Evaluation and mapping of groundwater quality for irrigation and drinking purposes in Kuhdasht region, Iran

Preservation of water quality, particularly in areas with inadequate water resources is considered as one of the principles of planning in integrated water management. In Kuhdasht, a region at the west of Iran, groundwater and spring water resources are the major contributors of drinking and irrigation water supply. The aim of this study was to determine the suitability and mapping of springs and groundwater for irrigation and drinking purposes based on the water quality indices. Values of physical (pH, electrical conductivity, total dissolved solids), and hydro chemical characteristics (Na+, K+, Ca2+, Mg2+, HCO3-, Cl- and SO4-) of springs and groundwater were identified. To assess the water quality, chemical parameters like sodium adsorption ratio (SAR), total hardness, Mg-hazard (MH), sodium percentage (Na%), and salinity hazard were calculated based on the analytical results. ANOVA test was used to compare the treatments of different stations’ quality parameters and LSD test was used to assess the statistical differences between the regions, for spatial distribution and mapping, geo-statistical interpolation techniques of Kriging method were applied. A Durov diagram plot showed that the groundwater has been evolved from Ca-HCO3 recharge water followed by mixing and reverse ion exchange processes due to the respective dominance of Ca – Cl water types. Based on Gibbs’s diagram plots, chemical weathering of rock forming minerals is the main factor controlling water chemistry in this area. Based on ordinary Kriging, most parts of the region has good water for the drinking and irrigation.