Flood-resilient urbanity along the Meuse Safe-fail design suggestions Johnny Boers & Simon Pille - Thesis landscape Architecture 1 Flood-resilient urbanity along the Meuse June 2009 Wageningen University and Research Centre Master Landscape Architecture & Spatial Planning Major Thesis Landscape Architecture (lar 80436) Signature Date Author: J. (Johnny) Boers Bsc Signature Date Author: S.C. (Simon) Pille Bsc Signature Date Examiner Wageningen University: Prof.Dr. J. (Jusuck) Koh Signature Date Supervisor and examiner Wageningen University: Dr.Ir. I. (Ingrid) Duchhart Co-supervisor Deltares: Ir. M.Q. (Maaike) Bos © Johnny Boers & Simon Pille, Wageningen University, 2009 All rights reserved. No parts of this report may be reproduced in any form without permission from one of the authors. [email protected] - [email protected] Flood-resilient urbanity along the Meuse Safe-fail design suggestions Johnny Boers & Simon Pille - Thesis landscape Architecture 6 Preface For eight long years, we have studied landscape architecture at the will actually work. Disappointed, but not defeated, we went on in Wageningen University and Research Centre. During this period, our search for a safe urban environment. With a lot of effort and we were educated in designing new functioning and attractive regained positive energy, we were able to do so. In this thesis, you landscapes by using the existing landscape and its processes. Now, will find the result. we are able to end our study with this thesis, which will show what we have learned in this phase of our lifetime. We would never have been able to finish this thesis without some people though. Foremost we would like to thank Ingrid Duchhart, We have chosen for a thesis that focuses on water and urban our supervisor. Without her assistance and positive attitude, it would landscapes. Living in a densely populated delta country facing a have been a lot harder to finish this thesis. We thank her for the time changing climate does give some incentives to do so. But the fact that she spent on us, especially since it might have exceeded the that we both have affinity with water might also have been a reason. time that is granted by university rules. We also thank Roel Dijksma We both believe that the old method of flood-protection is not the for the hydrological input during this thesis. We thank Maaike Bos best way to cope with the changing climate. During our study, we for her matter-of-fact approach and structural advice on the subject. have become aware that working with the natural processes instead We would like to thank the people of Rijkswaterstaat, which we of working against them will have far better result. Therefore, this could always contact for hydrological questions and data. They study presents an example of how the Dutch people can work with have been so fast with replying that we were forced to change our water, not fighting against it. This might ask for a complete change idea of public servants. We thank our family for their comforting and in culture, but it might be worth it. financial support. We thank our friends for their critical advice and positive support during this thesis. And last but not least we thank We started this thesis with a positive attitude, but halfway through our girlfriends. They always took care of us and they have been an it became very grim. We became aware that our goal could not anchor of rest and hope during this hectic period, even tough they be reached in the way we had envisioned it. Our plans of making had to put up with grumpy, absent-minded and tired boyfriends. beautiful streets and parks that at the same time could protect the people against floods could not be realised. It simply would not solve In return, we hope we can all impress and inspire you with this the problem. This has been a real eye-opener for us. For the first thesis! time we became aware that just because it is possible to envision a solution to a problem, this does not mean that such a solution Johnny Boers & Simon Pille 7 8 Abstract In the future the Meuse valley in Limburg will face higher water levels because of climate change. The dikereefs of Limburg have stated that the current dike system has reached its limit and the safety of the inhabitants of urban landscapes in the floodplain of the Meuse cannot be guaranteed during an expected river discharge of 4600 m3/s. Other approaches of dealing with the predicted amount of water have to be investigated. Dikes cannot be heightened endlessly and they only reduce the chance of flooding, instead of the risk of flooding. We envision that the flood risk of the urban landscapes has to be reduced and flood-resilience was expected to do so. We researched by designing whether it was possible to replace the current dike system by an ultimate flood-resilient system. These designs were assessed with calculations, thereby giving the potentials of: • Parks and streets as storage basins and bypasses respectively. • Large scale interventions in the urban landscape like large basins and bypasses. • Flood-resilient adaptations of buildings in the floodplain. However, the space that is required to construct basins and bypasses with the required capacity exceeds the area of the urban landscape. In case of the building adaptations, the flow speeds and water levels in case of flooding were too high and the constructions would be damaged. Furthermore, the surrounding urban space would become a dangerous area in case of flooding. So the conclusion had to be that ultimate flood-resilience in the valley of the Meuse cannot be a good replacement of the current chance-reducing interventions. Next, we investigated if flood-resilience could enhance the current chance-reducing approach. This also proved to be impossible, because the expected water levels and flow speeds remained too high. Therefore, the conclusion had to be that flood-resilience can not cope with the expected discharges in the current landscape of the Meuse valley. We then searched possible other approaches that could guarantee a safe living environment in the Meuse floodplain. The only option that remained after this search is raising the urban landscapes, with as result several mounds in the floodplain of the Meuse. By law, the height of the mounds is limited to the height of the current dikes, because they would raise water levels further upstream otherwise. Consequently, the mounds can still flood when the middle scenario of the KNMI becomes reality. Therefore, flood-resilient interventions need to be applied on top of the mound, which can now be done because of the lower water levels and flow speeds. Several design suggestions for such urban landscapes are presented in this thesis. Keywords: flood-resilience, Meuse, flood-risk, flood-chance, mound, Limburg, urban landscapes, dikes, landscape architecture, safety, river, climate change, safe-fail, floods 9 Table of contents 1. Introduction 13 7.3 Different categories of flood-resilience 73 1.1 The main problem, goal and hypothesis 14 7.3.1 Area-adapt 74 1.2 Research process and methods in retrospect 15 7.3.2 Point-adapt 75 1.3 Reading this thesis 19 7.4 Technical analysis of the different categories 76 7.4.1 Store (Basin) 76 2. Landscape of the Meuse basin 21 7.4.2 Channel (Bypass) 77 2.1 Description of the Meuse basin 22 7.4.3 Evade (Floating, amphibious, on poles and 79 2.2 Historical development of the landscape along the 24 mounds) Meuse in the Netherlands 7.4.4 Resist (Water-resistant house) 83 2.3 Division of landscapes along the Meuse 27 7.4.5 Endure (Wet-proof house) 84 2.3.1 Division based on surrounding landscape 27 7.5 Conclusion 85 2.3.1 The undiked and diked Meuse in the 30 Netherlands 8. Asses flood-resilience in the Meuse valley 87 2.4 Conclusion 30 8.1 Area-adapt 88 8.1.1 Storage 88 3. Aspects and history of floods in the Netherlands 31 8.1.2 Channel 90 3.1 Effects of flooding 32 8.1.3 Conclusion concerning area-adapt 92 3.2 History of floods and flood protection in the 32 8.2 Point-adapt 93 Netherlands 8.2.1 Assessment of the evade, resist and 93 3.3 Floods of 1993 and 1995 36 endure methods 3.4 Conclusion 37 8.2.2 Conclusion concerning point-adapt 95 8.3 Conclusion area-adapt and point-adapt 95 4. Climate change 39 4.1 The process of climate change 40 9. Flood-resilience supplementing current approach 97 4.2 Global climate changes in the future 41 9.1 Combination of approaches 98 4.3 Expected effects of global warming in Europe 42 9.2 Technical possibilities of the combination 99 4.4 Climate change in the Netherlands 42 9.3 Safety and liveability aspects 100 4.4.1 Predictions for the Netherlands 42 9.4 Conclusion 100 4.5 Conclusion 44 10. Remaining choices for the Meuse floodplain 101 5. Flooding problem of the Meuse valley 45 10.1 Using the upstream area in Belgium 102 5.1 Water level prediction projected on the landscape 46 10.2 Using the floodplain in southern Limburg 102 5.2 Categorization of the urban landscapes 48 10.3 Leaving the floodplain 103 5.3 Conclusion 51 10.4 Continuing on the current path 104 10.5 Raising the urban landscapes 104 6. Current approach 53 6.1 Policy and future policy explorations 54 11. Analysis of Arcen 105 6.1.1 De Maaswerken 54 11.1 Choice for Arcen 106 6.1.2 Integrale Verkenning Maas 54 11.2 Description of Arcen 106 6.1.3 Integrale Verkenning Maas 2 55 11.3 IVM around Arcen 109 6.1.4 Beleidslijn Grote Rivieren 57 11.3.1 The IVM measures around Arcen 109 6.2 Safety 57 11.3.2 Effects of the IVM measures 111 6.2.1 Policy of safety 57 11.4 Conclusion 111 6.2.2 Safety in daily life 58 6.3 Flood chance and flood risk 59 12.