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Andreas Fuchs - One of the best experts on this subject based on the ideXlab platform.
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distribution patterns of groundwater communities across Aquifer Types in south western germany
Freshwater Biology, 2009Co-Authors: Hans Jürgen Hahn, Andreas FuchsAbstract:Summary 1. Classification of groundwater habitats and communities at different spatial scales is emphasised as a basic requirement for the implementation of groundwater ecology into legislation. Such a classification would also facilitate prediction of groundwater biodiversity, abundance and community structure, but is not currently available. 2. To identify the factors influencing the distribution of stygofauna at the landscape scale, the groundwater fauna of Baden–Wurttemberg in South-western Germany was sampled from November 2001 to December 2002. A total of 304 boreholes were sampled twice with a phreatic net. Boreholes were originally selected to represent the full range of geographic, geological and hydrographic variation within the sampling area. However, bores in porous Aquifers were overrepresented because the monitoring networks that could be used in this study were originally designed for hydrogeological purposes. 3. In total, 105 taxa (including 60 stygobionts) were found. Most of the stygobionts were rare, with 52% of them occurring in less than 1% of the boreholes. Stygobiotic taxonomic richness in a region or so-called geological unit was directly correlated with the number of bores sampled. Species richness accumulation curves indicated that the real taxonomic richness of Baden–Wurttemberg is considerably higher than the recorded number of 60 stygobiotic taxa. This finding is in accordance with studies from other regions and suggests that groundwater biodiversity generally is strongly underestimated, probably resulting mainly from huge heterogeneity of groundwater systems and reliance on broad-scale hydrological monitoring networks. 4. To identify regional distribution patterns, the sampling area was separated into regional geological units, each comprising all Aquifers of identical geology in a particular region (size: hundred to several thousand square kilometres). Distribution patterns of the aquatic subterranean fauna (including non-stygobionts) were found to be influenced to some degree by the geographical position of the bores, and to a large extent by hydrogeological Aquifer type rather than by affiliation of Aquifers to a given geological unit. Four Types of Aquifers could be distinguished: Compact Aquifers (aquitards) with reduced pore spaces, and porous, fractured and karstic Aquifers. 5. Communities of porous and karstic Aquifers were found to be more similar to each other than the communities of compact and fractured Aquifers. Therefore, for the purpose of recording groundwater biodiversity and defining undisturbed groundwater habitats, we suggest focusing more strongly than in the past on Aquifer hydraulic conductivity and, in particular, on compact and fractured Aquifers.
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Distribution patterns of groundwater communities across Aquifer Types in south‐western Germany
Freshwater Biology, 2009Co-Authors: Hans Jürgen Hahn, Andreas FuchsAbstract:Summary 1. Classification of groundwater habitats and communities at different spatial scales is emphasised as a basic requirement for the implementation of groundwater ecology into legislation. Such a classification would also facilitate prediction of groundwater biodiversity, abundance and community structure, but is not currently available. 2. To identify the factors influencing the distribution of stygofauna at the landscape scale, the groundwater fauna of Baden–Wurttemberg in South-western Germany was sampled from November 2001 to December 2002. A total of 304 boreholes were sampled twice with a phreatic net. Boreholes were originally selected to represent the full range of geographic, geological and hydrographic variation within the sampling area. However, bores in porous Aquifers were overrepresented because the monitoring networks that could be used in this study were originally designed for hydrogeological purposes. 3. In total, 105 taxa (including 60 stygobionts) were found. Most of the stygobionts were rare, with 52% of them occurring in less than 1% of the boreholes. Stygobiotic taxonomic richness in a region or so-called geological unit was directly correlated with the number of bores sampled. Species richness accumulation curves indicated that the real taxonomic richness of Baden–Wurttemberg is considerably higher than the recorded number of 60 stygobiotic taxa. This finding is in accordance with studies from other regions and suggests that groundwater biodiversity generally is strongly underestimated, probably resulting mainly from huge heterogeneity of groundwater systems and reliance on broad-scale hydrological monitoring networks. 4. To identify regional distribution patterns, the sampling area was separated into regional geological units, each comprising all Aquifers of identical geology in a particular region (size: hundred to several thousand square kilometres). Distribution patterns of the aquatic subterranean fauna (including non-stygobionts) were found to be influenced to some degree by the geographical position of the bores, and to a large extent by hydrogeological Aquifer type rather than by affiliation of Aquifers to a given geological unit. Four Types of Aquifers could be distinguished: Compact Aquifers (aquitards) with reduced pore spaces, and porous, fractured and karstic Aquifers. 5. Communities of porous and karstic Aquifers were found to be more similar to each other than the communities of compact and fractured Aquifers. Therefore, for the purpose of recording groundwater biodiversity and defining undisturbed groundwater habitats, we suggest focusing more strongly than in the past on Aquifer hydraulic conductivity and, in particular, on compact and fractured Aquifers.
Hans Jürgen Hahn - One of the best experts on this subject based on the ideXlab platform.
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distribution patterns of groundwater communities across Aquifer Types in south western germany
Freshwater Biology, 2009Co-Authors: Hans Jürgen Hahn, Andreas FuchsAbstract:Summary 1. Classification of groundwater habitats and communities at different spatial scales is emphasised as a basic requirement for the implementation of groundwater ecology into legislation. Such a classification would also facilitate prediction of groundwater biodiversity, abundance and community structure, but is not currently available. 2. To identify the factors influencing the distribution of stygofauna at the landscape scale, the groundwater fauna of Baden–Wurttemberg in South-western Germany was sampled from November 2001 to December 2002. A total of 304 boreholes were sampled twice with a phreatic net. Boreholes were originally selected to represent the full range of geographic, geological and hydrographic variation within the sampling area. However, bores in porous Aquifers were overrepresented because the monitoring networks that could be used in this study were originally designed for hydrogeological purposes. 3. In total, 105 taxa (including 60 stygobionts) were found. Most of the stygobionts were rare, with 52% of them occurring in less than 1% of the boreholes. Stygobiotic taxonomic richness in a region or so-called geological unit was directly correlated with the number of bores sampled. Species richness accumulation curves indicated that the real taxonomic richness of Baden–Wurttemberg is considerably higher than the recorded number of 60 stygobiotic taxa. This finding is in accordance with studies from other regions and suggests that groundwater biodiversity generally is strongly underestimated, probably resulting mainly from huge heterogeneity of groundwater systems and reliance on broad-scale hydrological monitoring networks. 4. To identify regional distribution patterns, the sampling area was separated into regional geological units, each comprising all Aquifers of identical geology in a particular region (size: hundred to several thousand square kilometres). Distribution patterns of the aquatic subterranean fauna (including non-stygobionts) were found to be influenced to some degree by the geographical position of the bores, and to a large extent by hydrogeological Aquifer type rather than by affiliation of Aquifers to a given geological unit. Four Types of Aquifers could be distinguished: Compact Aquifers (aquitards) with reduced pore spaces, and porous, fractured and karstic Aquifers. 5. Communities of porous and karstic Aquifers were found to be more similar to each other than the communities of compact and fractured Aquifers. Therefore, for the purpose of recording groundwater biodiversity and defining undisturbed groundwater habitats, we suggest focusing more strongly than in the past on Aquifer hydraulic conductivity and, in particular, on compact and fractured Aquifers.
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Distribution patterns of groundwater communities across Aquifer Types in south‐western Germany
Freshwater Biology, 2009Co-Authors: Hans Jürgen Hahn, Andreas FuchsAbstract:Summary 1. Classification of groundwater habitats and communities at different spatial scales is emphasised as a basic requirement for the implementation of groundwater ecology into legislation. Such a classification would also facilitate prediction of groundwater biodiversity, abundance and community structure, but is not currently available. 2. To identify the factors influencing the distribution of stygofauna at the landscape scale, the groundwater fauna of Baden–Wurttemberg in South-western Germany was sampled from November 2001 to December 2002. A total of 304 boreholes were sampled twice with a phreatic net. Boreholes were originally selected to represent the full range of geographic, geological and hydrographic variation within the sampling area. However, bores in porous Aquifers were overrepresented because the monitoring networks that could be used in this study were originally designed for hydrogeological purposes. 3. In total, 105 taxa (including 60 stygobionts) were found. Most of the stygobionts were rare, with 52% of them occurring in less than 1% of the boreholes. Stygobiotic taxonomic richness in a region or so-called geological unit was directly correlated with the number of bores sampled. Species richness accumulation curves indicated that the real taxonomic richness of Baden–Wurttemberg is considerably higher than the recorded number of 60 stygobiotic taxa. This finding is in accordance with studies from other regions and suggests that groundwater biodiversity generally is strongly underestimated, probably resulting mainly from huge heterogeneity of groundwater systems and reliance on broad-scale hydrological monitoring networks. 4. To identify regional distribution patterns, the sampling area was separated into regional geological units, each comprising all Aquifers of identical geology in a particular region (size: hundred to several thousand square kilometres). Distribution patterns of the aquatic subterranean fauna (including non-stygobionts) were found to be influenced to some degree by the geographical position of the bores, and to a large extent by hydrogeological Aquifer type rather than by affiliation of Aquifers to a given geological unit. Four Types of Aquifers could be distinguished: Compact Aquifers (aquitards) with reduced pore spaces, and porous, fractured and karstic Aquifers. 5. Communities of porous and karstic Aquifers were found to be more similar to each other than the communities of compact and fractured Aquifers. Therefore, for the purpose of recording groundwater biodiversity and defining undisturbed groundwater habitats, we suggest focusing more strongly than in the past on Aquifer hydraulic conductivity and, in particular, on compact and fractured Aquifers.
A. Ufuk Sahin - One of the best experts on this subject based on the ideXlab platform.
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Identification of Aquifer and well parameters from step-drawdown tests
Hydrogeology Journal, 2010Co-Authors: Cem B. Avci, Emin Ciftci, A. Ufuk SahinAbstract:Une nouvelle technique d’analyse est proposée pour interpréter les données d’essais de descente par palier en régime transitoire. La méthode proposée est basée sur la dérivée du rabattement en fonction du temps pendant toute la durée du pompage d’essai pour éliminer les termes de perte de charge indépendants du temps. La fonction dérivée est ensuite intégrée pour obtenir le rabattement sous la forme d’une fonction continue du temps. Les paramètres de perte de charge sont alors obtenus avec une meilleure précision une fois identifié le comportement de l’aquifère. La méthode proposée est applicable pour analyser des données obtenues non seulement sur des aquifères captifs idéaux, mais aussi sur d’autres Types d’aquifères (i.e. libres) et des aquifères non idéaux (i.e. hétérogènes). La technique a été testée avec des données synthétiques et avec des données de terrain; on remarque que l’approche proposée fournit des estimations précises des paramètres de l’aquifère et des pertes de charge du puits. Les résultats de la méthode proposée ont été comparés à ceux obtenus par quelques-unes des méthodes existantes d’analyse d’essais par paliers et se sont révélés plus fiables et solides. Foi proposta uma nova técnica analítica para a interpretação de ensaios de bombagem não estacionários escalonados. O método proposto baseia-se na extracção da derivada do rebaixamento em ordem ao tempo para todo o período de ensaio de bombagem, a fim de eliminar os termos relativos às perdas no poço independentes do tempo. A função derivada é subsequentemente integrada para obter o rebaixamento no aquífero dependente do tempo, como uma função contínua. Os parâmetros de perdas no poço são então obtidos com maior precisão, uma vez identificado o comportamento do aquífero. O método proposto é aplicável à análise de dados obtidos, não só a partir de aquíferos confinados ideais, mas também de outros tipos de aquíferos (i.e. livres) e aquíferos não ideais (i.e. heterogéneos). A técnica foi ensaiada com dados gerados sinteticamente e com dados de campo; a abordagem proposta mostrou fornecer estimativas precisas dos parâmetros do aquífero e das perdas no poço. Os resultados do método proposto foram comparados com os de alguns dos métodos existentes de análise de dados de ensaios de bombagem escalonados, tendo-se verificado ser mais fiável e robusto. 本文提出了一种解译瞬时分段降深试验数据的新方法。原理是: 基于降深对整个抽水试验的时间求导, 以消掉与时间无关的井损项, 然后整理导函数, 便得到与时间相关的含水层降深连续函数。一旦含水层特性已知, 就可以更加精确地得到井损参数。这种方法不仅能应用于理想承压含水层的数据分析, 也能用于其它含水层类型 (如 非承压含水层) 以及非理想含水层 (如非均质) 的数据分析。采用合成数据与野外数据对该方法进行了测试, 表明其能够精确确定含水层及井损参数。将该方法的结果与现存的方法对分段降深试验数据的分析进行了对比, 表明该方法的分析结果更加可靠。 A new analysis technique has been proposed for interpreting transient step-drawdown test data. The proposed method is based on taking the derivative of the drawdown with respect to time for the entire pumping test period to eliminate the time-independent well-loss terms. The derivative function is subsequently integrated to obtain the time-dependent Aquifer drawdown as a continuous function. The well-loss parameters are then obtained with higher accuracy once the Aquifer behavior is identified. The proposed method is applicable for analyzing data obtained not only from ideal confined Aquifers but also from other Aquifer Types (i.e. unconfined) and non-ideal Aquifers (i.e. heterogeneous). The technique was tested for synthetically generated and field data; the proposed approach was noted to provide accurate Aquifer and well-loss parameter estimates. The results of the proposed method were compared with those of some of the existing methods for analyzing step-drawdown test data and were found to be more reliable and robust. Zamana bağlı kademeli düşüm testi verisinin yorumlanabilmesi için yeni bir analiz yöntemi önerilmiştir. Önerilen yöntem pompa testi süresince elde edilen düşüm değerlerinin zamana göre türevlenlerinin alınması ve bu şekilde zamana bağlı kuyu kayıp terimlerinin yok edilmesi esasına dayanmaktadır. Türev fonksiyonunun integrali alınarak zamana bağlı yeraltı su seviyesi düşümünün sürekli fonksiyonu elde edilir. Bu şekilde akifer davranışının belirlenmesi, kuyu kayıp parametrelerinin daha yüksek bir doğrulukla hesaplanmasına olanak sağlar. Geliştirilen yöntem sadece ideal basınçlı akiferler için değil, diğer akifer tiplerinden (serbest yüzeyli akifer gibi) veya ideal olmayan akiferlerden (heterojen akifer) elde edilen verilerin analizi için kullanılabilir. Sentetik ve gerçek verilerle test edilen yöntemin akifer ve kuyu kayıp parameterini doğru olarak verdiği görülmüştür. Önerilen yöntem ile elde edilen sonuçlar mevcut kademeli düşüm testi yöntemlerilye elde edilenlerle kıyaslanmış, yöntemin daha sağlam ve güvelir olduğu gözlemlenmiştir. Se ha propuesta una nueva técnica de análisis para interpretar de datos de ensayos transitorios de descenso de nivel escalonados. El método propuesta está basado en tomar las derivadas de la depresión con respecto al tiempo para los períodos completos de ensayos de bombeo para eliminar los términos de pérdidas del pozo temporalmente independientes. La función derivada es subsecuentemente integrada para obtener los descensos del acuífero dependiente del tiempo como una función continua. Los parámetros de pérdida del pozo son luego obtenidos con una mayor precisión una vez que es identificado el comportamiento del acuífero. El método propuesto es aplicable para analizar datos obtenidos no solamente a partir de acuíferos confinados ideales sino también para otros tipos de acuífero (por ejemplo no confinado) y acuíferos no ideales (por ejemplo heterogéneo). La técnica fue probada para datos de campo y datos generados sintéticamente; se apreció que el enfoque propuesto provee estimaciones precisas de los parámetros del acuífero y de pérdida de pozo. Los resultados del método propuesto fueron comparados con aquellos de algunos de los métodos existentes para analizar datos de ensayos de descensos escalonados y se encontró que eran más confiables y robustos.
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Identification of Aquifer and well parameters from step-drawdown tests
Hydrogeology Journal, 2010Co-Authors: Cem B. Avci, Emin Ciftci, A. Ufuk SahinAbstract:A new analysis technique has been proposed for interpreting transient step-drawdown test data. The proposed method is based on taking the derivative of the drawdown with respect to time for the entire pumping test period to eliminate the time-independent well-loss terms. The derivative function is subsequently integrated to obtain the time-dependent Aquifer drawdown as a continuous function. The well-loss parameters are then obtained with higher accuracy once the Aquifer behavior is identified. The proposed method is applicable for analyzing data obtained not only from ideal confined Aquifers but also from other Aquifer Types (i.e. unconfined) and non-ideal Aquifers (i.e. heterogeneous). The technique was tested for synthetically generated and field data; the proposed approach was noted to provide accurate Aquifer and well-loss parameter estimates. The results of the proposed method were compared with those of some of the existing methods for analyzing step-drawdown test data and were found to be more reliable and robust.
Markus Weiler - One of the best experts on this subject based on the ideXlab platform.
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Streamflow sensitivity to drought scenarios in catchments with different geology
Geophysical Research Letters, 2014Co-Authors: Michael Stoelzle, Kerstin Stahl, Andreas Morhard, Markus WeilerAbstract:Streamflow drought response depends to a large degree on groundwater recharge. To better predict and preempt streamflow droughts, the relationship between recharge deficit and streamflow response needs to be studied more systematically. We present a combined soil-vegetation-atmosphere transfer and conceptual groundwater model experiment that applies a novel set of recharge scenarios preceding drought events in humid-temperate catchments with different dominant Aquifer Types. The recharge scenarios are based on the permutation of historical time series and on modified time series matching extreme (50 year) drought events. Karstic and fractured Aquifers show short-term sensitivity to drought with an event-specific relationship between recharge and streamflow response. Porous and complex Aquifers show long-term sensitivity and a more catchment-controlled propagation of drought. The sensitivity of drought deficit and recovery time correlates with the water age distribution in baseflow, which is trackable in the groundwater model and a characteristic that should be exploited to improve streamflow drought prediction.
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Is there a superior conceptual groundwater model structure for baseflow simulation
Hydrological Processes, 2014Co-Authors: Michael Stoelzle, Markus Weiler, Kerstin Stahl, Andreas Morhard, Tobias SchuetzAbstract:Previous work has shown that streamflow response during baseflow conditions is a function of storage, but also that this functional relationship varies among seasons and catchments. Traditionally, hydrological models incorporate conceptual groundwater models consisting of linear or non-linear storage–outflow functions. Identification of the right model structure and model parameterization however is challenging. The aim of this paper is to systematically test different model structures in a set of catchments where different Aquifer Types govern baseflow generation processes. Nine different two-parameter conceptual groundwater models are applied with multi-objective calibration to transform two different groundwater recharge series derived from a soil-atmosphere-vegetation transfer model into baseflow separated from streamflow data. The relative performance differences of the model structures allow to systematically improve the understanding of baseflow generation processes and to identify most appropriate model structures for different Aquifer Types. We found more versatile and more Aquifer-specific optimal model structures and elucidate the role of interflow, flow paths, recharge regimes and partially contributing storages. Aquifer-specific recommendations of storage models were found for fractured and karstic Aquifers, whereas large storage capacities blur the identification of superior model structures for complex and porous Aquifers. A model performance matrix is presented, which highlights the joint effects of different recharge inputs, calibration criteria, model structures and Aquifer Types. The matrix is a guidance to improve groundwater model structures towards their representation of the dominant baseflow generation processes of specific Aquifer Types. Copyright © 2014 John Wiley & Sons, Ltd.
Annamária Nádor - One of the best experts on this subject based on the ideXlab platform.
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Potentials of transboundary thermal water resources in the western part of the Pannonian basin
Geothermics, 2015Co-Authors: Nina Rman, Gerhard Schubert, Nóra Gál, Daniel Marcin, Julia Weilbold, Andrej Lapanje, Dušan Rajver, Katarína Benková, Annamária NádorAbstract:Abstract In this paper we investigate hydrogeological aspects of eleven geothermal Aquifer Types in four countries in the western Pannonian basin, and their development potential. Most thermal waters outflow with temperature below 50 °C, and are used for bathing, drinking, industrial water supply, space and water heating. Geothermal electricity is produced only in Austria at a small pilot plant. Low share of direct use is coupled by small number of reinjection wells. Waste thermal water is produced at 149 user sites and by 307 objects, and shows rather low thermal efficiency of exploitation. Annual production of thermal water sums to approximately 40 million m 3 , and the Pannonian–Pontian clastic and the Mesozoic carbonate rocks form most productive and transboundary Aquifers. The innovative approach and field investigation enabled identification of potential of inactive wells which sums to 4.7 million m 3 of thermal water per year, while the legislative potential is estimated to be approximately 58.8 million m 3 per year. Since depletion of many geothermal Aquifers is already evident, such increase in production might be hydrogeologically unfeasible, at least if no improvements in utilization technology are made. In order to exploit the vast identified potentials without major investments in new production wells, we recommend optimization of exploitation and extensive implementation of reinjection wells in this transboundary region.