68887 v5 GDLN Seminar on Disaster Risk Management in East Asia and the Pacific – 2010 series – Summary of December 15, 2010 Video Conference Urban Flood Risk Management: Experiences of Cities Speakers:  Mr. Khalifa Ababacar Sall (The Mayor of Dakar City, Senegal)  Mr. Denis Jean-Jacques Jordy (Senior Environmental Specialist, World Bank, Senegal)  Mr. Christian Diou (Senior Municipal Engineer, World Bank, Senegal)  Dr. Ho Long Phi (Senior Adviser/Project Manager at the Steering Center of Flood Control, Ho Chi Minh City, Vietnam) Main moderator:  Mr. Iwan Gunawan (Senior Disaster Risk Management Specialist, World Bank, Indonesia) Key topics discussed: 1. The Causes and Patterns of Urban Flood Risk 2. Current Urban Flood Risk Activities 3. Challenges for Effective Urban Flood Risk Reduction Executive Summary This seminar on Disaster Risk Management in East Asia and the Pacific focused on flood risk management in urban areas. Different experiences and lessons learned from previous disasters (floods) in Dakar, Senegal, and Ho Chi Minh, Vietnam, provided valuable insights into the process of urban flood risk management. Key findings are as follows:  In recent years, urban cities, such as Dakar and Ho Chi Minh, have experienced more recurrent and intense flooding events, particularly in their low-lying areas. The main cause is linked to the ongoing pressures created by rapid urbanisation which has not been accompanied by appropriate levels of infrastructure investment. This has resulted in increased population settling in hazard-prone areas.  Efforts within flood risk management have intensified to address not only the improvement and construction of drainage systems (structural measures), but also to create integrated solutions based on community ownership and consensus. Increasing community awareness and capacity of local authorities to handle flood situations has been recognized as equally important and more effective than just focusing on structural measures for urban flood risk management.  Effective urban flood risk management requires a tight connection between urban planning and flood risk management in order to adequately deal with the impact of urbanisation and a variety of rainfall events.  Finally, effective urban flood risk management requires close coordination among all affected areas, including all responsible municipalities as well as its agencies and departments, in order to support all-inclusive and regionally relevant solutions. 1 Summary 1. The Causes and Patterns of Urban Flood Risk This seminar focused on two case studies from Dakar, Senegal, and Ho Chi Minh, Vietnam, where urban floods have occurred in recent years, causing serious damages and losses. For example, Dakar has experienced large-scale floods in four out of the last five years. To a certain extent, the causes for these disasters may be attributed to climate change. For instance, in Ho Chi Minh the number of heavy rainfall events per year has increased markedly during the last 50 years. While in the 1960s, around 70 heavy rain events, in which the amount of 100mm or more of rainfall poured down during three hours, were recorded, during the last decade, more than 100 of such events had been recorded. Although the average annual rainfall in Dakar is relatively low at 542mm/year, intense rainfall events are increasing, amplifying the risk of flooding because even small rain amounts can immediately create water-logged areas in the city. Ongoing sea-level rise, indirectly caused by climate change, is another hazardous factor affecting both Dakar and Ho Chi Minh cities. Furthermore, in recent years a stronger urban heat island effect has also contributed to an increase of intense rainfall events in Ho Chi Minh. The seminar has demonstrated that climate change effects constitute a less significant factor than the rising pressures on developing flood-prone areas due to rapid urbanisation. Both Dakar and Ho Chi Minh show significant population growth rates in peri-urban areas as well as in low-lying areas which are prone to flooding. In Dakar, the lack of governance in the urban sector has not only led to an uncontrolled urban growth, but also to the occupation of hazard prone low-lying areas which are obstructing the natural flow of storm water run-off. Accordingly, the lack of adequate drainage systems in terms of number of installations and maintenance in both cities is contributing to the rising overall risk of floods. Another major risk factor for floods in Ho Chi Minh is the ongoing land subsidence in many parts of the city due to the extraction of groundwater. In contrast, Dakar does not experience lowered groundwater levels, but rather rising groundwater levels which constrain the percolation of rainwater. The main type of floods in Dakar is characterised by little rainfall (less than one hour of rain, or only 2-3mm of rainwater) which can immediately cause water-logged areas, often persisting for many weeks. Due to the short rain season from July to September, rainwater drains away very slowly through the dry soil. For example, in August 2009 a flooding occurred in Dakar, causing water-logged areas in many parts of the city which lasted for six weeks after the initial event. Following this disaster, a Post Disaster Needs Assessment (PDNA) was conducted. The findings from the assessment report indicate that housing and public infrastructure (schools, health centres, roads, etc.) were the most affected sectors. The total damages were estimated to be more than USD 100 million with 360,000 people affected. 2. Current Urban Flood Risk Management Activities The vulnerability of Ho Chi Minh City to flooding has been taken into account since 1990, which had resulted in the development of numerous small drainage projects supporting the discharge of storm water. Since 2001, in cooperation with the Japan International Cooperation Agency (JICA), bigger urban drainage projects have been planned and undertaken to upgrade the discharge capacity of the storm sewer system. However, so far only 15 percent of the urbanised land has been upgraded at the cost of around USD 1 billion, and it is expected that additional USD 6 -7 billion will be required during the next decade to fully protect the city from flood risks. 2 In 2008, the construction of a polder system in Ho Chi Minh has been approved by the Ministry of Agriculture and Rural Development (MARD) to protect the city from a sea-level rise. However, it has been controversial and so far not implemented. Instead, it has been suggested to adopt a sustainable urban flood management strategy which would not only focus on structural adaptation measures, but would also include community input and consensus when addressing social impacts and uncertainties of climate change. The approach taken in Dakar to alleviate urban flood risk and to address the absence of a drainage master plan hopes to build upon a medium to long-term strategy consisting of structural and non-structural measures, community participation, and involvement of various municipalities. Following the PDNA, , a project, triggered by the 2009 flood in Dakar, was set up which considers urban development, drainage and improvement of rainwater management issues in an integrated manner. In this way, the project contains the following three components: firstly, institutional strengthening and capacity- building (including strengthening of an early-warning system); secondly, development of primary drainage infrastructures, such as alongside roads, but also the maintenance of existing drainage systems (e.g. solid waste removal); thirdly, community participation including education efforts and raising public awareness. 3. Challenges for Effective Urban Flood Risk Management At the administrative level, both Dakar and Ho Chi Minh are aware of the necessity to improve the management of recurrent floods. However, varying interests determine the extent to which urban flood risk reduction is taken into account in urban planning decisions. For example, in Ho Chi Minh, the actual development plan of the city until 2025 suggests an expansion of development activities into low-lying flood-prone areas, which will most likely hamper efforts for effective urban flood risk management. As experienced in Dakar, further challenge facing effective planning for urban flood risk management is the lack of ownership in affected areas, particularly in the peri-urban areas, which do not fall all under the same jurisdiction as the Municipality of Dakar. This means that not every municipality or political leader prioritizes the efforts for urban flood risk management in the same way as the Municipality of Dakar. As a result, there is a lack of responsibility in these peri-urban areas for formulating development solutions which consider the imminent threat of flooding. Moreover, inadequate coordination between institutions within the Municipality of Dakar has also restricted the implementation of the Disaster Risk Reduction (DRR) to create integrated solutions. Similarly, in Ho Chi Minh, city planning needs to be synchronized with flood risk management. During the seminar, representatives from both cities agreed that integrated solutions in urban development decisions, which would link the issue of urban flood risk with urban development, are needed in the planning decision process. Furthermore, they emphasised that effective urban flood risk management requires a regional approach where all affected Municipalities become part of a sustainable long-term strategy. Accordingly, it has been suggested that in the case of Ho Chi Minh a regional Master Plan approved by the central government of Vietnam would be a welcomed step to tackle urban flood risk reduction more effectively. Further Information Organizations  Ho Chi Minh City University of Technology (publications and project reports) 3 http://www.hcmut.edu.vn/en/  World Bank, Senegal Country Office (publications and project reports, Senegal Country Assistance Strategy, etc) http://www.worldbank.org/senegal  World Bank, Vietnam Country Office (publications and project reports, Senegal Country Assistance Strategy, etc) http://www.worldbank.org/vietnam Publication and Reports  Japan International Cooperation Agency, “The detailed design study on Ho Chi Minh City water environment improvement project in the Socialist Republic of Viet Nam�, June 2001 http://lvzopac.jica.go.jp/library/, http://lvzopac.jica.go.jp/external/library?func=function.opacsch.mmdsp&view=view.opacsch.mmind ex&shoshisbt=1&shoshino=0000052006&volno=0000000000&filename=11650298.pdf&seqno=1 4