Browsing by Author "Nyangoka, Justus"

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    Insights from electrical resistivity tomography on the hydrogeological interaction between sand dams and the weathered basement aquifer
    (Elsevier, 2024-11-01) Ritchie, Hannah; Holman, Ian; Nyangoka, Justus; Bauman, Paul; Parker, Alison
    Sand dams, composed of recent alluvial aquifers behind concrete dam walls, are a water management technique in drylands. However, their level of hydraulic connectivity with their surrounding weathered basement aquifer is debated. This study aims to constrain this hydrogeological uncertainty in order to better understand their ability to meet water needs and improve dryland water security. The study is the first to use 2D geophysics (Electrical Resistivity Tomography) to provide evidence of seepage from sand dams at three mature and three newly built sites. A generally greater hydraulic connectivity was found between sand dams and their surrounding aquifer than has been assumed in some previous studies, with sites providing at least some local recharge rather than existing as isolated storage structures. This improved understanding is beneficial for both site selection and the performance of sand dams and can help ensure that maximum benefits are derived from the construction of a sand dam depending on its intended purpose.
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    The multiple uses of water derived from managed aquifer recharge systems in Kenya and India
    (IWA, 2022-01-19) Parker, Alison H.; Nyangoka, Justus; Rodrigues, Inês; Yadav, B.; Le Corre Pidou, Kristell; Campo Moreno, Pablo; Quinn, Ruth
    ‘Multiple-use services’ (MUS) takes into account the fact that households use water for both domestic and for productive uses. This paper is the first to determine how managed aquifer recharge (MAR) systems are a form of MUS. Two cases were studied in India and in Kenya. In the Kenyan case, sand dams are the form of MAR, and in India check dams and infiltration ponds of various scales are used. Through observations, interviews, and water quality data, it is possible to describe how the communities access the water from these infrastructures in multiple ways for different uses, according to their water needs and the characteristics of the different access points. MAR involves harvesting rainwater and retaining run-off water into the dry season thus increasing the amount of available water and enabling diversification of water uses. It should therefore be considered as an option by water managers aiming to develop water resources meeting both the domestic and productive needs of communities.