coastal zone from 1936 to 2007 and to characterise the influence of various morphogenetic factors (marine, fluvial, cryospheric). The important element of this study has been to determine sources and directions of sediment transport. The dynamics of changes of coastal zone in the Calypsostranda region was established from archival maps and precise GPS measurements for the periods: 1936-1960, 1960-1990, 1990-2000, 2000-2005, 2005-2006, 2006-2007. Comparing the extension of shoreline between 1936 and 2007 showed that there was more erosion than accumulation. Nearly 110 000 m2 of the area of terrace 1 decreased, whereas about 77 000 m2 appeared. The net balance for 1936-2007 was about -32 700 m2, on average over the whole length of the shoreline, it retreated by 5.7 m (0.08 m a-1). The cease of sediment delivery in the extramarginal sandur fans area of Renardbreen caused intensification of marine processes, that made the shoreline retreat by over 100 m. Continuing sediment delivery from the Scottelva catchment, with contribution of material from erosion of the north end of the shoreline studies, caused the aggradation of coastal zone by over 60 m near its mouth.