4073 resultaten

  • DSS for water quality management of marina reservoir system in Singapore

    Auteurs: Fielding, M.; Schwanenberg, D.; Twigt, D.J. (2010)

    We discuss the design of an operational decision support system applied on the recirculation scheme for Marina Reservoir, Singapore aiming at the control of the reservoir's water quality. It consists of the components i) model-based forecasting of water quantity and quality using simplified zero-dimensional models and ii) an optimization algorithm for identifying optimum future control actions over a control horizon of several days. These components will work in conjunction with a comprehensive coupled 1D-3D modeling framework for the catchment and reservoir, integrated in an Operational Management System (OMS) within the scope of other work. Furthermore, an implicit stochastic approach is outlined for taking into account uncertainty in decision-making, which is mainly present in the WQ state estimation as well as in the prediction of future disturbances, i.e. quantity and quality fluxes going into the reservoir. Finally, we demonstrate the feasibility of the scheme by performing a proof-of-concept on a simplified reservoir.

  • Guidance on the design of berthing structures related to the flow velocities in ship thrusters

    Auteur: Verheij, H.J. (2010)

  • Real-time monitoring of full-scale levee testing

    Auteur: Koelewijn, A.R. (2010)

  • Monitoring and evaluation of spatially managed areas : a generic framework and its application

    Auteurs: Stelzenmüller, V.; Dalfsen, J.A. van (2010)

    The application of an ecosystem approach to management of the sea requires both integrated and strategic frameworks such as ICZM and the use of marine spatial planning (MSP) to minimize spatial use conflicts and environmental degradation. Such an integrated management promotes sustainable development based on achieving a balance of environmental, social and economic objectives.

  • Seasonal and long-term changes in pH in the Dutch coastal zone

    Auteurs: Provoost, P.; Laane, R.W.P.M. (2010)
    Gepubliceerd in: Biogeosciences, volume 7 (2010) nummer 11, pagina 3869–3878

    Recent observations and modelling studies suggest that biogeochemical changes can mask atmospheric CO2-induced pH decreases. Data collected by the Dutch monitoring authorities in different coastal systems (North Sea, Wadden Sea, Ems-Dollard, Eastern Scheldt and Scheldt estuary) since 1975 provide an excellent opportunity to test whether this is the case in the Dutch coastal zone.

  • “Sand engine“ : background and design of a mega-nourishment pilot in the Netherlands

    Auteurs: Mulder, J.P.M.; Tonnon, P.K. (2010)

  • Effects of river floodplain lowering and vegetation cover

    Auteurs: Villada Arroyave, J.A.; Crosato, A. (2010)
    Gepubliceerd in: Proceedings of the Institution of Civil Engineers - water management, volume 163 (2010) nummer 9, pagina 457-467

  • Validation of a non-linear reduced hydrodynamic model for curved open-channel flow

    Auteurs: Ottevanger, W.; Uijttewaal, W.S.J.; Blanckaert, K. (2010)

    The flow through meander bends is inherently three dimensional and may be characterized by primary flow in treamwise direction and secondary flow in transverse direction. Although, three dimensional simulations of meander bends are feasible for laboratory scale experiments, temporal and spatial scales of naturally occurring meandering rivers are much larger than those found in laboratory experiments.

  • The effect of grid resolution and weather forcing on hydrodynamic modelling of South East Asian waters

    Auteurs: Ooi, S.K.; Sisomphon, P.; Gerritsen, H.; Twigt, D.J. (2009)

    The flows in Malacca Strait and Singapore waters are the result of complex tidal interactions of the Indian and Pacific Oceans, monsoon effects and furtheratmospheric forcing. For modelling the tidal flow, the authors use the SingaporeRegional Model (SRM).

  • Discharge simulations performed with a hydrological model using bias corrected regional climate model input

    Auteurs: Pelt, S.C. van; Kabat, P.; Maat, H.W. ter; Hurk, B.J.J.M. van den; Weerts, A.H. (2009)
    Gepubliceerd in: Hydrology and earth system sciences, volume 13 (2009) nummer 12, pagina 2387-2397

    Studies have demonstrated that precipitation on Northern Hemisphere mid-latitudes has increased in the last decades and that it is likely that this trend will continue. This will have an influence on discharge of the river Meuse. The use of bias correction methods is important when the effect of precipitation change on river discharge is studied. The objective of this paper is to investigate the effect of using two different bias correction methods on output from a Regional Climate Model (RCM) simulation. In this study a Regional Atmospheric Climate Model (RACMO2) run is used, forced by ECHAM5/MPIOM under the condition of the SRES-A1B emission scenario, with a 25 km horizontal resolution. The RACMO2 runs contain a systematic precipitation bias on which two bias correction methods are applied. The first method corrects for the wet day fraction and wet day average (WD bias correction) and the second method corrects for the mean and coefficient of variance (MV bias correction). The WDbias correction initially corrects well for the average, but it appears that too many successive precipitation days were removed with this correction. The second method performed less well on average bias correction, but the temporal precipitation pattern was better. Subsequently, the discharge was calculated by using RACMO2 output as forcing to the HBV-96 hydrological model. A large difference was found between the simulated discharge of the uncorrected RACMO2 run, the WD bias corrected run and the MV bias corrected run. These results show the importance of an appropriate bias correction.

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