RETROFITTING EXISTING HOUSES IN BIERENS DE HAAN, AMSTERDAM POSSIBILITIES FOR IMPLEMENTING RAINWATER RETENTION MEASURES IN A GREEN DEAL COLLABORATION

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1 RETROFITTING EXISTING HOUSES IN BIERENS DE HAAN, AMSTERDAM POSSIBILITIES FOR IMPLEMENTING RAINWATER RETENTION MEASURES IN A GREEN DEAL COLLABORATION

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3 RETROFITTING EXISTING HOUSES IN BIERENS DE HAAN, AMSTERDAM POSSIBILITIES FOR IMPLEMENTING RAINWATER RETENTION MEASURES IN A GREEN DEAL COLLABORATION Master Sustainable Development GEO Transdisciplinary Case Study Utrecht University Client: Supervisors: S. van Odijk (Waternet) dr. P.P. Schot dr. ir. W.H.J. Graus dr. F.S.J. van Laerhoven Ties Corten ( ) Global Change and Ecosystems Thomas Kraaijenbrink ( ) Global Change and Ecosystems Sandra van Soelen ( ) International Development Paulien Hoogvorst ( ) Energy and Resources Niek Willemsen ( ) Energy and Resources Lisanne Mulders ( ) Energy and Resources Lavinda Kok ( ) Environmental Governance 2

4 SUMMARY This paper identifies opportunities for Waternet (and other stakeholders) to implement rainwater retention options in the Bierens de Haan neighbourhood in Amsterdam Nieuw-West. Waternet joined an existing Green Deal which tries to improve the energy efficiency in the neighbourhood and Waternet is trying to identify a way in which they can help improving the (water) efficiency. For Waternet measures for rainwater retention are researched, since rainwater can cause problems due to future climate change. Several technologies are researched, which could be implemented in the Bierens de Haan neighbourhood. However, the Green Deal collaboration will make or break the implementation of the rainwater retention measures. The neighbourhood is selected by Ymere, who coordinates this Green Deal collaboration. The Green Deal can be used for implementing rainwater retention options. Before the technologies are assessed, the status of the collaboration is investigated. From the analysis it appeared that the Green Deal is a good attempt to work together with different parties on a specific topic. However, the analysis also showed some struggles, which are common for working with different organisations. The different technologies that can be applied in the Bierens de Haan neighbourhood are scored on sustainability criteria. The technological analysis concludes that it is possible to retain all rainwater that falls in the area, in case of a rain intensity that only happens once in two years, by combining several of the examined technologies. However, different technologies compete in the same catchment area, for example the green roof and water retention bag both retain water from the roof. Therefore they should not all be implemented next to each other. Combining the insights from both the collaboration and the technological perspective, two different scenarios are presented. One is a scenario that best fits within the current Green Deal collaboration. The residents should get an extra option to the existing package which includes the water retention bag, which has the possibility of reusing the rainwater in house. Waternet needs Ymere and ASW for implementing this scenario. However, the residents are most important, since the water bag has to be implemented and used in their house. The second scenario is more ambitious and demands more dedication from the consortium partners. The goal is to retain all rainwater in the neighbourhood, therefore no rainwater drainage is needed anymore. This scenario includes the same water bag as the first scenario, but also two rainwater retention options that need to be implemented in public area of Bierens de Haan. These two options include adding more green to the neighbourhood and making use of diffuse infiltration systems, which are porous roads and pavements. To conclude; there are several ways for Waternet to effectively join the Green Deal collaboration, but they first need to identify what they want and how much they are willing to invest in order to make a real contribution to the Bierens de Haan neighbourhood. All partners in the GD are motivated to work together and make this collaboration a success, but a real structure is needed to achieve the best possible options. 3

5 SAMENVATTING Dit onderzoek onderzoekt de mogelijkheden voor Waternet (en andere stakeholders) om regenwater maatregelen in de Bierens de Haan wijk in Amsterdam Nieuw-West te implementeren. Waternet is recentelijk bij een bestaande Green Deal aangeschoven. Deze Green Deal samenwerking kijkt naar de mogelijkheden om de energie-efficiëntie in de buurt te verbeteren. Waternet probeert een manier te vinden waarop de waterefficiëntie ook verbeterd zou kunnen worden. Er zijn maatregelen onderzocht die van toepassing zijn op het afvangen van regenwater, omdat regenwater kan leiden tot problemen door klimaatveranderingen. Verschillende technologieën worden onderzocht die geïmplementeerd zouden kunnen worden in de Bierens de Haan buurt, maar de implementatie van de maatregelen valt of staat bij de gehele Green Deal samenwerking. De buurt is geselecteerd door Ymere en zij coördineren de Green Deal samenwerking ook. De Green Deal kan worden gebruikt voor de invoering van de regenwater retentie mogelijkheden. Voordat de technologieën kunnen worden beoordeeld, wordt de status van de samenwerking toegelicht. Uit de analyse blijkt dat dat de Green Deal een goede poging is om samen te werken met verschillende partijen die hetzelfde doel voor ogen hebben. Echter, de analyse geeft ook aan dat er aantal lastige kwesties zijn die altijd voorkomen als er op dergelijke schaal wordt samengewerkt. De verschillende technologieën die kunnen worden geïmplementeerd in de Bierens de Haan buurt, worden gescoord op een aantal duurzaamheidscriteria. Met behulp van deze technologieën is het mogelijk om al het regenwater dat valt op te vangen, zelfs bij een bui die slechts eenmaal in de twee jaar valt. Dan zouden een aantal technologieën gecombineerd moeten worden, maar dat is niet altijd haalbaar in verband met een concurrerende opvang techniek. Zoals bijvoorbeeld het geval is bij het groene dak en de waterzak. Als het water wordt vastgehouden op het dak, is er niet voldoende input voor de waterzak. Mede daardoor is het niet mogelijk alle technologieën naast elkaar uit te voeren. Het combineren van de inzichten uit zowel het functioneren van de samenwerking als het technologische mogelijkheden hebben geresulteerd in twee scenario s. Het eerste scenario omvat de waterzak. De waterzak vangt regenwater op vanuit de dakgoot en wordt in huis gebruikt om te wassen en de toilet door te spoelen. Deze optie kan worden toegevoegd aan de reeds bestaande optiepakketten die worden aangeboden door Ymere aan de bewoners. Het tweede scenario is ambitieuzer en is gericht op 100% regenwater retentie in de wijk, zodat hemelwaterafvoer niet meer nodig is. Dit scenario omvat ook de waterzak, maar daarnaast ook twee opties die in de openbare ruimte van Bierens de Haan moeten worden geplaats. Het gaat hierbij om een aantal verzonken, groene parkjes en een diffuus infiltratiesysteem dat volledig is geïntegreerd in de weg en stoep. Tenslotte zijn er verschillende mogelijkheden voor Waternet om effectief samen te werken binnen de Green Deal, maar dan is het wel belangrijk dat hun eigen visie eerst goed duidelijk is. Daarnaast is het ook belangrijk te identificeren hoeveel geld er beschikbaar is om te investeren in deze wijk of dit project. Alle Green Deal partners zijn gemotiveerd om samen te werken aan dit project en het succesvol af te ronden. Maar voordat dat kan gebeuren is eerst een duidelijke structuur nodig. 4

6 PREFACE During the course Transdisciplinary Case Study at Utrecht University, a team of seven Sustainable Development students, all with different backgrounds, worked together on a project that was initiated by Waternet. Waternet is an organisation in Amsterdam that provides the inhabitants with drinking water, but is also responsible for the retention and discharge of rainwater. The project Waternet had decided upon for us was concerning a recently joined Green Deal collaboration in the Bierens the Haan neighbourhood in the Nieuw- West district of Amsterdam. The research project became more tangible after we visited the neighbourhood on September 13th. From that point onwards, the research project began to take form. Waternet is searching for a way to participate in the Green Deal in Bierens de Haan and our reseach is focussed on finding a way for them to join. We decided upon a role for Waternet in the Green Deal consortium with rainwater retention options. Different technologies are assessed in order to check whether the options are viable for the neighbourhood. We would like to thank Sanderine van Odijk from Waternet for her input and support during our research. Also Paul Schot from Utrecht University for his feedback and his trust in our final product. Frank van Laerhoven and Wina Graus contributed with their written feedback on both draft versions. Also very important for the creation of our paper were the interviews we conducted with the inhabitants of the Bierens de Haan neighbourhood on October 3th, Marc van Arem from Ymere, Erik de Bruijne from Waternet, Joost Jacobi from H2mOtion, Remko Cremers from Liander. Eef Meijerman and Henk Lalji from ASW, and Marije van Donselaar van Nuon and Erik Theissing from district Nieuw-West. Within the student team several backgrounds are present and therefore the tasks are divided into more or less disciplinary chapters. The chapters 1,2 7 and 8 have an integrative character and are written by all students together. The grading depends on the division of chapters. Table 1, The division of disciplinarychapters per person. Student Disciplinary chapter Ties Corten chapter 5 + chapter 6 Thomas Kraaijenbrink chapter 3 + chapter 5 Sandra van Soelen chapter 4 Paulien Hoogvorst chapter 6 Niek Willemsen chapter 6 Lisanne Mulders chapter 6 Lavinda Kok chapter 4 5

7 TABLE OF CONTENTS 1. INTRODUCTION APPROACH INTRODUCTION A MULTI-DISCIPLINARY RESEARCH STRATEGY METHODOLOGICAL STEP AND DATA GATHERING CASE DESCRIPTION / BIERENS DE HAAN NEIGHBOURHOOD [THOMAS] INTRODUCTION CURRENT AND FUTURE CLIMATE POLICY CONTEXT NEIGHBOURHOOD CHARACTERISTICS ASSESSMENT OF COLLABORATION [SANDRA AND LAVINDA] INTRODUCTION FACTORS DETERMINING COLLABORATION ANALYSIS: STRENGTH AND WEAKNESSES OF THE CONSORTIUM CONCLUSION AND RECOMMENDATIONS SUSTAINABLE RENOVATION CRITERIA [THOMAS AND TIES] INTRODUCTION CRITERIA ASSESSMENT OF TECHNOLOGIES [TIES, NIEK, LISANNE AND PAULIEN] INTRODUCTION GREEN ROOFS STORAGE AND REUSE OF PRECIPITATION IN HOUSE A LOW LYING PUBLIC GREEN SPACE THAT DOUBLES AS A STORAGE POND INFILTRATION SYSTEMS CONCLUSION SCENARIOS FOR RAINWATER RETENTION INTRODUCTION EASY FIT IN GREEN DEAL RENOVATION STRUCTURE AMBITIOUS SCENARIO: 100% RAINWATER RETENTION CONCLUSION AND RECOMMENDATIONS DISCUSSION REFERENCES APPENDIX APPENDIX I: DATES AND TOPIC LIST INTERVIEWS GREEN DEAL STAKEHOLDERS APPENDIX II: QUESTIONNAIRE FOR RESIDENTS APPENDIX III: INTERVIEWS GREEN DEAL STAKEHOLDERS APPENDIX IV: INTERVIEWS WITH THE INHABITANTS OF THE BIERENS DE HAAN NEIGHBOURHOOD

8 1. INTRODUCTION Climate change may well be the biggest and most complex environment-related problem this century and beyond (Müller, 2002). It is a complex issue that has exercised the minds of experts and policy makers with renewed urgency in recent years. Although climate change is a natural phenomenon, anthropological actions also have a major influence. The emissions of greenhouse gases are causing the climate to change (Ibid). Although it is difficult to predict the consequences of the changing climate, it is assumed that it will lead to e.g. changing weather patterns (more heavy rain, more rain, more dry periods) (Rijksoverheid, 2012b). In order to overcome the complex challenges of climate change, collaboration of public and private organisations is needed. Multi-actor collaboration is useful for problems which affects numerous people, groups and organisations, to involve various actors in civil society, government and business to work together (Bryson, 2004). These partnerships can be seen as innovative forms of governance that can possibly address the deficits of environmental governance (Bäckstrand, 2006). When looking at water management, participation of stakeholders in the planning process is increasingly seen as an essential element (Lamer et al., 2010). Moreover, public participation is an essential factor in developing adaptive and integrated water management (Ibid). The Dutch government is promoting different collaboration initiatives to stimulate innovative cooperation to adapt to climate change. One of these initiatives is a Green Deal, an agreement between several public and/or private parties in order to bring a variety of stakeholders together (Rijksoverheid, 2012a). In Amsterdam Nieuw-West, a Green Deal is agreed for a sustainable renovation of 1500 houses (Visser, 2012). The aim in this particular Green Deal is to increase the implementation of diverse technologies that improves the sustainability of existing houses, particularly focused on energy savings. The representatives of the involved organisations work together in a consortium to develop the content of the Green Deal. Because of the economic crisis in Europe, the housing market has changed. Instead of a focus on the construction of new houses, the renovation of existing houses has become a focus point (Ymere, 2011). Waternet, a Dutch water board organisation, responsible for drinking-, rain- and wastewater management, discharge and treatment in the Amsterdam region, recently joined the Green Deal consortium. Waternet tries to develop a more sustainable and innovative way of water management (Personal communication S. van Odijk, 2012). Amsterdam is prone to extreme rainfall events and due to future climate change those events are expected to increase in both intensity and frequency (Van de Hurk et al., 2006; Allan and Soden, 2008). Extreme rainfall is now already leading to flooding of streets ad basements in the centre of Amsterdam, which is not good for the image of Waternet. Local solutions to retain or use rainwater will decline the need of more capacity of the sewage system, and thus can reduce major future investments in upgrading sewage systems. Waternet joined the consortium to stress the need for sustainable water management on local level. Waternet is currently developing its position and vision within the Green Deal. Rainwater retention is one of the opportunities for adaptation to climate change that could be part of that vision. Waternet is already engaged in such projects, and started themselves the project Amsterdam Rainproof (Waternet, 2012). Therefore, this research focuses on rainwater retention measures. At the same time, the research will look at the collaboration in the Green Deal at the moment. Within the Green Deal, 177 houses in the neighbourhood Bierens de Haan are on the agenda to be renovated. The aim of this research is to present Waternet with feasible technologies that can be implemented within the Green Deal in Bierens de Haan and to advise Waternet on how they should participate within the Green Deal. In this way, the research wants to give substance to the pilot and the required agreements between the stakeholders. The overarching research question is: 7

9 What are opportunities within the Green Deal for Waternet (and other stakeholders) to implement retention and reuse of rainwater technologies in Bierens de Haan? In order to answer the research question, the following four sub questions are formulated. What are the policy, climatic and physical background regarding water retention possibilities in Bierens De Haan? (chapter 3) What is the status of the collaboration process in the Green Deal and what are the opportunities to improve this process? (chapter 4) What criteria are needed to assess sustainable renovation techniques? (chapter 5) Which techniques are economically, technically and politically feasible in and around the existing houses to retain and/or reuse rainwater? (chapter 6) The questions guide towards finding opportunities within in Bierens de Haan. Also possible scenarios are constructed for Waternet that could help them envisioning and formulating their position in the Green Deal in Bierens de Haan. However, it is important to understand, that what can be learnt from this case, can be extended to future renovation projects or other Green Deal structures as well. The approach and methods of the research and the structure of this document are presented in chapter 2. 8

10 2. APPROACH 2.1 INTRODUCTION The aim of this research is to determine opportunities for Waternet and other stakeholders to invest in rainwater retention measures in Bierens de Haan. During this research it became apparent that the neighbourhood has currently no rainwater problems (and this is also not expected in the near future). Nevertheless, exploring the opportunities on technological and politically feasibility provide valuable insights for Waternet. What can be learnt here might also be applicable for other renovation initiatives in Amsterdam, or even the Netherlands. This research is therefore of exploratory nature where Waternet and the other stakeholders can learn (for this case and for future collaboration). A multi-disciplinary and qualitative approach is at the basis of this research, which will be more explained in the remainder of this chapter. Section 2.2 elaborates on the different multi-disciplinary paths towards the aim of this research. After that, in section 2.3, the methodological steps (including data gathering) of each chapter are described. 2.2 A MULTI-DISCIPLINARY RESEARCH STRATEGY The sub questions, formulated in the introduction, guide towards four different disciplinary chapters; Case description, Assessment of collaboration, Sustainable renovation criteria and Assessment of technologies. These chapters form the basis for creating two scenarios for Waternet and the final integration chapter. An overview of the structure is given in figure 2.1, and will be further explained in the following paragraphs. First, it is important to understand the background of the Bierens de Haan neighbourhood (like the infrastructure and the people who live in it) and relevant policies. Also possible (future) problems regarding rainwater retention in the area are shown by information on the current and future precipitation in the area. This background, discussed in chapter 3, provides information relevant for the following steps of the research. From that point onwards, two paths are taken to identify opportunities for Waternet and other stakeholders. In order to identify opportunities for rainwater retention through this Green Deal, it is necessary to understand the collaboration process. The first path concerns therefore the collaboration process of Waternet and other stakeholders. Research shows that when the decision-making process of multi-stakeholder collaboration is more successful, the implementation of decisions is likely to be better and better sustainability results and outcomes are achieved (e.g. Jackobson and Choi, 2008; Newig and Fritsch, 2009). It seems that successful collaboration is at the root of successful decisions, hence an exploratory evaluation is given on the current process and output 1 from a social interactive approach on the multi-actor collaboration process. A social interactive approach considers that decision-making processes and results are caused by the interplay of several stakeholders (Runhaar and Corvers, 2008). The result of this chapter will provide strengths and weaknesses of the current collaboration, and recommendations (for Waternet, but also for the other stakeholders) to improve the success of the collaboration. This path is in figure 2.1 represented by the green arrow. The second path (corresponding with the blue arrows in figure 2.1) focuses on possible rainwater retention technologies. The technologies are chosen in consultation with the client and expert interviews. An analytical rational approach (based on rational arguments, science) is taken to assess the feasibility of the technologies: the first step of this path is the construction of sustainability criteria (chapter 5), which is followed by an 1 The focus on is on the collaboration itself, because the Green Deal in Bierens de Haan is still rather young (3 years): it is to early to consider the outcomes and impacts. 9

11 assessment of the technologies (chapter 6). Rainwater retention technologies on different scales are examined on their usefulness for water storage in the Bierens de Haan neighbourhood. In order to compare the technologies, a set of criteria is used. Furthermore, the technologies are assessed on acceptance by the inhabitants. Chapter 6 will result in a scheme identifying strengths and weaknesses of the different technologies, that enable (preliminary) comparison. Figure 2.1 Flowchart of relation between different chapters In chapter 7, both paths (collaboration process and technological feasibility) are integrated, and at request of Waternet, two scenarios on water retention in the area are described. The first scenario is constructed on the basis of what is best suited in the current Green Deal structure and the second scenario concerns the highest amount of water retention possible. In chapter 8 follows a final conclusion on the identification of opportunities for Waternet and their partners in the Green Deal on how to make best use of the possibilities to improve the retention and reuse of rainwater in Bierens de Haan. The opportunities will not only lead to recommendations for this specific case, but also for other collaborative renovation projects. 10

12 2.3 METHODOLOGICAL STEP AND DATA GATHERING In the following sections methodological steps of the disciplinary chapters are further explained. Case Description (chapter 3) In this chapter a literature review is conducted to gather the required data. Data on current and future precipitation and corresponding data is gathered through literature studies, and precipitation data from the KNMI (the Royal Dutch Meteorological Institute). Furthermore, insights in the policy regulations and landscape is needed. This is researched by reading policy documents on national, regional and local scale. Here factors that provide opportunities and threats are gathered (policy in the Netherlands, Amsterdam and Nieuw-West). Also, characteristics of the neighbourhood Bierens de Haan are necessary for further investigation of the technologies. This will include characteristics like the number of residents, etc. This information is retrieved from Ymere, interviews in the neighbourhood and Geographic Information System (GIS). Assessment of collaboration (chapter 4) Within this chapter a few methodological steps are taken. The first step is a literature review in order to identify relevant factors that contribute to the success of multi-actor collaborations. In the search engines Google Scholar and Scopus search words were entered (in different combinations): multi actor, stakeholder, collaboration, governance, public private governance arrangements, sustainable renovation, urban water management, effectiveness, success. Also the reference lists of the found articles were scanned for selecting appropriate articles. From the articles factors were extracted leading to a conceptual model that identifies conditions that are needed for successful collaboration. The conceptual model is at the basis for the analysis of the collaboration process. Before the analysis can be done, data is needed on collaboration within the Green Deal. There are two data sources: (1) the stakeholders that represent the organisations in the consortium and (2) documentation (e.g. policy documents, project plans, websites) of the different organisations they represent. The latter source semi-structured interviews with stakeholders of the Green Deal are conducted. The aim of the interviews is to get insight on the interests and goals and they can give their opinion about the situation. Themes of the conceptual model are central subjects and questions of the interviews. A topic list is given in appendix I. When data was incomplete, the respective respondent is contacted (by phone or mail) for gathering the missing information. If the latter was the case they are consulted as experts for the governance and policy aspects as well. For feasibility reasons, not all Green Deal stakeholders are consulted. In consultation with Waternet the following consortium members are interviewed: Erik Theijsing (Stadsdeel Nieuw-West), Marc van Arem (projectleader, Ymere), Remko Cremer (Liander), Eef Meijerman and Henk Lalji (ASW), Marije van Donselaar (Nuon), Sanderine van Odijk (Waternet). They were regarded as core stakeholders in the collaboration process. All stakeholders were interviewed face-to-face, except for Marije van Donselaar, with whom a telephone interview was conducted. The aim was also to interview Thomas de Jong from AgentschapNL, however he was not available during the time period of this project. AgentschapNL is the supporter and funder of the project, and could have provided valuable information about the progress. Data from the AgentschapNL is included via official documents, which are retrieved from Internet. Sustainable renovation criteria (chapter 5) Rainwater retention technologies on different scales are examined on their usefulness for waterstorage in the Bierens de Haan neighbourhood. In order to compare the technologies, a set of criteria is used. These criteria 11

13 are selected based on a literature study and include economical benefits and costs, water retention ability and local residents in order to show different benefits and disadvantages for the stakeholders per technology. Assessment of technologies (chapter 6) As mentioned previously, the technologies for water retention are chosen together with the client (Personal communication S. van Odijk, 2012). Interesting for the client is to choose technologies that can be implemented in or around the house and in the public area. The traditional role of Waternet ends at when the water enters the house. However, this time the potential measures are not limited to outdoor measures as they are now part of a renovation consortium. The measures in and around the house include the waterbarrel, water tank and green roof. For the public area the technologies are water parks, diffuse and central infiltration systems. Based on the sustainability criteria (chapter 5), the technologies are assessed. The data is gathered by literature study and by document reviews of similar cases. Next to this, specific local knowledge is gathered by conducting interviews with stakeholders, like Waternet experts, Ymere employees and residents. The interviews are semi-structured and the list of questions used for the interviews can be found in appendix II. By these interviews, the social acceptance for the technologies is evaluated and the findings of the residents about the renovation so far are listed. The interviews in the neighbourhood give an understanding on the background of the residents, how they live, what their experiences are regarding (upcoming) renovation of their houses and on the acceptance of rainwater retention measures. The construction and the execution of the interviews is supported by methodological literature (e.g. KU Leuven, 2006; Verschuren and Doorewaard, 2010). The question list is used as a guidance. The project group went to the neighbourhood on the third of October. In total 20 household interviews were conducted. Beforehand sixty households were randomly selected to be part of this study. Forty households were not at home, did not open the door or did not want to cooperate. This was done by randomly picking of one of the eight streets and a house number. In case the door was not opened, the bell of the house at the left was tried. In what way each chapter uses the interviews, is further explained in the following sections. 12

14 3. CASE DESCRIPTION / BIERENS DE HAAN NEIGHBOURHOOD [THOMAS] 3.1 INTRODUCTION In order to study the possibilities for effectiveness of rainwater retention systems in the Bierens de Haan project area, background information of the area itself is needed. Firstly, the trends in precipitation for the Netherlands and subsequently Amsterdam can indicate whether certain rainwater retention solutions will be sufficient to maintain a safe environment in the future. Secondly, the policies influencing the opportunities for implementation are of importance when a renovation project is conducted. Lastly, some characteristics of the researched neighbourhood are important, especially considering the fact that some of the technologies need sufficient surface area, but also sufficient support of the inhabitants. 3.2 CURRENT AND FUTURE CLIMATE Current precipitation In Amsterdam, rainwater is discharged through a canal system directed toward the North Sea, where a discharge station is located near IJmuiden. The discharge actually functions by using water from the IJ, and flushing the canals of the city at North Sea low tide (Koeze and Van Drimmelen, 2009). In the present situation, there is enough discharge potential in most of the city, although the centre of Amsterdam does have some areas which can barely cope with heavy rains, resulting in road and basement flooding from time to time (Nu.nl, 2012). Due to the change in amount of precipitation in the last century, those heavy rainfalls occur more often than they did decades ago (Fig 3.1). Especially in the Amsterdam region, the increase in average rainfall has been large (Fig 3.2) (Van Boxel and Cammeraat, 1999). Although the target neighbourhood did not experience severe flooding issues in recent times, heavy rains could induce floating of garden tiles, and gardens and roads did stay flooded for some time (Personal communication with residents). Figure 3.1, Precipitation change (Van Boxel and Cammeraat, 1999) 13

15 Figure 3.2, Precipitation amount in the Netherlands per region. (Van Boxel and Cammeraat, 1999) Another important aspect are the potential dry periods in summer. In prolonged dry periods, the discharge system from the IJ through the city towards the North Sea is reversed at North Sea high tide. This is increasing salinity in inland waters, and stopping discharge capacity completely (Koeze and Van Drimmelen, 2009). Furthermore, dry periods might increase stress on clean drinking water systems. In Amsterdam, drinking water is provided by both treated water from the IJ, and water distracted from the dunes, but as said before, waterflow from the IJ toward the city is limited during dry periods. In this case, water is imported trough the Lek river. This is however a very expensive measure, thus drinking water savings on a household level during dry periods is a method to postpone those measures (Koeze and Van Drimmelen, 2009). Future precipitation Although the city of Amsterdam does not have major water related issues yet, there have been some problems regarding minor flooding, flushing of the canals, and clean drinking water stress. As awareness for climate related changes in water fluxes increases, more modeling studies become available. For example, the Dutch Meteorological Institute (KNMI) has modeled precipitation change for four different climate scenarios for the Netherlands (Van de Hurk et al., 2006). Those scenarios are based on both the temperature increase until 2100 AD, and the possible change in air circulation due to this temperature change. The outcome can be seen in figure 3.3. Two different temperature changes have been modeled, and for each temperature change the precipitation patterns with and without air circulation change is modeled. All scenarios show an increase in winter precipitation, and a decrease in summer precipitation when considering air circulation changes. This means that both flooding potential in winter, and drought thus clean water stress in summer will increase further in Amsterdam, and in the Bierens de Haan neighbourhood as well. Also, the aforementioned discharge problems in periods of draught will be more frequent. Furthermore, it should be noted that flooding risk in Amsterdam mainly occurs in extreme rainfall events, as discharge and sewage systems in Amsterdam are capable of handling regular rainfall patterns, yet heavy rainfall events seem difficult to cope with (Koeze & van Drimmelen, 2009). According to Lenderink et al. (2011), those extreme rainfall events will occur more often as well, therefore increasing flooding risk and the need for adaptations. No initiatives concerning water reuse and retainment facilities are yet included within renovation programs in Amsterdam Nieuw-West. The current renovation plans include the improvement of isolation as a first step. The applied energetic measures are double glazing and facade, and roof isolation. The second step is to produce the energy needed in a sustainable way. The intention is that all houses are to be connected to district heating and fitted with solar panels (Visser, 2012). 14

16 Figure 3.3, Showing changes in precipitation in the Netherlands, while considering different future climate scenarios (Van der Hurk et al, 2006) Waternet wants to make an addition to the project by including water in the project in addition to just energy. One of the core ambitions is to connect and bridge the interests of many different stakeholders in the field towards more sustainable existing housing stocks. Although there are many technologies available, the different parties such as installing parties, suppliers and citizens rarely come to agreements and realization. This report will advise on the possible technologies concerning rainwater reuse and retention technologies, while considering several aspects regarding implementation of the technologies. Specifically the technological aspects, the governance involved and the costs and benefits of the technologies. This will be done using a criteria approach, comparing several rainwater specific solutions, and picking the most feasible ones. 3.3 POLICY CONTEXT Different policies play a role in the renovation project in Bierens de Haan. The most influential policies on national and local level are described below. National policies Blok voor Blok is a programme of AgentschapNL, focussing on large scale energy savings in existing houses. In a Blok voor Blok strategy of renovating houses, different parties (e.g. commercial parties, local government institutions and housing corporations) work together on a plan to renovate houses with a particular focus on energy savings (AgentschapNL, 2012). In a project, at least three commercial parties work together in a consortium with public organisations and other relevant stakeholders. The goal is to renovate houses sustainably, exchange knowledge between different parties and ultimately develop a national strategy for renovating existing houses (Ibid). The projects get a subsidy, but only to support the pilot phase of the project. Commercial parties also need to invest in the projects. 15

17 The Blok voor Blok renovation project in Bierens de Haan neighbourhood is called: Ymere Green Deal renovate existing houses fast and sustainable (Snel verduurzamen in de bewoonde staat). The objective of the project is to develop a smart renovation model to use for different house types which takes the participation of residents into account (AgentschapNL, 2012). The goal of the project is to renovate a block of houses fast and sustainable within a period of 4 months, with a maximum of 5 days without the residents in the houses and with a result of 45% energy savings (Ibid). If the model is successful, it can be used for other renovation projects of Ymere. The Green Deal policy is a central item in this project. As explained in the introduction, different stakeholders are involved in the Green Deal and are mostly concerned with achieving better energy performances in the existing houses. The government is supporting the Green Deals with money, accessing knowledge or simplifying rules and regulations (Rijksoverheid, 2012a). The different stakeholders involved in the Green Deal are working together in a consortium, which has regular meetings. The members of the consortium are Ymere, Amsterdamse Federatie van Woningcorporaties, Stadsdeel Nieuw-West, Liander, Nuon, Programma Slim & Snel, stichting Woonbond, Amsterdams Steunpunt Wonen (ASW), en Waternet (Ymere et al., 2011). In this paper, this project will be called Green Deal, to avoid misunderstandings. The Dutch government has also developed the National Adaptation Strategy; this strategy describes that climate change should be an integral part of the local policies. The strategy has attention for the societal consequences of climate change, wants to reduce negative impacts and wants to use opportunities (Stadsdeel Nieuw-West, 2011). The national adaptation agenda has three main goals: Prevent social disruption caused by climate change. Dealing with adverse effects of climate change. Exploiting opportunities of climate change and adaptation measures (Ibid). Local policies On local level, there are different policies or strategies relevant for the renovation process in the Bierens de Haan neighbourhood. Waternet has developed a stormwater handbook for the Waterboard and the municipality of Amsterdam. In this handbook, the knowledge about the handling of storm water is combined with the new water laws and regulations in the Netherlands and is a tool for the municipality. In this regard, an integral strategy is needed (Waterschap AVG, 2009). Moreover, there is an ambition of Waternet and the municipality of Amsterdam to make Amsterdam waterproof. District Nieuw-West is currently designing a new Waterplan, which will be focused on ensuring a comfortable living environment with a focus on sustainability and climate resilient policies. The goal is to develop a broad vision on water, with a focus on the cooperation between Waternet, the Waterboard, the municipality of Amsterdam and the district of Nieuw-West (Stadsdeel Nieuw-West, 2011). Furthermore, the district has developed an ambitious strategy for climate adaptation. The end goal of the strategy is to realize a climate resilient district, not by focusing only on the environmental aspects, but also in involving the social aspects (Ibid). The ambition related to water is a delayed drainage of rainwater (in the streets and from buildings) and retain as much as possible locally. This retained water can be stored or re-used locally (Ibid). Waternet is involved in the realisation of this ambition. 16

18 3.4 NEIGHBOURHOOD CHARACTERISTICS In order to give any advice about possible measures considering water cycles in the area, some characteristics of the neighbourhood are important. Firstly, the surface area of the neighbourhood can determine the possibilities and the extent of rainwater retention techniques. The surface area, soil composition and elevation also determine the vulnerability of the area to increased rainfall and to extreme rainfall events. Furthermore, the inhabitants play a major role in the success of implementation of certain measures, as they might or might not reject the proposed solutions, and thus make implementation very difficult. Housing corporation Ymere plans to renovate 1500 homes in the districts Amsterdam Nieuw-West and West. The goal of the renovation is improving the energy labels of housing from F/G to minimum energy label A. The renovation of 177 houses in Bierens de Haan is the first pilot project and the focus of this research. In the renovation, Ymere gives the residents the opportunity to include more measures than the mandatory isolation, to increase the livability of the house. The other options, like a dormer (dakkapel) or a garden shed can be chosen from a list of different packages. The neighbourhood consists of low rise row houses. Most houses have a small front and back yard. In between the houses are public areas, consisting of either grass or paved surface (including playgrounds) (Fig 3.4). Figure 3.4 A map of the neigbourhood showing houses, communal space, roads and pathways (Ymere, 2011) The neighbourhood has an average elevation level of 0.8 m below NAP (Nieuw Amsterdams Peil), while being surrounded by slightly higher areas as for example the northern end of park Slotermeer. Furthermore, most of the soil consists of peat, clay and sand, with a top layer of about 1.5 meters of sand (Grondslag BV, 2010). Although water infiltrates easily in sand deposits, peat and clay deposits are infiltrated much more difficult. Therefore, the area is serviced by a water pumping station in order to keep water levels low enough to prevent flooding. The water discharge system is connected by a separate sewer system and small channels to the Amstel, and is discharged in the North Sea (Koeze and Van Drimmelen, 2009). 17

19 The residents of the area are of a relative high age, which averages at 62 (Fig 3.5). The social status of the neighbourhood is fairly low, and recently an influx of inhabitants with low social status is occurring (Ymere, 2011). Also, there is little coherence between the inhabitants, as they originate from different areas in the Netherlands, and this causes division between them (Personal communication with residents). Figure 3.5. The age distribution of the residents in the Bierens de Haan neighbourhood (Ymere, 2011) 18

20 4. ASSESSMENT OF COLLABORATION [SANDRA AND LAVINDA] 4.1. INTRODUCTION As mentioned in the general introduction, the involvement of different parties within the Green Deal is an innovative approach on governing the process to renovate houses sustainably (Rijksoverheid, 2012a). Including more actors in policy-making is considered to be a response to ineffective central (environmental) policies in western democracies (Driessen et al., 2012; Newig and Fritsch, 2009). It is argued that the inclusion of more actors and participation will improve the effectiveness of policies (outcome and impact). The Dutch government also stimulates multi-actor collaborations, in order to improve the effectiveness of its policies (Priemus, 2004, p.202). Supported by AgentschapNL, various stakeholders work together in a consortium to improve the quality and energy saving capacity of existing houses (AgentschapNL, 2012). However, the argument that collaborations are more effective is not unambiguous: there are indications that decisions-making will occur less efficient, or the policy-measures are not ambitious enough (Newig and Fritsch, 2009). Furthermore, processes of decisionmaking with several stakeholders is regarded to be more complex (Klijn et al., 2010). It seems that a good collaboration process can be regarded as a prerequisite for successful decision making and implementation of policy measures (Jackobson and Choi, 2008). Therefore, before going into the technological aspects of mitigation and adaptation opportunities, first the collaboration process of this project will be analysed. The aim of this chapter is to understand the status of the decision-making processes and which factors are opportunities or threats for the effectiveness of the collaboration. The research question is: What is the status of the collaboration process in the Green Deal and what are the opportunities to improve this process? In order to answer this question first a framework of factors that influence the success of the process is discussed 2 (section 4.2). Empirical studies provide several insights on factors determining effective collaboration within multi-actor governance arrangements. Here four factors are constructed. Each of the factors is operationalised by means of three indicators 3. Although it is aimed to be as inclusive as possible the list of factors is not meant to be exhaustive. These factors will be used to analyse the situation in the Green Deal (section 4.3), but it is not the aim to discuss whether the Green Deal is the right tool to tackle this problem. After all the starting point is the presence of the Green Deal. Here the focus is on identifying opportunities and threats within the collaboration. The legitimacy and accountability are not at the focus of this research. We took a general approach (not the perspective of only Waternet), in order to get full understanding of the dynamics of the Green Deal. We do not consider the non-stakeholders i.e. the citizens of the area. This chapter ends with a conclusion in section See chapter 2 for full explanation of the methodology. 3 Different factors may be interrelated. The clustering in factors is a means to practically deal with the many indicators. 19

21 4.2 FACTORS DETERMINING COLLABORATION Willingness and ability to collaborate Successful collaboration is firstly determined by whether actors are willing and able to collaborate (Jackobson and Choi, 2008). Four indicators can be distinguished that specify the willingness and ability: interdependency, (organisational, social, cognitive and cultural) distance, commitment and influence. First, a collaboration in a multi-actor governance arrangement only makes sense when the actors are interdependent (Klijn et al., 2010; Newig and Fritsch, 2009). Having complementary knowledge or experiences will bring collaboration outcomes to a higher level and will be reached more efficiently 4 (Edelenbos and Teisman, 2008). On the other hand, organisational literature shows that the gap between culture, knowledge and experience from different actors should not be to wide, because otherwise the actors may not understand each other (Boschma, 2005). Priemus (2004) argues that different stakeholders are often unaware of the underlying different interpretations of the problems and actions, which inhibits successful collaboration. It is therefore necessary to understand and learn about each other, organisational structures, knowledge processes and culture. Furthermore, commitment in combination with the influence of the stakeholders is an indicator for success (Jackobson and Choi, 2008; Newig and Fritsch, 2009). Jackobson and Choi (2008) show that when actors show effort to understand each other and take into account each other s needs, collaboration is more likely to be successful. Commitment is here operationalised as the commitment perceived by the other stakeholders. Furthermore, when an influential actor is committed, this can lead to an higher rate of the overall success 5 (Bryson, 2004; Jackobson and Choi, 2008). Towards shared visions A clear and shared vision is necessary in order to gain good performances of collaboration, because conflicting interest can delay decision-making, or make collaboration more difficult (Jackobson and Choi, 2008; Lamers et al., 2010). Three indicators are distinguished: transparency on individual goals and preferences, understanding each other s goals, and sharply defined shared vision. Stakeholders have goals and preferences of their own, which may be conflicting with the goals of others. At the same time they should work together in order to achieve mutual goals. Collaboration is influenced by the way actors deal with the tension of individual and mutual preferences and goals (Newig and Fritsch, 2009, p.205). First of all, stakeholders should be transparent on their preferences and goals (Jackobson and Choi, 2008; Newig and Fritsch, 2009). Secondly, understanding the preferences of others is at the base towards creating a shared vision. By trying to see commonalities instead of conflicting preferences, it is more likely to create a better shared vision. Otherwise a vision can be a inconsistent compromise instead of a collective optimal solutions (Gupta, et al., 2004; Newig and Fritsch, 2009, p.205; Priemus, 2004, p.202). According to Jackobson and Choi (2008) a vision should be as sharply defined as possible in which the boundaries are mutually set. Activities especially organised for envisioning (e.g. workshops or team-building linked to the project) can help 4 The transaction costs and overall costs are lower (Jackobson and Choi, 2008). 5 Note that here the power to press its own interest by the influential actor is not taken into account. It is purely about the commitment. 20

22 stakeholders to gain a shared vision: stakeholders get to know each other formally (with their role in the project) and informally (a drink after dinner) (Lamers et al., 2010). Creating a collaborative atmosphere In order to create a collaborative atmosphere, the indicators trust, open communication and team-building activities are important. Trust can be considered as a necessary condition for long term collaboration and exchange of knowledge and information between different stakeholders (Klijn et al., 2010; Henry and Dietz, 2011, p.189). Trust is defined as the absence of opportunistic behaviour and as a positive expectation that a stakeholder has (or predicts) of the intentions and motives of another stakeholder and the prediction that a stakeholder will behave cooperatively (Klijn et al., 2010). One assumes that stakeholders need to have some degree of trust that the others involved in their decision-making situation will also cooperate (Ibid). Stakeholders trusting each other can have positive outcomes; trust can results in reduction of transaction costs, increases the probability that stakeholders will invest their resources, stimulates learning and exchange of information, and can stimulate innovation (Ibid.). Open communication will increase trust (Jacobson and Choi, 2008). When there is open and transparent communication, different stakeholders are more likely to trust each other. Regular communication between the different stakeholders is needed by using effective, regular and varied communication channels (Jacobson and Choi, 2008). Formal and informal interactions can lead to the strengthening of trust between actors (Klijn et al., 2010). Often, a new multi-actor process means that different stakeholders work together that previously have little or no experience working together. Team-building activities can lead to more trust and better communication between the different stakeholders and studies have concluded that this can save money (van der Arend, 2007; Jackobson and Choi, 2008). Collaboration management Multi-actor collaboration needs effective management (Jackobson and Choi, 2008). The three indicators are: presence of strong leadership, clear roles and responsibilities and monitoring and adaptation. First, the process should be managed by experienced or qualified process leaders, which can enhance the successful outcome of the participatory process (Lamers et al., 2010). It is essential that someone has the overview of the process and knows what is going on. Furthermore, a leader is needed to initiate and facilitate interaction processes between the stakeholders involved. Interaction between actors can be formal and informal and can lead to trust (Klijn et al., 2010). A leader does not necessarily be directly involved in the process; there are experiences were an external leader has had a positive influence on the project s outcome (Lamers et al., 2010). Second, it should be clear which role and responsibilities each stakeholder has. This ensures that stakeholders are well aware of their tasks and know what is expected (Jackobson and Choi, 2008). Also the share of costs and benefits should be well defined (Edelenbos and Teisman, 2008). Third, having a collaboration network for a longer period of time, with intensive regular interactions between the different stakeholders, enables successful collaboration (Klijn et al., 2010). This is leading to continuity, which is enhanced by systematic monitoring of interactive processes, participation and a process leader (see above) (Lamers et al., 2010). Concerning systematic monitoring, formulating clear guidelines for the monitoring process are necessary (Bäckstrand, 2006). The intensive interaction, also stimulates learning and discovering new things. This is important to improve existing processes and for extenting pilot projects (Lamers et al., 2010). Reflexive 21

23 workshops during and after the process are needed to stimulate learning. Furthermore, it is important to have regular evaluations (when milestones are achieved) to ensure that improvements can be made at different times and to ensure a shared vision (Ibid). This also enables the collaboration to adapt to changes in the process. The different factors explained above are summarised the table 4.1. The next paragraph will analyse the different factors in the Green Deal in Bierens de Haan. Table 4.1 Factors that influence effectiveness of collaboration Factors Indicators (qualitative) Willingness and capability to cooperate - Interdependency between stakeholders - Gaps between experience, culture and knowledge should not be too wide - Stakeholders are committed (especially influential stakeholder) Towards a shared vision - Stakeholders are transparent clear about their goals and know the goals and preferences of the other stakeholders - Stakeholders are willing to search for a solution that will lead to mutual gains/aim for same solution - Vision is sharply defined and boundaries of the project are mutually set and clear Creating a collaborative atmosphere - Different stakeholder trust each other - Stakeholders communicate clear and open with each other - Team building activities are part of the process Collaboration management - Leader guides process and initiates interaction processes between actors - The role of each stakeholder is clear for the other stakeholders and the share of costs and benefits is well defined. - Continuity and learning is ensured by monitoring, reflection and evaluation 4.3 ANALYSIS: STRENGTH AND WEAKNESSES OF THE CONSORTIUM The factors discussed in the previous section are central for the analysis of the Green Deal Bierens de Haan. The input for the analysis is based on the interviews with the stakeholders that are member of the consortium of the Green Deal (Ymere, District Nieuw-West, Nuon, Liander, ASW and Waternet) supported by policy documents. The interviews are summarised in Appendix III. Willingness and ability to cooperate In this consortium, all conducted stakeholders are seemingly willing to cooperate. All of them indicate that they need each other (interdependent), either by sharing financial burdens, knowledge and material in order to achieve their objectives. There are indications that the gap between organisational processes, experiences and 22

24 knowledge is too wide. All of the actors state that at this point they are still learning about the internal processes and jargon of each stakeholder, and that this learning process delays the consortium to come to actions and decisions. Perhaps in time this will be solved, since ASW argued that sometimes different terms or principles are used, but later it turned out that the stakeholders actually mean the same thing. Here it is just a linguistic misunderstanding. Solving the gap between internal organisational processes requires more attention. A practical example: Liander pointed out that it needs at least 16 weeks preparation time between a go for installing technologies and actual installment, while Ymere expected that it can be done within two weeks. Most stakeholders (e.g. Liander and Waternet) argue that the collaboration is important for achieving sustainable renovation and believe that other stakeholders are committed as well. Despite the slow progress, the different stakeholders believe in the synergy this collaboration could result in, which indicates that stakeholders are committed. Nevertheless, for some actors the collaboration outcomes are more salient or urgent than for others. It also depends on the interest of each actor (e.g. Liander is strongly committed to saving energy, while this is less relevant for Waternet). What is important here, is that it has become apparent that the degree of influence indeed has an impact on the collaboration. All stakeholders point out that Ymere is an influential stakeholder, not only because it is the coordinator of the project, but also because the organisation is the only provider of houses. The corporation has therefore power to determine when and where actions take place. When Ymere does not move, no one else can. In the last years, there have been shifts in decisions by Ymere. For instance, there was little clarity about the areas of the pilot projects, which delays the project. Bierens de Haan is a pilot area at the moment, but was excluded at a certain moment in time, and now back in being a pilot location. Determining a second pilot location is going slow, since a location which has been chosen, is cancelled lately. This means that the consortium has to start again with choosing a location and making a plan for that location, and thus a delay in the project. The stakeholders do not doubt the commitment of Ymere, but argue that regularly shifts in their positions and decisions, inhibit the process. An explanation of these shifts is given by Liander: the stakeholders involved in the consortium are persons who represent a whole organisation. That person might be committed, but this does not necessarily account for the whole organisation. Furthermore, as Liander claimed (based on the experiences within other consortium's) when more than one corporation would be involved the process of decision-making regarding the appointment of locations would not be determined by one actor. In practice, this has led to more effective decision-making and implementation. Table 4.2 Key aspects of analysis Willingness and ability to collaborate Stakeholders have different complementary resources, are therefore independent: they think collaboration is important and are willing to collaborate. Differences in organizational processes, jargon and culture create sometimes misunderstanding. Ymere is most influential stakeholder. Shift in decisions by Ymere slow down the collaboration process. 23

25 Towards a shared visions In the project, Liander, Nuon, District and ASW seem very clear in their preferences and goals within the project (this is also confirmed by other stakeholders). However, according to some stakeholders, Ymere is not always clear about its own preferences and goals within the project. According to ASW and Liander this is not due to a lack of will (i.e. commitment, as mentioned previously), but they think that Ymere is internally struggling with what goals it wants to achieve. Furthermore, ASW, Nuon and Liander are explicitly curious about the goals of Waternet in this consortium. For them it is not clear what Waternet exactly wants within the consortium Waternet also acknowledges that it is still searching for its position within the consortium. They are currently developing its goals of what it wants to achieve. In November Waternet is expected to be able to be more clear about its goals. Part of this problem can be explained by the fact that Waternet stepped later into the consortium. There are also some problems with conflicting interests. A lot of different organisations are cooperating with different stakes in the project. So is Nuon supplier of city heating and does not want too much insulation in the houses, because the demand for city heating wil go downon the other hand is insulation of houses one of the goals of Liander and Ymere. Therefore it is important to take about the fidderent stakes and align them. The formal vision of the Green Deal is to retrofit houses more energy efficient in a fast and collaborative way (Ymere et al., 2011). When the renovating activities performed by the different actors are more aligned, it is expected that overall costs are lower, and also the nuisance for the inhabitants is lower (Ibid.). All actors signed to work for increasing the energy efficiency of existing houses in Nieuw-West. In practice, the shared vision is still not strongly integrated in the project. Partly this is due to the lack of transparency of individual goals of Waternet and Ymere. But, as Nuon states, since the start of the project, there have been added more and more actors. This requires the consortium to continuously adapt, and inhibits the achievement of a shared vision. Visionary decisions on which measures to take are still under development (it is too soon). Yet, on another level there seems to be a shared vision: all stakeholders envision to learn from this collaboration process for future projects. In the end, there is a need for sustainable renovation for all houses in the Netherlands (mentioned by Liander; AgentschapNL, 2012). Table 4.3 Key aspects of analysis Towards a shared vision Liander, Nuon, District and ASW are clear in their goals. Ymere is less transparent on its goals. Waternet is still developing their visions and goals. The formal vision/goal is retrofitting houses more energy efficient in quick and collaborative way, with low nuisance for residents. This vision is not put in practice yet. The current mutual vision or goals is mainly to learn from this collaboration for this and future projects on sustainable renovation. Creating a collaborative atmosphere In general, there is trust between different stakeholders in the consortium. There is believe that the collaboration can lead to an innovative project; a lot of stakeholders are enthusiastic about the collaboration. However, some actors point out that the regular shifts in decision, ambiguities or absence of clear goals tests 24

26 the trust in the collaboration. At some point results should appear, otherwise trust may decrease over time. As Nuon mentioned, it is still a bit too much talking, and not so much action. In line with this, ASW developed it own action plans in order to create more results. Whether this affects the trust relationships, is not assessed. Overall the communication between the stakeholders is open, although the communication between the representatives of organisations and the rest of the organisations can be improved. The members of the consortium are communicating open and transparently in general, although there is some uncertainty about the stakes and location of the pilot projects. We did not ask explicitly about the content and frequency of the team building activities, but at least one activity has been organised. The members of the consortium went to Frankfurt (16 and 17 October) to see projects in Germany. During this excursion, there was time for formal and informal contacts and interactions. So there are some attempts to positively influence the situation. And most stakeholder still have faith in the consortium, although the problems it has at present. Table 4.4 Key aspects of analysis Creating a collaborative atmosphere In general there is trust between stakeholders, but shifts in decisions and ambiguities test this trust. The slow process leads to the appearance of individual actions. The communication seems open. Stakeholders within consortium are however limited by organization they represent. Mutual activities that enable team-building are taken place Collaboration management In the consortium, ten different stakeholders are working together on sustainable renovation. Ymere is the coordinating stakeholder in the consortium and is responsible for the houses that need to be renovated. In practice, Ymere does not have a leading attitude at the moment (e.g. in changing the pilot locations). Therefore, the consortium is not making much progress; there is a clear end-goal, but the roadmap to that goal remains unclear (Nuon). Different stakeholders talked about a lack of clarity and transparency of Ymere and the influence this has on the collaboration (since Ymere is the most influential stakeholder). Liander stressed the fact that the management is not sharp at the moment and the organisation structure not clear. According to ASW, a better organisational structure, clear agreements and a definite division of roles are needed to improve the effectiveness of the consortium. The unclarity about the name of the consortium is an example about the weak organisational structure: the terminologies of Green Deal and Blok voor Blok are used interchangeably. A second element of collaboration management are the roles and responsibilities of the involved stakeholders. The core activities and role of each stakeholder is rather straightforward formulated in the project plan (Ymere et al., 2011). In the interviews the stakeholders confirm these activities, indicating that clarity on the roles is present in the consortium. For example, it is clear that Ymere is the coordinator. However, some confusion about the roles of the new stakeholder can be detected. They are also not included in the project plan. For example, the role of Waternet is for some stakeholders (Nuon, Liander, ASW) not clear yet. In the interview with Waternet it became clear that the organisation is likely to take a role as thinking partner and wants to be a promoter in the collaborative process regarding decision-making and implementation. 25

27 With reference to sharing of costs and benefits, the stakeholders are still searching for solutions. Within the consortium, stakeholders talk about sharing responsibilities (and costs), but organisational structures and traditional ways of working inhibit the opening up to search for new opportunities of sharing costs and benefits (De Bruine, personal correspondence, 2012). For instance, implementing water retention measures in the public area maybe beneficial to Waternet, while the District is paying for it. Questions about what is fair, and who pays what are key issues. Some stakeholders involved are not able or willing (the exact reason is outside the scope of this research) to directly invest in the project (Stadsdeel, ASW, Waternet). And new techniques give discussion on who has to pay for the construction and maintenance. It is difficult to change behaviours of big companies, which can limit the impact of new innovations. Nevertheless, stakeholders are open for finding new ways: the aim of the Green Deal is also to learn how to cooperate with the different parties involved. But the questions is to what extent this consortium can change traditional ways of working of the stakeholders involved. Although there is a willingness to cooperate, the consortium is not stable at the moment and is not leading to concrete results. Some plans are still under construction and pilot areas change often. Moreover, there is still discussion about the plan for Bierens de Haan. The last half year were mostly taken by talking about the consortium and what is needed to implement. Most stakeholders hope that some progress can be made soon. The consortium needs to organise the process well, so all the talking can lead to action. Various stakeholders have stressed the need to learn from this collaboration. Some stakeholders have taken their own initiatives to move forward, so is ASW working on a group on behavior and is making some progress in this group. Other stakeholders are worried about the relation between the relatively small pilot areas and the other houses Ymere will renovate in Amsterdam West and Nieuw-West; will this consortium really lead to a change in the way Ymere is renovating houses? In the project plan, a distinction is made between process and result monitoring and is the responsibility of the consortium (Ymere et al., 2011). However, the client, AgentschapNL, has appointed an independent evaluator to see what can be improved in the process. The preliminary results can be monitored after 31 December 2012, after the first year of the consortium (Ibid.). Table 4.5 Key aspects of analysis Collaboration management Strong leadership is not present yet: coordination of Ymere is not stable or transparent. A process leader is present. Core activities are well defined in plan, but it is yet difficult to step out of traditional roles. Stakeholders are searching for solutions to share costs and benefits. Process and result monitoring is planned. Focus on result is maybe too early. 26

28 4.4 CONCLUSION AND RECOMMENDATIONS The aim of this chapter is to give insight in the factors that influence the success of the collaboration process. Starting with the strengths, the different stakeholders working together is an opportunity to experiment and change the normal processes of renovating houses. The commitment of the stakeholders are factors in which the consortium is doing very well. Stakeholders claim they believe that the collaboration will be beneficial for all stakeholders. Some actors are willing to cooperate even longer then the set time limit (2015). Furthermore, the stakeholders feel that this collaboration is already valuable for learning, despite the actual outcome, because they think they will be working more in such a multi-actor arrangements in the future. Therefore the scalability of the learning is also important. Meetings and workshops are organized to foster learning. Also, there is no sign of real distrust. Despite the shifts of the decisions of Ymere testing this trust, the actors that are consulted show confidence in each other and in the possibilities of this collaboration. But, their patience might not be infinite. At the moment, the collaboration has not resulted in many concrete result. There multiple shifts in decisions, especially regarding the locations of which houses/area will be at the target of the project, is appointed as a major cause. The lack of progress in decision-making started individual actions of some actors: it is still a consortium of talking. This has led to individual actions: ASW took up its own action plan. Whether this beneficial for the collaboration cannot be assessed. However, the stakeholders are still getting to know each other processes. The terms and processes are not aligned, which creates misunderstanding and delaying the actual decision-making. Moreover, conflicting interests can arise by differences in stakes and processes. An example is that Nuon does not want too much energy reduction, because then the city heating is not enough used. Also, the organizations, such as Ymere, within the Green Deal are represented by single persons. Even when they are very willing to cooperate, it might be that they do not get permission from the organization they represent. Furthermore, the group of stakeholders is still exploring each others roles (and responsibilities). For Waternet, the major problem is the absence of a clear role in the consortium. The other members of the consortium have no idea what Waternet wants to do within the consortium. It is therefore important that Waternet thinks about their role and their goal of participating. What do they want to achieve? Which techniques do they want to test on small scale? And Waternet should communicate their vision and goal with the other stakeholders, so they can work together and move forward. Also Ymere is not always transparent about what it wants. Another point is that organizations within the Green Deal are represented by single persons, even when these persons are fully committed, it might be that they do not get permission from the organization they represent. An important but difficult issue is the distribution of costs and benefits in the project. A lot of parties involved in the consortium are not able or willing (the exact reason is outside the scope of this research) to directly invest in the project (Stadsdeel, ASW, Waternet). And new techniques give discussion on who has to pay for the construction and maintenance. It is difficult to change behaviors of big companies, which can limit the impact of new innovations. In general, the consortium needs to pay attention to the process in order to come to action. Ymere has difficulties leading the consortium and deciding where to start pilot projects while the other stakeholders are dependent on Ymere since they own all the houses. And the representatives of Ymere who are part of the consortium are again depending on the management of Ymere; they are also depending and now free to decide major things (such as a pilot location). The organizational structure is not clear yet. A good process is likely to lead to better decision-making and implementation. It can be concluded that the consortium is a good attempt to work together with different parties and change the way in which houses are being renovated. But the experiences of the consortium also show the difficulties of working with different parties. 27

29 5. SUSTAINABLE RENOVATION CRITERIA [THOMAS AND TIES] 5.1 INTRODUCTION Sustainability is a hot topic in the current society. Unfortunately, the word sustainability can be interpreted in many different ways. In the case of construction and renovation sustainability is often proclaimed, but it is not always clear to what extend sustainability is implemented. In order to define whether investments made in a construction or renovation project are sustainable, sustainability criteria will be presented in this paragraph. Those criteria will be used as guidance for assessing sustainable techniques. In this case the techniques are already specified for the Bierens de Haan renovation project, but the criteria can be used to assess techniques considered in other renovation projects as well. These criteria for sustainable renovation are based on: Planet, Profit and People (Elkington, 1994). In order to implement sustainable innovations in a renovation, different aspects of planet as well as people and profit should be considered. Economics is an important driver of the implementation of innovations. The cost of installing and maintaining a new technology should not pose a barrier to the stakeholders. Social acceptance of an innovation is of importance as well. If there is no acceptance by the residents, a technology will not be used. With the help of case and literature studies the stakeholder s acceptance must be researched. Furthermore, in the Bierens de Haan project no weight is given to the cultural-historical and architectural aspects of the site. 5.2 CRITERIA To determine whether certain techniques are feasible to implement in a renovation project and in order to compare the technologies, a set of ten criteria is presented. The basis for these criteria can be found in sustainability criteria presented by Boer and Willems (2010) and Leeuwen et al. (2011). From these frameworks a selection is made based on the applicability in a renovation project. Scoring of the criteria for each technique is done using corresponding literature and/or interviews with stakeholders. Furthermore, the importance of different criteria differs from client to client, and the choice of the most important criteria is thus dependent on the reader s interests. Therefore the choice is made to weight each criteria in the same way, the reader can choose to focus on the most important indicators for their specific case. To give a clear overview on a techniques performance some criteria is scaled with a + for a positive effect, a - for no effect or a negative effect. For the criteria of which the exact numbers are known, the values are presented. The results per technique will be shown in a summarizing table at the end of chapter 6. Below the criteria will be explained in table

30 Table 5.1 Sustainable renovation criteria Criteria Cost of retention capacity Percentage of a 18 mm h -1 rain event retained Lifetime Water use reduction Energy savings Increase in green area Connection between residents and water Social acceptance Responsible for the implementation Benefits stakeholders Description The economic efficiency of a technique to store one cubic meter of rainwater. To determine the cost, the installation costs are used. Those costs are divided by the amount of cubic meters the technique can retain; this gives the cost per m3. An important measure is a techniques capability to reduce peak flow during intense rainfall events (18 mm/h). According to Buishand and Wijngaard (2007), such events occur every 2 years. This criteria is a measure for the total capacity to reduce water discharge during intense rainfall events. The result is retained water as a percentage of the total rainwater amount that falls on the whole Bierens de Haan district. Amount of years a technique can be in use. Is there a water use reduction due to the implementation of the technique +, if not, -. Is there an energy or gas use reduction due to the implementation of the technique +, if not, -. Is there an increases in green surface area due to the implementation of the technique +, if not, -. Does the technique tribute to more awareness on water. + if yes, a - if not. Are the residents willing to implement and use the technology, if yes +, if not -. This information is gathered not only from literature, but also from neighbourhood interviews. Which stakeholder can be held responsible for implementing and maintaining the technique. Which stakeholder benefits from the implementation of the technique. 29

31 6 ASSESSMENT OF TECHNOLOGIES [TIES, NIEK, LISANNE AND PAULIEN] 6.1 INTRODUCTION Nowadays, the urban water cycle focuses on a fast drain of rainwater and domestic wastewater to the sewage treatment facility or surface water through a separate sewage system in the neighbourhood (Pötz and Bleuzé, 2011). A separate sewage system makes use of two pipelines; one for the wastewater discharge and one for rainwater discharge. A centralised water system for sewage and rainwater leads to large amounts of both waste and drinking water transport. By retaining water in the neighbourhood, a decentralised water cycle can be implemented, which focuses on retaining and using the water already present in the neighbourhood. As chapter 3 shows, there is a low risk of drought and flooding in the Bierens de Haan neighbourhood. A selection of different technologies which can counteract those rainfall issues - and make the neighbourhood become part of a decentralised water cycle - has been made. In this chapter an answer to Which techniques are economically, technically and politically feasible in and around the existing houses to retain and/or reuse rainwater? will be given by introducing options that can play an important role within our project case in Amsterdam Nieuw-West. There is a large range of technologies that can be implemented to reduce the amount of rainwater entering the city's water system and causing problems during peak rainfall events or improving provision of water during periods of draught. The goal set by Waternet is to look at decentralised options. Therefore, options for in house rainwater retention are suggested by looking at green roofs and water storage options. The rainwater retention in public areas have options such as implementing public green spaces and several infiltration technologies. Feasibility of the different implementation options will be tested on technological base, financial analysis, policy and the sustainability criteria mentioned in chapter 5. The social acceptance of the residents for the different technologies is tested through interviews. These interviews can be found in Appendix IV. The general tendency is that due to the high age of the residents there is little interest in rainwater retention measures. Moreover, because they do not experience water nuisance they feel no direct need for these measures. Further obstacles they mention to implement water retention technologies are possible increased rent and extra proceedings causing a longer delay of the renovation. On the other hand, most residents are willing to support technologies if there are potential savings due to lowering of the energy and water bill, even if the rent is raised. Furthermore, the fact that most residents find that climate change and the environment are serious topics offers opportunities. From the interviews with the stakeholders in the Green Deal, it showed that not all participants think that it will be feasible to implement rainwater retention measures in the project of Bierens de Haan. The renovation already started and the project is now focused on energy. For all technologies, comparable data is needed to check how they score on the criteria, like the amount of peak rainfall, surface of the neighbourhood, roof surface, price of drinking water, these can be found in table

32 Table 6.1. Characteristics of the neighbourhood, amount of heavy rain per area and prices that are needed as input for the discussion of the technologies. Characteristics Surface [GIS] 6 - Total area - Paved roads - Paved pathways - Sloped rooftops - Flat rooftops - Approximate covered surface m m m m m m 2 Number of houses 177 Horizontal projected surface of 1 sloped rooftop 40.7 m 2 Surface of 1 sloped rooftop 50 m 2 Heavy rain [Buishand and Wijngaard, 2007] 18 mm/hour Rainfall on surface - Total surface area - Paved roads - Paved pathways - Sloped rooftops - Flat rooftops - Approximate covered surface 630 m m 3 72 m m 3 9 m m 3 Price drinking water [Waternet, 2012] 1.26 /m 3 Price electricity [Eneco, 2012] /kwh Price natural gas [Eneco, 2012] /m 3 The financial feasibility of the technologies is based on the upfront investment costs. Since Waternet does not make use of discounting their investments, all investments are depreciated immediately after the investment has been done (Interview with De Bruijne, 2012; Appendix III). A small analysis of the technologies is done with the sustainability criteria mentioned in chapter 5. This data will result in a list of feasible technologies and their respective effects. This can later be incorporated in a tailored advice of what scenario to follow for reducing the peak water discharge of the Bierens de Haan neighbourhood within the Nieuw-West district of Amsterdam. 6 Note that uncovered surface includes residents owned gardens, which are sometimes paved. Due to the small surface area of each garden, and the differences in pavement per site, it was impossible to properly measure using GIS data. 31

33 6.2 GREEN ROOFS Theory Green roofs are roofs that are covered with vegetation (see figure 6.1). In the case of Bierens de Haan the focus is on extensive green roofs, these are roofs covered with moss and sedum plants. The reason for this is that in most cases, roof construction enforcement is not required. The thickness is between 2 to 10 cm and the weight 20 to 200 kg/m 2, depending on the wetness (Gemeente Amsterdam stadsdeel Nieuw-West, 2012). Extensive green roofs are the most common type of green roof since they require little maintenance and are less costly. Theoretical benefits of green roofs are water retention, improved thermal and sound insulation, capture of fine particles, a decreased urban heat island effect and increased biodiversity. Reasons for implementing are aesthetics and care for the environment while barriers are mainly costs and effort. (Livingroofs, 2012). Figure 6.1, green roof. (Dakdokters, 2012) Application The investment costs of an extensive roof range from 25 to 100 per m 2 depending on the slope of the roof; the steeper the roof, the higher the costs. Maintenance costs range from 1.50 to 4.00 per square meter per year (Bourdrez, 2012). With a total roof cover of 50 m 2 the total cost per household would be 625 to 2500 (including subsidies). If the initial investment is financed over a period of ten years, the cost per household per month for the installation and maintenance would range between and On an individual basis there is no profit to be achieved. The reduction in heat loss varies between 10% and 30% during wintertime. So in the three months of winter with an energy bill estimate at 100 euros per month, 30 to 90 can be saved, which could be 2.50 to 7.50 per month spread out over a year. Unfortunately, in the future, all houses in the neighbourhood might be connected to district heating 7, their energy bill will become 7 Depending on which stakeholder you ask whether district heating will be implemented, different answers come up (interviews, ASW, Liander, district Nieuw-West) 32

34 lower. Therefore, the returns of the investment in the green roof will be lower. Energy savings would not compensate the investment. The cost of retention of one cubic meter in an intense rainfall event (18 mm h -1 ) is calculated by dividing the implementation costs per household ( 625 to 2500) by the retention capacity per household. In case of an intense rainfall event an average of 65% (Metselaar, 2012) of the rain that falls on the sloped roof is retained (0.48 m3). The costs per cubic meter rainfall retention are then estimated between 1313 and The total capacity of green roofs to retain the water that falls on the whole neighbourhood is limited to 65 percent of the rain that actually falls on the sloped roofs on which the green roofs will be installed. 65 Percent of the total rain that falls on sloped roofs in the neighbourhood is 84 m 3. This means that 22 percent of the total amount of rain in the neighbourhood can be retained by green roofs. Implementing a green roof could be hard, because there is no major benefit for an individual household. Only when there is a collective initiative to construct green roofs in a neighbourhood, the previously stated advantages become clear. On the individual scale green roofs are beneficial for an increase in heat and sound insulation. However, these individual advantages do not cover the costs of installing a green roof. Other stakeholders that could benefit from green roofs are, Waternet, Ymere and district Nieuw-West. For Waternet the benefits are rainwater retaining between 55% and 75% (Metselaar, 2012), which causes a delay in the peak-runoff during extreme rainfall events (Berndtsson, 2010). The role of Waternet in implementing green roofs should be mobilizing Ymere and the district Nieuw-West. For Ymere a green roof protects the original roofing structure of a building and results in the extension of its lifetime (Castleton et al., 2010). Certain studies show almost a doubling of the roof lifetime to years (Bianchini and Hewage, 2011). Ymere could be held responsible for half of the initial investment and the maintenance. These investments can indirectly be funded by an increase in rent of the residents. Ymere should contact an installer (i.e. Dakdocters or Livingroofs) for the installation and maintenance of the green roofs. The other half of the initial investment can be done by district Nieuw-West. The district Nieuw-West in Amsterdam (2012) offers a subsidy for green roofs. Up to 50 percent of the tot construction cost can be compensated to a maximum of 50 per square meter. Additionally there is funding for structural calculations ( 500) and for environmental permits ( 200). There are several advantages for the residents; reduction in heat loss during winter, cooling in summer, and sound insulation (van Renterghem and Botteldooren, 2011). If implemented on a larger scale the effect of removed small particle pollutants through absorption and interception may become clear (Livingroofs, 2012). However there is no real connection between the residents and water. Green roofs do not create a larger awareness under the residents. On average there is a social acceptance for green roofs. During the interviews in the neighbourhood obstacles were extra proceedings that might possibly cause an even longer delay of the renovation and also the idea that green roofs need a lot of maintenance (General outcome inhabitants interview, 2012; Appendix IV). Opportunities can be found in the extra advantages green roof provide, mainly insulation, and in the fact that it gives the neighbourhood a greener appearance. The residents are divided on if are green roof attractive to look at or not. An advantage for no specific stakeholder in particular is that green roofs can provide food, shelter and in general living space for mainly birds and invertebrates. In contrast to city landscapes that are not animal friendly, green roofs can provide habitats in areas lacking green areas. They can also function as a link between several habitats or provide additional habitats for rare, protected or otherwise important species (English Nature, 2003). The ability of green roofs to harbour rare plants is strongly limited because of the harsh conditions found on green roofs. The rather thin substrate layer only allows drought-tolerant plants. Overall green roofs can be described as a similar habitat to rock barren ecosystems like cliffs (Lundholm, 2006). 33

35 6.3 STORAGE AND REUSE OF PRECIPITATION IN HOUSE Theory In order to lift pressure from the sewage system, households can choose to implement rainwater storage units to harvest rainwater. The main motivations for dwellers to acquire a rainwater harvest system are environmental conservation, subsidies and becoming self-sufficient in terms of water supply (Domènech and Sauri, 2011). On a small scale the easiest way to harvest the rainwater is through implementing a rainwater barrel in the yard (Guo and Baetz, 2007). Also a more advanced water tank or water bag can be implemented (GEP, 2012). The most successful uses of rainwater in a house do not require extra effort from the residents. This was however, one of the concerns of the residents that came up during the interviews conducted in the Bierens de Haan neighbourhood (General outcome inhabitants interview, 2012; Appendix IV). The harvested rainwater can be stored in or around a house in order to use it for domestic purposes, such as watering gardens, toilet flushing, the washing machine, and cleaning in and outdoors (Gardiner, 2010). This will save high quality drinking water, which would otherwise be used for these purposes. In some countries or areas, new build houses are obliged to equip the house with a precipitation harvesting system, for instance in Belgium it is obliged to for houses with a roof area of 100 m 2 or more (Vlaams Ministerie Ruimtelijke Ordening, 2004). Even though rainwater can be used for several purposes, according to research households with a rainwater harvest system use it mostly for irrigation purposes (Gardiner, 2010; Domènech and Sauri, 2011). If the precipitation is also used for other purposes, the advantage of the system will increase. A survey conducted by Vewin (2011) states that the average daily water use of a Dutch citizen is L (table 6.2). The survey does not include the outside water tap, therefore not all water use in the garden is included, and possible neither car washing. The expected average outside water use is 3.8 L per person per day (Vewin, 2011). Therefore, the amount of drinking water that can be replaced by rainwater is 52.9 L per person per day. Table 6.2. Water use by a Dutch resident per day in L (Vewin, 2011) Water demand Amount of water [L] Percentage [%] Shower Sink Toilet Laundry Dishwashing Drinking and cooking Others kitchen Total The roof of a house in the Bierens de Haan neighbourhood has a surface of approximately 40.7 m 2 and an average precipitation as shown in table 6.3. The average amount of rain that reaches the rooftops can be calculated by multiplying the amount of precipitation by the horizontal area of the roof. The potential of captured water on the roof and the rainwater used by a two person household is shown in table 6.3. In total, 34

36 an annual reduction of 33.1 m 3 drinking water per household can be reached. As depicted in table 2, only two of the twelve months have more net rainfall than is used by a household. It is therefore not possible to be selfsufficient in water supply for named applications with the water use of an average Dutch citizen with this roof area. Taking the expected outside water supply in mind, the water barrel can save up to 1.4 m 3 drinking water per person per year. Table 6.3. Storage capacity and possible use of rainwater in a two person household in Amsterdam Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Average railfall [mm] Storage capacity [m 3 ] Average use [m 3 ] Nett [m 3 ] For harvesting the rainwater, two different technologies are analyzed. First the rainwater barrel is researched in order to gain knowledge about a technology that is spread in the Netherlands. Secondly, the water tank and water bag are investigated as a means of water storage and reuse. A rainwater barrel is installed outside and is attached to the rain pipe (Karwei, 2012). Private rainwater barrels allow households to use the collected water for domestic purposes such as landscaping, hardscape cleaning and maintenance purposes according to Guo and Beatz (2007). However, the retention possibilities are limited because the amount of water used by inhabitants for domestic purposes limits the amount that can additionally be stored during periods of heavy rainfall (Xanthoulis, 2010). On average, a rainwater barrel costs 40 euros and stores approximately 100 liters of water (Thuistuinieren, 2012; Kunstof Regenton, 2012). Research by Seo et al. (2011) shows that connecting multiple rainwater barrels in a neighbourhood is also an effective measure. This research shows that it is only dependent on the water use by the households; if there is homogeneous use of water, everyone uses as much as they would if they had their own water barrel, there is no use to connect the rainwater barrels. It might be useful, however, when the use is heterogeneously spread and some inhabitants are not inclined to use the water caught in the neighbourhood. There are different kinds of tanks that can be used for water storage: a concrete rainwater well, a plastic or concrete water tank to be dug into the garden, a water bag in the crawlspace and a tank for inside the house (GEP, 2012). A tank can be made at any desired size and have a lifetime of 25 years. Most of the tanks for underground can carry the weight of a passenger car, except small concrete tanks (smaller than 5,000 L), and need excavation work for a minimal depth of 1.25 m in order to fit in. In case of a renovation a water bag (see figure 6.2) in the crawling space is a good alternative. This way, no excavation work is needed, which saves work and money. The size of the storage facility will depend on the number of inhabitants in a house and the projection of the roof area in the horizontal plane. 35

37 Figure 6.2. Water retention bag in a house (EFrarain, 2012) The water bag can either be installed with or without a heat pump. The heat pump withdraws heat or cold from the rain, and can be used from 3.5 C on (Klimarain, 2010). Benefits regarding lower fossil fuel use for heating depends on the initial condition of the house, status of insulation, surface area, desired living temperature, and number and size of radiators. When all these factors are taken into account, it is possible to reach a 25 to 30 percent energy use reduction by using a energy efficient heat pump with respect to a conventional natural gas boiler (Klimarain, 2010). By using retained precipitation for flushing the toilet and laundry washing water demand, the water will be wastewater afterwards. This will be disposed in the sewage system. In the end, Waternet has a lower input of rainwater, however the amount of water that needs to be dealt with at the wastewater treatment site stays the same. Nevertheless, according to Domènech and Sauri (2011) the user of a rainwater harvesting system is more connected to the water cycle, and therefore more aware of their water use, which can have an influence on their water use habits and awareness of water scarcity problems, now or in the future. It is important to notice that before precipitation can be used for application in houses, attention must be paid to the water quality (VIBE and Dialoog, 2008). The materials used for the roofs, gutters and rainwater pipes need to have a low pollution potential. If it is made of zinc, lead, asbestos, PVC, etc., the rainwater is contaminated and not safe for usage (VIBE and Dialoog, 2008). Application Water barrel Using the water barrel in the Bierens the Haan neighbourhood is an option. The investment costs are low, 40 per household, and the maintenance costs are almost non-existent. Next to that, by saving maximal 1.4 m 3 drinking water per person per year, the water savings could rise up to 1.76 per person per year, but the small size of the gardens must be taken into account, so maybe not all water is saved. The only trouble with installing these rainwater barrels is that the amount of retention capacity is limited by the usage of the inhabitants. 36

38 Therefore, we used the interviews conducted with the inhabitants to see whether they are willing to use the water from the barrel. And the general opinion was that half of the questioned inhabitants would, but the other half wouldn t use it. If they wouldn t want to use it, this was mainly due to a lack of plants in the garden. Since the inhabitants need to use the water in order to reduce peak flow pressure on the sewage system since the barrel is full and all rainwater will be transported into the sewage system immediately. Apart from the willingness it s important to notice that the technology is easy to implement and doesn t change the appearance of the neighbourhood. The only problem that needs addressing is the smell of the barrel and the appearance of mosquitoes when it s a warm summer. By installing the water barrel in the front- and backyard, this implementation is most beneficial for the inhabitants. Also, it could be an extra advantage for Ymere, since it improves the appearance of the neighbourhood. Waternet is not really benefiting from this implementation, but it increases water use awareness. Water tank or water bag Since the houses and gardens in the Bierens de Haan neighbourhood are rather small, the options for a water well in the garden and an inside water tank are not preferable. The houses were built in the 50s without a crawling space. However, due to lowering of the groundwater table, the soil beneath the houses has subsidised, leaving a space exposed below the houses (Personal communication with Marc van Arem, 2012; General outcome inhabitants interview, 2012; Appendix IV). There is a gap in the foundation of these houses, and together with this newly developed space, the insulation of the bottom of the house is decreased. In case the bag is placed before this ventilation strip energy will be saved and the living comfort will increase. However, the bag is usually placed with some space left at the top. Therefore, this option needs more investigation, since it is not a standard situation. During the renovation a gap will be made in the foundation for the new piping and electricity cables, which creates the opportunity for installing a water bag under the house. Positive side effect of using rainwater for laundry washing is that less detergent is needed and there is no need for fabric softener at all, because rainwater is softer containing less lime than drinking water (Milieu Centraal, 2012). This leads to fewer detergents in the environment. Since the amount of rainwater use is similar to the captured amount, see table 2, the water bag or tank can not be used for extra storage. The capacity of the water tank should be large enough to fulfill the water requirements in case there is a drought of 21 days (Kingspan, 2009). This taken into account, the required capacity is 2,100 L, and therefore the optimal capacity is 2,500 L. When a water bag or tank of 2500 L is installed at a house which has a flat roof surface of 40.7 m 2, the maximum amount of rain it can cope with is 610 mm. In case of the heavy rainfall of 18 mm per hour, 0.73 m 3 rain will fall on 1 roof per hour, a tank of 2500 L is capable of storing this amount, even when it is half full. Therefore, 33% of the peak flow, 130 m 3, in the covered area of Bierens de Haan can be retained by water tanks installed in houses. However, the water storage device should have room left at the time this precipitation is falling. A water storage facility up to 3,000 L, including pump, filter and installation, costs between 2,000 and 4,000 euro (Waterco, 2012). Therefore, the cost for a retention capacity of 1 m 3 is 2,730 to 5,480 euro. In total, by making use of the watertank, 33.1 m 3 drinkwater can be saved per household can be reached. This results in a cost saving of 42 per year. Therefore, the water tank will not be cost effective if it only saves drinking water. In case a water bag in combination with a heat pump is installed, heat recovery will decrease the natural gas bill with 25-30% (Klimarain, 2010). On average 1,500 m 3 natural gas is used per year in a terraced house in district Nieuw-West (former name Stadsdeel Geuzenveld en Slotermeer) (CBS, 2012). This means that 375 m 3 natural gas per year could be saved, with a cost of 267. In total, water and natural gas 37

39 savings per year can rise up to 309 per year per household. In case the neighbourhood is going to be attached to district heating, the benefits of the water bag in combination with the heat pump will reduce. Further benefits for a household are the enhanced life time of machines, due to no calcification in the washing machine and toilet. Locating a water tank below the level of use requires energy use for pumping the water to toilet, washing machine or outside tap. The energy use that is needed for pumping the water around is in cost negligible in comparison to the water savings (Klimarain, 2012). In case a household is equipped with a water tank, it will require direct engagement with the technology, and therefore there should theoretically be more awareness of the quality and volume of water being used (Gardiner, 2010). As a result, the overall water consumption can reduce after installation of a rainwater harvesting system. To use the water bag for the retention of rainwater in the most efficient way, it is wise to think about adapting washing plans to the weather forecast. This will increase the captured amount of rainfall and increases the storage capacity of the water bag. For installing the water bag, the following stakeholders are involved: inhabitants, Ymere, ASW and Waternet. Ymere is the most logical investor as the houses are rental houses. They will increase the monthly costs for the renters, since these will have lower fixed costs, which could be as much as 25 euro per month. Next to this, Waternet also benefits from the water storage, since they need less peak flow measures to adapt to the future. Also, the demand for drinking water will be decreased. They, however, do not have to invest in this technology, since the benefits for the residents are high enough. ASW can help to introduce the technology to citizens and notice the problems that occur in during use. 6.4 A LOW LYING PUBLIC GREEN SPACE THAT DOUBLES AS A STORAGE POND Theory Another way of dealing with excessive rainfall is incorporating the water in playgrounds for children or public spaces. In the Nieuw-West district, there already are some initiatives by inhabitants to create playgrounds in which all the seasons are represented (GraBS, 2011). In Rotterdam, this process was already started in 2007, where a schoolyard is transformed, so that in the event of heavy rainfall, small islands appear. This is done to create a playful atmosphere and to deal with all the water in the build environment (AD, 2007). Rotterdam also has another scoop by being the first municipality in the Netherlands with a watersquare (Volkskrant, 2012). This square is especially designed to form pools at three different levels during heavy rainfall events. The water will be led through the streets into the pentagon shaped square where it will be retained in basins. The basin ground consists of a special brick that infiltrates the water into the ground. The implementation of this park was very capital intensive; more than 2 million euros were spend to construct the park and adapt the streets. Another option that might also be considered are sports fields, but most sports fields are not capable to hold a lot of water. Most of the time, sports clubs have trouble keeping the water balance on their sport fields in the right conditions, but could be altered with a different drainage system (Regenwater, 2012). Another option for catching rainwater and keeping it from entering the sewage system is by implementing small public green spaces. These public green spaces can be used for several purposes, for instance relaxation and the general appearance of the neighbourhood. Research shows that green areas improve the livability of a neighbourhood (Shashua-Bar and Hoffman, 1999). 38

40 Application Before some of these options can be implemented in the Bierens de Haan neighbourhood, the general demographic situation must be taken into account. The average age in this neighbourhood is 62 year, so there is no specific need for a children s playground. Next to this, a sandpit is located in the center of the neighbourhood, but no one makes use of it (General outcome inhabitant interview, 2012; Appendix IV). This narrows down the scope towards the public green spaces, since there are few children in the neighbourhood making use of playing fields. In order to collect the required amount of peak rainfall, three different branches of public green space are going to be placed in the neighbourhood. These three branches will all be approximately 100 m2 and will be half a meter lower than the normal surface. This is due to the extra storage capacity that will be generated for the increased rainfall. The public green spaces can be used in dry periods for relaxation, with benches and small stairs that will make the public green space available for the inhabitants. The costs of creating these public green spaces are determined by calculating the costs of removing the existing tiles in the communal areas and the placing of the greenery. Also, some maintenance costs must be taken into account. Therefore, it is difficult to give the cost for a public green space. With information form other projects (Pötz and Bleuzé, 2011), it is estimated that the costs for a green space will be approximately 172,000. After the rainfall, the water will slowly infiltrate in the ground, so there are no costs necessary for removing the water. It will take approximately 10 hours to infiltrate after an excessive rainfall event. The water will not be reused for other purposes, so there are no extra costs required for that (Pötz and Beulzé, 2011). The implementation of the public green area has the most benefits for the general appearance of the neighbourhood. It adds green to the neighbourhood, it retains rainwater in an effective way and the public green space can be used for at least 20 years. This is most important to the Stadsdeel Nieuw-West and, but less important, for Ymere. For the inhabitants it adds a certain value, but not all inhabitants share the same view on the green appearance of the neighbourhood (General outcome inhabitant interview, 2012; Appendix IV). Eventually, stadsdeel Nieuw-West will be responsible for the initial investment and the maintenance work. 6.5 INFILTRATION SYSTEMS Theory Unlike many solutions that are placed above ground, water can also be stored in aquifers beneath the ground. The advantage of infiltrating rainwater in the catchment area is that it brings the system closer to its natural situation. The infiltrated water replenishes the natural aquifers and because most of the system is underground it causes minimal disturbance to existing infrastructure. There are, however, certain risks involved. The pollution level of the infiltrated water needs to be low in order to prevent groundwater pollution and also the infiltration systems need to be maintained in order to prevent clogging (Alfakih, 1999). Depending on the onsite characteristics (Predicted run-off, available space, soil characteristics etc.) different possibilities exist to infiltrate rainwater. Firstly the different types of infiltration systems will have to be analysed in order to assess which are possible in the Bierens de Haan neighbourhood. From literature the following systems of infiltration were found (Beeldens, 2008, Houwing, 2005) 39

41 Diffuse infiltration systems Centralised peak infiltration Centralised peak infiltration and reuse Centralised seasonal storage In the sections below these different systems will be analysed for the purpose of rainwater storage in the Bierens de Haan neighbourhood. Firstly a general description is given for each system and afterwards the application in the Bierens de Haan neighbourhood is assessed. Application An important factor in the application of infiltration systems is the type of soil present at the location where the water will be infiltrated. The main question is whether or not it is enough permeable to allow the rainwater infiltration. Research by de Gans (2011) shows the entire Amsterdam area is built on a layer of peat and clay of at least 5 meters (see figure 6.3 below). In order to improve the stability of the soil, layers of sand have been added in certain areas. This layer is thickest under the city center and the Tuinsteden built in the 50 s and 60 s (de Gans, 2011). Since the peat and clay soils have a very low permeability it seems logical to assume that infiltration is only possible in those areas with added sand. Although this might be true for the Diffuse infiltration systems it is not necessarily true for a Central infiltration system. According to research by Houwing (2005) a deeper aquifer can be used just as well for water storage. At a depth of around meters the first layer of Pleistocene sands capable of significant storage is found (de Gans, 2011). At this depth the investment costs will be higher, due to deeper wells. As a result the capacity will be higher than shallow infiltration. How these systems work and compare is elaborated in the the following two paragraphs. Figure 6.3, Example of a crossection of the soil in the Amsterdam area. (De Gans, 2011) Diffuse infiltration systems Diffuse infiltration means infiltrating the rainwater exactly where it falls. This can be done by creating more green areas or the installation of porous roads and pavements (Booth et al, 1999) Green areas in the city have many additional benefits next to rainwater infiltration but obviously require space and therefore are expensive to create within the city. Porous roads and pavements allow rainwater to infiltrate through pores in or between stones into the sediment. Research from Booth et al. (1999) showed that there are different types of diffuse 40