1,720,995 research outputs found
A review of techniques available for delimiting the erodible river corridor: a sustainable approach to managing bank erosion
No full textTraditional policies for managing river bank erosion are currently being reconsidered as a result of increased awareness regarding the unsustainable nature of some forms of bank protection, and the role played by bank erosion in providing ecosystem services and supporting geomorphological functions. River managers are therefore increasingly seeking to preserve bank erosion within a defined erodible corridor. This paper provides an overview of the erodible corridor concept, focusing on the provision of guidelines for applying the concept in practice. We argue that a nested approach is required to address management objectives across a range of scales (network scale, reach scale, local scale) and review the different geomorphic tools that are available to help managers define the extent and inner sensitivity of the erodible corridor. These tools include simple rules of thumb such as evaluation of the equilibrium meander amplitude, historical approaches based on overlays of historical channel position, and simulation modelling. The advantages and limitations of each of these tools are discussed
Erosie van rivieroevers
No full textOevers staan sinds kart in het middelpunt van de belangstellingbij beheerders van oppervlaktewateren in Nederland. Niet langerbeschouwt men oevers slechts als randverschijnsel, maar alsobjecten met een duidelijk eigen plaats en functie.Het streven om te komen tot een integraal waterbeleid leidtautomatisch oak tot een meer integrale visie op oeverbeheer. Ditbetekent dat er niet alleen aandacht wordt besteed aan detechnische functies van oevers (verdediging, gladheid,afdichting, scheepvaart), maar oak aan andere functies, met namedie aangaande natuur en recreatie.Binnen Rijkswaterstaat heeft dit geleid tot de instelling van hetProject Milieuvriendelijke Oevers (PMO). Tevens is in mei 1987vanuit de Stichting CUR de preadviescommissie PC 59 gestart, dieonderzoek betreffende constructieve aspecten vanmilieuvriendelijke oevers voorbereidt.Binnen PMO of PC 59 is nog geen sluitende definitie van hetbegrip ~milieuvriendelijke oever~ overeengekomen. Milieuvriendelijkmateriaalgebruik en gelijkenis met natuurlijke oeverslijken vanuit civiel-technisch gezichtspunt de twee essentielecomponenten: Milieuvriendelijk materiaalgebruik en Gelijkenis met naturlijke oevers. De twee componenten kunnen strijdig ZlJn, bijvoorbeeld detoepassing van puin afkomstig van een sloop: milieuvriendelijk inde zin van hergebruik van materialen, niet milieuvriendelijk in de zin van een zo natuurlijk mogelijke oever.Hydraulic EngineeringCivil Engineering and Geoscience
Cambiando de enfoques rígidos a enfoques adaptativos en el encauzamiento fluvial para la navegación
No full textLa navegación es una forma de transporte favorable al medio ambiente y, por lo tanto, mejorar los ríos como vías navegables es un componente importante en el desarrollo económico. Tradicionalmente, esta mejora ha consistido en la reducción del ancho del río con la utilización de espigones y otras estructuras. Las tendencias modernas, sin embargo, proponen el cambio a enfoques más adaptativos por varias razones. En primer lugar, las mejoras en la tecnología de dragado hacen los métodos adaptivos más factibles, ampliando las posibilidades de construir con la naturaleza “Building with Nature”. En segundo lugar, se ha incrementado el entendimiento de los efectos a largo plazo después un encauzamiento fluvial rígido. Este artículo revisa las experiencias con los efectos a largo plazo, discutiendo entonces la persistencia de las percepciones que se oponen a las tendencias modernas. Estas percepciones deben abordarse en colaboración con las partes interesadas con el fin de lograr un verdadero avance en la modernización de la ingeniería fluvial.Rivers, Ports, Waterways and Dredging Engineerin
Participation des acteurs dans les prises de decision
No full textHydraulic EngineeringCivil Engineering and Geoscience
Experiences in Bangladesh with riverbank protection in a global perspective and implications for ongoing projects (PPT)
No full textPower Point PresentationRivers, Ports, Waterways and Dredging Engineerin
Modelling in applied hydraulics: More accurate in decision making than in science? (PPT)
No full textMarked differences occur between modelling in scientific hydraulic research, in hydraulic engineering and in public decision making. This study reviews ifferences in the required accuracy of model results and differences in the choice between physical and numerical modelling. Physical models are used for studying elementary processes and their interactions under controlled conditions in scientific research; for the planning and design of interventions in hydraulic engineering; and for explanation and demonstration in public decision making. Numerical models are powerful tools in scientific research, butfield applications cannot be verified or validated according to rigorous scientific standards. Hydraulic engineers use numerical models for various purposes, some requiring a high accuracy and some not. They are used to uncertainty and deal with this by means of sensitivity analyses or probabilistic approaches. Numerical models are also used for decision making on interventions that affect stakeholders, sometimes even having the last word in corresponding protocols or legislation. The suggested or perceived accuracy of model results is in this context much higher than the real accuracy. This leads to the paradoxical situation that decision makers and stakeholders put higher demands on accuracy than scientists do
Basisprincipes riviermorfologie (PPT)
No full textBetreft: Programma Tweedaagse masterclass KRW Maas 2016Rivers, Ports, Waterways and Dredging Engineerin
Short-term gains - long-term regrets: The effects of engineering large rivers in France and the Netherlands
No full textHydraulic EngineeringCivil Engineering and Geoscience
Modelling of river morphology with non-orthogonal horizontal curvilinear coordinates
No full textA numerical two-dimensional model for river morphology is extended with bank erosion. The model is formulated in curvilinear coordinates. This allows the use of a boundary-fitted computational grid, suited for rivers with a curved centre-line and a non-uni form width. Dealing with non-homogeneous bank erodibility is shown to require a non-orthogonal coordinate system. This enables the use of simple algebraic grid generators, but complicates the transformed equations. A main feature of the present study is that all coordinate derivatives in the transformed equations are replaced by grid properties that are invariant for grid rotation, such as local grid skewness and grid line divergences. This facilitates the physical interpretation of transformation terms and the estimation of their contribution to the solution. The model is verified by comparing its results with results from the original model, and by comparing computations on nonorthogonal grids with a computation on an orthogonal grid. An examination of the truncation error reveals the importance of a smooth grid point distribution for accuracy.Civil Engineering and Geoscience
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