Application of multi-hydrochemical indices for spatial groundwater quality assessment: Ziway Lake Basin of the Ethiopian Rift Valley

The Ethiopian Rift Valley (ERV) is characterized by arid and semi-arid climate with groundwater as the most important water resource used for drinking irrigation purposes. However, in region, people are suffering from severe scarcity exacerbated effect. Besides availability, endemic quality issues critical affect suitability of human health risks. present study evaluates agricultural purposes Ziway Lake Basin (ZLB) ERV. Groundwater contains multiple inorganic contaminants levels that surpass World Health Organization recommended limits. frequent these violations were Na+, K+, HCO3−, F− few samples Mn, As, U, Pb Mo. modeled Drinking Water Quality Index (DWQI) values show wide variation ranging 12.7 (Excellent category) to 714 (Unsuitable mean value 94. Likewise, Irrigation (IWQI) computed considering EC, SAR, Na%, RSC PI varies 13.2 520 a 106. Both DWQI IWQI suggest generally Excellent use headwater regions ZLB progressively becomes extremely Unsuitable toward rift floor. exceptionally high west mainly associated co-occurrence toxic elements Quaternary sediments rhyolitic volcanic aquifers.