Borehole sustainability in rural Africa: an analysis of routine field data

Handpump-equipped boreholes are one of the most common water supply technologies adopted in rural Africa, but often demonstrate low levels of sustainability. In addition to operational problems with the pump, the borehole itself may cease to provide adequate quantities of safe drinking water only a short time after construction. This can have a significant negative impact on poor rural communities, particularly in the dry season when alternative water sources are scarce. A study of 302 boreholes in Ghana aimed to investigate rapid-onset borehole failure in relation to field data typically available following drilling and development. The study showed that the likelihood of borehole failure increased by a factor of six when drilling occurred during the wet season, and discovered a strong correlation between monthly precipitation and respective failure rates for boreholes drilled in each month. The potential for borehole failure also increased significantly when the initial yield was below the guideline value of 10 l/min. There was no indication, however, that a higher guideline value would be a cost-effective measure to reduce failure rates.