Malta Intelligent Energy Management Agency

The limestone islands of Malta face high levels of water stress due to low rainfall over a small land area and a high population density. We investigate an innovative, cost-effective approach to groundwater monitoring in an island environment by computing auto- and cross-correlations of ambient seismic noise recorded on short-period and broadband seismic stations. While borehole readings give accurate site-specific water level data of the groundwater across the islands, this technique provides a more regional approach to quantitative groundwater monitoring. We perform the moving window cross-spectral method to determine temporal changes in seismic velocity (δv/v). Comparison of the δv/v with groundwater levels from boreholes and precipitation shows comparable patterns. We find that the variations of the δv/v from auto-correlations are more pronounced than the cross-correlation, and that short-period seismic stations are also sensitive. The δv/v signal deteriorates at longer interstation distances, presumably because paths traverse complex geology. We conclude that changes in the groundwater level found beneath very small islands, even as small as 3 km2, can be detected seismically. Low-cost, easy-to-deploy seismic stations can thus act as an additional tool for groundwater monitoring, especially in places with limited natural water reservoirs, like rivers and lakes, and infrastructure.

Since approximately 75% of Europeans currently live in cities, and this number will rise, urban areas are the most important testbeds for energy transition, climate change adaptation measures, and decarbonisation models, on which studies and efforts for concrete change must focus. The teaching of mitigation and adaptation measures to climate change and decarbonisation models has gradually taken up space within university courses. However, the complexity of the decarbonisation issue is raising awareness on the urgency of an interdisciplinary approach that can be conveyed by spatial planning. Currently, this approach is not widespread in Higher Education Institutions in Europe but is nonetheless necessary to let new professional profiles emerge who are able to coordinate different stakeholders, data, and information sources. The Erasmus+ project CITY MINDED (2020–2022) has worked in this direction, by developing and testing a methodology for the design of a structured ordinary practice for teaching urban decarbonisation to students in Higher Education. This practice (at the same time, interdisciplinary, collaborative, experiential, and place-based) aims to offer students a combination of different approaches and working methods to investigate and improve urban neighbourhoods and districts, resulting in the definition of an operative roadmap for decarbonisation in the medium-to-long-term. The aim of this article is to highlight the learning-by-doing experience developed by the project consortium, with reference to the testing of the methodology conducted within an Intensive Course in the City of Valletta (Malta). In particular, the paper illustrates how this experience succeeded in stimulating students with different academic backgrounds to establish connections across disciplines, in raising their awareness about the complexity of city decarbonisation processes. Overcoming the strict time and budget constraints of an EU-funded project, such an approach can be further developed, replicated on theoretical grounds, and implemented within different degree programmes dealing with urban sustainability.

While we increasingly turn to desalination as a secure water supply, it is still perceived as an expensive and environmentally damaging solution, affordable only for affluent societies. In this contribution, we recast desalination from one of a last resort to a far-reaching, climate change mitigating, water security solution.First, we argue that the benefits of desalination go beyond the single-use value of the water produced. If coupled with water reuse for irrigation, desalination reduces groundwater abstraction and augments the water cycle. As such, it may support both adaptation to, and mitigation of climate change impacts by deploying plentiful water for human use, with all the benefits that entails, while helping preserve and restore ecosystems.Second, we counter two arguments commonly raised against desalination, namely its environmental impact and high cost.The environmental impact can be fully controlled so as not to pose long-term threats, if driven by renewable energy. Desalination may then have a zero carbon footprint. Moreover, appropriately designed outfalls make the disposal of brine at sea compatible with marine ecosystems.. Recovery of energy, minerals and more water from brine reject (particularly in the form of vapour for cooling to enable more crops and vegetation to grow), while possible, is often hardly economically justified. However, resource recovery may become more attractive in the future, and help reduce the brine volumes to dispose of.When fresh water becomes scarce, its cost tends to go up, making desalination increasingly economic. Moreover, desalination can have virtually no environmental costs. Considering the environmental costs of over-abstraction of freshwater, desalination tilts the balance in its favour.

The last 60 years has seen unprecedented groundwater extraction and overdraft as well as development of new technologies for water treatment that together drive the advance in intentional groundwater replenishment known as managed aquifer recharge (MAR). This paper is the first known attempt to quantify the volume of MAR at global scale, and to illustrate the advancement of all the major types of MAR and relate these to research and regulatory advancements. Faced with changing climate and rising intensity of climate extremes, MAR is an increasingly important water management strategy, alongside demand management, to maintain, enhance and secure stressed groundwater systems and to protect and improve water quality. During this time, scientific research—on hydraulic design of facilities, tracer studies, managing clogging, recovery efficiency and water quality changes in aquifers—has underpinned practical improvements in MAR and has had broader benefits in hydrogeology. Recharge wells have greatly accelerated recharge, particularly in urban areas and for mine water management. In recent years, research into governance, operating practices, reliability, economics, risk assessment and public acceptance of MAR has been undertaken. Since the 1960s, implementation of MAR has accelerated at a rate of 5%/year, but is not keeping pace with increasing groundwater extraction. Currently, MAR has reached an estimated 10 km3/year, ~2.4% of groundwater extraction in countries reporting MAR (or ~1.0% of global groundwater extraction). MAR is likely to exceed 10% of global extraction, based on experience where MAR is more advanced, to sustain quantity, reliability and quality of water supplies.