Evaluation of Surface Water Quality Variation for Irrigation Suitability in Dodota Dragline Sprinkler Irrigation System, Ethiopia

The sustainability of irrigation schemes like dragline sprinkler irrigation systems depends on irrigation water quality. This study evaluated the physicochemical characteristics and irrigation suitability of Awash River water used in the Dodota Dragline Sprinkler Irrigation System. A total of 21 water samples were collected from seven sequential hydraulic monitoring points during three dry‐season sampling periods. About 17 water quality parameters were analyzed using standard laboratory procedures. Irrigation suitability was assessed using sodium adsorption ratio (SAR), soluble sodium percentage (SSP), permeability index (PI), Kelly ratio (KR), residual sodium carbonate (RSC), Langelier saturation index (LSI), and irrigation water quality index (IWQI). Results showed that electrical conductivity (EC) ranged from 0.45–4.7 dS/m and SAR from 0.59 to 2.65. Total dissolved solids (TDS) ranged from 314 to 3000 mg/L, while total suspended solids (TSS) varied between 23 and 200 mg/L, chloride concentrations ranged from 1.2 to 13.6 meq/L, potassium from 7.42 to 20.63 mg/L, chromium concentrations ranged from 0.02 to 0.15 mg/L, and bicarbonate from 4 to 12 meq/L and LSI values ranged from 0.02 to 1.53. The IWQI values ranged from 46.69 to 83.81, where 38.1% of the samples were classified as low restriction, 57.1% as moderately restricted, and 4.76% as highly restricted for irrigation use. The findings indicate that Awash River water is suitable for dragline sprinkler irrigation under proper management practices. However, concentrations of TSS, chloride, chromium, bicarbonate, and potassium at some monitoring stations may increase the risks of nozzle clogging, and long‐term soil quality deterioration. Therefore, appropriate pretreatment measures, regular quality monitoring, and effective upstream pollution control are recommended to improve irrigation system performance and maintain soil productivity.