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Bamboo breakwatersSite-specific erosion protection and adaptation to climate change

in Soc Trang Province, Vietnam

Dr. Klaus Schmitt, Dr. Thorsten Albers & Arndt von Lieberman

Presented by Phạm Thùy Dương

4th International Conference on Estuaries and Coasts

8 - 11 October 2012, Hanoi, Vietnam

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Outline

1. Introduction

2. Methodology

3. Construction

4. Monitoring

5. Conclusions

1

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2

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Narrow belt of mangrove forest along the coast line

Discharge regime Mekong

Long

-sho

re c

urre

nts

Tidal regime

up to 4 m

Dynamic coast line (process of accretion and erosion up to 30 m/yr)

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4

In some sites the dyke is threatened by erosion.Can we rehabilitate mangroves in such sites to protect the

coast from erosion and storms? 1. Introduction

1. Introduction

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Mangroves grow along sheltered coastline.

Rehabilitating mangroves only possible after the wave energy has been reduced by physical barriers.

Breakwaters: reduce erosion & stimulate sedimentation.

Mangrove rehabilitation in erosion sites

5 1. Introduction

1. Introduction

Appropriate designs based on numerical modelling (which simulates hydrodynamics and shoreline development) to minimise downdrift erosion.

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2. Methodology

Numerical modelling using open source software (SWAN, RMA·Kalypso, GENESIS)*

Use existing data

Field measurements

Physical modelling

(*see www.czm-soctrang.org.vn)

6 2. Methodology

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Physical modelling of wave transmission with the bamboo fence 7 2. Methodology

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3. Construction

Local labour

Bamboo poles

Brushwood bundles

Rattan, jute, stainless steel wire for connections

8 3. Construction – Materials & labours

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9 3. Construction – Installation of one bamboo T-fence, June 2012

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3. Construction

10 3. Construction – Site mapT-shaped bamboo fences in Nopol

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4. Monitoring

Visual control

Photo documentation

Benchmarks

GPS shoreline survey

Mangrove monitoring

Mud density analysis

Wave measurements

11 4. Monitoring

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Wave transmission coefficients derived from physical modelling and field measurements

12 4. Monitoring

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5. Conclusions

15 5. Conclusions

Coastal protection and climate change adaptation measures must be site-specific and appropriate:

based on a sound understanding of natural processes

numerical modelling as part of an integrated approach to coastal area management (ICAM)

testing of innovative approaches (not one solution fits all)

bamboo breakwaters and t-fences are an effective way of coastal protection, create conditions for mangrove rehabilitation in erosion sites.

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5. Conclusions

15 5. Conclusions

1,800 m completed

2,850 m under construction

1,500 m planned

Total of 6,150 m

Current state of construction

Thank you for your attention!