application of mangrove forest for countermeasure against...

copyright (c) 2007 EDM-NIED. All rights reserved

Application of Mangrove Forest for Countermeasure Against Tsunami Disaster

DRH Content Meeting, Kobe, March 12-13, 2007

Dinar Catur Istiyanto

Coastal Dynamic Research CenterAgency for The Assessment and Application of TechnologyJl. Grafika No.2, Sekip, Yogyakarta 55281, IndonesiaPh.:+62-274-586239; Fax.:+62-274-542789e-mail: [email protected]; [email protected] IMPLEMENTATION ORIENTED TECHNOLOGY


PRESENTATION CONTENTS

1. MAJOR ASSETS

2. EXPECTED USERS

3. THE SUBJECTS PROTECTED

4. DRIVING FORCES EVENT

5. FEATURE AND ATTRIBUTE

6. NECESSARY PROCESS FOR IMPLEMENTATION

7. FACILITIES AND EQUIPMENTS REQUIRED

8. RESOURCES REQUIRED

9. APPLICATION EXAMPLESCoastal area in Lhok Nga, Bd. Aceh.Pine trees, housing area, cement factory were completely demolished by Indian Ocean Tsunami of Dec 26, 2004.


MAJOR ASSETS

A set of procedure in determining the design parameter is dictated, including determination of design tsunami wave height and length in the area, extension of mangrove forest, mangrove forest density, and practical direction on mangrove plantation method.

Determination of designed tsunami wave height and length will be conducted by utilizing available historical data or numerical model of tsunami generation and propagation, whereas the mangrove forest parameter will be designed according to the laboratory experiment results’ diagrams.

Practical direction on mangrove plantation methodconsist of engineering methods example, which have been successfully practiced in several areas to increase percentage of growing mangrove.

A snapshot of a very sad man sit down along day in front of his destroyed home ruins in Lahewa District of Aceh, Indonesia. His wife and children were all death swept by Indian Ocean Tsunami of Dec 26, 2004.

This implemented orientation technology has been developing to provide the tool of designing the effective mangrove forest as tsunami damper at the beachaccording to the laboratory results of investigation.


EXPECTED USERS

Policy makers (government executives)

Community leaders

Researchers

■ Standard■ Code■ Reference

■ Planning & Design

■ Application

Government officers in fields

NGO and NPO staffs, business personnel,

etc.

■ Continuous research

Pre-

trai

ned

Prac

titio

ners

Applicationinput

Trainingworkshop

Research Fund

Res

earc

h R

esul

ts

Policy


THE SUBJECTS PROTECTED

Coastal Areas

Infrastructures

Buildings

Human lives

Business and livelihoods

QuickBird Natural Color Image23 June 2004, BAND ACEH

QuickBird Natural Color Image28 December 2004, BANDA ACEH

Heavily Eroded Shoreline

Completely Destroyed Buildings

MissingShoreline

Destroyed port

Death toll


HOW IT WORKS ? (Shuto, 1987)It stops driftwood and other floatagesIt reduced water flow velocity and inundation water depthIt provides a live-saving means by catching persons carried out off by tsunamiIt collect wind blown sands and rises dunes, which act as a natural barrier against tsunamis

QuickBird Natural Color Image23 June 2004, BAND ACEH

QuickBird Natural Color Image28 December 2004, BANDA ACEH

Heavily Eroded Shoreline

Completely Destroyed Buildings

MissingShoreline

Destroyed port

Death toll

THE SUBJECTS PROTECTED


DRIVING FORCES EVENT

Tectonic setting ( red line ) and tsunamis events ( colored circle ) in Asian Countries 1600-2004 (ITDB,2004)

HISTORICAL

1600-2005 282 events

Mostly happened at:

• Western Pacific (Japan, Korea, Philipine, Indonesia, Papua New Guinea, Pacific Islands, and

• Indian Ocean (Indonesia, India, Srilanka, Bangladesh)

High frequency occurrence:

• 1845-1865 : 30 events• 1885-1905 : 33 events• 1985-2006 : 21 events

Total casualties: 361.000 death toll

Biggest events:1883 Krakatau (36.000)2004 Aceh (230.000)

Data Courtessy of Hamzah, 2006



Extensive areas of mangroves can reduce the loss of life and damage caused by tsunamis

2004’ Indian Ocean Tsunami :• The Pichavaram mangrove forest

in Tamil Nadu in India slowed down the waves, protecting around 1700 people living in hamlets built inland between 100 to 1000 meters from the mangroves.

• Also reported similar cases in Penang Malaysia and Srilanka.

• In Nias Island of Indonesia, located close to the epicenter, the damage was relatively low, partly due to mangrove forests that guarded the coastline.

This bamboo house in Lahewa, Nias Island (> 1 km from the coastline) has been saved from tsunami by mangrove belt along the creek.

ITST,2005

ITST,2005


Extensive areas of mangroves can reduce the loss of life and damage caused by tsunamis

2004’ Indian Ocean Tsunami :• In Muaradua, Lhokseumawe,

located about 500 m from coastline, the temporary shelter and houses were founded still stand after the beach hit by tsunami more than 3 m. The owner of the shelter said that when tsunami hit the beach, the spits, coastal forest, and lagoon protected that area.

ITST,2005

ITST,2005

ITDB,2005



Imparsial areas of beach trees can reduce the loss of life and damage caused by tsunamis

This may be the role of beach trees…..

West AcehKERRY SHIEH©2005

waveBangladesh

wave



Mangrove distribution in Asia


( Widjo, 2005)


FEATURE AND ATTRIBUTE

Providing engineering tool for planning coastal protection by using mangrove

Determining incident tsunami wave height and length at the beach for design purpose

◙ Historical Data◙ TUNAMI Numerical Model◙ TSUNAWI Numerical Model◙ COMCOP Numerical Model◙ MOST Numerical ModelHistorical wave height

( Source: ITDB, 2004 )

Length 100 km Width 50 km Dislocation 3.2 m

Tsunami simulation of Flores( Source: CDRC, 2002 )



Determining the requirement of mangrove forest density, mangrove forest width, average height of the trees, alongcoastextension of mangrove forest

HIR

CIR

lB SWL

Daratan

Dasar Hutan Bakau

SWL

Dasar Hutan Bakau

ηIR

d tB eff BtB

LIR

Lautan

( b ) Dimensi Hidraulik Hutan Bakau Saat Meredam Tsunami

KKRR or KKTT = = f f ((εε, , BBLL )),

Where εε = = f f ((KK, , δδ)) and δδ = (= (d+Hd+H )/)/ttBB and BBLL = = B/LB/L




Determining the requirement of mangrove forest density, mangrove forest width, average height of the trees, alongcoastextension of mangrove forest

KR = 0,0872 ln(εBL) + 0,782KT = –0,1644 ln(εBL) – 0,4601

Simulating the tsunami inundation over mangrove protected coastal area




Predicting the risk map of the protected area according to the inundation map and land use economics value

Digital map of tsunami run-up

Digital map of land use

Overlay Process

Zonal map of region with tsunami risks

Loss information

Tabular analysis of region’s

economical loss

PETA

RBI

PETA

LLN

PETA

LPI

SURV

EI

LAPA

NG

AN

TSUN

AM

I C

ATA

LOG

NUM

ERIC

AL

SIM

ULA

TION



Preliminary consultation on the possibility of technology application onto certain coastal area.

Discussion and coordination among stakeholders to consider the implementation

possibility of technology and determine ultimate goal of technology implementation.

Workshop or technical training on the application of technology.

Technology application

Evaluation

NECESSARY PROCESSES FOR IMPLEMENTATION


■ Detail data on the coastal area geophysics (fault, subduction line, sediment material, etc.) and morphology (batimetri, topografi, land use, land cover).

■ Historical data on earthquake as well as tsunami event at and nearby area of consideration.

■ Computer facilities capable of handling numerical simulation.

■ GIS software capable of handling spatial and temporal data processing.

■ Field measurement (survey) equipments

FACILITIES & EQUIPMENT REQUIRED

Very dense dwelling area close to the coastline of Permaan Island near Flores, Indonesia, was attacked by 1992 tsunami. More than 1000 people were dead.


RESOURCES REQUIRED

Expertise :

Oceanografer/Coastal Engineer 1 personMangrove plantation Engineer 1 personGIS software operator 2 personsField Surveyor 3 persons

Organization :

Central Government Ministry of Forestry/Ministry of Marine & Fisheries

Local Government Related OfficesCommunity Community leader, NGO, NPO

Money :

Governmental BudgetPrivate Grant


No projects (intentionally designed for tsunami protection using the proposed design procedure) are

initiated yet the present mangrove plantation target are mainly for reducing coastal erosion

Pictures in the left are photograph of nyamplungtrees, which had been planted between coconut trees

at the coast of Banyuwangi, East Java, soon after tsunami attacked this area in 1994.

APPLICATION EXAMPLE


coastline

bambo/wood bambo/wood

mangrove mangrove

waveMangrove plantation:Sheet pile method

bamboo/wooden sandtrap

planted vegetation

beach profile

planted vegetation

expectedbeach profile

bamboo/wooden sandtrap

mild slope steep slope

under construction after 2 years

Mangrove plantation:Sand trap method

APPLICATION EXAMPLE

Pictures Courtesy of Widjo, 2005


Photograph Courtessy to Kongko, ITST, 2005

application of mangrove forest for countermeasure against...

Documents