Klaus Hinsby | GEUS Geological Survey of Denmark and Greenland (original) (raw)
Papers by Klaus Hinsby
IOP Conference Series: Earth and Environmental Science, 2009
Hydrology and Earth System Sciences, 2012
Intensive farming has severe impacts on the chemical status of groundwater and streams and conseq... more Intensive farming has severe impacts on the chemical status of groundwater and streams and consequently on the ecological status of dependent ecosystems. Eutrophication is a widespread problem in lakes and marine waters. Common problems are hypoxia, algal blooms, fish kills, and loss of water clarity, underwater vegetation, biodiversity and recreational value. In this paper we evaluate the nitrogen (N) and phosphorus (P) concentrations of groundwater and surface water in a coastal catchment, the loadings and sources of N and P, and their effect on the ecological status of an estuary. We calculate the necessary reductions in N and P loadings to the estuary for obtaining a good ecological status, which we define based on the number of days with N and P limitation, and the corresponding stream and groundwater threshold values assuming two different management options. The calculations are performed by the combined use of empirical models and a physically based 3-D integrated hydrological model of the whole catchment. The assessment of the ecological status indicates that the N and P loads to the investigated estuary should be reduced to levels corresponding to 52 and 56 % of the current loads, respectively, to restore good ecological status. Model estimates show that threshold total N (TN) concentrations should be in the range of 2.9 to 3.1 mg l −1 in inlet freshwater (streams) to Horsens estuary and 6.0 to 9.3 mg l −1 in shallow aerobic groundwater (∼ 27-41 mg l −1 of nitrate), depending on the management measures implemented in the catchment. The situation for total P (TP) is more complex, but data indicate that groundwater threshold values are not needed. The stream threshold value for TP to Horsens estuary for the selected management options is 0.084 mg l −1. Regional climate models project increasing winter precipitation and runoff in the investigated region resulting in increasing runoff and nutrient loads to the Horsens estuary and many other coastal waters if present land use and farming practices continue. Hence, lower threshold values are required in many coastal catchments in the future to ensure good status of water bodies and ecosystems. Published by Copernicus Publications on behalf of the European Geosciences Union. K. Hinsby et al.: Threshold values and management options for nutrients Field Drain pipe Horsens Estuary A er o b ic A n ae ro b ic Reg iona l grou ndw ater bod y Reg iona l grou ndw ater bod y Con ning layer (clayey till) Groundwater body (sand) Riparian Area Aquifer Aerobic Anaerobic Redox boundary Dee p gro und wat er bod y Dee p gro und wat er bod y
Hydrology and Earth System Sciences, 2012
Geophysical techniques are increasingly being used as tools for characterising the subsurface, an... more Geophysical techniques are increasingly being used as tools for characterising the subsurface, and they are generally required to develop subsurface models that properly delineate the distribution of aquifers and aquitards, salt/freshwater interfaces, and geological structures that affect groundwater flow. In a study area covering 730 km 2 across the border between Germany and Denmark, a combination of an airborne electromagnetic survey (performed with the SkyTEM system), a high-resolution seismic survey and borehole logging has been used in an integrated mapping of important geological, physical and chemical features of the subsurface. The spacing between flight lines is 200-250 m which gives a total of about 3200 line km. About 38 km of seismic lines have been collected. Faults bordering a graben structure, buried tunnel valleys, glaciotectonic thrust complexes, marine clay units, and sand aquifers are all examples of geological structures mapped by the geophysical data that control groundwater flow and to some extent hydrochemistry. Additionally, the data provide an excellent picture of the salinity distribution in the area and thus provide important information on the salt/freshwater boundary and the chemical status of groundwater. Although the westernmost part of the study area along the North Sea coast is saturated with saline water and the TEM data therefore are strongly influenced by the increased electrical conductivity there, buried valleys and other geological elements are still revealed. The mapped salinity distribution indicates preferential flow paths through and along specific geological structures within the area. The effects of a future sea level rise on the groundwater system and groundwater chemistry are discussed with special emphasis on the importance of knowing the existence, distribution and geometry of the mapped geological elements, and their control on the groundwater salinity distribution is assessed.
Water Resources Research, 2007
Vertical profiles of the chlorofluorocarbons CFC-11, CFC-12, and CFC-113 penetrating aerobic and ... more Vertical profiles of the chlorofluorocarbons CFC-11, CFC-12, and CFC-113 penetrating aerobic and anaerobic parts of a shallow sandy aquifer show that the CFC gases are degraded in the <1 m thick transition zone from aerobic to anaerobic groundwater in a pyritic sand aquifer at Rabis Creek, Denmark. Two-dimensional solute transport simulations with either zero-order or first-order degradation in the anaerobic
Vadose Zone Journal, 2004
Geological Survey of Denmark and Greenland Bulletin, Aug 15, 2018
Water
High levels of inorganic compounds in groundwater represent a significant problem in many parts o... more High levels of inorganic compounds in groundwater represent a significant problem in many parts of the world, with major economic, social and environmental drawbacks [...]
<p>In order to assess the anthropogenic impacts on groundwa... more <p>In order to assess the anthropogenic impacts on groundwater quality we generally need to identify the natural conditions or Natural background levels (NBLs) within groundwater systems, which are used as references to assess the evolution of the contamination status. This information, in addition to the threshold values (TVs), which are derived from NBLs and based on specific criteria values for legitimate water uses and the environment (terrestrial and aquatic ecosystems), is required to appropriately assess of the chemical status of groundwater in accordance with the European Water Framework Directive and to analyse and propose potential measures where they are required.</p><p>In literature, different methodologies are available to assess NBLs and reference TVs for different geochemical substances based on the available measurements of groundwater salinity (e.g. based on probability plots). In this work we analyze and compare three previously proposed methods for derivation of chloride NBLs, which is a conservation solute and is closely related to salt water intrusion in inland and coastal aquifers. We discuss and compare their applicability in pilots located in different settings (southern /northern European / Mediteranean/ North Sea /Baltic Sea) covering different typologies (detrital, karstic, fissured aquifers) and management issues (overexploitation, land use and land cover changes, etc). We perform sensitivity analysis to different constraints applied to remove samples affected by human activity (Nitrate and the brackish saline constraints) in the assessment of NBLs. Finally, based on this analysis, we propose a general approach for derivation of NBLs that could be applied to any of the tested pilots as well as other similar settings in Europe.</p><p> </p><p>This research has been partially supported by the SIGLO-AN project (RTI2018-101397-B-I00) from the Spanish Ministry of Science, Innovation and Universities (Programa Estatal de I+D+I orientada a los Retos de la Sociedad).</p><p>This work has been partially supported by the GeoE.171.008-TACTIC and GeoE.171.008-HOVER projects from GeoERA organization funded by European Union’s Horizon 2020 research and innovation program.</p>
<p>Denitrification potential is an important parameter to know for ... more <p>Denitrification potential is an important parameter to know for adequate and efficient management and assessment of groundwater vulnerability and chemical status. Denitrification removes nitrate in groundwater, but the denitrification capacity is highly variable in space and time, and it may be used up with time. When linking pressure and impact the effect of partial or complete denitrification and denitrification capacity should be taken into account. In some areas, denitrification is seen as an advantage, allowing higher N release below soil without leading to a decrease of the groundwater quality and eventually concentrations in groundwater higher than the WFD and DWD threshold values, which EU member states have to establish to protect drinking water and groundwater dependent terrestrial and associated aquatic ecosystems.    </p><p>Within the GEOERA HOVER project, the aim was to assess the spatial extent and importance of denitrification. The studied cases permitted at a first step to highlight the heterogeneities of the approaches due to the variability of information obtained i.e. the likelihood of denitrification, depth and thickness of redox transition zone, complete denitrification status. The parameters used to define the denitrification vary also from one country to another based on a large set of redox sensitive ions (Eh, O<sub>2</sub>, NO<sub>3</sub>, NO<sub>2</sub>, Fe, Mn, SO<sub>4</sub>, CH<sub>4</sub>, δ<sup>18</sup>O<sub>-NO3</sub> et δ<sup>15</sup>N-<sub>NO3</sub>, H<sub>2</sub>S or N<sub>2</sub>). Some of these parameters can be accessed by standard methods in most laboratories, used for groundwater quality monitoring, while others require specialized analysis and interpretations.</p><p>Considering groundwater and hydrogeological data available in most of the EU countries, a simple method is proposed in order to classify the monitoring points into three classes: oxic, anoxic and mixed. After being tested in different well-known areas the method will be applied in various lithologies and hydrogeological contexts The proposed method will enable the development of European maps supporting groundwater quality management across Europe.</p>
<p&amp... more <p>Groundwater dating and travel time distributions are important tools and data for assessment of the vulnerability of water supply wells towards pollution from the surface. Here we present selected results from more than 30 water supply and monitoring wells from major Danish water companies. The wells were recently sampled and investigated using multiple environmental tracers including <sup>85</sup>Kr, <sup>39</sup>Ar, <sup>3</sup>H/<sup>3</sup>He, <sup>14</sup>C, SF<sub>6</sub>, CFCs and noble gases and different groundwater modeling techniques. The results demonstrate the value of groundwater dating and travel time estimations for the assessment of the history and fate of contaminants in the subsurface. This information is crucial for the assessment of the efficiency of measures to mitigate pollution of groundwater by harmful substances such as pesticides, nitrate and a large range of emerging contaminants. We demonstrate how groundwater ages and travel time distributions can be used to assess the vulnerability or susceptibility of water supply wells towards pollution, and how level specific sampling in long well screens can provide additional important information for assessment of the vulnerability of deep and shallow parts of a water supply well. Potential applications of the estimated travel time distributions include 1) improved management of well fields 2) development of pumping strategies and well screens minimizing the risk of pollution of drinking water wells, and 3) assessment of the adequacy of regulations established by authorities to protect valuable groundwater resources against pollution.   </p>
&... more <p>Climate change (CC) already have widespread and significant impacts in Europe, which is expected to increase in the future. Groundwater plays a vital role for the land phase of the freshwater cycle and have the capability of buffering or enhancing the impact from extreme climate events causing droughts or floods, depending on the subsurface properties and the status of the system (dry/wet) prior to the climate event. Understanding and taking the hydrogeology into account is therefore essential in the assessment of climate change impacts.</p> <p>The Geological Survey Organisations (GSOs) in Europe compile the necessary data and knowledge of the groundwater systems across Europe. The overall vision of the project “Tools for Assessment of ClimaTe change ImpacT on Groundwater and Adaptation Strategies – TACTIC” is to enhance the utilisation of these data and knowledge of the subsurface system in CC impact assessments, and the identification and analyses of potential adaptation strategies. To reach this vision, the objective of TACTIC is to contribute to the development of coherent and transparent assessments of CC impacts on groundwater and surface water, supporting improved EU policy making, and providing decision support for stakeholders and decision makers. To accomplish this, an infra-structure among European Geological Survey Organisations are developed in TACTIC to foster advancement and harmonisation of CC assessments, made up by: 1) The TACTIC Toolbox, consisting of relevant tools and methods for CC impact assessments, 2) TACTIC guidelines that will guide GSOs and other relevant stakeholders on the selection of appropriate tools and their use for producing comparable results, 3) The European Geological Data Infrastructure (EGDI) where data, reports and open-access papers will be stored  and made freely available  </p> <p>The project is centred around 40 pilot studies covering a variety of CC challenges as well as different hydrogeological settings and different management systems found in Europe. The pilot activities are coordinated centrally in the project, to ensure that assessments, to the extent possible, are harmonised and can be compared across pilots. Synthesizing the experiences and results from the pilots will enable the development of a guideline and future roadmap, with the aim of 1) encouraging more GSOs to contribute in CC impact assessments 2) providing guidance to make the learning curve less steep and 3)ensuring that new assessments are comparable with assessments conducted in TACTIC.</p> <p>TACTIC is part of the Horizon 2020 ERA-NET on Applied Geoscience (GeoERA) and together with the three other GeoERA groundwater projects, TACTIC will provide new and important data for further development of the European Geological Data Infrastructure (EGDI) with publicly available data enabling the development of EU-wide decision support systems for sustainable management of subsurface resources in a changing…
Effective porosity plays an important role in contaminant management. However, the effective poro... more Effective porosity plays an important role in contaminant management. However, the effective porosity is often assumed constant in space and hence either neglected or simplified in transport model calibration. Based on a calibrated highly parametrized flow model, a three-dimensional advective transport model (MODPATH) of a 1300 km 2-large coastal area of southern Denmark and northern Germany is presented. A detailed voxel model represents the highly heterogeneous geological composition of the area. Inverse modelling of advective transport is used to estimate seven, spatially distributed, effective porosity units based on apparent groundwater ages inferred from 11 14 C measurements in Pleistocene and Miocene aquifers, corrected for the effects of diffusion and geochemical reactions. The match between the observed and simulated ages is improved significantly by the calibration of seven porosity units by a reduction of ME of 99% and RMS of 82% compared to a uniform porosity approach. Groundwater ages range from a few hundred years in the Pleistocene to several thousand years in Miocene aquifers. The advective age distributions derived from particle tracking at each sampling well show unimodal (for younger ages) to multimodal (for older ages) shapes and thus reflect the heterogeneity that particles encounter along their travel path. The estimated effective porosity field, with values ranging between 4.3% in clay and 45% in sand formations, is used in a direct simulation of distributed mean groundwater ages. Although the absolute ages are affected by various uncertainties, a unique insight into the complex three-dimensional age distribution pattern and potential advance of young contaminated groundwater in the investigated regional aquifer system is provided, highlighting the importance of estimating effective porosity in groundwater transport modelling and the implications for groundwater quantity and quality assessment and management.
Geological Society London Special Publications, 2001
ABSTRACT Modem groundwater that has recharged aquifers within the past 50 a shows the influence o... more ABSTRACT Modem groundwater that has recharged aquifers within the past 50 a shows the influence of humans globally, either by the presence of small concentrations of environmental tracers or in some cases by severe pollution. This study describes important environmental tracers (e.g. 3H, 85Kr, chlorofluorocarbons, SF6) and contaminants (e.g. NO3-, pesticides, chlorinated solvents) for modem groundwater dating and recognition of human impacts. Some applications of the described tracers in aquifers investigated in the PALAEAUX study are presented in order to illustrate the advance of modem waters in European aquifer systems. The study shows that the location of the modern water interface varies within a range of between c. 10 and c. 100 m in the investigated aquifers due to variations in hydrogeological setting, climate and exploitation of the groundwater resource. The subsurface distribution of the modem water indicators and contaminants demonstrate that the advance of modem groundwaters and the fate of harmful substances in them have important implications for protection and development of the water resources. Contaminants that do not degrade or degrade only very slowly will advance further into the aquifers and may eventually contaminate even deep groundwater systems.
ABSTRACT The EU Water Framework and Groundwater Directives outline an approach to water admini-st... more ABSTRACT The EU Water Framework and Groundwater Directives outline an approach to water admini-stration in which interactions between groundwater bodies, groundwater dependent terrestrial ecosystems and surface water bodies (associated aquatic ecosystems) take on a central role. To facilitate monitoring and status assessment the directives allow grouping according to typologies. A typology used for evaluating interdependency between groundwater bodies, riparian areas and streams must be based on processes controlling flow, contaminant transport and attenuation. The typology of Groundwater – Surface water Interaction (GSI typology) has been developed as a process oriented scaled framework classifying interactions between the three hydrological components. The controlling processes are characterised using an eco-hydrological approach based on geomorphology, hydrogeological setting and flow paths on gradually smaller scales. As part of a programme of measures to obtain good ecological status of associated coastal waters (including a Natura 2000 site) an assessment was conducted in a 50 km 2 catchment area in a moraine landscape by combined use of new developments of the GSI typology and a field campaign of nitrate concentration measurements in groundwater, tributaries and streams. One purpose was to delineate sub-catchments in which nitrate concentrations in a shallow local groundwater body exceeded threshold values derived from good status objectives for the coastal ecosystems. Another purpose was to assess in which selected sub-catchments riparian area hydrology restorations or reductions in nitrate input from fields were appropriate measures to reduce nitrate loads to streams and ultimately to the associated coastal waters.
ABSTRACT Peter Scharling (1), Klaus Hinsby (2), and Kelsy Brennan (3) (1) COWI, Lyngby, Denmark (... more ABSTRACT Peter Scharling (1), Klaus Hinsby (2), and Kelsy Brennan (3) (1) COWI, Lyngby, Denmark (pesh@cowi.dk), (2) Geologial Survey of Denmark and Greenland (GEUS), Hydrology, Copenhagen, Denmark (khi@geus.dk), (3) Earthfx Inc., Toronto, Canada (kelsy@earthfx.com) A web server framework for rich interactive access to geologic and water quality data. Geodata visualization and analysis is founded on proper access to all available data. Throughout several research projects Earthfx and GEUS managed to gather relevant data from both national and local databases into one platform. The web server platform which is easy accessible on the internet displays all types of spatially distributed geodata ranging from geochemistry, geological and geophysical well logs, surface-and airborne geophysics to any type of temporal measurements like water levels and trends in groundwater chemistry. Geological cross sections are an essential tool for the geoscientist. Moving beyond plan-view web mapping, GEUS and Earthfx have developed a webserver technology that provides the user with the ability to dynamically interact with geologic models developed for various projects in Denmark and in transboundary aquifers across the Danish-German border. The web map interface allows the user to interactively define the location of a multi-point profile, and the selected profile will be quickly drawn and illustrated as a slice through the 3D geologic model. Including all borehole logs within a user defined offset from the profile. A key aspect of the webserver technology is that the profiles are presented through a fully dynamic interface. Web users can select and interact with borehole logs contained in the underlying database, adjust vertical exaggeration, and add or remove off-section boreholes by dynamically adjusting the offset projection distance. In a similar manner to the profile tool, an interactive water level and water chemistry graphing tool has been integrated into the web service interface. Again, the focus is on providing a level of functionality beyond simple data display. Future extensions to the web interface and functionality are possible, as the web server utilizes the same code engine that is used for desktop geologic model construction and water quality data management. In summary, the GEUS/Earthfx web server tools demonstrate that a rich interaction with geologic models and borehole data is possible through a web interface. Examples from existing and active homepages will be shown.
IOP Conference Series: Earth and Environmental Science, 2009
Hydrology and Earth System Sciences, 2012
Intensive farming has severe impacts on the chemical status of groundwater and streams and conseq... more Intensive farming has severe impacts on the chemical status of groundwater and streams and consequently on the ecological status of dependent ecosystems. Eutrophication is a widespread problem in lakes and marine waters. Common problems are hypoxia, algal blooms, fish kills, and loss of water clarity, underwater vegetation, biodiversity and recreational value. In this paper we evaluate the nitrogen (N) and phosphorus (P) concentrations of groundwater and surface water in a coastal catchment, the loadings and sources of N and P, and their effect on the ecological status of an estuary. We calculate the necessary reductions in N and P loadings to the estuary for obtaining a good ecological status, which we define based on the number of days with N and P limitation, and the corresponding stream and groundwater threshold values assuming two different management options. The calculations are performed by the combined use of empirical models and a physically based 3-D integrated hydrological model of the whole catchment. The assessment of the ecological status indicates that the N and P loads to the investigated estuary should be reduced to levels corresponding to 52 and 56 % of the current loads, respectively, to restore good ecological status. Model estimates show that threshold total N (TN) concentrations should be in the range of 2.9 to 3.1 mg l −1 in inlet freshwater (streams) to Horsens estuary and 6.0 to 9.3 mg l −1 in shallow aerobic groundwater (∼ 27-41 mg l −1 of nitrate), depending on the management measures implemented in the catchment. The situation for total P (TP) is more complex, but data indicate that groundwater threshold values are not needed. The stream threshold value for TP to Horsens estuary for the selected management options is 0.084 mg l −1. Regional climate models project increasing winter precipitation and runoff in the investigated region resulting in increasing runoff and nutrient loads to the Horsens estuary and many other coastal waters if present land use and farming practices continue. Hence, lower threshold values are required in many coastal catchments in the future to ensure good status of water bodies and ecosystems. Published by Copernicus Publications on behalf of the European Geosciences Union. K. Hinsby et al.: Threshold values and management options for nutrients Field Drain pipe Horsens Estuary A er o b ic A n ae ro b ic Reg iona l grou ndw ater bod y Reg iona l grou ndw ater bod y Con ning layer (clayey till) Groundwater body (sand) Riparian Area Aquifer Aerobic Anaerobic Redox boundary Dee p gro und wat er bod y Dee p gro und wat er bod y
Hydrology and Earth System Sciences, 2012
Geophysical techniques are increasingly being used as tools for characterising the subsurface, an... more Geophysical techniques are increasingly being used as tools for characterising the subsurface, and they are generally required to develop subsurface models that properly delineate the distribution of aquifers and aquitards, salt/freshwater interfaces, and geological structures that affect groundwater flow. In a study area covering 730 km 2 across the border between Germany and Denmark, a combination of an airborne electromagnetic survey (performed with the SkyTEM system), a high-resolution seismic survey and borehole logging has been used in an integrated mapping of important geological, physical and chemical features of the subsurface. The spacing between flight lines is 200-250 m which gives a total of about 3200 line km. About 38 km of seismic lines have been collected. Faults bordering a graben structure, buried tunnel valleys, glaciotectonic thrust complexes, marine clay units, and sand aquifers are all examples of geological structures mapped by the geophysical data that control groundwater flow and to some extent hydrochemistry. Additionally, the data provide an excellent picture of the salinity distribution in the area and thus provide important information on the salt/freshwater boundary and the chemical status of groundwater. Although the westernmost part of the study area along the North Sea coast is saturated with saline water and the TEM data therefore are strongly influenced by the increased electrical conductivity there, buried valleys and other geological elements are still revealed. The mapped salinity distribution indicates preferential flow paths through and along specific geological structures within the area. The effects of a future sea level rise on the groundwater system and groundwater chemistry are discussed with special emphasis on the importance of knowing the existence, distribution and geometry of the mapped geological elements, and their control on the groundwater salinity distribution is assessed.
Water Resources Research, 2007
Vertical profiles of the chlorofluorocarbons CFC-11, CFC-12, and CFC-113 penetrating aerobic and ... more Vertical profiles of the chlorofluorocarbons CFC-11, CFC-12, and CFC-113 penetrating aerobic and anaerobic parts of a shallow sandy aquifer show that the CFC gases are degraded in the <1 m thick transition zone from aerobic to anaerobic groundwater in a pyritic sand aquifer at Rabis Creek, Denmark. Two-dimensional solute transport simulations with either zero-order or first-order degradation in the anaerobic
Vadose Zone Journal, 2004
Geological Survey of Denmark and Greenland Bulletin, Aug 15, 2018
Water
High levels of inorganic compounds in groundwater represent a significant problem in many parts o... more High levels of inorganic compounds in groundwater represent a significant problem in many parts of the world, with major economic, social and environmental drawbacks [...]
<p>In order to assess the anthropogenic impacts on groundwa... more <p>In order to assess the anthropogenic impacts on groundwater quality we generally need to identify the natural conditions or Natural background levels (NBLs) within groundwater systems, which are used as references to assess the evolution of the contamination status. This information, in addition to the threshold values (TVs), which are derived from NBLs and based on specific criteria values for legitimate water uses and the environment (terrestrial and aquatic ecosystems), is required to appropriately assess of the chemical status of groundwater in accordance with the European Water Framework Directive and to analyse and propose potential measures where they are required.</p><p>In literature, different methodologies are available to assess NBLs and reference TVs for different geochemical substances based on the available measurements of groundwater salinity (e.g. based on probability plots). In this work we analyze and compare three previously proposed methods for derivation of chloride NBLs, which is a conservation solute and is closely related to salt water intrusion in inland and coastal aquifers. We discuss and compare their applicability in pilots located in different settings (southern /northern European / Mediteranean/ North Sea /Baltic Sea) covering different typologies (detrital, karstic, fissured aquifers) and management issues (overexploitation, land use and land cover changes, etc). We perform sensitivity analysis to different constraints applied to remove samples affected by human activity (Nitrate and the brackish saline constraints) in the assessment of NBLs. Finally, based on this analysis, we propose a general approach for derivation of NBLs that could be applied to any of the tested pilots as well as other similar settings in Europe.</p><p> </p><p>This research has been partially supported by the SIGLO-AN project (RTI2018-101397-B-I00) from the Spanish Ministry of Science, Innovation and Universities (Programa Estatal de I+D+I orientada a los Retos de la Sociedad).</p><p>This work has been partially supported by the GeoE.171.008-TACTIC and GeoE.171.008-HOVER projects from GeoERA organization funded by European Union’s Horizon 2020 research and innovation program.</p>
<p>Denitrification potential is an important parameter to know for ... more <p>Denitrification potential is an important parameter to know for adequate and efficient management and assessment of groundwater vulnerability and chemical status. Denitrification removes nitrate in groundwater, but the denitrification capacity is highly variable in space and time, and it may be used up with time. When linking pressure and impact the effect of partial or complete denitrification and denitrification capacity should be taken into account. In some areas, denitrification is seen as an advantage, allowing higher N release below soil without leading to a decrease of the groundwater quality and eventually concentrations in groundwater higher than the WFD and DWD threshold values, which EU member states have to establish to protect drinking water and groundwater dependent terrestrial and associated aquatic ecosystems.    </p><p>Within the GEOERA HOVER project, the aim was to assess the spatial extent and importance of denitrification. The studied cases permitted at a first step to highlight the heterogeneities of the approaches due to the variability of information obtained i.e. the likelihood of denitrification, depth and thickness of redox transition zone, complete denitrification status. The parameters used to define the denitrification vary also from one country to another based on a large set of redox sensitive ions (Eh, O<sub>2</sub>, NO<sub>3</sub>, NO<sub>2</sub>, Fe, Mn, SO<sub>4</sub>, CH<sub>4</sub>, δ<sup>18</sup>O<sub>-NO3</sub> et δ<sup>15</sup>N-<sub>NO3</sub>, H<sub>2</sub>S or N<sub>2</sub>). Some of these parameters can be accessed by standard methods in most laboratories, used for groundwater quality monitoring, while others require specialized analysis and interpretations.</p><p>Considering groundwater and hydrogeological data available in most of the EU countries, a simple method is proposed in order to classify the monitoring points into three classes: oxic, anoxic and mixed. After being tested in different well-known areas the method will be applied in various lithologies and hydrogeological contexts The proposed method will enable the development of European maps supporting groundwater quality management across Europe.</p>
<p&amp... more <p>Groundwater dating and travel time distributions are important tools and data for assessment of the vulnerability of water supply wells towards pollution from the surface. Here we present selected results from more than 30 water supply and monitoring wells from major Danish water companies. The wells were recently sampled and investigated using multiple environmental tracers including <sup>85</sup>Kr, <sup>39</sup>Ar, <sup>3</sup>H/<sup>3</sup>He, <sup>14</sup>C, SF<sub>6</sub>, CFCs and noble gases and different groundwater modeling techniques. The results demonstrate the value of groundwater dating and travel time estimations for the assessment of the history and fate of contaminants in the subsurface. This information is crucial for the assessment of the efficiency of measures to mitigate pollution of groundwater by harmful substances such as pesticides, nitrate and a large range of emerging contaminants. We demonstrate how groundwater ages and travel time distributions can be used to assess the vulnerability or susceptibility of water supply wells towards pollution, and how level specific sampling in long well screens can provide additional important information for assessment of the vulnerability of deep and shallow parts of a water supply well. Potential applications of the estimated travel time distributions include 1) improved management of well fields 2) development of pumping strategies and well screens minimizing the risk of pollution of drinking water wells, and 3) assessment of the adequacy of regulations established by authorities to protect valuable groundwater resources against pollution.   </p>
&... more <p>Climate change (CC) already have widespread and significant impacts in Europe, which is expected to increase in the future. Groundwater plays a vital role for the land phase of the freshwater cycle and have the capability of buffering or enhancing the impact from extreme climate events causing droughts or floods, depending on the subsurface properties and the status of the system (dry/wet) prior to the climate event. Understanding and taking the hydrogeology into account is therefore essential in the assessment of climate change impacts.</p> <p>The Geological Survey Organisations (GSOs) in Europe compile the necessary data and knowledge of the groundwater systems across Europe. The overall vision of the project “Tools for Assessment of ClimaTe change ImpacT on Groundwater and Adaptation Strategies – TACTIC” is to enhance the utilisation of these data and knowledge of the subsurface system in CC impact assessments, and the identification and analyses of potential adaptation strategies. To reach this vision, the objective of TACTIC is to contribute to the development of coherent and transparent assessments of CC impacts on groundwater and surface water, supporting improved EU policy making, and providing decision support for stakeholders and decision makers. To accomplish this, an infra-structure among European Geological Survey Organisations are developed in TACTIC to foster advancement and harmonisation of CC assessments, made up by: 1) The TACTIC Toolbox, consisting of relevant tools and methods for CC impact assessments, 2) TACTIC guidelines that will guide GSOs and other relevant stakeholders on the selection of appropriate tools and their use for producing comparable results, 3) The European Geological Data Infrastructure (EGDI) where data, reports and open-access papers will be stored  and made freely available  </p> <p>The project is centred around 40 pilot studies covering a variety of CC challenges as well as different hydrogeological settings and different management systems found in Europe. The pilot activities are coordinated centrally in the project, to ensure that assessments, to the extent possible, are harmonised and can be compared across pilots. Synthesizing the experiences and results from the pilots will enable the development of a guideline and future roadmap, with the aim of 1) encouraging more GSOs to contribute in CC impact assessments 2) providing guidance to make the learning curve less steep and 3)ensuring that new assessments are comparable with assessments conducted in TACTIC.</p> <p>TACTIC is part of the Horizon 2020 ERA-NET on Applied Geoscience (GeoERA) and together with the three other GeoERA groundwater projects, TACTIC will provide new and important data for further development of the European Geological Data Infrastructure (EGDI) with publicly available data enabling the development of EU-wide decision support systems for sustainable management of subsurface resources in a changing…
Effective porosity plays an important role in contaminant management. However, the effective poro... more Effective porosity plays an important role in contaminant management. However, the effective porosity is often assumed constant in space and hence either neglected or simplified in transport model calibration. Based on a calibrated highly parametrized flow model, a three-dimensional advective transport model (MODPATH) of a 1300 km 2-large coastal area of southern Denmark and northern Germany is presented. A detailed voxel model represents the highly heterogeneous geological composition of the area. Inverse modelling of advective transport is used to estimate seven, spatially distributed, effective porosity units based on apparent groundwater ages inferred from 11 14 C measurements in Pleistocene and Miocene aquifers, corrected for the effects of diffusion and geochemical reactions. The match between the observed and simulated ages is improved significantly by the calibration of seven porosity units by a reduction of ME of 99% and RMS of 82% compared to a uniform porosity approach. Groundwater ages range from a few hundred years in the Pleistocene to several thousand years in Miocene aquifers. The advective age distributions derived from particle tracking at each sampling well show unimodal (for younger ages) to multimodal (for older ages) shapes and thus reflect the heterogeneity that particles encounter along their travel path. The estimated effective porosity field, with values ranging between 4.3% in clay and 45% in sand formations, is used in a direct simulation of distributed mean groundwater ages. Although the absolute ages are affected by various uncertainties, a unique insight into the complex three-dimensional age distribution pattern and potential advance of young contaminated groundwater in the investigated regional aquifer system is provided, highlighting the importance of estimating effective porosity in groundwater transport modelling and the implications for groundwater quantity and quality assessment and management.
Geological Society London Special Publications, 2001
ABSTRACT Modem groundwater that has recharged aquifers within the past 50 a shows the influence o... more ABSTRACT Modem groundwater that has recharged aquifers within the past 50 a shows the influence of humans globally, either by the presence of small concentrations of environmental tracers or in some cases by severe pollution. This study describes important environmental tracers (e.g. 3H, 85Kr, chlorofluorocarbons, SF6) and contaminants (e.g. NO3-, pesticides, chlorinated solvents) for modem groundwater dating and recognition of human impacts. Some applications of the described tracers in aquifers investigated in the PALAEAUX study are presented in order to illustrate the advance of modem waters in European aquifer systems. The study shows that the location of the modern water interface varies within a range of between c. 10 and c. 100 m in the investigated aquifers due to variations in hydrogeological setting, climate and exploitation of the groundwater resource. The subsurface distribution of the modem water indicators and contaminants demonstrate that the advance of modem groundwaters and the fate of harmful substances in them have important implications for protection and development of the water resources. Contaminants that do not degrade or degrade only very slowly will advance further into the aquifers and may eventually contaminate even deep groundwater systems.
ABSTRACT The EU Water Framework and Groundwater Directives outline an approach to water admini-st... more ABSTRACT The EU Water Framework and Groundwater Directives outline an approach to water admini-stration in which interactions between groundwater bodies, groundwater dependent terrestrial ecosystems and surface water bodies (associated aquatic ecosystems) take on a central role. To facilitate monitoring and status assessment the directives allow grouping according to typologies. A typology used for evaluating interdependency between groundwater bodies, riparian areas and streams must be based on processes controlling flow, contaminant transport and attenuation. The typology of Groundwater – Surface water Interaction (GSI typology) has been developed as a process oriented scaled framework classifying interactions between the three hydrological components. The controlling processes are characterised using an eco-hydrological approach based on geomorphology, hydrogeological setting and flow paths on gradually smaller scales. As part of a programme of measures to obtain good ecological status of associated coastal waters (including a Natura 2000 site) an assessment was conducted in a 50 km 2 catchment area in a moraine landscape by combined use of new developments of the GSI typology and a field campaign of nitrate concentration measurements in groundwater, tributaries and streams. One purpose was to delineate sub-catchments in which nitrate concentrations in a shallow local groundwater body exceeded threshold values derived from good status objectives for the coastal ecosystems. Another purpose was to assess in which selected sub-catchments riparian area hydrology restorations or reductions in nitrate input from fields were appropriate measures to reduce nitrate loads to streams and ultimately to the associated coastal waters.
ABSTRACT Peter Scharling (1), Klaus Hinsby (2), and Kelsy Brennan (3) (1) COWI, Lyngby, Denmark (... more ABSTRACT Peter Scharling (1), Klaus Hinsby (2), and Kelsy Brennan (3) (1) COWI, Lyngby, Denmark (pesh@cowi.dk), (2) Geologial Survey of Denmark and Greenland (GEUS), Hydrology, Copenhagen, Denmark (khi@geus.dk), (3) Earthfx Inc., Toronto, Canada (kelsy@earthfx.com) A web server framework for rich interactive access to geologic and water quality data. Geodata visualization and analysis is founded on proper access to all available data. Throughout several research projects Earthfx and GEUS managed to gather relevant data from both national and local databases into one platform. The web server platform which is easy accessible on the internet displays all types of spatially distributed geodata ranging from geochemistry, geological and geophysical well logs, surface-and airborne geophysics to any type of temporal measurements like water levels and trends in groundwater chemistry. Geological cross sections are an essential tool for the geoscientist. Moving beyond plan-view web mapping, GEUS and Earthfx have developed a webserver technology that provides the user with the ability to dynamically interact with geologic models developed for various projects in Denmark and in transboundary aquifers across the Danish-German border. The web map interface allows the user to interactively define the location of a multi-point profile, and the selected profile will be quickly drawn and illustrated as a slice through the 3D geologic model. Including all borehole logs within a user defined offset from the profile. A key aspect of the webserver technology is that the profiles are presented through a fully dynamic interface. Web users can select and interact with borehole logs contained in the underlying database, adjust vertical exaggeration, and add or remove off-section boreholes by dynamically adjusting the offset projection distance. In a similar manner to the profile tool, an interactive water level and water chemistry graphing tool has been integrated into the web service interface. Again, the focus is on providing a level of functionality beyond simple data display. Future extensions to the web interface and functionality are possible, as the web server utilizes the same code engine that is used for desktop geologic model construction and water quality data management. In summary, the GEUS/Earthfx web server tools demonstrate that a rich interaction with geologic models and borehole data is possible through a web interface. Examples from existing and active homepages will be shown.