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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 scale is 1. a very thin and flat rock fragment [16]. 2. the accumulation of precipitated solid material. 3. the ratio of prototype to model dimensions. 4. the ratio of the length between any two points on a map, plan or section to the actual distance between the same points on the ground or in a cave [25].?

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Karst environment, Culver D.C.
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Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
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Your search for conduit flow (Keyword) returned 72 results for the whole karstbase:
Showing 16 to 30 of 72
Karstic groundwater flow characteristics in the Cretaceous Chalk aquifer, Northern Ireland, 1999, Barnes S,
The Cretaceous Chalk in Northern Ireland (Ulster White Limestone Formation) is a locally important aquifer for both public and private supply, yet little is known about its groundwater flow regime. This issue is important for the protection of existing groundwater abstractions and for the development of new sources as it will help determine groundwater vulnerability and resource potential in the Chalk. The subject has been addressed using hydrochemical variations from individual springs, together with artificial and natural water tracing techniques employed from river-sinks located at outcrop. A common orientation has been established between traced groundwater flow routes and the dominant northwest-southeast fracture trend within the Ulster White Limestone Formation. Hydraulic gradient has also been shown to have little significance in controlling the flow direction, suggesting poor fracture connectivity and thus extreme aquifer heterogeneity. Tracer breakthrough curve characteristics and velocities (up to 2838 metres per day) are indicative of conduit rather than fracture flow. In addition, the highly variable water chemistry associated with all the proven river-sink supplied springs has been independently classified to meet conduit flow criteria. Conversely, the much less variable water chemistry associated with springs draining Chalk subcrop areas (with no influence from river-sinks) is consistent with a less active karstic regime

Temperature as a natural tracer of short residence times for groundwater in karst aquifers, 1999, Martin J. B. , Dean R. W.
Chemistry of karst waters is controlled by reactions with aquifer rocks, the extent of mixing between water sources, and variations in the composition of recharged waterThe extent of reactions and mixing may be determined uniquely if compositions of both recharged and discharged water are known, such as where sinking streams are linked to resurgent springs, and if residence time in the subsurface can be measuredSuch a linked system occurs along the Santa Fe River in north-central Florida, where the river flows underground for approximately 52 km as it crosses from confined to unconfined portions of the Floridan AquiferTemporal variations in temperature can be correlated between the river sink, the river rise, and Sweetwater Lake, a karst window approximately midway between the sink and riseDelays in the arrival time of temperature maxima and minima from the sink to Sweetwater Lake and from Sweetwater Lake to the Rise reflect the residence time of the river water in the subsurfaceResidence time correlates with the river stage and ranges from approximately 12 hours to more than four days at high and low stage, respectively between the river sink and SweetwaterLake, and from about six hours to nearly two days at high and low stage, respectively, between Sweetwater Lake and the river riseThese short residence times reflect minimum flow rates of between 13 and 9 km/day, indicating conduit flowKnowing the residence time at any stage allows sampling of water as it enters the aquifer, and then again as it dischargesChanges in the chemistry of water as it passes through the subsurface should reflect chemical reactions, mixing, or both

A conceptual view of carbonate island karst, 1999, Mylroie J. E. , Vacher H. L.
Conceptually, the karst of carbonate islands can be modeled as the result of eogenetic diagenesis, freshwater/ saltwater mixing, and glacioeustasyThe resulting eogenetic karst occurs in small, youthful limestone islands where the evolution of the karst is concurrent with meteoric diagenesis of the host rock, which has never been out of the active circulation of meteoric waterThe rearrangement of the material of high porosity / low permeability sediments into moderate porosity / high permeability rock feeds back to the nature of the diagenetic environment as the flow volume of the lens is reduced by increasing flow efficiencyLimestone islands are a constrained and simple environment, defined as carbonate islands (no noncarbonate rock) and composite islands (mixture of carbonate and non carbonate rock)Simple carbonate islands lack noncarbonate rocks within the active hydrological zone; carbonate-cover islands contain a noncarbonate contact that limits the freshwater lens and deflects vadose flowThe type of island greatly influences the subsequent karst hydrologyIncreasing island size appears to cross a threshold favoring conduit flowThe karst features resulting from these island types, combined with mixing geochemistry and glacioeustasy, differ from those in continental settings and require a unique conceptual approach to modeling

Conduit hydrogeology of a tropical coastal carbonate aquifer. MSc thesis, 1999, Beddows, P. A

The aim of this study is to investigate the hydrogeology of the submerged conduit systems of a coastal carbonate aquifer (Caribbean coast, Yucatan Peninsula, Mexico), and thereby better understand their significance as large permeability heterogeneities. A complex spatial trend in conduit flow rates (determined by quantitative fluorescent dye tracing initiated 6 km inland) was found, including significant velocity variation between consecutive conduit segments. Elevated coastal velocities under low tide conditions are shown by salinity profiling, to be induced by the volumetric increase of discharging water from mixing with marine water. Semi-diurnal micro-tidal loading is sufficient to induce flooding from the sea into the conduits at one coastal discharge point, and significantly reduce flow rates at another. Furthermore, a network of four observation sites extending 5 km inland indicates efficient propagation of the ~0.30 m tidal signal through the Nohoch Nah Chich conduit system, a distance several time greater than previously appreciated in this environment. The field results clearly indicate that the hydrogeological flux is dominated by cavernous porosity, and that the aquifer is dynamically responsive to the high-frequency low-magnitude tidal loading to a significant distance inland. Conventional coastal groundwater models such as the Ghyben-Herzberg lens model, assume isotropic homogeneous equivalent-porous-medium conditions. Because the corollaries of the conventional models are inconsistent with the field evidence, they are inapplicable in this environment. It is hoped that these results will aid future modelling efforts, and improve our capacity to manage the valuable groundwater resources which represents the unique source of potable water to the local population.


Karst conduit flow and its hydrodynamic characteristics - Houzhai River drainage basin in Puding, Guizhou, China as an example, 2001, Wang L. C. , Zhang Y. Z. ,
Conduit flow is a special geomorphologic and hydrological phenomenon in karst area. Houzhai River drainage basin in Puding, Guizhou Province is a large-scale test field in the main and broad karst area in the southern part of China, where conduit flow is a general reserve and drainage system for groundwater. Based on the great deal of field investigation and indoor research work during the 1970s-1980s, pulse tests were done four times there during 1988-1991 in wet and dry seasons. It shows that water level at each observation site changes from 10 to 1800 mm, with the larger variation in upper stream and at karst windows than in lower reaches and at each exit along subterraneous rivers. The average flow velocity in conduit system is determined within 200 - 800 m/h, with the less change from flood to dry seasons, and it is higher in principal conduits and in upper stream area. Also, the reliable divided discharge ratio among each hydrological conduit of sunken system has been got. Thus, combined with detailed field survey in this area, the river system has been exposed finally

Depth of conduit flow in unconfined carbonate aquifers, 2001, Worthington Stephen R. H. ,
The locus of formation of cave conduits in carbonate aquifers is dependent on hydraulic, structural, and solubility factors, and these can facilitate flow deep below the water table. Geothermal heating results in increasing temperatures and decreasing viscosity with depth. This favors deep conduit development for flow paths with lengths >3 km. Steeply dipping strata aid the flow of undersaturated water to depth along bedding planes. These factors indicate that flow deep below the water table should be associated with steep dips and long flow paths. Empirical evidence strongly supports this model and demonstrates that the flow depth of conduits is directly proportional to flow-path length and stratal dip

24 h Tracer Tests on Diurnal Parameter Variability in a Subglacial Karst Conduit: Small River Valley, Canada., 2001, Ross Jh. , Serefiddin F. , Hauns M. , Smart C. C.
Repeated dye tracer tests were undertaken for two complete diurnal discharge cycles at Small River Glacier, British Columbia. The injection site is a well developed glacier moulin. Monitoring was done at a karst spring in a cave entrance 1530 m down valley. The spring is the major outlet of glacial meltwater and also drains karstified glacier forefields. High flow velocities and low dispersivities indicate a very well developed conduit flow system. Discharge and velocity show strong diurnal cycles and are controlled by the amount of meltwater. The relationship of increasing velocity with discharge is approximately linear. Dispersivity values do not show any significant variation under diurnal discharge cycles. These results show the importance of diurnal variation in a transient groundwater system.

Modeling flow in phreatic and epiphreatic karst conduits in the Holloch cave (Muotatal, Switzerland), 2001, Jeannin P. Y. ,
The Holloch cave is a site where the hydrodynamic behavior of a karst conduit network can be observed with a high degree of precision. Observed heads. discharge rates, conduit sizes, and conduit lengths have been compiled into a simple hydrodynamic model in order to check their consistency. It was possible to calibrate and satisfactorily fit the observed data. Model results show the following: (1) Flow models which are able to simulate turbulent flow in variably saturated conduit networks can adequately model conduit flow-dominated karst systems. (2) Karst systems may be strongly nonlinear, especially because of the presence of epiphreatic conduits. (3) Under certain circumstances, storage in the epiphreatic conduits and in the fissured limestone matrix can be neglected. (4) The typical effective hydraulic conductivity of karst conduits ranges between 1 and 10 m s(-1), and the Louis Formula is adequate to calculate head losses in those conduits. (5) Indirect measurements of flow velocity using scallop size indicate values of similar to 30-40% of the maximal annual discharge, and velocity derived from pebble size indicates values of similar to 150% of the maximal annual discharge

Depth of conduit flow in unconfined carbonate aquifers: comment., 2002, Ford D. C.

Depth of conduit flow in unconfined carbonate aquifers: Comment and Reply: COMMENT, 2002, Ford D,

Interaction of fracture and conduit flow in the evolution of karst aquifers, 2002, Romanov D. , Dreybrodt W. , Gabrovsek F.

Interaction of Fracture and Conduit Flow in the Evolution of Karst Aquifers, 2003, Romanov D. , Dreybrodt W. , Gabrovsek F.

Karst aquifers in their initial state consist of a net of fractures with largely differing aperture widths. As a most simple example we investigate the evolution of a karst aquifer where a wide fracture with aperture width A0 = 0.03 cm is embedded into a dense net of narrow fractures of aperture widths a0 < A0. The aim of this work is to investigate the influence of the hydraulic coupling between these fractures to the evolution of the karst aquifer. The modelling domain consists of a confined aquifer, which is divided into a square network consisting of narrow fractures. In its center a straight wide fracture leads from the input at hydraulic head h to the output at head zero. We have computed the breakthrough times of this aquifer as a function of a0. For a0 = 0 the breakthrough time is that of an isolated one-dimensional fracture. As a0 is increased the breakthrough times drop until at about a0 > 0.02 cm they are reduced significantly by almost one order of magnitude. This is caused by the following mechanism. As the central tube gets enlarged into a funnel like shape from its entrance water from its tip is injected into the fine net of fractures. Therefore more aggressive solution enters into the central fracture and enhances dissolutional widening there. By this way aquifers with wide fractures embedded into a continuum of fine fractures experience accelerated karstification.


Conceptual models for karstic aquifers, 2003, White, W. B.

Karstic carbonate aquifers are extremely heterogeneous with a distribution of permeability that spans many orders of magnitude. They often contain open conduit flow paths with hydraulic characteristics more like surface streams than ground water. Karstic carbonate aquifers have highly efficient interfaces with surface water through swallets and springs. Characterizing parameters include: area of ground-water basin, area of allogenic recharge basins, conduit carrying capacity, matrix hydraulic conductivity, fracture hydraulic conductivity, conduit system response time, and conduit/fracture coupling coefficients. The geologic setting provides boundary conditions that allow the generalized conceptual model to be applied to specific aquifers.


Hydrogeological overview of the Bure plateau, Ajoie, Switzerland, 2003, Kovacs A. , Jeannin P. Y. ,
This study presents a hydrogeological synthesis of the most recent data from the Bure plateau in Ajoie, canton Jura, NW Switzerland. Included is a complete reappraisal of aquifer geometry and aquifer boundaries, the delineation of catchment areas based on tracing experiments, and the evaluation of the hydraulic role of different hydrostratigraphic units. Furthermore, it presents GIS-based calculations on the mean piezometric surface, the thickness of the unsaturated zone and on the thickness of the minimum and mean saturated zones. The spatial extension of the shallow karst zone is also evaluated. A coherent conceptual model and the two-dimensional steady-state combined discrete channel and continuum type numerical model of the aquifer has been constructed. The research site is 83 km(2) in area and is underlain by slightly folded layers of Mesozoic limestones and marls. The Bure plateau is dissected by normal faults, which form a succession of elongated horst and graben structures. The main aquifer consists of Maim limestones, with thicknesses varying between zero (eastern border) and 320 m (south-eastern regions). The aquifer is bounded from below by the Oxfordian Marls. The underlying sediments of Middle Jurassic age are considered to be hydraulically independent. The surface topography of the Oxfordian Marls reveals the periclinal termination of a wide anticline over the plateau and a syncline in the southern parts. The aquifer contains three marly intercalations. Tracing experiments prove that marl layers do not act as regional aquicludes. These experiments also allow for the division of the aquifer surface into several water catchments. Based on tracing tests and piezometric data a NW-SE oriented groundwater divide seems to extend in the regions of Porrentruy-Bure-Croix. Calculations of the average (matrix flow) and minimum (conduit flow) water tables indicate an extended shallow karst zone in the region of Boncourt-Buix-St-Dizier. The thickness of the saturated zone increases towards the extremities of the research site, being thickest in the South. The thickness of the unsaturated zone shows a large variation, reaching its maximum in the central areas. Numerical model calculations roughly reproduce the observed hydraulic heads and mean spring discharges, they confirm current ideas about hydraulic parameters and suggest the existence of extended karst subsystems throughout the model domain

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

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