Wave Reduction by Mangroves during Cyclones in Bangladesh Implementing Nature-Based Solutions for Coastal Resilience

This paper investigates how mangrove foreshores can be integrated into embankment designs in Bangladesh. The effect of mangroves on surges has already been studied for the design conditions of Bangladesh. However, the impact of wave attenuation by mangroves on embankment designs is not known. A mode...

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Bibliographic Details
Main Author: Mancheno, Alejandra Gijon
Other Authors: van Wesenbeeck, Bregje K., Urrutia, Ignacio, van Ledden, Mathijs
Format: eBook
Language:English
Published: Washington, D.C The World Bank 2022
Subjects:
Online Access:
Collection: World Bank E-Library Archive - Collection details see MPG.ReNa
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100 1 |a Mancheno, Alejandra Gijon 
245 0 0 |a Wave Reduction by Mangroves during Cyclones in Bangladesh  |h Elektronische Ressource  |b Implementing Nature-Based Solutions for Coastal Resilience  |c Alejandra Gijon Mancheno 
260 |a Washington, D.C  |b The World Bank  |c 2022 
300 |a 57 pages 
653 |a Wave Energy Dissipation 
653 |a Environment 
653 |a Environmental Engineering 
653 |a Wave Energy Balance 
653 |a Forestry 
653 |a Mangrove Stability 
653 |a Wave Reduction 
653 |a Coastal Resilience 
653 |a Energy Attenuation 
700 1 |a van Wesenbeeck, Bregje K. 
700 1 |a Urrutia, Ignacio 
700 1 |a van Ledden, Mathijs 
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082 0 |a 330 
520 |a This paper investigates how mangrove foreshores can be integrated into embankment designs in Bangladesh. The effect of mangroves on surges has already been studied for the design conditions of Bangladesh. However, the impact of wave attenuation by mangroves on embankment designs is not known. A model is thus developed to estimate the wave height reduction by a mangrove forest, and how such wave attenuation would influence the design of a landward embankment. Model simulations suggest that mangrove belts with a width between 100 and 1,000 meters (perpendicular to the coast) could provide wave attenuation rates between 7 and 55 percent (compared to a situation without mangroves) at potential afforestation sites identified in previous studies. Such wave attenuation rates would reduce the embankment height by 0.09?0.30 meters, diminish the slope revetment thickness by 13?46 percent, and decrease the wave shear stresses at the embankment toe up to 25?70 percent. Relatively wider mangrove belts not only cause a larger reduction of the embankment design requirements, but also host larger biodiversity and are more resilient against pests and extreme events. The model results are highly sensitive to the mangrove properties, and collecting data on the local mangrove species is recommended to reduce uncertainty in the predictions. Moreover, the results also suggest that trees older than 10?20 years might collapse during storms. Expanding the mangrove stability model, including other pioneer species in the analysis, and exploring the option of canopy pruning are thus advised to ensure the integrity of any future afforestation efforts. Overall, this paper provides a methodology that could be applied to design nature-based solutions in Bangladesh