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This thesis is about the behaviour of a falling apron made from 'poorly sorted' material. It is a follow-up of a report, which was made by a Dutch student, Marc van der Hoeven, with the title: "The behaviour of a falling apron". In the end of the last century a complex river training work had to be done in con- nection with the construction of the Jamuna Bridge in Bangladesh crossing one of the largest rivers of the world. The Jamuna River has a strong changing character and the morphological behaviour is difficult to predict. By means of two banana-formed guide bunds the span of the bridge could be reduced from 15 km to 5 km. The constriction forced to an additional protection of the guide bunds. At the toe loose rock material was dumped, which 'fall' down' and covers the slope when erosion occurs. This is the reason why this kind of exibel protection is called 'falling apron'. In the previous study from Marc van der Hoeven only 'well sorted' material was used for the experiments, material with a narrow grading. In reality these falling aprons are made from material with a wide grading, called 'poorly sorted' material. For this reason a further study was demanded from the contractor Ballast-Ham-Dredging from the Netherlands. The experiments in a flume were mainly done with the aim to get information about the setting process of a falling apron, to determine the angle of the slope and the thickness of the protective layer after a ow attack. In two experiments it was found that the developing slope angle was approximately 1 : 2 and the setting process was evenly spread over the entire slope. A layer with an average thickness of the characteristic stone diameter of D50 protected the emerging slope. This single layer does not stop the erosion, but it slows down the scour development and this even better in comparison to the 'well sorted' material.

This study extends the theoretical approach developed by JUMELET [2010] to acquire a physical description of the notional permeability coefficient applied in the VAN DER MEER stability formulae [1988]. Van der Meer introduced this coefficient to ensure that the permeability of the structure is taken into account, however due to the empirical character of Van der Meer equations and because prior to Jumelet's research there was not an available physical description of the notional permeability factor, the determination of this factor was rather vague. Because of the fact that the stability relationship includes the P-coefficient, it has to be estimated somehow and, therefore, the research carried out by JUMELET [2010] is, to some extent, the starting point to achieve the required physical description of the notional permeability coefficient. To obtain this physical description, the volume-exchange model is introduced, in which the external and internal processes that take place within a breakwater are coupled. The external process is described by a wave run-up model while the internal process is described by the „Forchheimer‟ equation for the water flow through a porous medium. According to JUMELET [2010], the notional permeability parameter P is highly related to the run-up reduction coefficient from the volume-exchange model, and thus Jumelet defines an expression for this coefficient by means of coupling the notional permeability factor with the volume-exchange model. Because of the simplicity of the notional permeability coefficient formula developed by JUMELET [2010], further research is required to analyze the actual correlation between the notional permeability factor and the so-called run-up reduction coefficient (obtained from the volume-exchange model). This study focuses on developing a general formula for the notional permeability coefficient based on JUMELET [2010] and analyzing the real influence of the hydraulic parameters and structural properties on the P-factor. As stated by JUMELET [2010], the permeability of the structure depends not only on the structural properties but also on the hydraulic parameters. In this way, a physical description of the notional permeability coefficient is given and can be applied in Van der Meer stability equations to design breakwaters. Moreover, a damage level analysis has been performed to compare the observed damage by VAN DER MEER [1988] with the estimated damage through the combined method of Jumelet's model, the generalized formula for the notional permeability coefficient and Van der Meer stability equations, which leads to introducing the combined method as a tool to determine the maintenance policies in breakwaters by taking into account the damage that waves causes on them.

The purpose of this report is to investigate the differences in overtopping characteristics over the crest of a rubble mound breakwater when the crest is made either impermeable or permeable. Among numerous characteristics that are effected by a modification in the permeability of the crest, this report looks specifically into three separate aspects: the design level changes that are caused by modifications in the permeability of the crest, a comparison of the total and sector-wise overtopping discharges and finally the differences in spatial overtopping intensities between the two. By looking into two well-known overtopping design guidelines for overtopping, namely, Owen and Eurotop, this report aims to look at the differences it would make in designing a breakwater with either an impermeable or a permeable crest. This is done by building a breakwater model in a wave flume and comparing it with the existing guidelines and assessing the changes that best represent the modified model. It is also important to observe how this physical modification of the crest affects the overtopping discharges and spatial overtopping intensities behind the crest of the breakwater. This will be relevant for designers or contractors tasked to make changes to an existing breakwater that results in its crest becoming impermeable. An insight into the overtopping discharges and intensities will be extremely useful to be able to predict the overall changes and cater for them.

In this report will be explained how breakwaters can be made with the use of Elastocoast, a sort of glue. This makes it possible to fix the individual rocks, and allows repetitive tests possible with exactly the same layer properties. We made six samples of breakwater rock layers, made with Elastocoast and stones, which can be placed and tested in the wave flume. For doing tests it is important to know the properties of the breakwater, such as the grain size distribution, the porosity and the permeability. The permeability and porosity tests were performed on smaller parts than the slabs to be used in the model breakwater. After making the little samples we made the large ones, on the same way, for use in the wave flume. For the testing of the permeability we used a construction in which we could let water flow through the samples. This report shows the results of our tests, so these results can be used for further purposes, when other people use these breakwater samples.

For this project, Environment Mapping & Surveying (EMS) from South Africa has provided two pressure meters for wave measuring. These pressure meters give a value for the pressure, which must be converted to pressure and after that to a Rayleigh distribution and a wave spectrum. Therefore is the purpose of this report to test the pressure meter and to convert the outcomes of the pressure meter to wave heights, resulting in a Rayleigh distribution and a wave spectrum. At first, there were calibration tests in still water to measure the hydrostatic pressure. The pressure meter was lowered in the water, with some stops, hanging still. At that moment the water depth could be found in the graph of the measured values in the time, so the relation between the water depth and the measured values is found. With that relation it is possible to find the relation between the measured values and the real pressure. After this, the verification tests are done. These tests are done in the Delta Flume of Deltares, during the Bardex II project. The pressure meter was lowered into the flume, to measure the waves that were made for the Bardex II project. After this, the outcomes were converted by three Matlab-scripts into a Rayleigh distribution, a wave spectrum and some characteristic values, like Hs and Hm0. These figures and the values are compared to the measurements of Deltares to find the accuracy of the pressure meter. The comparison with the measurements of Deltares shows that the pressure meter has an accuracy of five percent. The most important characteristic values are even more accurate, up to one or two percent. The figures of the Rayleigh distribution and the wave spectrum are comparable to the figures of Deltares. These outcomes make the pressure meter a quite accurate instrument to measure waves. Due to the fact that this instrument is inexpensive in comparison to other wave meters, it is a very usable instrument for fieldwork or low-budget projects.

Mangrove forests have been proven to be an efficient system in attenuation of the wave energy. Therefore, they may be incorporated in the construction of coastal dikes and contribute to decreasing the total cost of such a project. This may be achieved by lowering the dike crest, lesser usage of the land or applying softer revetments. Each location where a coastal dike is to be constructed is characterized by its specific, bathymetric and met-ocean conditions. Different mangrove vegetation fields also affect the extent of wave height decay and have an impact on the total costs of a dike construction. Prior to making the decision about including mangroves in a costal dike project, a question must be answered whether or what magnitude of these savings will be made. Vietnam is one of the countries, where low-lying and deltaic regions are often flooded during extreme typhoon events and therefore the construction of flood defenses takes place on a large scale. Furthermore, the climate and conditions at the most of the Vietnamese coastline are favorable for plantation and growth of the mangroves. For that reason, Vietnam is chosen in this study as a case location for which the generic results of this study will apply. These results allow assessing the total cost savings of a coastal dike construction by incorporating mangrove vegetation for a given location, regardless of its site specific conditions. The analysis made in this study showed that the costs of a coastal dike construction in Vietnam can be effectively reduced by incorporating mangrove vegetation in the design. The extent of this reduction is subjected to the vegetation pattern, which is a function of various parameters i.e. growth stage of the trees, length of the forest, as well as the met-ocean conditions such as tidal amplitudes and storm surge levels. A 0.25m reduction in wave height leads to the total savings of around 0.25mln Euro per one running kilometer of a 3m high dike, when utilizing a hard revetment. If the 0.25m wave height reduction results in the possibility of applying soft revetment such as the Vetiver grass, these savings dramatically increase to the value of 0.9mln Euro per kilometer of a dike. These construction cost savings can already be achieved by planting 200m mangrove vegetation, where the sparsely distributed mangrove trunks (0.2-0.6 unit/m2) of varying diameters from 0.2 to 0.7m will be the elements obstructing wave propagation. Hydrodynamic simulations have proven that the emergent mangrove canopy is the most effective in attenuating wave height. In such scenarios, when the water levels are higher, the 400m long mangrove patch reduces wave height up to 0.70m. As a result, the cost of constructing 1km of a 6m high dike, can be reduced up to 1mln and 2.3mln Euro in cases where concrete blocks or reinforced grass are used respectively. The graphs and formulas developed in this research may serve as a first approximation during feasibility studies or conceptual designs of a coastal dike incorporating mangrove vegetation. They allow calculating the design wave height attenuated by a site specific or planned for the restoration mangrove forests for different design met-ocean conditions. Calculated wave reduction coefficient can be later on translated to the cost savings of a “Vietnamese” coastal dike raised behind the mangrove forest.

This report gives a short overview about the experiences of participation in coastal protection projects in Germany. The report gives no detailed description and evaluation of participation methods. In Germany, there exists a minor experience with participation in coastal protection projects. Much greater experience resulted from projects which are carried out in other fields e.g. environmental conflicts, enhancement of airport areas and so on. Only two examples exist where the process of participation had been started before a measure was applied Timmendorfer Strand / Scharbeutz and the Integrated Coastal Protection Management Plan of Schleswig-Holstein. The experience of these two projects shows that participation has a positive effect both on the process of the project and on the stakeholder.

The problem formulation of this quick scan is twofold: Is it possible to fully incorporate the citizens' perspective (for example in the form of experiential value) in a socio-economic evaluation? And does it serve a useful purpose? In this context, the concept of the citizen denotes the user of the (project) site, including neighbouring residents, other authorities, companies and interest groups. There are a variety of methods for incorporating the citizens' perspective into an impact assessment. We can make a distinction for instance between interactive incorporation or open plan process, or substantive incorporation, i.e. via a research-based evaluation. To address the problem formulation, a number of key economic evaluation methods will be highlighted first, before concentrating on the methods used to measure experiential value - a substantive approach to defining the citizens' perspective. Lastly, an attempt will be made to set out the practical aspects of the citizens' perspective in a socio-economic evaluation. Integrating the citizens' perspective as a credible component of a socioeconomic evaluation is both a feasible and meaningful activity. Examples include the Multi Criteria Analysis, which typically embraces experiential value as a credible component, or the Economic-Ecological-Emotional method, which plots out economic, ecological and social assessments. Ideally, impact assessments such as MCA or the Economic-Ecological-Emotional method should be carried out interactively in consultation with the general public. This not only strengthens the support base of the project in which the assessment is being conducted, but also the support base of the results of the assessment itself. Consequently, the local knowledge used in the impact assessment is safeguarded. The citizens' perspective can also be incorporated in an SCBA. There is however very little consensuses among experts as to whether this serves a practical purpose. Moreover, the feasibility of monetarising the citizens' perspective is a hotly contested issue in the 'battle of the methods'. In a nutshell, proponents believe that monetarisation is the only viable method for adding credibility to the citizens' perspective; provided it is measured properly and accurately. Opponents raise substantial methodological objections and also refute the usefulness, as they believe (among other things) that politicians themselves are responsible for incorporating the citizens' perspective.

This document has been produced to provide a tool to project managers to enable them to quickly assess whether or not participation is the right thing to do and the key Dos and Donts of participation. An example of a Community Engagement Plan in the UK is discribed.

The wave overtopping simulator is a device which is able to simulate overtopping waves at the crest of a dike and at the inner slope. The device has been used in the ComCoast project to test a traditional dike section with grass and the SGR, the Smart Grass Reinforcement, placed in May 2006. This report describes in the first part (Chapters 1-6) the design, construction and calibration of the 1 m wide prototype of the wave overtopping simulator, as it was performed from May July 2006, under the ComCoast programme. This first part has also been reported as a final version 2.4 in November 2006. The second part continues with the actual construction and testing of the real wave overtopping simulator and the use of it during testing at the dike at Delfzijl, all under the ComCoast programme. Further, the measurements itself and analysis of velocity and flow depth during this testing has been described. Also the work of Bosman, as performed in this project as a MSc-thesis, has been summarised. This second part describes the period from November 2006 to August 2007.

In January 2001 a reduced tidal regime was introduced in Polder Breebaart, a polder located in the northern-east part of the Province of Groningen (The Netherlands). This reduced tidal regime was achieved by building a culvert in the seawall, connecting the polder with the seawater from the Dollard, a part of the Ems-estuary. The aim was (1)to develop and restore a brackish water area with natural abiotic and biotic processes. (2)to create an opportunity for migratory fishes to migrate from the sea into freshwater and vice versa. (3) to increase environmental awareness and public support for conservation. A monitoring program was carried out in order to follow the changes in morphological, physical and biological processes. The results of the bottomdepth measurements show that sediment accumulates in the channel. This channel had been dug out as part of the restoration operation. In the first two years (2001-2002) sedimentation was about 30 cm. In order to stop this deposition, the maximum water level in the polder was lowered approximately 15cm from April 2003 onward, to force higher water velocities at outgoing tide causing more resuspension. Despite this, sedimentation was still about 15cm in the period 2003-2004. The distribution of salinity-concentrations within the polder shows a weak fresh-to-salt gradient over a short distance of approximately 600m between the outflow of the freshwater supply of the fish ladder and the culvert in the seawall. Within time salinity varies from 0,7 to 24. This salinity-range is similar to that of a nearby location in the Dollard, outside the polder. Nutrient concentrations (phosphate, nitrate) and concentrations of suspended matter correspond likewise between the two sites. The original vegetation at the borders of the channel disappeared completely. Species adapted to salt water appeared, such as Glasswort (Salicornia sp.), Annual seablite (Suaeda maritima), Lesser sea spurrey (Spergularia salina) and Sea aster (Aster tripolium). The rather rare species of Cotula coronopifolia (Common brassbuttons) settled on several locations on the transition to the grassland. Benthic fauna consisted mainly of about four species (max 8) of which the ragworm Nereis diversicolor was the most important one. In 2004 total density of benthic individuals decreased drastically compared with 2003. Moreover nearly 95% of these individuals consisted of ragworms. The ragworm is

The present report deals with the application of a provisional Smart Grass Reinforcement (SGR) system in 2006 for full scale testing of increased overtopping at the Groningen sea dyke test section near Delfzijl, as envisaged in 2007. The SGR has been placed at two strips of 4 m wide: one primary strip at the basic test site and one at a secondary test strip for additional testing. The placement of the SGR followed the awarding of this system (Report of 10 November 2005) to the consortium of Royal Haskoning and Infram), as the most feasible system for reinforcement of the dyke crest and inner slope of wave overtopped dykes. The activities for the application of the SGR, included pre-engineering, preparations, installation and follow-up. The activities that have been conducted under the responsibility of the consortium of Royal Haskoning and Infram, many other parties contributed as well: subconsultants FlevoGreenSupport and Queens Grass, Huesker (Germany), four students of the Technical College Leeuwarden. Moreover the ComCoast project organization (RWS/CUR and partners Water Board Hunze and Aas, Province of Groningen and Municipality of Delfzijl) were actively involved. The main part of the present report lays down in brief the preparatory activities (Chapter 2), the installation activities (Chapter 3) and the follow-up treatment (Chapter 4). In Chapter 5 conclusions are drawn and recommendations made. Details can be found in the appendices attached to this report: Appendix A: Photographs of situation of the SGR during the inspection visits; Appendix B: Reconnaissance of placement method and type of geosystem; Appendix C: Typical results of grass cover analysis for fertilization (follow-up treatment). The provisional application of the SGR for obtaining a representative test site in 2007 has probably been successful, in spite of many difficulties that had to be overcome. This can be seen from the photographs in Appendix A and Chapter 3. To date, a positive outcome is not sure yet, as there is still doubt on the degree of intertwinement of the grass roots with the geosystem. Hence, further checking of the monitoring strips, next to the test sections, shortly before testing in Mach 2007, will be required to ascertain the required functionality of the SGR. Looking back, the application of the Big Roll method has appeared as not really feasible: elaboration of a smart system for placement, such as indicated earlier by the consortium, should have aimed at from the beginning. A firm statement can be made here that the Big Roll method cannot be made feasible for large-scale application of SGR and further research is needed unconditionally for smart installation techniques of SGR, in combination with a suitable reinforcement system. As regards the unique character of the tests, we certainly hope for a positive outcome of the adequacy of the provisional SGR and for positive test results. Hence, awaiting the outcome of the check on the SGR adequacy shortly before the beginning of the tests next year, full-fledge preparations for the tests, are being continued.

This document is the final report of a Master thesis research. The research was executed as cooperation between Delft University of Technology, ARCADIS and ComCoast as part of The Road and Hydraulic Engineering Institute of the Directorate-General of Public Works and Water management (RWS DWW). In this report, the hurricane defence system of St. Bernard Parish is analysed and ComCoast like solutions are sought in order to make the area safe for a new Katrina. This Master Thesis analyses the failure of the St. Bernard Parish coastal defence system. Subsequently, it develops spatial integrated solutions for the coastal defence zone, using the coastal defensive strategies, which follow from the ComCoast-concept. Additionally, the effects of wetlands on a storm surge are investigated by means of an analytical analysis and a numerical model. It was concluded that catastrophic failure of the coastal defence system could have been prevented if the primary dike was not partly constructed of poorly non cohesive materials. Some basic constructional calculations and a quick study on environmental impacts made clear that the ComCoast alternatives; Overtopping resistant dike and Foreshore recharge, offer the most suitable solutions for the St. Bernard Parish area. The study on the effect of wetlands on a storm surge showed that it can both lead to a decrease, as an increase of the eventual storm surge height at the dike. The analytical and numerical approach has increased the understanding of the hydraulic behaviour of the system.

Climate change will cause increasing physical loads on the flood defence of the Province of Groningen along the North Sea over the next decades. This is caused by a sea level rise between 15 and 35 centimetres whilst the ground level is lowering between 38 and 48 centimetres until the year 2050. This results in salt-water intrusion into the land surrounding our coasts. The opinion of (DWW (Dienst Weg- en Waterbouwkunde of Rijkswaterstaat) is that it is no longer feasible to continue traditional flood management methods where the line between land and sea is keeping out tidal waters. In the ComCoast project2, we recognise the need to develop new sustainable flood management strategies in order to influence planners to anticipate future developments. With the facts mentioned above the main question (for this research) is formulated as following: Which ComCoast-solutions are possible in the Province of Groningen and what are the possibilities to implement these in the Province of Groningen? This question is answered by studying literature and interviews. To obtain the correct information four cases are selected and for those cases as many as possible stakeholders are interviewed. For one case only one stake-holder is interviewed. To obtain more information about ComCoast in general two persons are interviewed. A result of the literature study, research in the coastal area and the interviews is that it appeared that there are five ComCoast-solutions. Two of them are foreshore solutions and three landward solutions. 'Foreland protection' and 'foreshore recharge to restore the coastline' are foreshore solutions. The landward solutions are 'overtopping defence', 'managed realignment' and 'regulated tidal exchange'. There are three different motives for applying a ComCoast-solution. The first motive is to increase the safety of the inhabitants of the coastal areas. Reduce the increasing salt intrusion is the second motive. The last motive is to realise spatial needs. Each solution relays on different motives. Table 0.2 shows the motives for each solution including traditional flood management. In this report components are formulated to define right opinions of the potential stakeholders. The components are a result of studying literature. In the selected cases Breebaart, Perkpolder, Ulsderpolder and GOG Kruibeke are farmers (including agricultural organizations) in most cases the only opponent. Losing land is the mean reason. Nature conservation organisations and the higher authorities are in all cases patron. The waterboards are in the most cases neutral and the communities are in all cases at least neutral. In the case Perkpolder is one commercial partner also patron. The result of this information provides criterions to decide the possibilities of the solutions. There are two measurable criterions which define the possibilities of a solution in an area. The first is 'missing buildings' and the second is 'missing deep channel/fairway'. Measurable criterions which define the attraction are 'attendance secondary dyke', 'attendance silence area', 'attendance agricultural area' and in some cases missing deep channel/fairway.

The Dutch coast carries a variety of values. With its diversity in dune areas, its shallows and the delta areas, the coastal area of the Netherlands has a high ecological value, forming a unique biotope for a great variety of plant and animal species, and providing an important foraging area for migrating birds. The economic importance of the Dutch coast is significant as well. The coastal waters provide a large area for the fishing industry and in the wide dunes drinking water has been extracted since the nineteenth century. The Dutch coast is the gateway to the ports of Rotterdam and Amsterdam and it also attracts millions of tourists every year. Furthermore, the coastal area is popular as a residential and as an agricultural area. Finally, the Dutch coast carries many socio-cultural values. For centuries, the coast has played an important role in securing the safety of the hinterland while the image of the coast with its dikes, dunes and water works is characteristic of Dutch cultural history. Against this backdrop, the Directorate-General for Public Works and Water Management (Rijkswaterstaat) has established the umbrella project Water Assets within the organisation for water exploration (WVK). The most important reason this project has been established is that in the past the costs were often a deciding factor in the specification of policies on water, while the assets of water management were often not considered in detail. Participants in the Water Assets project are, among others, the National Institute for Coast and Sea (RIKZ) and the National Institute for Inland Water Management and Wastewater Treatment (RIZA). In the context of salt water management, the RIKZ had two case studies1 carried out by the Institute for Environmental Issues (IVM) and Resource Analysis (RA). The first case study is aimed at an Integrated Coastal Zone policy, in which various options of coastal management of the Hondsbossche Zeewering are evaluated. The second case study investigates the idea of a Veluwe on Sea. In this case study, the effects of the introduction of a natural sea reserve in the Voordelta area are evaluated. The central question in the Water Assets project is how to make the benefits of integrated water management and policy visible. It is all about quantifying the benefits and disadvantage of certain actions, comparing the different dimensions of certain effects and balancing both against each other. It was decided to split the project three ways into ecological (Green issues), economic (Financial issues) and socio-cultural (Opinions) methods of evaluation. Management and legal issues in this study do not form separate aspects; they are tools or they are part of the three abovementioned topics.

This is intended to be a short, practical booklet which is a step-by-step toolkit for those working with local communities. It is just one part of a range of work to improve our community relations. The information within this booklet has been taken from Building Trust with Communities, a background report produced as part of the Building Trust in Local Communities (BTiLC) project. The report contains detailed support information and provides the policy background and context as well as practical advice based on Environment Agency research and experience. The Building Trust with Communities Easinet site contains the full background report and this toolkit with links to other useful information.

The requirements for this literature review were set out in 5.1 as detailed in the Environment Agencys proposal for ComCoast work package 4 stakeholder dialogue and communication. The aims were: 1) To review literature relevant to the BTwC and ComCoast to understand the main messages and evidence to support improving public participation and engagement around flood risk, and 2) To understand what better public participation should and can deliver. Following discussion with Environment Agency staff, the agreed focus for the literature review was to consider: what does the literature provided tell us about how to make public participation and engagement around flood risk most effective in terms of how it is approached, and what it can and should deliver? A total of 45 sources of information were reviewed. The results of the review are provided in three sections: key messages (this paper), evidence in support of key messages (appendix 1), and practical guidance and tools (appendix 2).

De Zeeuwse kust staat onder druk. Naar verwachting zal de zeespiegel deze eeuw ongeveer 60 centimeter stijgen door klimaatverandering. Niet alleen de zee, maar ook de rivieren zorgen naar alle waarschijnlijkheid voor een stijging. De deltawateren zijn nu weliswaar afgesloten van Rijn, Maas en Schelde, maar in de toekomst wordt wellicht de estuariene dynamiek hersteld. Grotere hoeveelheden rivierafvoeren worden dan geborgen in de Zeeuwse wateren. Behalve het water zorgen economische factoren voor druk op de kustzone. De groeiende Nederlandse bevolking heeft door toenemende welvaart meer te besteden en meer vrije tijd. Zeeland is met rust en ruimte in trek als recreatieoord. De toeristische sector heeft echter een flinke kwaliteitsimpuls nodig om de vakantiegangers te blijven trekken. Daarnaast moeten effecten op de natuur van de verdieping van de Westerschelde en de aanleg van de tweede Maasvlakte volgens de Europese richtlijnen gecompenseerd worden. Natuurcompensatie vindt plaats in het kustgebied van de provincie Zeeland. Genoemde ontwikkelingen op het gebied van kustveiligheid, economie, recreatie en ecologie vragen om ruimte in de kustzone. De problemen zijn veelzijdig en de ruimte is beperkt. Behalve dat problemen worden aangepakt, worden tevens kansen gecred. Integratie van meerdere functies in de kustzone ligt voor de hand, een zogenaamde multifunctionele kustzone. Een multifunctionele kustzone is een kustzone waar de waterkerende functie van de zone gecombineerd wordt met meerdere andere functies, zoals woningbouw, recreatie, natuur et cetera. Gezien de complexiteit van het geheel speelt het proces een belangrijke rol. Dit proces staat in het rapport centraal en heeft geleid tot de volgende probleemstelling: Op welke manier kan het proces voor de ontwikkeling van een multifunctionele kustzone in Zeeland geoptimaliseerd worden? Door de vele actoren, belangen en functies, die gepaard gaan met een multifunctionele kustzone, lijkt een interactief proces onvermijdelijk. De literatuur beschrijft diverse elementen die van belang zijn voor het goede verloop van een interactief besluitvormingsproces. Aangezien geen van de theoriezich specifiek richt op een multifunctionele kustzone, is gebruik gemaakt van literatuur met betrekking tot meervoudig ruimtegebruik. Alle elementen, die in twee of meer van de bestudeerde theorienaar voren komen, zijn geselecteerd als kernelement voor het proces. De kernelementen van het proces zijn elementen, die cruciaal zijn voor een optimaal interactief besluitvormingsproces van meervoudig ruimtegebruik. De kernelementen zijn participatie, openheid, sense of urgency, winst, personele bezetting en inhoud. De theorie wordt getoetst aan de hand van de praktijk. Drie processen van kustprojecten verspreid over Zeeland en Noord-Holland zijn geanalyseerd aan de hand van de kernelementen. Daarbij is de volgende definitie van een optimaal proces gehanteerd: Een optimaal proces is een proces dat leidt tot een resultaat dat binnen een afgesproken termijn ter besluitvorming kan worden voorgelegd en dat een breed maatschappelijk draagvlak heeft. Per casus zijn projectleiders en een tweede partij geerviewd. Diepte interviews en enqus geven de beoordeling van de kernelementen en van het proces, gebaseerd op draagvlak en voortgang, weer. Daaruit komen interessante punten naar voren. Participatie van alle partijen blijkt niet noodzakelijk. Wel dienen alle belangrijke partijen betrokken te zijn. De gekozen bestuursstijl is van weinig invloed, zolang er voor een participatieve stijl gekozen wordt. Belangrijk bij dit punt is dat teveel verschillende stijlen, draagvlak en voortgang van het proces reduceren. Openheid van proces en informatie is cruciaal voor een optimaal proces. Duidelijkheid over de rol van partijen wordt verscheidene keren met nadruk genoemd als kern van succes. Daarnaast moet er voor de partijen een vorm van winst te behalen zijn. Ongelijkheid in winstmogelijkheden reduceert het draagvlak en de voortgang van het proces. Het element personele bezetting is geherdefinieerd. Niet een zware personele bezetting is essentieel voor het proces, maar de personele kwaliteit. Netwerkcapaciteiten, enthousiasme en inzet zijn individuele kwaliteiten, die essentieel zijn voor een optimaal proces. Deze kernelementen zijn noodzakelijk voor een optimaal interactief besluitvormingsproces, maar zijn individueel geen voldoende voorwaarde. Inhoud en sense of urgency vertonen geen positieve correlatie met een optimaal proces. Een zekere mate van sense of urgency en openheid van inhoud zijn wel noodzakelijk voor de start van het proces. Beide hoeven niet in grote mate aanwezig te zijn voor het goede verloop van het proces. Interactieve besluitvormingsprocessen leveren uiteindelijk resultaat op. De oplossingen van de geanalyseerde casus zijn onder de loep genomen. Bijna alle gekozen varianten hebben een sterk behoudend karakter. De zeewaartse versterking van de kust kan veelal op het grootste maatschappelijke draagvlak rekenen: de huidige situatie wordt zo min mogelijk aangetast.

Report on laboratory tests on a crest drainage dike; investigation if a channel in the crest of the dike is able to decrease the amount of overtopping over the dike. Chapter 2 provides details about findings from previous studies and the relevance of those findings to this research project. Available literature on wave run-up and wave overtopping are also reviewed and summarised. Research performed on wave overtopping layer thickness and the overtopping flow velocities are studied. Formulae to calculate layer thickness and velocity are summarised in this section. Additionally, scaling laws and scale and model effects will be explained. Section 2.6 describes the fundamentals of the crest drainage dike and the expected behaviour during an overtopping event. After the literature review, the objectives and methodologies were considered. The final section of Chapter 2 is focused on revising objectives and methodology. In Chapter 3 the model setup, measurement techniques and test programme are described. Chapter 3 also includes the calibration of measuring devices and methods of data analysis. During the physical model study four different measurements (wave parameters, layer thickness, velocity, weight of overtopping water) were taken. Methods for measure each of these parameters are described with instructions about the instruments. Calibration methods for each measuring devise are then explained. Chapter 4 presents the most important results from the model testing: primarily the reductions of mean overtopping rates due to different configurations. The influence of the crest drainage dike in reducing the overtopping volume per wave is explained and results from tests with different drainage options, overtopping layer thickness, and overtopping flow velocities for the crest drainage dike are given. Lastly, the results from selected tests on re-curve wall configurations are presented.

ComCoast (Combined Functions in Coastal Defence Zones) is an INTERREG IIIB project funded by the EU. ComCoast aims to develop and demonstrate innovative solutions for flood protection in coastal areas. In ComCoast, five countries from the North Sea Region are involved: Belgium, Denmark, The Netherlands, Germany, and the UK. In total, ten partners constitute the project consortium. Climate change cause already increasing physical load on coastal defence along the North Sea. Over the next decades, problems will arise through the need of adapting the existing coastal defence structures to modified conditions of coastal development, e.g. nature conservation areas, limited budgets, or changing social pretensions. New approaches emphasizing a gradual transition from sea to land are being explored in order to incorporate land use management with regard to the increasing pressure from population growth. These transitional areas will offer new opportunities both to the environment and to the people. In the ComCoast project, the need to develop new sustainable flood management strategies will be recognised in order to influence planners to anticipate future developments. Work Package 1 is one of the six Work Packages of the ComCoast project. Work Package 1 aims to identify feasible ComCoast areas along the southern North Sea. Work Package 2 explores new socio-economic evaluation methods for the ComCoast concept. The design and development of alternative embankments and strategies for coastal defence zones are worked out in Work Package 3. Work Package 4 deals with new and innovative participation strategies to involve stakeholders in the development process of ComCoast concepts. This technical report gives a short overview about the activities of Work Package 1 from Mai 2004 until Mai 2005.