New data for a model update of the Waiwera geothermal reservoir in New Zealand
Michael Kühn
CORRESPONDING AUTHOR
GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany
University of Potsdam, Institute of Geosciences, Potsdam, 14476, Germany
Vaughan Stagpoole
GNS Science, Private Bag 2000, Taupō 3352, New Zealand
Graham Paul D. Viskovic
GNS Science, Private Bag 2000, Taupō 3352, New Zealand
Thomas Kempka
GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany
University of Potsdam, Institute of Geosciences, Potsdam, 14476, Germany
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The present study, uses density-driven flow and transport models to evaluate mechanisms of saline water intrusion from deep aquifers into the freshwater column used for drinking water supply under different boundary conditions and for a specific site in the German Federal State of Brandenburg. Results show that mainly decreasing groundwater recharge leads to increased and earlier salinisation which highlights the need for waterworks to initiate effective countermeasures quickly and in time.
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The geothermal hot water reservoir below the small town of Waiwera in New Zealand has been known to the indigenous Maori for many centuries. Overproduction by European immigrants led to a water level decrease and consequently artesian flow from the wells and the seeps on the beach ceased. The Te Kaunihera o Tāmaki Makaurau Auckland Council established the Waiwera Thermal Groundwater Allocation and Management Plan to allow the geothermal system to recover.
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The geothermal reservoir at Waiwera has been subject to active exploitation for a long time. However, the continuous production of geothermal water, to supply hotels and spas, had a negative impact on the reservoir. The aim of this work was to link the influence of the abstraction rates to the measured water level data to derive reservoir properties. For the analysis, a modified deconvolution algorithm was implemented and shown to be applicable and in accordance to results of a pumping test.
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Uranium migration in the Swiss Opalinus Clay is used as an example to quantify the influence of varying values of a stability constant in the underlying thermodynamic database within the law of mass action on the migration lengths. The difference of the stability constant of 1.33 log units lead to changed migration lengths of 5 m to 7 m. With a maximum diffusion distance of 22 m the influence of an uncertain stability constant is negligible for the host rock scale.
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Short summary
Short summary
Uranium migration for a close to real case situation is quantified with reactive transport simulations using input data from the deep geothermal borehole Schlattingen, which is near the targeted area in Switzerland, and including the effect of the multi-barrier system on the source term. The hydrogeological system must always be considered in safety assessments since adjacent aquifers have a major impact on the pore water geochemistry, and hence sorption processes.
Theresa Hennig and Michael Kühn
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Short summary
Short summary
Migration of uranium in the potential host rock Opalinus Clay is used as an example to demonstrate the extent to which simulated migration lengths can vary for a million years, depending on the model concept and on the underlying data and parameters. To reduce the uncertainty in this context, the calcite carbonate ion and the hydrogeological system at a potential disposal site need to be known, whereas the quantity of clay minerals plays a subordinate role, as long as it is enough.
Michael Kühn, Dirk Bosbach, Horst Geckeis, Vinzenz Brendler, and Olaf Kolditz
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Short summary
Short summary
The Repository Site Selection Act explicitly emphasises that targeting the disposal of high-level radioactive waste is a so-called learning process. We are of the opinion that the procedure and the available data should be combined with geoscientific knowledge to support the identification of siting regions. We propose this workshop and invite all experts who have dealt with the search for a repository site from a geoscientific perspective.
Viktor J. Bruckman, Gregor Giebel, Christopher Juhlin, Sonja Martens, and Michael Kühn
Adv. Geosci., 58, 87–91, https://doi.org/10.5194/adgeo-58-87-2022, https://doi.org/10.5194/adgeo-58-87-2022, 2022
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The quantification of the impacts on the environment and human health is a crucial prerequisite for geological sub-surface utilisation projects. With the presented approach, the shortcomings of using conceptually simplified models are substantially reduced, since subsurface complexities are accounted for. The transparency of the assessment basis should generally increase the acceptance of geoengineering projects, considered one of the crucial aspects for geological subsurface utilisation.
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For a potential utilisation of coal resources located in Hungary, an assessment of groundwater pollution resulting from a water-borne contaminant pool has been undertaken. A sensitivity analysis was carried out by means of numerical simulations. Simulation results demonstrate that fluid flow via the regional faults is the main driver for a potential contamination of shallow groundwater aquifers. A parameter correlation analysis is presented.
Elena Chabab, Michael Kühn, and Thomas Kempka
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The present study, uses density-driven flow and transport models to evaluate mechanisms of saline water intrusion from deep aquifers into the freshwater column used for drinking water supply under different boundary conditions and for a specific site in the German Federal State of Brandenburg. Results show that mainly decreasing groundwater recharge leads to increased and earlier salinisation which highlights the need for waterworks to initiate effective countermeasures quickly and in time.
Michael Kühn, Melissa Präg, Ivy Becker, Christoph Hilgers, Andreas Grafe, and Thomas Kempka
Adv. Geosci., 58, 31–39, https://doi.org/10.5194/adgeo-58-31-2022, https://doi.org/10.5194/adgeo-58-31-2022, 2022
Short summary
Short summary
The geothermal hot water reservoir below the small town of Waiwera in New Zealand has been known to the indigenous Maori for many centuries. Overproduction by European immigrants led to a water level decrease and consequently artesian flow from the wells and the seeps on the beach ceased. The Te Kaunihera o Tāmaki Makaurau Auckland Council established the Waiwera Thermal Groundwater Allocation and Management Plan to allow the geothermal system to recover.
Thomas Kempka, Svenja Steding, and Michael Kühn
Adv. Geosci., 58, 19–29, https://doi.org/10.5194/adgeo-58-19-2022, https://doi.org/10.5194/adgeo-58-19-2022, 2022
Short summary
Short summary
The TRANSPORT Simulation Environment (TRANSPORTSE) was coupled with the geochemical reaction module PHREEQC, providing multiple new features that make it applicable to complex reactive transport problems in various geoscientific fields. Two computationally demanding and complex geochemical benchmarks were used in the present study to successfully verify the code implementation.
Theresa Hennig and Michael Kühn
Adv. Geosci., 58, 11–18, https://doi.org/10.5194/adgeo-58-11-2022, https://doi.org/10.5194/adgeo-58-11-2022, 2022
Short summary
Short summary
Safety assessments must demonstrate that radionuclides in potential disposal sites are retained within the containment providing rock zone using reactive transport simulations. Here, this is quantified for the example of uranium in the hydrogeological system of the Opalinus Clay at Mont Terri. Our work clearly shows how sensitive migration lengths resulting from simulations are to the model conceptualisation and selection of underlying data.
Maria Wetzel, Thomas Kempka, and Michael Kühn
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Porosity-permeability relations are simulated for a precipitation-dissolution cycle in a virtual sandstone. A hysteresis in permeability is observed depending on the geochemical process and dominating reaction regime, whereby permeability varies by more than two orders of magnitude. Controlling parameters for this hysteresis phenomenon are the closure and re-opening of micro-scale flow channels, derived from changes in pore throat diameter and connectivity of the pore network.
Marco De Lucia, Michael Kühn, Alexander Lindemann, Max Lübke, and Bettina Schnor
Geosci. Model Dev., 14, 7391–7409, https://doi.org/10.5194/gmd-14-7391-2021, https://doi.org/10.5194/gmd-14-7391-2021, 2021
Short summary
Short summary
POET is a parallel reactive transport simulator which implements a mechanism to store and reuse previous results of geochemical simulations through distributed hash tables. POET parallelizes chemistry using a master/worker design with noncontiguous grid partitions to maximize its efficiency and load balance on shared-memory machines and compute clusters.
Michael Kühn and Leonard Grabow
Adv. Geosci., 56, 107–116, https://doi.org/10.5194/adgeo-56-107-2021, https://doi.org/10.5194/adgeo-56-107-2021, 2021
Short summary
Short summary
The geothermal reservoir at Waiwera has been subject to active exploitation for a long time. However, the continuous production of geothermal water, to supply hotels and spas, had a negative impact on the reservoir. The aim of this work was to link the influence of the abstraction rates to the measured water level data to derive reservoir properties. For the analysis, a modified deconvolution algorithm was implemented and shown to be applicable and in accordance to results of a pumping test.
Dirk Bosbach, Horst Geckeis, Frank Heberling, Olaf Kolditz, Michael Kühn, Katharina Müller, Thorsten Stumpf, and the iCROSS team
Saf. Nucl. Waste Disposal, 1, 85–87, https://doi.org/10.5194/sand-1-85-2021, https://doi.org/10.5194/sand-1-85-2021, 2021
Short summary
Short summary
The present contribution provides an overview on the collaborative project iCROSS and reports selected results. The impact of considering complex coupled processes in repository subsystems for the assessment of the integrity of a given (generic) repository arrangement will be discussed. The interdisciplinary team combines experimental work in the lab, in the underground rock laboratory and environmental simulations in order to achieve process understanding across variable scales.
Theresa Hennig and Michael Kühn
Adv. Geosci., 56, 97–105, https://doi.org/10.5194/adgeo-56-97-2021, https://doi.org/10.5194/adgeo-56-97-2021, 2021
Short summary
Short summary
Uranium migration in the Swiss Opalinus Clay is used as an example to quantify the influence of varying values of a stability constant in the underlying thermodynamic database within the law of mass action on the migration lengths. The difference of the stability constant of 1.33 log units lead to changed migration lengths of 5 m to 7 m. With a maximum diffusion distance of 22 m the influence of an uncertain stability constant is negligible for the host rock scale.
Morgan Tranter, Maria Wetzel, Marco De Lucia, and Michael Kühn
Adv. Geosci., 56, 57–65, https://doi.org/10.5194/adgeo-56-57-2021, https://doi.org/10.5194/adgeo-56-57-2021, 2021
Short summary
Short summary
Barite formation is an important factor for many use cases of the geological subsurface because it may change the rock.
In this modelling study, the replacement reaction of celestite to barite is investigated.
The steps that were identified to play a role are celestite dissolution followed by two-step precipitation of barite: spontaneous formation of small crystals and their subsequent growth.
Explicitly including the processes improve the usability of the models for quantified prediction.
Marco De Lucia and Michael Kühn
Adv. Geosci., 56, 33–43, https://doi.org/10.5194/adgeo-56-33-2021, https://doi.org/10.5194/adgeo-56-33-2021, 2021
Short summary
Short summary
RedModRphree is an R extension package to leverage the PHREEQC engine for geochemical models, providing convenience functions to efficiently setup computations and program algorithms involving geochemical models. Version 0.3.6 ships with a novel implementation of Pourbaix (potential/pH) diagram computation which considers the full speciation of the solution at each diagram point.
Viktor J. Bruckman, Gregor Giebel, Christopher Juhlin, Sonja Martens, Antonio P. Rinaldi, and Michael Kühn
Adv. Geosci., 56, 13–18, https://doi.org/10.5194/adgeo-56-13-2021, https://doi.org/10.5194/adgeo-56-13-2021, 2021
Marco De Lucia and Michael Kühn
Geosci. Model Dev., 14, 4713–4730, https://doi.org/10.5194/gmd-14-4713-2021, https://doi.org/10.5194/gmd-14-4713-2021, 2021
Short summary
Short summary
DecTree evaluates a hierarchical coupling method for reactive transport simulations in which pre-trained surrogate models are used to speed up the geochemical subprocess, and equation-based
full-physicssimulations are called only if the surrogate predictions are implausible. Furthermore, we devise and evaluate a decision tree surrogate approach designed to inject domain knowledge of the surrogate by defining engineered features based on law of mass action or stoichiometric reaction equations.
Melissa Präg, Ivy Becker, Christoph Hilgers, Thomas R. Walter, and Michael Kühn
Adv. Geosci., 54, 165–171, https://doi.org/10.5194/adgeo-54-165-2020, https://doi.org/10.5194/adgeo-54-165-2020, 2020
Short summary
Short summary
Utilization of geothermal reservoirs as alternative energy source is becoming increasingly important worldwide. Here, we studied the surface expression of a warm water reservoir in Waiwera, New Zealand, that has been known for many centuries but remained little explored. Using thermal infrared cameras we were able to show renewed activity of the hot springs on the beachfront and identified faults and fractures as important fluid pathways, as well as individual fluid conducting lithologies.
Michael Kühn, Natalie C. Nakaten, and Thomas Kempka
Adv. Geosci., 54, 173–178, https://doi.org/10.5194/adgeo-54-173-2020, https://doi.org/10.5194/adgeo-54-173-2020, 2020
Short summary
Short summary
Energy supply in Germany is subject to a profound change. The present paper addresses the German potential of storing excess energy from renewable power sources in the geological subsurface. Wind and solar electricity can be transformed into hydrogen, and with carbon dioxide subsequently into methane. The current potential for combined subsurface storage of methane and carbon dioxide allows to store far more than required to date and is estimated to provide the entire coverage in 2050.
Thomas Kempka
Adv. Geosci., 54, 67–77, https://doi.org/10.5194/adgeo-54-67-2020, https://doi.org/10.5194/adgeo-54-67-2020, 2020
Short summary
Short summary
The TRANsport Simulation Environment (TRANSE) has been developed to improve the flexibility for coupling chemical libraries with fluid flow and the transport of heat and chemical species. The Python-based implementation of TRANSE enables users not experienced in low-level programming languages (e.g., C, C++ or FORTRAN) to undertake required code modifications and integrate chemical modules as required. TRANSE has been successfully verified against benchmarks on density-driven fluid flow.
Maria Wetzel, Thomas Kempka, and Michael Kühn
Adv. Geosci., 54, 33–39, https://doi.org/10.5194/adgeo-54-33-2020, https://doi.org/10.5194/adgeo-54-33-2020, 2020
Sonja Martens, Maren Brehme, Viktor J. Bruckman, Christopher Juhlin, Johannes Miocic, Antonio P. Rinaldi, and Michael Kühn
Adv. Geosci., 54, 1–5, https://doi.org/10.5194/adgeo-54-1-2020, https://doi.org/10.5194/adgeo-54-1-2020, 2020
Márk Somogyvári, Michael Kühn, and Sebastian Reich
Adv. Geosci., 49, 207–214, https://doi.org/10.5194/adgeo-49-207-2019, https://doi.org/10.5194/adgeo-49-207-2019, 2019
Sonja Martens, Christopher Juhlin, Viktor J. Bruckman, Gregor Giebel, Thomas Nagel, Antonio P. Rinaldi, and Michael Kühn
Adv. Geosci., 49, 31–35, https://doi.org/10.5194/adgeo-49-31-2019, https://doi.org/10.5194/adgeo-49-31-2019, 2019
Michael Kühn and Tim Schöne
Adv. Geosci., 45, 235–241, https://doi.org/10.5194/adgeo-45-235-2018, https://doi.org/10.5194/adgeo-45-235-2018, 2018
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The water level of the Waiwera geothermal reservoir increased in the hours and days after the Kaikoura earthquake on 14 November 2016. We determined in a continuous time series consisting of monthly means of water level data and pumping rates starting in 1986 if events above a certain strength alter groundwater dynamics at Waiwera. A clear correlation cannot be proven but none of the recorded earthquakes led to such a high energy density in Waiwera as the Kaikoura event did.
Sonja Martens, Christopher Juhlin, Viktor J. Bruckman, Kristen Mitchell, Luke Griffiths, and Michael Kühn
Adv. Geosci., 45, 163–166, https://doi.org/10.5194/adgeo-45-163-2018, https://doi.org/10.5194/adgeo-45-163-2018, 2018
Elena Tillner, Maria Langer, Thomas Kempka, and Michael Kühn
Hydrol. Earth Syst. Sci., 20, 1049–1067, https://doi.org/10.5194/hess-20-1049-2016, https://doi.org/10.5194/hess-20-1049-2016, 2016
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The degree of shallow aquifer salinisation triggered by fluid injection into deeper brine-bearing aquifers and brine upward migration through hydraulically conductive faults strongly depends on the regional depth of the freshwater-saltwater boundary, since displaced brines originate only from the upper fault damage zones in the study area. The highest local salinity increase in shallow aquifers occurs in case of closed model boundaries and low fault damage zone volumes.
M. De Lucia, T. Kempka, and M. Kühn
Geosci. Model Dev., 8, 279–294, https://doi.org/10.5194/gmd-8-279-2015, https://doi.org/10.5194/gmd-8-279-2015, 2015
Cited articles
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Short summary
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.
Waiwera is a small coastal village located on New Zealand's North Island above a geothermal...