Monitoring the Environmental Changes of Mariout Lake during the Last Four Decades Using Remote Sensing and GIS Techniques

摘要

Multi-dates satellite images have been used in this study to detect the trends of environmental changes in Mariut Lake, particularly for the main two lake ecosystems; water, and vegetation. The study focuses on the aquatic vegetation type and water area of Mariout Lake during the past four decades (from 1972 to 2016). The results reported in this research represent the way in which ecosystem degradation processes, affecting Lake Mariout, are increased due to external factors (human activities) of drying and reclaiming some areas to estimate the consequential effects on the lake. A combination of LandSat-1(MSS), LandSat-5 (TM), LandSat-7 (ETM+), SPOT-1, SPOT-4, SPOT-5, Rapid Eye, and Sentinel-2 Satellite data were used to analyze temporal changes in the Lake ecosystem. Different image processing techniques were under taken such as: on screen digitizing to delineate the lake boundary, the Normalized Difference Water Index (NDWI) makes use of reflected near-infrared radiation and visible green light to enhance the presence of such features while eliminating the presence of soil and terrestrial vegetation features, and change detection to ascertain the changes of water and vegetation features within last Four decades interval. The results of analysis indicate that Mariut Lake has been subjected to various physical and biological changes mainly due to the different human activities that have serious impacts on its quality and a subsequent deterioration in its ecological parameters.