La resuspension de sédiments contaminés peut entraîner le relargage d'éléments traces métalliques (ETM) dans la phase dissoute. Pour anticiper le risque de remobilisation des ETM lors de la vidange des retenues de barrages et créer un modèle géochimique permettant de prédire ce risque, des expériences de resuspension de sédiments provenant de trois retenues ont été réalisées pendant une semaine dans un réacteur. Le pH et le potentiel redox ont été suivis en continu et des échantillons ont été prélevés afin de mesurer l'évolution des ETM dissous. Trois grandes tendances d'évolution des ETM ont été mises en évidence et ne sont pas modifiées par les variations des masses de sédiment en suspension (entre 2 et 9 g/L): 1) Cr, Cd et Zn ne sont pas relargués. 2) Mn, Fe Co, Pb, ainsi que As pour deux retenues, augmentent puis diminuent au cours du temps. Ces éléments sont contrôlés par les oxyhydroxydes de Fe et de Mn et l'évolution du potentiel redox dans la solution. 3) Mo, Al, ou As pour une retenue, continuent d'augmenter à la fin des expériences, révélant des processus de relargage plus lents et une stabilisation dans la phase dissoute. Dans les trois retenues, As est l'élément le plus fortement et durablement relargué. Ces données expérimentales ont été utilisées pour calibrer un nouveau modèle géochimique développé par EDF sur ECOLEGO, intégrant la cinétique des réactions d'échange des ETM entre la phase dissoute et trois types de phases solides: les oxydes, les particules organiques et les carbonates. La calibration des paramètres cinétiques permet de bien reproduire les évolutions temporelles des concentrations qui augmentent (relargage) puis diminuent (piégeage). / The resuspension of the contaminated sediments may promote the remobilization of trace metals to the dissolved phase, threatening the water quality. The dam reservoirs sometimes need to be fully drawn down and being able to anticipate the release of the contaminants is essential to improve the management of reservoirs and assess the risk of water quality degradation. Surface sediments were collected in three contaminated dam reservoirs and aliquots of wet sediments were resuspended for a week in a reactor. The pH and the redox potential were continuously measured, dissolved samples were collected and the evolution of dissolved trace elements concentrations were measured. Depending on the elements, different temporal trends can be highlighted during the resuspension experiments. These evolutions were reproducible, regardless of the mass of sediment used from 2 to 9 g/L. 1) Cd, Cr and Zn were not released; 2) Mn, Fe, Co, Pb and As for two reservoirs, increased and then decreased during the experiments and were regulated by the Fe- and Mn-oxyhydroxides and the redox potential; 3) Al, Mo, or As for one reservoir, were still increasing at the end of the experiments, showing slower release processes and the stabilization of these elements under dissolved forms. For theses three reservoirs, As showed the greatest and the most prolonged release during resuspension. The experimental trends of dissolved metals were used in the firts calibration steps of a new chemical speciation model developped by EDF, which takes several kinetic rates into account for the exchange reactions of dissolved metal between water and three types of solid phases.

This dissertation aims to improve our understanding of how dams and reservoirs impact freshwater systems worldwide. The following questions were addressed specifically: 1) what are the spatial patterns and magnitudes of flow regulation and channel fragmentation by dams globally; 2) how are dam impacts distributed biogeographically, and which are the biogeographic regions and taxa most threatened by dam impacts; and 3) how can climate change and dams be expected to interact in basins, and what management actions would mitigate adverse interactions? Results show that the majority of the world’s large river systems are fragmented and have their flow altered by dams. Exceptions to this tend to lie in regions inhospitable to hydropower development, such as northern tundra, or in the least economically active regions. The biogeographic distribution of dam impact is widespread, both at terrestrial and freshwater scales, representing significant threat to global biodiversity. Relatively species-poor tundra is the world’s only terrestrial ecoregion which remains predominantly unaffected by dams. Nearly half of the world’s freshwater ecoregions are internally fragmented by dams, and ecoregional distinctions may be artifically imposed by dams in many cases. Freshwater ecoregions with the highest counts of total and endemic species remain relatively unobstructed, representing significant conservation potential. Diadromy is one of the few fish traits indicative of vulnerability to dams for which data are sufficient for global scale analysis. Lampreys (Lampetra spp.), Eels (Anguilla spp.) and Shad (Alosa spp.) are examples of genera particularly vulnerable to dams because their distributions coincide with the most heavily fragmented freshwater ecoregions, and a large proportion of the coincident species for each genera are diadromous. Due to changes in discharge and water stress, the area of large river basins in need of management interventions to protect ecosystems or people will be much greater for basins impacted by dams than for basins with free-flowing rivers. Proactive measures that restore the natural capacity of rivers to buffer climate-change impacts are more desirable than reactive actions since they may also lead to environmental benefits such as higher water quality and restored fish populations – benefits which may later be unattainable.

La charge interne en phosphore (P) sédimentaire stockée dans les retenues de barrages retarde la restauration du processus d’eutrophisation. Ainsi, l’étude de la mobilité du P sédimentaire dans les retenues de barrage permet d’une part de comprendre son cycle géochimique dans ces systèmes, d’autre part de mieux appréhender les politiques de gestions de restauration des milieux. Cette étude met en évidence l’impact de trois barrages en cascade (Complexe de l’Age, Creuse, France) sur la distribution du P sédimentaire le long d’un continuum fluviatile. Dans les retenues étudiées, les teneurs en TP sont en moyenne de 1,59 ± 0,51 mgP/gsec et augmentent en direction des barrages. Ceci contraste avec les faibles teneurs observées dans les parties fluviatiles. Dans les réservoirs, le fractionnement chimique a montré que plus de 50% du P extrait était associé à la fraction ascorbate. L’association du P avec les oxy-hydroxydes de Fe amorphes dans les particules fines des sédiments accumulées près du barrage, s’avère être le facteur majeur expliquant les variations longitudinales des teneurs en TP. De plus, ces fortes teneurs associées à ces phases redox-sensibles et la mise en évidence d’un hypolimnion anoxique, révèle le fort potentiel de mobilisation de P sédimentaire dans ces retenues. En condition aérobie, un risque de mobilisation résultant d’un équilibre des concentrations en P entre soluté et fraction solide existe néanmoins. La détermination de valeur seuil EPC0 a souligné l’évolution du rôle de puits/source du sédiment vis-à-vis du P entre les retenues d’un même complexe. Enfin, l’étude de la mobilité du P sédimentaire en laboratoire, suite à deux cycles successifs aérobies et anaérobies montre que l’oscillation du potentiel d’oxydo-réduction, observé dans les retenues, favorise la mobilisation du P sédimentaire. La géochimie du Fe et la qualité de la matière organique dissoute semble être tous les deux impliqués dans la mobilité du P. / Internal sedimentary phosphorus (P) load cause delay time in eutrophication recovery, especially in dam-reservoir systems where P stock are important. Then, the study of sedimentary P mobility in dam-reservoirs allow to better explain P geochemistry in this context and further to adapt management restauration policies. This study highlights the impact of three cascade dams (Age Complex, Creuse, France) on the distribution of sedimentary P along a fluvial continuum. In the impoundments studied, TP levels averaged 1.59 ± 0.51 mgP /g DW and increased towards dams. This contrast with the low and constant concentrations observed in the fluvial parts. In reservoirs, chemical fractionation showed that more than 50% of the extracted P was associated with the ascorbate fraction. The association of P to amorphous Fe oxi-hydroxides in the fine particles accumulated closed to the dam is the major factor explaining the longitudinal variations of the TP contents. In addition, the high levels of P associated with these redox-sensitive phases and the development of a hypoxic hypolimnion in studied reservoirs reveal the high potential for sediment P mobilization. Moreover, in aerobic conditions, a risk of mobilization resulting from an equilibrium concentration between solute and solid fraction exists. The determination of the EPC0 threshold value underlined the spatial evolution of the sink / source role of the sediment with respect to the P, between the reservoirs of the same complex. Finally, the study of sedimentary P mobility in the laboratory, following two successive aerobic and anaerobic cycles, showed that redox potential oscillation observed in the reservoirs, favors the mobilization of the sedimentary P. The geochemistry of iron and the quality of dissolved organic matter appear to be involved in the mobility of P.

The aim of those study was to find out an up-to date content of mercury in the tissues of fish in the dam reservoir Jordan in Tabor. To compare particular fish according to their species, age and dietary strategy and their capability to accumulate mercury. The distribution and the mutual rates of total content of mercury in particular tissues of carnivorous and non-carnivorous species of fish were determined (muscle, liver, kidneys). Dedicated atomic absorption spectrophotometer AMA 254 was used to determine the total content of mercury. The results show that exceeding the former hygienic limit 0.1 mg.kg-1 w. w. in the muscle of non-carnivorous fish with almost all samples. It was the low-age carnivorous species of fish was probably the cause that the hygienic limit (0,5 mg.kg-1 w. w.) was exceeded only rarely (in the muscle a five-year-old asp, Aspius aspius, 0,888 {$\pm$} 0,041 mg.kg-1 w. w.). The pond Kosin located above the dam reservoir Jordan was exploitation as a comparative locality. The average content of mercury in the muscle of selected indicator species of fish in the reservoir Jordan - bream large (Abramis brama) at the age of 5 years - it was 0,241 {$\pm$} 0,080 mg.kg-1 w. w., whereas from comparative locality, from the pond Kosin, for the same species and age of fish it was only 0,045 {$\pm$} 0,008 mg.kg-1 w.w., i.e. more than five times more of the content in comparison with an unweighted locality. The realized results also show that the burden of the fish with mercury for a common consumer does not exceed neither the {\clqq}hazard index`` (HI) nor the toxicological limit ( the maximum recommended ration a week from the food is 1,6 {$\mu$}g MeHg per 1 kg of body weight according) to the WHO. However, with more intensive consumption of mainly carnivorous fish from the reservoir Jordan, e.g. of the sport fishermen´s family members, it could cause risk from this consumption ( i.e. HI > 1). Further work should be aimed at monitoring of the content of mercury in the tissues of mainly predators of higher age category.

Esta pesquisa objetivou mostrar a viabilidade de utilização do Sistema de Informação Geográfica (SIG) associado à modelagem matemática, como opção metodológica a ser aplicada no estudo das modificações induzidas no nível freático, após o enchimento de reservatórios. A área piloto escolhida foi a bacia de drenagem do rio Biritiba-Mirim, localizada na região do Alto Tietê, no Estado de São Paulo. O entendimento do funcionamento do sistema hidrogeológico, obtido por meio de dados de geologia, hidrogeologia, climatologia, poços existentes e sondagens executadas na área, subsidiou a elaboração do modelo conceitual. Na área, foram identificados dois tipos de aqüíferos: o Sedimentar, restrito às planícies fluviais e o Cristalino alterado, decorrente da alteração intempérica da rocha. Os fluxos locais da água subterrânea ocorrem em direção aos cursos d’água que constituem a malha de drenagem da bacia, enquanto que, regionalmente, as águas subterrâneas fluem na direção do rio Biritiba-Mirim. As informações do modelo conceitual foram, inicialmente, organizadas no Sistema de Informação Geográfica e, posteriormente, transferidas para o modelo matemático. Foi construído um modelo matemático para a bacia de drenagem do rio Biritiba-Mirim utilizando o programa tridimensional de diferenças finitas MODFLOW desenvolvido por McDONALD & HARBAUGH (1988). A calibração do modelo foi executada a partir de ajustes sucessivos, efetuados por meio do SIG e, posteriormente, aferidos no MODFLOW. Uma vez concluído o processo de calibração, procedeu-se à simulação do enchimento do reservatório, utilizando novamente o Sistema de Informação Geográfica para a entrada dos dados. A simulação, também realizada no MODFLOW, possibilitou delimitar as áreas nas quais os níveis das águas subterrâneas sofrerão maiores influências do reservatório, dando o subsidio necessário para a locação dos poços de monitoramento. Os dados coletados no período de um ano de monitoramento permitiram executar a verificação e eventuais correções do modelo. Com o modelo aferido, repetiu-se a simulação do enchimento do reservatório e, a partir do mapa potenciométrico resultante, foi elaborado o mapa de profundidades de níveis d’água subterrânea previstas para após o enchimento do lago, denominado de Mapa Previsional de Influência. Nesse mapa foram delimitadas duas zonas de influência (de 0-5 m e de 5-10 m) e uma zona sem influência do reservatório ou com profundidade final do nível freático superior a 10 m. Finalmente, definiu-se um programa de monitoramento potenciométrico do sistema aqüífero livre para execução em situação posterior ao enchimento do reservatório, a fim de avaliar o tempo e tipo de resposta do aqüífero livre ao processo de enchimento e efetuar a retroanálise das previsões. De acordo com programa definido, a primeira campanha de medição deverá coincidir com o início do enchimento do reservatório, a partir desta, o monitoramento deverá ser mensal até os três primeiros meses e, posteriormente, trimestral até completar um ano após o enchimento. A execução do presente estudo comprovou a viabilidade da aplicação do SIG, associado à modelagem matemática com fins previsionais, em escala de bacia de contribuição, para a avaliação das modificações induzidas no nível do aqüífero livre após o enchimento de reservatórios. Recomenda-se a metodologia aqui proposta como ferramenta a ser aplicada em outros locais que apresentem a mesma problemática. / The purpose of the current research was to demonstrate the viability of using Geographic Information System – GIS associated to mathematical models as a methodological option to be applied in the study of the water table elevation induced by dam reservoirs after their impoundment. The chosen area was the drainage basin of Biritiba-Mirim river, located in Alto Tietê area, in São Paulo State. The understanding of the hydrogeological system was acquired through geological, hydrogeological and climatological data. The surveys executed in the area, also allowed the construction of the conceptual model. In the area, two aquifers types were identified: the Sedimentary, restricted to the fluvial plains, and the altered Crystalline, due to the weathering. The regional groundwater flow was toward Biritiba-Mirim river, while the secondary drainage was a local groundwater discharge area. The conceptual model data was, initially, organized in a Geographic Information System and later transferred to the mathematical model. A mathematical model was built on the Biritiba-Mirim drainage basin using MODFLOW, a three-dimensional program of finite differences developed by McDONALD & HARBAUGH (1988). The model calibration was executed through successive trial-error process, using Geographic Information System as a input data and MODFLOW to evaluate results. After the conclution of the calibration process, the Biritiba-Mirim reservoir impoundment was simulated using Geographic Information System to input the new variable. The simulation, also accomplished in MODFLOW, made possible to limitate the main areas that will be impacted on their ground water levels. Using that map were located the monitoring wels. From the monitoring data, collected in a year period, it was possible to verify the model. The reservoir impoundment simulation was repeated. From the resulted potenciometric map, the groundwater final depths map was elaborated. In that map, named Predictional Influence Map, two influence zones were defined (0-5 m and 5-10 m), and a zone without the reservoir influence or with final water table level more than 10 m depth. Finally, an aquifer monitoring program was defined, in order to follow the water table impact after the reservoir impoundment. According to this program, two weeks after the impoundment should be made the first field measurement. The periodicity should be monthly until the first three months, and, after that, quarterly until the end of the first year. The present study showed the viability of using Geographic Information System associated to mathematical models to predict modifications induced on the water table levels after a reservoir impoundment. This methodology is recommended as an important tool to be applied in other cases with the same problem.

Esta pesquisa objetivou mostrar a viabilidade de utilização do Sistema de Informação Geográfica (SIG) associado à modelagem matemática, como opção metodológica a ser aplicada no estudo das modificações induzidas no nível freático, após o enchimento de reservatórios. A área piloto escolhida foi a bacia de drenagem do rio Biritiba-Mirim, localizada na região do Alto Tietê, no Estado de São Paulo. O entendimento do funcionamento do sistema hidrogeológico, obtido por meio de dados de geologia, hidrogeologia, climatologia, poços existentes e sondagens executadas na área, subsidiou a elaboração do modelo conceitual. Na área, foram identificados dois tipos de aqüíferos: o Sedimentar, restrito às planícies fluviais e o Cristalino alterado, decorrente da alteração intempérica da rocha. Os fluxos locais da água subterrânea ocorrem em direção aos cursos d’água que constituem a malha de drenagem da bacia, enquanto que, regionalmente, as águas subterrâneas fluem na direção do rio Biritiba-Mirim. As informações do modelo conceitual foram, inicialmente, organizadas no Sistema de Informação Geográfica e, posteriormente, transferidas para o modelo matemático. Foi construído um modelo matemático para a bacia de drenagem do rio Biritiba-Mirim utilizando o programa tridimensional de diferenças finitas MODFLOW desenvolvido por McDONALD & HARBAUGH (1988). A calibração do modelo foi executada a partir de ajustes sucessivos, efetuados por meio do SIG e, posteriormente, aferidos no MODFLOW. Uma vez concluído o processo de calibração, procedeu-se à simulação do enchimento do reservatório, utilizando novamente o Sistema de Informação Geográfica para a entrada dos dados. A simulação, também realizada no MODFLOW, possibilitou delimitar as áreas nas quais os níveis das águas subterrâneas sofrerão maiores influências do reservatório, dando o subsidio necessário para a locação dos poços de monitoramento. Os dados coletados no período de um ano de monitoramento permitiram executar a verificação e eventuais correções do modelo. Com o modelo aferido, repetiu-se a simulação do enchimento do reservatório e, a partir do mapa potenciométrico resultante, foi elaborado o mapa de profundidades de níveis d’água subterrânea previstas para após o enchimento do lago, denominado de Mapa Previsional de Influência. Nesse mapa foram delimitadas duas zonas de influência (de 0-5 m e de 5-10 m) e uma zona sem influência do reservatório ou com profundidade final do nível freático superior a 10 m. Finalmente, definiu-se um programa de monitoramento potenciométrico do sistema aqüífero livre para execução em situação posterior ao enchimento do reservatório, a fim de avaliar o tempo e tipo de resposta do aqüífero livre ao processo de enchimento e efetuar a retroanálise das previsões. De acordo com programa definido, a primeira campanha de medição deverá coincidir com o início do enchimento do reservatório, a partir desta, o monitoramento deverá ser mensal até os três primeiros meses e, posteriormente, trimestral até completar um ano após o enchimento. A execução do presente estudo comprovou a viabilidade da aplicação do SIG, associado à modelagem matemática com fins previsionais, em escala de bacia de contribuição, para a avaliação das modificações induzidas no nível do aqüífero livre após o enchimento de reservatórios. Recomenda-se a metodologia aqui proposta como ferramenta a ser aplicada em outros locais que apresentem a mesma problemática. / The purpose of the current research was to demonstrate the viability of using Geographic Information System – GIS associated to mathematical models as a methodological option to be applied in the study of the water table elevation induced by dam reservoirs after their impoundment. The chosen area was the drainage basin of Biritiba-Mirim river, located in Alto Tietê area, in São Paulo State. The understanding of the hydrogeological system was acquired through geological, hydrogeological and climatological data. The surveys executed in the area, also allowed the construction of the conceptual model. In the area, two aquifers types were identified: the Sedimentary, restricted to the fluvial plains, and the altered Crystalline, due to the weathering. The regional groundwater flow was toward Biritiba-Mirim river, while the secondary drainage was a local groundwater discharge area. The conceptual model data was, initially, organized in a Geographic Information System and later transferred to the mathematical model. A mathematical model was built on the Biritiba-Mirim drainage basin using MODFLOW, a three-dimensional program of finite differences developed by McDONALD & HARBAUGH (1988). The model calibration was executed through successive trial-error process, using Geographic Information System as a input data and MODFLOW to evaluate results. After the conclution of the calibration process, the Biritiba-Mirim reservoir impoundment was simulated using Geographic Information System to input the new variable. The simulation, also accomplished in MODFLOW, made possible to limitate the main areas that will be impacted on their ground water levels. Using that map were located the monitoring wels. From the monitoring data, collected in a year period, it was possible to verify the model. The reservoir impoundment simulation was repeated. From the resulted potenciometric map, the groundwater final depths map was elaborated. In that map, named Predictional Influence Map, two influence zones were defined (0-5 m and 5-10 m), and a zone without the reservoir influence or with final water table level more than 10 m depth. Finally, an aquifer monitoring program was defined, in order to follow the water table impact after the reservoir impoundment. According to this program, two weeks after the impoundment should be made the first field measurement. The periodicity should be monthly until the first three months, and, after that, quarterly until the end of the first year. The present study showed the viability of using Geographic Information System associated to mathematical models to predict modifications induced on the water table levels after a reservoir impoundment. This methodology is recommended as an important tool to be applied in other cases with the same problem.

Les retenues de barrage sont l’objet d’enjeux sociétaux, économiques et environnementaux. Leur présence affecte le transit naturel de l’eau et de la charge sédimentaire associée. Selon les cycles hydrologiques et leur exploitation, la remobilisation des sédiments accumulés et des contaminants associés est plus ou moins marquée. Dans ce contexte, cette étude a pour principal objectif de déterminer l’évolution des teneurs, flux et spéciation des éléments métalliques au cours des phases d’accumulation et de remobilisation sédimentaire naturelles et influencées. Pour ce faire, une étude de terrain de 19 mois à l’amont et à l’aval de l’ouvrage a été effectuée en conditions courantes et événementielles d’exploitation. Le suivi de deux opérations de chasses d’hydrocurage, destinées à l’évacuation des sédiments de la retenue par ouverture des vannes de fond du barrage en période de hautes eaux, a notamment été réalisé. L’impact des différents paramètres physicochimiques (ratio solide/liquide, pH, potentiel redox, séchage) sur le devenir et la spéciation des éléments métalliques ainsi que les différents mécanismes associés ont quant à eux été évalués à l’aide d’expériences de laboratoire, d’études statistiques et de modélisation. Les résultats ont montré qu’en période d’exploitation courante, la présence de l’ouvrage induit une discontinuité amont/aval des teneurs, flux et partition des éléments métalliques, amplifiant notamment l’influence du pH sur leur spéciation et mobilité du fait de l’artificialisation des conditions d’écoulement. Lors des opérations d’exploitation événementielle par chasse d’hydrocurage, la modification des conditions de pH, d’oxydoréduction et de ratio S/L au sein du cours d’eau aval lors du passage de la charge sédimentaire augmente les teneurs en As, Fe et Mn solubilisés via des phénomènes de désorption et de dissolution des oxydes métalliques. Néanmoins, étant donné la faible mobilité des éléments métalliques et la stabilité des phases porteuses, les flux dissous restent minoritaires par rapport aux flux particulaires. La réalisation fréquente des opérations de chasse permet de minimiser les flux sédimentaire et métallique mis en jeu au cours du temps, limitant par conséquent son impact sur le cours d’eau aval. / Dam reservoir contexts concentrate social, economic and environmental issues. Their presence modifies both natural water and sediments continuity. Water level can be stable or fluctuate according to hydrological cycles and exploitation, leading to more or less pronounced sediments and associated contaminants remobilization. In such context, this work aims at studying spatio-temporal changes in concentrations, fluxes as well as speciation of metallic elements during natural and anthropologically-driven sediments accumulation and resuspension phases. For this purpose, a 19 months field survey was performed upstream and downstream from the dam during both routine and exceptional exploitation. The water and sediments quality during two sluicing events, performed in order to re-erode deposited reservoir sediments and flush them downstream through the bottom valves of the dam during high flows, were notably monitored. As for the influence of the main physicochemical parameters (i.e., solid/liquid ratio, pH, redox potential, drying) on metallic elements fate and speciation as well as the different processes involved, they were studied through laboratory experiments, statistical analyses and modeling. Results highlighted that during routine exploitation, dam presence leads to a significant discontinuity in metallic element dissolved concentrations, fluxes and speciation, mainly through pH changes magnified by water flow artificial lowering. During sluicing management, the high local pH, redox and S/L changes of the downstream water, mainly following maximum sediments release, enhance As, Fe and Mn solubilization through desorption or metallic oxydes dissolution. Nevertheless, given the overall low mobility of the metallic elements and bearing phases stability, dissolved fluxes remain far lower than particular ones. Recurrent sluicing management permits to minimize sediments and metallic fluxes, limiting toxicity towards aquatic biota.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21374号 / 農博第2298号 / 新制||農||1066(附属図書館) / 学位論文||H30||N5147(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 村上 章, 教授 藤原 正幸, 教授 渦岡 良介 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Cette thèse a pour objectif de caractériser les processus dominants dans l'évolution morphologique d'une retenue de forme allongée. Ces retenues sont caractérisées par une dimension longitudinale prédominante par rapport à la dimension transversale. La thèse s'est appuyée sur le cas de la retenue de Génissiat, située au cœur d'une série d'aménagements hydro-électriques sur le Haut-Rhône et soumise à des opérations régulières de chasses hydrauliques. Une analyse hydro-morphologique basée sur l'interprétation des évolutions morphologiques et des conditions d'écoulement a été réalisée. A partir de cette analyse, un découpage de la retenue en tronçons a permis de mettre en évidence la dynamique spatiale des sédiments au sein de la retenue. Une analyse de la dynamique spatio-temporelle du transport des sédiments a permis de quantifier et de caractériser les flux de transportés et leurs incertitudes. La contribution des processus associés au transport des différentes classes granulométriques (sables et sédiments fins) a alors été évaluée. Enfin, deux modèles numériques unidimensionnels ont été développés afin de simuler les processus dominants pour le transport des sédiments fins et des sédiments grossiers. Les résultats de modélisation ont montré la capacité des modèles à reproduire les évolutions morphologiques et les flux transportés, avec des valeurs simulées comprises dans les plages d'incertitude de mesure. La partie amont de la retenue apparait ainsi nettement dominée par le transport de sable alors que la partie aval est dominée par le transport de fines. Finalement, les modèles ont été appliqués pour tester différents protocoles de gestion de la retenue dans le but d'établir des règles d'exploitation permettant de limiter le comblement de la retenue et les impacts environnementaux à l'échelle d'évènements de chasse et sur le long terme / This PhD thesis aimed to characterize the main processes responsible for the morphological evolution of an elongated reservoir, characterized by predominant longitudinal dimensions. It was based on the case study of the Genissiat reservoir, located in a series of hydropower plants on the French Upper Rhone River and regularly subjected to flushing operations. A fluvial geomorphological analysis based on morphological evolutions and hydraulic conditions was performed. A longitudinal delineation of the reservoir allowed to highlight the spatial dynamics of the reservoir. Sediment fluxes in the reservoir and their uncertainties were quantified and qualified and evidenced the contribution of transport processes associated to sand and fine sediments. Two one-dimensional numerical models were developed to simulate the main processes for fine sediment and coarse sediment transport, respectively. Numerical results showed that these models were able to reproduce morphological evolutions and sediment fluxes, with differences between simulated and measured values lower than the measurement uncertainties. It appeared that the upstream part of the reservoir is dominated by sand transport while the downstream part of the reservoir is dominant by silt and clay sediment transport. Finally, the models were used to simulate predictive scenarios and to evaluate the impact of the operating rules on sediment dynamics. Some enhancements to current operating rules were proposed to limit reservoir sedimentation and downstream ecological impacts related to flushing events and long-term management

This work evaluates evolution changes of socio-economical structure and Territorial System of Ecological Stability (ÚSES) in Territory Zone. Territory Zone is meant nearer surround of river dam Hněvkovice, that is used for needs of technological water in JETE (nuclear power station Temelín). There can be found villages Buzkov, Dobřejovice, Hroznějovice, Jaroslavice, Jeznice, Kostelec, Litoradlice, Poněšice, Pořežany, Purkarec and Třitim. This work also solves evolution of number of population, age structure and employment from 1982 to 2001 as well as other specific development factors of this territory. The part of this work is the KES (Coefficient of the Ecological Stability) of the territory before and after the Hněvkovice dam was built. The basic characteristics of whole territory and list of historical interests is also important.