RECLAIMING ECOLOGICAL SUSTAINABILITY OF URBAN STREAMS BY USE OF GREEN INFRASTRUCTURE TECHNIQUES A Thesis Submitted to the Graduate School of Engineering and Sciences of İzmir Institute of Technology in Partial Fulfilment of the Requirements for the Degree of MASTER OF SCIENCE in Urban Design by Selçuk AKSOY July 2016 İZMİR We approve the thesis of Selçuk AKSOY Examining Committee Members: Assist. Prof. Dr. Nicel SAYGIN Department of City and Regional Planning, Ġzmir Institute of Technology Prof. Dr. Adnan KAPLAN Department of Landscape Architecture, Ege University Assist. Prof. Dr. Nursen KAYA EROL Department of City and Regional Planning, Ġzmir Institute of Technology 25 July 2016 Assist. Prof. Dr. Nicel SAYGIN Supervisor, Department of City and Regional Planning, Ġzmir Institute of Technology Prof. Dr. Serdar KALE Prof. Dr. Bilge KARAÇALI Deputy Head of the Department of City and Dean of the Graduate School of Regional Planning, Engineering and Sciences ACKNOWLEDGMENTS I would like to extend my sincerest gratitude to my supervisor Assistant Professor Dr. Nicel Saygın for her excellent guidance, friendly support and encouragement. I would also like to thank Professor Dr. Adnan Kaplan and Assistant Professor Dr. Nursen Kaya Erol for their significant criticisms of my research. Finally, I offer my deepest thanks to my dear family, friends and colleagues for their patience and support. ABSTRACT RECLAIMING ECOLOGICAL SUSTAINABILITY OF URBAN STREAMS BY USE OF GREEN INFRASTRUCTURE TECHNIQUES Ecological sustainability of urban streams has been significantly reversed from the last quarter of the 20th century onwards. This reverse has occurred as a result of increasing urbanisation and human activity, including construction in floodplain areas, relocation and culverting of streams, channelization, riparian clear-cut, and discharge of wastewater into streams. However, on comprehending the significance of urban streams, ecologically-based stream rehabilitation projects have been preferred to hard engineering solutions. These rehabilitation projects not only restore stream ecosystems but also reclaim their contribution to urban landscapes through the provision of ecological, social, and cultural assets. Based on the above, this study sets out to examine urban stream rehabilitation in the context of sustainable water management. In that regard, this research suggests an integrated and holistic approach through green infrastructure tools which can compensate for misguided human interventions on nature, and reclaim ecological sustainability of urban streams and their environs. In line with ecological sustainability, best practices from various countries and the case study of the research evidenced how the degraded stream ecosystem could be rehabilitated by using green infrastructure techniques. The research methodology used in the study involves analysis of the theoretical literature on green infrastructure and stream rehabilitation, best practice analysis, and case study analysis to develop a rehabilitation guideline for Arap Stream and its surroundings. In this sense, the research presents urban-scale, district-scale and neighbourhood-scale rehabilitation strategies for the case study. Finally, the study delivers the rehabilitation plan for Arap Stream that includes in-stream and green infrastructure techniques. Keywords: Stream rehabilitation, green infrastructure, sustainable water management, Arap Stream and its surroundings, urban streams, ecological sustainability iv ÖZET YEġĠL ALTYAPI TEKNĠKLERĠ KULLANIMI ĠLE KENTSEL AKARSULARIN EKOLOJĠK SÜRDÜRÜLEBĠLĠRLĠĞĠNĠN YENĠDEN SAĞLANMASI Kentsel akarsular, son yıllarda yanlıĢ müdahalelere maruz kalarak ekolojik iĢlevselliklerini yitirmiĢlerdir. TaĢkın alanlarındaki yerleĢimlere tehdit oluĢturmaması açısından kentsel akarsuların güzergâhları değiĢtirilmiĢ, beton kanallara alınmıĢ veya yer altına alınarak “ıslah” edilmiĢlerdir. Akarsu ekosistemlerinin zarar görmesi yalnızca ekolojiyi tahrip etmemiĢ, ayrıca kent kimliklerinin ve değerlerinin de yitirilmesine sebep olmuĢtur. Zaman içerisinde yapılan müdahalelerin daha yıkıcı etkilere sebep olduğunun anlaĢılması ile akarsuların ekolojik rehabilitasyonu tüm dünyada gündeme gelmiĢtir. Bu yaklaĢım akarsuların yalnızca ekosistemini iyileĢtirmemiĢ, aynı zamanda kent peyzajına da önemli katkı sağlamıĢtır. Bu çalıĢma, sürdürülebilir su yönetimi çerçevesinde kentsel akarsuların ekolojik ıslahını ele almaktadır. Bu bağlamda, çalıĢma yeĢil altyapıyı bir araç olarak kullanıp kentsel akarsularda yanlıĢ müdahalelerin etkisini azaltan ve aynı zamanda akarsu ıslahını sağlayan bütüncül ve entegre bir anlayıĢı ön plana çıkarmaktadır. ÇalıĢma farklı ülkelerde uygulanmıĢ pek çok baĢarılı örneğin yanı sıra, Arap Deresi ve çevresi için hazırlanan ıslah projesini de sunarak bu sorunlara nasıl çözüm getirilebileceğini ortaya koymaktadır. ÇalıĢmada kullanılan metoda göre, ilk olarak teorik literatür değerlendirilmiĢ, daha sonra uygulanmıĢ projeler irdelenmiĢ ve en son Arap Deresi ve çevresinin analizi yapılmıĢtır. Tüm elde edilen bulgular ile Arap Deresi ve çevresi için Ģehir, bölge ve mahalle ölçeğinde ilkeler geliĢtirmiĢtir. ÇalıĢma aynı zamanda bu yeĢil altyapı temelli ilkeleri kullanarak hazırladığı öneri projesini sunmaktadır. Anahtar Kelimeler: Dere ıslahı, yeşil altyapı, sürdürülebilir su yönetimi, Arap Deresi ve çevresi, kentsel akarsular, ekolojik sürdürülebilirlik v TABLE OF CONTENTS LIST OF FIGURES ....................................................................................................... viii LIST OF TABLES .......................................................................................................... xii CHAPTER 1. INTRODUCTION ..................................................................................... 1 1.1. Problem Definition ................................................................................. 1 1.2. Study Objectives .................................................................................... 2 1.3. Methodology .......................................................................................... 3 1.4. Structure of the Thesis ........................................................................... 6 CHAPTER 2. STREAM REHABILITATION FROM A HOLISTIC PERSPECTIVE .. 7 2.1. Urban Streams and Hydrology ............................................................... 7 2.1.1. Definitions ....................................................................................... 7 2.1.2. Classification of Streams ............................................................... 11 2.1.3. Changing Functions of Streams .................................................... 14 2.2. Green Infrastructure ............................................................................. 17 2.2.1. Elements and Components of Green Infrastructure ...................... 20 2.2.2. Green Infrastructure Practices for Stormwater Management ........ 25 2.2.2.1. Rain Garden ......................................................................... 26 2.2.2.2. Bioswale .............................................................................. 27 2.2.2.3. Green Roof .......................................................................... 28 2.2.2.4. Tree Planting........................................................................ 30 2.2.2.5. Constructed Wetland ........................................................... 31 2.2.2.6. Porous Pavement System..................................................... 33 2.3. Stream Rehabilitation ........................................................................... 35 2.3.1. Rehabilitation Outline ................................................................... 38 2.3.1.1. Water Quality and Climate Settings .................................... 39 2.3.1.2. In-stream Habitat ................................................................. 43 2.3.1.3. Riparian Vegetation ............................................................. 47 2.3.1.4. Stream Connectivity ............................................................ 51 2.3.1.5. Stream Daylighting: Natural Channel Design ..................... 55 2.3.2. Stream Rehabilitation in Turkey ................................................... 57 2.3.3. Key Steps for Stream Rehabilitation ............................................. 59 vi 2.4. Evaluation ............................................................................................ 59 CHAPTER 3. BEST PRACTICES ................................................................................. 61 3.1. Mill River Park and Greenway (Stamford, USA) ................................ 61 3.2. Bishan-Ang Mo Kio Park (Bishan, Singapore) ................................... 65 3.3. Cheonggyecheon Stream (Seoul, South Korea) ................................... 69 3.4. Sanlihe River Project (Qian'an, China) ................................................ 72 3.5. Shanghai Houtan Park (Shanghai, China) ........................................... 74 3.6. Tanner Springs Park (Portland, USA) ................................................. 78 3.7. Qiaoyuan Wetland Park (Tianjin, China) ............................................ 81 3.8. Evaluation ............................................................................................ 84 CHAPTER 4. THE CASE OF ARAP STREAM AND ITS SURROUNDINGS .......... 87 4.1. Characteristics of the Case Area .......................................................... 87 4.1.1. Location ........................................................................................