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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 LNAPL is abbreviation for light nonaqueous phase liquid. liquids falling into this category have specific gravities that are less than water (the specific gravity for water is usually taken to be one), are relatively immiscible with water, and tend to migrate downwards through the vadose and to float on top of the water table. see also lnapl; immiscible; napl.?

Checkout all 2699 terms in the KarstBase Glossary of Karst and Cave Terms

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KarstBase a bibliography database in karst and cave science.

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 coefficients (Keyword) returned 29 results for the whole karstbase:
Showing 1 to 15 of 29
Interaction between competition and predation in cave stream communities., 1975, Culver David C.
Predation by salamander larvae (Gyrinophilus porphyriticus) reduces the density of one of its prey (the isopod Asellus recurvatus) but increases the density of the other (the amphipod Crangonyx antennatus in a Virginia cave stream. This happens because predation on the isopod reduces its competitive effect on the amphipod. Both prey populations tend to occur more frequently in refugia when predators are present. In another cave where there are no prey refugia, the predator reduces the density of both species. It appears that it is easier for a predator to invade a community than to reach a stable equilibrium with the prey, if the prey have refugia, persistence of the prey system and the predator/prey system is constrained more by low population sizes than by the instability of the interaction coefficients.

Trace-element partition coefficients in the calcite-water system and their paleoclimatic significance in cave studies, 1983, Gascoyne M,
Speleothems (stalactites, stalagmites) formed in limestone caves have been found to contain much information on the timing and intensity of past climates, from analysis of their U, Th, 13C and 18O contents. Because the incorporation of certain trace elements (e.g., Mg, Mn and Zn) in calcite is known to be temperature-dependent, it may be possible to use variations in trace-metal content of fossil speleothems as an alternative paleotem-perature indicator. Using specially developed ion-exchange sampling techniques, analysis of trace-metal content of seepage water and associated fresh calcite deposits in caves in Vancouver Island and Jamaica shows that Mg is distributed between phases in a consistent manner within the temperature regimes of the caves (7[deg] and 23[deg]C, respectively). Average values of the distribution coefficient for Mg are respectively 0.017 and 0.045 at these temperatures. These results indicate that the Mg content of calcite varies directly with temperature and in a sufficiently pronounced manner that a 1[deg]C rise in depositional temperature of a speleothem containing 500 ppm Mg, at ~10[deg]C, would be seen as an increase of ~35ppm Mg -- a readily determinable shift. Other factors affecting Mg content of a speleothem are considered

Synthetic strontianite-aragonite solid-solution minerals were dissolved in CO2-saturated nonstoichiometric solutions of Sr(HCO3)2 and Ca(HCO3)2 at 25-degrees-C. The results show that none of the dissolution reactions reach thermodynamic equilibrium. Congruent dissolution in Ca(HCO3)2 solutions either attains or closely approaches stoichiometric saturation with respect to the dissolving solid. In Sr(HCO3)2 solutions the reactions usually become incongruent, precipitating a Sr-rich phase before reaching stoichiometric saturation. Dissolution of mechanical mixtures of solids approaches stoichiometric saturation with respect to the least stable solid in the mixture. Surface uptake from subsaturated bulk solutions was observed in the initial minutes of dissolution. This surficial phase is 0-10 atomic layers thick in Sr(HCO3)2 solutions and 0-4 layers thick in Ca(HCO3)2 solutions, and subsequently dissolves and/or recrystallizes, usually within 6 min of reaction. The initial transient surface precipitation (recrystallization) process is followed by congruent dissolution of the original solid which proceeds to stoichiometric saturation, or until the precipitation of a more stable Sr-rich solid. The compositions of secondary precipitates do not correspond to thermodynamic equilibrium or stoichiometric saturation states. X-ray photoelectron spectroscopy (XPS) measurements indicate the formation of solid solutions on surfaces of aragonite and strontianite single crystals immersed in Sr(HCO3)2 and Ca(HCO3)2 solutions, respectively. In Sr(HCO3)2 solutions, the XPS signal from the outer approximately 60 angstrom on aragonite indicates a composition of 16 mol% SrCO3 after only 2 min of contact, and 14-18 mol% SrCO3 after 3 weeks of contact. The strontianite surface averages approximately 22 mol% CaCO3 after 2 min of contact with Ca(HCO3)2 solution, and is 34-39 mol% CaCO3 after 3 weeks of contact. XPS analysis suggests the surface composition is zoned with somewhat greater enrichment in the outer approximately 25 angstrom (as much as 26 mol% SrCO3 on aragonite and 44 mol% CaCO3 on strontianite). The results indicate rapid formation of a solid-solution surface phase from subsaturated aqueous solutions. The surface phase continually adjusts in composition in response to changes in composition of the bulk fluid as net dissolution proceeds. Dissolution rates of the endmembers are greatly reduced in nonstoichiometric solutions relative to dissolution rates observed in stoichiometric solutions. All solids dissolve more slowly in solutions spiked with the least soluble component ((Sr(HCO3)2) than in solutions spiked with the more soluble component (Ca(HCO3)2), an effect that becomes increasingly significant as stoichiometric saturation is approached. It is proposed that the formation of a nonstoichiometric surface reactive zone significantly decreases dissolution rates

A range of hydrodynamic dispersion coefficients was estimated for fracture-fluid and combined fracture and pore-fluid now within the halocline of the limestone aquifer forming the surface of the northern Yucatan Peninsula. The coefficients are fit parameters in a model reproducing observed halocline profiles in a sinkhole and in a borehole near the northeastern coast. Fitted coefficients range from 10(-7) to 10(-4) cm(2)/sec, of which molecular diffusion, without transverse (vertical) dispersion, can account for 10(-7) to 10(-5) cm(2)/sec. The mechanical stability of the vertical density gradient in the halocline dampens transverse dispersion in pore fluids and in fracture fluids that are transitional between laminar and turbulent flow. The dampening is proportional to the ratio of the energy needed for the fluid to rise and displace a less dense fluid to the vertical component of the kinetic energy of the fluid. The ratio of these two energies is at a maximum during the initial stage of development of a halocline and decreases as the halocline widens

PC-based two-dimensional discrete Fourier transform programs for terrain analysis, 1996, Harrison J. M. , Lo C. P. ,
A two-dimensional Fast Fourier Transform (2D-FFT) program written in C language was developed for the personal computer with the specific purpose of extracting periodicities from digital elevation model (DEM) data. The program generates the individual frequency pairs, the coefficients representing the amplitudes of the cosine and sine waves, the angle the wavefront makes in the terrain, the wavelength, the power of the wave, the percent contribution the wave makes to the overall landscape, and finally the overall percentage of variance accounted for by the model. The landscape can be reconstructed based on the number of significant waveforms extracted. Generalizations on the spatial trends of the terrain therefore can be made. The Fourier analysis provides insight to the nature and complexity of the terrain. An application of the program to the karst landscape of Manati, Puerto Rico is illustrated. Copyright (C) 1996 Elsevier Science Ltd

Hydrochemographs of Berghan Karst Spring as Indicators of Aquifer Characteristics, 1997, Raeisi, E. , Karami, G.
Berghan Spring is located in the southern part of Iran, northwest of Shiraz. The catchment area of the spring consists of the southern flank of the Gar Anticline, which is made up of the karstic calcareous Sarvak Formation. There are no sinkholes or other karst landforms in the catchment area. Because of the existence of several faults, the aquifer has been brecciated and may have caused karstification to occur in most of the pores and fissures. The specific conductance, pH and water temperature were measured once every twenty days for a period of 32 months and water samples were analyzed for major anions and cations. Flow rate was measured daily during the recession, and once every three weeks during the rest of the study period. Using the WATEQF computer model, the partial pressure of carbon dioxide and the saturation index of calcite and dolomite also were estimated. Three distinct periods, the first recession, the second recession, and precipitation, were observed in the hydrograph of Berghan Spring. No considerable differences were observed between the first and second recession coefficients. Base flow constitutes 71.5%, 100% and 66.2% of total flow in the first recession period, the second recession period and the precipitation period, respectively. The variation of specific conductance, calcium and bicarbonate concentrations and calcite saturation indices are not significant during the study period, implying that aquifer characteristics control the chemical behavior of the spring. The morphology and geology of the Berghan Spring catchment area, and data from hydrographs and chemographs, show that the hydrologic system is dominantly diffuse flow. Evidence for this is shown by autogenic recharge, a brecciated aquifer, and small values and slight differences in hydrograph recession coefficients. In addition, specific conductance, calcium and bicarbonate concentrations, and water temperature did not show significant variations during the study period suggesting a diffuse flow aquifer.

The climate of the Marble Arch Caves, County Fermanagh, Northern Ireland, BSc thesis (Geography) , 1997, Perrin, D.

The Marble Arch cave is a high energy cave located in County Fermanagh, Northern Ireland. The first 500 metres of the system has been opened as a Showcave for approximately 13 years and has been visited by over half a million visitors since opening. Microclimatic investigations over a six month sampling period (31.7.96-10.1.97) found that the cave has a variable microclimate in response to, the surface climate, the caves hydrology and influences within the Showcave.
High positive correlation coefficient's were attained between the cave and surface air temperature. As distance increased into the cave correlation coefficients' decreased indicating a time lag. Air temperatures varied on both a temporal and spatial scale. Summer air temperature ranges of 2.1 °C were noted between sites within the cave, which increased to 7.1 °C during the winter season. The cave air temperature changed progressively from the entrance to the interior, decreasing in the summer and increasing in the winter months. During the summer months the mean surface air temperature (17.4°C) was greater than the cave mean air temperature (10.8°C). In the winter months the mean surface air temperature (1.9°C) was less than the cave mean air temperature (7.2°C). Site variability was generally greater during the summer months indicated by higher Coefficient of Variations.
The 'chimney effect' is noticeable in some parts of the cave as a result of surface and cave air temperature differences. Airflow within the cave changed direction in response to seasonal air temperature variations, flowing out of the cave during summer months and into the cave in the winter. Other processes such as the 'Entrainment Effect' were also evident. Airflow throughout the cave was generally weak, although in some parts of the cave was noticeable as a 'wind'.
The main river flowing through the cave was responsive to the seasonal cave air temperatures. During the summer months the water temperature once entering the cave decreases by approximately 2°C and increases by up to 7°C during the winter months. A relatively constant seasonal water temperature is maintained whilst travelling through the cave.
The largest air temperature variations occurred within the Showcave in which the presence of tourists and electrical lighting are believed to be partially responsible, the latter of which being the greater contributor. Results show that a tour of 18 people on average increased the surrounding air temperature by up to 1.3°C. The effect was reduced when a tour was moving past a point rather than remaining stationary in the same place.
Electronic lighting increased the overall air temperature throughout the Showcave. Each type of light used within the Showcave influenced the air temperature up to a metre away from the light source. Air temperature increases around the lighting was a result of the type of light used rather than the bulb wattage installed. In some cases the air temperature remained 2°C higher than the mean cave air temperature 1 metre away from the light source.

An experimental study of calcite and limestone dissolution rates as a function of pH from -1 to 3 and temperature from 25 to 80 degrees C, 1998, Alkattan M, Oelkers Eh, Dandurand Jl, Schott J,
Dissolution rates of single calcite crystals, limestones, and compressed calcite powders were determined from sample weight loss using free-drift rotating disk techniques. Experiments were performed in aqueous HCl solutions over the bulk solution pH range -1 to 3, and at temperatures of 25 degrees, 50 degrees, and 80 degrees C. Corresponding rates of the three different sample types are identical within experimental uncertainty. Interpretation of these data using equations reported by Gregory and Riddiford [Gregory, D.P., Riddiford, A.C., 1956. Transport to the surface of a rotating disc. J. Chem. Sec. London 3, 3756-3764] yields apparent rate constants and H diffusion coefficients. The logarithms of overall calcite dissolution rates (r) obtained at constant disk rotation speed are inversely proportional to the bulk solution pH, consistent with r = k(2') a(H,b), where k(2)' stands for an apparent rate constant and a(H,b) designates the hydrogen ion activity in the bulk solution, This variation of dissolution rates with pH is consistent with corresponding rates reported in the literature and the calcite dissolution mechanism reported by Wollast [Wollast, R., 1990. Rate and mechanism of dissolution of carbonates in the system CaCO3-MgCO3. In: Stumm, W. (Ed.), Aquatic Chemical Kinetics. Wiley, pp. 431-445]. Apparent rate constants for a disk rotation speed of 340 rpm increase from 0.07 0.02 to 0.25 0.02 mol m(-2) s(-1) in response to increasing temperature from 25 degrees to 80 degrees C. H diffusion coefficients increase from (2.9 to 9.2) x 10(-9) m(2) s(-1) over this temperature range with an apparent activation energy of 19 kJ mol(-1). (C) 1998 Elsevier Science B.V. All rights reserved

Quelques mcanismes chimiques du creusement des cavernes (plus _particulirement pour ltude de la zone noye), 1999, Lismonde, Baudouin
The classical influences of physical parameters and mixing corrosion are presented to study the equilibrium of the water-air-limestone chemical system. The frequent observation of cave levels in the mountain karstic systems is often associated with the greater facility of dissolution, near the water table. Some chemical mechanisms are analysed to show the greater karst corrosion on this level. Increased air pressure induces an increase in the saturation pCO2 of the water. Two confinement coefficients are used to analyse the role of a limited quantity of air in contact with water. The first (k) is the water mass/water + air mass ratio, the second (kn) is the mass of CO2 in water/ mass of CO2 in water and air ratio. These two ratios show that the latter coefficient varies with air pressure, but is proportional to the varying pCO2.

Linear and nonlinear input/output models for karstic springflow and flood prediction at different time scales, 1999, Labat D. , Ababou R. , Mangin A. ,
Karstic formations function as three-dimensional (3D) hydrological basins, with both surface and subsurface flows through fissures, natural conduits, underground streams and reservoirs. The main characteristic of karstic formations is their significant 3D physical heterogeneity at all scales, from fine fissuration to large holes and conduits. This leads to dynamic and temporal variability, e.g, highly variable flow rates, due to several concurrent flow regimes with several distinct response times. The temporal hydrologic response of karstic basins is studied here from an input/output, systems analysis viewpoint. The hydraulic behaviour of the basins is approached via the relationship between hydrometeorological inputs and outputs. These processes are represented and modeled as random, self-correlated and cross-correlated, stationary time processes. More precisely, for each site-specific case presented here, the input process is the total rainfall on the basin and the output process is the discharge rate at the outlet of the basin (karstic spring). In the absence of other data, these time processes embody all the available information concerning a given karstic basin. In this paper, we first present a brief discussion of the physical structure of karstic systems. Then, we formulate linear and nonlinear models, i.e. functional relations between rainfall and runoff, and methods for identifying the kernel and coefficients of the functionals (deterministic vs. statistical; error minimisation vs. polynomial projection). These are based mostly on Volterra first order (linear) or second order (nonlinear) convolution. In addition, a new nonlinear threshold model is developed, based on the frequency distribution of interannual mean daily runoff. Finally, the different models and identification methods are applied to two karstic watersheds in the french Pyrenees mountains, using long sequences of rainfall and spring outflow data at two different sampling rates (daily and semi-hourly). The accuracy of nonlinear and linear rainfall-runoff models is tested at three time scales: long interannual scale (20 years of daily data), medium or seasonal scale (3 months of semi-hourly data), and short scale or 'flood scale' (2 days of semi-hourly data). The model predictions are analysed in terms of global statistical accuracy and in terms of accuracy with respect to high flow events (floods)

Toward understanding transport in the Floridan karst, 1999, Loper D.
There is a strong need for better scientific knowledge of groundwater behavior in Floridan-type karstic aquifers and for better mechanisms to transfer such knowledge into practiceTo facilitate this transfer, a new scientific organization called the Hydrogeology Consortium has recently been establishedThe Consortium is described in detail elsewhere in this volumeIts mission is to cooperatively provide scientific knowledge applicable to groundwater resource management and protectionA necessary adjunct to the mission of the Consortium is the development of better models of transport and dispersion in karstic aquifersA first step in this development is elucidation of the shortcomings of the standard model of dispersionIn this model, dispersion is represented by an effective diffusivity, called the dispersion coefficient, which is the product of the mean flow speed and the decorrelation distanceIt is shown that this model does not correctly describe dispersion in an aquifer having porosity that is weakly correlated on a large scaleThat is, the concept of a decorrelation distance is not viable for a non-homogeneous aquiferOne approach toward the quantification of transport and dispersion in karstic aquifers to model the aquifer as a classic Darcian porous medium riddled by a distribution of macroscopic conduitsThe flow properties of this model are compatible with the standard Darcian model, but its transport equation is non-autonomous; it has coefficients that depend on the elapsed time

Controls on trace element (Sr-Mg) compositions of carbonate cave waters: implications for speleothem climatic records, 2000, Fairchild Ij, Borsato A, Tooth Af, Frisia S, Hawkesworth Cj, Huang Ym, Mcdermott F, Spiro B,
At two caves (Clamouse, S France and Ernesto, NE Italy), cave drip and pool waters were collected and sampled at intervals over a 2-3 year period. Mg/Ca and Sr/Ca concentration ratios, corrected for marine aerosols, are compared with those of bedrocks and, in some cases, aqueous leachates of soils and weathered bedrocks. Cave waters do not lie along mixing lines between calcite and dolomite of bedrock carbonate, but typically show enhanced and covarying Mg/Ca and Sr/Ca. Four factors are considered as controlling processes. (1) The much faster dissolution rate of calcite than dolomite allows for the possibility of increase of Mg/Ca if water-rock contact times are increased during drier conditions. A theoretical model is shown to be comparable to experimental leachates. (2) Prior calcite precipitation along a flow path is a powerful mechanism for generating enhanced and covarying Mg/Ca and Sr/Ca ratios. This mechanism requires the solution to lose CO, into pores or caverns. (3) Incongruent dolomite dissolution has only limited potential and is best regarded as two separate processes of dolomite dissolution and calcite precipitation. (4) selective leaching of Mg and Sr with respect to Ca is shown to be important in leachates from Ernesto where it appears to be a phenomenon of calcite dissolution. In general selective leaching can occur whenever Ca is sequestered into precipitates due to freezing or drying of soils, or if there is derivation of excess Sr and Mg from non-carbonate species. The Ernesto cave has abundant water supply which in the main chamber is derived from a reservoir with year-round constant P-CO2 of around 10(-2.4) and no evidence of calcite precipitation in the karst above the cave. Two distinct, bur overlying trends of enhanced and covarying Mg/Ca and Sr/Ca away from the locus of bedrock compositions are due to calcite precipitation within the cave and, at a variable drip site, due to enhanced selective leaching at slow drip rates. Mg-enhancement in the first chamber is due to a more dolomitic bedrock and longer residence times. The Clamouse site has a less abundant water supply and presents geochemical evidence of prior calcite precipitation. both in the cave and in overlying porous dolomite/dedolomitized limestone bedrock. Initial P-CO2 values as high as 10(-1) are inferred. Experimental incubations of Clamouse soils which generated enhanced P-CO2 and precipitated CaCO3 had compositions similar to the karst waters. Calcite precipitation is inferred to he enhanced in drier conditions. Hydrological controls on cave water chemistry imply that the trace element chemistry of speleothems may be interpretable in palaeohydrological terms. Drier conditions tends to promote not only longer mean residence times (enhancing dolomite dissolution and hence Mg/Ca), but also enhances degassing and calcite precipitation leading to increased Mg/Ca and Sr/Ca. (C) 2000 Elsevier Science B.V. All rights reserved

Groundwater resources and vulnerability in the Cretaceous Chalk of Northern Ireland, 2000, Barnes S,
A confined Cretaceous Chalk aquifer underlies approximately one quarter of Northern Ireland, yet little is known about its groundwater resource potential. This issue has been addressed on the catchment scale by analysing spring discharge and hydrochemical fluctuations. The Chalk springs are recharged by allogenic leakage and surface runoff from overlying Tertiary basalts. Sources connected to river-sinks show greater variation in flow and quality reflecting a much shorter residence time than those predominantly derived from the diffuse recharge. Discharge from the confined region becomes proportionally significant during prolonged dry spells, but is typically a minor component compared with groundwater circulation volumes in the unconfined region. Spring flood recessions are rapid (recession coefficients up to 0.125 per day) and suggest that the Chalk has a high hydraulic conductivity and a low storage capacity. These characteristics together, with the essentially impermeable matrix, are consistent with an aquifer dominated by a dispersed fracture network. Conceptual aquifer classification suggests that the outcrop region is a highly sensitive karst aquifer. The subcrop areas can only be exploited via boreholes and are likely to be less productive, although the water quality has been shown to be more stable and less vulnerable to contamination

Hydrologic analysis of discharge sustainability from an abandoned underground coal mine, 2000, Burbey Tj, Younos T, Anderson Et,
Discharge from flooded abandoned subsurface coal mines is considered a potential source for water supplies where other acceptable water sources are not available. The objective of this study was to develop procedures for determining sustainability of mine-water discharge using rainfall and discharge data for a case study site. The study site is located in southwest Virginia where Late Paleozoic sequences of sandstone, coal, and shale predominate. A rain gauge and a flow rate monitoring system were installed at the site and data were collected for a period of 100 days. The recording period corresponded with one of the driest periods in recent years and, therefore, provided valuable information regarding the flow sustainability during baseflow conditions. From available data on underground mining patterns, geology, and ground water flow regimes, it was determined that a coal mine aquifer exhibits hydraulic characteristics very similar to the extremely heterogeneous systems observed in karst aquifers, and the mine discharge is analogous to springflow. Thus, techniques commonly used in karst-water systems and springflow analysis were used to develop rainfall/mine-discharge relationships. Springflow recession analysis was performed on five rainfall recessions and the coefficient for each recession was compared and interpreted in light of known geologic information. It was found that the recession coefficients described the mine discharge adequately and the mine aquifer response to a rainfall pulse was very similar to the response from certain ts;pes of karst aquifers. A cross-correlation analysis was performed to verify the results of the recession analysis and to develop a 'black box' statistical model for discharge data. The correlation analysis proved the validity of springflow recession analysis for mine discharge. The recorded data length was not adequate to create a statistical model, however, but a procedure was proposed for a statistical model that could be used with large flow records. For the study site, the mine discharge was found to be sustainable for a prolonged period of time

Monthly and annual effective infiltration coefficients in Dinaric karst: example of the Gradole karst spring catchment, 2001, Bonacci O,
The problems and present methods for the calculation of monthly and annual effective infiltration coefficients in Dinaric karat catchments which cover areas smaller than 200 km(2) are discussed. An example is given of the catchment of the Gradole karat spring, which covers 114 km(2) The climate on the catchment is North Mediterranean, with average annual rainfall of 986 mm, average air temperature of 11.4 degreesC, and average discharge from the Gradole Spring of 1.98 m(3) s(-1). All the data refer to a period from 1987 to 1998. An auto-correlation analysis is carried out of daily and monthly discharges from the spring and monthly rainfall on the catchment. Special attention has been given to determination of monthly effective infiltration coefficients. It was found that the time-scale effect makes it infeasible to use the equation for effective infiltration coefficient, because it gives values greater than 1 in 25% of cases, which is theoretically impossible. Therefore, two different procedures for calculation of monthly effective infiltration coefficients are given, out of which one uses the master depletion curve. This procedure gives acceptable and physically well-established values of mean long-term monthly effective infiltration coefficients. Obtained values can be used for regional analyses as well as for water resources management in karat regions. There was also a strong relationship between mean monthly air temperatures of the catchment and mean monthly effective infiltration coefficients. It is found that rainfall distribution during the year significantly influences the annual effective infiltration coefficients, which for the Gradole catchment ranges between 0.356 and 0.763 with the mean value of 0.57

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