Contribution of physical factors to handpump borehole functionality in Africa.

Handpumps are the main water supply for rural communities across sub-Saharan Africa. However, studies show that >25 % of handpumps are non-functional at any time. We present results from a systematic field study of handpump borehole functionality. The study was designed to investigate the contribution of physical factors to functionality outcomes, including; hydrogeology, borehole configuration, and handpump components. To achieve this, we deconstructed and examined 145 handpump boreholes in Ethiopia, Uganda and Malawi. Pumping tests showed that 19 % of boreholes were located in aquifers with transmissivity below the minimum required to sustain a handpump. Water levels, measured during the dry season, had a complex relationship with borehole configuration and transmissivity. The handpump cylinder was <10 m below the water table at 38 % of sites, which increases the risk of the handpump running dry during intensive use and/or in areas of low transmissivity. The water column was <20 m at 23 % of sites and screens were <10 m long at 29 % of sites and often sub-optimally positioned in the borehole. Borehole depth had no clear relationship with functionality. Using multinomial regression and four functionality categories (functional; unreliable; low yield; unreliable and low yield) as dependant variables, we found that transmissivity is a significant risk factor for the classification of handpump boreholes as low yield. The configuration of the borehole (e.g. cylinder position, screen/casing configuration and water column) is a statistically significant risk factor for the classification of handpump boreholes as unreliable. Handpump components were in poor overall condition but rising main pipes were a particular problem with 53 % of galvanised pipes corroded and 82 % of uPVC pipes damaged, with implications for handpump performance. Our study highlights the importance of; understanding aquifer properties, investing in borehole siting, construction (including supervision) and commissioning, and improving the quality of components and maintenance of handpumps.

Comparative performance of rural water supplies during drought.

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 min, increasing to 30-60 mins, for hand-pumped boreholes. Boreholes accessing deep (>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.