Impact of an Exoreic Basin Dam on Shoreline Evolution at El Hamdania Beach, Northern Algeria: Insights from Statistical Methods and a Kalman Filter

Coastal monitoring is crucial for integrated coastal zone management, specifically for technical aspects of maritime infrastructure development and socioeconomic considerations related to coastal tourism. This study examines the recent evolution of El Hamdania beach’s coastline near Tipaza, northern Algeria, investigating the influencing factors and predicting future evolution of this beach. The study area was selected due to its socioeconomic importance as the proposed site for a major international port development project, in which coastal stability is critical for infrastructure development. Landsat and Sentinel satellite imagery data were analyzed through the digital shoreline analysis system (DSAS), and our investigation revealed two distinct coastal evolution periods: (1) from 1984 to 1990, stable coastline due to the equilibrium between wave-induced erosion and sediment supply from Wadi El Hachem; and (2) from 1990 to 2022, significant erosion (50–135 m) with an average rate of 2.5 m/year (calculated via endpoint rate method). Linear regression rate projections showed continued substantial shoreline retreat over the next 10–20 years. This high erosion rate is controlled by two main factors: (1) continued beach exposure to wave-induced longshore transport and (2) severe reduction of sediment supply from Wadi El Hachem following the Boukourdane dam construction in 1990. Lithological analysis of beach sediments supports this finding, confirming their provenance from sedimentary rocks outcropping throughout the Wadi El Hachem watershed. Results found using this methodology were compared to two field-measured shorelines for 1988 and 2018 to validate extracted shorelines from satellite imagery and DSAS analysis.