The distinctive karstic, freshwater wetlands of the northern Caribbean and Central American region support the prolific growth of calcite-rich periphyton mats. Aside from the Everglades, very little research has been conducted in these karstic wetlands, which are increasingly threatened by eutrophication. This study sought to (i) test the hypothesis that water depth and periphyton total phosphorus (TP) content are both drivers of periphyton biomass in karstic wetland habitats in Belize, Mexico and Jamaica, (ii) provide a taxonomic inventory of the periphytic diatom species in these wetlands and (iii) examine the relationship between periphyton mat TP concentration and diatom assemblage at Everglades and Caribbean locations. Periphyton biomass, nutrient and diatom assemblage data were generated from periphyton mat samples collected from shallow, marl-based wetlands in Belize, Mexico and Jamaica. These data were compared to a larger dataset collected from comparable sites within Everglades National Park. A diatom taxonomic inventory was conducted on the Caribbean samples and a combination of ordination and weighted-averaging modeling techniques were used to compare relationships between periphyton TP concentration, periphyton biomass and diatom assemblage composition among the locations. Within the Everglades, periphyton biomass showed a negative correlation with water depth and mat TP, while periphyton mat percent organic content was positively correlated with these two variables. These patterns were also exhibited within the Belize, Mexico and Jamaica locations, suggesting that water depth and periphyton TP content are both drivers of periphyton biomass in karstic wetland systems within the northern Caribbean region. A total of 146 diatom species representing 39 genera were recorded from the three Caribbean locations, including a distinct core group of species that may be endemic to this habitat type. Weighted averaging models were produced that effectively predicted mat TP concentration from diatom assemblages for both Everglades (R2=0.56) and Caribbean (R2=0.85) locations. There were, however, significant differences among Everglades and Caribbean locations with respect to species TP optima and indicator species. This suggests that although diatoms are effective indicators of water quality in these wetlands, differences in species response to water quality changes can reduce the predictive power of these indices when applied across systems.

Sur le bassin Méditerranéen, l'utilisation des ressources en eau est en constante augmentation depuis plus de cinquante ans. Avec les trois quart des ressources en eau d'origine superficielle, l'exploitation des eaux souterraines apparaît comme une des solutions à la raréfaction de l'eau. Les aquifères karstiques semblent répondre à cette démarche car ils possèdent une réserve en eau importante et facilement renouvelable. L'hydrosystème Cesse-Pouzols, situé dans le Sud de la France, regroupe le bassin versant karstique de la Cesse (275 km²) et l'aquifère karstique de Pouzols. A la limite entre les Corbières au Sud, la Montagne Noire au Nord et le chaînon de St-Chinian à l'Est, sa géologie et sa géométrie sont complexes car héritées des grands évènements tectoniques du Languedoc Roussillon. Durant le quaternaire, l'enfoncement et les changements de cours de la Cesse, ont permis au réseau karstique de se développer, laissant apparaître des zones de pertes et résurgences. La synthèse de l'évolution hydro-géomorphologique du bassin a permis d'établir un premier schéma de fonctionnement hydrogéologique. La description des réseaux de mesures présents et nouvellement installés a permis de regrouper l'ensemble des données pluviométriques, débitmétriques et piézométriques disponibles sur cet hydrosystème permettant l'amélioration des connaissances du site par une analyse hydrodynamique et hydrochimique. Ces analyses ont permis d'identifier les interactions entre eau de surface et eau souterraine, la présence d'une réserve en eau importante au travers d'une bonne conductivité hydraulique ainsi qu'une forte capacité de stockage, une zone de recharge située à l'altitude moyenne du contact entre les terrains calcaires Tertiaires et les terrains Primaires de la Montagne Noire ainsi qu'un mélange entre des eaux très anciennes et des eaux récentes a également été mise en évidence notamment grâce à l'utilisation des isotopes stables de l'eau et les gaz anthropiques (CFCs et SF6). Afin d'estimer un volume maximum prélevable et de proposer une gestion active de l'hydrosystème Cesse-Pouzols, une modélisation conceptuelle globale journalière basées sur le GR4J a été développée. Puis, il a été choisi de développer ce modèle par intégration des interactions surface/souterrain et par la prise en compte des écoulements lents et rapides. Le GR5J ainsi développé, montre des résultats significativement supérieurs au GR4J. La prise en compte des interactions entre les réservoirs de l'aquifère a permis d'élaborer un GR7J. Toutefois, le GR7J ne présente pas d'amélioration nette par rapport au GR5J et fait état d'une « sur-paramétrisation » face aux données disponible aujourd'hui. Le GR5J a donc été utilisé dans la détermination du volume maximum prélevable d'eau souterraine. Malgré les limites de modélisation, le GR5J a été appliqué afin d'illustrer la méthodologie proposée. Le volume prélevable pour l'aquifère de Pouzols est estimé entre 4,5 et 6 millions de m3 par an. Toutefois ce chiffre doit être modulé en fonction de l'établissement du futur débit biologique de la Cesse et de la valeur des prélèvements de surface présents dans le cours pérennes de la rivière. / During the past fifty years, water use has been on a constant increase over the Mediterranean basin, Three quarters of water withdrawals come from superficial water resources. Thus, groundwater resources appears as a solution to surface water rarefaction. karstic groundwater constitutes an important and easily renewable reserve. The Cesse-Pouzols hydrosystem, located in the South of France, is composed by the karstic basin of the Cesse (275 km ²) and the karstic aquifer of Pouzols. At the borderline between the Corbières in the South, the Montagne Noire in the North and the thrust of St-Chinian in the East, its geology and geometry are complex and it inherits from big tectonic events of Languedoc Roussillon. During the quaternary era, karstic network developed owing to changes the Cesse changements of direction , generating zones of losses and resurgences. The synthesis of the basin hydro-geomorphologic evolution allowed establishing a first scheme of its hydrogeological functioning. The description of current networks and newly installed tools allowed collectingrainfall , flow and water table data available on this hydrosystem thusimproving knowledge of the site by a hydrodynamic and hydrochemical analysis. Thanks to these analyses (i) correlations between surface and groundwater were identified as well as(ii) the presence of an important groundwater reserve through a good hydraulic conductivity, (iii) a strong stocking capacity, (iv) a zone of reload located on the medium altitude of contact between the tertiary carbonate formation and the Primary formation of the Montagne Noire. A mixture between very ancient waters and recent waters was also highlighted notably thanks to the use of stable isotopes of water and anthropogenic gases (CFCS and SF6). In order to estimate the maximum volume of groundwater that could possibly be pumped and to offer an active management of the hydrosystem Cesse-Pouzols, a daily conceptual modelling was developed, based on the hydrological model GR4J. It was chosen to develop this model by integration of surface water/groundwater interacations and by the recognition of slow and quick flows. A GR5J model was so developed. The recognition of correlations between the reservoirs of the aquifer allowed setting up a GR7J model. However, GR7J does not introduce net improvement in comparison to GR5J and mentions one «over - parameterization» according to today's available data. The GR5J model was therefore used Maximum volume of groundwater pumped in Pouzols aquifer is estimated between 4,5 and 6 millions of m3 per year. However, this figure must be modulated according to the future environmental flow of the Cesse and to the value of the present samples of the river.

Technique émergente de gestion intégrée des ressources en eau pour résoudre des problèmes de gestion en zones arides, la Recharge Artificielle de Nappe RAN n'est pas appliquée aux aquifères carbonatés à cause des problèmes de karst. Son application au karst devrait cependant s'imposer. Cette thèse a analysé les conditions de recharge naturelle et artificielle, pour proposer une méthodologie d'Analyse de la faisabilité de Recharge Artificielle des aquifères Karstiques (ARAK) afin de définir des sites favorables à une recharge artificielle depuis la surface. 4 critères indépendants (Epikarst, Roche, Infiltration et Karst) sont considérés, indexés dans chaque maille à partir des données géologiques et topographiques, cartographiés selon une méthode d'indexation multicritère. L'indice de rechargeabilité intrinsèque, combinant ces critères, décrit l'aptitude de l'aquifère à être rechargé depuis sa surface, à l'échelle du système, puis à celle des sites les plus favorables. Un facteur de faisabilité technico-économique, mesurant les difficultés techniques et économiques d'une opération de recharge, est ensuite calculé à chaque site. Développée pour prendre en compte les aspects théoriques et pratiques rencontrés en identifiant les sites de RAN à partir de la surface, cette méthodologie devrait servir d'outil de gestion durable des ressources en eau karstique. La méthode ARAK a été testée sur l'aquifère karstique littoral de Damour, Liban, capté pour l'e au potable de Beyrouth, dont l'exploitation non contrôlée a conduit à une intrusion marine. Plusieurs sites de recharge à partir de la surface ont été identifiés. Mais le facteur technico-économique a révélé des difficultés techniques. La solution proposée consiste en une galerie horizontale, pour injecter l'eau de la rivière. Les établissements de l'eau considèrent qu'un tel projet offrira une solution intéressante pour satisfaire la demande en eau et combattre l'intrusion d'eau salée. / Managed Aquifer Recharge MAR is an emerging sustainable technique used to solve water management problems. MAR presents great interest for karst aquifers, however known to present a high heterogeneity. MAR remains till date marginal in karst aquifers. Accordingly, the present work presents a methodology for Aquifer Rechargeability Assessment in Karst ARAK. The aim of ARAK is to determine the ability of a karst aquifer to be artificially recharged from its surface; and the best sites for implementing the recharge. Based on multi-criteria indexation analysis, ARAK considers 4 criteria: Epikarst, Rock, Infiltration, Karst. The criteria are indexed at each mesh of the 2 D grid domain, from geological and topographic data. ARAK computes the intrinsic rechargeability index, describing the rechargeability of a karst aquifer, on the regional scale, then on the identification of rechargeable sites. Subsequently, a feasibility factor, weighting the techn ical and economic difficulties of a recharge operation, is applied to the selected sites. The methodology, developed to reconcile the problems encountered to identify sites for MAR in karst, provides a useful tool to help water authorities to determine the potential of MAR in karst aquifers. ARAK was applied to Damour site (Lebanon). This coastal aquifer, source of water supply for Beirut, was salinated by its uncontrolled exploitation. A MAR system in Damour region should remediate to it. The four ARAK criteria were indexed and mapped. The final map showed that the aquifer is favorable to a recharge operation, and identified several potential rechargeable sites. However, the feasibility factor indicated that major difficulties hinder the use of infiltration ponds. The solution proposed consists of drilling a horizontal gallery for injecting river water. Water authorities consider that an aquifer recharge project could offer solutions for the shortage in water supply and the sea water intrusion.

A ordem Pseudoscorpiones possui 3.800 espécies ao redor do globo e contribuem com grande parte da diversidade dentre os Arachnida. Apresentam tamanho reduzido, hábitos criptobióticos e podem ocorrer em diversos hábitats, inclusive em cavernas, as quais ocorrem nas mais diferentes litologias, como calcário, arenito, quartzito, gnaisse, minério de ferro, entre outras. Essas litologias encontram-se espalhadas pelo território nacional nas mais diversas áreas cársticas. Nas cavernas, os pseudoescorpiões são encontrados em diferentes tipos de substratos, os quais podem ser orgânicos (guano, folhiço, troncos) ou inorgânicos (rocha, substrato inconsolidado). No Brasil há 167 espécies descritas em 14 famílias, das quais nove podem ser encontradas no meio hipógeo, com 28 espécies. Desta maneira, levantamos as seguintes questões: 1. Há influência da litologia na distribuição deste táxon no Brasil? 2. Há preferência destes por substratos específicos no habitat hipógeo? 3. Há famílias que são restritas a áreas específicas do país? Para responder essas questões, realizamos um levantamento da fauna pseudoescorpiônica nas cavernas brasileiras e mapeamos a distribuição destes, utilizando dados presentes na literatura e novos levantamentos realizados em diferentes áreas do país. Categorizamos os substratos, as áreas cársticas e as litologias e realizamos análises de correspondência, seguidas de testes de significância. Confeccionamos mapas de distribuição das famílias encontradas nas cavernas, ampliamos o número de famílias que podem ser encontradas em cavernas no país, a distribuição de espécies já conhecidas e registramos espécies novas. Registramos 61 morfotipos em 13 famílias, elevando o número de famílias presente em cavernas brasileiras. Dentre estas, registramos o primeiro pseudoescorpião da família Pseudochiridiidae para o continente sul americano e as famílias Atemnidae, Cheliferidae e Geogarypidae foram registradas pela primeira vez em cavernas do Brasil. Alteramos o status ecológico evolutivo das espécies do gênero Spelaeochernes e da espécie Spelaeobochica allodentatus para a troglóbios. Quanto às questões levantadas, verificamos que a litologia, assim como as diferentes áreas cársticas influenciam na distribuição desta fauna, e que há famílias que ocorrem em áreas específicas do país e não há preferência por substratos específicos dos pseudoescorpiões nas cavernas. Verificamos a importância e singularidade desta fauna para o ambiente cavernícola e concluímos que a consideração desta é fundamental para subsidiar tomadores de decisões no âmbito da conservação no Brasil. / The order Pseudoscorpiones has 3,800 species around the world and contributes for a great part of the diversity among the Arachnida. They present small size, cryptobiotic habits and can occur in many habitats, including caves, which occur in many different lithologies such as limestone, sandstone, quartzite, gneiss, and iron ore, among others. These lithologies are spread throughout the country in many karst areas. In the caves, the pseudoscorpions are found in different types of substrates, which may be organic (guano, leaf litter, logs) or inorganic (rock, unconsolidated substrate). In Brazil, there are 167 described species in 14 families, nine of which can be found in caves, with 28 species. Thus, we raise the following questions: 1. is there influence of lithology on the distribution of this taxon in Brazil? 2. Is there preference for specific substrates in hypogean habitat? 3. Are there families that are restricted to specific areas of the country? To answer these questions, we conducted a survey of pseudoscorpion fauna in Brazilian caves and mapped the distribution of these, using data from the literature and new samples in different areas of the country. We categorized the substrates, the karst areas and lithologies and perform correspondence analysis, followed by tests of significance. We made maps of distribution of families found in the caves, we expanded the number of families that can be found in caves in the country, increased the distribution of species already known and recorded new species. We recorded 61 morphotypes in 13 families, increasing the number of families present in Brazilian caves. Among these, we also recorded the first pseudoscorpion of Pseudochiridiidae family to South American continent, and the families Atemnidae, Cheliferidae and Geogarypidae were registered for the first time in the caves of Brazil. We changed the eco-evolutionary status of the genus Spelaeochernes and the specie Spelaeobochica allodentatus for troglobitic. Related to the questions raised, we found that the lithology as well as the different karst areas influence on the distribution of this fauna and that there are families that occur on specific areas of the country and there is no preference for specific substrates of pseudoscorpions in caves. We verified the importance and singularity of this fauna to the cave environment and concluded that it is essential to consider it to support decisions makers in the conservation context in Brazil

Saltwater intrusion alters the natural salinity and phosphorus (P) gradients in the oligotrophic, freshwater wetlands located near coastlines of the Caribbean Basin with important consequences to the structure and function of key ecosystem components, including plants, soil microbes, and periphyton. Periphyton communities, particularly diatoms, are extremely sensitive to water quality changes and can serve as excellent bioindicators; however, little is known about their use in detecting novel rates of saltwater intrusion into coastal, freshwater wetlands. I examined the individual and combined effects of elevated salinity and P on periphyton functional processes and diatom composition by conducting transect surveys along salinity and P gradients in the southern Everglades, as well as through mesocosm studies in which salinity and P were experimental manipulated. I demonstrated that conductivity (a proxy for salinity) and P gradients drive spatial patterns in diatom assemblage structure in the southern Everglades and that these assemblages have relatively low conductivity (2 mS cm-1) and total P thresholds (82 µg g-1). These findings were supported by the experimental work which showed that monthly pulses of elevated salinity only ~1 ppt above ambient was sufficient to cause significant shifts in periphytic diatom assemblages along with reduced periphyton productivity, total carbon, and nutrient content. The addition of P to freshwater and salt-treated periphyton significantly elevated mat total P, underscoring the P-uptake efficiency of periphyton. Surprisingly, addition of P to freshwater periphyton did not elicit significant functional or compositional responses, although chlorophyll-aconcentrations and accumulation rates tended to be higher with P. Similar chlorophyll-atrends were observed for salt-treated mats with added P, but these mats also exhibited significantly higher gross primary productivity and net ecosystem productivity compared to all other treatments and a diatom assemblage distinct from any other treatment. This research provides new and valuable information regarding periphyton dynamics in response to changing water sources that will allow us to extend the use of periphyton, and their diatom assemblages, as tools for environmental assessments related to saltwater intrusion in the southern Everglades and other karstic, freshwater wetlands.

A ordem Pseudoscorpiones possui 3.800 espécies ao redor do globo e contribuem com grande parte da diversidade dentre os Arachnida. Apresentam tamanho reduzido, hábitos criptobióticos e podem ocorrer em diversos hábitats, inclusive em cavernas, as quais ocorrem nas mais diferentes litologias, como calcário, arenito, quartzito, gnaisse, minério de ferro, entre outras. Essas litologias encontram-se espalhadas pelo território nacional nas mais diversas áreas cársticas. Nas cavernas, os pseudoescorpiões são encontrados em diferentes tipos de substratos, os quais podem ser orgânicos (guano, folhiço, troncos) ou inorgânicos (rocha, substrato inconsolidado). No Brasil há 167 espécies descritas em 14 famílias, das quais nove podem ser encontradas no meio hipógeo, com 28 espécies. Desta maneira, levantamos as seguintes questões: 1. Há influência da litologia na distribuição deste táxon no Brasil? 2. Há preferência destes por substratos específicos no habitat hipógeo? 3. Há famílias que são restritas a áreas específicas do país? Para responder essas questões, realizamos um levantamento da fauna pseudoescorpiônica nas cavernas brasileiras e mapeamos a distribuição destes, utilizando dados presentes na literatura e novos levantamentos realizados em diferentes áreas do país. Categorizamos os substratos, as áreas cársticas e as litologias e realizamos análises de correspondência, seguidas de testes de significância. Confeccionamos mapas de distribuição das famílias encontradas nas cavernas, ampliamos o número de famílias que podem ser encontradas em cavernas no país, a distribuição de espécies já conhecidas e registramos espécies novas. Registramos 61 morfotipos em 13 famílias, elevando o número de famílias presente em cavernas brasileiras. Dentre estas, registramos o primeiro pseudoescorpião da família Pseudochiridiidae para o continente sul americano e as famílias Atemnidae, Cheliferidae e Geogarypidae foram registradas pela primeira vez em cavernas do Brasil. Alteramos o status ecológico evolutivo das espécies do gênero Spelaeochernes e da espécie Spelaeobochica allodentatus para a troglóbios. Quanto às questões levantadas, verificamos que a litologia, assim como as diferentes áreas cársticas influenciam na distribuição desta fauna, e que há famílias que ocorrem em áreas específicas do país e não há preferência por substratos específicos dos pseudoescorpiões nas cavernas. Verificamos a importância e singularidade desta fauna para o ambiente cavernícola e concluímos que a consideração desta é fundamental para subsidiar tomadores de decisões no âmbito da conservação no Brasil. / The order Pseudoscorpiones has 3,800 species around the world and contributes for a great part of the diversity among the Arachnida. They present small size, cryptobiotic habits and can occur in many habitats, including caves, which occur in many different lithologies such as limestone, sandstone, quartzite, gneiss, and iron ore, among others. These lithologies are spread throughout the country in many karst areas. In the caves, the pseudoscorpions are found in different types of substrates, which may be organic (guano, leaf litter, logs) or inorganic (rock, unconsolidated substrate). In Brazil, there are 167 described species in 14 families, nine of which can be found in caves, with 28 species. Thus, we raise the following questions: 1. is there influence of lithology on the distribution of this taxon in Brazil? 2. Is there preference for specific substrates in hypogean habitat? 3. Are there families that are restricted to specific areas of the country? To answer these questions, we conducted a survey of pseudoscorpion fauna in Brazilian caves and mapped the distribution of these, using data from the literature and new samples in different areas of the country. We categorized the substrates, the karst areas and lithologies and perform correspondence analysis, followed by tests of significance. We made maps of distribution of families found in the caves, we expanded the number of families that can be found in caves in the country, increased the distribution of species already known and recorded new species. We recorded 61 morphotypes in 13 families, increasing the number of families present in Brazilian caves. Among these, we also recorded the first pseudoscorpion of Pseudochiridiidae family to South American continent, and the families Atemnidae, Cheliferidae and Geogarypidae were registered for the first time in the caves of Brazil. We changed the eco-evolutionary status of the genus Spelaeochernes and the specie Spelaeobochica allodentatus for troglobitic. Related to the questions raised, we found that the lithology as well as the different karst areas influence on the distribution of this fauna and that there are families that occur on specific areas of the country and there is no preference for specific substrates of pseudoscorpions in caves. We verified the importance and singularity of this fauna to the cave environment and concluded that it is essential to consider it to support decisions makers in the conservation context in Brazil

Dans le but de caractériser les conditions environnementales, hydrologiques et d’usage des sols, menant à la contamination d’un système karstique cette étude combine hydrogéologie et microbiologie environnementale. Les chroniques de température et d’hydrologie (pluviométrie, turbidité, conductivité) de l’hydrosystème karstique de Norville (SO Karst) des 5 dernières années ont été analysées pour trouver une corrélation entre les conditions hydrologiques menant au ruissellement sur le bassin versant et la contamination par E. coli de l’hydrosystème (eau et biofilms). Quinze campagnes de prélèvement d’eau à l’entrée (la perte) et la sortie (la source) du système et de biofilms ont été réalisées. La relation entre l’abondance et la diversité génétique (distribution des phylogroupes) des populations de E. coli circulant dans l’hydrosystème et les conditions hydrologiques et d’usage des sols a été étudiée. Un indicateur de contamination des eaux par E. coli (IndiCE) basé sur l’enregistrement de la température et la pluviométrie et corrélé avec la contamination d’eau de surface et sous terraine par E. coli d’un hydrosystème karstique, simple d’utilisation est proposé. Le rôle de réservoir de pathogène des biofilms karstiques, responsable de contamination secondaire, a été étudié en suivant l’occurrence de E. coli et des intégrons de classe 1 dans des biofilms formés à la source de l’hydrosystème karstique de Norville.Il a été montré en chemostat la capacité de E. coli à former des biofilms sur la craie en condition oligotrophique. In situ E. coli et les integrons de classe 1 peuvent s’associer à des biofilms autochtones sous forme cultivable transitoirement. L’ensemble de ces travaux de thèse a permis de mieux comprendre la dynamique de la contamination par E. coli des hydrosystèmes karstiques, dans l’eau et les biofilms. / In order to assess environmental conditions leading to contamination of a rural karstic hydrosystem this study combine hydrogeology, and environmental microbiology. We focused on a well-characterized chalk karstic hydrosystem (Norville, France) vulnerable to microbiological pollution, of the French national observatory network on karst (INSU/CNRS). Temperature and hydrological time series (pluviometry, turbidity and electrical conductivity) over the past 5 years were analysed in order to correlate hydrological condition leading to run-off on the watershed and E. coli contamination of the hydrosystem. Fifteen sampling campaigns of water and biofilms were carried out in different hydrological conditions, on the surficial watershed (i.e. the upstream part of the system) and at the spring downstream. That has been used to determine periods more subject to soil bacteria leaching and input in the hydrosystem. Finally, relationships between abundance and genetic diversity (phylogroup distribution) of E. coli population in the hydrosystem waters, hydrological conditions and land use were investigated. An hydrological indicator (IndiCE) based on the analysis of pluviometry, conductivity, turbidity and temperature time series has been constructed to assess the vulnerability of such karstic hydrosystem to E. coli contamination according to hydrological conditions. The role of karstic biofilm as pathogens reservoir and class 1 integrons, responsible of secondary contamination, has been studied recording E.coli occurrence in karstic biofilms sampled at Norville’s spring. It has been showed in reactor E. coli capacity to form biofilms on chalk in oligotrophic conditions. In situ cultivable E. coli and class 1 integrons can integrate autochthonous biofilms transiently. E. coli population structure in biofilms is significantly the same than in spring water. This thesis work allowed to a better understanding of E. coli contamination dynamic in water and biofilm of karstic hydrosystem.

Groundwater can be a critical issue to be considered in civil engineering, mining engineering and interdisciplinary fields. Karstic structures and aquifers enclosing groundwater are potential risks in case they are not studied in detail. Enclosed groundwater can result in floods at pit bottom or can cause instabilities of permanent pit slopes. This study is about analyses of flooding possibility at the pit bottom and possible instabilities of pit slopes in the Elbistan-&Ccedil / &ouml / llolar open cast coal mine due to the presence of a karstic aquifer under the lignite formation. Thickness and permeability of the bottom clay formation under the lignite bed are necessary critical parameters for investigating a possible water rush from a confined aquifer in limestone formation underneath the bottom clay. These parameters were changed, and water flow quantities towards the pit bottom were determined by finite element models. Critical values of these parameters were investigated considering the lack of accurate site investigation information regarding the thickness and permeability of bottom clay. Possible strength loss, fracturing, and thus permeability increase in bottom clay due to a confined aquifer were studied. In flooding and slope stability analyses Phase2 software based on finite element method is used. Results of analyses showed that as reported thickness of bottom clay is around 120 m at the pit bottom and permeability values are in orders of magnitudes of 10-8 m/s, no serious flooding problems are expected to occur unless the thickness of bottom clay layer drops down to around 20 m, and the permeability of this layer reaches an order of magnitude of 10-5 m/s. Mechanical effects of confined aquifer on slopes and bottom clay displacements were investigated, and thus fracturing and failure possibilities of bottom clay and permanent slope were assessed. Slope and pit bottom displacements increased to meter levels for less than 60 m bottom clay thicknesses. Whereas 50-60 m bottom clay thickness can be critical for cracking, 20 m bottom clay thickness was found to be critical for water rush to the pit bottom. With reported bottom clay thickness of 120 m and with 25o slope angle permanent slope factor of safety was found to be 1.2, and this value was not effected unless clay layer thickness drops below 70 m levels. Higher than 32o overall slope angle there will be a risk of slope failure for permanent and production slopes, reflected by safety factors less than one, in the stability analyses.

7 Abstract Groundwater flow and highly permeable zones in aquifers of eastern part of Bohemian Cretaceous Basin based on Litá area and surroundings In my thesis I deal with the character of highy permeable zones in marlstones and calcitic sandstones in east-bohemian synclines of the Czech Cretaceous Basin. My chosen area lies southwest of Nové M�sto nad Metují and within it lies Litá area, an important source of groundwater for Hradec Králové region. Groundwater in the area was contaminated in the 80's by chlorinated hydrocarbons. Based on a detailed field sampling of 23 boreholes and 4 sites of surface water performed in 2008 and on archival data on contaminant concentrations, I evaluate the character and relationships of groundwater from the boreholes. I grouped boreholes according to their chemical properties. In the second part of my thesis, I perform the analysis of the influence of faults on groundwater flow in a larger area of east-bohemian synclines. Results show that most yielding boreholes lie between fractures, not near them, which suggests the impermeable role of fractures. From available information I then try to answer the question of highly permeable zones of preferential groundwater flow. Based on the observed flow velocity,...

Il est communément admis que la recharge des aquifères carbonatés est contrôlée par la zone non saturée, siège d’une mise à l’équilibre des phases liquides, solides et gazeuses. L’épikarst, zone superficielle de ces aquifères, recueille les pluies efficaces et les transfère en profondeur via une double porosité de fissure et de fracture. Des épandages détritiques sablo-argileux fossilisent souvent les paléo-reliefs, changeant ainsi les caractéristiques des zones d’infiltration. Toutefois, les données sur ces dépôts superficiels sont rares, et leur impact sur les modalités de recharge en contexte karstique est aujourd’hui mal connu et peu décrit.La célèbre grotte préhistorique ornée de Lascaux offre une fenêtre d’observation à l’intérieur de l’épikarst et constitue ainsi un site privilégié pour le suivi des processus de transferts. La grotte fait partie d’un réseau karstique fossile partiellement comblé par du matériel détritique sablo-argileux. Les parties basses de la cavité montrent des fortes teneurs en CO2 dans l’air, supérieures à 8% (80 000 ppmv) lors de certaines périodes estivales. Cette thèse propose une étude des caractéristiques de l’infiltration en milieu karstique grâce au suivi des variations chimiques et isotopiques d’une émergence épikarstique au plafond de l’entrée de la grotte. Les principaux objectifs sont la compréhension de la dynamique des fluides en transit dans l’épikarst, la recherche de la source des fortes teneurs en CO2 ainsi que la détermination du rôle des épandages détritiques dans les modalités de recharge de l’aquifère karstique.Après avoir mener une étude approfondie de l’environnement géologique et géomorphologique du site, l’analyse hydroclimatique, combinée au suivi bimensuel de la chimie et des variations isotopiques des eaux épikarstiques, a permis d’investiguer le fonctionnement de la zone d’infiltration du karst d’un point de vue des transferts de masse.Les premières observations montrent que l’émergence épikarstique n’est pas pérenne avec un tarissement qui débute au début de l’été. Le système nécessite environ 250 mm de recharge automnale pour se réactiver. Le signal 18O à l’émergence est fortement amorti comparé au signal 18O dans les pluies ce qui démontre la création d’une réserve épikarstique qui conduit à l’homogénéisation chimique des eaux. Ainsi, les transferts de masse sont lents dans ce système caractérisé par un comportement de type fissuré et non karstique. Les données de 13C collectées à l’émergence permettent de retracer les conditions physico-chimiques qu’ont rencontrées les eaux au cours de leur transit. Elles montrent différentes origines possible de l’infiltration et révèlent des phénomènes de dégazage – précipitation lors des périodes de fortes pluies.De plus, les eaux épikarstiques sont fortement sursaturées vis-à-vis de la calcite et leur forte minéralisation résulte de la mise à l’équilibre avec une pCO2 importante (5% en moyenne). De telles valeurs ne correspondent pas à la production de CO2 du sol. L’autre origine supposée est les épandages détritiques sablo-argileux où des teneurs importantes en CO2 ont été mesurées (pCO2air de 4 à 8%). De plus, la présence d’eau dans ces niveaux suggère que le système est en partie alimenté par ces formations. Ainsi, le transit des eaux au travers de milieux aux conditions physico-chimiques très contrastés pourrait être à l’origine de la sursaturation des eaux qui entrent dans la cavité.Enfin, l’étude montre que les épandages détritiques tiennent deux rôles majeurs dans les processus d’infiltration des eaux : (i) ils participent à leur homogénéisation en les stockant proche du sol et (ii) ils fournissent un fort potentiel de karstification au système. / It is widely recognized that the recharge of deep carbonated aquifers is controlled by a non saturated zone in which liquids, solids and gases are exchanged to attain equilibrium. The epikarstic zone, which represents the bottom of these aquifers, collects the efficient rain waters and transfers them deeper through a dual fractured and fissured porosity. Sandy-clayey detritic coatings are often observed to fossilize the paleo-relief changing the features of the infiltration zones. However, field data on these superficial deposits are sparse and their impact on the recharge modalities in karstic context is not yet well known and described.The famous prehistoric painted cave of Lascaux (France) provides a window into the epikarstic system and offers a privileged environment for the monitoring of transfer processes. The Lascaux cave is part of a fossil karstic network partly filled with detritic material and it is known to have high CO2 concentrations, greater than 8% (80,000 ppmv) in some summer periods, when measured in the air of the lower parts of the cave. Here, we study the epikarstic seepage traits monitoring the chemical and isotopic variations in waters which seep from the entrance roof of the cave. The aims of this work are to understand the dynamics of the fluids in the epikarstic system, to find the source of the high CO2 concentrations measured into the cave and to understand how the detritic coatings impact on the recharge modalities. After carried out an in-depth geological and geomorphological study of the site, the use of hydroclimatic analysis combined with the semi-monthly hydrochemical and isotopic monitoring of the epikarstic waters allowed us to investigate the karstic infiltration zone functioning in term of matter transfer. First, we observed that the epikarstic emergence is non perennial and dries up at the beginning of summer. The system needs an approximately 250 mm recharge in autumn before seeing flows at the emergence. The 18O signal at the emergence is highly amortized compared to the rain 18O signal which reveals the creation of an epikarstic water table that chemically homogenises waters. Thus, the mass transfers are slow in this system characterized by a fissured and nonkarstic behaviour type. The 13C data obtained at the epikarstic emergence seem to characterize the physicochemical conditions of the environments in which waters circulate during their transit in the system. They confirm the possible various origins of waters and reveal degassing – precipitation phenomena during rising periods.Moreover, épikarstic waters are always supersaturated with respect to the calcite and the the high bicarbonates and calcium concentrations result from water equilibrate with an important pCO2 at saturated state (5% on average). Such values of pCO2 do not correspond to the soil CO2 production. The other supposed origin is the sandy clayey detritic formations where we measured important pCO2 (data range from 4 to 8% in the atmosphere of the coatings). Furthermore, the presence of water in the sandy levels of the coatings suggests that the system can be partly fed by these formations. The transit of water through two physicochemicaly highly contrasted environments would be at the origin of the general flows supersaturation state in the cave.Finally, the study shows that the detritic coatings are involved in two aspects of the epikarstic waters run-off conditions: (i) they homogenize them while retaining near to the soil and (ii) give to them a very high karstification potential.