[HTT14-10] Urban Expansion and Its Impact on the Urban Flood Disaster: A Case Study of Colombo Metropolitan Area, Sri Lanka
Keywords:Urban expansion, urban disasters, flood, geospatial techniques, Colombo Metropolitan Area, Sri Lanka
In recent decades, population growth and economic development have directly affected changes in the urban landscape in cities around the world. These rapid changes are prominent in developing regions in Asia and Africa. Rapid changes of the urban landscape resulted to occur several environmental problems such as weakling air and water quality, increasing urban heat island, rising poverty levels, decrease in agricultural land, increasing demand for urban land, high energy consumption, reducing urban green spaces, increasing vector-borne disease, waste-disposal problems, and rising flash flooding. This study aims to capture the impact of rapid urbanization to increase urban flood disasters in the Colombo Metropolitan Area (CMA). There are three specific objectives, such as; examine the spatiotemporal urbanization pattern and driving factors, capture the urban flood disaster trend based on the historical record, and analyze the negative impact of urban disasters towards the introduction of sustainable urban planning. We have selected 1996, 2009, 2019 as the time point to capture the landscape changes over the 23 years’ time. Landsat data and geospatial techniques, including machine learning algorithms, urban-rural gradient, and statistical analysis, were used to map and examine the landscape change in CMA during the 1996–2009 and 2009–2019 periods. The CMA has been selected as a study area by considering the urbanization pattern of Sri Lanka. CMA shows rapid urbanization over the past few decades and recorded several negative environmental issues. In addition to that, the urban flood has resulted in occurring savior damages to CMA during recent years. Unplanned urban development patterns have been effected to recode savior flood damages on people, the environment, and the economy in CMA. We strongly believe that the findings of this study will help policymakers and urban planners to introduce proper remedial measures to control the damages witch course by the urban flood.