Planning and design of tsunami-mitigative coastal vegetation belts

Material Information

Title:
Planning and design of tsunami-mitigative coastal vegetation belts
Series Title:
Technical Note of PWRI No. 4177
Creator:
Tanaka, Shigenobu
Catur Istiyanto, Dinar
Kuribayashi, Daisuke
Disaster Risk Reduction Program, Florida International University (DRR/FIU) ( summary contributor )
Place of Publication:
Tsukuba, Japan
Publisher:
International Centre for Water Hazard and Risk Management under the auspices of UNESCO. Public Works Research Institute
Publication Date:
Copyright Date:
2010
Language:
English

Subjects

Subjects / Keywords:
Natural hazards and disasters -- Tsunamis ( lcshac )
Hazard mitigation ( lcshac )
Tree planting ( lcshac )
Genre:
non-fiction ( marcgt )

Notes

Summary:
This report utilizes results from several post-tsunami disaster field investigations to develop general guidelines on the planning and design of coastal vegetation belts for tsunami disaster mitigation. This document is intended for government officers, community leaders and other institutions responsible for developing solutions for coastal disaster reduction. In previous tsunamis, coastal vegetation belts have had various functions in disaster mitigation. They trap debris and other potentially dangerous floating objects, reduce the speed and pressure of water flow, and present a general barrier against the impact of tsunamis. By reducing the run-up and speed of the wave, not only is the area of destruction behind the vegetation reduced, but the time span for evacuation is also lengthened. The document then proceeds to discussing the interaction between characteristics of the tsunami and those of the vegetation belt. Variables such as the wave force, wavelength, and incoming wave direction, along with the number, size, structure, and vegetation combination of trees affect the level of disaster mitigation. The next section focuses on designing coastal vegetation belts, and the importance of determining site suitability, tree size and belt density, along with long-term sustainability. The authors then provide cases of unplanned wave reduction effects of coastal trees in Sri Lanka and Thailand. The final segment of the document is an example of how to plan a vegetation belt using the coastal area of Galle City in Sri Lanka. The authors believe that tsunami-mitigative coastal vegetation belts should be established in combination with other structures, such as seawalls. Despite potential benefits, coastal vegetation belts have little mitigation effects against tsunami inundation higher than five meters, and never provide one hundred percent protection, even at lower inundation heights. Tsunami protection needs to be integrated into the design of coastal area infrastructure development. Another important component of establishing a vegetation belt needs to be sustainability. Selecting vegetation types that address tsunami mitigation along with the economic concerns of the local community enhances the probability of long-term success. Communities should play an active role in the maintenance and cultivation of these structures to ensure ownership. Public understanding and awareness of tsunami dangers and tsunami disaster risk reduction are also significant. ( English )
Subject:
Disaster Risk Reduction ( English )
Scope and Content:
1. Introduction p. 1; 1.1 Objective p. 1; 1.2 Expected users p. 1; 1.3 Limitations p. 1; 2. Roles and limit of coastal vegetation belt in tsunami disaster mitigation p. 3; 2.1 Roles of coastal vegetation belts in tsunami disaster mitigation p. 3; 2.2 Limit of coastal vegetation belt capacity against tsunami forces p. 3; 3. Effect of coastal vegetation belt on tsunami fow p. 7; 3.1 Factors involved in the interaction between tsunamis and coastal vegetation belts p. 7; 3.2 Effects of coastal topography p. 8; 3.3 Effect of vegetation belt density p. 8; 3.4 Effect of vegetation belt width p. 12; 3.5 Considering the effect of gaps a long a coastal zone p. 13; 4. Planning of coastal vegetation belt for tsunami disaster mitigation p. 15; 4.1 Basic Steps in Planning and Design of Tsunami Mitigative Coastal Vegetation Belts p. 15; 4.2 Data requirement and collection p. 15; 4.2.1 Potential tsunami hazard p. 15; 4.2.2 Coastal morphological and tidal data p. 16; 4.2.3 Existing vegetation p. 17; 4.2.4 Land use situations and social conditions p. 18; 4.3 Design parameters and calculation procedures p. 19; 4.3.1 External forces p. 19; 4.3.2 Determination of the width of coastal vegetation belt p. 20; 4.3.3 Selection of tree species p. 21; 4.3.4 Determination of trunk diameter p. 25; 4.3.5 Determination of coastal vegetation belt density p. 27; 5. Combination of coastal forest woth other sources p. 31; 6. Good governance for the sustainability of coastal vegetation-belt p. 33; 6.1 General p. 33; 6.2 The Idea on Sustainable Utilization and Plantation Scheme of Vegetation p. 33; 7. Example of calculation p. 37; 7.1 Description of location and setting of potential tsunami hazard p. 37; 7.2 Setting of protection level and space availability for vegetation belts p. 38; 7.3 Planning of vegetation for tsunami protection p. 39; 7.3.1 Determination of trunk diameter and tree height of vegetation p. 39; 7.3.2 Determination of tree counts p. 40; 7.3.3 Examination of summed diameter (dn = d x n) and flow reduction potential p. 41; 7.3.4 Examination of vegetation thickness (dN all ) and flow reduction p. 42; 7.3.5 Plotting of run-up calculation results on the map p. 44; Aknowledgement p. 47; Bibliography p. 49; Appendix 1: Characteristics of several coastal trees and its protection function related to past tsunami disaster events p. 51; Appendix 2: Examples of forms used in the field investigation of coastal vegetation characteristics p. 55 ( English )
Citation/Reference:
Tanaka, S., Istiyanto, D. C., & Kuribayashi, D. (2010). Planning and design of tsunami-mitigative coastal vegetation belts. International Centre for Water Hazard and Risk Management (ICHARM), Public Works Research Institute (PWRI), United Nations Educational and Scientific and Cultural Organization (UNESCO).

Record Information

Source Institution:
Florida International University
Rights Management:
Refer to main document/publisher for use rights.
Resource Identifier:
FI13042421
743044394 ( oclc )
03865878 ( issn )

dpSobek Membership

Aggregations:
Disaster Risk Reduction