introduction

Faculty of Coastal Engineering
BED, BANK & SHORE
PROTECTION
Lecturer: Pham Thu Huong

Chapter 1
INTRODUCTION
(3 class hours)

1. General of Viet Nam coast
CONTENT
2. The impacts cause the damages on coastal line
3. Protect or not protect ?
4. Coastal protection structures
5. Working conditions and requirement with coastal
structures
6. How to look at protections ?
7. How to deal with protections ?

Schedule 45B (15Jan – 18May)
15 Jan: Chapter 1
22 Jan: Chapter 2
29 Jan: Chapter 3
05 Feb: Chapter 3 (cont.)
12 Feb: Tet holiday
19 Feb: Tet holiday
26 Feb: Chapter 4
05 Mar: Chapter 4 (cont.)
12 Mar: Chapter 5
19 Mar: Chapter 5 (cont.)
26 Mar: Chapter 6
02 Apr: Chapter 6 (cont.)
09 Apr: Assignment
16 Apr: Chapter 7
23 Apr: Chapter 7 (cont.)
30 Apr: ???
07 May: experiment
14 May: Summary

1. General of Vietnamese Coast
Islands in Ha Long as breakwaters

Dong Chau beach (Thai Binh)

Beach at Tien Giang river mouth (Go Cong)

Sandy beach at Quang Binh

Rocky beach at Hai Van mountain pass

2. The impacts cause the damages
• Natural impacts:
on coastal line
- Winds, typhoons ⇒ bring sand land ward or sea ward
- Tides, salty water ⇒ erosion, rusted steel structures
- Currents ⇒ erosion, creation
- Waves ⇒ erosion, instability of coastal lines, damaging
structures which protect bed, bank and shore
- Chemical impacts ⇒ structures are corroded
- Impacts of organisms

Erosion in Nam Dinh coast

Impacts of organisms
on culvert wall (NamDinh)

Wave action
(Nam Dinh sea dike – August 2006)

2. The impacts cause the damages on coastal line
• Artificial structures impacts:
- Building dams, reservoirs ⇒ reduce sediment transport to
down stream, cause coastal line erosion
HoaBinhdam

2. The impacts cause the damages on coastal line
• Artificial structures impacts:
- Exploiting sand, grave, mineral resources ⇒ inadequate
sediment supply
Exploiting sand in Tan Ba, Dong Nai river

2. The impacts cause the damages on coastal line
• Artificial structures impacts:
- Deforesting, destroying mangroves ⇒ erosion, unstable
coastal line
Mangroves,
Đầm Nại, Bình Thuận

2. The impacts cause the damages on coastal line
• Artificial structures impacts:
-Reclamations ⇒ unstable coastal line
- Canal, culvert system ⇒ Coastal erosion
- Navigation ⇒ damage bank protections

3. To protect or not to protect ?
Floating houses in MeKong River

Protect what ?
- Protect residential area from flood-tides, storm surge
- Prevent wave actions, erosions, slide of the slope
- Other purposes: Navigation, hydraulic works,
aquaculture, tourism, salt production, national defense.
- Prevent salt intrusion*
- Prevent sedimentation at river mouths and obstacle
on draining off flood away*
* don’t mention in this lecture note

4. Coastal protection structures
- Construction: Sea dikes, revetments, groins,
breakwaters, close-dams, sea-walls, artificial dredging
and creating, dams, culverts,…
- Non-construction: sand nourishments, mangrove
forests, laws, policies, institutions, organization
methods and managements; propaganda, education,
convincing people…

5. Working conditions &
requirement with Coastal structures
- Working conditions of coastal structures:
• Coastal structures are under the powerful influence of
waves, winds, tides, currents, uplift pressures, drifts…
• erosion, accretion
- Requirement with Coastal structures:
• Height Allow overtopping ỏ Not ?
• Stable
• satisfy other purposes

6. How to look at protections?
When and Where ?

Building codes in eroding coastal line

Hue

Examples of protection

7. How to deal with protections?
Cause and effect

Designed protections

North coast Java

Failure Mechanisms

Fault tree

Load and strength for steel and granular structure

Strength increase or load reduction

Strength as a function of time and maintenance

The end of Chapter 1

Construction

Non – construction