Journal Article

Assessing the spatiotemporal transformation of a coastal lagoon inlet (1984–2019) using remote sensing and GIS: a study of Khenifiss Lagoon in Southern Morocco

El Behja, Hamza, Nachite, Driss, El M’rini, Abdelmounim, Abioui, Mohamed

2024

Overview

Coastal lagoons are highly dynamic ecosystems that are continually changing in shape and size due to natural processes. This study used satellite imagery, remote sensing, and GIS mapping, along with historical wind and wave data, to comprehensively explore the long-term changes occurring at the Khenifiss Lagoon entrance and its downstream main channel, which is one of the most important wetlands protected by the Ramsar Convention in Morocco. By employing thorough image selection, rigorous corrections, and intricate processing and analysis techniques, this research shed light on the evolution of sediment deposition areas, eroded zones, vegetation coverage, and locations, where dune influence affected sedimentation in this dynamic coastal ecosystem. The investigation spanned from 1984 to 2019 and relied on the analysis of Landsat optical images gathered in 1984, 1990, 2000, 2009, and 2019. During the study period, the entrance to the Khenifiss Lagoon (Foum Agouitir) gradually enlarged, increasing from 1450 m in 1984 to 1650 m in 2019. Concurrently, vegetation coverage within the lagoon's entrance and main channel increased from 53.54 hectares in 2009 to 103.9 hectares in 2019, resulting in a significant decrease in total water body extent. Sediment deposition impacts 206 hectares, considerably surpassing the erosion-affected area of 99.14 hectares. This significant difference emphasizes the rising dominance of sedimentation over erosion at the Khenifiss Lagoon entrance zone. The processes of sedimentation within the lagoon are largely influenced by the dune's advance, which has resulted in silt deposition over an area of approximately 57.39 hectares. These findings highlight the lagoon's exposure to progressive closure and strongly support the need to start a monitoring program to evaluate the lagoon's changing condition, especially at the entrance and the main channel. This study puts forth several recommendations for implementing management strategies aimed at ensuring the sustainability of this coastal ecosystem.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Biogeosciences / Coastal dynamics / Coastal ecosystems / Coastal lagoons / coastal water / Deposition / Dunes / Earth and Environmental Science / Earth Sciences / Ecosystems / Environmental Science and Engineering / evolution / Geochemistry / Geographic information systems / Geographical information systems / Geology / Hydrology/Water Resources / Inlets (waterways) / Lagoons / Landsat / Landsat satellites / Long-term changes / Morocco / Original Article / Plant cover / Remote sensing / Satellite imagery / Sediment / sediment deposition / Sedimentation / Sedimentation & deposition / silt / Soil erosion / surface water / Terrestrial Pollution / Vegetation / Water bodies / Wave data / Wetlands / wind