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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Century of Geomorphic Change of the San Rafael River and Implications for River Rehabilitation

Fortney, Stephen T. 01 August 2015 (has links)
Suspended-load rivers are subject to rapid geomorphic changes. In particular during the Holocene Epoch, arroyos of the Colorado Plateau experienced several periods of rapid erosion and aggradation. The most recent period of entrenchment occurred around the turn of the 20th century. The mechanisms responsible for the modern period of aggradation that has followed the most recent period of entrenchment have not been well documented. The research presented in this thesis reveals the mechanisms responsible for modern alluviation of the San Rafael River, which drains the Colorado Plateau The lower 87 km of the San Rafael River, which enters the Green River south of the town of Green River, UT has experienced rapid geomorphic changes during the last 100 years. To quantify these changes, we used a complement of temporally precise and spatially robust methods. By understanding the rates, magnitudes and types of geomorphic changes, we could then identify the mechanisms of these channel changes. The San Rafael River narrowed by 83% between 1938 and 2009 and the floodplain aggraded 1.0 to 2.5 m. Channel narrowing was caused by a reduction in the transport capacity of the river, and was accelerated by the establishment of vegetation, including the non-native tamarisk shrub, on active channel surfaces and the floodplain. Significant water withdrawals during the 20th century have primarily been responsible for the reduction in transport capacity by decreasing the magnitude and duration of the annual snowmelt flood. During this time period, monsoon floods continued to deliver large quantities of fine sediment to the channel. During the 20th century, the channel bed incised in one segment and aggraded in five segments. The two periods of incision that we documented were related to human modifications of the channel and floodplain. With the knowledge of the physical processes that have been responsible for the channel changes in the San Rafael River, prediction of future channel conditions can then be made. The changes to the physical template of the San Rafael River have implications for the management of three endemic fish – the roundtail chub (Gila robusta robusta), the bluehead sucker (Catostomus discobolus), and the flannelmouth sucker (Catostomus latipinnis) – which currently utilize the study area.
2

Effects of Urban River Rehabilitation Structures on the Fish Community of the Ottawa River, Ohio

Svoboda, Aaron Dennis January 2014 (has links)
No description available.
3

Sedimentation patterns and riparian vegetation characteristics in novel ecosystems on the Rhône River, France : A comparative approach to identify drivers and evaluate ecological potentials / Patrons de sédimentation et caractéristiques de la ripisylve dans les casiers Girardon du Rhône : approche comparative pour une analyse des facteurs de contrôle et une évaluation des potentialités écologiques

Räpple, Bianca 08 June 2018 (has links)
A l’image du Rhône au sud-est de la France, les fleuves font l’objet de multiples usages, entrainant des modifications profondes de leurs dynamiques fluviales. Par conséquent, les fonctionnements hydro-sédimentaire et écologique de leurs chenaux ainsi que de leurs plaines alluviales sont altérés. Des programmes intégrés de restauration s’attellent à définir les potentiels et les risques liés à de tels ‘écosystèmes anthropo-construits’ et de comprendre les interactions entre divers facteurs de contrôle ayant influencé leur formation. La présente étude s’est focalisée sur 293 casiers Girardon – des unités rectangulaires délimitées par des digues submersibles longitudinales et latérales construites dans le lit mineur au 19ème siècle afin d’améliorer la navigabilité du Rhône. Ceux-ci sont distribués sur quatre secteurs court-circuités au 20ième siècle pour la production hydro-électrique. Nous avons analysé les patrons spatio-temporels de la sédimentation, ainsi que la structure et la composition des boisements grâce à des données issues de la télédétection et de terrain. Nous proposons également un modèle conceptuel des facteurs de contrôle et des processus potentiels en lien avec les patrons observés. Quatre-vingts pourcents des casiers ont évolué du stade aquatique à un stade terrestre et boisé, suivant des trajectoires historiques variées à la fois inter- et intra-secteurs. Les boisements diffèrent en caractéristiques structurelles de boisements de référence plus naturels. Leur composition est plus proche de celle des systèmes matures que pionniers. Nous observons également une forte présence d’espèces allochtones, comme par exemple l’Érable negundo (Acer negundo), invasive, en particulier dans les stades de régénération. Notre approche comparative constitue une première étape pour démêler les effets cumulatifs des facteurs de contrôle et hiérarchiser leurs rôles individuels. Nous avons constaté que des facteurs locaux jouent un rôle majeur, en particulier la connectivité au chenal principal court-circuité. L’évolution des facteurs environnementaux eux-mêmes a contribué à la complexité des patrons. Ce travail ouvre la voie à des futures études sur des écosystèmes anthropo-construits sur cours d’eau, et donne une nouvelle perspective aux gestionnaires du Rhône relativement à son échelle spatiale innovante. / The multiple uses made of large rivers, such as the Rhône in south-eastern France, have provoked profound modifications of their fluvial dynamics. As a consequence, the hydro-sedimentary and ecological functioning of their channels and floodplains are highly altered. Integrated restoration programmes struggle in defining potentials and risks related to such ‘novel ecosystems’ and to understand the various interacting drivers which influence their formation. This study comparatively focused on 293 dike fields—rectangular units delimited by longitudinal and lateral submersible dikes constructed in the channel in the late 19th century to promote the navigability of the Rhône. They are distributed over four reaches by-passed in the 20th century for hydro-electric energy production. We investigated the spatio-temporal patterns of sediment deposition and the structure and composition of the forest stands using remote sensing and field data. We also propose a conceptual model of potential drivers and processes behind the observed patterns. Eighty percent of the dike fields have evolved from the aquatic to a terrestrial and forested stage, following variable historical trajectories both between and within reaches. The forest stands presented structural characteristics which differed from more natural reference stands and compositional characteristics closer to mature than to pioneer systems. They featured a high presence of non-native species, such as the invasive Box elder (Acer negundo). Our comparative approach constituted a first step to disentangle the cumulative effects of the drivers and define their individual roles: we discovered a prominent role of local factors, especially the connectivity to the main by-passed channel. The evolution of the environmental factors themselves added to the complexity of the patterns. This work provides a basis for future studies of novel ecosystems on rivers, and a new perspective to river managers on the Rhône due to its innovative spatial-scale.
4

Ambientes fluviais urbanos: novos paradigmas de projeto / Urban water environment intervention: new design paradigms

Cardoso, Francisco Jos? 07 February 2017 (has links)
Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2017-03-23T13:43:04Z No. of bitstreams: 1 FRANCISCO JOS? CARDOSO.pdf: 18250716 bytes, checksum: 3d4c82c599397b6cafcc66385555685d (MD5) / Made available in DSpace on 2017-03-23T13:43:04Z (GMT). No. of bitstreams: 1 FRANCISCO JOS? CARDOSO.pdf: 18250716 bytes, checksum: 3d4c82c599397b6cafcc66385555685d (MD5) Previous issue date: 2017-02-07 / Water environments are spaces that present ecological-functional importance for the maintenance of given biodiversity. Nonetheless, in the history of cities, its physicalenvironmental decharactation is recurrent, specially by the adoption of solutions focusing hydrosanitarism which do not take into consideration the relations between the environmental and urban dynamics. The structural contradictions of the contemporary urbanization process intensify the problems and the challenges to be overcome. The contemporary interventions studied show a tendency to rethink the techno-scientific model adopting new ecological-environmental paradigms, developed in accordance to the specificities of its environmental and urban context. As a contributing result of the research, recommendations for the elaboration of projects in a dialogical and systemic ways are presented. First of all, the aspects related to the environmental dynamics and the transformations resulting from the process of urbanization are approached, highlighting inadequate interventions that drive the population away from the physical, social and cultural relationship with urban waterways and the new perspectives which embody such watershed as structural element. Following, the background of urbanism with environmental-ecological concerns is exposed, its strands and a survey of national and international experiences of projects carried out in water environments, as well as the reflection on the new paradigms of urbanism with an ecological-environmental preoccupation. 150 projects in 24 countries, were surveyed and analyzed, due to the interventions value water within urban environments. From these, three projects were selected and analyzed in detail, using an specific methodology that seeks to establish a systemic and dialogical reading. In the last part of the thesis, recommendations in relation to methodological aspects and solutions to intervention projects that promote the incorporation and valorization of the water environment elements in the morphology and the urban landscape are presented, taking into consideration the relations between the environmental and urban dynamics. It was concluded that the projects of intervention in urban water environments must establish the dialectic among the environmental, urban and human dimension, having as an assumption that mankind does not create new systems, that the city has its own rationality and that the urban water environments are spaces with multiple functions. Its design must come from the comprehension of the environmental and urban dynamics, establishing principles and criteria coherent to this reality, which consider the multiple dimensional and scaled relations, featuring multiple objectives to respond to the complexity of the urban environment. The intervention should contemplate and/or articulate the scales of the regional and urban planning with punctual interventions in the water environment. The differential, which qualifies the intervention in urban water environments, is the valorization of the water as an aesthetic element and its incorporation as element of the morphology and of the urban landscape, from the comprehension of its watershed and of the relation of larger and smaller scales. / Os ambientes fluviais s?o espa?os que apresentam intera??es ecol?gico-funcionais importantes para a manuten??o da biodiversidade. Por?m, na hist?ria das cidades ? recorrente a sua descaracteriza??o fisco-ambiental, principalmente, pela ado??o de solu??es com enfoque hidrossanit?rio que n?o levam em considera??o as rela??es entre a din?mica ambiental e urbana. As contradi??es estruturais do processo de urbaniza??o contempor?nea intensificam os problemas e os desafios a serem enfrentados. As interven??es contempor?neas estudadas demonstram a tend?ncia de repensar o modelo t?cnico-cientifico, adotando novos paradigmas ecol?gico-ambientais, desenvolvidos de acordo com as especificidades do seu contexto ambiental e urbano. Como contribui??o resultante da pesquisa s?o apresentadas recomenda??es para elabora??o de projetos de forma dial?gica e sist?mica. Primeiramente, s?o abordados os aspectos relacionados com a din?mica ambiental e as transforma??es decorrentes do processo de urbaniza??o, com destaque para as interven??es inadequadas que levam a popula??o ao afastamento f?sico, social e cultural em rela??o aos cursos d??guas urbanos e ?s novas perspectivas que incorporam a bacia hidrogr?fica como elemento estruturante. A seguir s?o expostos os antecedentes do urbanismo com preocupa??o ecol?gico-ambiental, suas vertentes e o levantamento das experi?ncias nacionais e internacionais de interven??es em ambientes fluviais, assim como a reflex?o sobre os novos paradigmas do urbanismo com preocupa??o ecol?gico-ambiental. Foram levantados e analisados aspectos gerais em rela??o a concep??o de 150 projetos, em 24 pa?ses, com interven??es que valorizam a ?gua no meio urbano. Os projetos desenvolvidos para as cidades de Velenje (Eslovenia), Denver (Estados Unidos) e Belo Horizonte (Brasil) foram selecionados e analisados detalhadamente, a partir de uma metodologia pr?pria que procura estabelecer uma leitura sist?mica e dial?gica. Na parte final do trabalho s?o apresentadas recomenda??es em rela??o aos aspectos metodol?gicos e solu??es de projetos de interven??o que promovam a incorpora??o e valoriza??o dos elementos do ambiente fluvial na morfologia e na paisagem urbana, levando-se em considera??o as rela??es entre a din?mica ambiental e urbana. Conclui-se que os projetos de interven??o em ambientes fluviais urbanos devem estabelecer a dial?tica entre a dimens?o ambiental, urbana e humana, tendo como pressupostos que o homem n?o cria novos sistemas, que a cidade possui uma racionalidade pr?pria e que os ambientes fluviais urbanos s?o espa?os com m?ltiplas fun??es. Sua elabora??o deve partir da compreens?o da din?mica ambiental e urbana, estabelecendo princ?pios e crit?rios coerentes com essa realidade, que levem em considera??o as m?ltiplas rela??es dimensionais e escalares, apresentando m?ltiplos objetivos para responder ? complexidade do meio urbano. A interven??o deve contemplar e/ou articular as escalas do planejamento regional e urbano com as interven??es pontuais no ambiente fluvial. O diferencial, que qualifica os projetos de interven??o em ambientes fluviais urbanos, est? na valoriza??o da ?gua como elemento est?tico e a sua incorpora??o como elemento da morfologia e da paisagem urbana, a partir da compreens?o da sua bacia hidrogr?fica e da rela??o com escalas maiores e menores.
5

An Approach To Urban River Rehabilitation For Coexistence Of River And Its Respective City: Porsuk River Case And City Of Eskisehir

Simsek, Gul 01 July 2011 (has links) (PDF)
All living things mostly the humans, as builders of civilizations, have always been in intrinsic bonds with water. This interaction between water (oceans, seas, lakes, rivers etc.) and settlements has existed since ancient civilizations. Among water resources, &lsquo / flowing waters&rsquo / such as rivers, streams, creeks, etc. have a prominent role as they are the lifeblood of most cities in terms of providing transportation, security, energy, irrigation, commerce, and recreation. By the late 19th century, developments of terrestrial transportation modes diminished the magnetism of rivers and riverfronts, and growing industries led to the deterioration of rivers. Owing to these reasons, along with many others, they turned into sewage channels, were covered up, and became water scopes detached from the urban life. Particularly since the 1970s, with more attention given to sustainability of resources, a greater awareness has grown of the vital role of urban rivers as a resource for humans and a lifeline for cities. After being neglected for decades, urban rivers have started to be rehabilitated to solve the related problems. The new approach to urban river rehabilitation beyond classical practices that aim at recovering the physical conditions of rivers has come to the fore to address the problems comprehensively. Instead of independent and one-dimensional practices, the urban rivers have become to be seen as a vital part of urban water system and of the city itself. While rehabilitating urban rivers, recovering river health can be ensured provided that the entire urban water ecosystem is taken into consideration. The ecocity approach is one of the major new approaches that geared toward achieving a healthy city, and sustainability of water system is the significant goal within this approach. In this regard, the thesis first asserts that the ecocity criteria are likely to give way to a more sustainable future for urban rivers. Besides being a part of the ecosystem, urban rivers have transformed together with the surrounding built environment throughout the history of cities. Significant focal elements of the urban pattern, urban rivers should be dealt with other urban focal points, with the introduced concept of river-city integration, which is proposed as the second assertion of the thesis. In this respect, the study attempts to investigate urban rivers and their rehabilitation in relation with both the ecocity approach, and the river-city integration concept. The research methodology in the present study involves comparative anaysis of best practices and case study analysis. Porsuk River and the city of Eskisehir, which the river passes through, were selected as a case for empirical study. Criteria sets that determined within the frames of ecocity and river-city integration, and the testing of the criteria in the case area offers an opportunity to contribute to literature of river and city coexistence.
6

Brněnské nábřeží - rehabilitace brněnských řek a jejich blízkého okolí / Brno waterfront - rehabilitation of rivers and their surrounding areas

Vrána, Adam January 2017 (has links)
The aim of the assignment was to rehabilitate the area of the Brno embankment of the river Svitava and the nearby surroundings of the river. This is the modification of the river's seashore, the modification of public spaces and the completion of individual objects. The solved territory is defined in the east and north of Cejl streets, on the east of the Svitava river and on the south by Tkalcovska street. The principles of the proposal are based on the necessary changes to the territory. The biggest problem of the area is the area backups for the hypermarket parking lot and the urbanistically incoherent structure of the courtyards and the poorly functioning waterfront. The proposal focuses on making the river accessible and bringing water closer to people. On the waterfront the bicycle path is used not only by cyclists. The former hypermarket is converted into a shopping mall and the ground floor of the seafront is made up of shops, services, cafes and restaurants. For humans, a river was available that could touch water. For relaxation and recreation, the terraces are provided. Better permeability also offers the river itself. By modifying the footbridge and delivering a new footbridge in the middle part, pedicists and cyclists can better cross the river. The park and the reclamation of planted trees have been modified. The Svitavy Drive in the section of the park was also accessible by foot. The siding was preserved to a certain extent in order to be able to prepare a wagon with a café or other possibilities of the Svitava festival under the steam. The construction of new houses increases the attractiveness of the area itself and offers both flats overlooking the river with the dominant of the church as well as services in the workshops of the individual houses. Cejl street has a green and a plumbing and a missing pit. Transparency for people is from the weft loom on the waterfront through the park, business or residential street.Residential homes have ma
7

Urbanistické řešení nábřeží řeky Jihlavy v Třebíči / Urban design of waterfront in Třebíč

Vacek, Jiří January 2014 (has links)
Thesis is concerning urbanistic treatment of Jihlava river embankment in the city of Třebíč. Tries to find cause for urban non-functionality of the area within local and wider context to its surroundings. Offers possible solution for rehabilitation of the urbanistic function of the embankment, including putting the embankment into role of important passageway, improving its bounds to the surroundings and active role in city's everyday life.
8

Large rivers’ fish assemblages under multiple pressures

Zajicek, Petr 18 April 2019 (has links)
Europäische große Flüsse wurden über Jahrhunderte entscheidend verändert und zu Wasserstraßen für die Schifffahrt ausgebaut. Flussregulierung, Begradigung und Hochwasserschutz tragen zu multiplen Stressoren bei, wobei die Schifffahrt bislang keine Beachtung als potentieller zusätzlicher Einflussfaktor (Stressor) fand. Die zentrale Fragestellung dieser Arbeit befasste sich mit der Rolle der Schifffahrt zwischen multiplen Stressoren und deren Auswirkungen auf die Fischgemeinschaften großer Flüsse. Hierzu wurde die „Large River Fish Database“ (LRDB), ein weltweit einzigartiger Datensatz zusammengestellt, der 2693 Befischungen an 358 Probestellen in 16 europäischen großen Flüssen enthält. Die Probestellen sind durch verschiedene Einflussfaktoren (Stressoren) und Schiffsverkehr beschrieben. Um ein für große Flüsse repräsentatives Abbild der Fischgemeinschaften zu erhalten, wurden zunächst die angewendeten Fischfangmethoden analysiert. Mit der Elektrofischerei wurden die höchsten Fischdichten und die höchste Biodiversität erfasst. Die Elektrofischerei ist daher für eine repräsentative Erfassung der Fischgemeinschaften großer Flüsse geeignet und wurde für weitere Analysen ausgewählt. Die kommerzielle Frachtschifffahrt trat als einer der einflussreichsten Stressoren hervor, zusammen mit erhöhter Fließgeschwindigkeit und dem Verlust von Überschwemmungsflächen. Dichten von insbesondere Habitat-sensitiven Fischen sanken bereits ab acht Frachtschiffen pro Tag signifikant ab. Darüberhinaus hatte auch die Freizeitschifffahrt (Flusskreuzfahrten und motorisierte Sportboote) deutliche und zu Frachtschiffen unterscheidbare ökologische Konsequenzen. Die Wirkungen der Schifffahrt sind ebenso verheerend wie die der hydromorphologischen Degradierung und benötigen eine gesonderte Beachtung im Flussmanagement und der Flussrevitalisierung. Freizeitboote und Flussdampfer wirken der Flussrenaturierung kleinerer Wasserstraßen entgegen und gefährden den ökologischen Erfolg des Blauen Bandes. / European large rivers have been tremendously modified over centuries and transformed into waterways for inland navigation. Extensive river modifications such as river regulation, channel straightening and flood protection have resulted in multiple pressures. However, inland navigation has not been considered as a potential pressure yet. This thesis aimed to assess the role of inland navigation among the most prevailing pressures in large rivers under field conditions. A worldwide unique and complementary dataset, the Large River Fish Database (LRDB) was compiled. The LRDB consists of 2693 fish samples assessed at 358 sampling sites in 16 European large rivers. Sites were characterized by various pressure variables and frequencies of ship traffic. To derive representative samples of large rivers fish assemblages, performance of various fishing gears applied was assessed. Electrofishing samples represented highest densities of fish and highest overall biodiversity. Therefore, electrofishing is suitable for fish-based assessments of large rivers and only electrofishing samples were selected to assess multiple pressures and inland navigation. Commercial cargo navigation appeared as the most influential pressures on large rivers fish assemblages among increased velocities and the loss of floodplains. Starting at already eight passing vessels per day, densities of particularly habitat-sensitive spawners significantly declined. Moreover, recreational navigation such as river cruises and motorized sport boats had distinct ecological consequences to those of cargo vessels. Inland navigation is as detrimental as the hydromorphological degradation of the river channel and requires specific attention in river management and rehabilitation. Pleasure boating (river cruises and sport boats) will counteract river rehabilitation also in smaller waterways and delimit ecological success of the Blue Band initiative in Germany.

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