Rudolf Liedl

Technische Universität Dresden, Dresden, Saxony, Germany

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Publications (112)147.3 Total impact

  • Source
    M Usman · R Liedl · M A Shahid · A Abbas
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    ABSTRACT: Detailed analysis of Land Use/Land Cover (LULC) using remote sensing data in complex irrigated basins provides complete profile for better water resource management and planning. Using remote sensing data, this study provides detailed land use maps of the Lower Chenab Canal irrigated region of Pakistan from 2005 to 2012 for LULC change detection. Major crop types are demarcated by identifying temporal profiles of NDVI using MODIS 250 m  250 m spatial resolution data. Wheat and rice are found to be major crops in rabi and kharif seasons, respectively. Accuracy assessment of prepared maps is performed using three different techniques: error matrix approach, comparison with ancillary data and with previous study. Producer and user accuracies for each class are calculated along with kappa coefficients (K). The average overall accuracies for rabi and kharif are 82.83% and 78.21%, respectively. Producer and user accuracies for individual class range respectively between 72.5% to 77% and 70.1% to 84.3% for rabi and 76.6% to 90.2% and 72% to 84.7% for kharif. The K values range between 0.66 to 0.77 for rabi with average of 0.73, and from 0.69 to 0.74 with average of 0.71 for kharif. LULC change detection indicates that wheat and rice have less volatility of change in comparison with both rabi and kharif fodders. Transformation between cotton and rice is less common due to their completely different cropping conditions. Results of spatial and temporal LULC distributions and their seasonal variations provide useful insights for establishing realistic LULC scenarios for hydrological studies.
    Full-text · Article · Dec 2015 · Journal of Geographical Sciences
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    ABSTRACT: Detailed analysis of Land Use/Land Cover (LULC) using remote sensing data in complex irrigated basins provides complete profile for better water resource management and planning. Using remote sensing data, this study provides detailed land use maps of the Lower Chenab Canal irrigated region of Pakistan from 2005 to 2012 for LULC change detection. Major crop types are demarcated by identifying temporal profiles of NDVI using MODIS 250 m × 250 m spatial resolution data. Wheat and rice are found to be major crops in rabi and kharif seasons, respectively. Accuracy assessment of prepared maps is performed using three different techniques: error matrix approach, comparison with ancillary data and with previous study. Producer and user accuracies for each class are calculated along with kappa coefficients (K). The average overall accuracies for rabi and kharif are 82.83% and 78.21%, respectively. Producer and user accuracies for individual class range respectively between 72.5% to 77% and 70.1% to 84.3% for rabi and 76.6% to 90.2% and 72% to 84.7% for kharif. The K values range between 0.66 to 0.77 for rabi with average of 0.73, and from 0.69 to 0.74 with average of 0.71 for kharif. LULC change detection indicates that wheat and rice have less volatility of change in comparison with both rabi and kharif fodders. Transformation between cotton and rice is less common due to their completely different cropping conditions. Results of spatial and temporal LULC distributions and their seasonal variations provide useful insights for establishing realistic LULC scenarios for hydrological studies.
    Full-text · Article · Nov 2015 · Journal of Geographical Sciences

  • No preview · Article · Oct 2015 · Grundwasser
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    M Usman · R Liedl · M A Shahid · A Abbas
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    ABSTRACT: Detailed analysis of Land Use/Land Cover (LULC) using remote sensing data in complex irrigated basins provides complete profile for better water resource management and planning. Using remote sensing data, this study provides detailed land use maps of the Lower Chenab Canal irrigated region of Pakistan from 2005 to 2012 for LULC change detection. Major crop types are demarcated by identifying temporal profiles of NDVI using MODIS 250 m × 250 m spatial resolution data. Wheat and rice are found to be major crops in rabi and kharif seasons, respectively. Accuracy assessment of prepared maps is performed using three different techniques: error matrix approach, comparison with ancillary data and with previous study. Producer and user accuracies for each class are calculated along with kappa coefficients (K). The average overall accuracies for rabi and kharif are 82.83% and 78.21%, respectively. Producer and user accuracies for individual class range respectively between 72.5% to 77% and 70.1% to 84.3% for rabi and 76.6% to 90.2% and 72% to 84.7% for kharif. The K values range between 0.66 to 0.77 for rabi with average of 0.73, and from 0.69 to 0.74 with average of 0.71 for kharif. LULC change detection indicates that wheat and rice have less volatility of change in comparison with both rabi and kharif fodders. Transformation between cotton and rice is less common due to their completely different cropping conditions. Results of spatial and temporal LULC distributions and their seasonal variations provide useful insights for establishing realistic LULC scenarios for hydrological studies.
    Full-text · Dataset · Sep 2015
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    ABSTRACT: High-resolution depth-oriented temperature measurements have been introduced to investigate a groundwater body in the urban area of Basel. In total, four devices were installed with up to 16 sensors - located in both the saturated and unsaturated zone. Measurements were performed over a period of 4 years and provide sufficient data to set up and calibrate high-resolution numerical local heat-transport models. Calibration was performed for the saturated and unsaturated zone, respectively.
    No preview · Article · Aug 2015 · Energy Procedia
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    ABSTRACT: MODFLOW2005 Conduit Flow Process (CFP) is a numerical hybrid model coupling discrete pipes, which account for laminar and turbulent flow, to a MODFLOW continuum. Such a hybrid model can simulate highly conductive flow paths embedded in a less conductive matrix, for example karst aquifers or mining shafts. Recent additions and enhancements complement the existing CFP functionality by several features and processes (Reimann et al. 2014). For example, the pipe flow model is enhanced by direct storage to account for water abstraction scenarios. In addition, the discrete flow model is extended by heat and solute transport that account for advective-dispersive transport in conduits with process based Taylor dispersion. Moreover, conduit transport options for matrix diffusion (e.g. heat conduction in surrounding rock) or for consideration of continuum transport via a coupled MT3D model are available. Two application examples highlight benefits of the updated CFP. (A) Evaluation of large-scale water abstraction in a karst aquifer demonstrates the model ability to characterize flow systems on different scales, therewith, gaining new insights in the system structure. (B) Combined analysis of spring thermos-, chemo-, and hydrographs by using the hybrid flow and transport model together with inverse modeling (using PEST functionalities) improves identification of complex system patterns. Further information about the modified version of MODFLOW-CFP is available under the internet domain http://www.tu-dresden.de/fghhigw (download section).
    Full-text · Conference Paper · Jun 2015
  • Muhammad Usman · Rudolf Liedl · Usman Khalid Awan

    No preview · Article · Jun 2015 · Journal of Hydrology
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    Muhammad Usman · Rudolf Liedl · Usman Khalid Awan
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    ABSTRACT: Reallocation of water resources in any irrigation scheme is only possible by detailed assessment of current irrigation performance. The performance of the Lower Chenab Canal (LCC) irrigation system in Pakistan was evaluated at large spatial and temporal scales. Evaporative Fraction (EF) representing the key element to assess the three very important performance indicators of equity, adequacy and reliability, was determined by the Surface Energy Balance Algorithm (SEBAL) using Moderate Resolution Imaging Spectroradiometer (MODIS) images. Spatially based estimations were performed at irrigation subdivisions, lower and upper LCC and, whole LCC scales, while temporal scales covered months, seasons and years for the study period from 2005 to 2012. Differences in consumptive water use between upper and lower LCC were estimated for different crops and possible water saving options were explored. The assessment of equitable water distribution indicates smaller coefficients of variation and hence less inequity within each subdivision except Sagar (0.08) and Bhagat (0.10). Both adequacy and reliability of water resources are found lower during kharif as compared to rabi with variation from head to tail reaches. Reliability is quite low from July to September and in February / March. This is mainly attributed to seasonal rainfalls. Average consumptive water use estimations indicate almost doubled water use (546 mm) in kharif as compared to (274 mm) in rabi with significant variability for different cropping years. Crop specific consumptive water use reveals rice 25 and sugarcane as major water consumers with average values of 593 mm and 580 mm, respectively, for upper and lower LCC, followed by cotton and kharif fodder. The water uses for cotton are 555 mm and 528 mm. For kharif fodder, corresponding values are 525 mm and 494 mm for both regions. Based on the differences in consumptive water use, different land use land cover change scenarios were evaluated with regard to savings of crop water. It is found that such analyses need to be complemented at more fine spatial resolutions (i.e irrigation subdivisions).
    Full-text · Article · Jun 2015 · Journal of Hydrology
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    Muhammad Usman · Rudolf Liedl · Alireza Kavousi
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    ABSTRACT: Groundwater is inevitable for agricultural production in the Indus Basin of Pakistan. Its management on sustainable basis is only possible by careful appraisal of its recharge potential and dynamics. This study aimed at exploring pixel-based groundwater recharge at 1 km 2 spatial resolution using remote sensing data through water balance method. Moreover, spatially distributed groundwater abstractions are estimated by new approach with the aid of remote sensing data and results are compared with the conventional utilization factor method. Groundwater abstraction estimation from conventional utilization factor method overstates results both for kharif and rabi cropping seasons. Recharge results obtained from water balance method and water table fluctuation approach are comparable both at irrigation subdivision and 1 km 2 spatial scales. During the kharif cropping seasons, rainfall is the main source of recharge followed by field percolation losses while for rabi cropping seasons, canal seepage remains the major source. Net groundwater recharge is mainly positive during all kharif seasons. A gradual increase in groundwater level is observed in major parts of the study area. Improvement in results from water table fluctuation method is possible by better distribution and increased intensity of piezometers while for water balance approach, it is possible by adopting alternative buffer zones for canal seepage. Detailed sensitivity and uncertainty analyses of input/output variables are needed to present the results with confidence interval and hence to support sustainable and economical operation of irrigation system.
    Full-text · Article · Feb 2015 · Environmental Earth Sciences
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    ABSTRACT: The International Water Research Alliance Saxony (IWAS) is addressing the global challenges concerning water quality in the areas of drinking water and sanitation, agricultural irrigation and the quality of surface and ground waters, as well as developing specific ecosystem-relevant services to be implemented on an exemplary basis in selected model regions. Locations (model regions) have been selected in Eastern Europe (R1), Central and Southeast Asia (R2 and R3), the Middle East (R4) and Latin America (R5) that are representative international regions with respect to climate, land use and demographic change (Ibisch et al., Helmholtz Centre for Environmental Research—UFZ, Department of Aquatic Ecosystem analysis and management, 2013). The causes of water problems and the relevant boundary conditions vary from region to region (Borchardt and Ibisch, Integrated water resources management in a changing world : lessons learnt and innovative perspectives, pp 225, 2013). Mongolia and Vietnam were selected model regions in the first IWAS phase; the research was transferred and continued in one of the cross-cutting projects in IWAS II (Vietnam → capacity development) or in the frame of related project activities in Central Asia (R2 Mongolia, Karthe et al., Environ Earth Sci, doi:10. 1007/ s12665-014-3789-1, 2014). The IWAS consortium exists on scientific institutions like the Technische Universität Dresden and the Helmholtz Centre for Environmental Research—UFZ, Leipzig, as well as partners from industry like the Stadtentwässerung Dresden GmbH (SE-DD), DREBERIS—Dresden consulting for international strategies, and itwh—institute for technical-scientific Hydrology, Hanover. This thematic issue compiles the most important scientific results of the second phase of the IWAS project. The project itself and findings of the first phase were already introduced in a previous special issue by Kalbus et al. (Environ Earth Sci 65:1363–1366, 2012). Main results: The IWAS project is structured by the model regions (R) as well as by cross-cutting activities scenario analysis (Q1), technology development (Q2), governance (Q3) and capacity development (Q4).
    Full-text · Article · Dec 2014 · Environmental Earth Sciences
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    Full-text · Dataset · Sep 2014
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    ABSTRACT: Aquifer storage and recovery (ASR) methods are increasingly used to overcome the temporal imbalance between water demand and availability. Common ASR recharge methods utilize large-diameter injection wells or surface infiltration basins and trenches, and can be costly to implement. A new low-cost ASR recharge method is currently being developed. This approach is based on recharge via gravity in small-diameter wells installed with direct-push (DP) technology. Numerical modeling is used here to assess the potential of this new approach under conditions commonly faced in field settings. The primary objective is to investigate if a battery of small-diameter DP wells can serve as a viable alternative to a surface basin under typical field conditions, while the secondary objective is to assess which subsurface parameters have the greatest control on DP well performance. Simulation results indicate that gravity recharge via small-diameter wells appears to have a distinct advantage over recharge via surface infiltration basins. For example, two 0.05-m shallow vadose-zone wells with 9-m screens can recharge water at a greater rate than a 60 m2 basin. Also, results reveal that, contrary to an infiltration basin, the recharge rate in a DP well has a much stronger dependence on the horizontal component of hydraulic conductivity than on the vertical component. Moreover, near-surface layers of low hydraulic conductivity, which can significantly reduce the recharge capacity of a surface basin, have a relatively small impact on the recharge capacity of a well as long as a significant portion of the well screen is installed below those layers. Given that installation and operation costs can be low in comparison to common ASR recharge methods, this new approach appears to have great potential for recharging good quality water in shallow unconsolidated aquifers. A field investigation has recently been initiated to follow up the findings of this simulation assessment.
    No preview · Article · Sep 2014 · Journal of Hydrology
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    ABSTRACT: In the last ten years (approximately) a lot of natural attenuation scenarios have been modeled under the assumption that the degradation of pollutants occurs mainly at the reaction front. This was particularly facilitated by using numerical methods which readily covers a wide range of different hydrogeological scenarios to predict associated plume length. In contrast, due to experimental difficulties, only part of the scenarios has so far been simulated in laboratory experiments in order to assess the suitability of the models under controlled conditions. This paper deals with the design and evaluation of natural attenuation scenario at laboratory scale in a tank experiment which is based on a vertical 2D experiment (tank dimension 200 cm * 2 cm * 15 cm). The study aims at the maximum spreading of electron donors (contaminant) reacting with the vertically entering electron acceptors (e.g. oxygen). In the experiment, this scenario was simulated by a base-acid pair with pH = 11.3 and pH = 2, respectively. An indicator mixing with both acid and base was used to visualize the reaction front. Glass beads (diameter 1.55 mm to 1.88 mm) was used as porous media. Experiments were evaluated after reaching steady conditions.
    Full-text · Thesis · Apr 2014
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    ABSTRACT: This paper evaluates the remediation potential of a salinized coastal aquifer by utilizing a scenario simulation. Therefore, the numerical model OPENGEOSYS is first validated against analytical and experimental data to represent transient groundwater level development and variable density saline intrusion. Afterwards, a regional scale model with a three-dimensional, heterogeneous hydrogeology is calibrated for a transient state and used to simulate a best-case scenario. Water balances are evaluated in both the transient calibration and scenario run. Visualization techniques help to assess the complex model output providing valuable insight in the occurring density-driven flow processes. Furthermore, modeling and visualization results give information on the time scale for remediation activities and, due to limitations in data quality and quantity reveal potential for model improvement.
    Full-text · Article · Apr 2014 · Environmental Earth Sciences
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    ABSTRACT: Rice and wheat are very important grain crops and are heavily grown in lands between the Ravi and Chenab Rivers in Pakistan. Because rice is generally cultivated under standing water conditions, careful estimation of actual water consumption and crop water productivity (CWP) is key for proper water management. In the current study, an effort is made to estimate actual evapotranspiration (ETa) by using the soil and energy balance algorithm (SEBAL), which used the moderate-resolution imaging spectroradiometer (MODIS) satellite with a spatial resolution of 1,000 m. Rice and wheat crop dominance areas were identified by using the ISODATA crop classification technique by utilizing MODIS normalized difference vegetation index (NDVI) 250 m resolution data. Crop-specific ETa was masked out both for rice and wheat, and this information was utilized with crop yield for estimation of CWP. Tehsil administrative-level crop-yield data were collected and extrapolated to model crop yield on a pixel basis by benefiting from crop yields and specific NDVI empirical relationships. Study results showed a variation of ETa (402–780 and 244–328 mm), yield (823–2,596 and 1,287–3,646 kg/ha), and CWP (0.14–0.56 and 0.54–1.44 kg=m3) for rice and wheat, respectively. Best results were attained for rice in tehsil Hafizabad with a coefficient of variation in CWP of 7.94%. Most of the other tehsils showed higher variability of approximately 16%. The primary cause of lower CWP for rice crop in these tehsils is higher values of ETa (i.e., greater than 600 mm), which is ideal for maximizing CWP in the study region. For the wheat crop, because water consumption is almost similar in all parts and CWP is primarily variable owing to yield differences, this suggested minimum scope for CWP improvement by water management for wheat. Crop cultivation expenditures can be reduced both for rice and wheat by proper application and management of water and fertilizer.
    Full-text · Article · Mar 2014 · Journal of Irrigation and Drainage Engineering
  • Falk Händel · Rudolf Liedl · Johann Fank · Gerhard Rock
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    ABSTRACT: Large thermal extractions and extensive implementation of groundwater heat pumps (GWHP) necessitate a validation of the sustainability of their use and possible detrimental effects on groundwater. The goal of this work is to develop a regional heat transport model (of ~13 km × 5 km) for real site conditions. This model should consider all relevant transport processes, despite the large area under investigation. The model is based on a two-dimensional, transient-calibrated groundwater flow model for the “Leibnitzer Feld” (Styria, Austria). The two-dimensional horizontal model is linked via the FEFLOW interface manager with a newly developed “Multi-Layer-Model”-tool, which reproduces thermal aquifer–atmosphere interaction. Based on the regional heat transport model, scenarios are delineated for heating and cooling purposes for large GWHPs, which are appropriate for a small manufacturing business, an administrative building and 10 family homes. First of all, these have large spacing and thereafter, effects of area-covering usage of geothermal systems are evaluated for five administrative buildings located in close proximity to one another (200–350 m) and also for a large number of smaller heat extractions (each representing a one family house system). Modeled spatial and temporal temperature effects on the shallow aquifer are discussed. It was possible to present a simulation of realistic heating and cooling scenarios. This simulation may be introduced into practice once some further simplifications to the system are made. Locally limited heat plumes (max. length: 625 m) were observed for the manufacturing business. Any thermal effects coming from the geothermal systems were shown to be temporally stable. As such, no distinct trend of reduced annual temperatures could be observed.
    No preview · Article · Dec 2013 · Environmental Earth Sciences
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    ABSTRACT: We present a novel approach for the numerical simulation of the gelation of silicate solutions under density-dependent flow conditions. The method utilizes an auxiliary, not density-dependent solute that is subject to a linear decay function to provide temporal information that is used to describe the viscosity change of the fluid. By comparing the modeling results to experimental data, we are able to simulate the behavior and the gelation process of the injected solute for three different compositions, including long-term stability of the gelated area, and non-gelation of low concentrations due to hydro-dynamic dispersion. This approach can also be used for other types of solutes with this gelling property and is useful in a variety of applications in geological, civil and environmental engineering.
    No preview · Article · Nov 2013 · Journal of Contaminant Hydrology
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    ABSTRACT: A groundwater model characterized by a lack of field data about hydraulic model parameters and boundary conditions combined with many observation data sets for calibration purpose was investigated concerning model uncertainty. Seven different conceptual models with a stepwise increase from 0 to 30 adjustable parameters were calibrated using PEST. Residuals, sensitivities, the Akaike information criterion (AIC and AICc), Bayesian information criterion (BIC), and Kashyap's information criterion (KIC) were calculated for a set of seven inverse calibrated models with increasing complexity. Finally, the likelihood of each model was computed. Comparing only residuals of the different conceptual models leads to an overparameterization and certainty loss in the conceptual model approach. The model employing only uncalibrated hydraulic parameters, estimated from sedimentological information, obtained the worst AIC, BIC, and KIC values. Using only sedimentological data to derive hydraulic parameters introduces a systematic error into the simulation results and cannot be recommended for generating a valuable model. For numerical investigations with high numbers of calibration data the BIC and KIC select as optimal a simpler model than the AIC. The model with 15 adjusted parameters was evaluated by AIC as the best option and obtained a likelihood of 98%. The AIC disregards the potential model structure error and the selection of the KIC is, therefore, more appropriate. Sensitivities to piezometric heads were highest for the model with only five adjustable parameters and sensitivity coefficients were directly influenced by the changes in extracted groundwater volumes.
    No preview · Article · Jun 2013 · Ground Water
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    ABSTRACT: Conduit Flow Process (CFP) couples a pipe flow model to MODFLOW-2005. In this hybrid model the karst aquifer is conceptualized as a dual flow system consisting of highly conductive conduits and a less conductive porous/fissured rock matrix. The code is partly based on the hybrid model Carbonate Aquifer Void Evolution (CAVE). The existing CFP functionality is enhanced by processes and boundary conditions to facilitate the practical applicability for karst characterization and management. Modifications comprise (A) enhancements to flow routines and (B) addition of heat and solute transport. Enhancements to flow routines are intended to improve CFP capabilities for water abstraction from karst aquifers, e.g., large scale hydraulic tests. These applications require one to consider fast-responding storage in connection with the conduit network. Hence, conduit-associated drainable storage was implemented in CFP. Beyond this, specific boundary conditions were added, namely a constraint for the fixed head boundary that limits in- or outflow from karst conduits by a user-defined threshold. It is demonstrated that the enhanced CFP flow routines can qualitatively reproduce water abstraction scenarios. Implementation of mass and heat transport routines allows one to apply CFP to tracer test analysis. Existing heat and solute transport routines from CAVE were updated, enhanced, and converted to CFP. With this, CFP computes convective heat transport with matrix conduction for laminar and turbulent flow. A conduit interacts with the matrix via a thermal boundary layer and matrix conduction is considered by a localized 1D radial approach perpendicular to the conduits. Solute transport considers advection and dispersion for laminar and turbulent flow. Additionally, solutes in conduits can interact with the surrounding rock, resulting in matrix diffusion. The correct implementation of heat and solute transport is demonstrated by schematic model studies. Likewise, these model studies illustrate the sensitivity of different transport processes useful for future field application.
    No preview · Conference Paper · Apr 2013
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    ABSTRACT: Thermal management of aquifers requires knowledge on interactions and heat transport processes not only on a local but also on a more regional scale. Therefore, prediction of temperature developments due to thermal use and other anthropogenic impacts necessitate the use of large scale numerical models based on field temperature measurements. This contribution presents different modelling strategies for the thermal management of shallow rural and urban groundwater bodies. Depending on the settings and the relevant management topics different boundary conditions have to be considered. Whereas, thermal regimes within rural groundwater bodies primarily are governed by natural boundaries and the interaction with the atmosphere, in urban areas also the influences of urbanization and heated subsurface constructions have to be considered. Therefore, the setup of modelling tools as basis for the thermal management of groundwater bodies in different settings requires different interaction processes to be focused on. The study is illustrated by selected examples of a rural groundwater body located in the "Leibnitzer Feld" (Austria) and an urban groundwater body located in the city of Basel (Switzerland). The two case studies differ in their respective hydro-geological setting, above all in the vertical extents of the saturated and unsaturated zone. Therefore, specific modelling approaches are used to focus on a reliable description of the main governing impacts. The regional models evaluate current and future thermal use of the groundwater bodies and highlight the advantages arising from a regional view of heat transport processes.
    Full-text · Article · Apr 2013

Publication Stats

2k Citations
147.30 Total Impact Points

Institutions

  • 1996-2015
    • Technische Universität Dresden
      • Institut für Grundwasserwirtschaft
      Dresden, Saxony, Germany
  • 1996-2009
    • University of Tuebingen
      • Group of Applied Geosciences
      Tübingen, Baden-Württemberg, Germany