A comparative scenario analysis of WSUD measures for stormwater management in Amman, Jordan

A comparative scenario analysis of WSUD measures for stormwater management in Amman, Jordan Tarini Sharma REAP Master Thesis A comparative scenario analysis of WSUD measures for stormwater management in Amman, Jordan Submitted in fulfillment of the requirements for the degree: Master of Science Resource Efficiency in Architecture and Planning HafenCity University Hamburg Author: Tarini Sharma (6078153) Supervisors: Professor Wolfgang Dickhaut (HafenCity University) Daniel Schumann-Hindenberg (Hamburg Wasser) Date of submission: 26.06.2024 4 Acknowledgments I want to take this opportunity to thank Prof Wolfgang Dickhaut for his expert guidance and feedback during this project. Also my deepest gratitude to Daniel Schumann Hindenberg for his constant support, insights and feedback throughout the various stages of my thesis. I would also like to thank the entire E1 team from Hamburg Wasser for the opportunity to work with them and learn so much, even beyond the scope of my project. I also would like to acknowledge the support extended by Mahmoud Moursy who greatly helped me choose the right methods and approaches to begin my analysis and for providing some key resources. Furthermore, I would like to thank everyone who has accompanied me on this journey - my fellow REAP classmates - Kiana Sasani, Dounia Chlyeh, and Aaron Wieland for listening to my endless doubts and complaints and providing expert counsel. A special shout out to Gabriela Lugones Guzman for being my study partner and constant cheerleader, and to Norbert Brinz for his acute observations and technical expertise. I am also deeply grateful to Malte Graefe for seeing me through this journey and supporting me through his wise counsel and kind deeds. Last but not the least, I wish to express my gratitude to my loving parents and sister Charu for their constant support without which I could not be the person I am today. 5 Abstract Jordan is one of the most water-scarce countries in the world. At the same time, it has faced many flash floods due to the topography and rainfall patterns in the region. However, Jordan’s vulnerabilities to these water shocks have been exacerbated due to factors like climate change, rapid urbanization, a huge influx of refugees and the lack of proper management to keep up with these changes. With increased international cooperation, Jordan has committed to achieving various climate goals, however, the implementation of these policies into practice has been a challenge. This Master’s thesis aims to analyse the effects of integrating water-sensitive urban design measures into urban areas in arid and semi-arid climates. This is done by conducting an urban analysis of a catchment in Amman, a developing area called Marj Al Hammam. In this catchment, certain hotspots are identified that are at high risk of flooding, and at the same time present a potential to implement WSUD strategies. Further, three scenarios are envisioned - business as usual, interventions in public spaces and the inclusion of private spaces for stormwater management. While these hotspots vary greatly in their typologies, a common inference was that in the current state, maximum damage would incur due to stormwater runoff. The lack of open public space available according to the current land use plan poses a challenge to integrate WSUD, however, even in the minimal spaces available, its impact is quite apparent in terms of reducing and attenuating stormwater runoff volumes and runoff velocities. Further integrating these measures into private areas, especially rainwater harvesting has a huge impact on the overall system hydrology. Moreover, with strategic storage and treatment, stormwater runoff can be a good source of water supply during the dry periods in Amman. Additionally, these measures come with many ecological and social benefits - improving the microclimate, promoting biodiversity by bringing nature into the city and providing dynamic spaces in the city for people to come together, hence improving the overall quality of stay. The planning and implementation of these measures, however, should be done with stakeholder workshops and public participatory programs. Thus this analysis concludes with recommendations for the further development of the catchment and directs the path to further research on the detailed design of measures, to make Amman a resilient, green, just and inclusive city. Keywords: water sensitive urban design, resilient city, flash floods, stormwater management, rainwater harvesting, reduction of runoff volumes and discharge rates Table of Contents Acknowledgments ................................................................................................................................ 6 Abstract .............................................................................................................................................. 7 List of Tables ....................................................................................................................................... 12 Abbreviations ...................................................................................................................................... 12 Glossary ............................................................................................................................................ 13 Chapter 1: Amman’s Urban waters: Issues and Opportunities .......................15 1.1 Introduction to the project ........................................................................................................ 15 1.2 The contradictions of Amman’s Waterscapes ............................................................................. 16 1.3 Problem statement ................................................................................................................... 18 1.4 Water Sensitive Urban Design .................................................................................................. 19 1.5 CapTain Rain .......................................................................................................................... 20 1.6 Research question and objectives ............................................................................................. 21 1.7 Scope and limitations .............................................................................................................. 22 Chapter 2: Research Methods and Approaches .............................................25 2.1 Chapter structure and research flow ........................................................................................ 26 2.2 Literature review ..................................................................................................................... 26 2.3 Urban Analysis ...................................................................................................................... 26 2.4 Scenario Creation .................................................................................................................. 28 2.5 Qualitative and quantitative analysis ........................................................................................ 29 2.6 Formulation of Recommendations ........................................................................................... 32 Chapter 3: Amman’s Waterscape: Policies, Challenges, and Global Lessons ..35 3.1 National context .................................................................................................................... 35 3.2 Urbanisation in Jordan ........................................................................................................... 35 3.3 Amman’s context ................................................................................................................... 36 3.4 Climate ................................................................................................................................. 36 3.5 Climate change impacts on Jordan ......................................................................................... 38 3.6 Water ................................................................................................................................... 39 3.6.1 Water supply in Jordan .................................................................................................. 39 3.6.2 Access to water and its consumption ............................................................................... 39 3.6.3 Wastewater .................................................................................................................. 41 3.6.4 Stormwater (and the lack of it) ........................................................................................ 41 3.6.5 WSUD and the Challenges of its implementation in arid and semi-arid areas ..................... 41 3.7 Planning In Amman: Policies and Stakeholders ......................................................................... 42 3.8 Lessons learned from Pilot projects in Amman and projects from around the world ...................... 45 Chapter 4: Designing with Nature: Amman’s WSUD Toolkit ..........................51 4.1 Introduction ........................................................................................................................... 51 4.2 Defining the planning goals .................................................................................................... 52 4.3 Measures and their descriptions .............................................................................................. 52 Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman .......................65 5.1 Urban Analysis ...................................................................................................................... 65 5.1.1 Figure Ground Map .................................................................................................... 66 5.1.2 Building Classification Map ........................................................................................... 67 5.1.3 Residential Classification Map ........................................................................................ 68 5.1.4 Landuse Map ............................................................................................................... 69 5.1.5 Development Map ........................................................................................................ 70 5.1.6 Public-Private classification Map ..................................................................................... 71 5.1.7 Open Space Classification Map ..................................................................................... 72 5.1.8 Hydraulic Map .............................................................................................................. 73 5.1.9 Identification of Hotspots ............................................................................................... 74 5.2 Hotspot Analysis .................................................................................................................... 76 5.2.1 Hotspot A: Public Area .................................................................................................. 76 5.2.1.1 Description ....................................................................................................... 76 5.2.1.2 Identification of types of surfaces and areas ....................................................... 76 5.2.1.3 Conceptual design of WSUD measures for Scenarios 2 and 3 .............................. 78 5.2.1.4 Quantitative Analysis ......................................................................................... 80 5.2.1.5 Further design recommendations ........................................................................ 85 5.2.2 Hotspot B: Royal Village Project ...................................................................................... 88 5.2.2.1 Description ....................................................................................................... 88 5.2.2.2 Identification of types of surfaces and areas ........................................................ 88 5.2.2.3 Conceptual design of WSUD measures for Scenarios 2 and 3 .............................. 90 5.2.2.4 Quantitative Analysis ......................................................................................... 94 5.2.2.5 Further design recommendations ........................................................................ 96 5.2.3 Hotspot C: Residential Area ........................................................................................... 99 5.2.3.1 Description ...................................................................................................... 99 5.2.3.2 Identification of types of surfaces and areas ....................................................... 100 5.2.3.3 Conceptual design of WSUD measures for Scenarios 2 and 3 ............................. 101 5.2.3.4 Quantitative Analysis ........................................................................................ 104 5.2.3.5 Further design recommendations ....................................................................... 105 Chapter 6: Future Horizons: Concluding Insights for Amman’s Stormwater ....109 6.1 Summary of results ................................................................................................................. 109 6.1.1 Comparative analysis of ............................................................................................... 110 6.1.2 Comparative analysis of ............................................................................................... 111 6.1.3 Comparative analysis of ............................................................................................... 112 6.2 Recommended measures for the catchment .............................................................................. 113 6.3 Further Research .................................................................................................................... 113 6.4 Conclusion ............................................................................................................................ 114 Appendix .....................................................................................................116 References ...................................................................................................125 List of Figures Figure 1: On 5 February 2021, a flash flood in Jordan’s Azraq basin filled a newly constructed Managed Aquifer Recharge water harvesting structure with 65,000 m³ of fresh water in under three hours, equivalent to nearly 800,000 Jordanians’ daily consumption, showcasing a pilot initiative using local mud to decentralize drought risk management solutions through national collaborative water management efforts. ....................................................................................................................15 Figure 2: District vulnerability to Drought ....................................................................................................................16 Figure 3: District vulnerability to Floods ......................................................................................................................17 Figure 4: An urban space integrated with WSUD measures. .........................................................................................19 Figure 5: Conceptual framework of the integrated vulnerability analysis of flash floods for CapTain Rain. .......................20 Figure 6: Chapter structure and Research Flow ...........................................................................................................27 Figure 7: The three scenarios defined. ........................................................................................................................28 Figure 8: Intensity-Duration-Frequency (IDF) curves for Na’ur Station. ...........................................................................29 Figure 9: Map of Jordan with its neighbouring countries and main cities .......................................................................35 Figure 10: Monthly climatology of average minimum, mean and maximum surface air temperature and precipitation 19912020 in Jordan .........................................................................................................................................................36 Figure 11: Internal Koppen climate classification in Jordan ..........................................................................................37 Figure 12: The physio-morphological zones of Jordan ................................................................................................. 37 Figure 13: Average rainfall in Jordan .........................................................................................................................38 Figure 14: City Resilience Framework .........................................................................................................................42 Figure 15: The timeline of different plans for climate change adaptation in Jordan .......................................................44 Figure 16: Methods of integrated approach to build resilience against flash floods .......................................................45 Figure 17: Water Harvesting Systems Installation ........................................................................................................46 Figure 18: Al Zohour Green Triangle Pilot Project ........................................................................................................47 Figure 19: Integrated WSUD in inner dike districts .......................................................................................................48 Figure 20: The Benthemplein water square as temporary water storage facility, artist’s impression of the scene during a downpour (top) ; The Benthemplein after a shower (bottom left) and on a sunny day (bottom right) .......................................49 Figure 21: The cascading effect in a stormwater chain in a residential (top)and commercial (bottom) areas. The two diagrams shows how linked sequences of features can capture rainfall and release it back into the landscape. .............................51 Figure 22: The green roof will absorb and gradually release rainfall - unlike a conventional roof, which rapidly sheds the water into connecting drains. ..............................................................................................................................................53 Figure 23: Section of a typical green roof buildup .......................................................................................................53 Figure 24: (Above) Section of a typical swale with overflow into the drainage system ....................................................54 Figure 25: (Right) A vegetated swale with geo-textile to permeate as well as convey stormwater runoff ..........................54 Figure 26: How a raingarden works ...........................................................................................................................55 Figure 27: A series of stormwater planters collecting water between two structures integrated into the landscape, creating a drainage chain to reduce runoff volumes and rates, ....................................................................................................56 Figure 28: Section of RWH system ............................................................................................................................57 Figure 29: RWH in a garden for irrigation ................................................................................................................... 57 Figure 30: Typical section of a permeable pavement ...................................................................................................58 Figure 31: Example of a permeable pavement in a parking lot ....................................................................................58 Figure 32: Spring in the Highline in New York. A corridor of biodiversity in a dense urban setting brings life to this post industrial district. .................................................................................................................................................................59 Figure 33: (Top) - The slope of the base of the pond is not even, giving rise to a complex mosaic of conditions. .............60 Figure 34: (Bottom) - A retention basin may include a forebay area to encourage sedimentation and an outflow for excess water. .......................................................................................................................................................................60 Figure 35: (Left) Detention pond (dry), Gelsenkirchen, Germany ................................................................................61 Figure 36: (Right) Detention pond (wet) in Tanner Springs Park, Portland, Oregon, USA ...............................................61 Figure 37: (top) - The Tåsinge Plads combines the technical requirements of storm water management with the neighbourhood’s desire for a green oasis and a local meeting space. ......................................................................................... 62 Figure 38: (bottom) - Part of the Tåsinge Plads that provides seating around green areas ..............................................62 Figure 39: The division of Amman into catchments, flow paths of flood water and flood risk index based on topography. 65 Figure 40: Figure Ground Map of the catchment ........................................................................................................66 Figure 41: Graph showing the built and unbuilt areas in percentage of the total catchment area. .................................66 Figure 42: Building classification based on function ....................................................................................................67 Figure 43: Graph showing the share of different building classifications. ......................................................................67 Figure 44: Classification of residential buildings based on typology .............................................................................68 Figure 45: Graph showing the share of different residential classes..............................................................................68 Figure 46: Landuse classification based on function ....................................................................................................69 Figure 47: Graph showing the share of Landuse. ........................................................................................................69 Figure 48: Classification of residential buildings based on typology .............................................................................70 Figure 49: Graph showing the share of developed and undeveloped areas. ................................................................70 Figure 50: Classification of land based on ownership. ................................................................................................. 71 Figure 51: Graph showing the share of Landuse. ........................................................................................................71 Figure 52: Classification of open spaces based on typology ........................................................................................72 Figure 53: Graph showing the share of developed and undeveloped areas. ................................................................72 Figure 54: Hydraulic map showing sinks and flow paths ..............................................................................................73 Figure 55: Identification of hotspots ...........................................................................................................................74 Figure 56: The Risk - Potential matrix for all the hotspots .............................................................................................75 Figure 57: This map shows an overlap of the hydraulic map showing the flows and sinks on the map showing different functions of buildings and open spaces for the Hotspot A - Public Areas. ............................................................................76 Figure 58: Map of Scenario 1 - The different surfaces within the hotspot as identified by satellite images in the existing conditions. ........................................................................................................................................................................77 Figure 59: Map of Scenario 2 - Conceptual design of measures in public areas ...........................................................79 Figure 60: Map of Scenario 3 - Conceptual design of measures in public and private areas .......................................... 80 Figure 61: Runoff volumes for the three scenarios .......................................................................................................83 Figure 62: Runoff rates for the three scenarios ............................................................................................................84 Figure 63: 10@Hoyt Apartments is focused on the activation of water in the landscape. Water flows through Cor-Ten steel channels from the rooftops into detention beds filled with river stones. The area, though not entirely unsealed, has green elements combined with open seating and integrates stormwater into the landscape in an artistic manner. .........................86 Figure 64: The royal village project in its current “greenfield” state, overlaid by a layer of hydraulics showing sinks within the hotspot .....................................................................................................................................................................88 Figure 65: The royal village project masterplan as proposed by the architects Alnasser + Partners.................................89 Figure 66: Street E section of a 15m wide road with a bioretention area acting as a buffer between the main street and the Royal village project residential area ..........................................................................................................................90 Figure 67: Street F section of a typical 12m wide road with a bioretention area acting as a median between two lanes of traffic. ...........................................................................................................................................................................91 Figure 68: Recommended measures for scenario 2 .....................................................................................................92 Figure 69: Recommended measures for scenario 3 including residential areas .............................................................93 Figure 70: Runoff volumes for the four scenarios .........................................................................................................94 Figure 71: Runoff rates for the four scenarios ..............................................................................................................95 Figure 72: A layout of Tasinge Plads depicting the various zones and multi-functionality and a view of one of the detention basins ......................................................................................................................................................................97 Figure 73: A view of the Tanner Springs Park in Portland, Oregon, USA. .......................................................................98 Figure 74: Interaction between the stormwater runoff and recreational space in the Tanner Springs Park. .......................98 Figure 75: This map shows an overlap of the hydraulic map showing the flows and sinks on the map and showing different functions of buildings and open spaces for the Hotspot C - Residential areas. ...............................................................99 Figure 76: Map of Scenario 1 - The different surfaces within the hotspot as identified by satellite images in the existing conditions. ......................................................................................................................................................................100 Figure 77: Map showing the layout of different street types and surfaces as per the conceptual design for scenario 2. ..101 Figure 78: Street type A - section depicting the division of high speed traffic from the inner lanes through the integration of swales, and a bigger bioretention area in the median of the road. ............................................................................102 Figure 79: Street type B - section depicting the division of vehicular traffic from the pedestrian paths through the integration of swales, and a bigger bioretention area in the median of the road. .............................................................................102 Figure 80: Street type C - This commercial street has a two way traffic lane in the middle and 3m wide parking spaces to the sides interspersed with raingardens that separate the pedestrian pathways in front of the shops. .................................. 102 Figure 81: Street type D - section of the inner residential lanes where the traffic is separated from the pedestrian zones though swales that have shady trees to provide a canopy and buffer noise.. .........................................................................103 Figure 82: Map showing the layout of rooftops with RWH as per scenario 3. ..............................................................103 Figure 83: Runoff volumes for the three scenarios .....................................................................................................104 Figure 84: Runoff rates for the three scenarios ..........................................................................................................105 Figure 85: This design aims to create more opportunities for capturing rainwater and then slowly releasing it or using it within the garden. ............................................................................................................................................................107 Figure 86: Stormwater planters have been used to create a sheltered outdoor space next to the house. Bench seating has been attached to the walls of the planter. Water from the roof travels through the planters into a pond which overflows into a garden swale. ....................................................................................................................................................................107 16 1.3 Problem statement Even though arid and semi-arid regions often face water shortages and infrequent low rainfall, recent floods in these areas have demonstrated that flooding can be exceptionally severe and life-threatening. However, flooding still needs to be more adequately understood as a natural hazard in these environments, and its management must confront challenges, some of which are specific to arid and semi-arid zones (Nabinejad and Schüttrumpf 2023). Urban hydrology is increasingly stressed by urbanization and climate change. Urbanization is proven to affect the hydrological responses of natural catchments. It reduces infiltration, base flow and lag times, and at the same time, stormwater flow volumes, peak discharge, frequency of floods and surface runoff are dramatically increased (Du et al., 2012). In the future, Amman, Irbid, and Zarqa, Jordan’s major cities crucial to the economy, will face heightened vulnerability to hazards due to climate change. These cities are expected to become drier while also encountering more intense precipitation events, leading to heightened flood risks. The built-up areas exposed to pluvial flood hazards have expanded and are projected to keep growing across all climate scenarios, particularly impacting low-income households (The World Bank Group, 2022). Looking over time and due to climate change impacts and drought events, the extreme events of floods and droughts have been exacerbated recently. Based on the third national report to UNFCCC, Jordan is expected to have a warmer and drier climate with a potential increase in air temperatures from +2.1 degrees Celsius to +4 degrees Celsius and a decrease in the annual rainfall from 15% up to 35 % in 2100 (MoEnv, 2014). Despite the governmental efforts to manage the country’s limited water resources and the ongoing search for alternative sources of supply, the adopted political, financial and technical responses are not able to bridge the supply and demand gap. Several of the inspected adaptation measures include desalination, wastewater and greywater recycling, stormwater collection and efficient water use. However, the existing conventional stormwater systems lack the flexibility to accommodate expanding urbanization and climate change impacts effectively and efficiently (Gammoh & Shamseldin, 2019). “The existing conventional stormwater systems lack the flexibility to accommodate rapid changes in urbanization and climate that have exacerbated droughts and floods in Jordan.” Chapter 1: Amman’s Urban Waters: Issues and Opportunities 17 1.4 Water Sensitive Urban Design While these issues seem unrelated to each other, a common solution can be found in the circularity of stormwater. Going back to the natural water cycle and managing stormwater as close to the source as possible would not only help with flood relief, but also keep the rainwater from being polluted as it runs over various impermeable surfaces, either by seeping directly into the groundwater or by being collected in storage tanks for reuse (Urban Design Lab 2023). The aim is to keep these solutions as natural as possible, meaning, no major constructions and find a resource-efficient way to achieve these goals. Water Sensitive Urban Design (WSUD) is a holistic approach to urban planning and design that integrates the management of the whole urban water cycle into the process of land use and urban development (Elzein et al., 2022; Sharifian et al., 2022). In WSUD, urban water is managed so that it minimizes the negative urbanization impacts while maximizing the economic, social, and environmental benefits, thus providing more healthy and livable cities (DEWNR, 2013). Water Sensitive Urban Design (WSUD) integrates water management, urban design, and landscape planning by encompassing the entire urban water cycle and integrating water management functions with urban design principles (Hoyer, J., et.al, 2011). It provides the link between integrative approaches of stormwater management and urban design and comprehensively addresses all facets of the urban water cycle, with a particular emphasis on stormwater management, recognizing its dual role as a valuable resource and as a means to protect receiving waterways (Melbourne Water, 2005). Decentralized stormwater management systems are enhanced when integrated with urban design requirements. Consequently, WSUD is primarily applied in urban stormwater management, aiming to emulate a natural water cycle and enhance urban amenity. As outlined in the “Urban Stormwater: Best Practice Environmental Management Guidelines” by the Victorian Stormwater Committee (1999), the objectives of WSUD in stormwater management and planning are as follows: • Protection of natural water systems within urban developments. • Improvement of water quality through filtration and retention methods. Reduction of stormwater runoff and peak flows via local detention and retention strategies and minimizing impervious surfaces. • Decrease in drainage infrastructure and associated development costs, while enhancing sustainability and urban amenity. • Integration of stormwater management into the landscape by creating multi-use corridors that enhance the visual and recreational appeal of urban areas (Hoyer et al. 2011). Figure 4 illustrates how an integrative approach and resource management would look in an urban space by reversing biodiversity loss caused by urbanization (Urban Design Lab, 2024). Figure 4: An urban space integrated with WSUD measures Source: Urban Design Lab , 2024 18 1.5 CapTain Rain Several studies have been done on water sensitive urban design, the sponge city concept and low impact development for huge metropolitans around the world. These have led to the development of several pilot projects and international cooperation to make cities resilient to extreme rainfall events. CapTain Rain is a similar project being developed by the German and Jordanian cooperation that aims to capture and retain rainfall for potential reuse in Jordan. Despite their destructive power, heavy rainfall events play a key role in the hydrological cycle of (semi-)arid regions, as they replenish scarce water resources. In the face of increasing drought risk and water scarcity, it is therefore important to capture and retain rainfall (ISOE GmbH 2024). In this context, CapTain Rain is investigating measures for the diversion, retention and utilization of heavy rainfall and for improving heavy rainfall preparedness of the local population. The study is conducted along an urban-rural gradient and includes Amman and Petra. In addition to traditional methods of stormwater retention, storage and utilization, the concept of multifunctional land use for heavy rainfall prevention is explored in urban areas (CapTain Rain 2024). Within the trans-disciplinary research project CapTain Rain, the German and Jordanian project partners aim to help improve current methods and tools for flash flood prediction and prevention. For this purpose, the driving factors of flash floods in Jordan’s wadi systems will be analysed and the complex interactions between climate and land use changes and hydraulic engineering measures will be unraveled. Based on vulnerability analyses and engineering solutions for water collection and drainage during heavy rainfall events, measures to protect the population will be identified. Climate services (e.g., flash flood risk maps, early warning systems, recommendations for heavy rainfall risk prevention) will be developed in close collaboration with Jordanian stakeholders and practice partners, considering scientific as well as local practical knowledge as shown in Figure 5. The study areas include the capital Amman in the metropolitan region and the more rural region Wadi Musa around the UNESCO World Heritage Site Petra. Both regions have been heavily affected by flash flood events in the past (CapTain Rain progress report, 2023). The trans-disciplinary research methodologies employed by CapTain Rain facilitate a comprehensive analysis of flash flood hazards and prevention strategies, effectively bridging the gap between scientific knowledge and practical climate change adaptation measures. Specifically, CapTain Rain will: 1. Examine the social-ecological drivers of flash floods in Jordan’s wadi systems and unravel the complex interactions between climate and land use changes, improving the simulation and prediction of flash flood events. 2. Evaluate the social-ecological risk of flash floods through an integrated vulnerability analysis, considering spatial exposure, sensitivity, and adaptive capacity. 3. Develop climate services to support flood-related decision-making, utilizing stakeholder dialogs and participatory approaches. 4. Identify effective measures to enhance the adaptive capacity of local communities, including technologies and methods for capturing and retaining water from heavy rainfall and preventing damage (CapTain Rain 2024). This thesis is based on the data retrieved through Hamburg Wasser for the project CapTain Rain, which is one of the partner companies and chief stakeholder in the project. The data is primarily site observations by the Hamburg Wasser teams on site, landuse data from GAM and hydrological analysis done by other stakeholders as part of this research. Figure 5: Conceptual framework of the integrated vulnerability analysis of flash floods for CapTain Rain. Source: (CapTain Rain 2024) Chapter 1: Amman’s Urban Waters: Issues and Opportunities 19 1.6 Research question and objectives In arid and semi-arid regions, adopting Water Sensitive Urban Design (WSUD) is a cost-effective approach to managing scarce water resources. It facilitates efficient water use, creating green open spaces with treated wastewater and native plants, addressing extreme heat, providing urban cooling, and offering ecological, social, and amenity benefits. WSUD practices also enhance stormwater infiltration and groundwater recharge for drought adaptation. Challenges include health risks, public acceptance, limited experience, and the need for substantial spaces in densely populated areas, along with institutional barriers (Costa et al., 2015). Therefore, this research aims to explore water-sensitive urban design strategies that best suit a dense urban area in Amman, Jordan to tackle stormwater challenges, both in terms of flash floods and water shortages. While these studies cover the aspects of stormwater management in various climates, contextualisation of these measures to semi-arid and arid regions is a fairly new and emerging concept. On one hand, decentralized methods of stormwater management are being explored at the household level and on the other, mega projects of desalination and wastewater recycling are being given high investments. Therefore, this research aims to explore middle-ground, medium-scale, and low-impact development strategies and to investigate their efficiency. The scope, however, is limited to the implementation of WSUD measures in a dense urban area in Amman. This would be done by creating 3 distinct scenarios, each with defined boundary conditions, and different strategies for stormwater management, and ultimately comparing the results. Therefore, the objectives of this research are: • To identify the hotspots in a catchment area, or places of high risk and high potential. • To define the planning goals to be achieved by certain selected WSUD measures. • To develop strategies for different scenarios and compare their results. • Finally, to create a list of recommendations for future development in this area. “What combination of Water Sensitive Urban Design strategies can be implemented in a dense urban area in Amman, Jordan, to overcome stormwater challenges, both in terms of protection during flash floods and providing an additional source of water during dry periods?” 20 1.7 Scope and limitations The scope of this research is limited to the analysis of one catchment in the district of Marj Al Hamam with an area of 1317 hectares. Since access to the site was not possible, most of the data gathered is from satellite imagery and data obtained from the Greater Amman Municipality or GAM through the project CapTain Rain and Hamburg Wasser as well as published reports of previously conducted surveys. This raw GIS data has not been published yet and hence is referenced only as HW 2024, from where it is sourced. However, it has been added to and further improved by Google Maps and ArcGIS satellite imagery. Due to this many assumptions about the types of surfaces have been made, as explained in the further chapters. It should also be noted that the areas taken from GIS for the various scenarios have a slight error margin, therefore the calculated values of areas and volumes are an estimation and should not be considered exact. To further limit the scope of this project, a detailed analysis will be done of selected hotspots and not of the entire catchment area. These hotspots will be selected based on their typology and keeping in mind that they are representative of the different neighbourhoods of the catchment for future scalability. The measures and strategies taken into account are designed at a conceptual level according to a study of the area available for implementation. Further analysis of the feasibility of these measures needs to be done with the involvement of the various stakeholders. Additionally, further research needs to be done on the application of these measures in arid climates and the respective native plantations. A guide to native plants has been published (Guide to Species Selection for Amman Public Open Spaces 2021) and referred to in the following chapters. The volume estimations are done based on German standards from the DWA as the information on Jordanian stormwater management and urban drainage regulations was not available. The idea is to conduct an estimation of the effects of WSUD measures in this particular context, to create further scalable recommendations. The volume estimations also need to be further calculated on software like STORM or SWMM for a more precise design simulation. Chapter 1: Amman’s Urban Waters: Issues and Opportunities 21 22 Chapter 2: Research Methods and Approaches 23 Chapter 2 Research Methods and Approaches The reason for choosing the context of Amman was driven by a curiosity of exploring the flooding patterns in desert climates, something that is not a popular perception or understanding. Even though the annual precipitation in arid regions is low, stormwater management becomes especially vital for the purpose of rejuvenating the ground water Table and maintaining natural water flow cycles even in densely urbanized areas. The research done in this field is limited to South Australia and the USA which may have similar climate contexts but vary widely in urban and demographic contexts. Inspiration and experience were gained during the involvement with Hamburg Wasser, one of the stakeholders of the research project CapTain Rain and subsequent contribution to it. This chapter elaborates on the various research methodologies used for this thesis. It explains the methods in detail in the following section, outlines the sourcing and quality of data and the approaches of analysing it. It also provides a basic outline of each of the chapters in this thesis and illustrates how they are connected and what is the research flow. Though this was an iterative process, with a lot of back and forth between sections, a linear research flow was managed and followed to create a storyline. The interconnection between chapters and the flow of the master thesis research is illustrated in Figure 6. 24 2.1 Chapter structure and research flow Chapter 1 - Amman’s Urban Waters, provides an introductory insight into the relevance of WSUD in Amman. It discusses how urbanization and climate change have exacerbated the conditions of flash floods and water scarcity in Amman, thus defining the problem. It further elaborates on the need for WSUD and explains the basic principle of blue-green infrastructure and its positive impacts on the urban water cycle of any place. Further, this chapter also discusses the contribution of the research project CapTain Rain. Finally, it is summarised by a statement of the research question and objectives and the scope and limitations of the project. Chapter 2 – Research methods and approaches explain the methodology and research flow as well as the details concerning obtained data. It briefly outlines the contents of each chapter and how they are interconnected. Further, the creation of the scenarios is explained here, and the rationale behind them. Finally, this chapter contains the most crucial elements of the comparative analysis – how it is conducted qualitatively and quantitatively, citing the formulas used and the rationale behind them. The third chapter on Amman’s Waterscapes outlines the status quo of Jordan and Amman in terms of background, climate, policies and stakeholders. Here the issues and opportunities of Amman’s urban waters are detailed. This forms the basis of finding research gaps and contextualises the site. It is concluded by lessons learnt from case studies that would help in building the recommendations for further development in the area. Chapter 4 - Designing the WSUD Toolbox summarises the planning goals that set guidelines for selecting and implementing measures. Further, the various selected measures are detailed in a format to better understand the processes and technologies involved. The format is also intended to be used in stakeholder meetings and workshops, essentially simplified to a level of easy understanding. This toolkit will be used for the conceptual design of the scenarios in the next chapter. Chapter 5 – Scenarios in focus, is where the bulk of the analysis is conducted, beginning from the urban analysis of the site to select the relevant hotspots. These hotspots are then further detailed, and different types of surfaces and their areas are obtained. The next step is to create 3 distinct scenarios with a conceptual design of the measures from the toolkit. Further, these scenarios are compared based on the calculations of peak runoff volumes and peak runoff rates, as well as the planning goals achieved by them. Lastly, Chapter 6 – Future Horizons outlines the recommendations that are an outcome of the comparative analysis conducted in the previous chapter. The section of the discussion addresses certain challenges and the conclusions drawn from the research and offers the possibilities for further research. 2.2 Literature review One key methodology used to refine this research is a literature review. To get a deeper understanding of the context, this section delves into summarizing reports and publications that describe the background of Jordan as a country and the challenges it faces in the context of water. It further describes the capital city of Amman, its climate, topography and urban hydrology. It also looks into policies and frameworks for further urban development and the stakeholders responsible for the same. Some stormwater management projects that have been researched are mentioned here as well. Finally, some case studies of implemented stormwater pilot projects by the UN Habitat are observed and lessons learned from applied WSUD in Rotterdam are summarised. 2.3 Urban Analysis The second methodology used is conducting an urban analysis of a selected catchment area. The mapping of different typologies of surfaces and materials is done based on satellite imagery from Google Maps, Open Street Map and ArcGIS satellite imagery. The data collected is synthesized in QGIS, separating the various layers of the urban area like built and unbuilt, ownership of land, land use based on function, open space and flow of stormwater. The hydrological maps are based on the heavy rainfall event of 2019 and are taken directly from HW, 2024. Separating these layers and then overlapping them with the hydrological data leads to the identification of hotspots or areas that are at high risk and have a good potential for implementing WSUD measures. Further, some hotspots will be selected for an indepth analysis that best represents the catchment area and represent certain distinct urban typologies. Chapter 2: Research Methods and Approaches 25 Research question and objectives Research methods and approaches Water scarcity vs Flash Floods WSUD Scenario formation Qualitative and quantitative aspects Ammans’s waterscapes Context, climate, urban waters, policies and stakeholders Lessons learned from case studies WSUD Toolkit Defining planning goals Infocards Analysis Urban Analysis Hotspot selection Conceptual design Comparative Analysis Conclusive insights Recommendations for future development Further research and Conclusions Figure 6: Chapter structure and Research Flow Source: Author Chapter 1 Chapter 2Chapter 3Chapter 4Chapter 5Chapter 6 32 Chapter 3: Amman’s Waterscape: Policies, Challenges, and Global Lessons 33 Chapter 3 Amman’s Waterscape: Policies, Challenges, and Global Lessons 3.1 National context The Hashemite Kingdom of Jordan, referred to as Jordan, is situated in the rocky desert region of the northern Arabian Peninsula. It shares borders with Syria to the north, Iraq to the northeast, and Saudi Arabia to the east and south, spanning a total area of 89,318 square kilometres as in Figure 9. As of 2019, Jordan has a population of 10.5 million people, with a significant concentration residing in and around the capital city, Amman (UN Habitat 2022). Jordan is renowned for its stability in a turbulent region. Throughout its history and particularly since the onset of the Syrian crisis, it has welcomed large numbers of refugees. Jordan has the second-highest number of refugees per capita globally, with 89 refugees per 1,000 inhabitants (UN Habitat 2022). Jordan’s population nearly doubled between 2004 and 2015, influenced by the political situations in Iraq and Syria. As one of the youngest countries globally, around 63 % of its population is under 30. This demographic trend necessitates long-term resource planning to meet the future needs of the growing population (UN Habitat 2022). 3.2 Urbanisation in Jordan Jordan is among the 50 most urbanized countries globally, with 90.3 % of its population living in urban areas. The country is experiencing rapid urban growth, with an annual population growth rate of 2.3 % (2019) and a population density of 118.9 people per square kilometer. Over the past two decades, Jordan’s built-up area has doubled to 1,500 km², with urban areas covering 909 km². This expansion, at 1 % per year (15 km²), threatens agricultural land and infrastructure development (UN Habitat 2022).Nearly three-quarters of Jordan consists of a barren plateau in the east and southeast. The western and northwestern regions are the most fertile, habiTable, and urbanized, where most of the population resides. The southern governorates are sparsely populated, with only 8 % of the population, and have lower infrastructure development, except for Aqaba city, due to the challenging landscape, resource availability, and climate (UN Habitat 2022).. Figure 9: Map of Jordan with its neighbouring countries and main cities Source: (Vidiani 2011) 34 3.3 Amman’s context Amman Governorate, home to Jordan’s capital city Amman, is the largest in terms of population. Located in the northwestern region of Jordan, it has a central geographical position among the Kingdom’s governorates. It borders Zarqa Governorate to the north and northeast, Al Balqaa and Madaba to the west, Karak and Ma’an to the south, and shares an international border with Saudi Arabia to the east. The governorate is about 750 above sea level and covers an area of 7,579 km², accounting for 8.5 % of Jordan’s total area (Ministry of Interior Jordan 2024). As of 2020, Amman Governorate’s population constitutes of 42 % of Jordan’s total population, which is equal to 4.5 million, and most of this population -around 3.8 millionresides within Greater Amman Municipality (GAM) (UN Habitat, 2022). Amman is the most urbanized governorate, with 97.22 % of its population living in urban areas. It serves as the political, economic, and cultural hub of Jordan, hosting 48 % of the country’s economic and commercial institutions, as well as most of the state’s institutions, governmental departments, and the Parliament (Ministry of Interior Jordan 2024). 3.4 Climate Jordan’s climate is predominantly arid and semi-arid, with an average surface temperature ranging from 10 °C to 25 °C. Precipitation varies internally due to topography, with the rainy season typically spanning from October to May and peaking in January as seen in Figure 10. Three ecological zones characterize Jordan: the Jordan Valley, experiencing warm winters and hot summers with 100-300mm of rainfall; the Western Highlands, with higher rainfall (300-600mm) and fluctuating temperatures; and the arid Badia region, with annual rainfall below 50mm and wide temperature variations as shown in Figure 12 and 13 (Jordan Red Crescent 2022). The internal Koppen classification of Jordan’s climates provides further detail, as illustrated in Figure 11. Despite its relatively small size, Jordan boasts a diverse terrain and landscape, which is typically associated with larger countries. This diversity is influenced by factors such as geography, history, geopolitics, and the scarcity of natural resources. Although Jordan covers an area of 89,320 km², three-quarters of its territory is desert. However, the landscape exhibits remarkable diversity over short distances. Five main physiographic regions, aligned in a north-south direction, characterize Jordan: the tropical desert in the central Ghor or rift valley, escarpments and mountain highlands east of the Ghor, arid plains, the Badia, and the Azraq and Wadi Sirhan depression. These regions correspond to five major morphological zones (United Nations Development Programme and GEF 2022). Jordan has three distinct ecological zones: 1. Jordan valley which is a narrow strip below the sea level and has warm winters (19-22 °C) and hot summers (38 - 39 °C) with an average rainfall between 100-300mm 2. The western highlands where rainfall is relativeFigure 10: Monhtly climatology of average minimum, mean and maximum surface air temperature and precipitation 1991-2020 in Jordan Source: (World Bank 2021) Chapter 3: Amman’s Waterscape: Policies, Challenges, and Global Lessons 35 Figure 11: Internal Koppen climate classification in Jordan Source: (Albadaineh, 2022) Figure 12: The physio-morphological zones of Jordan Source: (United Nations Development Programme and GEF 2022) 36 ly high (300-600mm) per year and temperatures range between 9 -13 °C in the winter to 26 – 29 °C in the summer 3. The Badia, an arid and semi arid island to the east that covers aout 80 % of the land where the annual rainfall is below 50mm and temperatures range between 14 -16 °C in the winter to 35 -37 °C in the summer (Jordan Red Crescent 2022; GEF 2014). 3.5 Climate change impacts on Jordan With very limited water sources, Jordan is the second most water-scarce country in the world, with annual renewable water resources of less than 100 m³ per person (UNICEF 2019). Heavily reliant on external water resources, this scarcity has caused tensions with neighbouring countries. The large influx of refugees has further strained Jordan’s ability to meet its domestic water needs (UN Habitat 2022). Though not a major contributor to climate change, Jordan is among the countries Figure 13: Average rainfall in Jordan Source: (Ababsa 2013) Chapter 3: Amman’s Waterscape: Policies, Challenges, and Global Lessons 37 most affected by it. The nation is experiencing rising temperatures, erratic rainfall, reduced water availability (both underground and surface), and a higher likelihood of heatwaves, flash floods, droughts, and landslides (LandLinks 2018).Based on future projections and climate forecasts, Jordan is expected to experience significant climate change impacts according to various greenhouse gas concentration pathways. The main insights from the comprehensive climate change projections exercise conducted in the 4NC are summarized in Table 4. These trends outline the anticipated future climate in Jordan through 2100 (United Nations Development Programme and GEF 2022). 3.6 Water 3.6.1 Water supply in Jordan Due to its arid climate and limited water resources, Jordan is ranked second globally in terms of water scarcity and has the lowest per capita water availability. Political instability in the region has exacerbated the issue, leading to a decrease in trans-boundary surface water resources over time. In the long term, the country is expected to receive approximately 8.2 billion m³ of rainfall annually, with only 5 % recharging groundwater aquifers and 2-3 % transforming into direct flood flow. The majority of rainfall (92-93 %) is lost to evapo-transpiration. Consequently, developed surface water resources cannot meet water demand, necessitating reliance on groundwater and unconventional sources such as treated wastewater. Main surface water resources include water stored in dams and water from the Yarmouk River and the Tiberia Conveyor (Peace Water). These resources are primarily located in basins with relatively higher rainfall, such as the Yarmouk basin (shared with Syria) and side-branches of the Jordan Valley, where dams have been constructed to supply water for various uses. Some dams receive treated wastewater mixed with rainfall water for irrigation in the Jordan Valley (United Nations Development Programme and GEF 2022). Water supply for Amman Governorate originates from various sources, with the majority of drinking water traveling distances of 125 to 325 km, leading to increased supply costs (Ministry of Environment Jordan 2020). Unlike other areas relying on groundwater, west Amman City receives water from the King Abdullah Canal, Jordan’s largest canal system, serving 40 % of the governorate’s water needs post-treatment (Ministry of Environment Jordan 2020; UN Habitat 2022). The completion of the Disi aquifer project in 2013 contributed significantly, providing approximately 107 million m³ of drinking water annually to Amman Governorate and neighbouring regions (UN Habitat 2022). Despite these efforts, there are challenges in water access through the public network, with non-revenue water accounting for 50 % of total consumption, especially noTable in Amman Governorate (MoWI, 2016). Water utilities in Amman, southern, and northern Jordan have successfully reduced water losses through USAID-backed initiatives, aiming to save 7 million m³ of water by 2020, equivalent to the needs of 190,000 people yearly (USAID, 2020). 3.6.2 Access to water and its consumption Miyahuna, a state-owned private company, operates Amman’s piped water system under the regulation of the Water Authority of Jordan (WAJ) (Klassert et al. 2015). Despite approximately 98 % of households being connected to this system, a 40 % increase in water demand due to population growth has led to intermittent supply issues (GAM and Rockefeller 2017). As a result, households often store water in rooftop or basement tanks, with capacities varying based on income levels. Additionally, an estimated 37 % of water is lost as non-revenue water (AECOM 2021). Households in Amman pay for piped water and wastewater based on an increasing block tariff, with costs amounting to 1 % to 1.5 % of household incomes. However, due to perceived health risks, many households refrain from using piped water for drinking, opting for alternative sources such as private tanker operators, water stores, or retail bottles (UN Habitat 2022). Approximately 98 % of households in Amman Governorate are connected to the piped water system, but only 14.2 % of the population uses the public network for drinking water (Klassert et al. 2015). The majority, 85.8 %, either rely on water filters or purchase mineral water due to the perceived low quality of publicly supplied water. Regarding refugees, 99 % of Syrian households in Amman have access to a piped water source (UN Habitat 2022). Being one of the most water-scarce nations globally, Jordan highly values water as a precious commodity. With only 90 m³ of water available per person annually in comparison to the global benchmark of absolute water scarcity of 500m³ (Jordan Red Crescent 2022), projections suggest this allocation may decrease further to 60 m³ by 2040 (International Trade Administration 2024). Renewable water resources barely meet half of the country’s total consumption, resulting in frequent interruptions. Several factors worsen Jordan’s already delicate water situation, including low rainfall, rising demand due to population growth and economic development, unsustainable agricultural and groundwater pumping practices, non-revenue water losses, limited water resources, deteriorating water quality, and the impacts of climate change (International Trade Administration 2024). 38 Trend Description A warmer climate For the 2070-2100 period the minimum air temperature is extremely likely to increase by 1.2 °C [+0.6 °C to +2.9 °C] according to RCP 4.5 and by 2.7°C [+2.1 °C to +4.5 °C] according to RCP 8.5. Similarly, the maximum air temperature is very likely to increase by 1.1 °C [+0.7 °C to +1.7 °C] according to RCP 4.5 and by 3.1 °C [+2.6 °C to +3.7 °C] according to RCP 8.5. A drier Climate For the 2070-2100 period the country is likely to become drier, as the precipitation tends to decrease by 15.8 % [-7.1 % to -31.3 %] according to RCP 4.5 and by 47.0 % [-23.3 % to -57.5 %] according to RCP 8.5, taking into account that some zones are predicted to receive more precipitation, with a maximum increase of 19 %, according to RCP 4.5, while the whole country is projected to become drier according to RCP 8.5. The significant precipitation decrease is projected to be most likely at the western part of the country, while predicted potential increases are likely to occur in the southern arid zones. Insignificant wind changes Wind speed forecasts didn’t indicate significant changes; however, the country is about as likely as not to be subjected to wind bloom events exceeding 12 m/s. Mild decrease in relative humidity For the 2070-2100 period the relative humidity is likely to decrease by 3 % [-2.5 % to -3.3 %] according to RCP 4.5 and by 7.2 % [-6.0 % to -7.8 %] according to RCP 8.5. In all scenario cases, the Northern Badia is likely to be subjected to a decrease in relative humidity at a higher rate than other parts or regions. More drought, a contrasted water balance Drought SPI indicators reveal an increasing trend of drought in the northern part of the country reaching a maximum of 50 % using RCP 4.5 and 93 % using RCP 8.5. The magnitude of drought events is increasing with time, from normal to severe, while the duration of the droughts is likely to become longer, over 3 consecutive years, using RCP 4.5 and more than 5 years using RCP 8.5. High crop water demand For the 2070-2100 period, the potential evapo-transpiration is very likely to increase by 5.8 % [+4.7 % to +6.9 %] according to RCP 4.5 and by 11.1 % [+8.1 % to +15.3 %] according to RCP 8.5. In the worst-case scenario, the evapo-transpiration for the whole country is very likely to increase by 15 % above the baseline scenario, thus setting the systems under pressure of greater water demands. Intense precipitation and potential floods The is no significant sign of heavy rain days (more than 20 mm), however future trends indicate the probability of occurrence of potential intense precipitation, that seems to decrease with time, especially at RCP 8.5 as compared to RCP 4.5. On other hand, the severity is variable by location and tends to become more likely than not intense during the mid-21st century and reduces by the end of the 21st century. More intense heat waves Future predicted heatwave events are more severe in terms of duration and magnitude, where the probability of occurrence increases to an average of 120 % by 2100 (ranging from 54 % to 398 % based on spatial location) using RCP 4.5, and about a threefold increase (ranging from 1.5 to 9.0 times, based on spatial location) using RCP 8.5. Thus, it is very likely that more severe threats are expected in terms of heatwave exposure intensity and duration, especially in the highlands regions of Madaba, Shoubak and QAI Airport during the months of March, April and May. Table 4: Trends and their descriptions that indicate the expected future of climate in Jordan until 2100. Source: Adapted from (United Nations Development Programme and GEF 2022) Chapter 3: Amman’s Waterscape: Policies, Challenges, and Global Lessons 39 3.6.3 Wastewater As previously mentioned, reclaimed water is highly valued by the Jordanian government for its contribution to the country’s water resources, as emphasized in Jordan’s Water Strategy 2008-2022. The strategy states that wastewater should not be treated as waste but rather collected and treated to standards that allow for its unrestricted use in agriculture and other non-domestic purposes, including groundwater recharge. Over 70 % of Jordan’s population is connected to the sewage system, with raw wastewater directed to 34 wastewater treatment plants (WWTPs). The most common treatment method is the activated sludge process, which accounts for 60 % of wastewater treatment. The As-Samra Wastewater Treatment Plant, a large-scale facility, processes more than 70 % of the country’s total wastewater, amounting to 170 million m³ in 2020 (United Nations Development Programme and GEF 2022). 3.6.4 Stormwater (and the lack of it) The Hashemite Kingdom of Jordan is facing severe water scarcity, ranking among the top four most arid nations globally. This scarcity poses a significant challenge to growth and development, as available water resources per capita are decreasing while demand is rising. The water deficit is exacerbated by both economic and population growth. To manage water consumption, water is distributed only once a week to citizens and businesses, who then store it in tanks. Currently, municipal water usage, including in the Greater Amman Municipality (GAM), relies primarily on groundwater sources. If the supply remains unchanged, per capita domestic consumption is projected to drop to 90 m³ per person per year by 2025, categorizing the country as experiencing an absolute water shortage that could hinder economic growth and threaten public health (GAM 2019). The national government of Jordan, specifically the Ministry of Water and Irrigation, is responsible for water supply, pumping, and delivery, as well as wastewater treatment in Amman. These systems are under significant strain due to the growing refugee crisis and the influx of refugees. Groundwater levels have significantly declined, indicating unsustainable usage. Despite improvements in water-supply infrastructure, a critical imbalance between supply and demand persists. From 2011 to 2015, water demand increased by 40 % (Hashemite Kingdom of Jordan, 2013). Climate change further aggravates these issues, potentially reducing precipitation. Despite the overall decrease in precipitation, the frequency of severe storms leading to heavy rainfall has increased, causing frequent flash floods in Amman. In 2015, a 30-minute downpour resulted in a severe flash flood, causing fatalities, property damage, flooded streets, and people being trapped in their cars and homes. Events like these have become more frequent like the flash flood in 2018 and 2019 consecutively caused a lot of damage to the city’s infrastructure. Therefore, effective stormwater management is a primary focus of the Resilience Strategy (GAM 2019). 3.6.5 WSUD and the Challenges of its implementation in arid and semi-arid areas Here is a brief explanation of the different terminology used to describe this planning approach: Sustainable Drainage Systems (SuDS): Used mainly in the UK and Ireland, SuDS manage surface water close to its source by mimicking natural processes. They address water quality, quantity, and amenity through various techniques for attenuation, infiltration, flow control, and water treatment (Stephenson 2013). Water Sensitive Urban Design (WSUD): A global approach to urban planning that integrates sustainable water management across the entire water cycle, promoting healthy ecosystems in urban environments (Stephenson 2013). Blue-Green Infrastructure (BGI): The European Commission defines blue green infrastructure as ‘strategically planned network of natural and semi-natural areas with other environmental features designed and managed to deliver a wide range of ecosystem service’ (Rashetnia et al. 2018) In arid and semi-arid regions, Water Sensitive Urban Design (WSUD) is a cost-effective strategy for managing scarce water resources and offers numerous benefits. Green open spaces are particularly vital in these areas, as they alleviate extreme heat, provide urban cooling, and enhance thermal comfort. These spaces can serve multiple functions, offering not only water management solutions but also ecological, social, and amenity benefits. WSUD practices can also promote stormwater infiltration and groundwater recharge, aiding in drought adaptation. However, several challenges hinder the implementation of WSUD in arid and semi-arid regions. These include health risks associated with water reuse in green areas and on water surfaces, public acceptance issues, and a general lack of experience and knowledge. Additionally, in densely populated areas, the need for extensive spaces to implement water-sensitive solutions presents a significant challenge, and institutional barriers further impede widespread adoption (Elzein et al. 2022). Therefore further research needs to be done on this topic and by introducing more pilot projects. 40 3.7 Planning In Amman: Policies and Stakeholders Since the governorate is administered by GAM and MoLA, several master plans have been developed for its various municipalities. However, these municipalities are not empowered to create their own master plans and lack the necessary staff, equipment, and training and can legally only update existing land use plans. Some of the major master plans are explained below: 1. The Metropolitan Growth Plan: The Metropolitan Growth Plan (MGP), created in 2008 for areas within GAM boundaries, serves as the primary framework to coordinate various sub-plans. It aims to integrate land use, transportation, and infrastructure for compact urban development, promoting public transit and pedestrian travel over cars (GAM 2008). It identifies growth areas, including existing urban spaces and future expansion zones, as well as areas for limited or no growth, such as natural and cultural heritage sites. Though developed before the Syrian refugee influx, the MGP lacks specific provisions for refugees. Only 20 % of the plan has been implemented, prompting ongoing updates by GAM with input from the comprehensive planning department and council, aligning with GAM’s administrative boundaries and directives (UN Habitat 2022). 2. Amman Resilience Strategy City resilience refers to the ability of individuals, communities, institutions, businesses, and systems within a city to endure, adapt, and thrive in the face of various challenges, be they chronic stresses or sudden shocks. Amman has adopted the City Resilience Framework (CRF) developed by Arup and The Rockefeller Foundation, as part of the 100 Resilient Cities initiative. This framework assists cities in evaluating their resilience by identifying strengths, weaknesses, and opportunities. Cities are intricate systems composed of overlapping components, and the CRF serves as a tool to comprehend this complexity and the factors that contribute to resilience. The framework consists of four main dimensions and twelve drivers, offering a comprehensive understanding of what constitutes a resilient city as shown in Figure 14. In 2017, Amman embraced the Amman Resilience Strategy to address urban challenges amplified by refugee influx and climate change. The strategy, built on five pillars—integration, environmental responsibility, innovation, youth empowerment, and unity—proposes an action plan. It aims to align refugee response with the city’s long-term goals, emphasizing job creation and improved access to municipal social services for refugees (GAM and Rockefeller 2017). Figure 14:City Resilience Framework Source: (GAM and Rockefeller 2017) Chapter 3: Amman’s Waterscape: Policies, Challenges, and Global Lessons 41 3. The Amman Green City Action Plan The Amman Green City Action Plan, launched in May 2021, stems from GAM’s efforts to enhance environmental performance and systematically tackle urban environmental issues. It aims to identify, prioritize, and address critical climate change and environmental challenges such as solid waste management, water, wastewater, urban transport, and building energy efficiency. Through extensive stakeholder engagement, the city has devised 37 initiatives slated for implementation by 2025 to meet these objectives (AECOM 2021). Along with many other goals in the area of efficient buildings, transport and waste management, the GCAP has prioritised the role of integrated water resource management. The proposed actions aim to integrate nature-based solutions with traditional infrastructure to effectively mitigate flood risk and improve water quality. Furthermore, they aim to upgrade and expand essential water infrastructure to ensure residents have access to clean water and are connected to wastewater networks. Finally, these actions seek to enhance water resource management by integrating efficient systems into the built environment (AECOM 2021). Among many planned proposals, some of the planned actions are mentioned below: 1. Develop water conveyance and/or storage to reduce flood risk GAM plans to map the flow of water in the city and create a conveyance or storage system to redirect floodwaters from two vulnerable areas in downtown Amman, thus averting potential damage to critical infrastructure. This diversion of floodwaters is expected to yield significant economic savings by minimizing impacts on downtown infrastructure. Additionally, it will alleviate strain on sewerage systems, reducing the risk of wastewater pollution incidents and decreasing the energy needed for water processing within these systems. 2. Integrate WSUD and SuDS It’s crucial to integrate WSUD (water-sensitive urban design) and SuDS (sustainable urban drainage system) principles into land use planning and regulations. These principles enhance the integration of the water cycle into urban design. GAM will incorporate WSUD and SuDS principles into new land-use plans and offer guidance documents on these principles for departments revising relevant regulations and codes (e.g., road maintenance). This approach aims to tackle flooding issues and promote efficient and environmentally-friendly water usage. 3. Pilot SuDs implementation on municipal property The city will integrate Sustainable Drainage Systems (SuDS) principles into all current and future publicly-owned buildings to support the objective of integrating WSUD and SuDS (W4). GAM will pinpoint suiTable sites for pilot SuDS projects within new municipal works and upgrades of existing publicly-owned buildings. With anticipated hydrological changes from climate change, integrating SuDS into city planning will mitigate flood and drought impacts while ensuring a more dependable water supply. The planting aspect of the program will prioritize xeriscaping and drought-resistant vegetation (AECOM 2021). 4. USAID CITIES Programme Outside of GAM, the Ministry of Local Administration (MoLA) supports eight other municipalities. Within the governorate of Amman, the USAID CITIES Programme has financed strategic plans and local development plans for the years 2020-2023 in six municipalities: Al-Ameriyah, Husban, Na’our, Sahab, Muaqqar, and Umm Al-Rasas. These plans were collaboratively developed involving all relevant stakeholders to enhance municipal performance, services, efficiency, and public-private partnerships. However, these plans do not specifically address the needs or integration of refugees into communities. 5. The Amman Climate Action Plan The Amman Climate Action Plan marks the initial step towards a sustainable future, aiming to make Amman carbon neutral while expanding services to meet the city’s growing demands. The plan sets a 40 % reduction target for greenhouse gas emissions by 2030 and fosters collaboration among the government, private sector, development partners, and residents toward a shared vision of carbon neutrality. 6. The Green Growth National Action Plan The Green Growth National Action Plan 2021-2025 lays out pathways for sustainable development that will increase resilience, strengthening Jordan’s capacity to contain shocks and recover from catastrophic events such as COVID-19. The GG-NAP outlines five national green growth objectives on which the Agriculture Sector GG-NAP was developed: 1. Enhance Natural Capital 2. Sustainable Economic Growth 3. Social Development and Poverty Reduction 4. Resource Efficiency 48 Chapter 4: Designing with Nature: Amman’s WSUD Toolkit 49 Chapter 4 Designing with Nature: Amman’s WSUD Toolkit 4.1 Introduction The general idea of this water sensitive urban design toolkit is to put together a set of planning goals and measures that all stakeholders can easily understand. This toolkit not only outlines what these measures do but could also be used as a tool in a more participatory setting. As mentioned in previous sections and also in the case study of the UN Habitat, the inclusion of participants on various levels during the conception and design phase greatly encourage acceptance of shifts and changes in systems. Citizens are more likely to accept the interventions and are more educated about the positive aspects of WSUD. This toolbox includes definitions of the planning goals as guides to selection and design of the measures as well as their significance in the stormwater chain. It deals with the sequence and chain of elements that when put together are highly efficient at managing stormwater in a decentralized manner, by creating a cascading effect as shown in Figure 21. It also aims to emphasize the fact that these measures do not only serve a practical purpose but also enhance the environment with their added benefits. Figure 21: The cascading effect in a stormwater chain in a residential (top) and commercial (bottom) areas. The two diagrams shows how linked sequences of features can capture rainfall and release it back into the landscape. Source: Redrawn and adapted from (Dunnet and Clayden 2007) car park swale permeable paving permeable paving infiltration infiltration infiltration infiltration rain cistern rain cistern stormwater planter stormwater planter pond pond raingarden green roof green roof 50 4.2 Defining the planning goals Planning goals provide a guiding principle to selection of measures and recommendations. They also form the base for the measurement of effectiveness of these measures under different scenarios. Hence, they are stated and defined as follows: 1. Flood reduction: Flash floods are very localised (in space and time), fast-evolving surface water responses to rainfall from intense thunderstorms or a sudden release of water from a reservoir, which results in short lead time and a considerable potential for damage due to high flow velocities and thus high hazard intensities. The goal of reduction of flash flood damage is to direct, capture, or temporarily store large volumes of stormwater as well as reduce the peak runoff rates in order to prevent drastic damage from flooding. 2. Groundwater recharge: Returning the water balance to near natural state is one of the most important goals of this project, and this means facilitating the natural process of water like evaporation and infiltration. Urbanisation has led to an increase in sealed spaces, therefore stormwater is unable to infiltrate into the soil. Since the public supply of drinking water is under a lot of pressure from the growing population and depleted resources, securing the water supply by replenishing the groundwater becomes one of the foremost tasks. 3. Water collection for reuse: While groundwater recharge is one way of contributing to the water supply for consumption, an easier and much more decentralised way to do this would be collection of stormwater for reuse. This can be done by diverting water from sealed surfaces to storage tanks that may be built underground or above. However, this may mean that the water also collects all the pollutants from these surfaces, and may have limited usage. Alternatively, bioretention systems have the ability to cleanse some of the pollutants and can be built with storage tanks as well. In either case, shortening the supply chain makes an important aspect of this research and contributes to mitigating the water scarcity in Amman. 4. Promotion of biodiversity: Replacing paved surfaces, or intensely managed grass areas with mixed native species of plants not only results in overall reduced need for maintenance and inputs of fertilizers, water and energy, but also greatly increases the wildlife and habitat value. The native shrubs and grasses are home to a lot of insects and invertebrates that inhabit the soil, and are the source of nutrition for more visible fauna like butterflies and seed eating birds. Co existing with the variety of flora and fauna increases the appeal of any urban space and hence makes for a good planning goal. 5. Quality of Stay: As mentioned in the previous points, when planned strategically, blue green measures automatically add to the aesthetic appeal of any place. Additionally, making a space beautiful also enhances its value to live and work in. While in urban environments, water is often seen as a nuisance, something to get rid of, or controlled and contained, if managed through aesthetic infrastructure, the presence of the same water enriches the experience of the city. 6. Balanced Urban Climate: At the basic level, substituting hard paced surfaces with vegetation cools the summer landscape. Hard surfaces store heat from the sun and re radiate it during the night, warming the adjacent air while reflection the same heat during the day. On the other hand, plants provide shade but also cool the air through evapotranspiration. With increased paved areas in the city causing the urban heat island effect, a goal for future development should focus on balancing that urban climate through the introduction of more green spaces. 7. Environmental Education: Lastly, improving public knowledge on environmental issues should be a priority since it affects their lifestyle. The design of urban spaces has the ability to influence and shape human behaviour. Having an unlimited supply of water through a tap for example, makes a person completely unaware of the source ot comes from and the processes it goes through to be consumed by the user. When the same processes are made visible through measures implemented in the surroundings, streets, parks and backyards, a person is likely to be more conscious of their consumption patterns. It also raises the likelihood of people participating in the design and implementation processes of these measures throughout their neighbourhood. 4.3 Measures and their descriptions The selected measures are detailed in this section as a set of info cards, that may be distributed at a stakeholder workshop or just to inform the reader of this research about the details of the measure. Therefore, it includes a representative icon, an indication of costs, a description, criteria to implement it, maintenance required and how it ranks for the various planning goals mentioned before. The ranking is about how well a measure may perform for each planning goal based on the expert discussions at HW, 2024. Lastly, it also included a graphic representation of how these measure work and/or an example. Chapter 4: Designing with Nature: Amman’s WSUD Toolkit 51 Green roofs DESCRIPTION Green roofs are vegetated areas installed on building rooftops for various purposes, including visual appeal, ecological benefits, improved building performance, and reduced surface water runoff (CIRIA 2015). They can be of two types: • Extensive: low substrate depth, low load on buildings, inaccessible, simple planting • Intensive: deeper substrate depth, higher loads, accessible as the variety of plants need more maintenance. • Can be applied to public or private building roofs • Accessibility requirements • Imposed loads when saturated, including maintenance loadings • The need for integration of rooftop equipment, such as vents, air-conditioning systems, solar panels and/or RWH systems • Management of drainage - outflow to a storage tank, integrated into landscape, connection to the drainage system, etc. • Suitability of plants • Filtration • Evapo-transpiration • Purification • Retention • Biological absorption • Micro climate improvement $$ Flood Reduction Water collection for reuse Groundwater Recharge Biodiversity Urban Climate Quality of Stay Environmental Education PLANNING GOALS PROCESSES MAINTENANCE DESIGN CONSIDERATIONS Figure 22: The green roof will absorb and gradually release rainfall - unlike a conventional roof, which rapidly sheds the water into connecting drains. Source: Redrawn and adapted from (Dunnet and Clayden 2007) Figure 23: Section of a typical green roof buildup Source: Redrawn and adapted from (Dunnet and Clayden 2007) growing medium filter mat drainage layer root barrier waterproof layer roof Intensive roofs need more frequent maintenance like mowing of grass and de-weeding, whereas extensive roofs only need bi annual checks for unwanted plants and cleaning. 52 Swales/ Bioswales DESCRIPTION Swales are linear depressions covered with grass or more dense vegetation designed to convey, treat and often attenuate surface runoff (CIRIA 2015; DWA 2006). Runoff is collected temporarily on the surface and then filters through the vegetation and underlying soils. Bioswales may involve a continuous component of bioretention along the length of the swale, or a portion of bioretention before the outlet of the swale. For heavier rainfall events, water will flow along the swale though the velocity is controlled by vegetation and simultaneous infiltration (CIRIA 2015). • Litter and debris removal • Mowing of the grass and maintenance of the vegetation, maintaining the height to at least 75-150mm. • Occasional sediment removal. • Infiltration • Filtration • Evapo-transpiration • Purification • Retention • Biological absorption • Micro climate improvement • Conveyance $ Flood Reduction Water collection for reuse Groundwater Recharge Biodiversity Urban Climate Quality of Stay Environmental Education PLANNING GOALS PROCESSES MAINTENANCE DESIGN CONSIDERATIONS • Parabolic or trapezoidal cross section, with the base between 0.5-2m. • The side slopes should be between 25 % to 33 %, to improve pre-filtration of the runoff where space permits. • When applied along streets, the minimum length should be 5 m for maintenance access and with depths between 400600 mm and a ponding depth of 300mm. • The flow velocity and vegetation should be designed so that when water flows along the bioretention swale the filter material is not eroded. • To achieve effective biofiltration, the base of the swale must be constructed as a series of flat areas that are terraced down the length of the swale. • SuiTable vegetation should be chosen that can withstand inundation and flow of water. • An underdrain may be added to provide additional treatment and conveyance capacity beneath the base of the swale and prevent waterlogging. Figure 24: (Above) Section of a typical swale with overflow into the drainage system Figure 25: (Right) A vegetated swale with geo-textile to permeate as well as convey stormwater runoff Source: Redrawn and adapted from (Dunnet and Clayden 2007) Chapter 4: Designing with Nature: Amman’s WSUD Toolkit 53 Raingardens DESCRIPTION Bioretention systems like raingardens are shallow landscaped depressions and are a cost effective retrofit since they are flexible in terms of shape, materials, plantings and dimensions. They can reduce runoff rates and volumes by improved infiltration through engineered soils and vegetation. The runoff is either collected using an underdrain or is fully or partially infiltrated to the surrounding soils and is further reduced by evapotranspiration and plant transpiration (CIRIA 2015). • Litter and debris removal • Regular removal of weeds • Cleaning access to underdrains where necessary • Infiltration • Filtration • Evapo-transpiration • Purification • Biological absorption • Micro climate improvement $ Flood Reduction Water collection for reuse Groundwater Recharge Biodiversity Urban Climate Quality of Stay Environmental Education PLANNING GOALS PROCESSES MAINTENANCE DESIGN CONSIDERATIONS • Can be implemented in most types of developments, along roads, parking spaces, roundabouts, already landscaped lawns, in public or private areas • Can be creatively shaped according to requirements • Depths between 150-300mm, can be deeper depending on site conditions • Filter medium depth 400-1000mm • Overflow through surface drain or underdrain system • SuiTable perennial vegetation that promotes biodiversity Figure 26: How a raingarden works Source: (Berkshire Environmental Action Team 2021) 54 Stormwater Planters DESCRIPTION These are boxed systems, which can be prefabricated, built above the ground surface with a planted soil mix and an underdrain to collect filtered water. They are commonly used to manage runoff from nearby roofs and are particularly useful for retrofitting in urban areas. They may be built to infiltrate directly in the soil below or can be further connected to the next step in the drainage chain (CIRIA 2015) (Dunnet and Clayden 2007). • Litter and debris removal • Weed removal to avoid clogging • Occasional sediment removal. • Infiltration • Filtration • Evapo-transpiration • Biological absorption • Micro climate improvement • Conveyance $ Flood Reduction Water collection for reuse Groundwater Recharge Biodiversity Urban Climate Quality of Stay Environmental Education PLANNING GOALS PROCESSES MAINTENANCE DESIGN CONSIDERATIONS • Minimum depth of 300mm • Waterproofing when constructed right next to a building • SuiTable vegetation to promote biodiversity • Addition of stones or pebbles to moderate the velocity of water from the downspout • Outflow into a drain or next step in the drainage chain • Can be integrated creatively into the urban landscape where space is limited. Figure 27: A series of stormwater planters collecting water between two structures integrated into the landscape, creating a drainage chain to reduce runoff volumes and rates, Source: (Central Steel Service Inc 2019) Chapter 4: Designing with Nature: Amman’s WSUD Toolkit 55 Rainwater Harvesting DESCRIPTION Rainwater harvesting is the collection of runoff from roofs and other impermeable surfaces which can be stored, treated if required and reused for many purposes (CIRIA 2015). Rooftop rainwater harvesting typically requires the construction of a storage tank, either on the surface or underground. The collected water can be used for irrigation, or for non-poTable domestic purposes on site, or can be directed to a treatment plant. The storage tanks can be designed and located to serve individual buildings like residences or can be larger and collect runoff from several buildings. • Inspection of tanks for debris and cleaning annually • Storage • Reuse $-$$ Flood Reduction Water collection for reuse Groundwater Recharge Biodiversity Urban Climate Quality of Stay Environmental Education PLANNING GOALS PROCESSES MAINTENANCE DESIGN CONSIDERATIONS • Disconnection of the downspout from roofs from the drainage network and into a storage tank. • The size of the storage tanks depends on the amount of rainfall collected form the rooftop, the space available for the tank and the purpose for which the water will be reused. • Accordingly, a pump may need to be installed to extract the stored water. • An overflow outlet needs to be installed that could connect to the system drainage. Figure 28: Section of RWH system Source: (Civil Engineer DK 2021) Figure 29: RWH in a garden for irrigation Source:(UltraTech Cement 2021) 56 Permeable Pavements DESCRIPTION Pervious pavements support pedestrian and vehicular traffic while allowing rainwater to infiltrate through the surface into the underlying structural layers. The water is temporarily stored beneath the surface before being used, infiltrating into the ground, or being discharged in a controlled manner downstream (CIRIA 2015). They can be made either of porous materials like porous asphalt or concrete in which case water can infiltrate throughout the surface of the material. Or they are commonly blocks of impermeable materials with wide joints filled with grit through which water seeps in. • Inspection and repair paving as required • Regular checks for silt clogging the joints • Infiltration • Evapo-transpiration • Micro climate improvement $$ Flood Reduction Water collection for reuse Groundwater Recharge Biodiversity Urban Climate Quality of Stay Environmental Education PLANNING GOALS PROCESSES MAINTENANCE DESIGN CONSIDERATIONS pavers - gaps filled with gravel or sand sand open graded base material geotextile fabric sub base • As they are an alternative to impermeable areas, they require no extra space to install. • The choice of materials whether it is porous asphalt, paver blocks or reinforced grass depends on the traffic loads and visual appearance required. • The aggregate sub base might be replaced by geo-cellular sub base to improve infiltration and can also aid in storage of the runoff. • When an adjacent impermeable area or roofs are draining onto the pervious pavement, the recommended ratio impermeable/pervious surface is up to 2:1 (CIRIA, 2015). Figure 30: Typical section of a permeable pavement Source: Redrawn and adapted from (Dunnet and Clayden 2007) Figure 31: Example of a permeable pavement in a parking lot Source: (Hardcastle 2022) Chapter 4: Designing with Nature: Amman’s WSUD Toolkit 57 New Green Spaces DESCRIPTION Replacing paved surfaces or intensely managed grass areas with mixed, naturalistic and diverse native vegetation is the objective of this measure. Paved areas contribute highly to urban heat island effect and increase runoff rates and volumes. On the other hand, intensely managed landscapes with monoculture vegetation is not effective in soaking up or trapping excess runoff, and are not effective in removal of contaminant as well. These diverse green spaces whether in small pocket gardens or larger parks and gardens not only reduce needs for maintenance, but also greatly increase the wildlife and habitat value and improves the overall quality of stay (Dunnet and Clayden 2007). • Removal of weeds • Regular removal of litter and debris. • Infiltration • Filtration • Evapo-transpiration • Biological absorption • Micro climate improvement • Retention $-$$ Flood Reduction Water collection for reuse Groundwater Recharge Biodiversity Urban Climate Quality of Stay Environmental Education PLANNING GOALS PROCESSES MAINTENANCE DESIGN CONSIDERATIONS • Disconnection of the downspout from roofs from the drainVery flexible in terms of size, scale, typology and can be implemented in dense urban areas on private or public property. • The most effective biodiverse landscapes are a combination of grasslands, wetlands, woodlands and scrub. The combination of these promotes biodiversity and creates an “ecotone” – two or more types of vegetated areas that interact with each other and are often dependent. • They can be combined with play areas for children and pedestrian paths for wandering. • They can incorporate a wide variety of WSUD measures like wetlands, retention areas and swales, incorporating water into the landscape for visual quality and stormwater management (Dunnet and Clayden 2007). Figure 32: Spring in the Highline in New York. A corridor of biodiversity in a dense urban setting brings life to this post industrial district. Source: (Sangaku San 2015) 64 A Figure -ground diagram employs a mapping method to depict the distinction between built and unbuilt spaces within urban settings as shown in Figure 40. It portrays the areas occupied by buildings as solid forms (Figure ) and the communal areas such as streets, parks, and plazas as empty spaces (ground). According to Morphocode (n.d.), this map is used to explore built form patterns and the continuity and relation of open space. This map does not include construction sites as built areas. As per area calculations, as shown graphically in Figure 41, the area of the catchment is 1317ha while the built up area is 151ha, which is only 11.48 % of the total catchment area. As shown in the map, the lower part of the catchment is densely built with very less open space, while the upper catchment is yet to be developed. Figure 40: Figure Ground Map of the catchment Source: Author, based on HW, 2024 5.1.1 Figure Ground Map Figure 41: Graph showing the built and unbuilt areas in percentage of the total catchment area. Source: Author, based on HW, 2024 11.5 % Built-up Legend Built up Area Unbuilt Area Site Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 65 The built up area is further classified in this map (Figure 42) based on their function. As shown in the map and in Figure 43, the area is dominated by residential buildings, with relatively few commercial buildings, and only 4 schools and adjoining religious buildings making up less than 2 % of public areas. In this classification, certain buildings had no information about their function and have been classified under “others”. There are a few mutlifunctional buildings in the area, which are generally offices or commercial spaces shared with residences above them. From this map, we can gather that most of the built area may not be used for measures, however, a scenario has been designed to include residential buildings as well and their effect on managing the stormwater of a subcatchment. Figure 42: Building classification based on function Source: Author, based on HW, 2024 5.1.2 Building Classification Map Figure 43: Graph showing the share of different building classifications. Source: Author, based on HW, 2024 Legend Residential Commercial Public Buildings Multifunctional Others Streets Site 85.48 % 10.70 % 1.34 % 1.12 % 1.36 % Residential 85.48 % Commercial 10.70 % 66 Furthermore, the residential buildings are further classified based on data from HW(2024) into different categories based on planning regulations. This shows the potential to use the open spaces surrounding different residences to minimize the outflow of stormwater from their properties. Through this map (Figure 44), residences with more open space may be regulated for the same, while those with lesser open spaces may be compensated by other measures like underground storage tanks or limited outflow of stormwater. Figure 45 is a graphical representation of the share of different residential classes. A detailed description of the different building regulations for the basic 4 types of residential plots is described in Appendix D. Figure 44: Classification of residential buildings based on typology Source: Author, based on HW, 2024 5.1.3 Residential Classification Map Figure 45: Graph showing the share of different residential classes. Source: Author, based on HW, 2024 Type A 39 % Type B 39 % Type C 18 % Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 67 Type A 39 % The Land Use Map in Figure 46 depicts the Planned or Future land use designations that provide general guidance in the density, character and location of land uses and serves as a baseline for analysis. Here, the land use has been categorized into residential, commercial, institutional, multifunctional, religious,and public areas; and spaces that have no assigned function as of now are categorized as “others”. This is done based on data from HW (2024), and open spaces assigned by landuse as well as those in schools and religious places are assumed as public space. It is observed in Figure 47 that this public space is less than 3 % of the entire catchment, while residential space is the highest, followed by multifunctional spaces. Most of the assigned multifunctional space is undeveloped at the moment but could have potential for implementing WSUD measures. Figure 46: Landuse classification based on function Source: Author, based on HW, 2024 5.1.4 Landuse Map Figure 47: Graph showing the share of Landuse based on function. Source: Author, based on HW, 2024 Legend Streets Residential Commercial Institutional Multifunctional Public Areas Others Streets Site 80.64 % 4.62 % 1.03 % 10.87 % 0.46 % 2.28 % Commercial 4.62 %Commercial 4.62 Multifunctional 10.87 % Residential 80.64 % 68 In this map, (Figure 48) the landuse is further categorized into developed or undeveloped areas. Here, construction sites are also considered under developed areas as for the purpose of this analysis, it shows an increase in the sealed areas. It is interesting to observe in the following maps that even though nearly half of the catchment is still undeveloped (see Figure 49), it contributes to the stormwater volumes accumulated at the end of the catchment. This further supports the argument that an increase in sealed areas will lead to an increase in the runoff volumes. Figure 48: Classification of developed and undeveloped areas. Source: Author, based on HW, 2024 5.1.5 Development Map Figure 49: Graph showing the share of developed and undeveloped areas. Source: Author, based on HW, 2024 Legend Developed Undeveloped Site 45.50 % 55.50 % Undeveloped 55.50 % Developed 45.50 % Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 69 This map is classified on the basis of ownership of the land and is divided into public, private and mixed. The largest share of land is privately owned as most of it is residences or commercial spaces. Public land is merely spaces like schools and mosques and some open areas surrounding them. The mixed ownership is of multifunctional spaces as they are assumed to also have some public space along with private spaces. A summary of the shares of landuse ownership is shown in Figure 51 and is geospatially illustrated in Figure 50. Figure 50: Classification of land based on ownership. Source: Author, based on HW, 2024 5.1.6 Public-Private classification Map Figure 51: Graph showing the share of Landuse based on ownership. Source: Author, based on HW, 2024 Legend Public Private Mixed Others Site 1.82 % 85.48 % 10.88 % 1.82 % Private 85.48 % Mixed 10.88 % Public 1.82 % Others 1.82 % 70 This map classifies all the available open space in the catchment based on their typologies as shown in Figure 52 and their share in Figure 53. It is interesting to note that most of the undeveloped space is referred to as “infill” instead of just being labeled undeveloped. Infill development refers to the practice of making improvements within existing urban areas, typically on underused or vacant land. This approach is designed to curb urban sprawl by optimizing the use of existing infrastructure and promoting denser, more walkable communities. Such developments can range from residential homes to businesses and public spaces, aiming to enhance neighborhoods and reduce environmental impacts by avoiding the need for new infrastructure (Urban Design Lab, 2023). Therefore, this shows the potential areas that may be repurposed for the inclusion of WSUD strategies. Figure 52: Classification of open spaces based on typology Source: Author, based on HW, 2024 5.1.7 Open Space Classification Map Figure 53: Graph showing the share of open space typologies. Source: Author, based on HW, 2024 Legend Private open space Public open space Infill Multifunctional Public gardens Others Site 32.43 % 1.54 % 50.81 % 12.76 % 0.16 % 2.31 % Infill 50.81 % Private open space 32.43 % Multifunctional 12.76 % Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 71 The map in Figure 54 depicts the rainfall data of the 2019 flood event as per HW, 2024. It shows the sinks in the topography and where the water gets collected the most. It can be observed from this map that most of the water flows along streets naturally as they are lower than the built up areas. The runoff flows along the highway towards the north east where lies the lowest outlet of the catchment. It may also be observed that some of the residential areas are highly affected due to the large volumes of water being collected there. Figure 54: Hydraulic map showing sinks and flow paths Source: Author, based on HW, 2024 Legend 0.004 - 0.005 0.005 - 0.007 0.007 - 0.029 > 0.029 Site 5.1.8 Hydraulic Map 72 Figure 55: Identification of hotspots Source: Author, based on HW, 2024 Legend Hotspots Selected Hotspots 0.004 - 0.005 0.005 - 0.007 0.007 - 0.029 > 0.029 Buildings Site 1 2 3 4 5 6 7 8 9 10 11 12 Identification of hotspots has been illustrated in the Figure 55, by overlaying the landuse or satellite image and hydraulic maps, pointing out areas that are at a risk of flooding. This also includes the undeveloped areas. To better understand this, each of the hotspots has been ranked for their level of risk and potential for implementation of WSUD measures as low, medium and high. For example, public spaces and open spaces have high potential for implementation of wsud, and low lying areas and sinks in the hydraulic maps show spots of high risk. The hotspots and their rankings have been described in Table 5. A matrix of these hotspots is depicted in Figure 56, according to their level of risk and potential. Further, their typologies have been identified and 3 hotspots have been chosen, from each of the typologies. These are, as per the numbers designated: 1. Hotspot 7: The high density residential quarter with high risk and low potential due to lack of public space except for streets, as given the land use, most of the catchment will be developed on the same pattern. This is Hotspot C 2. Hotspot 8+9: The mixed use development of the Royal village project has been combined and analysed as a single hotspot (Hotspot B) as it is at high risk and has high potential of implementing WSUD before construction 3. Hotspot 10: This is a quarter with a school, a mosque and apartment buildings and has a high potential given the availability of open space in the school and public gardens, hence represents public areas, Hotspot A. An in-depth analysis of these hotspots has been carried out in the next section. 5.1.9 Identification of Hotspots Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 73 Figure 56: The Risk - Potential matrix for all the hotspots Source: Author Table 5: Description of the hotspots. The selected hotspots for further analysis have been highlighted. Source: Author 1 2 34 5 6 789 10 11 12 Risk Potential Low Low Medium Medium High High Hotspot Number Typology Description Risk Potential 1 Streets Highway and surrounding areas towards the north of the catchment Medium High 2 Residential Developing residential neighbourhood with no public space Medium Medium 3 Streets Intersection of 2 major roads and surrounding residential area High Medium 4 Residential Existing semi developed residential area with no public open space High Medium 5 Residential Existing semi developed residential area and street intersections High High 6 Residential Medium density residential area with no public space High Medium 7 Residential High density residential quarter with no public open space High Low 8 Mixed Use North-east part of the Royal Village project (Offices as per proposal) High High 9 Residential South-west part of the Royal Village Project (Residential as per proposal) High High 10 Public area/ Mixed use School, mosque and residential buildings, with unused open space and public gardens Medium High 11 Public area School and surrounding residential area with some open space in the school grounds Low Medium 12 Public area School and surrounding residential and commercial area with limited open space Low Low 80 Scenario 1 Type of surface Ac,i Ψm,i Aimp Ap m² m² m² Building rooftops 10628.52 0.90 9565.66 Streets 3857.15 0.90 3471.44 Paved 15427.58 0.75 11570.69 Existing Green 744.78 0.20 148.96 Public Gardens 3513.40 0.10 351.34 Private Gardens 7871.84 0.30 2361.55 Undeveloped Open Space 5689.46 0.40 2275.78 Total 47732.72 24607.79 5137.63 Scenario 2 Type of surface Ac,i Ψm,i Aimp Ap m² m² m² Building rooftops 5109.93 0.90 4598.94 Streets 1352.90 0.90 1217.61 Paved 6033.76 0.75 4525.32 Existing Green 780.45 0.20 156.09 Public Gardens 6419.96 0.10 642.00 Private Gardens 7420.76 0.30 2226.23 Undeveloped Open Space 0.40 0.00 New Green 7677.53 0.10 767.75 Green Roofs 5506.24 0.40 2202.50 Bioswale 928.34 0.20 185.67 Permeable Pavement 5485.27 0.30 1645.58 Raingarden 378.18 0.10 37.82 Total 47093.33 10341.87 7863.63 Scenario 3 Type of surface Ac,i Ψm,i Aimp Ap m² m² m² Building rooftops 0.00 0.90 0.00 Streets 1352.90 0.90 1217.61 Paved 6033.76 0.75 4525.32 Existing Green 780.45 0.20 156.09 Public Gardens 6419.96 0.10 642.00 Private Gardens 7420.76 0.30 2226.23 Undeveloped Open Space 0.40 0.00 New Green 7677.53 0.10 767.75 Green Roofs 5506.24 0.40 2202.50 Bioswale 928.34 0.20 185.67 Permeable Pavement 5485.27 0.30 1645.58 Raingarden 378.18 0.10 37.82 Total 41983.40 5742.93 7863.63 Table 8: Calculation of reduced areas for Scenario 1 Source: Author Table 9: Calculation of reduced areas for Scenario 2 Source: Author Table 10: Calculation of reduced areas for Scenario 3 Source: Author Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 81 Table 11: Runoff volumes for the three scenarios Source: Author Figure 61: Runoff volumes for the three scenarios Source: Author In the next step, the runoff volumes are calculated as per equations 3, 4 and 5 in section 2.5 for the three scenarios and the results are described in Table 11. It is observed that for scenario 1, that is the current status quo, a maximum runoff volume of 1528 m³ is collected after 12 hours of rainfall. On the other hand, by implementing measures in public areas in scenario 2, the peak runoff volume is reduced to 404 m³ and after around 9 hours, all the water is managed on site. This is reduced further in scenario 3, where the maximum runoff is 216 m³ after 2 hours of rainfall and is completely managed on site after 3 hours. The comparison can be seen graphically in Figure 61. Duration Rainfall intensity Volume S1 Volume S2 Volume S3 min l/s ha m³ m³ m³ 5 169.02 172 97 69 10 123.15 245 133 92 15 107.86 319 170 116 30 83.4 480 243 160 60 63.11 700 326 201 120 47.26 993 404 216 180 38.64 1157 402 172 360 27.69 1469 287 -43 720 18.54 1528 -288.26 -730 1440 10.29 509 -2135 -2625 0 200 400 600 800 1000 1200 1400 1600 1800 0200 400 600 800 1000 1200 1400 1600 Scenario 1 Scenario 2 Scenario 3 Duration in minutes Volume in m3 82 Further, a calculation of the peak runoff rates is also done following the described method in section 2.5. The peak flow describes the maximum discharge during the period of runoff caused by a storm over an area (Sen 2015). In order to calculate it for the three scenarios as per equation 6, the areas of different sealed and unsealed surfaces are taken, multiplied by their respective runoff coefficients as in Tables 8 and 9, and then cumulated to form area (A). This value is then multiplied by the different rainfall intensities in mm/hr for different times of concentration as in equation 8. The values are shown in Table 12 and are graphically depicted in Figure 62. The calculations show that the discharge rate peaks in the first 5 minutes of rainfall and is the highest in scenario 1 which has the highest percentage of sealed surfaces. Lowering the sealed surfaces in scenario 2 and 3 by introducing WSUD measures lowers the peak runoff rates as well. While a major difference can be seen between Scenario 1 and 2, disconnecting the building rooftops in scenario 3 does not create a major difference in comparison to scenario 2. Scenario 1 Scenario 2 Scenario 3 Area (A) 29745.42 18205.50 13606.56 Duration Rainfall Intensity Runoff Rate (Q) min mm/h l/s 5 60.80 502.77 307.72 229.98 10 44.30 366.33 224.21 167.57 15 38.80 320.85 196.37 146.77 30 30.00 248.08 151.83 113.48 60 22.70 187.71 114.89 85.87 120 17.00 140.58 86.04 64.30 180 13.90 114.94 70.35 52.58 360 9.96 82.36 50.41 37.67 720 6.67 55.16 33.76 25.23 1440 3.70 30.60 18.73 14.00 0.00 100.00 200.00 300.00 400.00 500.00 600.00 0200 400 600 800 1000 1200 1400 1600 S1 S2 S3 Table 12: Runoff rates for the three scenarios Source: Author Figure 62: Runoff rates for the three scenarios Source: Author Duration in minutes Runoff rates in l/s Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 83 5.2.1.5 Further design recommendations To accurately calculate the water holding capacity of the measures mentioned before, several factors need to be considered. 1. Soil Type and Porosity: Different soil types have varying water retention capacities. Sandy soils drain quickly, while clay soils retain more water. As mentioned before and used in the calculations, this area has sandy loamy soil with a good infiltration capacity. 2. Depth of the measure: The depth of the measure such as a rain garden or swale determines how much water it can store. For example with a depth of 0.3m, that’s the maximum amount of water it can hold vertically. 3. Vegetation and Mulch: Plants and mulch within the rain garden can affect its water holding capacity by absorbing and slowing down the movement of water. This factor needs to be considered based on the types of plants and amount of mulch present. 4. Slope and Drainage: The slope of the land and drainage patterns surrounding the measure can affect how much water it receives and retains during rainfall events. To estimate the volumes of stormwater that can be collected in the measures designed for this project, only the dimensions of the measures are considered, that is, the area calculated before multiplied by the design depth. For more accurate volumes, the conceptual designs can be detailed further and simulated in softwares such as STORM or SWMM. 1. Green roofs: Green roofs are considered to be semi intensive to intensive so an average depth of substrate varies between 0.15 - 0.6m and is assumed to be 0.5 for this scenario. Further depending on different types of substrates a green roof can hold between 30 % - 60 % of its volume in water. Here it is assumed that it can hold 50 % of its volume. Therefore, with an area of 5506.24 m² and a depth of 0.5m, the actual volume of the green roofs would be 2,753.12 m³. But since its capacity is only 50 %, the volume of water it can actually hold is 1,376.56 m³. 2. Bioswales: Bioswales are introduced in this hotspot to convey the runoff from the surrounding streets, especially the one to the south of the hotspot that is vulnerable to flooding, towards the open space of the school. With an area of 928.33 m² and depth of 0.3m, it has the capacity to hold 278.5 m³ of runoff. Bioswales have also the capacity of increased infiltration, therefore slowing down the discharge rates as well as the runoff volumes. However this factor is not taken into account here while calculating the volume. 3. Raingardens: Raingardens are shallow landscaped depressions that not only reduce the runoff rates and volumes but also treat for water quality through engineered soils and plantation. Therefore, with an area of 378.182m² and a depth of 0.3m, the capacity of the raingardens depicted in Figure 58 is 113.45 m³. 4. Rooftop RWH: Rooftop rainwater harvesting is the measure assumed for the third scenario, where the runoff from the roofs is assumed to be managed within the private plots, utilising the open space. In this scenario, the disconnection of rooftop reduces the runoff volume from 404 m³ to 216m³. Which means that tanks of the capacity 118 m³ needs to be installed in the private properties. This can be done simply by diverting the drain outlet from the roof into a tank for collection and reuse within the household. However, this water may also be diverted into a raingarden within the open space of a private property, through swales, hence slowing down the runoff, and creating an aesthetic flow and use of the stormwater as depicted in Figure s 85 and 86 in section 5.2.3.5. The excess or overflow from the raingarden may then still be collected in an underground tank, but it would go through layers of infiltration, hence yielding a better quality of water stored. In this hotspot, the private buildings are multistoreyed apartment buildings, that have common access to public parks. Therefore, instead of merely installing tanks, this rooftop runoff can be used in more dynamic ways and can be creatively integrated in to the landscape as shown in Figure 63. This Figure depicts a case example of 10th@Hoyt Apartments complex in Portland, Oregon where a system of concrete channels and cascades routes the water from the roof into the courtyard, where it visibly flows over back lit and coloured glass dotted Cor-Ten steel weirs into rectangular river stone filled detention basins and a cistern. 84 Figure 63: 10@Hoyt Apartments is focused on the activation of water in the landscape. Water flows through Cor-Ten steel channels from the rooftops into detention beds filled with river stones. The area, though not entirely unsealed, has green elements combined with open seating and integrates stormwater into the landscape in an artistic manner. Source: (Koch Landscape Architecture 2019; Paragon Corporate Housing 2023) Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 85 The Table 14 shows a comparison of the runoff volumes for heavier rainfall scenarios, with a return period of 25 years and 100 years, for all 3 design scenarios to get an idea of whether the conceptual measures would have the capacity to attenuate these volumes. The total attenuation capacity for the measures in scenario 2 is 1769 m³ which hugely surpasses the requirements even in a 100 year rainfall event (1132 m³) as shown in Table 13. This indicates that the measures recommended can be decreased. For example, the green roofs on the school and mosque buildings need not be implemented on 100 % of the roof area for stormwater management purposes. Even if it was to be decreased by 50 %, the runoff can be managed on site with other measures. Additionally, the integration of rooftop RWH decreases the system runoff volume by attenuating a volume of 118 m³, which might be even reused as per the feasibility on site. For a 5 year rainfall event, after scenario 3, only a volume of 216 m³ needs to be attenuated which can easily be done with the help of bioswales alone, that have the capacity of 278 m³. These decisions of which measures to keep and what can be reduced and how should be taken after an active stakeholder meeting and further detailed assessment of the site and detailed stormwater simulations. Type of surface Ac,i Depths Calculated Volume Volume capacity Actual Volume m² m m³ m³ Permeable Pavement 5485.27 0.00 0.00 New Green 7677.53 Green Roofs 5506.24 0.50 2753.12 0.50 1376.56 Bioswale 928.34 0.30 278.50 278.50 Raingarden 378.18 0.30 113.45 113.45 Total volume attenuated in scenario 2 3145 1769 Rooftop RWH 118 118.00 Total volume attenuated in scenario 3 3263 1887 Runoff Volumes Duration Scenario 1 Scenario 2 Scenario 3 5 years 25 years 100 years 5 years 25 years 100 years 5 years 25 years 100 years min m³ m³ m³ m³ m³ m³ m³ m³ m³ 5 172 239 288 97 138 168 69 99 122 10 245 342 415 133 193 237 92 137 170 15 319 446 541 170 248 306 116 174 218 30 480 680 827 243 365 455 160 252 319 60 700 1000 1221 326 510 646 201 338 440 120 993 1443 1771 404 679 880 216 422 572 180 1157 1703 2110 402 737 986 172 422 608 360 1469 2249 2849 287 765 1132 -43 314 589 720 1528 2586 3384 -288 360 848 -730 -246 119 1440 509 1683 2558 -2135 -1416 -881 -2625 -2088 -1688 Table 13: Summary of the attenuation cpapcity of recommended measures Source: Author Table 14: Comparison of runoff volumes for the three scenarios for return periods of 5, 25 and 100 years. ource: Author 86 Hotspots Areas S1 Private gardens Public Gardens Streets Undeveloped open space Hotspot buildings Residential Buildings Streets 5.2.2 Hotspot B: Royal Village Project 5.2.2.1 Description The Royal Village Project is situated in a strategic area in Amman on the road leading to the Dead Sea and provides an excellent area to analyse as it is currently not developed but has a proposed masterplan. This allowed the creation of an additional scenario of pre-development or “greenfield” scenario as shown in Figure 64, where the runoffs volumes and discharge rates can be compared with the proposed masterplan and with the results, further integration of WSUD measures can be recommended and even implemented easily. However, the proposed masterplan of the area describes a mixed-use development as shown in Figure 65. As per the architects and planners of the project Alnasser and partners (2024), the location allows for a main pathway connecting a new retail center to a major hospital, lined with commercial outlets to attract residents and visitors. The remaining areas are residential, each with a distinct character: apartments near the main road with central parks, and villas on higher ground offering city views, including both single and semi-detached options to suit different family needs. As observed from the overlay of the hydraulic map in Figure 64, it can be observed that the residential area in the south and the offices in the north are at high risk of flooding. Also, the majority of public space is paved and only a small percentage of green area is accessible to the public. A detailed analysis of the areas is done in further sections. 5.2.2.2 Identification of types of surfaces and areas As per the pre-development state or in Scenario 1A, the site lies in the southern half of the catchment and is surrounded by residential areas. It is prone to flooding in the north east and south west parts as shown in Figure 64. For the sake of simplified calculation, the runoff coefficient of this area is taken to be 0.4 and a small construction as observed by satellite imagery is included as a building, as described in Table B1 in Appendix B. On the other hand, as per scenario 1B, or the proposed masterplan, 50 % of the area gets paved by streets and pavements. Further only a mere 22 % of the site remains unsealed with a major portion being private property. A detailed description with areas is shown in Table B2 in appendix B. Figure 64: The royal village project in its current “greenfield” state, overlayedby a layer of hydraulics showing sinks within the hotspot Source: Author, based on GIS analysis Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 87 Figure 65: The royal village project masterplan as proposed by the architects Alnasser + Partners Source: Alnasser + Partners, 2024 88 5.2.2.3 Conceptual design of WSUD measures for Scenarios 2 and 3 For the scenario 2, as before, measures have been conceptualised only for the public spaces as shown in Figure 68. Taking the masterplan as the base, an attempt is made to unseal most paved areas. Permeable pavements have been implemented in all parking lots. All public buildings including the offices, commercial spaces and hospital have a semi-intensive green roof. The streets that are 15m wide in the commercial areas and 12m wide in the residential areas could include swales that convey the stormwater runoff and slow down the discharge rates. These street sections are described in Figure s 66 and 67, integrating landscape elements and showing the basic profile of the streets. Additionally, the most potential was observed in the paved area between the commercial space that is a plaza according to the masterplan. This could be converted into a “green corridor”, a multifunctional open space that connects the various buildings around but also provides a space for potentially treating and retaining stormwater in this hotspot. Depending on the feasibility of the site conditions, some areas might have public furniture, playgrounds, open gyms or merely green spaces, with differences in levels to accommodate the retention of stormwater. This could also integrate the public park that is included in the masterplan through creative landscape design. The water from the swales could be conveyed towards this green corridor, hence reducing the risk from the residential areas. This would greatly improve the aesthetics and biodiversity in the area, hence adding value and promoting awareness of urban waters. Alternatively, as per the feasibility, since the infiltration potential of the site is observed to be low (HW, 2024), this plaza could be designed for detention. That is, by lowering the level of the plaza or by creating a multifunctional space that could also hold water and slowly discharge it as shown in Figure 19 and as discussed in the case study of Rotterdam in section 3.8. While the percentage of sealed or unsealed area may be determined on a closer inspection of site conditions, cost benefits and other factors, a combination of all these elements can be designed in detail in further approaches. A summary of the changes made in permeable and impermeable areas is shown in Table B3 in appendix B. Figure 66: Street E section of a 15m wide road with a bioretention area acting as a buffer between the main street and the Royal village project residential area Source: Author 2m 2m Pedestrian PedestrianBioretention Swale Traffic zone Traffic zone 4m 4m 3m Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 89 Figure 67: Street F section of a typical 12m wide road with a bioretention area acting as a median between two lanes of traffic. Source: Author In scenario 3, the rooftops of the private buildings are disconnected from the system with the assumption that the runoff from the rooftops is managed within the private open space as shown in Figure 69. This site has both villas and multistoreyed apartment buildings that go upto 8 storeys and are surrounded by some open space. The total number of private plots is 177 with an average rooftop area of 275m². Since the typology of the houses differ, the ways to manage stormwater on site may also differ. The villas would probably have more open space and might consider integrating WSUD elements within their gardens or choose to recycle the stormwater for reuse and store in tanks. On the other hand, the apartment buildings might have to simply install tanks underground or opt to also integrate the elements as shown in the section 5.2.3.5. 2m PedestrianPedestrian Bioswale Traffic zoneTraffic zone 2m 4m4m 3m 96 Figure 73: (Top) A view of the Tanner Springs Park in Portland, Oregon, USA. Source: (DREISEITLconsulting 2024) Figure 74: (Left) Interaction between the stormwater runoff and recreational space in the Tanner Springs Park. Source: (Dreiseitl and Land8 2015) Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 97 5.2.3 Hotspot C: Residential Area 5.2.3.1 Description This hotspot is a very common typology in this catchment and as observed, in other parts of Amman. A dense residential block, with no public areas, no public greens and no other function is a tricky site to work with for WSUD interventions. This particular site is at high risk of flooding as seen in Figure 75. To the west is the highway that leads to the Dead Sea, called the Dead Sea Road and has the royal village project on the other side of it. To the south is another main street called the Al-Quds Street of the same width of 50m with some undeveloped land below it. To the north is an 18m wide street called the Prince Hamza Bin Al Hussein Street with commercial buildings on both sides of it. A 24m wide street connects the two highways to the centre of the residential quarter with. The streets within this neighbourhood range between 11m wide to 18m wide, with a lot of dead ends and culde-sacs. All streets are vehicle oriented with little or no pedestrian paths and barely any green space except for the odd tree planted outside houses. The houses in this neighbourhood are classified as type C, which according to (Homes-Jordon 2024), a real estate website, has the following regulations: - Setbacks: front 4m, side 3m, rear 4m - Building percentage: 51 % - Minimum plot area: 500 m² - The minimum length of the façade located on the front street: 18 m² - Number of floors: 4 floors - Height: 16 m. With an open space requirement of 49 %, it is possible to implement raingardens, RWH tanks and so on within the private property, however with only 15 % green space mandatory (Homes-Jordon 2024) , the rest could be paved according to the owner’s interest. There are some undeveloped plots of land but are assigned the landuse of either residential or commercial. For the scenario analysis, the only public space hence available are the streets. Hotspots Areas S1 Private gardens Streets Undeveloped open space Hotspot buildings Residential Commercial Buildings Streets Figure 75: This map shows an overlap of the hydraulic map showing the flows and sinks on the map and showing different functions of buildings and open spaces for the Hotspot C - Residential areas. Source: Author, based on HW, 2024 Dead Sea Road Al Quds Street Prince Hamza Bin Al Hussein Street 98 Legend Residential buildings Private gardens Streets Undeveloped space 5.2.3.2 Identification of types of surfaces and areas As summarized in Table C1 in appendix C, there are no public green areas or existing greens that are taken into account for the calculations. Since most of the residential plots have gardens, they are considered as private open space out of which 40 % is considered green space and 60 % paved as per satellite imagery and the building regulations. The building rooftops are flat and cemented. And the streets are considered entirely to be made of asphalt, as even with pedestrian path, the difference in pavement makes little difference to the calculations. The different types of surfaces can be observed in Figure 76. Figure 76: Map of Scenario 1 - The different surfaces within the hotspot as identified by satellite images in the exisiting conditions. Source: Author, based on GIS analysis, 2024 Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 99 5.2.3.3 Conceptual design of WSUD measures for Scenarios 2 and 3 Since the only public area in this neighbourhood is the streets that also are the most affected in floods and naturally convey and contribute to the runoff, the streets are where all the interventions are planned for this hotspot. Figure 78 describes a recommended street section for the 50m wide streets for the Dead Sea Road and the Al-Quds Street, annotated as street type A, as located in Figure 77. Here, a 9m wide bioswale with varying depths divides the two directions of traffic and has a huge retention capacity, while smaller swales on the two ends divide the inner lanes of traffic from the main 3 lane road. The increase in green space enhances the quality of the street while separating different traffic speeds and does not compromise on the heavy traffic loads. For the Prince Hamza Bin Al Hussein Street (street type C) to the north which narrows down to 18m but has a commercial area on either side of it, can integrate raingardens interspersed in the sidewalks and act as separators of parking spaces as shown in Figure 80. Two streets connect to the inside of the neighbourhood from the main streets and are 24m wide and are designated the street type B. These streets as shown in Figure 79, have a 2m wide swale on either side, separating the pedestrian pathways and the vehicular street. In addition to this, a 4m wide bioswale in the centre separates the two directions of traffic as shown in Figure 78. Lastly, the inner lanes of this neighbourhood range from 11m to 18m (Street type D), so an average of 15m was taken to create the next street section as shown in Figure 81. Since these streets do not have a lot of traffic and have only houses on both sides, in an effort to increase the shade and improve the microclimate of these spaces, green strips have been placed on both ends of the street, which are to be planted with shady trees and local bushes to increase the infiltration. The detailed description of the areas for scenario 2 and 3 are described in Appendix C Tables C1 and 2. For the third scenario depicted in Figure 82, the rooftop runoff needs to be managed within the private properties and should not add to the runoff on the streets. This can be done by installing tanks underground or on the surface of the open space, connected to a diverted spout from the roof. Legend Street A Street B Street C Street D Residential buildings Private gardens Streets Undeveloped space Figure 77: Map showing the layout of different street types and surfaces as per the conceptual design for scenario 2. Source: Author 100 Figure 78: Street type A - section depicting the division of highspeed traffic from the inner lanes through the integration of swales, and a bigger bioretention area in the median of the road. Source: Author Figure 80: Street type C - This commercial street has a two way traffic lane in the middle and 3m wide parking spaces to the sides interspersed with raingardens that separate the pedestrian pathways in front of the shops. Source: Author 50m 24m 2m 2m2m 2m 2m 2m 3m 4m 4m 18m 3m 2m 2m 4m4m 2.5m2.5m 12m 6m 12m 6m 9m 4m Figure 79: Street type B - section depicting the division of vehicular traffic from the pedestrian paths through the integration of swales, and a bigger bioretention area in the median of the road. Source: Author and Gabriela Lugones Guzman Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 101 Legend Street A Street B Street C Street D Residential buildings Private gardens Streets Undeveloped space Buildings with RWH Figure 81: Street type D - section of the inner residential lanes where the traffic is separated from the pedestrian zones though swales that have shady trees to provide a canopy and buffer noise. Source: Author 15m 2m2m 1.5m1.5m 8m Figure 82: Map showing the layout of rooftops with RWH as per scenario 3. Source: Author 102 5.2.3.4 Quantitative Analysis As done for the previous two hotspots, the runoff volumes are calculated for the three scenarios iteratively for rainfall intensity for a period of 24 hours with a 5 year return period. This is done after obtaining the sealed and unsealed areas as shown in Tables C3, 4 and 5 in appendix C. A summary of the results are shown in Table 19 and the comparison is depicted graphically in Figure 83. Here it can be observed that in the current state, a runoff volume of 15635 m³ is accumulated from the neighbourhood. This volume flows towards the Dead Sea Road and to the north of the catchment, ultimately contributing negatively to the flooding of Downtown Amman. However, with the implementation of bioswales in the streets, simply unsealing the area leads to improved infiltration and a reduction of runoff volume to 10045 m³ in the second scenario. But the most significant difference was observed with scenario 3, with the assumption that all the runoff from the roofs is collected in RWH tanks on site, hence causing a reduced outflow from the private properties. The calculated runoff is reduced to 4580 m³ which is less than a third of the volume in scenario 1. Additionally, the runoff rates have also been calculated and summarized in Table 20. As observed from the graph in Figure 84, the runoff rates in scenario 1 are the highest, however, the implementation of WSUD measures in the very limited public space does not quite decrease the rate significantly. Further reduction is observed in scenario 3, hence highlighting the significance of the contribution of rooftop runoff in this hotspot. Table 19: Runoff volumes for the three scenarios Source: Author Table 83: Runoff volumes for the three scenarios Source: Author Duration Rainfall intensity Volume S1 Volume S2 Volume S3 min l/s ha m³ m³ m³ 5 169.02 1515 1274 811 10 123.15 2172 1812 1137 15 107.86 2829 2349 1462 30 83.4 4287 3520 2149 60 63.11 6299 5086 3010 120 47.26 9045 7118.91 4010 180 38.64 10669 8188 4374 360 27.69 13970 10045 4580 720 18.54 15635 9517 2198 1440 10.29 9053 -54 -8175 -2000 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 0200 400 600 800 1000 1200 1400 1600 S1 S2 S3 Duration in minutes Runoff volumes in m3 Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 103 5.2.3.5 Further design recommendations Since the only measures applied in scenario 2 in this case are bioswales and raingardens of similar characteristics, they are clubbed together under the term bioretention, and an average ponding depth of 0.3 has been taken for an estimation of the capacity. With an area of 50250 m², they have a capacity of 15075 m³ in total which is more than the required 10045 m³ for a 5 year event. However, the detailed design of these swales should be done according to the needs and character of the different streets after a more detailed feasibility study. Simply by increasing the unsealed area in a quarter may have the desired effect and adding depths to these measures may not be necessary. It is also observed that after managing the rooftop runoff on site, the runoff volume that needs to be mitigated decreases drastically to 4580m³. These Figure s are summarized in Table 21 which also further shows that the rooftop runoff collected is 5465 m³, which means that for the approximately 300 buildings in this area, around 18 m³ of storage tanks are required for each structure. These storages might be on individual properties or can also be implemented collectively at the end of streets in the cul-de-sacs. However, this is assuming that 100 % of all rooftop runoff is managed within private property, and while this may be a suggestion, making it mandatory by law and introducing building regulations to be implemented may not be fully feasible. Hence, the measures in public areas should be further designed keeping in mind some overflows from private properties as well. Table 20: Runoff rates for the three scenarios Source: Author Table 84: Runoff rates for the three scenarios Source: Author Scenario 1 Scenario 2 Scenario 3 Area (A) 259532.41 222986.96 146841.16 Duration Rainfall Intensity Runoff Rate (Q) min mm/h l/s 5 60.80 4386.72 3769.01 2481.97 10 44.30 3196.25 2746.17 1808.41 15 38.80 2799.42 2405.23 1583.89 30 30.00 2164.50 1859.71 1224.66 60 22.70 1637.81 1407.18 926.66 120 17.00 1226.55 1053.84 693.97 180 13.90 1002.89 861.67 567.42 360 9.96 718.61 617.42 406.59 720 6.67 481.24 413.48 272.28 1440 3.70 266.96 229.36 151.04 0.00 500.00 1000.00 1500.00 2000.00 2500.00 3000.00 3500.00 4000.00 4500.00 5000.00 0200 400 600 800 1000 1200 1400 1600 S1 S2 S3 Duration in minutes Runoff rates in l/s 104 In this hotspot, it can be concluded that due to the minimal public space available, it is necessary for the private spaces to take responsibility for their contribution in stormwater runoff. As observed from the summary of the attenuation capacities of the measures implemented in this hotspot from Table 21, the bioretention systems in the streets will be able to attenuate only the runoff volumes for a 5 year rainfall event. For heavier rainfall events with a return period of 25 years or more, these systems may be able to convey the runoff to an outlet from the neighbourhood, possibly a retention pond. However, if there is not one, the excess runoff that is not attenuated would add to the flooding problem in the catchment. On the other hand, if the rooftop rainwater harvesting systems are installed in the private properties, this vastly reduces the runoff volumes, and even in a 100 year rainfall scenario, the suggested measures have more than enough capacity to attenuate the stormwater, actively helping in infiltration and storage. To incentivise the installation of RWH systems in residential plots, residents need to be made aware of the various benefits of these systems. In a place where people face such a shortage of water, treatment and reuse of stormwater should become the priority and responsibility of everyone. Further, it may be beneficial to also reinstate the additional benefits of integrated WSUD within private properties, like aesthetics and improvement of biodiversity and microclimate. Figure s 85 and 86 show different ways in which rooftop runoff can be managed within the open space of a residence while improving the aesthetics and getting integrated into the landscape. Type of surface Ac,i Depths Calculated Volume Volume capacity Actual Volume m² m m³ m³ Bioretention 50250.53 0.30 15075.16 15075.16 Total volume attenuated in scenario 2 15075 15075 Rooftop RWH 5465 5465 Total volume attenuated in scenario 3 20540 Table 21: Summary of the attenuation capacity of recommended measures Source: Author Runoff Volumes Duration Scenario 1 Scenario 2 Scenario 3 5 years 25 years 100 years 5 years 25 years 100 years 5 years 25 years 100 years min m³ m³ m³ m³ m³ m³ m³ m³ m³ 5 1515 2099 2533 1274 1776 2149 811 1141 1387 10 2172 3019 3652 1812 2539 3084 1137 1616 1974 15 2829 3944 4769 2349 3307 4016 1462 2093 2560 30 4287 6033 7311 3520 5020 6118 2149 3136 3859 60 6299 8917 10849 5086 7335 8995 3010 4491 5584 120 9045 12973 15840 7119 10493 12957 4010 6232 7854 180 10669 15438 18990 8188 12285 15337 4374 7073 9082 360 13970 20778 26013 10045 15894 20391 4580 8431 11393 720 15635 24873 31830 9517 17454 23432 2198 7425 11361 1440 9053 19300 26931 -54 8749 15306 -8175 -2377 1940 Table 22: Comparison of runoff volumes for the three scenarios for return periods of 5, 25 and 100 years. ource: Author Chapter 5: Scenarios in Focus: Analysis of WSUD for Amman 105 house rooftop downpipe into stormwater planter overflow into swale overflow into pond Figure 86: Stormwater planters have been used to create a sheltered outdoor space next to the house. bench seating has been attached to the walls of the planter. Water from the roof travels through the planters into a pond which overflows into a garden swale. Source: Redrawn and adapted from (Dunnet and Clayden 2007) Figure 85: This design aims to create more opportunities for capturing rainwater and then slowly releasing it or using it within the garden. Source: Redrawn and adapted from (Dunnet and Clayden 2007) permeable paving new tree planting swale swale gully swale stormwater planter stormwater planter water butt water butt gully gully pond pond swale swale raingarden raingarden green roof 112 to initially create pilot projects to be implemented in this catchment and monitor their performance. With the help of landscape architects, engineers and urban planners, the suggested measures need to be designed in detail, keeping in mind aesthetic, functional, technical and environmental aspects. A revised landuse map needs to be developed for this catchment, integrating the hydrological aspects along with social and environmental aspects. 6.4 Conclusion The analysis of this thesis outlines the need for integration of WSUD into the policy framework, urban planning and retrofitting of built spaces in Amman. It shows that these strategies not only help mitigate the hydrological vulnerabilities of the city, but also add great value to the urban landscape by improving the microclimate, promoting biodiversity, creating public space for dynamic engagement of the residents and holistically brings nature into the city. The comparison of the different scenarios indicates the high cost of doing nothing, versus the benefits of integrating WSUD into the public and private realms. It shows that even the most impossibly dense areas with minimal potential have the space to integrate these strategies and have great value to be further analyzed. It also shows that while the stakeholders creating policies for climate adaptation realise the need for sustainable drainage systems and have been actively suggesting them in reports for climate resilience and the Green City Action Plan, there is a gap in its implementation, even in the planning document of the urban areas. This gap needs to be covered with the help of capacity building of those responsible for these tasks and involving the community to participate in seeing these tasks through. Prioritizing climate resilience is crucial for Amman, necessitating alignment of its adaptation plan with the national strategy. Enhancing social infrastructure, adopting nature-based solutions, and upgrading critical physical infrastructure are essential for bolstering the city’s capacity to withstand climate-related hazards. With the upcoming challenges such as urbanization, inefficient land use, and zoning, along with the threat of exacerbated inequalities due to uneven resource distribution, and an increased instability in the migration trends, underscore the need for integrated urban planning to create a resilient, green, just, and inclusive city. Chapter 6: Future Horizons: Concluding Insights for Amman’s Stormwater 113 114 Appendix Appendix A: Information on quantitative analysis Table A1: Runoff coefficients of different surfaces Source: DWA-117 (Deutsche Vereinigung für Wasserwirtschaft, Abwasser und Abfall 2013) Table A2: Representative Values for Hydraulic Conductivity of Soils Source: (StructX 2024) 115 Table A3: Water permeability coefficients of loose rock and percolation range for technical drainage Source: (DWA 2006) Appendix B: Additional information for the Royal Village Project Scenario 1A Type of Surface Description Permeable Area Impermeable Area Total Area (Ac) % of total Area m² m² m² Building Rooftops Flat and cemented 2700.47 2700.47 1 % Undeveloped Open Space Space with low or no vegetation and natural soil that has not been developed yet. 450837.052 450837.05 99 % Total 450837.05 2700.47 453537.52 99 % 1 % Table B1: Description of areas in scenario 1A or pre-development scenario of the royal village project. Source: Author 116 Scenario 1B Type of Surface Description Permeable Area Impermeable Area Total Area (Ac) % of total Area m² m² m² Building Rooftops Flat and cemented, both residential and public buildings 104343.65 104343.65 23 % Streets Asphalt 137938.84 137938.84 30 % Paved Area Concrete pavings, sidewalks with closed joints. 92864.37 92864.37 20 % Undeveloped Open Space Space with low or no vegetation and natural soil that has not been developed yet. 0 % Existing Green Areas Private Gardens Areas around residential buildings. Based on satellite imagery, 80 % is assumed to be green, while 20 % is paved for driveways 68159.40424 17039.85106 85199.26 19 % Public Gardens Areas with planted vegetation as per the landscaping masterplan 31754.49 31754.49 7 % Sports grounds Paved grounds with artificial turf 1436.9142 1436.91 0 % Total 99913.90 353623.63 453537.52 22 % 78 % Table B2: Description of areas in scenario 1B or the proposed masterplan of the royal village project. Source: Author 117 Table B3: Description of areas in scenario 2 for the Royal Village project Source: Author Scenario 2 Type of Surface Description Permeable Area Impermeable Area Total Area (Ac) % of total Area m² m² m² Building Rooftops Flat and cemented, both residential and public buildings 48460 48460 11 % Streets Asphalt 113311 113311 25 % Paved Area Concrete pavings, sidewalks with closed joints. 90 % of the area is paved around the school, 10 % is permeable for the existing trees on site 70895 70895 16 % Undeveloped Open Space Space with low or no vegetation and natural soil that has not been developed yet. 0 0 % Exisiting Green Areas Areas with planted vegetation exisitng on site 31754 31754 7 % Private Gardens Areas around residential buildings. Based on satellite imagery, 40 % is assumed to be green, while 60 % is paved. 20062 20062 4 % Public Gardens Areas for public use, with no pavements as per satellite imagery 68159 17040 85200 19 % Blue Green Measures New Green areas Permeable area created out of previously sealed or undeveloped open space 4118 4118 1 % Green Roofs Implementing semi intensive or intensive on flat roofs of all public buildings 55884 55884 12 % Bioswales Shallow pits that are vegetated for retention and conveyance of stormwater 10163 10163 2 % Permeable Pavement Paving blocks with loose joints to increase permeability of the area 14465 14465 3 % Raingarden A landscaped area that captures and filters rainwater runoff 0 % Total 204606 249706 454312 45 % 55 % 118 Scenario 1A Type of surface Ac,i Ψm,i Aimp Ap m² m² m² Building rooftops 2700.47 0.90 2430.42 Undeveloped Open Space 450837.05 0.40 180334.82 Total 453537.52 2430.42 180334.82 Scenario 1B Type of surface Ac,i Ψm,i Aimp Ap m² m² m² Building rooftops 104343.65 0.90 93909.28 Streets 137938.84 0.90 124144.96 Paved 92864.37 0.75 69648.28 Existing Green 31754.49 0.20 6350.90 Public Gardens 0.10 0.00 Private Gardens 85199.26 0.30 25559.78 Undeveloped Open Space 0.00 0.40 0.00 Sports Grounds (Paved) 1436.91 0.80 1149.53 Total 453537.52 288852.05 31910.67 Scenario 2 Type of surface Ac,i Ψm,i Aimp Ap m² m² m² Building rooftops 48459.57 0.90 43613.61 Streets 113311.25 0.90 101980.12 Paved 70895.16 0.75 53171.37 Existing Green 31754.49 0.20 6350.90 Public Gardens 20061.80 0.10 2006.18 Private Gardens 85199.26 0.30 25559.78 Undeveloped Open Space 0.40 0.00 New Green 4118.48 0.10 411.85 Green Roofs 55884.08 0.40 22353.63 Bioswale 10162.85 0.20 2032.57 Permeable Pavement 14464.75 0.30 4339.42 Raingarden 0.10 0.00 Total 454311.68 198765.11 63054.33 Table B4: Calculation of reduced areas for Scenario 1A Source: Author Table B6: Calculation of reduced areas for Scenario 2 Source: Author Table B5: Calculation of reduced areas for Scenario 1B Source: Author 119 Scenario 3 Type of surface Ac,i Ψm,i Aimp Ap m² m² m² Building rooftops 0.00 0.90 0.00 Streets 113311.25 0.90 101980.12 Paved 70895.16 0.75 53171.37 Existing Green 31754.49 0.20 6350.90 Public Gardens 20061.80 0.10 2006.18 Private Gardens 85199.26 0.30 25559.78 Undeveloped Open Space 0.40 0.00 New Green 4118.48 0.10 411.85 Green Roofs 55884.08 0.40 22353.63 Bioswale 10162.85 0.20 2032.57 Permeable Pavement 14464.75 0.30 4339.42 Raingarden 0.10 0.00 Total 405852.11 155151.50 63054.33 Table C1: Description of types of surfaces for the residential area for scenario 1 Source: Author Table B7: Calculation of reduced areas for Scenario 3 Source: Author Scenario 1 Type of Surface Description Permeable Area Impermeable Area Total Area (Ac) % of total Area m² m² m² Building Rooftops Flat and cemented, both residential and public buildings 84,606.44 84,606.44 23 % Streets Asphalt 1,63,843.34 1,63,843.34 45 % Undeveloped Open Space Space with low or no vegetation and natural soil that has not been developed yet. 7,138.09 7,138.09 2 % Private Gardens Areas around residential buildings. Based on satellite imagery, 40 % is assumed to be green, while 60 % is paved. 88,192.96 22,048.24 1,10,241.20 30 % Total 95,331.05 2,70,498.03 3,65,829.08 26 % 74 % Appendix C: Additional information for Residential Area 120 Scenario 2 Type of Surface Description Permeable Area Impermeable Area Total Area (Ac) % of total Area m² m² m² Building Rooftops Flat and cemented, both residential and public buildings 84606.44 84606.44 23 % Streets Asphalt 112070.51 112070.51 31 % Undeveloped Open Space Space with low or no vegetation and natural soil that has not been developed yet. 7138.09 7138.09 2 % Private Gardens Areas around residential buildings. Based on satellite imagery, 40 % is assumed to be green, while 60 % is paved. 88192.96 22048.24 110241.20 30 % Blue Green Measures Bioswales Shallow pits that are vegetated for retention and conveyance of stormwater 50250.53 50250.53 14 % Total 145581.58 218725.19 364306.77 40 % 60 % Table C2: Description of types of surfaces for the residential area for scenario 2 Source: Author Scenario 1 Type of surface Ac,i Ψm,i Aimp Ap m² m² m² Building rooftops 84606.44 0.90 76145.80 Streets 163843.34 0.90 147459.01 Paved 0.75 Existing Green 0.20 Public Gardens 0.10 Private Gardens 110241.20 0.30 33072.36 Undeveloped Open Space 7138.09 0.40 2855.24 Total 365829.08 223604.81 35927.60 Table C3: Calculation of reduced areas for Scenario 1 Source: Author Table C4: Calculation of reduced areas for Scenario 2 Source: Author Scenario 2 Type of surface Ac,i Ψm,i Aimp Ap m² m² m² Building rooftops 84606.44 0.90 76145.80 Streets 112070.51 0.90 100863.46 Private Gardens 110241.20 0.30 33072.36 Undeveloped Open Space 7138.09 0.40 2855.24 New Green 0.10 0.00 Bioswale 50250.53 0.20 10050.11 Total 364306.77 177009.26 45977.70 121 Table C5: Calculation of reduced areas for Scenario 3 Source: Author Scenario 3 Type of surface Ac,i Ψm,i Aimp Ap m² m² m² Building rooftops 0 0.90 0 Streets 112070.51 0.90 100863.46 Private Gardens 110241.20 0.30 33072.36 Undeveloped Open Space 7138.09 0.40 2855.24 New Green 0.10 0.00 Bioswale 50250.53 0.20 10050.11 Total 279700.33 100863.46 45977.70 Appendix D: Miscellaneous Residential land regulation - Provisions for regulating housing areas. All residential groups share similar provisions, but the difference between them is in proportions and numbers, and these provisions are as follows: • Setbacks: It is the space separating the building from the border of the land in which building is prohibited. It includes the front, side, and back directions. • Building Percentage: It is the area on which the landowner is entitled to build in relation to the total land area. • The number of turns • The minimum length of the façade located on the front street • Height: From the ground floor tiling • Parking Provisions of categories of housing areas A, B, C, D 1. Residential area A • Setbacks: front 5m, side 5m, rear 7m • Building percentage: 39 % • Minimum plot area: 1000 m² • The minimum length of the façade located on the front street: 25 m² • Number of floors: 4 floors • Height: 16 m 2. Residential area B • Setbacks: (front 4m, side 4m, rear 6m) • Building percentage: 45 % • Minimum plot area: 750 m² • The minimum length of the façade located on the front street: 20 m² • Number of floors: 4 floors • Height: 16 m 3. Residential area C • Setbacks: front 4m, side 3m, rear 4m • Building percentage: 51 % • Minimum plot area: 500 m² 128