4073 resultaten

  • Simulation of subaqueous dunes using detailed hydrodynamics

    Auteurs: Nabi, M.; Vriend, H.J. de; Mosselman, E.; Sloff, C.J.; Shimizu, Y. (2009)

    We are developing a numerical model for simulating the development and migration of dunesin rivers in 3D case. The numerical model consists of three modules: turbulent flow, sediment transport andmorphology.

  • The influence of changes in tidal asymmetry on residual sediment transport in the Western Scheldt

    Auteurs: Bolle, A.; Wang, Z.B.; Ronde, J.G. de (2010)
    Gepubliceerd in: Continental shelf research, volume 30 (2010), pagina 871-882

    This study fits into a wide rresearch program from Rijkswaterstaat, RIKZ concerning the exchange of sediment between the coast and the tidal basins, Western Scheldt and WaddenSea, which are the largest basins along the Dutch Coast, over different time-scales.

  • Calibrating the regional tidal prediction of the Singapore regional model using Openda

    Auteurs: Kurniawan, A.; Ooi, S.K.; Gerritsen, H. (2010)

    The MHBox study focuses on the comprehensive analysis and understanding of residual water levels and currents and their forcing mechanism for the highly complex Singapore regional waters [1]. A deterministic hydrodynamic model application named the Singapore Regional Model (SRM) is applied [2], which focuses on representing water level and current dynamics in Singapore waters including their approaches, to ensure that the large scale features are dynamically represented in the model itself.

  • A study of variance estimators for material sampling using computerized models of contaminant heterogeneity in soil stockpiles

    Auteurs: Geels, B.; Lamé, F.P.J. (2010)

    During the sampling of contaminated soil, sampling errors are unavoidable because of the spatial heterogeneity of the contaminant distribution. The variance is a convenient indicator for the potential magnitude of these errors. Four variance estimators are constructed for use in material sampling, all of which take account of the heterogeneity and the sampling design. Based on large scale three-dimensional computerized models of contaminant heterogeneity in soil stockpiles, these variance estimators are compared using a Monte Carlo simulation of different sampling designs. The Mean Squared Error (MSE) of each variance estimator is used to assess (and compare) the performance of each variance estimator: the lower the mean square error, the better its performance.

  • Potential synergistic effects of microcystins and bacterial lipopolysaccharides on life history traits of Daphnia galeata raised on low and high food levels

    Auteur: Dionisio Pires, L.M. (2011)

    Two experiments were performed in which potential synergistic effects between bacterial LPS and microcystins were tested. It was concluded that microcystin-producing Microcystis had deleterious effects on the life history of D. galeata, but especially when the availability of high quality green algal food was limited in comparison to the supply of microcystin producing strain PCC7820.

  • Responses of the Dutch coastal system to the (semi-) closures of tidal basins

    Auteurs: Wang, Z.B.; Ronde, J.G. de; Spek, A.J.F. van der; Elias, E.P.L. (2009)

    Conference paper about effects of closures of Zuiderzee, Lauwerszee, Haringvliet, Grevelingen and Eastern Scheldt on the coast and on the remaining basins.

  • Nonlinear model predictive control of flood detention basins in operational flood forecasting

    Auteurs: Schwanenberg, D.; Verhoeven, G.F.; Boogaard, H.F.P. van den (2010)

  • Morphodynamic responds of groyne fields to the lowering of crest level of the groynes in the Waal River, The Netherlands

    Auteurs: Busnelli, M.M.; Wal, M. van der (2011)

    The lowering of the crest of the groynes in the River Waal is one of the measures being applied in the Netherlands to reduce the water levels at high water conditions. A total of 750 groynes will be lowered lengthwise by 1 to 2 meters. A side-effect is sedimentation in the main channel, due to redistribution of the discharge in the cross-section. Also, the flow through the groyne fields will increase, so erosion in the groyne field occurs. The patterns of erosion and sedimentation in the groyne fields were analyzed and the effect of the lowering of the groynes on the morphology of the groyne field was quantified. This paper addresses the morphological developments of the groyne fields and near the head of the groynes.

  • Monitoring of a railway piled embankment

    Auteurs: Duijnen, P.G. van; Eekelen, S.J.M. van (2010)

  • How ecological engineering can serve in coastal protection

    Auteurs: Borsje, B.W.; Wesenbeeck, B.K. van; Dekker, F.; Bouma, T.J.; Vries, M.B. de (2011)
    Gepubliceerd in: Ecological engineering, volume 37 (2011) nummer 2, pagina 113-122

    Traditionally, protection of the coastal area from flooding is approached from an engineering perspective. This approach has often resulted in negative or unforeseen impacts on local ecology and is even known to impact surrounding ecosystems on larger scales. In this paper, the utilization of ecosystem engineering species for achieving civil-engineering objectives or the facilitation of multiple use of limited space in coastal protection is focused upon, either by using ecosystem engineering species that trap sediment and damp waves (oyster beds, mussel beds, willow floodplains and marram grass), or by adjusting hard substrates to enhance ecological functioning. Translating desired coastal protection functionality into designs that make use of the capability of appropriate ecosystem engineering species is, however, hampered by lack of a generic framework to decide which ecosystem engineering species or what type of hard-substrate adaptations may be used where and when. In this paper we review successful implementation of ecosystem engineering species in coastal protection for a sandy shore and propose a framework to select the appropriate measures based on the spatial and temporal scale of coastal protection, resulting in a dynamic interaction between engineering and ecology. Modeling and monitoring the bio-physical interactions is needed, as it allows to upscale successful implementations and predict otherwise unforeseen impacts.

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