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Enviroscan Ukrainian Institute of Speleology and Karstology


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Community news

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 globularite is small crystals of calcite tipped with spheres composed of radiating fibers [10].?

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


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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
See all featured articles
Featured articles from other Geoscience Journals
Karst environment, Culver D.C.
Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs, Bontognali, Tomaso R.R.; D’Angeli Ilenia M.; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano M.; Gonzales, Esteban R. G.; De Waele, Jo
Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
Microbial mediation of complex subterranean mineral structures, Tirato, Nicola; Torriano, Stefano F.F;, Monteux, Sylvain; Sauro, Francesco; De Waele, Jo; Lavagna, Maria Luisa; D’Angeli, Ilenia Maria; Chailloux, Daniel; Renda, Michel; Eglinton, Timothy I.; Bontognali, Tomaso Renzo Rezio
Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria), Briestensky, Milos; Rowberry, Matt; Stemberk, Josef; Stefanov, Petar; Vozar, Jozef; Sebela, Stanka; Petro, Lubomir; Bella, Pavel; Gaal, Ludovit; Ormukov, Cholponbek;
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Your search for modelling (Keyword) returned 156 results for the whole karstbase:
Showing 136 to 150 of 156
The impact of glacier ice-contact and subglacial hydrochemistry on evolution of maze caves: A modelling approach, 2010,
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Skoglund Rannveig Ovrevik, Lauritzen Steinerik, Gabrovsek Franci

Labyrinth and maze cave networks are a conspicuous feature in formerly glaciated stripe karst in Scandinavia. Often found in topographically “impossible” situations, their genesis is attributed to glacial ice-contact conditions. This is further supported by observing that individual networks may either be influent, effluent or through-flow; depending on the attitude of the host rock and former glacier directions. The ice-contact hypothesis is tested by using a finite difference, fracture network model where chemical and hydrological conditions can be varied. Subglacial chemistry alone (low partial pressure of CO2, low temperature) is not sufficient to favour mazes over linear caves. However, when coupled with high input saturation ratio, high and varied hydraulic gradients and glacial hydrology, the model produced cave patterns comparable in scale and complexity to our field examples.


Conceptual modelling of brine flow into aquifers adjacent to the Konarsiah salt diapir, Iran, 2010,
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Zarei Mehdi, Raeisi Ezzat

The Konarsiah salt diapir is located in the Simply Folded Zone of the Zagros Mountain, south Iran. Salt,extruding from two vents along a fault, spreads downslope as a salt glacier over the adjacent formations. Eight small permanent brine springs emerge from the Konarsiah salt body, with average total dissolved solids of 327.3 g/L. The diapir is in direct contact with several aquifers, namely, the karstic Eastern and Western Sarvak, karstic Eastern Asmari, Firouzabad, Konarsiah Plain and Shour. It is also surrounded by a number of impermeable formations. The springs and seepage sections emerging from the aquifers adjacent to the diapir are unexpectedly saline or brackish. Electrical conductivity, total dissolved solids, flow rate, temperature and major ion concentrations were measured monthly from September 2007 to August 2008 at 37 sampling sites, including springs, surface waters, boreholes and wells.
The study indicates that the source of salinity of the adjacent aquifers is halite dissolution of the diapir. Conceptual models of groundwater flow are proposed for the adjacent karst aquifers based on the geological setting, water budget, local base of erosion, isotope data and the profile of the water table. The share of the diapir brine in the Eastern Sarvak aquifer, the Western aquifers (Sarvak, Asmari and Shour) and Konarsiah Plain are 1.8 L/s, 0.8 L/s and 9.1 L/s, respectively. Most of this brine ultimately releases into the Firouzabad River and changes the TDS of this river from 9.21 g/L to 11.61 g/L.
To drain the brine flowing into the Eastern Sarvak aquifer and hence reduce the aquifer's salinity it might be feasible to construct a qanat (a man-made underground gallery transferring groundwater to the surface by gravity) at the aquifer's contact with the Konarsiah diapir. To exploit the fresh karst water of the Western Sarvak aquifer before it is contaminated by the Konarsiah brine, several wells could be constructed well away from the diapir.


Reconstruction of the prehistoric entrance of the Chauv cave (Ardèche, France): the contribution of geomorphologic analysis and 3d modelling, 2010,
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Delannoy J. J. , Sadier B. , Jaillet S. , Ployon E. , Geneste J. M.

New Insight into Karst Genesis, 2010,
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The paper sets forth a new hypothesis that connects karst origin with rock mass evolution in

the area of endogenous ring structures. The hypothesis is confirmed by correlation of karst

manifestations on the Earth’s surface with ring structures, by results of karst formation

physical and digital modelling and by resemblance of the modelling results and field

observation data


Laser Scanning Technology for the Hypogean Survey: the case of Santa Barbara Karst System (Sardinia, Italy), 2011,
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Canevese Erminio Paolo, Forti Paolo , Naseddu Angelo, Ottelli Luciano, Tedeschi Roberta

The morphological knowledge of the territory, both in its surface and subterranean aspects, is the main premise to all decision-making procedures as well as all planning and management activities. Knowledge takes shape into reliable precise and complete thematic cartography and databases, which are necessary for anybody dealing with underground contexts: speleologists, scientists, public administrations, managing authorities etc.
Surveys in caves are normally carried out with traditional techniques and instruments, which are essential for a first representation but not enough for a pragmatic effective topographic approach. Laser scanning technique can be an alternative to the traditional systems. Laser scanning quickly acquires the shape of cavities as “point clouds” (x, y, z coordinates and colour values) and produces a high precision database of the surveyed object. Laser scanning technology is therefore a feasible way to document caves in a precise exhaustive way, limiting risks relating to lack and/or inadequacy of data.
The present paper explains the laser scanning survey carried out in San Giovanni mine near Iglesias (Sardinia, Italy), particularly in Santa Barbara and Santa Barbara 2 caves, the data post-processing and three-dimensional modelling of “point clouds” (operations performed with a dedicated software), and
the use of the obtained digital model. Moreover, the paper describes
the advantages of laser scanning for the hypogean survey
in comparison to traditional methods and the future potentialities
of a broad application of laser scanning instruments
in caves.


On the formation of collapse dolines: A modelling perspective, 2011,
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Gabrovš, Ek Franci, Stepiš, Nik Uroš,

Collapse dolines are among the most striking surface features in karst areas. Although they can be the result of different formation mechanisms, evidence suggests that large collapse dolines form due to chemical and mechanical removal of material at and below the level of groundwater. We have applied a genetic model of a two-dimensional fracture network to calculate the rate of dissolutional bedrock removal in the heavily fractured (crushed) zone intersecting a karst conduit in the phreatic zone. To account for infilling and breakdown processes in the crushed zone two simple rules were added to the basic model: 1) continuous infilling of dissolutionally created voids prevents fractures from growing beyond some limited aperture, although the dissolution proceeds, 2) discontinuous collapsing causes sudden closure of a fracture once some critical aperture has been reached. Both rules limit the transmissivity of the network and the related flow rates. Therefore, the constant head difference between the input and the output points is sustained and the flow remains distributed over the entire crushed zone. Provided that restrictions posed by the two rules permit turbulent flow, dissolution rates also remain high in the entire region. High surface area of water–rock contact and high dissolution rates result in high overall removal rates of rock from the crushed zone, one of the necessary conditions for the formation of large closed depressions. Despite the fact that the model neglects some processes and dynamics that would increase the removal rate, the results suggest that large closed depressions could form in the order of 1 million years.


A preliminary analysis of failure mechanisms in karst and man-made underground caves in Southern Italy, 2011,
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Parise M. , Lollino P.

Natural and anthropogenic caves may represent a potential hazard for the built environment, due to the occurrence of instability within caves, that may propagate upward and eventually reach the ground surface, inducing the occurrence of sinkholes. In particular, when caves are at shallow depth, the effects at the ground surface may be extremely severe. Apulia region (southern Italy) hosts many sites where hazard associated with sinkholes is very serious due to presence of both natural karst caves and anthropogenic cavities, the latter being mostly represented by underground quarries. The Pliocene–Pleistocene calcarenite (a typical soft rock) was extensively quarried underground, by digging long and complex networks of tunnels. With time, these underground activities have progressively been abandoned and their memory lost, so that many Apulian towns are nowadays located just above the caves, due to urban expansion in the last decades. Therefore, a remarkable risk exists for society, which should not be left uninvestigated.

The present contribution deals with the analysis of the most representative failure mechanisms observed in the field for such underground instability processes and the factors that seem to influence the processes, as for example those causing weathering of the rock and the consequent degradation of its physical and mechanical properties. Aimed at exploring the progression of instability of the cavities, numerical analyses have been developed by using both the finite element method for geological settings represented by continuous soft rock mass, and the distinct element method for jointed rock mass conditions. Both the effects of local instability processes occurring underground and the effects of the progressive enlargement of the caves on the overall stability of the rock mass have been investigated, along with the consequent failure mechanisms. In particular, degradation processes of the rock mass, as a consequence of wetting and weathering phenomena in the areas surrounding the caves, have been simulated. The results obtained from the numerical simulations have then been compared with what has been observed during field surveys and a satisfactory agreement between the numerical simulations and the instability processes, as detected in situ, has been noticed.


Modelling of slope processes on karst , 2011,
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Stepinik Uro, Kosec Gregor

The present paper is concerned with the modelling of the karst slope processes. A simple straightforward one dimensional physical model is introduced in order to assess basic behaviour of the slope development. The model takes in account mass continuity of weathered material, the mechanical and chemical weathering of the bedrock. The paper focuses on the slope formation
with respect to the ratios between different magnitudes of governing processes (mechanical and chemical weathering and mass movement). The introduced approach representsa first step in understanding slope processes and does not pose a realistic quantitative comparison with field measurements. However, the results gathered with the model show good qualitative
agreement with the field observations. Three different representative cases are studied: dominant mechanical weathering
case, balanced mechanical and chemical weathering case and dominant chemical weathering case.


Influence of initial heterogeneities and recharge limitations on the evolution of aperture distributions in carbonate aquifers, 2011,
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Hubinger B. , Birk S.

Karst aquifers evolve where the dissolution of soluble rocks causes the enlargement of discrete pathways along fractures or bedding planes, thus creating highly conductive solution conduits. To identify general interrelations between hydrogeological conditions and the properties of the evolving conduit systems the aperture-size frequency distributions resulting from generic models of conduit evolution are analysed. For this purpose, a process-based numerical model coupling flow and rock dissolution is employed. Initial protoconduits are represented by tubes with log-normally distributed aperture sizes with a mean of 0.5 mm. Apertures are spatially uncorrelated and widen up to the metre range due to dissolution by chemically aggressive waters. Several examples of conduit development are examined focussing on influences of the initial heterogeneity and the available amount of recharge. If the available recharge is sufficiently high the evolving conduits compete for flow and those with large apertures and high hydraulic gradients attract more and more water. As a consequence, the positive feedback between increasing flow and dissolution causes the breakthrough of a conduit pathway connecting the recharge and discharge sides of the modelling domain. Under these competitive flow conditions dynamically stable bimodal aperture distributions are found to evolve, i.e. a certain percentage of tubes continues to be enlarged while the remaining tubes stay small-sized. The percentage of strongly widened tubes is found to be independent of the breakthrough time and decreases with increasing heterogeneity of the initial apertures and decreasing amount of available water. If the competition for flow is suppressed because the availability of water is strongly limited breakthrough of a conduit pathway is inhibited and the conduit pathways widen very slowly. The resulting aperture distributions are found to be unimodal covering some orders of magnitudes in size. Under these suppressed flow conditions the entire range of apertures continues to be enlarged. Hence, the number of tubes reaching aperture sizes in the order of centimetres or decimetres continues to increase with time and in the long term may exceed the number of large-sized tubes evolving under competitive flow conditions. This suggests that conduit development under suppressed flow conditions may significantly enhance the permeability of the formation e.g. in deep-seated carbonate settings.


The significance of turbulent flow representation in single-continuum models, 2011,
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Reimann T. , Rehrl C. , Shoemaker W. B. , Geyer T. , Birk S.

Karst aquifers evolve where the dissolution of soluble rocks causes the enlargement of discrete pathways along fractures or bedding planes, thus creating highly conductive solution conduits. To identify general interrelations between hydrogeological conditions and the properties of the evolving conduit systems the aperture-size frequency distributions resulting from generic models of conduit evolution are analysed. For this purpose, a process-based numerical model coupling flow and rock dissolution is employed. Initial protoconduits are represented by tubes with log-normally distributed aperture sizes with a mean ?0 = 0.5 mm for the logarithm of the diameters. Apertures are spatially uncorrelated and widen up to the metre range due to dissolution by chemically aggressive waters. Several examples of conduit development are examined focussing on influences of the initial heterogeneity and the available amount of recharge. If the available recharge is sufficiently high the evolving conduits compete for flow and those with large apertures and high hydraulic gradients attract more and more water. As a consequence, the positive feedback between increasing flow and dissolution causes the breakthrough of a conduit pathway connecting the recharge and discharge sides of the modelling domain. Under these competitive flow conditions dynamically stable bimodal aperture distributions are found to evolve, i.e. a certain percentage of tubes continues to be enlarged while the remaining tubes stay small-sized. The percentage of strongly widened tubes is found to be independent of the breakthrough time and decreases with increasing heterogeneity of the initial apertures and decreasing amount of available water. If the competition for flow is suppressed because the availability of water is strongly limited breakthrough of a conduit pathway is inhibited and the conduit pathways widen very slowly. The resulting aperture distributions are found to be unimodal covering some orders of magnitudes in size. Under these suppressed flow conditions the entire range of apertures continues to be enlarged. Hence, the number of tubes reaching aperture sizes in the order of centimetres or decimetres continues to increase with time and in the long term may exceed the number of large-sized tubes evolving under competitive flow conditions. This suggests that conduit development under suppressed flow conditions may significantly enhance the permeability of the formation, e.g. in deep-seated carbonate settings.


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,
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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.


Piezometric and hydrogeochemical characterization of groundwater circulation in complex karst aquifers. A case study: the Mancha Real-Pegalajar aquifer (Southern Spain), 2012,
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Gonzalezramon A. , Lopezchicano M. , Rubiocampos J. C.

A small karst aquifer of great structural complexity has been subjected to significant resource withdrawal over recent decades. This exploitation aroused social conflict due to the effect it has had on emblematic springs. This research has analysed piezometric data collected over the course of 12 years and the spatial hydrochemical data supplied by the main water points associated with it. The spatial and temporal evolution of the main chemical species in the groundwater and the hydrogeochemical processes affecting them have been studied, modelling them with the programme PHREEQC. These data suggest a complicated model of hydrogeological function with sectors storing water at different depths and connected to each other locally as determined by the geological structure.

 


Modelling hydrostratigraphy and groundwater flow of a fractured and karst aquifer in a Mediterranean basin (Salento peninsula, southeastern Italy), 2012,
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Giudici M. , Margiotta S. , Mazzone F. , Negri S. , Vassena C.

The control exerted by the hydrostratigraphic structure on aquifer recharge, groundwater flow and discharge along the coastal areas of a Mediterranean basin (Salento peninsula, about 5,000 km2 wide, southern Italy) is assessed through the development and application of a groundwater flow model based on the reconstruction of the hydrostratigraphic architecture at the regional scale. The hydrostratigraphic model, obtained by processing surface and subsurface data, is applied to map the top of the main aquifer, which is hosted in the deep hydrostratigraphic unit corresponding to Cretaceous and Oligocene limestones with complex geometrical relationships with the sea. It is also used to estimate the aquifer recharge, which occurs by percolation through overlying younger sediments with low permeability. These data are completed with information about the soil use to estimate water abstraction for irrigation and with literature data to estimate the water abstraction for drinking and industrial purposes. The above-sketched conceptual model is the basis for a finite difference groundwater 2D pseudo-stationary flow model, which assumes the following fundamental approximations: the fractured and karst limestone hydrostratigraphic unit can be approximated, at the model scale, as a continuous medium for which the discrete Darcy’s law is valid; the transition zone between salt and fresh water is so small with respect to the grid spacing that the Ghyben–Herzberg’s approximation for a sharp interface can be applied. Along the coastline different boundary conditions are assigned if the top of the limestone hydrostratigraphic unit lies either above the sea level (the aquifer has a free surface and fresh water is drained), or below the sea level (the aquifer is under pressure and the contact with sea occurs off-shore). The groundwater flow model correctly predicts the areas where the aquifer is fully saturated with salt water.


SPELEOGENESIS ALONG DEEP REGIONAL FAULTS BY ASCENDING WATERS: CASE STUDIES FROM SLOVAKIA AND CZECH REPUBLIC, 2012,
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Bella Pavel, Bosak Pavel

The most conspicuous six examples illustrating ascending (perascensum) speleogenesis linked with deep faults/fault systemswere selected from Slovakia and Czech Republic. In the past,the caves have been described as product of phreatic, epiphreaticand vadose speleogenesis related to the evolution of localwater courses and valley incision, and linked mostly with Pleistocenegeomorphic evolution. Our analysis illustrates severalcommon characteristics of caves: (1) they developed along or inclose vicinity of deep faults/fault zones, commonly of regionalimportance; (2) the groundwater ascended due to deep faults/fault systems mostly as results of deep regional circulation ofmeteoric waters from adjacent karst or nonkarst areas; (3) the3D mazes and labyrinths dominate in cave morphology; (4)speleogens (e.g., cupolas, slots, ceiling channels, spongework,rugged phreatic morphology especially along slots) indicateascending speleogenesis in deep phreatic to phreatic environments;(5) they exhibit poor relation to the present landscape;in some of them fluvial sediments are completely missing inspite of surface rivers/streams in the direct vicinity; (6) strongepiphreatic re-modelling is common in general (e.g., subhorizontalpassages arranged in cave levels, water-table flat ceilingsand notches) and related to the evolution of the recent landscape;(7) recharge structures and correlate surface precipitatesare poorly preserved or completely missing (denuded) on thepresent surface in spite of fact that recent recharges broadlyprecipitate travertines; (8) caves can be, and some of them are,substantially older than the recent landscape (Pliocene, Miocene),and (9) caves were formed in conditions of slow water ascent, which differentiate the process from faster vauclusianascending speleogenetical models. Any of described caves containsclear diagnostic features of real hypogene caves. There aremissing evidences that at least heated groundwaters took partduring speleogenesis of studied caves, nevertheless, somewhatincreased water temperature can be expected during speleogenesisat least in some of caves. Any of described caves cannotbe directly characterized as product of thermal waters or hydrothermalprocess (i.e. as real hyperkarst sensu Cigna 1978),therefore they do not represent hypogenic caves.


MODELLING THE EVOLUTION OF KARST AQUIFERS IN THREE DIMENSIONS/Conceptual models and realistic scenarios Inaugural dissertation/ zur Erlangung des Doktorgrades Dr. rer. nat. am Fachbereich Geowissenschaften im Institut fur Geologische Wissenschaften der Fr, 2013,
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Hiller, Thomas

This work presents the development of three dimensional karst evolution models for various settings and conditions. As karst aquifers are very sensitive to changes of their hydraulic boundary conditions a comprehensive understanding of the governing processes inside a karst aquifer is indispensable. Especially if a karst aquifer is inuenced by anthropogenic utilization like e.g. the construction of a dam site, the resulting changes inside the aquifer need to be understood as good as possible to prevent any unpredictable incidents. The use of numerical models to simulate the development of a karst aquifer is therefore a suitable tool in the preliminary investigations. It will be shown that simple three dimensional damsite models can be used to evaluate the parameters that control the karst aquifer evolution. Based on these simple models an enhanced three dimensional model of a real damsite is developed. This model is used to simulate the evolution of the aquifer close to this damsite and to expose how the construction of the dam inuenced the nearby bedrock signicantly. It is shown that the karstied zone around the dam site is the reason for the subsidence of an adjacent highway. The presented numerical results can be veried by eld observations. Additionally to the damsite models a three dimensional model approach is presented that describes the formation of large collapse dolines. Collapse dolines are signicant surface features of karst landscapes and their evolution which is usually linked to a subsurface karst system is of high interest in the karst community. To simulate the evolution and interaction of such a doline system, a three dimensional model with several spatially distributed dolines is used. There, based on the concept of a mechanically weakened crushed zone, the evolution over time is presented. The applied collapsing mechanism used in this work also allows to estimate the bedrock removal and surface lowering over time. The determined rates are in good agreement with values reported in literature


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