flood hazard mapping project in asia

Flood Hazard Mapping Project in Asia

August 2003

KIKUCHI RyosukeDirector of 2nd Research Department

Infrastructure Development Institute - Japan

- Overview of Flood Damage -- Overview of Flood Damage -

0

20

40

60

80

100

120

140

1973 to1977

1978 to1982

1983 to1987

1988 to1992

1993 to1997

EARTHQUAKE

DROUGHTand FAMINE

FLOOD

HIGH WIND

LANDSLIDE

VOLCAND

OTHER

Fig.-1 Affected by type of disaster and by period (1973 ～ 1997)

Source ： CRED, “World Disasters Report 1999” Source ： Asian Disaster Reduction Center, “Data book of Asian Natural Disasters in the 20th Century”

Fig.-2 Average occurrence and damage of natural disasters (1975 ～ 1999)

0

50

100

150

200

250

300

1975-1979 1980-1984 1985-1989 1990-1994 1995-1999The average occurrence

The average killed thousands year（／）

The average affected peaple million year（／）

The average damaged property billion dollar year（／）

(Millions)

1.Background

Economic growth, urbanization Explosion of populationConcentration of population and propertyPeople who have never experienced a flood are moving in increasing numbers to flood-prone areas in many countries.Residents are less aware of the threat of floods. They are hardly prepared for floods.Suffering more serious damage once a flood occurs.It is time-consuming and costly to construct flood control facilities to lower the risk of flood damage. It is advisable to enhance local residents' awareness of the importance of flood protection efforts concurrently with the steady development of flood control facilities so that overall flood damage shall be mitigated.

2. History of Japan2. History of Japan(1) Flood Record Maps(1) Flood Record Maps

Published by the Ministry of ConstructionShowing inundated areas during past floods

– With Hyetographs, weather conditions, etc.

1:25,000 – 1:50,000 base mapsDelivered to local government offices, and

mass mediaDisplayed on the billboards of the offices

Flood Record Map for the Tsurumi River Basin

June, 1966

Sept.,1976

Public Acceptance of Flood Public Acceptance of Flood Record MapsRecord Maps

94.4

1.51.7

0.1 2.3

MeaninfulUnmeanigHarassedD.K.No Ans.

Percentage of 4,781 Answers

Public Opinion to Flood Public Opinion to Flood Record MapRecord Map

Indication of present status rather than past records was preferred. (36.9 % 　 of 185 respondents, multiple answer)

Larger and more detailed map to identify individual house was demanded. (25.2 %)

Inundation depth in addition to inundation area was thought necessary. (24.8 %)

More records for other floods requested. (8.3 %)

2.History of Japan2.History of Japan(2) Flood Risk Area Map(2) Flood Risk Area Map

Inundation area and depth Calculation based on a model storm with

150-year return periodCompiled for each river basinPublication through pamphlets,

municipalities’ PR papers, mass media, etc.Map scale of 1:25,000 to 1:50,000

Flood Risk Area Map for the Tsurumi River

Public Acceptance of Public Acceptance of Flood Risk Area MapsFlood Risk Area Maps

91.7

0.81.4

6.1

MeaninglulUnmeanigHarassedD.K.

Percentage of1,883 Answers

Public Opinion to Public Opinion to Flood Risk Area MapsFlood Risk Area Maps

More information was needed.– Larger map for individual municipality

(33 % of 1,799 respondents, multiple answers)

– Inundation areas and depths for more frequent storms (17 %)

– Evacuation sites and routes (12 %)

No official protest was made despite prior concern.

Necessity of a flood hazard map was confirmed.

3. Definition of Flood Hazard Map The “Flood Hazard Map” herein referred to is a map that graphically provides information on inundation, as well as on evacuation in an easy-to-understand format.

The goal is to quickly evacuate local residents in a safe and proper manner in the event of floods.

The map is produced and publicized through a joint effort by those in charge of disaster prevention and those in charge of rivers and hydrology in the respective local municipalities.

4. Purpose○ For local residents

-Raise the awareness of the importance of voluntary disaster prevention efforts and proper evacuation.

- For the prompt and smooth evacuation to avoid injury

○ For local municipalities concerned

-Administrative staff to simulate emergency drills and thus urges local municipalities to develop disaster prevention and preparedness countermeasures.

(Evaluate land use plan, road plan, refuge center and etc.)

(1) Information for Evacuation

・ Predicted inundation area, Inundation depth, Flood concentration

time

・ Historical inundation records

・ Areas to be evacuated

・ Location of evacuation places and routes

・ Dangerous spots on evacuation routes

・ Rules to follow in cases of evacuation

・ Communication channels and systems for information on evacuation

・ Issuance criteria for evacuation warnings

5. Information in Flood Hazard Map

5. Information in Flood Hazard Map

(2) Information for educational use ・ Flooding mechanism ・ Topographic features and flooding types ・ Real danger of flood, Predicted extent of damage ・ Meteorological information ・ Past flood records (rainfall, inundation, and damage) ・ Rules to follow in cases of flood ・ Explanation and directions to use flood hazard maps ・ Preparedness against flood

Hazard Map (Sukagawa City)

Inundation depth (m)

Velocity (m/s)

Limits where evacuation on foot in water is possible

Walking in water is dangerous

Walking in water is possible

Information in Flood Hazard Map

Information in Flood

Hazard Map

Information in Flood Hazard Map

6. Effectiveness of Flood Hazard Map

According to the questionnaire survey conducted immediately after the flood, the effectiveness of the Flood Hazard Maps was satisfactorily verified as stated below: 1) The majority of the local residents referred to the locations of the refuges on the Flood Hazard Maps, and evacuated to the proper refuges.

2) The number of evacuees was 1.5 times more for those who referred to the maps than for those who did not. 3) Residents who referred to the maps commenced evacuation one hour earlier than those who did not.

Flooding in Koroyama City, August 1998

Number ofevacuees

1.5 times

< Number of evacuees six hoursafter notice advice to evacuate >

Those who did not see the Hazard Map

Those who saw the Hazard Map Notice to

evacuateOrder toevacuate

Approximately one hour

Source : “Survey Report on Local Residents’ Reaction during the Rainstorm in Koriyama at the End of August 1988” Katada Laboratory, Faculty of Engineering, Gunma University

7. ESCAP/WMO Typhoon　Committee

Hazard Mapping Project

ESCAP/WMO Typhoon Committee

1.Member (14)Japan, Cambodia, China, The DPR of Korea, Lao PDR, Malaysia, Philippines, Republic of Korea, Singapore, Thailand, Viet Nam, USA, Hong Kong, Macao

2.Compornent(5)① Meteorology, ② Hydrology, ③ DPP(Disaster Prevention and Preparedness),④ Training, and ⑤ Research

The schedule of implementation plan

Time Item Content Note

2002

Feb.

Working Group Meeting in Tokyo

①Discussions on the operational framework for 11 projects②Discussions on the contents of workshop in Manila in July 2002

Done

July

Workshop in Manila and the 2nd Working Group Meeting

①Discussions on the manuals for producing hazard maps② Discussions on the pilot areas

Done

Nov.

The 35th TC General Meeting and the 3rd Working Group Meeting in Thailand

①Reporting on the project implementation② Determination of the pilot areas to be adopted

Done


2003

March

WWF3 in Japan

done

Sept.

Workshop and the 4th Working Group Meeting in China

①Preparation and discussions of inundation record map②Discussions on the evacuation centers and evacuation routes③Discussions on the Warning and Evacuation System

Nov.

The 36th TC Session and the 5th Working Group Meeting in Malaysia

①Reporting and evaluation of project implementation②Discussions on the Warning and Evacuation System


2004

July Workshop①Promulgation②Training

Temp.

2005

July Workshop

①Revision of the Manuals②Expansion of the projects to other river basins

Temp.

2006

July Workshop

①Discussions on the Warning and Evacuation System ② The project evaluation.

Temp.

P ilot projects in Asian Countries(10+2)

Cambodia

China

The DPR of Korea

Lao PDR

Malaysia

Philippines

Republic of Korea

Thailand

Viet Nam

Japan

Myanmar (PANEL)

Pakistan (PANEL)

Concluding Remarks

In Japan and TC countries, the importance of Flood Hazard Maps has undoubtedly been recognized in recent years, and now the preparation of the maps is progressing in a positive direction. It has not been long since their preparation began, and yet various efforts are devoted to producing more advantageous and more effective maps. The experience of producing Flood Hazard Maps

in Japan and TC is hereupon briefly introduced. The respective staffs of the local municipalities involved are highly expected to make their utmost efforts, with marked enthusiasm, in preparing reliable and effective Flood Hazard Maps.

ARIGATOARIGATO

あ　り　が　と　う

Thank 　 you 　 for your attention!

flood hazard mapping project in asia

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