Geochemical processes influencing groundwater quality for drinking and irrigation uses in Hombolo catchment

Abstract

This study identifies the major geochemical processes that regulate groundwater quality in the Hombolo catchment to make it suitable for drinking and irrigation purposes. The major cations and anion concentrations were used to develop the major geochemical processes governing the groundwater quality. The major geochemical processes were evaluated using historical data gathered from 1983 to 2018. The developed geochemical processes indicated the mineral dissolution, ion exchange and evaporation were the dominant that influence groundwater quality in the catchment using mole ratio concept and Gibbs diagram. The suitability of groundwater for irrigation was evaluated using the permeability index (PI), sodium adsorption ratio (SAR), and percentage soluble sodium (PSS) while the suitability of groundwater for drinking was evaluated using the water quality index (WQI). The sodicity indicated to have the average SAR of 5.16 as excellent class, average PSS of 50.89 as permissible to good class and average PI of 74.47 as suitable class level. The groundwater for drinking use indicated the WQI of 104 as poor class level. The groundwater is suitable for irrigation activities but the quality for drinking is deteriorating with time. HIGHLIGHTS The geochemical processes governing groundwater chemistry are explained.; In turn, it raises the community's attention about the groundwater quality problems and pushes them to avoid practices that contribute to the deterioration of groundwater quality near the groundwater resources.; It assists policymakers and management personnel in better utilizing the gathered pieces of information for better groundwater management.;

Keywords

• drinking purpose
• geochemical processes
• hombolo catchment
• percentage soluble sodium
• permeability index
• sodium adsorption ratio
• water quality index and irrigation purpose