scholarly journals Editor’s Message: 25 years of Hydrogeology Journal

2017 ◽  
Vol 25 (8) ◽  
pp. 2217-2220
Author(s):  
Clifford I. Voss ◽  
A. C. Skinner
Keyword(s):  
Hydrogeology Journal

Revised hydrogeological model of the hydrothermal system Waiwera (New Zealand)

2021 ◽  
Author(s):  
Andreas Grafe ◽  
Thomas Kempka ◽  
Michael Schneider ◽  
Michael Kühn
Keyword(s):  
Water Management ◽  
New Zealand ◽  
Water Level ◽  
Hot Water ◽  
Hydrogeology Journal ◽  
Natural State ◽  
Geothermal System ◽  
Geological Model ◽  
Species Transport ◽  
Study Region

<p>The geothermal hot water reservoir underlying the coastal township of Waiwera, northern Auckland Region, New Zealand, has been commercially utilized since 1863. The reservoir is complex in nature, as it is controlled by several coupled processes, namely flow, heat transfer and species transport. At the base of the aquifer, geothermal water of around 50°C enters. Meanwhile, freshwater percolates from the west and saltwater penetrates from the sea in the east. Understanding of the system’s dynamics is vital, as decades of unregulated, excessive abstraction resulted in the loss of previously artesian conditions. To protect the reservoir and secure the livelihoods of businesses, a Water Management Plan by The Auckland Regional Council was declared in the 1980s [1]. In attempts to describe the complex dynamics of the reservoir system with the goal of supplementing sustainable decision-making, studies in the past decades have brought forth several predictive models [2]. These models ranged from being purely data driven statistical [3] to fully coupled process simulations [1].<br><br>Our objective was to improve upon previous numerical models by introducing an updated geological model, in which the findings of a recently undertaken field campaign were integrated [4]. A static 2D Model was firstly reconstructed and verified to earlier multivariate regression model results. Furthermore, the model was expanded spatially into the third dimension. In difference to previous models, the influence of basic geologic structures and the sea water level onto the geothermal system are accounted for. Notably, the orientation of dipped horizontal layers as well as major regional faults are implemented from updated field data [4]. Additionally, the model now includes the regional topography extracted from a digital elevation model and further combined with the coastal bathymetry. Parameters relating to the hydrogeological properties of the strata along with the thermophysical properties of water with respect to depth were applied. Lastly, the catchment area and water balance of the study region are considered.<br><br>The simulation results provide new insights on the geothermal reservoir’s natural state. Numerical simulations considering coupled fluid flow as well as heat and species transport have been carried out using the in-house TRANSport Simulation Environment [5], which has been previously verified against different density-driven flow benchmarks [1]. The revised geological model improves the agreement between observations and simulations in view of the timely and spatial development of water level, temperature and species concentrations, and thus enables more reliable predictions required for water management planning.<br><br>[1] Kühn M., Stöfen H. (2005):<br>      Hydrogeology Journal, 13, 606–626,<br>      https://doi.org/10.1007/s10040-004-0377-6<br><br>[2] Kühn M., Altmannsberger C. (2016):<br>      Energy Procedia, 97, 403-410,<br>      https://doi.org/10.1016/j.egypro.2016.10.034<br><br>[3] Kühn M., Schöne T. (2017):<br>      Energy Procedia, 125, 571-579,<br>      https://doi.org/10.1016/j.egypro.2017.08.196<br><br>[4] Präg M., Becker I., Hilgers C., Walter T.R., Kühn M. (2020):<br>      Advances in Geosciences, 54, 165-171,<br>      https://doi.org/10.5194/adgeo-54-165-2020<br><br>[5] Kempka T. (2020):<br>      Adv. Geosci., 54, 67–77,<br>      https://doi.org/10.5194/adgeo-54-67-2020</p>

Reviewing our options: How can we address climate change impacts in hydrogeological studies?

2020 ◽  
Author(s):  
Steffen Birk ◽  
Raoul Collenteur
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Regional Climate ◽  
Climate Change Impacts ◽  
Regional Climate Models ◽  
Hydrogeology Journal ◽  
Strong Increase ◽  
Emission Scenarios ◽  
Climate Change Research ◽  
Model Chain

<p>Arguably, the groundwater community has responded more slowly to the challenges posed by climate change than other fields of (hydrological) science. However, in recent years a strong increase in studies addressing climate change impacts on groundwater is observed, and recommendations on the methodology of such studies have been developed and discussed (e.g. Holman et al., Hydrogeology Journal, 2012). Following the common practice in other fields of climate change research, it was suggested that assessments of climate change impacts on groundwater should be based on multiple emission scenarios and a range of global and regional climate models. This scenario-based, top-down approach involves the propagation of multi-model ensembles through a model chain starting from emission scenarios to global and regional climate models to impact models such as hydrological and groundwater models. However, as the uncertainty increases at each step of the model chain, the uncertainty in the assessment of local climate change impacts and the resulting recommendations for adaptation options likely are very high and thus of little use in practice. A vulnerability-based, bottom-up approach starting from the identification and analysis of the factors that are relevant for coping with climate change in a given system, therefore, was proposed as a complementary approach (e.g. Wilby and Dessai, Weather, 2010). “Storylines” (Shephard et al., Climatic Change, 2018) that aim at representing uncertainty in physical aspects of climate change in an event-based rather than probabilistic way appear to be consistent with the latter concept. In this poster we relate these concepts of climate change research to methodological frameworks established in hydrogeological research (e.g. multi-model approaches). We present an overview of potential tools, such as trading-space-for-time, historical data analysis, sensitivity analysis, climate projections and controlled experiments, that can be used to study climate change impacts, and we discuss their role and applicability within more general methodological frameworks.</p>

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