Dissertations / Theses on the topic 'Hydromorphologie'

Das Verständnis über die Ausprägung der Lebensgemeinschaften von benthischen Invertebraten in aquatischen Ökosystemen in Abhängigkeit von abiotischen Faktoren ist von grundlegender wissenschaftlicher Bedeutung und eine Voraussetzung für die Bewertung, den Schutz und die Wiederherstellung der ökologischen Integrität in Fließgewässern. Für die Erarbeitung von Abhängigkeiten zwischen der benthischen Lebensgemeinschaft, der Hydromorphologie und der Saprobie standen insgesamt 409 Datensätze in Form von Taxalisten des Makrozoobenthos zur Verfügung. Diese wurden mit Strukturgütedaten verschnitten und anhand uni- und multivariater statistischer Methoden analysiert. Folgende Ergebnisse konnten dabei erzielt werden: (a) es können sieben Einzelparameter der Gewässerstruktur identifiziert werden, die einen signifikanten Einfluss auf die benthische Biozönose ausüben, (b) die Fließgewässertypen 5 und 5.1 unterscheiden sich auf Basis des vorliegenden Datensatzes weder in der taxonomischen noch in der funktionalen Zusammensetzung der Makrozoobenthoszönose und (c) bei einer erhöhten saprobiellen Belastung überlagert der Einfluss der organischen Belastung die strukturellen Gegebenheiten. Für die Entwicklung und Anpassung effizienter Strukturgüteverfahren und die daraus resultierenden Monitoring- und Maßnahmenprogramme für ein integriertes Fließgewässermanagement ist die Auswahl ökologisch relevanter Parameter von immenser Bedeutung
The understanding about the development of benthic invertebrate communities as a function of abiotic influencing factors in aquatic ecosystems is of essential scientific relevance for the assessment of the ecological status of rivers and streams. For the development of interdependencies between benthic invertebrates, hydromorphology and saprobity, 409 species lists of the macroinvertebrates were provided. They were aggregated with morphological features and analysed with different uni- and multivariate statistical methods. On the basis of the used analyses, the following results were achieved: (a) seven ecological relevant morphological features with significant influence to benthic invertebrate community could be identified, (b) on the basis of the present database, the structural and functional composition of the benthic invertebrates can not be differ river type specific (type 5 and 5.1) and (c) if the saprobic pressure decrease, the organic pressure superpose the hydromorphology. The values of the biological attributes are low in spite of near natural morphological conditions. For an ecological efficiency stream habitat assessment, the identified relevant morphological parameters have to consider. The “morphological characteristic curves” are well describing the results of a local monitoring. This application-oriented instrument can be used for (a) the operationalisation of environmental objectives, (b) the development and adaption of monitoring strategies and (c) the derivation and prioritisation of ecological and economic efficiency measurements for an integrated river management

Das Verständnis über die Ausprägung der Lebensgemeinschaften von benthischen Invertebraten in aquatischen Ökosystemen in Abhängigkeit von abiotischen Faktoren ist von grundlegender wissenschaftlicher Bedeutung und eine Voraussetzung für die Bewertung, den Schutz und die Wiederherstellung der ökologischen Integrität in Fließgewässern. Für die Erarbeitung von Abhängigkeiten zwischen der benthischen Lebensgemeinschaft, der Hydromorphologie und der Saprobie standen insgesamt 409 Datensätze in Form von Taxalisten des Makrozoobenthos zur Verfügung. Diese wurden mit Strukturgütedaten verschnitten und anhand uni- und multivariater statistischer Methoden analysiert. Folgende Ergebnisse konnten dabei erzielt werden: (a) es können sieben Einzelparameter der Gewässerstruktur identifiziert werden, die einen signifikanten Einfluss auf die benthische Biozönose ausüben, (b) die Fließgewässertypen 5 und 5.1 unterscheiden sich auf Basis des vorliegenden Datensatzes weder in der taxonomischen noch in der funktionalen Zusammensetzung der Makrozoobenthoszönose und (c) bei einer erhöhten saprobiellen Belastung überlagert der Einfluss der organischen Belastung die strukturellen Gegebenheiten. Für die Entwicklung und Anpassung effizienter Strukturgüteverfahren und die daraus resultierenden Monitoring- und Maßnahmenprogramme für ein integriertes Fließgewässermanagement ist die Auswahl ökologisch relevanter Parameter von immenser Bedeutung.
The understanding about the development of benthic invertebrate communities as a function of abiotic influencing factors in aquatic ecosystems is of essential scientific relevance for the assessment of the ecological status of rivers and streams. For the development of interdependencies between benthic invertebrates, hydromorphology and saprobity, 409 species lists of the macroinvertebrates were provided. They were aggregated with morphological features and analysed with different uni- and multivariate statistical methods. On the basis of the used analyses, the following results were achieved: (a) seven ecological relevant morphological features with significant influence to benthic invertebrate community could be identified, (b) on the basis of the present database, the structural and functional composition of the benthic invertebrates can not be differ river type specific (type 5 and 5.1) and (c) if the saprobic pressure decrease, the organic pressure superpose the hydromorphology. The values of the biological attributes are low in spite of near natural morphological conditions. For an ecological efficiency stream habitat assessment, the identified relevant morphological parameters have to consider. The “morphological characteristic curves” are well describing the results of a local monitoring. This application-oriented instrument can be used for (a) the operationalisation of environmental objectives, (b) the development and adaption of monitoring strategies and (c) the derivation and prioritisation of ecological and economic efficiency measurements for an integrated river management.

L'Orge est une petite rivière de plaine fortement segmentée, du bassin parisien. En 2010, elle comptait en moyenne un clapet tous les kilomètres sur sa partie aval. Pour rétablir la continuité écologique du cours d'eau, le Syndicat de l'Orge efface progressivement ces ouvrages. L'objet de cette thèse est le suivi biogéochimique, hydro-sédimentaire et écologique d'un bief de l'Orge de 6 km où 3 clapets consécutifs ont été effacés.Les hauteurs d'eau dans la rivière ayant baissé, des bancs de vase ont été mis à l'air. Ces banquettes de sédiments subissent des séquences d'inondation/exondation au rythme des crues. Les transformations de l'azote et du soufre y sont particulièrement actives et dynamiques. Cependant, les faibles flux d'eau échangés (modélisation) limitent l'impact des banquettes sur la rivière. Des processus intenses de précipitation/solubilisation des sulfates, liés aux variations des niveaux d'eau, ont une importance non négligeable sur la dégradation de la matière organique et la production d'ammonium dans la banquette.La capacité de transport de sédiments de la rivière a fortement évolué suite aux effacements, ce qui se traduit par l'apparition d'une granulométrie plus grossière en fond de lit. Ont été évalué la nouvelle vitesse de transit des particules charriées et le temps nécessaire pour atteindre un nouvel équilibre du lit et des espèces biologiques qui y vivent. Les indicateurs biologiques montrent que les effacements améliorent l'habitabilité de la rivière.Ces suivis montrent l'impact positif des effacements de barrage sur une rivière de plaine, même si un suivi dans la durée reste nécessaire pour confirmer les évolutions mises en évidence.

Le 23 octobre 2000, la Directive Cadre sur l'Eau est adoptée par le Parlement Européen et établit un cadre pour une politique globale de la ressource en eau. Elle fixe comme principal objectif l'atteinte du " bon état écologique " des milieux aquatiques à l'horizon 2015 et s'appuie pour son évaluation sur deux critères : les qualités physico-chimique et écologique. L'aspect hydromorphologique est distingué comme soutenant la qualité écologique. Cette qualité hydromorphologique repose elle-même sur trois paramètres : le régime hydrologique, les conditions morphologiques et la continuité (faunistique et sédimentaire) des cours d'eau. À travers ce dernier point, la DCE vient de consacrer l'effacement des ouvrages transversaux. Si les " désordres " physiques et écologiques engendrés par les ouvrages en travers sont appréhendés, trop peu d'études se sont, pour l'heure, penchées sur les impacts de leur suppression. La recherche propose de rappeler de manière exhaustive les impacts des ouvrages transversaux sur les hydrosystèmes et de présenter les quelques études abordant les impacts inhérents à leur suppression. Puis, l'objectif est de caractériser et de quantifier précisément les conséquences hydrogéomorphologiques des effacements au niveau du lit et des berges de l'Yerres, rivière fortement anthropisée. On développe une méthodologie analysant l'évolution des composantes de la dynamique fluviale en contexte décloisonné. Nos résultats ont permis de mettre en évidence : 1) un abaissement systématique du niveau limnimétrique, 2) une contraction variable du chenal, 3) une augmentation des puissances spécifiques et de la capacité de transport de la rivière proportionnelle au degré de décloisonnement. Les valeurs de puissance spécifique dépassent localement le seuil de 35 W/m², laissant entrevoir des possibilités de réajustements morphologiques ; 4) une réactivation des processus érosifs affectant les berges pour des débits de crue inférieurs même au débit de pleins bords. Finalement on montre que ces réajustements hydromorphologiques sont effectifs sur l'Yerres aval et permettent localement un retour vers un état de référence ante-cloisonnement. Cependant les possibilités de restauration restent limitées par diverses contraintes qui s'imposent à cet hydrosystème anthropisé (risque de déconnexion de zones humides et de chenaux secondaires, déstabilisation du bâti riverain éventuellement patrimonial, impacts sur les usages), que les gestionnaires doivent nécessairement prendre en compte.

Les cours d’eau et leurs bassins versants sont des systèmes complexes et en équilibre dynamique. Si l’on connait qualitativement assez bien la plupart des processus dont ils sont le siège (ex. transport de matière organique et de sédiments, transformation des litières, etc…), il est beaucoup plus difficile d’en avoir une représentation pertinente à la bonne maille compte tenu de l’emboitement d’échelles des processus, des déterminants terrestres agissant sur les milieux aquatiques et surtout des différents facteurs de stress qui s’y combinent. Nous avons mené une exploration dont le but était de rechercher les causes souvent multiples de dégradation de l’état écologique, d’en connaître l’étendue spatiale et la gravité, pour être en mesure de recommander des actions efficaces de restauration. Dans la première partie de cette thèse, nous avons développé des modèles explicatifs de l’état écologique à large échelle capables de donner des réponses applicables aux échelles de décision et de gestion, à savoir européenne, nationale et régionale avec comme objectif principal de comparer les relations entre les pressions combinées représentées par l’occupation du sol et l'état écologique des cours d’eau de quatre pays européens: la France, la Slovaquie, l'Estonie, et le Royaume-Uni (Angleterre et Pays de Galles). Cette étude a permis (i) d’établir une hiérarchie des catégories d’occupation du sol influant sur l'état écologique, en particulier l'agriculture et l'urbanisation, (ii) d’identifier des tendances régionales dans ces relations pression-impact et (iii) d’évaluer le poids relatif de la pression à l‘échelle du bassin et du corridor rivulaire, et l’effet tampon des zones rivulaires suivant la nature de leur couverture. Dans une deuxième partie, nous avons construit un corpus de modèles capables d’expliquer d’une part la variabilité des indices biologiques utilisés dans les réseaux et de prédire d’autre part l’état écologique des masses d’eau françaises non suivies par le réseau de contrôle et de surveillance (RCS). Cette étude a permis de montrer que : (i) le facteur le plus impactant pour l’état biologique qu’il soit mesuré à partir des macroinvertébrés, des poissons ou des diatomées était la physico-chimie, suivie de l’occupation du sol et de l’hydromorphologie et (ii) l’utilisation de ces trois types de pressions permettait de développer des modèles prédictifs de l’état biologique robustes et fiables. Dans une troisième partie, nous avons voulu tester si les relations entre les pressions à l'échelle locale et l'état écologique étaient hiérarchiquement influencées par la typologie régionale (basée sur les caractéristiques géographiques naturelles et les forces motrices). Ceci nous a permis de montrer que la prise en compte d’une typologie basée sur les forces motrices des bassins versants ne remettait pas en cause la hiérarchie des effets des pressions sur la biologie. Enfin, dans une quatrième et dernière partie, nous avons développé une approche nouvelle qui propose de prendre en compte les connaissances sur l’organisation des échelles et sur les liens entre pressions et état écologique, en construisant et en analysant un modèle structurel qui a permis de relier entre elles des variables latentes correspondant aux pressions d’occupation du sol, hydromorphologiques et physico-chimiques et d’analyser in fine leur effet sur l’état écologique mesuré ici à travers l’I2M2. Le développement de ce modèle a montré : (i) l’effet important de l’occupation du sol sur l’hydromorphologie et sur la physico-chimie et l’effet indirect qui en découle sur les macroinvertébrés, (ii) l’effet de l’hydromorphologie sur la mosaïque de substrats, la dynamique des nutriments et de la matière organique, impliquant un effet indirect majeur sur les macroinvertébrés
The rivers and their watersheds are complex systems in dynamic balance. If processes acting in stream are relatively well known (organic matter and sediment transport, litter degradation, etc ...), it is much more difficult to have a relevant representation of this functioning considering the hierarchy of scales, land determinants affecting aquatic environments and combined multiple stressors. We conducted an exploration whose purpose was to seek the multiple causes of degradation of the ecological status, to know the spatial extent and severity and to be able to recommend effective restoration actions. In the first part of the thesis, we developed large-scale models, based on existing data, to give answers applicable to the decision and management scales, i.e. European, national and regional. The main was to compare the relationships between the combined pressures represented by land cover and the ecological status of running waters in four European countries: France, Slovakia, Estonia, and UK (England and Wales). This first study allowed us i) to establish the hierarchy of the major influences that impact ecological status, particularly agriculture and urbanisation, ii) to identify regional patterns in these pressure-impact relationships and iii) to evaluate the relative weight of the pressures acting at the basin and riparian corridor scales, and the possible buffering effect of riparian land cover. In the second part of the thesis, we built a corpus of models capable of explaining the variability of the biological indices used in the survey network and also predict the ecological status of non-monitored water bodies in France. This permits to demonstrate that : (i) the parameters characterizing the load of nutrients and organic matter had a predominant effect on the three compartments, followed by land use and hydromorphology, (ii) it is possible to build models capable of predicting ecological status that are efficient and easily transferable, using data of different scales that influence the functioning of hydrosystems. In the third part, we tested if the relationships between local scale pressures and ecological status are hierarchically influenced by regional patterns (such as natural physiographic and/or driving forces). Introducing hierarchical factors in multi-stress models can lead to slight variations in responses of organisms to pressures according to their natural characteristics and their driving forces acting at catchment scale. And in the last part, the purpose of our approach was to take into account the nested scale organisation and the links between anthropogenic pressures and river ecological status by building - and analysing the results of - a model based on the PLS path modelling method. This method can be used to simultaneously analyse the effects of latent variables corresponding to land-use, hydromorphological and physico-chemical pressures on the ecological status of rivers, synthetically measured in this study by the macroinvertebrate-based French biotic index for wadeable rivers (I2M2). The development of this model should allow us to demonstrate : (i) the importance of land use effect exerted on both hydromorphology and physico-chemistry and their translation as an indirect effect on biological condition of streams, (ii) that hydromorphological alterations had an effect on substrates structure and nutrients and organic matter concentrations implying that hydromorphology has a major indirect effect on macroinverteb

La St. Baume (Bouches du Rhône, Var ; France) est le plus méridional des massifs de la basse Provence carbonatée. Sa structure résulte de la reprise du chevauchement sud provençal (Eocène sup. ) Par la phase tectonique majeure ponto-pliocène. Ses structures géologiques complexes (w-e) sont recoupées orthogonalement par un drainage fluviatile (s-n). Cette disposition détermine un morcellement du drainage souterrain. La somme des débits atteint huit cents litres par seconde et les débits moyens des plus grosses sources sont inférieurs à deux cent litres par seconde. Ce massif possède tous les types de fonctionnement définis par A. Mangin. Son drainage s'effectue à 3 niveaux et selon 3 axes: vers le N. Vers des sources locales : vers la source orientale et occidentale la plus basse; vers la sources sous marines de Cassis. Des analyses hydrochimiques et bactériologiques montrent que ces eaux sont de grande qualité. Une relation entre l'altitude des sources et la valeur du coefficient de tarissement montre que les drainages aérien et souterrain sont indissociables. L'étude de la morphologie des bassins versants fluviatiles montre que leurs principales dimensions sont liées. Le drainage souterrain ne pouvant être abordé par l'analyse de sa morphologie, nous avons développé une approche plus théorique en nous appuyant sur les principes développés dans le cadre de la thermodynamique des phénomènes irréversibles. Les structures de drainage ont donc une cohérence qui doit servir a guider toute reconstitution. La St. Baume qui a subi plusieurs changements d'orientation de drainage est un vieux karst ou d'anciennes morphologies continuent a jouer un rôle dans le fonctionnement hydrologique actuel car ce karst n'a jamais été l'objet de soulèvements importants permettant une marginalisation de ces anciennes structures souterraines de drainage
Sainte Baume (Bouches du Rhône, Var ; France) is the most southern massif of lower carbonated Provence. Its structure results from resumption of south provencal overthrust by the tectonic major ponto-pilocene phase. Its complex geologic structures are cut at right angle by a fluviatile drainage s. N. This disposition determines a partition of underground drainage. Total outflow goes up to eight hundred litres per second and mean of major springs are modest. This massif includes all types of function as defined by A. Mangin. It is drained on three levels and according to three axes: n. Towards local springs; towards the oriental and occidental lower spring; towards sub-marine springs. Hydrochemical and bacteriological analyses show that these waters are of great quality. A relation between the springs altitude and the value of the exhaustion coefficient proves that underground and areal drainage cannot be dissociated. Morphological studies of fluviatile river basins show that their main dimensions are linked. As underground drainage cannot be analysed by a morphological study we have developed a more theoretical approach resting on the principles developed by thermodynamics of irreversible phenomena. Drainage structures thus have coherence which must guide all reconstitution: Sainte Baume which has undergone many changes in drainage orientation is an old karst. Ancient morphology continues to play a part in the actual hydrological function as this karst have never been subjected to major upheavals which would have excluded these ancient structures from the drainage pattern

L’objectif de la thèse est, tout d’abord, d’identifier et caractériser la trajectoire spatio-temporelle d’un petit cours d’eau périurbain de faible énergie, à travers l’exemple francilien de la Mérantaise (Essonne-Yvelines). Ces objets d’étude sont, en effet, trop souvent négligés par la communauté scientifique alors même que les enjeux environnementaux de restauration et de préservation écologique, préconisés depuis plusieurs décennies par la DCE, y sont importants (impacts de l’urbanisation et des aménagements anciens). Une approche croisée géohistorique et hydromorphologique a permis de reconstituerl’évolution passée et actuelle de la rivière : la vallée a été fortement aménagée depuis le Moyen-Âge par des équipements hydrauliques modestes mais ayant affecté plus de 80% du linéaire. Les moulins à eau ont été abandonnés au cours du 20ème siècle, libérant partiellement le chenal. Désormais, la trajectoire actuelle, marquée par des ajustements morphologiques significatifs récents, est moins commandée par les aménagements anciens que par les pressions anthropiques actuelles qui touchent le bassin versant(urbanisation, réseau de transports et de drainage, intensification de l’agriculture). Enfin, cette thèse est également l’occasion de s’interroger sur le caractère écologiquement pertinent et hydromorphologiquement durable des travaux de restauration des milieux aquatiques. Ce travail doctoral propose, par ailleurs, de considérer les opérations de restauration comme de nouveaux équipements de la rivière répondant à des besoins socio-politiques nouveaux et participants pleinement de la trajectoire fonctionnelle de la rivière
The objective of this research is, first of all, to identify and characterize the spatio-temporal trajectory of a small low energy periurban river, through the example of the Merantaise River located in the Seine Basin. These objects of investigation are too often neglected by the scientific community even though the environmental issues of ecological restoration politics, advocated for several decades by the WFD, are important (impacts of urbanization and ancient watermills). An interdisciplinary geohistorical and hydromorphological approach allowed to reconstruct the past and present evolution of the river: the valley has been heavily developed since the Middle-Ages by modest hydraulic equipment but has beenaffected on more than 80% of the channel. Water mills were abandoned during the 20th century, partially clearing the channel. Nowadays, the current trajectory is marked by recent significant morphological adjustments and is less controlled by old hydraulical structures than by current anthropogenic pressures affecting the watershed (urbanization, transport and drainage network, intensification of agriculture). Finally, this thesis is also an opportunity to question the ecologically relevant and hydromorphologically sustainable nature of ecological restoration. This doctoral work also proposes to consider restoration operations as new river facilities responding to new socio-political needs and fully participating of the river's functional trajectory

Les rapports entre sociétés et rivières sont marqués par des bouleversements environnementaux qui interrogent les modalités, plus ou moins institutionnalisées et systématisées, de la production de connaissances et de la définition de pratiques légitimes. Récemment, ces interpellations se sont affirmées et cristallisées autour de l’approche et des concepts portés par l’hydromorphologie. La plus grande considération de ce cadrage théorique au sein de modes de penser et d’agir engendre de nombreux remaniements. En découle notamment, la remise en question d’une gestion des cours d’eau basée sur leur maîtrise et leur stabilisation, au profit d’une approche privilégiant l’expression de la dynamique fluviale. Cette thèse propose un examen de la dynamique qui a permis d’ériger l’hydromorphologie en une préoccupation formalisée et prépondérante. Puis, elle s’attache à montrer, comment l’hydromorphologie traduit les évolutions des rapports entre sociétés et rivières au travers de trajectoires conjointes marquées par des pratiques, des matérialités et des adaptations réciproques. Elle entend également mettre en avant comment cette nouvelle configuration théorique et pratique perturbe, tout au moins à l’heure actuelle, ce qui paraissait légitime et rationnel, et nécessite une recomposition des valeurs et des intentionnalités que les communautés riveraines manifestent à l’égard des cours d’eau. Cette thèse rend finalement compte de la manière dont l’action publique et ses instruments s’adaptent et s’inventent au regard d’une plus grande prise en compte de l’hydromorphologie afin de tendre vers ce à quoi celle-ci invite : redéfinir les modalités d’une existence conjointe entre rivières et sociétés riveraines
The relationship between societies and rivers is marked by environmental changes that question the modalities, more or less institutionalized and systematized over time, used to generate knowledge and to define legitimate practices. Recently, these questions have emerged and crystallized around the approach and concepts supported by hydromorphology. The greater consideration of this theoretical framework within ways of thinking and acting leads to many changes. In particular it follows that river management based on the control and stabilization of rivers is challenged in favour of an approach based on the expression of the river dynamics. This thesis proposes, first, a review of the processes which helped made it into a formal and decisive issue. Then the thesis aims to show through how hydromorphology represents and reflects the changes in the relationship between people and rivers through joint trajectories marked by practices, materiality and reciprocal adaptation throughout unique timescales and spatiality. It also intends to highlight, through an analysis of the representations of hydromorphological functioning of the river, how this new theoretical and practical configuration disturbs, at least currently, what seemed legitimate and rational until this day, and requires a restructuring of values and intentionality that riparian communities display in respect of watercourses. Finally, this thesis accounts for how public policy and its instruments are faced with new expectations, both cognitively and operationally, how they adapt and reinvent themselves in the light of a greater consideration of hydromorphology towards what it calls for: redefining the terms of a joint existence between the rivers and riparian societies

L’Orge est une petite rivière de plaine fortement segmentée, du bassin parisien. En 2010, elle comptait en moyenne un clapet tous les kilomètres sur sa partie aval. Pour rétablir la continuité écologique du cours d’eau, le Syndicat de l’Orge efface progressivement ces ouvrages. L'objet de cette thèse est le suivi biogéochimique, hydro-sédimentaire et écologique d'un bief de l’Orge de 6 km où 3 clapets consécutifs ont été effacés.Les hauteurs d’eau dans la rivière ayant baissé, des bancs de vase ont été mis à l'air. Ces banquettes de sédiments subissent des séquences d’inondation/exondation au rythme des crues. Les transformations de l’azote et du soufre y sont particulièrement actives et dynamiques. Cependant, les faibles flux d’eau échangés (modélisation) limitent l’impact des banquettes sur la rivière. Des processus intenses de précipitation/solubilisation des sulfates, liés aux variations des niveaux d’eau, ont une importance non négligeable sur la dégradation de la matière organique et la production d’ammonium dans la banquette.La capacité de transport de sédiments de la rivière a fortement évolué suite aux effacements, ce qui se traduit par l’apparition d'une granulométrie plus grossière en fond de lit. Ont été évalué la nouvelle vitesse de transit des particules charriées et le temps nécessaire pour atteindre un nouvel équilibre du lit et des espèces biologiques qui y vivent. Les indicateurs biologiques montrent que les effacements améliorent l’habitabilité de la rivière.Ces suivis montrent l’impact positif des effacements de barrage sur une rivière de plaine, même si un suivi dans la durée reste nécessaire pour confirmer les évolutions mises en évidence
Orge is a lowland river from Seine’s watershed, France. In 2010, Orge River was highly segmented with on average one dam (< 2m) every kilometer in downstream part. To restore the ecological continuity of the river, the “Syndicat de l’Orge” gradually removes these little dams. The purpose of this thesis is the monitoring of hydro-morphology, biogeochemistry and ecological of a section of 6 km of Orge where 3 consecutive dams have been removed in spring 2010.After the water level decrease, some previously drowned sediment deposits appear along the river bank. These sediment banks are frequently inundated by high flows. Nitrogen and sulfate processes are very intense onto these banks. However, a model shows that water fluxes limited biochemical impact of sediment banks on the river. Intense precipitation/solubilization sulfate processes, link with water level variations, have a significant importance on organic matter degradation and ammonium production in sediment banks.The sediment transport capacity of the river has changed significantly after dam removal. It results in an increase of the maximum transportable diameter of the river, leading to the appearance of a coarser bed in-situ. It was possible to evaluate the new transit speed of particles carried along and highlight the time required to reach a new equilibrium of the bed and the biological species that live there. Biological indicators show that removals enhanced the livability of the river.All these studies show the positives impacts of dam removal on a lowland river, even if a monitoring in time is still needed to confirm the first developments highlighted here

Thesis (M.S.) -- University of Maryland, College Park, 2004.
Thesis research directed by: Dept. of Plant Science and Landscape Architecture. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

Ce travail s’inscrit dans le cadre d’un projet LIFE+ qui vise à restaurer le fonctionnement hydromorphologique d’un hydrosystème rhénan. Une étude planimétrique couplée à des analyses hydromorphologiques et sédimentologiques ont permis (i) d’améliorer la compréhension des dynamiques d’ajustement passées et (ii) d’identifier les principales limites du projet. Les évolutions morphologiques post-restauration ont été suivies à l’aide d’une combinaison de méthodes géodésiques et géomorphologiques afin de déterminer précisément les volumes déposés / exportés à différentes échelles spatio-temporelles. Enfin, la thermographie infra-rouge aéroportée a permis de mettre en évidence les liens entre la répartition spatiale des anomalies thermiques, les caractéristiques morphodynamiques et les héritages géomorphologiques. L’approche interdisciplinaire développée dans ce travail a permis de guider les choix opérationnels pour optimiser le suivi et l’évaluation des restaurations fonctionnelles futures
This study is part of a LIFE+ project which aims to restore hydromorphological functioning of a Rhine hydrosystem. A planimetric study combined with hydromorphological and sedimentological analysis allowed to (i) improve understanding of past adjustment dynamics and (ii) identify main limitations of the project. Post-restoration morphological changes were monitored by geodesic and geomorphological methods combination in order to determine accurate volumes of sediment deposited / exported at different spatio-temporal scales. Finally, airborne thermal-infrared was used to highlight the relationship between spatial distribution of thermal anomalies, morphodynamic characteristics and inherited geomorphological features. Interdisciplinary approach leaded in this study was able to guide decision-makers choices in order to optimise the monitoring and assess future functional restorations

Conventional hydrological compartmental models have been shown to exhibit a high degree of uncertainty for predictions of peak flows, such as the design floods for design of hydropower infrastructure. One reason for these uncertainties is that conventional models are parameterised using statistical methods based on how catchments have responded in the past. Because the rare occurrence of peak flows, these are underrepresented during the periods used for calibration. This implies that the model has to be extrapolated beyond the discharge intervals where it has been calibrated. In this thesis, hydromechanical approaches are used to investigate the properties of stream networks, reflecting mechanisms including stage dependency, damming effects, interactions between tributaries (network effects) and the topography of the stream network. Further, it is investigated how these properties can be incorporated into the streamflow response functions of compartmental hydrological models. The response of the stream network was shown to vary strongly with stage in a non-linear manner, an effect that is commonly not accounted for in model formulation. The non-linearity is particularly linked to the flooding of stream channels and interactions with the flow on flood-plains. An evaluation of the significance of using physically based response functions on discharge predictions in a few sub-catchments in Southern Sweden show improvements (compared to a conventional model) in discharge predictions – particularly when modelling peak discharges. An additional benefit of replacing statistical parameterisation methods with physical parameterisation methods is the possibility of hydrological modelling during non-stationary conditions, such as the ongoing climate change.
QC 20101022

With the formal adoption of the Water Framework Directive in 2000, into European legislation it committed all member states to ensure that all inland waterbodies should reach good ecological status by 2015. As a result examination of the influence of hydromorphology on the ecological health of riverine ecosystems has become an increasingly important priority for statutory monitoring agencies such as the Environment Agency of England and Wales and equivalents in other parts of the UK. It is anticipated that by increasing our understanding of the role that hydromorphological processes play in shaping river habitats and the ecosystems that they support, river management strategies can be developed that will help lead to waterbodies achieving good ecological status. In this thesis, the influence of river hydromorphology and instream channel management activities on instream macroinvertebrate communities is explored. A two-scale approach was used at a regional macro-scale and local / catchment micro-scale. The macro-scale study examines the ecological, hydrological and geomorphological data for 88 river reaches located within the Environment Agency , Anglian Central and Anglian Northern regions, over a twenty year period (1986-2005). At the micro-scale two sub-catchments were selected, the River Bain and River Lymn, both located in Lincolnshire, England for detailed investigation. The micro-scale study was undertaken using ecological, hydrological and geomorphological data collected over three successive seasons (Autumn 2008, Spring 2009 and Summer 2009) enabling the seasonal variations and the influence of both stream size and habitat biotope on macroinvertebrate community composition and structure to be explored. The hydromorphological characteristics and condition of the rivers were quantified using ecologically relevant hydrological indices, calculated from flow discharge paired with geomorphological indices from River Habitat Survey data. The response of the instream macroinvertebrate communities was examined using a range of ecological indices including the Lotic-invertebrate Index for Flow Evaluation (LIFE). The results of the macro-scale investigation demonstrate that the macroinvertebrate community is directly influenced by instream hydromorphology and the level of anthropogenic modification. The micro-scale study highlights important differences in macroinvertebrate communities associated with instream habitat / biotope composition. The quantification of river hydromorphology, with the use of ecologically relevant hydrological indices and geomorphological indices, derived from River Habitat Survey data, is discussed with regards its ability to help explain the structure and composition of macroinvertebrate communities within highly managed /regulated riverine ecosystems. The implications of this research for river managers and for implementing river restoration and rehabilitation schemes are explored.

River hydromorphological characterization is an important requirement for modern river management. The process-based river characterizations which are well established in fluvial geomorphology are location-specific and highly demanding in terms of resource and expertise, and their routine application for regional or national river characterizations is not feasible at the present. Reviewing current understanding of river geomorphic processes and making use of novel datasets, such as DEM, and tools, such as GIS, this work tests the feasibility of providing characterizations of hydromorphology that require moderate resources and are potentially applicable at regional or national scale. A framework to characterize river hydromorphology from specific map derived geomorphic controls (namely channel gradient, bankfull flow, specific stream power, Strhaler stream order and degree of channel confinement) is successfully developed. These controls are shown to be important in the characterization of channel types, to be consistently inter- connected in a hierarchical framework, and to affect frequency and typologies of channel forms. Stream power emerges as a dominant driver of sediment transport and floodplain formation and as an important indicator for characterizing channel sensitivity to erosion and deposition. The proposed characterization of hydromorphology uses automatic procedures of GIS and statistical analysis and demonstrates that these are promising for regional applications. Our understanding of the links between hydromorphology and ecology are also limited. This thesis presents an application of structural equation modelling (SEM) to explore the ecology of benthic macroinvertebrate communities in riverine ecosystems using national-scale biological, water quality and physical habitat data. The statistical model identifies a nurnber of links between the degree of organic pollution, alkalinity, physical habitat conditions, and the distribution of benthic macro invertebrates. SEM develops a confirmatory approach that it requires a-priori, explicit III ---= formulations of cause-effect relationships at the model conceptualisation stage. SEM is shown to address a number of the challenges related to multicollinear datasets (common in ecology), where interpretations based on statistical association alone can be problematic. IV

L'objectif de cette thèse était d'évaluer l'effet des changements globaux sur les milieux aquatiques. L'analyse exploratoire des bases de données d'occupation des sols, de physico-chimie, d'hydromorphologie, de diatomées dans les cours d'eau du bassin Adour-Garonne et de diatomées en Guyane a mis en évidence : 1) l'effet du changement global sur la qualité des eaux marquée par la hausse des températures et une atténuation sensible de l'eutrophisation ; 2) l'importance prépondérante des patrons d'occupation des sols à l'échelle du bassin versant ; 3) la persistance des diatomées et le changement des caractéristiques des communautés périphytiques face aux conditions de stress extrême dues à l'orpaillage en Guyane. Ces résultats ont démontré leurs valeurs quant à leurs potentiels de transfert vers les domaines de "la recherche appliquée" en proposant : 1) un référentiel temporel de la qualité chimique des eaux du bassin Adour-Garonne ; 2) l'intégration des patrons de l'occupation des sols à l'échelle du bassin versant dans le développement de nouveaux outils de bio-indication ; 3) la mise au point d'un indice diatomique générique basé sur les capacités motrices des diatomées et destiné au contexte guyanais
This thesis aimed at assessing the effect of global changes on aquatic ecosystems. The exploratory analysis of the land cover patterns, physicochemical, hydromorphological, and diatom databases in the Adour-Garonne basin and the diatom flora of streams in French Guyana highlighted: 1) the effect of the global changes on the water quality characterized by the temperature increase and the significant mitigation of eutrophication ; 2) the strongest influence of the land cover patterns at the catchment scale ; 3) the persistence of the diatom flora and the change of community structures facing extreme stress due to gold mining ; These results testified their importance as for their potential transfers towards the fields of "applied research", particularly proposing: 1) a temporal reference frame of the chemical water quality of the Adour-Garonne basin ; 2) to integrate the land cover patterns extracted at the catchment scale in order to improve or develop new biomonitoring tools ; 3) the development of a new generic diatom index appropriate to the French Guyana context based on the diatom motility abilities

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
This study aimed to evaluate the stream hydromorphological Guaraíra through the Bavarian method. The basin of the creek is located within the catchment area of Gramame, the southern portion of the state of Paraíba. Therefore, the creek was divided into 47 sections of 100 meters. During the survey of the characteristics of the stream was possible to observe the level of anthropogenic modification along its route. These surveys take into account the dynamics of river and plain and with the junction of the dynamics is obtained modification degree ranging from 1 (no change) to 7 (completely changed), based on the use of the method Bávaro. The creek Guaraíra has 81% of its route unchanged, despite being in a watershed with 33.63% of its area modified crops of sugar cane and pineapple. The 19% change were due to engineering works and, as previously mentioned, sugarcane also influenced this change in the natural state. With the method, it is clear that investments for restoration of local anthropogenic are more effective due to the division of the stream in patches. Thus, save yourself money and time by acting at the core of the problems.
Este trabalho teve como objetivo a avaliação hidromorfológica do riacho Guaraíra, através do método Bávaro. A bacia hidrográfica do riacho está localizada dentro da bacia hidrográfica do Gramame, porção sul do Estado da Paraíba. Para tanto, o riacho foi divido em 47 trechos de 100 metros. Durante o período de levantamento das características do riacho foi possível observar o nível de modificação antrópica ao longo de seu percurso. Esses levantamentos levaram em consideração as dinâmicas do rio e da várzea e com a junção das dinâmicas se obtém o grau de modificação que varia de 1 (inalterado) a 7 (completamente alterado), a partir da utilização do método Bávaro. O riacho Guaraíra possui 81% do seu percurso inalterado, apesar de estar em uma bacia hidrográfica com 33,63% de sua área modificada pelas culturas da cana de açúcar e do abacaxi. Os 19% de alteração foram devido, a obras de engenharia e, como já citado anteriormente, a cana de açúcar também influenciou nessa alteração do estado natural. Com o método, fica claro que investimentos para restauração de locais antropizados são mais eficazes, devido à divisão do riacho em trechos. Dessa forma, economizam-se recursos financeiros e tempo agindo no cerne dos problemas.

This thesis deals with the assesment of morphological and ecological conditions of six Italian alpine rivers. Odonata (dragonflies) were chosen as bioindicators to assess the ecological status of river corridors while the assessment of th morphological status of the study cases was performed by using the Morphological Quality Index (MQI) Dragonflies demonstrated to be an effective bioindicator. The results also indicated a significant correlation between MQI and OQI and demonstrated the importance of river processes as drivers for the maintenance of a high diversity of habitats and species within the river corridor.
Questa ricerca ha come tematica la valutazione delle condizioni morfoogiche ed ecologiche di sei fiumi alpini italiani. Gli Odonati (Libellule) sono stati scelti, dopo una fase di ricerca bibliografica, come bioindicatore per valutare lo stato ecologico del corridoio fluviale. mentre la valutazione delle stato morfologico è stata effettuata utilizzando l'Indice di Qualità Morfologica (IQM). Gli Odonati hanno dimostrato di essere un valido bioindicatore. I risultati ottenuti indicano una correlazione significativa tra i valori degli indici IQM ed IQO, a dimostrazione dell'importanza dei processi geomorfologici quali driver fondamentali per il mantenimento di un'elevata diversità di habitat e di specie all'interno del corridoio fluviale.

En France, les récentes évolutions réglementaires (DCE, 2000 ; LEMA, 2006) obligent à assurer une certaine continuité sédimentaire au droit des barrages. L’exigence se pose singulièrement dans le massif du Morvan, où une dizaine de barrages se sont installés depuis le milieu du XIXe siècle. Les questionnements y sont complexes : plusieurs des cours d’eau sur lesquels les ouvrages ont été édifiés ont été assez peu étudiés (lit plat de moyenne énergie à substrat grossier mixte). En outre, les systèmes fluviaux étudiés – l’Yonne supérieure, la Cure et le Chalaux – sont marqués par une anthropisation ancienne, caractérisée notamment par des usages multiples antérieurs aux barrages (moulins, flottage du bois). L’énergie de ces rivières, en partie régie par les barrages, est un facteur important mais insuffisant pour comprendre le charriage actuel. Celui-ci s’avère particulièrement influencé par certains paramètres morphologiques (substrat très grossier, structures sédimentaires, pente). Or les conditions morphologiques actuelles paraissent largement résulter de plusieurs décennies de modification des apports liquides et solides par les barrages. Leurs effets sur les processus fluviaux doivent donc être appréhendés à plusieurs échelles temporelles. Les travaux indiquent qu’ils dépendent également des influences héritées des anciens usages hydrauliques. La trajectoire hydromorphologique passée de la rivière semble aussi jouer sur les impacts morpho-sédimentaires qui ont pu être observés à la suite d’un démantèlement de barrage. Plutôt qu’une table rase ou un retour en arrière, les barrages ou leur démantèlement représentent ainsi davantage une nouvelle évolution de la trajectoire fluviale, faite de ruptures, de continuités et de mutations
In France, recent regulatory developments (WFD, 2000; LEMA, 2006) require sediment continuity across the dams to be ensured. This requirement is particularly acute in the Morvan massif, where a dozen dams have been installed since the middle of the 19th century. The questions are complex: several of the rivers on which the structures have been built have only been poorly studied (medium energy plane bed with mixed coarse substrate). In addition, the fluvial systems - the Upper Yonne, the Cure and the Chalaux - are marked by a long anthropogenic influence, characterized in particular by multiple uses prior to the dams (mills, log driving). Those rivers’ energy, partly governed by the dams, is an important factor but insufficient to understand current bedload transport. The latter is indeed significantly influenced by certain morphological parameters (very coarse substrate, sedimentary structures, slope). However, current morphological conditions appear to be largely the result of several decades of disturbance in liquid and solid inputs by dams. Their effects on river processes must therefore be understood on several time scales. The study indicates that they also depend on the influences inherited from previous hydraulic uses. The past hydromorphic trajectory of the river also seems to influence the morpho-sedimentary impacts that were observed following a dam removal. Rather than a clean slate or a step backwards, dams or their removal thus represent a new evolution of the river trajectory, made up of ruptures, continuities and mutations

A l'approche des échéances fixées par la Directive Cadre européenne sur l'Eau (DCE 2000), les actions de restauration se sont multipliées sur les cours d'eaux européens. Cependant, peu d'études ont été menées en parallèle pour évaluer les bénéfices apportés par de telles opérations aux biocénoses. En outre, bien que l'évaluation de la qualité écologique des cours d'eau soit de plus en plus alimentée par des approches fonctionnelles (dont l'utilisation des traits biologiques des invertébrés benthiques est un axe majeur), les retours d'expériences des opérations de restauration sont majoritairement basés sur les réponses taxonomiques des communautés aquatiques. Les objectifs de ce travail de thèse sont (i) de caractériser et de comparer les réponses spécifiques des communautés macrobenthiques à différentes actions de restauration physico-chimique et hydromorphologique et (ii) d'évaluer la pertinence de différentes approches basées, soit sur la taxonomie, soit sur les traits biologiques, dans le diagnostic de récupération des communautés d'invertébrés benthiques. Pour répondre à ces objectifs, deux sites d'un même cours d'eau méditerranéen, le Vistre (Gard), ont été étudiés. Le premier a fait l'objet de travaux de restauration hydromorphologique en 2004 et les réponses des assemblages d'invertébrés ont été étudiées simultanément sur six stations restaurées et trois stations non restaurées (canalisées) de 2008 à 2010. Sur le deuxième site, situé 5 km en aval, nous avons suivi la dynamique de récupération des communautés benthiques suite à une levée de pression physico-chimique (réduction des apports en azote et phosphore) imputable à l'arrêt du rejet d'une ancienne station d'épuration (STEP) et la mise en service d'une nouvelle STEP plus performante, 1 km en aval. Il a été montré que les indices basés sur des critères taxonomiques réagissent rapidement à la réduction des apports en nutriments mais ne traduisent pas une reprise complète du fonctionnement des communautés d'invertébrés. Au contraire les métriques basées sur les traits biologiques des invertébrés mettent en évidence une récupération biotique plus progressive qui n'atteint toutefois pas les valeurs attendues dans des conditions dites « de référence ». L'évaluation de la récupération des communautés d'invertébrés basée sur les profils de traits biologiques affiche également une meilleure corrélation avec les caractéristiques hydromorphologiques des stations en fonctions des travaux de restauration qu'elles ont, ou non, subis. L'utilisation des traits biologiques permet en outre de fournir des explications mécanistes aux processus de récupération des communautés d'invertébrés. Dans un contexte de pressions multiples, les réponses des communautés d'invertébrés ont souligné la nécessité d'agir à la fois sur la qualité physico-chimique de l'eau et le fonctionnement hydromorphologique du cours d'eau pour améliorer la qualité globale du système et permettre une récupération optimale des communautés. Les enseignements tirés de l'étude du Vistre ont été examinés afin de (i) dégager des implications concrètes pour le développement d'un outil d'évaluation du gain écologique par des opérations de restauration et (ii) soumettre des éléments d'aide à la décision dans le choix des actions de restauration à mener, et l'optimisation de leur suivi
The implementation of the European Water Framework Directive (WFD, 2000) has promoted the rapid development of many stream restoration programmes. However, very few studies have tried to improve the understanding of how anthropogenic pressure mitigation efforts contribute to the ecological recovery of streams. Moreover, available feedbacks have mainly focused on the taxonomic responses of aquatic communities. Nowadays, the assessment of stream ecological quality is increasingly driven by functional approaches, including the use of biological traits of benthic invertebrates. The main goal of my PhD work has been to characterize the specific responses of benthic macroinvertebrate communities to different restoration actions implemented to reduce nutrient inputs or to improve stream hydromorphological conditions, and to compare such actions using different approaches (taxonomic and functional). Two sections of the Vistre River (south France) were studied. On a 3 km-long river section, we have surveyed the invertebrate assemblage recovery during a four year period including the commissioning of a new Waste Water Treatment Plan (WWTP) equipped with biological treatment capable of significantly reducing N, P, and C inputs in the River. Five kilometres upstream, a 2 km-long reach was morphologically restored, including remaindering work, riparian vegetation planting and pebble input. Invertebrate assemblages were assessed simultaneously on six restored sites and three canalized, non-restored sites during three years. Our results have shown that among the metrics that reflect community recovery to nutrient input reduction, those based on taxonomic criteria respond faster than trait-based ones, but do not imply a complete recovery of invertebrate community functioning. Community recovery assessment based on biological traits has demonstrated also a better correlation with site hydromorphological characteristics which varied with restoration works. Moreover, trait-based approach allows a better explanation of the functional mechanisms that occur in benthic assemblages after chemical water quality or hydromorphological characteristic improvement. In a multi-stressor context, invertebrate community responses to different restoration actions have underlined the need for acting on both water chemical quality and hydromorphological environment to improve global stream quality and to allow convenient biological community recovery. Lessons from the Vistre River study have been examined to (i) identify practical implications for the development of an assessment tool for evaluating the ecological gain provided by restoration actions, and (ii) give elements to help managers in optimizing the definition and monitoring of restoration actions

The final thesis is focused on assessing the current state of hydrological system in the watershed area Jankovice stream and on draft proposal of food protection measures of the village Jankovice. In the first part of the thesis, there is documented the current situation Jankovice stream, its appreciation and draft measures for a improvement the current state. In the following part, there is the elaboration of the sediment transport balance in the stream. In the last part of the final thesis, there is documented the current state Jankovice stream in the village Jankovice and the stream regulation is designed for the purpose of flood protection of the village.

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The negative impacts caused by the use of process and land use on the banks of rivers and floodplains have been deteriorating the water health conditions, the environment and effect on landscapes. In urban areas, in particular, it is observed the degradation of rivers and water quality and aquatic biota. The interest in restoring ecosystems of waterways, both in urban and rural areas, is expanding worldwide, especially in developed countries. Similarly, areas of occupation in the coastal zone, those which tend to larger and denser occupation, have been a main concern of many governments. Therefore, models of environmental assessment of rivers have been developed and refined to allow the diagnosis and the selection of river restoration actions. The German method, called Mapping and assessment methods for the structure of Waters, developed in Bavaria, is used to map the quality of watercourses structure as a measure of its ecological integrity and indicates whether it is capable of supporting the dynamic processes of its bed. For the coastal zone, the Orla project’s methodology, developed by the Ministry of Environment of Brazil, uses the landscape units as elements of analysis in terms of urban occupation and provides grants for landscape analysis beyond the river limits and may complement fluvial analysis. Both methodologies contribute to perform a broader diagnosis of the current situation of environmental degradation, and may indicate which stretches and landscape units would need intervention to seek restoration or rehabilitation of these areas. In this work, these models were used to map the quality of the riverbed structure concerning its morphology, including the dynamics of the main river and the dynamics of wetlands, and also the marginal areas of low Jaguaribe River in its bed in the municipalities of João Pessoa and Cabedelo, on the south coast of the state of Paraíba. The results showed stretches of the river ranging from a totally altered state to little changed, concerning the stretch and the side occupation of the river channel. The extended marginal areas were classified into three types A, B, C of the Orla project, showing conformity with the classification obtained from the river system.
Os impactos negativos causados pelo processo de uso e ocupação do solo nas margens e planície de inundação dos rios vêm deteriorando as condições de salubridade das águas, do ambiente e com repercussão nas paisagens. No meio urbano, em particular, se observa a degradação dos rios e da qualidade da água e da biota aquática. O interesse em restabelecer os ecossistemas dos cursos d’água, tanto nas áreas urbanas quanto na rural, está se expandindo em todo o mundo, especialmente nos países desenvolvidos. De forma semelhante, a ocupação de áreas na zona costeira, as que apresentam tendências de maiores e mais densas ocupações, tem sido objeto de preocupação de diversos governos. Assim, modelos para avaliação ambiental de rios têm sido desenvolvidos e aperfeiçoados para permitir o diagnóstico e a seleção de ações de restauração fluvial. O método alemão, denominado Mapping and assessment methods for the structure of Waters, desenvolvido na Bavária, é utilizado para o mapeamento da estrutura da qualidade dos cursos d’água como medida da sua integridade ecológica e indica se o mesmo é capaz de suportar os processos dinâmicos de seu leito. Para a zona costeira, a metodologia do projeto Orla, desenvolvida pelo Ministério do Meio Ambiente do Brasil, se utiliza das unidades de paisagem como elementos de análise em termos de ocupação urbana e oferece subsídios para a análise da paisagem além dos limites fluviais, podendo complementar a análise fluvial. Ambas as metodologias contribuem para se realizar um diagnóstico mais amplo da situação atual de degradação ambiental, e podem indicar em quais trechos e unidades paisagísticas haveria necessidade de intervenção buscando a restauração ou requalificação dessas áreas. Neste trabalho, foram utilizados esses modelos para o mapeamento da estrutura da qualidade do leito fluvial, referente a sua morfologia, compreendendo a dinâmica do rio principal e a dinâmica das várzeas, além das áreas marginais do baixo rio Jaguaribe em seu antigo leito nos municípios de João Pessoa e Cabedelo, na zona costeira Sul do estado da Paraíba. Os resultados apontaram trechos do rio variando do estado totalmente alterado a pouco alterado, segundo o trecho e a ocupação lateral da calha fluvial. As áreas marginais estendidas foram classificadas nas três tipologias A, B, C do projeto Orla, apresentando concordância com à classificação obtida do sistema fluvial.

This thesis deals with hydroecological monitoring of watercourses. The HEM – Hydroecological monitoring is part of evaluation of status of watercourses, which is a requirement of the European Water Framework Directive. The content of this thesis is firstly to find out the status monitoring of hydromorphological quality of watercourses in the Czech Republic and a subsequent survey of methodology HEM. The aim of this thesis is comparison with the older methodologies and ways to improve the practical implementation of monitoring on smaller waterways. Measurement and knowledge will be applied to Troubsko creek.

Rivers and their catchments are under mounting pressure from direct channel modification, intensification of land use, and from a legacy of decades of channelisation. Recent legislation, in the form of the EU Water Framework Directive, places a greater emphasis on the management of water bodies as holistic systems, and includes the explicit consideration of hydromorphological quality, which describes the hydrologic and geomorphic elements of river habitats. These are defined specifically as hydrological regime, river continuity and river morphology. This appreciates that sediment and flow regimes, along with the channel structure, provides the 'template' on which stream ecological structure and function is built. Invertebrate fauna contribute significantly to the biodiversity of rivers, and often form the basis of monitoring river health. However much of the fundamental ecological knowledge base on the response of invertebrates to hydromorphological change needed to make informed decisions and accurate predictions, is either lacking, inadequate or contradictory. This thesis addresses some of the key potential shortcomings in recent bio-assessment that others have alluded to, but which have rarely been explored in the context of direct channel manipulations. By using two case studies of, realignment in a natural upland catchment, and flood protection engineering in an urban stream, this study investigates the sensitivity of hydromorphological impact assessment methods that rely on biodiversity patterns of benthic riverfly (Ephemeroptera, Plecoptera and Trichoptera) larva. This work employed widely used biomonitoring indices of benthic riverfly larva abundance, species richness, alpha and beta diversity, and community composition, applied over a range of spatial scales, in combination with spatially contemporaneous physical habitat data, to describe and explain community changes in response to disturbance, and patterns of natural variation. The effects of restoration were investigated using a high degree of sample replication within channels and across the wider catchment, as well as contrasting spring and autumn seasons. To assess change in a small urban channel, approaches that explicitly consider spatial elements of community data, using spatial eigenvectors analysis, were applied to spatially detrend community data and directly investigate spatial patterns. Restoration of the Rottal Burn was found to be successful in restoring habitat diversity and geomorphic processes, and in turn increasing reach scale species richness and beta diversity through the gradual arrival of rare and specialist taxa into novel habitats. Catchment scale replication revealed high variation in diversity indices of modified and undisturbed streams, and a strong temporal pattern related to antecedent flow conditions. Channels with greater habitat heterogeneity were able to maintain high gamma diversity during times of high flow stress by providing a number of low flow refuges along their length. The urban Brox Burn had surprisingly high riverfly richness and diversity driven by small scale hydraulic heterogeneity, created by bed roughness resulting in a range of microhabitats. Riverfly community responses to direct channel dredging could not be detected by measurements of average richness and diversity, however distinct changes were seen in gamma diversity, the identity of community members and their arrangement among sample patches. Impacts of sediment pollution release due to engineering were short lived and apparently had little detrimental impact on biodiversity. Strong spatial patterns of community assembly on the stream bed were uncovered, relating to longitudinal, edge and patchy patterns. Significant habitat drivers of community composition were confounded by high amounts of spatial autocorrelation, especially hydraulic variables. Due to the strongly physical and spatial nature of hydromorphological disturbance, turnover of species between sample locations at a range of scales, and the spatial arrangement of habitats and communities is of more use for detecting these types of subtle changes compared to mean richness or diversity. These findings have implications for the targeting of resources for monitoring of restoration, or engineering disturbances, in order to be sensitive to hydromorphological change. Efforts should target the main area of natural variability within the system, either replicating sampling in time or space to distinguish effects of impact. Spatial patterns, measures of beta diversity and species identity can be better exploited to identify systems with functioning geomorphological processes. Channel typologies proved misleading, and quantification of habitat and selection of control sites using multiple pre-defined criteria should be carried out. Studies of restoration operations and engineering impacts provide considerable opportunities for advancing our knowledge of the mechanisms that drive community response under a range of conditions to improve impact detection.

RESUMEN Los peces nativos son indicadores de la salud de los ecosistemas acuáticos, y se han convertido en un elemento de calidad clave para evaluar el estado ecológico de los ríos. La comprensión de los factores que afectan a las especies nativas de peces es importante para la gestión y conservación de los ecosistemas acuáticos. El objetivo general de esta tesis es analizar las relaciones entre variables biológicas y de hábitat (incluyendo la conectividad) a través de una variedad de escalas espaciales en los ríos Mediterráneos, con el desarrollo de herramientas de modelación para apoyar la toma de decisiones en la restauración de ríos. Esta tesis se compone de cuatro artículos. El primero tiene como objetivos modelar la relación entre un conjunto de variables ambientales y la riqueza de especies nativas (NFSR), y evaluar la eficacia de potenciales acciones de restauración para mejorar la NFSR en la cuenca del río Júcar. Para ello se aplicó un enfoque de modelación de red neuronal artificial (ANN), utilizando en la fase de entrenamiento el algoritmo Levenberg-Marquardt. Se aplicó el método de las derivadas parciales para determinar la importancia relativa de las variables ambientales. Según los resultados, el modelo de ANN combina variables que describen la calidad de ribera, la calidad del agua y el hábitat físico, y ayudó a identificar los principales factores que condicionan el patrón de distribución de la NFSR en los ríos Mediterráneos. En la segunda parte del estudio, el modelo fue utilizado para evaluar la eficacia de dos acciones de restauración en el río Júcar: la eliminación de dos azudes abandonados, con el consiguiente incremento de la proporción de corrientes. Estas simulaciones indican que la riqueza aumenta con el incremento de la longitud libre de barreras artificiales y la proporción del mesohabitat de corriente, y demostró la utilidad de las ANN como una poderosa herramienta para apoyar la toma de decisiones en el manejo y restauración ecológica de los ríos Mediterráneos. El segundo artículo tiene como objetivo determinar la importancia relativa de los dos principales factores que controlan la reducción de la riqueza de peces (NFSR), es decir, las interacciones entre las especies acuáticas, variables del hábitat (incluyendo la conectividad fluvial) y biológicas (incluidas las especies invasoras) en los ríos Júcar, Cabriel y Turia. Con este fin, tres modelos de ANN fueron analizados: el primero fue construido solamente con variables biológicas, el segundo se construyó únicamente con variables de hábitat y el tercero con la combinación de estos dos grupos de variables. Los resultados muestran que las variables de hábitat son los ¿drivers¿ más importantes para la distribución de NFSR, y demuestran la importancia ecológica de los modelos desarrollados. Los resultados de este estudio destacan la necesidad de proponer medidas de mitigación relacionadas con la mejora del hábitat (incluyendo la variabilidad de caudales en el río) como medida para conservar y restaurar los ríos Mediterráneos. El tercer artículo busca comparar la fiabilidad y relevancia ecológica de dos modelos predictivos de NFSR, basados en redes neuronales artificiales (ANN) y random forests (RF). La relevancia de las variables seleccionadas por cada modelo se evaluó a partir del conocimiento ecológico y apoyado por otras investigaciones. Los dos modelos fueron desarrollados utilizando validación cruzada k-fold y su desempeño fue evaluado a través de tres índices: el coeficiente de determinación (R2 ), el error cuadrático medio (MSE) y el coeficiente de determinación ajustado (R2 adj). Según los resultados, RF obtuvo el mejor desempeño en entrenamiento. Pero, el procedimiento de validación cruzada reveló que ambas técnicas generaron resultados similares (R2 = 68% para RF y R2 = 66% para ANN). La comparación de diferentes métodos de machine learning es muy útil para el análisis crítico de los resultados obtenidos a través de los modelos. El cuarto artículo tiene como objetivo evaluar la capacidad de las ANN para identificar los factores que afectan a la densidad y la presencia/ausencia de Luciobarbus guiraonis en la demarcación hidrográfica del Júcar. Se utilizó una red neuronal artificial multicapa de tipo feedforward (ANN) para representar relaciones no lineales entre descriptores de L. guiraonis con variables biológicas y de hábitat. El poder predictivo de los modelos se evaluó con base en el índice Kappa (k), la proporción de casos correctamente clasificados (CCI) y el área bajo la curva (AUC) característica operativa del receptor (ROC). La presencia/ausencia de L. guiraonis fue bien predicha por el modelo ANN (CCI = 87%, AUC = 0.85 y k = 0.66). La predicción de la densidad fue moderada (CCI = 62%, AUC = 0.71 y k = 0.43). Las variables más importantes que describen la presencia/ausencia fueron: radiación solar, área de drenaje y la proporción de especies exóticas de peces con un peso relativo del 27.8%, 24.53% y 13.60% respectivamente. En el modelo de densidad, las variables más importantes fueron el coeficiente de variación de los caudales medios anuales con una importancia relativa del 50.5% y la proporción de especies exóticas de peces con el 24.4%. Los modelos proporcionan información importante acerca de la relación de L. guiraonis con variables bióticas y de hábitat, este nuevo conocimiento podría utilizarse para apoyar futuros estudios y para contribuir en la toma de decisiones para la conservación y manejo de especies en los en los ríos Júcar, Cabriel y Turia.
Olaya Marín, EJ. (2013). Ecological models at fish community and species level to support effective river restoration [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/28853
TESIS

Abstract Streams and rivers have been extensively altered by humans. Channelization and land use have changed stream habitats and water quality with adverse effects on biota and ecosystem functions. Impacted streams have been targets for restoration, but there is considerable lack of understanding how streams should be restored in an ecologically effective way. In this doctoral thesis, I studied the impacts of channelization (for timber floating) and agricultural diffuse pollution on stream biota. I also studied the effectiveness of restorations of forestry impacted streams stressed by excessive sand sedimentation from catchment drainage. Finally, I also studied the effects of mosses, fine sediment and enhanced dispersal on stream macroinvertebrate communities and ecosystem functions. I found that channelization did not have effect on diatom, macrophyte, macroinvertebrate and fish assemblages, whereas diffuse pollution had strong effects, with no interactions between the two stressors. I showed that excessive sedimentation from forest drainage was harmful for stream biota but had no effect on leaf decomposition and algal accrual rate. Restoration with boulders reduced sand cover and was more beneficial for in-stream biodiversity, whereas restoration with wood tended to increase hydrological retention of stream channels, thereby altering riparian plant assemblages toward more natural composition. In a mesocosm experiment, I found mosses to have a strong impact on macroinvertebrate communities and ecosystem functions. Mosses increased organic matter retention and reduced algal accrual rate and leaf decomposition. The effect of mosses on macroinvertebrates was stronger than that of sand sedimentation, and mosses mitigated some of the negative effects of sand. Extensive dispersal had a distinct imprint on invertebrate community composition but did not blur the effect of mosses and sand on communities, suggesting strong local-scale environmental control of composition. My thesis emphasizes that priority in stream restoration should be in the mitigation of diffuse pollution rather than restoration of channel morphology, especially in streams where channel alteration has been fairly modest, as in the case of timber floating. Addition of both boulders and large wood likely yields the best biodiversity response in the restoration of forestry impacted streams. Mosses are a key component of boreal lotic ecosystems; therefore, the recovery of mosses may be a prerequisite for the full recovery of biodiversity and ecosystem integrity of boreal streams
Tiivistelmä Ihmisen toiminta on laajasti muokannut virtavesiä. Uomien kanavointi ja maankäyttö ovat muuttaneet virtavesien elinympäristöjä ja veden laatua, millä on ollut haitallisia vaikutuksia virtavesien luonnon monimuotoisuuteen ja ekosysteemin toimintaan. Huonokuntoisia virtavesiä on kunnostettu paljon, mutta ymmärrys siitä, kuinka virtavesiä tulisi kunnostaa parhaan ekologisen lopputuloksen saavuttamiseksi, on edelleen vajaata. Tutkin tässä väitöskirjassa uittoperkausten ja maatalouden hajakuormituksen merkitystä ja yhteisvaikutusta virtavesien eliöyhteisöihin. Tutkin myös kunnostusten vaikutusta hiekasta kärsivissä metsätalouden muokkaamissa puroissa, sekä vesisammalten, hiekan ja eliöiden levittäytymisen merkitystä purojen pohjaeläinyhteisöjen ja ekosysteemin toimintojen muovautumisessa. Havaitsin, että uoman perkauksilla ei ollut vaikutusta virtavesien eliöyhteisöihin, mutta hajakuormituksen vaikutus oli voimakas. Perkauksella ja hajakuormituksella ei ollut yhteisvaikutuksia eliöyhteisöihin. Osoitin, että metsäojituksista aiheutuva ylimääräinen hiekan sedimentaatio on haitallista virtavesien eliöille, mutta sillä ei ollut vaikutusta lehtikarikkeen hajotukseen tai päällyslevien tuotantoon. Kunnostukset joissa käytettiin kiveä vähensivät hiekan peittävyyttä ja olivat hyödyllisempiä uoman eliöstölle kuin kunnostukset, joissa tehtiin puurakennelmia. Puukunnostukset kuitenkin lisäsivät uoman vedenpidätyskykyä ja siten muokkasivat rantavyöhykkeen kasvillisuutta luonnontilaisemmaksi. Havaitsin, että vesisammalilla on voimakas vaikutus pohjaeläinyhteisöjen koostumukseen. Sammalet vaikuttivat ekosysteemin toimintoihin lisäämällä eloperäisen aineksen pidättymistä ja vähentämällä lehtikarikkeen hajotusta ja päällyslevien tuotantoa. Sammalten vaikutus pohjaeläimiin oli voimakkaampi kuin hiekan, ja sammalet kykenivät jopa lieventämään joitakin hiekan negatiivisia vaikutuksia. Eliöiden levittäytymisellä oli selvä vaikutus yhteisöjen koostumukseen, mutta se ei hävittänyt hiekan ja sammalen vaikutusta, mikä viittaa korkeaan ympäristötekijöiden merkitykseen yhteisöjen rakentumisessa. Tutkielmani korostaa, että maatalousjokien tilan parantamisessa hajakuormituksen hallinta tulisi olla ensisijainen kunnostustavoite uoman rakenteen kunnostamisen sijaan. Metsätalouden vaikutuksista kärsivissä puroissa kivi- ja puumateriaalin käyttö samanaikaisesti tuottaa luultavimmin laajimman vaikutuksen purojen monimuotoisuuteen. Sammalilla on merkittävä vaikutus muiden eliöiden yhteisökoostumukseen ja ekosysteemin toimintoihin, joten sammalten palautuminen on tärkeä kunnostustavoite virtavesissä, joissa on luonnostaan paljon sammalkasvustoa

Climate change and human activities alter the hydrologic systems and exerted global scale impacts on our environment with significant implications for water resources. Climate change can be characterized by the change of precipitation and temperature, and both precipitation pattern change and global warming are associated with the increase in frequency of flooding or drought and low flows. With increasing water demand from domestic, agricultural, commercial, and industrial sectors, humans are increasingly becoming a significant component of the hydrologic cycle. Human activities have transformed hydrologic processes at spatial scales ranging from local to global. Human activities affecting watershed hydrology include land use change, dam construction and reservoir operation, groundwater pumping, surface water withdrawal, irrigation, return flow, and others. In this thesis, the hydromorphology (i.e., the change of coupled hydrologic and human systems) of the Econlockhatchee River (Econ River for short) is studied. Due to the growth of the Orlando metropolitan area the Econ basin has been substantially urbanized with drastic change of the land cover. The land use / land cover change from 1940s to 2000s has been quantified by compiling existing land cover data and digitizing aerial photography images. Rainfall data have been analyzed to determine the extent that climate change has affected the river flow compared to land use change. The changes in stream flow at the annual scale and low flows are analyzed. The Econ River has experienced minimal changes in the amount of annual streamflow but significant changes to the amount of low flows. These changes are due to urbanization and other human interferences.
M.S.
Masters
Civil, Environmental and Construction Engineering
Engineering and Computer Science
Civil Engineering; Water Resources Engineering Track

The fluvial morphology of a river channel is a function of the river’s hydrologic and sediment regime. Within-channel river benches are a fluvial feature widely identified in the international literature as geomorphically and ecologically important. Despite this recognition the relationship between bench morphology and the flow regime is poorly understood. The aim of this thesis is to identify the components of the flow regime responsible for the formation and destruction of within-channel benches.
Opinions on the formative flows for benches are highly varied with reports that benches are formed by flows which just inundate the bench; to low-flow periods and sub-bankfull flows; bankfull flows and the annual flood; and moderate, medium and catastrophic sized floods. A large body of research also treats benches as a static morphology. Opinions on destructive flows are similarly varied. There is little empirical evidence for these suggestions.
A bench is most commonly referred to as comprising a horizontal (planar) surface which results from within-channel deposition, but the term is also used to describe bars, floodplains and erosional features. The inability of researchers to agree on the relationships between bench morphology and river hydrology is influenced by the lack of a consistent definition and classification for benches. To adequately address the aim this thesis is presented in two parts: Part A addresses bench nomenclature and provides a sound basis for Part B which addresses the processes of bench formation and destruction. (for complete abstract open document)

Dissertação de Mestrado Integrado em Engenharia do Ambiente apresentada à Faculdade de Ciências e Tecnologia
Currently, over half of the global population lives on urban areas, and this number is expected to continue growing. Urbanisation brings several environmental issues, water management being one of them, particularly stormwater management. The alteration of urban hydrology such as the increase of flashiness and runoff volume affects urban freshwater ecosystems, particularly urban streams. This dissertation highlights the importance of urban streams for achieving sustainable urban water management, since they are blue-green nature-based-solutions that provide several important ecosystem services to the urban population. Such services include, amongst others, the diminishing of flood risk, temperature regulation, and human wellbeing improvement. These benefits will contribute to achieving urban sustainability and improve the resilience of cities in face of urban growth and climate change.Considering how the ecology of urban streams is compromised due to urbanisation, the restoration of such systems is imperative. A review paper is introduced regarding urban stream restoration, namely why some restoration projects fail and how to successfully carry out such efforts. The communities of benthic macroinvertebrates expose the ecological state of a stream ecosystem, and thus implementing measures that improve the diversity of such assemblages will inherently improve the overall ecosystem and consequently, its function and ecosystem services. Essentially, to guarantee the success of urban stream restoration projects, the whole ecological context of the urban stream system needs to be assessed, including biologic interactions, morphology, hydrology, state of the watershed, water quality, sources of pollution, and land use. Once the context of the project is thoroughly understood, actions need to be prioritised according to the needs of the ecosystems.
Atualmente, mais de metade da população global vive em zonas urbanas, prevendo-se que este número continue a crescer. A urbanização traz vários desafios ambientais, sendo a gestão da água uma delas, particularmente a gestão da drenagem urbana. A alteração da hidrologia urbana (como o aumento do volume de escoamento superficial e diminuição do tempo de resposta) afeta os ecossistemas urbanos de água doce, particularmente os ribeiros urbanos. Esta dissertação sublinha a importância dos ribeiros urbanos para alcançar a sustentabilidade da gestão de água urbana, uma vez que se tratam de soluções azul-verdes, baseadas na natureza, que fornecem vários serviços de ecossistema importantes à população urbana. Estes serviços incluem, entre outros, a redução do risco de cheias, a regulação da temperatura do ar, e a melhoria do bem-estar dos residentes urbanos. Estes benefícios contribuirão para alcançar a sustentabilidade urbana e melhorar a resiliência das cidades face ao crescimento urbano e às alterações climáticas.Tendo em conta que a ecologia dos ribeiros urbanos está comprometida devido à urbanização, a restauração destes sistemas é imperativa. Apresenta-se um artigo de revisão abordando a restauração de ribeiros urbanos, nomeadamente a razão pela qual alguns projetos de restauração falham, e como garantir o sucesso de tais esforços. As comunidades de macroinvertebrados bentónicos revelam o estado ecológico de um ecossistema fluvial, e portanto, medidas que melhorem a diversidade destes conjuntos irão, inerentemente, melhorar o ecossistema global e, consequentemente, a sua função e serviços de ecossistema. Essencialmente, para garantir o sucesso dos projetos de restauração de ribeiros urbanos, todo o contexto ecológico do sistema de ribeiros deve ser avaliado, incluindo interações biológicas, a morfologia, hidrologia, estado da bacia urbana, qualidade da água, fontes de poluição, e utilização do território. Considerando o enquadramento do projeto, as medidas de restauração devem ser priorizadas de acordo com as necessidades dos ecossistemas.

Rivers are an integral part of the earth’s ecological, hydrological and physical systems, and also provide an indispensible range of services to humans. However, despite our strong dependence on rivers, human activities, and particularly the increased pressure on water resources, have resulted in a general degradation of river health world-wide. The long-term sustainability of many river systems is dependent on their successful management, and a key component of river management is to simply and meaningfully order streams into natural or arbitrary groups based on common characteristics. Such classification can assist in the management of rivers by increasing understanding of river form and process amongst the general complexity found in rivers. River classification has been central to developing an understanding of the links between hydrology, geomorphology and ecology and also allows knowledge from a particular river type at one location to be extrapolated to other locations of the same type, thus reducing resourcing requirements. Although possessing a relative abundance of water in comparison to many other regions, north-eastern Tasmanian faces pressures on water resources similar to those experienced elsewhere. In recent years, considerable effort has been directed towards achieving a balance between abstraction and environmental flows in north-eastern Tasmanian rivers, but this process has been complicated by the wide variety of riverine environments and channel and floodplain forms found in the region, and by the relatively few studies that have investigated the region’s geomorphology, hydrology, and ecology. Two approaches to classification have been adopted in the management of Tasmanian rivers. A nested hierarchical river classification system has been developed for Tasmania, and has formed the basis of a comprehensive river health assessment methodology. However this approach is relatively resource intensive, requiring data to be collected and expert analysis to be applied at different scales. In addition the large number of groups (river types) that this model produces means that developing relationships between flow alteration and physical and ecological response for each river type is impractical. A second approach has been the development of a broad two-classed model that classifies rivers on the basis of hydrological variability. Although this is an objective and quantitative model requiring few resources, the wide variety of river types included within each of the two classes mean that only the most generalised models linking hydrology, geomorphology and ecology can be developed. While each of these classification systems could be considered to fulfil the purpose for which they were designed, the lack of a simple and objective method to classify rivers into a reasonable number of meaningful classes on the basis of channel morphology has limited the development of predictive ecosystem models to link the physical and ecological responses of north-eastern Tasmanian rivers to altered flows. The aim of this study was to develop an objective and quantitative method to group north-eastern Tasmanian rivers and streams into hydromorphologically meaningful groups. This was achieved through several sub-studies; estimation of the magnitude and frequency of small floods, investigation of bankfull channel morphometry, analysis of the first order estimates of peak discharge of small floods, and assessment of the hydromorphological characteristics of different river basins. The magnitude-frequency of small floods (average recurrence interval < 5 years) was estimated by analysis of data from 13 north-eastern Tasmanian stream-gauging stations. Empirical comparisons were made between flood frequency estimates based on the annual series data set, those based on the partial series, and the Langbein method of converting annual series average recurrence intervals to partial series intervals. Annual series estimates were found to be one third the magnitude of partial series estimates at low average recurrence intervals, but converged with partial series estimates at around 5 years. The methods developed in this chapter are used in a later sub-study to develop relationships between discharge and catchment area for north-eastern Tasmanian Rivers. Two quantitative methods for determining bankfull stage from plotted channel cross-sections, the minimum width-to-depth ratio and the first maximum of the bench-index were evaluated against qualitative estimates of bankfull stage on 89 cross-sectional surveys undertaken at nine river reaches in north-eastern Tasmania. Results indicated that while neither method offered a suitable stand-alone means for estimating bankfull stage, they may in combination provide a means to approximate the range of bankfull stage and serve as a useful adjunct to other methods. The results also highlight the large variability in channel morphology along a reach. The results from this sub-study were used to assist in the identification of bankfull channel morphology parameters in a later assessment of hydromorphological characteristics of rivers and development of groupings. First order estimates of the peak discharge of small floods at ungauged sites in north-eastern Tasmania were investigated through the development of power-law equations relating the peak discharge of floods with average recurrence intervals ranging from 1.1 to 10 years to catchment area (Ad). Using data from 13 stream gauging stations, the analysis suggested that the discharge associated with a flood with two year average recurrence interval was estimated by Ad0.9. Intra-regional variation in the relationship was investigated and differences were found between those rivers which drain to the north coast and those which drain internally or to the east coast. The uncertainty and error associated with the study was also identified and discussed. Intra-regional variation in the relationship between discharge and catchment area identified a group of northward draining rivers in north-eastern Tasmania that plotted as negative residuals and a group of internally draining sites which plotted as positive residuals. Three hydromorphological characteristics of north-eastern Tasmanian rivers, drainage density, bankfull frequency and stream-power, were investigated using the results from the first order estimates of peak discharge of small floods sub-study. The range and variation in drainage density values was examined and found to broadly reflect variations in precipitation, elevation and geology. Variation in drainage density was found to be correlated to changes in the density of higher order streams, with little variation occurring in the density of first and second order streams. The range and variation in drainage density values was examined and found to broadly reflect variation in precipitation, elevation and geology. The two groups of rivers identified previously were found to have different drainage density ranges. Catchments draining northwards or eastwards to the coast were found to have drainage densities > 2 km km-1, while internally draining catchments were found to have drainage density < 2 km km-1. The estimation of bankfull discharge in north-eastern Tasmanian rivers was investigated, and peak discharge with an average recurrence interval of two years was proposed as a proxy for bankfull discharge. Attempts to accurately measure bankfull discharge at the study sites using field techniques were unsuccessful, as was the use of commonly used flow resistance equations. Large variances were found between estimates from different flow resistance equations, particularly at sites with deeper channels and high hydraulic radius. Estimates of peak discharge of small floods developed previously were used to develop suitable methods to estimate stream-power values. Substantial variability in downstream trends in stream-power was found in the Pipers, Ringarooma and Scamander rivers. These rivers were found to have different longitudinal trends and to deviate from the general downstream stream power trends found elsewhere. There was some evidence of an association between channel morphology and stream power, with high WD values/ low R values occurring at locations with high stream power. The river and catchment metrics developed in earlier chapters were then used in conjunction with univariate and multivariate statistical analysis in an attempt to develop meaningful hydromorphological groupings of north-eastern Tasmanian rivers. using objective and quantitative methods. A range of univariate and multivariate statistical techniques was applied to a dataset consisting of 164 channel cross-sections from thirteen sites, and the results were assessed against a separate dataset containing 58 cross-sections from 15 sites. A strong source of underlying variability in the channel morphdataset was found to occur along an orthogonal axis which had high values of width-to-depth ratio at one end and high hydraulic radius values at the other. The variability of bankfull channel morphology both along a reach and between sites was examined, and Principal Components Analysis and agglomerative clustering used to examine the underlying structure in the data and identify the best low-dimensional representation of the variability in channel morphology. The river and catchment metrics developed in earlier chapters were then used in conjunction with multivariate statistical analysis of channel cross-sectional data from field surveys to investigate variability in channel morphology and develop a quantitative morphological typology. A strong source of underlying variability in the dataset was found to occur along an orthogonal axis which had high values of width-to-depth ratio at one end and high hydraulic radius values at the other. While analysis was able to identify two groupings with membership based on either high width-to-depth ratio or high hydraulic radius, methods to derive the groupings of sites based on channel parameters using remote parameters were generally unsuccessful; combinations of the remote parameter values were unable to reproduce natural grouping identified using channel parameters. However drainage density was identified as a strong remotely sensed predictor variable. The results suggest that localised and reach scale factors have more influence on channel morphology than catchment scale controls in north-eastern Tasmanian rivers. The overall study results suggest that north-eastern Tasmanian rivers are highly variable and have characteristics different from those found elsewhere. This has implications for the use of remotely sensed data and GIS tools in the study of regional hydromorphological characteristics.

The thesis is aimed on hydromorphological assessment with usage of distance data. The distance method QuaWaDis is defined and the usage of results of image processing within the hydromorphological assessment is considered. The aim of the assessment is classification of hydromorphological conditions of water bodies according to Water Framework Directive 2000/60/EC. Distance method is based on visual interpretation of public data. Image processing results can extend the number of parameters of the distance method - object based classification was applied on aerial imagery (in land cover classification), unsupervised classification and image reclassification was applied on multispectral satellite data (in water depths classification). The calibration of distance method and the credibility of the distance data was evaluated in comparison with results of field survey EcoRivHab (Matoušková, 2008). Object based image processing was aimed on accuracy assessment, index of efficiency was defined and the concept of fuzzy logic was applied in accuracy assessment. From consideration of classification efficiency is obvious, that large internally heterogeneous objecs is more effectivelly to vectorise manually. Accuracy assessment with usage of concept of fuzzy logic shows the success of object recognition within each...

Today, the study of fluvial-morphological processes is focused on evaluating hydromorfological status of streams and on proposing restoration measures. A fundamental prerequisite for assessing the current hydromorphological status of streams is establishing reference conditions for each stream type that serve as a benchmark and represent the target status after restoration. The aim of this thesis is to describe type-specific hydromorphological reference conditions for rivers on the territory of the Czech Republic with the help of determining river types, developing the REFCON method for establishing reference sites and recording characteristics of reference status. The approach to establishing reference sites is based on meeting the criteria of having minimal anthropogenic impact that are first assessed using cartographic data and subsequently verified through field survey. Parameters - altitude, sinuosity, and valley floor slope - for classifying river reaches into types were determined on the basis of the results of statistical methods applied on 3197 river reaches covering the whole territory of the Czech Republic. The classification of river reaches into 9 river types was verified through field survey at 44 sites. Detailed field survey and measurements of characteristics of natural channel...

This thesis deals with the retention capacity of Berounka during the hydrological extremes. Flood prevention and flood condition are main subjects of this thesis. Two selected river areas of Berounka are analysed by the passive retention volume and by the transformation of the flood wave. The first area is situated on the lower course of Berounka near the Černošice, and this area is significantly anthropogenically influenced. The second area which has nature character is located on the middle course of Berounka near Křivoklát. This thesis contains an evaluation of the hydromorphological state of flow in both areas. The results of passive retention indicate negligible influence of the flood situations. 1D hydraulic model HEC-RAS displays the transformation of the flood wave. The results of the transformation are flow velocity and depths of the river valley in 100-year-old and 20-year-old flows. The transformation of the flood wave in the first area is on the minimum level and did not reach its potential retention capability. The culmination flow in the second area is reduced because of a geomorphological shape of the river. Moreover, the near natural flood protection precautions are proposed in this thesis. Mean flow velocity in 100-year floods could be reduced by 1 - 1,6 m.s-1 by forestation of...

The thesis deals with the status assessment of the stream in urban areas. The study area is the stream Rokytka in Prague. The method Hydroecological monitoring HEM (Langhammer, 2007, 2013) was used for the thesis based on field hydromorphological survey. This method is compatible with the Water Framework Directive 2000/60/EC. The thesis also includes assessement of the rainoff regime and water quality based on the available hydrological and hydrochemical data. As a final result, it was found out the stream Rokytka achieves III. hydromophological state - average state. The water quality state does not meet the requirements of the environmental standards quality. In the urban landscape, it is necessary to find a suitable compromise between flood protection and good environmental conditions. Powered by TCPDF (www.tcpdf.org)