Contemporary geomorphic evolution of Falcon Cape sandy coastline (Oran, Algeria): geographical information system (GIS)-based approach

Abstract

This study focuses on the quantification and analysis of geomorphic changes along the sandy coast of Falcon Cape (north-west of Algeria) over a long period. This analysis concerns the processing of aerial photographs and satellite imagery from 1959 to 2018 (i.e., 59 years) and the topographic maps and digital elevation model (DEM) from 1934 to 2014 (i.e., 80 years). The evolution of this coast is particularly complex due to the interaction of several natural factors such as wind, drift currents, tides, and waves, as well as anthropogenic factors such as urbanization, shore protection, and sand extraction that have led to major geomorphological and sedimentary disturbances, manifested by the degradation of coastal dunes, and accelerated beach erosion, exposing human stakes to coastal hazards. In order to assess and map these changes, we followed a methodological approach that relies on a geographical information system (GIS). The evolution of the shoreline position was studied by aerial photographs of different missions (1959, 1980 and 2003) and a Google Earth Pro scene (2018), to highlight erosion, progradation, and/or stability from the shoreline. Also, the evolution of the dune-system morphology was based on the comparison of different topographic surveys (1934, 1959, 1985, and 2014), which were interpolated by Kriging. The result shows that the study area is in a state of erosion, with a rate of − 15.43 m on the Ain El-Turck bay and − 12.67 m at Bousfer-Andalouses bay, from 1959 to 2018, also, a massive decrease in the dune volume, with a deficit sedimentary balance of − 28.56 million m3 from 1934 to 2014.