Browsing by Author "Kumar, Sudhir"

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Conceptualization of groundwater-surface water interaction with evidence from environmental isotopes and hydrogeochemistry in lake Babati Basin in Northern Tanzania
(Elsevier, 2023-05) Okwir, Gustavio; Kumar, Sudhir; Pramod, Kumar; Gao, Hongkai; Njau, Karoli
The holistic management of water resources is attainable with evidence-based planning constructed on reliable hydrological information. However, data paucity, especially in sub-Saharan Africa, leads to a significant knowledge gap regarding surface water and groundwater interactions, leaving considerable uncertainty to support relevant decisions. This study combined hydrogeochemistry and environmental isotopes to explore the connections between the surface water and groundwater in the data scarce catchment of Lake Babati Basin in northern Tanzania. The results showed that: i) Lake Babati receives groundwater influx from recently recharged aquifers endowed in the pyroclastic formation in the lake basin; ii) the lake is not well mixed as presented by the heterogenous hydrogeochemistry and confirmed by the differences in the isotopic composition of deuterium and oxygen – 18 at different locations within it; iii) the deep wells located near the lake abstract a mixture of recently recharged water, deep aquifer waters and lake water with enriched isotopic compositions; and iv) the hydrogeochemistry and isotopic data reveal the presence of a hydraulic connection between the lake and deep wells. The findings of this study demonstrate that the catchment, the groundwater system, and Lake Babati are interlinked and, therefore, require the implementation of integrated water resources management to enhance sustainable development.
Hydrogeochemical Analysis of Water Quality Dynamics Under Anthropic Activities on the Southern Slopes of Mount Kilimanjaro, Tanzania
(Springer Nature, 2022-07-14) Said, Mateso; Komakech, Hans; Mjemah, Ibrahimu; Lufingo, Mesia; Munishi, Linus; Kumar, Sudhir
Water quality management requires consideration of surface water and groundwater dynamics. This study utilizes hydrogeochemical and isotopic techniques to understand anthropic influences on surface and groundwater resources in the Kikafu–Weruweru–Karanga (KWK) watershed southern slopes of Mount Kilimanjaro. The KWK watershed had two distinct characteristics, i.e., the upper region (above 1000 m.a.m.s.l) with surface water and few groundwater features and the lower part (below 1000 m.a.m.s.l) characterized by most groundwater sources and rivers. Water sampling and analysis were done between July and August 2019; multivariate statistical analysis aided the understanding of analytical findings. The results revealed NaHCO3 enrichment and Mixed CaNaHCO3 water type. The groundwater chemistry is chiefly controlled by aquifer lithology rather than anthropic activities. Stable isotopes show recharge from both regional and local rainfall as traced from the shallow wells. The levels of anthropic pollution indicators such as nitrate, chloride, and sulfate in deep wells are generally low in groundwater than in shallow wells. Anthropic activities such as irrigation, wastewater discharges and severe water abstraction confirmed significant contaminant agents at the dynamic levels. Next to geogenic releases, anthropic pollution as well is affecting groundwater quality in the aquifer. The current findings call for improved monitoring of the groundwater sources to track any changes in quality since there is a potential evolution to an undesirable state for domestic uses.