Crystalline Bedrock aquifers underlie about 40% of Sub-Saharan Africa and can generally sustain low-intensity abstraction. However, pumping rates and dependency is increasing in many areas, particularly for cities like Addis Ababa, Dakar, Nairobi and Dodoma. Projected growth in population and water demand for agriculture, plus the effects of climate change, mean that it is essential to develop a better understanding of the sustainable yields from these types of aquifers.
The study focuses on five groundwater abstraction boreholes, 3 in Uganda, 2 in Tanzania.
Long term groundwater records are only available for one of the boreholes and it shows that recharge happens more when the rainfall is more intense, which is often associated with periodic El Niño Southern Oscillation (ENSO) events.
Chemical analysis of the water was used to determine the residence times of the groundwater (how long the water has been in the aquifer since it fell as rain). Overall, that most pumped water comes from modern recharge (within the last 10-60 years), so while abstractions are not mining pre-modern groundwater, there may be a component of older water that is coming out.
Groundwater abstraction appears to be supported by recharge from across multiple years, rather than just the most recent wet season.
The investigation of the five sites shows that long term, high intensity groundwater abstraction is possible from East African weathered crystalline basement aquifers, but the sustainability is constrained, in part, by the high inter-annual variability in recharge. Therefore operation of such pumping stations needs to include sustained monitoring of groundwater levels, pumping rates and rainfall as a minimum.
“Adaptive governance” has a number of core principles:
The need to live with change and uncertainty
To foster adaptive capacity (i.e. being able to anticipate and respond to change and uncertainty)
To understand human and natural systems as interconnected
To consider resilience as the central desirable attribute, e
One of two case studies focuses on a non-UPGro project, called SWAUM (2011-2016), in the Great Ruaha River catchment in Tanzania (which, by coincidence is one of the GroFutures observatories)
Concerns about the catchment arose in the 1990s and a number of donor-funded projects tried to improve the natural/water resource management of the catchment.
An evaluation of the SWAUM project had strengthened coordination both vertically and horizontally through hierarchies at different political levels.
Limited improvements in land management had taken place but despite the greater awareness, debate and agreement, local people continued to cultivate river banks and river beds to the detriment of the river flows – and despite a deliberate attempt to include marginalised people, they did not get significant representation from pastoralists. This may be in part due to a dominant narrative from other, more powerful, stakeholders that they are to blame for resource depletion.
Cleaver and Whaley conclude that the following three elements are inextricably bound together:
Process: institutions that are designed for adaptive governance (such as knowledge sharing platforms, resource management arrangements) may only work and endure where they serve other socially valued processes and are embedded in accepted forms of behaviour and practices.
Power: allocation or resources or dominance of particular narratives about cause-and-effect is driven by visible, hidden and invisible uses of power by individuals, social groups and organisations. This is often why designed interventions for adaptive governance often deliver less than expected.
Meaning: There different worldviews on cause and effect in the human and natural worlds and involve multiple processes that will likely affect adaptive governance arrangements.
Many cities in Sub-Saharan Africa, and other low and middle income countries, are growing fast. Expansion of water supply systems to meet that growing demand is challenging, particularly in the context of climate change and competing water uses, such as agriculture.
Scenario planning, with geographical information systems, is an essential tool to help government bodies and utilities plan investments in urban and peri-urban water supply infrastructure and services, but examples in developing countries remain rare and have generally been rural.
The case study, Kisumu, is a city in Western Kenya near the shores of Lake Victoria. The Kisumu Water and Sewerage Company (KIWASCO) has responsibility across the city.
12 key informants with particular insights into the water and sanitation sector, social and economic planning and human population dynamics were identified and included in two sessions: (1) Background information and future trajectories of population growth; (2) computer software called “International Futures” was used to explore different population scenarios, which formed the basis of discussions on water and sanitation planning for the city in three groups.
Through the participatory planning in separate groups it was possible to draw out where areas of consensus and uncertainty about how the city, and its demand for water and sanitation will change. One area of common agreement was that groundwater and on-site sanitation will remain an important part of the mix until at least 2030, which implies and longer-term need for interventions like household filters, chlorine dispensers at well heads, education or land tenure reforms to enable sewerage installation.
Future research should focus on a broader range of scenarios than just extending current trends in population change, for example: ethnic conflict, social fragmentation, and rapid, Chinese-led infrastructure development.
Related UPGro work on urban groundwater or groundwater for urban areas:
Globally, 25% of people lack access to water that is free from microbial contamination, in some countries the proportion is much higher. This has major health implications, particularly for children.
Monitoring water quality for disease-causing organisms is difficult, and the common method is take water samples to a lab to measure Coli bacteria. Although largely successful, it is an expensive in terms of time and materials, and cannot be relied on for some kinds of biological water quality risks – particularly in groundwater where the absence of E.Coli does not guarantee biological safety of the water.
Tryptophan-like fluorescence (TLF) is a relatively new way of rapidly measuring biological water quality in the field, without needing expensive and time-consuming lab equipment and consumables. It is better suited to groundwater than surface water monitoring.
Key Points: –
This is the first groundwater study to compare TLF with E. Coli specifically.
Tryptophan-like fluorescence (TLF) can complement E. coli as a risk indicator, but it is not proposed as a replacement.
Both TLF and coli distinguish low/intermediate, high and very high risk sources.
TLF has negligible variability due to the method, unlike bacteriological analyses.
TLF is useful for pre-screening, monitoring and demonstrating risk in groundwater.
Fieldwork for this research was done in rural Kwale Country, Kenya
Next steps include:
focus on how TLF relates to pathogens and health, rather than just focusing on the coincidence with E.Coli.
better understanding of TLF in different groundwater conditions
better computer software of processing and presenting TLF data
assess the usefulness of TLF in communicating water risks to groundwater users.
Groundwater Recharge – the set of processes that govern how rainwater seeps through soils and rocks to replenish aquifers – is not well understood across much of Africa. It is important to understand because it is central to determine the sustainable use of groundwater resources;
The authors analyse three rare sets of long-term (19-25 years) groundwater-level observations from three different, but common, geological settings in Benin;
The year-to-year changes in groundwater storage correlate well with rainfall patterns, but there were big differences the relate to the type of geology:
In the shallow, sand aquifer as much as 40% of the rainfall becomes groundwater
In the deeper sandstone and weathered crystalline rocks, a much lower proportion of rainfall becomes groundwater recharge (13% and 4% respectively)
Recharge was found to occur on a seasonal basis; however on a daily basis the groundwater fluctuations are best explained with a threshold of 5-15 mm per day – meaning that only more intense rainfall events lead to recharge.
These results are consistent with the growing body of evidence that, in Sub-Saharan Africa, intensification of rainfall associated with climate change may increase groundwater recharge.
Because the groundwater recharge is so strongly influenced by geology, it is essential for water resource planning that good geological maps are available and used, and that investment is made into long-term groundwater monitoring of strategic aquifers.
GRACE (Gravity Recovery and Climate Experiment) satellite can be used to estimate changes in water storage on time resolution of 1 month and a spatial resolution of about 450 x 450 km.
GRACE can be used to estimate groundwater storage changes where it is the dominant water mass. It is therefore useful in many areas of Sub-Saharan Africa where there are relatively few direct groundwater level measurements.
The paper focuses on the major sedimentary aquifers basins, where the majority of Africa’s groundwater resources are to be found. Away from these basins, groundwater storage is 1-2 orders of magnitude less.
There is no evidence of continuous long-term declining trends of Total Water Storage (mostly groundwater) in any of the major sedimentary aquifers, which indicates that none are stressed by current abstraction rates – howeverit is important to stress that local scale depletion may be occurring but is beyond the resolution of GRACE to detect.
There are also some interesting findings in regard to the combination of GRACE and Land Surface Modelling and how well (or not) they represent groundwater recharge processes in the different basins.
Read the full paper here:
Bonsor, H.C.; Shamsudduha, M.; Marchant, B.P.; MacDonald, A.M.; Taylor, R.G. Seasonal and Decadal Groundwater Changes in African Sedimentary Aquifers Estimated Using GRACE Products and LSMs. Remote Sens.2018, 10, 904. http://www.mdpi.com/2072-4292/10/6/904
New educational resource developed by the Gro for GooD team launched for secondary schools in Kwale County, Kenya to increase understanding of groundwater and water quality
Outreach to schools teaches girls and boys about water science and management
Event held on 17th March to celebrate the collaboration between the UPGro team, the schools, local government and private sector partners.
“You have a very great opportunity through your water clubs, guided by your teachers who are here and who can support you. We should take this as a very special opportunity for all of us”
The UPGro Gro for GooD project has been delivering a programme of engagement to teach young people in Kwale County about water science and management. Water Clubs at 3 secondary schools have been participating in field trips, practical activities, experiments and conducting their own group research projects. This outreach work aims to develop students’ research and communication skills and showcase career options in the water sector.
In the run up to World Water Day 2018, the Gro for GooD project was delighted to welcome Madam Bridget Wambua, Director of Education for Kwale County, Kenya, to provide opening remarks (extract above) at a special event to celebrate the success of the Schools Water Clubs supported by the project over the last year. As the event got going, students listened with great interest to the keynote speech by Prof. Dan Olago from the University of Nairobi, and then took to the stage themselves for a series of presentations about club activities including water quality testing of school waterpoints, the installation and use of rain-gauges on school grounds, and field trips to the Base Titanium mine to see how the mine manages and recycles water in its operation.
Other students presented their own mini-research projects into topics such as water conservation in agriculture and strategies for keeping water safe to drink, and one group gave an excellent explanation of artesian wells based on an email exchange with Gro for GooD hydrogeologist Mike Lane.
Students also brought practical demonstrations and posters to show in the teabreak, including a solar still demonstration from a group of students who had just heard that they are through the local round and have been invited to show their improved solar still design at Kenya’s National Science Fair for schools.
Madame Wambua and Professor Dan Olago then presented the schools, water clubs and club patrons with certificates of appreciation for their hard work and dedication to water-related environmental education, and 2 laptops were given to each club. The laptops were provided by the UK charity IT Schools Africa and preloaded with water-related environmental education resources collated by the Gro for GooD team.
Students also received print copies of a newly published Water Module Student Resource which was developed by the Gro for GooD research team with input from students and teachers at the schools. Mr Joseph Kimtai, teacher and club patron at Kingwede Girls Secondary School, said,
“I find this module of activities about water so helpful to the students – it complements what we are teaching in class. It also encourages critical thinking and solving problems related to the environment which is in line with one of the competencies of the incoming competency-based curriculum for Kenyan schools.”
The resource has been published under a Creative Commons licence so that other educational programmes in Kenya can make use of the content.
Co-author of the Water Module, Nancy Gladstone, said:
“It has been a privilege to work with secondary school students in Kwale County and help to meet their really encouraging thirst for knowledge about water. Education has a vital role in achieving the Sustainable Development Goal for water and we are sure that many of these students will put their learning to good use at school and as they go on to jobs and further education.
“The Water Module event also provided us with an opportunity to thank the teachers, headteachers and local partner organisations such as Base Titanium and Rural Focus Ltd. who have all been critical to the success of the clubs this past year, and to contribute to discussions about building the water module into ongoing education programmes in Kwale County, both formal and informal, so as to reach more students and further enhance learning.”
Groundwater is essential for economic growth and can contribute to human development if resources are used sustainably to benefit the poorest in society. The Gro for GooD (Groundwater Risk Management for Growth and Development) project is striving to help government and groundwater users find a management approach that balances human health, economic growth, and resource sustainability demands and benefits everyone. Project partners are University of Oxford, University of Nairobi, Jomo Kenyatta University of Agriculture and Technology, Universitat Politècnica de Catalunya, Rural Focus Ltd., Kwale County Government, the Government of Kenya’s Water Resources Authority, Base Titanium and KISCOL.
More information about Gro for GooD, which is funded by UK research councils and the Department for International Development, can be found here.