Integrated evaluation of groundwater irrigation suitability using hydrochemical indices and irrigation water quality index (IWQI) in Aksum, Tigray, Ethiopia

Abstract

Water, a vital natural resource for sustaining life, has experienced a sharp rise in consumption due to increasing demand. Although many studies evaluate groundwater hydrogeochemistry and drinking suitability, its agricultural suitability remains largely underexplored. Recognizing the importance of irrigation to local agriculture, this study integrates multiple hydrochemical indices with the IWQI to comprehensively assess groundwater suitability for irrigation in the Aksum area. This study evaluates hydrochemical parameters, including total dissolved solids (TDS), electrical conductivity (EC), sodium adsorption ratio (SAR), sodium percentage (Na%), permeability index (PI), Kelley index (KI), and residual sodium carbonate (RSC), and employs the irrigation water quality index (IWQI). Results revealed that SAR (0.07-1.09), Na% (2.5-17.19), RSC (- 7.79 to - 1.23), and KI (0.02-0.17) values of all water samples were suitable for irrigation. However, 5.26% of samples exceeded recommended limits for TDS (206.8-2774), EC (290-3890), and PI (19.76-52.94). The calculated IWQI values ranged from 72.3 to 100, averaging 94.6. About 94.74% of samples showed no restrictions, while 5.26% had low restrictions. Spatial maps reveal a northeast-southwest decline in irrigation water quality. However, groundwater remains generally suitable for irrigation. The findings improve understanding of sustainable water quality, guiding planners, policymakers, and stakeholders in effective irrigation management.