4075 resultaten

  • Palaeo-hydrological reconstruction of a managed fen area in The Netherlands

    Auteurs: Loon, A.H. van; Griffioen, J.; Bierkens, M.F.P. (2009)

    Knowledge of the anthropogenic impact on the hydrology of low-productive fens that are subject to environmentaldegradation is essential to improve currently utilized hydrological fen restoration strategies.

  • A software framework for construction of process-based stochastic spatio-temporal models and data assimilation

    Auteurs: Karssenberg, D.; Bierkens, M.F.P. (2010)
    Gepubliceerd in: Environmental modelling and software, volume 25 (2010) nummer 4, pagina p. 489-502

  • Application of generic data assimilation tools (DATools) for flood forecasting purposes

    Auteurs: Weerts, A.H.; El Serafy, G.Y.; Hummel, S.; Dhondia, J.F.; Gerritsen, H. (2010)
    Gepubliceerd in: Computers and geosciences, volume 36 (2010) nummer 4, pagina 453-463

    This paper describes the generic data assimilation software tool DATools. DATools can be used as standalone or within Delft-FEWS. DATools is completely configurable via XML configuration. DATools is built up of three components a Filter, a Stochastic Modeler, and a Stochastic Observer.

  • Modelling of depth-induced wave breaking over sloping and horizontal beds

    Auteur: Westhuysen, A.J. van der (2009)

    Proc. 11th Int. Workshop on Wave Hindcasting and Forecasting, in press, 2009.

  • The erodibility of grassed inner dike slopes against wave overtopping

    Auteurs: Hoffmans, G.J.C.M.; Verheij, H.J.; Hoven, A. van (2009)

    Field measurements are presented, which are the first to quantify the processes influencing the entrapment of suspended particulate matter (SPM) at the limit of saltwater intrusion in the Rotterdam Waterway. The estuarine turbidity maximum (ETM) is shown to be maintained by the trapping of fluvial SPM at the head of the salt wedge. The trapping process is associated with the raining out of fluvial SPM from the upper, fresher part of the water column, into the layer below the pycnocline. The dominant mechanisms responsible are baroclinic shear flows and the abrupt change in turbulent mixing characteristics due to damping of turbulence at the pycnocline. This view contrasts with the assumption of landward transport of marine SPM by asymmetries in bed stress. The SPM transport capacity of the tidal flow is not fully utilized in the ETM, and the ETM is independent of a bed-based supply of mud. This is explained by regular exchange of part of the ETM with harbor basins, which act as efficient sinks, and that the Rotterdam Waterway is not a complete fluvial SPM trap. The supply of SPM by the freshwater discharge ensures that the ETM is maintained over time. Hence, theETMis an advective phenomenon. Relative motion between SPM and saltwater occurs because of lags introduced by resuspension. Moreover,SPM that lags behind the salt wedge after high water slack (HWS) is eventually recollected at the head. Hence, SPM follows complex transport pathways and the mechanisms involved in trapping and transport of SPM are inherently three-dimensional.

  • Exploring multi-agent systems in aquatic population dynamics modelling

    Auteurs: Qi, H.; Li, H.; Mynett, A.E. (2009)

    This research aims to explore the concept of Multi-AgentSystems (MAS) in modelling spatial population dynamics of aquatic plants.

  • Comparison of Kalman filter and inter-model correlation method for data assimilation in tidal prediction

    Auteurs: Sun, Y.; Sisomphon, P.; Babovic, V.; Chan, E.S. (2009)

    With the objective to provide ydrodynamic information of the water around Singapore, the Singapore Regional Model (SRM) has been developed within the Delft3D numerical modelling system. The results of this large-domain numerical model arenecessarily a balance between the choices about domain, local resolution, model parameter settings and forcing.

  • Determination of the wave climate for the southern Brazilian shelf

    Auteurs: Cuchiara, D.C.; Fernandes, E.H.; Strauch, J.C.; Winterwerp, J.C.; Calliari, L.J. (2009)

  • Database of full-scale laboratory experiments on wave-driven sand transport processes

    Auteurs: Werf, J.J. van der; Schretlen, J.J.L.M.; Ribberink, J.S.; O'Donoghue, T. (2009)

    A new database of laboratory experiments involving sand transport processes over horizontal, mobile sand beds under full-scale non-breaking wave and non-breaking wave-plus-current conditions is described. The database contains details of the flow and bed conditions, information on which quantities were measured and the value of the measured net sand transport rate for 298 experiments conducted in 7 large-scale laboratory facilities. Analysis of the coverage of the experiments and the measured net sand transport rates identified the following gaps in the range of test conditions and/or the type of measurements: (i) graded sand experiments, (ii) wave-plus-current experiments and (iii) intra-wave velocity and concentration measurements in the ripple regime. Furthermore, it highlights two areas requiring further research: (i) the differences in sand transport processes and sand transport rates between real waves and tunnel flows with nominally similar near-bed oscillatory flow conditions and (ii) the effects of acceleration skewness on transport rates. The database is a useful resource for the development and validation of sand transport models for coastal applications.

  • Estimation of amorphous organic carbon/water partition coefficients, subcooled aqueous solubilities, and n-octanol/water distribution coefficients of alkylbenzenes and polycyclic aromatic hydrocarbons

    Auteur: Noort, P.C.M. van (2009)

    The aim of this work was to derive a relation between the number of specific carbon atoms in alkylbenzenes and PAHs and the average log Koc for linear partitioning between amorphous organic carbon in soils and sediments and water.

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