ASSESSMENT OF EXTENT OF SHRINKAGE OF LAKE CHAD USING REMOTE SENSING TECHNIQUE
Publication Date : 10/07/2020
Lake Chad commonly serves as a major hub of fertile economic activities for the border communities and contributes immensely to the national growth of all the countries that form its boundaries. However, incessant and multi-decadal drying via climate change pose greater threats to this transnational water resource, and adverse effects on ecological sustainability and socio-economic status of the catchment area. Therefore, this study assessed the extent of shrinkage of Lake Chad using remote sensing technique. Landsat imageries of the lake and its surroundings between 1999 and 2019 were retrieved from Global Land Cover Facility website and analyzed using ERDAS Imagine 2014 version. Supervised classification of area around the lake was performed into various land use /land cover classes, and the shrunk part of its environs was assessed based on the land cover changes. The shrinkage trend within the study period was analyzed. The lake water size reduced from 186824 to 100409ha which implies that the percentage increase in reduction of the water size is (7.83-12.03%) in 1999-2019.The supervised classification of the Landsat imageries revealed an increase in portion of the lake covered by bare ground and sandy soil within the reference years (116295-208713ha) with 15.17% total range of increase. The lake portion intersected with vegetated ground and soil also increased within the period (116295-208713ha) with 15.17% (92418ha) total increase. The shrunk part of the lake covered singly with vegetation increased by 4.46% from 1999 to 2010 and decreased by 20.96% from 2010 to 2019.The shrunk part of the lake reduced to sand and turbid water showed 19.24% decrease from 1999 to 2010 and 18.16% increase from 2010 to 2019 a total decrease of 330841ha. The study disclosed an appalling rate of shrinkage and damaging influences on the hydrologic potential, eco-sustainability and socio economics of the drainage area as revealed using ERDAS Imagine 2014. This study will be very useful to policy makers in the country and the West Africa sub regions on the precautionary steps to be taken to avoid Lake Chad region going into extinction knowing the importance such lake occupies not only in West Africa, but in sub-Sahara Africa.
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