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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. ...

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Your search for effective porosity (Keyword) returned 9 results for the whole karstbase:
DOLOMITE-ROCK TEXTURES AND SECONDARY POROSITY DEVELOPMENT IN ELLENBURGER GROUP CARBONATES (LOWER ORDOVICIAN), WEST TEXAS AND SOUTHEASTERN NEW-MEXICO, 1991, Amthor Je, Friedman Gm,
Pervasive early- to late-stage dolomitization of Lower Ordovician Ellenburger Group carbonates in the deep Permian Basin of west Texas and southeastern New Mexico is recorded in core samples having present-day burial depths of 1.5-7.0 km. Seven dolomite-rock textures are recognized and classified according to crystal-size distribution and crystal-boundary shape. Unimodal and polymodal planar-s (subhedral) mosaic dolomite is the most widespread type, and it replaced allochems and matrix or occurs as void-filling cement. Planar-e (euhedral) dolomite crystals line pore spaces and/or fractures, or form mosaics of medium to coarse euhedral crystals. This kind of occurrence relates to significant intercrystalline porosity. Non-planar-a (anhedral) dolomite replaced a precursor limestone/dolostone only in zones that are characterized by original high porosity and permeability. Non-planar dolomite cement (saddle dolomite) is the latest generation and is responsible for occlusion of fractures and pore space. Dolomitization is closely associated with the development of secondary porosity; dolomitization pre-and post-dates dissolution and corrosion and no secondary porosity generation is present in the associated limestones. The most common porosity types are non-fabric selective moldic and vuggy porosity and intercrystalline porosity. Up to 12% effective porosity is recorded in the deep (6477 m) Delaware basin. These porous zones are characterized by late-diagenetic coarse-crystalline dolomite, whereas the non-porous intervals are composed of dense mosaics of early-diagenetic dolomites. The distribution of dolomite rock textures indicates that porous zones were preserved as limestone until late in the diagenetic history, and were then subjected to late-stage dolomitization in a deep burial environment, resulting in coarse-crystalline porous dolomites. In addition to karst horizons at the top of the Ellenburger Group, exploration for Ellenburger Group reservoirs should consider the presence of such porous zones within other Ellenburger Group dolomites

GROUND-WATER BEHAVIOR IN KARST - EXAMPLE OF THE OMBLA SPRING (CROATIA), 1995, Bonacci O,
The hydro-electric power plant (HEPP) which will exclusively use water from a karst underground storage basin will be built in the vicinity of the abundant karst spring Ombla in Croatia. This paper presents the results obtained by hydrogeologic, hydrologic and hydraulic investigations related to the principles of ground water circulation in the karst. The analyses included the determination of the effective porosity n(e) of the karst aquifer and the definition of the volume of large conduits and small fractures in the karst which form the aquifer volume. The position and dimensions of large karst conduits have also been defined. It was established that in three small springs, Zaton, Zavrelje and Slavljan, water overflows from the Ombla Spring in periods of high ground water levels, It was also discovered that at certain periods the Dupuit expression for steady-state flow in an unconfined aquifer can be used. In accordance with this, it was possible to determine the values of hydraulic conductivity, K (in m s(-1)), for the Ombla aquifer. They range from 2 x 10(-3) to 5 x 10(-3) m s(-1) and are inversely proportional to the Ombla Spring discharge. Continuous measurements of the ground water level by several piezometers located in the karst hinterland of the Ombla Spring and simultaneous measurement of the discharge made it possible to define discharge curves of the Ombla Spring dependent upon the ground water levels at Various locations. Characteristic features of the discharge curves made the identification of the position and dimensions of the main karst conduits possible

Bedding planes, moved bedding planes, connective fissures and horizontal cave passages (Examples from Postojnska Jama cave), 1998, Č, Ar Jož, E, Š, Ebela Stanka

In 3 examples of passage parts from Postojnska Jama their speleogenesis was studied. It was shown that they are formed along bedding planes, moved bedding planes and connective fissures. The advantage for speleogenesis of some bedding planes and moved bedding planes is represented with their connection into penetrative effective porosity in specific structural block.


Travel Times Along Selected Flow Paths of the Edwards Aquifer, Central Texas, 2001, Kuniansky E. L. , Fahlquist L. , Ardis A. F.

Flow path travel times in the structurally controlled, karstic Edwards aquifer were estimated using simulated ground-water levels obtained from a finite-element model. For this analysis, simulated monthly ground-water levels were averaged over an 11-year calibration period to minimize the transient effect of short-term recharge and discharge events. The 1978-89 calibration period was characterized by average to wetter-than-average climatic conditions; simulated water-level and spring-flow compared favorably with measured data. Flow paths for which travel times were estimated range from 1,250 to 10,000 feet wide and from about 8 to 180 miles long. Effective aquifer thickness and effective porosity can be highly variable and is poorly defined throughout most of the aquifer. Accordingly, travel-time estimates were computed within known or inferred thicknesses and porosities within known or inferred ranges of 350 to 850 feet and 15 to 35 percent, respectively. The minimum rock matrix porosity for each element was divided by 10 to estimate a minimum time of travel (a worst case time of travel). Travel times range from 14 to 160 years for a flow path from the Blanco River Basin to San Marcos Springs and from 350 to 4,300 years for a flow path from the West Nueces River Basin to Comal Springs. Travel times near the minimum of the ranges are similar in magnitude to those determined from tritium isotopes in spring water, thus supporting the hypothesis that effective porosity and effective thickness of the aquifer is less than the respective ranges. 


Discrimination of effective from ineffective porosity in heterogeneous Cretaceous carbonates, Al Ghubar field, Oman , 2003, Smith L. B. , Eberli G. P. , Masaferro J. L. , Aldhahab S.

The Natih E heavy-oil reservoir (21j API) atAl Ghubar field, Oman has produced less than 5% of the calculated oil in place. Porosity logs used to calculate reserves show high porosity throughout the reservoir, but further analysis of the only continuous core taken from the field indicates that much of the porosity is ineffective. There are four heavily oil-stained, high-permeability skeletalpelletal grainstone units with interparticle porosity in the core that probably contributed most of the production. The four permeable grainstone units occur at the top of small-scale accommodation cycles that have wackestone and packstone bases. These grainstones make up about 20% of the total thickness of the porous Natih E reservoir. The other 80% is composed of packstone and wackestone with ineffective microporosity, interparticle porosity in burrows, and isolated moldic and intraskeletal porosity. The small-scale reservoirbearing cycles can be correlated across the field using the separation between the medium and deep induction curves as a guide. Resistivity logs are the most reliable tool to distinguish effective from ineffective porosity. Most high-permeability grainstone units have deep induction values more than 100 ohmmand separation of more than 10 ohm m between the medium and deep induction curves. The ineffective intervals with microporosity, burrow porosity, and moldic porosity have lower resistivity and little separation between the medium and deep induction curves 


Investigation of the groundwater residence time distribution in the Aladag (Kayseri-Adana, Turkey) karstic aquifer. PhD Thesis, 2004, Ozyurt, N. Nur

The Aladað karstic aquifer of Eastern Taurids Range extends between 400m and 3750m elevations and, covers an area of 1900 km2 within Adana-Kayseri-Niðde provinces. The study covers the Kapuzbaþý, Göksu shallow circulation and Yerköprü 1, Yerköprü 2 and Yerköprü 3 deep circulation springs that extend from recharge area to the Zamanti river.
The system is fed by precipitation of Mediterranean origin and total precipitation input, evapo-transpiration, net recharge and its volumetric equivalent are found to be 1113 mm, 451 mm, 879 mm and 939 106 m3. Mean annual discharges of Yerköprü 3, Yerköprü 1 and 2, Göksu and, Kapuzbaþý and Barazama springs are 449 106 m3, 82 106 m3, 299 106 m3 and 146 106 m3. Noble gas ( 20Ne, 40Ar, 84Kr) and 18O isotopes suggest recharge area elevation and temperature ranges of 1700-2100m and 2-6 oC. The helium (He) content of groundwater increases with increasing circulation depth. Year round biweekly-monthly samples’ electrical conductivity, tritium ( 3H) and 18O content reveal that Kapuzbaþý and Göksu springs and, Yerköprü 1 and Yerköprü 2 springs behave similarly among themselves.
The “CFC model ages” of the springs where, chlorofluorocarbon (CFC) contents increased from 1997 to 2002, range between 10 to 20 years and 20 to 30 years in the shallow and deep circulation parts, respectively. The 3H/3He* absolute age of groundwater from springs is around 20 +/- 2.5 years. In the computer code LUMPEDUS that was developed for unsteady state lumped parameter modeling applications, 3H, tritiogenic helium-3 ( 3He*), CFC-11, CFC-12, CFC-113, and 18O were used as environmental tracers. Serially connected plug-exponential flow model applied to all springs. All models were calibrated for observed outflux and their forecasted 3H, 3He* and 18O time series were found to be in good agreement with the observations. Mean residence times found by models are in agreement with 3H/3He* ages. According to residence time distribution suggested by models, most of the discharges comprise recharges that occurred within last 20 to 30 years. Sixty per cent of discharge comprises recharges of the last 3 to 4 years. The active reservoir volumes of Yerköprü 1-2, Kapuzbaþý, Göksu and Yerköprü 3 springs are found to be 1604 106 m3, 2808 106 m3, 5728 106 m3 and 8609 106 m3 , respectively. According to well established linear relationship between reservoir volumes and discharge elevations, an active volume increases 50 106 m3 per 1m decrease in elevation. Cumulative active reservoir volume is found to be 18749 106 m3 at 450 m elevation where Yerköprü 3 spring is located. Uppermost elevation of active reservoir is located at 836m. Groundwater’s velocity ranges from 2.09 m/day to 5.57 m/day and the corresponding hydraulic conductivities for different reservoirs are between 41.8 m/day and 212.2 m/day. The ordering of hydraulic conductivity among springs ( > > > ) seems to be related to their time of formation. Based on an assumption of 1500m of maximum hydraulic head at the recharge area, the effective porosity of the system is estimated to be 0.86 per cent.


Assessing the Vulnerability of a Municipal Well Field to Contamination in a Karst Aquifer, 2005, Renken R. A. , Cunningham K. J. , Zygnerski M. R. , Wacker M. A. , Shapiro A. M. , Harvey R. W. , Metge D. W. , Osborn C. L. , Ryan J. N. ,
Proposed expansion of extractive lime-rock mines near the Miami-Dade County Northwest well field and Everglades wetland areas has garnered intense scrutiny by government, public, environmental stakeholders, and the media because of concern that mining will increase the risk of pathogen contamination. Rock mines are excavated to the same depth as the well field's primary producing zone. The underlying karst Biscayne aquifer is a triple-porosity system characterized by (1) a matrix of interparticle porosity and separate vug porosity; (2) touching-vug porosity that forms preferred, stratiform passageways; and, less commonly, (3) conduit porosity formed by thin solution pipes, bedding-plane vugs, and cavernous vugs. Existing ground-water flow and particle tracking models do not provide adequate information regarding the ability of the aquifer to limit the advective movement of pathogens and other contaminants. Chemical transport and colloidal mobility properties have been delineated using conservative and microsphere-surrogate tracers for Cryptosporidium parvum. Forced-gradient tests were executed by introducing conservative tracers into injection wells located 100 m (328 ft) from a municipal-supply well. Apparent mean advective velocity between the wells is one to two orders of magnitude greater than previously measured. Touching-vug, stratiform flow zones are efficient pathways for tracer movement at the well field. The effective porosity for a continuum model between the point of injection and tracer recovery ranges from 2 to 4 percent and is an order of magnitude smaller than previously assumed. Existing well-field protection zones were established using porosity estimates based on specific yield. The effective, or kinematic, porosity of a Biscayne aquifer continuum model is lower than the total porosity, because high velocities occur along preferential flow paths that result in faster times of travel than can be represented with the ground-water flow equation. Tracer tests indicate that the relative ease of contaminant movement to municipal supply wells is much greater than previously considered

SUPPORTIVE METHODS FOR ASSESSING EFFECTIVE POROSITY AND REGULATING KARST AQUIFERS, 2010, Stevanovic Z. , Milanovic S. & Ristic V.
Regulation of a karst aquifer implies engineering interventions designed to control its flow and manage its water reserves. One of the most important prerequisites for the feasibility and success of regulation projects is proper assessment of aquifer effective porosity (storativity) and accumulated groundwater reserves. This paper is focused on several specific methods which can contribute to a reliable assessment of the size and volume of effective storage in karst: cave diving survey, camera logging of cavities, stochastic analysis of discharge regime and 3D modelling of karst interior. The application of these methods on selected test sites in Montenegro, Algeria and Serbia are described. These methods were applied as part of the research programme conducted in the catchment of Mlava Spring, the largest spring in the Carpathian karst of Serbia. The results obtained by the stochastic analyses of the springs discharge regime, as well as siphon diving of the spring and 3D modelling for reconstruction of conduits networks in karst interior are particularly important.

Effective porosity of a carbonate aquifer with bacterial contamination: Walkerton, Ontario, Canada, 2012, Worthington S. R. H. , Smart C. C. , Ruland W.

Preferential flow through solutionally enlarged fractures can be a significant influence on travel times and source area definition in carbonate aquifers. However, it has proven challenging to step beyond a conceptual model to implementing, parameterizing and testing an appropriate numerical model of preferential flow. Here both porous medium and preferential flow models are developed with respect to a deadly contamination of the municipal groundwater supply at Walkerton, Ontario, Canada. The preferential flow model is based on simple orthogonal fracture aperture and spacing. The models are parameterized from bore hole, gamma, flow and video logs resulting in a two order of magnitude lower effective porosity for the preferential flow model. The observed hydraulic conductivity and effective porosity are used to predict groundwater travel times using a porous medium model. These model predictions are compared to a number of independent estimates of effective porosity, including three forced gradient tracer tests. The results show that the effective porosity and hydraulic conductivity values closely match the preferential flow predictions for an equivalent fracture network of _10 m spacing of 1 mm fractures. Three tracer tests resulted in groundwater velocities of hundreds of meters per day, as predicted when an effective porosity of 0.05% was used in the groundwater model. These velocities are consistent with a compilation of 185 tracer test velocities from regional Paleozoic carbonate aquifers. The implication is that carbonate aquifers in southern Ontario are characterized by relatively low-volume dissolutionally enlarged fracture networks that dominate flow and transport. The porous matrix has large storage capacity, but contributes little to transport. Numerical models based on much higher porosities risk significantly underestimating capture zones in such aquifers. The hydraulic conductivity – effective porosity prediction framework provides a general analytical frame work for a preferential flow carbonate aquifer. Not only is the framework readily parameterized from borehole observations, but also it can be implemented in a conventional porous medium model, and critically tested using simple tracer tests.


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