MONITORING OF SOME CHANGES IN MANZALA LAKE USING REMOTE SENSING AND GIS TECHNIQUES

Abstract

Manzala Lake is one of the largest lakes in the north of the Nile Delta of Egypt and it is the most important source of fish production. The lake is exposed to many impacts by human activities, such as drying some parts of the lake to be used as agricultural and urban areas as well as the deduction of large parts of the lake for fishponds establishment. This study aims at monitoring the changes occurred to the lake at different time intervals using the analyses of multi temporal satellite images of sensors LANDSAT-1 MSS, LANDSAT-5 TM, SPOT-4, and Sentinel-2A for years 1972, 1984, 1991, 2006 and 2017. Normalized Difference Water Index (NDWI), Modified Normalized Difference Water Index (MNDWI) and supervised maximum likelihood classification were used. Results showed that Manzala Lake area decreased by more than 60 % during the study period from 1972 to 2017. Derived areas of Manzala Lake at the studied periods from 1972 to 2017 were classified according to land cover classes using supervised classification approach to 4 main classes: cultivated areas (about 75051 fed), bare areas (about 65673 fed), urban areas (about 1338 fed), and fishponds (about 83721 fed). Comparing the results of the lost areas of the lake through the period 1972-2017 with the total area of land cover classes derived from the lake in the same period, it is found that a difference between the two areas is about 629 fed. (0.2 % of the total area of Manzala Lake in 1972) it can be considered that these soils were eroded and lost from the lake by the Mediterranean Sea effect.