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The Mediterranean basin is highly sensitive to the likely impacts of man-made climate change, including temperature rises of up to 3.5 °C and up to 10 % lower rainfall, potentially leading to a 50 % drop in renewable water resources by the end of the 21st century.
Fresh groundwater resources are also at risk due to intensive use of fertilisers in agriculture, industrial pollution, and exploitation of coastal aquifers leading to seawater intrusion. Meanwhile, surface water is being lost as run-off into the sea, and wastewater seen as a nuisance rather than a resource; if properly treated and stored it can be reclaimed for use, especially during the drier seasons.
Lack of confidence in the ability to safely reclaim water — a process called managed aquifer recharge (MAR) — has held back this option until now. The EU-funded MARSOL project has shown not only that MAR is a viable approach to addressing long-term predicted water shortages, but also that attitudes can be changed thanks to awareness-raising and training.
Save and store
The basic idea behind the system is simple: collect water when there is too much of it and store it for dry times in aquifers. This subsurface storage even works beneath deserts. MAR can also be used to combat sea water intrusion in coastal areas and give pre-treated waste water a final clean-up, says project coordinator Christoph Schüth of Darmstadt Technical University in Germany.
“We demonstrated that MAR is a sound, safe, cost-effective and sustainable strategy that can be used with great confidence in the framework of integrated water resource management,” he says.Wider take-up of MARSOL’s tools is the next crucial step, and there are already positive signs of interest in the project’s demonstration sites, says Schüth.
A joint Israeli-German project is exploring aquifer recharge as a sustainable storage solution for desalinated sea water. And Maltese partners are developing a MAR master plan for the island, as well as a scaled-up version of the project demo for the Malta South aquifer system.
At the Rio Seco infiltration basin site in Portugal, aquifer recharge activities are continuing with the aim of improving local groundwater quality. And community awareness activities and workshops are ongoing at the Spanish Arenales site, especially aimed at farmers who depend on irrigation.
Sound, safe and cost-effective
The project took a holistic approach to addressing the many questions raised by MAR, including the risks, water quality and technical feasibility, but also administrative and legal aspects, such as those covered in the EU Water Framework Directive (WFD).
Demonstrations at eight sites in Greece, Portugal, Spain, Malta, Italy and Israel explored different scenarios, such as ‘infiltrating’ desalinated sea water, surface water, or treated waste water into aquifers, and how water can be stored underground using different techniques.
Innovative monitoring systems, open-software decision-support systems, computer models, technical guidelines, benchmarking criteria for site selection and operation, risk assessment schemes, and proposals for MAR-tailored regulatory frameworks were developed and tested at the project’s demonstration sites.
Altogether, MARSOL’s tools and technologies proved effective in real-world conditions. The team optimised a cost-effective, high-resolution system — called time-domain reflectometry (TDR) — for monitoring water content in the unsaturated zone. It also developed a wireless sensor network for real-time field data transmission and storage.
Other tools includ a web-based platform with a user-friendly interface for data analyses and decision-making, and a concept for benchmarking and evaluating different MAR schemes in terms of performance and results. Water-quality guidelines and contaminant criteria were set up, and a theoretical framework for risk assessment at MAR sites developed.
A regulatory framework was also put in place to help MAR practitioners interpret the WFD requirements. This is a key element, the team concluded after meetings with stakeholders. While the solutions are technically feasible and can be cost-effectively implemented with the right commitment, in many cases the missing element was a regulatory approach to MAR based on a solid scientific basis, as called for by the WFD’s River Management Plans. For example in Italy, recharge aquifers have been allowed since 2013, but the legal framework has lagged behind.
Workshops, public meetings, consultations and networking activities proved essential for the SMEs involved in the project to gain and share experience. These exchanges have inspired a number of follow-up initiatives which are being developed into concrete proposals, especially in the direction of MAR training for young scientists, professionals and other stakeholders in the water sector.
The global water-quality monitoring market alone is valued at USD 2.95 billion (€ 2.78 billion) and expected to reach USD 4.69 billion (€ 4.42 billion) by 2025, according to analysts who predict exponential growth in Europe because of increased awareness of water pollution and contamination issues.
“Climate change and population growth will increase demand for food, energy and other natural resources, putting additional stress on diminishing water resources unless something is done,” says Schüth. “MARSOL’s solutions are not only cost-effective, they are ready to meet a growing market – and urgent need – for clean, sustainable water sources.”