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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 exsurgence is 1. a term used to explain the re-emergence at the surface, as a stream, of meteoric water which has fallen entirely upon and percolated through a calcareous massif [19]. 2. a spring or seep in karstic terrane not clearly connected with swallets a higher level. synonyms: (french.) exsurgence; (german.) karstquelle, austrittbtelle; (greek.) karstiki pighi; (italian.) risorgente carsica; (russian.) karstovy istochnik; (spanish.) exsurgencia; (turkish.) yuzeyde blirme; (yugoslavian.) vrelo, obrh. see also emergence; resurgence.?

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Chemistry and Karst, White, William B.
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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 solute transport (Keyword) returned 24 results for the whole karstbase:
Showing 16 to 24 of 24
Epikarst storage in a karst aquifer: a conceptual model based on isotopic data, Milandre test site, Switzerland, 2003, Perrin K. , Jeannin P. Y. , Zwahlen F. ,
The Milandre test site is a karst aquifer characterized by diffuse infiltration, a well developed conduit network, and several tributaries feeding an underground river. Field data include discharge rate measurements, stable isotopes, weekly rainfall and spring-water isotope sampling, and detailed isotope sampling during three flood events. Flood sampling was carried out at several tributaries corresponding to conduit flow, vadose flow and seepage flow. Weekly sampling showed a strong buffering of the rainfall isotopic signal at the spring. This attenuation suggests an important mixing reservoir in the system. Flood events showed highly peaking hydraulic responses but buffered rain isotope responses. These results indicate that the soil and epikarst sub-systems have an important storage capacity. A conceptual model of flow and transport in the soil and epikarst zone is proposed: Soil plays an important role in mixing due to the presence of capillary water storage. Consequently dampened concentrations reach the epikarst despite a rapid hydraulic response. The epikarst acts as the storage element and distributes water as either a base flow component or a quick flow component. When recharge exceeds a given threshold, excess infiltrated water bypasses the soil and epikarst and reaches the saturated zone as fresh flow. Based on this model, the significance of phreatic storage is thought to be limited, at least in Milandre test site. Hence the saturated zone is seen mainly as a transmissive zone through its well developed conduit network. (C) 2003 Elsevier B.V. All rights reserved

A conceptual model of flow and transport in a karst aquifer based on spatial and temporal variations of natural tracers, 2003, Perrin, Jerome

Karst aquifers represent an important groundwater resource world-wide. They are highly vulnerable to contamination due to fast transport through the system and limited attenuation of contaminants. The two main hydrogeological approaches developed for studying flow and transport are: inference of the
system structure from karst spring hydrographs and chemographs; numerical modelling of flow and transport using a theoretical distribution of flow and transport field parameters. These two approaches lack of validation by detailed field measurements and observations. The main objective of this thesis is to “fill the gap” existing between field and model data. Observations of flow and transport parameters at several locations within the system were used to develop a conceptual model. This model was then compared to the existing models.
The main field test site is the Milandre karst aquifer, located in the Swiss tabular Jura. Natural tracers (major ions, oxygen-18, specific conductance) and discharge were measured on the underground river, its main tributaries, percolation waters, and the main spring. These data were collected on a long-term basis in order to assess the spatial variability of the parameters, and on a short time scale (i.e. flood events) in order to investigate the dynamic processes. Complementary sites (Brandt and Grand Bochat) were used for more observations at the base of the epikarst.
The proposed conceptual model considers four sub-systems: the soil zone, the epikarst, the unsaturated zone, and the phreatic zone. Each has its own specificity with respect to flow and transport. The soil zone controls the actual infiltration into the system. It contributes efficiently to groundwater storage. It mixes quickly stored water with fresh infiltrated water. Its thickness determines land-use: thick soils are generally cultivated whereas thin soils are under forested areas. The solutes concentration of soil waters depends on land-use for pollution-related parameters (nitrate, chloride, sulfate, potassium, sodium). Moreover the soil zone is the main source of CO2 which controls the limestone dissolution-related parameters. The epikarst zone contributes largely to groundwater storage. It distributes groundwater into vadose flow through conduits, and base flow through low permeability volumes (LPV) in the unsaturated zone. It is the sub-system where dissolution-related parameters are mostly acquired.
The unsaturated zone is seen as a transmissive zone connecting the epikarst to the horizontal conduit network of the phreatic zone. In case of flood events, some dissolution still occurs in this sub-system.
The phreatic zone is the partly flooded conduit network draining groundwater to the spring. It collects waters issued from the unsaturated zone, mixes the tributaries, and drain the water towards the discharge area. The role of phreatic storage appears to be limited for both hydraulics and transport.
Tributary mixing is a prominent process that shapes spring chemographs during flood events. In steady-state conditions, base flow is mainly sustained by the epikarst reservoir. Tracer concentrations are stable as the chemical equilibrium is already reached in the epikarst. Waters issued from the different tributaries mix in the conduit network, and the spring chemistry is the result of this mixing.
During flood events, transient flow induces non-linear mixing of the tributaries. The respective contributions of the tributaries change throughout the flood, and the spring chemographs vary accordingly. In case of important recharge, waters issued from other sources than the epikarst participate to the flood. First, soil water reaches the phreatic zone. Its characteristics are a dampened isotopic signal, and ionic concentrations differing from those of the epikarst. Second, fresh water directly issued from rainfall, may reach the phreatic zone. Its characteristics are a varying isotopic signal, and diluted ionic concentrations. The mixing components participating to the flood are controlled by the actual infiltration volume (or height). The limestone dissolution process is effective for the fresh and soil components of flow. However mixing processes play a more important role than dissolution for shaping the spring chemographs.
From a practical point of view, the project confirmed the prominent role of the soil zone and the epikarst on the solute transport in karst systems. This was already integrated in karst vulnerability mapping methods recently developed (EPIK, PI, VULK).

http://doc.rero.ch/record/2604/files/these_PerrinJ.pdf


Forecasting Versus Predicting Solute Transport in Solution Conduits for Estimating Drinking-Water Risks, 2004, Field, Malcolm S.

Contaminant releases in karstic terranes can cause rapid and devastating affects on drinking-water supplies. Because future contaminant releases are likely it is necessary that local water managers develop release scenarios so as to be prepared prior to an actual contaminant release occurring. Release scenarios may be forecasted using appropriate historical data or they may be predicted using selected measured parameters. Forecasting contaminant releases to drinking-water supplies in karstic terranes is best accomplished by conducting numerous tracer tests from each potential source location to each exposure point so that acceptable solute-transport parameters for each solution conduit may be estimated from analyses of the breakthrough curves. Compositing the numerous breakthrough curves and fitting a quintic spline allows development of a single representative breakthrough curve that may then be used to forecast the effects of a release. Predicting contaminant releases is accomplished by combining basic measured field parameters for selected solution conduits in functional relationships for application in solute-transport models. The resulting breakthrough curve and solute-transport parameters can be used to predict the effects of a release. The forecasting and prediction methodologies were tested using a hypothetical release into a solution conduit developed in a karstic aquifer. Both methods were shown to produce reasonably acceptable results. The prediction methodology produced better time-of-travel results and better mass recovery and exposure concentration results than did the forecasting methodology.


Analysis of karst hydrodynamics through comparison of dissolved and suspended solids transport, 2005, Valdes D. , Dupont J. P. , Laignel B. , Rodet J. ,
In karst systems, rain events often result in a decrease of the conductivity (a tracer of dissolved phase transport) and an increase in turbidity (a tracer of suspended solids transport) at wells and springs. This study shows that the comparison of suspended solids and solute transport by the coupled approach of T-C curves (Turbidity-Conductivity) and autocorrelations gives evidence of the transport processes in the karst network and allows understanding the karst hydrodynamics. To cite this article: D. Valdes et al., C. R. Geoscience 337 (2005). (c) 2005 Academie des sciences. Published by Elsevier SAS. All rights reserved

Investigation of Morphology Hydrogeology Relations in Harmanköy Beyyayla (Bilecik, Turkey) Karst System, PhD thesis, 2005, Aydin, H.

Harmanköy – Beyyayla Karst System (HBKS) forms the highlands in the Central Sakarya Basin. HBKS which is made of Jurassic Bilecik limestone is located within the province boundaries of Bilecik and Eskişehir and extends over a surface area of 49.5 km2. In this study, the HBKS whose boundary conditions are well defined was investigated in terms of morphology – hydrogeology relationships. Within this context, hydrogeological conceptual model of the study area was developed based on the physical parameters such as geology, tectonic, morphology and dynamic properties such as precipitation regime, infiltration, recharge, flow and storage.
Upon the evaluation of morphological, hydrologic, hydrogeological and hydrodynamic properties, it was concluded that HBKS consists of three distinct subsystems, namely the Beyyayla, Döşkaya and Nardın subsystems. It was further determined that Beyyayla and Döşkaya subsystems are similar by the properties mentioned above, while the Nardın subsystem differs from these two subsystems.
Recharge in HBSK occurs in two different forms; allogenic-point and autogenic-diffuse. Surface waters which are drained from Paleozoic age granites located in Beyyayla and Döşkaya subsystems’ recharge these systems as allogenic-point from Beyyayla and Tozman sinkholes. On the other hand, precipitation which falls on the limestone rock-mass supplies the autogenic diffuse recharge to the systems. Recharge to the Nardın subsystem on the other hand, is autogenic diffuse from direct precipitation on to the limestone area. The Qmax/Qmin ratio and the variation coefficient (CV) of chemical compositions of the springs which drain these subsystems, imply that concentrated flow is dominant in all these three systems. In addition, trace experiments carried out in Beyyayla and Döşkaya subsystems suggest that the flow is turbulent and rapid within the well-developed karstic channels. Advective-dispersive transport is controlling the solute transport in the system.
It was speculated that the energy gradient is more important than tectonic, lithologic characteristics and climatic changes in karst evolution Beyyayla and Döşkaya subsystems. Lowering of erosion base caused exposure of granites which consequently supplied the allogenic-point recharge to these subsystems. This was resulted in distinct morphologic, hydrologic and hydrodynamic properties of the subsystem.
Advisor: Assoc. Prof. Dr. Mehmet EKMEKÇİ, Hacettepe University, Department of Geological Engineering, Hydrogeological Engineering Division


EXAMINING A COUPLED CONTINUUM PIPE-FLOW MODEL FOR GROUNDWATER FLOW AND SOLUTE TRANSPORT IN A KARST AQUIFER, 2010, Hu B. X.
A coupled continuum pipe-flow (CCPF) model has been developed for groundwater flow and solute transport in a karst aquifer with conduits. Groundwater flow in conduits is simulated through a pipe flow model and flow in fissured matrix rock is described by Darcys law. Water mass exchange between the two domains is modeled by a firstorder exchange rate method. In this study, we investigate mathematical well-posedness (mathematical term, which means solution existence and uniqueness) of the CCPF model, develop a finite elementary method to numerically approximate the mathematical model and study the convergence of the numerical method. The study results prove the modeling approach is mathematically well posed and numerically converged. To study the accuracy of the CCPF model, a recently developed Stokes-Darcy (SD) model and CCPF model are compared with laboratory experimental results. It was found that the SD model simulations match well with experimental results, but the CCPF model overestimates the hydraulic head in the matrix, especially around the matrix and conduit interface. The model underestimates solute transport in the conduit and does not capture the plume distribution in the matrix. In comparison with the SD model, the CCPF model requires an additional parameter, the first-order mass exchange rate, and the parameter is normally obtained through inverse method curve fitting. The SD method may provide an approach to directly estimate the parameter value.

The initial stages of cave formation: Beyond the one-dimensional paradigm, 2011, Szymczak Piotr, Ladd Anthony J. C.

The solutional origin of limestone caves was recognized over a century ago, but the short penetration length of an undersaturated solution made it seem impossible for long conduits to develop. This is contradicted by field observations, where extended conduits, sometimes several kilometers long, are found in karst environments. However, a sharp drop in the dissolution rate of CaCO3 near saturation provides a mechanism for much deeper penetration of reactant. The notion of a “kinetic trigger” – a sudden change in rate constant over a narrow concentration range – has become a widely accepted paradigm in speleogenesis modeling. However, it is based on one-dimensional models for the fluid and solute transport inside the fracture, assuming that the dissolution front is planar in the direction perpendicular to the flow. Here we show that this assumption is incorrect; a planar dissolution front in an entirely uniform fracture is unstable to infinitesimal perturbations and inevitably breaks up into highly localized regions of dissolution. This provides an alternative mechanism for cave formation, even in the absence of a kinetic trigger. Our results suggest that there is an inherent wavelength to the erosion pattern in dissolving fractures, which depends on the reaction rate and flow rate, but is independent of the initial roughness. In contrast to one-dimensional models, two-dimensional simulations indicate that there is only a weak dependence of the breakthrough time on kinetic order; localization of the flow tends to keep the undersaturation in the dissolution front above the threshold for non-linear kinetics.

Research Highlights
- A kinetic trigger is not a prerequisite for limestone cave formation. - The added spatial dimension has a larger impact on breakthrough times than a kinetic trigger. - Planar dissolution front in a fracture is unstable to infinitesimal perturbations. - The most unstable wavelength depends on reaction kinetics and flow rate. - The instability leads to the formation of rapidly advancing, wormhole-like channels.


Solute transport in solution conduits exhibiting multi-peaked breakthrough curves, 2012, Field M. S. , Leij F. J.

Solute transport in karst aquifers is primarily constrained to solution conduits where transport is rapid, turbulent, and relatively unrestrictive. Breakthrough curves generated from tracer tests are typically positively-skewed and may exhibit multiple peaks. In order to understand the circumstances under which multi-peaked positively skewed breakthrough curves occur, physical experiments utilizing singleand multiple-flow channels were conducted. Experiments also included waterfalls, short-term solute detention in pools, and flow obstructions. Results demonstrated that breakthrough curve skewness nearly always occurs to some degree but is magnified as immobile-flow regions are encountered. Multi-peaked breakthrough curves occurred when flow in the main channel became partially occluded from blockage in the main channel that forced divergence of solute into auxiliary channels and when waterfalls and detention in pools occurred. Currently, multi-peaked breakthrough curves are fitted by a multi-dispersion model in which a series of curves generated by the advection–dispersion equation are fitted to each measured peak by superimposing the measured breakthrough curve to obtain a combined model fit with a consequent set of estimated velocities and dispersions. In this paper, a dual-advection dispersion equation with first-order mass transfer between conduits was derived. The dual-advection dispersion equation was then applied to the multi-peaked breakthrough curves obtained from the physical experiments in order to obtain some insight into the operative solute-transport processes through the acquisition of a consequent set of velocities, dispersions, and related parameters. Successful application of the dual-advection, dispersion equation to a tracer test that exhibited dual peaks for a karst aquifer known to consist of two connected but mostly separate conduits confirmed the appropriateness of using a multi-dispersion type model when conditions warrant.


Influence of conduit network geometry on solute transport in karst aquifers with a permeable matrix, 2013, Ronayne, M. J.

In karst aquifers with significant matrix permeability, water and solutes are exchanged between the conduits and carbonate matrix. Transport through the matrix increases thes pread of solutes and increases travel times. This study numerically evaluates advective solute transport in synthetic karst systems that contain 3D branching conduit networks. Particle tracking is performed to analyze the spatial and temporal transport history of solute that arrives at the conduit outlet. Three measures of transport connectivity are used to quantify the solute migration behavior: the skew ness of the particle arrival time distribution, the normalized fifth percentile of arrival times, and the fraction of the total travel time that occurs within conduits. All three of these metrics capture the influence of conduit network geometry on solute transport. A more tortuous network leads to enhanced conduit-matrix mixing, which reduces the transport connectivity and yields a broader distribution of solute arrival times. These results demonstrate that the conduit network geometry is an important control on solute transport in karst systems with a permeable matrix.


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