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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. ...

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. ...

Speleology in Kazakhstan

Shakalov on 11 Jul, 2012
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 A-horizon is the topmost eluviated horizon of a soil profile [16].?

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

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Browse Speleogenesis Issues:

KarstBase a bibliography database in karst and cave science.

Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
See all featured articles
Featured articles from other Geoscience Journals
Karst environment, Culver D.C.
Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs, Bontognali, Tomaso R.R.; D’Angeli Ilenia M.; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano M.; Gonzales, Esteban R. G.; De Waele, Jo
Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
Microbial mediation of complex subterranean mineral structures, Tirato, Nicola; Torriano, Stefano F.F;, Monteux, Sylvain; Sauro, Francesco; De Waele, Jo; Lavagna, Maria Luisa; D’Angeli, Ilenia Maria; Chailloux, Daniel; Renda, Michel; Eglinton, Timothy I.; Bontognali, Tomaso Renzo Rezio
Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria), Briestensky, Milos; Rowberry, Matt; Stemberk, Josef; Stefanov, Petar; Vozar, Jozef; Sebela, Stanka; Petro, Lubomir; Bella, Pavel; Gaal, Ludovit; Ormukov, Cholponbek;
See all featured articles from other geoscience journals

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Your search for sensitivity analysis (Keyword) returned 14 results for the whole karstbase:
The role of tributary mixing in chemical variations at a karst spring, Milandre, Switzerland, , Perrin J. , Jeannin P. Y. , Cornaton F. ,
SummarySolute concentration variations during flood events were investigated in a karst aquifer of the Swiss Jura. Observations were made at the spring, and at the three main subterraneous tributaries feeding the spring. A simple transient flow and transport numerical model was able to reproduce chemographs and hydrographs observed at the spring, as a result of a mixing of the concentration and discharge of the respective tributaries. Sensitivity analysis carried out with the model showed that it is possible to produce chemical variations at the spring even if all tributaries have constant (but different for each of them) solute concentrations. This process is called tributary mixing. The good match between observed and modelled curves indicate that, in the phreatic zone, tributary mixing is probably an important process that shapes spring chemographs. Chemical reactions and other mixing components (e.g. from low permeability volumes) have a limited influence.Dissolution-related (calcium, bicarbonate, specific conductance) and pollution-related parameters (nitrate, chloride, potassium) displayed slightly different behaviours: during moderate flood events, the former showed limited variations compared to the latter. During large flood events, both presented chemographs with significant changes. No significant event water participates in moderate flood events and tributary mixing will be the major process shaping chemographs. Variations are greater for parameters with higher spatial variability (e.g. pollution-related). Whereas for large flood events, the contribution of event water becomes significant and influences the chemographs of all the parameters. As a result, spring water vulnerability to an accidental pollution is low during moderate flood events and under base flow conditions. It strongly increases during large flood events, because event water contributes to the spring discharge

Karst aquifer genesis - Modelling approaches and controlling parameters, 1997, Sauter M. , Liedl R. , Clemens T. , Hiickinghaus D.
The quantification of regional groundwater flow and the transport of dissolved substances in a karst system generally poses problems in parameter identification as well as in the modelling of the above processes. On the other hand, available qualitative and quantitative geological information on the history of the development of karst aquifers, which can provide information on the distribution of karstitied horizons within the modelled domain, are generally not considered. A model has been developed, capable of simulating the interactions between the different processes, i.e. flow, transport coupled with carbonate dissolution, taking into account the varying boundary conditions, e.g. changes in geological and geomorphological (base level) and climatic conditions (recharge depth, temperature). A sensitivity analysis of the duration of karstification to changes in climatic parameters and physico-chemical constants of carbonate dissolution shows that the equilibrium concentration of calcium and the initial diameter of the conduits are very dominant factors.

Simulation of the development of karst aquifers by using a pipe flow model coupled to a continuum model, 2, Model verification and sensitivity analysis., 1998, Clemens T. , Huckinghaus D. , Sauter M. , Liedl R. , Teutsch G.

Karst aquifer evolution in fractured rocks, 1999, Kaufmann G. , Braun J. ,
We study the large-scale evolution and flow in a fractured karst aquifer by means of a newly developed numerical method. A karst aquifer is discretized into a set of irregularly spaced nodal points, which are connected to their set of natural neighbors to simulate a network of interconnected conduits in two dimensions. The conduits are allowed to enlarge by solutional widening. The geometric flexibility of this method, along with a simplified model for the dissolution kinetics within the system water-carbon dioxide-calcite, enables us to study both laminar and turbulent flow in a karst aquifer during its early phase of evolution. A sensitivity analysis is conducted for parameters such as conduit diameter, hydraulic pressure differences, and recharge conditions along the surface of the aquifer and shows that passage evolution depends strongly on the recharge condition and the amount of water available. Under fixed hydraulic head boundary conditions an early single-passage system develops under laminar conditions and is transformed into a maze-like passage system after the onset of turbulence. Fixed recharge boundary conditions are more likely to result in a branchwork-like passage system, although the addition of distributed recharge may lead to a maze-like system of secondary passages

Sensitivity analysis for the EPIK method of vulnerability assessment in a small karstic aquifer, southern Belgium, 2000, Gogu Radu Constantin, Dassargues Alain,

Simulation of daily and monthly stream discharge from small watersheds using the SWAT model, 2000, Spruill C. A. , Workman S. R. , Taraba J. L. ,
The Soil and Water Assessment Tool (SWAT) was evaluated and parameter sensitivities were determined while modeling daily streamflows in a small central Kentucky watershed over a two-year period. Streamflow data from 1996 were used to calibrate the model and streamflow data from 1995 were used for evaluation. The model adequately predicted the trends in daily streamflow during this period although Nash-Sutcliffe R-2 values were -0.04 and 0.19 for 1995 and 1996, respectively The model poorly predicted the timing of some peak flow values and recession rates during the last half of 1995. Excluding daily peak flow values from August to December improved the daily R-2 to 0.15, which was similar to the 1996 daily R2 value. The Nash-Sutcliffe R-2 for monthly total flows were 0.58 for 1995 and 0.89 for 1996 which were similar to values found in the literature. Since very little information was available on the sensitivity of the SWAT model to various inputs, a sensitivity analysis/calibration procedure was designed to evaluate parameters that were thought to influence stream discharge predictions. These parameters included, drainage area, slope length, channel length, saturated hydraulic conductivity, and available water capacity. Minimization of the average absolute deviation between observed and simulated streamflows identified optimum values/ranges for each parameter. Saturated hydraulic conductivity alpha baseflow factor; drainage area, channel length, and channel width were the most sensitive parameters in modeling the karst influenced watershed. The sensitivity analysis process confirmed die trace studies in the karst watershed that a much larger area contributes to streamflow than can be described by the topographic boundaries. Overall, the results indicate that the SWAT model can be an effective tool for describing monthly, runoff from small watersheds in central Kentucky that have developed on karat hydrology however calibration data are necessary to account for solution channels draining into or out of the topographic watershed

Groundwater modelling in aquifers with highly karstic and heterogeneous characteristics (KHC) in Palestine, 2002, Froukh Lj,
Groundwater modelling is hindered by the lack of adequate information about the groundwater system and hence the need for an interactive and efficient system for data preparation and results analysis. Such a lack of information usually necessitates the use of tedious iterative methodology within a sensitivity analysis scheme. The heterogeneous aquifer systems complicate the issue since more data is required to simulate the system. This study demonstrates the integrated approach to bridge the gap between data handling and modelling. The karst cretaceous aquifer system (complex aquifer system) of the Eastern Basin in the West Bank is used to illustrate this approach. The groundwater modelling approach integrates the outputs from different programs for data preparation and analysis. These include (1) Groundwater Database (GWW) (2) Geographic Information System (GIS) (3) Groundwater Modelling System (GMS). In addition, the paper will summarize the data collection efforts, problems faced and experience gained working with heterogeneous media. This involves linking the results from various field investigations for groundwater development programs in the West Bank

Dam sites in soluble rocks: a model of increasing leakage by dissolutional widening of fractures beneath a dam, 2003, Romanov D. , Gabrovsek F. , Dreybrodt W. ,
Water flowing through narrow fissures and fractures in soluble rock, e.g. limestone and gypsum, widens these by chemical dissolution. This process, called karstification, sculptures subterranean river systems which drain most of their catchment. Close to dam sites, unnaturally high hydraulic gradients are present to drive the water impounded in the reservoir downstream through fractures reaching below the dam. Under such conditions, the natural process of karstification is accelerated to such an extent that high leakage rates may arise, which endanger the operation of the hydraulic structure. Model simulations of karstification below dams by coupling equations of dissolutional widening to hydrodynamic flow are presented. The model scenario is a dam 100 in wide in limestone or gypsum. The modelling domain is a two-dimensional slice 1 m wide directed perpendicular to the dam. It extends 375 in vertically and 750 in horizontally. The dam is located in its center. This domain is divided by fractures and fissures into blocks of 7.5 x 7.5 x 1 m. The average aperture width of the fractures is 0.02 cm. We performed model runs on standard scenarios for a dam site in limestone with the height H of impounded water 150 in, a horizontal impermeable apron of width W=262 m and a grouting curtain reaching down to a depth of G=97 m. In a second scenario, we changed these construction features to G=187 m and W=82 m. To calculate widening of the fractures, well-established experimental data on the dissolution of limestone and gypsum have been used as they occur in such geochemical settings. All model runs show similar characteristic behaviour. Shortly after filling, the reservoir exhibits a small leakage of about 0.01 m(-3) s(-1), which increases steadily until a breakthrough event occurs after several decades with an abrupt increase of leakage to about 1 m(3) s(-1) within the short time of a few years. Then, flow in the fractures becomes turbulent and the leakage increases to 10 m(3) s(-1) in a further time span of about 10 years. The widths of the fractures are visualized in various time steps. Small channels propagate downstream and leakage rises slowly until the first channel reaches the surface downstream. Then breakthrough occurs, the laminar flow changes to turbulent and a dense net of fractures which carry flow is established. We performed a sensitivity analysis on the dependence of breakthrough times on various parameters, determining breakthrough. These are the height of impounded water H, the depth G of grouting, the average aperture width a(0) of the fractures and the chemical parameters, which are c(eq) the equilibrium concentration of Ca with respect to calcite and the Ca-concentration c(in) of the inflowing water. The results show that the most critical parameter is a(0). At fracture aperture widths of 0.01 cm, breakthrough times are above 500 years. For values of a(0)>0.02 cm, however, breakthrough times are within the lifetime of the structure. We have also modelled dam sites in gypsum, which exhibit similar breakthrough times. However, after breakthrough, owing to the much larger dissolution rates of gypsum, the time until unbearable leakage is obtained, is only a few years. The modelling can be applied to complex geological settings, as phreatic cave conduits below the dam, or a complex stratigraphy with varying properties of the rock with respect to hydraulic conductivity and solubility. A few examples are given. In conclusion, our results support the assumption that increasing leakage of dam sites may be caused by dissolutional widening of fractures. (C) 2003 Elsevier Science B.V. All rights reserved

New risk-consequence rockfall hazard rating system for Missouri highways using digital image analysis, 2005, Maerz N. H. , Youssef A. , Fennessey T. W. ,
The Missouri Rockfall Hazard Rating System (MORFH RS) is a new scheme for rating rockfall hazards along the roads of the Missouri State highway system. Existing rating systems used in other jurisdictions focus on the risk of failure and ignore the consequence of failure, or they lump the ratings for risk and consequence together. Missouri highway rock cuts tend to have low heights but are typically highly weathered, with special problems from karst and paleokarst. In MORFH RS, risk and consequence factors are given equal weight but isolated from each other. MORFH RS utilizes two phases: 1) identification of the most potentially problematic rock cuts using mobile digital video logging; 2) characterization and prioritization of remediation for the potentially problematic rock cuts identified in phase 1, using MORFH RS. In phase 2 four types of parameters are evaluated: 1) parameters that can be measured on computer scaled video images; 2) parameters which are descriptive, and need field evaluation; 3) parameters which are obtained from MODOT records; 4) conditional parameters which are evaluated under specific conditions. Only those parameters were selected that were deemed meaningful and/or relatively easy to measure or estimate. Parameters were assigned to either a risk or consequence category or both. MORFH RS has been tested on sections of Missouri highways. About 300 rock cuts were evaluated and used to prepare, modify, test, and verify the system. Sensitivity analysis of the system was done by quantifying potential errors in the video measurements and by a rating comparison of 12 MODOT and University of Missouri-Rolla (UMR) personnel on 10 rock cuts along Highway 63

δ13C profiles along growth layers of stalagmites: Comparing theoretical and experimental results, 2008, Romanov D. , Kaufmann G. , Dreybrodt W.

The isotopic carbon ratio of a calcite-precipitating solution flowing as a water film on the surface of a stalagmite is determined by Rayleigh distillation. It can be calculated, when the -concentration of the solution at each surface point of the stalagmite and the fractionation factors are known. A stalagmite growth model based entirely on the physics of laminar flow and the well-known precipitation rates of a supersaturated solution of calcite, without any further assumptions, is employed to obtain the spatial distribution of the -concentration, which contributes more than 95% to the dissolved inorganic carbon (DIC). The δ13C profiles are calculated along the growth surface of a stalagmite for three cases: (A) isotopic equilibrium of both CO2 outgassing and calcite precipitation; (B) outgassing of CO2 is irreversible but calcite precipitation is in isotopic equilibrium. (C) Both CO2 outgassing and calcite precipitation are irreversible. In all cases the isotopic shift δ13C increases from the apex along the distance on a growth surface. In cases A and B, calcite deposited at the apex is in isotopic equilibrium with the solution of the drip water. The difference between δ13C at the apex and the end of the growth layer is independent of the stalagmite’s radius, but depends on temperature. For case A, it is about half the value obtained for cases B and C. In case C, the isotopic composition of calcite at the apex equals that of the drip water, but further out it becomes practically identical with that of case B. The growth model has been applied to field data of stalagmite growth, where the thickness and the δ13C of calcite precipitated to a glass plate located on the top of a stalagmite have been measured as function of the distance from the drip point. The calculated data are in good agreement to the observed ones and indicate that deposition occurred most likely under conditions B, eventually also C. A sensitivity analysis has been performed, which shows that within the limits of observed external parameters, such as drip rates and partial pressure of carbon dioxide PCO2 in the cave, the results remain valid.

Modified DRASTIC assessment for intrinsic vulnerability mapping of karst aquifers: a case study , 2011, Mimi Ziad A. , Mahmoud Nidal, Abu Madi Maher

Groundwater in karstic aquifers can be dangerously sensitive to contamination. In this paper, DRASTIC assessment was modified and applied, for the first time, to address the intrinsic vulnerability for karst aquifers. The theoretical weights of two of DRASTIC’s parameters (aquifer media and hydraulic conductivity) were modified through sensitivity analysis. Two tests of sensitivity analyses were carried out: the map removal and the single parameter sensitivity analyses. The modified assessment was applied for the karst aquifers underlying Ramallah District (Palestine) as a case study. The aquifer vulnerability map indicated that the case study area is under low, moderate and high vulnerability of groundwater to contamination. The vulnerability index can assist in the implementation of groundwater management strategies to prevent degradation of groundwater quality. The modified DRASTIC assessment has proven to be effective because it is relatively straightforward, use data that are commonly available or estimated and produces an end product that is easily interpreted.

Comparative application of two methods (COP and PaPRIKa) for groundwater vulnerability mapping in Mediterranean karst aquifers (France and Spain) , 2011, Marin A. I. , Dorfliger N. , Andreo O.

A comparative test of two vulnerability mapping methods (COP and PaPRIKa) specifically dedicated to for karst aquifers was carried out on two Mediterranean carbonate aquifers. The vulnerability maps obtained for each aquifer present important differences. To identify and determine the origin of these differences, the results were statistically analyzed using sensitivity analysis, coefficients of determination and scatter graphs. In addition, the global vulnerability (Gv) parameter was used to measure the general vulnerability of the aquifer and to compare the results obtained. This statistical analysis led us to conclude that the main cause of differences between these two methods used to assess aquifer vulnerability lie in the relative importance of the parameters employed in calculating the vulnerability index. For the PaPRIKa method, the variable related to infiltration (slope and karst features) has the most influence, with less weight being assigned to the protective capacity of layers overlying the aquifer. For the COP method, the most influent variable is defined by the layers overlying the aquifer, together with infiltration characteristics, determined by the relative importance of different forms of infiltration in each aquifer. The vulnerability mappings performed using the COP method present greater coherence with the known hydrogeological behavior of the study areas, especially the Spanish aquifers. Nevertheless, further hydrogeological investigations are needed, such as ones to validate the obtained vulnerability maps.

Comparative study of specific groundwater vulnerability of a karst aquifer in central Florida, 2012, Van Beynen P. E. , Niedzielski M. A. , Bialkowskajelinska E. , Alsharifa K. , Matusick J.

The Floridan aquifer system (FAS) is known to be one of the most productive aquifer systems in the USA. With the FAS being a karst aquifer, it presents unique challenges to land use planners because of inherent vulnerabilities to contamination through direct connections between the aquifer and the surface. In this study a new Geographic Information Systems (GIS) -based index, the Karst Aquifer Vulnerability Index (KAVI), incorporates geologic layers used in intrinsic groundwater vulnerability models (GVMs) plus an epikarst layer specific to karst, with land use coverages to create a specific groundwater vulnerability model. The KAVI model was compared to another specific vulnerability model, the Susceptibility Index (SI). Tabulation of the percentage areas of vulnerability classes reveals major differences between the two models with SI suggesting greater vulnerability for the study area than KAVI. Validation of these two models found that KAVI vulnerability levels best reproduced spatially varying concentrations of nitrate in the aquifer. Sensitivity analysis, the application of a variation index and measuring the effective weights for each parameter included in KAVI confirmed the importance of closed depressions but also aquifer hydraulic conductivity. The inclusion of land use was justified; however, effective weight analysis determined its assigned weight was too high as used in the initial calculation of KAVI.

Simulation of flow processes in a large scale karst system with an integrated catchment model (Mike She) Identification of relevant parameters influencing spring discharge, 2012, Doummar J. , Sauter M. , Geyer T.

In a complex environment such as karst systems, it is difficult to assess the relative contribution of the different components of the system to the hydrological system response, i.e. spring discharge. Not only is the saturated zone highly heterogeneous due to the presence of highly permeable conduits, but also the recharge processes. The latter are composed of rapid recharge components through shafts and solution channels and diffuse matrix infiltration, generating a highly complex, spatially and temporally variable input signal. The presented study reveals the importance of the compartments vegetation, soils, saturated zone and unsaturated zone. Therefore, the entire water cycle in the catchment area Gallusquelle spring (Southwest Germany) is modelled over a period of 10 years using the integrated hydrological modelling system Mike She by DHI (2007). Sensitivity analyses show that a few individual parameters, varied within physically plausible ranges, play an important role in reshaping the recessions and peaks of the recharge functions and consequently the spring discharge. Vegetation parameters especially the Leaf Area Index (LAI) and the root depth as well as empirical parameters in the relationship of Kristensen and Jensen highly influence evapotranspiration, transpiration to evaporation ratios and recharge respectively. In the unsaturated zone, the type of the soil (mainly the hydraulic conductivity at saturation in the water retention and hydraulic retention curves) has an effect on the infiltration/evapotranspiration and recharge functions. Additionally in the unsaturated karst, the saturated moisture content is considered as a highly indicative parameter as it significantly affects the peaks and recessions of the recharge curve. At the level of the saturated zone the hydraulic conductivity of the matrix and highly conductive zone representing the conduit are dominant parameters influencing the spring response. Other intermediate significant parameters appear to influence the characteristics of the spring response yet to a smaller extent, as for instance bypass and the parameters a in the Van Genuchten relation for soil moisture content curves.

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