Delft University of Technology

The Sand Motor: A Nature-Based Response to Climate Change Findings and Reflections of the Interdisciplinary Research Program NatureCoast Luijendijk, Arjen; van Oudenhoven, Alexander

Publication date 2019 Document Version Final published version Citation (APA) Luijendijk, A., & van Oudenhoven, A. (Eds.) (2019). The Sand Motor: A Nature-Based Response to Climate Change: Findings and Reflections of the Interdisciplinary Research Program NatureCoast. Delft University Publishers. Important note To cite this publication, please use the final published version (if applicable). Please check the document version above.

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This work is downloaded from Delft University of Technology. For technical reasons the number of authors shown on this cover page is limited to a maximum of 10. RESEARCH PROGRAM NATURECOAST – CLIMATETO CHANGE RESPONSE NATURE-BASED A MOTOR: SAND THE Contributors Aarninkhof, Stefan 198 THE SAND MOTOR: A NATURE-BASED RESPONSE Aerts, Rien 128 Allewijn, Roeland 190 Aukes, Ewert 12, 28, 30, 38 TO CLIMATE CHANGE Bacon, Patrick 154 Baptist, Martin 130 Bierkens, Marc 176 FINDINGS AND REFLECTIONS OF THE INTERDISCIPLINARY Bodegom, Peter van 148 Bontje, Lotte 34, 168 Boer, Cor de 6 RESEARCH PROGRAM NATURECOAST Bressers, Hans 42 Bridges, Todd 196 EDITED BY Dwarshuis, Lenie 22 Egmond, Emily van 122 Arjen Luijendijk Flikweert, Jaap 180 Alexander van Oudenhoven Gelder, Carola van 24 Heerema, Jacqueline 152 Heijer, Kees den 150 Arjen Luijendijk (right) was active in the NatureCoast Herman, Peter 126 program as a postdoctoral researcher at Delft Hoonhout, Bas 100 University of Technology from the start in 2013 Huisman, Bas 62 until the end in 2018. He focused on setting up the Huizer, Sebastian 66 interaction between the PhD researchers and Kleij, Hans 46 end-users, as well as integrating the research findings. Koningsveld, Mark van 194 He worked on developing integrated model forecasts

Kothuis, Baukje interviews (eds) Oudenhoven Van and Luijendijk and developed the world’s first global beach erosion Kwadijk, Jaap 188 map. He is currently working as a Specialist at Linnartz, Leo 132 Deltares and as a researcher at the Delft University Luijendijk, Arjen 12, 50, 52, 84, 86, 138, 142, of Technology on predicting the future behavior of 146, 158, 160, 164, 166, 170, 172, 174, 184 the world’s beaches. Moons, Simeon 114 Mulder, Jan 78 Alexander van Oudenhoven (left) was active in the Nieboer, Henk 186 NatureCoast program as postdoctoral researcher at Nolet, Corjan 96 Leiden University between 2015 and 2018. He focused Oude Essink, Gu 176 on integrating the program’s scientific findings, Oudenhoven, Alexander van 12, 112, 136, thereby looking at the potential benefits that nature- 138, 142, 146, 164, 168, 170, 184 inclusive coastal management can generate and how Ovink, Henk 2 these are perceived. He is currently working as an Pit, Iris 70 assistant professor at the Institute of Environmental Post, Marjolein 118 Sciences at Leiden University, working on the Price, Timothy 74 interface between biodiversity, ecosystem services Puglia, Michel 80 and societies’ quality of life. In the spring of 2018, he Puijenbroek, Marinka van 92 NatureCoast is the largest research program that focused on the The NatureCoast program was carried out by a consortium became Co-Editor in Chief of Ecosystems and People, Radermacher, Max 54 Sand Motor, a large sandy peninsula, constructed in 2011 on the Dutch of knowledge institutesand universities, and the research was an interdisciplinary open access scientific journal. Ruessink, Gerben 76 North Sea coast near The Hague. This unprecedented pilot project conducted in cooperation with end-users from private companies, Rutten, Jantien 58 involved placing 21.5 million m3 of sand on and in front of the beach research institutes and governmental organizations. The Dutch Schipper, Matthieu de proof read with the aim that it would spread along the coast. The Sand Motor Technology Foundation (NWO-TTW) provided the largest share Slinger, Jill 192 is a unique beach nourishment due to its size, the design philosophy of the project funds. The research in NatureCoast focused on six Stive, Marcel 4 behind it, and its multifunctionality. It combines the primary function themes: coastal safety, dune formation, marine ecology, terrestrial Thiel de Vries, Jaap van 160, 178 of coastal protection with the creation of a new natural landscape ecology, hydrology and geochemistry, and governance. This book Valk, Bert van der 108 that also provides new leisure opportunities. From the outset, presents countless facets of the Sand Motor, but we also hope it Vertegaal, Kees 106 “learning by doing” has been a crucial part of the project and demonstrates the scientific merits of interdisciplinary research and Vikolainen, Vera 166 NatureCoast was an integral part of this. Because of its innovations, how, ultimately, societies can benefit from it. Waterman, Ronald 46 the Sand Motor has triggered considerable political and scientific Wijnberg, Kathelijne 104 interest from all over the world. Broad research consortia were NUR 950 Williams, Isaac 88 formed to conduct interdisciplinary research on the Sand Motor. ISBN 978 94 6384-021-7 THE SAND MOTOR: A NATURE-BASED RESPONSE TO CLIMATE CHANGE

FINDINGS AND REFLECTIONS OF THE INTERDISCIPLINARY RESEARCH PROGRAM NATURECOAST

Edited by

Arjen Luijendijk Alexander van Oudenhoven

DELFT UNIVERSITY PUBLISHERS 2019 Henk Ovink MITIGATE TO ADAPT AND BUILD WITH NATURE, 1.5 DEGREES IS MORE THAN ENOUGH!

PREFACE

Henk Ovink is Special Envoy for International Water Affairs and With Henk Nieboer from EcoShape I wrote about nature-based Sherpa to the UN/WB High Level Panel on Water. solutions and their critical capacity to answer to these challenges: “Nature-based solutions require a comprehensive approach to engineering. They address societal needs for flood protection, The in October 2018 presented report "Global Warming of 1.5 degrees" infrastructure and food production while providing additional of the Intergovernmental Platform on Climate Change (IPCC) is very benefits in increased biodiversity, CO2 sequestration, recreational clear: we are on track towards an inhabitable planet. Limiting it to and economic values. Furthermore, nature-based solutions are 1.5 degrees will make the world more sustainable and more equitable. adaptable to changing circumstances, often cost effective and more But it will not be easy to keep us all within that threshold, since we are impactful than our traditional solutions." heading towards a much larger than 2.0 degrees increase. This will demand systems’ changes on all levels. Climate change impacts are The Sand Motor is such a nature-based solution par excellence. already here. We lose millions of people and billions of dollars. Every year It required innovative governance, plus institutional, business is record-breaking with more intense disasters, casualties, damages and and finance models and frameworks. It also required an inclusive despair; ripping apart families, societies and our ecosystems. collaboration between various disciplines and sectors, and the engagement of all relevant stakeholders from the initiation phase of I was born optimistic with an engineering architect father and a the project all the way towards final implementation. The Sand Motor community leader school teacher mother: believing that every now inspires the world that nature with its capacity to destruct is challenge is an opportunity as long as we include everyone - and actually our best friend in building sustainable and resilient coasts, combine all our will, energy and talent. The IPCC is also hopeful that it safeguarding our coastal towns and economies while improving the can be done. If only we dare to do it, and do it boldly. We have no time environment, the ecology, and mitigating climate change. to waste! In 2015, we set down a climate agreement and endorsed the United Nations Sustainable Development Goals. But paper alone will I think it is time to learn, replicate and scale up these nature-based not change the world. Across the globe, we still repair the damage solutions globally. We must start to educate the new generation caused by disasters, responding to the past instead of preparing us of engineers, designers, ecologists, policy makers, politicians and for the future and building. The Netherlands has been engaged in managers on the principles of nature-based solutions. We must the latter for more than thousand years. Ever since the institution develop credible narratives and the business cases and examples of our first regional water authority, water has become embedded of successful projects. Implement larger scale projects worldwide, in our culture and landscape, in legislation, governance, businesess evaluate them and disseminate the experience and knowledge and academia. Along with the Netherlands, a majority of the world’s gained. Involve communities in the planning and implementation and population is living in cities along rivers and coasts and growing. equip them with knowledge and financial means in order to scale up Prosperous places, but increasingly vulnerable due to climate change. and sustain such solutions, working side by side with governments and private sector. Scale up existing pilots and replicate these in Adapting to climate change is the way to bend the curve. The choice international consortia across the globe, in partnership with the between prevention and prepairing is false. Both are essential. We financial sector - multilateral development banks, the Green Climate need to start at the source: to reduce greenhouse emissions, and Fund, governments, private sector and pension funds. make sustainable use of our planet and all its resources. And at the same time we need to prepare boldly, comprehensively and inclusive We have no time to waste; the disasters of this world will not stop. for tomorrow’s extremes. The Netherlands’ coast is worth protecting, They have become the "new normal", more extreme year by year. The an amazing deltaic coastline. Protecting the country means working need for fast results is also an opportunity: ideal for setting up good on our coast and looking ahead systemically while merging natural business cases combined with political and societal action. Ambitious and human strengths. Nature has always been better in adapting enough to be attractive, and short and fast enough for targeted to change. However, with the speed and intensity of mankind's actions, with results and with hope. We can and we must act now. interventions and the massive pressure we put on our planet we have 2 to help nature progress, help nature help us. 3 Marcel Stive FROM COASTAL GENESIS TO NATURECOAST

Marcel Stive was program leader of the NatureCoast research Weak coastal links (Zwakke Schakels; 2004-present) program. He is professor emeritus of Coastal Engineering and To bring this multifunctional principle into practice, Minister Schultz former chairman of the department Hydraulic Engineering at Delft van Haegen presented the "Process plan weak links of the Dutch University of Technology. coast" in 2004. One of the eight weak links was the coast near Kijkduin and Hoek van Holland. Deputy Dwarshuis of the province of South Holland established a carefully composed Advisory Allow me to share my observations of the fascinating development Committee that included all relevant stakeholders. Their advice: no in our thinking about and coping with coastal challenges in the elongated, uniform dunes and widening of the beach, no permanent Netherlands. Specifically, this will cover the time following the buildings, but a concentrated mega-nourishment where natural completion of the Delta Works in the Oosterschelde in the 1970s processes would facilitate a dynamic dune and beach landscape. until the present, in the context of the emerging role of At that moment the concept of the Sand Motor was born. multidisciplinary research. Delta Committee 2.0 (Committee Veerman; 2007-2008) Coastal Genesis (Kustgenese; 1985-1987) Quite unexpected, the Delta Committee 2.0 was established at In the mid-1970s a transition took place when Rijkswaterstaat the request of Minister Huizinga. A remarkable decision, given shifted from funding fundamental research to funding more applied that no flood disaster had occurred recently, but most probably research. In the middle of the 1980s, it became clear that that a Hurricane Katrina in 2005 played a role. The composition of the further shift, towards more multi- and interdisciplinary research was committee was unusually multidisciplinary and strongly confirmed imminent, resulting in the Coastal Genesis project. But what was in the prevailing policies of room for the rivers and water, and a natural, fact the result of the Coastal Genesis project? I would argue that resilient coast. the first Coastal Bill (1990), the Dutch Centre for Coastal Research (NCK), which was established in 1994, and the current coastal policy Sand Motor realized (2011) (1990-present) all are indebted to the Coastal Genesis project. Amazingly, the Sand Motor was realized only five years after its inception. The challenge at that moment was to generate enough First Coastal Bill (Eerste Kustnota; 1988-1990) budget to monitor at least the morphological development in a time The results of Coastal Genesis were an almost seamless, logical when formally nothing had been put in place to do so, let alone the input to the rather remarkable first Coastal Bill. In 1987 all Delta ARGUS video tower. Delft University of Technology was able to works in Zeeland were close to completed, and so the time had solve this in a flexible way, using various sources including the EU- come to reflect on the future. Then Minister Smit-Kroes decided funded project NEarshoreMOnitoring (NEMO), while Rijkswaterstaat that the time was ripe to introduce a structural policy on coastal joined later. erosion. The coastline of 1990 was chosen to be maintained as the benchmark coastline. The type of interventions that were intended NatureCoast (2013-2018) to achieve this goal were as innovative as the policy, especially "soft" The pilot project Sand Motor was born as a multifunctional interventions as sand nourishments. answer to realizing a large number of functions, such as safety, nature values, recreation and innovation. Both from an academic, Water management in the 21st century technological and socio-political point of view, it was clear that the In August 2000 the Commissie Waterbeheer 21e eeuw (Water Sand Motor offered a unique “living lab” to conduct interdisciplinary Management Committee 21st century) published advise on the research. This triggered a broad consortium of Dutch institutions future of water policy in the Netherlands. Its main message was and industries to prepare an interdisciplinary NWO-STW (now TTW) that water needed more room and its management needed an research proposal. This proposal became the NatureCoast program, organizational principle. The Unie van Waterschappen (Union of in which disciplines have interacted in an unprecedented way. Dutch Water Authorities) endorsed the main principles, including the principle of combining water management with other interests, such 4 as nature conservation, spatial quality and recreation. 5 Cor de Boer SCIENTISTS AND END-USERS WORKING TOGETHER TO CONTRIBUTE TO SOCIETY

Just like the sea has tides, raging waves The knowledge acquired in NatureCoast and lapping water, the NatureCoast program is of a superb level, as evidenced by also has its storms and periods of calm. In the follow-up in various other NWO the ten years of Perspectief programs, I have program including the “Open Technology come across almost no other consortium Programme” (OTP) and the “Talent Scheme.” that consists of such a wide range of I look forward with considerable interest to parties, and that has developed into such a the fantastic results that this will yield. It is tight-knit group over the years. It did cost high tide for the researchers and end-users the group a considerable effort to keep of NatureCoast, and I hope that the intensive everybody on board. Yet that is also the relationships that have developed, will also challenge for multidisciplinary projects like lead to fantastic collaborations in the future. these: everybody looks at the subject in his Maintain those close links! or her own way and takes other interests into account. A success like this requires considerable commitment to and focus on the joint end result.

One of the successes in this regard was the involvement of end-users right Cor de Boer is head of the Department Life, from the start of the program. During Environment and Health, NWO Domain Rijkswaterstaat’s Sand Motor Congress Applied and Engineering Sciences. in 2016, and NatureCoast’s own final symposium in 2017, it also became clear just how successful NatureCoast was in seeking that connection with the end-user.

You can be rightly proud of what you have achieved: a consortium that has yielded a new innovation with societal impact. This innovation is now gaining a firm international footing too, which is securing economic impact for the Netherlands. It is a fantastic showcase that still manages to interest the media and the wider public. This ensures that a wider public also experiences the importance of applied and engineering Photo (left page): sciences. Cliff formation at the most seaward So, in my opinion, the program also does part of the Sand precisely what the Perspectief program Motor revealing intends: creating an intensive collaboration layers of shells between scientists and industry to solve (Photo by Sierd de innovation bottlenecks and contribute to 6 Vries) societal issues. 7 CONTENTS

PREFACE 2 MITIGATE TO ADAPT AND BUILD WITH NATURE, 1.5 DEGREES IS MORE THAN ENOUGH! Henk Ovink 4 FROM COASTAL GENESIS TO NATURECOAST Marcel Stive 6 SCIENTISTS AND END-USERS WORKING TOGETHER TO CONTRIBUTE TO SOCIETY Cor de Boer

ONE 12 INTRODUCTION 14 TOWARDS MULTIFUNCTIONAL COASTAL MANAGEMENT Alexander van Oudenhoven, Ewert Aukes and Arjen Luijendijk 18 MONITORING AND RESEARCH ON THE SAND MOTOR 20 READING GUIDE INTERVIEW 22 LENIE DWARSHUIS – PROVINCE OF SOUTH HOLLAND INTERVIEW 24 CAROLA VAN GELDER – RIJKSWATERSTAAT

TWO 26 GOVERNANCE ASPECTS INTRODUCTION 28 SANDY STRATEGIES IN SOCIAL CONTEXT Ewert Aukes 30 THE SOCIAL AND INSTITUTIONAL CONTEXT OF THE SAND MOTOR Ewert Aukes 34 NARRATIVES OF THE SAND MOTOR AND INSIGHTS INTO THE POSITIVE SPIRIT AROUND THE PILOT PROJECT Lotte Bontje 38 UNDERSTANDING PROJECT SUCCESS THROUGH FRAMING CONTENT AND CAPABILITY Ewert Aukes REFLECTION 42 MULTIFUNCTIONALITY AS A SUPPORTING FRAME AND STORYLINE Hans Bressers INTERVIEW 44 HANS KLEIJ – PROVINCE OF SOUTH HOLLAND INTERVIEW 46 RONALD WATERMAN – PROVINCE OF SOUTH HOLLAND

THREE 48 PHYSICAL SYSTEM INTRODUCTION 50 IMPACT ON PHYSICAL CHARACTERISTICS Arjen Luijendijk 52 OBSERVED BEHAVIOR IN A NUTSHELL Arjen Luijendijk 54 THE IMPACT OF LARGE-SCALE NOURISHMENTS ON NEARSHORE HYDRODYNAMICS Max Radermacher 58 THE IMPACT OF THE SAND MOTOR ON SANDBAR BEHAVIOR Jantien Rutten 62 DYNAMICS OF THE SAND PARTICLES Bas Huisman 66 THE IMPACT OF LARGE-SCALE NOURISHMENTS ON FRESH GROUNDWATER RESOURCES Sebastian Huizer

8 9 70 ENVIRONMENTAL IMPACTS OF AN INNOVATIVE BEACH NOURISHMENT REFLECTION 148 ECOSYSTEM SERVICES: AN UMBRELLA CONCEPT TO ESTABLISH INTERDISCIPLINARY LINKS Iris Pit Peter van Bodegom SPECIAL 74 MEGA PERTURBATION EXPERIMENT 2014 (MEGAPEX2014) SPECIAL 150 DATA MANAGEMENT SYSTEM Timothy Price Kees den Heijer REFLECTION 76 COASTAL RESEARCH AND MANAGEMENT: WHAT IS NEXT? SPECIAL 152 SAND MOTOR: A CULTURAL PHENOMENON Gerben Ruessink Satellietgroep INTERVIEW 78 JAN MULDER – RIJKSWATERSTAAT INTERVIEW 154 PATRICK BACON – DUNEA INTERVIEW 80 MICHEL PUGLIA – LIFEGUARD & RESCUE TEAM, THE HAGUE SEVEN 156 OPPORTUNITIES FOR SANDY STRATEGIES FOUR 82 DUNE DEVELOPMENT INTRODUCTION 158 EXPLORING THE POTENTIAL INTRODUCTION 84 THE JOURNEY OF A SAND GRAIN FROM BEACH TO DUNES Arjen Luijendijk Arjen Luijendijk 160 SANDY STRATEGIES 86 OBSERVED DUNE DEVELOPMENT Arjen Luijendijk and Jaap van Thiel de Vries Arjen Luijendijk 164 EXPLORING OTHER SANDY SHORES 88 OBSERVATIONS OF AEOLIAN TRANSPORT Arjen Luijendijk and Alexander van Oudenhoven Isaac Williams BACTON, UK 166 SANDSCAPING INSPIRED BY THE SAND MOTOR 92 EMBRYO DUNE DEVELOPMENT Arjen Luijendijk and Vera Vikolainen Marinka van Puijenbroek YSTAND, SWEDEN 168 GETTING LOCAL BEACH EROSION ONTO THE NATIONAL AGENDA 96 CONTRIBUTION OF VEGETATION TO DUNE DEVELOPMENT Alexander van Oudenhoven and Lotte Bontje Corjan Nolet NEGRIL, JAMAICA 170 PARADISE DIVIDED OVER A SEAWALL 100 WHY MORE SAND NOT ALWAYS RESULTS IN LARGER DUNES Alexander van Oudenhoven and Arjen Luijendijk Bas Hoonhout LIMA, PERU 172 FINDING COMMON GROUND FOR “MOTOR DE ARENA” REFLECTION 104 IMPROVING THE ABOVE-WATER DESIGN OF LARGE SAND NOURISHMENTS Arjen Luijendijk Kathelijne Wijnberg 174 A GLOBAL VIEW ON BEACH EROSION INTERVIEW 106 KEES VERTEGAAL – ADVISEURS ECOLOGIE Arjen Luijendijk INTERVIEW 108 BERT VAN DER VALK – DELTARES 176 OPPORTUNITIES FOR FRESH GROUNDWATER RESOURCES IN A MEGA-NOURISHMENT Marc Bierkens and Gu Oude Essink FIVE 110 ANIMAL LIFE INTERVIEW 178 JAAP VAN THIEL DE VRIES – BOSKALIS INTERVIEW 180 JAAP FLIKWEERT – ROYAL HASKONING DHV INTRODUCTION 112 THE HIDDEN ANIMAL LIFE AT THE SAND MOTOR Alexander van Oudenhoven EIGHT 182 REFLECTIONS 114 BURYING THE BOTTOM OF THE FOOD CHAIN Simeon Moons 184 THE MERITS OF INTERDISCIPLINARY RESEARCH 118 FLATFISH GROWING UP IN A SANDPIT Alexander van Oudenhoven and Arjen Luijendijk Marjolein Post 186 THE SHOW CASE EFFECT 122 WASHED ASHORE Henk Nieboer, Ecoshape Emily van Egmond 188 LEARNING FROM NATURE-BASED SOLUTIONS REFLECTION 126 THE BALANCE SHEET OF NATURE UNDER WATER Jaap Kwadijk, Deltares Peter Herman 190 MULTIDISCIPLINARY RESEARCH TO INFORM SOCIETY AT LARGE REFLECTION 128 SIZE MATTERS Roeland Allewijn, Rijkswaterstaat Rien Aerts 192 THE INTERDISCIPLINARY CHALLENGE INTERVIEW 130 MARTIN BAPTIST – WAGENINGEN MARINE RESEARCH Jill Slinger, Delft University of Technology INTERVIEW 132 LEO LINNARTZ – ARK NATURE DEVELOPMENT FOUNDATION 194 NATURECOAST AS ONE OF THE FIRST “LIVING LABS” Mark van Koningsveld, Van Oord & Topsector Water SIX 134 INTEGRATION OF RESEARCH EPILOGUE 196 MESSAGES FOR THE INTERNATIONAL COMMUNITY Todd Bridges INTRODUCTION 136 INTEGRATING RESEARCH THROUGH THE ECOSYSTEM SERVICES LENS EPILOGUE 198 THE SAND MOTOR: STEPPING STONE FOR A COASTAL CLIMATE LAB? Alexander van Oudenhoven Stefan Aarninkhof 138 THE ECOSYSTEM SERVICES OF THE SAND MOTOR Alexander van Oudenhoven and Arjen Luijendijk 200 BIBLIOGRAPHY 142 ENGINEERING THE ECOSYTEM SERVICES OF THE SAND MOTOR 203 REFERENCES Arjen Luijendijk and Alexander van Oudenhoven 204 COLOPHON 146 SHAPING FUTURE SANDY SOLUTIONS Arjen Luijendijk and Alexander van Oudenhoven 10 11 ONE | INTRODUCTION – INTRODUCTION ONE

12 13 Alexander van Oudenhoven, Ewert Aukes and Arjen Luijendijk TOWARDS MULTIFUNCTIONAL COASTAL MANAGEMENT

Alexander van Oudenhoven was active in Climate change is the most formidable context. This means that we need to fully the NatureCoast program as a postdoctoral challenge that our ever-increasing world understand how coastal ecosystems researcher at Leiden University between population faces, and it poses special function, as well as their societal context. 2015 and 2018.He focused on integrating the problems for those living near coasts. This knowledge is crucial if we are to create program’s scientific findings, thereby looking People have always been attracted to the integrated multifunctional coastal protection at the interactions between nature and coast, as a place to live and work, and to solutions that have minimal environmental people, the potential benefits that nature- relax. By 2050, around half of the world’s impact and are widely appreciated. inclusive coastal management can generate. population is expected to live near the coast, He is currently working as an assistant the vast majority in developing countries. The shift away from treating symptoms professor at the Institute of Environmental How will we cope with rapidly rising sea towards integrated, multifunctional designs Sciences at Leiden University, working on the levels and more intense and frequent storm requires a new approach. Throughout interface between biodiversity, ecosystem surges? the Netherlands, the Building with Nature services and societies’ quality of life. approach has been adopted. The key to Although retreating from coastal areas this innovative approach is using prototype Ewert Aukes was active in the NatureCoast might not be such a bad idea, this is an pilots to develop new knowledge and program as a postdoctoral researcher, unlikely option for most coastal settlements. insights. In this book, we present the shortly after obtaining his PhD within the This means that active protection of urban findings of a multidisciplinary research same program in 2017 at the University areas and infrastructure against flooding program, called “NatureCoast”, which of Twente. He currently works at the will remain our primary focus. Artificial studied a full-scale coastal protection pilot department of Science, Technology and protective barriers, such as concrete dikes, project, the “Sand Motor”. Policy Studies at University of Twente, as a dams and breakwaters have traditionally postdoctoral researcher. been the go-to way to deal with coastal Building with Nature protection. However, such hard structures Building with Nature (BwN) is a Arjen Luijendijk was active in the have always had the single aim of providing proactive approach to surface water NatureCoast program as a postdoctoral coastal protection, without considering their management. The approach advocates researcher at Delft University of Technology impact on the coastal ecosystem. In other an integrated approach that harmonizes from the start in 2013 until the end in 2018. words, traditional coastal management coastal management solutions with the He focused on setting up the interaction solutions were treating symptoms; building requirements of ecosystems. Decisions between the PhD researchers and end-users, coastal protection structures in nature often must be taken about desired societal and as well as integrating the research findings. created new problems or moved existing ecological functions, which means that the He worked on developing integrated model problems to other places. state and the functioning of the ecosystem forecasts and developed the world's first has to be studied and understood before a global beach erosion map. He is currently Throughout history, the fate of the design can be proposed. working as a specialist at Deltares and Netherlands has always been intimately as a researcher at the Delft University linked to the sea. Without our coastline The BwN approach maintains that this of Technology on predicting the future protection and inland water management, knowledge is crucial if environmental behavior of the world's beaches. two-thirds of the country would be and nature concerns are to be integrated under water. However, we have also into coastal infrastructure projects. By realized that just treating symptoms is considering how the local ecosystem

Photo (left page): no longer sufficient. Protecting people can become part of the solution, project – INTRODUCTION The Sand Motor being constructed, as and infrastructure will always remain the managers anticipate legal opposition and

seen from the dunes of Ter Heijde. The main aim of coastal management, but the avoid having to create alternative nature ONE sand is being sprayed on through so-called impact on the environment must also be areas. This is almost directly opposite to 14 rainbowing. (Photo by Arjen Luijendijk) considered, as well as the wider societal mainstream infrastructure approaches, 15 Photo (left page): which tend to focus on the current situation focused on six themes: coastal safety, NatureCoast researchers sharing their rather than the future and build in nature, dune formation, marine ecology, terrestrial findings during an excursion of the rather than with nature. Besides being ecology, hydrology and geochemistry, Rijkswaterstaat Sand Motor conference in proactive, the BwN philosophy attempts to and governance. NatureCoast researchers 2016. Throughout the years, our researchers maximize the use of natural processes in collaborated actively with researchers from have provided numerous excursions to the infrastructure projects. The Sand Motor is the NEMO project (Page 19), who studied the Sand Motor. Excursions, discussions and one of the first large-scale applications of behavior of the Delfland coast, including the guest lectures are just some of the ways the BwN approach. Sand Motor. through which NatureCoast has been in dialogue with end-users and society. (Photo The Sand Motor The purpose of this book by Alexander van Oudenhoven) The Sand Motor is a large sandy peninsula, Interdisciplinary research is crucial to constructed in 2011 on the Dutch North Sea support integrated coastal protection coast near The Hague. This unprecedented solutions and to put the lessons learned pilot project involved placing 21.5 million m3 into practice. In this book, we will to tell you of sand on and in front of the beach with more about both the innovative mega- the aim that it would spread along the nourishment, the Sand Motor, and about coast. Sand nourishment itself is not a new the uniquely interdisciplinary NatureCoast method to prevent coastline erosion. In program. We share concrete research fact, the Netherlands has had a structural findings about the Sand Motor’s behavior nourishment program since the early and about the societal context of the pilot 1990s. However, the Sand Motor is a Sand Motor. We also reflect on the merits unique beach nourishment due to its size, of collaboration and integration within a the design philosophy behind it, and its multidisciplinary research program. multifunctionality. The volume of sand used for the Sand Motor is about five times that of an average nourishment. The Sand Motor is intended to feed the adjacent coasts by using the natural forces of tides, waves and wind; in a way, it is built to “disappear”. Another unique aspect of the Sand Motor is that it combines the primary function of coastal protection with the creation of a new natural landscape that also provides new leisure opportunities. From the outset, “learning by doing” has been a crucial part of the project. Because of its innovations, the Sand Motor has triggered considerable political and scientific interest from all over the world. Large research consortia such as the NatureCoast program were formed to conduct interdisciplinary research on the Sand Motor.

Interdisciplinary research: NatureCoast NatureCoast is the largest research program that focused on the Sand Motor. The program was carried out by a large consortium of knowledge institutes, and the research was conducted in cooperation with

end-users from private companies, research – INTRODUCTION institutes and governmental organizations.

The Dutch Technology Foundation (NWO- ONE TTW) supplied the largest share of the 16 project funds. The research in NatureCoast 17 Table 1. Project structure of the NatureCoast program. MONITORING AND RESEARCH ON THE SAND MOTOR

Project Purpose Personnel Organizations Monitoring and Evaluation Program (MEP) environment and its evolution over time, NatureCoast was unique among nationally The Dutch Ministry for Infrastructure and which is why many of NEMO’s findings will funded research programs. Two factors Utilization Further articulate research questions in 1 professor Delft University of Technology Environment commissioned an extensive also be discussed in this book. stand out. Encouraged by the funding close collaboration with end-users monitoring and evaluation project (the so- organization, the program organized regular called MEP study). The MEP study evaluated The NatureCoast program end-user meetings, in which NatureCoast Integration Search for synergies between science 3 postdocs Delft University of Technology, Leiden the performance of the Sand Motor in terms The diversity of the topics and the researchers shared their findings with projects; produce interdisciplinary research University, University of Twente of the original three project aims: stimulating complexity of their interrelations called end-users and worked on scientific issues questions dune growth in the project area, developing for a coherent and interdisciplinary program. that cut across the disciplines. This ensured additional recreation and nature areas, and This interdisciplinary requirement was the strong involvement of end-users Data Facilitate data storage, sharing and 1 staff member Delft University of Technology knowledge development through "learning already recognized during the funding and took advantage of their practical dissemination by doing." In addition, the MEP study application process. The definitive program knowledge, insights and experiences. In evaluated the feasibility of using the Sand structure reflected this ambition. In addition addition, three postdocs had the dedicated Science 12 PhDs, Delft University of Technology, Utrecht Motor at other locations in the Netherlands. to NWO-TTW, NatureCoast was financially task of integrating the research findings and S1 Coastal Safety Interaction and adjustment of the seafloor 7 non-scientific University, University of Twente; supported by Boskalis, Deltares, encouraging collaboration among the PhD and effect on coastal defense personnel, Wageningen University, VU University, Royal The MEP was always intended as a the Province of South Holland, candidates across scientific disciplines. Sea currents and effect on swimmer safety 6 principal Netherlands Institute for Sea Research monitoring project, focusing on gathering Rijkswaterstaat, Van Oord and Wageningen S2 Dune Formation Effect of organisms on dune formation investigators data and answering that the Sand Marine Research. Sediment exchange between beach and Motor works. Hence, it does not answer dunes fundamental scientific questions regarding NatureCoast was structured around four S3 Marine Ecology Marine food webs in the shallow coastal sea the Sand Motor, such as on how and why the projects (Table 1). It included twelve PhD Effect of organisms on the shallow coastal Sand Motor works. This task was left to the candidates as well as three postdoctoral sea research programs, of which NatureCoast researchers from six different Dutch S4 Terrestrial Vegetation succession in existing dunes was the most extensive. This book intends to universities and one research institute. While Ecology Impact on community assembly in beach shed more light on the underlying processes the PhD candidates were tasked with the ecosystems behind the Sand Motor. fundamental knowledge questions in their S5 Hydrology and Interaction between hydrology and research fields, the postdoctoral researchers Geochemistry geomorphology NEMO guided the integration of the research Chemical composition of nourished sand NEMO is short for "Nearshore Monitoring results. S6 Governance Freeridership & ecosystem services and Modeling." NEMO is an ERC-Advanced Societal acceptance of large nourishments Researchers Grant project involving three Note that all 12 PhD researchers and all other PhDs and three postdocs, led by the Delft authors will be introduced briefly in the University of Technology. chapters to which they contributed. Besides the three postdocs (as introduced on NEMO aims to advance our ability to Page 15) two other postdocs also forecast the shape of our coast in the contributed to the program. Timothy coming decades. The heart of this project Price (predecessor of Alexander van was an intensive measurement campaign Oudenhoven) was involved in NatureCoast along the Delfland coast. Researchers from May 2013 to October 2014, after which simultaneously measured surf zone he joined Utrecht University as an assistant

topography, beach position, dune profiles, professor. Vera Vikolainen (predecessor of – INTRODUCTION current speeds, local wave heights, and Ewert Aukes) was a postdoc from January

even sediment transports at the highest 2013 to March 2017, after which she joined ONE resolution possible. This data provides a the European Parliament in Brussels as a 18 more complete understanding of the coastal policy analyst. 19 Figure 1. Introducing the PhD's s in the NatureCoast Bottom row from left to right: scientific research program. Jantien Rutten, Max Radermacher, Simeon Moons, Marinka van Puijenbroek, Sebastian READING GUIDE Top row from left to right: Iris Pit, Isaac Huizer, Marjolein Post. Williams, Corjan Nolet, Emily van Loon van Egmond, Lotte Bontje, Ewert Aukes.

Each chapter of this book can be seen as a dialogue between researchers involved in the NatureCoast program and the end- users of the information. In addition to presenting the key research findings of the involved PhD researchers, each chapter also features a personal reflection by the principal investigator(s), partly looking back at the combined research findings and partly looking forward towards future developments in the field and their application. Finally, each chapter also features reflections from end-users; practitioners, policy makers and other stakeholders who are interested in how to put the findings to good use. We note that NatureCoast has always embraced discussion and dialogue. The views expressed by the investigators and end-users in this book are their own and do not necessarily reflect the vision of NatureCoast.

The outline of the book is shaped as an hourglass – after this broad introduction, we zoom in on specific research findings, and zoom out again to integrate those findings and to reflect on broader applications. Chapters 2 to 5 highlight specific research findings of the NatureCoast PhD projects and, if applicable, of related projects. The chapters deal with the societal context in which the pilot Sand Motor came to be, the workings of the physical system of the Sand Motor, dune development at the Sand Motor, and the impact of the mega-nourishment on its animal life.

After this, in Chapters 6 to 8, we relate the research findings to broader, overarching issues, such as multifunctional management of our coastlines and the worldwide application of sandy strategies. We summarize the main overall findings and put them in the context of the original aims of the Sand Motor, to assess how the characteristics of the Sand Motor have contributed to expected outcomes and also created more surprising ones, and to consider how this will continue in the future. With that knowledge, we reflect on the potential application of new sandy strategies, both in the Netherlands and abroad (based on experiences with four international case studies that we have been involved in). In the final chapter we reflect on the NatureCoast program, before leaving with reflections from key experts and end-users on the program and the usability of its findings. – INTRODUCTION ONE

20 21 JULY 2011 Former member of the Gedeputeerde Staten (Executive Council) LENIE DWARSHUIS – PROVINCE OF SOUTH HOLLAND

INTERVIEW

In what way is the Sand Motor unique to how will the flora and fauna react? Because they were all initially skeptical. Nevertheless, you as end-user? the Sand Motor is an experiment, but a through mutual efforts, they ultimately “The Sand Motor is unique because it serves "calculated experiment", we aren’t just stepped on board. Now they are also multiple purposes. That was new at the trying something. And with a calculated unrestrained in their enthusiasm, and have time, because before we had mainly done experiment, the more disciplines you participated in new projects such as the underwater sand nourishments. With that can accommodate, the better you can Hondsbossche Duinen with a very different you do increase coastal safety, but you connect to what you expect and what perspective, based on the knowledge, do not contribute to other functions or can be monitored. And, hence, the clearer expertise, experience and public support for demands from society. With the Sand Motor, it becomes what you can do with it the Sand Motor. And that is great to see.” there is also room for nature and recreation, afterwards.” and it serves an innovative way to increase How does the Sand Motor and the safety by building with nature.” What are the main findings of the knowledge and experience gained there NatureCoast program for you as end-user? fit within your vision of the future of the How do you see the role of scientific “For me, these are very broad and certainly Delfland coast? research at the Sand Motor, as end-user? not only technical. The point is that there is "I am still very active in coastal “Indispensable. Because, even with all the every reason to say, based on the current development, for instance as chairman coastal knowledge and expertise present research, that we now have experience of the Stichting Nieuw Holland, which in the Netherlands, the Sand Motor was and knowledge on how this concept can also helped me at the time to get private still an experiment. The question was: Will be further applied. Not only in South partners involved with the Sand Motor. Our nature, which of course always finds its own Holland, but also internationally. As far as I foundation is now working on a position way, do what the clever scientific minds am concerned, the Sand Motor has always paper concerning the follow-up of the had calculated with all sorts of computer been a commodity - Dutch knowledge and Sand Motor - What can the coast mean models? That was interesting for two expertise on sustainability that is gained for the Netherlands, and South Holland in reasons. First, for technical reasons: are we here can be marketed elsewhere. For me, particular? The four cornerstones are flood ready to predict what will happen with this the drive was to be able to take the next safety, large-scale nature development, kind of interventions in nature, and with steps with much more knowledge and metropolitan location policy, and innovation building with nature? The second reason certainty.” and sustainability. All from the central is more future-oriented: if things do go as question: How can a good coastal policy expected, and all this prior knowledge and “Another outcome of the program that has be climate-oriented but also innovation- expertise turns out to work in practice, what struck me greatly is that the resistance to oriented? And this means building on the are we going to do next? Because for me, the Sand Motor disappeared like snow in ideas behind the Sand Motor and the lessons the Sand Motor has always been a pilot or the summer. Coastal residents and other learnt from it.” an overture for the question what would stakeholders are now extremely enthusiastic come next. And that is what I am currently about the project. At first we saw many working on, so as an end-user, the research crowded rooms with a lot of upset people, on the Sand Motor is also a stepping stone and a lot of distrust. But apparently seeing to new horizons for me.” is believing. People who were initially afraid that their business activities such as beach How relevant is multidisciplinary research pavilions, boat rentals, and kite surfing

on the Sand Motor for you as end-user? would no longer have a future because – INTRODUCTION “One should of course try to bring together of the Sand Motor, have seen that the

all knowledge, expertise and science in opposite is true. The same goes for the ONE the Netherlands. In the field of water nature organizations, World Wildlife Fund, 22 management, but also concerning ecology: Natuurmonumenten, Stichting Duinbehoud: 23 DECEMBER 2011 Project manager for the Monitoring and Evaluation of the Sand Motor CAROLA VAN GELDER – RIJKSWATERSTAAT

INTERVIEW

In what way is the Sand Motor unique for How relevant is multidisciplinary research creating such a large-scale nourishment, you as end-user? on the Sand Motor for you as end-user? how measuring devices can be optimally “The Sand Motor is unique for Rijkswaterstaat “The Sand Motor would not have been built used, and what lessons we can learn. But because it was a pilot project, and we had if the project had not been multifunctional. the findings go beyond just the Sand Motor, never carried out such a large-scale First, it would have been far too expensive as we have more large sand nourishment intervention before. One of the reasons for flood protection alone. But when projects, and will have many more in the we started this pilot was to see how the you combine multiple functions many future. Currently, we are conducting a major entire coastal system would respond to a stakeholders are interested, and the strength project at the Ameland tidal inlet, and are mega nourishment. Our main objective is, of this project is that it actually involved all applying the results from our own research of course, coastal flood safety. To keep the those stakeholders. This generated more and that of NatureCoast.” coastline in place, and to let the coastal appreciation of a multifunctional solution and foundation keep up with sea-level rise, support for it. In order to coordinate, monitor What findings from the NatureCoast study we have a national program, Kustlijnzorg and analyze all these functions, and to go beyond findings of the Monitoring and (Coastline Management). The Sand Motor identify their added value, multidisciplinary Evaluation Program (MEP)? project is thus unique because the method research is necessary. For Rijkswaterstaat it “This is a Monitoring and Evaluation differs from our usual way of working, and was interesting to see how this added value Program that Rijkswaterstaat has set up for furthermore because with this pilot we related to flood safety, nature and recreation the Sand Motor. We use a large number of intend to look into future proof ways of could be used on other parts of the coast, measuring devices, which were also used by coastline management considering which also face sea-level rise challenges. NatureCoast researchers. Iris Pit for example, sea-level rise.” Protecting the Delfland coast is just one of conducted research into the chemical our tasks, and the multidisciplinary lessons composition of the water and sediment, and How do you see the role of scientific we learned here are a real added value that found naturally occurring heavy metals in the research at the Sand Motor, as end-user? the Sand Motor has brought to the rest of area of the Sand Motor. We then examined “What I see is that the Sand Motor has given the coast.” together whether this was specific to the scientific research a huge boost, because Sand Motor or if it also occurs elsewhere.” it requires new lines of thought and new What are the main findings of the activities on the part of all parties. This allows NatureCoast program for you as end-user? “Another aspect is swimmer safety. This is research to be conducted on a range of new “ We are interested in many aspects of a concern for both Rijkswaterstaat and the issues; beyond the many aspects of flood NatureCoast's research, and intend to Province of South Holland, which is formally safety, the project requires research apply them. These include the governance responsible for swimmer safety. Of course, on nature and recreation. We are pleased research that Lotte Bontje and Ewert Aukes we didn't know in advance how the area about this, because this type of research worked on. Their study showed that, in would react to a Sand Motor, and that is why also offers us broader insights for the future order to properly set up this kind of policy Rijkswaterstaat developed a swimmer safety of coastal management and maintenance.” measure, you must not forget to do so in a application to indicate dangerous situations narrative way: why are you doing this? What at the Sand Motor. Max Radermacher’s “Of course, at Rijkswaterstaat we mainly are the benefits for the various parties? This research contributed to the wider application focus on monitoring and more applied is not standard procedure for organizations of this app, as well as investigating how such research; and with the help of fundamental like Rijkswaterstaat and the Ministry, and in a broad approach affects swimmer safety. research by scientists, we are trying to take my opinion this insight is crucial and needs Working together in this research program

that a step further. We are interested in to be included in the policy-making process. ensures that we can now incorporate the – INTRODUCTION what additional knowledge we can gain And from a technical perspective, I am methods he used in other projects. This kind

from this pilot that can be used in our thinking of the studies by Max Radermacher of added value certainly makes it relevant ONE end-evaluation of the Sand Motor and in and Jantien Rutten. These deal with how for Rijkswaterstaat to participate in scientific 24 other projects ” swimmer safety can be considered when research programs as an end-user.” 25 TWO | GOVERNANCE ASPECTS – GOVERNANCE ASPECTS TWO

26 27 Ewert Aukes SANDY STRATEGIES IN SOCIAL CONTEXT

INTRODUCTION

All over the world, climate change and sea-level rise are forcing of people, became important. It began to play a central role in how societies to take action. They need to develop new and innovative supporters talked about the Sand Motor, even though their stories approaches to adapt. But such technological innovations do were all slightly different. The Sand Motor’s multifunctional character not develop in a social vacuum; they are often closely linked to became its most important advantage, and multifunctionality finding solutions to social challenges. The successful introduction became a key argument to convince others of its usefulness. of technological innovations, such as the Sand Motor, depends Finally, our story would be incomplete without a view of the future on whether a range of political and societal parties are willing (Page 42). It looks like multifunctionality as a frame or storyline and able to commit themselves to this solution. Considering is here to stay in societal and political discussions about sandy the unprecedented scale, and thus potential social impact, of a strategies and beyond. project like the Sand Motor, it should come as no surprise that its introduction was not without challenges. In this chapter, we discuss why many political and societal parties came to support the Sand Motor pilot project.

We look at the social context of the Sand Motor from three related viewpoints. First, we place the Sand Motor in its social and political context. To understand the societal acceptance of the Sand Motor, we have to begin with the social and political background (Page 30), the history of Dutch coastal management. A specific set of spatial planning challenges along the west coast of the Netherlands guided the choice of location for the Sand Motor. In addition, Dutch coastal management reflects the democratic traditions in the country. This means that policy actors at many different levels can influence decision making, with citizens also having ample opportunity to participate.

Next, we consider aspects that affected the acceptance of the Sand Motor by organizations involved in the decision-making process. The second viewpoint explores how positive storytelling (Page 34) can become contagious and has contributed to the success of the Sand Motor. People tell stories all the time. The simple structure of a story – problem-development-solution – is a typical way of organizing our thoughts. We often communicate through stories, and so did decision makers and organizations dealing with the Sand Motor. The story element of multifunctionality linked the stories of many actors involved in the development of the Sand Motor.

The third viewpoint looks at how multifunctionality became an important argument, a successful frame to convince parties that

did not yet support the idea of a Sand Motor (Page 38). These – GOVERNANCE ASPECTS insights help us understand the importance of multifunctionality in

coastal management as well as technological innovations in general. TWO This multifunctionality, the fact that the Sand Motor had different 28 perceived advantages that were appreciated by different groups 29 Figure 1. Ewert Aukes Timeline of Dutch flood risk management in the 20th century. (Photo credits: Eastern Scheldt, Closure Dam and Maeslant THE SOCIAL AND INSTITUTIONAL CONTEXT Barrier: beeldbank.rws.nl; Sand Motor: Rijkswaterstaat, Joop van Houdt; OF THE SAND MOTOR Hondsbossche Dunes: Boskalis)

Northwesterly storm The Flood Disaster Large-scale floods Large-scale floods Dutch coastal management history was still low in the first half of the nourishing beaches on an unprecedented in North Holland (Watersnoodramp) river Meuse river Meuse Historically, socio-economic activities in the 20th century. scale. Gradually, a transition began Netherlands have been mainly concentrated towards more nature-friendly solutions in the estuaries of the Rhine and Meuse In 1953, the southwest of the Netherlands in coastal management. Starting in 1990, rivers. The urban sprawl resulting from this was struck by another major flood event: a Rijkswaterstaat, the Public Works Agency activity is currently the home to a large Northwesterly storm combined with spring of the Ministry of Infrastructure and share of the Dutch economic productivity, tide. Embankments in different places Water Management began maintaining a not to mention its population. In an area succumbed to the ferocity of the storm. reference coastline, based on the Dutch so close to the North Sea and with such As a result, 1,800 inhabitants perished and coastline at that time. Annual, small-scale 1900 1920 1940 1960 1980 2000 2020 socio-economic importance, coastal economic damage was high. The disaster foreshore or beach nourishments became protection is a prime requirement. For came to be known as De Watersnoodramp the new standard approach to maintain Southern Sea Works centuries, the general principle of coastal (The Flood Disaster) and is a pivotal this Basiskustlijn (BKL; reference coastline, protection in the Netherlands was building event in modern Dutch history. In the brown color in Figure 1). embankments to protect areas in danger of wake of the storm, the Dutch government Delta Works flooding from the sea. convened a commission of high-ranking In the 2000s, multifunctional space was coastal management and civil engineering still in high demand. By now, Dutch coastal Relying on embankments for coastal experts to draft a strategic plan to prevent managers had acquired considerable Routine nourishment management continued in the 20th century a similar disaster from ever happening experience with beach nourishment. A program (Figure 1). The last large-scale coastal again. This so-called First Delta Committee combination of nourishment technology and management program in the Netherlands Plan came to be known as the Deltaplan. Building with Nature was proposed. This that relied primarily on embankments, It proposed closing off additional inland spatial planning philosophy marked a subtle were the Zuiderzeewerken (Southern Sea waters utilizing newly available steel-and- transition from aiming for one function to Works). As a result, embankments were concrete engineering technology. Again, attempting to include as many functions built and fortified, as protection against these structures were to be built against as possible, moving from monofunctional nature. Necessitated by major flooding in nature and serve the sole function of coastal to multifunctional land use. Building with 1916, this program intended to reduce the protection. Nature promotes an ecosystem perspective; coastline of the Netherlands by closing off not only minimizing ecological damage, but the Zuiderzee, which was subsequently Meanwhile, the Netherlands experienced also developing nature and using natural called the IJsselmeer (Lake IJssel). Reducing rapid urbanization and population growth. processes for societal aims. the coastline would simplify maintenance As a result, competition grew among Closure Dam Eastern Scheldt Sand Motor of coastal protection works and decrease land uses in the increasingly crowded A pilot project was proposed that would (Afsluitdijk) Storm Surge Barrier the protection needs in closed-off regions. coastal areas. Coastal management could experiment with many functions at once. Among other things, the Zuiderzeewerken no longer focus exclusively on coastal And thus, the idea for a Sand Motor, in included the construction of the Afsluitdijk protection. New ways of integrating land- some ways a scaled-up version of previous (Closure Dam), a 32.5 km long causeway use functions needed to be explored, nourishments, was born. The Sand Motor through the Wadden Sea connecting sparking interest in land reclamation was designed to utilize natural North Sea the Dutch provinces of Friesland and and integrated policies. From the 1980s currents. In that way, it would serve coastal North Holland. With a main aim of coastal onward, the effects of climate change, such protection on location and, by deliberate protection, the Southern Sea Works can as rising sea levels, further complicated erosion and re-sedimentation, at other

be viewed as a monofunctional project. the situation. These developments locations as well. In addition, the Sand Motor – GOVERNANCE ASPECTS Limiting the coastal protection program to coincided with growing knowledge of provided opportunities for developing

monofunctionality was possible, because ecosystems and their contributions to nature, recreation and leisure opportunities, TWO Maeslant Barrier Hondsbossche the flood events triggered a heightened human wellbeing. Innovations in dredging as well as promoting economic productivity. 30 Dunes sense of urgency, while population pressure technologies enabled sand dredging and The Sand Motor is arguably the first 31 Figure 2. large-scale Building with Nature design put place since the formulation of a reference long-term program in its final report in Annual sand nourishment volumes in the into practice. coastline in 1990, beyond which the 2008, entitled "Samen werken met water" Netherlands since 1991; the 21.5 million m3 of Dutch coastline is not supposed to erode. ("Working together with water"). The the Sand Motor is not included in the graph. It is no surprise that the Sand Motor Rijkswaterstaat performs annual inspections Second Delta committee advocates a (Figure by Rijkswaterstaat) was developed in the province of South of the coastline, leading to nourishment coastal management approach that ensures Holland. This province is home to a large activities, where necessary. Every four long-term flood protection and freshwater part of the urban conglomerate known years, Rijkswaterstaat compiles a long- management strategies. as the Randstad, and the province is range nourishment plan, with an annual faced with significant spatial problems budget of 12 million m³ sand for immediate Although this legal and political structure associated with population density. At the nourishment (Figure 2). Rijkswaterstaat also represents the legal blueprint for coastal 20 40 time, leisure areas for inhabitants of the oversees applications for integrated water management projects, this is certainly growing cities were becoming scarcer. The permits, which have to be requested when not the only way such projects can be European Natura2000 legislation required flood defense structures are constructed organized. While non-experimental projects construction projects to include nature or modified. Such projects also need an are generally initiated and managed by )

3 compensation, which was becoming more environmental impact assessment, which water authorities under the Water Act,

m and more difficult to achieve. The Sand evaluates the environmental impact of experimental projects can be carried out by 6 15 30 Motor offered an opportunity to innovate a preferred solution and compares it to actors who are not water authorities, as was with spatial policies, and the provincial alternative solutions. the case with the Sand Motor. government seized this opportunity with both hands. Under the Water Act, provincial governments are not considered as 10 20 The arena of Dutch coastal management water authorities. Nevertheless, they are The overall Dutch coastal management thoroughly involved in water management, ambitions were stated in the 2009 National supervising regional water authorities Water Plan. First, the coastal foundation and municipalities and coordinating their is to grow proportionally to sea-level rise. activities. Provincial governments have Second, this process is to be stimulated a significant influence on the coastal 5 10 BKL-exceedances (%) using sand and the natural dispersal of this management process thanks to their role of sand along the coast. Third, in addition to approving project plans. Nourishment volumes (10 coastal protection, coastal management should focus on a balanced development of Like provincial governments, municipalities nature, economy and recreation. do not officially count as water authorities, 0 0 although they do have certain water The 2009 Water Act remains the main management tasks unrelated to coastal water and coastal management policy in the management. Although they are not

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 Netherlands. It relates water management responsible for coastal safety and spatial to other policy areas, such as nature, planning, municipalities are responsible for Year environment and spatial planning. The Water zoning plans. In the zoning process, other Act distinguishes two water authorities. actors who might be affected by coastal Water authorities manage coasts within management – such as drinking water Shoreface nourishments their territory, while the State deals with companies, nature NGOs or knowledge coastal issues that overlap the boundaries institutes – can influence the decision- BKL-exceedances of the water authorities. Water authorities making process through the general public have the task of planning, building and participation mechanisms in place. For Shoreface nourishments forecast 2017 maintaining regional coastal management example, final project plans have to be projects, as long as the coastal stretch in available to the public at the competent question is not a primary defense structure. authority, where they can be inspected by Beach nourishments The national government defines strategic everyone. policy and manages supra-regional defense

Beach nourishments forecast 2017 structures. Besides these annual and multi-annual – GOVERNANCE ASPECTS coastal management activities, the national

10% norm exceedances Rijkswaterstaat is the national executive Delta program is in place to guarantee TWO agency entrusted with the coastal long-term safety from flooding. The 32 management program. This has been in Second Delta committee established this 33 Figure 1. Lotte Bontje Overview of the narrative research approach. NARRATIVES OF THE SAND MOTOR AND INSIGHTS

Personal narratives Shared INTO THE POSITIVE SPIRIT AROUND THE PILOT PROJECT (of personal) biographies Interviewees Researcher listens experiences Researcher analyses about the project tell about and transcribes (comparing, their experiences clustering) Lotte Bontje obtained her PhD at the Pilots such as the Sand Motor are only level, which then had to be implemented Faculty of Technology, Policy and possible with the cooperation of many (top row of Figure 3). This is how some Management, section Policy Analysis at organizations - represented by even more local officials and local actors experienced Delft University of Technology in 2017. individuals. Each of these individuals will the development of the Sand Motor. She currently works at the municipality of have experienced the process differently. The narrative covered several years and Lansingerland, as an advisor for household Generally, people make sense of placed the Sand Motor in the local context. waste and public space. experiences through our so-called "narrative Interestingly, the novelty of the project understanding", arranging our thoughts and the associated uncertainties for the Dissertation title: using stories. Through their context, region were not necessarily interpreted “Narrative perspectives on the development characters, events and development, stories as negative. The project offered several Figure 2. of coastal pilot projects.” provide recognizable structures that help positive prospects, including the chances Graphical us organize our experiences. Research into for large-scale natural processes along the representation of the PhD supervisors: the stories associated with a pilot project, coast, and opportunities for the region as a narratives. Jill Slinger (Delft University of Technology) such as the Sand Motor, is therefore research result of the uniqueness of the Sand Motor. Wil Thissen (Delft University of Technology) into the personal experiences of project participants. In the second narrative, the Sand Motor is viewed as an iconic outcome of a long In this section, we explore the personal evolving process. Starting in the seventies narratives of the people involved in the start or eighties, this story has a far longer of the pilot Sand Motor. First, we describe timespan. This narrative also has a higher the peoples’ shared narratives distilled from spatial scale than the first; it simultaneously the Sand Motor study. Second, we discuss refers to regional and global processes, An iconic departure Something unknown that the insights that these narratives provide. such as the development of Integrated A stage in needed to be implemented Coastal Zone Management or global an incremental process Three narratives of the Sand Motor developments in coastal engineering. in the region The starting point of our research were Interestingly, this narrative has at least the personal narratives of the participants two slightly different versions. Some involved in developing the Sand Motor interviewees from the field of coastal (Figure 1). Each personal narrative has engineering consider the Sand Motor a certain time span, spatial orientation, “a new step in the development of sequence of events and problem-solution nourishment techniques” serving multiple structure. We revealed three commonly purposes. Others view the Sand Motor as shared Sand Motor narratives (Figure 2). “a new step in the integrated development Each of these reflects how a group of of coastal zones,” because integrated people explained the realization of the pilot development incorporates the idea of Sand Motor. Note that these biographies multifunctionality. In such a way, several represent personal narratives and mutually reinforcing stories about the Sand interpretations, not the official view of the Motor became interwoven. The majority of agencies or institutions that the individuals the personal narratives fit into the category

work for. of “iconic departure biography.” – GOVERNANCE ASPECTS

The first narrative presents the Sand Motor The third narrative pictures the Sand TWO as an unknown and unfamiliar thing thrust Motor simply as a stage within an on- 34 upon the region from a higher administrative going and incremental process of 35 Figure 3. Three biographies: Details and Based on personal Time- Spatial coastal development. In this perspective, Sand Motor, more and more people began In short, the multifunctionality of the Overview of the The Sand Motor... varieties within the narratives from the: span orientation the Sand Motor has the advantages of to share elements of the positive stories. Sand Motor has allowed actors to select three narratives on biographies: limiting disturbance to biodiversity and Discovering these elements in different and couple diverse aspects into their the development the ecosystem while promoting efficient personal narratives indicates how effective own narratives of the project. This has of the Sand Motor. 1 As something a Providing Municipality, surfer Some Local to interaction and collaboration between storytelling was during the development of definitely helped to connect the initiators Note that these are (unknown) that opportunities for association, nature years regional level different actors, but the pilot is not the Sand Motor. of the project and the many other interpreted personal needed to be actors development, water necessarily an innovation. Although this organizations involved. The resonance of narratives, and do implemented in the authority narrative was initially based on only one Did multifunctionality help the pilot positive storytelling has contributed to the not represent the region b Potentially causing Drinking water Some Local to interview, many from the coastal community project resonate? positive spirit with which the Sand Motor official positions danger for actors company, years regional level later shared this view. But what made the idea behind the pilot is still regarded within the Dutch coastal of agencies or municipality, village Sand Motor so attractive for people to management community. institutions. A positive spirit around the Sand Motor get involved in positive storytelling? The shared narratives reveal how many One of the explanations is that the idea 2 As an iconic a Emerged from Dredging industry, Decades Regional to people have positive memories of the pilot comprised so many ingredients that it departure coastal defence RWS or some global level Sand Motor. The “iconic” quality of the Sand could suit everyone’s taste. At the same techniques/ decades Motor (Narrative 2) was emphasized by core time, it retained key elements like the

SAND MOTOR nourishment participants in the pilot project. For others importance of coastal safety, something PILOT techniques/ who were closely involved in the actual which is undisputed in the Netherlands. successor of the implementation and execution, the Sand Its multifunctionality provided space for Delta Works Motor was an “exciting unknown project” everyone to get involved in sharing positive (Narrative 1). The narrative that viewed the stories; it allowed people from diverse b Emerged Engineering science, Decades Regional to Sand Motor as neither an "exciting unknown organizations to endorse the unique and from knowledge RWS or some global level project” nor an “iconic departure” promising project in a way that fit their development in decades (Narrative 3), had a narrow base in the own organization. As a result, during the coastal engineering interviews with the core participants, yet decision-making process and project (closely related to it enjoyed broad support from the coastal realization, everyone could return to their above) community. own base with appropriate news. In this way, support could grow and was ensured c Emerged from Province, provincial Decades Regional to It is no coincidence that Narrative 2 was among many participating organizations. Integrated Coastal council or some global level common among core participants involved Zone Development/ decades in the earlier phase, that of the realization After the decision-making and project regional of the pilot Sand Motor. After all, these preparations, the Sand Motor was ultimately development people worked hard to communicate the constructed. The Sand Motor was and project’s unique and promising nature to is “doing well” and does indeed provide d Emerged from Village Decades Regional to make it a reality. Emphasizing the Sand multiple functions for different users. unwanted plan or some global level Motor’s “iconicity” in their personal and Critical voices seem to have faded away. development (for decades shared narrative is a logical consequence of From the moment that the peninsula was economic activities their ambition. This type of communication created, people came from far and wide which changes the could be identified early in the process. to explore and discover. The many nature- area's character) For instance, in their personal narratives related excursions, sport and cultural several interviewees portray the project activities that currently take place at the as “an impulse for the Dutch (dredging) site show how different groups have taken ? 3 As a stage in a Nourishment, Consultancy Some Regional to industry,” although they did not have any possession of the new spot. Companies an incremental not really new decades global level personal relation with this business. And (e.g., dredging firms) organize tours for process of coastal techniques, but with some actors praise the “room for natural and potential clients, as does the project team development some improvements morphological processes,” even when they of the public works agency Rijkswaterstaat, relating tender were not (primarily) concerned with this which receives guests from foreign procedures and topic themselves. government organizations, from universities ecological impact and from other educational institutions.

These traces of early-phase storytelling are So, after being subject of many (positive) – GOVERNANCE ASPECTS examples of how storytelling can resonate stories, the Sand Motor itself functions as

in such processes, generally increasing a place where experiences and stories are TWO participants’ inclination to commit created and told. 36 themselves to the process. During the pilot 37 Figure 1. Ewert Aukes Locations of Sand Motor and Hondsbossche and Pettemer Sea Defense UNDERSTANDING PROJECT SUCCESS THROUGH FRAMING CONTENT AND CAPABILITY

Ewert Aukes obtained his PhD at the The overall consensus is that the Sand disagreements and personnel changes (first department of Governance and Technology Motor has been a success. Although it is idea was raised in 2004, but construction for Sustainability at University of Twente in still too early to indicate the long-term only occurred in 2015). In this project on 2017. He currently works at the department consequences of this kind of large-scale the North Sea coast of North Holland, a of Science, Technology and Policy Studies beach nourishment, the success stories told proposed seawall reinforcement eventually at University of Twente, as a postdoctoral about the Sand Motor tend to muffle the turned into a large beach nourishment researcher. critical ones (Page 34). So, how did the Sand scheme. The evolution of the proposed HONDSBOSSCHE Motor come to be perceived as “successful”? solution coincided with changes in which Dissertation title: And does the Sand Motor’s proclaimed organization was in charge of leading the AND PETTEMER “Framing coastal squeeze: Understanding success serve as a promise for future large- project. To understand the role of framing, SEA DEFENSE the integration of Mega-nourishment scale projects using sand? As we shall see, the transition period from one proposed schemes into the Dutch coastal management “framing” can provide a valuable lens to solution to the next is especially telling. SAND MOTOR solutions repertoire: An interpretive analysis understand how this general consensus Comparing the smooth Sand Motor project of coastal management processes.” developed, and why critical stories have had and the rocky HPZ project helps us to a hard time surviving in the political debate understand how framing affects successful PhD supervisors: as well as in society. realization of large-scale projects using sand. Hans Bressers (University of Twente) Kris Lulofs (University of Twente) Generally speaking, the Sand Motor can Let us first introduce the concept of framing. be characterized as a “smooth” project. This concept assumes that interpretations of Few disagreements among actors were what happens differ from person to person so persistent as to significantly delay the and may depend on education, experience, project or even threaten its realization. This or even the organizations people belong to. meant that the Sand Motor was quickly Applied to policymaking, framing theory implemented (from the first ideas in 2006 states that actors interpret how desirable to its construction in 2011) and helped to a policy and propose solutions based on define it as a success. The province of South their “frame.” For example, one policy Holland led the Sand Motor project, which maker might recommend lowering taxes is unusual, since provincial governments to encourage consumer spending, while are not formally responsible for coastal another might argue for increase wages management in the Netherlands. However, because they are viewing the problem from a growing population and its demand for different perspectives. We will consider two space presented a pressing spatial planning aspects of framing here: the content of the issue for the province. Consequently, the frames and the actors’ framing capabilities. Sand Motor concept of a large, multi-purpose sand body went down well with the province. Content of the frames Framing content refers to the ideas actors Unfortunately, the Sand Motor is by no have about a policy situation. In coastal means a blueprint for future large-scale management, this could mean whether they coastal engineering projects. A case in point advocate a traditional “hard” engineering

is the coastal reinforcement project carried solution or an innovative “soft” one – GOVERNANCE ASPECTS out at the Hondsbossche en Pettemer (Figure 2, next page). If the goal of policy

Zeewering (HPZ) (Hondsbossche and making is that an actor is able to successfully TWO Pettemer Sea Defense, Figure 1), which took implement their proposal, being able to vary 38 more than ten years to be implemented with framing content is an advantage. Doing 39 Figure 2a and 2b. (below) Figure 3. (far below left) this allows an actor to tailor their message The actors’ framing capabilities platform and Rijkswaterstaat – and Illustration of "hard" versus "soft" The four functions of the Multifunctionality to resonate with other actors’ framing Framing capabilities include the interactive presented the project to the parliamentary engineering. The photo on the left shows frame. content. This ability played a role in both the components of framing: whom an actor forum for spatial planning projects. The the original "Hondsbossche en Pettemer HPZ project and the Sand Motor, albeit in chooses to communicate with and what province was able to gain the support Zeewering", a large dike in North Holland, Figure 4. (far below right) different ways. they choose to communicate. This strategic of these organizations as a result of the whereas the photo on the right shows Framing capabilities and the result of a use of framing depends on a sensitivity, versatility of the framing content, which the same construction fortified by sand versatile framing content. In 2006, the province of North Holland permitting actors to adjust their framing allowed them to broaden or narrow the nourishment rather than additional hard proposed reinforcing the existing HPZ with content to the frames of other actors. So, range of functions depending on whom they structures. (Photo credit: Boskalis.) an expensive traditional seawall, which framing is not something one does or does were trying to convince. Once the province would, however, have meant “sacrificing” not do. Rather, we are all able to frame found a way of framing the Sand Motor’s half a village. This proposal ignored regional effectively to a certain degree, if we are functions that resonated with another economic and demographic developments able to develop this sensitivity. In the two organization’s framing content, the added – both pressing matters in the region – and projects, different framing capabilities value would appear, and the other actors it did not create new recreational space. resulted in different outcomes. would become convinced of the project’s With its strong focus on coastal safety, usefulness. The ability to find the right the provincial government disregarded In the HPZ project, the rigid framing content tone and arguments resulted in a growing other framing contents. For actors with present in the North Holland government’s coalition of organizations supporting the other frames, the proposal would make proposal reflected a low sensitivity towards Sand Motor through its construction in 2011. the situation even worse. In other words, other actors’ framing content. The proposal framing the solution in terms of a traditional, showed insufficient understanding of other It takes a creative, daring leader monofunctional seawall reinforcement actors’ perceptions and did not include The Sand Motor project not only shows that was too limited, and was unable to adapt measures to consider these. Additionally, a versatile framing content helps an actor to to other framing contents. Omitting the rationale for the monofunctional convince others, but that these options have these other framing contents created a seawall reinforcement was not enough to be deployed skillfully to achieve an effect. rift between the provincial government to convince the Ministry of Infrastructure This may be more difficult, especially in less and other actors. The resulting political and Environment to authorize the project. experimental projects like the HPZ project, impasse was only overcome as another However, this was not only due to the where pre-existing coastal safety criteria organization gradually took over as project provincial government’s lack of sensitivity to determine the response. In such cases, it lead, and as a more versatile, large-scale other actors’ framing content, but also due requires a creative and daring project lead to sandy nourishment scheme was chosen to to the limitations of the proposed solution. move beyond pre-defined framing content reinforce the coast of North Holland. The example of the HPZ project indicates and find innovative coastal management Nature the difficulty of convincing other actors solutions that might be more suitable. development How different was the Sand Motor project! to adopt a policy solution when they have Public Works From the start, the province of South different interpretations of the problem. The Sand Motor and HPZ projects Agency Holland, which led the project, advocated developed at a time, when mega- Nature Leisure (Rijkswaterstaat) for a project which would protect the coast, The versatility of the Sand Motor provided nourishment and multifunctional schemes development enable leisure activities and encourage many more potential framing options – had received enough attention to become economic development at the beach, and the provincial government of South dominant frames in Dutch coastal while simultaneously sparking national and Holland seized these. It began by involving management. Arguably, the positive framing global interest for an unprecedented Dutch many actors in the process and trying to resulting from the Sand Motor project led Province of coastal innovation (Multifunctionality frame, understand their interests. A broad advisory to the revised, and successful, HPZ project, South Holland Municipalities Figure 3). Such an integrated vision had the board was established for the project, resulting in the Hondsbossche Duinen. The potential to get many actors on board, even including a high profile chairman and fact that large-scale projects using sand if their framing content represented only municipal delegates; this board provided such as the Sand Motor can be framed one of those elements. While some aspects, information and permitted consultation. as multifunctional makes them adaptable such as the precise location and shape of With a thorough understanding of the to a variety of frames. However, they Coastal Economic Innovation platform of the Sand Motor, were thoroughly debated, framing content of other actors, the do not frame themselves. Individuals or protection development National government its integrated design eventually facilitated provincial government began a kind organizations need to have the sensitivity a broad coalition in its favor. In the end, of “promotion tour” to advocate for its to know where and how such large-scale

the Sand Motor was not only realized proposal, much like a travelling salesman nourishments can be successfully promoted. – GOVERNANCE ASPECTS because of the versatility of its framing promoting a product at various doorsteps

Interpretive policy content (Figure 3), but also due to the (Figure 4). It visited multiple political TWO entrepreneur framing capabilities applied in the project. organizations – such as a national innovation 40 41 42 Water Authority.) Vechtstromen Almelo: Guide, Assessment Governance (2015), (Eds.) Bressers Nanny and Bressers Hans figure: (Source governance. of dimensions interrelated Five 1. Figure Scales Levels Levels & Responsibilities Resources & Networks Actors & Instruments Strategies & Perceptions Perceptions Goals & necessary to implement them. Few water projects would be be would projects water Few them. to implement necessary responsibilities different the and goals, those to achieve proposed instruments and strategies of variety the to recognize we need that means also “administration” or “policy” than rather governance of terms in Thinking contradictory. sometimes are goals these result, a As compromises. often are they –and stake at are issues core what of perceptions different on depend can Goals these. achieve ways to and goals multiple identifying means governance Analyzing actors. of interplay such of acase clearly was Motor Sand The them. opposing– sometimes –and steering in involved actively but decisions, of object the just not is sector the governance, multi-actor In sectors. within stakeholders includes often and non-governmental, and governmental both actors, many of interplay the maker.” involves It “decision actor, the one for concern a just not is issue a given that means governance Multi-actor coastline. Dutch the of much to serve intended explicitly measure local avery of example agreat is itself Motor Sand The levels. decision-making the for true just not was that Motor Sand the of case the In aligned. well are involved levels various the that sure to make useful more is it Instead, things. to arrange level “best” the for to look sense national (e.g., simultaneously levels multiple at but municipal, or national instance for level, asingle at with dealt not is issue agiven that means governance Multi-level governance.” “multi-actor and governance” “multi-level terms the in studies policy in used first was “governance” term The questions. governance ways to approach other are there course, Of 34). (Page project whole the understand to used stakeholders which storylines the 30), and (Page case actual the to interpret stakeholders guided that frames the points: starting related but different, from issue the approached researchers Motor. The Sand pilot to the up leading process decision-making the of dynamics the into insights many provided that a quest on Bontje Lotte and Aukes Ewert researchers led question intriguing This about. came Motor Sand the how with deals chapter This Motor. Sand pilot the of aspects governance the on focused which S6, project research scientific for Investigator Principal the was he NatureCoast, Twente. of Within University at the Policy Environmental and Studies Policy of aprofessor is Bressers Hans REFLECTION STORYLINE AND FRAME SUPPORTING A AS MULTIFUNCTIONALITY Hans Bressers and municipal). It rarely makes makes rarely It municipal). but an extremely successful one with a bright future. future. abright with one successful extremely an but solutions, nature-based for aframe just not is Nature with Building that by saying conclude can One measures. adaptation to climate linked inland, further applications for attention attracting also is concept the Finally, 187). 3and (see Pages Nieboer Henk EcoShape, of director the and Ovink, Henk affairs, water international envoy for special Dutch by the paper aposition in supported strongly was Nature with Building of concept the Water 2018, Day World On resilience. and goals development sustainable growth, green economy, circular Water report its of core the at philosophy this placed Nations United the recently, More 2011. in term the embraced also Infrastructure Transport Waterborne for Association World The nature.” with “working as it promoting mid-2000s, the in idea Nature with Building the adopted already Union European The expanding. vastly and quickly rather been has use its of realm The options. innovative and new towards minds stakeholders’ many opened has that one acompelling to be proven has this it– and fighting than rather nature with –aligning same the remains idea basic the time, over change might name the While itself. frame and storyline apowerful as Nature” with “Building of idea basic the view but help cannot one storylines, and frames like concepts of usefulness the Considering house.” governance the of “rooms the all considering for point astarting provided has but studies, the limited not has perceptions on emphasis the words, other In resources. and responsibilities, strategies, potential actors, scales, various to integrate possible it made multifunctionality how show also studies but pilot, Motor Sand the in included were that goals multiple to the refers Multifunctionality project. the for aframe and storyline asupportive both as “multifunctionality” of importance the is Akey result “perceptions.” of view of point the from governance approached project NatureCoast the of Studies process. acomplex making decision and governance make and interrelated interdependent, are governance of key elements the 1, Figure in illustrated As administrative. and financial both resources, pooling without Netherlands the in feasible (2018), connecting it to other “framing buzzwords,” such as as such buzzwords,” “framing to it other connecting (2018), Nature-based Solutions for for Solutions Nature-based 43 TWO – GOVERNANCE JANUARY 2012 Program director of the Sand Motor HANS KLEIJ – PROVINCE OF SOUTH HOLLAND

INTERVIEW

In what way is the Sand Motor unique to Of course, we cannot predict everything, in charge of enforcement for the province you end-user? but most sand transport will function in the of South Holland. We regularly had to close “It is unique to us because it has enabled intended way, namely to strengthen the the beach during the high season, because us to achieve three things at once. First, coastal foundation." And it was mainly this these nourishments created dangerous long-term coastal reinforcement. Second, scientific foundation that made society and situations in which people could drown. That it was a large contribution to the amount of politicians feel good about the Sand Motor; is another advantage of the Sand Motor: recreational area in the southern part of the we could explain the effects of 21.5 million it deposits every grain of sand where it Randstad. We had a deficit of some 40,000 cubic meters of sand deposited at once. should naturally be, through the principle hectares of green space compared to similar Later on, when we had to appear before a of Building with Nature, via all the laws of regions such as London, Paris and even the committee, we could also respond to their nature.” Ruhr area in Germany. And third, we were questions with the help of scientific insights. also able to show something innovative, Science was indispensable to us throughout How important was the understanding applying the principle of Building with the process.” of each other's stories and ideas for the Nature, and with all PhD candidates who development of the Sand Motor? studied the Sand Motor. This gives us How relevant is multidisciplinary research "This is a very important aspect, because a knowledge advantage over other on the Sand Motor for you as end-user? everyone operates from their own countries; they might be able to dredge “Multidisciplinary knowledge is invaluable for perspective, visions and dogmas. We more cheaply, but we know more about the achieving the multiple goals set by the Sand engaged in intensive dialogues with all overall consequences and driving forces of Motor consortium. When the Sand Motor the different parties to understand their mega nourishments.” was in place, we started the NatureCoast perspective. And sure, it is multidisciplinary program with the NWO. All these young and everyone can have an opinion, but How do you see the role of scientific people have produced great research, the process must also be managed. Lotte research at the Sand Motor? which in turn positions the Netherlands in Bontje, Ewert Aukes and Vera Vikolainen "I found that scientific research created the forefront of hydraulic engineering. The conducted this research, which clearly trust in the concept behind the Sand multidisciplinary approach of NatureCoast showed how different the stories of different Motor. Many parties were against it when ensured that not only was technology stakeholders were. The fact that you know we had just started. They were afraid that taken into account, but also ecology and and understand each other's stories has things might go wrong, swimmer safety governance: how do you tackle these kinds brought important insights, but these would be at stake, and they argued that of processes, who are the stakeholders, why differences also required guidance in terms the current nourishments worked well do you encounter resistance and who can of governance. In the end, things have to be anyway, and so on. But the scientists, who help you? The combination of all disciplines concluded and decided, and I would argue were represented in all kinds of groups, made the project a success.” that gaining those insights contributed to could give a considered response to these the success of the Sand Motor.” objections. For example, a number of Delft What are the main findings of the University of Technology professors were NatureCoast program for you as end-user? part of the steering committee: Marcel Stive “What I got out of it, besides all kinds and Huib de Vriend. And Suzanne Hulscher of technical aspects, is that this way of of the University of Twente took part in the carrying out coastal maintenance is much innovation platform, chaired at the time by more cost-effective than the way we used to

Prime Minister Balkenende. Those experts organize this in the Netherlands. In the past, – GOVERNANCE ASPECTS could tell the scientific story: "If we put Rijkswaterstaat placed small quantities of

the Sand Motor at that specific location at sand along the entire coast to nourish that TWO Ter Heijde, then we will really get a sediment coast. This had all kinds of effects, including 44 flow to the north and to the south. the occurrence of quicksand. I used to be 45 JULY 2012 Advisor and specialist in chemical, environmental and civil engineering RONALD WATERMAN – PROVINCE OF SOUTH HOLLAND

INTERVIEW

In what way is the Sand Motor unique and the surrounding environment. The What does the Sand Motor mean for the for you? latter means citizens, NGOs, and nature, future of sandy solutions or Building with “The Sand Motor is not unique within the environment and landscape in general. All Nature? Building with Nature idea. Building with five aspects need to be considered if we “In itself, the Sand Motor has an important Nature as a concept started in 1980, first are to achieve our objective of creating the function as an icon, because it has with the van Dixhoorn triangle at Hoek van project and sharing the knowledge gained generated enormous attention. It is a Holland, followed by the Slufterdam, the in making it. In this respect, education and special "baby" in the series of Dutch coastal Maasvlakte II, the widening of the Delfland research are the focal points for science.” developments. But in my opinion, we coast, Seaport Marina IJmuiden, and need to look beyond the Sand Motor and Kennemerstrand and Kennemermeer. After How relevant is multidisciplinary research consider the entire range of Building with them came the Sand Motor, followed by on the Sand Motor? Nature projects so that we can export our other projects. The Sand Motor is just one “The whole family of Building with Nature knowledge and apply it abroad. I am raising star in that constellation; and, compared solutions requires an integrated and this issue now, because this is not mentioned to the other projects, the one that is most multifunctional approach, and that means frequently enough!” difficult to export commercially or apply in multidisciplinary research. This is necessary other places.” to provide an answer to the question "How can we arrive at weighted and sustainable “What is unique about the Sand Motor, solutions for existing and future problems, however, is that it assumes that the while creating added value?" While doing so, coastline is not an equilibrium line at the we also need to investigate the relationships beginning, but strives for it in the long term. between problems, how they relate to the All the other plans have tried to create an hinterland and to the adjacent lakes, rivers immediate dynamic equilibrium, where or sea. In my experience, applying the erosion and accretion are approximately in Building with Nature concept is not enough. balance, with low maintenance and with a I have therefore already developed the new minimum of hard, defensive elements. The concept, "Aquapuncture", which aims to uniqueness of the Sand Motor is the process. revitalize waterways and their waterfronts. Furthermore, it is very interesting as a pilot, I believe this will become just as important and as a way to generate knowledge about as Building with Nature!" sediment transport, dune formation, the emergence of pioneer plants, wind transport What are the main findings of the of sand, and so forth.” NatureCoast program in your eyes? “NatureCoast's research contributes to an How do you see the role of scientific enormous challenge: 80% of the world’s research at the Sand Motor, as end-user? largest population concentrations are “I see scientific research as important for located along coasts or in delta areas. the Sand Motor, but that also applies to This makes it imperative that we develop all the other projects that were initiated answers to questions about scarcity of by Building with Nature. In fact, these space for living, working and recreating,

projects always have to deal with what I call and the infrastructure needed to support – GOVERNANCE ASPECTS the 5 O's in Dutch (overheden, onderwijs, this. And all of this combined with the

onderzoek, ondernemingen and omgeving): vulnerability of this infrastructure to climate TWO the authorities, education, research, private change. Although NatureCoast's research 46 companies (both consultants and dredgers) has contributed, much remains to be done.” 47 THREE | PHYSICAL SYSTEM – PHYSICAL SYSTEM THREE

48 49 Arjen Luijendijk IMPACT ON PHYSICAL CHARACTERISTICS

Town of Ter Heijde INTRODUCTION

The Sand Motor is located at the Delfland coast between the the spreading caused by the natural forces of tides, waves and wind Argus video tower entrances of Scheveningen and Rotterdam harbors. This southern resulted in a fascinating evolution of the bathymetry and topography. Dune lake part of the Dutch coast is subject to structural erosion; the In particular, this chapter presents the unique setup and output of a coastline migrated landwards about 1 km between 1600 and 1990. multidisciplinary field campaign called MEGAPEX2014 (Page 74). After the coast retreated about 300 m in the 18th century, rubble mound groins were constructed. As the coastline continued to The placement of the large-scale nourishment has significantly Head erode despite the groins, sand nourishments were introduced as changed the tidal and wave-driven currents at the Sand Motor a mitigation measure in the 1970s. Since then, nourishments have and beyond. Extensive drifter experiments have revealed large- been implemented more frequently, especially after the Dynamic scale eddies around the Sand Motor. Max Radermacher shows how Lagoon Preservation Act of 1990 dictated that the 1990 coastline position the changes in the tidal currents and the continuously changing had to be maintained at all costs. The first nourishment at the site of bathymetry affect the day-to-day assessment of swimmer safety the Sand Motor occurred in 1986. Since then, the coastline was (Page 54). re-nourished eight times prior to the construction of the Sand Motor. In total, approximately 55 million m3 of sand was added to the Jantien Rutten illustrates that the interaction of the bathymetry with Delfland coast up to 2011, to mitigate erosion and reclaim land, with the incoming waves resulted in a dynamic bar system at the Sand a new nourishment on average every 3 – 5 years. In the last years, Motor with sandbars and rips forming and reshaping (Page 58). Dunes the nourishment volumes in this stretch of coastline reached Remote sensing techniques were used to capture this behavior in all ~1.7 million m3 per year. seasons. We show that the bar dynamics make it difficult to predict the hazardous currents around the Sand Motor. In this chapter we will discuss the impact the Sand Motor has had on the various physical processes interacting with the sand Extensive field measurements show that the currents around the nourishment. Some of these physical processes have caused the Sand Motor deposited finer sand in deeper waters, while the sand Solleveld sand to spread along the coast, reducing the initial size of the at the erosive head of the Sand Motor coarsened considerably disturbance and hence the impact over time. For a comprehensive over time. Bas Huisman (Page 62) explains why, how and when this understanding of the behavior of the Sand Motor we have sediment sorting takes place. The numerical modeling that helps adopted a multidisciplinary approach to study all relevant aspects. us understand this phenomena also allows us to make advanced We will discuss the drivers that have shaped the Sand Motor forecasts of how the Sand Motor will evolve. between 2011 and 2018: i.e., the tidal currents, waves, wind, and sediment transport. In addition, we will look at the processes that The placement of the Sand Motor had large effects on the fresh Channel are influenced by the changing Sand Motor, like the hydrology groundwater resources. Sebastian Huizer illustrates that this turned (freshwater reservoir) and geochemistry (chemical properties of out to be strongly related to the tides, waves and the spreading of Spit the sand). the Sand Motor (Page 66). Beach Restaurants First, we will look at the observed behavior of the Sand Motor since Iris Pit dives into the biogeochemical properties of the sediment its creation. In the next section (Page 53) we will look at the design which became exposed to the atmospheric conditions after and the rapid construction of the Sand Motor in 2011. We show that placement (Page 70). We show that the variation in iron content and carbonate minerals found in the offshore-dredged sand originates from two different geological layers in the sand mining area. The

environmental risks associated with the sediments used for the Sand – PHYSICAL SYSTEM Photo (left page): Motor will be compared to other beach nourishments. Naming the key

elements of the Finally, principle investigator Gerben Ruessink reflects on the THREE Sand Motor coastal chapter’s findings and the implications for present and future 50 area. coastal management (Page 74). 51 Figure 1. Arjen Luijendijk Compilation of measured bed levels in the period 2011 – 2018, carried out by Shore Monitoring & Research. OBSERVED BEHAVIOR IN A NUTSHELL

Construction survey jetski, GPS on a wheeled pole and a more often, are thus almost as important The pilot Sand Motor involved constructing quad bike. These bed level measurements to the erosion of the Sand Motor as storm a large peninsula of about 2 km alongshore, show a rapid, predominantly alongshore conditions. with the most seaward position protruding redistribution of sediment in the first about 1 km into the sea. The main part is year after construction. The head of The Sand Motor can be seen as a sand a hook-shaped peninsula with the outer the peninsula eroded rapidly, leading to sorting machine. At the seaward part of tip curved towards the north. The crest of accretion both to the north and south. In the peninsula, we found much larger sand August 2011 February 2014 September 2016 the peninsula rises to 5 m above mean sea the first half year after implementation, a diameters than those initially placed, with level. This design and location best fulfilled spit developed from the northern tip of the sediment diameters up to 540 µm. During the multidisciplinary and multi-stakeholder peninsula, pinching the lagoon entrance erosion events, the fine sand particles are requirements of safety in combination with (see photo on Page 50). The maximum washed out and transported away, while the recreation, development of nature, and elevation of the spit and shoal were slightly larger sand particles remain behind, as the scientific innovation. The cross-shore slope below the high water level, so they flooded seabed is lowered. The eroded finer sand of the peninsula is 1:50, so that the toe of during high tide (and storms). The channel particles are deposited in areas northeast the nourishment is at -8 m NAP and ~1500 m landward of the shoal discharged the flow and southwest of the head of the Sand from the original coastline. The northern into and from the lagoon. This resulted in Motor, forming patches of fine sand at water February 2012 August 2014 August 2017 tip of the peninsula creates a sheltered area strong flow velocities of over 1 m/s during depths of 8 – 12 m. How these patches that nurtures different biotic species. rising and falling tide in the spring of 2012, are relevant for marine ecology will be A small lake of about 8 hectares was causing hazardous situations for swimmers discussed in Chapter 5. In the longer term, designed to prevent the freshwater lens in (Page 55). In the first three years, the this coarsening of sand at the head of the the dunes from migrating seaward, which coastline developed into a Gaussian bell Sand Motor may affect its overall shape and would endanger groundwater extraction shaped curve. The curve widened over time, the rate of change. from the existing dune area. although after 2015 no further widening of the shoreline position was observed. In the first year after construction, the Sand Sediment for the nourishment was mined Since 2016, the shoreline has developed an Motor changed shape faster than expected August 2012 February 2015 January 2018 offshore at two sites just beyond the 20 m asymmetrical shape. based on long-term model calculations depth contour at a distance of about 9 km. performed as part of the environmental The sand was mined by Trailing Hopper Although no sub-tidal bars were present impact assessment. Conversely, subsequent Suction Dredgers and placed at the Sand after construction, these sand bars started changes were slower than predicted. In Motor location by a combination of dumping to develop after about a year. The sub- 2018, the head of the Sand Motor had through the doors in the hull, rainbowing tidal bars and coastline position seem to retreated about 300 meters since its (Page 14), and pumping onto the beach. have been linked since 2013. Storms can creation in 2011. At the same time, the Sand The Sand Motor was constructed between sometimes cause a large-scale reset of the Motor extended up to 6 km alongshore. This March and July 2011 (page 186 shows a bar system (Page 59). shows that the intended feeder function February 2013 August 2015 August 2018 compilation of aerial images during the works well. The adjacent beaches are construction phase). Grain size analysis By 2018, about 3.5 million m3 of sand had gradually fed by the Sand Motor as the

revealed the mean sediment diameter D50 left the initial peninsula area. The erosion sand is spread by natural forces. Both data Bed level (m w.r.t. MSL) was circa 280 µm, which is slightly larger of the peninsula is predominantly caused extrapolation and recent modeling suggest

than the mean sediment sizes found at the by wave action, and where both daily that the lifetime of the Sand Motor will easily – PHYSICAL SYSTEM natural coast here (250 µm). conditions and high wave events matter. exceed twenty years and could be as much -12-11-10-9-8-7-6-5-4-3-2-1 0 1 2 3 4 5 6 7 Analysis shows that the 12 largest wave as 40 - 50 years.

Evolution events of the first year resulted in about THREE Monthly surveys have measured the 60% of the total erosion observed in that 52 August 2013 February 2016 bathymetry and topography using a year. Milder wave conditions, which occur 53 Figure 1. Max Radermacher Aerial image of the Sand Motor just after construction. THE IMPACT OF LARGE-SCALE NOURISHMENTS ON The sediment clouds at the water surface NEARSHORE HYDRODYNAMICS clearly show the presence of a tidal eddy as a result of flow separation. Max Radermacher obtained his PhD From a physical perspective, the Sand Sea coast, running from south to north at the Faculty of Civil Engineering and Motor is a large, protruding body of sand during the flood stage and from north to Geosciences, section of Coastal Engineering, along the Delfland coast. Modifying the south during ebb. These tidal currents can at Delft University of Technology in 2018. coast on a kilometer-scale inherently has reach peak velocities up to 1 m/s near the Max is the founder of WaveDroid, a start-up an effect on coastal hydrodynamics, which head of the Sand Motor. The Sand Motor company that has developed an innovative, involve currents and surface waves. These acts as a large-scale perturbation to the low-cost, light-weight wave measurement will behave differently due to the presence tidal currents, forcing them to contract buoy. of the Sand Motor. In turn, the modified around the head of the nourishment (the nearshore hydrodynamics will influence most seaward point). On the downstream Dissertation title: the morphological development of the side of the head, the flow cannot follow the “Impact of sand nourishments on Sand Motor. strongly curved coastline. The tidal current hydrodynamics and swimmer safety.” is diverted offshore, creating a large-scale Apart from their role in morphodynamics, tidal eddy adjacent to the nourishment. We PhD supervisors: the altered hydrodynamics around a observed this phenomenon at the Sand Marcel Stive (Delft University of Technology) nourishment may also affect recreational Motor in 2014 during the MEGAPEX2014 Ad Reniers (Delft University of Technology) safety. The Sand Motor has been measurement campaign (Page 74). Matthieu de Schipper (Delft University of constructed to stimulate many different The generated tidal eddy had a diameter Technology) functions of the coastal zone, one of them of more than one kilometer and extended being recreation. Although absolute safety further offshore than the tip of the can never be guaranteed when designing nourishment (Figure 2). coastal engineering works, a negative impact on swimmer safety is generally These tidal eddies were also predicted by considered unwanted and unacceptable. our computer model of the Sand Motor. Shoreline 1 m/s Due to the unprecedented character By changing the size and shape of the -10m contour 2000 of the Sand Motor, its exact impact on nourishment in the model, we determined Ship hydrodynamics, morphodynamics and which nourishment designs would lead 1500 Fixed swimmer safety was difficult to predict to the formation of eddies. Because of its ahead of time. Therefore, our research morphodynamic evolution, the Sand Motor 1000

y [m] aimed to determine and understand changes shape continuously. This means

500 the ways in which a large-scale beach that its effect on the tidal currents will nourishment can affect nearshore also change over time. As the Sand Motor 0 16:30 17:30 18:30 hydrodynamics and swimmer safety. retreats and becomes more “streamlined”, Three different flow phenomena were the tidal currents will eventually stop Figure 2. identified which are directly or indirectly separating and eddies will no longer be Measurements of caused by the Sand Motor: tidal eddy formed. Our computer model predicts that current velocities 2000 formation, rip currents, and tidal dynamics this transition occurred in 2015, although during several around the artificial lagoon. All three will be a new measurement campaign would be 1500 phases of the discussed here. needed to validate this.

tide showing the – PHYSICAL SYSTEM 1000 development of a y [m] Tidal eddy formation At certain moments in the tide, these eddies tidal eddy during 500 First of all, the Sand Motor can cause tidal can cause offshore-directed currents around

flood currents at currents to separate and generate new tidal the tip of the Sand Motor. These offshore THREE the northern side 0 19:30 20:30 21:30 eddies (Figure 1). Relatively strong tidal currents may be hazardous to swimmers, 54 of the Sand Motor. currents are present along the Dutch North as the currents can carry swimmers away 55 -1000 -500 0 500 1000 1500 2000 -1000 -500 0 500 1000 1500 2000 -1000 -500 0 500 1000 1500 2000 x [m] x [m] x [m] Figure 3. 500 Bed level from the beach. These eddies can also the channel about one year after the Sand waves breaking on subtidal sandbars, which Morphological affect the morphodynamic evolution of Motor was constructed. is not likely to occur during pleasant weather evolution of the -5 0 5 10 m the nourishment. In particular, they can conditions. Hence, the risk of rip currents to Sand Motor lagoon 0 influence the spatial distribution of sediment As the morphodynamic evolution continued, swimmer safety is also relatively small. and its entrance grain sizes, which is treated in more detail the channel became even narrower and channel between y [m] from Page 62. longer, constricting the amount of water This leaves tidal dynamics in the Sand

March 2012 and -500 that could flow out of the lagoon at low Motor lagoon as the single largest risk March 2016. Due to Rip current generation tide. Therefore, the tidal range in the for swimmers. Tidal currents in the ongoing alongshore Mar 2012 Rip currents are fast-flowing currents close lagoon gradually became smaller and the entrance channel occur on a regular basis, spreading of the to the beach that are directed offshore. average water level rose. This reduced determined by the tides, regardless of the nourishment, the These currents are generated when waves the tidal currents in the entrance channel, weather conditions. In addition, beach users channel gradually 500 break on nearshore sandbars. The risk of significantly lowering the associated risk to tend to cluster around the entrance channel became narrower rip currents is especially large when the swimmers. near Kijkduin on crowded beach days. and longer. Tidal sandbars are interrupted by small channels. Nevertheless, it should be noted that the currents in the 0 Because they can carry swimmers away Swimmer safety risks related to tidal currents in the entrance channel were from the beach, rip currents are a serious The actual swimmer safety at a beach channel strongly depend on the channel’s strongest in 2012. y [m] hazard for coastal swimmers worldwide. depends on more than the local nearshore morphological evolution. At the Sand Motor,

-500 Although sandbars and rip currents are a hydrodynamics. The presence of beach the risk was high in the first years after its natural part of the coastal environment, the users and their distribution over space construction, but has gradually diminished Jun 2015 construction of a large-scale intervention and time are equally important. In order to over the years. can stimulate the formation of the formation determine the risk to swimmer safety at the of sandbars and rip channels along the Sand Motor, we have therefore assessed 500 coast. how hazardous hydrodynamic phenomena coincide with the presence of beach users. At the Delfland coast, we found that 0 the spatial variability of sandbars (and At the Sand Motor, the spatial spreading therefore the potential for rip currents) of beach users is strongly linked to the y [m] clearly increased between 2009 and 2012. availability of beach facilities (Figure 4).

-500 Not only was the Sand Motor constructed Most beach entrances, restaurants and during this period, but the entire Delfland parking facilities are clustered around the Mar 2016 coast was reinforced with several large coastal towns of Kijkduin and Ter Heijde. -2500 -2000 -1500 -1000 -500 0 500 1000 1500 2000 beach nourishments. The new sand from Beach users therefore tend to cluster at x [m] the nourishment covered the relatively the beaches in front of these two towns, deep and straight sandbars that were around the outer edges of the Sand there before. After the nourishments, new, Motor. Beach use at the central part of the shallow sandbars formed, which became nourishment is very low. As a result, the highly variable over time. The evolution of risk posed by currents related to the tidal sandbars and sandbar variability at the Sand eddies is relatively small. These currents Motor itself is treated in more detail from (directed offshore) occur around the tip of Figure 4. Page 58. the Sand Motor, where hardly any beach Distribution of beach BeachBeach restaurantrestaurant users are present. In contrast, the other two facilities around the HolidayHoliday residence Tidal dynamics in the lagoon hazardous phenomena (rip currents and Sand Motor has an CarCar parking parking 1 km While the artificial lagoon is largely tidal dynamics in the lagoon) occur in areas important influence CoastalCoastal towntown sheltered from wave action, the water level that receive significantly higher numbers of on the spreading of BeachBeach entranceentrance inside the lagoon moves up and down beach users. beach users. Map with the tide in the North Sea. This leads shows locations of to tidal currents in the channel connecting The spreading of beach users over time coastal towns of the lagoon to the open sea. Initially, the is strongly linked to the weather. Suitable

Ter Heijde (left) and lagoon’s entrance channel was very wide, weather for a beach visit are days with high – PHYSICAL SYSTEM Kijkduin (right). leading to low tidal flow velocities. However, temperature, no clouds, no rain and weak with the morphodynamic evolution of the wind. Since waves at the Dutch North Sea

nourishment, the channel became narrower coast are typically generated by local winds, THREE (Figure 3). This squeezed the tidal current, the wave height tends to be low on popular 56 leading to a strong and hazardous current in beach days. Most rip currents are formed by 57 Figure 1. (below top) with a pronounced pattern (northern side, Jantien Rutten Ten-minute averaged top-view video images top panel; western side, bottom panel). at the Sand Motor. The white line indicates Alongshore differences in geometry are also the position of the sandbar (outer line) apparent, such as the alongshore wavelength THE IMPACT OF THE SAND MOTOR ON SANDBAR BEHAVIOR and the shoreline (inner line). Alongshore of the patterns and the distance between the differences in patterning can be observed: sandbar and the shoreline. a straight sandbar (western side, top panel; northern side, bottom panel) and a sandbar

Jantien Rutten obtained her PhD at the Since the Sand Motor was completed in coasts with a slight curvature (embayed Department of Physical Geography, Faculty July 2011, the nourishment itself has been beaches). They barely addressed the spatial of Geosciences at Utrecht University, in losing sand, whereas adjacent beaches have variability in sandbar behavior, which is 2018. She currenty works as a postdoc at been gaining sand. This large-scale expected to occur along curved coasts as Universidad Nacional Autónoma de Mexico (O(1000 m)) evolution at decadal timescales they impose alongshore variations in wave (Instituto de Ingeniería). was intended, and was predicted by energy and wave angle. The question how numerical models (as will be discussed in bar behavior is exactly affected by a curved Dissertation title: detail on Page 145). How the morphology coast became highly relevant with the "Sandbar behavior along a man-made would change at meso-scales (O(100 m)) construction of the Sand Motor. With similar curved coast." on daily and seasonal timescales was largely concentrated, kilometer-scale nourishments unknown at the moment of construction. expected elsewhere, we need to fully PhD supervisors: Surveys of the seabed in the first months understand sandbar behavior along curved Gerben Ruessink (Utrecht University) after construction showed morphologic coasts. Timothy Price (Utrecht University) features developing at these scales. A small subtidal sandbar formed, while the cross- To investigate how sandbars behave shore profile of the nourishment changed at the Sand Motor, frequent (hourly) from a convex shape with a steep slope measurements are needed with large spatial towards a concave one with a milder slope. coverage (km2), but at a limited cost. X-band radar and optical video are commonly Sandbars are ridges of sand nearly parallel used to collect such data (Figure 2). These to the shore, located below the sea surface techniques record the sea surface. The wave for at least part of the tidal cycle. Sandbars pattern in the resulting recordings tells us are one of the most dynamic morphological about the underlying morphology, such features in the nearshore zone at daily as seabed elevation and sandbar position. to interannual time scales. In response Subsequently, a morphodynamic model can to wave forcing, sandbars can migrate show us the mechanisms underlying the towards the shore as well as away. When observed sandbar behavior. Figure 2. migrating onshore, sandbars may develop X-band radar station a characteristic pattern, often with some Morphological data (left) and Argus rhythmicity (Figure 1, northern side). On The elevation of the seabed can be deduced video tower (right) the other hand, when migrating offshore, from the propagation speed of the waves at the Sand Motor. existing patterns are often destroyed, via a smart algorithm. Several algorithms resulting in a straight sandbar (Figure 1, have been developed in recent decades, western side). Bars with a pronounced providing bed elevations with different pattern are associated with strong flows accuracies. They mainly differ in the method moving offshore, which are potentially for retrieving the propagation speed and the dangerous to swimmers (rip currents; relationship between propagation speed, Page 55). Therefore, understanding sandbar water depth and bed elevation. We derived

behavior is essential for swimmer safety. bed elevations at the Sand Motor using two – PHYSICAL SYSTEM algorithms, which use the same relationship Earlier studies showed that variations in (linear dispersion relation) but differ in

the wave energy and the wave angle can the method for retrieving the propagation THREE explain sandbar behavior. These studies speed: The FFT method was used with 58 were mostly based on straight coasts or X-band radar data, and the cross-spectral 59 Figure 3. method with optical video data. An accuracy Patterns were destroyed when high and occurrence of rip currents may 00 Bed elevations 0 assessment reveals that both methods have waves approached the coast obliquely. increase when a concentrated, kilometer- z derived from a systematic bias: bed elevations being too This occurred three times at the northern scale nourishment is constructed. Since b -2 X-band radar (left) -2 shallow at large depths and too deep at side, but only once at the western side. To rip currents can be a serious hazard to and optical video -2 shallow depths (Figure 3). This bias hampers summarize, timing differences in pattern swimmers, we recommend carefully -4 -2 data (right) (vertical -4 us from accurately quantifying changes in formation and destruction were observed considering the location and coastline

axes), against in MSL] sandbar position, geometry and shape at along the curved coast of the Sand curvature of large-scale nourishments at MSL] situ (surveyed) -6 -4 daily to seasonal timescales, and therefore Motor, which seem to relate to alongshore sites where beach recreation is important. [m -4 [m [m MSL] [m elevations MSL] [m we conclude that both methods seem still differences in the local wave angle. The (horizontal axis). -8 S insufficient. However, as an alternative, importance of the wave angle in the

FFT -8

The gray shading deoC -6 breaker lines in time-averaged optical formation and destruction of patterns is video CS dar radar FFT -6 vi z z ra indicates the -10-10 z images can be used, as they approximate consistent with earlier studies of straight number of data z the position of the sandbar (Figure 1). At coasts. The geometric differences between points, whereas -12-12 -8 the Sand Motor, sandbar positions were the sides (wavelength of patterns, bar crest the red error bars identified with ~10 m accuracy using time- depth, and distance to the shore) seem indicate the root- -14-14 (a) (b) averaged low-tide video images, consistent to relate to alongshore differences in the mean-square error. -10 with earlier studies. local wave height at breaking due to wave -14 -12 -10 -8-8 -6 -4 -2 0 -10-10 -8 -6 -4 -2-2 0 refraction. Sandbar observations at the Sand Motor zinsituzin situ [m MSL] zinsituzin situ [m MSL]MSL] Applying the latter method, breaker lines Mechanism of pattern formation were extracted from a 2.4-year data set A morphodynamic model was used to 0 of time-averaged video images, providing unravel the mechanism behind the formation Figure 4. data on the position and pattern of the of sandbar patterns along a curved Predicted bed sandbar on a daily basis. Bathymetric coast. We systematically explored which

elevation zb surveys provided data on the shape and conditions promoted pattern formation,

-5 [m]

after 20 days for b depth of the sandbars on a bimonthly basis. using a setup loosely based on observations z four different X [m] The image data reveal that the sandbar at the Sand Motor. The passage of storms combinations of migrated onshore in spring and summer and was schematized by a wave forcing with wave angles. The -10 offshore in the winter months, at both the a wave angle that shifted between two time-varying wave northerly and westerly exposed coast of directions every day. Our simulations angle is indicated by the Sand Motor. This migration is associated showed that the alongshore position of the circles in the top with seasonally varying wave energy. patterns, as well as their growth rate, vary left corner. Some differences were found between the with the local wave angle at breaking, i.e., northern and western side in the depth the breaker angle (Figure 4). The local X [m] of the bar crest and its distance from the breaker angle depends on the offshore shoreline, as well as in the patterns that wave angle and the local orientation of the formed and were destroyed (Figure 1). coastline. When the breaker angle increases, At the northern side, the patterns had patterns form at a lower rate or not at all. alongshore wavelengths of 200 m and Under such angles, a strong alongshore formed in spring under low-energy waves current is generated, which slows down or that approached perpendicular to the coast even inhibits pattern formation. Moreover,

X [m] (Figure 1, top panel). At the western side, the local wave height reduces because patterns with wavelengths of 400-500 m of wave refraction over the curved depth formed in autumn under moderate to high- contours. In addition, this slows down energy waves, associated with a series of pattern formation. Simulations suggest storms (Figure 1, bottom panel). Given that that patterns along a curved coast may storms pass through the North Sea basin develop faster than along straight coasts in from south to north, the direction of the wave climates wherein the coastline curve

waves gradually changed from southwest to decreases the local breaker angles. – PHYSICAL SYSTEM X [m] northwest with every storm. Consequently, waves approached near-perpendicularly at The relatively high growth rate of patterns

Y [m] the western side and highly obliquely at the at a strongly curved coast under certain THREE 1000 m northern side. wave climates implies that the strength 60 61 Figure 2. Bas Huisman Overview of sieve samples. (Photos by Laurens Bart) DYNAMICS OF THE SAND PARTICLES

Bas Huisman will obtain his PhD at the Tide and waves redistribute sediment that sieved in the laboratory (Figure 2). This Faculty of Civil Engineering and Geosciences is placed at the coast. This holds especially resulted in half-yearly maps of the typical at Delft University of Technology. His for a large-scale nourishment like the Sand grain size (i.e., median sediment diameter

research fits in with the applied research Motor. However, not all of these sand grains D50) before, during and after construction of at Deltares, which focuses on hydraulics, are transported at the same pace. Fine the Sand Motor. sediment dynamics and safety of rivers, grains typically move much faster than the deltas and seas. coarse grains, but the dynamics of sand The overview maps of the typical median particles along exposed beaches are not well grain size show that before construction (Tentative) dissertation title: understood. Some studies have even argued of the Sand Motor, the sand was coarse "On the redistribution and sorting of sand at that the coarser grains are more exposed to in shallow water, gradually getting finer nourishments." the flow and therefore more easily picked in deeper water (Figure 3). The post- up than the fine grains. As most of these construction surveys at the Sand Motor, Supervisors: studies took place in a laboratory, it would however, show a much coarser bed in front

Marcel Stive (Delft University of Technology) be useful to see evidence of this behavior in of the nourishment (the D50 is twice as large Gerben Ruessink (Utrecht University) the field. If the fine and coarse sand grains in the red area in Figure 4 compared to the Matthieu de Schipper (Delft University of move differently, then areas with a coarser pre-construction situation). Interestingly, Technology) or finer bed composition will develop, as this coarser bed is especially present in sand is removed from some regions and intermediate to deep water where the accumulates in others. In this sense, the influence of waves and wave-driven currents Figure 1. Sand Motor can be seen as a big sand- is smaller. This was not expected, since Sediment sampling sorting machine, which can provide us with largest bed changes generally take place in at a small boat fundamental understanding of the dynamics the zone with the waves. At the same time, of sand grains. Such knowledge is essential a region with fine sediment also developed if we are to protect and manage the coast just north and south of the Sand Motor. in the future. This is particularly important Finer sand was apparently moved from the to manage and protect fish populations, Sand Motor to the adjacent coast. Waves are since changes in the composition of the not likely to be responsible for this, because sandy bed affect their habitat. For example, changes are strongest outside the zone with juvenile flatfish are known to favor the fine the most wave action, and a considerably sand over coarser sand, since they can more finer bed was found after a storm event in easily hide from predators (Page 119). October 2014, rather than a coarsening. We believe that the more energetic waves To understand the actual situation at the remove part of the coarser sand layer at the seabed, we went to the Sand Motor and Sand Motor. took samples of sand from the top-layer of the bed. These samples were collected In practice it will be useful to be able to with a grab sampler operated from a small predict and evaluate the effects of large- boat (Figure 1). Accurate navigation and scale nourishments before construction.

positioning using an RTK-GPS device This requires computer models with the – PHYSICAL SYSTEM was vital, and hundreds of samples were right physical rules, which can compute collected during the seven measurement waves, tide and sediment transport based

campaigns conducted by Delft University on known relations. However, fine and THREE and Wageningen Marine Research. The coarse sand grains have not been treated 62 samples were later dried, pre-treated and separately in models to date. An in-depth 63 Figure 3. reconstruction was therefore made of the coarse sand grains are not fully lifted up just one example how this information can 455 (a) 455 (b) 455 (c) 455 (d) Overview of surveys development of the sandy bed of the Sand into the water column in quiet to moderate be applied in the design of future coastal of median grain size 454 454 454 454 Motor over the first 2 years, which agreed conditions (Figure 5), which means they interventions, by adjusting properties to (D50). well with the observed behavior. The model remain close to the bed. The fine grains, on minimize impact or even to obtain a desired 453 453 453 453 results are shown as the background color, the other hand, are easily lifted to the top change in habitat. while the measurements are shown as of the water column in all conditions. Areas 452 452 452 452 colored markers (Figure 4). Note that a clear with a tendency towards erosion therefore The implications of this study stretch Northing [km RD] T0 (2010 Oct) T1 (2011 May) T2 (2012 Aug) T3 (2013 Feb) coarsening is present at the Sand Motor lose more fine sand grains than coarser beyond sandy coastal maintenance 451 451 451 451 (in red) and fining along the adjacent coast grains (which stay closer to the bed). This measures, since port breakwaters will 71 72 73 74 75 71 72 73 74 75 71 72 73 74 75 71 72 73 74 75 Easting [km RD] Easting [km RD] Easting [km RD] Easting [km RD] (in blue). results in an armored top-layer with coarser presumably have very similar impacts on grains (shown as a red layer on top of the the sandy bed and marine habitat. In The model permits us to explore various bed of the central cross-section in Figure 6). addition, our study showed that fine and (e) (f) (g) 455 455 455 alternative situations, which provides The coarsest sediment also clearly coarse sand grains behave very differently insight into the functioning of the coastal accumulates in shallow water and finer in deeper water, which is seldom considered 454 454 454 system. For example, the model shows that sediment in deeper water. in studies of the seabed. Furthermore, D50 [ m] 453 453 453 a situation with only tide can have a similar evaluating long-term changes to the effect as the historic situation with both So, what does this mean for the natural coastline due to sea-level rise will require a 100 150 200 250 300 350 400 450 500 550 452 452 452 waves and tide. Decreasing the cross-shore habitats? In essence, the coarse grained good understanding of the transport rates Northing [km RD] T4 (2013 Oct) T5 (2014 Feb) T6 (2014 Sep) width of the Sand Motor also considerably area is a more difficult habitat for juvenile of the sand grains in deeper water, which 451 451 451 reduced the coarse sand patch in deeper flatfish (Page 119), as they will have more improves substantially when the numerical 71 72 73 74 75 71 72 73 74 75 71 72 73 74 75 water. More importantly, the modeling difficulty burying themselves in the sand, models calculate the behavior of fine and Easting [km RD] Easting [km RD] Easting [km RD] results can also help answer the underlying while the fine grained region at the adjacent coarse sand separately. questions. The model clearly shows that the coast provides a suitable habitat. This is

455 10 Figure 4. (right) 2 Bed level (Feb 2014) Comparison of modelled and observed grain sizes of the bed in 454 5 Initial bed (Aug 2011) February 2014 (i.e., 2.5 years after construction of the Sand Motor). 1 MSL

distance 0 453 (b) Substrate material Cross-shore (a) Figure 5. (below) 0 1 2 3 4 452 -5 Illustration of the suspension of coarse and fine sand grains into the 2 451 (c) -10 water column for quiet, intermediate and severe conditions. Northing [km RD] (a) Sand Motor peninsula 71 72 73 74 1 Easting [km RD] 10 distance

Fine sand 5 Coarse sand 0 1 2 3 4 0 2 Figure 6. D50 Representative -5 1 vertical cross- 400 -10 sections of the (b) Northern flank Cross-shore Cross-shore coast at the 350 0 1 2 3 4 central, northern 300 10 2 and southern part of the Sand 250 5 Motor, showing 1 0 the coarser 200 or finer bed -5 – PHYSICAL SYSTEM [km] [km] [km] [km] [km] [km] [km] distance distance Feb 2014 Oct 2013 Feb 2013 Aug 2012 Cross-shore 0 1 2 3 4 (respectively 150 Bed level Bed level Bed level MSL] [m MSL] [m MSL] [m Alongshore distance [km] in red or blue -10 Distance from the bed 100 (c) Southern flank

D [ m] THREE 50 colours). With landward side on 1000 1500 2000 2500 3000 3500 4000

64 quiet intermediate severe <130 130-160 160-190 190-220 220-250 250-280 280-310 310 340 340-370 >370 the right. Cross-shore location [m] 65 5 2 1 7 Figure 1. 3 Sebastian Huizer (right) hydrogeological cross section (along ´ black line, A–A’). The dashed line in the A A' cross section marks the bathymetry prior 0 THE IMPACT OF LARGE-SCALE NOURISHMENTS ON FRESH to the construction of the Sand Motor. The wave-shading pattern marks the erosion or athetr ror to ontrton GROUNDWATER RESOURCES accretion of sand between 3 August 2011 hreat Sand Motor Auer1a and 3 June 2016, -5 and tard (below) Contour map of topographic height Auer1 (in meters with respect to the NAP datum) Autard2 Sebastian Huizer will defend his PhD in 2019 Most coastal regions around the world rely the overall impact of the construction of of the Sand Motor on 3 August 2011, with the -10 at the Faculty of Physical Geography at on groundwater as their primary source the Sand Motor on fresh groundwater location of monitoring wells (black points) University of Utrecht. He joined Arcadis of freshwater. Excessive groundwater resources was likely limited. Effects would Height [m NAP] [m Height and pumping wells (red points). in 2018 as a geohydrologist. extraction, population growth, sea-level mainly take place during the last stages of er rise, and increases in storm surges threaten the construction and in areas close to the -15 (Tentative) dissertation title: the availability of freshwater in many, often shoreline with little fresh groundwater. ellsreens “Fresh groundwater in large-scale beach densely populated, coastal communities. nourishments - Growth of freshwater Coastal lowlands and small islands are The subsequent effect occurs during the droeoloase resources in coastal areas." particularly at risk, because they are most lifespan of the Sand Motor. The beach -20 susceptible to coastal flooding. To protect will expand seaward, thus displacing the 0 500 1000 1500 2000 PhD supervisors: vulnerable coastal areas, an optimal direct influence of the North Sea towards Distance in transect [m] Mark Bierkens (Utrecht University) management of the coast and coastal fresh the newly created shoreline. Combined Gualbert Oude Essink (Utrecht University) groundwater should be adopted. with the likely growth of adjacent dunes fine sand medium-coarse sand sandy clay (Chapter 4), the local extension of beaches clay/peat erosion/accretion (2011-2016) One way to protect groundwater is to and dunes will lead to an increased volume implement coastal protection measures, of fresh groundwater. This growth is driven with the aim to protect the coast against by precipitation, groundwater flow from erosion and flooding. As discussed in the dunes to the site, and a local shift in the Chapter 1, the Sand Motor is a prime impact of the sea. m example of this strategy and is one of the 0 500 1000 1500 ´ few adaptation approaches that might While the direct impact of the construction help to preserve or even increase the of the Sand Motor on fresh groundwater was available volume of fresh groundwater. predictable and limited, the indirect impact Since the Sand Motor is the first of its of its creation is more complex. This is a kind, little is known about the influence of result of the morphological evolution of the North Sea mega-scale beach nourishment on fresh Sand Motor (Page 53) and the exposure to groundwater resources. To date, nothing tides, waves, and storm surges (Figure 2, Sand Motor was known about the dynamic nature of next page). In other words, the potential 7 A' 2 1 ! this coastal system (Page 53). This raises change to fresh groundwater resources ! ! the question: what is the impact of the Sand is largely controlled by highly dynamic Motor on fresh groundwater resources? processes, which are hard to predict. To map !3 !8 the changes to fresh groundwater resources A The Sand Motor can affect fresh and to determine the impact of the various !5 groundwater resources in two ways: coastal processes in more detail, extensive !4 6 1. directly, during the construction of the field measurements and model simulations Salt ! mega-scale beach nourishment, and were conducted on the Sand Motor. ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! 2. subsequently, throughout its lifespan. Fresh Foredunes The Sand Motor was constructed by To better understand the impact of the Sand depositing, pumping and spraying a mixture Motor on fresh groundwater resources we – PHYSICAL SYSTEM ! Pumping wells << -10m-10 m -6-6 -- -4 00 - 2 66 -- 8 of sand and seawater taken from sand pits in asked three questions: ! the North Sea on the project site. Seawater 1. What is the potential increase in fresh Monitoring wells -10-10 - - -8-8 -4-4 -- -2 22 -- 44 88 -- 1010 accompanying the sand led to a salinization groundwater resources at the Sand Motor THREE Fresh-saltFresh-Salt interface interface -8-8 -- -6-6 -2-2 -- 00 44 - 6 >> 10m 10 m NAP NAP of the nourishment and its immediate over a long period? 66 Transect A-A' vicinity (the shore and beach). However, 2. How do tides, waves and storms influence 67 3 Figure 2. the fresh groundwater lens in the Sand in fresh groundwater resources in the model. This suggests that groundwater Illustration of coastal Motor? Sand Motor. models can be used to predict the 2 hydrodynamic 3. What were the actual changes in the effects of tides and storm surges on fresh processes at the 1 volume of fresh groundwater in the study The impact of tides, waves and storm surges groundwater resources. In addition, detailed measurement site. area since the Sand Motor’s construction, on fresh groundwater was successfully measurements and model simulations of 0 and which processes drove these monitored with a technique called “electrical tides and storms surges help us to improve changes? resistivity tomography.” This technique our understanding of the mechanisms -1 uses differences in the electrical resistivity that affect coastal fresh groundwater. This -2 To accurately assess the effects of the Sand (or conductivity) of, for instance, sand and might help water managers in the design Motor on fresh groundwater resources, the salt to produce two-dimensional images of monitoring systems or to assess coastal -3 groundwater system was comprehensively of the groundwater salinity in the subsoil groundwater availability. -4 analyzed (Figure 1). First, data was (Figure 4). Measurements were taken near Depth MSL] [m collected from local water authorities (e.g., the shoreline on the outer perimeter of 0 50 100 150 200 250 300 350 400 450 boreholes, pumping rates, historical maps, the Sand Motor. Over a period of several Profile distance [m] groundwater levels, groundwater salinity), months, we were able to observe changes and groundwater levels and salinities were in the thickness of the fresh groundwater monitored at the Sand Motor. This data was lens every 30 minutes, in both calm and 5 8 used to reconstruct the spatial distribution turbulent weather conditions.

Figure 3. ] of groundwater levels and salinities before -1 Simulation of 0 7 and after the construction of the Sand Most of the measured changes in yr historical coastal 3 Motor. This revealed interesting insights groundwater levels and salinity could be erosion (based on into the geological landscape evolution. imitated using a numerical groundwater -5 6 paleogeographic Furthermore, insight was gained on the model. This proved that with a thorough maps), sea-level pumping rates in the Solleveld dune area, understanding of the local system, rise (black line) -10 5 as shown in Figure 3. groundwater models can be used to make and groundwater accurate predictions of the impact of tides extraction (blue) -15 4 A numerical three-dimensional groundwater and storm surges on fresh groundwater in the period model was used to reproduce and predict resources. 1890–2010; dashed -20 3 the growth in fresh groundwater resources lines indicate in the study area. Model simulations Thus, mega-scale beach nourishments such Sea MSL] level [cm estimates, and predicting the morphological change of the as the Sand Motor can lead to a substantial vertical grey lines -25 2 Sand Motor up to 2050 confirmed that the increase in fresh groundwater resources. refer to stress Sand Motor could lead to an increase This suggests that local mega nourishments periods. -30 1 of fresh groundwater of between 0.3 and might be an effective solution for low-lying 3 Groundwater extraction [million m 0.5 million m per year. Reconstructions of coastal regions. In the Netherlands we -35 the growth of the freshwater lens between generally have enough fresh groundwater 1500 1600 1700 1740 1800 1890 1930 1970 2010 2011 and 2016 showed that this increase was for everyone. But many other countries Time [years], period 1500 – 2010 primarily caused by groundwater recharge, suffer from droughts or salinization, which highest land-surface inundations due to sometimes coincide with inundation of the storm surges, groundwater in- and outflow, coasts. Large-scale sand nourishments may ] Figure 4. 30 -1 and to a lesser extent by morphological become an interesting solution for some 3 3 3 30 3 14-11-2014 10:5 3 01-12-2014 14:57 3 11-12-2014 1:27 2-D images of 20 changes. areas, to protect the hinterland and preserve

2 2 2 the measured 2 2 2 -1 and increase fresh groundwater resources. 10 groundwater salinity However, the growth in fresh groundwater 1 1 1 for three instances 1 1 5 resources from 2011 to 2016 was smaller However, the growth of fresh groundwater in 2014: 00 00 00 than previously predicted, because of resources in a mega-scale beach 2 14 Nov. 11:00; coastal flooding and because the initial nourishment are highly dependent on the -1 -1 -1-1 1 Dec. 15:00 (after -1 -1 1 geomorphological changes had been shape and location of the nourishment, the

a calm weather -2-2 -2-2 -2-2 -55 underestimated. Naturally, the accuracy precipitation, the evaporation, the frequency – PHYSICAL SYSTEM period); and Height MSL] [m of long-term morphological predictions of and the intensity of waves and storm surges, -3 -3 -3-3 11 Dec. 19:30 -3 -3 -22 the Sand Motor will affect the reliability of and local hydrogeological conditions.

(after substantial -4 -4 -4-4 1 the fresh groundwater predictions. These At the Sand Motor, observed changes THREE -4 10 20 30 40 50 60 70 80 -4 10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80 -1 inundations). 10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80 combined discrepancies will lead to larger in groundwater levels and salinity could Groundwater salinity [g TDS L 68 Distance transect [m] Distance transect [m] Distance transect [m] errors when predicting the actual growth largely be simulated by the groundwater 69 Figure 1. Figure 2. (Page 72 Figure 3. (Page 72 Figure 4. (Page 72 Figure 5. (Page 72 Iris Pit The location of top left) top right) bottom left) bottom right) the Sand Motor A photo of the The sonic drill with Two cores sampled A photo of a sample and the sand pit, southwest part at obtained sediment along the water line taken at the Sand ENVIRONMENTAL IMPACTS OF AN INNOVATIVE BEACH with sampling the Sand Motor from the Sand at the lagoon (left) Motor placed under locations from GRID, including bog iron Motor presented and the lake (right) a microscope. NOURISHMENT BOREHOLE and ore fragments and by Bert Woertink of the Sand Motor SAND PIT. shell fragments. (from Woertink with material from the Waterpompen) and surface till a maximum observed by Iris Pit. of 50 cm depth. Iris Pit will defend her PhD at the The main question we studied was: Are wells 10 to 20 m deep at the Sand Motor, Copernicus Institute of Sustainable there any environmental risks involved when we decided to work together and hire a Development at Utrecht University in 2019, applying a mega beach nourishment? Sand sonic drill in order to collect sand samples, where she currently works as a lecturer. on a beach can form an environmental risk water samples, and finally create a hole because of the biogeochemical processes for the well. A lot of time was also spent in (Tentative) dissertation title: involved. For example, we expect that the lab: sieving, dissolving sand in strong “The Sand Engine: Ecological and the transfer of sea sediment from anoxic acid and diluting water samples because toxicological risks from geochemical conditions (with limited dissolved oxygen) of the high chloride concentration. When Sand processes." to oxic (atmospheric) conditions will lead possible and necessary, we measured the Motor The Netherlands to changes in biogeochemical processes: samples on different machines like a grain PhD supervisors: interactions with the atmosphere, freshwater size distributor or a scanning electron Stefan Dekker (Utrecht University) and sea sediment may affect mineralogical microscope. Jasper Griffioen (Utrecht University) composition, salinity, the availability of toxic Martin Wassen (Utrecht University) trace elements, and the buffering capacity The 21.5 million m3 of sand used to construct to maintain neutral pH conditions. As a the Sand Motor was obtained from the result, environmental conditions may vary sea bed 10 km offshore, from so-called on a mega beach nourishment, increasing sand pits, specific areas assigned by or decreasing the preferred environmental Rijkswaterstaat for sand mining. In general, GRID samples conditions for flora and fauna, but also sand is collected to a depth of 2 m from the BOREHOLE samples for humans. In general, sand is considered surface of the bed, enough for a “traditional” SAND PIT samples “clean” and therefore few studies have beach nourishment. A larger amount of sand pit investigated the chemical variation of sand, sand was needed for the Sand Motor, and especially at sand nourishments. Hence, we therefore sand was retrieved to a maximum Sand Motor explored the Sand Motor, compared it to depth of 6 m. The sand was transported to dunes different beach nourishments, and finally the shore with large ships and released via dredging sludge depot obtained an overview of possible risks the bottom of the ship or sprayed through that may or may not be present at a beach the air in a process called rainbowing nourishment. (Page 14).

To study beach nourishments, one has to The sand used for the Sand Motor originates do fieldwork, and a lot of it. However, to from two different geological layers: do this, we first had to explore the best a Holocene marine layer (up to twelve way of doing that fieldwork. Different carts thousand years old) overlies Pleistocene were used to transport equipment and the fluvial sand (between twelve thousand and samples we took from sand and water. The two million years old). Because the sand most productive (and relaxing) fieldwork comes from different time periods with a was when Deltares was able to use their varying sea level, the sand showed chemical 4x4 to drive on the beach. This saved us variations, with the Holocene sands

a lot of time and gave us shelter when the containing many more reactive minerals – PHYSICAL SYSTEM wind was blowing sand in our nose and compared to the Pleistocene sands. As a ears. Sampling surface sand was easy, but result, the Sand Motor contains a mixture

sampling groundwater at the top of the of Holocene and Pleistocene sand, which THREE Sand Motor was a different story. When is also visible when you walk on the beach: 70 a colleague wanted to bore groundwater some spots are very orange/yellow and 71 others show a greyish color. Furthermore, to that of seawater. If the pH decreased to to humans, it might make it unattractive for the Pleistocene layer had some surprises, acid conditions, toxic trace elements would soil organisms to create large populations. like bog iron ore (5-20 cm large orange/ be more likely to dissolve in the water, which Besides that, the Sand Motor has developed brown rocks) and layers of shells. The might cause a local problem for flora and relatively rapidly, creating such a dynamic amount of bog iron ore and shell material at fauna. environment that certain conditions like the surface of the Sand Motor has increased a tidal flat will not be present for long over time, as the fine sand is transported In general, contamination is mainly present and therefore cannot stabilize for nature more easiliy by the wind than the bog iron in the finer soil fractions, like clay, because development. ore and shells. of their high diversity in minerals and an overall negative charge. As a result, The most interesting mineral we studied, dredging companies make sure that not too and a very common one on the seabed, is much fine material is present in the sand

pyrite. Pyrite (FeS2), which is also known used for beach nourishment. In addition, as fool’s gold, forms on the seabed when coarse grain size distribution will not be oxygen is lacking. Besides iron (Fe) transported as easily by wind and water. and sulfur (S), pyrite is known to have Compared to Schiermonnikoog, which has a “contamination”: when pyrite is formed, toxic natural beach, the Sand Motor, as well as the trace elements are attracted, like arsenic, traditional nourishments at Julianadorp and cadmium and copper. When the Sand Motor at Zoutelande, have a much coarser grain was created, a large amount of the sand was size. In addition to grain size distribution, exposed to the atmosphere, and the oxygen we compared the chemical composition could make the pyrite in the sand unstable. of the Sand Motor, the two traditional As a result, pyrite can dissolve in water, nourishments, and the natural beach. where iron likes to precipitate again. Sulfur The most interesting difference is in the will stay in the water and the toxic trace unsaturated zone, the sand layer above sea elements can either be attracted to minerals level where rainwater infiltration and oxygen or stay mobile in the water. Arsenic turned can play a large role. The unsaturated zone out to be especially interesting, because it at the traditional nourishments is generally can have quite high concentrations locally less thick than at the Sand Motor, and in the pore water - water in the spaces almost non-existent at the natural beach. between the sand. Although local arsenic This means that the intensity of rainwater concentrations can be much higher than influence and oxidation is largest at the allowed in drinking water, the presence of Sand Motor, where the consequences of arsenic in pore water does not create a risk pyrite oxidation are most visible, and the for humans. To be sure, we collaborated with highest risk that toxic trace elements may be the Dutch National Institute for Public Health mobilized. In contrast, at both the traditional and the Environment (RIVM) to rule out any beach nourishments and the natural beach, human risk. the influence of seawater is almost 100% and the buffering capacity stays intact, even

Calcium carbonate (CaCO3) is a very though the CaCO3 in the sediment can vary. important mineral, as it buffers water when the pH is low because of chemical reactions. Another unique aspect of the Sand Motor For example, rain has a pH of around 5 is the time frame. Traditional nourishments

and CaCO3 will dissolve in water to make are periodically replenished with fresh sand it pH neutral again. Seawater on the other (every 2-5 years), whereas the Sand Motor hand, contains a high amount of dissolved can “develop” for 20-30 years. Because of

CaCO3 and therefore a pH of around 8.1. the design of the Sand Motor, the inner side With the Sand Motor reaching a maximum of the hook creates conditions where fine

height of 6 m above sea level, rainwater can materials, like clay particles and organic – PHYSICAL SYSTEM infiltrate the sand. Fortunately, the Sand material, can be deposited. This material

Motor contains a high amount of CaCO3, attracts soil organisms related to a tidal flat,

and during the life span of this mega beach as occurs at the Wadden Sea, but it can THREE

nourishment, enough CaCO3 can dissolve to also bring contamination. Even though the 72 maintain a pH that is neutral or comparable contamination is relatively low and harmless 73 Figures on this Timothy Price and next page: MEGAPEX2014 (Image courtesy: MEGA PERTURBATION EXPERIMENT 2014 (MEGAPEX2014) Top right: screenshot NPO2 Kennis van Nu; Bottom right: Esther Kokmeijer; SPECIAL Far right and below right: Marion Tissier; Below, left: Matthieu Timothy Price was a postdoctoral researcher at the Vrije Universiteit and South Africa). In addition to this, more than 10 BSc and MSc de Schipper; Amsterdam for the NatureCoast research program in 2013 and 2014. students participated as part of their thesis work. Far below, left and He currently is an assistant professor of Coastal Morphodynamics at right: Timothy Price; Utrecht University. Although each research group organized its own research, all Next page, left: participants could benefit from the centrally organized logistics Esther Kokmeijer; and infrastructure, such as housing, a small field station, transport Next page, right: In addition to the ongoing monitoring of the Sand Motor by on the beach and permits. In preparation for the campaign, all Marion Tissier.) Rijkswaterstaat (morphology, wave height, salt spray and sand NatureCoast and NEMO researchers met at the Netherlands Institute transport into the dunes), the NEMO project (bathymetry, for Sea Research (NIOZ) in Yerseke to present their plans for the sediment composition, offshore currents, turbidity) and the twelve campaign, to fine-tune measurement locations, and to brainstorm NatureCoast researchers (surf zone morphology, dune vegetation, on potentially overlapping research areas. fish and bird counts, groundwater levels, geochemistry), the NatureCoast and NEMO postdocs organized a large six-week field Overall, the campaign resulted in a unique, publically available data campaign in September and October 2014 through a joint initiative. set of multidisciplinary measurements covering fourty-eight days, including one big storm. More importantly, the teamwork and This campaign, called Mega Perturbation Experiment, or cross-disciplinary interactions during the six weeks in the MEGAPEX2014, aimed to perform multidisciplinary fieldwork field sparked new collaborations and broadened the scientific and to stimulate interdisciplinary collaboration in the process. In perspectives of the participants. Besides its scientific achievement, contrast to the more common monodisciplinary approach to field MEGAPEX2014 gave rise to significant outreach, including a data collection, this system-approach to coastal research fit the NatureCoast documentary, weblogs, excursions, radio interviews, NatureCoast philosophy. and an item on national television.

In total, MEGAPEX2014 involved more than 40 researchers from the NatureCoast consortium as well as other national and international organizations in the field of coastal research (from Sweden, UK, USA – PHYSICAL SYSTEM THREE

74 75 Figure 1. Gerben Ruessink Beach use Sand Motor in summer. COASTAL RESEARCH AND MANAGEMENT: WHAT IS NEXT?

REFLECTION

Gerben Ruessink is a professor of Wave-dominated Coastal estimates for sea-level rise mean that by 2100 nourishment volumes Morphodynamics at the Faculty of Geosciences at Utrecht University. would need to increase by a factor of 12 to 20. Does this mean we need more nourishments of the Sand Motor type? Is that the solution? The Sand Motor has been heralded as a boldly innovative solution to save our beaches from rising seas. Irrespective of whether one In my humble opinion, it is not, or, more precisely, not entirely. The agrees that the Sand Motor is the best solution, let alone the only current scenarios for sea-level rise demand for a truly innovative one, there is no denying that the 21.5 million m3 of sand nourishment change in coastal management policy, a drastic change in the meant a massive upscaling with respect to more traditional way we look at sediment management; we need to move away beach and shoreface nourishments, and that implementing it was from the basic notion that safety just demands a sufficiently a truly daring achievement. The Sand Motor also resulted in a large static volume of sand. Evaluation of these predominantly research effort worthy of its size, with a multidisciplinary approach shoreface nourishment projects teaches us that such nourishments unprecedented for the Dutch coastal community. This section can severely limit the dynamics of natural phenomena, such as provides a personal look back, and into the future. Should the Dutch sandbars. Another problem is that measures to increase the safety implement another Sand Motor, especially now that scenarios for of the most seaward dune have reduced it to an artificial sand dike rising sea-levels that were considered almost absurd a decade ago with suppressed dynamics and, unintentionally, a severely reduced are becoming thinkable? number of plant and animal species. In other words, measures in one coastal subsystem can have far-reaching, often negative The Sand Motor was constructed as a massive disturbance to a consequences elsewhere. wave-dominated sandy coast. Under natural conditions such a coast is fairly smooth in the alongshore direction. True, natural Let’s do better: we should not just talk about saving “our beaches,” sandy coasts also present alongshore variations, but the Sand Motor but about saving “our coasts.” There is an imminent need to was unprecedented in its size. This was purposely done to ensure re-connect different coastal sub-systems with each other, and to that nearby coastal stretches would be fed. Researchers argued truly stimulate large-scale natural dynamics rather than imposing that one could learn much more about coastal behavior from a measures that limit natural processes. In coastal policy, this must heavily disturbed site, such as the Sand Motor, than from a natural, mean a shift from evaluating whether the coast is safe to whether undisturbed coast. the coast is healthy: we need to ask whether it is sufficiently dynamic, whether it has sufficiently diverse habitats and, overall, While this idea makes perfect sense and the research that was whether it is truly climate resilient. Sand motors can surely play conducted resulted in stunning new insights, the Sand Motor a role in this new policy, but it is critical that, where possible, the also resulted in processes that would not generally occur along nourished sand benefits the entire coastal system, not just the a smoother wave-dominated coast. Examples include tidal- nearshore. Though this was not the case here, it should be in the current separation and eddy formation (Page 54), unprecedented future. We should do more with less sand. alongshore variability in sandbar dynamics and possible rip-current formation (Page 58), and sand-sorting processes seaward of the surf zone (Page 62). What made the research at the Sand Motor truly unique is that it included topics not commonly considered in coastal engineering projects, such as the effects of the nourished

sand on the local and regional hydrology (Page 66) and the – PHYSICAL SYSTEM “cleanness” of the sand (Page 70).

What is next? By 2018 it has become clear that sea-level rise along THREE the Dutch coast could be more extreme than was considered 76 realistic during the design of the Sand Motor. Current high-end 77 OCTOBER 2012 Physical geography, senior coastal specialist JAN MULDER – RIJKSWATERSTAAT

INTERVIEW

In what way is the Sand Motor unique to you? What are the main findings of the "The Sand Motor – as a large scale NatureCoast program for you as end-user? contribution to coastal maintenance – "Perhaps the most striking (although is unique because it was the first time not necessarily most important) that something like this was carried out, immediately comes to my mind concerns anywhere. And also because I do not think dune development. It was thought that the the Sand Motor, in the shape and the way Sand Motor would contribute to dune growth is has been designed and implemented, in the entire dune area, from dune front up will ever be applied again. The Sand Motor into the old dune area behind. Looking at the was specifically designed for this location, research results, this does not seem to be with the aims that were in play at the time. the case yet. Up to now, dune development A Sand Motor-like solution will always be appears to have been stimulated mainly tailored to the specific local situation, and it at the dune front, resulting in wider, not in will always look different." higher dunes. We had not expected that, and at this moment it is hard to attach a value How do you see the role of scientific judgment to it. However, it seems clear that research at the Sand Motor, as end-user? for the long run it is an important issue." "As an end-user, this is very important because of its unique character. And not only How does the rest of the world view the because it was the first time this was done, Sand Motor in your experience? but also because the project besides just a "The Sand Motor was widely profiled in the technical design, also implied consciously media as a unique event and phenomenon; consideration of the social context. Scientific regularly spoken of in terms of "the Dutch research helps to understand and explain show what they can do here." That pride, why the Sand Motor works, not only that sentiment of Dutch glory, I felt that a technically but also socially. This can yield bit too. Yet I only partly agree with it: you lessons that may help to improve the design are of course Dutch yourself and feel a of a next Sand Motor-like solution." certain pride when people say it. However, at conferences I have specifically asked How relevant is multidisciplinary research foreign colleagues about it, and they on the Sand Motor? confirm: "This is typical Dutch…" But they "Very important, because for me, the Sand add: "…. something like that can only be Motor is not a purely technical solution, done in the Netherlands." The latter is very but rather a multidisciplinary approach important and refers to the fact that the aimed to meet various societal objectives. Sand Motor is more than a purely technical A solution primarily addressing flood solution, but above all a solution that is protection in the Dutch context, but at the embedded in Dutch society. The statement same time, meeting with the demand for indicates that the Sand Motor as it is, may

more natural areas in the densely populated only be of limited value to the rest of the – PHYSICAL SYSTEM part of the Netherlands, and stimulating world. The specific context of the Netherlands recreation opportunities. In short, it is a made this Sand Motor possible. The main value

multidisciplinary project, and if you want to the rest of the world may be to consider a THREE to learn from it, you will have to study it in comparable long term and multidisciplinary 78 a multidisciplinary way." approach that has been the basis of it." 79 MARCH 2013 Coordinator Beach Safety MICHEL PUGLIA – LIFEGUARD & RESCUE TEAM, THE HAGUE

INTERVIEW

What makes the Sand Motor unique for you your work from a scientific point of view, question: Is the Sand Motor on track and as end-user? because you look at all kinds of research does it do what it needs to do? If that is not "It is unique that the beach of the Sand results that are published. As a result, for the case, then we have to adjust all kinds Motor is gradually becoming wider, and example, we are also thinking about the of risk assessments. But at the moment the of course I look at the beach safety ecological perspective now, the natural researchers indicate that the developments perspective. We have to constantly monitor aspects that are also part of the beach." are going according to plan. This is very nice the safety, and that has two aspects: the to hear from a scientific research program, perceived safety and the actual safety. "For us the research has been an because it corresponds to what we have On the one hand, the Sand Motor has enrichment: it has generated new noticed in the field." considerably helped to improve safety, but knowledge and broadened our insights on the other hand we can never say that it is and experiences beyond our day-to-day Which aspects of the Sand Motor system 100% safe. That sense of security is a bit of practice. Being part of such a scientific are important for swimming safety, and has an equilibrium, something we have to keep program has brought us into contact with scientific research made it sufficiently clear in balance." researchers and shown us how they expand for you to be able to give advice on this? our knowledge. The program has also "The most important aspects for us are "For example, the groins, here officially expanded our network; we can now find water, currents, tides, topography, wind, called the Delflandse Hoofden (Delfland experts much more easily." wind erosion. The researchers have Heads), play a big part in safety. People measured this extensively and converted often get into trouble because of the rip How relevant is multidisciplinary research the data into maps. The outcomes are currents along those groins. Because of on the Sand Motor for you as end-user? certainly understandable, but can always the Sand Motor, these groins have been "Multidisciplinary research is important. be improved. Of course, the more detailed gradually covered and as a result people feel Of course, some things are just nice to the maps are, the better for us. But the safer. But that does not mean that there is know, interesting, whereas other things are explanation also matters a lot. If a researcher no danger anymore. " crucial for us as end-users. The knowledge comes to us with a map and explains the provided by the ecological research on the findings and what has been put into the "The width of the beach also gives a feeling Sand Motor is very interesting for us. It has map, that really helps us a lot. This also of safety. The beach can accommodate made us aware of the fact that we should allows us to start a discussion with each many more people, and it also provides not drive our vehicles through the young other. Lifeguards are often very hands-on, more different recreational opportunities dunes, for example. But our main interest and they prefer to talk to someone rather than before. The wider beach gives visitors a is knowing on how the sea moves, how than reading about the research.” sense of security, but with so many activities a sandbox like the Sand Motor develops. and people we also need a lot more Normally, we know a stretch of beach, we volunteers to monitor all of that. You can’t understand how it works, and we monitor it. take safety for granted, even if it is such a But now we are facing new developments all wide beach." the time, and the research program actually keeps us alert and up to date." How do you see the role of scientific research at the Sand Motor, as end-user? What are the main findings of the

"Very interesting, because we are normally NatureCoast program for you as end-user? – PHYSICAL SYSTEM only concerned with beach surveillance and "We conducted a risk inventory in relation making sure the beach visitors are safe. But to beach safety before the program to find

the NatureCoast program has shown us out what we could expect, and what we THREE many aspects that we knew were there, but should anticipate. So the most important 80 were not part of our daily job. You also see thing, especially for beach safety, is the 81 FOUR | DUNE DEVELOPMENT – DUNE DEVELOPMENT FOUR

82 83 Figure 1. Arjen Luijendijk Dune Formation (Image by JAM Visual Thinking) THE JOURNEY OF A SAND GRAIN FROM BEACH TO DUNES

INTRODUCTIONNTRODUCTION

In the Netherlands, dunes form our most important natural line of Bas Hoonhout introduces a newly developed numerical model that defence against rising sea levels and severe storms. As discussed is able to reproduce the observed aeolian transports and changes at in Chapter 3, the Sand Motor is an unprecedented large sandy the dry beach (Page 100). We will explain why the intertidal area is nourishment with 128 hectares of new land. Sand is always on the much more important for dune development than the width of the move, and such a wide sandy beach provides large potential for Sand Motor. We will also demonstrate how important the sediment wind-blown sand and hence dune formation. This wind transport composition is for the long-term development of the Sand Motor (also known as aeolian transport) causes the foredunes to grow and its dunes. and makes them dynamic, but it may also cause early dune development, which has so far been largely ignored in coastal In the final section, principle investigator Kathelijne Wijnberg reflects research. on this chapter’s findings and the implications for present and future coastal management (Page 104). In this chapter, we will introduce you to the interaction between aeolian transport, embryo dune formation, and dune vegetation as well as innovative monitoring and modeling techniques. We will follow a grain of sand as it travels from the wet beach to the dune. First, we need to know how dunes and vegetation have actually grown at the Sand Motor after its construction. We will show that the spreading caused by the natural forces of tides, waves and wind resulted in a fascinating formation of embryo dunes and vegetation (Page 86).

Next, we will discuss remote sensing monitoring techniques that help to identify key wind events at the Sand Motor. Isaac Wiliams (Page 88) explains how remote sensing techniques can efficiently reveal the conditions that are favorable for wind-driven transport (or that discourage it). Observations of large-scale transport events provide great insight into the meteorological, tidal and surface conditions that stimulate dune formation.

Early dunes can develop anywhere on the beach under specific conditions depending on the interaction of physical processes and weather. We will explain how and why embryo dunes develop, and how they can ultimately strengthen the foredunes. Marinka van Puijenbroek illustrates how important the height of the Sand Motor is for protecting the dune-building species against storms (Page 92).

Moving towards the main dune area, we will pay attention to the interaction between how vegetation takes hold and is covered by sand, which is essential for sustainable dune development. Corjan Nolet introduces the greatest dune-building champion – DUNE DEVELOPMENT and explains how important it is for protecting us against the sea

(Page 96). We will show you the added value of applying advanced FOUR drone techniques to measure the dune dynamics (burial rates) and 84 vegetation dynamics. 85 Arjen Luijendijk OBSERVED DUNE DEVELOPMENT

This section looks at the development of the construction of the Sand Motor but not However, our measurements indicate that dunes and vegetation at the Sand Motor in as quickly in the monitoring area as before the aeolian deposits in the dune lake and its first seven years after completion, but its construction. lagoon are of the same order of magnitude, first we will start with some recent history. giving a total average sediment deposition Dune development after the Sand Motor of 27 m3/m/yr in the Sand Motor domain, The Delfland dunes The new dunes are primarily located on which is on average 56% higher than along Early this century, the Delfland coast was the eastern edge of the Sand Motor near the adjacent coasts. designated as one of the “Weak Links” in the foot of the previously built coastal the coastal defenses—not because the reinforcement. A few small primary dunes Impact of wind-blown sand on Solleveld dunes had gotten weaker but because it have also developed on the southwestern The construction of the Sand Motor resulted was clear that storms could become more side of the Sand Motor. The new dune forms in a bare sandflat seaward of the existing severe in the future. Therefore, the Delfland are highly dynamic and therefore extremely Solleveld dune area. Prior to construction, sea defense was upgraded by placing a appealing in landscape terms. concerns were raised about the possible large volume of sand at the beach and negative effect this might have on the dunes. The operation, involving 17.6 million The area of new dunes is increasing slightly. ecological values of the Solleveld. After m3 of sand, was completed in 2011 with the Just less than one hectare formed in the construction, the amount of sand blowing Delfland Coastal Reinforcement. monitoring area in the first five years, which into the outer Solleveld dunes would appear is surprisingly much smaller than predicted to have increased slightly. However, in The beach and the dunes are important (23-27 hectares after 20 years). This can be absolute terms, the amount of sand being for nature and leisure activities along the partly explained by the fact that the dune blown to Solleveld remains limited. entire Delfland coast, which includes lake and the lagoon capture large amounts various strictly protected Natura 2000 of drifting sand and delay dune growth. The Vegetation and birds areas. This means that the dune area dunes are expected to continue to grow and The vegetation found on the Sand Motor landward of the Sand Motor, called this process should accelerate in the future, consists of characteristic sand couch and Solleveld, is protected from interventions particularly once the lagoon and the dune marram. These habitats are subject to in the area. Solleveld consists mostly of lake have filled with sand. international protection under international “old” dunes which were deposited by agreements. Sea holly, a red-list variety, is the sea starting in 3000 B.C. Another reason for the limited growth of growing in some locations. the dunes is the intensive shared use of the There is a relatively narrow strip of beach. The formation of a new row of dunes Between 2011 and 2015, almost forty species young dunes at the seaward part of in front of the old one is slowed by traffic on of birds were observed regularly on and Solleveld. This hilly zone is a few hundred the Sand Motor, particularly vehicles driven around the Sand Motor. The black-headed meters wide and has been affected by by supervisors, surveyors, and researchers. gull is by far the most common species the coastal reinforcement operations in The cleaning of the beach performed by the (Page 200). Other species that have been recent decades: a double foredune dating city authority of The Hague also prevents regularly seen are the common gull, herring from the late 1980s (the result of a dune dune formation. gull, grebe and great cormorant. strengthening operation) and a row of dunes approximately 60 meters wide as a result Lidar measurements show that the average from the Delfland Coastal Reinforcement. dune growth of 14 m3 per meter longshore per year in the Sand Motor domain is slightly – DUNE DEVELOPMENT For decades the Delfland dunes have lower than the dune growth rates along the

been growing steadily, both in height and adjacent beach stretches, while this stretch FOUR width, mainly due to coastline maintenance has a much wider beach compared to the 86 activities. This process has continued since other stretches. 87 20 Figure 1. (right) Isaac Williams Image from camera overlooking the lagoon area of the OBSERVATIONS OF AEOLIAN TRANSPORT Sand Motor in which 15 streamers can be observed within the intertidal area. Expanded area in 10 the lower half of the

image. White line Counts Isaac Williams has worked as a PhD Dunes play an important role in protecting low cost. In this case, images taken by the illustrates direction in candidate at the Department of Water low-lying areas against coastal flooding. Argus video tower iso camera station at the which the streamers Engineering and Management, University of Their growth, and their recovery after storm Sand Motor were used to identify wind- 5 propagate, which Twente since 2015. erosion, requires the supply of sediment driven transport events. The Argus video corresponds to the from the beach, which is driven by the wind. station has been collecting images every 30 mean wind direction (Tentative) dissertation title: To be able to accurately assess the dune minutes since 2013, across multiple cameras. at the time the image "The effect of mega-nourishment projects and its ability to protect against flooding, At the same time, a meteorological station, was taken. 0 on sediment supply to the dunes " this supply needs to be understood and mounted on the Argus tower at a height of 240 255 270 285 300 315 measured, both monthly and annually. 44 m, has been collecting data. This allows PhD supervisors: At these larger timescales, the supply of images to be related to the prevailing wind Streamer direction (°N) Kathelijne Wijnberg (University of Twente) sediment to the dunes is dominated by a conditions at the time they were taken. Suzanne Hulscher (University of Twente) few large-scale transport events. Large-scale transport events at the Sand Figure 2. (bottom) To identify when large-scale wind-driven Motor are often characterized by large, Image examined for transport events occur, we need to know elongated regions with intense transport streamers using the more than wind speed alone. In the ideal activity. Known as streamers, they rapidly developed method. situation, sediment is transported by the snake across the surface of the beach, Dots denote the wind once the wind exceeds a given critical moving downwind. Streamers are frequently center of areas of the speed. However, this threshold is affected observed in areas where the underlying image which were by other weather and surface conditions, beach is moist. These areas offer strong examined. The arrows which reduce the wind’s effectiveness in contrast differences with the streamers, point in the direction transporting sediment. The overall effect of which are comprised of drier, and thus of the identified these conditions on the transport system is lighter, sediment. The presence of streamers streamers. still not understood, which makes it difficult at the Sand Motor is illustrated in Figure 1, to predict when transport events will occur. which shows an image taken by a camera Figure 3. (top right) Since transport formulations are unable facing northeast overlooking the lagoon Real-world orientation to account for these additional factors, area. During the largest transport events, of the streamers estimates of sediment supply are both larger streamers are observed across the entire as determined than observed values and inconsistent. surface of the site. Identifying images in from Figure 2. The which streamers are observed allows us orientation is given In order to understand what conditions to identify individual large-scale transport about north (compass encourage wind-driven transport, we need events. To date, this has typically been done direction). Lines to link observations of large-scale transport manually, making the generation of long- correspond to the events to meteorological, tidal and surface term datasets a slow, tedious process. An mean wind direction conditions. It is challenging to make in-situ automated method has now been developed at the time of the measurements for this purpose that provide which identifies images containing image (dashed) and sufficient coverage in space and time. streamers, allowing us to document large- the average direction Remote sensing techniques offer a number scale aeolian transport events. of the streamers of advantages. For example, a camera that (solid). observes a beach can document surface This new method searches for streamers – DUNE DEVELOPMENT conditions over a wide area during daylight around a series of points within a given

hours for however long the camera system image. To do this, pixels are extracted FOUR is operational. This makes it possible to around each point and processed to form 88 generate long-term datasets at a relatively an aerial view of the surrounding area. 89 Figure 4. Figure 5. When streamers are observed from this wind speed is greater than 10 m/s. In spite Finally, we wanted to quantify how the Rose diagram illustrating the image averaged direction of streamers Rose diagram illustrating the directional distribution of measured perspective, they typically appear as of this, they were only observed in ~60 % of observed transport events correspond to and corresponding wind speed, for all images in which streamers wind speeds greater than 10 m/s for all images considered over relatively linear features. Consequently, each the images where the measured wind speed sediment supply. In this regard, the shape were detected by the developed method. Streamers are predominately 3 month period. area is examined for linear image features, was greater than 10 m/s. Figure 5 illustrates of the Sand Motor has some interesting observed from SSW, at wind speeds in excess of 10 m/s. which are then used to infer the presence the direction of winds that exceeded this consequences. The lake and the lagoon of streamers. Figure 2 illustrates an image threshold across all image frames and act as barriers for streamers. When the in which this method has been applied to Figure 4 shows the average direction of the streamers meet these areas, the sediment detect streamers. The arrows, each of which streamers for all images in which streamers that they carry is deposited. Regular represents 50 m, illustrate the orientation were identified. These figures illustrate that measurements of the surface elevation of the streamers around certain points in streamers occur over a narrower range across the site allow the change in volume the image. The corresponding real world of directions than the wind, and generally of these areas to be evaluated. The high orientations are shown in Figure 3. As can come from SSW. elevation of the Sand Motor has ensured be seen, the direction of streamers typically that, to date, the lake area has been isolated clusters around a mean value that is close to This method will allow us to examine the from marine processes. Consequently, that of the mean wind direction at the time entire image dataset from the Sand Motor, changes in its volume can be assumed to be the image was taken. identifying large-scale transport events almost entirely due to wind-driven transport over multiple years. The derived dataset can processes. Figure 6 shows the elevation of The method was used to identify images then be compared to meteorological, tidal, the surface of the site in August 2011, and showing large-scale transport events using a and surface conditions, which will provide Figure 7 shows how it has changed over test dataset consisting of over 1800 images further insight into which conditions are time. Consistent with the observations from from a single camera, which represents favorable (or unfavorable) for wind-driven the images, the lake has predominantly been three months’ worth of images. The images transport. In addition, this approach allows infilling from the SSW. Figure 8 highlights were also manually examined for streamers. us to investigate how the surface of the site that, after a relatively rapid initial period, The new method compares favorably with influences the direction in which streamers the infill of the lake area has stabilized to a the manual results, and is able to process travel. This has important implications for relatively linear rate of ~ 14,000 m3/yr. The the images in a fraction of the time. the amount of sediment transported to the trapping of sediment by the lagoon and lake Figure 7. Streamers were only observed in ~10 % of dunes. ultimately reduces the amount of sediment The change in elevation within the lake between August 2011 and the images, typically when the measured transported to the dunes. Figure 6. June 2015. There has been significant infilling as a consequence of The surface elevation across the lake area in August 2011 measured wind-driven transport, particularly in the SW. Lines correspond to the relative to the mean sea level. The dashed line corresponds to the spatial position of the + 1.5 m contour above sea level measured in +1.5 m contour which approximates the water level within the lake. 2011 (dashed) and 2015 (solid) highlighting the infilling.

z (m) z (m) 1e5 800 6 800 6 1.2 Figure 8. The cumulative 1.0

] volume change 3 across the lake 600 3 600 3 area through time 0.8 between August 2011 and June 2015. 0.6 Dots represent the 400 0 400 0 calculated volume y (m)

y (m) changes. Lines 0.4 denote error bands about the calculated 200 -3 200 -3 0.2 volumes. Cumulative Accretion [m – DUNE DEVELOPMENT 0.0

0 -6 0 -6 FOUR 0 200 400 600 800 0 200 400 600 800 12-02 12-08 13-02 13-08 14-02 14-08 15-02 90 x (m) x (m) Date [YY/MM] 91 Figure 1. a b Marinka van Puijenbroek The two main dune- building grasses in the Netherlands. EMBRYO DUNE DEVELOPMENT Figure 1a. Marram grass, Ammophila arenaria. Figure 1b. Sand coach, Elytrigia juncea.

Marinka van Puijenbroek obtained her PhD at The development of new dunes begins which could affect the establishment of the Plant Ecology and Nature Conservation with the establishment of vegetation on plants. The high elevation also means group at Wageningen University in 2017. She the beach. The vegetation traps the sand, that a large part of the Sand Motor is safe currently works as a researcher on dunes preventing it from blowing away, which from storms, as waves cannot reach these and saltmarsh vegetation at Wageningen results in a small embryo dune. Plant species areas. While this could be positive for dune Marine Research. that build dunes are specialized in catching development, note that the groundwater the wind-blown sand and can grow with level is quite low (2 m below surface) at Dissertation title: the trapped sand. In the Netherlands, there high areas of the Sand Motor, and this could "Dunes, above and beyond: The interaction are two main dune-building grass species, lower soil moisture content, which could between ecological and geomorphological marram grass (Ammophila arenaria) and slow down the establishment of vegetation Figure 2a. processes during early dune development." sand couch grass (Elytrigia juncea) (Figure 1). (Figure 2). 2015 Overview of the Over time, when the vegetation grows and Sand Motor. The 15 PhD supervisors: catches more sand, the embryo dune will Dune-building species established presence of dune- Frank Berendse (Wageningen University) transform into an established foredune. The spontaneously on the Sand Motor between building species Juul Limpens (Wageningen University) process of a bare beach developing into 2011 and 2015. The most plants established on the Sand Motor a foredune depends on the establishment in the southern part of the Sand Motor and and the location of of plants, the growth of the dune, and the around the lake, where quite large dunes the five transect in dunes surviving storms. have formed. We monitored the presence of 8 which we monitored the different dune-building species in five the vegetation more The establishment of plant species on the transects (Figure 2a). In 2015, dune-building extensively. beach depends on various environmental species covered a total area of 1307 m2 in factors. The beach can be a harsh all the transects: 76% of these dunes were Elevation NAP) (m environment with high soil salinity, low soil covered by marram grass and 24% by sand -1 moisture, salt spray, sand burial and erosion. couch grass. The high presence of marram Soil salinity and salt spray are higher closer grass corresponds to the low soil salinity on to the sea, whereas sand burial is higher the Sand Motor, since marram grass cannot Figure 2b. 2016 close to the dunes. These abiotic factors do, tolerate high soil salinity. Aerial photograph however, depend on the beach morphology: of the Sand Motor, on higher and steeper beaches, the soil We expected that dune-building species the points indicate salinity, salt spray, and soil moisture would establish more on the lower parts the plots in our field will be lower than on lower and gradual on the Sand Motor, because of the low soil experiment, the beaches. The Sand Motor has a distinctive moisture at the higher elevations. Although number indicate the morphology, since the beach is very wide the soil moisture was indeed quite low, the locations number. (800 m) and several meters above sea level dune-building species mainly occurred on (4–6 m above mean sea level). the higher elevations rather than the lower ones (Figure 3, next page). Furthermore, From studies of natural beaches, we know we did not find any correlation between that more embryo dunes can develop the presence of dune-building species on wider beaches. Large embryo dune and groundwater depth. From this we complexes can develop on beaches wider can conclude that the low soil moisture – DUNE DEVELOPMENT than 300 m; this indicates the high potential on the Sand Motor does not limit embryo

for embryo dune development on the Sand dune development; it is very likely that the FOUR 0 0,25 0.5 1 Kilometers Motor. The high elevation of the Sand Motor dune-building species are dependent on 92 could, however, affect abiotic conditions, precipitation for their plant growth. 93

Figure 3. (top left) Figure 4. (top right) Figure 5. (bottom) The distribution of the dune building grasses locations from sea to dune. The locations Frequency distribution of the elevation (m Growth expressed as the number of plants per Images of vegetation growth over 2.5 years. does not seem affected by the elevation; were selected to represent the entire Sand above sea level) for both the whole of the plot of dune building grasses Marram grass A photograph of one of our field experiment the absence of vegetation on some parts Motor (Figure 2b). We established four plots monitored transects and for points were (left) and Sand couch grass (right) planted at locations in 2014 four months after planting, of the Sand Motor could be because the of 50 x 50 cm at each of these locations, natural vegetation actually established on different distances (locations) from the sea on and a photograph 2.5 years later. This shows dune-building grasses cannot reach these and planted 20 plants of either marram the Sand Motor. Vegetation mainly occurred a natural coast (Texel) and on the engineered how fast embryo dunes can develop on the areas. The dune-building species on the grass or sand couch grass in each. Over at higher elevations at the Sand Motor. coast at the Sand Motor. Location I is closest Sand Motor. Sand Motor mainly occurred close to time, we measured the number of plants to the sea and location IV furthest from the sea. the foredune, where these species were at each plot. The same experiment was Although plant growth was initially lower on already present. In fact, there is hardly any conducted at a natural coast at the Hors, the Sand Motor, the high survival of vegetation vegetation on the seaward ridge of the Sand Texel to compare plant growth. during winter by the absence of storms Motor, which is much further away from any resulted in an overall higher plant growth. vegetation. Dune building species mainly In the first summer, the growth of planted disperse via rhizomes (root parts) and dune-building grasses was initially lower on seeds. Rhizomes are mainly dispersed after the Sand Motor than on the natural coast of Area a large storm, when the rhizome is broken Texel (Figure 4), probably due to the lower Sand Motor transects Marram grass Sand couch grass off from the maternal plant. The rhizome soil moisture on the beach. This would make Vegetation points can then establish on the location where it the dune-building grasses more dependent washes up, thus initiating the development on the precipitation here than on a natural Texel of a new dune. Storms can therefore have coast. In winter, average plant mortality a positive effect on the spread of dune- was lower on the Sand Motor than on the building species. natural coast, eventually resulting in higher vegetation growth on the Sand Motor. This High waters as a result of storms do not clearly indicates the positive effect of the Sand Motor Sand reach most parts of the Sand Motor, which high elevation, where there is no storm means that plant material of dune-building erosion, the most limiting factor for dune species cannot be deposited there. This development. The only field experiment

Frequency distribution could explain the absence of vegetation locations which showed substantial plant on higher elevations like the most seaward mortality were those closest to the sea .

Number of Plants ridge. The seeds of marram grass and sand Here, vegetation disappeared due to the couch grass are relatively small, and it is structural erosion of the Sand Motor by the Elevation (m NAP) unlikely that they could reach the whole sea. Due to the rapid growth of the dune- of the Sand Motor by wind dispersal. In building species in our field experiment, the addition, the seeds might be trapped by planted dune-building species created quite the lake in the middle of the Sand Motor, impressive dunes at the Sand Motor within 2014 2017 which might reduce the availability of seeds. three and a half years (Figure 5). However, these seeds could drift to the edge of the lake and find suitable conditions Overall, the Sand Motor has a huge potential due to the higher soil moisture there. This for dune development. The wide beach could explain the abundance of dunes in of the Sand Motor gives a lot of space for the area around the lake. The seaward ridge embryo dune development, and its high has been eroding since 2014, which could elevation protect dune-building species have a negative effect on the germination of against storms. This potential is already seeds; seeds might be blown away from the visible at the Sand Motor, where new seaward ridge, or seedlings might be unable embryo dunes develop and become bigger to survive due to sand erosion. every year.

Since the distribution of the dune-building grasses could be due to dispersal, we conducted a field transplant experiment, thus excluding the effect of dispersal and – DUNE DEVELOPMENT allowing us to compare the Sand Motor

with a natural coast. For the field transplant FOUR experiment, we planted marram grass and 94 sand couch grass in five transects at four 95 Figure 1. Small developing dune Corjan Nolet covered with beach grass (burial) sand Overview of how Trapping of transport plant-sand feedback wind-blown sand dynamics drives by beach grass CONTRIBUTION OF VEGETATION TO DUNE DEVELOPMENT coastal dune development.

Dune building feedback dynamics Corjan Nolet is a PhD candidate at the Soil Marram beach grass (Ammophila arenaria) dune development on the Sand Motor in Physics and Land Management group of is perhaps the greatest coastal engineer 2017. The dune cover density by marram Denser and taller Wageningen University. He has extensively that nobody has heard about. This rather grass has been mapped by satellite imagery. beach grass studied wind-driven coastal processes, using unremarkable looking grass is a dune- Together with the aerial photos, it is clear traps more sand remote sensing techniques and geospatial building champion: without it growing along that the foredunes form an uninterrupted More vigorous growth analysis. our shorelines, we would simply not have and densely covered dune ridge, while of beach grass such tall and broad coastal dunes to protect more sparsely covered embryo dunes have due to sand trapping (Tentative) dissertation title: us against the sea. Especially for a country formed at the foot of the foredunes, as well Spreading of beach "How biogeomorphic feedback drives dune below mean sea level like the Netherlands, as around the dune lake and on the southern grass to new places development along nourished coastlines." marram grass provides a very important part of the Sand Motor. contribution to coastal safety. PhD supervisors: To start to understand how this Coen Ritsema (Wageningen University) What makes marram grass such an effective development takes place, we compared the Michel Riksen (Wageningen University) dune builder (Figure 1), is that it not only morphological changes of the Sand Motor traps high amounts of wind-blown sand against the changes in dune cover density. in its leaves and roots, but that it will in Using yearly digital elevation maps, Figure 3 fact grow much more vigorously because shows how the average height of the Sand Figure 2. of it. Sand is basically like a fertilizer for Motor changed between 2013 and 2017, and Dune cover (%) The state of dune marram grass, causing it to grow taller and also how the dune cover density of marram development on denser. This reinforcing interaction (positive grass differed in September 2017 compared 10-35 and along the feedback) is the driving force behind to September 2016. The morphological map 35-65 Sand Motor in the coastal dune development: trapping sand highlights the dynamic nature of the Sand 65-90 summer of 2017. encourages marram grass to grow, which in Motor, showing how the sand has been 90-100 (Data derived from turn enhances the capacity of marram grass redistributed along the coastline through satellite imagery, to trap sand. To understand and predict wind and wave forces. The dune cover photos courtesy of dune development on and along the Sand map highlights the overall positive effect of Rijkswaterstaat and Motor, it is therefore essential to focus on the Sand Motor on dune development, as Jurriaan Brobbel.) how much sand marram grass can trap and the existing dunes have expanded or new how its growth is affected by it (Figure 1). embryo dunes have formed in most places.

Almost directly after construction, the Nevertheless, it must be noted that the conditions on the Sand Motor became quite dunes appear to have retreated slightly favorable for dune development: there is a in some places. Increased pressure by constant supply of fresh wind-blown sand recreational activities may have played a role towards the most seaward facing dune in this retreat. For example, the placement ridge (the foredunes), and the wide beach of beach cabins along the foredunes in provides a lot of space and acts as an 2016 may have hindered dune development effective buffer against erosion by storms. on the northern part of the Sand Motor. So far, this has ensured that the existing At the same time, mechanical cleaning of dunes along the Sand Motor are actively the beach during the summer may have – DUNE DEVELOPMENT growing and that small dunes (embryo negatively impacted newly developing

dunes) are developing on the beach around embryo dunes. This illustrates how the fact FOUR clumps of newly established vegetation. that the Sand Motor has to fulfil different 96 Figure 2 gives an overview of the state of functions (coastal safety, recreation and 97 Figure 3. (right) 1.5 Sand Motor morphology 2013 - 2017 Change in height (m/y) leisure, ecology, drinking water supply) can we identified changes in dune height Mapping changes -0.75 to -0.25 sometimes make striking a good balance and changes in marram grass greenness. in Sand Motor -0.25 to 0 challenging. Plotting the data (Figure 5) revealed an 1.0 no change / new coast morphology and 0 to 0,25 interesting pattern, which points towards dune cover density 0.25 to 0,5 Comparing the maps in Figure 3 made feedback dynamics in dune building. In of marram grass. 0.5 one thing clear: almost all the dunes on particular, the graph clearly shows that the Sand Motor, both the foredunes and marram grass grows better when it traps embryo dunes, only developed in areas more sand, albeit up to an optimal amount Corss shore (km) 0.0 where considerable amounts of sand were of sand per growing season. When too much deposited by wind. Although no clear sand is transported towards the dunes, the 0 1 2 3 4 5 6 relationship could be observed using the graph suggests that marram grass may get satellite data, this provided a first indication overwhelmed by sand, impeding its growth. that reinforcing plant-sand feedbacks drives At the same time, when marram grass 1.5 Dune cover Marram grass 2016 - 2017 Change in cover (%) the development of coastal dunes. To truly traps less sand than the optimal amount, <0 measure this feedback, we had to study it may not grow as vigorously as it could no change 0 to 33 the dunes in much more detail. One way potentially, meaning it also would not trap as 1.0 33 to 65 we did this was by aerial mapping with an much sand as it potentially could. octocoptor drone equipped with a high- 0.5 resolution camera that, once in the air, would This pattern of optimal marram grass take a photo every second. With a special growth has an important implication for software technique (photogrammetry) all coastal management: optimizing the Corss shore (km) 0.0 these photos could be stitched together to potential of marram grass to grow and create an accurate 3D model of the dunes. develop dunes means we can maximize the 0 1 2 3 4 5 6 Figure 4 shows two such models of the potential of coastal dunes to provide coastal Alongshore (km) same dune, from a flight day in April 2015 safety. Sand nourishment strategies such and one in September 2016. The differences as the Sand Motor should therefore aim between these models clearly illustrates how to ensure that supply of wind-blown sand Figure 4. (left) much the foredunes have been growing, towards the dunes occurs at optimal rates Aerial mapping with 0.40 especially at the dune foot, and that quite a for marram grass to thrive. Luckily, the Sand a drone to make Optimal response large number of embryo dunes have been Motor appears to do just that and in many 3D models of the developing on the beach. places on and along the Sand Motor, the foredunes. The Positive feedback dunes are developing at optimal rates. Using foredunes along Another striking finding is that the marram high-resolution data obtained by a drone the Sand Motor grass appears to be much greener on the has proven to be invaluable for gaining have been actively parts of the dunes that have been actively insight into how marram grass contributes growing and a 0.35 growing. In other words, it seems that to dune development and coastal safety. large number of marram grass is much more vital in areas The continuing application of such remote embryo dunes have that receive the most wind-blown sand. sensing techniques holds great promise to developed on the We hypothesized that this was probably better understand the coastal terrestrial

beach. the result of more vigorous growth due to ecosystem with its interactions between sand trapping, and set out to measure these the dry beach, dunes, vegetation and Figure 5. (right) differences in marram grass leaf greenness. morphology. Positive feedback 0.30 Luckily, we were able to do this because

relationship between Leaf greenness (0-1) the sensor of the camera that we used was Growing season Marram grass sand trapping modified to be sensitive in the near-infrared of wind-blown Measurement light spectrum. Because a plant absorbs sand and growth visible light for photosynthesis but strongly Response model response of marram reflects near-infrared light, there is a large

grass. Marram grass 2 contrast in reflectance which can be used to R ~ 0,92 – DUNE DEVELOPMENT grows better as it 0.25 accurately determine a plant’s vitality. traps more sand,

up to an optimal 0.0 0.1 0.2 0.3 0.4 0.5 0.6 During one growing season (April – August FOUR amount of sand per 2016), we mapped the dunes every month 98 growing season. Sand trapping (m) with our drone and using the 3D models 99 Figure 1. (below) Bas Hoonhout Visual impression of armor layer at three locations in the WHY MORE SAND NOT ALWAYS RESULTS IN LARGER DUNES Sand Motor region. Covered surface is approximately 40 x 40 cm in each case:

Intertidal beach, Bas Hoonhout obtained his PhD at the aeolian activity at the Sand Motor and the Measurements no armoring. Coastal Engineering section at the Faculty of project’s morphological development. Bimonthly measurements of the Sand Civil Engineering and Geosciences at Delft Motor’s topography show that the dry University of Technology in 2017. Currently The different constituents of the Sand beach (> 3 m above MSL) stopped eroding he has a dual position as morphologist and Motor’s sand were reasonably well mixed a half year after construction. Nevertheless, data engineer at Van Oord. shortly after construction. A large part wind-blown sand continued to accumulate of the Sand Motor is located well above in the dunes, the dune lake and lagoon. In Dissertation title: storm surge level (> 3 m above MSL), and is fact, even after the unusual aeolian activity "Aeolian Sediment Availability and therefore never inundated and only exposed stopped, three times more sand is deposited Lower dry beach, Transport." to wind. The wind exerts a drag force on in the Sand Motor area every year than minor armoring with the exposed sandy material, which can lift erodes from the dry beach. Where does this shell fragments. PhD supervisors: particles up in the air and initiate aeolian sand come from? Marcel Stive (Delft University of Technology) transport of sand to the dunes (and beyond). Sierd de Vries (Delft University of There are two possibilities: The sand Technology) The wind drag is small, especially compared can come from the low-lying beaches to the forces exerted by currents and waves. surrounding the Sand Motor (< 3 m above The size and mass of individual sand grains, MSL), or from the adjacent coast. shells and shell fragments determines the The possibility that all this sediment Upper dry beach, effectiveness of the wind to move the originates from the adjacent coast is unlikely severe armoring sandy material. In practice, only silt and as the width of the beach connecting the with many shells and fine sand grains are regularly lifted. Coarse Sand Motor to the adjacent coast is too coarse sand. sand and shells are only moved during very narrow to transport such large amounts Shortly after the Sand Motor was strong winds. Consequently, fine material of sand. Therefore, the low-lying beaches, constructed, strong winds suspended large disappears rapidly from the beach surface which are frequently flooded and up to 60% clouds of fine sediment in the air. These local and only coarse material remains, sheltering smaller than the dry beach area, appear to sand clouds could reach up to 100 m high the underlying fine material from the wind. be the primary source of aeolian sediment in and travel several kilometers inland into the Over time, the beach surface is covered by the Sand Motor area (Figure 3 on next page, urban areas of Kijkduin. About half a year a thick layer of coarse elements: the armor green shading). later, the nuisance disappeared as suddenly layer (Figure 1). as it had appeared. What happened to this This hypothesis was tested during a six- extreme aeolian activity, unprecedented The development of an armor layer explains week field campaign, during which we along the Dutch coast? why the sand clouds disappeared within counted the number of airborne sand grains a half year after the Sand Motor was using lasers. Eight masts, each of them with The sand used to construct the Sand Motor constructed. On more regular beaches, three to six laser sensors stacked above was dredged from the bed of the North Sea storm surges frequently disturb the beach, each other, were deployed in one or more and is far from homogeneous. It consists breaking the armor layer, bringing fine straight lines, aligned in the wind direction predominantly of sand (small mineral material to the surface, and reactivating (Figure 2). The masts were deployed particles between 0.063 and 2 mm in the aeolian activity. At the Sand Motor, 24 hours a day, 7 days a week for almost diameter), fine silt and clay fractions there was no such counteracting force due the full six weeks. The masts were manually Figure 2. (left) (< 0.063 mm), and coarse elements, to the fact that a large part of the Sand relocated according to the wind direction – DUNE DEVELOPMENT Measurement like shells, shell fractions, some pebbles Motor surface is well above storm surge and the tide, which required an almost

equipment with laser and cobbles and an occasional fraction level (> 3 m above MSL). This restricts the permanent presence at the Sand Motor. FOUR sensors deployed at of a mammoth bone. These different aeolian activity at the Sand Motor more If the number of particle counts increased 100 the Sand Motor. constituents appear to largely determine the permanently. from one mast to another in the direction 101 Aeolian depositon area Figure 3. of the wind, sand was picked up from the grains that are lifted from the bed are not accumulation volumes. The model captures Placement of Aeolian area between the masts: we refer to this as suspended, but are deposited somewhat the formation of the armor layer and measurement source area a positive gradient in transport. Conversely, downwind. Upon impact, each sand grain the relative importance of the low-lying equipment at if the number of particle counts decreased ejects one or more grains from the bed. beaches. However, the distribution of the the Sand Motor, from one mast to another in direction of These ejected grains gain momentum accumulated sand over the dunes, dune measured positive the wind, sand was deposited between the from the wind, get lifted, and strike the lake and lagoon is skewed a bit towards the and negative masts: we refer to this as a negative gradient bed again somewhat downwind. This dunes. Additional supply-limiting processes gradients in in transport. Analysis of the spatial variation cascade continues downwind and a thick that are currently not included in the model, transport, in transport gradients thus reveals the layer of sand grains develops, jumping in like groundwater seepage, vegetation corresponding areas of erosion and deposition of aeolian the direction of the wind. The mechanism growth, wind setup and wind steering, might aeolian source and sediment (Figure 3, detail). of saltation transport therefore implies explain these deviations. deposition areas a continuous interaction with the beach in the Sand Motor In addition, we conducted micro-topographic surface. AeoLiS provides a generic framework to domain. measurements in the low-lying beach area. implement formulations that describe We pressed about 100 small erosion pins The continuous interaction with the beach additional supply-limiting processes and (nails) in the beach during low tide, with their surface causes saltating sand grains, can be combined with existing sediment heads flush to the surface. If the low-lying originating from the low-lying beaches, to transport models to obtain a predictive beach eroded during low tide, the erosion immediately “feel” the armor layer once they coastal landscape model. Such a model can pins would protrude from the beach. Just reach the dry beach. Significant amounts be used to explore the merits of different before high tide, we manually measured how of sand from the low-lying beaches are beach nourishment designs. For example, much the erosion pins protruded to confirm trapped in the armor layer. During high the armor layer and relatively limited aeolian and quantify the erosion. tide, when no sand is supplied from the activity at the Sand Motor is largely due low-lying beaches, the wind can remobilize to its height. A lower height and more If the low-lying beaches were indeed the these fresh deposits and transport the sand frequent flooding of the dry beach might primary source of aeolian sediment, we further landward. Consequently, the strong limit the development of the armor layer expect to find protruding erosion pins and variation in particle counts near the water and stimulate aeolian activity. Similarly, positive transport gradients in this area. As line, associated with the tides, is not seen the dune lake and lagoon intercept much the low-lying beaches are flooded during close to the dunes. of the sand transported from the low- high tide, we also expect sediment supply lying beaches, limiting the possibilities for near the dunes to modulate with the tidal Model embryonic dunes to develop. If these water cycle. The analysis of spatial variation in An accurate description of the interaction bodies were smaller or in different locations, transport gradients did reveal a continuous between aeolian sediment transport and local dune growth might be stimulated. The strong positive gradient and erosion over the formation of an armor layer is necessary AeoLiS model can be used to explore the the low-lying beaches during low tide. to accurately predict aeolian sediment effectiveness of nourishment strategies However, we also measured steady particle transport and dune growth in coastal (beach, foreshore or mega-nourishment), counts near the dunes. Also surprising was environments. We developed a numerical planting and grazing strategies, beach the strong negative transport gradient model for this purpose: AeoLiS (Aeolian cleaning, raking, and prohibiting driving, Negative gradient coinciding with the start of the beach armor Sediment Transport with Limited Supply). among other things. in transport layer. This negative transport gradient AeoLiS is a model for aeolian sediment indicates rapid deposition of the sand that supply that includes the formation of armor To design a nourishment or a maintenance has just eroded from the low-lying beaches. layers and other supply-limiting processes. It strategy, proper goals of the intervention In the long run, the deposition appeared to predicts which sediment erodes and when: a need to be formulated. The primary be temporary as the armor layer (i.e., shells) spatiotemporal prediction of the erodibility objectives of the Sand Motor were to supply remained visible and was not buried under of the beach. AeoLiS does so by simulating the entire coast of Holland with sand for a Positive gradient fresh deposits. relevant supply-limiting processes, like period of over two decades and to stimulate in transport sediment sorting, development of the armor recreation in the coastal zone. Intense In order to explain what happened, we layer, and flooding and drying of the beach. aeolian activity and dune growth could need to look at the mechanisms of aeolian very well conflict with these objectives. The sediment transport in more detail. Aeolian AeoLiS was first applied to reproduce the AeoLiS model provides the tools to optimize sediment transport occurs in three stages: accumulation of sand in the Sand Motor. We coastal landscape design for tailored coastal – DUNE DEVELOPMENT Positive gradient suspension, saltation and creep. In coastal compared measured and simulated time interventions. in transport

environments, saltation accounts for the series of sand accumulation in the dunes, FOUR majority (~70%) of all aeolian transport. dune lake and lagoon. AeoLiS explained AeoLiS documentation and download: 102 Saltation is a form of transport where sand 93% of the measured variance in the total http://aeolis.readthedocs.io 103 Kathelijne Wijnberg IMPROVINGTHOUGHTS ONTHE THE ABOVE-WATER ABOVE-WATER DESIGN DESIGN OF LARGE SANDOF THE NOURISHMENTS SAND MOTOR REFLECTION

Kathelijne Wijnberg is a professor of Coastal Systems and of sand supply to the dunes. This was undoubtedly due to the lack Nature-based Engineering at the University of Twente, Faculty of of numerical models to predict above-water developments with Engineering Technology. Within the NatureCoast program she was computer simulations. the principal investigator of scientific research project S2, which focused on dune formation. It turned out that considerable amounts of wind-blown sand were trapped in the lagoon and lake (Pages 86 and 88), which was not foreseen. This affected the initial dune growth rates observed at the The core ingredient for maintaining Dutch coastal flood defenses foot of the dune reinforcement (Pages 96 and 100). The long-term is sand. This is not surprising when realizing these mainly consist effects of the trapping remain to be seen, because at some point of dunes. Initially, sand was only used to repair storm damage these reservoirs of fine, wind-blown sand will become available, to the dunes. At present, it is added once the volume of sand in as the waves and currents continue eroding the Sand Motor. an indicator zone drops below a reference value. This proactive Additionally, the seaward expansion of vegetation was affected approach was only developed because of increased scientific by activities such as raking the beaches, driving on them, and understanding of the coastal system and the processes involved construction of beach huts; this slowed down the development of a in moving the sand. new dune row (Pages 86 and 96).

With the Sand Motor pilot project, we are stepping up to the next With respect to new dune development away from the dune level. Not only by scaling up the magnitude of sand nourishment and reinforcement, valuable insight was given by the research conducted by raising the ambition that the nourishment should serve multiple by Van Puijenbroek (Page 92), who showed that the high, barren purposes, but even more so by expecting natural processes to plain of dredged sea bed material was difficult for perennial plants complete the job. In a few decades, the dunes in the region should to colonize, because root stalks transported by storms could not have been strengthened to guarantee flood safety from rising sea reach the higher elevations. Wind-blown seeds that could reach levels. In the meantime, the Sand Motor area should provide space these elevations found conditions that were too dry to germinate, for recreation and allow additional beach-dune habitat to develop and the steadily lowering bed level due to wind erosion did not help without jeopardizing the long-term goal of reinforcing the dunes. either. Without perennial vegetation, it was hard for permanent dunes to form at the Sand Motor itself. To go from voicing the bold idea of the Sand Motor, to actually constructing it has posed many challenges, one of which was how We are now finally starting to see a small incipient dune field to properly design it. Contrary to hard engineering measures, the forming on the south side of the Sand Motor. This dune field may Sand Motor is not a static intervention that needs to meet all its actually become a new local sink for wind-blown sand, meaning that goals upon completion, when the contractors have finished their it will not reach the dune reinforcement, thus locally affecting the work. The Sand Motor is a dynamic intervention where nature is sand supply to the dune reinforcement zone. actually the master builder that should ensure that all goals are met over time. So, will the long-term goal of strengthening the dunes be jeopardized by the shorter-term goals for recreation and Compared to our knowledge of below-water developments, little development of natural habitat? We certainly see an influence, but was known about how the above-water landscape would develop. to know the final effect we will have to keep following this dynamic Estimates of the magnitude of wind-blown sand supply necessary project. We will only have the scientific basis for a definite answer for dune growth as a flood defense were essentially based on past towards the end of the Sand Motor’s life span. NatureCoast research dune growth rates. Predicting how the above-water landscape at has offered advances in long-term monitoring approaches for wind- – DUNE DEVELOPMENT the Sand Motor would develop seemed largely left to artists, whose driven sand transport and predictive modeling. These consitute an

impressions often showed the Sand Motor covered with dunes important step towards improving the above-water design of large FOUR and vegetation. Apparently, developments at the surface of the sand nourishments. 104 Sand Motor were not expected to have much impact on the rate 105 JULY 2013 Ecologist and Advisor KEES VERTEGAAL – ADVISEURS ECOLOGIE

INTERVIEW

In what way is the Sand Motor unique to If you had to give advice about other you as end-user? dune areas, which lessons from the Sand "It is unique as a coastal reinforcement Motor would you use? experiment that also seeks to contribute "I think a very important lesson from the to nature and recreation. And especially Sand Motor is that you have to do more when it comes to nature. I am involved in the than just deposit sand if you want to ensure Sand Motor monitoring program through the added value mainly for nature. At Rijkswaterstaat. From there I followed the the Sand Motor, it was placing sand and NatureCoast studies, being interested in nothing else. What I have learned, and this how they supplemented our work.” has already been applied in some of our advices, is that we need to build dunes How do you see the role of scientific earlier on or stimulate development of research at the Sand Motor, as end-user? dunes more actively. If we leave it all to "Useful and necessary; much more research nature, it will become very beautiful; but should be done. I think that long-term that will take a lot of time. research in particular is very important for a project like the Sand Motor. This is because However, the Sand Motor has a limited the processes actually occur relatively lifetime, given the principle that it is slowly, and with PhD research projects designed to last only twenty or thirty years. typically lasting four years, the time span Now, the first ten to fifteen years it’s just is often too short. This applies to ecology, sand with a small dune here and there. If geomorphology, in fact, to almost all we want to enjoy it, especially in terms research topics.” of nature, we would actually have to add some more to the design and construction: How relevant is multidisciplinary research differences in elevation, planting or sowing on the Sand Motor for you as end-user? of vegetation, and things like that. To "I can be brief about that: as far as I'm a lesser extent, this is also relevant for concerned, it's almost pointless not to do this recreation, as it helps to create a landscape kind of research in a multidisciplinary way.” in which people enjoy walking. If you initially invest more in the design, you will What are the main findings of the easily create a landscape structure that NatureCoast program for you as end-user? reinforces the added value of nature "I mainly followed Marinka van Puijenbroek's much sooner.” research, which is focused on the first phase of dune development. Fortunately, this picture fits in well with what we have found in the monitoring for Rijkswaterstaat. Our work is related to that of Marinka, and her research has provided us more in-depth understanding. We mainly monitor, which – DUNE DEVELOPMENT involves limited scientific analysis, whereas

Marinka has gone into more depth and FOUR shown, for example, the way in which the 106 dunes formed and vegetation developed.” 107 DECEMBER 2013 Senior advisor, Geologist BERT VAN DER VALK – DELTARES

INTERVIEW

Why is the Sand Motor unique for you as How relevant is multidisciplinary research And you have to deal with the seasonal end-user? on the Sand Motor for you as end-user? changes, as we know them in our country, "The Sand Motor is unique to me because "Very relevant. The Sand Motor is a special especially in how the supratidal area it is a one-to-one scale experiment. That is construction; we have never seen anything develops. After 10 years you start to very unusual. I am a geologist, so I always like this on the Dutch coast in our time. That understand it reasonably, but after 3.5 years think in somewhat longer terms, and the means you have to follow it well, and that it is clouded in quite a few uncertainties. So Dutch coast has always been as straight as requires more than one discipline. Not only comparative research can be done, and I a ruler for the past 5,000 years. Note that morphology, but also ecology. For example, think that there is a lot of value to that." I’m talking about the Holland coast, not the lagoon and its development have the entire Dutch coast! And then, with the remained largely unknown to ecologists. Which research findings about the Sand Sand Motor, a large bump of sand suddenly The lagoon also makes the Sand Motor Motor can be applied to other coastal appeared: 21.5 million cubic meters. Of a unique phenomenon, because it is not zones in the Netherlands? course, the Dutch coastal system tries to found anywhere else. The new lagoon at "The Sand Motor has shown that the smooth out the coastline immediately, the Hondsbossche Duinen (Hondsbossche design of the nourishment provides a because that is how it works. This resulted Dunes) cannot be characterized as a lagoon very important starting position for future in a very exceptional situation, geologically that is more like a swimming pool." developments. This concerns the form: speaking." the Sand Motor has the dune lake and the What are the main findings of the lagoon. It was not foreseen that both the How do you see the role of scientific NatureCoast program for you as end-user? dune lake and the lagoon would absorb research at the Sand Motor, as end-user? "I think the morphological development large amounts of aeolian sand. It will "Such a unique one-to-one scale experiment is the most important one, dealing with probably take another 20 years or more must be closely monitored and evaluated, the interaction of waves and flow-driven before more dune sand lands in the coastal which is exactly what the NatureCoast transports. We can use these results as end- dunes in substantial quantities." research program has done. I think it is users; they have provided insights into the also very important that scientific research working of this unusual and large amount of "That is the big difference between the Sand continues after the NatureCoast program. sand on the Dutch coast. This also provides Motor and the Hondsbossche Duinen for Because the monitoring program that eye openers for applying large amounts of example. At the Hondsbossche Duinen much Rijkswaterstaat requires is actually not sand nourishments on other parts of the more sand ends up in the current dunes. very elaborate. And I wonder about the coast. But again, the Sand Motor is a unique And that is because there is direct contact usefulness and value of the next evaluation, case. For example, the findings of the Sand between the beach and the dune, which is from 2016-2020. It remains to be seen Motor can certainly not be compared to what happens when you apply this different whether we will actually have sufficient those of the Hondsbossche Dunes, and also design." arguments in 2020 to carry out a proper not to those of the major nourishment on second evaluation of the Sand Motor." the outer delta of Ameland."

"Continuing scientific research is not easy, "I have been investigating the upper because Rijkswaterstaat will of course waterfront of the Sand Motor, Spanjaards remain the chief management authority, Duin and the Hondsbossche Duinen, areas and they have limited funds for monitoring more than three meters above sea level, the Sand Motor. And this is where the in order to understand this part of the – DUNE DEVELOPMENT shoe pinches, because nobody will do the coast better. That is comparative research:

monitoring by himself. Maybe NWO or Spanjaards Duin is 10 years old, the Sand FOUR another financer could jump in again, that Motor 7 years, and the Hondsbossche 108 would certainly be my advice." Duinen are still very young at 3.5 years. 109 FIVE | ANIMAL LIFE – ANIMAL LIFE FIVE

110 111 Figure 1. Alexander van Oudenhoven Towards Nature Friendly Nourishment (Image by JAM Visual Thinking) THE HIDDEN ANIMAL LIFE AT THE SAND MOTOR

INTRODUCTION

As we have shown, the Sand Motor differs from other Dutch With our feet more firmly on the ground, we now reach the wet sandy beach areas because of its size, shape, the low nourishment beach, which connects the sea to the dry beach. Also called the frequency and its lagoon. This has profound consequences for the intertidal zone, this area is most directly shaped by incoming ecology of the Sand Motor. Although many might regard sandy waves. We studied the many small invertebrate animals, such as beaches as straightforward “sand flats” or “beach deserts,” they worms and insects, that somehow manage to survive these harsh are in fact highly dynamic and full of life. But this is just not always conditions. From Emily van Egmond (Page 122) you will learn more visible to the human eye. about their survival mechanisms, as well as why the Sand Motor attracts different species. Furthermore, we will show you the The construction of the Sand Motor created a lot of potential for importance of nature-friendly maintenance of the dry beach, by “new” nature. In addition, it has been suggested that the Sand Motor leaving the organic material that has washed ashore where it is. is a more nature-friendly solution than the more common smaller scale nourishments. But what kind of new nature has really been We will look at how different key animals of the four sub-systems created, and is the Sand Motor truly more nature-friendly? In this have coped since the creation of the Sand Motor. In addition, we chapter we will introduce you to four different zones, sub-systems will identify the most important factors that have determined that you might perhaps not associate with nature or biodiversity the success or demise of these species. By understanding the when walking along the shore. We will look at the sea floor, the different sub-systems as well as the Sand Motor ecosystem as a shallow sea, the wet beach and the dry beach. Each zone is affected whole, we will be able to tell more about how nature-friendly the differently by the wind, waves, currents and many other factors. Sand Motor truly is. The chapter concludes with two reflections on Naturally, the construction of the Sand Motor affected each zone animal life at the Sand Motor, as well what these findings mean for differently too. Understanding these effects, both positive and current and future coastal management. The reflection by Peter negative, will help us to conclude on the net effects of the Sand Herman (Page 126) will zoom in on the fate of macrozoobenthos Motor on nature and biodiversity. and underwater biodiversity, whereas the reflection by Rien Aerts (Page 128) will deal with the beach ecosystem. The bottom of the sea is teeming with life, which also happens to be close to the bottom of the food chain. We will look at the fascinating animal life at the bottom of the sea, as deep as around 10 meters. The worms, shellfish and other animals living here are called macrozoobenthos, and they are preyed upon by animals higher up the food chain, such as fish, crustaceans and birds. Simeon Moons (Page 114) will show you how quickly the macrozoobenthos recovered from the construction of the Sand Motor, and which other factors contributed to a different composition of species.

Moving closer towards the beach, the shallow sea waters are crucial nursery habitats for flatfish such as sole and plaice. This is where we conducted research on the effect of the Sand Motor on the habitat conditions for juvenile sole and plaice, such as the availability of food (e.g., macrozoobenthos) and the size of the sand grains.

These and other variables basically determine whether the shallow – ANIMAL LIFE sea near the Sand Motor is good enough for flatfish to grow up in.

Perhaps Marjolein Post (Page 118) will make you look differently at FIVE the fascinating life of flatfish in the shallow sea waters. 112 113 Figure 1. Simeon Moons This sample (collected near Ameland, the Netherlands) illustrates how diverse the benthic community can be. The pink color BURYING THE BOTTOM OF THE FOOD CHAIN was added for easy sorting. Diameter of the photo is 10 cm.

Simeon Moons conducted PhD research at The seaside is loved by humans, but they vegetation helps in the formation and the Royal Institute of Sea Research (NIOZ). are not the only animals attracted to it. preservation of sand dunes (Pages 88 and He currently works at Royal Haskoning DHV, Below the surface, the sea water and 92). Something similar could be happening as a marine ecologist. especially the seafloor are teeming with life. underwater, but not much is known about Often hidden from plain sight, hundreds of this yet. The underwater world is still full of PhD supervisors: different worms, shellfish, crabs, shrimps mysteries and discoveries to be made. Tom Ysebaert (NIOZ, Royal Institute of Sea and other rather odd-looking animals live Research) at the seafloor. These animals are called At the Sand Motor, we wanted to know Peter Herman (NIOZ, Royal Institute of macrozoobenthos, or just benthos (Figure 1). how the coastal benthic community would Sea Research; and Delft University of Although most of these animals are very respond when a large amount of sand is Technology) small (millimeters rather than centimeters), deposited on the seafloor. Because benthic together they make up an enormous organisms live in between the sand grains, biomass, which makes them an important they also risk being negatively affected by part of the marine ecosystem. any coastal modifications, such as sand nourishments. Sand nourishments are Benthos fulfill many functions that known to bury and suffocate local benthic contribute to a healthy ecosystem, and organisms. this in turn provides benefits to human society. Most importantly, benthos are a Sand nourishments have frequently key trophic group in the food chain; many disturbed the Dutch coastal ecosystem benthos species are preyed upon by fish, in the last decades, and they are likely to birds and even humans. Some species become even more frequent or larger, as are commercially interesting too, such as we find ways of coping with future sea-level mussels, clams, shrimps and crabs. More rise. Although the benthic community tends importantly, the fishing industry would to recover relatively quickly (generally collapse in the absence of benthos. Benthos 2 to 3 years), we would ideally like to avoid themselves feed mostly on microscopic frequent disturbance. And this is where the organisms like algae and bacteria, or on Sand Motor and its "Building with Nature" organic waste (detritus). Without them, the philosophy comes in: to limit the ecological sea would probably be a murky green soup, disturbance in time and space by applying and the seafloor would be an ecological a much larger volume of sand and using garbage dump. However, benthos do a lot natural forces to distribute the sand to more than just eat and be eaten. Because the adjacent shore. In theory, the Sand benthic organisms live in between the sand Motor would result in a longer period grains, they have the potential to act as without disturbance, which should allow “eco-engineers”: they shape the seafloor. for natural succession and eco-engineering processes. Eco-engineering can have a positive influence on other organisms, thereby An extensive monitoring program provided

increasing the biomass and the biodiversity us with yearly measurements of the benthic – ANIMAL LIFE in the ecosystem. Some “eco-engineers” biodiversity, abundance and biomass

can also benefit humans by contributing to in the area around the Sand Motor. For FIVE natural flood protection. The best known comparison, we also sampled the benthic 114 example is above ground, where coastal community on the shore of Ameland, one of 115 Figure 2. the Dutch Wadden Sea islands (see Figure 2 Sand Motor, resulting in different sediment water can change from a relatively poor A sample is taken for an impression of the sampling method). sorting. We think this diversification of the environment to a rich environment, teeming from the seafloor This island’s shoreline has a similar hook environment explains why we found more with life. with a "Van Veen shape as the Sand Motor and is similarly species overall after the construction of the Grab Sampler" dynamic, but it has been formed by natural Sand Motor than before. Moreover, we even Over time the lagoon can transform into a near the coast at processes rather than human influence. found a higher benthic diversity surrounding "green beach", with rare plant species and Scheveningen, the We also had a closer look at the effects the Sand Motor than at the naturally abundant birdlife. After additional research, Netherlands. of regular nourishments, and especially dynamic shore of Ameland, excluding we concluded that the Sand Motor lagoon shoreface nourishments (Pages 30 and 160), the lagoons. Although the area has been harbors a very high benthic diversity up since they had not been widely studied. successfully recolonized, that does not to 2 meters deep. The biodiversity is much necessarily mean that the natural system higher than at the adjacent shore, and To our surprise, we found that the benthic has recovered. Rather, it can be argued that organisms are easily accessible for foraging community can take several years to the Sand Motor has created new habitat, birds. Unfortunately, the deeper parts of recover after a shoreface nourishment, at the cost of the old. But was the original the lagoon have become oxygen depleted rather than 2 to 3 years as is generally theory not that the Sand Motor would and are therefore unsuitable for almost all assumed—and in some cases, it did not minimize disturbance to the habitat? benthic organisms. While this highlights our recover at all. The difference in recovery ability to design and build an ecologically time between beach and shoreface If we zoom out, we can see that the Sand rich environment, it also shows that we still nourishments can be explained by the Motor affects a much larger area than the have much to learn and improve. natural environmental conditions of the original nourishment surface. We discovered disturbed habitat. The deeper you move that the effects on sediment sorting extend Overall, it can be argued that the Sand into the water, the less dynamic the seafloor several kilometers along shore and to a Motor design is a step in the right direction will be, due to reduced influence from depth of at least 12 meters. These changes towards sustainable coastal protection. The wave action, and the more biodiverse the were also reflected in the composition of the lesson seems to be that if we incorporate benthic community will be. The benthos benthic community. The Sand Motor might ecosystem functioning into the nourishment near the beach might be adapted to rapid not bury the benthos in the adjacent shore, design, the ecosystem will eventually pay sediment deposition, whereas the benthos but it does change the habitat. Over time, us back. However, a simple copy-paste of at the shoreface might not. Fortunately, not the Sand Motor will shrink in size and the the Sand Motor design elsewhere could every shoreface nourishment has a long- effects on the hydrodynamics will lessen. have serious drawbacks. When considering term negative effect. The most important Importantly, we only observed this extended the fate of macrozoobenthos in sandy factor influencing the recovery period effect in the deeper waters, beyond the solutions, our findings suggest that the most seemed to be the sediment grain size; outer breaker bar. In fact, only one year after important factors are the grain size of the bigger is definitely not better in this case. construction of the Sand Motor, there were source sediment, the size and orientation Our findings underline the importance hardly any changes in benthic community of the nourishment, and, finally the shape of designing nourishments with a longer composition in the shallow water. This can of the nourishment and how this will evolve lifespan, to allow recovery to take place, and again be explained by the presence of into an ecologically rich environment. N this is exactly what the Sand Motor does. waves, which apparently makes all the other Furthermore, it would be interesting to Figure 3. factors redundant. see whether benthic “eco-engineers” can Bird’s eye view But the Sand Motor does more; it creates eventually be utilized for coastal protection. illustration of the 1 Primary dunes diversity in the landscape and habitat of There is one exception to wave dominance: ecological zones Water benthic organisms. At a regular beach, we a shallow body of water without wave Of course, the Sand Motor has just started, 2 Dry beach created by the Sand Land Regular can distinguish a number of zones with action, the lagoon (Figure 3, indicated by and it will continue to evolve for several Motor. 3 Intertidal beach specific conditions, harboring specific number 8). The lagoon is one of the Sand years. Whether the absence of frequent beach 4 Shallow subtidal groups of organisms (e.g. the intertidal Motor’s most remarkable design aspects. nourishment disturbance will truly result 5 Deeper subtidal zone, on Page 122). At the Sand Motor, From an engineering point of view, it is in a richer ecosystem remains to be seen. 6 } however, we can distinguish a number of easier to make a bell shape without a lagoon, Many questions concerning the ecological 6 Coarse sediment additional zones (Figure 3). Some are easy and it may even hamper sediment transport development of the Sand Motor remain, and 7 Fine sediment Sand Motor 7 to spot, like the lagoon, but others only to the dunes, but from an ecological point only time can tell. 7 8 Lagoon Additions 5 became apparent through research, like an of view, it makes perfect sense. The lagoon 9 Brackish lake } area with coarse sediment at the tip of the makes the Sand Motor resemble the natural – ANIMAL LIFE Sand Motor and areas with fine sediment coastline of Ameland and other dynamic 4 9 8

3 on the northern and southern side of the shores, and it is the lagoon that makes FIVE 2 Sand Motor. The coastal hydrodynamics these areas so ecologically valuable. In the 116 1 are altered by the size and shape of the absence of strong wave action, the shallow 117 Nourishment Figure 1. Marjolein Post Schematic overview of the effects of sand nourishments. FLATFISH GROWING UP IN A SANDPIT Implementing a nourishment will affect the abundance of prey species in Prey availability Sediment grain size combination with changes in sediment Marjolein Post researches marine biology The Sand Motor was established in the inhibit flatfish from burying themselves, or grain size. These and ecology for her PhD project at shallow coastal area, which provides an affect the availability of prey. In addition, changes in prey Wageningen Marine Research, and is essential nursery habitat for many juvenile prolonged digging can increase the energy availability and expecting to graduate in 2019. flatfish species, such as the commercially requirements of juveniles, which could sediment can have interesting sole and plaice. The fact that inhibit their growth and thereby make a large effect on the (Tentative) dissertation title: juveniles congregate in this habitat means them more vulnerable to predators. Habitat growth of juvenile “The effects of sand nourishments on that they are extremely vulnerable to a large degradation could thus lead to lower Juvenile flatfish flatfish such as juvenile fish.” disturbance, such as a sand nourishment. survival and fitness, as well as an overall growth plaice and sole. At present, we do not know much about negative effect on the number of juvenile PhD supervisors: the ecological impact of nourishments on flatfish that reach maturity. It is therefore Han Lindeboom (Wageningen University) juvenile flatfish and on the quality of their important to understand how grain size Martin Baptist (Wageningen Marine nursery habitat. affects flatfish in nursery areas. Research) We do know that population renewal As shown in our experiment, juvenile sole is directly linked to the size and quality and plaice prefer very fine and fine sandy of nursery areas. Juvenile growth and sediments over medium and coarse grain survival are promoted when nurseries offer sizes (Figure 2). The question remains Figure 2. suitable habitat conditions such as high whether this preference also means that These four different food availability, shelter opportunities and they are dependent on a specific habitat. sediment grain sizes appropriate sediment grain size. These Implementing the Sand Motor increased can be found around conditions are likely to be affected by the the grain size of the sediment, making the the Sand Motor. addition of large amounts of sand, as was less favorable for juveniles. We found a high The photos illustrate the case during the construction of the Sand percentage of medium-sized sand with how juvenile sole Motor. We investigated the main impacts several large patches of coarse sand around (~4 cm) can bury of the Sand Motor on important habitat the Sand Motor. This had a more prominent themselves in very conditions for juvenile sole and plaice. effect on the abundance of juvenile plaice fine (63-125 μm), This includes the effects of nourishments than on juvenile sole. The grain size on the fine (125-250 μm), on the availability of prey, sediment grain Dutch coast where the Sand Motor was medium (250-500 size, and the consequences of these implemented had already been shifting from μm) and coarse Very fine sand Fine sand changes on juvenile growth (Figure 1). fine to medium-sized sand as a result of sands (500-1000 We first investigated these impacts in an earlier sand nourishments (Page 53). If this μm). They are more experimental setting, and then attempted coarsening progresses, it could result in loss visible and less to disentangle the different effects using a of the nursery function. covered by the modeling approach. sand in medium and These effects could be amplified by the coarser grain sizes. Given that juvenile flatfish live on the bottom direct effect of the nourishment on the (Photos by Marjolein of the sea, the diameter of sand grains abundance of prey. Adding a thick layer Post) (grain size) is an important variable for their of sand results in the large-scale burial of distribution. The ability of juveniles to bury benthic fauna, with few surviving (Page 114).

in sediment with just the right size grains To facilitate rapid re-colonization of – ANIMAL LIFE is a crucial factor for habitat selection. the foreshore by benthic fauna, the

However, sand nourishment may lead to characteristics of the nourished area FIVE an overall coarsening of the sediment in have to match their habitat demands. Medium sand Coarse sand 118 the coastal zone. Coarser sediment can When a large amount of sand is added, 119 Figure 3. the new substratum may be unsuitable during their first growing season is most exceed those in outer areas, possibly due to The Sand Motor for re-colonization by the species that affected when a nourishment coincides with food limitations. lagoon is a shallow previously inhabited the area. When these high summer temperatures and the period artificial area that environmental changes are permanent, the benthic population normally increases. It was originally thought that the lagoon was created to long-term changes in the benthic The final length of juvenile plaice could would also benefit other flatfish species serve as a nursery community may also occur. drop from 8.5 cm to 6.6 cm in this scenario. such as sole, turbot and dab. However, for juvenile fish, However, if this scenario coincided with it was mostly used by juvenile plaice, offering shelter Opportunistic species usually become more a period of low benthic productivity, the indicating species-specific habitat and increased successful and their biomass increases juveniles would only reach a length of 2.8 cm preferences. However, changes in the lagoon temperatures. shortly after a nourishment event, as they by the end of summer. These represent dynamics and morphology resulted in the Over time the take advantage of the initial death of the extreme situations, and the reality will lie loss of this nursery potential in the second entrance channel benthic community. In the case of the Sand somewhere in between. Nonetheless, if year. In particular, the narrowing of the to the lagoon has Motor, this translated into high availability the juvenile’s growth is inhibited, they will entrance channel (both in depth and width; reduced in depth of prey, and as a result, high numbers of be more prone to predation, and fewer Figure 3) could have prevented fish larvae and width.(Photo juvenile sole and plaice. This suggests that will survive. This highlights not only the entering the lagoon. These results suggest by Rijkswaterstaat/ both species are able to optimize their importance of seasonal timing but also that that mega-nourishments can be applied to Jurriaan Brobbel) foraging behavior and adapt to the situation. the conditions for benthic productivity and enhance existing nursery habitats in order For instance, the fish could migrate towards recovery must be considered. to improve growth. However, the current areas with more prey if the food were design appears to be inappropriate for long- limited. Our findings also suggest that the From the perspective of a fish, nourishments term nursery creation. For the lagoon to be timing of a nourishment could affect the should ideally take place between October successful, it needs to increase in size and abundance and recovery of the species on and December, to avoid the season that the persist for several years. which sole and plaice prey. The availability population of their benthic prey grows most. of this prey will have consequences for the Sand nourishments in this period will have a We mostly focused on the effects of the caloric intake of juveniles and their growth. lower impact on benthic organisms and will Sand Motor on the suitability and quality allow the benthic community sufficient time of the nursery habitat for juvenile fish, We developed a model to directly relate to recover before the start of the juvenile specifically looking at sediment type and Figure 4. changes in the availability of benthic species flatfish growing season. Nourishments in the the availability of food. Ensuring optimal Coastal survey in following a nourishment to fish growth. spring or summer will damage the benthic habitat suitability does not necessarily 2016, fish sampling Fish growth can be optimized by increasing population, and juvenile fish that have just mean that juvenile fish will magically appear. in shallow near- temperatures and the quantity of food. entered their nursery grounds could be Nevertheless, it is important to carefully shore at Sand Motor. Thus, in our model we let temperature buried. If the sand nourishment continues consider the impacts of mega-nourishment (Photo by Marjolein and the availability of food determine the until the reproductive season, recovery of to safeguard suitable nursery habitats for Post) individual growth of juvenile plaice. The fish populations could be postponed for a juvenile flatfish and also, if possible, to model was applied for different nourishment year. These results provide useful insights on enhance these areas. scenarios that differed in the time of the how to design sand nourishment schemes year the nourishment was implemented. We and when to implement them, in order to compared the differences in growth at the protect the nursery function of sandy coasts end of the summer for each scenario. This for juvenile flatfish. enabled us to capture the most extreme effects of nourishments and to showed The development of the Sand Motor the importance of seasonal timing of provided us with an opportunity to study nourishments on juvenile flatfish growth. how sand nourishments can improve habitat diversity and ecosystem functioning. The We found that the nourishment has the Sand Motor has created a more diverse highest impact when the water temperature system and also temporarily provided an increases. Juveniles already require an enhanced nursery area for juvenile plaice increasing amount of energy to reach a in the lagoon (Figure 3), due to its higher larger body size and this is amplified when water temperatures and the shelter it

the water becomes warmer. The impact of provides. At the start of the season, we – ANIMAL LIFE a sand nourishment on juvenile fish growth, observed substantially higher numbers of

as well as on the environment as a whole, juvenile plaice in the lagoon than in the FIVE could be minimized if seasonal timing were adjacent shallow coastal area. However, 120 considered. The length that juveniles reach growth conditions in the lagoon did not 121 Figure 1. Figure 2. Figure 3. Figure 4. Emily van Egmond (top left) (top right) (bottom left) (bottom right) The polychaete The amphipod Field work at the Mesh bags worm Scolelepis Talitrus saltator in a beach in autumn. containing wrack WASHED ASHORE squamata, which patch of wrack. were placed in drift lives in the intertidal lines on the beach, zone. to perform our “litter bag” experiment.

Emily van Egmond obtained her PhD at the At first sight, few organisms or animals seem for supratidal invertebrates. In addition, Systems Ecology section of the Factulty of to inhabit the wet and dry parts of sandy it protects them against drying out and Science of the Vrije Universiteit Amsterdam beaches. The opposite is true, however: they predation by birds, and it provides space in 2018. are just difficult to find. Many organisms for them to reproduce. The invertebrate either live a few centimeters in the sand community contributes to a unique Dissertation title: or in piles of beach-cast sea weed, where biodiversity exclusively associated with “Living on the edge: resource availability and they can be found in high densities. These sandy beaches, but also supports nutrient macroinvertebrate community dynamics in organisms are mainly small invertebrate cycling and provides food for predators. It is relation to sand nourishment.” animals, such as bristle worms, amphipods, therefore crucial to understand the impact isopods and insects (Figures 1 and 2). These of the Sand Motor on the composition PhD supervisors: invertebrates are important for the sandy and assembly of the macroinvertebrate Peter van Bodegom (Leiden University) beach ecosystem, as they connect the community. In other words, does the Matty Berg (Vrije Universiteit Amsterdam) marine and terrestrial food webs. They link Sand Motor have an effect on what Rien Aerts (Vrije Universiteit Amsterdam) marine organic matter that is deposited macroinvertebrate species are found where, on the beach (e.g., sea weed) with higher and if so, why? trophic levels (e.g., fish and birds). We evaluated the development of the When looking at the beach, we can observe intertidal macroinvertebrate community a clear separation between the wet beach, at the Sand Motor for four years after or intertidal zone, and the dry beach, or its completion. We also compared the supratidal zone. Twice a day, the intertidal macroinvertebrates living in wave- zone alternates between being dry or exposed locations at the Sand Motor with saturated by sea water. Invertebrates living communities found on sandy beaches in the intertidal zone are well adapted to subject to regular beach nourishment this dynamic environment. During low tide, or without nourishment. To do this, we invertebrates dig themselves into the sand analyzed field data from three different data to avoid drying out. As the tide rises, they sets (see Figures 3 and 4 for an impression emerge from their burrows. Most species are of the field work). For the Sand Motor, we filter or deposit feeders and catch organic had data for several years (before and particles floating in the water column or after completion) at four locations. From lying on the bottom. With incoming tide, the other two data sets, we obtained data juvenile flatfish (Page 118), but also shrimp for eight nourished and six unnourished and crabs, can prey on the intertidal beaches to compare with the Sand Motor. invertebrates. Within a year of the Sand Motor’s When we move further away from the sea, completion, we already found intertidal we are at the supratidal zone, which ranges macroinvertebrate species that are common from the high water mark to the foot of the for wave-exposed sandy beaches. These dune. In contrast to the intertidal zone, this common species included the polychaete

zone is not submerged by the sea during worm Scolelepis squamata, the amphipods – ANIMAL LIFE the tidal cycle, and the sand remains dry Haustorius arenarius and Bathyporeia pilosa,

for most of the time. As food is scarce on and the isopod Eurydice pulchra. This rapid FIVE sandy beaches, beach-cast sea weed, also colonization was especially noticeable for 122 called "wrack", is an important food source Scolelepis squamata, the most abundant 123 Figure 5. of all species encountered at the Sand these conditions are present in the upper and species of macroinvertebrates present. Collecting animals Motor. When comparing different years north of the Netherlands (the Wadden Sea) We found large differences in the supratidal after sieving sand in after completion of the Sand Motor, and the lower south (the Zeeland Delta). macroinvertebrate community between summer. macroinvertebrate abundance was lower in Thus, the Sand Motor has locally given seasons. 2014 than in other post-nourishment years, rise to a habitat that attracts a different while the number of species was lower in intertidal macroinvertebrate community. Macroinvertebrates were more abundant in both 2010 and 2014. The macroinvertebrate autumn than in spring and summer, mainly community had the least variety in 2010, We compared the Sand Motor beach due to large numbers of fly larvae. The and it became more varied after completion (excluding the lagoon) with beaches number of species, however, was higher of the Sand Motor. subject to regular beach nourishment, in summer than in spring and autumn. to evaluate how wave-exposed intertidal Macroinvertebrate diversity varied during It is common to find large differences in macroinvertebrate communities differed the seasons, with the highest diversity in the community composition between across nourishment types. The number summer and the lowest in autumn. The individual years at the beach. This variation of species was higher at both the Sand most distinct supratidal macroinvertebrate may be due to the changing environmental Motor and regular beach nourishment community was found in summer, while factors on a sandy beach (e.g., average than at unnourished beaches. However, communities in spring and autumn were temperature, grain size distribution, food abundance was lower at the Sand Motor more similar. Young and old drift lines availability) or between-year differences compared to other nourishment types. showed the greatest differences in diversity in macroinvertebrate reproduction and This suggests that intertidal species can in spring, with more diversity in young survival. When comparing locations establish at the Sand Motor, but only in drift lines than in old ones. Young wrack is within the Sand Motor, the beach south limited numbers. This could be due to normally swiftly colonized and consumed of the sand hook had both the highest non-optimal habitat characteristics or by the amphipod Talitrus saltator and other macroinvertebrate abundance and highest competition for food. Furthermore, the Sand species, whereas old wrack may be less number of species. This may be due to Motor produced a slightly different intertidal palatable or of lower nutritional quality, and the sea currents that move from south to macroinvertebrate community than beaches the species may leave in search of other north along this part of the Dutch coast subject to regular beach nourishment or food sources. We conclude that there is and, hence, influence migration of intertidal unnourished beaches. The Sand Motor both seasonal and spatial variation in the species. Many intertidal macroinvertebrate differs from regular beach nourishments in supratidal macroinvertebrate community species depend on currents and other shape, size and frequency of application. at the Sand Motor. In particular, this field hydrodynamic forces for their dispersal. This may result in a range of environmental experiment stresses the importance of As a result, the southern beach might act changes (i.e., different hydrodynamic forces, leaving wrack undisturbed on nourished as a sink for migrating intertidal species, beach slope, grain size), which influence beaches and elsewhere to support a diverse which could lead to an accumulation the presence of certain intertidal species supratidal macroinvertebrate community, of macroinvertebrates. Moreover, and result in an altered composition of the especially in summer. environmental conditions may differ from macroinvertebrate community. other Sand Motor locations, with different Compared to other forms of sand sediment characteristics and more variation Supratidal macroinvertebrates can be nourishment, local disturbance to the in dry and wet beach. found in freshly deposited wrack close macroinvertebrate community was lower to the high water line and also in older, at the Sand Motor, and it also provided Our most striking finding on the partly decayed wrack in drift lines closer a new, temporary habitat for other macroinvertebrate community composition to the dunes. It is not known whether these macroinvertebrates. In conclusion, the was that a distinct intertidal community macroinvertebrate communities differ in Sand Motor created a new habitat for was present in the lagoon. This community structure, and seasonal variation of the intertidal species by increasing the spatial included the amphipod Corophium volutator supratidal macroinvertebrate community heterogeneity of the sandy beach. While and the polychaete worms Heteromastus has rarely been studied. To explore whether coastal protection is the primary goal of filiformis, Capitella capitata and Pygospio young or old wrack and season affect the most Dutch sandy shores, well-designed elegans, which are species commonly supratidal macroinvertebrate community mega-nourishments also seem promising encountered on intertidal mudflats. In composition differently, we performed a ways to support the macroinvertebrate contrast to the other wave-exposed “litter bag” experiment at the Sand Motor community of the sandy beach.

locations, the lagoon is a sheltered beach (Figure 5). We placed mesh bags containing – ANIMAL LIFE where organic matter has accumulated wrack on the beach in young and old drift

over the years. This kind of intertidal lines in the spring, summer and autumn. We FIVE macroinvertebrate community is uncommon collected the bags after two weeks, and 124 along the coast in the Netherlands. However, determined both the number of individuals 125 Peter Herman THE BALANCE SHEET OF NATURE UNDER WATER

REFLECTION

Peter Herman is a professor of Ecological Hydraulic Engineering at water exchange soon resulted in anoxia and loss of life in parts of Delft University of Technology, and senior researcher at Deltares. the lagoon deeper than two meters. Lack of water renewal in a Within the NatureCoast program he was the principal investigator for deep lagoon was an unavoidable consequence of the large sand scientific research project S3, which focused on the marine ecology movement along the sides of the Sand Motor. It is an interesting of the Sand Motor. design question whether a much shallower lagoon could have evolved faster into a green beach. This would have avoided water quality problems, but would also have created a much rarer habitat The Sand Motor is a miracle of governance flexibility. Despite the type than the one that has now developed. strict, legal constraints for coastal defence in the Netherlands, a group of visionary people succeeded in convincing all stakeholders The existing practice of foreshore nourishment regularly disturbs that this pilot was worth pursuing (Chapter 2). Value for nature the fauna in the dumping areas. Simeon Moons observed that rapid was a prominent argument. It was even stated that the Sand Motor recovery from this disturbance is possible (within a few years), on would “create nature” over vast areas, which makes one wonder locations where the grainsize composition of the sediment has not what was there before. changed. However, since the nourishment sand tends to be coarser, long-lasting changes occur if the coarse fraction remains in place. In reality, the Sand Motor was constructed in an area that was The elegant carousel experiment conducted by Marjolein Post already full of life, as one could read in the sections on benthos illustrates how juvenile flatfish dislike this coarse sand, if given the (Page 114) and flatfish (Page 118). Although the area had already choice (Page 118). It is not expected that the Sand Motor will have been regularly disturbed by sand nourishments, these did not have less effect on sediment sorting and coarsening, as it used river sand the same impact, as they were not nearly as large-scale and artificial with a considerable coarse fraction (Page 66). Thus, the Sand Motor as the Sand Motor. One could say that the Sand Motor was designed avoids disturbances but has similar or larger long-lasting effects on to be in disequilibrium with the prevailing natural forces, and to be the composition of foreshore fauna. large enough to resist nature’s efforts to clean it away for decades. The largest part of its surface was constructed as a very dry beach So, what will the natural balance sheet be in 20 years? After a that has remained almost devoid of life for the entire period. Hence, negative start, the increase in biodiversity gave a positive element. the Sand Motor started its natural balance sheet very much in the Compared with regular nourishments, the Sand Motor decreased red. the short-term disturbance to the ecology. However, assuming that sediment sorting remains the same, the long-lasting effects through But what if we focus on underwater life? Does this help to balance change of sediment may be similar or larger. In the end, the best the record? First of all, as described in Simeon Moons' contribution result we can hope for is a more or less neutral balance. Design (Page 114), the Sand Motor has diversified habitats. A temporary options to improve the natural balance are limited. The lagoon increase in species numbers shortly after construction could have could have been designed to become a green beach in a shorter been due to colonization, but even after this phase we observed a time span, but reducing changes in sediment grain composition is sustained increase in diversity. The Sand Motor has created habitats difficult. All in all, from the point of view of a worm, a Sand Motor is that normally do not occur along sandy beaches, such as the deep something one has to endure. In the end it will disappear anyway. waters dominated by tidal currents at the tip of the Sand Motor, or coarse sands kilometers away from the tip. These zones are now occupied by species that are not normally found along the sandy beach coasts of Holland, although they are not uncommon further

north and south. – NATUREFRIENDLINESS

At first, the lagoon promised to be a biodiversity hotspot, as it FIVE accumulated mud and organic material and became productive 126 for benthos and young fish. However, high oxygen loss and low 127 Rien Aerts SIZE MATTERS

REFLECTION

Rien Aerts is a professor of Systems Ecology and head of the Section to reach a fully developed community. Longer term monitoring is Systems Ecology at the Vrije Universiteit Amsterdam,. Within the clearly needed here. NatureCoast program he was the principal investigator for scientific research project S4, which focused on the terrestrial ecology of the Also interesting was that macro-invertebrate communities were Sand Motor. found higher up on the beach, living in freshly deposited wrack close to the high water line and also in older drift lines close to the dunes. These supratidal communities contribute strongly to The Sand Motor is unique, not only because of its size but also biodiversity at the higher parts of the beach, but may also help because of the time span during which the project should be to initiate dune formation due to the release of nutrients from the functional. The rationale behind this approach is that applying an wrack (Chapter 4). Therefore, beach management in general enormous volume of sand and using natural forces ("Building with (and not only at the Sand Motor) should be directed towards Nature") would reduce the disturbance to the subtidal and intertidal preserving these drift lines. zones, compared to the usual nourishment strategies, resulting in more natural succession and biogeomorphological processes. How NatureCoast was unable to consider the effect of climate change on does this work out for the macro-invertebrate community of the the ecological communities of the intertidal zone (and other zones). intertidal zone? Storm frequencies and water temperatures are expected to increase during the coming decades. Both factors will undoubtedly affect The intertidal zone, with its highly variable and often very harsh the composition and functioning of the beach communities. Clearly, conditions for natural organisms, is at first sight almost devoid further studies are needed here. of life, but a closer inspection shows that there can be abundant invertebrate life just a few centimeters in the sand or in piles of Based on the study of macro-invertebrates in the Sand Motor, we sea weed that is cast ashore (Page 122). These organisms are very can conclude several things: First, a large-scale sand nourishment important for the ecological functioning of sandy beaches. Study such as the Sand Motor is an ecologically friendly nourishment of the intertidal zone after the creation of the Sand Motor indicated strategy. Second, future designs of the Sand Motor should that, despite the initial major disturbance, colonization of the new emphasize diverse “beachscapes,” such as the lagoon. This will beach by macro-invertebrates started within a year and continued increase ecological diversity and make the nourishment function during the rest of the study period. This shows that colonization is more robustly. Third, given the highly dynamic nature of the Sand an ongoing process, which is good news! Motor and the climate, long-term monitoring is needed to see whether the relatively short-term observations obtained so far Another striking discovery was that different invertebrate are maintained in the future. Finally, the effects of climate change communities occur at different locations within the Sand Motor. (more storms, higher sea water temperatures) on the intertidal This is due to the sea currents that move from north to south along communities should be included in future studies. the coast of Holland, but also to the design of the Sand Motor, where the lagoon plays a very important role. This strongly suggests that future designs of the Sand Motor should try to create more diverse “beachscapes,” as this would increase the diversity of the beach communities.

Comparing the effects of different sand nourishment strategies

on the intertidal beach community showed that the Sand Motor – NATUREFRIENDLINESS had higher species diversity but lower numbers of individuals

than beaches subject to regular nourishments or unnourished FIVE beaches. At this moment, it is not clear if this is due to specific 128 characteristics of the Sand Motor or if not enough time has elapsed 129 JANUARY 2014 Senior scientist Marine Ecology MARTIN BAPTIST – WAGENINGEN MARINE RESEARCH

INTERVIEW

What makes the Sand Motor unique for How relevant is multidisciplinary research "New environments have also been created you as an end-user? on the Sand Motor for you as an end-user? on the exterior of the Sand Motor: with "For me the location is unique: a wide "Extremely relevant, beyond any doubt! coarser sand, steeper gradients, higher flow beach with lagoons and mudflats is a However, we have to remain cautious on what rates and erosive conditions. That results unique environment for the otherwise we call “multidisciplinary.” The average Dutch in a different species community than was closed Dutch coastline. I emphasize the citizen will often associate our ecological there before. I am not immediately saying environment because we see similar research with “research on nature.” Us that it is better or worse, because that is a ecological phenomena along all the scientists already consider multidisciplinary value judgment, but it is certainly different Wadden islands, the barrier islands in the to be, for example, one morphologist and than it was. It is still difficult for us to estimate north of the Netherlands! All the outer one ecologist that together look at how whether this is richer and more diverse deltas of the Netherlands are dynamic, dunes develop; the influence of vegetation, or not." where especially the islands form a kind of sand transport, waves and so on. The Sand Motor. This applies to the Wadden NatureCoast program considers many more "Dune growth went more slowly than islands, and also to the delta in the disciplines such as hydrology, hydraulics, anticipated, and we had also thought that southwest of the Netherlands. The design ecology and swimming safety: these different seals would rest on the Sand Motor. I have of the artificial Sand Motor at Delfland is perspectives not only increase knowledge, looked at 50,000 photos and I have only therefore based on the natural Sand Motor but also help to look beyond conventional seen one seal on the Sand Motor. I am not of the Bornrif near the island of Ameland. boundaries, and thus help to understand a pessimist, but on the topic of "ecology But also in the southwestern delta, for systems as a whole." and nature-friendly" a lot of things spring to example in an area like Kwade Hoek, we mind that start with "we had hoped that," have sand banks that behave similarly." "Translating multidisciplinary findings into which ended up not coming true. But there scientific outcomes remains extremely are always two sides to the story. Maybe we How do you see the role of scientific difficult. As is evident in NatureCoast, a would have liked to keep the lagoon open for research at the Sand Motor, as end-user? research program with a collection of PhD longer, for instance. But on the other hand "A great added value is that the students who have a very independent it is also interesting to see what is going to NatureCoast researchers have used the assignment: to write a dissertation. For such happen now. If the lagoon starts to fill up, systems of the Wadden islands and the a researcher it is complicated enough to I expect a green beach to arise there, southwestern delta as reference sites. really make one subject your own, let alone because it is already a muddy environment. They have also conducted research some other ones as well. I don't quite know a Then, for example, many salt-loving plants there, which has enabled us to make solution for this, it remains a huge challenge." will grow, very fascinating and instructive." comparisons. For example, research on the aeolian process along the coast, dune What are the main findings of the How do you see the role of ecological formation, and sediment displacement. In NatureCoast program for you? research in iplinary research projects? terms of ecological research, NatureCoast "The Sand Motor has created several new "Ecology is important in many ways in researchers have investigated the benthic environments at the coastline. The lagoon multidisciplinary research projects, because it animals and fish in this environment. The is an example. It has worked very well for a by definition already looks at other disciplines unique experiment that is the Sand Motor short time as a nursery habitat for young fish. such as geology, physical geography and has had great added value also because You normally do not have such a nursery area morphology. Ecology is also important for it has generated enormous attention for along the Dutch coastline, which is significant the public opinion, because many people

scientific research into these phenomena. because it increases the biodiversity of the are concerned with nature, biodiversity and – ANIMAL LIFE This is certainly due to the location of the coast. In the meantime you have to realize which plants, animals, birds and fish develop.

Sand Motor: close to densely inhabited and that it is temporary. For example, the lagoon You should therefore at least study these FIVE urbanized areas, easily accessible, and with is currently already too shallow so that it no phenomena to meet demands from society." 130 Delft University of Technology close by." longer functions as a nursery." 131 SEPTEMBER 2014 Senior Ecologist and Advisor LEO LINNARTZ – ARK NATURE DEVELOPMENT FOUNDATION

INTERVIEW

In what respect is the Sand Motor unique understand more about the changes in this showed a nice contrast between the for you as end-user? flora and fauna." artificial plantings at the top and the natural “Very unique. For a very long time, we have growth at the dike toe. The spontaneously maintained a fully straightened, artificial What are the main findings of the grown dune area caused the marram grass coast in the Netherlands, while that coast NatureCoast program for you as end-user? to thrive, and soon this grass at the toe was would naturally have had a less uniform "An important result for me is that having supplemented with numerous other plants shape. The Sand Motor is effectively a bulge, vegetation, seaweed and driftwood washed that naturally belong in a young dynamic an irregularity, and thus we see processes ashore and buried is an essential catalyst for dune. It was incredibly interesting to reappearing that are associated with such biodiversity on the beach. A large part of experience this happening and to tell visitors natural coasts. So the Sand Motor is enjoyed the beach on the Sand Motor is not cleaned about it, to inform them about this process very much by anyone who loves geology mechanically, which creates a much better of young dune formation and embryonic and natural processes.” starting point for nature development than dunes, why it works in some places and not on all the other neatly cleaned beaches in in others.” How do you see the role of scientific the Netherlands. In order to please beach research at the Sand Motor, as end-user? users, we often compromise and throw away “For nature conservation organizations some of the natural quality, usually without the key question is: Is the Sand Motor more being aware of it. Many people think that environmentally friendly than other coastal that there are fewer birds on the beach reinforcement alternatives? Scientific because the mechanical cleaning disturbs research is essential in gaining better them, but it might actually be because understanding of processes that take place the cleaning removes the very elements and the time frame in which they take place. that form the base of the food chain. The The research also helps us to look at the NatureCoast type of research makes those overall effects on nature. One can imagine processes more visible." that if the Sand Motor washed away in a few years, the gains for nature would be Which ecological zone of the Sand questionable and other alternatives would Motor is the most interesting for you to have been better. But if it does its job for communicate with "laymen”? twenty or thirty years, the scale will soon "The most interesting and relevant aspects tip in the direction of those gains, when of the Sand Motor, both to observe and to compared to other coastal reinforcements. explain to visitors, were the constant and This knowledge is essential and can be often spectacular changes happening to the derived in part from scientific research." system. The Sand Motor was built against the Delfland coast reinforcement, which How relevant is iplinary research on the had a horrendous sand dike with marram Sand Motor for you as end-user? grass planted in neat rows, which was slowly "This is also very important, because if fading away. After the Sand Motor was put we only looked at plants, or birds, or fish, we in place, considerable amounts of sand would only see part of the picture. accumulated against the foot of the dike,

There are many examples, but let me and a more or less natural dune started – ANIMAL LIFE highlight the inclusion of the hydrodynamic to develop. And then the marram grass

and biophysical processes driving the suddenly started to flourish in those lower FIVE ecology. The changes in salt content in parts. It was almost like it said: "Hey, this is 132 the dune lake, for instance, enable us to what I know, I belong here." For a long time 133 SIX | INTEGRATION OF RESEARCH – INTEGRATION OF RESEARCH SIX

134 135 Figure 1. Alexander van Oudenhoven When designing sandy solutions, ecosystem services offer a useful framework to integrate the different interests of INTEGRATING RESEARCH THROUGH THE ECOSYSTEM stakeholders. (Image by JAM Visual Thinking) SERVICES LENS INTRODUCTION

The versatility of the Sand Motor has been Ecosystem services are the contributions Finally, we will reflect on the usefulness repeatedly mentioned in this book. Most that ecosystems provide to human wellbeing, of the ecosystem services framework, stakeholders actually went on board with such as food, recreation, climate regulation integrated and interdisciplinary research, the project because of the multiple benefits and coastal protection. Thinking in terms of and the consequences of our findings for that the Sand Motor offered (Chapter 2). ecosystem services leads to the notion that future designs and policies dealing with As a result, in addition to “just” strengthening changes in an ecosystem lead to changes in sandy solutions like the Sand Motor. This fits the dunes for coastal safety, supplying the the benefits that people obtain from nature, directly with the final section, where we will adjacent coastline with sand addressed be they positive or negative. For instance, describe the data management system used different aims and created different reduced beach width can increase the risk of to compile all the research data gathered by expectations. These included an attractive coastal flooding and decrease recreational the NatureCoast team and more. area for nature and leisure, as well as the opportunities. Also, in the next section, we creation of knowledge and innovation. In will summarize what the first six years of other words, the Sand Motor was developed Building with Nature have brought for each as an innovative, nature-inclusive approach ecosystem service of the Sand Motor. to coastal protection that could also promote both recreation and biodiversity. Next, we will take an in-depth look at how to design and engineer ecosystem Now, almost six years down the line, these services for sandy solutions like the Sand expectations are being appraised by Motor (Page 142). We will identify the key integrating the multidisciplinary research factors that drive ecosystem services that that has been done by NatureCoast need to be considered when designing researchers and others. The previous solutions such as this. These could be chapters highlighted important advances likened to the “buttons and switches” on a in different scientific disciplines. But it is dashboard; when creating a sandy solution, only by combining and integrating these the designers and engineers need to know findings, by looking for themes that cut which to push when. Think of the shape and across disciplines and considering the elevation of the nourishment, or the grain societal implications of the research, that size and chemical properties of the sand. we can make the NatureCoast program truly interdisciplinary and meaningful. With this understanding of the factors that Therefore, we bring together findings drive ecosystem services, the next section from NatureCoast research here, some explores how these can be used to shape of which were highlighted in the previous the sandy solutions of the future. Will more chapters, some of them new. We evaluate Sand Motors be useful, or do we need to the ecosystem services of the Sand Motor rethink their shape, size and frequency? from a wider societal perspective, relate the The behavior of the Sand Motor has been findings to the original expectations of the monitored extensively in an interdisciplinary Sand Motor, and consider implications for way, feeding into NatureCoast’s integrated the design of future sandy solutions. models. These forecasts can teach us how the Sand Motor and other sandy solutions The framework or “lens” we take for this will develop over time. In this section – INTEGRATION OF RESEARCH

integration is that of “ecosystem services”. (Page 146), we have applied the model for SIX The ecosystem services framework will three alternative designs with similar sand 136 be further explained in the next section. volumes at the location of the Sand Motor. 137 Figure 1. Alexander van Oudenhoven and Arjen Luijendijk The Sand Motor provides many ecosystem services, THE ECOSYSTEM SERVICES OF THE SAND MOTOR such as recreation opportunities, coastal defense and new habitats for species of conservation interest. A unique natural landscape. A beach to NatureCoast research focused on what has solutions tend to be monofunctional, mostly strengthen the dunes. A great place to happened in and around the Sand Motor focusing on coastal protection. However, as walk the dog. The Sand Motor is all of ecosystem and what has driven these we have seen throughout the book, Building those and more (Figure 1). It provides changes. On a larger scale, conditions and with Nature as a design philosophy considers different benefits to people, and people processes, such as soil and water quality, multiple functions and ecosystem services. perceive those benefits differently as well. sediment transport and dune formation It considers, just like in our framework, the Collectively, we refer to the contributions were studied. On a smaller scale, specific drivers of ecosystems, as thus closes the that the environment provides to people as biotic and abiotic characteristics of the Sand circle, as we see in Figure 2. “ecosystem services”. Ecosystem services Motor were studied, such as sediment size are the link between nature and society, and chemistry, and specific plant and animal We have adopted this framework because between ecosystems and our wellbeing. For species. ecosystem services are widely discussed in instance, dune ecosystems are beautiful to relation to Building with Nature or nature- hike in, but also protect millions of people The Sand Motor is highly dynamic, so the based solutions in general. However, few against rising sea levels, while at the same previously-mentioned conditions, processes studies and projects truly evaluate the time filtering and storing large amounts of and characteristics are constantly changing. designs of sandy solutions in terms of drinking water. A change in the condition of This is a result of drivers, such as the tide, ecosystem services. In the remainder of dunes would therefore result in considerable waves, wind and current, the natural forces this chapter, we will look in detail at the changes to human wellbeing. that shape the Sand Motor, and which are ecosystem services that the Sand Motor central to Building with Nature. provides. If we look at the Sand Motor from the point Figure 2. DESIGN of view of ecosystem services, we can The ecosystem services are central to the Key ecosystem services for policy actors The ecosystem assess the “success” of the Sand Motor in framework, as they link the ecosystem to It is important to remember that ecosystem services framework Engineering terms relevant to society. It also allows us society and its wellbeing. The latter can be services go beyond scientific assessment. of NatureCoast. The to identify which ecosystem services would expressed and measured in terms of safety, Scientists should not decide which ecosystem framework connects change, if certain features of the Sand Motor health, employment, welfare and sense of services are important, but they can help what happens in DRIVERS ECOSYSTEM EVALUATION were to change. In this chapter, we integrate place. While these might appear vague and to understand how society ultimately views the ecosystem to SERVICES the research findings of NatureCoast under imprecise to the natural scientist, we must these services, which it considers important, consequences for the “umbrella” of ecosystem services. To not forget that many political and personal and why. This inspired us to go back to the human wellbeing Coastal defense measure the success of the Sand Motor, we decisions are based on such measures. interviews that Ewert Aukes and Lotte Bontje and how this can will look at the ecosystem services it offers This evaluation step is of course a lot more (Chapter 2) conducted with key policy actors be incorporated Recreation and will put them in context by relating complex than illustrated in the figure, as was who were involved in the startup of the pilot into future designs ECOSYSTEM WELLBEING them to the original aims of the pilot Sand clearly shown in Chapter 2. Moreover, it can Sand Motor. In these interviews, the actors of sandy solutions. Nature development Motor. involve many different stakeholders and can shared how they experienced the governance Note that the first Conditions Safety thus go beyond political decision making. process but also expressed what motivated four ecosystem Learning by doing The ecosystem services framework them to go on board with the pilot project. services, in thicker Processes Welfare Figure 2 gives a schematic overview of The strengths and weaknesses of the These motivations were mostly in line with boxes, correspond Drinking water the interdisciplinary ecosystem services solution or system at hand, be they the original aims of the Sand Motor, but to the original aims (A)biotic Health framework, which can be applied to economic, societal, physical or cultural, we also discovered important additional of the pilot Sand characteristics Habitat for flatfish designing and engineering sandy usually have consequences that can motivations. All of them could, however, be Motor. Identity solutions. We will go through it step by be considered for future designs and expressed in terms of ecosystem services. Inspiration for art step, starting with the ecosystem. In the engineering solutions. The design can be We also found that policy actors used broad – INTEGRATION OF RESEARCH

previous chapters, we explained that the altered, for instance, if more recreation and ambiguous terms, which have to be SIX Cultural heritage Sand Motor can be seen as an ecosystem, potential is desired, or if there are safety clarified and defined if we are to assess them 138 albeit manmade and managed. Most of the concerns. Note that most hard engineering scientifically. 139 Figure 3. (below) Figure 4. (far below) Of the twenty categories of ecosystem to 40% of the visitors coming from outside morphology, ecology and other aspects. like the Sand Motor. The same could be Opportunities for recreation constitute one The main success points of the Sand Motor: services that are commonly used, only four the province of South Holland. All in all, it is NatureCoast itself is a prime example of said about habitat provision for flatfish and of the main success factors of the Sand responses from people attending the final were regularly referred to by the policy fair to say that recreation is definitely one how the project has contributed, as we other species, even though this was not a Motor, with up to 5,000 people visiting on a NatureCoast symposium. Note that the actors: coastal defense, recreation, nature of the main success factors of the Sand have shared knowledge at over 30 different prime consideration in the design of the busy summer day. highest scores go beyond physical aspects. development and “learning by doing”, Motor, although the diversity of recreation scientific events, by engaging with the Sand Motor. Sandy solutions could play a or knowledge development. Let us first opportunities is challenging to manage, and general public, and through around significant role in providing a nursery habitat summarize how these four have fared over the kite surfing opportunities are dwindling 40 scientific publications (Page 200). Due to for juvenile fish, with many species having the last years. as the lagoon shrinks. its shape, size, multifunctionality and its aim high commercial and conservation value. to contribute to knowledge, the Sand Motor Policy actors referred to coastal defense Nature development was often referred to has become an icon of coastal management. Perhaps surprisingly, we end with two in quite general terms, but note that in combination with recreation. The two This is perhaps best exemplified by the cultural ecosystem services that have been the Sand Motor has contributed on two were even combined as one of the original sheer number of excursions that were experienced but were not actually studied different, albeit interrelated fronts. First, aims of the Sand Motor. However, the Sand hosted by NatureCoast, Rijkswaterstaat, the by NatureCoast. The Sand Motor is a cultural it was designed to spread sand in both Motor shows that nature and recreation province of South Holland and many other phenomenon as well as a physical and northern and southern directions, and only go together in moderation. Dune involved partners - between 50 and 100 natural one. It has served as an inspiration thereby widen the beaches and prevent vegetation has suffered from recreation excursions per year. These were requested for art and design, as well as contributing to erosion. Wider beaches absorb the energy pressure and, conversely beachgoers do and attended by delegations from all over cultural heritage. First, as the Satellietgroep of incoming waves, especially during storms, not appreciate the muddy lagoon and its the world, which means that the knowledge showed (Page 156), the Sand Motor has which makes sandy beaches the first line smell. If we were only to evaluate the Sand gained here has been shared all over the sparked an ongoing dialogue between art, of defense against coastal flooding. Sand Motor based on nature development, it world too. Taken together, the showcase science and the general public. On top of transport by the Sand Motor has been close is clear that the project could have done effect of the Sand Motor, the fact that it that, the Sand Motor has been hailed as to optimal, with around 4 million m3 of sand better, although it is still a young project had never been done before and that we quintessentially Dutch, a leading example of having been transported in the first five from an ecological point of view. There is can learn from it account for a major part innovative coastal management, as well as years. Second, the Sand Motor contributed no doubt that a large area of new nature of its success (Figure 4). This cannot always just a beautiful place to be. Policy makers, to coastal defense by strengthening the has indeed been developed, and with it be replicated in the future; five more Sand scientists and beachgoers seem to share a dunes. Both the height and volume of a great diversity of habitats and species, Motors would not be especially innovative. strong sense of pride about both the Sand the dunes have gradually increased, after including many with conservation value. The However, explicitly combining innovation Motor itself and the process that led to it. a delay of several years. In addition, the fact that the lagoon currently still harbors and developing knowledge seems a feasible A few quotes from the final NatureCoast formation and dynamics of embryo dunes a higher variety of benthic species than and worthwhile approach, both from the symposium illustrate this: “It can be seen across the Sand Motor are a clear indication the Wadden Islands has gone practically point of view of scientists, practitioners and from space!” “We should be proud of what that natural dune formation has been unnoticed. Put together, this should make policy makers. we have achieved.” “This could only work in possible, though not without challenges. it a considerable success from the point the Netherlands.” “It has put us back on the of view of policy actors. However, Chapter Surprise! Unexpected ecosystem services world map of coastal management.” The Sand Motor offers a unique variety of 5 showed that ecologists have divided Based on NatureCoast research and our Nature development opportunities for recreation. However, just opinions, depending on which aspect and overall experience, we can identify at least Pride, innovation, knowledge development as with coastal safety, we need to distinguish sub-system they are evaluating. Clearly, four other ecosystem services that were not and cultural heritage (Figure 4). These specific categories in order to truly “nature” encompasses many different explicitly targeted or mentioned during the are not the usual terms that end up in a Dune development understand the Sand Motor’s contribution. aspects, ranging from a nice landscape to design or initial phase of the Sand Motor. cost-benefit analysis evaluating coastal Research conducted for the province of the diversity of benthic species to the one Applying the ecosystem services framework infrastructure. However, it would be foolish South Holland found that a third of the seal, photographed once, that continues to can help to identify aims that could be to discount these non-tangible outcomes, Innovation people who visit the Sand Motor come to appear on official communication channels. included in future sandy solutions. A great and without them the Sand Motor might not walk, whereas a fourth come to swim, and From an ecological point of view, the Sand example is kite surfing, which is currently even have been built. Even so, the next Sand most of the others come to visit one of the Motor could have clearly done better. hailed as one of the greatest success of the Motor or sandy solution will not be a pilot Coastal safety beach restaurants and cafes. Other activities Sand Motor, even though it was not referred anymore; it will have to be designed based include, in decreasing levels of popularity, One of the unique features of the Sand to by a single policy actor at the start of the on solid insights on what will happen, and kite surfing, jogging, flying kites, biking and Motor has always been the learning by project. which ecosystem services will be promoted Interdisciplinary collaboration sailing. On a busy summer day, up to 5,000 doing aspect, which is something that or affected by the design. Therefore, the people visit the Sand Motor. According was embraced by all who were involved. The freshwater lens under the Sand Motor next chapter will focus on the characteristics Showcase effect to interviews, visitors especially enjoy the The consortium behind the project has has continued to increase, potentially on which the ecosystem services of the quietness and the vast space, as well as the always had the explicit aim of innovating providing drinking water for over 8,000 Sand Motor depend. opportunity to unwind. Interestingly, many and learning from the unknown. This might households per year. Research by Sebastian – INTEGRATION OF RESEARCH

0 2 4 6 8 10 12 14 16 18 people also visit the Sand Motor out of not sound like an ecosystem service, but Huizer (Page 66) clearly indicates that SIX curiosity; they want to see it for themselves if you think about it, we are learning a lot providing freshwater can be considered 140 Number of responses and often travel quite far to see it, with up from the Sand Motor, its behavior regarding an added benefit of mega nourishments 141 Arjen Luijendijk and Alexander van Oudenhoven ENGINEERING THE ECOSYSTEM SERVICES OF THE SAND MOTOR

To actually design for sandy solutions, embryonic dunes to form. If these water the lagoon promised to be a biodiversity designers need to know the key factors bodies had been smaller or in different hotspot, as it accumulated mud and organic that drive ecosystem services. This section locations, local dune growth might have material and became a productive habitat will look at the key factors that drive the been stimulated. The long-term effects of for benthos and young fish. However, three main ecosystem services of coastal the trapping remain to be seen, because at after some years, high oxygen loss and defense, recreation and nature development, some point these reservoirs of fine, wind- low seawater exchange soon resulted in followed by a description of how to evaluate blown sand will become available, as the anoxia and loss of life in parts of the lagoon these. Finally, an example of arguable the waves and currents continue to erode the deeper than two meters. A shallower most important design factor is discussed. Sand Motor. lagoon could have evolved faster into a green beach, which would have created Drivers of the main ecosystem services Recreation a much rarer habitat type than the one Coastal defense The Sand Motor has become a hot spot for that has now developed. Furthermore, The dunes landward of the Sand Motor kite surfers, due to relatively flat waters in the lagoon side of the Sand Motor has need to grow to increase coastal safety the lagoon combined with an undisturbed created a location where fine materials, from flooding. Sediment composition will sea wind; in addition, the neighboring open like clay particles and organic material, can determine how effective this process is; waters provide more challenging conditions. be deposited. This material attracts soil this involves the mean sediment diameter, A design without a lagoon would not have organisms related to a tidal flat, but it can the sediment grading, and the presence attracted kite surfers, although other also bring contamination. Even though the of shells (Figure 1). Simulations suggest beachgoers seemed complained about the contamination is relatively low and harmless that if shells had not been present in the smells generated by the lagoon. to humans, it might hinder soil organisms nourished sand, much more sand would from creating large populations. have been transported from the crest of Swimmer safety can be increased by the Sand Motor. In addition, the Sand Motor minimizing tidal eddies and rip-currents. Research into benthic species has shown developed an armor layer which resulted This can typically be achieved by reducing that they can recover rapidly from such a in relatively limited wind-blown transport bathymetry gradients as well as preventing large disturbance (within a few years) as activity. This was largely due to its height. alongshore variability in sandbar dynamics. long as the grain size composition of the If the Motor had been lower and the dry To some extent, this can be engineered sediment has not changed. However, since beach had experienced more frequent by changing the size and shape of the the nourished sand in the Sand Motor is flooding, the development of the armor nourishment, the bathymetry and grain coarser, long-lasting changes will occur layer might have been limited, thus diameter of the nourished sand. Of course, if the coarse fraction remains in place. As stimulating aeolian activity. Similarly, the catering for such various recreational the Sand Motor is expected to continue to dune lake and lagoon intercepted much activities requires many physical and social act as a “sediment sorter”, this could have of the sand transported from the low- factors to be considered, and this leads to long-lasting effects on the composition of lying beaches, limiting the possibilities for tradeoffs. The sheer size and uniqueness of foreshore fauna. Selecting an appropriate the Sand Motor seem to be the main factors sediment size and composition for a driving recreation; however, in future nature beach nourishment are key factors for the development and suitability for recreation development of the marine ecology. Figure 1. (left) need to be explicitly considered when Photo of the designing sandy solutions. Study of the intertidal zone after the variation in grain creation of the Sand Motor indicated that size diameter of Nature Development macro-invertebrates started to colonize – INTEGRATION OF RESEARCH

the nourished sand The Sand Motor has created habitats that the new beach within a year and continued SIX taken at the cliff do not normally occur along the linear throughout the study period. Another 142 (Photo by Iris Pit) sandy beaches of the Dutch coast. At first, striking discovery was that different 143 Figure 2. Figure 3. Figure 4. (far below) invertebrate communities occur at different implemented - the one that provides the mechanisms of the tides, waves and wind Predicted Time series of The many relations locations within the Sand Motor. This is due best combination of desired ecosystem cause sediment sorting processes to act bathymetric the predicted of the sediment to the currents, but also to the design of services. upon the nourished sand. The sediment size evolution between development of grain size and the Sand Motor, with the lagoon playing and composition were found to influence 2011 and 2040 the surface area composition to a very important role. To increase the We found that most ecosystem services are everything from the communities of marine of the present of the sheltered other processes diversity of the beach communities, future driven by factors that can be captured in benthos, fish, plant colonization, wind-blown Sand Motor. subtidal ecotope and aspects at the designs should try to create more diverse hydro- and morphodynamic models. Hence, transports, the formation of embryo dunes, (lagoon area). Sand Motor. “beachscapes”. to quantify and evaluate the ecosystem development of vegetation, the dynamics in services we applied numerical models biodiversity in the lagoon, the potential for Research on new dune development away to predict the morphological changes green beaches in the lagoon, the potential Sheltered subtidal from the existing dunes showed that the over time. Field-verified predictions still for contamination, morphological behavior, 7 high, barren plain of dredged sea bed show clear remainders of the Sand Motor and even recreation. 6 material hampered perennial plants from along the coast in 2050 (Figure 2). As 5 colonizing, because root stalks transported sandy solutions will change over time, it 4 3 by storms could not reach the higher is important to realize that the different 2 15 elevations. Wind-blown seeds that could ecosystem services will also change. 1 reach these elevations found conditions that For example, the predicted ecotope (a 0 -1 were too dry to germinate, and the steadily landscape feature), representing the 2011 -2 lowering bed level due to wind erosion sheltered subtidal lagoon area, shows -3 10 -4 did not help either. Without perennial that the surface area of the lagoon will -5 vegetation, it was hard for permanent diminish over time reducing the kite surfing -6 dunes to form on the dry beach. Thus, the opportunities (Figure 3). In addition, the -7 sediment composition and crest height are beaches towards Scheveningen harbor -8 Ecotope area (ha) 5 -9 two important factors that affected the will become significantly wider. This will -10 development of vegetation at the Sand be disadvantageous for beachgoers as -11 -12 Motor. Another surprising factor is the effect the walking distance to the water line will 2016 0 of human behavior. The seaward expansion become much longer. 2010 2020 2030 2040 2050 of vegetation was affected by activities such Years as raking the beaches, driving on them for When comparing alternatives for sandy supervision and research, and construction solutions, the focus should not only be on of beach huts; this slowed the development the initial impact on the most important of vegetation and new dunes. ecosystem services, but also consider how these are affected at various time points All in all, “nature development” covers many in the project’s lifetime. Adding the time 2030 Vegetation different facets of the vast and complex dimension into the design phase provides development Sand Motor ecosystem, and there are even more opportunities to truly integrate Marine many factors behind these developments. and (potentially) optimize the ecosystem benthos Although using a broad term like “nature” services. This, however, demands a sound Plant will get many stakeholders on board, understanding of how these services behave colonization designs for sandy solutions should have over time and what drives them. Formation of specific ecological aims that can be readily young dunes monitored. All these factors need to be The influence of sediment size and Recreation 2040 incorporated when designing and evaluating composition Sediment Building with Nature solutions with specific The NatureCoast research has clearly grain size & emphasis on nature development. illustrated the complexity of the Sand composition Potential for green beaches Motor’s behavior in space and time. Many Wind-blown Evaluating ecosystem services over time interrelations were found that could transports Fish To truly achieve solutions that offer only have been identified by combining ecosystem services along our coasts, we knowledge across various disciplines. The Potential for would need to integrate coastal defense, most telling example is how sediment size – INTEGRATION OF RESEARCH Morphological Dynamics in contamination recreation and nature development and composition has influenced the Sand

behavior lagoon biodiversity more comprehensively. Only then can an Motor’s morphology and ecology and SIX optimal sandy solution be designed and thus the ecosystem services. The driving 144 145 Figure 1. Arjen Luijendijk and Alexander van Oudenhoven Predicted bathymetries for the reference case (the Sand Motor as constructed in 2011) and three alternative designs; SHAPING FUTURE SANDY SOLUTIONS Alternative A - the lowered Sand Motor, Alternative B - the mirror-image version of the Sand Motor, and Alternative C - the wing-shaped island.

The behavior of the Sand Motor has been intertidal flats. To demonstrate the impact among the designs. Based on the decadal monitored extensively in an interdisciplinary of a few of these design parameters, we predictions, the lifetime of the Sand Motor way, feeding into NatureCoast’s integrated predicted the 20-year evolution of different will easily exceed twenty years and could be numerical models. Applying these models alternative designs (Figure 1) by applying a as much as 40 - 50 years. This means that enables us to forecast the future changes Delft3D model. The main message that we it is worth putting time and effort into the of such sandy solutions. This section wish to convey here is that the hook shape is design of such a prolonged sandy solution. Reference Alternative A Alternative B Alternative C demonstrates the impact of three design just one of the possible shapes and designs. parameters on the predicted evolution over A Sand Motor is not per se a hook-shaped For other sites in the world where a sandy a period of 20 years. beach nourishment, but a concentrated solution is being considered, it is important nourishment that feeds the adjacent to realize that the ratio between the Understanding the factors that drive beaches at a rate that is in pace with the nourishment volume and the sediment ecosystem services (as discussed in the natural dynamics. transport capacity (determined by the previous sections) allows us to better shape natural forces of tide, waves and wind) will new sandy solutions. We can change the For alternative A the present Sand Motor differ. The latter determines the dispersion shape, size, and elevation, and add features has been lowered by 2.5 m. The hypothesis of the sandy solution over time, its final After 2 years After 2 years After 2 years After 2 years like a dune lake, lagoon, or small inlets. After was that the crest would then be flooded footprint, and its lifetime, all of which need this, we can apply the numerical models during storms, thereby showing more to be considered when the goals of the to forecast the morphological behavior of dynamics. The second column (of Figure nourishment are being determined. the sandy solution, both under and above 1) confirms this and shows that the lagoon water. In this way, the design tools can be area would be larger for the first 5 years developed, tested and made available for compared to the reference case. Alternative application. But when considering such a B illustrates what would happen with a multifunctional coastal intervention, the mirror image of the hook-shaped peninsula starting point for the design will always be (third column in Figure 1). Surprisingly, After 5 years After 5 years After 5 years After 5 years a main goal, or more often a combination the model prediction shows that a lagoon of goals. with comparable size would develop as that in the reference design. Alternative The province of South Holland played a C starts with a different design: a wing- crucial role in the development of the design shaped island. Such an island could promote of the Sand Motor. From the point of view recreation (boats could visit the island) and of coastal safety, there was no need to would create a large lagoon over time, which place sand above water, but these offered is clearly visible in the predictions up to 5 opportunities for recreation and nature years. After 20 years After 20 years After 20 years After 20 years development. As the province promoted these goals, a design that included After 20 years, the predicted shapes of all above water elements was preferred and four designs are generally not that different. implemented. The natural forces tend to smoothen the Bed levels (m w.r.t.MSL) coast back to its original orientation and Many design parameters can be varied when spread the sand along this stretch of designing a sandy solution, for example, the coastline. This tells us that if we think in -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 volume, size, shape, orientation, elevation, terms of decades, the initial design becomes – INTEGRATION OF RESEARCH

slopes, grain size, sediment composition, less important, although differences still SIX chemistry of the sand, groundwater table, occur at a more detailed level; for example, 146 and features like the dune lake, lagoon, and the lagoon area after 20 years differs 147 Peter van Bodegom ECOSYSTEM SERVICES: AN UMBRELLA CONCEPT TO ESTABLISH INTERDISCIPLINARY LINKS REFLECTION

Peter van Bodegom is a professor of Environmental Biology at the the nutrient cycle. Each of these aspects reflects a (potential) Institute of Environmental Sciences at Leiden University. Within the ecosystem service. Ecosystem services can thus act as an umbrella NatureCoast program, he was the principal investigator for scientific concept to understand the interdisciplinary links between all these research project I1, which focused on integrating the program’s aspects relevant to nature-based solutions, as was studied in the research findings. NatureCoast project.

To truly achieve ecosystem services-based solutions along our When the development of the Sand Motor started, the concept coasts, however, we would need to integrate these aspects more of ecosystem services (Page 138) had not yet been explicitly comprehensively. For each coastal challenge, stakeholders, whether mentioned in the various policy documents. Instead, the Sand governmental organizations or companies and NGOs, will have Motor was introduced primarily as a new way to protect our coasts different demands regarding the necessary ecosystem services, against soil erosion, by using the forces of nature. Based on this since societal and physical conditions differ in each location. concept, nature would be used to do what it is good at: changing Those demands represent one way to express the value of the the landscape. In fact, this aspect of building "soft" solutions based ecosystem services, and may be preferable, as monetary valuation is on ecological processes has been strongly emphasized to advocate complicated at best. Based on those demands, an optimal solution nature-based solutions for coastal defense. However, coastal - namely, the one that provides the best combination of desired protection is just one ecosystem service. ecosystem services - can be designed and implemented.

Soon enough, it became clear to policy makers that the concept of This optimal solution could be very different from the nature-based nature-based solutions could be broadened to more than coastal solutions we have seen so far. The actual difference will be hard to protection alone, and that a whole suite of functions or services predict beforehand, as all solutions currently assume that coastal could be achieved through nature-based solutions, which might defense is the prime ecosystem service being demanded. This in turn increase the acceptance of the proposed solutions. When assumption also complicates evaluating the physical properties interviewing policy makers about what they considered the policy of the Sand Motor, which are almost by default considered to be objectives of the Sand Motor, many mentioned coastal protection, more important than properties and benefits associated with other next to nature and landscape (which fits in the concept just services. Thinking of new ecosystem services-based solutions, which presented), but they also indicated the importance of recreation and consider a multitude of demands and are potentially based even knowledge development. The research described in the beginning on a transdisciplinary approach, can be exciting. However, such of this chapter (Page 138) showed that policy makers had various solutions should always be based on an understanding of how aspects of ecosystem services in mind when considering coastal the system functions from a physical, ecological and societal point solutions. Indeed, the concept of ecosystem services (defined here of view. And this is exactly where NatureCoast has provided a as the benefits people obtain from ecosystems) may be seen as a solid base. framework that unites and integrates the various functions that have been studied in the NatureCoast program.

The combination of sand deposition below the water surface and dune formation ensures sustained coastal protection. The Sand Motor has also become a national hot spot for kite surfers, and attracts recreational visitors in every season. It impacts on local hydrology (Page 66) to provide water regulating services, and it serves as a fish nursery, as investigations on fish stocks showed – INTEGRATION

(Page 118). Many ecosystem services of sandy beaches demand the SIX support of well-functioning food webs in the subtidal and intertidal 148 zones to provide food for fish, sequester carbon, and to regulate 149 Figure 1. (right page) Kees den Heijer The data stages as defined by the OpenEarth philosophy. SAND MOTOR DATA MANAGEMENT SYSTEM Figure 2. (below) Screenshot of the interactive viewer of Sand Motor data. SPECIAL

Kees den Heijer is a senior researcher at Deltares and Data Steward The 4TU.Centre for Research Data, Delft University of Technology at Delft University of Technology. Within the NatureCoast program, and Deltares collaborated to create a data management system he was responsible for the Data Management system designed to be to store and share the Sand Motor data. The data management compatible with OpenEarth. approach was based on the OpenEarth philosophy, with transparency, version control, international data standards, and sharing as key principles. The Sand Motor is the first project of its kind in the whole world and has thus attracted both national and international attention Figure 1 shows the data stages defined in the OpenEarth philosophy. from researchers, policy makers and the general public. Valuable All raw data is stored in a version-control system, which keeps track data has been collected by Rijkswaterstaat through the Monitoring of the history of all files, including what was added and modified and Evaluation Plan, and by researchers of NatureCoast and other by which user and when. The scripts are also stored together with projects. All data is publicly available via https://zandmotordata.nl. the raw data, to process it to standard data and higher stages. The catalog gives insight into the availability of the data at all stages. All The preparation, design, and construction of the Sand Motor, as data is publically available, from standardized data and upwards. well as its development over time, has been the subject of research Access to raw data can be granted upon request. by multiple disciplines, ranging from technical to environmental and social sciences. Integrated research is especially important to Generating standardized data not only stimulates reuse across the NatureCoast program, and this requires proper sharing of data disciplines, but also simplifies its presentation to a variety of across all involved disciplines. Terminology, measurement methods, audiences, for instance using an interactive viewer, as shown in or abbreviations that might seem obvious within one discipline are Figure 2. not automatically clear to people from other fields. Hence, sharing data across disciplines sets additional requirements to the level Finally, in the Sand Motor data management, we paid attention to of standardization and documentation. The project was able to the FAIR principles: stimulate cooperation and integrated research by making the data - Findable, via a catalog publicly available and by paying special attention to the terminology - Accessible, by sharing the raw data and making the standard data used across the different disciplines. publicly available - Interoperable, by adopting international data standards - Reusable, by adopting data standards and providing interactive viewer functionality – INTEGRATION SIX

150 151 Satellietgroep SAND MOTOR: A CULTURAL PHENOMENON

SPECIAL

Photos: left to right, top to bottom: Satellietgroep redefines and explores the Sand 1. Artistic research Sand Motor: The Culture of Motor as cultural phenomenon, reflecting on Nature. Photo Jacqueline Heerema. the impact of the Sand Motor in the context of 2. Sand Motor, quote Satellietgroep: “The Dutch artistic research in polders, Wadden Sea and are masters in disguising a cultural landscape islands and international exchange projects. as a natural one. We tend to design, construct, The artists collective hosts artists in residence reconstruct and deconstruct nature to fit our for artistic fieldwork and creates conditions to needs." Photo Jacqueline Heerema. collaborate with local experts and scientists. 3. Public Expedition Zandmotor #1: Sand Drift, Together they develop new concepts and artist Zoro Feigl: Untangling the Tides. works that explore the sea, coastal transitions Photo Thijs Molenaar. and climate change in past, present and 4. Building with sand, Beach Rock TU Delft. future. In collaboration with artists, designers, 5. Public Expedition Sand Motor #2: students, pupils, local experts and scientists, Cultural Geology. Satellietgroep creates a growing Sand Motor 6. Public Expedition Sand Motor #3: Collection. During Public Expeditions on artist Berndnaut Smilde: Breaking Light. the Sand Motor audiences are engaged Photo Annegret Kellner. with these visual narratives. The works and 7. Climate Experiment Sand Motor #6: insights gained are presented at international artist Esther Kokmeijer: Climate Proof. art exhibitions and coastal conferences. How climate adaptive is mankind? Photo Society needs engaged artists and passionate Esther Kokmeijer. scientists to jointly test our perceptions to 8., 9. & 10. artist Sarah Cameron Sunde (USA): raise public and professional awareness. 36.5 / A durational performance with the sea (8) Art meets science: 1. Photo Jacqueline The Sand Motor can be regarded as the largest Heerema. cultural statement regarding the shifting (9) Art engages audiences: 2. Photo Florian relationship between people and water of this Braakman. time. All issues related to climate variations, (10) Art engages policymakers: 3. Photo perceptions of time and place, culture and Florian Braakman. nature come together. An in-depth reflection on 11. Zandmotor ZandGlas by Atelier NL. Photo the Satellietgroep line of thought is developed Teun van Beers. in the essay “Who is nature?” The artists explore 12. Design ZandGast, public information center and explain how visual narratives in art and Sand Motor by RAAAF, Atelier de Lyon icm design can overturn prevailing understandings TU Delft, 2016. of environment. They draw from their own 13. Public Expedition Zandmotor #10: Walking experiences and projects on the Sand Motor to a timeline of 10.000 years coastal history, illustrate the statement and to explain how they Solleveld & Zandmotor. Photo Theo Mahieu. came to the question “Who is nature?” 14. Cultural Geology, artist Theun Karelse: Fossils Soup. Photo: Florian Braakman. Now that people all around the world are slowly 15. Public Expedition Zandmotor #16: artist starting to rethink how people and planet are Maurice Meewisse: Eight Working Hours interrelated, new questions arise around the – INTEGRATION

16. Satellietgroep, A Taste of the understanding of time and the perception of SIX Anthropocene, international exchange place. It is not merely a technical or political 152 Sand Motor - New York City. challenge that we are facing. It is a cultural one. 153 MAY 2015 Policy officer Asset Management Technology PATRICK BACON – DUNEA

INTERVIEW

In what way is the Sand Motor unique for How relevant is multidisciplinary research you as end-user? on the Sand Motor for you as end-user? “The Sand Motor has put a profound “For Dunea, multidisciplinary research and far-reaching external pressure on is important, because our assets can be our drinking water production. At the affected on various scales, and by multiple location, we have dunes that actually causes simultaneously. Whether the effects contain polluted debris, which were are on the ecology, hydrology or bring dumped after the Second World War. Our on changes in the geochemistry of the water extractions had ensured a constant groundwater, all these aspects need to be downward flow towards the sea with the considered for us to maintain the production watershed. After the Sand Motor was built, of clean drinking water of high quality to the watershed shifted towards the sea, but serve the public.” part of the groundwater suddenly moved in the other direction. This meant that the What are the main findings of the pollution present in that dune suddenly NatureCoast program for you as end-user? came our way. And we had to take quick "I think it has created a large sense action to prevent our water sources from of awareness on the subject and an being contaminated. At the time, we put a understanding of the effects it has on its management and control measure in place surroundings. The program also produced to pump up water, and we still have to a groundwater model created by Sebastian maintain this measure today.” Huizer, which we were able to use on several occasions.” How do you see the role of scientific research at the Sand Motor? “After its construction, of course, there was a lot of research into the effects of the Sand Motor. Twelve PhDs conducted all kinds of research into the effects on nature, ecology, hydrology, geochemistry and more. However, I wonder how much research had actually been done on these effects before the Sand Motor was built. If these effects had been known ahead of time, I doubt that the project would have been executed in the same way. Of course this is inherent to a pilot project. The scientific research has given us more insight into the effects of large sand nourishments and this knowledge can be used in future large sand nourishments along the coast.” – INTEGRATION OF RESEARCH SIX

154 155 SEVEN | OPPORTUNITIES FOR SANDY STRATEGIES – OPPORTUNITIES FOR SANDY STRATEGIES SEVEN

156 157 Figure 1. Arjen Luijendijk Global Opportunities (Image by JAM Visual Thinking) EXPLORING THE POTENTIAL

INTRODUCTION

This chapter looks at the international To conclude the chapter, the principle potential of sandy solutions to mitigate investigator will reflect on the global coastal erosion and maintain or develop potential for large-scale sandy solutions to various functions of the coastal ecosystem. perform additional functions beyond coastal First, we discuss the evolution of safety (Page 176). nourishment strategies in the Netherlands since the 1980s. We pay special attention to how adapting to climate change will affect future nourishment needs. Next, we will outline the sandy solutions that have been implemented along the Dutch coast in the past and recently. We will illustrate the most recent trends in sandy solutions that have adopted the Building with Nature concept along the Dutch coast and lakes: Hondsbossche Duinen, Prins Hendrik Zanddijk and the Houtribdijk.

During the NatureCoast project many delegations from across the world visited the Sand Motor. A common question that many visitors asked the NatureCoast researchers was: "Could this also be built at our coast?" This was often followed by extensive discussions to understand the reasoning behind the question. In several cases that led to the active involvement of NatureCoast postdocs in the planning and design of a project. In this chapter we will highlight our experiences and findings from four cases: Bacton, United Kingdom (Page 166), Scania, Sweden (Page 168), Negril, Jamaica (Page 170), and Lima, Peru (Page 172).

In addition to responding to these queries, we have developed methods that can follow all the beaches in the world and their

shoreline behavior over the last 33 years. – OPPORTUNITIES FOR SANDY STRATEGIES We used satellite imagery to detect the locations of sandy beaches and identify

their shoreline position for every year since SEVEN 1984. This resulted in a database of all 158 (erosive) sandy beaches across the globe. 159 Figure 1. Arjen Luijendijk and Jaap van Thiel de Vries Alternative nourishment designs: water in the cross-shore direction and a Traditional beach and dune nourishments, gradually create a wider coastal defense frequently used from the 1970s onward, over time. SANDY STRATEGIES place sand directly on the beach and dunes. c Concentrated mega-nourishments exploit b Shoreface nourishments, initiated in the both marine and aeolian processes to 1990s, use natural marine processes to redistribute the sand both crossshore and redistribute the sand that is placed under alongshore.

Working with sand Despite the limited lifetime of nourishments, and much more acceptable to the public. 31% of the world’s coastline is composed sandy strategies seem to be gaining Consequently, shoreface nourishments of sandy beaches with dunes. These in popularity, for two reasons. First, have been widely applied along the Dutch dunes form a natural defense protecting nourishments allow for adaptive coast since the late 1990s (Figure 1b). Such the hinterland from flooding, while at management to changing conditions and a nourishment typically consists of about the same time providing valuable space unexpected circumstances. This flexibility one to two million m3 of sand and has a for recreational activities and nature means that costly maintenance can often lifetime of about three to five years. These development. Due to alongshore variation be postponed, which can make sandy nourishments are generally cheaper for the in hydraulic loads, sandy shorelines can strategies more competitive than hard same volume (costing about 50% less) and experience structural sand losses, which alternatives. Second, there is an increasing use natural marine processes in the surf results in a receding coastline over the demand for measures that integrate zone, which transport the sand towards the longer term. This can negatively influence multiple functions (coastal safety, economy coast allowing the beach to widen over time. the functions in the surrounding areas. To and nature) at once, which a smart sandy a Traditional beach and dune nourishment mitigate these effects, coastal managers strategy can achieve. At present, most beach nourishments in the implement various measures, either hard Netherlands are implemented as shoreface constructions (i.e., a sea wall or revetment) Dutch nourishment strategies nourishments. However, this practice has or soft (sandy) sediment strategies involving The Dutch coastal zone, like many other low- a few disadvantages. Every nourishment periodic sand nourishments. lying coasts, has been subject to persistent buries part of the marine ecosystem erosion over the last centuries. To reduce (Chapter 5), and it takes several years for the Sandy strategies are usually achieved the risk of flooding, coastal structures were system to recover. Consequently, five-yearly through sand nourishments, whose design built from the 1700s onward, strengthening nourishments tend to leave the ecosystem (shape, volume, frequency) typically depend the coastline locally with seawalls, in a continuously disturbed state. Moreover, on local demands and on the nearby breakwaters, and wooden or rubble-mound nourishing only the upper part of the availability of sand with the desired grain groins. However, these structures proved shoreface tends to lead to over-steepening size and color, as well as the availability of not always to be sustainable and effective. of the coastal profile, which causes more equipment to mine the sand. Globally, beach A more fruitful way of mitigating erosion offshore-directed sediment transport, and dune nourishments are by far the most was introduced more recently (in the making it necessary to nourish ever more common strategy, with sand placed directly 1950s) by using sand nourishments. After frequently in the long run. The Sand Motor b Shoreface nourishment on the beach and dunes. the success of initial nourishment projects, introduced the concept of concentrated it became government policy to preserve mega-nourishments (Figure 1c), where both Sandy shores constantly reshape their the Dutch coastline at its 1990 position at marine and aeolian processes are used to active profile in response to the actual all costs, with sand nourishments as the redistribute the sand both cross-shore and hydraulic conditions and efficiently primary tool. alongshore. This approach gives the marine dissipate the incoming wave loads. A sandy ecosystem ample time to recover, since no coastline tends to rotate perpendicular to Since then, sand nourishments have been new nourishments are expected in the next the incoming wave angle in the longshore applied successfully in the Netherlands twenty to thirty years. direction, which may result in consistent to mitigate coastal recession. Initially, local sand losses over a longer period. nourishments were implemented as beach Trends in Dutch sandy strategies

Sand nourishments are typically employed and dune nourishments, with sand placed An alternative type of concentrated – OPPORTUNITIES FOR SANDY STRATEGIES to replenish these persistent losses, but directly on the beach and dunes (Figure 1a). nourishment was introduced in 2018: delta they do not address the cause of erosion However, theoretical and field-based nourishment in a tidal inlet system. A sand 3

and their effect will thus have a limited studies showed that placing the sand on volume of 5 million m was placed at the SEVEN lifetime depending on volume and local the foreshore can be effective as well, is outer delta of the tidal inlet of Ameland as 160 c Localized mega nourishment erosion rate. cheaper, less intrusive to beach amenities, a pilot. The marine processes will spread 161 Figure 2. the sand in the system to adjacent beaches The three-kilometer long Prins Hendrikdijk Spatial and temporal 15 to feed these with sand. By shifting on the Wadden Sea island of Texel also no scales for Dutch "Mega" the nourishment location, (part of) the longer meets the safety requirements and nourishments. nourishment nourished sand can also be used to i.e., feed is undergoing unique, natural reinforcement (Figure by the Wadden Sea to let it grow with sea-level with sand. A diverse sandy area will be Quirijn Lodder, Ebb delta/ rise. The trend in coastal management at constructed in front of the current dike Rijkswaterstaat) 10 Tidal channel Rijkswaterstaat over the last 30 to 40 years (Figure 3b). The innovative improvement has been towards nourishments with longer method, involving a flexible design that lifetimes and which indirectly feed larger accommodates future sea-level rises and areas. Since 1990, annual nourishment enhances natural values in the Wadden Sea, Shoreface volumes have increased to about 12 million will keep flood risk management up to par. m3 per year for the entire Dutch coast (as The purpose of the vegetation is to reduce

Spatial (km) 0 of 2018). This annual nourishment volume the nuisance of wind-blown sand and will increase as we are forced to cope with stimulate new dune development. Figure 3. sea-level rise. Recent estimates for the a Hondsbossche Dutch coast show that annual nourishment Finally, the sandy foreshore solution in the Duinen (below left; Beach volume will need to increase by a factor pilot Houtribdijk aims to dissipate incoming photo courtesy 0 of 3-4 (for a 0.4 m sea-level rise), up to waves during storms before these waves can HWBP) a factor of 20 (for a 2 m sea-level rise in reach the dike behind, thereby enhancing b Prins Hendrik 2100). This represents tens of millions m3 safety against flooding, while creating a new Zanddijk (below 0 5 10 20 30 per year, in the worst case well above muddy habitat at the same time. Several right; impression by 200 million m3 per year. vegetation types (willows, reed, herbs) and HHNK) Lifetime (years) various initial soil conditions have been c Houtribdijk (far Another clear trend is that “engineering assessed as effective methods to establish lower right; photo with vegetation” is becoming a more vegetation (Figure 3c). The purpose of the courtesy Ecoshape) important aspect in designing successful vegetation was to stabilize the sand in front sandy strategies. This is first because of the dike to guarantee a certain amount vegetation can help stabilize a sand sand volume in front of the dike for coastal body at a specific location. In addition, safety. planting vegetation can influence how the landscape evolves (i.e., by stimulating dune formation). We would like to end this chapter by introducing three recent projects that incorporate vegetation into the design of the sandy solution, as can be seen on Figure 3. They differ in size, shape and application and represent the latest components of the Sandy Strategies and Building with Nature family.

The Hondsbossche & Pettemer Zeewering no longer met current safety standards (Chapter 2). Therefore, the dike was reinforced in 2015 with a soft, natural barrier of 30 million m3 of sand on the seaside of the dike (Figure 3a). The design consists of a soft shallow foreshore (the beach), with various dune habitats. These

connected systems make up the primary – OPPORTUNITIES FOR SANDY STRATEGIES flood defense and provide the demanded spatial quality. The initial topography in

combination with vegetation creates the SEVEN starting conditions for landscape evolution 162 for nature and recreational objectives. 163 Figure 1. Arjen Luijendijk and Alexander van Oudenhoven Global interest in the mega-nourishment concept. Locations indicated in green circles have been actively studied and presented in EXPLORING OTHER SANDY SHORES this book. (Negril photo courtesy Couples Resort; Lima photo by Christian Córdova) INTRODUCTION TO INTERNATIONAL CASES

The Sand Motor has attracted attention Unlike in case of the pilot Sand Motor, there for a successful project. It also shows that from inside the Netherlands and from far was too much at stake in each of these most policy actors are at least as interested outside. As described on Page 138, hundreds cases for anything to turn out differently in short-term solutions as they are in longer of international delegations have visited the than expected. The perceived uncertainty term ones. Sand Motor since 2011, to learn more about made it challenging, albeit not impossible, its workings and to see it for themselves. In to establish a partnership or consortium to The Sand Motor cannot be copied blindly addition, several organizations and policy tackle the coastal erosion problem in each of With sufficient knowledge of the physical actors have approached the NatureCoast these cases. and governance system at hand, the research team with specific questions about concepts of Building with Nature and Bacton Beach, UK Scania Beach, Sweden their own local coastal erosion problems. Agreement needed on problems and sandy solutions can work elsewhere. The four cases that will be described in solutions Most of our contacts were enthusiastic the following pages, from Bacton (United A gas terminal, holiday residences, a about the possible solutions presented Kingdom), Scania (Sweden), Negril tourism hotspot, and the capital of Peru: by NatureCoast. In the Bacton case, (Jamaica) and Lima (Peru), could not be the stakes seem obvious and sufficiently our involvement even extended into the more different from each other. Not only is high that everyone should to care. However, design phase and Environmental Impact the morphology different, but the political collaboration between public, private and Assessment study. In 2019, a solution based climate, main economic activities and the local stakeholders often developed slowly on the feeder concept of the Sand Motor will actual importance of sandy beaches differs and poorly. What caused this? Often, be constructed at the Bacton Terminal. in each case. However, representatives from the stakeholders who expressed their each of these locations contacted us about concerns first were not the actual decision We learned that the Dutch Sand Motor their eroding sandy beaches, to learn from makers. They were inspiring pioneers, should not be copy-pasted to other coastal our experiences, and to see if a solution like rather, with a hunger for innovation and an sites around the world, as the solution the Sand Motor, with the same underlying impressive knowledge of the local system. depends on the governance, societal and principles, would work in their case. In However, there was often no consensus physical context. In many regions in the the following pages, we will describe the about the key problem, as well as about world, sand might simply be too costly key challenge for each case, characterize the potential solutions. This resulted in to mine, so coastal erosion will require the physical conditions and the local misinformation, miscommunication and different solutions than beach nourishment. governance system, and look into possible mistrust. If issues like coastal erosion, and When we were invited, we shared our ways forward. But first, we will highlight even climate change, are not on the radar experiences with the Sand Motor and some overall observations and lessons of key stakeholders, the search for solutions the NatureCoast program, but we always Negril Beach, Jamaica Lima Beach, Peru learnt. becomes difficult. proposed site-specific solutions, inspired by multifunctional, interdisciplinary thinking. Driven by curiosity and desire to be On top of that, the fate of an innovative With a broad consensus on the underlying innovative solution always depends on the volatile and problems and an inspirational leader and In all cases, we were contacted by highly unpredictable context of decision motivator, you end up with a “perfect stakeholders who were not afraid to be making. Decisions can be overturned in storm” leading towards inspiring new sandy different, to stray from the usual path. a heartbeat, funding and support can solutions. Hard engineering was generally regarded disappear just like that. Sudden events,

as not cost-effective and/or unattractive such as unexpected election results can – OPPORTUNITIES FOR SANDY STRATEGIES from a tourism and ecological point of change plans overnight (as was the case view. Thus, innovation was an important in Lima). Although this unpredictability

driver for the stakeholders’ interest in our seems unavoidable, it is fair to say that a SEVEN work. We quickly discovered, however, that thorough understanding of the political and 164 innovation should not equal experimenting. governance issues at hand is instrumental 165 Figure 1 (left). Arjen Luijendijk and Vera Vikolainen The cliff coast at Bacton Terminal showing small-scale SANDSCAPING INSPIRED BY THE SAND MOTOR protection works. (Photo by Royal HaskoningDHV) INTERNATIONAL CASE: BACTON, UNITED KINGDOM Figure 2 (right). Cliff erosion threatening The challenge allow the terminal to continue operating is regional. Therefore, an overarching residences. (Photo Coastal management in Europe is shifting into the future. Due to its nature-friendly coordinated approach would not be realistic by Maurice Gray) toward soft coastal protection strategies and green nature, Sandscaping created a in the British context, although it might to deal with flood risk and erosion. An great opportunity for Bacton Terminal and make things easier. The Bacton case shows interesting example of this transition is neighbouring villages to collaborate. that flexibility is essential when complex the coastal enforcement project for the and dynamic governance situations make a Bacton Gas Terminal (operated by Shell In 2017 it was decided that the coastal fully planned development risky and a more and Perenco) at Bacton, North Norfolk. The enforcement would be based on the adaptive management style inevitable. Here, terminal is threatened by cliff erosion, and long-term solution of Sandscaping. Royal all the project partners worked together and “Sandscaping” was included as an option HaskoningDHV was appointed to design the the private actors play an active role; both to protect the terminal and nearby villages solution whereby over 1.5 million m3 of sand civil service and ministerial levels have been Figure 3. from coastal erosion. In this initiative, with will be placed along the coast to protect involved in the case, and different funding The four stages Sandscaping being akin to “Building with a 5 km coastal stretch including the terminal sources have been combined, with a flexible of the Bacton Nature”, British partners collaborated to and its neighbouring communities. The division of responsibilities. nourishment: translate the Dutch Sand Motor to the solution will enhance the natural coastline present situation, different physical and socio-political context without leaving a permanent mark and The Bacton case clearly illustrates that construction of the of the UK. Royal HaskoningDHV, one of the can also be easily adapted and extended if many aspects of the pilot Sand Motor and nourishment, and partners in the Sandscaping initiative, was needed in the future. The Bacton solution NatureCoast can serve as valuable input and the situation after responsible for the design of the long- is a great example of a design that provides inspiration to sand replenishment projects 5 and 20 years. term sandy solution. Jaap Flikweert, Flood multiple functions and generates benefits elsewhere. (Figures by Royal Resilience Leading Professional at Royal for different stakeholders while also HaskoningDHV) HaskoningDHV, invited the postdocs of receiving multi-party funding. NatureCoast to share the latest findings of the Sand Motor during the design The way forward phase of the Bacton coastal enforcement. The nourishment is scheduled to be Besides the technical challenges of making constructed in 2019, after which a accurate morphological forecasts of the multidisciplinary monitoring program sandy solution, the main challenge lay in will observe its evolution in detail. During establishing the public-private venture of design sessions in the UK, we shared our Bacton Gas Terminal and the North Norfolk ideas on the dispersive behavior of the District Council. sand, the aeolian transports to be expected after construction, and the relevance of The system the sediment composition. In addition, Long-term coastal erosion is depleting the the interdisciplinary NatureCoast project beaches of North Norfolk, leaving cliffs inspired those involved with the Bacton re- and seawalls exposed. Severe storms in enforcement to also develop a knowledge 2007 and 2013 caused significant cliff program around the project. erosion and flooding along the coast of East

Anglia, underlining the project's urgency. Our research on governance in the UK – OPPORTUNITIES FOR SANDY STRATEGIES The Bacton Gas Terminal is an important showed that the context in England is energy asset for the UK as it provides about generally restrictive for coastal innovations

a third of the UK's gas supply. To protect like Sandscaping. In the UK, coastal SEVEN the terminal and the associated pipelines, a protection is simply not an issue of national 166 sustainable solution was preferred that will importance, and the scale of the issues 167 Alexander van Oudenhoven and Lotte Bontje GETTING LOCAL BEACH EROSION ONTO THE NATIONAL AGENDA INTERNATIONAL CASE: YSTAD, SWEDEN

The challenge Not content with the outcomes, Ystad was The way forward Only 3% of the Swedish coastline is the first Swedish municipality to start a As we saw in Chapter 2, the pilot Sand Motor composed of sandy beaches. However, in beach nourishment. The proposed project demonstrated that policy change is more Scania county in southern Sweden, sandy would supply sand at multiple locations likely to occur when involved actors are beaches form around 25% of the coastline. using 340,000 m3 of sand in total. Although convinced that there is a problem and that During the past decades, erosion has been the nourishment permit was received something needs to be done about it. The observed at several places along Scania’s in 2001, the permit for offshore sand Ystad authorities are continuously searching coast. Especially the Ystad municipality extraction was rejected several times. Only for such policy windows. In this case, there is in Scania has suffered (Figure 1). Beach ten years later could the first two beach currently no consensus that coastal erosion erosion in Ystad affects both public and nourishments take place, followed by constitutes a problem for which structural private properties, including more than 1000 another round in 2014 (Figure 3). policy changes are necessary. In addition, summer holiday residences along the coast. not everyone is convinced that beach This delay was the result of a complex nourishments are the go-to solution. Even though the Ystad municipality requires decision-making process, different support, licenses and approval from priorities at different levels, and several One sign that this status quo has changed national authorities, it is responsible for perceived uncertainties. First, Ystad had somewhat was the appointment of a national Figure 1 (top left). maintaining its own public infrastructure. to apply for two different permits from erosion coordinator in 2003. This authority Coastal erosion in Coastal erosion, and potential solutions two different national authorities, one focused mainly on sharing knowledge and Ystad. to tackle it, remains the responsibility of assessing the environmental impact of creating awareness of the coastal erosion the municipality. However, getting the the nourishments, the other evaluating problem and the potential solutions, such as Figure 2. (top right). local problem of coastal erosion, and the the impact of sand extraction. On top beach nourishment. This awareness raising Example of a hard related need for beach nourishment onto of that, a regional administrative body, could prove useful, particularly in view of the coastal protection the national policy agenda has proven representing the government, formally negative effects hard solutions have had on structure at the challenging. Armed with the lessons learnt has to approve all spatial plans of the coastal erosion in the Ystad area. coast of Löderup, from the pilot Sand Motor (Chapter 2), municipality and check that they correspond in 2015. Hard governance researchers of the NatureCoast to national interests. Frustratingly, although Another solution could lie in connecting engineering program set out to identify why beach the regional authorities have always coastal erosion with a more widely accepted solutions are still nourishment had not been embraced by acknowledged that coastal erosion is a problem, namely climate change. This widely favored national decision makers. local threat, they also acknowledge that might lead to changes in administrative in Sweden, due their agenda is determined by the national and planning systems and, hence, open to perceived The system government. NatureCoast researchers new policy windows. Perceptions of beach uncertainties related Many coastal erosion interventions were observed that, just like in the UK (Page 168), nourishment as a solution might also to soft engineering. implemented in Ystad between the 1950s beach erosion in Sweden is not generally change, as more and more monitoring and 2000. However, these hard solutions, perceived as problematic on the national results from beach nourishment projects Figure 3. (right) such as breakwaters, groins, and revetments level, but rather as a naturally occurring throughout Europe are published. In 2021, The nourished beach have proven largely ineffective and in phenomenon. In addition, people involved the current beach nourishment licenses will with the still visible many cases have even made the situation with granting permits were concerned end. If Ystad intends to continue with beach groins at Ystad worse (Figure 2). Houses could be seen about the environmental impacts of beach nourishments, it will have to apply for new

Sandskog, in 2015. falling into the sea in the 1970s, and the nourishments and the continued availability licenses and, as a result, will have to reopen – OPPORTUNITIES FOR SANDY STRATEGIES groins could not prevent further erosion. of sand resources. The researchers the discussion on coastal erosion and beach All photos by Lotte Local revetments could sometimes save concluded that the diverse perceptions of nourishments. Perhaps, by then coastal

Bontje. houses from erosion in the short term, but uncertainties and the communication about erosion will have made it onto the national SEVEN also resulted in new and larger long-term these uncertainties were underlying causes policy agenda and beach nourishments will 168 problems. of the delay in granting the permits. become a more mainstream solution. 169 Alexander van Oudenhoven and Arjen Luijendijk PARADISE DIVIDED OVER A SEAWALL

INTERNATIONAL CASE: NEGRIL, JAMAICA

The challenge The main problem in Negril is not that the The way forward Negril is among Jamaica’s most popular beaches erode, but rather that, in recent During our visits in 2014 and 2016, it tourist destinations. Its many high-end decades, the sand simply has not returned became clear that both short-term fixes hotels together receive about 20% of all the after a storm. and a longer term solution were needed. nation’s tourists. For decades, Negril has Areas directly threatened by erosion would maintained the image of a laid-back and To understand why, take another look at have to be strengthened through targeted natural beach resort (Figure 1). However, the aerial picture. The newly constructed beach nourishments, because otherwise it is estimated that up to a meter of its road separates a swampy wetland on the surrounding hotels would lose their beautiful coastline has disappeared annually right from a coastal forest on the left. appeal. However, we stressed the need for since the 1990s. In 2012, the opportunity Moving into the seaward, the white sands continuous monitoring, which will provide arose for Jamaica’s government to tackle are covered by seagrass and beyond, the insight into beach morphology and sand the coastal erosion problem. Almost darker colors are the coral reefs. This beach transport, especially after storm erosion. 10 million dollars became available through would flood regularly, but the wetlands a climate change adaptation fund, to be would buffer the storm water and then On the long term, the Negril ecosystem spent on coastal infrastructure. The funding desalinize the soil. Though the beach would should be allowed to function again, with would be spent on a submerged breakwater erode, the seagrass and coral reef would help from its inhabitants. The wetlands that would shield the coastline against prevent the sand from leaving the system. have to be restored, and water sanitation incoming wave energy. As a result, the beach would recover during infrastructure will have to be improved calmer periods. considerably. All buildings beyond the high This decision resulted in a public outcry water line are a threat to the coastline, as is (Figure 2). Various stakeholders, including Very little of this ecosystem has remained the regular removal of seagrass. However, hotel owners, local fishermen and NGOs intact. The wetlands are being drained the most important role will have to be Figure 1. (above) Tourists enjoying another feared that this hard structure would on a large scale and are heavily polluted. played by the coral reefs. They will have to carefree day in Negril, Jamaica. impact both tourism and the environment Hotel construction and expansion is be strengthened and restored, so that they negatively. Moreover, the stakeholders continuing, and their swimming pools and can regain their role as wave breakers, fish Figure 2. (top right) Stickers with a slogan felt that they had not been consulted terraces are constructed beyond the high nurseries, and natural structures to trap opposed to the breakwater plan in Negril. adequately. In 2014, the Negril Chamber of water line. The beach has nowhere to go, the sand—and of course serve as the basis Many local stakeholders felt that they had Commerce contacted NatureCoast with the certainly not inland. To make it worse, for ecotourism. not been heard in the breakwater plan and question whether a more nature-friendly most of the seagrass is being removed feared it would have negative impacts on option might be available for Negril, based by hotel owners, allegedly because of its A wide range of solutions is available, and both tourism and the environment. on lessons learnt from the Sand Motor. nuisance to swimmers. Over half of the concerned stakeholders managed to halt coral reefs are also heavily degraded, due the construction of a breakwater for now. Figure 3. (far right) Negril just after the The system to dynamite fishing in the past and current The time had come to think about other construction of the coastal road, in 1972. Prior to our visit in 2016, the beach had water pollution, overfishing and trampling approaches. We know from the pilot Sand actually recovered slightly, due to a lack of by tourists. Many local stakeholders Motor how important stakeholders inclusion Figure 4. (bottom right) The one location severe storms in recent years. Long-term remember the old days and how the coastal and agreement is. They should agree on on Negril’s beach where the coastline is not residents of Negril knew, however, that ecosystem used to be in balance, a glimpse both the problems as well as the potential visibly eroded. The building behind this lush one severe storm would all but vanish the of which is still visible at one location in solutions and desired functions of the

vegetation was constructed well beyond beach. Especially in these hurricane-prone Negril (Figure 4). It is understandable that beach. Negril’s beach is running out of sand, – OPPORTUNITIES FOR SANDY STRATEGIES the high water line, thus giving the beach Caribbean regions, erosion is a naturally the stakeholders reacted so passionately to and its people are running out of patience. ecosystem opportunity to be its flexible self. occurring phenomenon; beaches erode not being heard. The knowledge, concern To date, in early 2019, the situation in Negril

and then slowly accrete. Negril’s beach has and involvement of local stakeholders is has remained unchanged, with the risks SEVEN Photos 1, 2 and 4 by Alexander van never been very wide; as can be seen from crucial to the future of Negril’s coastline still imminent. 170 Oudenhoven; Photo 3 by Robin Farquharson. the aerial picture taken in 1972 (Figure 3). and its economy. 171 Figure 1. Arjen Luijendijk Artist impression of two Sand Motors at the Costa Verde in Lima, Peru (created by Nahuel Beccan Davila and Adrian Puentes of FINDING COMMON GROUND FOR A “MOTOR DE ARENA” Beccan Davila Urbanismo).

INTERNATIONAL CASE: LIMA, PERU

The challenge The narrow beaches of Costa Verde are a Sand Motor. In addition to this, societal We were approached by MAP Office, currently squeezed between the ocean and goals should be considered to frame the an urban planning bureau based in the the cliff. The cliff is unstable and eroding, Sand Motor in the local context. During our Netherlands and Mexico, who were as it is made up of soft river deposits, and study we identified the following societal involvement with the Masterplan “Costa because of the pressure from on-going goals: tourism and recreation development, Verde” (Green Coast) for Lima, the capital construction atop the cliff. At the same time, aesthetics (attractive landscape with the of Peru. The artist impressions they there is increased coastal erosion from the ocean), environmental sustainability, and developed included two Sand Motors with ocean as well as the risk of tsunamis. The harmonious development. The Sand Motor’s the idea of creating a flourishing beach current infrastructure to protect the coast harmonious design with nature and benefits area in front of the cliffs of Miraflores. from the ocean is deemed insufficient. for environment could be emphasized The postdocs of NatureCoast were asked alongside its coastal protection benefits. to think about the physical feasibility of A large volume of suitable sand is required the proposed large-scale nourishment. for a large-scale nourishment. Sand from the These findings and suggestions were We presented our findings during a well- relatively nearby desert is not suitable, as presented and discussed with the Costa attended stakeholder workshop organized the properties of this sand differ significantly Verde organization office at the time. In the by the office of the mayor of Lima. from that of marine sand. The availability months thereafter, the focus shifted almost of sand at the sea bed is, however, largely entirely to elections for a new mayor of It turned out that the policy goals focused unknown. Some reports and data show that Lima, and all ongoing initiatives, including more on urban development, aesthetics sandy layers are present offshore up to at the Costa Verde Masterplan, were put and adequate infrastructure than on coastal least 15 m water depths, but they probably on hold. protection. The problem in this case was would not provide sufficient sand volume to the lack of cooperation between the district construct a large nourishment. It should be noted that this case description municipalities, the Costa Verde project is based on our interpretation of reports organization, and the other stakeholders Except for the law protecting the surf waves and data, and only one workshop and a along the coast. In addition, the legal and (Ley de Rompientes), there were no legal few meetings in Lima; it can only be seen institutional framework turned out to be limitations for the Sand Motor. Furthermore, as reporting our own viewpoint. The Lima fragmented at the national level. the authorities expressed willingness to case has taught us that a large-scale, include a Sand Motor type of solution in the dynamic, multifunctional solution offers The system Costa Verde Master plan. many opportunities for uniting a group of Costa Verde is a coastal stretch of about stakeholders with a variety of perspectives. 20 km divided into 6 district municipalities. The way forward The active involvement of stakeholders from Among other problems, Costa Verde faces The Sand Motor concept is meant to serve the initiation phase is paramount to ensure environmental degradation of the coast, multiple societal goals, with a variety of that all voices are heard. lack of spatial organization and quality, functions including costal safety, nature, and and issues related to coastal safety. To recreation. As occurred in the Netherlands, date, land along the coast of Costa Verde we believe the concept of a multifunctional has been reclaimed from the ocean using coastal solution can unite the various parties rocks and the construction remains from involved here. The goals of the district

demolished buildings. As a result, the municipalities, the Costa Verde organization – OPPORTUNITIES FOR SANDY STRATEGIES coast is unappealing and polluted. From an and other stakeholders should first be environmental and aesthetic perspective, analyzed to find common ground and define

a sandy beach would be more attractive individual goals. These goals can then be SEVEN than the current stony beach. incorporated into the conceptual design of 172 173 Arjen Luijendijk A GLOBAL VIEW ON BEACH EROSION

Coastal zones have long attracted humans and aesthetics they offer, but erosion of only continents with net erosion (−0.20 m/yr and human activities, due to the economic these coasts over the last few decades and −0.07 m/yr, respectively), with all opportunities they offer, their aesthetic is already causing coastal “squeeze.” The other continents showing net accretion. value, and the diverse ecosystem services impact of climate change on these coasts The main causes of this accretion are land they provide. As a result, coastal zones will only exacerbate this situation. reclamations, natural sediment supply by throughout the world have become heavily rivers, and nourishment strategies. For populated and developed, with 15 of Despite the utility and economic benefits example, the country-mean change rate for the world’s 20 megacities (population that coasts provide, no reliable global- the Netherlands is 2.8 m/yr since 1984. >10 million) being in the coastal zone. The scale assessment of historical shoreline global coastline is spatially varied and trends is available. Using freely available The database is publicly available comprises different coastal landforms, such optical satellite images captured since at shorelinemonitor.deltares.nl. The as barrier islands, sea cliffs, sandy coasts, 1984, in conjunction with sophisticated Shorelinemonitor tool can assist in tidal flats, and river deltas. Of these different image interrogation and analysis methods, understanding the coastal dynamics over coastline types, the sandy coasts are highly we conducted a global-scale assessment the last 33 years for every beach in the dynamic in time and space and constitute of the presence of sandy beaches and world. This database allowed us to identify a substantial part of the world’s coastline. the rates of shoreline change at those the coastal stretches that are eroding Sandy coasts are highly developed and locations. Applying pixel-based supervised around the world (i.e., erosion hot spots). densely populated due to the amenities classification, we found that 31% of the A hotspot is defined as a coastal section of world’s ice-free shoreline is sandy. Africa has at least 5 km of sandy shoreline where all the highest percentage of sandy beaches considered transects showed erosion larger (66%), while in Europe only 23% of the than 0.5 m/yr over the 33-year data set. shoreline is sandy (Figure 1). The numerous hotspots shown in Figure 2 illustrate that erosion affects large sandy Applying an automated shoreline detection beach sections around the globe. Combining method to the sandy shorelines that were this data with the information on urban Figure 1. (top left) identified resulted in a global dataset of development, derived from nightly satellite Global distribution of sandy shorelines; the shoreline change rates for the period images, we can identify the hotspots for coloured dots along the world’s shoreline 1984 - 2016. Analysis of the satellite-derived coastal “squeeze.” These are areas that represent the local percentage of sandy shoreline data indicates that 24% of the may need coastal protection measures to shorelines (yellow is sand, dark brown is world’s sandy beaches are eroding at rates mitigate coastal erosion in urban areas, non-sand). The subplots present the relative exceeding 0.5 m/yr, while 28% are growing, either now or in the future. Investigating the occurrence of sandy shorelines per degree and 48% are stable. About 18% of the sandy feasibility of sandy strategies in these areas latitude and longitude. The underlined beaches are experiencing erosion rates would be very valuable. percentages indicate the percentages of exceeding 1 m/yr. sandy shorelines averaged per continent. In addition to encouraging nourishment More severe erosion rates are found at to mitigate coastal erosion, we should Figure 2. (bottom left) various locations across the globe. About investigate ways to optimize existing Global hotspots of beach erosion and 7% of the world’s sandy beaches experience nourishment strategies, or even consider

accretion; the red (green) circles indicate erosion rates classified as severe (i.e., more constructing artificial beaches on non-sandy – OPPORTUNITIES FOR SANDY STRATEGIES erosion (accretion) for the four relevant than 3 m/yr). Erosion rates exceed 5 m/yr coasts. Any such assessment or proposal shoreline dynamic classifications (see along 4% of the sandy shoreline and are will need to start with a comprehensive

legend). The numbers presented in the main greater than 10 m/yr for 2% of the global understanding of the physical conditions SEVEN plot represent the average change rate for all sandy shoreline. From a continental and the ecosystem, as well as the 174 sandy shorelines per continent. perspective, Australia and Africa are the governance setting. 175 Marc Bierkens and Gu Oude Essink OPPORTUNITIES FOR FRESH GROUNDWATER RESOURCES IN A MEGA-NOURISHMENT REFLECTION

Marc Bierkens is a professor of Hydrology at Utrecht University and These are interesting preliminary estimates, but reality is a bit senior researcher at Deltares; Gu Oude Essink is a senior researcher more complex. Fresh groundwater will not only collect in the Sand at Deltares and a (part-time) associate professor at Utrecht Motor itself. Even after it has been completely dispersed along the University. Both worked on project S5, which focused on studying shore, the wider beaches and dunes that result from the project will fresh groundwater resources and the soil quality of the Sand Motor. increase fresh groundwater storage in the neighboring dune systems as well. Since the morphology of the Sand Motor will drastically change over its lifetime, the relative storage of groundwater in the The Sand Motor was originally thought of as a bold and innovative sand body and the connected dune system will also be affected. mega-size sand nourishment for eroding sandy coastlines. It was As a matter of fact, fresh groundwater dynamics under changing expected to take advantage of the protective abilities of beaches morphology have hardly been studied before. Finally, apart from a and dunes, but unlike traditional linear beach nourishments, the slowly changing morphology, the fresh groundwater system inside disturbance to ecosystems would be concentrated while creating the Sand Motor will be subject to tides and storm surges. How will opportunities for new ecosystems to develop. However, the coastal these affect the volume of fresh groundwater stored? scientists who set out the NatureCoast research program, had the visionary idea that a large body of sand would also collect Our project set out to study this complex system by combining fresh groundwater, which would represent an additional benefit of groundwater level and salinity observations on the Sand Motor and concentrated mega-nourishments. neighboring dunes with detailed electromagnetic measurements of salinity over many tidal cycles and during storms. These data As the Sand Motor was a completely new phenomenon in coastal were used together with regional-scale high-resolution salt-fresh protection, there were no studies available on how such a structure groundwater models to assess the past and future development would affect the development of fresh groundwater. However, of fresh groundwater resources in the Sand Monitor and its based on the understanding of the dynamics of fresh groundwater surroundings. Based on this, we expect a total 10 million m3 of systems in coastal environments simple estimates could be made. additional fresh groundwater to be stored through 2050. This An elevated ridge like the Sand Motor should create a groundwater is an additional 0.3 million m3 per year on average, which would table storing water above the surrounding land surface; we would be sufficient to supply drinking water to 5000 people. It should, expect the table to be higher the less permeable the subsoil and however, be noted that 90% of the volume will occur in the the wider the elevated ridge. Moreover, as fresh groundwater floats neighboring dune system, as the Sand Motor disperses, and the on saline groundwater, the depth of the fresh-salt water interface coastline expands. The Sand Motor harbors about 1-1.5 million m3 will be approximately 40 times the height of the groundwater of fresh groundwater, and this volume built up rather quickly during table. So, if we expect the groundwater table at the Sand Motor the first 5 years of the Sand Motor’s existence. to be on average 0.5 meters above mean sea level, the fresh-salt water interface would be approximately 20 meters below mean We are currently assessing the potential of mega-nourishments sea level. With an average sand porosity of 0.35, this would mean such as the Sand Motor for creating freshwater resources around a water storage of ~7 m3 water per m2. The rate at which this fresh the world. Obviously, creating a Sand Motor for the sole purpose of groundwater collects will depend on the groundwater recharge rate. fresh groundwater storage is not economically feasible. If that is the In the Netherlands, groundwater recharge in permeable sands is primary goal, there are better alternatives such as artificial recharge about 350 mm/year, which means that it would take about 20 years and aquifer storage. However, as a byproduct of coastal protection, to reach maximum water storage. this certainly has potential on sandy erosive coastlines, which

represent 17% of the global shoreline. Moreover, this approach will – OPPORTUNITIES FOR SANDY STRATEGIES depend on the type of sand (permeability), climate (recharge rates), Figure 1. (left page) the rate of coastal erosion, the frequency of storm surges, and

Satellite image (Sentinel-2) of March 12th, 2016 amplitude of tides. We estimate that about 50% of sandy erosive SEVEN showing the freshwater plume (and sediments) coastlines would be suitable for developing fresh groundwater 176 of the river Rhine entering into the North Sea. resources, particularly sites where dune systems already exist. 177 AUGUST 2016 General manager Hydronamic JAAP VAN THIEL DE VRIES – BOSKALIS

INTERVIEW

In what way is the Sand Motor unique? design something that would perform Is the knowledge resulting from the Sand "First, the Sand Motor is physically unique. equally well at a different location." Motor research relevant to Boskalis at This nourishment is larger in scale and other locations? volume than anything we have done before, How relevant is multidisciplinary research "We present many of the concepts and which makes the project groundbreaking on the Sand Motor? the philosophies behind the Sand Motor to and offers new opportunities to coastal "The Sand Motor is a solution where the our clients and we make alternative value zone planning. Its scale gives the initial conditions are created by building with propositions inspired on the Sand Motor to opportunity to shape a nourishment in a sand and water, after which the ecosystem address our client needs. In doing that, we completely different way, thus creating and people can take advantage of it. The often use the Sand Motor as a case, to zoom an interesting landscape from various interactions between the ecosystem and in on a specific location, and use it as start perspectives." people determine whether the design will point of a search to a tailor-made solution ultimately be a success. Understanding that fits the local needs. Depending on the "The Sand Motor is also unique in terms of these interactions is thus a prerequisite for client’s request, the challenge can be to involved parties and stakeholders, and the successful design." control sand movement along the coast, way in which they have worked together. but also on how you can integrate multiple It is a "Living Lab", in which many people What are the main findings of the functions in a strategy. The research findings have embraced the Sand Motor as a place NatureCoast program? from the NatureCoast program help to to recreate and work. Many natural and "First of all, the Sand Motor and the substantiate these design challenges. societal functions have developed on NatureCoast program have been established For example based on the knowledge the Sand Motor that were unforeseen, by a unique collaboration within the sector, developed, we can tell our clients how the and which resulted in various positive that can serve as a blueprint for future volume associated with a "sandy strategy" interactions between the natural system projects and initiatives. The fact that will behave at a larger scale. In a broader and people that we had not considered this collaboration works, knowing what perspective the NatureCoast program beforehand." the pitfalls are, what you have to discuss contributed substantially to the Building between partners, and what you have to with Nature innovation program. Based How do you see the role of scientific organize upfront, are very important lessons on the knowledge and design guidelines research at the Sand Motor? to shift the boundaries of knowledge and available from this program we can offer "Crucial. The Sand Motor was designed for coastal protection." extra value to our customers in many the Delfland coast and we had a certain locations around the world." idea how it would develop. Due to scientific "But it is also about hard knowledge. To research we are capable to understand protect our coast in the future against the observed developments over the the rising sea level, more sand for coastal past years by really unravelling these. nourishments will be needed. Preferably The latter is crucial, because if you were these nourishments have a longer lifespan, to apply solutions of this scale elsewhere so that we can create ecological benefits in the world, these would always behave and add social value. The Sand Motor is different than at the Delfland coast. That great example strategy of how this could be knowledge, the real understanding of what realized. The next big challenge is that we

you observe, in terms of physical processes, really embed this successful pilot strategy – OPPORTUNITIES FOR SANDY STRATEGIES ecological processes, governance in our mainstream way of working: the Sand processes and the interactions between Motor as stepping stone towards a different

these is very important if you want to approach to coastal management." SEVEN

178 179 JULY 2017 Leading Professional Flood Resilience JAAP FLIKWEERT – ROYAL HASKONING DHV

INTERVIEW

In what way is the Sand Motor unique to contribution to improve our work, especially pilot Sand Motor as a whole, everyone you as end-user? the computer modeling. I can tell our client involved seems to be content. This is “First and foremost, it offers a unique that scientific research is being conducted, certainly an indication that the project opportunity to engage in a large-scale and and that researchers involved with the Sand works, both in terms of coastal processes complex innovative experiment, one that Motor have participated, which creates a and other aspects. Of course, there were a we always hoped for. The fact that it proved sense of trust.” few hiccups, for example that the coastal possible, in the Netherlands, to spend over processes worked a little slower than 70 million euros on such an experiment How relevant is multidisciplinary research expected. To some extent, this leads to and to include all the research by the on the Sand Motor for you as end-user? confidence at the location where you place NatureCoast program and the monitoring by “That too is essential. Our clients in the it, but it also means that another location Rijkswaterstaat, gives me, as an end-user, a UK explicitly see their sand motor as elsewhere that would like to receive the sense of confidence.” a multidisciplinary and multifunctional sand, will have to wait a little longer." project. In terms of impact, but also in "It is also unique since the experiment is terms of the opportunities it could create. "NatureCoast findings, combined with probably even larger in scale than most Although I think that the technical aspect our own calculations for the project in the real-world applications of the concept in is ultimately the make-or-break factor, this UK, have influenced our design here. For other places. For example, "our sand motor" multifunctionality provides considerable instance, we might be able to promise a in the United Kingdom is a lot smaller, but added value. And the fact that there is a longer life of the sand motor at the gas the fact that "yours" has already been multidisciplinary research program out terminal. But for the villages further down constructed on such a large scale and there is extra inspiring. We would also like the road, where the sand also plays a that it appears to be working gave those to have such a program on the project, but role, we could not rely purely on natural involved here a lot of confidence. After all, it is proving more difficult to find money as processes. By considering the pros and it is unique that everyone is happy with it, compared to in the Netherlands. However, cons identified by the NatureCoast not only from a technical perspective but NatureCoast has certainly inspired us.” research, we were able to create a more also from a multifunctional perspective. dependable design.” The decision makers, the financiers and What are the main findings of the the stakeholders at our location, everyone NatureCoast program for you as end-user? Is the UK also interested in interdisciplinary actually thinks it works. I don't think I would “The technical content that we applied most research, and if so what is the reason have succeeded in realizing such a project in specifically, is the knowledge about wind- for this? the UK, if I hadn't been able to present such blown sands. Our clients wanted to know “It is generally acknowledged that an a compelling example from elsewhere to how the wind-blown sand transport would integrated approach is difficult to get done, my client.” affect the project. NatureCoast drew up but it still is something that everybody calculation rules that indicate how much wants. Everyone agrees that it is smarter How do you see the role of scientific sand is displaced by the wind. This deals to take as many factors as possible into research at the Sand Motor? with the negative effects of wind-blown account when designing a project. The fact “We had to apply our sand motor in a sand. Our sand motor project is adjacent that NatureCoast succeeded and that the different context, but the knowledge and to a gas terminal, and nobody wants too story can be told in this way, ensured that experience developed at NatureCoast much fine sand entering the system of the our client in the UK wants to cooperate in

certainly contributed to this. For example, terminal. There were no formulas to model this specific application of Building with – OPPORTUNITIES FOR SANDY STRATEGIES we were able to apply knowledge about this precisely, but the NatureCoast research Nature. We have not yet succeeded in wind-blown sand that was developed at provided us with first insights.” setting up a similar research program here,

the Sand Motor. But we also brought Arjen but the bottom-up stimulus from clients and SEVEN Luijendijk in as an external reviewer for "There are also important, more general researchers is inspiring and together we are 180 our project in the UK, and he made a real conclusions to be made. Looking at the trying to work in that direction.” 181 EIGHT | REFLECTIONS – REFLECTIONS EIGHT

182 183 Figure 1. (top left) Figure 2. (top right) Figure 3. (bottom Figure 4. (bottom Alexander van Oudenhoven and Arjen Luijendijk During one of many Simeon Moons left) Jantien Rutten right) NatureCoast PhD-days, Emily van in dialogue with explaining the sand researchers, Egmond shares her end-users at the movement of the end-users and THE MERITS OF INTERDISCIPLINARY RESEARCH design for the “Sand final NatureCoast Sand Motor during members of society Motor 2.0” based on symposium 2017. the excursion at the discussing after the the insights of her 2016 Rijkswaterstaat symposium. research. conference. NATURECOAST PERSPECTIVE

Before handing over to key experts and end-users with their third of all attendees were from academic institutes. About the same reflections on the NatureCoast program and the pilot Sand Motor, number came from private companies, followed closely by policy allow us to reflect on our own experience, from the perspective of institutes and applied research institutes. post-doctoral researchers with the task of integrating, applying and disseminating the research done by twelve PhD researchers. We will In dialogue with society do so in four steps, guided by the four pictures on the left page. Apart from end-users, NatureCoast researchers were regularly subjected to questions and requests from other members of society, Implications for design connect us all who seemed to have an almost insatiable desire to learn more about What connects twelve keen, young minds, each working at different the Sand Motor. Through dozens of excursions each year, we were institutes and on very specific topics? We always emphasized the able to spread the word about sandy solutions and scientific research potential implications and the context of the research, specifically (Figure 3). In addition, many researchers were invited to give guest for future designs of sandy solutions. Thanks to NWO-TTW, we presentations and attend discussions with numerous stakeholders, could organize numerous writing weeks, field trips, and in-depth ranging from policy administration, restaurant managers, the discussions, which made each researcher aware of the usefulness of Rotary and artist collectives. Although it demanded time and effort their own work. It also opened their eyes to other scientific disciplines from our researchers, the benefits of this dialogue with society are and ways of thinking. For example, when we asked each researcher to twofold. NatureCoast researchers became very adept at explaining design the “Sand Motor 2.0” based on their own findings (Figure 1), and communicating research in an engaging and accessible way. In we ended up with apparently wildly different ideas, which after addition, during the past five years our researchers spread the word discussing, did not seem to differ that much in the end. Unfortunately, about Building with Nature and the Sand Motor, while speaking at producing concrete outputs, such as papers and ongoing collaborations, scientific conferences, invited workshops, and while engaging with proved challenging. After such meetings, the PhD researchers foreign delegates visiting the Sand Motor on location. understandably prioritized their own project above “side-projects” related to integration. This is an inevitable consequence of organizing Integration makes it truly interdisciplinary research a research project around 12 individual PhD research projects. Throughout the book, many end-users have emphasized numerous innovative aspects of the Sand Motor and the NatureCoast project. End-users make it “real” We would argue that one of the most important innovations of Regular and in-depth interaction with end-users was a fundamental NatureCoast is the fact that a separate work package and, thus, part of the NatureCoast program. The end-users made the research resources were allocated for integration, both within and between “real”, by offering practical knowledge and raising valuable questions work packages. This integration had the overarching goal of to better understand the the Sand Motor's behavior. During these connecting research to end-users and society at large, as well biannual end-user meetings, our researchers pitched their latest as exploring the opportunities for using the new knowledge to findings to all, before sharing more detailed findings and questions contribute to sandy solutions elsewhere in the world. Although this with end-users involved in that particular research topic. Although approach presented us with challenges, and we might at times have these meetings were usually attended by between 50 and 80 people, demanded too much from the researchers and their supervisors, it has it proved challenging to mobilize an equal number of end-users been rewarding to work in such a pleasant and truly interdisciplinary for each research topic, which sometimes disappointed the PhD setting. However, in many ways we have only just begun working researchers. However, many successful collaborations did result together. Many scientific papers are still being written and published, in co-authored scientific papers and guest presentations at the and the PhD researchers are just starting off on their new careers.

end-users’ institutes. Moreover, the interaction has made the PhD The NatureCoast program has created a group of truly special people, – REFLECTIONS researchers more aware of the implications of their research. It also or, as was stated during the final symposium (Figure 4), “a unique provided them with an excellent opportunity to present themselves ‘breed’ of researchers". Researchers who always went the extra mile,

to their potential future work field. The final symposium (Figure 2), with a great affinity for working with end-users and other scientific EIGHT which was held in the summer of 2017, was attended by over disciplines, and who always looked for ways to apply their work, while 184 150 people, 30 of whom came from abroad. Interestingly, only one- being firmly grounded in society. 185 Henk Nieboer – Ecoshape THE SHOWCASE EFFECT

END-USER PERSPECTIVE

Henk Nieboer is the director of the Ecoshape foundation, which Applied knowledge needs to be supported by fundamental manages the innovation programme Building with Nature, and knowledge. For this reason, Ecoshape has always supported the Consultant at Witteveen+Bos. Henk is also member of the board of NatureCoast program and strives to learn from it. One of the Deltares, Aventus, Cleantech Center, and W+B pension fund. strengths of NatureCoast is that is has been an interdisciplinary program. Building with Nature is a practice that requires that scientists and practitioners from various disciplines work together The growing world population and our increased welfare is putting and, thus, create results together. an ever-increasing burden on the world’s natural systems. Resources and once fertile soils are being depleted, and biodiversity is NatureCoast has concentrated its research on the Sand Motor. decreasing worldwide. Natural systems, however, do not exist in NatureCoast researchers have discovered that the main success isolation; they also provide services to us (ecosystem services). factors of the Sand Motor were innovation, interdisciplinary collaboration, and the showcase effect it had for the principle of To solve societal problems while preserving or even improving Building with Nature. the delivery of ecosystem services, we need better solutions than before. Solutions that take nature and natural processes as a starting That coincides with the main objective of Ecoshape: to stimulate point and not as boundary conditions. That means we should be innovation through interdisciplinary research work on showcase building with nature. projects. The Sand Motor and the NatureCoast research program have become examples of how to create a stimulating environment In the Netherlands the Ecoshape Foundation is coordinating the for research, development and innovation, with inspiration for many, innovation program “Building with Nature.” From the project’s start not least beyond the borders of the scientific community! in 2008, Ecoshape has considered the Sand Motor as an important living lab for Building with Nature concepts. As a consequence, we have always encouraged, supported and followed the NatureCoast program with great enthusiasm.

The focus of Ecoshape and its partners is very much on applied knowledge. Universities, research institutes, public and private parties join forces to create solutions based on Building with Nature principles; they study and monitor the behavior of the solutions and the system and try to learn from it. These results are translated into generic guidelines which are made available through the Ecoshape website (ecoshape.org). – REFLECTIONS Figure 1. (left page) A chronological compilation of aerial

photographs of the construction of the EIGHT Sand Motor in the period from March 3rd 186 until July 5th, 2011. 187 Jaap Kwadijk – Deltares LEARNING FROM NATURE-BASED SOLUTIONS

END-USER PERSPECTIVE

Jaap Kwadijk is Director of Science at Deltares, the Dutch Over the last two centuries, engineering has been extremely institute for applied research in the field of water, subsurface and successful in sustaining human life in deltas by learning from infrastructure. He is also a part time professor of Modeling Water countless failures and making subsequent improvements. The need Management and Climate at the University of Twente. to keep pace with increased urbanisation, rapid climate change, and sea-level rise makes the sustainability of deltas an immense In view of the recent discussions on sea-level rise, I think the challenge. This represents such a large challenge that we need to publication of this book is “just in time.” Over the last two years it rethink the capacity of our classical engineering approaches to keep has become increasingly clear that the possibility of accelerating deltas liveable in the 21st century. sea-level rise may become the greatest challenge for low-lying coastal areas like The Netherlands. If this rise occurs, solutions to The concept of nature-based solutions is often mentioned as the cope with it need to be found quickly. Engineering approaches silver bullet solution. And there are good reasons for that. They that make maximum use of natural processes, such as the Building can be cost-effective ways of reducing vulnerability, and they offer with Nature approach, seem to have the largest potential. However, multiple benefits to the environment and local communities. Think our experience with these solutions is limited. NatureCoast, the of sustaining livelihoods, improving food security and sequestering research program that studied the Sand Motor, one of the largest carbon. This explains why nature-based solutions are also attracting experiments with Building with Nature, has added to our knowledge. the attention of green investors. But our understanding of these Such experiments and knowledge are urgently needed. solutions and our experience with them is still very limited. Initiatives are often undertaken without a sound scientific basis. Pilots are also Pollard and DeConto published a paper in Nature in 2016 that woke generally too small to judge whether the solutions are applicable for the scientific community to the issue of sea-level rise. Their results larger areas. This is unfortunate, as the importance of learning by suggested that global warming could cause large parts of the ice doing can hardly be overrated. It took us 200 years of trial and error sheet of Antarctica to become unstable and slip into the sea more with traditional engineering to arrive at the high level we currently rapidly than has been anticipated. This slipping would increase the have. We do not have another 200 years to learn. contribution of Antarctica to sea-level rise to more than a meter this century. And once this mechanism has started, it will probably prove When designing these nature-based solutions, we need to seek to be irreversible. multiple benefits. Climate change solutions will never be done exclusively to deal with climate change, but only where they For many years, the debate about global sea-level rise had focused also meet other societal goals. We urgently need to identify how on differences in the order of decimetres, and the contribution of adaptation using nature-based solutions can help societies achieve Antarctica was expected to be quite small during the century. Today, their wider sustainability goals – for health, well-being, regeneration, the uncertainty regarding sea-level rise during the century is in the equity, and so on. In this way, we can make the societal relevance order of a meter, or even more, with Antarctica possibly becoming of responding to climate change clear.To maximize their impact, the largest contributor. experiments need to bring together climate science, earth system science, and environmental science. This will improve the ability of On top of that, a recent paper published in Nature (Trusel et al. 2018) scientists to make integrated predictions about the impact of large- concluded that the Greenland ice sheet is also melting faster than scale nature-based solutions. This will also create a generation of ever before. In October 2018 a special report of the United Nations’ scientists with more experience with multidisciplinary research. Intergovernmental Panel on Climate Change concluded that the

remaining time window to cut greenhouse gas emissions so that NatureCoast delivered much of this. It evaluated a full-scale – REFLECTIONS global warming is limited to 1.5 degrees Celsius is now disturbingly experiment, not only addressing engineering aspects, but also narrow, 12 years. Unfortunately, we are not yet on track to reach providing guidance for implementing nature-based solutions at

these goals, as the recent figures on emissions show that global this large scale. The stories about this research experiment are EIGHT carbon emissions in 2018 have jumped to an all-time high. So my spectacular and will attract young scientists. The many kite surfers 188 message is crystal clear, we need to accelerate adaptation. and walkers show the pleasure that nature-based solutions can bring. 189 Figure 1. Roeland Allewijn – Rijkswaterstaat Panel "Reflection on interdisciplinary research" at Final Conference NatureCoast in September 2017 at TU Delft. MULTIDISCIPLINARY RESEARCH TO INFORM SOCIETY From left to right: Roeland Allewijn, Rijkswaterstaat; Baukje Kothuis, TU Delft; AT LARGE Henk Nieboer, Ecoshape (Page 188); and Jaap Kwadijk, Deltares (Page 190). END-USER PERSPECTIVE

Roeland Allewijn is Director Safety and Water Use at Rijkswaterstaat, “hard” natural science and social science inevitably come together. department Water, Transport and Living Environment (WVL). As a result, these projects can only be completed by combining research from different disciplines.

For Rijkswaterstaat, the Sand Motor is unique, and that has much to As manager of the Sand Motor I would like to mention two specific do with the concept “Building with Nature”: working with nature and things that NatureCoast has contributed to. First, the NatureCoast letting nature do part of the work. That is a kind of “flip-thinking”, as researchers produced high quality data. In addition, and directly it differs strongly from traditional hydraulic engineering. The Sand linked to this, they set up an excellent data management system. Motor is one of the first really large-scale applications of the Building NatureCoast paid close attention to not only collecting and storing with Nature concept. In addition, the idea of a “sand motor” has the data properly, but also making it easily accessible to everyone. rarely been implemented in practice. It is therefore truly unique that As an end-user, we can continue to build on this after the research we dared to do this in the Netherlands, and on such a scale. program, and that is of immense value to us.

While Rijkswaterstaat is formally the end-user of the knowledge developed in this research program, who is ultimately the end user of the Sand Motor? I think it is society, with our overarching goal of wanting to live safely in the Netherlands. Of course, a large project like this only becomes worthwhile when a good cost-benefit ratio has been established, and making this analysis was one of our tasks at Rijkswaterstaat. Beyond the cost-benefit analysis, a key task for us as the manager of the Dutch coast is to keep our knowledge of flood risk management cutting edge. We endeavor to fulfill that task more and more from the perspective of ecological responsibility and sustainability. That is the future goal.

Rijkswaterstaat is part of the so-called "Golden Triangle” in the pilot Sand Motor: knowledge institutions such as the universities and Deltares, governmental parties tasked with managing and implementing the project, and market parties - the hydraulic engineers and the engineering firms. In order for this Golden Triangle experiment to work, input from each of these three legs was essential. One can propose everything, but for a plan to really come together one needs to know about the entire coastal system as well as have solid modeling results and field measurements. The scientific basis is necessary for a successful project.

Multidisciplinary research at the Sand Motor is crucial for Rijkswaterstaat. Our assignments are no longer one-dimensional,

and today we no longer look just at hydraulic aspects and the – REFLECTIONS morphological system. We also require insight into the ecosystem, and need to know how to optimize a design from a sustainability

perspective, for example making it energy neutral. Knowing how EIGHT to deal with the environment and with involved stakeholders is also 190 indispensable. In such complex projects, the different aspects of 191 Figure 1. (right) Jill Slinger – Delft University of Technology Integration by postdocs was envisaged as mediating the influence between Knowledge development and Utilization in the original THE INTERDISCIPLINARY CHALLENGE NatureCoast proposal. Revisions for the future are proposed in red based on experiences with the NatureCoast program. ACADEMIC PERSPECTIVE

Jill Slinger is an associate professor at the Faculty of Technology, a series of individual research pathways towards a concerted, Policy and Management at Delft University of Technology. She common research endeavor, and represents a significant milestone was involved in the development of the NatureCoast program in research integration. proposal and has worked to integrate the governance research within the program. Second, we have research at the governance - ecosystem services interface that produced a scientific paper by Van Oudenhoven et al. Figure 2. (below) (2018) entitled "Mind the Gap" (Page 138). Unlike the MEGAPEX2014 The Mega Perturbation Experiment, Interdisciplinary research can be compared to the ancient craft of campaign, which integrated different technical fields, this project MEGAPEX2014, conducted on the Sand weaving a fishnet. The knot used for this net is obviously important. attempted to bridge the hypothesis-based and social constructivist- Motor in September and October 2014, The quality, size and form of the final product depends on the skill based sciences. The paper represents the culmination of a an inter-organisational, national and of the weavers, the choices they make in the design and their shared research endeavor between the PhD researchers studying international multidisciplinary collaboration ability to picture how the different components will come together governance (Chapter 2), postdocs on governance and ecosystem that represented a milestone in NatureCoast to form a useful whole. By analogy, when conducting a large, services (Page 138), and senior scientists. During the research for this integration. (Photo by Timothy Price) multidisciplinary project, the scientific methods (the knots), the paper, a number of issues had to be resolved: consistent text coding skills of the scientists (the weavers), the initial choices made for in the governance study, ethical considerations (e.g., potentially the project design, and the scientists’ collective ability to integrate using interview data for purposes other than originally indicated their findings across disciplines to form a synthesized whole, will to the interviewees), and correctly interpreting ecosystem services determine the quality, number and form of the final products. In the terms used in the interviews. Contrasts were discussed between NatureCoast project, scientists from six disciplinary research themes normative interpretations of the ecosystem services concept and the (see Chapter 1) met with the end-users to design the research "logic of appropriateness" that underpins strategic decision making. approach at the proposal stage. From the outset, they hoped that This gradually led to a novel conceptualization that could be used the broad approach would produce useful interactions between to understand whether and how ecosystem services played a role knowledge development in different disciplines and utilization in in decision making on the Sand Motor. In my opinion, this research the field (Figure 1). But, did the anticipated integration occur, and exemplifies the interdisciplinary integration hoped for when the did it produce the desired interactions between the development of NatureCoast project was first proposed. knowledge and practical applications? On a critical note, senior scientists contributed little to integration in To address this question, let me give two positive examples, as well the NatureCoast program. This was not from lack of interest or an as one critical note. First, there is the six-week multidisciplinary unwillingness to collaborate across disciplinary divides, but rather field measurement campaign, the Mega Perturbation Experiment, inherent to the way research is funded. Only the senior scientists in or MEGAPEX2014, conducted on the Sand Motor in September and the project management team received (limited) compensation for October 2014 (Figure 2; also Page 74). The campaign was their time, and others received no funding. This limits the time and set up in conjunction with Rijkswaterstaat and the NEMO research effort that they can devote to interdisciplinary tasks. In my view, project of Delft University of Technology (Page 19). It represents this is the single factor that most limits enhanced integration and a triumph of inter-organizational, national and international interdisciplinary collaboration in Dutch science today. collaboration that generated a unique set of data covering bathymetry, sediment composition, currents, the surf zone, beach In conclusion, the anticipated interactions between knowledge and dune morphology, dune vegetation, fish and bird counts, development and utilization were seen in MEGAPEX2014, the

groundwater levels, geochemistry, wave height, salt spray, and bi-annual user meetings, and the paper on integrating governance – REFLECTIONS sand transport into the dunes. The field measurement campaign and ecosystem services. However, interdisciplinary integration succeeded in forging bonds between the PhD researchers, could be improved by specifying integrative arrangements and

postdocs and their supervisors, particularly those focused on governance arrangements at the research proposal stage in future EIGHT understanding the biogeomorphological evolution of the Sand (indicated in red in Figure 1), and by funding the involvement of 192 Motor. The campaign transformed the NatureCoast project from senior scientists in interdisciplinary integration. 193 Mark van Koningsveld – Van Oord & Topsector Water NATURECOAST AS ONE OF THE FIRST “LIVING LABS”

END-USER PERSPECTIVE

Mark van Koningsveld is a professor of Ports & Waterways at Delft to the active role of the EcoShape consortium at the time of the University of Technology and Manager R&D Engineering at Van Oord. NatureCoast project. Normally, developing a shared database takes Mark is also secretaris Topteam at Topsector Water & Maritiem. a lot of time, but the OpenEarth system already developed within EcoShape was adopted, meaning that a well-developed system including clearly documented protocols was available right from The NatureCoast project was a unique project because it brought the start. This made it easier to store all data from NatureCoast together several puzzle pieces in space and time. The pilot Sand and make it available to researchers during and even after the Motor pilot was conceived, designed and implemented at a time NatureCoast project. Just as NatureCoast learned from previous when the EcoShape consortium was actively promoting the work conducted within EcoShape, the NatureCoast example has “Building with Nature” concept. This had already resulted in now become a useful guide for subsequent projects and proposals. well-established relationships between researchers from different This approach, developing a project based on preceding ones, is backgrounds from all over the Netherlands, as well as with clearly working and should be continued. practitioners. This in turn contributed to a basic research agenda for the Sand Motor that truly integrated different disciplines, and was All these elements together have surely contributed to making the also broadly supported. This broad support resulted in substantial NatureCoast project so successful, and as a result the NatureCoast co-funding contributions by parties like Rijkswaterstaat, Van Oord, approach has become an example for many research programs that Boskalis, Deltares and Wageningen Marine Research (contributing are being developed. The benefits of aligning research programs, €1.4 million cash & in-kind out of a total project budget of field experiments and data management have clearly been €5.1 million). This provided a huge boost to the project. demonstrated, and I hope that we will see more projects in the near future that use a similar approach. The NatureCoast project was coupled to an unprecedented field experiment in the form of the pilot Sand Motor. This resulted in a tangible research object, where the researchers could physically convene and discuss. Today, the term “Living Lab” is frequently mentioned, which is an instrumented physical environment for research and evaluation. When NatureCoast started, this was still not such a common concept, but policy makers currently expect Living Labs to help bring academic research closer to practice (vertical integration). Furthermore, working on a physical pilot project is expected to encourage researchers from different disciplines to work together more closely (horizontal integration). I am sure that positive experiences during the NatureCoast project contributed to the current popularity of Living Labs.

Due to the nature of acquiring research funds, and the generally very low success rates, it is normally extremely difficult to obtain funding for a field experiment on the scale of the Sand Motor. Fortunately, this worked almost perfectly in the case of NatureCoast.

It must be said that Delft University of Technology was very – REFLECTIONS proactive, starting some of the valuable bathymetry measurements even before the final grant was awarded. EIGHT Data was shared in a common format, and a centralized database 194 was successfully constructed. This was again presumably due 195 Todd Bridges MESSAGES FOR THE INTERNATIONAL COMMUNITY

EPILOGUE

Todd Bridges is the U.S. Army's Senior Research Scientist for the most difficult steps on the path to innovation is institutionalizing Environmental Science. He is the National Lead for the Engineering a new discovery or invention, e.g., translating new knowledge and/or With Nature® initiative of the U.S. Army and U.S. Army Corps of technology into new policy and standards. It must be understood that Engineers. This initiative includes a network of research projects innovation is not truly achieved until the new approach is put into and field demonstrations to promote sustainable and resilient practice. infrastructure systems. People want and expect diverse value from projects. There may have been a time when everyone was satisfied with a project that The Sand Motor is an extraordinary project, as evidenced by its delivered a single-purpose value, e.g., a flood risk reduction project scope, the diversity of its components, and the investment in that produced positive economic benefits in the form of avoided research that was integrated into the project. As such, it provides damages, and nothing more. Currently, government authorities, an appealing vehicle for illustrating four important messages for the project sponsors, partners, stakeholders and the public increasingly international community. expect projects to produce multiple streams of value, including environmental and social value in combination with economic Big problems call for big solutions. There is some comfort to be benefits. The exciting challenge of the 21st century is to plan, design found in small projects. Small projects may (sometimes) be more and build such multi-purpose projects. This presents many specific manageable. Large projects may (sometimes) entail more execution challenges to practitioners, notable among these is the issue of risk. However, many of the challenges we confront in the context of governance. By their very nature, multi-purpose projects will involve water infrastructure, coastal management, flood risk management— more partners, interests, and stakeholders. As a consequence, the e.g., climate change, sea-level rise, coastal storms—cannot be social complexity and dynamics of the project will be more central addressed in a piecemeal fashion. These and other challenges pose to the success of a solution and a project team’s membership and big problems that call for big solutions, which can operate over large capabilities will need to reflect this fact. spatial scales, include many component parts and facets, and unfold and mature over long timescales. For these reasons and others, Value is magnified by translation. The Sand Motor project has many developing big solutions requires the use of a systems approach to lessons to teach practitioners working on sandy coasts. Making the project development. Becoming successful overtime with executing effort to learn those lessons and then share them with others (as done big solutions will involve some “learning by doing,” at the individual through this book and other products) provides a means for others and organizational level, as experience is gained in developing and outside the project team to learn, apply and produce value in the implementing comprehensive, system-scale solutions. form of new projects. It is commonly understood, though perhaps not universally, that solutions to complex problems along sandy coasts Innovation is achieved by granting yourself license to experiment. cannot be produced with a “cookie cutter” -what worked in one place/ Innovation is hard. The easy path is to copy yesterday’s project context may not work in another- because the particulars matter. to address tomorrow’s problem. The easy path may work over However, there are many types of lessons. One lesson illustrated by the short-term, but eventually the easy path ends in failure and the Sand Motor, and other projects around the world, is the great sometimes catastrophe. For organizations that are responsible for potential to produce value through strategic placement of sediment, infrastructure, innovation is the outcome of intentional, coordinated i.e., placing sediment at one location with the plan that natural decisions at multiple levels — in other words, it is an organizational processes will move it to other locations to achieve specific purposes - choice. In a sense, organizations must grant themselves permission leveraging nature’s forces rather than trying to control or defeat them.

or license to try something different, accepting and managing the There is a great need and opportunity for action, worldwide, to create – REFLECTIONS: RESEARCH IN APPLIED CONTEXT risks involved in enterprise-level experimentation. The “reward” for value by restoring landscape features and processes along coasts taking those risks is discovering a new and better solution. It may be and rivers that depend on sediment. By sharing our experiences in

difficult for organizations to accept the fact that there will be failures implementing these projects across disciplinary boundaries and EIGHT (or, if you prefer, less than fully successful projects) along the path organizational borders, we will magnify the value of our collective 196 to innovation — however, “nothing ventured, nothing gained.” One of efforts across the community of practitioners worldwide. 197 Stefan Aarninkhof THE SAND MOTOR: STEPPING STONE FOR A COASTAL CLIMATE LAB? EPILOGUE

Stefan Aarninkhof is a professor of Hydraulic Engineering at Delft and the feasibility of the Paris agreements on the reduction of

University of Technology. He holds the chair of Coastal Engineering, CO2 emissions. Such rates of sea-level rise are associated with an which he took over from emeritus professor Marcel Stive. Stefan enormous increase in the need for beach nourishments worldwide. Aarninkhof was both involved with the genesis of the Sand Motor and For the Dutch coast for instance, Deltares recently estimated an NatureCoast, and lead the NatureCoast project during the final phase. increase of the annual nourishment volume ranging from a factor 3-4 (for a 0.4 m rise) up to a factor 20 (for 2 m sea-level rise in 2100). This corresponds to tens of millions cubic meters per year, worst Worldwide, the Sand Motor is considered an icon of Building with case well above 100 million m3/year. Nature. Its unique character and ever changing coastal landscape raise the permanent interest of scientists, engineers and managers. Technically, these volumes are feasible – it was achieved in the past Over the years, the Sand Motor has taught us many important for major land reclamations like the Palm Islands (Dubai, UAE) and lessons. the Maasvlakte II (The Netherlands). However, many questions arise if assessing the feasibility of such mega-scale nourishment programs Lessons on the importance of early stakeholder engagement. Long for highly-developed, densely populated shorelines: How to optimize before the preparation of any engineering design, the Sand Motor the required sand volume and what is the most efficient way to initiators showed the wisdom to engage key stakeholders in a place it in the nearshore? How to minimize ecological impacts and pre-project ambition agreement. This agreement, signed in 2008, maximize benefits for nature? How to accommodate added values explicitly stated distinct objectives for coastal safety, nature and for other functions like recreation and freshwater supply, and how recreation, and innovation. In the years that followed, this multi- to predict the long-term evolution of these benefits so that they can objective approach governed key decisions throughout project form the basis for an integral financing scheme? And finally, how development and shaped the Sand Motor as we know today. to generate societal support for sandy coastline extensions as a sustainable measure for climate change adaptation? Lessons on the importance of a full-scale demonstration project. Both the complex interplay of morphological and ecological Bearing in mind the lessons of the Sand Motor, the time is there to processes, as well as societal response to large-scale coastline start preparations for a Climate Lab Coast: a large-scale seaward changes can only be studied in the real world. Besides, a tangible extension of the shoreline, along a 15-25 km stretch of coast with pilot project encourages focus of research efforts, and helps the goal to create a climate-resilient coast while adding value for to bridge the gap between academic science and coastal zone nature, economy and society. Such full-scale pilot implementation management practice. would enable us to address the questions raised above. It will yield indispensable insights in the eco-morphological, economic and Lessons on the importance of multidisciplinary collaboration. societal feasibility of large-scale nourishment programs for different NatureCoast has clearly demonstrated the added value of a sea-level rise scenarios, including the maximum level beyond multidisciplinary research program. Key to success was the which upscaling of present-day policies is no longer possible and continuous strive for demand-driven research, realised by fundamentally different solutions are to be explored. In this way, we embedding twelve fundamental research studies in an interactive, are timely prepared for the nourishment of hundreds of kilometres interdisciplinary working environment. This resulted in improved of shoreline that need to be treated afterwards. awareness of the broader impact of the work. In this way, NatureCoast has played an eminent role in raising the future leaders I wish that future generations of coastal engineers, scientist and

in coastal science and engineering. managers will conclude that the Sand Motor and its associated – REFLECTIONS: RESEARCH IN APPLIED CONTEXT NatureCoast program have been the stepping stone for successful These are the lessons we should take along while addressing the implementation of large-scale nourishment programs, as a

major challenge we are presently facing: climate change. Projections sustainable solution for climate change adaptation along highly- EIGHT for climate-induced sea-level rise range from 0.4 to 2 m in 2100, developed, densely populated shorelines. 198 depending on uncertainties in the collapse of Arctic ice sheets 199 Groups of Grote Sterns (Sandwich Tern) and Visdieven (Common Tern) visiting the Sand BIBLIOGRAPHY NATURECOAST Motor for a few days before heading to warmer regions. One of the Sandwich Sterns (ring number: W-N75) spends NatureCoast researchers in bold the Dutch winter period in the southern hemisphere where he has been seen in Namibia (Source: birdring.nl). (Photo by Marius van der Flier)

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THE SAND MOTOR: A NATURE-BASED RESPONSE TO CLIMATE CHANGE FINDINGS AND REFELECTIONS OF THE INTERDISCIPLINARY RESEARCH PROGRAM NATURECOAST

Edited by Arjen Luijendijk and Alexander van Oudenhoven

Production B Business Energy, Amsterdam Graphic design & cover design steef liefting English language advice Sören Johnson All interviews by Baukje Kothuis

Publisher Delft University Publishers, TU Delft Library Printing Quantes Printers, Rijswijk

Publication of this book has been funded Special thanks to Image courtesy: by NWO-TTW: Dutch National Science Matthieu de Schipper for proofreading - Front and back cover: Foundation - Applied and Engineering the final draft of this book. His sharp eye Rijkswaterstaat Beeldbank, beeldbank.rws.nl Sciences (formerly NWO-STW) as part of and constructive feedback have been - Page 2: Perspectief Program NatureCoast (P11-24). indispensable. Evert van de Worp - Pages 8, 23, 25, 29, 45, 50, 54, 47, 76, 79, 81, Boskalis, Deltares, Province of South 106-107, 109, 131, 133, 138, 140, 148, 154-155, Holland, Rijkswaterstaat, Van Oord and 179, 181, 186, 188, 194, 196, 198: Wageningen Marine Research, for making Rijkswaterstaat Beeldbank, beeldbank.rws.nl the contents of this book possible by - Page 104: funding the NatureCoast program. In Bas Hoonhout particular, Rijkswaterstaat for sharing all - Page 126: Copyright © 2019 by editors and authors data of the monitoring program. Simeon Moons unless otherwise stated. All rights reserved. - Page 184 (Figure 3): The sources used in preparing this book All end-users of the NatureCoast program Rijkswaterstaat, Frouwkje Smit have been identified to the best of our for sharing their knowledge, data and time. - Pages 184 (Figures 2 and 4) and 190: ability and we have requested and been We hope that this book does justice to Deltares, Welmoed Jillerda. granted permission to use the materials the research to which you contributed so where was deemed appropriate. If a source actively and enthusiastically. For all other images and photos courtesy is has been incorrectly identified or appears mentioned in the caption of the figure when without the appropriate permission, please requested, or was freely granted by authors, contact the publisher and/or editors. editors and interviewees concerned.

NUR 950 204 ISBN 978-94-6384-021-7 RESEARCH PROGRAM NATURECOAST – CLIMATETO CHANGE RESPONSE NATURE-BASED A MOTOR: SAND THE Contributors Aarninkhof, Stefan 198 THE SAND MOTOR: A NATURE-BASED RESPONSE Aerts, Rien 128 Allewijn, Roeland 190 Aukes, Ewert 12, 28, 30, 38 TO CLIMATE CHANGE Bacon, Patrick 154 Baptist, Martin 130 Bierkens, Marc 176 FINDINGS AND REFLECTIONS OF THE INTERDISCIPLINARY Bodegom, Peter van 148 Bontje, Lotte 34, 168 Boer, Cor de 6 RESEARCH PROGRAM NATURECOAST Bressers, Hans 42 Bridges, Todd 196 EDITED BY Dwarshuis, Lenie 22 Egmond, Emily van 122 Arjen Luijendijk Flikweert, Jaap 180 Alexander van Oudenhoven Gelder, Carola van 24 Heerema, Jacqueline 152 Heijer, Kees den 150 Arjen Luijendijk (right) was active in the NatureCoast Herman, Peter 126 program as a postdoctoral researcher at Delft Hoonhout, Bas 100 University of Technology from the start in 2013 Huisman, Bas 62 until the end in 2018. He focused on setting up the Huizer, Sebastian 66 interaction between the PhD researchers and Kleij, Hans 46 end-users, as well as integrating the research findings. Koningsveld, Mark van 194 He worked on developing integrated model forecasts

Kothuis, Baukje interviews (eds) Oudenhoven Van and Luijendijk and developed the world’s first global beach erosion Kwadijk, Jaap 188 map. He is currently working as a Specialist at Linnartz, Leo 132 Deltares and as a researcher at the Delft University Luijendijk, Arjen 12, 50, 52, 84, 86, 138, 142, of Technology on predicting the future behavior of 146, 158, 160, 164, 166, 170, 172, 174, 184 the world’s beaches. Moons, Simeon 114 Mulder, Jan 78 Alexander van Oudenhoven (left) was active in the Nieboer, Henk 186 NatureCoast program as postdoctoral researcher at Nolet, Corjan 96 Leiden University between 2015 and 2018. He focused Oude Essink, Gu 176 on integrating the program’s scientific findings, Oudenhoven, Alexander van 12, 112, 136, thereby looking at the potential benefits that nature- 138, 142, 146, 164, 168, 170, 184 inclusive coastal management can generate and how Ovink, Henk 2 these are perceived. He is currently working as an Pit, Iris 70 assistant professor at the Institute of Environmental Post, Marjolein 118 Sciences at Leiden University, working on the Price, Timothy 74 interface between biodiversity, ecosystem services Puglia, Michel 80 and societies’ quality of life. In the spring of 2018, he Puijenbroek, Marinka van 92 NatureCoast is the largest research program that focused on the The NatureCoast program was carried out by a consortium became Co-Editor in Chief of Ecosystems and People, Radermacher, Max 54 Sand Motor, a large sandy peninsula, constructed in 2011 on the Dutch of knowledge institutes and universities, and the research was an interdisciplinary open access scientific journal. Ruessink, Gerben 76 North Sea coast near The Hague. This unprecedented pilot project conducted in cooperation with end-users from private companies, Rutten, Jantien 58 involved placing 21.5 million m3 of sand on and in front of the beach research institutes and governmental organizations. The Dutch Schipper, Matthieu de proof read with the aim that it would spread along the coast. The Sand Motor Technology Foundation (NWO-TTW) provided the largest share Slinger, Jill 192 is a unique beach nourishment due to its size, the design philosophy of the project funds. The research in NatureCoast focused on six Stive, Marcel 4 behind it, and its multifunctionality. It combines the primary function themes: coastal safety, dune formation, marine ecology, terrestrial Thiel de Vries, Jaap van 160, 178 of coastal protection with the creation of a new natural landscape ecology, hydrology and geochemistry, and governance. This book Valk, Bert van der 108 that also provides new leisure opportunities. From the outset, presents countless facets of the Sand Motor, but we also hope it Vertegaal, Kees 106 “learning by doing” has been a crucial part of the project and demonstrates the scientific merits of interdisciplinary research and Vikolainen, Vera 166 NatureCoast was an integral part of this. Because of its innovations, how, ultimately, societies can benefit from it. Waterman, Ronald 46 the Sand Motor has triggered considerable political and scientific Wijnberg, Kathelijne 104 interest from all over the world. Broad research consortia were NUR 950 Williams, Isaac 88 formed to conduct interdisciplinary research on the Sand Motor. ISBN 978 94 6384-021-7