Qualitative Zoning of Shahr-e-Babak Aquifer Based on its Corrosiveness, Sedimentation, and Applicability for Agricultural, Drinking, and Pressure Irrigation Uses

Water quality management in groundwater aquifers requires accurate water quality monitoring to ensure they meet a variety of relevant standards. Given the rather few reported studies in the field, the present study was designed and implemented to investigate the groundwater quality of Shahr-e-Babak aquifer that is exploited for agricultural, mining, drinking, and industrial consumptions. The kriging and IDW (power:1-3) techniques with spherical, exponential, and Gaussian variogramsare were compared using R2, RMSE, MAE, and RSS indices to find the optimum model for determining the spatial variability of sixteen groundwater quality parameters. Multi-purpose zoning of groundwater quality was accomplished in the ArcGIS environment in terms of the Wilcox, Schuler, drip and sprinkle irrigation as delineated by Iran Power Ministry, corrosiveness, and sedimentation standards as well as the WHO and IRISI indices before spatial correlations were determined accordingly. Based on the water quality zoning maps thus derived, Langelier, Corrosiveness, and Ryznar indices were several times larger than the threshold levels across the whole aquifer plain, indicating the wide corrosiveness of the water in industrial applications. The results also revelaed that 93% of the groundwater in the plain area was classified as C4-S1 and C4-S2, which are unsuitable for irrigation, while only 1.3% of the groundwater was acceptable for drinking uses. Drip irrigation zoning revealed that 64% of the plain area had the lowest water quality.The undesirable quality zones in a vast area of the aquifer investigated calls for accurate quality monitoring and management to meet the development objectives in the region.