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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.
61

Apport de la géomatique pour une caractérisation physique multi-échelle des réseaux hydrographiques. Elaboration d'indicateurs appliqués au bassin du Rhône. / Contribution of geomatics for multiscale physical characterization of river systems Development of indicators applied to the Rhone basin

Wiederkehr, Elise 12 December 2012 (has links)
Selon la Directive Cadre européenne sur l’Eau (DCE), le bon état écologique de tous les milieux aquatiques devra être atteint d’ici 2015. Cet état s’évalue en grande partie au moyen de paramètres biologiques, eux-mêmes régis par les conditions physico-chimiques et hydromorphologiques des masses d’eau. Pour atteindre les objectifs de la DCE, l’évaluation de l’état physique du réseau hydrographique apparaît comme une phase essentielle alors que cette question relève encore pour certains aspects de la recherche fondamentale. La mise en oeuvre de cette étape à l’échelle du bassin du Rhône entraîne un certain nombre de questions scientifiques auxquelles il est nécessaire de répondre avant d’envisager toute application. En effet, les connaissances dans les domaines de la géomorphologie ou de l’hydrologie sont aujourd’hui suffisantes à l’échelle locale pour envisager de régionaliser ce type d’informations. Cependant le changement d’échelle est à l’origine de contraintes méthodologiques importantes liées notamment à la très grande hétérogénéité des milieux à caractériser.L'objectif de cette thèse est donc double. D’une part, il s’agit de mettre en place des outils géomatiques permettant d’obtenir une vision globale et homogène des caractéristiques physiques du réseau hydrographique. Pour cela, nous proposons (i) de développer une méthodologie d’extraction de l’information à partir de données vectorielles ou rasters, et (ii) de définir des indicateurs pertinents de caractérisation hydrogéomorphologique. D’autre part, ces outils et cette méthode ont été testés et appliqués sur le réseau hydrographique du Rhône afin d’évaluer leur efficacité et de proposer des éléments fiables de caractérisation des conditions physiques à large échelle. / According to the Water Framework Directive (WFD), the good ecological status of all aquatic environments should be achieved by 2015. This status is evaluated largely using biological parameters, which are controlled by the physico-chemical and hydromorphological conditions of water bodies. To achieve the objectives of the WFD, assessing the physical condition of the hydrographic network appears to be a prerequisite, yet this issue still requires research of a fundamental nature. This stage in the basin of the Rhône raises a number of scientific issues which it is necessary to answer before considering practical application. In fact, knowledge of geomorphology and hydrology is now sufficient at a local scale and we can envisage applying this information at a regional scale. However, the change of scale results in important methodological constraints linked in particular to the great heterogeneity of environments.This thesis has two objectives. The first one is to implement geomatic tools to obtain an overall and homogeneous characterisation of the physical network. We propose to develop a methodology to extract information. Second, these tools and methodology will be tested and applied to the Rhône River system to evaluate their effectiveness and to provide reliable evidence for the characterization of large-scale physical conditions.
62

Etat de la qualité des eaux de l’estuaire de la Gironde : cas du cadmium et des butylétains / Water quality assessment of the Gironde Estuary : case study of cadmium and butyltins

Pougnet, Frédérique 12 February 2018 (has links)
L’estuaire de la Gironde est affecté par une pollution polymétallique historique, dont la contamination persistante en cadmium (Cd) empêche une reprise complète et le développement de la conchyliculture girondine, avec un risque potentiel pour le 1er site ostréicole français (Marennes-Oléron). D’autre part, le suivi de l’état de la qualité chimique des masses d’eau, mis en place par la Directive Cadre sur l’Eau (DCE) a déclassé en 2009 la masse d’eau « Gironde centrale » à cause de niveaux élevés en tributylétain (TBT), hautement toxique et interdit depuis plusieurs décennies, détecté dans l’estuaire de la Gironde.Ce travail se base sur 12 campagnes océanographiques comprenant un suivi temporel mensuel pendant l’année 2015 aux sites de surveillance DCE (PK52 et PK86), à PK 30 et 3 profils longitudinaux sur l’ensemble du gradient salin depuis Bordeaux jusqu’à l’embouchure. Les mesures in-situ et les échantillons visaient à caractériser l’état actuel de la qualité des eaux girondines pour Cd et butyl-étains dans le contexte historique de décontamination et de résilience du système fluvio-estuarien. Les résultats ont montré les plus faibles additions en Cd dissous (Cdd) dans le gradient salin depuis 2002, pour des conditions hydriques contrastées. Le développement de plusieurs méthodes de calcul a permis de montrer une diminution des flux nets de Cdd au cours des 30 dernières années d’un facteur ~10. Les concentrations en Cd particulaire (Cdp) présentent des valeurs de l’ordre de 0,45 ± 0,07 mg/kg ces 10 dernières années. Cette valeur est supérieure au bruit de fond géochimique de l’estuaire salin (0,2 mg/kg) suggérant la persistance d’un potentiel de contamination de la zone côtière par désorption. Des mesures ADCP à l’embouchure de l’estuaire couplées à des analyses géochimiques ont permis d’estimer quantitativement les flux nets en matières en suspension (MES) et Cdp pour des conditions hydrologiques extrêmes. La prise en compte de l’ensemble de résultats scientifiques (mesures et modélisation hydrosédimentaire) antérieures et l’analyse des évènements de crue et des coefficients de marée depuis 1990 ont permis de proposer un modèle conceptuel d’export de MES et Cdp en zone côtière. Le suivi mensuel sur l’année 2015 montre que l’estuaire de la Gironde reste déclassé en TBT avec deux valeurs ponctuelles supérieures à la NQE-CMA et avec des moyennes annuelles supérieures à la NQE-MA pour les PK30, PK52 et PK86. Les enregistrements longitudinaux des butylétains (TBT, dibutylétain (DBT) et monobutylétain (MBT)) dans les compartiments eaux, MES et sédiments de l’ensemble de l’estuaire de la Gironde ont permis de mettre en évidence plusieurs sources potentielles actuelles localisées au niveau de Bordeaux, du Bec d’Ambès, mais surtout au niveau de la masse d’eau aval. / The Gironde Estuary is affected by historical multi-metal pollution. Persistent contamination by cadmium (Cd) prevents complete recovery of the Gironde oyster farming, and implies potential risks for the most important oyster farming areas in France (Marennes-Oléron). In addition, the water quality survey governed by the Water Framework Directive (WFD), has downgraded the "Central Gironde" water body in 2009 due to the presence of TBT, a highly toxic organo-metallic compound, on the list of priority substances and banned for several decades.This work relies on 12 oceanographic campaigns, including a monthly survey at the WFD monitoring sites (KP52 and KP86) in 2015 with additional sampling at KP30. Furthermore, 3 longitudinal profiles were carried out along the salinity gradient to characterize the current state of water quality in the Gironde Estuary for Cd and butyltin species, in a perspective of decontamination and resilience. The results showed the lowest dissolved Cd additions (Cdd) along the salinity gradient since 2002, for contrasting hydrological conditions. The development of several calculation methods has shown a decrease in net Cdd flows over the past 30 years by a factor of ~10. Particulate Cd (Cdp) concentrations were in the range of 0.45 ± 0.07 mg/kg during the past 10 years. This value is higher than the geochemical background of the saline Gironde Estuary (0.2 mg/kg) suggesting the persistence of potential contamination of the coastal zone by desorption. Physical and chemical measurements at the estuary mouth coupling ADCP with geochemical analyses have provided estimates of the suspended particulate matter (SPM) and Cdp fluxes, for extreme hydrological conditions. The set of previous scientific results (measurements and hydro-sedimentary modeling), the analysis of time-series of flood events and tidal coefficients since 1990, have been integrated into a conceptual model for the export of SPM and Cdp to the coastal zone. The 2015 monthly survey according to the WFD has produced two distinct values and annual average concentrations both exceeding the respective environmental quality thresholds showing that the Gironde Estuary remains downgraded with respect to TBT. Longitudinal records of butyltins (TBT, dibutyltin (DBT) and monobutyltin (MBT)) in water, SPM and sediment of the entire Gironde Estuary have pointed to several potential sources including urban discharges (from Bordeaux), industrial releases (Bec d’Ambès) and estuarine dredging activities (from downstream harbours).
63

Making water information relevant on local to global scale – the role of Information Systems for Integrated Water Management

Hannerz, Fredrik January 2008 (has links)
<p>Relevant information is essential for finding solutions in Integrated Water Management (IWM). Complex water systems and a need for increasing integration of sectors, actors and scales in IWM require new methods for developing and managing such information. This thesis investigates the role of information within the IWM process, as well as the main challenges for development of representative, accessibleand harmonized information. Results show how information needs and the information production process for IWM may be systematized, and indicate a large potential for information system development for IWM. However, in order to reach the full potential, today’s limited and heterogeneous water information needs to become more comprehensive, transparent, interoperable, dynamic, scalable and openly accessible. Large pressures on water systems are found in coastal catchment areas that are unmonitored across the local to the global scale, indicating a large importance of these areas for nutrient and pollutant loading. The globally accessible runoff data from catchment areas that are rich in pressures from population, agriculture and general economic activity further exhibit a rapidly declining trend during recent years. Major water system changes may therefore pass unnoticed if analyzed on the basis of openly accessible runoff global data. Furthermore, large discrepancies are found between land cover databases, which may result in major uncertainties in quantification of water and evapotranspiration flows. Identified information challenges may be relatively easily overcome by making better use of available information, while other challenges such as development of consistent baselines of core data and a possible re-prioritization of water-environmental monitoring programs may be both difficult and costly.</p>
64

Making water information relevant on local to global scale – the role of Information Systems for Integrated Water Management

Hannerz, Fredrik January 2008 (has links)
Relevant information is essential for finding solutions in Integrated Water Management (IWM). Complex water systems and a need for increasing integration of sectors, actors and scales in IWM require new methods for developing and managing such information. This thesis investigates the role of information within the IWM process, as well as the main challenges for development of representative, accessibleand harmonized information. Results show how information needs and the information production process for IWM may be systematized, and indicate a large potential for information system development for IWM. However, in order to reach the full potential, today’s limited and heterogeneous water information needs to become more comprehensive, transparent, interoperable, dynamic, scalable and openly accessible. Large pressures on water systems are found in coastal catchment areas that are unmonitored across the local to the global scale, indicating a large importance of these areas for nutrient and pollutant loading. The globally accessible runoff data from catchment areas that are rich in pressures from population, agriculture and general economic activity further exhibit a rapidly declining trend during recent years. Major water system changes may therefore pass unnoticed if analyzed on the basis of openly accessible runoff global data. Furthermore, large discrepancies are found between land cover databases, which may result in major uncertainties in quantification of water and evapotranspiration flows. Identified information challenges may be relatively easily overcome by making better use of available information, while other challenges such as development of consistent baselines of core data and a possible re-prioritization of water-environmental monitoring programs may be both difficult and costly.
65

Managing water according to river basins : Information management, institutional arrangements and strategic policy support - with focus on the EU Water Framework Directive

Nilsson, Susanna January 2006 (has links)
Today, there is a general notion that water resources are best managed according to their river basins. River basin management may be approached from a wide variety of angles. This thesis focuses on information management, institutional arrangements and strategic policy support, with special reference to the EU Water Framework Directive (WFD). The overall objective is to examine strategies, possibilities and hindrances for river basin management, with the ultimate goal of identifying key aspects to be considered - and prioritised - for “successful” European water management and WFD implementation. An assessment of the information management of three transboundary water regimes in Europe showed that a technical/scientific paradigm ap-pears to dominate in river basin accords. This is visible, for example, in the data collection, which is dominated by state and environmental impact information, and the use of passive channels for communicating with stakeholders and other interest groups. The studies addressing institutional arrangements for river basin management according to the WFD showed that the implementa-tion level of the directive is relatively low – both at national and international levels. For instance, competent authorities have not been established (strictly) according to the borders of the estab-lished River Basin District (RBDs). Further, in international RBDs, the ambitions and plans for cooperation vary considerably. Despite the general low implementation level, steps have still been taken in the “direction” of river basin management. At the national level, all examined countries have established RBDs according to river basins, and at the international level, joint river basin management plans will probably be coordinated for a majority of river basins shared by EU Member States. However, the same pattern could not be discerned for river basins extending outside the borders of the EU. In order to support strategic policy making on issues related to the implementation of the WFD, two assessments were made, one addressing international co-operation and water quality in the Baltic Sea Region, and one encompassing rankings of all the newly established RBDs based on a number of identical indicators. Although there is a need to refine these assessments, they may be regarded as simple – but yet robust – models for bench-marking. / QC 20100914
66

Implementeringen av EU:s ramdirektivför vatten i kommunernas planarbete : En studie av kommunerna i Stockholms län / The Implementation of the European Water Framework Directive in the planningprocess of municipalities : A study of municipalities in the County of Stockholm

Waernbaum, Ebba January 2010 (has links)
The European Water Framework Directive (WFD; 2000/60/EC) was incorporated into the Swedish legislation in 2004 through the ordinance Förordningen om förvaltningenav kvaliteten på vattenmiljön (SFS 2004:660). The objective is that all water bodies shall reach a good status by the year 2015. In Sweden the comprehensive plans of the municipalities can play a large role in reaching these goals. A comprehensive plan deals with the long term water and land use of the municipality, which can facilitate an early consideration of water management in the planning process of the municipality. In Sweden five river basin districts have been established in accordance with the Water Framework Directive. The focus of this study is on the Northern Baltic Sea river basin district. Action strategies have been created for each river basin district, dictating what measures the authorities, among them the municipalities, need to take. The purpose with this study is to find out to what extent the municipalities have taken the action strategies regarding the Northern Baltic Sea river basin and the water quality standards set in Förordningen om förvaltningen av kvaliteten på vattenmiljön (SFS 2004:660) into account when working with their comprehensive plans. The study also sheds light on the municipalities’ view on the demands made on them and what actions can facilitate the working process. The study was made in three parts; a survey, literature studies and interviews. An overall study of all the municipalities in the county of Stockholm was made and three were selected for an in-depth study. The results of the study show that the demands on the municipalities have not been met due to lack of knowledge. The municipalities are aware of the existence of the Water Framework Directive but find it hard to interpret the environmental quality standards and the action strategies. The municipalities wish for a clearer legal definition of the environmental quality standards and a better definition of how the implementation of the action strategies can be made. The municipalities are asking for a clarification of the demands they can make on other organizations and of the demands made on them by the county boards and the River Basin District Authorities.
67

Remote sensing in shallow lake ecology

Hunter, Peter D. January 2007 (has links)
Shallow lakes are an important ecological and socio-economic resource. However, the impact of human pressures, both at the lake and catchment scale, has precipitated a decline in the ecological status of many shallow lakes, both in the UK, and throughout Europe. There is now, as direct consequence, unprecedented interest in the assessment and monitoring of ecological status and trajectory in shallow lakes, not least in response to the European Union Water Framework Directive (2000/60/EC). In this context, the spatially-resolving and panoramic data provided by remote sensing platforms may be of immense value in the construction of effective and efficient strategies for the assessment and monitoring of ecological status in shallow lakes and, moreover, in providing new, spatially-explicit, insights into the function of these ecosystems and how they respond to change. This thesis examined the use of remote sensing data for the assessment of (i) phytoplankton abundance and species composition and (ii) aquatic vegetation distribution and ecophysiological status in shallow lakes with a view to establishing the credence of such an approach and its value in limnological research and monitoring activities. High resolution in-situ and airborne remote sensing data was collected during a 2-year sampling campaign in the shallow lakes of the Norfolk Broads. It was demonstrated that semi-empirical algorithms could be formulated and used to provide accurate and robust estimations of the concentration of chlorophyll-a, even in these optically-complex waters. It was further shown that it was possible to differentiate and quantify the abundance of cyanobacteria using the biomarker pigment C-phycocyanin. The subsequent calibration of the imagery obtained from the airborne reconnaissance missions permitted the construction of diurnal and seasonal regional-scale time-series of phytoplankton dynamics in the Norfolk Broads. This approach was able to deliver unique spatial insights into the migratory behaviour of a potentially-toxic cyanobacterial bloom. It was further shown that remote sensing can be used to map the distribution of aquatic plants in shallow lakes, importantly including the extent of submerged vegetation, which is central to the assessment of ecological status. This research theme was subsequently extended in an exploration of the use of remote sensing for assessing the ecophysiological response of wetland plants to nutrient enrichment. It was shown that remote sensing metrics could be constructed for the quantification of plant vigour. The extrapolation of these techniques enabled spatial heterogeneity in the ecophysiological response of Phragmites australis to lake nutrient enrichment to be characterised and assisted the formulation of a mechanistic explanation for the variation in reedswamp performance in these shallow lakes. It is therefore argued that the spatially synoptic data provided by remote sensing has much to offer the assessment, monitoring and policing of ecological status in shallow lakes and, in particular, for facilitating the development of pan-European scale lake surveillance capabilities for the Water Framework Directive (2000/60/EC). It is also suggested that remote sensing can make a valuable contribution to furthering ecological understanding and, most significantly, in enabling ecosystem processes and functions to be examined at the lake-scale.
68

Požeminio vandens išteklių baseininio valdymo ypatumai / The Peculiarities of the River Basin Management of Groundwater Resources

Donauskaitė, Eglė 07 February 2011 (has links)
Lietuvai vykdant vandenų politiką teko įgyvendinti ES direktyvų reikalavimus. Bendroji vandens politikos direktyva numato visą vandens apytakos gamtoje rato priežiūrą ir apsaugą, tad reikalaujama įgyvendinti vandens išteklių baseininio valdymo sistemą. Pagal šią sistemą susiejami upių baseinai ir požeminio vandens telkiniai, tarp kurių Lietuvos sąlygomis ryšio nėra, juo labiau jų ribos nesutampa. Šalis išsiskiria tarp daugumos Europos valstybių, nes turi palankias geologines ir klimatines sąlygas gausiems požeminio vandens ištekliams kauptis ir tik juos naudoja geriamam vandeniui tiekti. Todėl požeminio vandens, kaip vienintelio geriamojo vandens šaltinio Lietuvoje, apsauga yra labai svarbi. Baigiamojo magistro darbo tikslas yra išanalizuoti požeminio vandens išteklių baseininį valdymą ir jo įgyvendinimą bei ypatumus Lietuvoje. Kad pasiekti šį tikslą, buvo analizuojama esama požeminio vandens išteklių baseininio valdymo sistema Lietuvoje ir bandoma atskleisti požeminio vandens baseininio valdymo efektyvumą. Darbo įvade iškelta hipotezė, kad požeminio vandens išteklių baseininis valdymas Lietuvoje nevyksta efektyviai ir realiai negali padėti siekti Bendrojoje vandens politikos direktyvoje požeminiam vandeniui keliamų tikslų. Ekspertų nuomonė pateikiama visame darbe, o pagrindinai – paskutinėje darbo dalyje. Darbo pabaigoje pateikiamos išvados ir rekomendacijos. / Lithuania had to implement the requirements of EU directives when water policy was being implemented. The Water Framework Directive provides supervision and protection of the entire water circuit and requires to implement the river basin management system. This system joins the river basins and the bodies of groundwater, which have no link in the territory of Lithuania. In addition, the borders of both the river basins and the bodies of groundwater do not coincide. Lithuania differs from the majority of other European states because it has favourable geological and climatic conditions that account for the accumulation of abundant groundwater resources – only resources used for drinking water supply. Therefore the protection of groundwater is very important in Lithuania because it is only source of drinking water in this country. The aim of fhe final Master‘s work is to analyse the river basin management of groundwater resources and its implementation and peculiarities in Lithuania. To reach this aim the present river basin management system of groundwater resources has been analysed and the efficiency of this system has been exposed. The hypothesis that the river basin management of groundwater resources in Lithuania is not efficient and it can not help to reach the aims setted for groundwater resources in The Water Framework Directive is confirmed. The opinion of the experts is provided in the work and mainly in its last part. The conclusions and the proposals are... [to full text]
69

Strategien zur Verbesserung der Stickstoffeffizienz

Schliephake, Wilfried, Müller, Peter 06 May 2015 (has links) (PDF)
In dem Bericht werden Maßnahmen vorgestellt, von denen erwartet wird, dass sie den Ertrag stabilisieren und gleichzeitig auch N-Bilanzüberschüsse und -verluste mindern. Die Maßnahmen wurden in landwirtschaftlichen Betrieben Sachsens getestet. Als vorteilhaft erwiesen sich insbesondere die biomasseabhängige Rapsdüngung, die Streifenbearbeitung, die Injektionsdüngung und die bestandesabhängige N-Düngung zu Weizen.
70

A transaction cost approach for environmental policy analysis : the case of the Water Framework Directive in the Scheldt International river basin district

Laurenceau, Marion 28 September 2012 (has links) (PDF)
This research proposes a methodology to account for policy transaction costs and to assess how they condition the implementation of policy tasks. In light of an empirical analysis of the European Water Framework Directive implementation in 4 institutional contexts, this work (1) elaborates a typology of Policy Transaction Costs (PTC) determinants and (2) depicts stakeholders' strategies to cope with PTC ('arrangements'). We distinguish three main categories of arrangements: strategies to minimize either research and information collection costs, negotiation costs, or coordination costs. This research testifies that certain policy implementation decisions can be explained by the search for PTC minimization according to contextual determinants. Policy analysis shall thus consider PTC linked to policy implementation so as to anticipate (i) the constraints policy actors will face when implementing a given policy and (ii) how these actors are likely to respond to such constraints.

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