Resilience of rural groundwater supplies during drought in Ethiopia

As a result of climate change, sub-Saharan Africa, is expected to experience more frequent and extreme droughts, contributing to greater water insecurity. Droughts affect the reliability, quantity and quality of water available, potentially undermining recent gains in drinking water access and making it difficult to extend services. Ethiopia, in particular, is highly vulnerable to drought. Since 1965, Ethiopia has experienced 15 severe droughts affecting more than 65 million people and causing serious economic damage. Most recently, in 2015 and 2016, Ethiopia suffered a harsh drought, linked to El Nino, which forced more than 10 million people to rely on emergency aid due to crop and water supply failures. During the 2015-16 drought significant effort was made to monitor and understand the performance and use of rural water points. Drawing on two recently published studies we demonstrate that with adequate monitoring and maintenance rural groundwater points can deliver a consistent and safe water supply during drought. The first study monitored a total of 5196 water points (hand-pumps, motorized boreholes, springs, open-sources) and the success of a maintenance programme, every week for 12 weeks in early 2016. Enumerators used questionnaires on mobile phones to gather quantitative and qualitative data from those responsible for water points. The second study involved monitoring 51 groundwater points (hand-pumps, springs, hand-dug wells) over an 18 month period. Water sources were equipped with water level loggers and water was tested monthly for Thermo-tolerant Coliforms (TTCs). All sources were put under considerable strain during drought. Most demand was placed on motorised boreholes in lowland areas. Increases in functionality for motorised boreholes, as a result of the maintenance programme, lagged behind those of hand-pumped boreholes. More complex technologies have longer downtimes due to a lack of appropriate and/or accessible maintenance skills. Real time-monitoring and effective information flow helped facilitate responsive and proactive maintenance of infrastructure, and ensured demand was spread across a larger infrastructure portfolio reducing pressure on individual sources during the drought. Water level monitoring showed that shallow boreholes equipped with handpumps recovered quickly from daily abstraction. Recovery rates of hand-dug-wells and springs was longer. All sources were contaminated during the rains marking drought cessation but boreholes were least affected. We conclude that 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 maintenance, increases rural water supply resilience to drought and climate change

Regional groundwater flow system characterization of volcanic aquifers in upper Awash using multiple approaches, central Ethiopia

Characterization of the groundwater flow systems is important for sustainable water resource management decision-making. We have used vertical profiles of electrical conductivity (EC) and water temperature taken at 2 m intervals during drilling of 109 boreholes, and samples for stable isotope analysis (δ18O, δ2H) taken from 47 boreholes to characterize groundwater recharge, flow and discharge in the Upper Awash sub-basin, central Ethiopia. 222Rn measurements and piezometric evidence were used to complement results from the EC and stable isotopes. The converging evidence shows that groundwater in the study area is characterized by a mix of two different groundwater flow systems: i) the deep groundwater systems are connected to the regional groundwater flow originating from the highlands, outside the surface water basin, ii) the shallow groundwater systems get recharge from local rains. The local recharge zones are located in highly urbanized and industrialized zones posing risk to recharge reduction and pollution. Therefore, attention should be given to protect groundwater resources from contamination and increase groundwater resilience to climate change. This dataset was collected under research conducted within the REACH programme - reachwater.uk - between 14/04/2021 and 31/03/2022

Functionality and resilience of hand-pumped boreholes in sub-Saharan Africa

In sub-Saharan Africa as many as 184 million people rely on hand-pumps. Thus, hand-pumps are, and will remain, a crucial water source in a changing climate, although as many as one in three are non-functional at any time. Drawing on the results of three studies we demonstrate that hand-pumps are resilient and safe, and we examine the physical factors that determine hand-pump functionality. In the first study we analysed the performance of 5196 water points (hand-pumps, motorized boreholes, springs, open-sources) and the success of a proactive maintenance programme during the 2015-16 drought in Ethiopia. Water sources were visited every week for 12 weeks to gather data on access and functionality. The second study, again in Ethiopia, involved monitoring 51 groundwater points (hand-pumps, springs, hand-dug wells) over an 18-month period in 2016. Water sources were equipped with water level loggers and were tested monthly for thermo-tolerant coliforms. All sources were put under considerable strain during the drought. Most demand was placed on motorised boreholes in lowland areas. However, increases in functionality of motorised boreholes, as a result of the maintenance programme, lagged behind those of hand-pumps. Functionality was low for both sources at the on-set of the drought (65% and 75% respectively). Motorised boreholes had longer downtimes due to a lack of appropriate and/or accessible maintenance skills. Water level monitoring showed that hand-pumped boreholes recovered most quickly from daily abstractions. All sources were contaminated with thermo-tolerant coliforms during the rains marking drought cessation but hand-pumped boreholes were least affected. Our results show that hand-pumped boreholes are resilient and less prone to contamination than springs and hand-dug wells. However, like the other sources we studied, hand-pumps had low levels of functionality at the onset of the drought. To better understand the factors affecting functionality we systematically dismantled 150 hand-pumped boreholes in Ethiopia, Uganda and Malawi in 2017. We conducted detailed inspections of hand-pump components and borehole design. Water levels were measured and a pumping test was conducted to measure aquifer yield (transmissivity). In each country specific contextual factors influence functionality. In Ethiopia deep water levels (>60 m) strongly influence functionality. Many hand-pumps operate beyond lift limits (45 m). Aquifer yield is an order of magnitude larger for fully functional hand-pumps than partially functional hand-pumps in Ethiopia. In Uganda many hand-pumps are installed in aquifers with transmissivities close to the minimum required to sustain a hand-pump (c.1 m2/d). The use of galvanized steel components, along with corrosive groundwater, results in high rates of corrosion in Uganda. In all three countries hydrogeology, borehole design and pump condition interact to determine functionality outcomes. Our results reinforce the importance of appropriate borehole siting and design, on-going operation and maintenance and use of appropriate and good quality materials. When supported by responsive and proactive maintenance hand-pumped boreholes, which are less prone to contamination than other shallow groundwater sources, are a resilient water source in a changing climate and are capable of providing water continuously during drought

Three-dimensional hydrostratigraphical modelling supporting the evaluation of fluoride enrichment in groundwater: Lakes basin (Central Ethiopia)

Study region The Lakes Basin is located in the Main Ethiopian Rift. It covers the northern part of the rift valley basin, the Upper Awash River basin, and some sub-basins from the Omo River basin. Due to the presence of high fluoride (F−) content, natural contamination of groundwater has long been recognized as a water-related health issue in the area. Study focus A multidisciplinary research effort, including geological, hydrogeological, hydro-chemical, and geophysical investigations, was adopted to understand the 3D hydrogeological conceptual model and to evaluate F− enrichment in groundwater. New hydrological insights for the region The 3D hydrogeological conceptual model shows a complex hydrogeological environment and a clear hydraulic interconnection between different aquifers. The geological setting has deeply influenced the geometry of the aquifers, recharge and discharge areas, and F− enrichment in groundwater. Two hydrogeological units, namely sedimentary and volcanic multi-aquifers, were identified. The analyses of groundwater circulation, flow paths, and distribution of F- concentrations in each aquifer were conducted. In groundwater, the concentration of fluoride varies from 0.1 to 68.9 mg L−1; in surface water, it ranges from 0.6 to 244.2 mg L−1. Fluoride concentration of 62 % of the water samples analyzed exceeded the 1.5 mg L−1 WHO threshold for fluoride concentration in drinking water. The proposed methodological approach has been demonstrated to be a powerful tool that could be applied in other similar areas