As rural African communities experience more frequent and extreme droughts, it is increasingly important that water supplies are climate resilient. Using a unique temporal dataset we explore rural water supply (n = 5196) performance during the 2015–16 drought in Ethiopia. Mean functionality ranged from 60% for motorised boreholes to 75% for hand-pumped boreholes. Real-time monitoring and responsive operation and maintenance led to rapid increases in functionality of hand-pumped and, to a lesser extent, motorised boreholes. Increased demand was placed on motorised boreholes in lowland areas as springs, hand-dug-wells and open sources failed. Most users travelled >1 h to access motorised boreholes but 30 m) groundwater performed best during the drought. Prioritising access to groundwater via multiple improved sources and a portfolio of technologies, such as hand-pumped and motorised boreholes, supported by responsive and proactive operation and maintenance, increases rural water supply resilience.
Two years of self‐potential (SP) measurements were made in a monitoring borehole in the coastal UK Chalk aquifer. The borehole SP data showed a persistent gradient with depth, and temporal variations with a tidal power spectrum consistent with ocean tides. No gradient with depth was observed at a second coastal monitoring borehole ca. 1 km further inland, and no gradient or tidal power spectrum were observed at an inland site ca. 80 km from the coast. Numerical modeling suggests that the SP gradient recorded in the coastal monitoring borehole is dominated by the exclusion‐diffusion potential, which arises from the concentration gradient across a saline front in close proximity to, but not intersecting, the base of the borehole. No such saline front is present at the two other monitoring sites. Modeling further suggests that the ocean tidal SP response in the borehole, measured prior to breakthrough of saline water, is dominated by the exclusion‐diffusion potential across the saline front, and that the SP fluctuations are due to the tidal movement of the remote front. The electrokinetic potential, caused by changes in hydraulic head across the tide, is one order of magnitude too small to explain the observed SP data. The results suggest that in coastal aquifers, the exclusion‐diffusion potential plays a dominant role in borehole SP when a saline front is nearby. The SP gradient with depth indicates the close proximity of the saline front to the borehole and changes in SP at the borehole reflect changes in the location of the saline front. Thus, SP monitoring can be used to facilitate more proactive management of abstraction and saline intrusion in coastal aquifers.
This study examines the performance of the policy of community management for rural groundwater supply in Africa. Across the continent, policies that promote community management have dominated the rural water supply sector for decades. As a result, hundreds of thousands of village-level committees have been formed to manage community boreholes equipped with handpumps. With a significant proportion of these handpumps non-functional at any one time, increasing effort is targeted toward understanding the interacting social and physical determinants of this ‘hidden crisis’. We conducted a survey of community management arrangements across six hundred sites in rural Ethiopia, Malawi, and Uganda, examining the extent to which management capacity is related to borehole functionality whilst accounting for a range of contextual variables. The capacity of water management arrangements (WMAs) was assessed according to four dimensions: finance system; affordable maintenance and repair; decision making, rules, and leadership; and external support. The survey reveals that 73.3% of WMAs have medium or high capacity. However, we found no strong relationship between the capacity of the WMA and the functionality of the borehole. Of the four management dimensions, affordable maintenance and repair was the best predictor of borehole functionality. However, the capacity of this dimension was seen to be the lowest overall, with 61.9% of sites weak or non-existent. Our results provide very limited support for the policy of community management, and we suggest that evidence alone has not accounted for its persistence over decades. After a short historical analysis, we conclude that explanation for the endurance of this model can be found in the nexus between evidence, ideology, and policy. We argue that it is this same nexus that will likely ensure the popularity of community management for some time to come, despite new ideas and evidence to the contrary.
Monitoring of self‐potentials (SPs) in the Chalk of England has shown that a consistent electrical potential gradient exists within a coastal groundwater borehole previously affected by seawater intrusion (SI) and that this gradient is absent in boreholes further inland. Furthermore, a small but characteristic reduction in this gradient was observed several days prior to SI occurring. We present results from a combined hydrodynamic and electrodynamic model, which matches the observed phenomena for the first time and sheds light on the source mechanisms for the spatial and temporal distribution of SP. The model predictions are highly sensitive to the relative contribution of electrochemical exclusion and diffusion potentials, the exclusion efficiency, in different rock strata. Geoelectric heterogeneity, largely due to marls and hardgrounds with a relatively high exclusion efficiency, was the key factor in controlling the magnitude of the modeled SP gradient ahead of the saline front and its evolution prior to breakthrough. The model results suggest that, where sufficient geoelectric heterogeneity exists, borehole SP may be used as an early warning mechanism for SI.