Urban groundwater quality in Africa : benefits and challenges

Most urban centres in Africa rely on groundwater, in Southern Africa it is estimated that at least 36% of the population relies on groundwater, this number is much larger for many other settlements in Africa. Urban water supplies are reliant on local groundwater sources to supply 25% of water use, from both private and public/municipal sources. Groundwater is important even in areas where groundwater abstraction is limited by low productivity groundwater stores such as those found in hard-rock settings (e.g. granites). Urban centres are a focus for a wide range of human activities past and present that can alter groundwater quality with potential impacts on subsequent groundwater uses. Once contaminated, groundwater can be challenging to clean up. Despite these challenges, groundwater is often of better quality compared to surface water alternatives in urban settings. Groundwater is generally well protected from surface contamination: as water percolates through the soil and deeper rock some contaminants (e.g. bacteria) may be removed. In contrast to surface water pollution, groundwater quality changes are often gradual, allowing scope for the problem to be assessed and interventions and adaptations to be planned and undertaken if recognised early. Even when groundwater is contaminated (e.g. by bacteria or organic contaminants) these are often detected at low concentrations. Compared to surface waters treatment, costs are often lower and simpler treatment solutions are possible due to the reduced pollution loads and fluctuations in groundwaters. Access to groundwater is widely dispersed compared to alternative sources (lakes, rivers and piped supplies). This offers a clear potential to expand groundwater use in many towns and cities to enhance water security (e.g. via public water supply, piped systems with standpipes, self-supply such as private wells and in some cases tankered or sachet groundwater)

Urban Groundwater in Africa: a dialogue for resilient towns and cities

Just half of the urban population in Africa has access to safely-managed water supplies. With urban populations forecast to double in the next 30 years securing access to sufficient quantities of water of suitable quality will be one of the greatest challenges we face. The challenge is all the greater when we take into account the added pressure of climate change and of economic growth. Our groundwater is one means to address this challenge. Not only is it a readily accessible source of supply for many towns and cities it has the advantage of being less susceptible to climate change than many sources of surface waters. However, as an accessible source of water there are many pressures on our groundwater reserves. Alongside municipal water providers, domestic households often access groundwater directly for drinking and non-drinking purposes. Similarly, small-scale and larger commercial vendors may use it as a source from which to supply urban consumers. Other commercial actors include both small firms and large companies, who use groundwater as an input to their production processes. Groundwater can also provide an essential contribution to urban and peri-urban agriculture. Furthermore, groundwater sustains many of our rivers and dependant ecosystems. Used wisely, our groundwater can provide a key input promoting the health and welfare of our urban populations and their surrounding environment. However, as a resource that is hidden from view there is a real risk that users may abstract too much water, or that the resource becomes contaminated. As we start to exploit our groundwater resources more fully, it is essential that all parties have a good understanding of this ‘invisible’ resource. Decisions are being made on a daily basis about how our groundwater is used, or on activities that affect our groundwater. These decisions are taken by many parties and may not always be to the benefit of our groundwater resources. Maintaining our groundwater requires a dialogue between parties. This publication helps promote dialogue. It provides an accessible summary for those who are not technical experts. It highlights the potential that groundwater offers and reminds us why the management and protection of groundwater resources is essential for the long-term water security and resilience of urban areas across Africa. It is not a definitive guide though, but a starting point for discussion and conversation. It is for this reason that we call it a ‘Dialogue’. The African Ministers’ Council on Water (AMCOW) is committed to the effective management of our continent’s water resources and the provision of water supply services. Our remit promotes co-operation to achieve wider economic, social and environmental goals. Managing groundwater is a key contributor to urban water security. This ‘Dialogue’ provides a first step in that process, by identifying three golden rules and 13 policy principles. We are pleased with the support for this dialogue process already shown by many parties and welcome the opportunity this presents. With this ‘Dialogue’, I invite others to contribute to a dialogue on managing our urban groundwater. We welcome responses, challenges, new ideas and examples of good practice. Together we can help secure our continent’s groundwater resources to promote the resilience of our towns and cities