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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 hydraulic conductivity is 1. a proportionality constant relating hydraulic gradient to specific discharge which for an isotropic medium and homogeneous fluid, equals the volume of water at the existing kinematic viscosity that will move in unit time under a unit hydraulic gradient through a unit area measured at right angles to the direction of flow [22]. 2. the volume of water that will move through a medium in a unit of time under a unit hydraulic gradient through a unit area measured perpendicular to the direction of flow [22]. 3. the ability of a rock unit to conduct water under specified conditions [10]. it is typically expressed as gpd/ft2, ft/day, or m/day.?

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Your search for seawater intrusion (Keyword) returned 11 results for the whole karstbase:
Interpretation of groundwater level monitoring results in karst aquifers: examples from the Dinaric karst, 2000, Bonacci O, Rojebonacci T,
The paper presents an attempt to determine the characteristics of karst aquifers using information on groundwater lever (GWL) in natural holes and boreholes with different data quantity and time resolution of GWL measurements. In this paper the particulars of karst aquifers were analysed for four examples from the Dinaric karst. In all four study areas, aquifers are formed in bare, deep and well-developed Dinaric karst consisting of Cretaceous limestones. The first example represents a wide area of Imotsko polje in the karst. The aquifer was analysed on the basis of infrequent water level monitoring in natural karst water features (jamas, lakes, wells) and discharges of springs and rivers. The karst aquifer in this example is complex, non-homogenous and variable in space and time, which is frequent in the Dinaric karst. Regardless of the aforementioned it was possible to determine its elementary characteristics. The second example represents 10 wells used for the water supply for the city of Pula. The GWL and salinity were measured once a week in the period between 1981 and 1996. Even though these measurements were relatively infrequent in space and time, they served as bases for assessment of average and maximum aquifer conditions as well as boundaries of saltwater intrusion. In the third example only a portion of aquifer of the karst spring Blaz, which is in the contact with the Adriatic Seas, has been analyzed. It is a spring with an intrusion of salt water. For purposes of study of saltwater intrusion, 26 piezometers were drilled in its vicinity in which GWL, salinity and temperature were measured once a day during 168 days, a period comprising one complete cycle of seawater intrusion and retreat. These measurements proved the existence of dispersed discharge from the aquifer into the sea and its non-homogeneity in space. In the fourth example GWL was measured continuously in 10 deep (up to 300 m) piezometers in the hinterland of the Ombla Spring catchment. The measurement period lasted 2 years (January 1988 to December 1989). The analyses are made with hourly data. The results made it possible to determine numerous characteristics of the karst aquifer and a significant non-homogeneity of groundwater distribution in karst aquifers, depending more on the underground karst phenomena than the surface karst forms

Pollution by seawater intrusion into a karst system: new research in the case of the Almyros source (Heraklio, Crete, Greece), 2000, Arfib Bruno, De Marsily Ghislain, Ganoulis Jacques

Saline intrusion in karstic coastal aquifers is a common phenomenon which affects the quantity and quality of the freshwater resource. This paper examines the case of the Almyros system at Heraklio in Crete (Greece), characterized by a vast recharge area (300 km2) and a single brackish spring. Data from the Almyros spring and the surrounding wells are analyzed and a specific configuration of the karstic system is proposed. The evolution in time and space of the water temperature and chloride content is shown to be conditioned by the complex structure of this system and the heterogeneity of the karstic formations. These two parameters are analyzed and two storage zones are identified which generate different types of saline pollution. The water in the Almyros spring is not directly connected to the surrounding water-table aquifer. An inland reservoir far from the coast stores the cold, freshwater recharged in the mountains and supplies the Almyros spring. The pollution occurs during the transfer of the water toward the spring, through karstic conduits. Moreover, the local coastal aquifer is polluted by a generalized saline intrusion into the fractured matrix of the limestone, increased by withdrawals. Furthermore, the wells are contaminated by preferential saltwater flow through karstic channels reaching the seawater intrusion zone. The case of the Almyros system shows: (a) that a karstic coastal spring is not necessarily indicative of saline intrusion into the system; (b) that in optimal groundwater resource management, the whole hydrogeological system should be taken into account.


Coastal karst springs in the Mediterranean basin : study of the mechanisms of saline pollution at the Almyros spring (Crete), observations and modelling, 2002, Arfib B, De Marsily G, Ganoulis J,
Variations in salinity and flow rate in the aerial, naturally salty spring of Almyros of Heraklion on Crete were monitored during two hydrological cycles. We describe the functioning of the coastal karstic system of the Almyros and show the influence of the duality of the flow in the karst (conduits and fractured matrix) on the quality of the water resource in the coastal area. A mechanism of saltwater intrusion into this highly heterogeneous system is proposed and validated with a hydraulic mathematical model, which describes the observations remarkably well. Introduction. - Fresh groundwater is a precious resource in many coastal regions, for drinking water supply, either to complement surface water resources, or when such resources are polluted or unavailable in the dry season. But coastal groundwater is fragile, and its exploitation must be made with care to prevent saltwater intrusion as a result of withdrawal, for any aquifer type, porous, fractured or karstic. In karstic zones, the problem is very complex because of the heterogeneous nature of the karst, which makes it difficult to use the concept of representative elementary volume developed for porous or densely fractured systems. The karstic conduits focus the major part of the flow in preferential paths, where the water velocity is high. In coastal systems, these conduits have also an effect on the distribution of the saline intrusion. As was shown e.g. by Moore et al. [1992] and Howard and Mullings [1996], both freshwater and salt-water flow along the fractures and conduits to reach the mixing zone, or the zone where these fluids are superposed in a dynamic equilibrium because of their differences in density ; but the dynamics of such a saltwater intrusion are generally unknown and not represented in models. Such coastal karstic systems are intensely studied at this moment in the Mediterranean region [Gilli, 1999], both as above sea-level or underwater springs, for potential use in areas where this resource would be of great value for economic development. This article discusses the freshwater-saltwater exchange mechanisms in the karstic aquifer of the Almyros of Heraklion aquifer (Crete) and explains the salinity variations observed in the spring. First, the general hydrogeology of the study site is described, then the functioning of the spring : a main conduit drains the freshwater over several kilometres and passes at depth through a zone where seawater is naturally present. The matrix-conduit exchanges are the result of pressure differences between the two media. These processes are represented in a mathematical model that confirms their relevance. General hydrogeology of the studied site. - The karstic coastal system of the Almyros of Heraklion (Crete) covers 300 km2 in the Ida massif whose borders are a main detachment fault, and the Sea of Crete in the north, the Psiloritis massif (highest summit at 2,456 m) in the south and west, and the collapsed basin of Heraklion filled in by mainly neo-geneous marl sediments in the east. The watershed basin consists of the two lower units of characteristic overthrust formations of Crete (fig. 1) : the Cretaceous Plattenkalk and the Cretaceous Tripolitza limestones. The two limestone formations are locally separated by interbedded flysch or phyllade units that form an impervious layer [Bonneau et al., 1977 ; Fassoulas, 1999] and may lead to different flow behaviour within the two karstic formations. Neo-tectonic activity has dissected these formations with large faults and fractures. The present-day climate in Crete is of Mediterranean mountain type, with heavy rain storms and snow on the summits in winter. Rainfall is unevenly distributed over the year, with 80 % of the annual total between October and March and a year-to-year average of 1,370 mm. The flow rate of the spring is high during the whole hydrologic cycle, with a minimum in summer on the order of 3 m3.s-1 and peak flow in winter reaching up to 40 m3.s -1. The water is brackish during low flow, up to a chloride content of 6 g.l-1, i.e. 23 % of seawater, but it is fresh during floods, when the flow rate exceeds 15 m3.s-1. During the 1999-2000 and 2000-2001 hydrologic cycles, the water was fresh during 14 and 31 days, respectively. The water temperature is high and varies very little during the year (see table I). In the areas of Keri and Tilissos (fig. 1), immediately south of the spring, the city of Heraklion extracts water from the karstic system through a series of 15 wells with depth reaching 50 to 100 m below sea level. Initially, when the wells were drilled, the water was fresh, but nowadays the salinity rises progressively, but unequally from well to well (fig. 2). The relatively constant temperatures and salinities of the wells, during the hydrological cycle, contrast with the large salinity variations at the spring (fig. 2 and table I). They show that the karstic system is complex and comprises different compartments, where each aquifer unit reacts to its individual pressures (pumping, rainfall) according to its own hydrodynamic characteristics [Arfib et al., 2000]. The Almyros spring seems disconnected from the surrounding aquifer and behaves differently from that which feeds the wells (upper Tripolitza limestone). It is recharged by fresh water from the mountains, which descends to depths where it probably acquires its salinity. The spring would thus be the largest resource of the area, if it was possible to prevent its pollution by seawater. A general functioning sketch is proposed (fig. 3), which includes the different geological units of interest. Identification of the functioning of the Almyros spring through monitoring of physical and chemical parameters. - The functioning of the aquifer system of the Almyros spring was analysed by monitoring, over two hydrological cycles, the level of the spring, the discharge, the electric conductivity and the temperature recorded at a 30 min time interval. In the centre of the watershed basin, a meteorological station at an altitude of 800 m measures and records at a 30 min time interval the air temperature, rainfall, relative humidity, wind velocity and direction ; moreover, an automatic rain gauge is installed in the northern part of the basin at an altitude of 500 m. The winter floods follow the rhythm of the rainfall with strong flow-rate variations. In contrast, the summer and autumn are long periods of drought (fig. 7). The flow rate increases a few hours after each rainfall event ; the water salinity decreases in inverse proportion to the flow rate a few hours to a few days later. Observations showed that the water volume discharged at the Almyros spring between the beginning of the flow rate increase and the beginning of the salinity decrease is quite constant, around 770,000 m3 (fig. 4) for any value of the flow rate, of the salinity and also of the initial or final rainfall rates. To determine this constant volume was of the upmost importance when analyzing the functioning of the Almyros spring. The lag illustrates the differences between the pressure wave that moves almost instantaneously through the karst conduit and causes an immediate flow rate increase after rainfall and the movement of the water molecules (transfer of matter) that arrives with a time lag proportionate to the length of the travel distance. The variation of the salinity with the flow rate acts as a tracer and gives a direct indication of the distance between the outlet and the seawater entrance point into the conduit. In the case of the Almyros, the constant volume of expelled water indicates that sea-water intrusion occurs in a portion of the conduit situated several kilometres away from the spring (table II), probably inland, with no subsequent sideways exchange in the part of the gallery leading up to the spring. As the lag between the flow rate and the salinity recorded at the spring is constant, one can correct the salinity value by taking, at each time step, with a given flow rate, the salinity value measured after the expulsion of 770,000 m3 at the spring, which transforms the output of the system so as to put the pressure waves and the matter transfer in phase [Arfib, 2001]. After this correction, the saline flux at the spring, equal to the flow rate multiplied by the corrected salinity, indicates the amount of sea-water in the total flow. This flux varies in inverse proportion to the total flow rate in the high-flow period and the beginning of the low-flow period, thereby demonstrating that the salinity decrease in the spring is not simply a dilution effect (fig. 5). The relationship that exists between flow rate and corrected salinity provides the additional information needed to build the conceptual model of the functioning of the part of the Almyros of Heraklion aquifer that communicates with the spring. Freshwater from the Psiloritis mountains feeds the Almyros spring. It circulates through a main karst conduit that descends deep into the aquifer and crosses a zone naturally invaded by seawater several kilometers from the spring. The seawater enters the conduit and the resulting brackish water is then transported to the spring without any further change in salinity. The conduit-matrix and matrix-conduit exchanges are governed by the head differences in the two media. Mathematical modelling of seawater intrusion into a karst conduit Method. - The functioning pattern exposed above shows that such a system cannot be treated as an equivalent porous medium and highlights the influence of heterogeneous structures such as karst conduits on the quantity and quality of water resources. Our model is called SWIKAC (Salt Water Intrusion in Karst Conduits), written in Matlab(R). It is a 1 D mixing-cell type model with an explicit finite-difference calculation. This numerical method has already been used to simulate flow and transport in porous [e.g. Bajracharya and Barry, 1994 ; Van Ommen, 1985] and karst media [e.g. Bauer et al., 1999 ; Liedl and Sauter, 1998 ; Tezcan, 1998]. It reduces the aquifer to a single circular conduit surrounded by a matrix equivalent to a homogeneous porous medium where pressure and salinity conditions are in relation with sea-water. The conduit is fed by freshwater at its upstream end and seawater penetrates through its walls over the length L (fig. 6) at a rate given by an equation based on the Dupuit-Forchheimer solution and the method of images. The model calculates, in each mesh of the conduit and at each time step, the head in conditions of turbulent flow with the Darcy-Weisbach equation. The head loss coefficient {lambda} is calculated by Louis' formula for turbulent flow of non-parallel liquid streams [Jeannin, 2001 ; Jeannin and Marechal, 1995]. The fitting of the model is intended to simulate the chloride concentration at the spring for a given matrix permeability (K), depth (P) and conduit diameter (D) while varying its length (L) and its relative roughness (kr). The spring flow rates are the measured ones ; at present, the model is not meant to predict the flow rate of the spring but only to explain its salinity variations. Results and discussion. - The simulations of chloride concentrations were made in the period from September 1999 to May 2001. The depth of the horizontal conduit where matrix-conduit exchanges occur was tested down to 800 m below sea level. The diameter of the conduit varied between 10 and 20 m, which is larger than that observed by divers close to the spring but plausible for the seawater intrusion zone. The average hydraulic conductivity of the equivalent continuous matrix was estimated at 10-4 m/s. A higher value (10-3 m/s) was tested and found to be possible since the fractured limestone in the intrusion zone may locally be more permeable but a smaller value (10-5 m/s) produces an unrealistic length (L) of the saline intrusion zone (over 15 km). For each combination of hydraulic conductivity, diameter and depth there is one set of L (length) and kr (relative roughness) calibration parameters. All combinations for a depth of 400 m or more produce practically equivalent results, close to the measured values. When the depth of the conduit is less than 400 m, the simulated salinity is always too high. Figure 7 shows results for a depth of 500 m, a diameter of 15 m and a hydraulic conductivity of 10-4 m/s. The length of the saltwater intrusion zone is then 1,320 m, 4,350 m away from the spring and the relative roughness coefficient is 1.1. All the simulations (table II) need a very high relative roughness coefficient which may be interpreted as an equivalent coefficient that takes into account the heavy head losses by friction and the variations of the conduit dimensions which, locally, cause great head losses. The model simulates very well the general shape of the salinity curve and the succession of high water levels in the Almyros spring but two periods are poorly described due to the simplicity of the model. They are (1) the period following strong freshwater floods, where the model does not account for the expulsion of freshwater outside the conduit and the return of this freshwater which dilutes the tail of the flood and (2) the end of the low-water period when the measured flux of chlorides falls unexpectedly (fig. 5), which might be explained by density stratification phenomena of freshwater-saltwater in the conduit (as observed in the karst gallery of Port-Miou near Cassis, France [Potie and Ricour, 1974]), an aspect that the model does not take into account. Conclusions. - The good results produced by the model confirm the proposed functioning pattern of the spring. The regulation of the saline intrusion occurs over a limited area at depth, through the action of the pressure differences between the fractured limestone continuous matrix with its natural saline intrusion and a karst conduit carrying water that is first fresh then brackish up to the Almyros spring. The depth of the horizontal conduit is more than 400 m. An attempt at raising the water level at the spring, with a concrete dam, made in 1987, which was also modelled, indicates that the real depth is around 500 m but the poor quality of these data requires new tests to be made before any firm conclusions on the exact depth of the conduit can be drawn. The Almyros spring is a particularly favorable for observing the exchanges in the conduit network for which it is the direct outlet but it is not representative of the surrounding area. To sustainably manage the water in this region, it is essential to change the present working of the wells in order to limit the irreversible saline intrusion into the terrain of the upper aquifers. It seems possible to exploit the spring directly if the level of its outlet is raised. This would reduce the salinity in the spring to almost zero in all seasons by increasing the head in the conduit. In its present state of calibration, the model calculates a height on the order of 15 m for obtaining freshwater at the spring throughout the year, but real tests with the existing dam are needed to quantify any flow-rate losses or functional changes when there is continual overpressure in the system. The cause of the development of this karstic conduit at such a great depth could be the lowering of the sea level during the Messinian [Clauzon et al., 1996], or recent tectonic movements

Physical modelling of the seawater intrusion within a karst aquifer: the case of the Almyros of Heraklion (Crete), 2004, Arfib B, Ganoulis J,
Physical modelling of the seawater intrusion within a karst aquifer: the case of the Almyros of Heraklion (Crete). Coastal aquifers are subjected to natural seawater intrusion. Laboratory experiments were made to model the hydraulic conditions of saltwater inflow into a porous karstic conduit through which the freshwater flows. The conceptual model is based on the functioning scheme of the coastal karst system Almyros of Heraklion, Crete. The experiments show that seawater intrusion in a karst conduit can be diffuse, does not always lead to density separation of freshwater and seawater, and is not necessarily related to a conduit-network directly connected to the sea.

Modeling the salinity of an inland coastal brackish karstic spring with a conduit-matrix model, 2004, Arfib B, De Marsily G,
[1] The salinity of an inland coastal brackish karstic spring is modeled on the basis of a simple concept of fluid exchange through head differences between a continuous porous matrix and a karst conduit. The coastal aquifer is reduced to an equivalent porous medium ( matrix) naturally invaded by seawater, crossed by a single karst conduit where fresh water and brackish water mix in variable proportions and flow up into the spring. A new numerical model with an upwind explicit finite difference scheme, called salt-water intrusion in karst conduits (SWIKAC), was developed and successfully applied to the Almyros spring of Heraklio ( Crete, Greece). The good fit of the model to the observed salinity in the spring validates the proposed conceptual model of salinization. It provides a quantitative description of the seawater intrusion inside the karst conduit. The results open up new perspectives for managing the fragile and precious fresh water resources in karstic coastal zones

Contrle structural et tectonique sur lhydrogologie karstique du plateau Mahafaly (domaine littoral semi-aride, sud-ouest de Madagascar), 2005, Andr Grgoire, Bergeron Gilles, Guyot Luc
Structural and tectonic control on karstic hydrogeology of the plateau Mahafaly (semiarid coastal area, South-West of Madagascar) - The southwestern coast of Madagascar is characterized by a semiarid climate and low fresh water resources, which slow down the economic development. The studied area, located south of Toliara, is separated into a western coast of aeolian dunes and sandstones, where most of the people live, and the eastern, almost unoccupied, calcareous Mahafaly plateau. The coastal aquifer is dominated by salty water. The conductivity, close to 6000S/cm in the north, decreases to 3000S/cm in the south. The coastal plain is bordered to the East by highly karstified Cenozoic limestone, separated by a north-south cliff corresponding to the Toliara fault scarp. Surveys in coastal wells and in karstic aquifers clearly point out tidal influence on piezometric level and conductivity. In the north, the limestone cliff is directly in contact with the sea, whose water contaminates the karstic aquifer according to tidal variations. In the south, fresh water flows out on the beach by resurgences in the Quaternary sandstones, probably connected to the Eocene limestones, 5 km to the east. Drillings and exploration of some shafts on the plateau permitted access to the ground water table. It displays various conductivities ranging between 1500S/cm and 5000S/cm, unusually high for a karstic aquifer far away from the coast. The mapping of such conductivities suggests more complex phenomena than only marine intrusions into the different aquifer systems. Chemical and isotopic analyses show an obvious seawater intrusion and evaporation influence for the coastal aquifer. Iin the karstic aquifer, however, trace element analyses evoke contamination by upwelling of deep mineralized water. Salty water is frequent eastward on the basement and in the Mesozic formations. Today, fracture zones in both the coastal sandstones and in the Cenozoic limestone units control ground water circulations. Such fractures result from extensional phases in the past. The surface joint directions N-S, NE-SW and NW-SE reflect the deep-seated horst and graben structures. Microtectonic analyses give evidence of a post-Eocene WNW-ESE extension, and recent seismic data define an E-W extensional regime. The underground flowpaths are mostly on fractures oriented along the present stress field. The tectonic history in the area and the chemical composition of the waters suggest a connection of the karst aquifer with circulations from deep formations through deep-seated faults belonging to the Toliara fault system. This could explain abnormal salinities in the karstic system, far away from the coast.

Seawater intrusion in complex geological environments, 2005, Abarca Cameo, Elena

Modelling seawater intrusion (SWI) has evolved from a tool for understanding to a water management need. Yet, it remains a challenge. Difficulties arise from the assessment of dispersion coefficients and the complexity of natural systems that results in complicated aquifer geometries and heterogeneity in the hydraulic parameters. Addressing such difficulties is the objective of this thesis. Specifically, factors that may affect the flow and transport in coastal aquifers and produce heterogeneous salinity distributions are studied.

First, a new paradigm for seawater intrusion is proposed since the current paradigm (the Henry problem) fails to properly reproduce observed SWI wedges. Mixing is represented by means of a velocity dependent dispersion tensor in the new proposed problem. Thereby, we denote it as "dispersive Henry problem". SWI is characterized in terms of the wedge penetration, width of the mixing zone and influx of seawater. We find that the width of the mixing zone depends basically on dispersion, with longitudinal and transverse dispersion controlling different parts of the mixing zone but displaying similar overall effects. The wedge penetration is mainly controlled by the horizontal permeability and by the geometric mean of the dispersivities. Transverse dispersivity and the geometric mean of the hydraulic conductivity are the leading parameters controlling the amount of salt that enters the aquifer.

Second, the effect of heterogeneity was studied by incorporating heterogeneity in the hydraulic permeability into the modified Henry problem. Results show that heterogeneity causes the toe to recede while increases both the width and slope of the mixing zone. The shape of the interface and the saltwater flux depends on the distribution of the permeability in each realization. However, the toe penetration and the width of the mixing zone do not show large fluctuations. Both variables are satisfactorily reproduced, in cases of moderate heterogeneity, by homogeneous media with equivalent permeability and either local or effective dispersivities.

Third, the effect of aquifer geometry in horizontally large confined aquifers was analyzed. Lateral slope turned out to be a critical factor. Lateral slopes in the seaside boundary of more than 3% cause the development of horizontal convection cells. The deepest zones act as preferential zones for seawater to enter the aquifer and preferential discharging zones are developed in the upwards lateral margins. A dimensionless number, Nby, has been defined to estimate the relative importance of this effect.

All these factors can be determinant to explain the evolution of salinity in aquifers such as the Main aquifer of the Llobregat delta. Finally, a management model of this aquifer is developed to optimally design corrective measures to restore the water quality of the aquifer. The application of two different optimization methodologies, a linear and a non-linear optimization method, allowed (1) to quantify the hydraulic efficiency of two potential corrective measures: two recharge ponds and a seawater intrusion barrier; (2) to determine the water necessary to be injected in each of these measures to restore the water quality of the aquifer while minimizing changes in the pumping regime and (3) to assess the sustainable pumping regime (with and without the implementation of additional measures) once the water quality has been restored. Shadow prices obtained from linear programming become a valuable tool to quantify the hydraulic efficiency of potential corrective measures to restore water quality in the aquifer


Brackish springs in coastal aquifers and the role of calcite dissolution by mixing waters , 2007, Sanz Escud, Esteban

Brackish springs are relatively frequent phenomena in coastal carbonate formations and their existence has been extensively reported in Mediterranean coasts. In fact, more than 300 brackish springs have been identified only in the coast of the former Yugoslavia. They essentially consist of inland or submarine karst outlets discharging waters with flow-dependent salinity. The phenomenon is particularly surprising in inland springs, where high flow rates with significant salinities (presumablyBrackish springs are relatively frequent phenomena in coastal carbonate formations and their existence has been extensively reported in Mediterranean coasts. In fact, more than 300 brackish springs have been identified only in the coast of the former Yugoslavia. They essentially consist of inland or submarine karst outlets discharging waters with flow-dependent salinity. The phenomenon is particularly surprising in inland springs, where high flow rates with significant salinities (presumably


Review: The Yucatan Peninsula karst aquifer, Mexico , 2011, Bauergottwein Peter, Gondwe Bibi R. N. , Charvet Guillaume, Marin Luis E. , Rebolledovieyra Mario, Meredizalonso Gonzalo

The Yucatan Peninsula karst aquifer is one of the most extensive and spectacular karst aquifer systems on the planet. This transboundary aquifer system extends over an area of approximately 165,000 km2 in Mexico, Guatemala and Belize. The Triassic to Holocene Yucatan limestone platform is located in the vicinity of the North American/Caribbean plate boundary and has been reshaped by a series of tectonic events over its long geologic history. At the end of the Cretaceous period, the Yucatan Peninsula was hit by a large asteroid, which formed the Chicxulub impact crater. The Yucatan Peninsula karst aquifer hosts large amounts of groundwater resources which maintain highly diverse groundwater-dependent ecosystems. Large parts of the aquifer are affected by seawater intrusion. Anthropogenic pollution of the aquifer has been increasing over the past few decades, owing to relentless economic development and population growth on the Peninsula. This review summarizes the state of knowledge on the Yucatan Peninsula karst aquifer and outlines the main challenges for hydrologic research and practical groundwater-resources management on the Peninsula.


Review: The Yucatn Peninsula karst aquifer, Mexico, 2011, Bauergottwein P. , Gondwe B. R. N. , Charvet G. , Marn L. E. , Rebolledovieyra M. , Meredizalonso G.

The Yucatán Peninsula karst aquifer is one of the most extensive and spectacular karst aquifer systems on the planet. This transboundary aquifer system extends over an area of approximately 165,000 km2 in México, Guatemala and Belize. The Triassic to Holocene Yucatán limestone platform is located in the vicinity of the North American/Caribbean plate boundary and has been reshaped by a series of tectonic events over its long geologic history. At the end of the Cretaceous period, the Yucatán Peninsula was hit by a large asteroid, which formed the Chicxulub impact crater. The Yucatán Peninsula karst aquifer hosts large amounts of groundwater resources which maintain highly diverse groundwater-dependent ecosystems. Large parts of the aquifer are affected by seawater intrusion. Anthropogenic pollution of the aquifer has been increasing over the past few decades, owing to relentless economic development and population growth on the Peninsula. This review summarizes the state of knowledge on the Yucatán Peninsula karst aquifer and outlines the main challenges for hydrologic research and practical groundwater-resources management on the Peninsula


The mineral springs of the Scrajo spa (Sorrento peninsula, Italy): a case of natural seawater intrusion, 2013, Corniello A. , Trifuoggi M. , Ruggieri G.

This paper deals with the mineral springs feeding the Scrajo spa in the Sorrento peninsula southeast of Naples, approximately 6 km from Castellammare di Stabia, another spa location. The Scrajo mineral water is sulphureous, salt-bromine-iodic and CO2-rich. The two hydromineral areas fall within the groundwater basin of Mt. Faito formed chiefly by limestones. Due to the high permeability of the limestones, there is considerable rainwater infiltration which recharges a basal fresh groundwater resting on denser seawater. This groundwater body feeds the mineral springs of the Scrajo spa, the springs of Castellammare di Stabia and some submarine springs. All the data gathered for the Scrajo springs led to propose the following mineralisation scheme: (1) The basal fresh groundwater of Mt. Faito (on underlying seawater) receives endogenous contributions of CO2 and H2S which cause a ‘‘natural’’ seawater intrusion within the fresh groundwater; (2) The upwelling of gases would appear to occur via the major faults which bound Sorrento peninsula to the NW; (3) During the year, the chemistry of the springs changes according to different degrees of seawater intrusion: the minimum occurs in June and the maximum in November. The close interaction between the sea and the Scrajo’s mineral waters (but also those of Castellammare di Stabia) highlights their particular vulnerability not only to overextraction of groundwater but also to climate change. Finally, a hypothesis is presented to explain the connection between the mineral waters rich in CO2 and H2S and the concentration of karst phenomena observed in the Scrajo area.


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