Author(s): Angelos N. Findikakis; Nadim K Copty; et al.
This special Groundwater issue of Hydrolink includes articles that exemplify the wide range of issues and ongoing research activities relating to the field of Groundwater. Daniele Tonina describes the presence of hyporheic flows between stream waters and the sediments underneath. This hyporheic exchange of water brings solutes and suspended matter from stream waters into the underlying sediments where important geochemical reactions occur. These transformations can have significant impacts on microorganisms and water quality. The article by Nahed Ben-Salem et al examines the water quality of one of the main Wadis flowing into the Gulf of Tunis in the Mediterranean Basin. It investigates the main sources of the pollution and the potential contamination of underlying groundwater resources. These two articles highlight the interaction between surface and subsurface waters which in the past has often been ignored.
One of the most challenging groundwater contamination problems is the remediation of the groundwater and soil contaminated by hydrocarbons in the form of non-aqueous phase liquids (NAPLs). Because of their low solubility and low biodegradation potential, many of these compounds once released can persist in the subsurface environment for decades or even centuries, contaminating large volumes of the aquifer. The article of Geoffrey Tick provides a comprehensive review of promising technologies for the remediation of NAPL source zones.
Aquifer systems involve numerous stakeholders often with competing interests and goals. These diverging goals can lead to conflicts, particularly in water scarce regions of the world. The article by Dalila Loudyi et al discusses the water stresses that Morocco faces. It proposes the implementation of a “participative water management contract” to help alleviate some of the conflicts between different stakeholders that have arisen in the past. As noted earlier, extensive use of groundwater resources has contributed significantly to the economic development of numerous regions of the world. This however has led to sharp depletion of the water resource in many parts of the world. The article by Eduardo Cassiraga et al describes the extensive exploitation of the East Mancha Aquifer System in Spain and how stakeholders have successfully come together to better manage this system and reverse some of the adverse trends of the past years.
In recent decades significant progress has been made in the field of groundwater flow and contaminant transport modelling. In real life problems, a major challenge remains, the lack of data to fully describe the heterogeneous subsurface system and the complex biochemical processes occurring within. The article by Alberto Guadagnini et al. discusses the uncertainties involved in the characterization of subsurface systems and the need for the quantification of these uncertainties across various scales and for assessing the implications of these uncertainties. Christina Stylianoudaki et al present an application of artificial neural networks (ANN) for predicting nitrate concentrations in the groundwater. ANN are a class of data-driven easy to use models that attempt to quantify correlations between different variables without the need to solve complex physics-based models that are not fully characterized.
Human-induced climate change has emerged in recent years as a major threat to the well-being of our planet. As an integral component of the global water cycle, groundwater resources in many regions of the world will unequivocally be adversely impacted through diminished precipitation, extended droughts, frequent flooding and seawater rise. The article by Glen Walker et al discusses the potential adverse effects that climate change is predicted to have on groundwater resources in southern Australia. It highlights some of the adaptive measures that are being considered and that can serve as a guide for the protection of this vital resource in other water-stressed regions of the world.
The articles published in this issue provide a sample of the broad range of ongoing research in understanding the behaviour of groundwater systems and developing methods for safeguarding and managing sustainably this valuable resource.