Policy Research Working Paper 9351 Resilient Shores: Vietnam’s Coastal Development between Opportunity and Disaster Risk Background Paper Coastal Development between Opportunity and Disaster Risk An Assessment of the Coastal Protection System in Vietnam Mathijs van Ledden Tran Thanh Tung Dzung Huy Nguyen Long Thanh Nguyen Global Facility for Disaster Reduction and Recovery & Urban, Disaster Risk Management, Resilience and Land Global Practice August 2020 Policy Research Working Paper 9351 Abstract This paper provides a high-level assessment of Vietnam’s current safety standards need finetuning, especially in areas sea dike system and its prescribed dike safety standards. with high risk and growth. This paper acts as a technical The assessment estimates that 65 percent of the sea dike background paper to the report Resilient Shores: Vietnam’s system does not meet the safety standards and that about Coastal Development between Opportunity and Disaster Risk $2 billion in capital investment is necessary to meet the (Rentschler et al. 2020). standards, mainly in the Red River Delta. It also shows that This paper is a product of the Global Facility for Disaster Reduction and Recovery and the Urban, Disaster Risk Management, Resilience and Land Global Practice. It is part of a larger effort by the World Bank to provide open access to its research and make a contribution to development policy discussions 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 mvanledden@worldbank.org. The 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. Produced by the Research Support Team Coastal development between opportunity and disaster risk: An assessment of the coastal protection system in Vietnam Mathijs van Ledden1, Tran Thanh Tung2, Dzung Huy Nguyen3 , Long Thanh Nguyen2 Global Facility for Disaster Reduction and Recovery, World Bank, Washington DC, USA 1 Contact: mvanledden@worldbank.org 2 Faculty of Coastal Engineering, Thuyloi University, Hanoi, Vietnam 3 World Bank, Hanoi, Vietnam Acknowledgements: This working paper contributes to the report Resilient Shores: Vietnam’s Coastal Development between Opportunity and Disaster Risk (Rentschler et al. 2020). The assessments presented in this paper have benefited from helpful comments, feedback, and inputs by Beatriz Pozueta Mayo, Jun Rentschler, Sophie Anne de Vries Robbé, Johannes Braese, Stephane Hallegatte, Claire Nicolas, Benoit Bosquet, Francis Ghesquiere, and Peter Kristensen. The result of a collaboration between the government of Vietnam and The World Bank, this report would not have been possible without the inputs, feedback, and support of the government of Vietnam, led by Tran Quang Hoai and Nguyen Truong Son, Director General and Deputy Director General of the Vietnam Disaster Management Authority, and with sectoral consultation inputs of relevant agencies at MARD, the Ministry of Construction, Ministry of Finance, Ministry of Natural Resources and Environment, Ministry of Planning and Investment, and Vietnam Electricity. 1. Introduction Vietnam’s low-lying river flood plains, deltas and coastal margins, frequently exposed to natural hazards, are home to 70 percent of the country’s population and many important economic activities. Due in part to the high concentration of population and level of development, riverine and coastal flooding is a serious problem in the deltas and lowlands of coastal Vietnam. This is particularly so in the Red River and Mekong River Deltas, with their vast low-lying areas around or just above mean sea level. Without artificial protection from embankments and dikes, these areas would flood regularly. With flooding the most serious hazard facing Vietnam, in recent decades, the government has recognized the importance of flood mitigation for the country’s continued development and prosperity, investing significantly in structural and non-structural solutions for each region. The government of Vietnam has established a clear strategy for disaster risk management and climate change adaptation, with substantially different approaches in the north, central and southern parts of the country. In the Red River Delta and North Central Regions, it aims to radically prevent floods, and take initiatives in prevent and respond to storm, drought and storm surge. In other words, it aims to completely protect these regions from flooding. In contrast, in the Mekong River Delta Region, its natural disaster prevention, response and mitigation approach is one of “living with the flood”, ensuring safety for sustainable development while also taking initiatives to “prevent storm, thunderstorm, whirlwind, salinity intrusion, drought. Its approach in the Central Region combines proactive disaster prevention and adaptation for development. This mixes the two approaches, protecting the population and important economic areas from the flood, while allowing other less important areas to be flooded to a certain level. Dikes in Vietnam’s coastal zone have been recognized as a central element of coastal defense for several decades. 1 Extensive low-lying regions in the Red River and Mekong River Deltas have a large system of sea and estuary dikes. In these deltas, several provinces — such as Quang Ninh, Hai Phong, Ca Mau and Kien Giang — have over 150 kilometers of sea dikes each to protect the hinterland from coastal flooding. In the Central Region, smaller dike systems provide flood safety for pockets of low-lying areas near the coast. Vietnam’s sea dike system is essential for preventing extensive flooding of livelihoods and assets during high tides and typhoon surge. The total length of the sea dike system in the coastal zone is 2,659 kilometers (figure 1.1). Figure 1.1. Extent of the river and sea dike system in Vietnam’s Delta Regions a) Dike system in the Red River Delta 2 b) Dike system in the Mekong River Delta Source: Based on data from the VNDMA. The Vietnamese government has invested significantly in its sea dike system over the past decade. In May 2009, it issued a decree on strengthening, upgrading and rehabilitating sea dikes 3 in two phases from Quang Ninh to Quang Nam (phase 1) and from Quang Ngai to Kien Giang (phase 2). 2 This national program was divided into three periods with clear objectives for each: • 2009–2012: Planting mangrove forests parallel to the sea dike system • 2013–2016: Upgrading and developing the sea dike system alongside the road network • 2017–2020: Constructing a sluice system to adapt the sea dike system to sea level rise and operate it for transportation. It is widely recognized that the sea dike system is below its established grade level in many places and needs further upgrade. The government has introduced a grade level system for sea dikes that reflects the number of people and area protected. The higher the grade level, the higher the return period for which the sea dike should be able to withstand storm surge and waves. It is widely acknowledged in Vietnam that, due to funding constraints, many sea dikes do not comply with these grade levels. Moreover, the rapid growth in the coastal zone also makes it likely that these grade levels will increase in the near future to mitigate the increased risk to assets and livelihoods. The aim of this technical note is to provide a preliminary assessment of investment needs for Vietnam’s structural coastal protection system — consisting of sea/estuary dikes and revetments — based on the existing data and design standards managed by the Vietnam Disaster Management Authority (VNDMA). The work has been conducted as part of the Increasing Resilience in Vietnam’s Coastal Areas Program 3 under the Vietnam Disaster Risk Management Advisory Services & Analytics. This draft note has been prepared for discussions with representatives from the Ministry of Agriculture and Rural Development (MARD) and other relevant agencies. The assessment and its results have been integrated into the report Resilient Shores: Vietnam’s Coastal Development between Opportunity and Disaster Risk (Rentschler et al. 2020). 2. Data collection and dike safety standards An inventory of all sea and estuary dikes and revetments has been compiled as a basis for this assessment. The dike profile information provided by the VNDMA’s Dyke Management Department was used to produce a detailed list of the characteristics of each stretch of the coastal protection system. Table 2.1 shows an example for Quang Ninh Province. This information is provided for every 1–10 kilometers, and the list includes over 500 stretches of coastal protection, throughout all of Vietnam’s 28 coastal provinces. Where crest height information was not available, this was estimated using the best available data from nearby locations. It is noted that the list provides information about the former flood protection level. 4 A new method of classifying this information has recently been adopted and is used throughout the assessment. It is explained in Section 3. Table 2.1. Overview of coastal protection information used in this assessment Example of a coastal protection stretch in Quang Ninh province 4 Item Example Numbering of the province TT (I–XXVIII), numbering for I.1 each stretch (1,2, etc) Province and location Quang Ninh, dike system in Quang Yen town: Ha An dyke Location by kilometer K0–K8+500 Length (in kilometers) 8.5 Flood protection level according to QĐ 58 (Grades 9–12, Grade 9, Tide 5% Tide 5%) Flood protection level based on new design (Grades I–V) Grade IV Type (sea dike, estuary dike, revetment) Estuary dike Current crest height (in meters) +4.5 ÷ +5.0 The Technical Standards in Sea Dike Design (MARD 2012) have been used to extract relevant information, including the sea dike grade classification (table 2.2). This document provides guidance for the design and rehabilitation of various types of sea dike and other relevant structures in Vietnam and includes information on the grading classification system. The grade determines the safety standard, which depends on the area and population the section protects: the larger the protected area and number of people; the higher the safety standard. In areas of industrial or economic importance, the safety level can be upgraded on a case-by-case basis. The classification system is used to set the safety standard for each stretch of the coastal protection system. Grade I offers protection for a 150-year return period; Grade V for 10–30 years. This assessment has applied a 20-year return period for Grade V as a starting point. Table 2.2 Sea dike grade classification Protected area Population Safety standard Area (hectares, thousands) (thousands) (years) Developed industrial urban Over 100 Over 200 150 area Rural areas with developed 50–100 100–200 100 industry and agriculture Developed rural and 10–50 50–100 50 agricultural area Medium developed rural 5–10 10–50 30 and agricultural area Underdeveloped rural and Below 5 Below 10 10