3878 resultaten

  • Modelling hyperconcentrated flow in the Yellow River

    Auteurs: Maren, D.S. van; Winterwerp, J.C. (2009)
    Gepubliceerd in: Earth surface processes and landforms : the journal of the British Geomorphological Research Group, volume 34 (2009) nummer 4, pagina 596-612

    A large amount of the total sediment load in the Chinese Yellow River is transported during hyperconcentrated floods. These floods are characterized by very high suspended sediment concentrations and rapid morphological changes withalternating sedimentation and erosion in the main channel, and persistent sedimentation on the floodplain. However, the physical mechanisms driving these hyperconcentrated floods are still poorly understood.

  • Process-based modeling for the Yangtze estuary

    Auteurs: Chu, A.; Wang, Z.B.; Vriend, H.J. de (2009)

    A state-of-art process-based model is applied to simulate the hydrodynamics in the Yangtze Estuary in China, as a basicstep to acquaint ourselves with the morphological development and the effect of human interference in the estuary. Amajor improvement with respect to previous models for the Yangtze Estuary is that the present model covers the entiretidal region of the Yangtze River.

  • Modelling mass evacuations to improve the emergency planning for floods in the UK, The Netherlands and North America

    Auteurs: Lumbroso, D.; Bruijn, K.M. de (2010)

  • Solution of quasi-static large-strain problems by the material point method

    Auteurs: Beuth, L.; Wieckowski, Z.; Vermeer, P.A. (2010)
    Gepubliceerd in: International journal for numerical methods in geomechanics, volume 35 (2010) nummer 13, pagina 1451-1465

    A procedure for solving quasi-static large-strain problems by the material point method is presented.Owing to the Lagrangian-Eulerian features of the method, problems associated with excessive meshdistortions that develop in the Lagrangian formulations of the finite element method are avoided. Threedimensionalproblems are solved utilizing 15-noded prismatic and 10-noded tetrahedral elements withquadratic interpolation functions as well as an implicit integration scheme.

  • Correspondence on Geisz et al. Melting glaciers: a probable source of DDT to the Antarctic marine ecosystem

    Auteurs: Brink, N. van den; Heuvel-Greve, M.J. van den (2009)
    Gepubliceerd in: Environmental science and technology, volume 43 (2009) nummer 10, pagina 3976-3977

    Journal: Environmental Science & Technology.

  • Flexible model predictive control for the management of a drainage canal system under uncertain conditions

    Auteurs: Raso, L.; Overloop, P.J. van; Schwanenberg, D. (2010)

    Model Predictive Control (MPC) has been used successfully for the operational management of complex systems in a deterministic framework. Water systems very often have, among others, the following extra element of complexity: the presence of a not negligible uncertainty, generally related to the prediction of the input and represented by an ensemble forecast. Starting at the instant of prediction, the uncertainty of the forecast increases, which makes the ensemble spread out. With a proper pruning of the ensemble it is possible to create a tree of disturbances and from this a corresponding tree of decisions. At each node of this tree the decision is optimal, given the information available at that point. This control system is flexible because it considers changing of future decisions according to the ongoing scenario. This novel technique is applied to a drainage canal system in Delfland (The Netherlands) and compared with a traditional MPC. To conclude, we summarize the advantages and limits of this method, and possible future solutions to overcome the limits.

  • Simulating low-probability peak discharges for the Rhine basin using resampled climate modeling data

    Auteurs: Linde, A.H. te; Kwadijk, J.C.J. (2010)

    In this paper we aim to enhance the simulation of future low-probability flood peak events in the Rhine basin using different climate change scenarios, and downscaling methods. We use the output of a regional climate model (RCM) and a weather generator to create long, resampled time series (1000 years) of climate change scenarios as input for hydrological (daily) and hydrodynamic (hourly) modeling. We applied this approach to three parallel modeling chains, where the transformation method from different resampled RCM outputs to the hydrological model varied (delta change approach, direct output, and bias-corrected output).

  • Assessment of the Netherlands' flood risk management policy under global change

    Auteurs: Klijn, F.; Bruijn, K.M. de; Kwadijk, J.C.J. (2012)

    We assessed whether, to what extent and when the Netherlands' current flood risk management policy may require a revision. The conclusion is that the current flood risk management policy in the Netherlands can be continued for centuries when the sea level rise rate does not exceed 1.5 m per century. However, we also conclude that the present policy may not be the most attractive strategy, as it has some obvious flaws.

  • Compartimentering van dijkringen : kansrijk, maar lang niet overal

    Auteurs: Klijn, F.; Alberts, F.; Asselman, N.E.M. (2009)

    Na de ramp van 1953 pleitte de Deltacommissie voor compartimentering van Centraal-Holland. Het geadviseerde beschermingsniveau van 1:10.000 ging daar zelfs van uit. Van de compartimentering is echter niets terecht gekomen en het principe is enigszins in de vergetelheid geraakt. Rond deze tijd komen de resultaten van een recente studie beschikbaar rond de vraag óf, waar en onder welke voorwaarden compartimentering zinvol is. Het blijkt mogelijk de gevolgen van overstromingen fors te beperken, maar nieuwe compartimenteringsdijken zijn slechts zelden rendabel vanuit economisch oogpunt. Om maatschappelijke ontwrichting te voorkomen, zijn ze wel zinvol.

  • Geowetenschappelijke kennis van randvoorwaarden essentieel bij natuurinrichting Ilperveld

    Auteurs: Klein, J.; Griffioen, J.; Westerman, S.; Hensens, M. (2009)
    Gepubliceerd in: H2O : tijdschrift voor drinkwatervoorziening en afvalwaterbehandeling, volume 42 (2009) nummer 14-15, pagina 35-37

    Het Ilperveld behoort tot degrootste waterrijke veenweidegebiedenten noordenvan Amsterdam.

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