Groundwater Suitability for Sustainable Irrigation in the Arid Béni Ounif Syncline, Southwestern Algeria: Salinity Hazards, and Irrigation Water Quality Indices

Abstract

Groundwater is a strategic resource for irrigated agriculture in arid regions, where severe water scarcity and high evaporative demand constrain sustainable crop production. This study evaluates the suitability of groundwater in the Béni Ounif syncline, southwestern Algeria, for agricultural irrigation using 46 groundwater samples collected from the shallow and Continental Intercalaire (CI) aquifers. Irrigation quality was assessed through electrical conductivity (EC), sodium adsorption ratio (SAR), soluble sodium percentage (SSP), Kelly’s ratio (KR), permeability index (PI), potential salinity (PS), magnesium adsorption ratio (MAR), and the irrigation water quality index (IWQI). Results indicate low sodium hazard, with all samples classified as excellent according to SAR. IWQI classified all CI samples as good, while shallow-aquifer waters were 63.33% good and 36.67% excellent. However, high-salinity conditions occurred in 62.5% of CI and 26.67% of shallow samples, highlighting the need for drainage, leaching, and salt-tolerant crops for sustainable agricultural water management under prevailing local conditions.