Permeability of the weathered bedrock aquifers in Uganda: evidence from a large pumping test dataset and its implications for rural water supply

Weathered crystalline-rock aquifers underlie around 40% of sub-Saharan Africa providing water supplies for half of its rural population; they are also prevalent across the tropics. The hydrogeology of these aquifers is complex and better understanding of the controls to aquifer transmissivity, alongside accurate borehole siting and appropriate design, is pivotal to the long-term performance and sustainability of water services in many countries. This study examines a substantial new dataset (n = 655) of aquifer transmissivity values across Uganda derived from previously unanalyzed pumping-test data. These data provide important new insights: weathered crystalline-rock aquifers are distinguished by pervasively low transmissivities (median <2 m2/d) in comparison to other areas in the tropics; highest transmissivities are observed in boreholes <50 m deep, implying that drilling deeper boreholes does not typically improve supply success or sustainability in Uganda; and increased groundwater abstraction through the use of higher-yielding pump technologies will prove challenging in most areas of Uganda and limit their use for piped water supplies. This study highlights the scientific value of data held in drillers’ records, which remain unanalyzed in many countries but may provide useful insight and understanding of aquifer characteristics

To what extent does community management ensure good functionality of groundwater supplies in rural Africa?

Within rural Africa, communal boreholes fitted with handpumps (HPBs) are likely to remain the main source of improved water supplies for decades to come. Understanding how the performance of these supplies can be improved will be central to achieving improved water security. The functionality of community HPBs relies on a range of elements which include not only groundwater resource availability, correct siting and construction of the borehole and handpump mechanism, but also equitable and enabling management arrangements. Since the 1980s – the first UN ‘Water Decade’ – Community Based Management (CBM) has been the policy prescription par excellence for operationalising participatory development in the rural water supply sector. The cornerstone of the CBM model is the creation of a local water point committee or similar community organisation, which is charged with the operation and maintenance of the borehole. Despite its popularity and endurance, there is a relative lack of evidence on how the management capacity of communities relates to the functionality of their boreholes, and a growing recognition among development practitioners and academics that CBM of rural water supply has struggled to deliver on many of its promises. Here we present the findings from a survey of six hundred communities across rural Ethiopia, Uganda and Malawi to examine the extent to which community water management capacity is related to borehole functionality. The capacity of water management arrangements (WMA) was assessed according to four dimensions: finance system; affordable maintenance and repair; decision making, rules, and leadership; and external support. HPB performance was assessed using on a nuanced definition of borehole functionality, which captures different tiers of functionality from a simple binary ‘yes/no’ working, to capturing the level of functionality performance and reliability. The findings reveal that whilst over two thirds of WMA are of medium to high capacity in communities, there is no strong relationship between the WMA capacity 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 lowest overall, with nearly two thirds of sites having weak or non-existent capacity in this respect. These findings provide evidence to support the growing claim that, in many instances, CBM by itself does not ensure improved functionality performance

Environmental tracers to evaluate groundwater residence times and water quality risk in shallow unconfined aquifers in sub Saharan Africa

In sub-Saharan Africa, shallow aquifer systems are relied on as the main safe and secure water resource available to rural communities. Information on the sustainability and vulnerability of groundwater abstraction is becoming increasingly important as groundwater development increases. As part of the UpGro Consortium Project- Hidden Crisis, 150 hand pumped boreholes (HPBs), ranging between 15 and 101 m depth were investigated to examine the resilience of aquifer systems in the Ethiopian Highlands, and the crystalline basement rocks of Uganda and Malawi. Environmental tracers (chlorofluorocarbons (CFCs), SF6, chloride and the stable isotopes of water), water quality indicators (nitrate and E. coli), and groundwater-level time series data were used to estimate groundwater residence time and recharge at a regional scale (100–10,000 km2) and investigate the risks to water quality and water supply over different timeframes, and geological and climatic environments. Average estimated recharge rates using three different techniques (CFCs, chloride mass balance, water table fluctuation method) were between 30 and 330, 27–110 and 30–170 mm y−1, for sites in Ethiopia, Uganda and Malawi, respectively. These estimates of recharge suggests abstraction from dispersed low-yielding HPBs is sustainable. Comparison of stable isotopes in rainfall and groundwater indicates that there is little evaporation prior to recharge, and recharge events are biased to months with greater rainfall and more intense rainfall events There was a weak correlation between nitrate and CFCs within all three countries, and no correlation between E. coli and CFCs within Ethiopia or Malawi. The presence of E. coli at a large proportion of the sites (Ethiopia = 38%, Uganda = 65% and Malawi = 47%) suggests rapid transit of contaminated surface water into the borehole and its presence in groundwater that has CFC-12 concentrations less than 75 pg kg−1 indicates mixing of very young water with water >40 years old. The rapid transit pathways are most likely associated with damaged HPB headworks and poor construction. In several monitored HPBs, daily drawdown due to pumping, drew the groundwater levels close to the base of the HPB, indicating that these HPBs were located in parts of the aquifer with low permeability, or were poorly designed, offering limited capacity for increased demand. Improved HPB siting and construction, coupled with groundwater level monitoring are required to capitalise on the more resilient groundwater within the shallow aquifers and safeguard adequate and good quality water supply for rural communities

New city planning policy processes – creating a prescient awareness of groundwater for future places and people

Groundwater is a crucial resource for the resilient and sustainable development of nearly all cities in some way – whether as a key component resource in public water supply, to integrated flood risk management, potential renewable shallow geothermal heat, or roles in contamination pathways and ground stability. The roles and interactions of the resource with urban development are manifold and cross-cutting, but often are not addressed in a comprehensive way. New urban planning approaches are necessary not only for cities to achieve key outcomes of improved health, low carbon growth, and environmental quality, but also to meet rates of urbanisation and mitigate increasing climatic variability. Current trajectories estimate the world’s urban population in 2050 will be equivalent of the world’s total population in 2004. Both the number and size of cities worldwide is growing, with highest rates of urban growth in Africa and Asia. City Development Plans and National Planning policy are the key spatial strategies which will deliver our future cities around the world, in a wide variety of landscapes. It is essential these policies are developed with increased awareness of the role, and various interactions, groundwater can play in the urban context, alongside other environmental facets. This will require increased professional collaboration in city planning; and the realization of more effective evidence processes throughout city development processes. Both of these are vital to achieving more effective and pertinent cascades of information, and a prescient awareness of how groundwater can be best harnessed and managed to deliver future cities. This presentation provides a review of some of the roles and interactions groundwater has across range different urban geographies; and, evaluates some of the different knowledge exchange approaches used in Europe to develop earlier cross-sectoral awareness of groundwater in city planning. The presentation examines key emerging lessons learnt so far; and the changing relationships and knowledge exchange required to support these

Hidden Crisis Project, Survey 1 dataset: detailed functionality assessments of hand pump boreholes in Ethiopia, Uganda and Malawi

This dataset provides the field data collected in 2016 to assess: the functionality and performance of 600 handpumped borehole supplies (HPBs) across the three countries, Ethiopia, Malawi and Uganda, and also the capacity of the community water management arrangements. The individual HPBs surveyed in the dataset were selected by a two or three stage randomised sampling approach. The UPGro Hidden Crisis project (2015-20) was an international research project aimed at developing a robust evidence base and understanding of the complex and multi-faceted causes which underlie the current high failure rates of many new groundwater supplies in Africa. The project was jointly funded by: DFID, NERC and ESRC as part of the UPGro programme (Unlocking the Potential of Groundwater for the Poor). The project carried out the research work in three countries - Ethiopia, Malawi and Uganda – to examine functionality and performance of groundwater supplies in a range of hydrogeological, climatic and social, institutional and governance environments in East Africa. The work focused specifically on examining the functionality of HPBs – these being the main form of improved community water supply across rural Africa. The Survey 1 dataset, is major dataset developed by the project. This data set is available under Open Government Licence, subject to the following acknowledgement accompanying any reproduced materials: "Contains data supplied by permission of the Natural Environment Research Council [YEAR]"

Hidden Crisis Project, Survey 2 dataset: hand pump borehole diagnostic tests in Ethiopia, Uganda and Malawi

This dataset provides a detailed physical science dataset to the groundwater resource and engineering properties of 150 handpumped borehole supplies (HPBs) across Ethiopia, Malawi and Uganda, surveyed in 2017 as part of the UPGro Hidden Crisis project. The dataset includes measurements of aquifer resource potential, groundwater quality, downhole construction and condition of handpump components, and borehole construction. Detailed social science data were also collected as part of the second survey phases of the Hidden Crisis project. However, these data are reported as a separate (associated) dataset to the physical science Survey 2 dataset – and are available from Economic and Social Research Council (ESRC) UK Data Service (UKDS). The UPGro Hidden Crisis project (2015-20) was an international research project aimed at developing a robust evidence base and understanding of the complex and multi-faceted causes which underlie the current high failure rates of many new groundwater supplies in Africa. The project was jointly funded by: DFID, NERC and ESRC as part of the UPGro programme (Unlocking the Potential of Groundwater for the Poor). The project carried out the research work in three countries - Ethiopia, Malawi and Uganda – to examine functionality and performance of groundwater supplies in a range of hydrogeological, climatic and social, institutional and governance environments in East Africa. The work focused specifically on examining the functionality of HPBs – these being the main form of improved community water supply across rural Africa. The Survey 2 dataset, is major dataset developed by the project. This data set is available under Open Government Licence, subject to the following acknowledgement accompanying any reproduced materials: "Contains data supplied by permission of the Natural Environment Research Council [YEAR]"

Taking the long view: 120 years of groundwater accumulation and depletion in the world's most heavily exploited aquifer - the Indo Gangetic Basin

Observed groundwater level decline in parts of Northern India and Pakistan have raised questions about the sustainability of current irrigation practices in the Indo Gangetic Plain. Recent studies using insitu groundwater level measurements and geochemical methods show a complex pattern of impacts from abstraction and recharge with a high degree of spatial variability. The areas of most concern for the aquifer are within the states of Punjab and Haryana in India and Punjab Province in Pakistan. Here groundwater levels can be 20 – 50 m below ground level and are falling at rates of 0.5 – 1 ma-1. However, the recent depletion is set within a much longer history of groundwater level variations spanning the last 150 years. Here we have brought together approximately 50 long term hydrographs from northern India and Pakistan which give an unparalleled account of the accumulation of groundwater within the basin due to the widespread construction of canal systems in the Indus and Ganges in the 19th and early 20th centuries; the subsequent stabilization of groundwater levels attributed to state sponsored drilling and pumping to mitigate water-logging and salinization; and then the rise of private boreholes for irrigation in the 1980s and 90s. During the 1990s groundwater abstraction began to locally exceed surface water use for irrigation, and water levels began to fall rapidly is some areas. Currently, leakage from the irrigation canals is a vital source of recharge and any plans to improve efficiency of surface water irrigation will impact further on groundwater. Taking the long view of the patterns of past groundwater accumulation and depletion can therefore help to unravel the current complex pattern of groundwater level variation and water quality

Borehole and transmissivity dataset, Uganda

This dataset comprises 655 borehole records and previously unanalysed pumping tests from across Uganda that were compiled from historical borehole records held within 9 district water offices. The dataset is a compilation of historical borehole records held within nine district water offices across Uganda. These data originated from numerous drilling campaigns undertaken by private contractors in each district to site and construct hand-pump borehole community water supplies between 2000 to 2018. In total over 1000 paper borehole records were initially collated and reviewed. This work was carried out over several months visiting the district water offices. Following a quality assurance procedure 655 records were transcribed to create a digital dataset. Each borehole record in the dataset contains a series of metadata alongside the pumping test data (e.g. pump depth, static water level, pumping rate and duration) including locational information (e.g. coordinates, water strike, borehole depth, borehole lithologies). The dataset is delivered as a series georeferenced site information within an MS Excel spreadsheet file. This data set is available under Open Government Licence, subject to the following acknowledgement accompanying any reproduced materials: "Contains data supplied by permission of the Natural Environment Research Council [YEAR]"