Introduction
I.1 Purpose of This Publication
This publication emphasizes the need to recognize rehabilitating natural systems with nature based solutions as key for building sustainability and resilience in urban areas.4 It highlights the inextricable link of the two imperatives of resilience and sustainability in town development, as the solutions to one satisfy the needs of the other. This publication describes green infrastructure as nature based solutions for resilience to climate change adaptation for building better and more livable Mekong towns. It is a compendium of resources, ideas, and information sourced from around the world, referenced to allow users to follow through more deeply on topics of special interest. It summarizes in case studies the experience of three Greater Mekong Subregion (GMS) towns—Battambang, Dong Ha, and Kaysone Phomvihane.
The publication provides guidance for wide application of green infrastructure as an alternative and essential adjunct to conventional town infrastructure and development planning.
This chapter distills some of the lessons learned by the three town climate change core groups involved in the project—from Battambang on the Northwest of Tonle Sap Lake in Cambodia, Dong Ha on the central coast of Viet Nam, and Kaysone Phomvihane lying on the Mekong River in Southern Lao People’s Democratic Republic (Lao PDR). The three groups, representing towns facing the full range of climate change challenges found in the GMS, were the central force in conducting the demonstration vulnerability assessment and adaptation planning work of the project. They wished to share some of those experiences with their planning and engineering counterparts in other Mekong towns in the form of consolidated lessons. More detailed lessons learned are provided in each of the town story chapters.
This chapter introduces users to the GMS Climate Resilience in Cities technical assistance project of the Asian Development Bank (ADB). It describes in summary form the Resource Kit for Building Resilience and Sustainability in Mekong Towns, which is the main documented outcome of the project, and how it can guide town planning throughout the GMS.5 It is directed mainly at small and medium-sized Mekong towns but has immediate relevance for any size urban area.
I.2 Trends and Regional Context for the Project
The need for Mekong towns to act now in building resilience and sustainability has never been more urgent. The region is experiencing rapid urbanization with cities expanding five times faster than those in member countries of the Organisation for Economic Co-operation and Development (OECD). In the next 50 years, urban growth in the GMS is expected primarily in small and medium-sized cities and periurban areas along existing and new growth corridors. The GMS, consisting of Cambodia, the Guangxi Zhuang Autonomous Region and Yunnan Province of the People’s Republic of China (PRC), the Lao PDR, Myanmar, Thailand, and Viet Nam, had a population in 2010 of about 320 million, of which less than 25% were urban. By 2030, the GMS urban populations are expected to rise by about 60%, but the large cities in the region will only experience a modest increase of about 30%. The big population increases will be in the smaller cities and towns (Table 1).
The extensive coastline, riverine and low-lying wetland areas, and seasonal variability make the GMS countries especially vulnerable to storms and floods. Short and steep watersheds in the upland areas are also subject to frequent flash flooding and landslides. Despite being under the influence of two monsoon seasons—one from the west, the other from the east—some countries of the region also experience severe drought. Climate change is projected to bring more extreme conditions to the region, increasing the frequency and severity of climate and hydrological events. Sea level rise, storm surge, increased flood levels and duration, and more extensive and unpredictable droughts threaten populations and critical infrastructure across the GMS.
In the GMS, urban development is largely driven by project-level design which fails to adequately consider its functioning in extreme events, area-wide effects and sustainability, and the maintenance of multiple uses of the affected sites. Climate change is rarely taken into account, a situation which is aggravated by the “language gap” between hydrometeorological agencies and infrastructure developers. The information on climate change that is made available is often of little practical use to design engineers and town planners. Even with appropriate spatial information on regular and extreme climate events, area-wide approaches to adaptation planning which assess urban infrastructure proposals as systems rather than individual assets are not normal practice in GMS urban planning.
Climate Resilience in Cities, a 1-year technical assistance project in the GMS supported by ADB, was designed to begin to address some of the constraints to building resilience in small and medium-sized towns. The project culminated in the preparation of this publication by assessing vulnerability of the three project towns and some of their key infrastructure systems and by involving multidisciplinary core groups to plan for climate change and help connect planning and infrastructure design to climatic and site realities.
Engineers and planners in Mekong towns recognize the importance of building sustainability and climate resilience in urban areas. They understand that to do so will require significant changes to current town planning and development decision-making processes and practice. What those changes should be and how to make them remains relatively unexplored in the GMS. This publication, shaped by more than 100 local town planners and engineers from the three towns, helps fill that gap in knowledge and practice.