The invisible Blue Gold
It is invisible and has often been perceived as a mystery. Up until the seventeenth century, from Aristotle to Descartes, the belief prevailed that groundwater flows from the sea via mysterious channels to the mountains, where it emerges from springs [R1].
Today, we know that this is not true. But are you also aware that groundwater is the most abundant source of freshwater on earth, accounting for about 99 % of liquid freshwater [R2]? This vital resource not only supplies almost half of the world's drinking water [R3], it plays also an important role in the provision of several services to human activities, including flood mitigation, seawater intrusion control, sustaining aquatic ecosystems and being a critical storage element for climate-change adaptation.
Groundwater Resources at Risk
Yet despite its importance, groundwater is still poorly understood, undervalued [R4 ] and not well enough managed [R3].
As human activities and climate change increase, so does the dependence and pressure on groundwater resources, which are being pumped at an alarming and unsustainable rate. As a result, overexploitation of aquifers in many places leads to subsidence of the earth's surface, drying up of springs, decline in river flow, increased vulnerability to pollution and seawater intrusion. Coastal areas in particular are increasingly suffering from inadequate drinking water supplies and declining quality of agricultural land due to progressive soil salinisation, a trend that is expected to intensify due to the effects of climate change.
Managed Aquifer Recharge as a Solution
If managed intelligently and sustainably, such as through managed aquifer recharge (MAR), groundwater has significant untapped potential to enhance water security, especially in times of climate change [R4].
However, despite the multiple benefits of MAR (including financial and environmental), its contribution to water security at the global level is still limited. The reasons for this include the lack of public acceptance of MAR, open questions about its impacts and missing capacities and resources for optimal operational management. These barriers can be addressed with detailed real-time data on geohydrological processes, which help to monitor reliably and to predict and mitigate risks associated with groundwater recharge.
It is important to note that MAR is not a one-size-fits-all solution. The applicability and benefits of MAR systems depend on various technical and socio-economic aspects. MAR must be seen as an integrated solution that requires a sound governance of multiple water resources and conflicting interests.
To help reduce risks associated with MAR, adelphi in the frame of the SMART-Control project trained and engaged MAR stakeholders in the use of an innovative web-based, real-time monitoring and control system (RMCS)—including an INOWAS Decision Support System (DSS) —at pilot sites in Cyprus and Brazil. Additionally, adelphi explored application opportunities of the RMCS at potential replication sites with core stakeholders helping encourage greater uptake of MAR in the years ahead.
Main outcomes of adelphi’s activities aimed at reducing risks associated with managed aquifer recharge:
- Feedback from training participants showed a high level of interest in MAR solutions and related monitoring and control tools. Training and stakeholder engagement proved to be an important pillar in developing solutions to reduce barriers to MAR implementation.
- A needs assessment among MAR stakeholders at the pilot sites in Brazil and Cyprus prevailed a high demand for the following technical training topics: (a) real-time monitoring with online sensors including data visualisation and interpretation, (b) groundwater model-based predictions and running of different scenarios, (c) microbial risk assessment and (d) cost-benefit analysis for MAR systems.
- The first three topics are well covered by tailored web-based tools offered by the open source modelling platform INOWAS DSS, which is so far limited to analysing the technical and environmental feasibility and benefits of MAR. Even though the evaluation of costs and benefits for MAR are getting more and more into focus [R5], existing CBA tools are limited to desktop-based Excel spreadsheets, often difficult to handle. Recently, the team submitted a project proposal including the integration of a CBA tool to the INOWAS DSS to reduce application barriers through the web-based implementation and provide decision makers guidance on the most economic and sustainable MAR option.
- Interactive discussions and feedback sessions revealed the following main risks that MAR stakeholders at the pilot sites consider to be most challenging for MAR operations and essential to address (many responses refer to the reuse of water through MAR, as done in Cyprus):
- In Brazil, stakeholders stressed the importance of adequate legislation to establish MAR systems. For a smooth implementation and operation of MAR, it requires stronger governance, e.g. through the introduction of a licensing system, technical guidelines, and standards.
- Authorities suggested that upcoming projects should go beyond a demonstration project and address governance, funding and incentives for MAR to maximise impacts.
adelphi’s contribution has helped to raise awareness and build capacities for sustainable use of groundwater resources. Our aim in this way was not only to strip groundwater of some of its mystical charm, but rather to strengthen the recognition of the full potential of groundwater management in climate adaptation and water security in the years to come.
- Gun, J.v.d. and Margat, J. 2013. Groundwater around the World: A Geographic Synopsis. ISBN: 978-0-203-77214-0
- United Nations 2022. The United Nations World Water Development Report 2022: Groundwater: Making the invisible visible. UNESCO, Paris. URL: https://unesdoc.unesco.org/ark:/48223/pf0000380721
- International Groundwater Resources Assessment Center 2018. Groundwater overview: Making the invisible visible. URL: https://www.un-igrac.org/sites/default/files/resources/files/Groundwater...
- Villholth, K.G. and Sticklor, R. 2022. Exploring the untapped potential of managed aquifer recharge, Blog entry, URL: https://www.iwmi.cgiar.org/
- Zheng, Y.; Ross, A.; Villholth, K.G.; Dillon, P. (Eds.) 2021. Managing aquifer recharge: A showcase for resilience and sustainability. Paris, France: United Nations Educational, Scientific and Cultural Organization (UNESCO). 379p. ISBN: 978-92-3-100488-9