Coastal Sedimentary Dynamics and Land Use Occupation of the Sabkha in Semi-arid Region

This framework aims to monitor the sediment dynamic evolution and land use occupation of the coastal salt-lake system—Sabkha of Ariana—extended in semi-arid region in the gulf of Tunis in Tunisia. We adopted a sedimentary analysis of the sediment crust from the landward to the coastal ridge in winter 2020. Land cover/land use (LCLU) assessment was based on different Remote Sensing (RS) data-scenes of Landsat 5 and 8 for the years 1972–1984–1985–1994–2010 and 2020, completed by the aerial scenes (1974s) and the K-means clustering. In coastal area, grain size distributions show medium to fine sand, well-sorted and which are mostly unimodal. The sabkha crust distribution reveals silty-clay logarithmic-shaped facies of turbidite channel deposit in shallow-water calm environment. The change detection of LC between 1985 and 2020 reveals a decrease of vegetation classes by ~ 27%, the sandy deposit by 7% and an increasing trend by 15% and 22% of bare soil and the urban areas, respectively. Diachronic assessment of the sabkha landscape from 1972 to 2020 datasets revealed the expansion of the salt-flat crust from 19 to 27 ha. Both the global aridification and the urbanization impacted the natural dynamics of the coastal sabkha, resulting in decreasing trend of the vegetation covers and natural features in favor of the salt flats and urban spaces.