An Assessment of the Socio-Economic Impacts of Floods in Large Coastal Areas

- Making a Difference – SSccciiieenntttiiifffiiiccc CCaappaaccciiitttyyy BBuuiiilllddiiinngg aanndd EEnnhhaannccceemmeennttt fffoorr r SSuussstttaaiiinnaabblllee DDeevvveelllooppmmeennttt iiinn DDeevvveelllooppiiinngg CCoouunntttrrriiieesss AAnn AAsssseessssmmeenntt ooff tthhee SSoocciioo--EEccoonnoommiicc IImmppaaccttss ooff FFllooooddss iinn LLaarrggee CCooaassttaall AArreeaass Final Report for APN CAPaBLE Project: 2004-CB01NSY-Dutta Asian Institute of Technology i An Assessment of the Socio-Economic Impacts of Floods in Large Coastal Areas 2004-CB01NSY-Dutta Final Report submitted to APN Editors Dushmanta Dutta Mukand Singh Babel Ashim Das Gupta ISBN ©Asia-Pacific Network for Global Change Research www.apn-gcr.org ii Overview of project work and outcomes Non-technical Summary Annual flood events in Asia have tripled with economic losses and human casualties increased by more than five folds in the last 30 years. Majority of the events are concentrated in South Asia (39%) and South-east Asia (30%). High rate of urbanization and population growth in these regions are likely to aggravate the situation, especially in low-lying large cities, which are affected by sea water intrusion. Based on the 2001 study, Intergovernmental Panel on Climate Change (IPCC) predicts that global mean sea level (msl) may rise as much as 88 cm by the end of the 21st century. The coastal zone is expected to be home to nearly 75% of the Asian population by 2025. Large coastal cities like Bangkok and Dhaka have already been facing severe problems due to lower elevation, some parts of which being tens of centimeters below msl. Potentially, sea level rise will have the greatest impacts in these large coastal cities and very few countries have planned the ways to deal with these problems. The project was aimed to assess socio- economic impacts of flooding under climate change conditions in low-lying large coastal cities in South and South-east Asia to assist the policy makers of the region to better understand the vulnerability of fast developing coastal cities under climate variability and socio-economic changes. The major recommendation of this project is the need for a single organization/agency dealing with flood mitigation and which can simultaneously address climate change issues. The need for delineating flood mitigation and management policies from disaster management policy is also suggested. Objectives The main objectives of the project were: i) to gather and analyze existing data and information for developing a GIS database of hydrologic characteristics and socio- economic conditions of the selected cities; ii) to adapt and apply existing tools and methodologies to simulate and assess flooding under long-term climatic change and rise in sea-level; iii) to assess socio-economic impacts and vulnerability using developed tools; iv) to study the links among policy, socio-economic factors and floods and their impacts in the region for urban flood risk management and identify gaps in existing government polices; v) to establish a network of researchers and institutions engaged in research and policy analysis related to flood risk management; and vi) to build capacity and raise public awareness on climate change and its impacts. The project involved contributions from six countries of South and South-east Asia: Bangladesh, India, Pakistan, Sri Lanka, Thailand and Vietnam and received technical assistance from Japan. Selection of urban coastal cities was based on the size, population and social and economic importance, frequency and duration of flooding, tidal effects on flooding and availability of data and information. The selected areas were Meghna Delta (Bangladesh), Mahanadi Delta (India), Karachi (Pakistan), Matara (Sri Lanka), Bangkok (Thailand), and Hue City (Vietnam). Amount received and number of years supported The grant awarded to this project by the APN CAPaBLE Programme was US$ 45,000 for one year period (2004-2005). The project team received supplementary in-kind support equivalent to US$35,000 from the host institute. Work undertaken The following activities were carried out to fulfill the project objectives: Activity I: Establishment of a network of communication: A network of scientists and institutions was established by means of webpage, web-based discussion forum and mailing list from Japan and the six participating countries in the project. This network was used for communication among researchers involved in this project and others for sharing data, information and exchange of know-how. Activity II: Synthesis of existing data and information and development of GIS database: Existing databases of present hydrological characteristics and socio- economic conditions and their future predictions from various regional and global sources like USGS (DEM and land use), IGBP (soil resources), LUCC (land use changes), UNHABITAT, UNSD (urban development), IPCC, GFDL, MRI, and CCSR ii (simulated results of GCM) were collected for the selected case study areas. Together with the existing and compiled information through this project at country level, a comprehensive GIS and temporal database was developed. Activity III: Scenario analyses of floods and its socio-economic impacts: The scenario analysis and socio-economic impact analysis for the case study areas were carried out at AIT with the following three steps: i) Flood inundation simulation: Flood inundation simulations in the case study areas were carried out using UFRA (Urban Flood Risk Analysis model), IISDHM (Institute of Industrial Science Distributed Hydrological Model) and hydrodynamic model developed by the Public Work Research Institute (PWRI) of Japan for analyzing several scenarios for potential sea level rise conditions in 2025, 2050, 2075 and 2100. The other hydro-meteorological datasets were selected from the recorded worst flood event occurred during the past three decades. ii) Estimation of potential growth of urbanization: The spatial distribution of present urban indicators (population, buildings, transportation network etc.) and their projected growth in the selected periods of the case analysis were modeled using the AGENT-LUC model. iii) Socio-economic impacts: Three main sectors (population, buildings, transportation network) were considered for socio-economic impacts. A set of qualitative indices were developed based on questionnaire survey for impact assessment. Utilizing these indices, the impacts of floods on the selected socio- economic sectors were assessed using the results of steps i) and ii) above. A 2-week long brainstorming workshop was held at AIT during 20-31 March 2005 among the collaborators for deliberation and discussion of country based scenario analyses. It provided an opportunity for cross-country interaction and exchange of initial ideas on development of relevant policies and strategies for implementation. Activity IV: Workshop for discussing outcomes and relating them to policy development: A 3 day international symposium was organized at AIT during 23-25 June 2005 for the major collaborators and policy makers of the participating countries to discuss among the participants the outputs of the study and how these can be incorporated into the existing flood disaster mitigation policies and strategies in respective countries for better flood risk management. A full day workshop as part of the symposium was carried out to develop guidelines for incorporating climate change in flood risk management policies and strategies. The symposium proceedings has been published and sent to all the relevant agencies in South and South-east Asia to make them aware of the findings and recommended guidelines for consideration in developing relevant government policies. Activity V: Dissemination of outcomes for raising awareness: Posters on climate change and its impacts on coastal cities have been produced based on the findings of the project and have been distributed to various relevant organizations of the member countries for raising awareness and dissemination of respective case study results. The collaborators have organized pubic fora at local level, where the case study findings have been presented to the stakeholders. Results The results obtained from the scenario analysis of socio-economic impacts of floods due to sea level rise in 2025, 2050, 2075 and 2100 in the selected case study areas provided a comprehensive picture of the vulnerability of the population, buildings and transportation networks of these urbanized areas. Comparative analyses of the outcomes of the scenario analysis in the individual case study areas are made. For the present (2005) situation, it has been found that the Meghna Delta is highly vulnerable, with 83% of the total population and buildings being affected. This is followed by the Hue City, where about 44% of the population and buildings are affected. Whereas the Mahanadi Delta, Karachi and Matara City, having more than 86% of the population and 82% of the buildings in the unaffected zone, are not in the high risk domain. In this extreme flood scenario, the damage on road network is very meager, except in Meghna Delta where whole road system is affected. In 2025, it is observed that about 43% of the population and 77% buildings in Bangkok will be affected by flood. There is little effect on Karachi as 88% iii population and buildings will remain unaffected, and no noticeable impact is seen in case of Mahanadi Delta. While a small impact on road network is observed in Mahanadi Delta area in India, in other cities it remains

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