The Role of Urban Planning and Landscape Tools Concerning Flash Flood Risk Reduction Within Arid and Semiarid Regions (original) (raw)
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Wadi Flash Floods Challenges and Advanced Approaches for Disaster Risk Reduction, 2021
This chapter highlights some substantial questions inquired by researchers to comprehend the flood risks (FRs) that occur in their cities as follows: (1) what is the impact of flooding on urban areas?, (2) what effect does urbanization have on FR?, (3) what are the existing nonstructural and structural mitigation measures for urban flooding?, and (4) What is the role of urban planning and landscape tools in flood risk reduction (FRR) for cities as well as their inhabitants?. The main messages in this chapter could be summarized as follows: (1) Comprehension of both the sources and types of flooding is vital if proper FRR measures are to be determined, (2) Unplanned urban growth could seriously put lives and properties at high risk (3) Land use planning and regulation, and Sustainable infrastructure for stormwater management through landscape architecture are fundamental measures for future FRR (4) The application of the urban planning approach for FRR in arid and semiarid regions has not yet received adequate attention and facing many challenges for its implementation, and finally (5) the combination of structural and nonstructural mitigation measures in spatial planning could be much more effective than using one type of measure alone.
Multifunctional landscapes for urban flood control in developing countries
International Journal of Sustainable Development and Planning, 2007
The urbanisation process changes the natural landscape, generally aggravating flood problems. In developing countries, urbanisation is not always accomplished by the implementation of the adequate infrastructure required. Lack of planning frequently worsens this situation. Focus on urban flood problems has been changing in the last few decades. The traditional approach that basically worked on the drainage net, by canalising and rectifying water courses, is being complemented or substituted by different concepts. One new approach tries to achieve a systemic solution for the basin, with distributed interventions aiming to recover pre-urbanisation flow patterns and combining water quality and quantity control aspects. These modern concepts deal with techniques known as 'best management practices'. In densely urbanised environments, however, it is not always easy to find suitable areas available for construction of detention reservoirs or extensive infiltration measures, for instance. In such a situation, an interesting option may be the use of multifunctional landscapes, in which urban solutions gain additional hydraulic functions, combining urban planning and hydraulic engineering aspects to revitalise urban environments in a sustainable manner. The use of existing parks and squares, remodelled to aggregate permanent or temporary ponds, can be an interesting option for flood control. In developing countries, however, as in the city of Rio de Janeiro, Brazil, water quality problems due to untreated sewage disposal are generally more crucial than those associated with watershed washoff. This article presents a case study related to the urban basin of the Joana River, which is one of the major tributaries of the drainage net of the centre-north zone of Rio de Janeiro city, which contains traditional town districts. The article presents a comparison, in terms of flood levels, between scenarios that consider the present situation and a combination of traditional and alternative flood control measures. This assessment was carried out using a mathematical cell model and the results presented show the potential benefits that can be achieved through the use of multifunctional landscapes with flood control features. This type of solution points to the combining of architecture, urbanism and engineering to help in solving flood control problems in urban environments, especially those that are a reality in developing countries. Finally, the City Hall intervention, which was developed based on the ideas proposed in this article, is presented.
Water Resources Management, 1999
In Part I of this article the very dynamic nature of floodplain management was discussed and the need for modelling the urban growth processes and formulating scenarios of urban development was emphasised. In this second part, the use of Geographic Information Systems (GIS) for addressing those problems is presented. GIS have been recognised as a powerful means to integrate and analyse data from various sources in the context of comprehensive floodplain management. Adequate information and prediction capability is vital to evaluate alternative scenarios for flood mitigation policies and to improve decision making processes associated with flood management. A framework for the comprehensive evaluation of flood hazard management policies is also addressed in this article. This comprehensive approach to flood problems is more than an attitude or a philosophical starting point. It makes use of specific technological tools conceived to be used by different actors, some of them being nonexperts in flood analysis. These tools, based on GIS, are very appropriate for a participatory approach to flood policy formulation and floodplain management because they help communicating with the public in a scientifically correct and yet rather simple manner.
The increasing probability of flood risk in terms of its magnitude and frequency in urban areas prompted man to act for flood mitigation measures. Various flood risk control measures were carried out in different parts of the world but flood events persisted. This paper assessed the main causes of flood risk in urban areas and the various flood risk management measures for flood control so as to come out with a sustainable flood risk mitigation measures for urban areas. Related theories and empirical studies were reviewed as a method to acquire relevant information for analyzing the factors of flood risk and the trend in flood risk mitigation measures. The result points out the inability of both structural and non-structural measures to completely stop flood occurrences. Hence, an integration of the current measures and a partial systematic conversion of land use to its natural state can sustainably reduce flood risk in urban places.
THE ROLE OF URBAN LANDSCAPE IN PREVENTION OF WATER RISK
SU RİSKİNİN ÖNLENMESİNDE KENTSEL PEYZAJIN ROLÜ, 2021
Flood and drought problems have an important place in Turkey as well as on a global scale. Drought and flooding have emerged over the past two decades as the two extremes of the most devastating hydrological spectrum of the climate crisis. These two extremes have caused approximately 600 billion dollars of damage since the beginning of the twenty-first century, affected 3.5 billion people, and caused material and moral losses on a large scale. According to the recently published reports of the Intergovernmental Panel on Climate Change (IPCC), changes in the hydrological cycle caused by climate change will be stronger, leading to longer-lasting droughts and floods. These problems also present the Anthropocene Age as the age when the most important decisions about our future will need to be taken. Detailed studies and meetings are held at global, national and local levels in order to manage disasters in the future. When viewed from a general perspective, natural disasters, which are considered as the main dynamics, and the issues that cause them (such as global urbanization, ecological crises, etc.) can be prevented by many interdisciplinary studies; scientific knowledge, ecological and holistic perspective, creation of flexible/resilient infrastructure, methods that can be adapted according to time and physical situation are all in the direction of minimizing the experienced crises and disaster effects. Landscape discipline also has an important place in the prevention of disasters. Landscape forms the layers of social, societal, ecological services and the transition between everyday experiences and wildlife. At the same time, it plays an effective role in the repair of the destruction and damaged ecosystem parts in cultural and natural areas where human lives are located. Urban landscape analyzes are effective in this repair, especially in the prevention of the destruction that occurs / will occur in the settlements where disasters intensify, or in the post-destructive renewal. There are important solutions to reduce the water risk, which is one of the biggest problems of the climate crisis; landscape designs in sponge cities, technological solutions positioned to prevent floods, permeable materials that can clean and absorb flood water, adoption of xeric landscape design in urban areas, etc. The aim of this study is to understand the role of urban landscape design examples used in preventing water risk in domestic and foreign literature, within the framework of modern technological analysis, and to understand their role in preventing water risk.
Flash flooding as a threat to settlements even in remote areas
Environment & Urbanization, 2016
Desert environments are subject to flash floods in wadi floors, which may occur only once every decade or two in a given wadi (dry channels or valleys, except during rains). In areas of rapid growth, flood-prone areas can become urbanized in the time between floods. Being flat and constituted of sandy sediments, unlike the surrounding terrain, wadi floors are often used for construction, exposing the new settlements to flood risks. We present a case study of the town of El-Sheikh El-Shazli, in the Eastern Desert of Egypt, which has undergone increasingly rapid development over the past two decades. The town is named for an important 13th-century Sufi leader whose shrine receives thousands of visitors annually. We document the extent and effects of the last flash flood (1996) from interviews, field measurement of flood debris, and patterns in satellite imagery; these show the extent of new development in flood-prone wadi floors and the potential risks to residents and visitors in the absence of proper planning. We then recommend measures to reduce the future loss of life and damage from flooding.
Five feet high and rising : cities and flooding in the 21st century
2011
Urban flooding is an increasingly important issue. Disaster statistics appear to show flood events are becoming more frequent, with medium-scale events increasing fastest. The impact of flooding is driven by a combination of natural and human-induced factors. As recent flood events in Pakistan, Brazil, Sri Lanka and Australia show, floods can occur in widespread locations and can sometimes overwhelm even the best prepared countries and cities. There are known and tested measures for urban flood risk management, typically classified as structural or engineered measures, and non-structural, management techniques. A combination of measures to form an integrated management approach is most likely to be successful in reducing flood risk. In the short term and for developing countries in particular, the factors affecting exposure and vulnerability are increasing at
Shaping urbanization to achieve communities resilient to floods
Environmental Research Letters, 2021
Flood risk is increasing in urban communities due to climate change and socioeconomic development. Socioeconomic development is a major cause of urban expansion in flood-prone regions, as it places more physical, economic, and social infrastructure at risk. Moreover, in light of the 2030 Agenda for Sustainable Development by the United Nations, it has become an international imperative to move toward sustainable cities. Current approaches to quantify this risk use scenario-based methods involving arbitrary projections of city growth. These methods seldom incorporate geographical, social, and economic factors associated with urbanization and cannot mimic city growth under various urban development plans. In this paper, we introduce a framework for understanding the interactions between urbanization and flood risk as an essential ingredient for flood risk management. This framework integrates an urban growth model with a hazard model to explore flood risk under various urban development scenarios. We then investigate the effectiveness of coupling nonstructural flood mitigation measures-in terms of urban planning policies and socioeconomic incentives-with urban growth processes to achieve sustainable and resilient communities. Using this framework, we can not only simulate urban expansion dynamics through time and its effect on flood risk but also model the growth of a region under various urban planning policies and assess the effectiveness of these measures in reducing flood risk. Our analysis reveals that while current urban development plans may put more people and assets at flood risk, the nonstructural strategies considered in this study mitigated the consequences of floods. Such a framework could be used to assist city planners and stakeholders in examining tradeoffs between costs and benefits of future land development in achieving sustainable and resilient cities.
A Theory on Urban Resilience to Floods—A Basis for Alternative Planning Practices
Ecology and Society, 2012
River cities require a management approach based on resilience to floods rather than on resistance. Resisting floods by means of levees, dams, and channelization neglects inherent uncertainties arising from human–nature couplings and fails to address the extreme events that are expected to increase with climate change, and is thereby not a reliable approach to long-term flood safety. By applying resilience theory to address system persistence through changes, I develop a theory on “urban resilience to floods” as an alternative framework for urban flood hazard management. Urban resilience to floods is defined as a city’s capacity to tolerate flooding and to reorganize should physical damage and socioeconomic disruption occur, so as to prevent deaths and injuries and maintain current socioeconomic identity. It derives from living with periodic floods as learning opportunities to prepare the city for extreme ones. The theory of urban resilience to floods challenges the conventional wisdom that cities cannot live without flood control, which in effect erodes resilience. To operationalize the theory for planning practice, a surrogate measure—the percent floodable area—is developed for assessing urban resilience to floods. To enable natural floodplain functions to build urban resilience to floods, flood adaptation is advocated in order to replace flood control for mitigating flood hazards.