Advances in Groundwater Quality and Protection for Sustainability

The impact type and magnitude of global phenomena, including climate change, on water resources around the world usually become discernible with time difference. The incubation period tends to be longer in groundwater than surface water, both quantitatively and qualitatively, due to its physical location. Furthermore, technology deficiency and lack of interests in the pre-water security era left the world little data on the ‘initial state’ of groundwater; therefore, the impact analysis of recent hydrogeological changes are more of an estimation under many assumptions than scientific observation. Thus, much remains unexplored about the subsurface groundwater, with many of important questions are yet answered: how it is formed, how it interacts with surroundings under effects of climate change, pollution, and contamination, how it should be managed, protected and recovered, and more.

If it was just the hardship, groundwater investigation may be a subject of competition, like space or oil exploration; however, water security is a matter of life or death beyond growth or prosperity, and water issues are on the global agenda. Groundwater constitutes one significant pillar of water resources, which holds enormous potential for climate adaptation and sustainable energy. From what has been revealed so far, groundwater can contribute to addressing extreme droughts, floods, and water quality maintenance if managed and used wisely. The cost advantage of groundwater for its quality further offers a path to water justice. Particularly in areas with poor water resources, where there is no specific freshwater source, groundwater’s cost advantage surpasses alternative water resources, such as seawater desalination and rainwater reuse. For these multi-faceted natures, the groundwater investigation requires a well-coordinated multi- and interdisciplinary approach and, thus, calls for collective intellectual efforts to compare and contrast available observational, analytical data around the world to reach the best estimation together. This is the motivation and intention of this Special Issue on “Advances in groundwater quality and protection for sustainability”.

In a nutshell, mid-to-long-term cooperation plans and advanced research projects at the international level that consider hydrogeological characteristics and the surrounding ecological environment comprehensively are required. Academia needs to raise voices for the decision-makers to listen: the sustainability of groundwater is uncertain under climate crises because a lot is still unknown. A long-term observation and research studies should begin as soon as possible accounting the time scale of groundwater flow and time required for sufficient systematic data accumulation. Analysis of the spatial distribution of groundwater, differences in the characteristics of aquifers, and socio-economic factors based on the use and development of water resources are also of importance. Identifying the relationship between agricultural fields and groundwater, and quantitatively evaluating and understanding the ecological function of groundwater in the hydrological cycle are tasks that must be prioritized. This Special Issue is looking for a boundless sense of responsibility and mission of scientists for the sustainability of groundwater resources for future generations. The aim is to share knowledge through this Special Issue to offer a good starting point for scientists, researchers, and policymakers towards water security for sustainability.