Examples of multifunctional flood defences working report Mark Z. Voorendt EXAMPLES OF MULTIFUNCTIONAL FLOOD DEFENCES - working report - Mark Z. Voorendt August 10, 2015 Picture on the cover page: Quay of Doesburg, Netherlands 2012 (picture by the author) PREFACE This working document is part of my research on the ’evaluation of multifunctional flood defences’. The research is part of the programme on ’integral and sustainable design of multifunctional flood de- fences’ which is subsidized by and being carried out in commission of the Dutch Technology Founda- tion STW. This programme is one of the ’perspectief’ programmes that have the character of consortia of research institutes and users. The research programme consists of several projects in which various aspects of multifunctional flood defences are dealt with. These include technical aspects (strengths and loads), safety philosophy, governance, architecture and financial aspects. For details of the programme, one is referred to the project proposal (see the information on www.flooddefences.nl). The current project on structural evaluation is being carried out under supervision of promoter prof.drs.ir. Han Vrijling and with help from ir. Wilfred Molenaar, dr.ir. Jarit de Gijt and dr.ir. Klaas Jan Bakker, all working at Delft University of Technology. The research project is externally supported by Wit- teveen+Bos (especially ir. Paul Ravenstijn and ir. Gerben Spaargaren), Arcadis (dr.ir. Marco Veendorp and dr.ir. Hessel Voortman), Deltares (dr.ir. Meindert Van, ir. Han Knoeff and ir. Harrie Schelfhout) and STOWA (ir. Henk van Hemert). I also got much support from many (other) employees of the Department of Hydraulic Engineering of Delft University of Technology, especially prof.dr.ir. Bas Jonkman, prof.dr.ir. Matthijs Kok, prof.dr.ir. Marcel Stive, ir. Ad van der Toorn, ir. Henk Jan Verha- gen, dr.ir. Paul Visser. All their support is highly appreciated! This research is supported by the Dutch Technology Foundation STW, which is part of the Netherlands Organisation for Scientific Research (NWO), and which is partly funded by the Ministry of Economic Affairs. Any comment on this work is most welcome! Mark Voorendt Delft, August 10, 2015 i CONTENTS 1 Introduction 1 1.1 Definition.........................................1 1.2 A flood defence structure as part of a system.......................3 1.3 The difference between a flood defence structure and a water retaining wall.......3 1.4 Multifunctionality: Integration of functions........................3 1.4.1 Secondary functions................................3 1.4.2 Spatial integration.................................6 2 Examples of multifunctional flood defences9 2.1 Arnhem..........................................9 2.2 Deventer......................................... 11 2.3 Doesburg......................................... 13 2.4 Dordrecht......................................... 15 2.4.1 The Voorstraat................................... 15 2.4.2 The Noordendijk.................................. 16 2.5 Düsseldorf........................................ 21 2.6 Emmerich am Rhein................................... 22 2.7 Hamburg......................................... 27 2.8 Kampen.......................................... 32 2.9 Katwijk aan Zee...................................... 36 2.9.1 The final design.................................. 36 2.9.2 The ’wall-in-dunes’ alternative design....................... 39 2.10 Nijmegen......................................... 41 2.11 Rotterdam........................................ 45 2.12 Scheveningen....................................... 49 2.13 Sliedrecht......................................... 51 2.14 Tiel............................................ 58 2.15 Zaltbommel........................................ 60 2.16 Zutphen.......................................... 61 2.17 Zwijndrecht........................................ 64 A Glossary 67 iii iv CONTENTS References 71 1 INTRODUCTION 1.1. DEFINITION A flood defence is a hydraulic structure intended to protect land from irregular covering by water1. This seems a correct and useful definition, and it comprises the four main categories of flood defences mentioned in (TAW, 1998): 1. dunes 2. soil structures (dikes, dams) 3. specific water retaining structures (cofferdams, gravity walls, sheet pile walls, etc.) 4. engineering works (sluices, locks, cut-offs, storm surge barriers, pumping stations, etc.) Also high grounds protect against floods and can be part of dike rings, but these are generally not considered to be flood defences or hydraulic structures. It should be noticed that the covering by water is caused by exceedance of normal conditions. The Dutch Technical Advisory Committee on Flood Defences (TAW) distinguishes five types of flood defences, regards their role in the flood control system: • primary flood defences • secondary flood defences • polder quays [boezemkaden] • quays in Limburg • small river quays Within the class of primary flood defences, the difference between the delta area with tidal influences and the upper river areas plus the IJsselmeer has resulted in different legislative treatment. Secondary flood defences are chiefly situated in dike rings along the coast. Quays in Limburg haven been con- structed after the high water in the Maas river in 1995. Small river quays are mainly situated in the dike ring areas of the upper rivers. TAW/ENW made a classification, distinguishing function, location, type and threat per flood defence class, see table 1.1. This classification is relevant regarding the loads acting on the flood defence, and therefore has consequences for their shape. 1This definition is based on (Collins World English Dictionary, 2012), (European Commission, 2007) and (Website USACE, Coastal & Hydraulic Laboratory, 2012). 1 2 1.I NTRODUCTION Table 1.1: Classification of flood defences based on their role in the flood control system 1.2.A FLOOD DEFENCE STRUCTURE AS PART OF A SYSTEM 3 1.2. A FLOOD DEFENCE STRUCTURE AS PART OF A SYSTEM It should be noticed that to provide actual protection against floods, a flood defence has to be part of a complete system. This system comprises an actual and an abstract part. The actual system consists of a continuous protective line around the area that has to be protected, like a dike ring, eventually combined with high grounds. The abstract system consists of the organisation of the operation and maintenance of the concrete part. Also the settling of safety levels and assessment methods belongs to the abstract system. 1.3. THE DIFFERENCE BETWEEN A FLOOD DEFENCE STRUCTURE AND A WATER RETAINING WALL According to the definition given before, a flood defence protects land from flooding. According to (Collins World English Dictionary, 2012), ’land’ refers to the solid part of the surface of the earth as distinct from seas, lakes, etc. and also to ground, esp with reference to its use, quality, etc. ’Ground’ is defined as the land surface; earth or soil. This implies that, for example, an ordinary car park ’in the open air’ temporarily covered with water, is considered to be ’flooded’, but if only a structure is temporarily filled with water (say, the cellar of a house is filled with water due to an extremely high water level of an adjoining river), it is not ’flooded’ according to this definition. To formulate the difference in other words: a flood defence is part of the first layer of the Dutch multi-layered flood defence approach (Ministerie van Verkeer en Waterstaat, 2009), which is the flood prevention layer. If a house is made watertight only to protect the furniture and belongings of its inhabitants, but not to protect the hinterland, the water retaining walls of this house are not called ’flood defences’. This kind of measures belongs to the second layer of the multi-layered safety approach. The second layer is not intended to prevent floods, but aims to reduce damage and loss of life in case of an eventual flood. So only if water retaining walls are part of the first layer of the multi-layered safety approach, they can be described as flood defences. 1.4. MULTIFUNCTIONALITY:INTEGRATION OF FUNCTIONS 1.4.1. SECONDARY FUNCTIONS The most common reasons to combine functions with flood protection are summarized in the follow- ing list: • necessary improvements of existing flood defences conflict with other functions (housing) • ongoing urbanisation requires additional space • public funding under pressure (economic crisis) • changed societal and political attitude Improvement of existing flood defences (the first item of the list above) can be necessary because of: • increased flood risk: 4 1.I NTRODUCTION – expected increase of water levels / river discharges – increased economic activity – increased population – decreased risk acceptance • scheduled maintenance • preventive maintenance (failed assessment round) • repair A not exhaustive list of secondary functions is given in the following list SECONDARY FUNCTIONS FULFILLED BY HYDRAULIC STRUCTURES • providing through-passage for shipping (navigation lock) • providing through-passage for pedestrians, motorised and non-motorised vehicles (cut-off, gate) • enabling berthing and (un)loading of ship (quay wall) SECONDARY FUNCTIONS FULFILLED BY CIVIL STRUCTURES, NOT BEING HYDRAULIC STRUCTURES • transport fresh or waste water (sewerage) • transport of vehicles (roadway, railway, tramway, cycle path or pedestrian path) • transport of natural liquid gas (through pipe) • transport of electricity for power supply (cable) • transport of data (copper or fibreglass cable)