摘要：The purpose of this study is to investigate the effect of using Bicarbonate and Calcium parameters as alternatives to the lithostratigraphic units covered the catchment area, on water quality index (WQI) values that have been implemented with GIS technique at Wadi Al-Arab Dam. The analyzed results (by WQI method) have been used to depict water quality for the two approaches. Based on physico-chemical parameters, the calculated values for WQI over the 3-year for study period were 169, 168, and 157, respectively. While the WQI values were 184, 183 and 172, respectively, as a result of incorporated Bicarbonate and Calcium parameters in WQI calculations that significantly contributed to increasing the WQI. The elevated values may be attributed to the influence of carbonate stone dissolution and mechanical erosion under weathering conditions that are prevalent during winter season in the catchment area. As a consequence of lithostratigraphic unites product and GIS technique integration and normalization processes, most of water quality ranks are good and only autumn season has poor water quality in the 2012 and 2013, while in 2014 it has good water quality in the same season. The WQI values increase in general trend from winter to autumn seasons during the study period that may be referred to outflow by daily consumption, evaporation rising, and seepage water. The analysis shows that the modified water quality values of the Wadi Al-Arab Dam Reservoir (WADR) vary after using Bicarbonate and Calcium parameters by constant value. Generally, the results signify that the WADR is not polluted based on the physical and chemical characteristics of water.
