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

• Published in: Water practice and technology Vol. 17; no. 5; pp. 1129 - 1145
• Main Author: Tembo, Malugu M.
• Format: Journal Article
• Language: English
• Published: London IWA Publishing 01.05.2022
• Subjects: Anions; Aquifers; Catchment area; Catchments; Cations; Chemical oxygen demand; Cities; Drinking; drinking purpose; Drinking water; Economic development; Evaporation; geochemical processes; Geochemistry; Geographic information systems; Groundwater; Groundwater irrigation; Groundwater quality; History; hombolo catchment; Indicator organisms; Industrial development; Ion exchange; Irrigation; percentage soluble sodium; Permeability; permeability index; Precipitation; Rural development; Sodium; sodium adsorption ratio; Sustainable development; Urbanization; Water quality; water quality index and irrigation purpose; Tanzania
• ISSN: 1751-231X; 1751-231X
• DOI: 10.2166/wpt.2022.049

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.