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 tidal river is a river strongly influenced and subject to tidal currents [16].?

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

What is Karstbase?

Search KARSTBASE:

keyword
author

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

Search in KarstBase

Your search for evapotranspiration (Keyword) returned 31 results for the whole karstbase:
Showing 16 to 30 of 31
Do woody plants affect streamflow on semiarid karst rangelands?, 2005, Wilcox B. P. , Owens M. K. , Knight R. W. , Lyons R. K. ,
There is considerable public and political pressure to reduce woody plant cover on rangelands as a means of increasing water yield, despite the lack of studies documenting that such a strategy is effective. In the Texas Hill Country, runoff from the Edwards Plateau recharges the highly productive and regionally vital Edwards Aquifer. The dominant woody plant on the Plateau is Ashe juniper (Juniperus ashei Buchholz). To understand how woody plant cover may affect the amount and timing of runoff in this region, we monitored streamflow from nine small (3- to 6-ha) watersheds over a 13-year period. After the first two years (initial observations), 100% of the shrub cover was removed from three of the watersheds and similar to70% from another three. Following these treatments we continued to monitor runoff for four years, suspended monitoring for four and a half years, and then resumed monitoring for an additional three years. Runoff from these nine first-order watersheds generally accounted for <5% of the total precipitation and occurred entirely as stormflow (there was no baseflow before or after treatment). Some runoff was generated as subsurface flow, as indicated by hydrographs showing prolonged runoff (typically lasting hours longer than the rainfall). We evaluated the influence of woody plant cover on streamflow by comparing streamflow during the four-year treatment period with that during the posttreatment period (when considerable recovery of woody plants had taken place). Our findings indicate that changes in woody plant cover had little influence on the amount, timing, or magnitude of streamflow from these watersheds. On the basis of this work and other observations in the region, we hypothesize that, for small watersheds, changes in shrub cover will have little or no effect on streamflow except where springs are present

Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia, PhD Thesis, 2005, Eberhard, S. M.

Groundwater is a significant component of the world’s water balance and accounts for >90 % of usable freshwater. Around the world groundwater is an important source of water for major cities, towns, industries, agriculture and forestry. Groundwater plays a role in the ecological processes and ‘health’ of many surface ecosystems, and is the critical habitat for subterranean aquatic animals (stygofauna). Over-abstraction or contamination of groundwater resources may imperil the survival of stygofauna and other groundwater-dependent ecosystems (GDEs). In two karst areas in Western Australia (Yanchep and Leeuwin-Naturaliste Ridge), rich stygofauna communities occur in cave waters containing submerged tree roots. These aquatic root mat communities were listed as critically endangered because of declining groundwater levels, presumably caused by lower rainfall, groundwater abstraction, and/or forest plantations. Investigation of the hydrology and ecology of the cave systems was considered essential for the conservation and recovery of these threatened ecological communities (TECs). This thesis investigated the hydrology and ecology of one of the TECs, located in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge. A multi-disciplinary approach was used to explore aspects pertinent to the hydrology and ecology of the groundwater system.
Thermoluminescence dating of the limestone suggested that development of the karst system dates from the Early Pleistocene and that caves have been available for colonisation by groundwater fauna since that time. Speleogenesis of the watertable maze caves occurred in a flank margin setting during earlier periods of wetter climate and/or elevated base levels. Field mapping and leveling were used to determine hydrologic relationships between caves and the boundaries of the karst aquifer. Monitoring of groundwater levels was undertaken to characterise the conditions of recharge, storage, flow and discharge. A hydrogeologic model of the karst system was developed.
The groundwater hydrograph for the last 50 years was reconstructed from old photographs and records whilst radiometric dating and leveling of stratigraphic horizons enabled reconstruction of a history of watertable fluctuations spanning the Holocene to Late Pleistocene. The watertable fluctuations over the previous 50 years did not exceed the range of fluctuations experienced in the Quaternary history, including a period 11,000 to 13,000 years ago when the watertable was lower than the present level.
The recent groundwater decline in Jewel Cave was not reflected in the annual rainfall trend, which was above average during the period (1976 to 1988) when the major drop in water levels occurred. Groundwater abstraction and tree plantations in nearby catchments have not contributed to the groundwater decline as previously suggested. The period of major watertable decline coincided with a substantial reduction in fire frequency within the karst catchment. The resultant increase in understorey vegetation and ground litter may have contributed to a reduction in groundwater recharge, through increased evapotranspiration and interception of rainfall. To better understand the relationships between rainfall, vegetation and fire and their effects on groundwater recharge, an experiment is proposed that involves a prescribed burn of the cave catchment with before-after monitoring of rainfall, leaf-area, ground litter, soil moisture, vadose infiltration and groundwater levels.
Molecular genetic techniques (allozyme electrophoresis and mitochondrial DNA) were used to assess the species and population boundaries of two genera and species of cave dwelling Amphipoda. Populations of both species were largely panmictic which was consistent with the hydrogeologic model. The molecular data supported the conclusion that both species of amphipod have survived lower watertable levels experienced in the caves during the Late Pleistocene. A mechanism for the colonization and isolation of populations in caves is proposed.
Multi Dimensional Scaling was used to investigate patterns in groundwater biodiversity including species diversity, species assemblages, habitat associations and biogeography. Faunal patterns were related to abiotic environmental parameters. Investigation of hydrochemistry and water quality characterized the ecological water requirements (EWR) of the TEC and established a baseline against which to evaluate potential impacts such as groundwater pollution.
The conservation status of the listed TEC was significantly improved by increasing the number of known occurrences and distribution range of the community (from 10 m2 to > 2 x 106 m2), and by showing that earlier perceived threatening processes (rainfall decline, groundwater pumping, tree plantations) were either ameliorated or inoperative within this catchment. The GDE in the Jewel Cave karst system may not have been endangered by the major phase of watertable decline experienced 1975-1987, or by the relatively stable level experienced up until 2000. However, if the present trend of declining rainfall in southwest Western Australia continues, and the cave watertable declines > 0.5 m below the present level, then the GDE may become more vulnerable to extinction.
The occurrence and distribution of aquatic root mat communities and related groundwater fauna in other karst catchments in the Leeuwin-Naturaliste Ridge is substantially greater than previously thought, however some of these are predicted to be threatened by groundwater pumping and pollution associated with increasing urban and rural developments. The taxonomy of most stygofauna taxa and the distribution of root mat communities is too poorly known to enable proper assessment of their conservation requirements. A regional-scale survey of stygofauna in southwest Western Australia is required to address this problem. In the interim, conservation actions for the listed TECs need to be focused at the most appropriate spatial scale, which is the karst drainage system and catchment area. Conservation of GDEs in Western Australia will benefit from understanding and integration with abiotic groundwater system processes, especially hydrogeologic and geomorphic processes.


Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia [abstract], 2006, Eberhard S. M.
This thesis investigates the hydrology and ecology of a threatened aquatic root mat community in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge, Western Australia. Development of the karst system dates from the Early Pleistocene and the caves have been available for colonisation by groundwater fauna since that time. Speleogenesis of the watertable maze caves occurred in a flank margin setting during earlier periods of wetter climate and/or elevated base levels. Watertable fluctuations over the last 50 years did not exceed the range experienced in the Quaternary history. The recent groundwater decline in Jewel Cave was not related to rainfall, nor groundwater abstraction nor nearby tree plantations. However, it did coincide with a reduction in fire frequency within the karst catchment. The resultant increase in understorey vegetation and ground litter may have reduced groundwater recharge through increased evapotranspiration and interception of rainfall. The populations of two genera and species of cave dwelling Amphipoda are largely panmictic. Both species have survived lower watertable levels during the Late Pleistocene. A mechanism for the colonization and isolation of populations in caves is proposed. Faunal patterns (including species diversity, species assemblages, habitat associations and biogeography) were related to abiotic environmental parameters. The ecological water requirements of the community were determined as a baseline for evaluation of impacts such as groundwater pollution. If rainfall continues to decline, and the cave watertable declines > 0.5 m below the present level, then the groundwater ecosystem may become more vulnerable to extinction. The taxonomy and distribution of root mat communities is poorly known and a regional-scale survey is required to properly assess their conservation requirements. Meanwhile, conservation actions for the communities need to be focused at the scale of the karst drainage system and catchment area.

Reversibility of forest conversion impacts on water budgets in tropical karst terrain, 2006, Chandler Dg,
A conceptual model of the control of tropical land use and vegetative cover on bedrock recharge is developed for highly permeable geologic substrates. A case study of water budgets is then developed from field data and simple modeling for upland sites with three different vegetative covers (cropland, intensively grazed pasture and forest regrowth) in Leyte, Philippines. Water budget model results show that annual precipitation is divided primarily between evapotranspiration and overland flow for the pasture, but apportioned more to evapotranspiration and inputs to bedrock storage for the crop and forest sites. Modeled evapotranspiration from the forest (1906 mm) was not sufficiently greater than that for either the crop (1661 mm) or pasture (1476 mm) sites to offset the greater overland flow from those sites. The differences in overland flow are related to depth profiles of soil bulk density, which decreased between crop and forest and increased between crop and pasture, and drainable porosity, which increased between crop and forest and decreased between crop and pasture. Dry season streamflow is assumed to be primarily base flow and dependent on wet season bedrock recharge, which was dramatically lower for the pasture (106 mm) than for the crop (1134 mm) or forest covers (1320 mm), for 2946 mm of rainfall. The results support the premise that for landscapes with adequate storage in bedrock fractures, forest regrowth can increase recharge to perched aquifers, and hence dry season baseflow, relative to cropping and that dramatic reductions in overland flow and increases in dry season baseflow may be achieved by reforestation of compacted pastures. (c) 2005 Elsevier B.V. All rights reserved

Extended Abstract: Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia, 2006, Eberhard, Stefan M.

This thesis investigates the hydrology and ecology of a threatened aquatic root mat community in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge, Western Australia. Development of the karst system dates from the Early Pleistocene and the caves have been available for colonisation by groundwater fauna since that time. Speleogenesis of the watertable maze caves occurred in a flank margin setting during earlier periods of wetter climate and/or elevated base levels. Watertable fluctuations over the last 50 years did not exceed the range experienced in the Quaternary history. The recent groundwater decline in Jewel Cave was not related to rainfall, nor groundwater abstraction nor nearby tree plantations. However, it did coincide with a reduction in fire frequency within the karst catchment. The resultant increase in understorey vegetation and ground litter may have reduced groundwater recharge through increased evapotranspiration and interception of rainfall. The populations of two genera and species of cave dwelling Amphipoda are largely panmictic. Both species have survived lower watertable levels during the Late Pleistocene. A mechanism for the colonization and isolation of populations in caves is proposed. Faunal patterns (including species diversity, species assemblages, habitat associations and biogeography) were related to abiotic environmental parameters. The ecological water requirements of the community were determined as a baseline for evaluation of impacts such as groundwater pollution. If rainfall continues to decline, and the cave watertable declines > 0.5 m below the present level, then the groundwater ecosystem may become more vulnerable to extinction. The taxonomy and distribution of root mat communities is poorly known and a regional-scale survey is required to properly assess their conservation requirements. Meanwhile, conservation actions for the communities need to be focused at the scale of the karst drainage system and catchment area.


Geochemical and statistical evidence of recharge, mixing, and controls on spring discharge in an eogenetic karst aquifer, 2009, Moore Paul J. , Martin Jonathan B. , Screaton Elizabeth J.

Information about sources of recharge, distributions of flow paths, and the extent of water–rock reactions in karst aquifers commonly result from monitoring spring chemistry and discharge. To investigate the relationship between spring characteristics and the complexities of karst aquifers, we couple variations in surface- and groundwater chemistry to physical conditions including river stage, precipitation, and  evapotranspiration (ET) within a sink-rise system through a 6-km portion of the Upper Floridan aquifer (UFA) in north-central Florida. Principal component analysis (PCA) of time series major-element compositions suggests that at least three sources of water affect spring discharge, including allogenic recharge into a swallet, diffuse recharge through a thin vadose zone, and water upwelling from deep within the aquifer. The deep-water source exerts the strongest influence on water chemistry by providing a majority of Na+, Mg2+, K+, Cl, and SO2 4 to the system. Anomalously high temperature at one of several monitoring wells reflects vertical flow of about 1 m/year. Mass-balance calculations suggest diffuse recharge and deep-water upwelling can provide up to 50% of the spring discharge; however, their contributions depend on head gradients between the conduit and surrounding aquifer matrix, which are influenced
by variations in precipitation, ET, and river stage. Our results indicate that upwelling from deep flow paths may provide significant contributions of water to spring discharge, and that monitoring only springs limits interpretations of karst systems by masking critical components of the aquifer, such as water sources and flow paths. These results also suggest the matrix in eogenetic aquifers is a major pathway for flow even in a system dominated by conduits.


Time‐lapse microgravity surveys reveal water storage heterogeneity of a karst aquifer, 2010, Jacob T. , Bayer R. , Chery J. , Le Moigne N.

Time‐lapse microgravity surveying combined with absolute gravity measurements is  used to investigate water storage changes in a karst aquifer of ∼100 km2 area. The survey  consists of 40 gravity stations measured with a relative gravimeter; absolute gravity is  measured at three stations for each survey. In total, four gravity surveys are performed over  a 2 year time period during consecutive wet and dry periods. Survey precisions range  between 2.4 and 5 mGal, enabling statistically significant detection of 10 mGal change, i.e.,  ∼0.25 m equivalent water level change. Observed gravity changes are coherent between  consecutive survey periods, i.e., net water withdrawal and net water recharge is observed,  reaching changes as high as 22 mGal. Observed gravity changes allow refining  evapotranspiration estimates, which may serve to improve the water budget of the aquifer.  High‐and low‐gravity amplitude zones characterize the karst system, demonstrating  spatially variable storage behavior. Geomorphologic considerations are invoked to explain  the location of preferential zones of water storage, and a conceptual model of water storage  is discussed for the studied karst. 


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.


Biodiversity and conservation of subterranean fauna fromPortuguese karst. Ph.D. Thesis, 2012, Ana Sofia Reboleira

This research is a contribution to the study of subterranean biodiversity in karst areas of Portugal, towards its conservation.

The relative inaccessibility of the subterranean environment is a challenge for the study of its fauna, often accessible only in caves but more widely distributed. The subterranean animals are among the most rare, threatened and worldwide underprotected, often by the simple fact of being unknown.

Karst areas of Portugal occupy a considerable part of the territory and harbor more than 2000 caves. The complex biogeographical history of the Iberian Peninsula allowed the survival of several relict arthropod refugees in the subterranean environment.

Subterranean invertebrates have been ignored, as for as the protection of karst systems are concerned in Portugal, largely because knowledge was scarce and disorganized. Reviewing all the bibliographic sources about subterranean fauna from Portugal and listing troglobiont and stygobiont species and locations, was essential to understand the state of knowledge of species richness and the biogeography and conservation status for the studied areas.

In order to understand subterranean biodiversity patterns in karst areas from Portugal, one year of intense fieldwork was performed in more than 40 caves from 14 karst units. Several new species for science were discovered and 7 taxa comprising 2 new genera and 5 new species were described.

Bearing in mind that spatial distribution of subterranean species is crucial to ecological research and conservation, the distribution of hypogean species, from Portuguese karst areas, was mapped using geographic information systems. Also, its subterranean richness was compared with other areas of the world and missing species were estimated on a regional scale. The subterranean biodiversity patterns were analyzed, and several factors were tested to explain richness patterns. Evapotranspiration and the consequent high productivity on the surface may be determinant in the species richness in the different karst units of Portugal, but the depth of the caves and the unique geological features of every massif seemed to play a more important role.

In order to evaluate the tolerance of organisms to groundwater contamination, the acute toxicity of two substances were tested on stygobiont crustaceans with different degrees of troglomorphism. Our study showed that the high levels of endemism contribute to remarkably different toxicological responses within the same genus.

The major problems related to conservation of subterranean habitats were associated to direct destruction and their contamination. These ecosystems lack of specific protection, implying an adequate management of surface habitats and the establishment of priority areas. Integrating all the previous information, this study establishes a ranking of sites for conservation of subterranean fauna in karst areas of Portugal.This research is a contribution to the study of subterranean biodiversity in karst areas of Portugal, towards its conservation.

The relative inaccessibility of the subterranean environment is a challenge for the study of its fauna, often accessible only in caves but more widely distributed. The subterranean animals are among the most rare, threatened and worldwide underprotected, often by the simple fact of being unknown.

Karst areas of Portugal occupy a considerable part of the territory and harbor more than 2000 caves. The complex biogeographical history of the Iberian Peninsula allowed the survival of several relict arthropod refugees in the subterranean environment.

Subterranean invertebrates have been ignored, as for as the protection of karst systems are concerned in Portugal, largely because knowledge was scarce and disorganized. Reviewing all the bibliographic sources about subterranean fauna from Portugal and listing troglobiont and stygobiont species and locations, was essential to understand the state of knowledge of species richness and the biogeography and conservation status for the studied areas.

In order to understand subterranean biodiversity patterns in karst areas from Portugal, one year of intense fieldwork was performed in more than 40 caves from 14 karst units. Several new species for science were discovered and 7 taxa comprising 2 new genera and 5 new species were described.

Bearing in mind that spatial distribution of subterranean species is crucial to ecological research and conservation, the distribution of hypogean species, from Portuguese karst areas, was mapped using geographic information systems. Also, its subterranean richness was compared with other areas of the world and missing species were estimated on a regional scale. The subterranean biodiversity patterns were analyzed, and several factors were tested to explain richness patterns. Evapotranspiration and the consequent high productivity on the surface may be determinant in the species richness in the different karst units of Portugal, but the depth of the caves and the unique geological features of every massif seemed to play a more important role.

In order to evaluate the tolerance of organisms to groundwater contamination, the acute toxicity of two substances were tested on stygobiont crustaceans with different degrees of troglomorphism. Our study showed that the high levels of endemism contribute to remarkably different toxicological responses within the same genus.

The major problems related to conservation of subterranean habitats were associated to direct destruction and their contamination. These ecosystems lack of specific protection, implying an adequate management of surface habitats and the establishment of priority areas. Integrating all the previous information, this study establishes a ranking of sites for conservation of subterranean fauna in karst areas of Portugal.


Environmental Hydrogeological Study of Louros watershed, Epirus, Greece, 2012, Konstantina Katsanou

The present study aims to describe and characterize the Ionian zone karst formation concerning the karstification grade of carbonate formations and the development of aquifers, through the hydrogeological study of Louros River drainage basin, considering hydrological, hydrogeological and meteorological data, as well as major, trace element, rare earth element and isotope concentrations. It also aims to investigate basic karst properties such as storativity, homogeneity, infiltration coefficients and the parameters of the Louros basin hydrological balance.

To accomplish this aim daily discharge measurements obtained from Public Power Corporation at the Pantanassa station during the years 1956-1957, along with random discharge measurements from 15 springs along the basin performed by IGME between the years 1979-1989, daily meteorological data from 18 stations and 18 sets of potentiometric surface measurements from 38 sites were compiled. Additionally, chemical analyses on major and trace element concentrations of 42 rock samples and of five sets of water samples from 64 sampling sites, along with fourteen sets of successive periods in order to study the seasonal variation in the chemical composition of 11 springs and REE concentrations of 116 water samples. Moreover isotope ratios from 129 rain samples collected at five different altitudes, 331 samples of surface and groundwater samples, radon measurements on 21 groundwater samples and microbiological on 46 samples of surface and groundwater were evaluated. Daily runoff and random spring discharge missing data were completed applying the SAC-SMA and MODKARST simulation algorithms and the values of these parameters for the duration of the research (2008-2010) were predicted. The accuracy of the predicted values was tested applying statistical methods but also against observed values from in situ measurements performed during the same period (2008-2010).

Louros River drainage basin is located at the southern part of Epirus and covers an area of 953 km2. It is elongated and together with the adjacent basin of River Arachthos they constitute the major hydrographic systems discharging in the Amvrakikos Gulf. The main morphological features of the basin are elongated mountain ranges and narrow valleys, which are the result of tectonic and other geological processes mainly controlled by the limestone-“flysch” alternations. The length of the river’s major channel, which is parallel to the major folding direction (NNW-SSE), is 73.5 km. The mountainous part of the hydrogeological basin covers an area of 400 km2 and its endpoint was set at the Pantanassa station, where discharge measurements are performed. The underground limits of the basin coincides with the surface one, defined by the flysch outcrops at the western margin of the Ziros-Zalongo fault zone to the South, the application of isotope determinations and hydraulic load distribution maps at the North and East.

Geologically, Louros River drainage basin is composed of the Ionian zone formations. Triassic evaporites constitute the base of the zone overlain by a thick sequence of carbonate and clastic sedimentary rocks deposited from the Late Triassic to the Upper Eocene. In more detail, from base to top, the lithostratigraphical column of the zone includes dolomite and dolomitic limestone, Pantokrator limestone, Ammonitico Rosso, Posidonia Shales, Vigla limestone, Upper Senonian limestone, Palaeocene-Eocene limestone and Oligocene “flysch”. The major tectonic features of the regions are folds with their axes trending SW-NE at the northern part and NNW-SSE to NNE-SSW southern of the Mousiotitsa-Episkopiko-Petrovouni fault system and the strike-slip fault systems of Ziros and Petousi.

The evaluation of the daily meteorological data revealed that December is the most humid month of the year followed by January, whereas July and August are the driest months. Approximately 40-45% of the annual precipitation is distributed during the winter time and 30% during autumn. The mean annual precipitation ranges from 897.4 to 2051.8 mm and the precipitation altitude relationship suggests an increased precipitation with altitude at a rate of 84 mm/100 m. The maximum temperature is recorded during August and it may reach 40°C and the minimum during January. The temperature variation with the altitude is calculated at 0.61°C/100 m. The maximum solarity time is 377.8 h, recorded during July at the Arta station. December displays the highest relative humidity with a value of 84.2% recorded again at the Arta station. The highest wind velocity values are recorded at the Preveza station and similar velocities are also recorded at the Ioannina station. The real evapotranspiration in Louros drainage basin ranges between 27-39%. The potential evapotranspiration was calculated from the Ioannina station meteorological data, which are considered more representative for Louros basin, at 785.8 mm of precipitation according to Thornthwaite and at 722.0 mm according to Penman-Monteith.

According to the SAC-SMA algorithm the total discharge (surficial and underground) for the years 2008-2010 ranges between 61-73% of the total precipitation. The algorithm simulates the vertical percolation of rainwater in both unsaturated and saturated zones taking into account 15 parameters including the tension water capacity of the unsaturated zone, the maximum water storage capacity of both unsaturated and saturated zones, the water amount escaping into deeper horizons and not recorded at the basin’s outlet, the percentage of impermeable ground which is responsible for instant runoff, etc. These parameters are correlated to the hydrograph and are recalculated according to it. Two interesting aspects were pointed out from the discharge measurements and the algorithm application. The first is related to the maximum amount of free water, which can be stored at the basic flow of the karstic system, which is very high for the whole basin, reaching 1200 mm of precipitation and the second is the amount of water filtered to the deeper horizons, which reaches 0.098.

The discharge of individual karstic units was simulated applying the specialized MODKARST code. The code, which transforms precipitation to discharge resolving mathematical equations of non-linear flow using the mass and energy balance, successfully completed the time series of available data of spring discharge measurements for the period between the years 2008-2010.

Additionally, a number of useful parameters including spring recharge, delay period between precipitation and discharge, the storage capacity of the discharge area were also calculated by the MODKARST code. These data enabled the calculation of the annual infiltration coefficient for each one of the 15 springs and for the whole basin; the latter was found to range between 38-50% of annual precipitation. The total supply area was estimated approximately at 395 km2, which is consistent with the area of Louros hydrogeological basin calculated from hydrogeological data.

The 18 sets of water table measurements, each one corresponding to a different period, revealed that the aquifers of the intermediate part of Louros basin, which are developed in Quaternary alluvial sediments, are laterally connected to the carbonate formations of the individual karstic spring units, forming a common aquifer with a common water table.

Groundwater flow follows a general N-S direction from the topographic highs to the coastal area with local minor shifts to NE-SW and NW-SE directions. The artificial lake at the position of the Public Power Corporation’s Dam at the south of the region is directly connected to the aquifer and plays an important role in water-level variation. The water table contours display a higher gradient to the southern part due to the decreased hydraulic conductivity of the limestones close to Agios Georgios village. The decreased hydraulic conductivity is believed to be the reason for the development of the homonymous spring although the hydraulic load distributions suggest the extension of the aquifer to the south and a relation to the water level in Ziros Lake, boreholes and the Priala springs. The hydraulic gradient in the broader region ranges between 4-16‰. The absolute water level variation between dry and humid season ranges from 2 m at the South to 15-20 m to the North with an average of 9 m.

The hydrological balance of Louros River mountainous basin according to the aforementioned data is calculated as follows: The total precipitation between the years 2008-2010 ranged between 5.67E+08-9.8E+08 m3 and the discharge at Pantanassa site between 3.47E+08-6.83E+08 m3. The real evapotransiration ranged between 29-39% of the precipitation. The total discharge (runoff and groundwater) accounted for 61-73% of the precipitation, whereas the basic flow due to the percolation ranged between 34-38%. Considering a mean water level variation of 9 m, between the dry and humid season, the water amount constituting the local storage is 2025Ε+07 m3.

Statistical evaluation on spring discharge data and the recession curves analysis revealed three distinct levels with diverse karstic weathering along Louros basin coinciding to the upper, intermediate and low flow of Louros River, respectively. The developed karstic units are generally complex but simple individual units develop as well. The response of spring discharge to the stored water amounts is immediate but with relatively large duration suggesting the storage of large quantities of water and a well-developed system of karstic conduits, which however has not yet met its complete evolution. The karst spring’s units are homogeneous and each one is distinguished from different recession coefficients.

The three levels of flow are also distinguished from the duration curves, which point to individual units upstream, complex units receiving and transmitting water to the adjacent ones in the middle part and complex that only receive water from the upper. This distinguishment is also enhanced by the groundwater’s major ion concentrations, which reveal Ca-HCO3 water-type upstream, along with the isotopic composition at the same part. The prevalent Ca-HCO3-Cl-SO4 water-type in the middle part, the Na-Ca-Cl-SO4 water-type downstream and isotope variation confirms this distinguishment. Moreover, REE variation is also consistent with the three levels. The assumption of relatively large stored water reserves, which contribute to analogous “memory” of spring karstic units, as pointed out by autocorreletion functions is enhanced from SAC-SMA algorithm which premises an increased capacity at the lower zone of basic flow, as well as from the hydrochemical and isotopic composition of groundwater. Monitoring of the seasonal variation in groundwater composition revealed minor variations of hydrochemical parameters and remarkably stable isotopic composition. Both aspects can be explained by the existence of a considerable water body acting as a retarder to external changes.

The crosscorrelation functions suggest a well-developed karstic system, which however has not yet reached its complete maturity also confirmed from field observations. The same conclusion is extracted from the homogeneous evolution at the interval of each karstic unit as demonstrated from recession curves on spring hydrographs.

The results from hydrochemical analyses also revealed the effect of evaporitic minerals and phosphate-rich rocks in groundwater composition and confirmed the hydraulic relationships between surface and groundwater.

The study of the isotopic composition also contributed to exclude the potential connection between the Ioannina and Louros basins, confirmed the meteoric origin of groundwater and revealed the effect of seawater in the chemical composition of few sampling sites.

The microbiological research only revealed minor incidents of contamination and significant attenuation of microorganisms during periods of high discharge.


Biodiversity and conservation of subterranean fauna of Portuguese karst. Ph.D. thesis, 2012, Ana Sofia P. S. Reboleira

This research is a contribution to the study of subterranean biodiversity in karst areas of Portugal, towards its conservation.

The relative inaccessibility of the subterranean environment is a challenge for the study of its fauna, often accessible only in caves but more widely distributed. The subterranean animals are among the most rare, threatened and worldwide underprotected, often by the simple fact of being unknown.

Karst areas of Portugal occupy a considerable part of the territory and harbor more than 2000 caves. The complex biogeographical history of the Iberian Peninsula allowed the survival of several relict arthropod refugees in the subterranean environment.

Subterranean invertebrates have been ignored, as for as the protection of karst systems are concerned in Portugal, largely because knowledge was scarce and disorganized. Reviewing all the bibliographic sources about subterranean fauna from Portugal and listing troglobiont and stygobiont species and locations, was essential to understand the state of knowledge of species richness and the biogeography and conservation status for the studied areas.

In order to understand subterranean biodiversity patterns in karst areas from Portugal, one year of intense fieldwork was performed in more than 40 caves from 14 karst units. Several new species for science were discovered and 7 taxa comprising 2 new genera and 5 new species were described.

Bearing in mind that spatial distribution of subterranean species is crucial to ecological research and conservation, the distribution of hypogean species, from Portuguese karst areas, was mapped using geographic information systems. Also, its subterranean richness was compared with other areas of the world and missing species were estimated on a regional scale. The subterranean biodiversity patterns were analyzed, and several factors were tested to explain richness patterns. Evapotranspiration and the consequent high productivity on the surface may be determinant in the species richness in the different karst units of Portugal, but the depth of the caves and the unique geological features of every massif seemed to play a more important role.

In order to evaluate the tolerance of organisms to groundwater contamination, the acute toxicity of two substances were tested on stygobiont crustaceans with different degrees of troglomorphism. Our study showed that the high levels of endemism contribute to remarkably different toxicological responses within the same genus.

The major problems related to conservation of subterranean habitats were associated to direct destruction and their contamination. These ecosystems lack of specific protection, implying an adequate management of surface habitats and the establishment of priority areas. Integrating all the previous information, this study establishes a ranking of sites for conservation of subterranean fauna in karst areas of Portugal.This research is a contribution to the study of subterranean biodiversity in karst areas of Portugal, towards its conservation.

The relative inaccessibility of the subterranean environment is a challenge for the study of its fauna, often accessible only in caves but more widely distributed. The subterranean animals are among the most rare, threatened and worldwide underprotected, often by the simple fact of being unknown.

Karst areas of Portugal occupy a considerable part of the territory and harbor more than 2000 caves. The complex biogeographical history of the Iberian Peninsula allowed the survival of several relict arthropod refugees in the subterranean environment.

Subterranean invertebrates have been ignored, as for as the protection of karst systems are concerned in Portugal, largely because knowledge was scarce and disorganized. Reviewing all the bibliographic sources about subterranean fauna from Portugal and listing troglobiont and stygobiont species and locations, was essential to understand the state of knowledge of species richness and the biogeography and conservation status for the studied areas.

In order to understand subterranean biodiversity patterns in karst areas from Portugal, one year of intense fieldwork was performed in more than 40 caves from 14 karst units. Several new species for science were discovered and 7 taxa comprising 2 new genera and 5 new species were described.

Bearing in mind that spatial distribution of subterranean species is crucial to ecological research and conservation, the distribution of hypogean species, from Portuguese karst areas, was mapped using geographic information systems. Also, its subterranean richness was compared with other areas of the world and missing species were estimated on a regional scale. The subterranean biodiversity patterns were analyzed, and several factors were tested to explain richness patterns. Evapotranspiration and the consequent high productivity on the surface may be determinant in the species richness in the different karst units of Portugal, but the depth of the caves and the unique geological features of every massif seemed to play a more important role.

In order to evaluate the tolerance of organisms to groundwater contamination, the acute toxicity of two substances were tested on stygobiont crustaceans with different degrees of troglomorphism. Our study showed that the high levels of endemism contribute to remarkably different toxicological responses within the same genus.

The major problems related to conservation of subterranean habitats were associated to direct destruction and their contamination. These ecosystems lack of specific protection, implying an adequate management of surface habitats and the establishment of priority areas. Integrating all the previous information, this study establishes a ranking of sites for conservation of subterranean fauna in karst areas of Portugal.


Karst in deserts, 2013, Webb J. A. , White S.

Hot deserts are characterized by low mean annual rainfall (o250 mm, o1000) and very high evapotranspiration, so karst processes are inhibited. However, karst features are abundant and well developed in many deserts around the world. Salt caves occur predominantly in this environment and develop rapidly despite the arid climate, because they are formed mainly by rare, but intense, rain events. Deserts also preserve, relatively unaltered, gypsum and carbonate karst that formed in prior wetter climates or by hypogene processes. Carbonate karst, which is the most common karst in hot deserts, is modified very slowly by desert processes, including dissolution and salt crystallization, which fragments bedrock and speleothems


Karst aquifer average catchment area assessment through monthly water balance equation with limited meteorological data set: Application to Grza spring in Eastern Serbia, 2013, Vakanjac Vesna Ristić, Prohaska Stevan, Dušan Polomčić, Blagojević Borislava, Vakanjac Boris

In the absence of detailed exploration of karstic catchments, the calculation of available reserves and elements of the water balance equation frequently reflect the topographic size of the catchment area, and not the actual, active (underground) size. The two differ largely where karst is concerned. The paper deals with the problem of average catchment area size estimation in the situation when meteorological data are limited to precipitation and temperature, but discharge records are available for long period. Proposed methodology was applied to, calibrated, and validated on 15 karst springs in Serbia. Results obtained with the model differ up to 20% from hydrogeological exploration results. One of investigated springs is Grza karst spring, which belongs to the karstic formation of Kučaj and Beljanica (the Carpatho­Balkanide Arch of Eastern Serbia). In this paper, we used the Grza Spring to show model application and necessary improvements to progress from graphoanalytical to analytical model. The average catchment area is linked to the model parameter that reduces potential to real evapotranspiration on monthly bases. The model potential lies in the possibility to determine not only catchment area, but real evapotranspiration and dynamic volume of the porous ­ karst groundwater storage as well.


Using hydrogeochemical and ecohydrologic responses to understand epikarst process in semi-arid systems, Edwards plateau, Texas, USA, 2013, Schwartz Benjamin F. , Schwinning Susanne, Gerrard Brett, Kukowski Kelly R. , Stinson Chasity L. , Dammeyer Heather C.

The epikarst is a permeable boundary between surface and subsurface environments and can be conceptualized as the vadose critical zone of epigenic karst systems which have not developed under insoluble cover. From a hydrologic perspective, this boundary is often thought of as being permeable in one direction only (down), but connectivity between the flow paths of water through the epikarst and the root systems of woody plants means that water moves both up and down across the epikarst. However, the dynamics of these flows are complex and highly dependent on variability in the spatial structure of the epikarst, vegetation characteristics, as well as temporal variability in precipitation and evaporative demand. Here we summarize insights gained from working at several sites on the Edwards Plateau of Central Texas, combining isotopic, hydrogeochemical, and ecophysiological methodologies. 1) Dense woodland vegetation at sites with thin to absent soils (0-30 cm) is in part supported by water uptake from the epikarst. 2) However, tree transpiration typically becomes water-limited in dry summers, suggesting that the plant-available fraction of stored water in the epikarst depletes quickly, even when sustained cave drip rates indicate that water is still present in the epikarst. 3) Flow paths for water that feeds cave drips become rapidly disconnected from the evaporation zone of the epikarst and out of reach for plant roots. 4) Deep infiltration and recharge does not occur in these systems without heavy or continuous precipitation that exceeds some threshold value. Thresholds are strongly correlated with antecedent potential evapotranspiration and rainfall, suggesting control by the moisture status of the epikarst evapotranspiration zone. The epikarst and unsaturated zone in this region can be conceptualized as a variably saturated system with storage in fractures, matrix porosity, and in shallow perched aquifers, most of which is inaccessible to the root systems of trees, although woody vegetation may control recharge thresholds.


Physical Structure of the Epikarst, 2013, Jones, William K.

Epikarst is a weathered zone of enhanced porosity on or near the surface or at the soil/bedrock contact of many karst landscapes. The epikarst is essentially the upper boundary of a karst system but is also a reaction chamber where many organics accumulate and react with the percolating water. The epikarst stores and directs percolating recharge waters to the underlying karst aquifers. Epikarst permeability decreases with depth below the surface. The epikarst may function as a perched aquifer with a saturated zone that transmits water laterally for some distance until it drains slowly through fractures or rapidly at shaft drains or dolines. Stress-release and physical weathering as well as chemical dissolution play a role in epikarst development. Epikarst may be found on freshly exposed carbonates although epikarst that develops below a soil cover should form at a faster rate due to increased carbon dioxide produced by vegetation. The accumulation of soil within the fractures may create plugs that retard the downward movement of percolating water and creates a reservoir rich in organic material. The thickness of the epikarst zone typically ranges from a few meters to 15 meters, but vertical weathering of joints may be much deeper and lead to a “stone forest” type of landscape. Some dolines are hydrologically connected directly to the epikarst while other dolines may drain more directly to the deeper conduit aquifer and represent a “hole” in the epikarst. water stored in the epikarst may be lost to evapotranspiration, move rapidly down vertical shafts or larger joints, or drain out slowly through the soil infillings and small fractures. Much of the water pushed from the epikarst during storms is older water from storage that is displaced by the new event water.


Results 16 to 30 of 31
You probably didn't submit anything to search for