世界银行-孟加拉国沿海圩区全系统防洪标准探讨

Policy Research Working Paper An Exploration of Systemwide FloodProtection Standards for Coastal Polders Ruben JongejanMathijs van LeddenKasper LenderingJasper VerschuurDebashish Paul ShuvraBramka Arga Jafino Urban, Disaster Risk Management,Resilience and Land Global DepartmentNovember 2025 A verified reproducibility package for this paper isavailable athttp://reproducibility.worldbank.org,clickherefor direct access. Policy Research Working Paper11250 Abstract Bangladesh has demonstrated how investment in coastalflood protection saves lives, reduces economic losses, andprotects development gains. Yet, its cost effectivenessdepends on the design standards, which are currentlyselected on a project-by-project basis. This is because atpresent, there is no law, policy, or agency guidance to guideor inform decisions on design standards for coastal poldersin the country. To inform the discussion on appropriateflood protection standards for Bangladesh’s coastal polders,this paper investigates what these standards would look risk to US$18.6 billion investment cost + US$6.7 billionflood risk). This includes the substantial investment in bankprotection needed (~US$5 billion), irrespective of the floodprotection standards, to maintain the alignment of the pres-ent embankments around the coastal polders. Althoughthe absolute values of the economically optimal protectionlevels are subject to considerable uncertainty, a sensitivityanalysis confirms the robustness of the finding that there is This paper is a product of the Urban, Disaster Risk Management, Resilience and Land Global Department. It is part ofa larger effort by the World Bank to provide open access to its research and make a contribution to development policydiscussions around the world. Policy Research Working Papers are also posted on the Web at http://www.worldbank.org/prwp. The authors may be contacted at skazi1@worldbank.org and bjafino@worldbank.org. A verified reproducibility The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about developmentissues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry thenames of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those An Exploration of Systemwide Flood Protection Standards for Coastal Ruben Jongejan; The World BankMathijs van Ledden; The World BankKasper Lendering; The World BankJasper Verschuur; Delft University of TechnologyDebashish Paul Shuvra; The World Bank JEL Codes:Q54, O18, O21, O10Keywords: flood protection, resilience, disaster risk management, optimization, infrastructure planning Acknowledgments:We would like to thank Jolanta Kryspin-Watson, Jun Rentschler, and Dzung HuyNguyen for providing inputs and /or valuable comments that have helped improve this Working Paper. Thisresearch received financial support from the Japan-World Bank Program for Mainstreaming Disaster RiskManagement in Developing Countries, which is financed by the Government of Japan and received 1.Introduction Bangladesh’s coastal zone comprises 139 polders,1housing a population that is expected to grow to 61million by 2050. Established in the 1960s, the polder system was originally designed to protect against tidalflooding and saline water intrusion, ensuring stable livelihoods, agricultural production, and local economicgrowth (Paul & Rashid, 2016). The Government of Bangladesh (GoB) has undertaken several large-scaleinitiatives to enhance the resilience of the coastal population. There has been a series of programs (e.g., theCoastal Embankment Project in the 1960s (Kais & Islam, 2023), the Coastal Embankment Rehabilitation Over the past decades, Bangladesh has demonstrated through all such projects how investments indisaster risk reduction can save lives, reduce economic losses, and protect development gains (World BankGroup, 2022b). A retrospective simulation study, for example, showed that embankments protected 54%of the coastal zone from flooding during the 1998 fluvio-tidal flood (Adnan et al., 2019). Hydrologicalinterventions in coastal polders have also been found to reduce people’s livelihood vulnerability whencommunity involvement is incorporated into their operation (Nath et al., 2019). Studies further show thatcoastal infrastructure projects have had significant impact on agricultural production. The economic While flood protection is vital to disaster risk reduction, alleviating poverty and improving livelihoods,it requires substantial investment. The costs of flood protection infrastructure are strongly influenced bythe choice of the flood protection (design) standard. The coastal embankments were originally built towithstand tidal floods. Nowadays, they are designed to withstand more extreme events. Under CEIP-1, for At present, there is no law, policy or age