Your search found 6 records
1 Knappett, P. S. K.; Mailloux, B. J.; Choudhury, I.; Khan, M. R.; Michael, H. A.; Barua, S.; Mondal, D. R.; Steckler, M. S.; Akhter, S. H.; Ahmed, K. M.; Bostick, B.; Harvey, C. F.; Shamsudduha, M.; Shuai, P.; Mihajlov, I.; Mozumder, R.; van Geen, A. 2016. Vulnerability of low-arsenic aquifers to municipal pumping in Bangladesh. Journal of Hydrology, 539:674-686. [doi: https://doi.org/10.1016/j.jhydrol.2016.05.035]
Groundwater ; Aquifers ; Recharge ; Arsenic ; Contamination ; Drinking water ; Pumping ; Water levels ; Hydraulics ; Hydrogeology ; Models ; Urban areas ; Communities ; Wells ; Rivers ; Deltas / Bangladesh / Dhaka / Araihazar
(Location: IWMI HQ Call no: e-copy only Record No: H047769)
(4.05 MB)
Sandy aquifers deposited >12,000 years ago, some as shallow as 30 m, have provided a reliable supply of low-arsenic (As) drinking water in rural Bangladesh. This study concerns the potential risk of contaminating these aquifers in areas surrounding the city of Dhaka where hydraulic heads in aquifers >150 m deep have dropped by 70 m in a few decades due to municipal pumping. Water levels measured continuously from 2012 to 2014 in 12 deep (>150 m), 3 intermediate (90–150 m) and 6 shallow (<90 m) community wells, 1 shallow private well, and 1 river piezometer show that the resulting drawdown cone extends 15–35 km east of Dhaka. Water levels in 4 low-As community wells within the 62–147 m depth range closest to Dhaka were inaccessible by suction for up to a third of the year. Lateral hydraulic gradients in the deep aquifer system ranged from 1.7 104 to 3.7 104 indicating flow towards Dhaka throughout 2012–2014. Vertical recharge on the edge of the drawdown cone was estimated at 0.21 ± 0.06 m/yr. The data suggest that continued municipal pumping in Dhaka could eventually contaminate some relatively shallow community wells.
2 Kolusu, S. R.; Shamsudduha, M.; Todd, M. C.; Taylor, R. G.; Seddon, D.; Kashaigili, J. J.; Ebrahim, Girma Y.; Cuthbert, M. O.; Sorensen, J. P. R.; Villholth, Karen G.; MacDonald, A. M.; MacLeod, D. A. 2019. The El Nino event of 2015-2016: climate anomalies and their impact on groundwater resources in East and Southern Africa. Hydrology and Earth System Sciences, 23: 1751-1762. [doi: https://doi.org/10.5194/hess-23-1751-2019]
El Nino ; Groundwater management ; Water resources ; Water storage ; Climate change ; Rainfall ; Drought ; Water balance ; Water levels ; Surface water ; Precipitation ; Evapotranspiration ; Satellite imagery ; Satellite observation / East Africa / SouthernAfrica / Limpopo Basin
(Location: IWMI HQ Call no: e-copy only Record No: H049164)
https://www.hydrol-earth-syst-sci.net/23/1751/2019/hess-23-1751-2019.pdf
https://vlibrary.iwmi.org/pdf/H049164.pdf
https://vlibrary.iwmi.org/pdf/H049164.pdf
(2.80 MB)
The impact of climate variability on groundwater storage has received limited attention despite widespread dependence on groundwater as a resource for drinking water, agriculture and industry. Here, we assess the climate anomalies that occurred over Southern Africa (SA) and East Africa, south of the Equator (EASE), during the major El Niño event of 2015–2016, and their associated impacts on groundwater storage, across scales, through analysis of in situ groundwater piezometry and Gravity Recovery and Climate Experiment (GRACE) satellite data. At the continental scale, the El Niño of 2015–2016 was associated with a pronounced dipole of opposing rainfall anomalies over EASE and Southern Africa, north–south of ~12° S, a characteristic pattern of the El Niño–Southern Oscillation (ENSO). Over Southern Africa the most intense drought event in the historical record occurred, based on an analysis of the cross-scale areal intensity of surface water balance anomalies (as represented by the standardised precipitation evapotranspiration index – SPEI), with an estimated return period of at least 200 years and a best estimate of 260 years. Climate risks are changing, and we estimate that anthropogenic warming only (ignoring changes to other climate variables, e.g. precipitation) has approximately doubled the risk of such an extreme SPEI drought event. These surface water balance deficits suppressed groundwater recharge, leading to a substantial groundwater storage decline indicated by both GRACE satellite and piezometric data in the Limpopo basin. Conversely, over EASE during the 2015–2016 El Niño event, anomalously wet conditions were observed with an estimated return period of ~10 years, likely moderated by the absence of a strongly positive Indian Ocean zonal mode phase. The strong but not extreme rainy season increased groundwater storage, as shown by satellite GRACE data and rising groundwater levels observed at a site in central Tanzania. We note substantial uncertainties in separating groundwater from total water storage in GRACE data and show that consistency between GRACE and piezometric estimates of groundwater storage is apparent when spatial averaging scales are comparable. These results have implications for sustainable and climate-resilient groundwater resource management, including the potential for adaptive strategies, such as managed aquifer recharge during episodic recharge events.
3 Cuthbert, M. O.; Taylor, R. G.; Favreau, G.; Todd, M. C.; Shamsudduha, M.; Villholth, Karen G.; MacDonald, A. M.; Scanlon, B. R.; Kotchoni, D. O. V.; Vouillamoz, J.-M.; Lawson, F. M. A.; Adjomayi, P. A.; Kashaigili, J.; Seddon, D.; Sorensen, J. P. R.; Ebrahim, Girma Yimer; Owor, M.; Nyenje, P. M.; Nazoumou, Y.; Goni, I.; Ousmane, B. I.; Sibanda, T.; Ascott, M. J.; Macdonald, D. M. J.; Agyekum, W.; Koussoube, Y.; Wanke, H.; Kim, H.; Wada, Y.; Lo, M.-H.; Oki, T.; Kukuric, N. 2019. Observed controls on resilience of groundwater to climate variability in sub-Saharan Africa. Nature, 572(7768):230-234. [doi: https://doi.org/10.1038/s41586-019-1441-7]
Groundwater recharge ; Climate change ; Resilience ; Groundwater table ; Observation ; Precipitation ; Hydrology ; Hydrography ; Models ; Arid zones ; Rain / Africa South of Sahara / Benin / Uganda / United Republic of Tanzania / Zimbabwe / South Africa / Namibia / Niger / Ghana / Burkina Faso
(Location: IWMI HQ Call no: e-copy only Record No: H049316)
https://www.nature.com/articles/s41586-019-1441-7.epdf?author_access_token=UgizrPwmrGzlbL33bjbvQdRgN0jAjWel9jnR3ZoTv0M3C122Ih9FQbr0PbeOlDAX9EZlbSwXsaUcJ-Vq-8EelgPfWJQTdVE-2_3g7yypNR4C-qTOMe7Ux1weufjBdaT9SyaKgJjfKYgJ2fqsjIRLng%3D%3D
https://vlibrary.iwmi.org/pdf/H049316.pdf
https://vlibrary.iwmi.org/pdf/H049316.pdf
(7.21 MB)
Groundwater in sub-Saharan Africa supports livelihoods and poverty alleviation1,2 , maintains vital ecosystems, and strongly influences terrestrial water and energy budgets3 . Yet the hydrological processes that govern groundwater recharge and sustainability—and their sensitivity to climatic variability—are poorly constrained4,5 . Given the absence of firm observational constraints, it remains to be seen whether model-based projections of decreased water resources in dry parts of the region4 are justified. Here we show, through analysis of multidecadal groundwater hydrographs across sub-Saharan Africa, that levels of aridity dictate the predominant recharge processes, whereas local hydrogeology influences the type and sensitivity of precipitation–recharge relationships. Recharge in some humid locations varies by as little as five per cent (by coefficient of variation) across a wide range of annual precipitation values. Other regions, by contrast, show roughly linear precipitation–recharge relationships, with precipitation thresholds (of roughly ten millimetres or less per day) governing the initiation of recharge. These thresholds tend to rise as aridity increases, and recharge in drylands is more episodic and increasingly dominated by focused recharge through losses from ephemeral overland flows. Extreme annual recharge is commonly associated with intense rainfall and flooding events, themselves often driven by large-scale climate controls. Intense precipitation, even during years of lower overall precipitation, produces some of the largest years of recharge in some dry subtropical locations. Our results therefore challenge the ‘high certainty’ consensus regarding decreasing water resources4 in such regions of sub-Saharan Africa. The potential resilience of groundwater to climate variability in many areas that is revealed by these precipitation–recharge relationships is essential for informing reliable predictions of climate-change impacts and adaptation strategies.
4 Panda, D. K.; Ambast, S. K.; Shamsudduha, M.. 2021. Groundwater depletion in northern India: impacts of the sub-regional anthropogenic land-use, socio-politics and changing climate. Hydrological Processes, 35(2):e14003. [doi: https://doi.org/10.1002/hyp.14003]
Groundwater depletion ; Anthropogenic factors ; Land use change ; Anthropogenic climate change ; Social aspects ; Political aspects ; Water storage ; Aquifers ; Groundwater table ; Extreme weather events ; Drought ; Rain ; Temperature ; Food security ; Policies / India / Indo-Gangetic Plain / Punjab / Haryana / Delhi / Rajasthan / Uttar Pradesh / Bihar / West Bengal
(Location: IWMI HQ Call no: e-copy only Record No: H050230)
(2.79 MB)
Understanding the key drivers behind intensive use of groundwater resources and subsequent depletion in northern India is important for future food security of India. Although spatio-temporal changes of groundwater storage (GWS) and its depletion in northern India are mapped using the NASA's GRACE (Gravity Recovery and Climate Experiment) records, the sub-regional diverse socio-political and environmental factors contributing to the variability in groundwater withdrawals and renewals are not well documented. Here, we provide new evidence on changes in GWS at different spatial scales using both observations and satellite-based measurements applying both parametric and non-parametric statistical analyses. The substantial loss of GWS has occurred since the beginning of the 21st century, and the decline in GWS is associated with some record-breaking dry and hot climate events. We present how certain state-based policy decisions, such as supplying free electricity for irrigation, prompted farmers to extract groundwater unsustainably and thus led to widespread GWS deletion, which has been also accelerated by frequent dryness and rising temperatures. In the hotspot of Punjab, Haryana and Delhi of northern India, the extracted groundwater during 1985–2013 is equivalent to a metre-high layer if spread uniformly across its geographical domain. We find that the groundwater storage loss in northern India has increased rapidly from 17 km3 to 189 km3 between the pre-2002 and 2002–2013 periods. This loss in northern India is, therefore, an excellent example of rapid surface greening and sub-surface drying—a result of an interplay of socio-political and environmental factors. As groundwater continues to be treated as a common natural resource and no clear definition exists to guide policymaking, this study also illustrates how the administrative district level approach can solve the widespread problem of depletion.
5 Sorensen, J. P. R.; Davies, J.; Ebrahim, Girma Y.; Lindle, J.; Marchant, B. P.; Ascott, M. J.; Bloomfield, J. P.; Cuthbert, M. O.; Holland, M.; Jensen, K. H.; Shamsudduha, M.; Villholth, Karen G.; MacDonald, A. M.; Taylor, R. G. 2021. The influence of groundwater abstraction on interpreting climate controls and extreme recharge events from well hydrographs in semi-arid South Africa. Hydrogeology Journal, 29(8):2773-2787. [doi: https://doi.org/10.1007/s10040-021-02391-3]
Groundwater extraction ; Groundwater recharge ; Well hydrographs ; Semiarid climate ; Catchment areas ; Groundwater table ; Rain ; River flow ; Stream flow ; Extreme weather events ; El Nino-Southern Oscillation ; Hydrogeology ; Boreholes ; Spatial distribution ; Land use / South Africa / Limpopo / Mogalakwena Catchment / Sand River Catchment
(Location: IWMI HQ Call no: e-copy only Record No: H050671)
https://link.springer.com/content/pdf/10.1007/s10040-021-02391-3.pdf
https://vlibrary.iwmi.org/pdf/H050671.pdf
https://vlibrary.iwmi.org/pdf/H050671.pdf
(6.26 MB) (6.26 MB)
There is a scarcity of long-term groundwater hydrographs from sub-Saharan Africa to investigate groundwater sustainability, processes and controls. This paper presents an analysis of 21 hydrographs from semi-arid South Africa. Hydrographs from 1980 to 2000 were converted to standardised groundwater level indices and rationalised into four types (C1–C4) using hierarchical cluster analysis. Mean hydrographs for each type were cross-correlated with standardised precipitation and streamflow indices. Relationships with the El Nino– Southern Oscillation (ENSO) were also investigated. The four hydrograph types show a transition of autocorrelation over increasing timescales and increasingly subdued responses to rainfall. Type C1 strongly relates to rainfall, responding in most years, whereas C4 notably responds to only a single extreme event in 2000 and has limited relationship with rainfall. Types C2, C3 and C4 have stronger statistical relationships with standardised streamflow than standardised rainfall. C3 and C4 changes are significantly (p < 0.05) correlated to the mean wet season ENSO anomaly, indicating a tendency for substantial or minimal recharge to occur during extreme negative and positive ENSO years, respectively. The range of different hydrograph types, sometimes within only a few kilometres of each other, appears to be a result of abstraction interference and cannot be confidently attributed to variations in climate or hydrogeological setting. It is possible that high groundwater abstraction near C3/C4 sites masks frequent small-scale recharge events observed at C1/C2 sites, resulting in extreme events associated with negative ENSO years being more visible in the time series.
6 Bellwood-Howard, I.; Thompson, J.; Shamsudduha, M.; Taylor, R. G.; Mosha, D. B.; Gebrezgi, Gebrehaweria; Tarimo, A. K. P. R.; Kashaigili, J. J.; Nazoumou, Y.; Tiekoura, O. 2022. A multicriteria analysis of groundwater development pathways in three river basins in Sub-Saharan Africa. Environmental Science and Policy, 138:26-43. [doi: https://doi.org/10.1016/j.envsci.2022.09.010]
Groundwater management ; River basins ; Water policies ; Water governance ; Water availability ; Large-scale farming ; Small-scale farming ; Water use ; Water users ; Multiple use ; Water quality ; Environmental sustainability ; Groundwater extraction ; Stakeholders ; Communities ; Modelling ; Uncertainty / Africa South of Sahara / Ethiopia / Niger / United Republic of Tanzania / Great Ruaha Sub-Catchment / Iullemmeden Basin / Awash Basin
(Location: IWMI HQ Call no: e-copy only Record No: H051559)
https://www.sciencedirect.com/science/article/pii/S146290112200288X/pdfft?md5=4e23255036c0e457072d97d30d062c6e&pid=1-s2.0-S146290112200288X-main.pdf
https://vlibrary.iwmi.org/pdf/H051559.pdf
https://vlibrary.iwmi.org/pdf/H051559.pdf
(10.10 MB) (10.1 MB)
Reliance on groundwater in Sub-Saharan Africa is growing and expected to rise as surface water resource variability increases under climate change. Major questions remain about how groundwater will be used, and who informs these decisions. We represent different visions of groundwater use by ‘pathways’: politically and environmentally embedded socio-technological regimes for governing and managing groundwater systems. We presented policy actors (9 sets), development and research stakeholders (4 sets), and water users (6 sets) in three river basins in Ethiopia, Niger and Tanzania with information on the social and environmental impacts of six ‘Groundwater Development Pathways’, before gathering their opinions on each, through Multicriteria Mapping (MCM). Participants preferred pathways of low-intensity use, incorporating multiple agricultural, pastoral and domestic purposes, to high-intensity single-use pathways. Water availability and environmental sustainability, including water quality, were central concerns. Participants recognised that all groundwater uses potentially impinge upon one another affecting both the quantity and quality of abstracted water. Across participant groups there was ambiguity about what the most important water use was; each expressed demands for more detailed, certain modelling data. Water users preferred community or municipal-scale management regimes, perceiving that water quality was more likely to be safeguarded by institutions at these levels, whereas policy and development actors preferred individual-scale management, viewed as more efficient in terms of operation and maintenance. We conclude that MCM, combined with more detailed modelling, can provide an effective framework for policy actors to understand other stakeholders’ perspectives on groundwater development futures, enabling equitable, inclusive decision-making and governance.
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