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OpenMI testen LSM : KPP 2015 Hydraulica Schematisaties - Zoet
Het Landelijk SOBEK Model (LSM) is ontwikkeld in het kader van het project Deltamodel en het Nationaal Hydrologisch Instrumentarium sinds medio 2010. Het is nu mogelijk om de meerdere SOBEK modellen via OpenMI (Open Modelling Interface) te koppelen. Hierdoor kan het LSM in principe worden opgebouwd als een OpenMI-koppeling van de losse modellen van de waterbeheerders (zowel RWS als de waterschappen). In dat geval is het niet nodig om bij aanpassingen in een regionaal model dezelfde aanpassingen ook in LSM over te nemen, maar hoeft er alleen een nieuw regionaal model in OpenMI gehangen te worden en de uitwisselingslocaties van dit nieuwe model met de andere modellen aangepast te worden. Het beheer van LSM wordt daardoor in principe eenvoudiger, omdat het beheer van de individuele modellen bij de verantwoordelijke waterbeheerder kan blijven liggen, en alleen de koppelingen tussen de verschillende modellen goed beheerd moeten worden. Dit rapport doet verslag van testen of de koppeling via OpenMI in de praktijk toepasbaar en hanteerbaar is.
GRADE 2012 : procedure to derive the design hydrograph
GRADE (Generator of Rainfall and Discharge Extremes) is a new methodology to provide a better physical basis for the estimation of the design discharge of the main Dutch rivers compared to the present method based on frequency analysis of extreme discharge values. This report proposes a procedure to derive the shape of the design discharge hydrograph and the accompanying uncertainty width using the synthetic GRADE discharge series for the river Meuse at Borgharen. The focus is placed on the derivation of a design hydrograph for the failure mechanisms overflow and overtopping.
Updating levee reliability with performance observations
Flood defenses are crucial elements in flood risk mitigation in developed countries, especially in deltaic areas. In The Netherlands, the VNK2 project is analyzing the reliability of all primary flood defenses as part of a nationwide flood risk analysis. In this project, as in most other reliability analyses of flood defenses, prior probabilities of relevant parameters such as ground conditions use to be based on sparse site investigation data and/or expert judgment. What is largely neglected is the observed performance during extreme events such as excessive seepage or sand boils. Using this information and thereby reducing uncertainties contributes to identifying weak spots or to increasing reliability where positive signs of performance are observed. Ultimately, this contributes to focusing investments in flood defenses where they are needed the most. This paper proposes a methodology based on Bayesian Inference for updating uncertainties and focuses on the failure mechanisms uplift and piping. Attention is paid to the system reliability effects in this failure mode, too. The methodology is applied to a case study in The Netherlands, the prior probabilities stem from the VNK2 project. The results suggest that depending on the observation, the probability of failure can either increase or decrease by about a factor 10. The findings clearly contradict the common perception, at least in The Netherlands, that if a structure survives an extreme (load) event its reliability always increases. That is only true unless bad performance-related observations have been made.
Verslag TC211 Symposium Brussel 29 mei - 2 juni Onderdeel Geokunststoffen
TC211 is Technische commissie binnen de ISSMGE (International Society for Soil Mechanics and Geotechnical Engineering) die zich bezig houdt met grondverbetering.
The influence of subsoil reaction in a basal reinforced piled embankment
The behaviour of a geosynthetic reinforcement (GR) in a piled embankment depends on the amount of arching, membrane reaction and subsoil reaction. This paper considers the subsoil reaction as described in the guidelines for piled embankments of the Netherlands (CUR 2010) and Germany (EBGEO 2010) and suggests a modification. This suggested modification leads in most cases to a larger influence of the subsoil reaction. A series of nineteen 3D piled embankment model experiments was performed, partly published earlier in Van Eekelen et al. (2012). One of the advantages of the test set-up is the ability to measure the complete load distribution. This paper compares the results of three tests with EBGEO/CUR and the suggested analytical modification and focussing especially on the load distribution between the GR and subsoil. Comparison of the predictions and measurements show that the suggested analytical modification of the subsoil reaction results in more accurate predictions.
The role of knowledge and research in two case studies on cross-border Maritime Spatial Planning in the southern North Sea
Maritime Spatial Planning (MSP) is worldwide advocated as a promising tool for implementing ecosystem based maritime spatial management, which should resolve inter-sectoral and cross-border conflicts over maritime space. The MASPNOSE project, which forms the basis for this paper, is a Preparatory Action on Maritime Spatial Planning in the North Sea, funded by the DG MARE. The project has experimented with cross-border MSP in two case studies: Thornton Bank and Dogger Bank. This was done through the exploration of the possibilities of cooperation among stakeholders and between countries establishing elements for a common agenda for the cross-border cooperation. This paper focuses on the question what the role of knowledge and research was in the two planning initiatives.
Modern geotechnical design codes of practice
Target reliabilities and partial factors for flood defenses in the Netherlands
Modern codes of practice such as Eurocode strive to provide design rules including partial factors with an appropriate level of safety for a wide range of applications. The target reliability levels and partial factors in such codes are not equally efficient for all applications, since they are calibrated to work well in both typical and unusual situations. For large engineered systems like flood defense systems with large potential consequences and substantial investments in improvement and maintenance, it is worthwhile to develop tailor-made solutions. This paper describes the approach adopted in the Netherlands to develop safety requirements to flood defenses such as partial factors for dikes within an acceptable risk framework accounting for system reliability aspects. The main steps herein are to define a risk-informed target reliability for the whole system (i.e. including all elements and failure modes), to derive target reliabilities for specific elements (e.g. dike sections) and failure modes and to calibrate partial factors on the latter. After describing those steps, the paper provides an application example for the uplift and piping failure mode (i.e. internal erosion).
Specifieke emissies naar het oppervlaktewater in het Antwerpse Havengebied
Inventarisatie van de havenspecifieke emissies op het oppervlaktewater in het Antwerps havengebied. De nadruk ligt hierbij op de emissies vanuit diffuse bronnen van PAK's, zware metalen en nutriënten. Daarnaast is er een vergelijking uitgevoerd van alle berekende emissies met de reeds beschikbare gegevens uit de Emissie Inventaris Water (EIW) van de Vlaamse Milieu Maatschappij (VMM). Op basis van gegevens uit de Nederlandse EmissieRegistratie, de Vlaamse Emissie Inventaris water en gegevens van het Gemeentelijk Havenbedrijf Antwerpen zijn schattingen gemaakt voor een 16-tal emissiebronnen die vallen onder de activiteiten zeevaart, binnenvaart, spoorwegen, wegverkeer, calamiteiten en waterbouw.
Smart levees : updating piping reliability with head monitoring
Uplift and piping are important failure mechanisms of levees in terms of their contribution to the total probability of failure of flood defense systems in the Netherlands. The reliability for this combined failure mode uses to be dominated by uncertain ground conditions, especially by the blanket thickness and the permeability of the aquifer. Such uncertainties can be reduced by incorporating additional information by means of Bayesian Updating. This study explores how active pore pressure monitoring can affect the piping reliability and how we can assess the uncertain effects of future monitoring campaigns for judging their (expected) cost-effectiveness.