世界银行-孟加拉国沿海圩区全系统防洪标准探讨（英）

Policy Research Working Paper11250An Exploration of Systemwide Flood Protection Standards for Coastal Polders in BangladeshRuben Jongejan Mathijs van LeddenKasper LenderingJasper Verschuur Debashish Paul ShuvraBramka Arga Jafino Swarna KaziUrban, Disaster Risk Management, Resilience and Land Global DepartmentNovember 2025 A verified reproducibility package for this paper is available at http://reproducibility.worldbank.org, click here for direct access. Public Disclosure AuthorizedPublic Disclosure AuthorizedPublic Disclosure AuthorizedPublic Disclosure AuthorizedProduced by the Research Support TeamAbstractThe Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank and its affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent.Policy Research Working Paper 11250Bangladesh has demonstrated how investment in coastal flood protection saves lives, reduces economic losses, and protects development gains. Yet, its cost effectiveness depends on the design standards, which are currently selected on a project-by-project basis. This is because at present, there is no law, policy, or agency guidance to guide or inform decisions on design standards for coastal polders in the country. To inform the discussion on appropriate flood protection standards for Bangladesh’s coastal polders, this paper investigates what these standards would look like if they were based on cost-benefit analyses. The analy-sis finds that implementing differentiated flood protection standards across the coastal polders can be a cost-effective strategy for further suppressing flood risks, reducing up to 27.5 percent of the total cost and flood risks (from US$23.4 billion investment cost + US$11 billion flood risk to US$18.6 billion investment cost + US$6.7 billion flood risk). This includes the substantial investment in bank protection needed (~US$5 billion), irrespective of the flood protection standards, to maintain the alignment of the pres-ent embankments around the coastal polders. Although the absolute values of the economically optimal protection levels are subject to considerable uncertainty, a sensitivity analysis confirms the robustness of the finding that there is considerable value in flood protection level differentiation. Flood protection standards are rarely based on economic considerations alone. They could also be informed by the desire to reduce life safety risk or combat poverty. It is recommended that the implica