Coupling support vector machine and the irrigation water quality index to assess groundwater quality suitability for irrigation practices in the Tana sub-basin, Ethiopia

Abstract

Long-term and sustainable agricultural practices can be achieved through monitoring and evaluation of groundwater quality for irrigation operations. However, less attention was given to irrigation water quality in the Tana sub-basin, Ethiopia. The present study is aimed to assess the seasonal and spatial groundwater suitability for irrigation uses. The groundwater quality parameters measured in 40 samples in each dry and wet season were the pH, electrical conductivity (EC), Na+, Ca2+, Mg2+, K+, Fe2+, HCO3-, CO32-, Cl−, and NO3-. The groundwater suitability for irrigation was assessed using the irrigation water quality index (IWQI) and support vector machine (SVM). The results showed high and medium irrigation suitability classes in the dry and wet seasons. The proportion of groundwater samples in the medium irrigation appropriateness class in the dry and wet seasons, respectively, was 72.5 and 67.5%. The groundwater in the wet season is comparatively more suitable than that in the dry season, which is attributed to the leaching of accumulated salts during the wet season. To avoid a salinity threat, vigilance should be exercised when using groundwater during the dry seasons. The groundwater quality suitability map developed here for irrigation may aid in locating better-quality groundwater sources for irrigation.