Forecasting of Groundwater Salinity Changes and Yield of Some Crops by Integration of Time Series Analysis and GIS at Wadi El-Natrun Area, Egypt

Wadi El-Natrun region has recently undergone extensive urban and agricultural expansion. The main water resource for irrigation in this region is the groundwater aquifer. Extensive use of the aquifer water could cause a shortage in water storage and secondary salinization for this water, and a crop yield reduction.  So, the objective of this study is to set efficient strategy to ensure long-term sustainability of the region’s agricultural production. The electrical conductivity (EC) database of the baseline period (1966-2014), for twenty-seven wells of Wadi El-Natrun, were used to apply the time series statistical analysis to forecast EC data of the future period (2015-2050). Multitemporal forecasted EC data was used to classify the groundwater, detect the annual and periodical changes of groundwater salinity, and determine the periodical and annual water potential risk to salinity hazards. The results of the forecasted EC data indicated that the category of very salty groundwater dominated in the northern sector, while the moderately salty and salty groundwater categories dominated in the southern sector. The annual changes of groundwater salinity increased through the period of 2015-2050. The increase ranged from 0.95% to 1.35% with annual mean of 1.13% for the southern and northern sectors. The forecasted EC and an innovative and interpretative scale were conducted to estimate the periodical (PPRSH) and annual (APRSH) water potential risk to salinity hazard of the future period (2015-2050). The results indicated that the classes of no risk and moderately potential risk were dominant in the southern and northern sectors. Regarding the crop yield, in 1966, about 68.80% of the area under investigation produced 100% of citrus yield and 30.62% of area produced from 75 to 99% of the yield, while 89.9% of area produces 100% of tomato yield and 10.1 % of area produce between 75 to 99% of yield. Based on the forecasted groundwater salinity in 2050, the area of 100% of citrus production will be reduced to 1.41% and 52.64% of the area will produce less than 75%. At the same time, 16.44% of the area become out of citrus production. The area of 100% of tomato production will be reduced to 27.3% and 38.15% of the area will produce less than 50%.