Modified irrigation water quality index for efficient water quality management of micro-irrigation systems

ABSTRACT The practical remedy to emitter clogging in micro-irrigation systems is essential owing to water pollution issues worldwide. This research presents a modified irrigation water quality index (IWQI) that integrates normalized tolerance values and weighted factors to simplify the interpretation of irrigation water quality data. Validated through emitter clogging experiments, the index offers a robust and accessible tool for assessing water suitability in drip irrigation systems. Emitter clogging was assessed by discharge ratio, clogging degree (C), and emitter's dried residue. C values were between 4.7 for unclogged and 6.3 for general clogging in categories I and V, respectively, which were attributed to electrical conductivity (EC), sodium percentage (Na%), and total suspended solids (TSS). A gradual decline in emitter discharge was observed at escalated pollution (1.77 to 1.26, 1.79 to 1.20, 1.78 to 1.50, 1.76 to 1.48, 1.77 to 1.19, 1.79 to 1.44, 1.78 to 1.58, and 1.78 to 1.54 L/H for EC, Na%, sodium adsorption ratio, total dissolved solids, TSS, pH, chloride, and calcium, respectively). By translating complex water quality metrics into an intuitive grading scale, this research facilitates informed decision-making among farmers, engineers, and policymakers for proactive water management by enhancing the micro-irrigation efficiency.