Water storage and transfer in the epikarst of karstic systems during high flow periods, 2006, Aquilina L, Ladouche B, Dorfliger N,

SummaryA monitoring of spring and rain waters in the South of France during two hydrological cycles is presented. Rain waters were sampled after each precipitation event at 3 rain-gauge stations. Four karstic springs located in the same area have also been daily (high discharge events) to monthly (low flow periods) sampled. This paper focuses on compositional changes in the Cl- and Br- ions and the oxygen-18 ([delta]18O) and hydrogen ([delta]D) isotopes during the high discharge events.The responses of the different karstic systems are quite homogeneous and reflect the hydrological state of the system. The waters discharged during the major autumn and winter high discharge events originate from the epikarstic reservoir and show characteristics chemical variations related to residence in the unsaturated zone close to the surface. Their residence time in the order of 1-3 months. Correlations between the composition of the spring-water and the rainwater during three successive high discharge events during the summer of 1998 indicate that the water for high discharge event 'n' is derived from water from precipitation event 'n - 1' via a piston-type mechanism with residence time of 2 weeks.These results are interpreted as an indication of the major role of the epikarst reservoir in the karst recharge functioning. The similar behaviour of the four springs, although located in different geological contexts allows to think that the epikarst role could be more important than previously thought

Cross-formational rising groundwater at an artesian karstic basin: the Ayalon Saline Anomaly, Israel, 2006, Frumkin A, Gvirtzman H,

It is proposed that a geothermal artesian karstic system at the central part of the Yarkon-Taninim aquifer creates the 'Ayalon Saline Anomaly' (ASA), whose mechanism has been under debate for several decades. A 4-year-long detailed groundwater monitoring was carried out at 68 new shallow boreholes in the Ayalon region, accompanied by a comprehensive survey of karstic voids. Results indicate the rising of warm-brackish groundwater through highly permeable swarms of karstic shafts, serving as an outflow of the artesian geothermal system. The ASA area contains 'hot spots', where groundwater contrasts with,normal' water hundreds of meters away. The ASA temperature reaches 30 degrees C ( similar to 5 degrees C warmer than its surroundings), chloride concentration reaches 528 mg/l (50-100 mg/l in the surrounding), H2S concentration reaches 5.6 mg/l (zero all around) and pH value is 7.0 (compared with 7.8 around). Subsequently, the hydrothermal water flows laterally of at the watertable horizon through horizontal conduits, mixing with 'normal' fresh water which had circulated at shallow depth. Following rainy seasons, maximal watertable rise is observed in the ASA compared to its surroundings. Regional hydrogeology considerations suggest that the replenishment area for the ASA water is at the Samaria Mountains, east of the ASA. The water circulates to a great depth while flowing westward, and a cross-formational upward flow is then favored close the upper sub-aquifer's confinement border. (c) 2005 Elsevier Ltd All rights reserved

An assessment of the applicability of the heat pulse method toward the determination of infiltration rates in karst losing-stream reaches, 2007, Dogwiler T. , Wicks C. M. , And Jenzen E.

Quantifying the rate at which water infiltrates through sediment-choked losing stream reaches into underlying karstic systems is problematic, yet critically important. Using the one-dimensional heat pulse method, we determined the rate at which water infiltrated vertically downward through an estimated 600 m by 2 m sediment-choked losing-stream reach in the Devil’s Icebox Karst System of Central Missouri. The infiltration rate ranged from 4.9 3 1025 to 1.9 3 1026 m s21, and the calculated discharge through the reach ranged from 5.8 3 1022 to 2.3 3 1023 m3 s21. The heat pulse-derived discharges for the losing reach bracketed the median discharge measured at the outlet to the karst system. Our accuracy was in part affected by significant precipitation in the karst basin during the study period that contributed flow to the outlet from recharge areas other than the investigated losing reach. Additionally, the results could be improved by future studies that deal with identifying areas of infiltration in losing reaches and how that area varies in relation to changing flow conditions. However, the heat pulse method appears useful in providing reasonable estimates of the rate of infiltration and discharge of water through sediment-choked losing reaches.

La faune de rongeurs de Rounal 1 : révision et implications pour l’interprétation du système karstique de Saint-Remèze (Ardèche, France, 2008, Aguilar J. P. , Michaux J.

the fossil mammal bearing locality of Rounal 1: revised faunal list and its bearing for the interpretation of Saint-Remèze karstic river system (Ardeche, France). The laboratory of Palaeontology of the University of Montpellier 2 recently received the collection of rodent teeth collected and studied by Jacques Martini [2005]. The corresponding fossil mammal bearing localities are located in cavities associated to the fossil underground river system of Saint-Remèze (Ardèche). Several of Martini’s determinations relative to the Rounal 1 fauna have to be revised. New determinations drive to a younger age of the fauna and consequently its bearing on the geodynamic interpretation of the karstic system river has to be changed. Rounal 1 fauna, initially referred to the Late Miocene (Messinian), is Lower Pliocene. This new dating drives to reject the hypothesis of a deposit linked to the functioning during Messinian times of a paleoriver connected to the paleo-Ardèche. The Rounal I deposit together with the Costes Chaudes II deposit, which also belongs to the same river system, likely result from a different dynamic context of Pliocene age.

Hydrologie du Dévoluy : La Souloise, les Gillardes et le puits des Bans, 2008, Lismonde B. , Morel L. , Bertochio P.

Hydrology of Dévoluy (French PreAlps): Souloise river, Gillardes springs and puits des Bans: Dévoluy is a karstic system in the French Alps with a size of 165 km2. The basin is drained by a surface river, the Souloise, and an underground collector, reappearing at the springs of Gillardes. A cave, the puits (shaft) des Bans, situated 200 m higher, is an overflow spring of the underground system. We studied the discharge of the surface river and the spring as well as the flooding heights in the Puits des Bans during a year. The linear correlation between the spring discharge at Gillardes and the water elevation in the puits des Bans is surprising for a karstic flow. We propose a hydrologic model of two basins with a narrow link and laminar flow, of which the commmon spring is Gillardes. The obstacle is localised near the important geologic structure named Digne thrust. Some hydrologic properties are developed: hydrologic connections, hydraulic transmissivity, and storage volumes during floods.

Contribution of artificial galleries to the knowledge of karstic system behaviour in addition to natural cavern data, 2008, Garry B. , Blondel Th. , Emblanch Ch. , Sudre Ch. , Bilgot S. , Cavaillou A. , Boyer D. , Auguste M.

The study of karstic systems is mainly based on hydrodynamic and hydrochemical data collected at system inlets (rainfall) and outlets (springs). Indeed, some complementary data base coming from speleological and hydrogeological explorations of natural cavities exist. However, they are not completely representative of all the types of flows. These kinds of flow which have a large part in general hydrodynamics of a system are already the result of a structured organization of karst due to complex phenomena of limestone dissolution. Artificial galleries have the advantage to be easily accessible. Moreover, they cut randomly flows which are much less structured or not. Both types of information seem to be complementary in order to understand a karstic aquifer. In this paper, we focus on the hydrochemical and hydrodynamic study of unstructured flows of the Low-Noise Underground Laboratory of Rustrel- Pays d’Apt (LSBB), a former military site with 3,4 km of buried galleries.

Contribution of artificial galleries to the knowledge of karstic system behaviour in addition to natural cavern data, 2008, Garry B. , Blondel Th. , Emblanch Ch. , Sudre Ch. , Bilgot S. , Cavaillou A. , Boyer D. , Auguste M

The study of karstic systems is mainly based on hydrodynamic and hydrochemical data collected at system inlets (rainfall) and outlets (springs). Indeed, some complementary data base coming from speleological and hydrogeological explorations of natural cavities exist. However, they are not completely representative of all the types of flows. These kinds of flow which have a large part in general hydrodynamics of a system are already the result of a structured organization of karst due to complex phenomena of limestone dissolution.
Artificial galleries have the advantage to be easily accessible. Moreover, they cut randomly flows which are much less structured or not. Both types of information seem to be complementary in order to understand a karstic aquifer.
In this paper, we focus on the hydrochemical and hydrodynamic study of unstructured flows of the Low-Noise Underground Laboratory of Rustrel- Pays d’Apt (LSBB), a former military site with 3,4 km of buried galleries.

The dripwaters and speleothems of Poole's Cavern: a review of recent and ongoing research, 2010, Hartland, Adam, Ian J Fairchild, Jamie R Lead, David Dominguezvillar, Andy Baker, John Gunn, Mohammed Baalousha And Yon Junam

This paper describes aspects of the geochemical conditions prevalent in the dripwaters of Poole's Cavern, Buxton, UK. We examine what makes Poole's Cavern both highly unusual, and also, extremely useful for understanding geochemical processes, both in hyperalkaline, and natural karstic systems. We review the findings of ongoing research into the colloidal and dissolved organic species and associated trace elements in hyperalkaline dripwaters and show that the composition and appearance of poached-egg stalagmites can largely be explained by the high pH conditions prevalent in their parent waters and the carbon dioxide sources in cave air.

The study of Karstic aquifers geodetic measurements in Bus de la Genziana station − Cansiglio plateau (northeastern Italy), 2011, Barbara Grillo Carla Braitenberg Roberto Devoti & Ildikò, Nagy

We propose an interdisciplinary study of karstic aquifers using tiltmeters and GPS observations. The study region is located in northeastern Italy, in the seismic area of the Cansiglio Plateau. The Zöllner type Marussi tiltmeters are installed in a natural cavity (Bus de la Genziana) that is part of an interesting karstic area of particular hydrogeologic importance. The Livenza river forms from a number of springs at the foothills of the karstic massif and flows through the Friuli-Veneto plain into the Adriatic Sea. Comparing the tiltmeter signal recorded at the Genziana station with the local pluviometrical series and the hydrometric series of the Livenza river, a clear correlation is recognized. Moreover, the data of a permanent GPS station located on the southern slopes of the Cansiglio Massif (CANV) show also a clear correspondence with the water runoff. Here we present the hydrologic induced deformations as observed by tiltmeter and GPS. After heavy rain events we record rapid deformations both by tiltmeters and GPS corresponding to the rainfall duration. In the following days a slow geodetic motion recovers the accumulated deformation with a distinctive pattern both in tilt and GPS data, which correlates with the runoff of the karstic aquifer. The purpose of this research is to open a new multidisciplinary frontier between geodetic and karstic systems studies to improve the knowledge of the underground fluid flow circulation in karstic areas. Furthermore a better characterization of the hydrologic effects on GPS and tilt observations will have the benefit that these signals can be corrected when the focus of the study is to recover the tectonic deformation.

The use of a karstic cave system in a study of active tectonics: fault displacements recorded at Driny Cave, Male Karpaty Mts (Slovakia), 2011, Briestensky Milos, Stemberk Josef, Michalik Jozef, Bella Pavel, Rowberry Matt D.

This paper reports on a study of active tectonics undertaken in the intracratonic setting of central Europe in the junction zone between Eastern Alps and Western Carpathians. The study site is focused on the karstic system of Driny Cave in the Male Karpaty Mts, Slovakia. A range of geological, geomorphological, and in situ displacement data are presented. From previous geological mapping and our slickenside analyses, it is clear that the cave system has developed along significant fault structures. Further geomorphological investigations pointed towards ongoing faulting and block movements. For example, a number of slope failures can be seen on the hillsides above the cave and numerous fresh speleothem breaks can be observed within the cave. To test this hypothesis, three optical-mechanical crack gauges were installed in 2005. These gauges confirmed and quantified the ongoing movements. The NNE-SSW striking fault has recorded a strike-slip trend of 0.1 mm/year and a normal fault trend of 0.03 mm/year. The NW-SE striking fault has recorded a strike-slip trend of 0.04 mm/year. In addition, it has been possible to define their precise kinematics. Moreover, different strike-slip mechanisms along two transverse fault systems point to a horizontal stress field orientation. These results confirm the existence of active tectonic structures within central Europe. It is considered that the methodology described here can also be applied in other intracratonic settings where karstic cave systems are present. This would help define potentially seismogenic areas where unambiguous evidence for active faulting is lacking.

GHOST-ROCK STRUCTURES AND THE NATURE OF AZÉ CAVES, 2011, Quinif, Yves

Because of the presence of wall and roof cupolas and other microforms indicative of differential weathering, we first of all considered the genesis of the Azé caves, following the usual concept of karstogenesis, as a phreatic formation. A second stage is a vadose evolution associated with the underground river. But the time relationship between the two caves presents a problem because
the deposits in the Aiglons gallery demonstrate a river evolution during the last glaciation. Today, we know that many karstic systems begin their genesis by a process of ghost-rock formation. The discovery of the “Galerie de Chauffailles” proves this origin, because the speleologists have removed not river sediments, but the residual alterite in a “pseudoendokarst”. Some stratigraphic sequences of
the bedrock in the prehistoric gallery can be seen as residual alterite: the “ghost-rock” in the “Galerie de Chauffailles”. The genesis of the Azé caves began by a ghost-rock phase giving a pseudoendokarstic system consisting of weathered interconnected cavities. This residual alterite is made up of less minus soluble minerals like silica cherts, clay minerals and sparitic calcite. It is very fragile and porous. The second stage consists in the mechanical removal of the residual alterite by an underground river. A very interesting characteristic of the Azé cave is that we can study the contact between the river sediments of the second stage and the residual alterit  of the first stage.

A cause de la présence de formes pariétales de type coupoles et microformes de corrosion différentielle, on a longtemps considéré la genèse de grottes telles celles d’Azé comme issue de conditions phréatiques, dans le contexte de la karstogenèse par évacuation totale. Une deuxième étape comprend une évolution vadose de type fluviatile. Mais les relations temporelles entre les deux grottes d’Azé posent un problème. Les dépôts fluviatiles de la Galerie des Aiglons démontrent qu’il a existé une circulation fluviatile durant la dernière glaciation. Cette constatation permet d’envisager une genèse de type fantôme de roche, pour laquelle cette question d’évolution ne constitue plus un problème. La découverte de la Galerie de Chauffailles prouve ce type de spéléogenèse. En effet, la désobstruction de cette galerie ne s’est pas faite dans les sédiments fluviatiles, mais pour une bonne part en retirant l’altérite résiduelle demeurée dans un pseudoendokarst. La genèse de la Grotte d’Azé commence ainsi par une altération in situ générant un système de pseudoendokarsts consistant en volumes altérés interconnectés. L’altérite résiduelle est composée des minéraux insolubles ou moins solubles comme les chailles, la calcite sparitique, les minéraux argileux. Ce milieu est fragile et très poreux. La
seconde étape évolutive est l’érosion mécanique partielle de cette altérite résiduelle par les rivières souterraines. Une caractéristique très intéressante de la grotte d’Azé est qu’il y est possible d’étudier le contact entre l’altérite résiduelle et les sédiments fluviatiles.

Environmental Hydrogeological Study of Louros watershed, Epirus, Greece, 2012, Konstantina Katsanou

The present study aims to describe and characterize the Ionian zone karst formation concerning the karstification grade of carbonate formations and the development of aquifers, through the hydrogeological study of Louros River drainage basin, considering hydrological, hydrogeological and meteorological data, as well as major, trace element, rare earth element and isotope concentrations. It also aims to investigate basic karst properties such as storativity, homogeneity, infiltration coefficients and the parameters of the Louros basin hydrological balance.

To accomplish this aim daily discharge measurements obtained from Public Power Corporation at the Pantanassa station during the years 1956-1957, along with random discharge measurements from 15 springs along the basin performed by IGME between the years 1979-1989, daily meteorological data from 18 stations and 18 sets of potentiometric surface measurements from 38 sites were compiled. Additionally, chemical analyses on major and trace element concentrations of 42 rock samples and of five sets of water samples from 64 sampling sites, along with fourteen sets of successive periods in order to study the seasonal variation in the chemical composition of 11 springs and REE concentrations of 116 water samples. Moreover isotope ratios from 129 rain samples collected at five different altitudes, 331 samples of surface and groundwater samples, radon measurements on 21 groundwater samples and microbiological on 46 samples of surface and groundwater were evaluated. Daily runoff and random spring discharge missing data were completed applying the SAC-SMA and MODKARST simulation algorithms and the values of these parameters for the duration of the research (2008-2010) were predicted. The accuracy of the predicted values was tested applying statistical methods but also against observed values from in situ measurements performed during the same period (2008-2010).

Louros River drainage basin is located at the southern part of Epirus and covers an area of 953 km². It is elongated and together with the adjacent basin of River Arachthos they constitute the major hydrographic systems discharging in the Amvrakikos Gulf. The main morphological features of the basin are elongated mountain ranges and narrow valleys, which are the result of tectonic and other geological processes mainly controlled by the limestone-“flysch” alternations. The length of the river’s major channel, which is parallel to the major folding direction (NNW-SSE), is 73.5 km. The mountainous part of the hydrogeological basin covers an area of 400 km² and its endpoint was set at the Pantanassa station, where discharge measurements are performed. The underground limits of the basin coincides with the surface one, defined by the flysch outcrops at the western margin of the Ziros-Zalongo fault zone to the South, the application of isotope determinations and hydraulic load distribution maps at the North and East.

Geologically, Louros River drainage basin is composed of the Ionian zone formations. Triassic evaporites constitute the base of the zone overlain by a thick sequence of carbonate and clastic sedimentary rocks deposited from the Late Triassic to the Upper Eocene. In more detail, from base to top, the lithostratigraphical column of the zone includes dolomite and dolomitic limestone, Pantokrator limestone, Ammonitico Rosso, Posidonia Shales, Vigla limestone, Upper Senonian limestone, Palaeocene-Eocene limestone and Oligocene “flysch”. The major tectonic features of the regions are folds with their axes trending SW-NE at the northern part and NNW-SSE to NNE-SSW southern of the Mousiotitsa-Episkopiko-Petrovouni fault system and the strike-slip fault systems of Ziros and Petousi.

The evaluation of the daily meteorological data revealed that December is the most humid month of the year followed by January, whereas July and August are the driest months. Approximately 40-45% of the annual precipitation is distributed during the winter time and 30% during autumn. The mean annual precipitation ranges from 897.4 to 2051.8 mm and the precipitation altitude relationship suggests an increased precipitation with altitude at a rate of 84 mm/100 m. The maximum temperature is recorded during August and it may reach 40°C and the minimum during January. The temperature variation with the altitude is calculated at 0.61°C/100 m. The maximum solarity time is 377.8 h, recorded during July at the Arta station. December displays the highest relative humidity with a value of 84.2% recorded again at the Arta station. The highest wind velocity values are recorded at the Preveza station and similar velocities are also recorded at the Ioannina station. The real evapotranspiration in Louros drainage basin ranges between 27-39%. The potential evapotranspiration was calculated from the Ioannina station meteorological data, which are considered more representative for Louros basin, at 785.8 mm of precipitation according to Thornthwaite and at 722.0 mm according to Penman-Monteith.

According to the SAC-SMA algorithm the total discharge (surficial and underground) for the years 2008-2010 ranges between 61-73% of the total precipitation. The algorithm simulates the vertical percolation of rainwater in both unsaturated and saturated zones taking into account 15 parameters including the tension water capacity of the unsaturated zone, the maximum water storage capacity of both unsaturated and saturated zones, the water amount escaping into deeper horizons and not recorded at the basin’s outlet, the percentage of impermeable ground which is responsible for instant runoff, etc. These parameters are correlated to the hydrograph and are recalculated according to it. Two interesting aspects were pointed out from the discharge measurements and the algorithm application. The first is related to the maximum amount of free water, which can be stored at the basic flow of the karstic system, which is very high for the whole basin, reaching 1200 mm of precipitation and the second is the amount of water filtered to the deeper horizons, which reaches 0.098.

The discharge of individual karstic units was simulated applying the specialized MODKARST code. The code, which transforms precipitation to discharge resolving mathematical equations of non-linear flow using the mass and energy balance, successfully completed the time series of available data of spring discharge measurements for the period between the years 2008-2010.

Additionally, a number of useful parameters including spring recharge, delay period between precipitation and discharge, the storage capacity of the discharge area were also calculated by the MODKARST code. These data enabled the calculation of the annual infiltration coefficient for each one of the 15 springs and for the whole basin; the latter was found to range between 38-50% of annual precipitation. The total supply area was estimated approximately at 395 km², which is consistent with the area of Louros hydrogeological basin calculated from hydrogeological data.

The 18 sets of water table measurements, each one corresponding to a different period, revealed that the aquifers of the intermediate part of Louros basin, which are developed in Quaternary alluvial sediments, are laterally connected to the carbonate formations of the individual karstic spring units, forming a common aquifer with a common water table.

Groundwater flow follows a general N-S direction from the topographic highs to the coastal area with local minor shifts to NE-SW and NW-SE directions. The artificial lake at the position of the Public Power Corporation’s Dam at the south of the region is directly connected to the aquifer and plays an important role in water-level variation. The water table contours display a higher gradient to the southern part due to the decreased hydraulic conductivity of the limestones close to Agios Georgios village. The decreased hydraulic conductivity is believed to be the reason for the development of the homonymous spring although the hydraulic load distributions suggest the extension of the aquifer to the south and a relation to the water level in Ziros Lake, boreholes and the Priala springs. The hydraulic gradient in the broader region ranges between 4-16‰. The absolute water level variation between dry and humid season ranges from 2 m at the South to 15-20 m to the North with an average of 9 m.

The hydrological balance of Louros River mountainous basin according to the aforementioned data is calculated as follows: The total precipitation between the years 2008-2010 ranged between 5.67E+08-9.8E+08 m³ and the discharge at Pantanassa site between 3.47E+08-6.83E+08 m³. The real evapotransiration ranged between 29-39% of the precipitation. The total discharge (runoff and groundwater) accounted for 61-73% of the precipitation, whereas the basic flow due to the percolation ranged between 34-38%. Considering a mean water level variation of 9 m, between the dry and humid season, the water amount constituting the local storage is 2025Ε+07 m³.

Statistical evaluation on spring discharge data and the recession curves analysis revealed three distinct levels with diverse karstic weathering along Louros basin coinciding to the upper, intermediate and low flow of Louros River, respectively. The developed karstic units are generally complex but simple individual units develop as well. The response of spring discharge to the stored water amounts is immediate but with relatively large duration suggesting the storage of large quantities of water and a well-developed system of karstic conduits, which however has not yet met its complete evolution. The karst spring’s units are homogeneous and each one is distinguished from different recession coefficients.

The three levels of flow are also distinguished from the duration curves, which point to individual units upstream, complex units receiving and transmitting water to the adjacent ones in the middle part and complex that only receive water from the upper. This distinguishment is also enhanced by the groundwater’s major ion concentrations, which reveal Ca-HCO₃ water-type upstream, along with the isotopic composition at the same part. The prevalent Ca-HCO₃-Cl-SO₄ water-type in the middle part, the Na-Ca-Cl-SO₄ water-type downstream and isotope variation confirms this distinguishment. Moreover, REE variation is also consistent with the three levels. The assumption of relatively large stored water reserves, which contribute to analogous “memory” of spring karstic units, as pointed out by autocorreletion functions is enhanced from SAC-SMA algorithm which premises an increased capacity at the lower zone of basic flow, as well as from the hydrochemical and isotopic composition of groundwater. Monitoring of the seasonal variation in groundwater composition revealed minor variations of hydrochemical parameters and remarkably stable isotopic composition. Both aspects can be explained by the existence of a considerable water body acting as a retarder to external changes.

The crosscorrelation functions suggest a well-developed karstic system, which however has not yet reached its complete maturity also confirmed from field observations. The same conclusion is extracted from the homogeneous evolution at the interval of each karstic unit as demonstrated from recession curves on spring hydrographs.

The results from hydrochemical analyses also revealed the effect of evaporitic minerals and phosphate-rich rocks in groundwater composition and confirmed the hydraulic relationships between surface and groundwater.

The study of the isotopic composition also contributed to exclude the potential connection between the Ioannina and Louros basins, confirmed the meteoric origin of groundwater and revealed the effect of seawater in the chemical composition of few sampling sites.

The microbiological research only revealed minor incidents of contamination and significant attenuation of microorganisms during periods of high discharge.

A method for the stochastic modeling of karstic systems accounting for geophysical data: an example of application in the region of Tulum, Yucatan Peninsula (Mexico), 2012, Vuilleumier C. , Borghi A. , Renard P. , Ottowitz D. , Schiller A. , Supper R. , Cornaton F.

The eastern coast of the Yucatan Peninsula, Mexico, contains one of the most developed karst systems in the world. This natural wonder is undergoing increasing pollution threat due to rapid economic development in the region of Tulum, together with a lack of wastewater treatment facilities. A preliminary numerical model has been developed to assess the vulnerability of the resource. Maps of explored caves have been completed using data from two airborne geophysical campaigns. These electromagnetic measurements allow for the mapping of unexplored karstic conduits. The completion of the network map is achieved through a stochastic pseudo-genetic karst simulator, previously developed but adapted as part of this study to account for the geophysical data. Together with the cave mapping by speleologists, the simulated networks are integrated into the finite-element flow-model mesh as pipe networks where turbulent flow is modeled. The calibration of the karstic network parameters (density, radius of the conduits) is conducted through a comparison with measured piezometric levels. Although the proposed model shows great uncertainty, it reproduces realistically the heterogeneous flow of the aquifer. Simulated velocities in conduits are greater than 1 cm s⁻¹, suggesting that the reinjection of Tulum wastewater constitutes a pollution risk for the nearby ecosystems.

Formation and development of a karstic system below and above sea level in Messinian Mani Peninsula (S. Greece), 2012, Papadopoulou Vrynioti Kyriaki, Kampolis Isidoros

At the western shores of Messinian Mani Peninsula in South Greece, the composite, integrated karstic system of ‘‘Selinitsa’’ cave and ‘‘Drakos’’ underground river is developed above and below sea-level respectively, in the medium-bedded limestones of the Mani geotectonic unit. The formation and the development of these caves started, most likely, during Middle Pleistocene. Initially, these caves were terrestrial and developed separately. They were connected probably during Holocene through a fi ssure. The development of this united karstic system is controlled by tectonics. ‘‘Selinitsa’’ cave is older than ‘‘Drakos’’. The sequential base levels of karstifi cation demonstrate the continuous sea-level changes during Pleistocene and Holocene, induced by the relative tectonic activity. This united karstic system is characterized by ‘incomplete linkage’ to the sea.

Effects of sinuosity factor on hydrodynamic parameters estimation in karst systems: a dye tracer experiment from the Beyyayla Sinkhole (Eskişehir, Turkey), 2013, Aydin H. , Ekmekci M. , Soylu M. E.

The sinuosity factor (SF) is a critical value in karst systems in terms of estimating their hydrodynamic parameters including groundwater velocity, coefficient of dispersion, etc., through dye tracer experiments. SF has been used in a number of different dye tracer experiments in karstic systems to estimate a representative flow path. While knowing SF is crucially important in the estimation of hydrodynamic parameters, its calculation is associated with significant uncertainty due to the complexity of subsurface karstic features. And yet, only a few studies have discussed its uncertainties, which might lead some errors in estimation of hydrodynamic parameters from dye tracer experiment. In this study, dye tracer experiments were conducted in two consecutive years (2003 and 2004) representing low and high flow conditions in the Beyyayla sinkhole (Eskişehir, Turkey) where the flow path is well known. Uranine was used in experiments as a tracer and QTRACER computer program was used to determine the hydrodynamic properties of the Beyyayla karst system as well as to gain insights into the effects of SF from dye tracer experiments on estimated parameters. The results showed that the breakthrough curve follows a unimodal and a bimodal distribution in low and high flow conditions, respectively. These different distributions stem from the water transport mechanisms, where velocities were calculated as 58.2 and 93.6 m h−1 during low and high flow conditions observed in a spring emerging from the south side of the studied system. The results also show that the coefficient of dispersion, Reynolds number, and Peclet number increased and longitudinal dispersivity decreased with the higher flow rate. Furthermore, the estimated parameters did not vary with either the flow conditions or the tracer transit time, but they have shown some variations with SF. When SF was increased by 50 %, a change in these parameters was obtained in the range of 50–125 %.