Publicaties

3027 resultaten

  • Stakeholders’ assessment of dike-protected and flood-based alternatives from a sustainable livelihood perspective in An Giang Province, Mekong Delta, Vietnam

    Auteurs: Duc Tran, D.; Halsema, G. van; Hellegers, P.J.G.J.; Ludwig, F.; Seijger, C.J.L. (2018)

    Construction of extensive high dike compartments has spurred land use intensification on the upper floodplains of the Vietnamese Mekong Delta. Increasingly intense rice-based farming within these compartments has changed the water dynamics of the delta, making it impossible to exploit the erstwhile benefits of floodwaters. Progressive contraction of the natural floodplains has led to reduced deposition of fertile sediments and environmental degradation, endangering the sustainability of farmers’ livelihoods. The Mekong Delta Plan recommends discontinuance of high dike construction in the upper delta and restoration of the floodplains. However, this requires a radical shift in the agricultural economy, halting intensification of rice-based farming systems and developing alternative farming systems that can flourish on restored floodplains using “living with floods” livelihood strategies. This paper explores stakeholders’ perceptions and appreciation of these contrasting farming and livelihood systems for the upper delta. It also examines the extent that alternatives to flood-based agricultural systems are viewed as feasible and attractive. We applied multi-criteria analysis (MCA) with analytic hierarchy process (AHP) to explore the views of double and triple rice farmers and experts on alternatives based on a set of economic, water management and environmental aspects. MCA results indicate a clear preference among both farmers and experts for flood-based farming systems with low dikes. Floodwater retention capacity, infrastructure for flood protection, environmental sustainability, and market stability were ranked as the most important factors contributing to livelihood sustainability on the delta.

  • An exploration of information and information management systems

    Auteur: Zijll Langhout, S. van (2015)

    Research on how systematic and reusable information management can be done and how the gaps between data and information and between information and knowledge can be bridged. The aim of the research project is to provide recommendations for effective, efficient and sustainable information management in complex, multi-party and multi-discipline processes or organizations. A specific focus is on how an information management system can support such processes. The recommendations will include methods to involve stakeholders in the process of creating the information management system, as well as recommendations for the lay-out of the information management system. In this report, these recommendations will loosely target the creation of an information management system to manage the knowledge and information pertaining to the State of the Environment (SotE) reporting for Lake Veere (Bekkenrapportage Veerse Meere).

  • Quick scan MKBA bodemdaling binnenstad Gouda : een eerste verkenning naar de kosten en baten van handelingsperspectieven voor bodemdaling

    Auteur: Kok, J.J. (2018)

    In dit rapport worden de economische consequenties van verschillende handelingsperspectieven betreffende bodemdaling in de binnenstad van Gouda geanalyseerd.

  • Methodenvergleich Bodenbewegungsprognose für das Rheinische Braunkohlenrevier : Recherche, wissenschaftliche Beschreibung und Bewertung von Methoden und Anwendungsfällen zur Berechnung von Bodenbewegungen infolge Grundwasserstandsänderungen

    Auteurs: Becker, B.P.J.; Rohe, A. (2018)

    In der Vergangenheit wurden im Umfeld des Rheinischen Braunkohlenbergbaus unterschiedliche Ansätze entwickelt, um eine Prognose der Bodenbewegungen infolge zukünftiger Entwicklungen der Grundwasserstände in Mehrschicht-Grundwassersystemen vorzunehmen. Ziel dieser Studie ist es, herauszuarbeiten, welche bodenmechanische Prozesse für die Prognose der Bodenbewegung im rheinischen Braunkohlenrevier relevant sind, und inwieweit diese in den verwendeten Methoden berücksichtigt worden sind. Darüber hinaus sollen weitere Methoden aus der nationalen sowie internationalen Literatur, die zur Prognose von Bodenbewegungen infolge künstlicher Grundwasserstandsänderungen in mächtigen Lockergesteinswechsellagerungen eingesetzt werden können, dokumentiert werden und entsprechende Anwendungsfälle dargestellt werden. Zudem sollen Methoden dokumentiert werden, mit denen an Einzelpunkten gemessene oder prognostizierte Bodenbewegungen in die Fläche interpoliert werden können.

  • Assessing safety of nature-based flood defenses : dealing with extremes and uncertainties

    Auteurs: Vuik, V.; Vuren, S. van; Borsje, B.W.; Wesenbeeck, B.K. van; Jonkman, S.N. (2018)

    Vegetated foreshores adjacent to engineered structures (so-called hybrid flood defenses), are considered to have high potential in reducing flood risk, even in the face of sea level rise and increasing storminess. However, foreshores such as salt marshes and mangrove forests are generally characterized by relatively strong temporal and spatial variations in geometry and vegetation characteristics (e.g., stem height and density), which causes uncertainties with regards to their protective value under extreme storm conditions. Currently, no method is available to assess the failure probability of a hybrid flood defense, taking into account the aforementioned uncertainties. This paper presents a method to determine the failure probability of a hybrid flood defense, integrating models and stochastic parameters that describe dike failure and wave propagation over a vegetated foreshore. Two dike failure mechanisms are considered: failure due to (i) wave overtopping and (ii) wave impact on revetments. Results show that vegetated foreshores cause a reduction in failure probability for both mechanisms. This effect is more pronounced for wave impact on revetments than for wave overtopping, since revetment failure occurs at relatively low water levels. The relevance of different uncertainties depends on the protection level and associated dike height and strength. For relatively low dikes (i.e., low protection levels), vegetation remains stable in design conditions, and plays an important role in reducing wave loads. In case of higher protection levels, hence for more robust dikes, vegetation is less important than foreshore geometry, because of expected stem breakage of the vegetation under these more extreme conditions. The integrated analysis of uncertainties in hydraulic loads, dike geometry and foreshore characteristics in this paper enables the comparison between nature-based flood defenses and traditionally engineered solutions, and allows coastal engineers to design hybrid flood defenses worldwide.

  • Model Predictive Control of salinity in a polder ditch under high saline groundwater exfiltration conditions : a test case

    Auteurs: Aydin, B.E.; Rutten, M.; Abraham, E.; Oude Essink, G.H.P.; Delsman, J. (2017)

    Surface water salinization in deltaic areas due to saline groundwater exfiltration is an important issue. Saline surface water will not be appropriate for drinking water production, agricultural and industrial use, and therefore, freshwater diverted from rivers is used for flushing the canals and ditches in coastal areas. The effects of climate change, sea level increase and fresh water availability increases the stress on deltaic areas resulting in questioning current fresh water management strategies. In this paper, a Model Predictive Control (MPC) scheme is developed and tested for combined salinity and water level control of a polder ditch. The MPC scheme is coupled with Rapid Saline Groundwater Exfiltration Model (RSGEM) developed for fast calculation of exfiltration flux and concentration in a low-lying polder. For the test case presented in this paper, real data from Lissertocht catchment in Netherlands is used for RSGEM to see the performance of the MPC scheme for a real scenario. With open space for further research, results presented on this paper show that MPC of salinity in polders is capable of dealing with saline groundwater exfiltration modeled by RSGEM.

  • Werkplan watersysteemrapportage Oosterschelde en kenniscommunity : voor het opstellen en actueel houden van een digitale watersysteemrapportage

    Auteurs: Nolte, A.J.; Ottow, B.T.; Stolte, W. (2017)

    Dit werkplan behandelt twee generieke vragen: 1)Hoe kan met (nut voor meerdere partijen een brede watersysteemrapportage worden opgesteld?, 2)Hoe kan een watersysteemrapportage actueel gehouden worden?De beantwoording wordt toegepast op de Oosterschelde, maar is tegelijkertijd bruikbaar voor andere wateren. Een nevendoel is het creëren van een gedeeld beeld en een gemeenschappelijke taal rondom begrippen als kennisbasis, kennismanagement en kenniscommunity en rondom de mogelijkheden van digitaal rapporteren gebruikmakend van moderne technieken en ontsluiting via internet. Uitganspunt van het werkplan is dat een kenniscommunity-dat wil zeggen een samenwerkingsverband van partners met als gemeenschappelijk doel om de systeemkennis van de Oostersehelde te borgen en actueel te houden-een voorwaarde is. Door middel van de kennis community en de daaraan ten grondslag liggende afspraken, organisatie en middelen (tijd en budget) is continuïteit geborgd.

  • What is the Ghijben-Herzberg principle and who formulated it?

    Auteurs: Post, V.E.A.; Houben, G.J.; Engelen, J. van (2018)
    Gepubliceerd in: Hydrogeology journal : official journal of the International Association of Hydrogeologists (IAH) (2018), pagina 1-7

    It has been suggested in a number of historical notes that it was neither Willem Badon Ghijben nor Alexander Herzberg who formulated the famous principle now carrying their name, which relates the water-table elevation to the depth of the freshwater–saltwater interface in coastal aquifers. In this paper, a systematic review of the literature pre-dating the publication of their work is presented. The aim is to establish to what extent these previous works captured the essence of the Ghijben-Herzberg principle, that is, the combination of a correct conceptual model of the hydrogeological conditions with a quantitative relationship. It was found that references to coastal fresh groundwater reserves can be traced back to Roman times, while the earliest detailed descriptions of a freshwater lens that could be found dates from the eighteenth century. The correct understanding of the hydrostatic equilibrium between fresh and salt groundwater is evident in works from the early nineteenth century. However, it was Badon Ghijben and Herzberg who combined this with the correct understanding of the groundwater conditions of a freshwater lens. It was further found that Herzberg had already recorded his findings in 1888 in a hand-written report, confirming speculation that such a report might exist.

  • Wave overtopping over dikes with oblique wind and swell waves

    Auteurs: Werf, I.M. van der; Gent, M.R.A. van (2018)
    Gepubliceerd in: Coastlab18 : proceedings of the 7th International conference on the application of physical modelling in coastal and port engineering and science (Santander, Spain, May 22-26, 2018) (2018), pagina 1-8

    Most guidelines on wave overtopping over coastal structures are based on conditions with waves from one direction only. Here wave basin tests with oublique wave attack are presented where waves from one direction are combined with waves from another direction. This is especially of importance for locations where wind waves approach a coastal structure under a specific direction while swell waves apporach the coastal structure under another direction.

  • Coastlab18 : proceedings of the 7th International conference on the application of physical modelling in coastal and port engineering and science (Santander, Spain, May 22-26, 2018)

    Originally published in 2018

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