Environmental Applications of Geographical Information Systems

The objective of this study was to examine how semi-variograms can be used to model the spatial variability of water quality in Lake Manzala, Egypt. The lake has potential economic value not only to the local community but also to the national economy. The lake wetland habitats are rich in wildlife species. More recently, the lake has been subjected to abrupt changes in its water quality giving the most alarming example amongst the northern Egyptian lakes as a result of economic development, urbanization and population growth,urban agglomeration and land reclamation schemes. Spherical models were found to be a more successful estimator of water quality condition and were of support to traditional methods as an adequate tool to provide valuable spatial and temporal detailed information about water quality in the Lake. Ordinary Kriging provided good estimations of water quality parameters points in the lake where field sampling was limited and which can be of importance in future sampling schemes. The modeled distribution of water quality was presented in the form of digital maps based on both traditional sample data and variogram models.