Development of Irrigation Water Quality Index for Wadi Araba Basin, Southern Jordan

This paper attempts to evaluate the quality of irrigation water regards to potential soil, crop problems and irrigation types for specific use. For this purpose, the Water Quality Index for irrigation (IWQI) was introduced which is a technique that can be used to classify irrigation waters with respect to three suitability classes and three degrees of restriction on use. The objective of this index is to transform complicated water quality data into information that can be utilized by the public. The IWQI was used to identify the irrigation water along Wadi Araba area in southern Jordan. Irrigation water quality was assessed based on salinity hazard, sodium hazard (soluble sodium percentage and sodium adsorption ratio, bicarbonate hazards (residual sodium carbonate), magnesium hazard, permeability index, Kelly’s ratio, chloride hazard and boron hazard. The spatial distribution of water quality index (WQI) map has been prepared using ArcGIS 10.2 in which 59.5% of groundwater used for drinking purposes was classified as poor water category, where 75.7% of the water has a medium suitability based on irrigation water quality index. Moreover, the Wilcox’s diagram was used for classifying the irrigation water based on the salinity and sodium hazard, where 67.6% of the groundwater have permissible to doubtful irrigation water quality due to the presence of high salinity and low sodium hazard ( Class C3S1).