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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. ...

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That drainage ratio is a ratio of runoff to precipitation [16].?

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
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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 electrical conductivity (Keyword) returned 38 results for the whole karstbase:
Showing 16 to 30 of 38
Investigation of the groundwater residence time distribution in the Aladag (Kayseri-Adana, Turkey) karstic aquifer. PhD Thesis, 2004, Ozyurt, N. Nur

The Aladað karstic aquifer of Eastern Taurids Range extends between 400m and 3750m elevations and, covers an area of 1900 km2 within Adana-Kayseri-Niðde provinces. The study covers the Kapuzbaþý, Göksu shallow circulation and Yerköprü 1, Yerköprü 2 and Yerköprü 3 deep circulation springs that extend from recharge area to the Zamanti river.
The system is fed by precipitation of Mediterranean origin and total precipitation input, evapo-transpiration, net recharge and its volumetric equivalent are found to be 1113 mm, 451 mm, 879 mm and 939 106 m3. Mean annual discharges of Yerköprü 3, Yerköprü 1 and 2, Göksu and, Kapuzbaþý and Barazama springs are 449 106 m3, 82 106 m3, 299 106 m3 and 146 106 m3. Noble gas ( 20Ne, 40Ar, 84Kr) and 18O isotopes suggest recharge area elevation and temperature ranges of 1700-2100m and 2-6 oC. The helium (He) content of groundwater increases with increasing circulation depth. Year round biweekly-monthly samples’ electrical conductivity, tritium ( 3H) and 18O content reveal that Kapuzbaþý and Göksu springs and, Yerköprü 1 and Yerköprü 2 springs behave similarly among themselves.
The “CFC model ages” of the springs where, chlorofluorocarbon (CFC) contents increased from 1997 to 2002, range between 10 to 20 years and 20 to 30 years in the shallow and deep circulation parts, respectively. The 3H/3He* absolute age of groundwater from springs is around 20 +/- 2.5 years. In the computer code LUMPEDUS that was developed for unsteady state lumped parameter modeling applications, 3H, tritiogenic helium-3 ( 3He*), CFC-11, CFC-12, CFC-113, and 18O were used as environmental tracers. Serially connected plug-exponential flow model applied to all springs. All models were calibrated for observed outflux and their forecasted 3H, 3He* and 18O time series were found to be in good agreement with the observations. Mean residence times found by models are in agreement with 3H/3He* ages. According to residence time distribution suggested by models, most of the discharges comprise recharges that occurred within last 20 to 30 years. Sixty per cent of discharge comprises recharges of the last 3 to 4 years. The active reservoir volumes of Yerköprü 1-2, Kapuzbaþý, Göksu and Yerköprü 3 springs are found to be 1604 106 m3, 2808 106 m3, 5728 106 m3 and 8609 106 m3 , respectively. According to well established linear relationship between reservoir volumes and discharge elevations, an active volume increases 50 106 m3 per 1m decrease in elevation. Cumulative active reservoir volume is found to be 18749 106 m3 at 450 m elevation where Yerköprü 3 spring is located. Uppermost elevation of active reservoir is located at 836m. Groundwater’s velocity ranges from 2.09 m/day to 5.57 m/day and the corresponding hydraulic conductivities for different reservoirs are between 41.8 m/day and 212.2 m/day. The ordering of hydraulic conductivity among springs ( > > > ) seems to be related to their time of formation. Based on an assumption of 1500m of maximum hydraulic head at the recharge area, the effective porosity of the system is estimated to be 0.86 per cent.


Vulnerability mapping in the recharge area of the Korentan spring, Slovenia, 2004, Petrič, Metka, Š, Ebela Stanka

Karst aquifers are very vulnerable to pollution due to well developed system of karst channels and fissures which enable fast groundwater flow and also fast transport of pollutants. An expert bases for their protection are vulnerability maps. Different methods for the construction of these maps were developed, and to assess the vulnerability of the recharge area of the Korentan spring near Postojna the EPIK method was used. In this method, which was many times successfully tested on karst, the degree of vulnerabilty is defined on the basis of four parameters: developement of the epikarst, effectiveness of the protective cover, infiltration conditions, and development of the karst network. For the assessment of individual parameters different research methods were used, such as detailed structural-lithological and geomorphological mapping, and combined analysis of hydraulic and physico-chemical responses of the spring to recharge events. Final result is the vulnerability map, which defines the areas of very high, high and moderate vulnerability within the recharge area of the Korentan spring and can be used to set up the protection zones.


Der Karst auf der Erzwies, Bad Hofgastein (Salzburg)., 2005, Hfer, G(iorgio).
The Erzwies (ore meadow) is located in the upper part of the Angertal near Bad Hofgastein at an altitude of 2200 to 2500 m. The geology is dominated by 10 to 20 m thick marbles, surrounded and underlain by gneiss (Zentralgneis). Numerous karst phenomena are bound to a system of NNE-SSW- and E-W-striking joints. Quartzitic schists are locally folded into the marbles, resulting in different types of polje, springs, caves, shafts and sinkholes. The runoff of creeks and springs was studied and temperature, electrical conductivity and pH were measured. Karst waters have conductivity values of more than 100 S/cm and pH values slightly above 8, while the conductivity values of surface waters and springs in gneiss are 60 to 90 S/cm with pH values of less than 8. A cave system called Silberpfennighhle (2586/10) appears too large given the short time of its formation and missing signs of tectonic control. A model is proposed whereby the interactions of fluids derived from oxidation of ore minerals resulted in subsurface dissolution and karst cavity formation.[Geologie, Tektonik, Erkundung der Gewsser hinsichtlich Schttung, Leitfhigkeit, pH-Wert und Temperatur; Quellhhle in der Erzwies (2586/9), Silberpfennighhle (2586/10); Hhlengenese]

Cave air control on dripwater geochemistry, Obir Caves (Austria): Implications for speleothem deposition in dynamically ventilated caves, 2005, Spotl C. , Fairchild I. J. , Tooth A. F. ,
There are very few process studies that demonstrate the annual variation in cave environments depositing speleothems. Accordingly, we initiated a monitoring program at the Obir Caves, an Austrian dripstone cave system characterized by a seasonally changing air flow that results in a predictable pattern of high pCO(2), during summer and low pCO(2), in winter. Although similar seasonal changes in Soil pCO(2) occur, they are not directly connected with the changes in the subsurface since the dripwaters are fed from a well-mixed source showing little seasonal variation. Cold season flushing by relatively CO2-poor air enhances degassing of CO2 in the cave and leads to a high degree of supersaturation of dripwater with regard to calcite. Forced calcite deposition during the cold season also gives rise to a pronounced pattern of synchronous seasonal variations in electrical conductivity, alkalinity, pH, Ca and delta(13)C(DIC) which parallel variations recorded in delta(13)C(cave air). Chemical components unaffected by calcite precipitation (e.g., delta D,delta(18)O,SiO2,SO4) lack a seasonal signal attesting to a long residence in the karst aquifer. Modeling shows that degassing of CO2 from seepage waters results in kinetically-enhanced C isotopic fractionation, which contrasts with the equilibrium degassing shown from the Soreq cave in Israel. The Obir Caves may serve as a case example of a dripstone cave whose seepage waters (and speleothems) show intra-annual geochemical variability that is primarily due to chemical modification of the groundwater by a dynamic, bidirectional subsurface air circulation. Copyright (c) 2005 Elsevier Ltd

Der Karst auf der Erzwies, Bad Hofgastein (Salzburg), 2005, Hfer, G.
The Erzwies (ore meadow) is located in the upper part of the Angertal near Bad Hofgastein at an altitude of 2200 to 2500 m. The geology is dominated by 10 to 20 m thick marbles, surrounded and underlain by gneiss (Zentralgneis). Numerous karst phenomena are bound to a system of NNE-SSW- and E-W-striking joints. Quartzitic schists are locally folded into the marbles, resulting in different types of polje, springs, caves, shafts and sinkholes. The runoff of creeks and springs was studied and temperature, electrical conductivity and pH were measured. Karst waters have conductivity values of more than 100 S/cm and pH values slightly above 8, while the conductivity values of surface waters and springs in gneiss are 60 to 90 S/cm with pH values of less than 8. A cave system called Silberpfennighhle (2586/10) appears too large given the short time of its formation and missing signs of tectonic control. A model is proposed whereby the interactions of fluids derived from oxidation of ore minerals resulted in subsurface dissolution and karst cavity formation.

Hoga island, Sulawesi, Indonesia: geomorphology and groundwater resources of a small tropical carbonate island, 2006, Dykes A. P. , Gunn J.
This paper provides the first report of the geomorphology and hydrogeology of Hoga island, a small tropical carbonate island in southeast Sulawesi, Indonesia, based on reconnaissance field explorations and surveys. Hoga is being developed as a specialist ecotourism destination, and a sustainable water supply is one of the important development issues. The island comprises 3.42km2 of low-lying hard, but highly karstified, coral limestone covered with dense scrub forest and coconut plantations. It displays dissolution features typical of similar tropical islands, including pit caves and flank margin caves. A freshwater aquifer exists with a water table 1.57m above MSL near the centre of the less karstified western two-thirds of the island, where surface elevations locally exceed 6m above MSL. All occurrences of potable freshwater, i.e. having electrical conductivity < 1500 mS cm-1, are also within this main part of the island. Complex hydrogeological conditions are indicated by the patterns of tidal influences on water levels in existing wells and natural dissolution holes. Using published studies and empirical relationships, it is estimated that Hoga contains a potable freshwater lens at least 2m thick (total volume c.300,000m3) and that annual recharge may exceed 500,000m3. As actual annual demand for freshwater since 2001 was < 2800m3, it is concluded that Hoga contains an aquifer that could sustain the present and likely future freshwater demands of residents and seasonal ecotourist populations, subject to satisfactory water quality assessment and management.

The hydrochemical response of cave drip waters to sub-annual and inter-annual climate variability, Wombeyan Caves, SE Australia, 2007, Mcdonald Janece , Drysdale Russell, Hill David, Chisari Robert, Won Henri
A thorough understanding of cave seepage waters is necessary to interpret geochemical variations in speleothem calcite in terms of changing surface climatic conditions at a particular site. Here we present the hydrochemistry of ten cave drip waters from a karst system in SE Australia based on up to 5.5 years of monitoring. Discharge was continuously measured at six sites and manually at the other sites. Dripwater samples were analysed for pH, electrical conductivity, cations and anions at all sites at monthly or more frequent intervals. Each drip possesses a unique chemistry, and not all drip waters responded to antecedent short-term hydrological variations. For example, the hydrochemical behaviour of three adjacent drips at a bedrock depth of 45 m was completely different to that of shallower sites, and was apparently un-related to surface hydrology throughout the investigation. Based on modelled calcite precipitation vectors, prior calcite precipitation was demonstrated at several sites but can only be linked directly to changes in surface recharge at the shallowest sites. At extremely low flow, shallow drip waters accessed a high Mg, Sr and Ba source, thought to be the overlying soil. High-frequency sample collection allows for the calculation of predicted Mg/Cacalcite and Sr/Cacalcite values, highlighting that the sites with the greatest potential to record high-resolution palaeohydrological records are those situated at shallow depth. Longer temporal-resolution palaeohydrological records may be recorded at deeper sites but longer-term monitoring is required to identify probable time scales. Inherent system non-linearities, dissolution of secondary calcite in pore spaces of the aquifer, changes in the source of trace elements, and the presence of multiple reservoirs confirm the need for the use of multiple speleothems and a multi-proxy approach to gain accurate palaeohydrological records from this site.

MANAGING AQUIFER RECHARGE (MAR): ASSESSMENT OF GROUNDWATER RESOURCES IN THE SAND, 2007, Kim Thoa Nguyen Thi, Giuseppe Arduino, Paolo Bono, Nguyen Van Giang, Phan Thi Kim Van, Bui Tran Vuong, Dinh Thi Bich Lieu, Brun Clarissa, Chiara Fiori, Fabrizio Gherardi, Francesca Zucco
Extensive geophysical, hydrological and isotopic investigations, including drilling campaigns, long term pumping tests and continuous monitoring of ground water levels in 4 monitoring wells, show that the sand dunes formation is characterized by the occurrence of an unconfined porous aquifer, of variable thickness (40 to 60 m), emerging at ground level in depressed morphological areas (20 to 30 m a.s.l.) where it forms intradune wetlands or natural reservoirs (lakes), and discharging directly to the sea through single springs (up to 200 l/s), linear springs and mostly by diffuse seepage along the shoreline (approximate discharge equal to 30 l/s per km). Hydrochemical and isotopic characterization of surface and groundwater in different periods, shows that the sand dunes aquifers, with electrical conductivity ranging from 50 to 500 μS/cm, are composed of different water types, characterized by complex mixing processes. The site chosen for the artificial recharge, where a 162 days pumping test has been carried out, proved that the use of the bank filtration technique has considerably improved the quality of water, originally highly contaminated by colibacteria. The well field developed within the present project is now capable of supplying 220 m3/day of good water quality to the Hong Phong community, recurrently affected by severe droughts. This project is part of UNESCO-IHP (International Hydrological Programme) and IMET (Italian Ministry for the Environment and Territory) Water Programme for Africa, Arid and Water Scarce zone - Viet Nam component funded by IMET. Funds for the Viet Nam project were also made available from the Vietnamese Government, and from ICSU, the International Council for Science and UNESCO Office Jakarta.

An Investigation of Meromixis in Cave Pools, Lechuguilla Cave, New Mexico, 2008, Levy D. B.
Chemical characteristics of permanent stratification in cave pools (meromixis) may provide insight into the geochemical origin and evolution of cave pool waters. The objective of this study was to test the hypothesis that some pools in Lechuguilla Cave may be subject to ectogenic meromixis, where permanent chemical stratification is induced by input of relatively saline or fresh water from an external source. However, because organic C concentrations in Lechuguilla waters are low (typically < 1 mg L-1), biogenic meromixis resulting in O2(g)-depleted subsurface waters is not expected. Four pools at various depths below ground surface (0 m) were studied: (1) Lake Chandalar (-221 m), (2) Lake of the Blue Giants (LOBG) (- 277 m), (3) Lake Margaret (- 319 m), and (4) Lake of the White Roses (LOWR) (- 439 m). Water column profiles of temperature, pH, dissolved O2(g), and electrical conductivity (EC) were collected down to a maximum depth of 13.1 m using a multi-parameter sonde. Opposite pH gradients were observed at Lake Chandalar and LOBG, where pH at the surface (0.3 m) varied by 0.20 units compared to the subsurface (> 0.9 m), and are probably the result of localized and transient atmospheric CO2(g) concentrations. At LOBG, an EC increase of 93 ?S cm-1 at the 0.9-m depth suggests meromictic conditions which are ectogenic, possibly due to surface inflow of fresh water as drips or seepage into a preexisting layer of higher salinity.

An Investigation of Meromixis in Cave Pools, Lechuguilla Cave, New Mexico., 2008, Levy, D. B.

Chemical characteristics of permanent stratification in cave pools (meromixis) may provide insight into the geochemical origin and evolution of cave pool waters. The objective of this study was to test the hypothesis that some pools in Lechuguilla Cave may be subject to ectogenic meromixis, where permanent chemical stratification is induced by input of relatively saline or fresh water from an external source. However, because organic C concentrations in Lechuguilla waters are low (typically < 1 mg L-1), biogenic meromixis resulting in O2(g)-depleted subsurface waters is not expected. Four pools at various depths below ground surface (0 m)
were studied: (1) Lake Chandalar (-221 m), (2) Lake of the Blue Giants (LOBG) (- 277 m), (3) Lake Margaret (- 319 m), and (4) Lake of the White Roses (LOWR) (- 439 m). Water column profiles of temperature, pH, dissolved O2(g), and electrical conductivity (EC) were collected down to a maximum depth of 13.1 m using a multi-parameter sonde. Opposite pH gradients were observed at Lake Chandalar and LOBG, where pH at the surface (0.3 m) varied by ±0.20 units compared to the subsurface (> 0.9 m), and are probably
the result of localized and transient atmospheric CO2(g) concentrations. At LOBG, an EC increase of 93 μS cm-1 at the 0.9-m depth suggests meromictic conditions which are ectogenic, possibly due to surface inflow of fresh water as drips or seepage into a preexisting layer of higher salinity.


An Investigation of Meromixis in Cave Pools, Lechuguilla Cave, New Mexico, 2008, Levy, D. B.

Chemical characteristics of permanent stratification in cave pools (meromixis) may provide insight into the geochemical origin and evolution of cave pool waters. The objective of this study was to test the hypothesis that some pools in Lechuguilla Cave may be subject to ectogenic meromixis, where permanent chemical stratification is induced by input of relatively saline or fresh water from an external source. However, because organic C concentrations in Lechuguilla waters are low (typically < 1 mg L-1), biogenic meromixis resulting in O2(g)-depleted subsurface waters is not expected. Four pools at various depths below ground surface (0 m) were studied: (1) Lake Chandalar (-221 m), (2) Lake of the Blue Giants (LOBG) (- 277 m), (3) Lake Margaret (- 319 m), and (4) Lake of the White Roses (LOWR) (- 439 m). Water column profiles of temperature, pH, dissolved O2(g), and electrical conductivity (EC) were collected down to a maximum depth of 13.1 m using a multi-parameter sonde. Opposite pH gradients were observed at Lake Chandalar and LOBG, where pH at the surface (0.3 m) varied by ±0.20 units compared to the subsurface (> 0.9 m), and are probably the result of localized and transient atmospheric CO2(g) concentrations. At LOBG, an EC increase of 93 μS cm-1 at the 0.9-m depth suggests meromictic conditions which are ectogenic, possibly due to surface inflow of fresh water as drips or seepage into a preexisting layer of higher salinity


On the Temporal Behavior of Karst Aquifers, zagros Region, Iran: A Geostatistical Approach, 2009, Mohammadi Z. And Field M.
A geostatistical approach was used to study temporal structures in a time series of discharge and electrical conductivity (EC) in 15 karst springs from the Zagros mountain range, Iran. Two types of temporal behaviors, a periodic structure and nugget effect, plus one or two temporal structures, were identified and interpreted. These correspond to characteristics of karst systems, such as the catchment area, percent of conduit flow, and general degree of karst development. Springs were grouped into three categories based on their ranges (e.g., residence time) obtained by variogram analysis. The first group of springs include those that present the same temporal behaviour in variograms of discharge and EC. These springs are characterized by generally constant EC with increasing discharge suggesting the existence of a large underground reservoir. The second group of springs are those with varying temporal periodic behavior in variograms of discharge and EC. Positive correlation between discharge and EC values is themain characteristic of these springs and is interpreted to result from a piston-flow system in poorly developed karst aquifers. The third group of springs includes those that exhibit different temporal behaviors when compared with the periodic and non-periodic variograms. This group exhibits a negative correlation in scatterplots of discharge versus EC values suggesting a well-developed solution-conduit system that facilitates rapid response of the karst system to precipitation events. This studys results document the role of variogram analysis in delineating temporal structures of spring behaviors by means of time series of discharge and EC. Variogram analysis can be considered as a valuable tool for hydrogeological investigations in karstic terranes.

Percolation and Particle Transport in the Unsaturated Zone of a Karst Aquifer, 2009, Pronk M. , Goldscheider N. , Zopfi J. , Zwahlen F.

Recharge and contamination of karst aquifers often occur via the unsaturated zone, but the functioning of this zone has not yet been fully understood. Therefore, irrigation and tracer experiments, along with monitoring of rainfall events, were used to examine water percolation and the transport of solutes, particles, and fecal bacteria between the land surface and a water outlet into a shallow cave. Monitored parameters included discharge, electrical conductivity, temperature, organic carbon, turbidity, particle-size distribution (PSD), fecal indicator bacteria, chloride, bromide, and uranine. Percolation following rainfall or irrigation can be subdivided into a lag phase (no response at the outlet), a piston-flow phase (release of epikarst storage water by pressure transfer), and a mixed-flow phase (increasing contribution of freshly infiltrated water), starting between 20 min and a few hours after the start of recharge event. Concerning particle and bacteria transport, results demonstrate that (1) a first turbidity signal occurs during increasing discharge due to remobilization of particles from fractures (pulse-through turbidity); (2) a second turbidity signal is caused by direct particle transfer from the soil (flow-through turbidity), often accompanied by high levels of fecal indicator bacteria, up to 17,000 Escherichia coli/100 mL; and (3) PSD allows differentiation between the two types of turbidity. A relative increase of fine particles (0.9 to 1.5 lm) coincides with microbial contamination. These findings help quantify water storage and percolation in the epikarst and better understand contaminant transport and attenuation. The use of PSD as ‘‘early-warning parameter’’ for microbial contamination in karst water is confirmed.


HYDROGEOLOGICAL STUDY OF THE MALEN?ICA KARST SPRING (SW SLOVENIA) BY MEANS OF A TIME SERIES ANALYSIS, 2010, Kova?i? G.
Time series analyses are often used for the investigation of karst aquifers, but are only rarely employed in a way of using a large number of spatially distributed time series. Furthermore, only a small number of applications employ other types of hydrological data apart from rainfall, water level and discharge. The presented study of the Malen?ica karst spring aquifer underlines the usefulness of the simultaneous auto and cross-correlation analysis of daily and hourly hydrological data sets, including discharge, water level, temperature, electrical conductivity and rainfall on a regional scale. The results of the autocorrelation analysis show that the storage capacity of the spring is moderate, but this does not indicate that the system, which is characterized by prevailing conduit porosity, is less intensively karstifed. This suggests that well karstied systems of a more complex structure can have higher memory effects than less complex systems. The results of the cross-correlation analysis show that karst springs and watercourses in the investigated area react instantly and simultaneously to rather homogeneous precipitation, yet with different intensity. In such cases a cross-correlation analysis between rainfall or ponors as inputs and springs as outputs does not provide sufficient information on the hydrogeological functioning of the system, whereas the results of a cross-correlation analysis of electrical conductivity data sets provide valuable information on its functioning and can be easily compared to those obtained by tracer tests. On the other hand, the applicability of a temperature time series in such complex karst systems is limited. A comparative analysis of the results of the time series analyses performed in successive hydrological years has proven that the selection of the hydrological year can have strong effects on the results of a time series analysis.

HYDROGEOLOGICAL FUNCTIONING OF A KARST AQUIFER DEDUCED FROM HYDROCHEMICAL COMPONENTS AND NATURAL ORGANIC TRACERS PRESENT IN SPRING WATERS. THE CASE OF YEDRA SPRING (SOUTHERN SPAIN), 2010, Mudarra M. , Andreo B.
The major chemical parameters, TOC and natural fluorescence of yedra spring, Malaga province, southern Spain were monitored from April 2008 to March 2009. The electrical conductivity and the concentrations of most major ions decreased following recharge periods. The TOC and NO3, representing tracers from the soil that infiltrate through the unsaturated zone, were found to vary inversely with the Mg2+ content, which is a natural indicator of groundwater residence time. Furthermore, a strong, direct relation was found between TOC and the natural fluorescence associated with humic and fulvic acids. Both parameters respond similarly to rainfall events, exhibiting significant increases during recharge followed by reductions during recession. This relation means that TOC mainly originates from organic acids. The results document rapid infiltration processes with a lag of less than one day following rainfall, which is typical of a karst aquifer with conduit flow, rapid drainage and limited natural regulation. The combined use of conventional hydrochemical parameters and natural organic tracers facilitates aquifer characterization and validates the vulnerability to contamination.

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