foresight study: experimental facilities for study of …...foresight study: experimental facilities...

Foresight study: experimental facilities forstudy of climate change and adaptation

Deliverable 6.2

Status: Public

Version: Final

Date: 6 November, 2017

EC contract no 654110, HYDRALAB+

Deliverable 6.2 Representing climate change in physical models

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DOCUMENT INFORMATION

Title Foresight studies: experimental facilities for study of climate change andadaptation

EditorsContributors LNEC

Conceição Juana FortesMaria Teresa ReisAna MendonçaRute LemosMaria Graça NevesRui Capitão

DeltaresMindert de Vries

UPORTOFrancisco Taveira PintoPaulo Rosa Santos

UPCAgustín Sánchez-Arcilla

NOCPeter Thorne

UoHStuart J McLellandWietse Van de Lageweg

AALTOMikko Suominen

NTNUPierre-Yves HenryJochen Aberle

LUHMoritz Thom

HSVAKarl-Ulrich Evers

DHIBjörn ElsäßerAnne Lise Middelboe

Distribution Public


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Document Reference D6.2-Foresight_Studies_Experimental_Facilities_final.pdf

DOCUMENT HISTORY

Date Revision Prepared by Organisation Approved by Status

22/06/2017 106/04/2017 2 UPorto Draft02/05/2017 3 AM LNEC Draft09/08/2017 4 BJE DHI Draft20/08/2018 5 CJF/MTR/AM LNEC Draft01/10/2017 6 BJE DHI F.C. Hamer Final

ACKNOWLEDGEMENT

This project has received funding from the European Union's Horizon 2020 research and innovationprogramme under grant agreement No 654110, HYDRALAB+.

DISCLAIMER

This document reflects only the authors’ views and not those of the European Community. This workmay rely on data from sources external to the HYDRALAB project Consortium. Members of theConsortium do not accept liability for loss or damage suffered by any third party as a result of errorsor inaccuracies in such data. The information in this document is provided “as is” and no guaranteeor warranty is given that the information is fit for any particular purpose. The user thereof uses theinformation at its sole risk and neither the European Community nor any member of the HYDRALABConsortium is liable for any use that may be made of the information.


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ABSTRACT

The present report refers to Foresight studies, namely the identification of the need of new orupgraded experimental facilities and methods to study climate change scenarios for different typesof land-water interface (coasts, estuaries, rivers and arctic marginal zones).

KEY WORDS: Foresight studies, Climate change, Experimental Facilities, Equipment, Mesoscale


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ÍNDEX

Document Information ...................................................................................................................... 2

Document History ............................................................................................................................. 3

Acknowledgement............................................................................................................................. 3

Disclaimer ......................................................................................................................................... 3

Abstract ............................................................................................................................................ 4

1. Executive Summary ................................................................................................................... 7

2. Introduction .............................................................................................................................. 9

Context within HYDRALAB projects .................................................................................... 92.1.

The present HYDRALAB+ project ........................................................................................ 92.2.

Outcome from workshops ................................................................................................ 112.3.

3. The role of experimental facilities in evaluating risks and adaptation measures to climatechange ............................................................................................................................................ 14

meaning of adaptation to climate change ........................................................................ 143.1.

Coastal processes ............................................................................................................. 163.2.

Ice processes .................................................................................................................... 223.3.

Coasts and vegetation ...................................................................................................... 243.4.

3.4.1. Need for experimental facilities for full scale experiments (capable of investigationson the tripartite sediment-flow-vegetation) ............................................................................. 25

3.4.2. Need for replicate measurements ................................. Error! Bookmark not defined.

3.4.3. Need for environmental flumes ................................................................................ 27

3.4.4. The optimal hydraulic lab (a vision) ............................... Error! Bookmark not defined.

3.4.5. Need for field measurements ................................................................................... 28

Experiments and equipment needed ................................................................................ 283.5.

3.5.1. Need for investigations on plant health/behavioural integrity .................................. 28

3.5.2. Need for experiments on restoration of vegetation .................................................. 29

3.5.3. Need for experiments on green coastal protection potentials ................................... 29

3.5.4. Need for investigation on tipping points ................................................................... 30

3.5.5. Need for improved measuring techniques ................................................................ 31

Fluvial processes .............................................................................................................. 313.6.

4. Addressing Climate Change challenges: examples from the Hydralab+ experimental work....... 32

Research hosted at UPC ................................................................................................... 334.1.


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Research hosted at Deltares ............................................................................................. 334.2.

Research hosted at NOC ................................................................................................... 364.3.

Research hosted at LNEC .................................................................................................. 364.4.

Research hosted at FEUP/UPORTO ................................................................................... 374.5.

Research hosted at LUH ................................................................................................... 384.6.

Research hosted at DHI .................................................................................................... 404.7.

Research hosted at AALTO and HSVA ............................................................................... 414.8.

4.8.1. Experiments at AALTO .............................................................................................. 42

4.8.2. Experiments at HSVA ................................................................................................ 43

5. Recommendations ................................................................................................................... 60

6. References ............................................................................................................................... 63


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1. EXECUTIVE SUMMARY

The estimated rise of mean water level and increased storminess in the coming decades willprompt our societies to rethink our exploitation of the coastal regions worldwide. Thecoastal zone is heavily urbanized and important for industrial development and commerce.Facilities and structures, e.g. for protection of population and property along the watermargins, have been constructed based on design life expectations typically based onextrapolations of historical environmental conditions.

With the predicted climate change a large number of structures will need upgrading or insome cases relocation of facilities and population in order to reduce risk of damage and lossof life. The climatic evolution has and will also have an increasing impact on activities inoffshore regions. In this case, existing technologies have to be assessed focusing on theability to safely extract energy resources and on their impact on the environment withrespect to future conditions. In this regard also accident scenarios, related operations andconsequences require significant attention.

HYDRALAB+ considers it within its mission to:

a) Assess if the expected climate changes and adaptation measures will be properlyserved by the experimental tools available today;

b) Identify the new or alternative experimental tools and knowledge that will berequired to supplement other methodologies such as field observations, numericalmodels and statistical methods.

In this framework, the Foresight Studies, a networking activity of HYDRALAB+ project, arecarried in order to define the joint needs for morphological, ecological and structuralexperimental methods for climate adaptation in coastal regions and offshore. The foresightstudies in the previous HYDRALAB project defined the status of experimental technologiesand future needs at a general level for each of four areas: ecology, sediments, structuresand ice.

The objective of the new set of Foresight Studies is to consider the joint application ofmethodologies for various land-water interfaces (coasts, estuaries, rivers and arctic marginalzones) when exposed to climate changes.

In brief, the main objectives of the Foresight Studies within HYDRALAB+ are:

i) To define the needs for new or upgraded experimental facilities and methods bymapping of future risks caused by climate change for different types of land-waterinterface (coasts, estuaries, rivers and arctic marginal zones);


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ii) To identify experimental datasets relevant for testing and defining new approachesto adapt to climate change.

The first objective is strongly linked to the Joint Research Activities JRA1 and JRA2, ofHYDRALAB+ and is concerned with robustly modelling and representing the consequencesof climate change on coasts and rivers; while the second objective is clearly linked to JRA3and concerns relevant datasets for adaptation to climate change. Thus, two differentforesight studies are proposed based on these.

Results from the Foresight Studies are aimed towards researchers and policy makers with aparticular focus on how environmental hydraulics can contribute to improving the Europeanresponse to climate change through adaptation across a number of space and time scales.Specifically, the Foresight Studies will highlight areas of recent innovative developments anddirections for further research, describing advances made across HYDRALAB+ in deliveringthe next generation of facilities capability for addressing climate adaptation issues, whichwill deliver broad scientific and applied impact.

The present report refers to the first objective of the Foresight Studies, namely theidentification of new or upgraded experimental facilities and methods to study future riskscaused by climate change for different types of land-water interface (coasts, estuaries,rivers and arctic marginal zones), as well as the associated adaptation measures in differentregions of Europe.

In this document, section 2 introduces the context of Foresight Studies in HYDRALAB+, aswell as their objectives and methodology. Section 3 deals with risks and adaptationmeasures assessment in experimental facilities associated with climate change, focusing onthe common missing inputs to facilities, models, scenarios, equipment and methodologiesrequiring implementation and development. The experiments to be carried out by thepartners in order to study some of the identified risks and adaptation measures are alsodescribed. The report ends with the main conclusions of the work, and recommendation forthe future improvement and development of experimental facilities and methods.


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2. INTRODUCTION

CONTEXT WITHIN HYDRALAB PROJECTS2.1.

HYDRALAB is an advanced network of environmental hydraulic institutes in Europe, whichhas been effective in providing access to a suite of major and unique environmentalhydraulic facilities for a range of pure and applied scientists and engineers across the wholeEuropean scientific community. The structure of HYDRALAB projects are divided in threemain activities: Transnational Access (TA), Joint Research Activities (JRAs), NetworkingActivities (NAs).

Without exception, widespread appreciation and satisfaction has been expressed by all ofthe individuals and research groups supported by HYDRALAB to access these major andunique facilities (Transnational Access) and the work performed during access periods hasdelivered both substantive scientific advances and significant impact. Moreover, theHYDRALAB Joint Research Projects allowed the development of fundamental and appliedresearch between partners that worked together in a combined research effort to delivernew modelling guidelines for the entire international hydraulic community (e.g. thepublished monographs Users Guide to Physical Modelling and Users Guide to EcohydraulicModelling), as well as developing state-of-the-art instrumentation and innovativetechniques (e.g. for the measurement of sediment transport processes) that are at theforefront of hydraulic research.

HYDRALAB’s Networking Activities have been focussed on joint research activities, jointpublications and Advanced Workshops with external specialists. To ensure the broad impactof these activities, their results have been disseminated under the HYDRALAB banner at theleading international hydraulics and coastal engineering conferences and have led to thepublication of keynote foresight studies on environmental hydraulic modelling by theHYDRALAB team (e.g. Journal of Hydraulics Research).

THE PRESENT HYDRALAB+ PROJECT2.2.

As previously, the structure of HYDRALAB+ is divided in three main activities: TransnationalAccess, Joint Research Activities and Networking Activities.

The Transnational Access Activities enable international groups of researchers from acrossEurope to use our rare and unique experimental facilities that they normally do not haveaccess to, and thus to enhance the coherence of the European research community. Bymeans of the common User Selection Procedure optimal access is guaranteed for theseinternational research groups. Other objectives of HYDRALAB+ are to improve access to


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experimental data, by providing researchers with a database on experimental results, andbring young researchers and first-time users from across Europe to cutting-edgeexperimental research.

The Joint Research Activities focus on improving the capabilities of the experimentalfacilities, the research methods and instrumentation.

Networking Activities are pivotal to the impact on structuring hydraulic physical modelling inthe European Research Area and have been designed to maximize our impact whilstminimizing costs. Networking Activities are specifically designed to engage all potentialstakeholders and end-users of our research and data, including industrial researchers andpolicymakers. Networking Activities include dissemination events, fostering a culture of co-operation between the participants and the wider user community.

All these activities are connected. In fact, the work plan for HYDRALAB+ is based on aneffective management structure, such that the results from the Joint Research Activities andthe Networking Activities both lead to the improvement of Transnational Access services:JRAs 1 through 3 consider subjects related to robustly representing adaptations to climatechange and the flux of data that we can address within the duration of the project, whereasthe Foresight Studies in Networking Activity 5 consider the same subjects but with a timehorizon that is further into the future.

HYDRALAB+ stays connected to developments in fields that are not among the coreactivities through the inclusion of associated participants in Workshop Events and meetingscontributing to the strategy of HYDRALAB+. In particular, their participation in the ForesightStudies offers both the associated participants and HYDRALAB+, the opportunity toexchange experiences and points of view, to intensify future cooperation and to enlarge thegeographical spread of our network.

Following the example of previous HYDRALAB projects in disseminating good-practice toother infrastructure providers, guidelines will be produced for other physical modellingusers based on Critical Review studies (Work Packages WPs 8, 9 and 10) and ForesightPapers (WP 6). In the previous HYDRALAB project, the published guidelines have beendistributed to over 200 hydraulic laboratories throughout Europe and the world.

Two Foresight Studies are carried out: the first (Task 6.1 of WP 6) is linked to the JointResearch Activities JRA1 RECIPE (WP 8) and JRA2 COMPLEX (WP 9) and is concerned withrobustly modelling and representing the consequences of climate change on coasts andrivers; the second (Task 6.2 of WP 6) is linked to JRA3 FREE Data (WP 10) and concernsrelevant datasets for adaptation to climate change.


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The main objectives of the Foresight Studies are:

i) To define the needs for new or upgraded experimental facilities and methods tostudy future risks caused by climate change for different types of land-waterinterface (coasts, estuaries, rivers and arctic marginal zones), as well as theassociated adaptation measures in different regions of Europe;

ii) To identify experimental datasets relevant for testing and defining new approachesto adapt to climate change.

Foresight Studies will set the impact agenda for future structuring of hydraulic research inEurope and beyond, so that these facilities are best-prepared to tackle complex issuesregarding climate change adaptation.

OUTCOME FROM WORKSHOPS2.3.

The Networking Activities associated with Tasks 6.1 and 6.2 of WP 6 have included two workshops atthe HYDRALAB+ Partner and User Group meetings in Gdansk (September 10th, 2016) and Santander(May 19th, 2017), data gathering and information sharing via virtual meetings, and short descriptionsprovided by partners from which the present report originates.

In the Gdansk HYDRALAB+ meeting, at IBWPAN, a workshop related to the Foresight Studieswas held. In a first step, lists of the all the experimental facilities available in Hydralab+ werepresented and discussed. From this a short list with just the facilities selected for studyingthe different types of risks or adaptation measures to climate change was producedtogether with some example case studies. The short list, which is presented below, wasdiscussed with the partners:

· Stabilization of muddy coastlines - Deltares· Tagliamento River and natural flood management - UoH· Physical and biological cohesion of nearshore sediments - NOC· Changes and adaptation at the coast of Asturias - UCAN· Costa da Caparica study case – LNEC and UPORTO· Development of the Ocean Space Center, Trondheim - NTNU

In a second step, the participants of the workshop were divided into three thematic groups(Coastal, Fluvial, Coasts and Vegetation), each addressing all three questions below:

1. What are the common missing inputs to facilities/models/scenarios in the facilities orcase studies in relation to climate change and adaptation?


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2. What are the equipment and/or methodologies/procedures/approaches stillrequiring implementation or development (specific to climate change andadaptation)?

3. What larger scale datasets could be used to fill the above gaps and how can they bedownscaled? Can the relevant methodologies be prepared/delivered or publishedby/through HYDRALAB+?

At the end, there was an open discussion about the main ideas that emerged from theworkshop. A preliminary document on the results of the workshop discussions wasproduced. More detailed work is presented in this report concerning the answers to theabove questions 1 and 2.

A “Foresight Workshop: Contributions to deliverables 6.1 and 6.2” was held in the IHCantabria, Santander, on May 19, 2017. The progress on Task 6.1 was discussed togetherwith the potentials and challenges of crowdsourcing (Task 6.2).

During the Santander meeting, the audience was split into two groups: 15 participants for adetailed discussion and workshop on Task 6.1: ‘Adaptations to Climate Change –implementations and applications in physical laboratories – challenges and opportunities’;and 10 participants for a detailed discussion and workshop on Task 6.2: ‘Datasets for climatechange – crowdsourcing as an opportunity?’

In Task 6.1, the meeting was divided into two parts:

1st part - Each member was asked to write in Post-its the answers to the followingquestions:

· What are the experiments that should be addressed in the future to studyclimate change scenarios?

· What are the experiments that should be addressed to validate adaptationmeasures?

2nd part - Each member was asked to present to the rest of the group his/her answersto those questions.

At the end of parts 1 and 2, there was an open discussion about what should be the mainideas that come out from Task 6.1 workshop. Stuart McLelland proposed to present thoseideas at the meeting conclusion.

In Task 6.2 the working groups were split into two smaller groups to conduct abrainstorming exercise on the following four main questions:


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1. What are the areas in coastal and fluvial hydrology / climate change and adaptation,where data could be obtained via crowdsourcing?

2. What are the benefits of obtaining data via crowdsourcing?3. What are the issues of crowdsourcing in relation to the above identified datasets /

information?4. How could crowdsourcing be organized / facilitated? What equipment, tools are

needed?

The questions were discussed in sequence, with the first question being developed in a20-minute brainstorming session using Post-its. The ideas were grouped in two sections,which are observations/parameters and methods/tools. After this session, questions two tofour were addressed.

The topic of Task 6.2, while in parts relevant for this document, is not further discussed indetail here, but will be included in upcoming documentation related to this task.


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3. THE ROLE OF EXPERIMENTAL FACILITIES IN EVALUATING RISKS ANDADAPTATION MEASURES TO CLIMATE CHANGE

MEANING OF ADAPTATION TO CLIMATE CHANGE3.1.

Conflict is almost inevitable where continued development in areas interacting with coastal, fluvial,vegetation and ice processes requires stability, whilst natural processes involve change. As a result,development requires adaptation to natural processes. In terms of physical adaptations,conventional coastal adaptations can be split into ‘hard’ and ‘soft’ measures (Rumson, 2017; Linares,2012). Hard adaptation measures are generally regarded as semi-permanent installations on thecoast. Examples of these are seawalls, revetments, groynes, and breakwater sills. Soft adaptationmeasures include beach feeding (recharge), dune building, and ‘Managed Realignment’ (French,2001). Soft measures are deemed to be those designed to work with natural processes (Dodds,2009). “Hard” structure options, which date from 1800s (Davison, Nicholls & Leatherman, 1992),include the use or construction of dikes, levees, floodwalls, seawalls, revetments, bulkheads,groins, detached breakwaters, floodgates or tidal barriers, and saltwater intrusion barriers(Intergovernmental Panel of Climate Change, 1990). “Soft” structure options appear moresuitable in coping with sea level rise, as this approach potentially provides environmentally-friendly protection, is aesthetically pleasing, and can usually be implemented within areasonable budget (Black and Mead, 2001; Gómez-Pina et al., 2002; Khalil, 2008). Examples of“soft” structure options include: beach nourishment, dune restoration, “afforestation” orreforestation, and “soft” engineering approaches such as the construction of artificial reefs orseaweeds (Intergovernmental Panel of Climate Change, 1990; Intergovernmental Panel ofClimate Change, 1996). The benefit of using a “soft” structure option when compared with the“hard” counterpart (which only aims to protect coastal zones from sea level rise) is that itprovides opportunities to recover natural features (e.g. beach nourishment) and/or simulatesnatural growing environments (e.g. “artificial mangroves”). Some of these measures have beenapplied for several years (e.g. beach nourishment), whilst others are still in the testing process(e.g. “dissipators reefs”, “rotators reefs”).

In general, climate change will alter many important boundary conditions (e.g., rise of meanwater level, increased storminess, etc.) and the related development of measures foradaptation to these new boundary conditions brings new and important challenges to theexperimental facilities worldwide, in different scales and climate change related topics.

The European Commission’s White Paper (EU, 2009) on adapting to climate change presentsthe framework for adaptation measures and policies to reduce the European Union'svulnerability to the impacts of climate change. The White Paper highlights the need "topromote strategies which increase the resilience to climate change of health, property andthe productive functions of land, inter alia by improving the management of waterresources and ecosystems".


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The future water situation and developments in the water sector have been examined inEurope until 2050 by the ClimWatAdapt project in terms of vulnerability to water scarcity,droughts and floods. Downscaled climate change scenarios point to an increase of theoccurrence of droughts and floods. However, vulnerability to water scarcity is moredependent on socio-economic development (land use, water use) than on climate changeexposure.

Understanding the “adaptation to climate change” implies reviewing the Climate Changeeffects currently predicted in the coming decades, in order to anticipate our needs for newmethods, approaches and equipment in the (adapted) facilities and field. This is not onlyimportant for the Climate Change impacts on the environment but also on our society andits future needs.

Despite the above recommendations there is still a resistance in society trough a short-termview on adaptation, i.e., people think in terms of 1-2 years, not decades or centuries. In fact,people often want to keep things as they are without adapting to future scenarios (“not inmy backyard”-attitude); this leads for example to higher dikes, embankments, andalternative innovative solutions may be discarded.

Thus Foresight Studies are important to give direction and strategic overview in order toimprove the prediction of the efficiency of nature-based solutions that can contribute to thedevelopment of sustainable adaptive measures. We know a lot about uncertainties for“hard” engineering, but much less on the uncertainties for “soft” engineering. Reducing theuncertainties for “soft” solutions will provide valuable tools for decision makers andstakeholders.

Climate change impact on populations, infrastructure and ecosystems requires to plandecisions and that the right adaptive strategies are adopted and evaluated. This evaluationhinges on the availability and use of suitable datasets. For knowledge to be derived fromcoastal, fluvial or ice datasets, such data needs to be combined and analysed in an effectivemanner. Big Data involves powerful computer infrastructures, enabling storage, processingand real-time analysis of large volumes and varieties of data, in a fast and reliable manner(Rumson et al, 2017):

· In this connection, generating/handling large datasets will help reducing andcharacterising uncertainties, which may be dealt with by probabilistic approaches. Ingeneral, we need the same extent of knowledge on “hard” and “soft” solutions to be ableto pick the most appropriate, both from engineering and economic points of view. Inthose studies, transdisciplinary inputs are mandatory, so there is a need for an integratedapproach;


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· Develop time scaling techniques (in experiments) to simulate climate change processesand inspect whether proposed adaptive measures are confirmed/validated by laboratoryexperiments, including the quantification of uncertainties as mentioned above;

· Translate the uncertainties of the inputs (climate change model prediction) into physicalmodels and consequently into model outputs.

There is a growing understanding that Natural and Nature based solutions (NNBS) couldbecome part of effective and sustainable flood defence infrastructure of the 21st century.Having those issues in mind, in the next sub-chapter, Hydralab+ tries to make a seriousattempt to answer an important question:

What are the limitations of the existing facilities for addressing climate changescenarios and what experiments (and equipment) are needed?

Detail is given to the variables to be considered in the experiments, the forcing agents to besimulated, measuring equipment to be used in the experiments, experimental proceduresand methodologies for analysing the data in relation to coastal processes, ice, coasts andvegetation, and fluvial aspects. Two sub-goals/questions are assessed:

1. What are the common missing inputs for experiments, models and hence climatechange scenarios in the facilities or case studies in relation to climate change andadaptation?

2. What are the equipment and/or methodologies/procedures/approaches stillrequiring implementation or development (specific to climate change andadaptation)?

COASTAL PROCESSES3.2.

Worldwide, most experimental facilities are well prepared to simulate the typical forcingactions, related to waves, currents and ice (usually separately). It is known that traditionalwave basins and flumes present more conservative limits, in terms of wave steepness, thanthe ones found in the natural environment (for wind generated waves). In a climate changescenario, those forcing actions will be more intense, frequent and unsteady (e.g. seasonal orinter-annual variability, in relation to the slowly varying climate change) and dependent oneach other. Climate change effects are also expected to progressively lead to storms(hurricanes) with steeper waves (i.e., with a higher wave height to wave length ratio).Significant efforts have been made in recent years to properly generate tsunami waves, forwhich traditional wave generation machines do not provide a good solution. Thus, if climatechange effects are to be properly reproduced, efforts should be made in the future to installinnovative equipment in experimental facilities and provide them with novel techniques (e.g.


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new wave generation techniques) to allow the combined simulation of those extreme, steepand unsteady forcing actions and their measurement.

Since there is significant uncertainty in predicting the effects of climate change in thevariables driving the design of coastal and hydraulic structures (i.e., establishing the sealevel rise or predicting extreme events), the use of scenarios, estimating possible futurerealities, in the medium to long terms, is of paramount importance. Joint probabilityanalysis and probabilistic methods are also gaining relevance in the context of climatechange. This is transferable to the planning and operation of physical model studies. Sincethey are time consuming and expensive, the key question is how to properly selectrepresentative conditions to be included in the testing programme.

In addition, the relevance of reproducing sequences of extreme events over the structurelife span, including cumulative effects needs to be highlighted. Cumulative effects due tostorm sequences could lead to progressive failures, due to, for instance, armour instabilityand related overtopping of the structures. Therefore, a correct description of stormevolution is deemed fundamental for analysing the damage progression and its impact onwave overtopping. The focus on considering different sequences of extreme events (i.e., thechronology of the events) requires, in a first instance, the correct characterization of thoseevents (in terms of wave height, wave period, wave direction, sea level, among others) andtheir proper combination.

The intent of reproducing the chronology of events may lead to much larger test durationsand the need of including the tidal level variation in the long experimental tests (i.e., thetidal wave during wave attack). This requires the development of new systems to controlthe filling and the emptying process of experimental facilities (variable and controlled flowrate, since the velocity of the tidal level rise and fall is not constant). It also requires theanalysis of the effects in the operation of other equipment whose performance is influencedby the water level, namely the dynamic/active wave absorption systems which are based onreal time measurements of the water level in front of the wave-maker paddles, and even insome passive wave absorption systems sensitive to the water level changes.

In addition, if the consideration of long-term effects is of interest, the impact of marinegrowth and of concrete strength variation on, e.g., rubble mound block stability should beproperly analysed and the simulation of wind effects in the laboratory should also beimproved (e.g., mean and gusts wind effects).

The measurement of structure damage must preferably be obtained without draining andrefilling the flume or basin, which can take a considerable amount of time. Therefore, themeasurements should be able to be performed through the water surface. Oftenmechanical profilers are still the preferred measurement device but new methods


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(terrestrial laser scanners, underwater laser scanners and stereo photogrammetry) shouldbe used to scan the surface of coastal structures in order to obtain more precisemeasurements of damage (erosion). With these techniques, the surface can be obtainedwith millimetre resolution and sub- millimetre accuracy.

Another important question arises: how to scale time when looking at events with a longtime span? The challenge is how to define shorter test durations, still compatible with therequirements of current studies and projects, which may produce equivalent results.

It is also worth mentioning the issues related to down-scaling of materials such as, clay andfine sand and, consequently, their geotechnical characteristics, in order to have morerepresentative and reliable physical models. This is an important topic in relation to thestability of some structures, for example with respect to liquefaction and scouringphenomena depends.

Most studies in experimental facilities are done with fresh water, due to economic oroperational reasons. The characteristics of the water used in the experiments are not amajor concern, provided that it has been properly scaled, it has an acceptable level ofcleanliness and the desired measurements can be undertaken satisfactorily. In some caseshowever, it is important to consider both fresh and salt water, namely at the sea-riverinterface (estuaries), and the simulation of interaction between waves and currents.Experimental facilities with large areas are required for those studies.

A sustainable flood defence infrastructure can be based on Natural and Nature basedsolutions (NNBS). In many countries, possible implementations are currently being studied.One constraint of utilising these techniques is the uncertainty concerning the introductionof dynamic systems in flood defence solutions that need to deliver a guaranteed level ofsafety. Another is the availability and effectiveness of maintenance procedures. In themeantime, climate change and sea level rise are adding to this uncertainty. Not resolvingthese uncertainties will hamper the implementation of beneficial solutions for many uses.

A full scope of facilities is needed to both study landscape scale long term phenomena in thefield, with low and medium ranges of forcing, and smaller scale laboratory facilities that canstudy the rare but very significant extreme conditions in detail. An integration ofobservation methodologies and data facilities to bridge these scales and to provide atestbed for researchers will further enhance the pace of the research that is needed toimplement NNBS into the mainstream of engineering in the 21st century.

Many of the experiments needed to address the above issues will be ‘prototyping’experiments. This means that they are unique and large modifications are required to adaptto the specific experimental needs. At present, some of the required experiments are


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undertaken as lab-bench tests, where the testing space is small compared to the organismor process under investigation. Concern is that the constraints of such laboratoryexperiments influence the resulting response rather than the variable under investigation.However, the experiments are relatively cost effective and can be more readily tailored tothe specific needs. On the other hand there are a number of large scale facilities that allowsimulations for example with real sea water or wave generation at near full scale. These aremore expensive and do not allow several different setups, variables and configurations to betested due to the shear effort to modify them and the associated cost.

It appears that missing experimental facilities are on the interim scale or so called mesoscalefacilities, where waves and currents at near full scale can be implemented as eitheroscillatory flows of different periods and magnitudes or constant flows with relevantturbulence levels. These may facilitate replication either by setting up several similarexperiments in close succession or in parallel experiments of the same type runningsimultaneously. They would need to be operated as a close collaboration of transdisciplinaryscientists together to ensure that all relevant parameters are suitably represented, scaledand observed.

Based on the above issues and to summarize, the physical methodologies and experiments(laboratory and field) that should be addressed in the future to study climate changescenarios and validate adaptation measures include:

· Laboratory:o Test series to simulate extreme events (e.g. tsunamis, rogue -freak- waves,

earthquakes, very steep waves -high wind speed);o Long duration test series (reproducing the chronology/sequence of events, including

cumulative effects), incorporating the tidal level variation, and experimentsrepresenting greater peak power of storms, aiming to reach new predictingformulations of damage evolution and related overtopping in coastal structures(reduced lifetime?), taking into account the estimated environmental data for thefuture climate and incorporating recovery between events;

o Test series to analyse breakwater armour layer placement and long-term predictionof interaction between the armour units due to e.g. impact of marine growth and ofconcrete strength variation;

o Experiments on long-term behaviour of coastal structures induced by dynamiceffects;

o Experiments with currents and waves in a 2DH basin on 1:1 (e.g. working with mixedsediments and on interactions of biota-sediment on this scale; keeping such systemsin healthy conditions during the experimental period);


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o 2DV experiments: working with a Natural and Nature based solutions (NNBS) andwaves on extreme scale (many challenges remain: how to implement anexperimental design, how to handle turbidity and debris produced during such anexperiment, how to monitor effectively both the abiotic and biotic impacts duringthe experiment, how to effectively create a repeatable experiment with a variablebiological component that is harvested from the field or grown especially for thisexperiment?);

o 3D experiments on flooding cities / territories with human occupation andconstructions nearby the sea by downscaling a city mesh edification;

o Test series to map impacts of growing storminess on beaches (nonlinear interactionsbetween large energy fluxes and beach response); to study the performance ofbeach fills (reduced lifetime?) and role of secondary structures (e.g., groins,detached breakwaters, “soft” solutions, multipurpose structures); to analyse thecombination of coastal defence structures and sand dunes.

o Development of laboratories with many more computer-controlled nonlineardevices;

o Development of simulators to reproduce single phenomena in a controlled mannerin the field.

· Field:o Experiments to study landscape scale long-term and medium-term phenomena;o Flooding field and morphological risks in muddy estuarine and sandy bar island areas

under an uncertain climate change future;

In this framework, some equipment/measurements implementation/improvements arerequired to cope with climate change, both at the laboratory and the field, namely:

· Laboratory:o Wave generation software able to include new, less common, sea states;o Spatially distributed water surface measurements (surface elevation, velocity, etc.);o Forces/pressure analysis techniques taking into account the consequences of climate

change; force measurements on plants/ sediments/structures;o Instruments to measure water velocity in wave run-up and overtopping (water with

air bubbles) for different types of structure design (e.g. with wild life growing and/orwith innovative crest elements/crown-walls, to reduce run-up/overtopping);

o Measurements within porous media especially measurements of failure of porousmedia;

o High resolution morphological measurements rapidly and under water;o Measurements of processes around and above ripples;


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o Measurements of roll-back of barrier beaches;o New non-intrusive measuring techniques, such as terrestrial laser scanners and

stereo photogrammetry.· Field

o Landscape scale observation capability above and below water by improving the linkwith remote sensing (RS) observation platforms and their capability to deliver onhigh spatial and temporal resolution; especially, producing DEM’s and mappingbiological parameters (biomass, surface areas, height) from RS;

o Implementation mesoscale facilities and improvement of operational performancecapability of existing mobile equipment, controlling wave and current conditionswhile adapting to the tide; setting up

o Enhanced inexpensive monitoring platforms with smaller physical scales and betterdata transmission similar to IoT technology.

Smaller scale or miniaturised measurement equipment is necessary to facilitate capture ofdata in both laboratories and at full scale. In particular the cost and size of this equipmentshould be such that loss of equipment and or loss of data are not a major issue, simplybecause of the number of sensors deployed and thus the data coverage.

When dealing with climate change, as well as when concentrating our attention on thelimitations of existing facilities/equipment and the need for new/adaptedexperiments/methodologies, it is of paramount importance for physical coastal processessusceptible to climate change (e.g. coastal erosion; dune overwash; structure damageevolution and overtopping; tsunamis due to ice displacements) to be the target of continueddata gathering in order to update predicted climate conditions and consequently physicalmodelling setup and methodologies.

In this connection, a significant amount of metocean information is presently availablecompared to the scarcity observed in the past. However, additional efforts should be madeto develop techniques and tools to produce freely available datasets with higher resolution, .The sharing of meta-data over the semantic web and the transfer of data from remoteexperiments will also improve access to data. Global circulation and climatic models, as wellas buoy data, can be used to define local scenarios for testing. Coastal developmentsmonitored in the field under identified conditions can be used to validate long-termpredictions. Test results and experience in large scale/field can be useful for small modeltests and also for numerical approaches.


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ICE PROCESSES3.3.

The global warming has decreased the sea ice extent in the Arctic significantly. Because ofthe warming, the ice cover has retreated and the Arctic sea ice is more surrounded by openocean instead of land. The marginal ice zone (MIZ) is the transitional area between the openocean and the pack ice cover. It consists of individual ice floes of varying size, often formedby ocean waves penetrating into a solid ice field. Both winter navigation and offshorestructures may be subject to MIZ conditions at least during a part of the ice season.However, there is an insufficient understanding of the air-ice-ocean system to operateeffectively in this region. In particular, more open water in the Arctic has increased the waveintensity. As a consequence, wave propagation through the dynamically changing ice coversin the MIZ has become an important topic for all maritime operations in the Arctic (Eversand Reimer, 2015). Therefore, predicting the wave climate and its effect on a structure insuch an ice field is of practical importance. The waves affect the breakage of the ice cover,while the ice contributes to the attenuation and dissipation of waves (Montiel et al.,2016;Squire, 2007; Toffoli et al., 2015).

Despite the importance, limited amount of data is available from the wave propagation inthe MIZ. Field measurement (Wadhams et al. 1986, 1988) and remote sensing (Liu et al.,1991) data has been gathered, and laboratory experiments have been conducted (Newyearand Martin, 1997, 1999; Sakai and Hanai, 2002; Wang and Shen, 2010). However, fieldstudies, remote sensing, and laboratory studies have only scratched the surface of thecomplex wave-ice interaction problem. For a complete understanding necessary to guideArctic engineering in the MIZ, a systematic study is urgently needed.

Due to the climate change, the sea ice thickness has decreased and ice has become moremobile. Thinner and mobile ice will deform easier than thick ice. The ice can break due towaves and wind and form open water areas, or raft and form pressure ridges as a result ofcompression. The ice ridges is the most difficult ice condition the structure can encounter ina first-year ice condition as the thickness of the ridge (keel depth) can be several times thethickness of the surrounding level ice (Strub-Klein and Sudom, 2012). As the amount of landfast ice has retreated, the coastal structures are more likely to encounter these iceconditions than before.

Field data from the physical size of the ridges has been collected extensively (Strub-Kleinand Sudom, 2012) and the loads against structures were measured during field campaigns(see e.g. the EU projects LOLEIF and STRICE 1997-2003). However, the modelling of ridges inmodel scale basins contains a great uncertainty. The longer freezing time consolidates theridge making it more difficult for structures to resist while the newly formed ridges collapseeasier as the ice blocks are loose fragments. Thus, the scaling of ridges is problematic as it is


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uncertain how the properties of the ridge keel should be modelled, as the properties of thefull-scale ridges are also uncertain.

In addition to the ridges, the broken dynamic ice field will expose the structures more to thefloe ice fields. Due to the open water areas, the waves can form despite the damping effectof the ice. Thus, the structure will be exposed to the combined effect of the waves and icefloes. However, this combined effect has not been studied deeply in the past. Therefore,more research on this topic is needed.

As a result of diminishing land fast ice, the coastal erosion due to ice will increase. Ice canpile up against the shore forming ridges with a deep keel. When the ridges move away fromthe shore, they can smooth the shore (Barnes et al., 1988; Hiller and Roelse, 1995), createwallows (Reimnitz and Kempema, 1982), or create ice gouges, also called ice scouring(Barnes et al., 1988). However, existing ice basins focus mainly on the experiments with thestructures. In these experiments, the focus is on structure ice interaction and the shallowwater and land is modelled solid. Thus, the coastal erosion due to ice shaping the coast lineor sea bottom has not been studied by modelling the sediments in ice model scale basins.

As the ice is more mobile in the coastal areas, tests with ice in shallow water become moreimportant. When ice is piling against a structure in shallow water, the role of the shallowwater increases. The existing ice basins can model the shallow water conditions withremovable bottoms. However, in case of more structures are tested in shallow waters, apermanent liftable basin bottom could be more suitable. As mentioned above, the seabottom is rarely modelled as soft sediment. However, when thick ridges are pushed againsta structure, the soft bottom would have a different effect than solid one, if the ridge keelreaches the sea bed/basin.

In the near past, the Arctic has been frozen. Should the Arctic ice cover decrease, furtherand open water conditions start to dominate, and there is little knowledge on what kind ofsea conditions there will be. Thus, monitoring the developing conditions in the Arctic isimportant. Due to the large variety of possible outcomes and the associated uncertainties, itis not feasible to try to model all of them. The most critical scenarios should be identifiedand modelled.

Physical model experiments should also address the following aspects:

· Wave dispersion and attenuation in ice floe fields (represents MIZ);· Ice cover breakage due to waves;· Combined effect of waves and ice floes against structures;· The effect of sediments in shallow water structure-ice interaction experiments· Permafrost-flux interactions;


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· Shore erosion due to permafrost thawing processes;· Ice scouring due to ice ridges in shallow waters;· Sediment transport in ice;· Internal stresses in ice sheets;· Rivers blocked by ice jams (ice barriers);· Behaviour of structures frozen in an intact solid ice sheet that will be broken by waves;· Time scales:

o Impact of reduced ice cover on coastal erosion (e.g. sandy Baltic Sea beaches);o Modelling of ice breakup (ice jam flows) near river estuaries at the end of severe

winter and start of very warm spring.

Requirements and needs for new equipment and installations in the ice basins

· More advanced wave makers to produce larger variety of wave fields· More ice basins equipped with movable or permanent wave maker· More liftable basin bottoms· Possibility to use sediments in ice model basins

Requirements for field research

· The change of sea and ice conditions as a result of the thinning and retreating sea iceextent

· Wave-ice floes-structure interaction· Sediment transport by waves and ice· Ridge formation in coastline

A review on ice processes and short/long-term developments on related measurementequipment and facilities is presented in Sutherland & Evers (2013).

COASTS AND VEGETATION3.4.

At present, it is not feasible to take living organisms into most facilities because suitableenvironmental conditions such as light, water quality, temperature, etc., cannot besufficiently controlled or maintained to guarantee survival for the duration of theexperiment. On the other hand, facilities that allow the growth of organisms, such asmussels or eelgrass, are not sufficiently equipped to create wave or current action atrepresentative length and time scales in relation to the size and growth or reproductioncycles of the organisms.


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Another serious problem is that plants require time to grow. Changes in density andbiomechanics occurring on seasonally (winter die-off) as well as interannual scale result inphysical experiments which are unrealistically long. To solve this issue the use of surrogatesare investigated intensively in Hydralab+ but numerous issues still remain unresolved andorganism response to climate change is only one of these.

Further, the inherent variability of organism response to the same environmental conditionsrequires significant repeatability of the tests to satisfy statistical significance tests, which areused to distinguish random variability in organism response from causal response due tochanges in environmental variables.

Even though Hydralab+ mostly deals with experimental laboratories it is essential to alsoconduct field measurements for taking the next steps towards modelling the impacts ofclimate change (section 3.5).

In section 3.3 we propose a number of experiments that are needed to cope with thechallenges of climate change and are useful for an understanding of the coastal defenceabilities of vegetation.

3.4.1.Need for experimental facilities for full scale experiments (capable ofinvestigations on the tripartite sediment-flow-vegetation)

Investigating the effects of climate change on the tripartite sediment-flow-vegetation iseven more challenging, as a number of important feedback loops need consideration. Forexample, a number of knowledge gaps in sediment-flow-vegetation interactions have beenidentified by Thomas et al. (2014). Experiments can be used to isolate forcing actions andspecific processes. A good example is our limited understanding of sediment transportprocesses and how they may be affected by biological processes. Currently, the identifiedphysical modelling priorities are:

· Facilities to cope with muddy, mixed and cohesive sediments;· Non-optical measurement devices are needed to be able to measure in these muddy

environments;· Saline water experiments.

These modelling priorities for sediment transport processes are addressed in a number ofHYDRALAB+ experiments. Regarding the interactions between plants, sediments and flowwe will here discuss the role of seagrass (e.g. Zostera Marina also referred to as “eelgrass”)as an example for the complexity that physical experiments need to consider:

Seagrass meadows are important ecosystems as they form the basis for key ecosystemfunctions like nutrient cycling (McGlathery et al., 2007) providing shelter for fish (Van Katwijk


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et al., 2016), and are highly productive in terms of sequestration of carbon (Orth et al.,2006). Moreover, seagrass meadows have been identified as potential “green” coastalprotection structures; important in the context of climate change and its induced threats tocoastal shorelines (Paul et al., 2012; Ondiviela et al., 2014).

The presence of seagrass induces modifications to the flow field. For example, a field studyconducted by Hansen & Reidenbach (2012) revealed reduced near-bottom mean velocitiesby 70 to 90%, and wave heights from 45 to 70% compared to an adjacent un-vegetatedregion. Additionally, the induced modifications of the flow field and their effects onmorphodynamics (sediment stabilization and trapping) have strong implications for thesuccessful growth of seagrasses themselves, through the seagrass-sediment-light feedbackmechanism (SSL, as described by Adams et al., 2016), as well as their spatial organization(Fonseca et al., 2007; Van der Heide et al., 2010). As a result, the success of growth (i.e.shoot density, meadow height but also flexibility of leaves) again influences waveattenuation properties of the meadow (Paul & Amos, 2011; Paul et al., 2012).

According to Van der Heide et al. (2007) and Adams et al. (2016) the understanding of theseagrass-sediment-light (SSL) feedback is a key factor for explaining the success of seagrassgrowth. These studies identified a bi-stability between two ecosystem states. Whenseagrass meadows are present and their biomechanics, as well as dimensions, satisfy certainconditions (depending on leaf flexibility, shoot density, meadow height, etc.) they canreduce near-bed current velocities and dissipate wave energy. As a consequence, theturbidity in the water column is reduced, which promotes the light availability to- andphotosynthesis of the seagrass to induce further growth (a conceptual model is illustrated inFigure 1 Left). On the contrary, when seagrass is absent or seagrass meadows are notmeeting the requirements, turbidity might impede further growth or even lead to losses.Seagrass meadows, therefore actively modify and are modified by their environment at thesame time, possibly to result in unique spatial arrangements, as for example the regularlyinterspaced banded patterns, presented in Figure 1 (Right), as reported by Van der Heide etal.. (2010) and Fonseca et al.. (2007).


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Figure 1 Left: “Simplest conceptual model of the SSL feedback, consisting of seven linked processes. Positiveand negative causal links are indicated with plus (1) and minus signs (2), respectively. For example, in process(i) an increase in suspended sediment will cause a decrease in light at the canopy (negative causal link); inprocess (ii) an increase in light at the canopy will cause an increase in seagrass presence (positive causal link)”(from Adams et al., 2016 ). Right: Three examples of spatial organization showing seagrass growth in regularlyinterspaced banded patterns (A and B from Van der Heide et al., 2010; C from Fonseca et al., 2007).

While much of our current knowledge on the interactions between seagrass and sedimentdynamics is from field studies (e.g. Hansen & Reidenbach, 2012, 2013), far less research hasbeen devoted to physical experiments at the full scale (i.e. 1:1), where the sedimenttransport processes of sand can be studied without scaling effects. However, includingsediment in physical models is mandatory if we want to understand the response ofseagrass to a changing climate and the resulting ability of intact seagrass meadows as greencoastal protection interventions. Another important aspect of full scale experiments onvegetation is that it is currently at least difficult to find appropriate surrogates for certainplants which can be scaled down. Consequently, the use of real plants in full scaleexperiments should be prioritized which however requires the plants to be in a healthy state(i.e. “close to nature” environmental conditions) when the experiments are run.

3.4.2.Need for environmental flumesAnother aspect is that in some studies (with biological/organic materials/elements, forinstance), the characteristics of the water (temperature, salinity and other bio-chemicalproperties) might have to be properly reproduced, as well as the light conditions of naturalenvironments.

· Flume with controlled conditions regarding oxygen, temperature, light, etc., forexperiments with real plants;


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· Use of salt water in the experiments with real vegetation.

3.4.3.Need for field measurements

When studying areas of significant geographic extend, simulation of the hydrodynamics isnot feasible in a lab experiment on a reasonable scale. Most parameters that will impact thestudy areas also vary significantly in terms of spatial scale from metres (water depth) tohundreds of kilometres, as well as temporarily from hours (wave activity, light penetration,turbidity) to decades (nutrient levels, storm surges). Thus, it is only realistic to simulate theprocesses in numerical models that capture both spatial and temporal scales in a suitablematter. However, the numerical models have two major limitations at present, which needto be overcome for a successful representation of the relevant processes. These are:

· The calibration or parameterisation of a range of processes such as (and not limitedto) sedimentation and resuspension processes, magnitude of flow attenuation dueto the vegetation, interaction with other fauna or flora and many others;

· Coupling of hydrodynamic and biological processes in both directions, such as thedecrease of flow because of the growth of the vegetation, change in growth becauseof the sedimentation, the increase/decrease in light penetration because of a changein turbidity, caused by the changes in growth. At present, some of these processesare defined ‘a priori’ or only ‘one way’ coupled in the numerical models.

As a result of the above constraints and requirements there is a range of differentexperiments needed, some of which are only going to be possible through combinations ofspecific in-situ experiments and measurement campaigns, and controlled laboratoryexperiments. The complexity of the properties of the vegetation for example limits the useof surrogates. Ideally, parts of the environment should be taken into the lab to simulatespecific effects or interactions.

· How well can the findings of the vegetation experiments explain the spatialorganization that is observed in the field (e.g. from Rødsand lagoon; see Section 4.7)

· Need for improved data flux (field-lab/field-numerical and lab-numerical, seedeliverable 10.4 under Hydralab+).

EXPERIMENTS AND EQUIPMENT NEEDED3.5.

3.5.1. Need for investigations on plant health/behavioural integrityWhen “soft” solutions including vegetation (or other biota) are to be tested, the problem ofcorrectly reproducing the vegetation arises. An important distinction needs to be made inthe context of behavioural integrity of plants: it is okay for short-term (hours – days)


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experiments but unknown for the longer-term (> multiple days) experimental modelling.Frequent question are as follows:

· How to make organic matter to grow up in the experimental facility fast enough? Is itacceptable to transplant vegetation produced nearby (e.g., in a greenhouse) or it is abetter option to collect the plants in their natural environment and then transplantingthem? Is the fixation of the vegetation roots to the substrate in the experimental facilityequivalent to the prototype conditions? Which methods and techniques are available tomake a complete assessment of that?

· Experiments to study the impact of environmental influences on biomechanics thatcannot be properly studied in our facilities today: light, climate, temperature, salinity,and acidification.

3.5.2.Need for experiments on restoration of vegetation· (Re-)establishment of seagrass, saltmarshes;· In general it is presently understood that an improvement in water quality, reduction in

eutrophication and better control on dredging and trawling activities, resulting inreduced turbidity and thus higher biomass production of the vegetation, should yield arecovery of the eelgrass. However, mechanisms are clearly not well understood, aseelgrass in Danish coastal waters, for example, has not recovered even though nutrientloadings have been significantly reduced.

· Measures include the establishment of protected areas to limit anthropogenic activitysuch as dredging in relevant areas. The crucial interactions between biota and thephysical environment suggest that solutions that take into account interactions willbenefit the biological, as well as the geo-physical environments. However, as theinteraction of the biogenic effects, such as the reduction in flow and attenuation of waveaction as a result of the eelgrass, is not fully understood and quantifiable, it is todaydifficult to assess longer term effects and how these are best mitigated.

3.5.3.Need for experiments on green coastal protection potentials· Implementation of adaptive and multipurpose structures for coastal protection (“New”

materials, alternatives for clay);· “Soft” protection coastal structures, such as vegetation surrogates (artificial, plastic,

plants), scaled in time and space; dike covers (natural vegetation vs cultivated grass);influence of plants on coastal erosion;

· Test different types of structures design in order to enable wild life growing to reducerun-up and overtopping;

· Landslide phenomena in dunes;· Role of low crested breakwaters as support for sustainable seagrass beds.


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· Mega nourishments, sediment pathways;· 3D testing dune erosion protection using different types of vegetation (e.g. cactus or

tropical plants);· Waves and vegetation:

o Identify species that offer attenuation of waves;o Analyse the wave height reduction due to the spatial arrangement of seagrass;o Study artificial/real vegetation growth strategy against a sequence of storms;

· Thresholds for change resulting from growth/decline in vegetation (driven by climatechange);

· Experiments and methodology to focus on the influence of vegetation on erosion; to besure that the vegetation exists for the long(er) term; probabilistic approach might help toindicate necessary margins;

· Role of artificially planted vegetation on rehabilitated dunes (perhaps selection of moredurable plants without affecting local biodiversity);

3.5.4.Need for investigation on tipping pointsClimate change modelling progress has been undertaking, giving an estimate of the changeof most of the water and biological parameters (measurements of water temperature,salinity, oxygen levels, as well as other biological parameters such as turbidity, PAR levels,nutrient levels), except in relation with the changes in the distribution of the eelgrass, themussels, and associated living organisms. One of the high-risk events is for example theirreversible eradication of the eelgrass and the associated habitat structure because ofchanging environmental conditions. These could be due to:

· Increase in temperature resulting in longer periods with water temperatures wellabove optimum for growth (app. 15°), reducing growth and habitat suitability;

· Change in grazing organisms due to the introduction of new species or changingwater temperatures increasing the grazing rates of existing species;

· Increased wave activity and thus higher physical exposure of the habitats, as well asmore suspended sediment in the water column reducing light availability for growth;or

· Erosion on adjacent coastlines or sounds changing sedimentation patterns.· How does the spatial arrangement of seagrass meadows impact the SSL feedback to

promote further growth and thereby ensuring coastal defence properties, as well asecosystem services?

· What are the consequences of climate change on the presence and properties ofseagrass meadows?


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Key question in this is if an organism or in fact an entire habitat structure will seize to exist,reaching a point in coastal processes, where an irreversible momentum is reached, oftentermed the tipping point. In general nature has been found to be very adaptable but theactual point at which a significant shift in habitat structure occurs is for many temperatehabitats not known.

3.5.5.Need for improved measuring techniquesIn relation to measurement techniques a wide range of in-situ and lab scale techniques areavailable. Some of these techniques need to be adapted to new environments, remotelogging or miniaturised to improve suability for the respective experiments.

Accuracy and resolution of measuring equipment has increased very significantly in the lastdecades in all domains of hydraulic research. The rising interest of the scientific communityon climate change adaptive measures and eco-hydraulics introduced new challenges toexperimental methods and techniques namely those concerning the measurement of thevariables of interest in bottoms with bed forms and vegetation, especially in the closevicinity of the bottom.

FLUVIAL PROCESSES3.6.

In fluvial processes, a better knowledge on the uncertainties of the involved inputs (climatechange model prediction) is required and consequently of model outputs. Development ofprobabilistic approaches (generating/handling large datasets) would help reducing andcharacterising uncertainties. Methodologies to address the unsteadiness of the processesare also required. Moreover, it is mandatory to improve the prediction of the efficiency ofnature-based solutions, which would contribute to the development of sustainable adaptivemeasures and provide valuable tools for decision makers and stakeholders.

Transdisciplinary inputs are generally missing, so there is the need for an integratedapproach. For example, in some fluvial/coastal environments, the study of climate changeeffects and adaptive measures might involve the unusual (until now) combination of somephysical agents. When dealing with the modelling of soft cliffs, the reproduction of extremerain fall events may be of importance. This leads to the need of modelling the rain intensityand its spatial distribution in time and it requires solving some new scaling effects (e.g.,tension effect in water drops).

Before performing additional experimental work in the field or in the laboratory, it isimportant to learn how to search for the right/best dataset already existing to answer aquestion. Innovation-based on a better knowledge/understanding of theory and physics offluvial processes is essential, so that full use of existing or new datasets from novel


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instruments can be made, i.e. it is important to find new knowledge-based methods toextract as much information from a dataset as possible. For example: a laser scan of a riverbed may directly be used to derive the hydraulic roughness from the information of thebathymetry (Aberle & Smart, 2003, Coleman et al. 2011; Flack & Schultz, 2014); thedetermination of sediment transport rates in the field may be done through monitoring ofbed elevations with an ultrasonic sensor; etc. (e.g., Aberle et al. 2012, Muste et al. 2016 andreferences therein).

Most experimental studies are done with fresh water. In some cases, it will be important toconsider both fresh and salt water, namely at the sea-river interface. Climate change effects(e.g. mean sea level rise and drought periods), are expected to lead to salt water intrusionfurther upstream in rivers.

Relating to river flow processes, long-term river flume experiments should be conducted tocapture all processes that might be influenced by climate change. The effects of changingpatterns of flows should be considered, i.e., the existence of more high flow events andpossible low flow periods due to climate change (warmer/wetter winters). It is important aswell to analyse river flow and groundwater flow interactions, e.g. groundwater flow behindwater defences. The interaction between the flow and biofilm should also be studied, e.g.by analysing biofilm grown in fluctuating flow conditions versus biofilm grown in constantflow conditions. To study the interaction between the flow and vegetation, manufacturingof surrogate vegetation, both in quantity and with the correct biomechanics, is essential.

Experiments on river embankment failure and identification of failure mechanisms are alsoimportant. The role of water table/moisture level on river flooding, including embankmentfailure, must be analysed, as well as increasing sediments in river banks, their impacts ongrowing vegetation and animal impacts on sediment erosion/deposition.

Multiscale experiments (incorporating the complexity of full bed, soil, vegetation and fauna)and pilot studies in the field (involving live flora and fauna) are useful for small model testsand for numerical modelling, and may include the analysis of flood river effects on cars,trees, infrastructure, etc.

4. ADDRESSING CLIMATE CHANGE CHALLENGES: EXAMPLES FROM THEHYDRALAB+ EXPERIMENTAL WORK

The experiments proposed by the partners in order to study some of the risks andadaptation measures assessed in section 3 are identified. A brief description of themethodologies/procedures/approaches carried out in those experiments is presented below.


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See also Hofland et al. (2017), Marzeddu et al. (2017), Mendonça et al. (2017) and Silva et al.(2017) for detailed updated information.

RESEARCH HOSTED AT UPC4.1.

Regarding the experiments to validate the adaptation measures, UPC is going to performtwo different tests within the COMPLEX JRA. The first dataset will be related to the use ofgeobags as a protection measure at the toe of a dune. The main objective of theexperiments is to evaluate the geobags performance with respect to coastal protectionwhile the geobags get exposed during storm situations. The study will focus on the sedimenttransport patterns analysis in the surf and swash zone. The changes in the sedimenttransport will be assessed by performing the same study cases without the geobags with thesame beach and dune profile. The experiments will include different wave conditions underwhich the geobags will be exposed along several erosive conditions. The second datasetplanned within UPC involves an emerged nourishment test. This test is yet to be planned(dimension, location and waves to be tested).

It is expected that both datasets will help the planning of coastal protection measurementsand improve the know-how to better adapt to climate change scenarios and solutions.

RESEARCH HOSTED AT DELTARES4.2.

Collectively, for the purpose of further understanding in the field of flooding andmorphological risks in muddy estuarine and sandy bar island areas under an uncertainclimate change future, and for understanding the effectiveness of the use of ecosystemservices for maintaining flood safety, the experiments proposed in this document willexamine the following parameters:

· Temperature forcing and energy forcing (currents, waves, wave groupings andreflections, frequencies and intensities);

· Water level, water depth, inundation frequency;· Bed formations, roughness, material composition and bed composition in relation to

sediment strength and erodibility parameters;· Changes in sediment transport mechanisms in relation to variable short-term forcing

and long-term trends;· Presence of stabilizing species or species assemblages (reefs);· Vegetation and reef characteristics, vegetation and reef relation to sediment

stability;· Resilience of species and communities, ecotopes (landscape);


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· Communities, assemblages, landscape and associated natural values and flood riskreduction capacity;

· Impact of maintenance interventions on species and landscape.

Forcing agents in the proposed experiments include: water level; energy, expressed aswaves and surges; and temperature. The ranges of values predicted to occur as a result ofthe effects of global climate change should be considered. Specifically, the relevant forcingagents can be described as follows:

· Longer-term processes with generally lower energy level and known butuncontrolled forcings such as wind, waves, tides, and currents, will be examined inthe field. A mobile field wave generator will be used during certain field experimentsto examine the response of nature-based flood defences to controlled forcing undernatural conditions.

· In both a basin and a flume, short term processes that possess higher energy levelswill be investigated.

· Two dimensional horizontal (2D-H) experiments in a basin will employ knownforcings that will be generated with wave generators, water level and currents,which will mostly be scaled down, but the experiment will also be unscaled forsaltmarshes and reef experiments with small amplitude short-waves. In unscaledexperiments we can work with mixed sediments and study along shore and onshoretransports.

· Two dimensional vertical (2D-V) experiments in a wave flume with tidal forcing, willinvolve unscaled work that employs known forcings, and will be used to investigatesituations involving mixed sediments, sediment-vegetation interaction, and wave–vegetation interaction at realistic scales.

In these experiments the following measurement equipment will be employed:

· Water level and wave pressure sensors, 2D imagery of wave fields, ADCP for 3Dvelocity fields, 1D and 2D laser scanning and stereoscopic imagery of bed features,sampling equipment for establishing bed composition and stability parameters (e.g.,sediment size fractions, organic/inorganic components, porosity, etc.);

· Quantification of species and species assemblages’ presence by 2D-3D imaging,biomass and vitality parameters (this could be remotely sensed and/or measured bytaking samples). On field/landscape scale this work can be augmented by usingdrones, airborne or spaceborne sensors;

· Differential Global Positioning System (DGPS), Optical Back Scatter (OBS) and LaserIn-Situ Scattering and Transmissometry (LISST) for turbidity and suspended sedimenttransport, SED-sensors or sediment traps will be used to establish short term


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sediment transport rates, longer term and larger scale trends can be captured byairborne LIDAR and other remote sensing techniques.

The experimental procedures proposed are as follows:

· Field –Short term (hours-days-months): Pilot scale experiments with floating wavegenerators to simulate the effect of short-term high-intensity waves (storm events) onnatural and nature based defences and morphological changes (mudflats, reefs andsaltmarshes);

· Field –Medium term (2-5 year): i) Pilot scale experiments on placing and nourishingstrategies of sand, mud and mixtures on foreshores, intertidal areas and saltmarshes forthe purpose of investigating impacts on species composition, resiliency of species andassemblages and sediment fluxes and characteristics; ii) Investigating the scaleinteractions between local processes and landscape scale phenomena and evolution;

· Laboratory 2D-H – Short term: i) On mesocosm scale (tens of meters) study thesediment (de)stabilizing effects of reefs, vegetation and combinations under controlledconditions simulating high frequency events in an unscaled experiment. The experimentwill be conducted for hours to days and will use material harvested from the field. It willdeliver insights in behaviour of sediment mixtures in the presence of biota. This setupwill allow investigators to replicate conditions and carefully control experimentalvariables; ii) Study of the wave attenuation effects of reefs and vegetation andinteraction of waves, currents and the structures themselves. Both crosshore andlongshore aspects will be studied under different installation configurations;

· Laboratory 2D-H – Medium term: On mesocosm scale (tens of meters) study longer-term effects of sedimentation and erosion. These experiments will take place in openair, in close vicinity of the field site. This will enable us to experiment in a system withcontrolled forcings but uncontrolled natural conditions that will enable investigationsinto the living components of the mesocosms;

· Laboratory 2D-V -Short term: True scale experiment to examine the attenuationproperties of species and assemblages under extreme wave conditions, varying waterlevels and exposure times and frequencies;

· Laboratory 2D-V- Medium term: True scale experiments to examine the resiliency ofthese structures under extreme forcing, with a focus on intensities and frequencies thatsimulate changing weather patterns brought on by climate change.

The methodologies for analysing the data will follow protocols and standard practices thatare adapted from previous projects such as FP7 FAST, and Dutch practices for monitoringand analysing physical, chemical and biological system properties. These methodologies aredescribed in the project reports of Nature Coast, BE-SAFE, MOS2, and others.


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RESEARCH HOSTED AT NOC4.3.

In most infrastructures presently available there is often some reluctance to put cohesivesediments into the facilities because of the impact on the facilities engineering and postexperiment clean up problems. Further, there is no largescale facility that presently allowsthe matrix variation of hydrodynamics, temperature, salinity, light levels and sediment type.Therefore to comprehensively study the stability of nearshore sediments due to impacts onphysical and biological cohesion, a facility would be required that attends to a broader rangeof parameter variables than generally available in present day particular infrastructures.

Some of the above will be investigated in COMPLEX and RECIPE in differing facilities to tryand address cohesion and nearshore stability issues.

RESEARCH HOSTED AT LNEC4.4.

The identified needs for LNEC’s experiments and test methodologies include:

· Storm event sequences, considering cumulative effects;· Sea level rise;· New and non-intrusive measuring techniques.

LNEC’s experimental work to address the above issues considers 2D damage measured by astereo photogrammetry setup and overtopping tests for a rock armour slope, with fourdifferent approaches to represent storms: a standard cumulative storm build-up (withincreasing wave heights) with increasing water level; a standard cumulative storm build-upwith a constant water level; a constant wave period; and a standard storm build-up, with aconstant water level and with rebuilding.

The relationship between different damage parameters is examined for a number of testseries. The results are compared with high-resolution damage data resulting from 3Dphysical model tests at FEUP. Additionally, comparison is performed of measured (physicalmodel tests) and predicted (empirical formulae) mean overtopping discharges andindividual overtopping volumes.


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Figure 2 Left: Model setup in LNEC flume. Right: Model setup in FEUP basin.

RESEARCH HOSTED AT FEUP/UPORTO4.5.

The experimental tests carried out at the multidirectional wave basin of FEUP/UPORTOwere done in collaboration with Deltares and LNEC, and included 3D damage tests on arubble-mound breakwater with a rocky armour layer, Figure 3, to study the damageprogression in the trunk (front and rear slopes) and roundhead of the structure, consideringthe effect of sea level rise. The experiments also included overtopping measurements.

Figure 3 Model setup in FEUP/UPORTO wave basin. Left: plan view, right: damage measurement.

The work was designed to allow obtaining high-resolution data on damage progression inthe armour layer of rubble-mound structures using high resolution and non-intrusivemeasuring techniques (Hofland et al., 2011) and was carried out on a geometric scale of1:35 to ensure reduced scale effects. A wide breakwater trunk was used for statisticalreasons and to reduce uncertainty in the analysis of the results.

In each test series, from test to test, the significant wave height was increased from 60% to120% of the design wave height (the peak wave periods was also increased to maintain thelocal wave steepness constant). In some test series, damage on the rubble-mound structurewas cumulative, but in the other cases the structure was rebuilt after each test run. The

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Rear slope damageevaluation area

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main conclusions are (Hofland et al., 2017): significant scatter was also observed in theresult of tests carried out under identical conditions; for the higher water level (with SLR)and equal wave height, less damage was observed in the structure; the damage hole wasdeeper around the water line and that its size increased with the significant wave height;clear differences between “cumulative damage” and “rebuilding” test series were observed;the damage to the trunk is lower for short-crested waves. In addition, the design values forthe damage depth E2D proposed by Hofland et al. (2011)

foresight study: experimental facilities for study of …...foresight study: experimental facilities...

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