Hydrosalinity and environmental land degradation assessment of the East Nile Delta region, Egypt

Environmental land degradation is a major impediment to the utilization of land in many arid and semi-arid regions of the World and is a major issue in the East Nile Delta (END), Egypt. Waterlogging and salt-affected soil problems have serious implications for irrigated areas leading to socio-economic and agricultural development problems. In the present study, timely and accurate detection of land degradation through remote sensing and hydrosalinity indicators, along with their characteristics and severity classification in a GIS environment, has been undertaken to provide, determine, assess and map reliable geo-information of environmental land degradation. This research deals with an assessment of hydrosalinity and environmental land degradation based on some new, but simple and practical, approaches for assessing salinity and spread of land degradation through digital image processing, geo-statistics and geochemistry. This analysis utilises Landsat 8, ASTER GDEM data, hydrochemical and statistical analyses using a GIS, together with other field collected data sets for the same date of May 2014. The hydrosalinity mapping and the statistical data analysis of TDS, major ions, groundwater grouping and hydrochemical facies and also water table maps between 1994 and 2014 reveals that the main sources of groundwater recharge and water bodies are mostly attributed to the continuous seepage from newly cultivated lands. The new flow regime is the main contributing factor to the rising water level, water salinity and waterlogging problems. Moreover, the spatial distribution of major ion content could be attributed to the leaching of aquifer materials along the flow path (Na, Ca, and Cl), the study area affected by agricultural pollution (Mg and SO4) and the leaching process which acts on the easily soluble evaporate-rich fluvio-marine sediments of a shallow aquifer (NO3 and PO4). The spatial distribution maps of the physico-chemical properties of soil such as EC, pH, SAR, Na, Cl, SO4 and Ca are compared with remote sensing salinity indices and then integrated to classify and map the salinity and salt-affected soil by using GIS tools. These indicate that increases in soil salinity levels pose a serious threat to sustainable agricultural developments that requires special attention to maintain an appropriate soil–water plant relationship by providing an adequate drainage system. The identification of land degradation mitigation measures requires thorough knowledge of the ground and surface water, human activities, and the salinity dynamics of the study area.