Abstract
In this study, the suitability of groundwater for irrigation purposes in Madinah city, Saudi Arabia was assessed. Of the 23 wells that were drilled in different locations of the city, 20 wells were sampled for water quality analyses. The United States Department of Agriculture (USDA) classification of irrigation water that is based on sodium hazard (SAR) and salinity hazard was used for irrigation suitability assessment. In addition, the residual sodium carbonate (RSC) and soluble sodium percentage (%Na) were calculated for all samples and also used for irrigation suitability assessment. Results showed that all groundwater samples are in the acceptable quality range for irrigation based on RSC values, and the majority of the samples had %Na in the acceptable range for irrigation. When SAR and salinity hazard were assessed, results showed that while almost all groundwater samples fell in the acceptable range of SAR, they were either in the high or very high salinity zones, indicating that the water can be used for irrigation after adopting some management practices. Comparing total dissolved solids (TDS) concentration obtained 35 years ago for the study area with the current TDS values indicates that the recent accelerated urban development in the study area did not significantly impact groundwater quality with regard to irrigation suitability.