Progress Report

Flood Hazard MappinginThailand

Prepared By: Mr. Somchit Amnatsan
Chief of Water management Branch
Regional Irrigation Office 2Royal Irrigation Department
THAILAND
E-mail: somnatsan@yahoo.com, somnatsan@hotmail.com

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Personal Data
Item A: FHM-related situation in Thailand
A-(1) Current/target situation of FHM in Thailand
A-(2) For making of FHM
A-(3) For disseminating/use of FHM
Item B: For Improvement of FHM research by ICHARM
B-(1) For efficient/effective disaster preventions
B-(2) “Flood Hazard Map Manual" made by ICHARM

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Personal Data••••

Name: Mr.Somchit Amnatsan
Organization (Country): Regional Irrigation Office 2, Royal Irrigation Department,Thailand
Present Post: Chief of water management branch
E-mail: somnatsan@yahoo.com, somnatsan@hotmail.com

Item A: FHM-related situation in Thailand
A-(1) Current/target situation of FHM in Thailand(1)-1 Current stage of FHM in Thailand
Several types of FHM were created in Thailand depend on the area and the objective of maps.
Map types which are available in Thailand are as follows;
A: Location map not including elevation data
B: Location map including elevation data
C: Past inundation area of a single past flood
E: Past inundation area based on simulation
F: Inundation area of the design flood
G: Indication forecast by real time analysis.
(1)-2 The outline of current situation of FHM in Thailand
Many FHM-related projects were developed in Thailand. However, the FHM issue inThailand is in the starting stage compare to Japan. The exact number of FHM-related project
has not been collected.
(1)-3 Examples of good FHM-related projects
The examples of good FHM-related projects are;
1. Development of River Basin Flood Management System by Optimal Reservoir Operation
and Real Time Flood Forecasting and Warning: A Case Study of Pasak River Basin. This
project is the joint study of the National Research Council of Thailand, the Asian Institute ofTechnology, and the Irrigation Development Institute. The project developed the real time
flood forecasting and warning system including the real time FHM for the area in Pasak
River Basin. The system can forecast and provide flood warning 3-4 days prior the floodevent.

Figure1 Pasak River Basin

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2. Flood hazard mapping of Lampang municipality. This project was conducted by theRegional Irrigation Office 2, Royal Irrigation Department under the approval of the National
Research Council of Thailand. The objective of the project is to prepare the FHM of Lampang
municipality to be used as the tool for flood warning in this municipality. The inundation
analysis of this project was successfully completed and ready to be used for flood warning.

Figure 2 Flood Hazard Map of Lampang Municipality
3. Flood hazard mapping in Nan province of Thailand under the Nan river basin. This project
was conducted by the Regional Irrigation Office 2, Royal Irrigation Department and the Asian
Institute of Technology under the sponsor of the Japan Aerospace Exploration Agency(JAXA), Japan. The objective of this project is to prepare the FHM of Nan province for10-year, 20-year, and 50-year flood event. The study area covers the area of Nan municipality
and Phupiang municipality in Nan province. The project will finish on February 13, 2009.
This FHM will be used for improving flood warning system in Nan province.

Figure 3 Flood Hazard Map of Nan Municipality

3(1)-4 Target/necessary stage of FHM in Thailand
The necessary stage of FHM depends on the type and the important of inundation area, e.g.
the rural area and urban area. However, at least the F-type FHM is necessary for the effective
flood warning, and the G-type FHM is the target for the important and complicated area suchas Bangkok.
A-(2) For making of FHM(2)-1 Institutional situation for making FHMThere are no laws in Thailand which indicate about FHM. Moreover, no organization is
assigned to take responsibility in making FHM.
(2)-2 Hydrological/topographical data situation for making FHMHydrological and topographical data in Thailand is available and accurate enough for making
FHM. Many organizations, e.g. the Royal Irrigation Department, the Water Resources
Department, and the Electricity Generating Authority of Thailand have recorded thehydrological data in every river basins of Thailand. The Land Development Department
already developed the digital elevation model (DEM) throughout Thailand. This DEM can beused for inundation analysis. However, the land leveling may be performed for the better
accuracy of FHM.
(2)-3 Problems for making FHM in your country
The know ledges and technologies in Thailand are enough for making FHM. As mentioned
above that there is not any law in Thailand indicating about FHM, and no organizations are
assigned to take responsibility on making FHM. Hence, the only one problem of making
FHM in Thailand is the policy.
A-(3) For disseminating/use of FHM(3)-1 Institutional situation for disseminating/use FHM
The situation of disseminating/use FHM in Thailand is the same as the making of FHM, i.e.
no organizations and no laws related to dissemination of FHM.
(3)-2 Problems for disseminating/use of FHM in Thailand
The problem is the same as (2)-3.
(3)-3 Other how to use FHM in Thailand
The use of FHM in Thailand may differ from other countries due to the characteristic of floodand the attitude of the people. For instance, severe floods usually occur in Japan resulting inhigh awareness of the people to flood damage. Hence, use of FHM by disseminating to thepeople and let them use the FHM as a guideline for evacuation is very suitable for Japan. In
Thailand, the severe flood rarely occurs in the same location, i.e. the frequency of occurrenceis very low. This results in low awareness of the people to flood problem. Dissemination ofFHM to the people may not suitable such that they may throw it away after 2-3 years ofdissemination. At this stage, the use of FHM as a tool for the officials who issue flood
warning and evacuation is the most suitable way of using FHM in Thailand. In conclusion,
the FHM is used for the officials to provide clear flood information such as flood extent andflood depth to the people so that they are able to evacuate on time.

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Item B: For Improvement of FHM research by ICHARM
B-(1) For efficient/effective disaster preventions(1)-1 Saturation level of TV, Radio, Internet and Newspaper in Thailand
In the normal situation the Meteorological Department provide the weather information every
day in the website “www.tmd.go.th”. This weather information is also reported on TV, radio,and newspaper every day. The information of water level in the river can be found in a
website of the Royal Irrigation Department “www.rid.go.th”. If the heavy rainfall is expected
to occur, the weather and water level information is reported every hour in the above
mentioned websites and also reported on TV and radio regularly.
(1)-2 The flow of information related to evacuation in flood
The outline of flood warning system in Thailand is shown in figure 4. In this system, the Thai
Meteorological Department is responsible for rainfall forecasting. The TMD reports therainfall information in several channels such as television, radio, and internet. The head officeand local office of the organization can get this information from above channels. The local
offices of the organizations responsible for water level and discharge collection such as theRegional Irrigation Office and Provincial Irrigation Office collect the data and perform flood
forecasting from all data, then report to their head offices and other local organizations. The
local offices responsible for flood warning, i.e. the municipality office, the provincial office,the provincial Disaster Prevention and Mitigation office, and the Sub-district Administration
Office will issue flood warning and evacuation recommendation to the people in the area of
their responsibility if the flood is expected to occur. The head offices of each organization
may report the situation to the central government directly for special command.
(1)-3 The awareness level for disaster prevention by residents in Thailand.
As mentioned above that the severe floods in Thailand rarely occur in the same location.
Some area may face to floods almost every year but they are usually small floods that thepeople seem to be familiar with them. This makes the people in Thailand have low awarenessto flood. No voluntary disaster prevention organization in Thailand which is settled by thelocal communities as in Japan. However, the Disaster Prevention and Mitigation Department
has set up the “Mister Warning” project to form the team for flood warning purpose. In thisproject the local residents were trained so that they are able observe the rainfall and waterlevel and give the flood and landslide warning to the people in their communities. From thedatabase of Disaster Prevention and Mitigation Department, there are now 7,757 local
residents throughout Thailand were trained to be Mister Warning.
B-(2) “Flood Hazard Map Manual" made by ICHARM
The manual is very useful for making and dissemination of FHM in developing countries.
However, each country may adapt the process so that it is suitable for flood characteristics
and the attitude of people in the country.

Figure 4 Outline of Flood Warning System in Thailand
ReportRainfall observatory

Meteorological Department

RadioInternetTelevision

Water level and discharge
obsevatory

Regional or Provincial
OfficeHead Office

ReportReportCommandFlood Forecasting

Provincial Disaster Prevention
and Mitigation Office

Municipality OfficeCentral Government

Provincial Office

Sub-District Administration
OfficeIssuing flood warning and evacuation recommendation to the area ofresponsibility