This study focuses on the optimization of open-loop shallow geothermal systems to improve their efficiency and sustainability. Different approaches to solve optimization problems in this field are explored, their strengths and limitations are highlighted, and recommendations are given for their use and future developments. The study can be a valuable basis for researchers and practitioners involved in the management and optimization of shallow geothermal systems.

A multi-salinity experiment was conducted in three tight clay-bearing (kaolinite, chlorite, and glauconite) sandstones to study the impact of clay on their petrophysical properties. Chlorite sandstone presented higher electrochemical interaction, followed by glauconite and kaolinite. In the geothermal context, this investigation highlights the importance of ensuring that the correct fluid chemistry is used in clay-bearing geothermal reservoirs.

We studied and mapped the ground deformation in Catania plain in Italy using artificial intelligence techniques applied to displacement time series of Sentinel-1 satellites. We estimated the dates when the velocities of displacement time series changed. We observed significant land subsidence in the south part of Catania Airport and showed how the precipitation cycles and trend change had a potential impact on ground deformation.

To ensure the effective and sustainable operation of water exploitation projects, it is imperative to select appropriate extraction technologies.

15ky ago a great eruption occurred in the Campi Flegrei. The Neapolitan Yellow Tuff, produced by this eruption extended itself for more than 1000 km² and represents an easily recognizable level both in the Tyrrhenian Sea and on land. Here, through a seismostratigraphic study, we have identified and described the extension of these deposits in the Gulf of Gaeta. Knowing the areal extension of the Campi Flegrei eruptions deposits, helps to build volcanic risk maps for an area densely populated.

Waiwera is a small coastal village located on New Zealand's North Island above a geothermal reservoir. The origin of the warm water is not well understood. An inferred fault zone at the base of the reservoir is thought to channelise the uprising thermal water. The observed characteristic cold and hot water distribution in the system was simulated and the temperature profiles show an improved agreement in the near field around the centre of the reservoir.

Our study addresses the challenges of costly groundwater investigation in the catchments by integrating in-situ groundwater data with terrain classification. This approach allows us to identify terrain-based groundwater potential and characterize groundwater levels. We aim for our findings to guide ongoing researchers in planning more detailed studies within their respective areas. These insights contribute to sustainable groundwater management and resource planning in similar topographies.

To combat global warming and achieve net-zero CO₂ emissions by 2050, Carbon Capture and Storage (CCS) is vital. Despite being a top CO₂ emitter globally, Brazil is early in its CCS journey. Our study evaluates the potential of using southern Brazil's saline aquifers for CO₂ storage with the aim of supporting Brazil’s efforts to reduce emissions and mitigate climate change. We identify optimal storage sites in two basins, Paraná and Espírito Santo, with ideal locations near existing pipelines. 

The impacts of climate change have become increasingly apparent, even in Slovakia. To monitor and issue drought warnings, we conduct analyses and prepare documents. Our analysis, covering the last decade (2013-2022) and 2022, provides a map of surface and groundwater abstractions throughout Slovakia, categorized by sector. This comprehensive approach enables us to better understand and manage our water resources effectively.

Scaling, particularly calcium carbonate precipitation in Bavaria, diminishes the efficiency of geothermal systems. To mitigate this issue, modeling for predictive maintenance is required, yet data are scarce. To address this, experimental data of the process were obtained using a new combination that allows qualitative and quantitative investigation in real time. Unfortunately, the stability of the signal degraded in long-term experiments, limiting measurements to durations of up to one day.

Water is historically abundant in Northern Italy, but it was hit by a major meteorological drought recently. In this study, a possible adaptation measure to these extreme events is proposed and evaluated: the flooding of fields during periods of water abundance to recharge aquifers. Results show that the measure has a considerable potential in infiltrating high volumes of water. This work only shows the first results, more data and improved numerical models will be achieved in the next years.

This study proposes an offline machine-learning (ML) algorithm that ranks candidate training points by scoring them based on their distance to the closest training point and on the local gradient of the surrogate estimate and then choosing the highest-rank point. The effectiveness of this method is confirmed in developing surrogates to solve a two-objective groundwater pumping optimization problem formulated on a three-dimensional island aquifer.

As groundwater serves as the principal source of water worldwide, its quality is of paramount importance. In this study, the evolution of groundwater quality in California is assessed using the Water Quality Index & Weighted Index Overlay Analysis methods. Several water quality parameters are considered for the analysis, and the results from both methods are compared. The study shows that in most parts of California, groundwater quality is potable, as per WHO guidelines, except in a few places. 

Dealing with the sociotechnical system of nuclear waste needs an integrated perspective. Its global blockage is due to the neglect of relevant issues. The concept of sustainability (passive protection & control) suggests itself as a reference, enabling a stepwise analysis of dimensions: beyond the triad of ecological/economical/social, also temporal, spatial, technical, political, ethical. The proposal avoids simple complexity reduction, either “technical” or “social fix” (volunteers first). 

In Colombia there are many areas with little or no hydrometeorological information that would allow for adequate water resource management, especially in times of low supply of the resource. In this work, several modeling techniques are implemented to generate data grids of meteorological variables that allow for reliable calculations of the potential recharge of aquifers, controlling uncertainties.

Future glaciations can affect the long-term safety of deep geological repositories for nuclear waste. This study introduces a simple method to assess frequency and duration of ice sheets over the next one million years at locations with past glaciations. The method considers uncertainties in human-caused CO₂ emissions and climate change. It is easy to implement for any nuclear waste management organization that need to consider impacts of future ice sheets on long-term safety.

We examined how water quality in aquifers and streams varies along the Besòs catchment, and changes in streams during wet and dry periods. Analysis of water quality data (2013-2023) in open databases shows nutrients and salinity increase towards the outlet, and more markedly during dry periods. Since such dry periods may become more frequent with climate change in this Mediterranean basin, this highlights the importance of controlling pollution sources affecting water quality and availability.

To operate aquifer thermal energy storages in a sustainable way, we located an artesian aquifer other than the aquifer storage in a research wellbore by analyzing the subsurface temperature as monitored with a fiber optic cable in three artesian flow tests. The positioning of the artesian aquifer was validated via numerical modelling. Analyses of the temperature data and numerical modelling enabled determining the profile of flow velocity, flow rate and the depth interval of inflow.

This paper presents a surrogate modelling approach applied to a geochemical system of uranium sorption on clay, relevant for the safety assessment of nuclear waste repositories. The surrogate uses knowledge about the underlying process to recursively partition the dataset into regions of reduced dimensionality. It achieves high accuracy with a competitive prediction throughput, and is a promising method to speedup  computationally demanding coupled reactive transport models.

Storm Daria was a severe winter storm that crossed northern Europe on 25–26 January 1990 with large damage costs and fatalities.  A literature review is presented of societal damage and the interruption of energy and transport networks.  Met-ocean data is analyzed to see if there might have been rogue wave strikes in the North Sea.  This includes careful analysis of tide gauge data from stations around the North Sea as well as available offshore wave measurements and maritime accidents.   

Concepts of High-Temperature Aquifer Thermal Energy Storage (HT-ATES) are investigated for system application in the German Molasse Basin. We quantify via physics-based numerical modelling the system performance with respect to HT-ATES concept development and provide a predictive analysis of HT-ATES application in the Upper Jurassic reservoir. Results demonstrate a non-uniform layer-specific distribution of the thermal front propagation, while promising heat recovery efficiencies are predicted.