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Speleology in Kazakhstan

Shakalov on 04 Jul, 2018
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

New publications on hypogene speleogenesis

Klimchouk on 26 Mar, 2012
Dear Colleagues, This is to draw your attention to several recent publications added to KarstBase, relevant to hypogenic karst/speleogenesis: Corrosion of limestone tablets in sulfidic ground-water: measurements and speleogenetic implications Galdenzi,

The deepest terrestrial animal

Klimchouk on 23 Feb, 2012
A recent publication of Spanish researchers describes the biology of Krubera Cave, including the deepest terrestrial animal ever found: Jordana, Rafael; Baquero, Enrique; Reboleira, Sofía and Sendra, Alberto. ...

Caves - landscapes without light

akop on 05 Feb, 2012
Exhibition dedicated to caves is taking place in the Vienna Natural History Museum   The exhibition at the Natural History Museum presents the surprising variety of caves and cave formations such as stalactites and various crystals. ...

Did you know?

That confined is a modifier which describes a condition in which the potentiometric surface is above the top of the aquifer [22]. synonymous with artesian.?

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
See all featured articles
Featured articles from other Geoscience Journals
Karst environment, Culver D.C.
Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs, Bontognali, Tomaso R.R.; D’Angeli Ilenia M.; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano M.; Gonzales, Esteban R. G.; De Waele, Jo
Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
Microbial mediation of complex subterranean mineral structures, Tirato, Nicola; Torriano, Stefano F.F;, Monteux, Sylvain; Sauro, Francesco; De Waele, Jo; Lavagna, Maria Luisa; D’Angeli, Ilenia Maria; Chailloux, Daniel; Renda, Michel; Eglinton, Timothy I.; Bontognali, Tomaso Renzo Rezio
Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria), Briestensky, Milos; Rowberry, Matt; Stemberk, Josef; Stefanov, Petar; Vozar, Jozef; Sebela, Stanka; Petro, Lubomir; Bella, Pavel; Gaal, Ludovit; Ormukov, Cholponbek;
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Your search for time series (Keyword) returned 60 results for the whole karstbase:
Showing 31 to 45 of 60
Ice caves as an indicator of winter climate evolution: a case study from the Jura Mountains, 2005, Luetscher Marc, Jeannin Pierre Yves, Haeberli Wilfried,
Subsurface ice fillings were first described in the Jura Mountains at the end of the sixteenth century. In order to assess the impact of climate change on low-altitude cave ice a detailed inventory has been drawn up and more than 50 objects have been identified. Comparisons between older cave maps, photographic documents and present-day observations outline a negative trend in ice mass balances, a trend that increased at the end of the 1980s. As most of these ice caves act as cold air traps, this negative mass balance is mainly attributed to higher winter temperatures and to reduced snow precipitation at low altitudes. The equilibrium line altitude of ice caves is believed to have increased several hundred metres between AD 1978 and 2004. Photographic comparisons and proxy records in some of the caves studied provide evidence of a rapid mass turnover. Ice ages range between less than a few decades and a millennium. Climatic records in these ice fillings will therefore present only short time series compared with other cave sediments. However, indications of former ice fillings have been found in different caves of the Jura Mountains and outline their potential role as palaeoclimatic markers

Microclimatic characterization of caves and analysis of the antropic impact for touristic use. PhD thesis , 2005, Ferná, Ndezcorté, S A.

The conservation and protection of caves requires suitable management tools that are based on a detailed knowledge of the environmental parameters of karst areas. The main tool for karst management is the definition and delimitation of protected areas and, in the case of tourist caves, an estimation of the visitor carrying capacity. This doctoral thesis deals with the most important methodologies related to the monitoring of cave microclimates, and focuses on show caves. The use of a great quantity of environmental data derived from different caves in southern Spain has required the use of several statistical techniques to meet the objective of simplifying and revaluating this environmental information. It is expected that the main focus of interest of this research thesis to managers of these geo-heritage sites lies in the possibility of incorporating the results of cave environmental monitoring into an integrated model of management, which also contemplates socio-economic aspects. The analysis of microclimates in each of the caves under study is dealt with in different ways depending on the type of data recorded within each one of them. Caves such as the 'Cueva del Agua' and 'Cueva de las Ventanas' are typified by the spatiotemporal behavior of the main microclimatic variables, such as the temperature and carbon dioxide content of the air. This information about the 'zero state' of the cave is complemented by an analysis of the infiltration processes and a study of the air-mass exchange phenomena. In the Sorbas karst, the design and installation of an intelligent environmental control system inside one of the potential tourist caves (System Covadura) allowed an extensive time series database to be assembled, which together with information about the spatial microclimate, comprises the base knowledge of the initial state of the cave before any tourist activities are authorized. The Giant Geode of Pulpí (Almería, Spain) represents an exceptional case with characteristics that are distinct from show caves as defined in the strictest sense of the term. The uniqueness of this site in terms of its fragility and dimension, together with the imminent need to adopt measures for its protection, resulted in the execution of an exhaustive microclimatic study in order to evaluate the possibility of opening the geode to tourists.


Microclimatic characterization of caves and analysis of the antropic impact for touristic use, PhD Thesis , 2005, Ferná, Ndezcorté, S A

The conservation and protection of caves requires suitable management tools that are based on a detailed knowledge of the environmental parameters of karst areas. The main tool for karst management is the definition and delimitation of protected areas and, in the case of tourist caves, an estimation of the visitor carrying capacity. This doctoral thesis deals with the most important methodologies related to the monitoring of cave microclimates, and focuses on show caves. The use of a great quantity of environmental data derived from different caves in southern Spain has required the use of several statistical techniques to meet the objective of simplifying and revaluating this environmental information. It is expected that the main focus of interest of this research thesis to managers of these geo-heritage sites lies in the possibility of incorporating the results of cave environmental monitoring into an integrated model of management, which also contemplates socio-economic aspects. The analysis of microclimates in each of the caves under study is dealt with in different ways depending on the type of data recorded within each one of them. Caves such as the 'Cueva del Agua' and 'Cueva de las Ventanas' are typified by the spatiotemporal behavior of the main microclimatic variables, such as the temperature and carbon dioxide content of the air. This information about the 'zero state' of the cave is complemented by an analysis of the infiltration processes and a study of the air-mass exchange phenomena. In the Sorbas karst, the design and installation of an intelligent environmental control system inside one of the potential tourist caves (System Covadura) allowed an extensive time series database to be assembled, which together with information about the spatial microclimate, comprises the base knowledge of the initial state of the cave before any tourist activities are authorized. The Giant Geode of Pulpí (Almería, Spain) represents an exceptional case with characteristics that are distinct from show caves as defined in the strictest sense of the term. The uniqueness of this site in terms of its fragility and dimension, together with the imminent need to adopt measures for its protection, resulted in the execution of an exhaustive microclimatic study in order to evaluate the possibility of opening the geode to tourists.


Modification and preservation of environmental signals in speleothems, 2006, Fairchild Ij, Smith Cl, Baker A, Fuller L, Spotl C, Mattey D, Mcdermott F, Eimp,
Speleothems are primarily studied in order to generate archives of climatic change and results have led to significant advances in identifying and dating major shifts in the climate system. However, the climatological meaning of many speleothem records cannot be interpreted unequivocally, this is particularly so for more subtle shifts and shorter time periods, but the use of multiple proxies and improving understanding of formation mechanisms offers a clear way forward. An explicit description of speleothem records as time series draws attention to the nature and importance of the signal filtering processes by which the weather, the seasons, and longer-term climatic and other environmental fluctuations become encoded in speleothems. We distinguish five sources of variation that influence speleothem geochemistry, i.e. atmospheric, vegetation/soil, karstic aquifer, primary speleothem crystal growth and secondary alteration, and give specific examples of their influence. The direct role of climate diminishes progressively through these five factors. We identify and review a number of processes identified in recent and current work that bear significantly on the conventional interpretation of speleothem records, for example: (1) speleothem geochemistry can vary seasonally and hence a research need is to establish the proportion of growth attributable to different seasons and whether this varies over time; (2) whereas there has traditionally been a focus on monthly mean delta O-18 data of atmospheric moisture, current work emphasizes the importance of understanding the synoptic processes that lead to characteristic isotope signals, since changing relative abundance of different weather types might control their variation on the longer-term; (3) the ecosystem and soil zone overlying the cave fundamentally imprint the carbon and trace element signals and can show characteristic variations with time; (4) new modelling on aquifer plumbing allows quantification of the effects of aquifer mixing; (5) recent work has emphasized the importance and seasonal variability Of CO2-degassing leading to calcite precipitation upflow of a depositional site on carbon isotope and trace element composition of speleothems; (6) although much is known about the chemical partitioning between water and stalagmites, variability in relation to crystal growth mechanisms and kinetics is a research frontier; (7) aragonite is susceptible to conversion to calcite with major loss of chemical information, but the controls on the rate of this process are obscure. Analytical factors are critical in generating high-resolution speleothem records. A variety of methods of trace element analysis is available, but standardization is a common problem with the most rapid methods. New stable isotope data on Irish stalagmite CC3 compares rapid laser-ablation techniques with the conventional analysis of micromilled powders and ion microprobe methods. A high degree of comparability between techniques for delta O-18 is found on the millimeter to centimeter scale, but a previously described high-amplitude oxygen isotope excursion around 8.3 ka is identified as an analytical artefact related to fractionation of the laser-analysis associated with sample cracking. High-frequency variability of not less than 0.5 parts per thousand may be an inherent feature of speleothem delta O-18 records. (c) 2005 Elsevier B.V. All rights reserved

Springflow hydrographs: Eogenetic vs. telogenetic karst, 2006, Florea Lj, Vacher Hl,
Matrix permeability in the range of 10(-11) to 10(-14) m(2) characterizes eogenetic karst, where limestones have not been deeply buried. In contrast, limestones of postburial, telogenetic karst have matrix permeabilities on the order of 10(-15) to 10(-20) m(2). Is this difference in matrix permeability paralleled by a difference in the behavior of springs draining eogenetic and telogenetic karst? Log Q/Q(min) flow duration curves from 11 eogenetic-karst springs in Florida and 12 telogenetic-karst springs in Missouri, Kentucky, and Switzerland, plot in different fields because of the disparate slopes of the curves. The substantially lower flow variability in eogenetic-karst springs, which results in the steeper slopes of their flow duration curves, also makes for a strong contrast in patterns (e.g., 'flashiness') between the eogenetic-karst and telogenetic-karst spring hydrographs. With respect to both spring hydrographs and the flow duration curves derived from them, the eogenetic-karst springs of Florida are more like basalt springs of Idaho than the telogenetic-karst springs of the study. From time-series analyses on discharge records for 31 springs and published time-series results for 28 additional sites spanning 11 countries, we conclude that (1) the ratio of maximum to mean (Q(max)/Q(mean)) discharge is less in springs of eogenetic karst than springs of telogenetic karst; (2) aquifer inertia (system memory) is larger in eogenetic karst; (3) eogenetic-karst aquifers take longer to respond to input signals; and (4) high-frequency events affect discharge less in eogenetic karst. All four of these results are consistent with the hypothesis that accessible storage is larger in eogenetic-karst aquifers than in telogenetic-karst aquifers

Nonlinear kernel functions for karst aquifers, 2006, Jukic Damir, Icjukic Vesna,
SummaryThis paper presents a form of kernel function for karst aquifers derived from the time-invariant and non-anticipatory Volterra series. The shape of the kernel function depends on the current value of an index of antecedent recharge that is considered as an indicator of groundwater levels and vadose zone saturation. The proposed nonlinear form preserves specific characteristics of instantaneous unit hydrographs. By using analogies with the conceptual model of nonlinear reservoir, it is shown that the second component of the kernel function characterizes the prevailing type of groundwater flow. If the second component is positive, the free-surface flow is dominant, whereas the negative value indicates that the flow under pressure prevails. Groundwater recharge rates are calculated by using a groundwater recharge model based on the Palmer's soil-moisture balance method. The values of parameters of the groundwater recharge model are estimated by the spectral method which is modified to avoid the assumption about exponential forms of autocorrelation functions of input and output time series. This paper analyzes also the practical applicability of nonlinear kernels for the preliminary characterization of karst aquifers and the karst springs discharge modeling. The results of applications on the springs zones of the rivers Krka and Krcic are in accordance with previous assumptions that the Main Krka Spring is an ascending karst spring which aquifer is situated deeply inside the karst underground, whereas the Main Krcic Spring function as a descending karst spring

A multicell karstic aquifer model with alternative flow equations, 2006, Rozos Evangelos, Koutsoyiannis Demetris,
A multicell groundwater model was constructed to investigate the potential improvement in the modelling of karstic aquifers by using a mixed equation suitable for both the free surface and pressure flow conditions in karstic conduits. To estimate the model parameters the shuffled complex evolution (SCE) optimisation method was used. This ensured a fast and objective model calibration. The model was applied to two real-world karstic aquifers and it became clear that in case of absence of water level measurements, the use of the mixed equation did not improved the performance. In cases where both spring discharge and water level measurements were available, the use of the mixed equation proved to be advantageous in reproducing the features of the observed time series especially of the water level

Long-term changes in the cave atmosphere air temperature as a result of periodic heliophysical processes, 2006, Stoeva Penka, Stoev Alexey, Kiskinova Nadya,
Climatic trends connected with short- and long-period variations of the solar activity occur as a reaction even in such conservative media as the air volumes of karst caves. The yearly mean air temperatures in the zone of constant temperatures of four show caves in Bulgaria were studied for a period of 36 years (1968-2003). The examination was made by everyday noon measurements in Ledenika, Saeva dupka, Snezhanka and Uhlovitsa cave. The caves are situated at different altitudes and geographic latitude. Seasonal fluctuations of the yearly mean air temperature in the ZCT of the explored caves have been identified by Fourier analysis. The same analysis has been applied for the Sunspot number and Apmax indices, which are representatives of the solar and geomagnetic activity, for the same period of data available. Autocorrelograms have been used for examination of the seasonal patterns of the air temperatures in the ZCT in every cave and in Sunspot number and Apmax indices. Cross-spectrum analysis has been applied for retrieving the correlations between air ZCT temperatures in the caves and solar and geomagnetic activity. It has been found that the correlation between ZCT temperature time series and sunspot number is better than that between the cave air temperature and Apmax indices. It has been found that is rather connected with the first peak in geomagnetic activity, which is associated with transient solar activity, i.e., coronal mass ejections (CMEs) than with the second one, which is higher and connected with the recurrent high speed streams from coronal holes (Webb, D.F., 2002. CMEs and the solar cycle variation in their geoeffectiveness. In: Wilson, A. (Ed.), Proceedings of the SOHO 11 Symposium on From Solar Min to Max: Half a Solar Cycle with SOHO, 11-15 March 2002, Davos, Switzerland. ESA Publications Division, Noordwijk, 2002, ISBN 92-9092-818-2, pp. 409-419). This work can contribute to studying the mechanisms of atmospheric circulation changes and calibration of long-period climatic data read from cave speleothems and deposits

Long-term changes in the cave atmosphere air temperature as a result of periodic heliophysical processes, 2006, Stoeva P. , . Stoev A. , Kiskinovab N. .

Climatic trends connected with short- and long-period variations of the solar activity occur as a reaction even in such conservative media as the air volumes of karst caves. The yearly mean air temperatures in the zone of constant temperatures of four show caves in Bulgaria were studied for a period of 36 years (1968–2003). The examination was made by everyday noon measurements in Ledenika, Saeva dupka, Snezhanka and Uhlovitsa cave. The caves are situated at different altitudes and geographic latitude. Seasonal fluctuations of the yearly mean air temperature in the ZCT of the explored caves have been identified by Fourier analysis. The same analysis has been applied for the Sunspot number and Apmax indices, which are representatives of the solar and geomagnetic activity, for the same period of data available. Autocorrelograms have been used for examination of the seasonal patterns of the air temperatures in the ZCT in every cave and in Sunspot number and Apmax indices. Cross-spectrum analysis has been applied for retrieving the correlations between air ZCT temperatures in the caves and solar and geomagnetic activity. It has been found that the correlation between ZCT temperature time series and sunspot number is better than that between the cave air temperature and Apmax indices. It has been found that View the MathML source is rather connected with the first peak in geomagnetic activity, which is associated with transient solar activity, i.e., coronal mass ejections (CMEs) than with the second one, which is higher and connected with the recurrent high speed streams from coronal holes (Webb, D.F., 2002. CMEs and the solar cycle variation in their geoeffectiveness. In: Wilson, A. (Ed.), Proceedings of the SOHO 11 Symposium on From Solar Min to Max: Half a Solar Cycle with SOHO, 11–15 March 2002, Davos, Switzerland. ESA Publications Division, Noordwijk, 2002, ISBN 92-9092-818-2, pp. 409–419). This work can contribute to studying the mechanisms of atmospheric circulation changes and calibration of long-period climatic data read from cave speleothems and deposits.


Climatic differences and similarities between Indian and East Asian Monsoon regions of China over the last millennium: a perspective based mainly on stalagmite records, 2007, Tan Ming
Cave sediments, especially stalagmites, have been providing absolute dated climate records that can extend from the present to over 500,000 years ago. Based on the reconstructed temperature time series, a comprehensive overview of the climatic differences and similarities between the Indian and the East Asian Monsoon regions of China over the last millennium is presented. Evidence from accurately dated and high-resolution records including stalagmites, ice cores and tree rings show that there was a Medieval Warm Period (around 1000 to 1400 AD) in north and east China where climate is dominated by the East Asian monsoon; whilst no such interval is evident in the records including stalagmites and ice cores from southwest China where climate is dominated by the Indian monsoon. However, both regions underwent a significant cooling during the Little Ice Age (around the mid 1500s to the 1800s). The result achieved here may allow a possibility of distinguishing the boundary between Indian monsoon and East Asian monsoon regions over the last millennium with increase of climate records, especially stalagmites that are mostly suitable for accurate U/Th dating and/or lamina counting.

Climatic similarities and differences between Northeast and Southwest China over the last millennium: a perspective based on stalagmite records., 2007, Tan, Ming
Cave sediments, especially stalagmites, have been providing absolute dated climate records that can extend from the present to over 500,000 years ago. Based on the reconstructed temperature time series, a comprehensive overview of the climatic differences and similarities between the Indian and the East Asian Monsoon regions of China over the last millennium is presented. Evidence from accurately dated and high-resolution records including stalagmites, ice cores and tree rings show that there was a Medieval Warm Period (around 1000 to 1400 AD) in north and east China where climate is dominated by the East Asian monsoon; whilst no such interval is evident in the records including stalagmites and ice cores from southwest China where climate is dominated by the Indian monsoon. However, both regions underwent a significant cooling during the Little Ice Age (around the mid 1500s to the 1800s). The result achieved here may allow a possibility of distinguishing the boundary between Indian monsoon and East Asian monsoon regions over the last millennium with increase of climate records, especially stalagmites that are mostly suitable for accurate U/Th dating and/or lamina counting.

Modelling of the functioning of karst aquifers with a reservoir model: Application to Fontaine de Vaucluse (South of France), 2007, Fleury Perrine Plagnes Valé, Rie Bakalowicz Michel
This work deals with a rainfall-discharge model applied to a well known karst aquifer. A new approach is developed in order to minimize the fitting parameters: here, some of the model parameters do not result from a simple fitting, as it was the case with earlier models, i.e., some of them were assessed from the hydrograph analysis. The conceptual model of the functioning is based on a production function based on a simple calculation of effective rainfall and a transfer function consisting of two reservoirs. A slow discharge reservoir transfers the low flow and a rapid discharge reservoir feeds the high flow. The model has three fitted parameters plus one for its initialisation. Three parameters are deduced from the hydrograph analysis over the entire time series. For example, the recession coefficient of the slow discharge reservoir is determined from the hydrodynamic analysis of the recession [Mangin, A., 1975. Contribution à l?étude hydrodynamique des aquifères karstiques. 3ème partie. Constitution et fonctionnement des aquifères karstiques. Annales de Spéléologie, 30 (1), 210?124]. This model was tested over a ten years period on the Fontaine de Vaucluse French karst system. The first hydrological year is used for fitting the model; the nine other cycles validate the modelling. The good quality of the model is proved by the Nash criterion of 92.3% on the validation period. Moreover, the simulation results were validated by a statistical analysis of measured and simulated time series. The model successfully simulates both the high and low flow at the same time. Also it estimates the water volumes available in the different parts of the aquifer and it proposes a management tool capable of predicting the evolution of the discharge in different climate conditions.

Climatic differences and similarities between Indian and East Asian Monsoon regions of China over the last millennium: a perspective based mainly on stalagmite records, 2007, Tan, M.

Cave sediments, especially stalagmites, have been providing absolute dated climate records that can extend from the present to over 500,000 years ago. Based on the reconstructed temperature time series, a comprehensive overview of the climatic differences and similarities between the Indian and the East Asian Monsoon regions of China over the last millennium is presented. Evidence from accurately dated and high-resolution records including stalagmites, ice cores and tree rings show that there was a “Medieval Warm Period” (around 1000 to 1400 AD) in north and east China where climate is dominated by the East Asian monsoon; whilst no such interval is evident in the records including stalagmites and ice cores from southwest China where climate is dominated by the Indian monsoon. However, both regions underwent a significant cooling during the Little Ice Age (around the mid 1500s to the 1800s). The result achieved here may allow a possibility of distinguishing the boundary between Indian monsoon and East Asian monsoon regions over the last millennium with increase of climate records, especially stalagmites that are mostly suitable for accurate U/Th dating and/or lamina counting.


Interactions hydrodynamiques surface/souterrain en milieu karstique [Surface water/Groundwater hydrodynamic interactions in karst watersheds], PhD Thesis, 2008, Baillycomte, Vincent

Ce travail de these s’inscrit dans la problematique generale de la caracterisation de l’alea inondation. Plus precisement, cette etude cherche a caracteriser l’influence des eaux souterraines sur la genese et la propagation des crues en surface dans les cas d’un bassin versant a forte composante karstique. Le site experimental du bassin versant du Coulazou, riviere temporaire qui traverse le massif karstique du Causse d’Aumelas a l’Ouest de Montpellier a ete retenu pour etudier de maniere approfondie les interactions entre les ecoulements de surface et les ecoulements souterrains en situation de crue.

L’etude hydrodynamique de ce systeme karst/riviere s’appuie sur un dispositif experimental adapte a l’observation des phenomenes hydrologiques (pluie, ruissellement) et hydrogeologiques (piezometrie en forage et dans les drains karstiques, suivi hydrodynamique des exutoires du systeme) tres rapides et tres intenses. La dynamique de ces ecoulements est liee au contexte climatique Mediterraneen mais aussi aux structures de drainage en surface et en souterrain qui permettent un transfert et un transit tres rapide des eaux au sein du systeme karst/riviere.

Une description hydrodynamique classique est completee par une approche fonctionnelle des echanges karst/riviere dans le but de mieux comprendre le fonctionnement hydrodynamique d’un tel systeme et de mettre en avant des indicateurs utilisables dans une demarche de modelisation des echanges surface/souterrain. Un premier modele est presente dans la derniere partie de ce document.

**********

This work aims at assessing the flooding hazard. More precisely, the study focuses on the influence of groundwater on the genesis and propagation of surface flows in the case of a highly karstified watershed. The experimental site of the Coulazou River, a temporary River which crosses the karstified formation of the Causse d’Aumelas (western Montpellier) has been selected to study hydrodynamic interactions between surface flows and groundwater flows during flood.

The hydrodynamic study of this karst/River system is based on a suitable experimental monitoring of both fast and intense hydrological (rain, runoff) and hydrogeological (water level in wells and karst drains, discharge measurements at the main outlets of the system) phenomenon. The specific hydrological response of this watershed is due to the Mediterranean climate but also to surface and underground drainage structures which allow very fast water flows within the karst/river system.

A common hydrodynamic description is followed by a functional approach of karst/river exchanges in order (i) to better understand the hydrodynamic behaviour of such a system and (ii) to highlight some indicators that can be used in a modelling approach. A first conceptual model of surface water/groundwater exchanges in karst terranes is presented in the latter part of the manuscript.
 


HYDROLOGIC CONNECTIONS AND DYNAMICS OF WATER MOVEMENT IN THE CLASSICAL KARST (KRAS) AQUIFER: EVIDENCE FROM FREQUENT CHEMICAL AND STABLE ISOTOPE SAMPLING, 2008, Doctor, D. H.

A review of past research on the hydrogeology of the Classical Karst (Kras) region and new information obtained from a two- year study using environmental tracers are presented in this paper. The main problems addressed are 1) the sources of water to the Kras aquifer resurgence zone—including the famous Timavo springs—under changing flow regimes; 2) a quantification of the storage volumes of the karst massif corresponding to flow regimes defined by hydrograph recessions of the Timavo springs; and 3) changing dynamics between deep phreatic conduit flow and shallow phreatic and epiphreatic storage within the aquifer resurgence zone as determined through changes in chemical and isotopic composition at springs and wells. Particular focus was placed on addressing the long-standing question of the influence of the Soča River on the ground waters of the aquifer resurgence zone. The results indicate that the alluvial aquifer supplied by the sinking of the Soča River on the northwestern edge of the massif contributes approximately 75% of the mean annual outflow to the smaller springs of the aquifer resurgence zone, and as much as 53% to the mean annual outflow of the Timavo springs. As a whole, the Soča River is estimated to contribute 56% of the average outflow of the Kras aquifer resurgence. The proportions of Soča River water increase under drier conditions, and decrease under wetter conditions. Time series analysis of oxygen stable isotope records indicate that the transit time of Soča River water to the Timavo springs, Sardos spring, and well B-4 is on the order of 1-2 months, depending on hydrological conditions. The total baseflow storage of the Timavo springs is estimated to be 518 million m3, and represents 88.5% of the storage capacity estimated for all flow regimes of the springs. The ratio of baseflow storage volume to the average annual volume discharged at the Timavo springs is 0.54. The Reka River sinking in Slovenia supplies substantial allogenic recharge to the aquifer; however, its influence on the northwest resurgence zone is limited to the Timavo springs, and is only a significant component of the spring discharge under flood conditions for relatively brief periods (several days to weeks). Sustainability of the trans-boundary aquifer of the Kras will benefit from maintaining high water quality in the Soča River, as well as focused water tracing experiments within the epiphreatic zone of the aquifer to better delineate the recharge zone and to identify sources of potential contamination to the Brestovica water supply well.


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