Spatial and seasonal assessment of physico-chemical characteristics of soil in Wadi El-Rayan lakes using GIS technique

Abstract

AbstractWadi El-Rayan wetland is an inland Egyptian Ramsar site of international importance, due to its rich biodiversity. The wetland constitutes two man-made lakes. The lakes size, particularly the Lower Lake, is in continuous reduction, and the vegetation productivity pattern is changing as result of deteriorating water and soil quality, domestic and industrial activities. This research was carried out to map the spatial and seasonal distribution of certain physico-chemical parameters of geo-referenced soil samples covering the two lakes parts using ordinary kriging GIS technique. The study utilized ArcGIS ver.10.7 software, and 76 soil samples collected from representative sites; 38 samples during winter and 38 samples during summer seasons. Soil data were analyzed statistically and geo-statistically based on best fitted semivariogram model. The results indicated high concentrations of some soil physical and chemical parameters, especially in summer and in the Lower Lake of Wadi El-Rayan. The summary statistics for soil parameters had shown that the median of some soil parameters is higher than the mean which indicated the presence of abnormal data. This finding has been approved through the spatial distribution mapping which clearly showed the differences in spatial and temporal distribution between the upper and lower lakes of Wadi El-Rayan. The study concluded that the generated spatial distribution maps using ordinary kriging method can be used as an effective tool in Wadi El-Rayan wetlands’ soil management.