Environmental tracers to evaluate groundwater residence times and water quality risk in shallow unconfined aquifers in sub Saharan Africa

Banks, Eddie W.; Cook, Peter; Owor, Michael; Okullo, John Bosco Lamoris; Kebede, Seifu; Nedaw, Dessie; Mleta, Prince; Fallas, Helen; Gooddy, Daren C.; MacAllister, Donald John; Mkandawire, Theresa; Makuluni, Patrick; Shaba, C.; MacDonald, Alan

doi:10.1016/j.jhydrol.2020.125753

Cited by 24 publications

(7 citation statements)

References 87 publications

(103 reference statements)

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“…Oftentimes deep circulating groundwaters with longer residence time are more saline (Edmunds et al, 2003) than more shallow circulating short residence time groundwaters. Groundwater residence time control on groundwater salinity is evident in the volcanic aquifers of Eastern Africa (Ethiopia, Kenya, Tanzania) whereby shallow aquifers generally show low salinity compared to the deep circulating long residence time groundwaters (Kebede et al, 2005) (Banks et al, 2021).…”

Section: Rock Dissolutionmentioning

confidence: 99%

Assessing groundwater salinity across Africa

Gurmessa

MacAllister

White

et al. 2022

Science of The Total Environment

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Section: Rock Dissolutionmentioning

confidence: 99%

Assessing groundwater salinity across Africa

Gurmessa

MacAllister

White

et al. 2022

Science of The Total Environment

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“…Groundwater recharge was estimated to range between 3 and 50 mm/year over the period . Recently, MacDonald et al (2021 reported a long-term average groundwater recharge rate for Uganda of approximately 1 m/decade (≈100 mm/year), while Banks et al (2021) reported average estimated recharge rates using different techniques (CFCs, chloride mass balance, and water table fluctuation method) of 27-110 mm/year for sites in Uganda. Others (Mileham et al 2008;Nyenje and Batelaan 2009;Taylor and Howard 1996) found recharge rates in the order of 100-250 mm/year for specific study sites in Uganda.…”

Section: Hydrogeological Characterisation and Formation Of Springsmentioning

confidence: 99%

Hydrogeology of an urban weathered basement aquifer in Kampala, Uganda

et al. 2022

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Weathered basement aquifers are vital sources of drinking water in Africa. In order to better understand their role in the urban water balance, in a weathered basement aquifer in Kampala, Uganda, this study installed a transect of monitoring piezometers, carried out spring flow and high-frequency groundwater level monitoring, slug tests and hydrochemical analyses, including stable isotopes and groundwater residence time indicators. Findings showed a typical weathered basement aquifer with a 20–50-m thickness. Groundwater recharge was 3–50 mm/year, occurring during sustained rainfall. Recharge to a deep groundwater system within the saprock was slow and prolonged, while recharge to the springs on the valley slopes was quick and episodic, responding rapidly to precipitation. Springs discharged shallow groundwater, mixed with wastewater infiltrating from onsite sanitation practices and contributions from the deeper aquifer and were characterised by low flow rates (< 0.001 m3/s), low pH (<5), high nitrate values (61–190 mg/L as NO3), and residence times of <30 years. The deeper groundwater system occurred in the saprolite/saprock, had low transmissivity (< 1 × 10−5 m2/s), lower nitrate values (<20 mg/L as NO3), pH 6–6.5 and longer residence times (40–60 years). Confined groundwater conditions in the valleys were created by the presence of clay-rich alluvium and gave rise to artesian conditions where groundwater had lower nitrate concentrations. The findings provide new insights into weathered basement aquifers in the urban tropics and show that small-scale abstractions are more sustainable in the deeper groundwater system in the valleys, where confined conditions are present.

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“…This change in climate has negatively impacted the ecosystem, especially in lentic and lotic water bodies, which are important in giving better services for humans. As a result, efforts are needed to mitigate and tackle the consequences of destroying lotic (running water) such as rivers and lentic (standing water) such as lakes [1][2][3][4][5][6]. This task can be done by monitoring the freshwater ecosystems on a large scale or globally.…”

Section: Introductionmentioning

confidence: 99%

Water Quality Assessment of some Parameters of Dalmaj Marsh, Al-Diwaniya City, Iraq

Al-Jasimee

Hussein

2023

IOP Conf. Ser.: Earth Environ. Sci.

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The current study has investigated some parameters of Dalmaj Marsh, located in AL-Diwaniyah City, in Iraq, from the period of January 2022 to June 2022. In the field parameters such as electrical conductivity, salinity, TDS, pH, Turbidity, Temperature of air and water have been measured. Whereas, other parameters such as Biological oxygen demand BOD, Dissolved oxygen DO, total hardness, total alkalinity and chlorides have been measured at the laboratory. The results show that there has been a variation in parameters in all months of study, in the three studied sites. High salinity has been recorded and increased temperature in the studied sites. Also, high level of BOD has been recorded in Dalmaj Marsh that reflect deterioration of water. These findings provide crucial background data for further research.

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Environmental tracers to evaluate groundwater residence times and water quality risk in shallow unconfined aquifers in sub Saharan Africa

Cited by 24 publications

References 87 publications

Assessing groundwater salinity across Africa

Assessing groundwater salinity across Africa

Hydrogeology of an urban weathered basement aquifer in Kampala, Uganda

Water Quality Assessment of some Parameters of Dalmaj Marsh, Al-Diwaniya City, Iraq

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