Evidence for extreme variations in the permeability of laterite from a detailed analysis of well behaviour in Nigeria

Bonsor, H.C.; MacDonald, Alan; Davies, J.

doi:10.1002/hyp.9871

Cited by 31 publications

(30 citation statements)

References 41 publications

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“…Very rapid horizontal pathways exist in the shallow tropical soil zone, which may be laterally extensive, in some cases providing transmissivities in excess of 300 m 2 /day (Bonsor et al 2014). Rapid vertical pathways also exist due to the presence of natural macropores, e.g.…”

Section: Urban Populationmentioning

confidence: 99%

“…Separation distances of 10-50 m were commonly recommended; however, there was no detailed consideration of higher-risk settings such as those posed by tropical soils, which cover a considerable part of Africa, or karstic settings which require considerably greater separation distances (e.g. Bonsor et al 2014).…”

Section: Separation Between Sources Of Pollution and Groundwater Abstmentioning

confidence: 99%

“…Given the potentially important role rapid horizontal (and vertical) pathways play in tropical soils overlying basement aquifers (e.g. Bonsor et al 2014) on the migration of contaminants in the subsurface, and the widespread occurrence of this aquifer type across SSA, this is a key topic that warrants further investigation. Although not the focus of this paper, it is clear that socioeconomic aspects need to be better integrated with physical hydrogeology if urban groundwater security research is to be effective and relevant.…”

Section: Conclusion and Research Prioritiesmentioning

confidence: 99%

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Urban groundwater quality in sub-Saharan Africa: current status and implications for water security and public health

et al. 2017

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Groundwater resources are important sources of drinking water in Africa, and they are hugely important in sustaining urban livelihoods and supporting a diverse range of commercial and agricultural activities. Groundwater has an important role in improving health in sub-Saharan Africa (SSA). An estimated 250 million people (40% of the total) live in urban centres across SSA. SSA has experienced a rapid expansion in urban populations since the 1950s, with increased population densities as well as expanding geographical coverage. Estimates suggest that the urban population in SSA will double between 2000 and 2030. The quality status of shallow urban groundwater resources is often very poor due to inadequate waste management and source protection, and poses a significant health risk to users, while deeper borehole sources often provide an important source of good quality drinking water. Given the growth in future demand from this finite resource, as well as potential changes in future climate in this region, a detailed understanding of both water quantity and quality is required to use this resource sustainably. This paper provides a comprehensive assessment of the water quality status, both microbial and chemical, of urban groundwater in SSA across a range of hydrogeological terrains and different groundwater point types. Lower storage basement terrains, which underlie a significant proportion of urban centres in SSA, are particularly vulnerable to contamination. The relationship between mean nitrate concentration and intrinsic aquifer pollution risk is assessed for urban centres across SSA. Current knowledge gaps are identified and future research needs highlighted.

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Section: Urban Populationmentioning

confidence: 99%

Section: Separation Between Sources Of Pollution and Groundwater Abstmentioning

confidence: 99%

Section: Conclusion and Research Prioritiesmentioning

confidence: 99%

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Urban groundwater quality in sub-Saharan Africa: current status and implications for water security and public health

et al. 2017

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“…Lohani et al (2011) {13] investigated the aquifers of Jatni area and reported that GWT of the area lies in fractures and sedimentary sandstone in succession within laterite and old alluvium of Holocene epoch. Bonsor et al, (2014) [14] reported that the quantity and quality of GW are influenced by permeability properties of Laterites which partition the surface runoff and interflow. Mishra et.…”

Section: +4mentioning

confidence: 99%

Geo-Hydro-Chemistry of Latosol Mineralogy: SMD and Western Catchment of Chilika Lagoon, India.

Mishra¹,

Patnaik²,

Mishra³

2018

IJAR

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“…Oju/Obi is a remote part of SE Nigeria and experiences severe water shortages during the annual dry season, despite a high average annual rainfall of c. 1600 mm (Davies & MacDonald 1999). The area has been subject to extensive groundwater investigations in an attempt to improve the stubbornly high rates of guinea worm infection and low water supply coverage (MacDonald et al 2001(MacDonald et al , 2005(MacDonald et al , 2008Bonsor et al 2014). Oju/Obi is situated within the lower section of the Benue Trough, a major elongated geological rift structure infilled with fine-grained, low-permeability Cretaceous sediments (Ofoegbu 1985).…”

Section: Study Areamentioning

confidence: 99%

Fractures in shale: the significance of igneous intrusions for groundwater flow

MacDonald

Davies

2018

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Research in Cretaceous shales from West Africa has demonstrated that significant permeability can develop within shales at shallow depths (<100 m), equivalent to a permeability of >1 m day−1. Much of the variation in permeability is related to the degree of burial metamorphism, with shales that have been altered and that approach the anchizone having the highest permeability and those that are largely unaltered (early diagenetic zone) having the lowest permeability. However, further research targeting largely unaltered shales dominated by smectite clay has shown that the presence of small igneous intrusions can radically alter the hydrogeology. Twenty-four exploratory boreholes were drilled into smectite-dominated shale and nine of these boreholes were targeted to small dolerite intrusions within the shale. The dolerite was intensely fractured at the intrusion edge, with significant zeolite growth along the fracture surfaces. The permeability in the fractured dolerite was the highest measured in any shale borehole, with transmissivities of up to 60 m2 day−1 measured from pumping tests. Fracturing was less where dolerite was intruded into sandstones, however, and the measured transmissivity was lower (<0.5 m2 day−1). We postulate that the low permeability and high water content of the shale enabled high pressures to develop during intrusion, facilitating the development of fractures along the intrusion contact zone.

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Evidence for extreme variations in the permeability of laterite from a detailed analysis of well behaviour in Nigeria

Cited by 31 publications

References 41 publications

Urban groundwater quality in sub-Saharan Africa: current status and implications for water security and public health

Urban groundwater quality in sub-Saharan Africa: current status and implications for water security and public health

Geo-Hydro-Chemistry of Latosol Mineralogy: SMD and Western Catchment of Chilika Lagoon, India.

Fractures in shale: the significance of igneous intrusions for groundwater flow

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