Cooperative Research Report of
Public Works Research InstituteNo.366

Report on Japan-Thailand-China Joint
Symposium on Current Policy andDirections on Flood Damage Mitigation

March 2007

Public Works Research InstituteJapan Science and Technology Agency

Copyright © (2007) by P.W.R.I.
All rights reserved. No part of this book may be reproduced by any means,nor transmitted, nor translated into a machine language without the written permission of
the Chief Executive of P.W.R.I.
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Cooperative Research Report of
Public Works Research InstituteNo.366

Report on Japan-Thailand-China Joint
Symposium on Current Policy andDirections on Flood Damage Mitigation
Editors
Junichi Yoshitani
Katsuhide Yoshikawa
Yoshiki Motonaga

Public Works Research Institute (JST/CREST)
College of Engineering, Nihon University (JST/CREST)
Chuo University (JST/CREST)

OutlineAs a research activity of JST/CREST Basin–wide Policy Scenario Study Project led by Prof.
Kengo Sunaga, Yamanashi University, sub-themes for Chao Phraya River Basin and ChanjiangRiver Basin Case Studies hold a Japan-Thai-China joint symposium on Current Policy andDirections on Flood Damage Mitigation with support of several local organization. This is therecord of this joint symposium.

Keyword: Flood, Policy scenario, Chao Phraya River, Chanjiang River, Ayase River,
Tsurumi RiverForeword
This symposium was organized jointly by CREST (Core Research for Evolutional
Science and Technology) project and Thai Hydrologist Assembly in corporation withmany Thai organizations. CREST is a scientific project funding mechanism in Japan
Science and Technology Agency (JST) supported by the Japanese Government and oneof the CREST projects is “Basin-wide Water Policy Scenario in Monsoon Asia” led by
Prof. Kengo Sunada at the University of Yamanashi. This project focuses on water
policy case studies in river basins in Monsoon Asia, two of which are Chao Phraya
River Basin, Thailand and Chanjiang (Yangtze) River Basin, China. The former study
is led by Prof. Katsuhide Yoshikawa at Nihon University and the latter is led by Mr.
Junichi Yoshitani of Public Works Research Institute. These two study groups holdjoint symposium in the past, as both have a lot of common on flood problems,particularly land use management in highly urbanized mega-cities. We started this typeof symposium in Tokyo with our colleagues in Thailand and China. This is the first
symposium held out of Tokyo. We believe this symposium report is beneficial to shareexperience and views on flood management among countries with similar problems.
Katsuhide Yoshikawa, Nihon University
Junichi Yoshitani, PWRIV

CONTENT
1. Program..................................................................................................1
2. On Flood Damage Mitigation in the Basins of Gently-Flowing
Rivers on Low-Lying Plains ..................................................................5
3. Recent Progress in Flood Management in China.................................23
4. Best Practices Found in China’s New Flood Management..................33
5. Policy Evaluation of Comprehensive Flood Control Program inJapan ....................................................................................................39
6. Rainfall Estimate Based Satellite Images and Conceptual
Framework of Its Application for Flood Landslide Early Warning .....47
7. Flooding Situation & Mitigation Measures in Thailand ......................65
8. The Current Situation (Oct. 2006) on Flood Management in Chao
Phraya River ........................................................................................73
9. Bangkok Drainage and Flood Control System ....................................87
10. Flood Situations for the next 30 days of Lower Chao Phraya
River Basin ..........................................................................................99
11. Questions and Discussion ..................................................................109

VI

VII

1.

ProgramSymposium on Current Policy and Directions
on Flood Damage Mitigation
14 October 2006
Royal River Hotel, Bangkok, Thailand
Organized byThai Hydrologist Assembly and CREST/JST
Supported by
Royal Irrigation Department
Department of Water Resources
Department of Public Works and Town & Country Planning
Thai Meteorological Department
Bangkok Metropolitan Administration
The Environmental Engineering Association of Thailand
ASDECON CORPORATION CO., LTD.

OBJECTIVE
Rapid population growth and an expanding scope of human activities that began in the latter half ofthe 20th century gave rise to a wide variety of water issues. Among several water issues increased
flood damage is the common and most important problem in many countries in Monsoon Asia. As
many countries in this region experienced the limitation of traditional flood management
approaches, the more fundamental management for land use and its coordination with flood
management policy has been highlighted. This symposium aims to exchange country level policy
shift implications on flood damage mitigation with a focus on integration of land and flood
management programs and practical implementation in Thailand and some other countries in
Monsoon Asia.
1

PROGRAM
8.30-9:15

Registration

9:15

Opening

Chairperson: Mr. Junichi Yoshitani, Public Works Research Institute of Japan
9:15-9:30

Opening addresses by representative of Vice president of Thai Hydrologist
Assembly and representative of CREST/JST[Report from China and Japan]
9:30-10.00

On the Comprehensive Flood Damage Mitigation in the Basins ofGently-Flowing Rivers on Low-Lying Plains,
Mr.

Katsuhide

Yoshikawa,

Nihon University, Keio

University/Kyoto

University
10.00-10:20

Recent Progress in Flood Management in China,
Mr. Cheng Xiaotao, China Institute of Water Resources and Hydropower
Research

10:20-10.45

Break

10:45-11:05

Best Practices Found in China’s New Flood Management
Mr. Junichi Yoshitani, Public Works Research Institute of Japan

11:05-11:25

Policy Evaluation of Comprehensive Flood Control Program in Japan
Mr. Minoru Kuriki, Public Works Research Institute of Japan

11:25-11:50

Question and Discussion

11:50-1:00pm Lunch
Chairperson: Mr. Subin Pinkayan, Vice president of Thai Hydrologist Assembly[Report from Thailand]
1:00-1:30pm Rainfall Estimate Based Satellite Images and Conceptual Framework of Its
Application for Flood Landslide Early Warning
Ms. Saisunee Bhudthakuncharoen, Mahanakorn University
1:30-2:00pm Flooding Situation & Mitigation Measures in Thailand
Mr. Siriphong Hangsapruek, Director General of Department of Water
Resources
2:00-2:30pm The Current Situation (Oct. 2006) on Flood Management in Chao Phraya RiverBasin
Mr. Suwit Thanopanuwat, Professional Engineer for Planning of Royal
Irrigation Department
2:30-2:50pm Break
2:50-3:20pm Bangkok Drainage and Flood Control System
Mr.Teeradej Tangpraprutgul, Former Director of Drainage and Sewerage2

Department
3:20-3:40pm Flood Situations for the next 30 days of Lower Chao Phraya River Basin
Pornsak Suppataratarn, ASDECON Corporation
3:40-4:30pm Questions and discussion
4:30-4:40pm Closing Remarks by Mr. Kasemsan Suwarnarat, Chairman of the Board
Directors, Waste Water Management Authority

DATE AND VENUE
The symposium will be held on Saturday, 14 October 2006 at the Royal River Hotel,
219 Soi Charansanitwong 66/1, Charansanitwong Road, Bangplad, Bangkok 10700, Thailand;phone 66-(0)-2422-9222, fax 66-(0)-2433-5880.

LANGUAGE
The official language in the symposium is English.

REGISTRATIONThe registration is free of charge. Participants from out of Thailand shall register your full name,organization, and email address by email to Mr. Junichi Yoshitani (yositani@pwri.go.jp).
Participants from Thailand shall register to Thai Hydrologist Assembly by email to Dr.Piyaporn
Songprasert (piyapornna@yahoo.com or tik_pooh@hotmail.com ) The deadline is October 12.

3

4

2.

On Flood Damage Mitigation in the Basins ofGently-Flowing Rivers on Low-Lying Plains
Katsuhide Yoshikawa
Professor of Nihon University
I will report on comprehensive flood damage
mitigation measures for gently-flowing river

On Comprehensive Flood Damage Mitigationin the Basins ofGentle-Flowing Rivers on Low-Lying Plainsbasins on low-lying areas.

14, Oct., 2006
Prof.,Dr. K.Yoshikawa
Nihon University
Keio University/ Kyoto University

As you can see from this slide, the contents ofContents

my presentation are divided into four sections:(1) A fundamental theory and basic flood damage
mitigation measures(1) Setting out a fundamental theory with(2) Implementation of comprehensive flood damage
mitigation measures ;respect to alleviating flood damage andthe eastern suburbs of both the Tokyo and Bangkok metropolitan areas

outlining basic flood damage mitigation(3) Non-structural measures, particularly land use
guidance and regulations

measures(2) Report on the implementation of(4) Conclusion:

comprehensive flood damage mitigation

the effectiveness of comprehensive flood damage mitigation measures

measures in river basins that have experienced
rapid urbanization in the eastern suburbs ofboth the Tokyo and Bangkok metropolitan areas(3) Discussion of non-structural measures,
particularly land-use guidance and regulations(4) Conclusion: verifying the effectiveness ofcomprehensive
measures5

flood

damagemitigation

1.Theory :formulae

D = D⎛⎜ F , F , S ⎞⎟0 ⎠⎝∞D = ∫F P (F )⋅D⎛⎜ F , F , S ⎞⎟dF
0 ⎠
⎝
0 r

This slide outlines a basic theory with regard to（１）

alleviating flood damage. Basically, the total（２）

flood damage [D] is calculated based on

D：Total damage，F：External forces (factors such as rainfall, flow, water level)，
S：Potential damage，F0：Capacity of flood mitigation facilities，
D bar ：annual average damage，Pr(F)：Probability density function of external force

external forces in the form of rainfall, thecapacity of flood damage mitigation facilities

2.Variation of Flood Dmagae⊿D =and the social structures susceptible to flood∂D∂D⋅ ⊿F +⋅ ⊿S + ε ⎛⎜ ⊿F ,⊿S ⎞⎟ （３）
0
⎝
⎠
0 ∂S
∂F
0

damage [S], as shown in Formula (1).

Basic flood damage mitigation measures①Structural Measures （F0 improvement measures ）② Structural Measures (S reduction or limitation measures)③A combination of ① and ②

S

therefore represents the potential flood damage.
The D bar indicating annual average flood
damage is calculated by multiplying andintegrating the probability density function[Pr(F)] of external forces [F], as shown in
Formula (2). The increase or decrease in annual
average flood damage is then calculated using
Formula (3).

This basically explains changes

in the total flood damage; while reinforcing F0
by installing flood damage mitigation facilities
will reduce the total damage, a rise in thepotential flood damage will increase the total
damage.
Consequently, measures that can be used to

Flood Damage Mitigation Measures

reduce flood damage are as follows.

(1) Structural measures :(1) Structural measures to increase the capacity

to increase the capacity of flood damage mitigation facilities[F0]of flood damage mitigation facilities [F0] .

(2) Non-structural measures:(2) Non-structural measures to limit any

to limit any increases in the number of social structures
susceptible to damage (the potential flood damage S )increases in the number of social structures(3) Comprehensive measures :combining both structural and non-structural measuressusceptible to damage: the potential flood

Comprehensive flood damage mitigation
measuresdamage S.
(3) Comprehensive measures combining both
structural and non-structural measures:
Comprehensive flood damage mitigation
measures.
In river basins undergoing rapid urbanization,
comprehensive

flood

damagemitigation

measures are considered effective from a socialand economic standpoint.

6

This

slide

comprehensive

outlines
flood

the

aforementioned

damagemitigation

measures, which consist of a combination of
structural and non-structural measures.

As

shown on the right hand side of the slide,comprehensive measures are made up of
measures to control the flow of flood water,
measures relating to land-use guidance andFig.1 Comprehensive Flood Damage
Mitigation Measuresregulations and other measures designed tolimit damage.

The Flood Damage Mitigation
Program for the Naka/Ayase
River BasinIn this next section, I will examine thecomprehensive

flood

damagemitigation

measures implemented in the Naka/Ayase River
Basin in the eastern suburbs of the Tokyo
metropolitan area. The author supervised thedesign, planning and finalization of this projecton site.

Population (thousand)This slide shows increases in population in theTokyo metropolitan area. Over the course of the

35000
30000

Tokyo

century, the area’s population has increased

Chiba
25000

Saitama

防空計画（1943）

Kanagawa
20000

Total
東京緑地計画（1939）

from approximately 5 million to around 35

復興計画（1948）

15000

million.

10000
5000
0

1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

Year

Fig.2 An Increase in Populationof Tokyo Metropolis

This slide outlines the growing extent of
荒川

江戸川

urbanization during the last hundred years. The

荒川

江戸川

black areas are urban areas. On the right you
can see the current situation in Tokyo,
隅田川

多摩川

100 years
ago Meiji Era

隅田川

compared to the urban areas roughly 100 years

多摩川

ago on the left.
Present

Fig. 3 The Expansion of Urbanized Areasof Tokyo Metropolis (Black Areas)

7This slide shows satellite photographs of urban
areas taken in 1972, 1980, 1990 and 2000,
underlining the rapid progress of urbanization
1972/11/26

over the course of the latter half of the 20th

1980/11/11

century.

1990/11/5

2000/11/24

森林
田畑・草地
人工構造物
河川・湖沼等
その他

Fig. 4 The Expansion of Urbanized Areas
from 1972 to 2000 (Red colored areas)

This slide shows the extent of the Naka/Ayase
River Basin in the eastern suburbs of the Tokyo
The Naka/Ayase
River Basin

metropolitan area, which I will come back to ina moment.

森林
田畑・草地
人工構造物
河川・湖沼等
その他

Fig.5 The Naka/Ayase River Basin:
The Eastern Sub-urban Area of Tokyo Metropolis
Fig.6 The Disappearance of Rivers, Streams and Marshy Lands

As you can see in this slide, a large number of(Around 1907 and 2001)

rivers and waterways have disappeared fromthe Tokyo metropolitan area in line with theprogressofurbanization.

The

rivers,agricultural waterways and canals marked in
red on the diagram on the left have all
disappeared, being turned into undergroundsewers or reclaimed to build roads or otherfacilities. This is another factor that has
increased flood damage.

8

This slide shows the progress of urbanization
along the Naka/Ayase River Basin, going from1955, to 1965, 1975 and finally 1985.
１９５５

With the onset of serious problems due to flood

１９６５

damage as a result of the rapid urbanization ofFig. 7(a) The Urbanized
Areas of the Nalka/
Ayase River Basin(Red Color)

１９７５

the river basin, the national, metropolitan andlocal authorities in the river basin agreed to set
out and implement a plan for comprehensive

１９８５

flood damage mitigation measures in 1983.
This slide shows the progress of urbanization
along the river basin after that point, indicatingurban areas in 1990 and 2000. Urbanization
１９９０

continued even after the formulation of flood

２０００

damagemitigationplans,

with

rapid

urbanization during the period from the 1980s
Fig. 7(b) The Urbanized Areas of the Naka/
Ayase River Basin (Red Colored areas)

to 1990s in particular.

This slide shows a simplified version of a floodland-form
geo-morphologicalclassification

map,

map,

the

indicating

characteristics of the land along the Naka/Ayase
Fig. 8 The Geomorphologicalmap for the
Naka/Ayase River
Basin

River Basin in terms of flood damage
mitigation. The river basin is made up largelyof alluvial plains formed by flooding from theTone, Arakawa and Watarase rivers and has
always been an area susceptible to damage
from flooding.

The other parts of the basin

apart from the alluvial plains consist of loam
plains formed by deposits of volcanic ash.
Although the land was previously used forpaddy and dry fields, subsequent urban
development led to the urbanization of the river
basin.

9

This slide outlines the comprehensive flood
damagemitigation

measures

implemented

along the river basin, as mentioned previously.

Fig.9 The Comprehensive Flood Damage Mitigation
Measures for the Naka/Ayase River Basin

This slide classifies the river basin into threeareas; flood water retention areas made up of
woodland and fields that accumulate rainwaterand allow it to infiltrate, flood water retarding
areas made up of paddy fields that help to store
flood

water

and

to

control

flooding.

Low-lying areas that are protected as urban
Fig.10 The Classification & Designation of the Naka/
Ayase River Basin into Three Areas (1983); Retention, Retarding and Low-lying Areas

areas.
The comprehensive flood damage mitigation
measures essentially restricted urbanization topreserve water retention and retarding areas inan effort to preserve the river basin’s natural
flood retention and retarding capacity and, as
an essential part, not to increase the potential
flood damage.

The plan was to prevent any

increase in Potential flood damage as a result ofdevelopment in such areas. In low-lying areas,
the plan was to implement flood damage
mitigation measures to protect against flooding
and encourage urbanization to remain withinsuch areas.
This slide outlines the structural measures
implemented. These basically consisted ofmeasures in line with the characteristics of theriver basin, in view of the river’s increased
outflow capacity and the fact that it is agently-flowing river in a low lying area, andincluded measures to drain the flow of flood
Fig.11 Structural measuresin the Naka/Ayase River Basin

water

10

throughmultiple

bypassdrainagechannels and reduce the downstream flow ofwater, measures to drain flood water using
drainage pumps and measures to retain andregulate levels of flood water based on the
installation of retarding basins as structural
measures.
This slide indicates urbanization promotion
areas under land-use plans, a key part ofnon-structural measures.

In addition tourbanization promotion areas, there are alsourbanization control and adjustment areas
subject to restrictions or limits on urbanization.
The slide shows urbanization promotion areas

Urbanization Promoting Area in 1978
Urbanization Promoting Area in 1999

in 1978 and 1999.

Fig. 12 The Urbanization Promotion Areas in the
Naka/Ayase River Basin in 1978 and 1999

Over the course of the 20

intervening years, urbanization promotion areas
increased in size slightly as the parts marked inyellow were incorporated into urbanization
promotion areas.
This

slide

shows

how

the

urbanization

promotion and urbanization control areas
correspond to the three areas mentioned
previously.

U
Ur rbaba ni zni ati
za on
tio P
r
n
Pr om
om otio t ng
in A
r
g
Ar ea
ea in
in 19719 8
99

The white parts on the diagram on

the left show low lying areas that were
subjected to flood damage mitigation measuresand continued urbanization, meaning that thesewere set out as urbanization promotion areas.

Fig. 13 Low-lying Areas being Corresponding
to Urbanization Promotion Areas

The other areas are urbanization control andadjustment areas, consisting of woodland andfields expected to function as water retaining
areas for the purposes of flood damage
mitigation and paddy fields expected tofunction

as

water

retardingareas.

Development was restricted in these areas topreserve

the

river

basin’s(damage) mitigation capacity.

11

naturalflood

This slide shows urbanized areas in 1985.

Urbanization Promoting Area in 1978
Urbanized Area in 1985

Fig.14 Urbanized Areas (blue, yellow and red) in 1985
with Urbanization Promotion Areas (blue and yellow)

And this slide shows urbanized areas along theriver basin in 2000, 17 years on from theimplementationofcomprehensive

damage mitigation measures.
from

the

diagram

that

flood

It is evident

urbanization

has

progressed not only in the urbanization
Urbanization Promoting Area in 1999 (blue and yellow)
Urbanized Area in 2000 (blue, yellow and red)promotion areas marked in blue and yellow, butalso in urbanization control and adjustment

Fig. 15 Urbanized Areas (blue, yellow and red) in 2000

areas outside of such areas.

with Urbanization Promotion Areas (blue and yellow) in 1999

Despite the fact that developers working inurbanization control and adjustment areas are
obliged to implement rainwater retention andinfiltration measures in line with the scale ofdevelopment,

it is clear that development hasgone above and beyond the original concept
and principle of comprehensive flood damage
mitigation plan.
The reason for this is that restrictions on
development were relaxed from around 1985
onwards due to economic and political factors,
not the least the revitalization of the economy
on the back of private sector activity.
The authorities responsible for flood damage
mitigation actively supported development
during the latter half of the 1980s as plans weredrawn up and initiated for a hugely expensive
metropolitan outer drainage channel in the
midstream area in an effort to supply the areawith quality housing.
principles

withmitigation policy.

12

This was a change inregardtoflood

damageIn spite of developments such as these however,
the extent of urbanization promotion areas
under land-use guidance and regulations set out
for the purposes of flood damage mitigation in
the Naka/Ayase River Basin have remainedlargely unchanged from the initial plans. As
urbanization is encouraged with flood damage
mitigation in mind, the original concept is still
more or less in place and can be said to have300

This slide outlines changes in the levels of

The Start of Flood Damage Mitigation Measures
In 1983
Average total rainfall in the Basin200

flood damage along the Naka/Ayase River

40000

30000

Basin.

20000

of rainfall, the total inundated area and number

10000

of

0

decreased significantly.

30000

20000
100

10000

0

19
58
.9
19
66
.6
19
79
.10
19
81
.10
19
82
.9
19
86
.8
19
91
.9
19
93
.8
19
96
.9
19
98
.9
19
99
.8
20
00
.7

0

Inundated area [ha]Number of inundated houses
Inundated area

Number of inundated houses

Average total rainfall in the Basin[mm/48hr]

proved effective to date.

Whereas floods for the same amountbuildings

experiencing

flooding

have

Although this islargely the result of the implementation of
structuralFig. 16 Changes of Inundated Areas and Houses

measures,comprehensive

flood

damage mitigation measures can be regarded asat Time of Recorded Flooding in the Naka River/Ayase River Basin

having been highly effective in this case.
In

this

next

comprehensive

The Flood Damage
Mitigation Program for the
Eastern Sub-urban Bangkok
Areas (Basin)measuressection,I

flood

damagemitigation

by

Bangkok

implemented

will
the

examineMetropolitan Administration (BMA) in theeastern suburbs of the Bangkok metropolitan
area in Thailand. The Japanese government
provided technical assistance at the planningstages of this project through the Japan
International Cooperation Agency (JICA), an
initiative in which I myself was involved.
Since then, the BMA has continued to make
improvements and alterations in line withchanges in levels of flood damage and social,economic

andpolitical

conditions

andinvestigate and observe measures carried out,
while (whilst) still keeping to the original basic
plan.
The majority of the data that follows is from13

staff at the BMA or staff at the Thai Royal
Irrigation Department (RID), an organization
with which I myself subsequently had chance to
get involved as part of technical cooperationfrom the Japanese government with theformulation of flood damage mitigation plans
for the full length of the ChaoPhraya River.
Most of you will probably already be familiar
with the following section of my presentation,
so I will try to be as concise as possible.
This slide shows the full length of the
ChaoPhraya River.

Fig. 17 The Chao Phraya River Basin

This slide shows the Bangkok metropolitanarea, which is located in the downstream areaof the Chao Phraya River.

Fig.18The Bangkok Metropolis

This slide shows the midstream area of the
Chao Phraya River and the network of rivers
and agricultural channels in the downstream
area of the river.

Despite (some) flooding in

the Bangkok metropolitan area, this network ofchannels discharged large volumes of water

Fig.19 The Rivers
and Irrigation
Canals in the
Chao Phraya
River Basinfrom the north to the Bangkok metropolitanarea, during major flooding in 1983.

14

This slide indicates estimated increases in
population at the time that flood damage
mitigation plans were drawn up for the eastern
suburbs of the Bangkok metropolitan area inthe wake of major flooding in 1983.

In actual

fact, I believe that the population has probably
grown and urbanization progressed at an evenfaster pace in reality.

Fig. 20 An Increase in Population in Bangkok
Metropolitan Areas (predicted at the time of the Program
started)This shows land (ground) subsidence in the
Bangkok metropolitan area, particularly in theeastern suburbs where flood damage mitigation
plans

were

drawn

up.

Although

thissubsidence was caused by the pumping ofunderground water, it became particularly
severe around 1983.

Although the subsidence

has been alleviated to some extent by current
Fig. 21 The Land Subsidence of Bangkok Metropolitan Areasmeasures, it has not been stopped completely.

(left: prediction, right: subsidence from 1933 to 1986)

The scope of subsidence is also growing andchanging.
Subsidence has aggravated the conditions forflood damage.

In areas such as Phra Khanong,where flood damage was most severe in 1983,
it was not possible to drain flood water into the
ChaoPhraya River, resulting in areas remaining
flooded for up to three months and sufferingmajor damage.
This slide shows the network of waterways in
the Bangkok metropolitan area in old timeFig.22 Rivers and Klong(old time)15and this slide at present time.

As is the case in

the Tokyo metropolitan area, the disappearanceof canals and agricultural channels as a result ofadvancingurbanization

has

also

made

conditions worse in terms of flood damage.

Fig.23 The Disappearance of Rivers and Klong(recent time/ blue: rivers and klong, green: roads)

This slide shows the areas that became flooded
during flooding in 1983.

Fig. 24 Inundated Areas for the 1983 Flood

This slide outlines measurements of the volume
of water flowing from the north during flooding
in 1983 taken by myself and a JICA consultant.
Despite the fact that urban areas of Bangkok
were flooded, 80m3 of water per second
Fig.25 The Inflow
Discharge fromthe Northern
Agricultural Areas

continued to flow through from the north.

This is a photograph of the flood in 1983.

Itshows the flood damage in Bangkok at thetime, as a city reliant on vehicles saw its roads
flooded.

The scenes of flood (water) damage

were something new to the city at the time.

Photo 1. The Scene of the 1983 Flooding

16This slide outlines the comprehensive flood
damagemitigation

measures

that

were

implemented. Essentially, the almost same
comprehensive measures were implemented asin the aforementioned case of the Naka/Ayase
River Basin.

Fig. 26 The Comprehensive Flood Damage Mitigation Measures
for the Eastern Sub-urban Bangkok Area (Basin)

This

is

a

simplediagramoutlining

comprehensive

flood

damagemitigation

measures in the eastern suburbs of the Bangkok
metropolitan area.
It shows both structural measures, including
waterway improvement work, the installation ofdrainage pumps, levees (polders) to prevent
Fig. 27 The Conceptual Diagram of the
Flood Damage Mitigation Measures

flooding from rivers and waterways (klong), an

for Eastern Suburban Bangkok Metropolitan Areas

outer embankment called the King’s Dike andflood gates, and non-structural measures,
including the preservation of flood water
retarding capacity in the green belt area on theoutside of the King’s Dike and on the outer sideof the secondary barrier positioned inside theKing’s Dike and the provision of rainwater
retention areas to retain rainwater inside thesecondary barrier.
This slide shows the structural measures.
Plans

were

set

out

in

line

with

the

characteristics of the river basin and included

Fig. 28 Structural
measuresblocking off the flow of flood water fromoutside the area, development work on rivers
and klong to improve flood drainage capacity,
positioning levees (polders) and installing
facilities such as drainage pumps and floodgates along the Chao Phraya River, and so on.

17This slide shows the non-structural measures. It
is an essential part of plans not to increase thepotential flood damage and to keep the naturalfunction for flood damage mitigation.

Plans

included the King’s Dike and the green belt

Fig. 29 Green Belt,
Retarding Area andRetention Area asarea on the outside, flood water retarding areas

Non-Structural
Measuresbetween the King’s Dike and the secondary
barrier and flood water retention areas on theinside of the secondary barrier. These measures
were planned in order to preserve flood water
retention and retarding capacity in line with thecharacteristics of the river basin.
As areas that have always been susceptible toflooding during floods, plans were set out to
restrict and control urbanization in these areas.
There were no land-use plans formulated for
the Bangkok metropolitan area during theplanning stages.

Instead, land-use plans forthe area were drawn up at a later date by the
MinistryofInterior.

Authority

for

the

formulation of land use plans was thentransferred

to

the

Bangkok

Metropolitan

Administration, BMA, after that.
This slide shows the BMA’s current land use
plan.

Fig. 30 The Bangkok Metropolitan Administration’sComprehensive City Plan

18

This slide features an outline diagram of theaforementioned land-use plan set out from thestandpoint

of

flood

damagemitigation,compared to the current land-use plan for the
Bangkok metropolitan area.
Although the land-use plan does not exactly
match the originally envisioned flood damage
mitigation plans, a significant portion of theFig. 31 The Comparison between the Plan for Flood
Damage Mitigation and the Land Use Plan

original

plans

are

still

in

place

today.

Specifically, the green belt area remains inplace in the Bangkok metropolitan area today
as it was initially.
The flood water retarding areas outsidethesecondary barrier have been designated as
low-density land use areas.

The flood water

retention areas inside the secondary barrier
have also been designated as low-density
land-use areas, with flood water retarding
basins as structural measures also being
installed in several places.
As in the case of the Naka/Ayase River Basin,
land use is not determined exclusively from thestandpoint of flood damage mitigation.
Although development has also continued in
the Bangkok metropolitan areas resulting fromsocial, economic, political and other suchfactors, in broad terms the flood damage
mitigation-basedland-useguidanceandregulations are still in place to some extent andwould be fair to say that they have beeneffective to date.
1983

1995

2002

This slide shows the main flood damage in thedownstream area of the Chao Phraya River
Basin since 1983.
Despite some partial flooding, the eastern
suburban

river

basin

in

the

Bangkokmetropolitan area has not flooded since 1983.
Fig.32 The Recent Flooding Areas in the Chao
Phraya River Basin (inundated areas)

Moreover, any partial flooding has been shortterm, lasting a matter of days or hours rather

19than several months, marking an end to the sortof flood damage that occurred in 1983.
Although this is largely the result of theimplementation

of

the

aforementioned

structural measures, it would be fair to say thatthe comprehensive flood damage mitigation
measures have proved effective.
This is a photograph of a retaining wall (leveeor embankment) designed to guard against
flooding from the Chao Phraya River.
Although the risk of flooding from the Chao
Phraya River has been significantly reduced
thanks to the installation of levees such as theseFig. 33 Flood Protection Walls (levees) along the
Chao Phraya River

in most areas, they may have sparked(left: usual days, right: flood season)

controversy with regard to their impact on the
scenic waters around Bangkok.
My conclusion consists of four points, as shown

Conclusionon this slide.

(1) Setting out a fundamental theory and a basic
flood damage mitigation measures .

(1) I have set out a fundamental theory with

(2) The results of comprehensive flood damage
mitigation measures in the eastern suburbs of bothregard to alleviating flood damage and used thisthe Tokyo and Bangkok metropolitan areas.

as the basis upon which to outline a basic flood(3) Comprehensive flood damage mitigation
measures: positive effect in gently-flowing riverdamage mitigation measures .

basins in low-lying areas experiencing rapid urbanization.

(2) I have reported on the results of(4) Non-structural measures: Land use guidance
and regulations being effective as an essential

comprehensive flood damage mitigation

part of flood damage mitigation.

measures implemented in river basins in theeastern suburbs of both the Tokyo and Bangkok
metropolitan areas.
(3) As a result, it has become apparent thatcomprehensive flood damage mitigation
measures have a largely positive effect ingently-flowing river basins in low-lying areas
experiencing rapid urbanization.
(4) I have discussed non-structural measures in
the form of land use guidance and regulations
in particular in detail in my report, as a result of
which it has become apparent that land-use
guidance and regulations (measures to limit
increases in potential damage) are effective to a20

certain extent as an essential part of flood
damage mitigation.
I would emphasize the 4th, on non-structural
measures.
Thank you for your attention.

Thank you for yourattention

Questions and Discussion
Chaired by Junichi Yoshitani, Public Works Research Institute
Chair:

Although the time for questions has been scheduled for after the complete presentation,
specific doubts and opinions can be expressed at this point.

Question:

He does not live in Thailand, but I believe that the project he began in 1982 has always
been on his mind.

Dr. Yoshikawa emphasized that he would like to see acomprehensive and more active approach to the water policy related issues.
he has revisited us quite often and maintained regular contact.

In fact,

However, I believethat the use of the retardation basin has not been effective because of the difficulty inpropagating the idea that storing water can reduce the risk of floods.

It appears that

constructing pumping stations and the like have been more successful.

I am unsureof whether we are comparing the idea proposed here with that proposed for the Ayase
river area.

Has retardation been more successful than pumping in Japan? Further,

how would you convince people that the two technologies are the same and that bothshould be implemented?
Answer:Although this is a slightly difficult question, in truth, the situation in Japan is similar tothat in Thailand.

People are actively concerned with how to mitigate floods soonafter it; however, with time, people tend to forget.

In Japan, the improvement of thedrainage system continues.
In our plan, we had hoped to maintain the natural flood retention and retardation in the21urbanization control and adjustment area, which is on the periphery of the urbanization
promotion area.

The urbanization promotion area was determined in 1983.

After 17

years, in 1999, the urbanization control and adjustment area remains on the peripheryof the urbanization promotion area.

This suggests that our plan is currently still

effective, and perhaps, this is stricter in comparison to other cases.
Question:

I am in favor of a retardation basin.

The Governor of Bangkok recently proposed a

housing project in which each house would be equipped with a water holding facility.
Although this is a good idea, I believe that it is extremely difficult to implement.

Forinstance, estate prices are very high in Bangkok and accommodating a holding pond
will require 30% to 50% of the total land for the project.

Thus, the housing projectwill be unfavorable to the developers and expensive for the consumers.
I believe that Bangkok as a whole should be considered for flood alleviation.

A

King’s dike system similar to the holding pond but much bigger, perhaps 5 to 15
million cubic meters, should be constructed.

This is because a small pond in one

housing project maybe insufficient and difficult to implement.

I fear that the

Bangkok Metropolitan Administration will introduce this concept and reclaim thehousing estate to build holding ponds.

22

3.

Recent Progress in Flood Management in China
Cheng Xiaotao
Director, Professor of China Institute of Water Resources and Hydropower Research
I

will

begin

my

presentation

with

an

introduction of river basin management; then, I
will discuss the current river basin management
institutions, the major issues existing in river
basin management in China, and conclusions.

China is a large country on the east of theEurasian continent.

Topographically, it ishigher in the west and is lower in the east;
consequently, some major rivers flow eastwards
to the sea.

Further, China can be divided into

three steps: the Qinghai-Tibet plateau with anelevation of 4,000 meters or more, the plateau
and basins with an elevation of 1,000 to 2,000
meters, and the vast plains and hills withelevation of 500 meters or lower.
Further, China has a few major rivers, including
the Pearl river in the south, the Yangtze river,the Huaihe river, the Yellow river, the Liaoheriver and the Changjiang river.

There areseveral smaller rivers as well.

A total of

50,000 rivers in China cover an area of 100
square kilometers or more; among them, morethan 1,500 rivers cover an area of 1,000 square
kilometers or more.

The total basin area ofrivers flowing into the sea accounts for
two-thirds of the total Chinese territorial area;
the remaining one-third is the inland river
basin.

23

At

present,

there

are

water

resources

commissions responsible for improving themanagement of the seven major river basins.
The Chang Jiang Water Resources Commission,
the Yellow River Conservancy Commission,
and

the

Huaihe

River

Water

Resources

Commission were established in 1950.

The

Haihe River Water Resources Commission and
the Pearl River Water Resources Commission
were established in 1979.
River

Water

Resources

The Song-Liao
Commission

wasestablished in 1982; the Taihu Basin Authority,
in 1984.
The current river basin management institution.

According to China’s Flood Control Law of1998, flood prevention activities should beconsidered during the overall planning; theexecution

shouldbecombining

river

basin

at

different

levels,managementwithadministrative division management.

24

At present, a system of laws and regulations
concerning flood damage mitigation is in place.
The Water Act, the Water Course Management
Regulation, and the Guidelines for Security andConstruction of Flood Detention Area were
implemented in 1988; the Flood Fighting
Regulation, in 1991; the Flood Control Law, in
1998; and the statute for compensation forflood detention area, in 1999.

Further, in the

recent years, schemes pertaining to significant
activities against the existing floods with regard
to the Yellow, Yangtze, Huaihe, and Yongding
rivers have been authorized.
The process of evolving from flood control toflood management began in the 1980s when
China established reforms and opened its
economy.

Following which, several issues

concerning flood management arose; thus, in
2003, China moved from flood control to flood
management.

A series of countermeasures

such as enhancing the policies and regulations,institutionalizing

andimproving

prevention

drought

reliefandflood
schemes,

initiating specific planning, promoting thedevelopment of the information system for
flood

and

droughtmanagement,

andundertaking research projects, were taken.
The Asian Development Bank supported a
research project that aimed to develop a
strategy for integrated flood management
suitablefortheflooding

characteristics

observed in China and the increasing pressuresencountered

due

to

rapid

urbanization.

Several workshops were organized, including
one on November 25, 2004, for which an
inception report was made available; anotherone was held on April 25 and April 26, 2005,
for which an interim report containing the25current practices in flood management in the
People’s Republic of China and a case study on
the six selected provinces that differ in terms of
their river basins and economic development
zones, was made available.

The third

workshop was held on December 5, 2005, forwhich a draft of the final report was madeavailable.

The final report was published inJune 2006.
China made flood zoning of the whole nation afundamental activity in the 10th Five-Year
National Flood Control Planning (2001–2005).
The 11th Five-Year National Flood Control
Planning will commence this year.

This table shows the figures of zoning.

We divide the zone by seven major rivers.

26

The seven major river basins, especially in thelower reach, are major flood prone areas withan area of 1.06 million square kilometers(11.2% of the total area) and 407 cities within it(61% of the total number of cities).

A

population 840 million (66% of the total
population) resides in the flood prone areas.
The GDP produced from this area is 80%.
Therefore, the flood prone areas are the majorsocio-economic zones in China.
From this map, we can understand which parts
the flood is severe under our standard of flood
prevention.

Originally, we regarded floods as hazardous
and only understood its natural characteristics;
however,wenow

understanditssocialattributes and regard it as having resources andenvironment

features.

understandtheSubsequently,

complicatedwerelationships,

interactions, and transformations among thesefeatures.

Thus, we believe that the damages

caused by floods can be beneficial, andconversely, the benefits can be destructive.

27

Flood management is defined as a collective
noun representing a series of activities that
follow sustainable developmental principles,
aim at creating harmony between man andnature, rationalize flood control activities,
enhance self-resilience capacities, accept therisk involved in utilizing flood water as aresource, and help to improve the water
environment.
Hence, we believe that flood management is an
endeavor to achieve the most favorable
circumstances by effectively improving andoperating all related flood prevention andmitigation

systems

uncertainties.

under

a

seriesofThus, I would like to emphasizethat measures taken to mitigate flood damage
may not necessarily have the best impact on thepotential social, economic, and ecologicalaspects.
Recently, we realized that the impact of floods
on the government’s prestige, social stability,
economicdevelopment,

environmental

protection, and the restoration of the ecosystem,must also be considered.

Considering the risk

involved in improving these aspects needs to be
examined at the technical and strategic level.

28

With regard to the major problems that exist inriver basin management, the flood zone is not
only a flood prone area; it is also an area withthe highest density of population and an area of
rapid economic development.

Although thedevelopment of flood prevention systems in
China has considerably progressed, many issues
pertaining to river basin management still exist
and have not been dealt with.
Incompletion of Flood Control System.

Further, most of the main dikes along the majorrivers have been built gradually over a periodof time; hence, their foundation is weak.

Mostof the dams were built in 1950s and 1960s;
after operating for about 30 to 40 years, major
problems have arisen.

One-third of the 85,000

dams are in poor a condition.

Moreover, activities that increase the risk offlood damage have not been effectively
restricted by the local authorities, and the laws
related to flood management have not been
implemented.

29

The development of a flood prevention system
lacks the stable source and mechanism required
for national investment.

In addition, although the countermeasures toprevent exceeding floods have been authorized
for certain rivers, they are still in a nascentstage.

And for other major rivers, they are still
undefined.

In conclusion, the people of China have lived
and evolved alongside floods from time
immemorial.

The improvement of river basin

management is considerably challenging andrequirespersistence.

DuringChina’sdevelopmental period, it encountered a series ofchallenges when dealing with extreme watercrisis.

30

Presently, new issues on flood management andflood damage mitigation have arisen and willcontinue to do so with the rapid increase inurbanization.

After establishing a sound legal

and managerial system, the improvement of theflood

management

systemtofacilitatesocio-economic development will be the mainarea of focus.

It is imperative that we incorporate experiments
and tests conducted in developed countries into
ourpresent

situationtodevelopacomprehensive and integrated river basin
management system.

Questions and Discussion
Question:

Presently working as scientists, we are looking for effective parameters on which tobuild.

We believe that due to the misuse of land and due to increased operation,

deforestation has risen and its effects have been detrimental.

Looking into the past,

the population and deforestation was less; we believe that changes in the global
climate have had a significant impact on floods.
The Tone river in Japan can be regarded as a fine example of flood damage
mitigation.

According to the policy, people in the city are evacuated to a safer area

to prevent flood damage caused by the Tone riverfront.
are unable to evacuate people to another area.

However, in Bangkok, we

Even though we are aware of thecapacity of water needed and the extent to which the Chao Phraya river and the rivermouth need to be widened, we are unable to do so.

In your country, the decision to

construct a dam is made regardless of the challenges involved.

This is because thepeople are aware of their responsibility towards flood damage mitigation.
In Bangkok, the land belongs to the king.

Regardless, the people have agreed tothe projects approved by the government.

However, many large-scale projects thathave been approved cannot be constructed.

Although we are aware of the existing31

problems, as scientists in Thailand, we are unable to solve them despite several
discussions.
Answer:Even in China we have attempted to implement several measures, particularly after
the 1998 floods.

Although the government has established 32 policies, problems

still exist because of our population and the need for basic resources.
Consequently, we believe that moderation is crucial in flood damage mitigation.

32

4.

Best Practices Found in China’s New FloodManagement
Junichi Yoshitani
Public Works Research Institute of Japan
Dr. Xiaotao and I have been working together
on analyzing the water and flood management
policy in the Changjiang river basin. This slide
shows typical flood control measures. We build
dams and reservoirs across streams and levees
around rivers to control floodwater. We alsobuild retardation basins around rivers orconstruct diversion channels to control floods.
In this presentation, I will focus on retardation
basins.
In yesterday’s issue of The Nation, it wasreported that the king has granted the RID
permission to divert the flood water into his
properties at Pathum Thani and Saraburi.
Such methods are extremely unique to Japan aswell as China and are perhaps possible only in
Thailand.

The Tsurumi river basin is an example of land
use management for flood control in Japan. It is
in a highly urbanized area of Japan with limited
space.

33

In this river basin, the developers have built
small-scale storage facilities that in most oftime serve as tennis courts or playgrounds but
can be used for retention of rainwater during
floods.

This is regulated by the landdevelopment code under the city ordinance.

The tributary of the Tone river that flooded in
1886 can be regarded as another example.
Following the floods, the government revised aplan for flood mitigation under which a
retardation basin was constructed.

In order toconstruct the retardation basin, certain residents
were relocated; moreover, the government andthe landowners signed an agreement that was
not under any law or ordinance and was termed
as an easement.

According to the easement,

the government was required to pay somemoney to the landowners at the time of signing;
however, the government was not responsible
for paying any damages or compensation after
the agreement was signed.
The next is the Changjiang river flood
management case. This slide shows the wholebasin of the Changjiang river and the Three
Gorges Dam.

34

The Chinese Government built huge retarding
basins along the Changjiang River. Now, total
capacity is 50 billion cubic meters.

My topic outline is this.

In this presentation, I will focus on issues
concerning land use management, such as theauthorization of land, ownership of land, andflood

controlsystem(structuralor

non-structural), for constructing retardation
basins, particularly in China.

Dongting

Lake

(one

of

China’slargestretardation basins) has been shrinking with
time.

35

During the 1950s and 1960s, the lake shrunk
drastically as seen in this graph.

It was due to reclamation by the local farmers,
although it was said that the sediment depositedfrom the Changjiang river was a contributing
factor.

The reason why this lake reduced in size stems
from

the

flood

government.

policyoftheChineseAccording to this policy, thelake should have a retention function; however,at the same time, it can be used for agricultural
purposes.

Thus, while such policies may result in an
effective land use, they are not necessarily
consistent with flood control purpose.

Owing

to this policy directive, the Chinese governmentis unable to divert floodwater into retardation
basins because of the 6.8 million people
residing there.

These are important lessons

that have been learned.

36

Following the severe damage caused by theBest practice #1: 32-letter FloodControl Principles

1998 floods in the Changjiang river basin, theChinese①封山植樹：伐採のための入山を禁じ、荒廃地には植樹する。

government

has

commenced

anexcellent recovery and adopted 32-letter flood②退耕還林：急傾斜地の耕地を森林に戻す。

Stop rice-field
return lake
④平垸洪行：（垸）輪中堤を撤去し、洪水を円滑に流す。 Remove⑤以工代賑：納税する代わりに河川工事に従事する。 dike letflood go⑥移民建鎮：移住して新しい町を建設する。
Move people build⑦加固干堤：堤防を強固にする。
⑧疎通河道：川底を浚渫して疎通能をあげる。town③退田還湖：干拓田を湖沼に戻す。

control principles.

分蓄洪区（遊水地）の効率的な利用へ向けた政策
1

Further, the Chinese government enacted the
Flood Control Act in 1998 and began theprocessofremoving

retardation basin.

peoplefromthe

It also proposed theremoval of the ring dikes and the establishmentof related agencies that would implement
specific programs to support and provide relief
to the people residing there.

Moreover, theChinese government has initiated programs tocompensate the people still remaining in theretardation basins, who are affected by thediversion of flood water.
It looks very successful so far, and the Chinese
government is removing huge number of people
from retarding basins.

37

These

are

some

more

detailsabout

accomplishment of these programs.

The Chinese government started flood damage
compensation programs because still somepeople are remaining in the retarding basins,
and this is also a successful practice.

In sum, we at CREST believe that China’s goodpractices can be applied to other countries,
including Japan, because of their uniqueness.
A comparative in-depth study is required forJapan to be able to implement these practices.
For instance, a comparison of the two countries’social conditions such as the authorization ofland, ownership of land, or flood control
systems is necessary to determine whether these
programs can be applied to Japan.

Questions and Discussion
Question:

In Thailand, dikes signify borders, and we have been building one border after
another.

Removing dikes would imply removing the borders, and I am unsure of

how this should be communicated to the public.

In Thailand, we need to conduct a

serious simulation study (maybe even request Dr. Pornsak to build this model) to
remove all borders and witness the quick recession of the floods.
Answer:I believe that this is a very interesting point that should be addressed in thediscussion session.

38

5.

Policy Evaluation of Comprehensive
Control Program in Japan

Flood

Minoru Kuriki
Public Works Research Institute of Japan
CFC (Comprehensive Flood Control) was
evaluated recently, and we will discuss theresults of this evaluation.
Let me first discuss flood control evolution.
Initially, an ad hoc crisis-provoked response
was implemented, in which local variables were
measured.

Since this was inefficient, along-term plan was introduced on a moreriver-basin basis.

A comprehensive approach

was then adopted and an inclusive flood control
strategy was proposed.

River administrators,

city planners, and sewage managers wereinvolved in this.
When implementing CFC in Japan, we had toconsider that the population and assets areconcentrated in the river basins and not in theflood plains.

Rapid urbanization occurred inthis area, making it difficult to retain and holdwater.

Therefore, the volume of flood flow

increased

anddecreased,

increasing

flooding.

39

flood

concentration
theprobability

time
of

CFC

followed

threemeasures.

First:

protective structures for basin improvement andwaterretention

improvement

areas.

Second:basin

measures.

Third:

loss

prevention, publishing previous flood reports.

After 20 years of CFC, the need to evaluate it
was felt.

Policy Evaluation will clarify

administrative measures and then compare theresults of these measures to consider thepeople’s perspective.

Administration shouldbe effective, the measures should focus on
outcomes from the perspectives of people’s
reactions,generatesynergism,

and

be

accountable.
After policy evaluation began, three activities
were emphasized: policy checkup (generalpolicy performance evaluation); policy review(evaluating

specific

themes);andpolicyassessment (prospective policy effects before
implementation).

I

will

discuss

policyreview,whichisundertaken to evaluate the effectiveness ofadministrative measures and analyze causal
relationships.

Objectives and proposed resultsof such measures are evaluated after selecting
30 themes by the ministry, MLIT, CFC ischosen as a theme because of the need toevaluate its effectiveness.

40

Since the Japanese socioeconomic condition
has changed, it is necessary to decide whether
this policy should be continued.

Moreover, anevaluation was necessary to determine whether
further investment or a collaborative approach
was required.

The evaluation was undertaken during 2002 to
2003, and five points highlighted.

First:

whether CFC was required in light of rapid
urbanization and failure of the traditional
approach.

The first aim is reduced inundation damage as
explained by Dr. Yoshikawa, which wasachieved over a longer time.

The initial aim

was, in 10 years, protection when rainfall
intensity is 50 mm/h.

Second, with regard to program scope, 17 small
rivers were chosen for CFC implementation.
Morerivers

could

have

been

included.

Although comprehensive flood forecast andcontrolmeasureswere

implemented,

benefiting areas were lesser.

theUnder CFC,

river basin detention and infiltration were also
initiated.

41

The multifaceted collaboration was examined;
it was considered that a Detention Infiltration
Facility should be installed, and that theplanning was not sufficiently detailed.

Few

infiltration facilities plans were introduced.
Further, although many sewage projects were
undertaken, the influence was greater, andcoordination with river administration was
insufficient.

Finally,flood

mitigation

information was published, such as potential
inundation area maps.

Among the 17 rivers,

maps of only 7 rivers were published.

Further,

only 48 of 180 municipalities published sucharea maps.
The Japanese socioeconomic trend was also
examined, and population and urbanizationpressures were observed to decrease.
wasideal for

CFC

continued

heavy

activities

aggravated.

execution;

rainfall

and

This

however,
economic

Underground

inundation damage occurred, and during heavy
rainfall, water flowed underground, leading tosome deaths; therefore, underground inundation
damage should also be considered.
The evaluation committee proposed a new
future direction for flood control.

River basinmeasures were necessary.

CFC concentrated

on investing on few rivers.

Such investment

or

eased

concentration

can

be

throughadditional measures like involvement andparticipation of locals and water circulation.
Conservation investment was proposed along
different points including environment, water
circulation,andparticipation.

The

collaboration of different administrative fields
was considered necessary.

42The Japanese experienced that CFC was notcompletely successful.

What we succeeded was that we chose a few
river basins that were already pressurized by
rapid

urbanization,

andconcentrated

investment; this aided flood damage mitigation.

The first drawback was in basin management:
the run-off in water regulation was tentativeand not permanent, and therefore imperfect;
land-use

controlwas

executedthroughadministrative guidance, without legal authority
to introduce damage control.

Additionally,collaboration with sewage projects was not
sufficient.

After evaluation, in 2003, we introduced a law
on flood damages for specific urban rivers.
Run-off regulating ponds can be permanently
installed by the river administrator.

For

land-use control, legal force was provided only
in designated areas.

43

The law stipulates collaborative measures byriver managers, sewerage managers, and local
authorities.

Thus, after CFC was introduced in 1980, it took
more than two decades for Japan to establish a
strategy that legally allows administrators tocomprehensively
Importantly,

address

since

flood

this

problems.

approachiscomprehensive, it transcends the engineering
aspect and includes the human perspective.
This complicated the issue, delaying the
introduction of a new law or approach in Japan.
I now conclude my talk.

Questions and Discussion
Question:

I laud your efforts.

In our country, however, we have power hungry authorities.

During a flood, everyone should cooperate and fight it together.

You seem to have

faced the same problem, but have you stabilized the situation?

I think that in Japan,

and we need an establishment that is on par with the authorities.

Do you agree?

We can discuss this later, though.
Chair:In this discussion, I want to bring up two issues.
management.

The other is directing water flow in upstream and downstream

conflict areas.

With regard to land-use regulation or management, Dr. Cheng, youmentioned identifying a flood-safe zone.
Answer:

The first is land-use regulation or

Do you have a strategy for that?

In the flood-risk zone, this work was undertaken by the Ministry of Water Resources.
In China, however, land use is managed by the Ministry of Land and Resources.

It

is now the responsibility of the former body to share relevant information so thatappropriate measures can be implemented.
Chair:

Will the Chinese government successfully implement land-use regulation?

44

Answer:

I cannot answer this because I do not know what the plans of the other ministry are.
Since this map was generated for flood-control planning, flood-risk zones will be
excluded; thus, different standards (including investment) should be considered for
different areas.

Chair:The Japanese government concerned a lot about the impact of the real estate when
we publicize this flood risk map.

In early 1980s when the local office released aflooding map first, Japanese government did not get any negative response from thepublic, or real estate, or any other else.
comprehensive risk map.

Then, we released some more

Again there was no negative impact.

Finally, we

expanded this to the whole nation, so we did little by little.
Question:

While designating an area as a “protected,” were the people informed about theinvestments?

Although it is relatively unknown, Bangkok spent considerable

public money for this.

However, I feel the need to publicize this information

because some unfair transactions might have been conducted by using the publicmoney.

Your maps and examples indicate that when one region is inundated,

another region is saved.
the investments.

Only certain institutes can provide dates to authenticate

The common perception is that money is continually being spentfor some flood damage mitigation, but no one enquires about the money source.
When more capital is needed, there is no justification for it.

Politicians andeconomists make major decisions, albeit without consulting engineers.

Thisshould be rectified.
Chair:You mentioned laws for the removal or easing of conflicts between upstream anddownstream communities.

In the legal system of modern Japan, each river basis isindividually considered.

However, a master plan should be drawn to avoid suchconflicts.

Before implementing the legal system, conflicts were rampant in Japan.

Thus, although there are many negative effects, such a plan can resolve suchconflicts.

In Japan, where river basins were tackled in an organized manner, flood

problems were severe, and CFC was therefore implemented.

It was common

knowledge that the river basins were under threat.
The locals asked the Government for help.

Despite the conflicts, since flood

mitigation was prioritized, CFC was successful.
and sharing information is the key.

Thus, working in collaboration

There is no quick solution to this; such

communications and sharing is imperative for the success of CFC.

Additional

issue of easing conflicts: for example, many people need to be relocated before dam
construction.

Much can be learned from such cases that did not lead to grave

conflicts; in such cases empathizing and dedicated government officials play a45

crucial role.

Thus, this approach might be the key to successful implementation.

With this, we conclude the morning session.

46

6.

Rainfall Estimate Based Satellite Images andConceptual Framework of Its Application for
Flood Landslide Early Warning
Saisunee Bhudthakuncharoen
Professor of Mahanakorn University
My Presentation: Rainfall Estimate Based
Satellite Images and Conceptual Framework of
Its Application for Flood Landslide Early
Warning.

These are the contents.

I will discuss the dramatic increase inlandslides due to floods, which leads to sudden
deaths and damages.

Early warning isimportant to avoid such catastrophes.

This study aims to describe the causes of flood
landslides in Thailand, and then, estimate therainfall using satellite data with the help of acase study of the Pasak river basin in Central
Thailand, followed by the discussion on theconceptual framework of the early warning
system.

47

The causes of flood landslides, factors affecting
earth resistance after heavy and prolonged
rainfall, land use change, and deforestation.
In addition, population growth increases humanvulnerability to these disasters.

In the tropical Pacific Ocean, the ocean andatmospheric circulations are closely linked.
Each reaction quickly changes the others.

Normally, easterly trade winds (the red arrow)push Pacific surface water toward Australia andthe Philippines, creating a warm pool (No.1) at
the basin’s western end, resulting in higher
temperature and increased sea level.

As thewind crosses the ocean, it gets saturated withmoisture, releasing it as heavy rain in
atmospheric convection over the warm pool(No.2).

Thus, normally, this region faces

heavy rainfall.

Meanwhile, at the eastern endof the basin, nutrient-rich cold water rises to thesurface, which is favorable for anchovy that isabundantly found along the Peruvian coast.

48

In the La Nina pattern, trade winds strengthen,shrinking the warm pool and cooling thetropical Pacific waters.
andcolderoff

The climate is driertheAmericacoast.

Atmospheric convection is confined to thewestern end of the basin.
rain over Indonesia.

There is abundant

Cold water rises morestrongly along the west coast of South America,
where anchovy is abundant.
This table presents the historical record ofmajor landslide disasters that occurred in
Thailand.

The first column compares the La

Nina, discovered by CDC of NOAA.

In

certain parts in our country, monsoon lasts from
June to August, and in certain parts, from
November to January.

Many landslide disasters also occurred during
2002 and 2004, which were not La Nina years.

In May 2006, the flood landslide occurred in
Uttradit and Sukothai.

As predicted by

NOAA, the Pacific Ocean temperature isincreasing, and next year will be the El Nino
year, and the rainfall amount will be less.
Since all reservoirs are already full, there is no
reason for concern, unless the El Nino lasts
longer.

49

Eight of the 15 major landslide disasters in
Thailand occurred during El Nino years.

This figure shows major landslide disasterlocations in Thailand during the past three
decades; as we can see, landslides occurred in
the highland areas in the northern part of ourcountry, hilly areas in the eastern part, and thesouthern peninsula.

The monsoon forecast predicted flash floods
and landslides in Uttaradit and Sukothai from
21-23 May this year.

Storm clouds were spotted in South East Asia
and Indian Ocean by a NOAA satellite image
taken on 23 May.

50

Maung District Uttaradit

City of Uttaradit.

Maybe the Japanese tourists got stuck on theroof of the train.

Additional images.

51

Land use varies from forest to banana
plantations in the northern part of our country.
Landslides occur in the banana plantation area.

Deforestation decreases vegetation,

and affects human settlement

Soil erosion after heavy and prolonged rainfall.

52

Shallow landslide.

This is from USGS.

River bank failure due to erosion.

Slope failure.

53

Mudslide.

Additional images.

In urban-rural areas, we try to implement a
more efficient warning system, a public
communication system.

Even a gauge station is in Uttaradit.

54

Theroy and methodology.

Reactive approach is out of trend.

Although landslide disaster mitigation mainly
focuses on rescue operations and rehabilitation,
we should try to adopt the proactive approachrather than the reactive one.

We should prepare ourselves for the disaster byplanning emergency responses, recovery, andrehabilitation.

55

One probable solution is monitoring theatmospheric

flows

and

cloud

movement

causing rain and forecasting areas under risk.
This

also

responding

includestopublicwarningevacuation methods.

education

andonappropriate

Currently, we may not

be able to establish an efficient network formonitoring and forecasting.

Thus, the only

solution is estimating.
We observe the rainfall because it is the major
factor controlling the hydrology and is also theprimary source of floods.

Determining

therainfalllocationandmagnitude is a challenging task.

The present study uses satellite reading togauge rainfall distribution of the rain.

Wemight have faced this problem because therainfall distribution is sparse and data is notavailable for mountainous or remote areas.

56

Geostationary

infraredsatellite technology

detects the increase in infrared radiation fromthenearestsurface.

Thisradiationisconverted to temperature: colder temperatures
are associated with higher altitudes, which isclear from the connection between the cloud
top temperature and the rate.

It can be generally assumed that higher clouds
cause greater precipitation than lower clouds.
This figure shows rainfall intensity fromdifferent cloud top temperatures.

This slide presents a case study on the Pasak
river basin.

The catchment area of the basin is

16,300 sq km; the mean annual rainfall, about
1,100 mm; and average annual run-off, 2,800
million m3 or 5.5 l/s/ sq km.

This basin has the large Pasak reservoir
downstream, which was constructed in 2004
with a live storage of 960 million m3.

57

This study used cloud top temperature dataobtained from the Japanese satellite GMS, andobserved the rainfall in Lomsak, Upper
Phetchabun, and Wichianburi.

This histogram

presents the mean rainfall.

The calibration process by using the power-law
regression

fits

between

the

cloud

top

temperature, (TP, in degree Kelvin) and rainfall
observation, (P in millimeter per three hours)
over the study area during the wet season from1997 to 2000.

In addition, the study aims to determine the lagtime and cloud top temperature integrated fromsatellite images.

The lag time was calculated

as one hour.

In the comparison of the observed andestimated rainfall during the wet season of 2001
to 2002, R2 is used to estimate consistency.

58

The flood landslide early-warning satellite
predicted rainfall.

An early warning system appears to be among
the non-structural measures for mitigating flood
landslide disasters, if it is timely and reliable.
Ineffective warning might have caused the highnumber flood landslide deaths.

For more precise information distribution by
early warning systems, a global early warning
network, particularly on climate change, shouldbe established in addition to national andregional networks.

Early warning equipment

should also be installed in high-risk areas.

This system requires a hazard map depicting
high-risk areas as well as a sophisticated sensor
and model; however, despite this, equipment
predicting such a disaster is very difficult.

59Forecasting can be classified into three groups.
For large basins with an area greater than
10,000 sq km, 12-hour advance flood forecast
warnings can be issued based on the waterlevel.

For intermediate basins with an area of

1,000 to 10,000 sq km, rainfall measurement
both from land networks and remote sensing
data (satellite/radar) should be used to issue awarning 12 hours in advance.

For smallbasins with an area of less than 1,000 sq km,
advance flood warning can be issued only whenrainfall forecast is available.
To predict flood landslides, risky areas shouldbeautomaticallymonitored,

especially

upstream regions that are susceptible to flood
flow.

Rainfall during a storm should also be

tracked over the spatial and temporal scales.
The conventional rain gauge measurement
cannot always be used.

We should ensure that forecasting throughsatellite data for mountainous and remote areas
is more accurate than the conventional method.
This requires preparing timely and affordable
data that is in manageable format, organizing
the data as it grows, and establishing a common
land base across government entities.

60

This is necessary because the tropical Pacific
Ocean and atmospheric circulation are closely
linked.

The rainfall in this conceptual framework issuggested to be estimated on near real timebasis from remote sensing.

To issue flood landslide warnings in a given
area

based

on

a

directcomparisonofquantitative rainfall estimates, we should firstevaluate critical threshold values, without an
online real time forecasting system and throughan extremely simplified alert system that can beused by a non-technical stakeholder.

This

could be used as a supplement case of system
failure.

Based on the low production cost andwide-area applicability, early landslide warning
systems (especially in the small watershed area)
can be provided only when the rainfall forecast
is available.

61

This study concludes that heavy and prolonged
rainfall has been one of the major causes offloods and flood landslide.

Due to the

nonavailability of rain gauge distribution in
mountainous and remote areas, flood landslide
monitoring

using

satellite-based

rainfallestimation is perhaps the only reliable source.
In this research, rainfall was estimated using
satellite data.

The aim was to determine a

simple mechanism that would allow issuing
warning to the people in risk-prone areas about
the onset of a major storm.

Disaster

mitigation

lessons.

teachesseveralIrrespective of the precision of the estimate, it
is hoped that community awareness will
increase through hazard/disaster warning.
I thank the Royal Irrigation Department forproviding rainfall data and characteristic data of
the Pasak River Basin and Pasak Reservoir; therainfall and satellite data were obtained fromthe Thailand Metrological Department.

I amalso grateful for the warm hospitality extended
at this symposium by the Thai Hydrologist
Assembly and CREST.

Questions and Discussion
Chairperson: Mr. Subin Pinkayan, Vice president of Thai Hydrologist Assembly
Question:

The new group has developed a new technology.

To my knowledge, thus

far, we have been using radar systems in Bangkok.

If you want to control

the flood situation, you must approach the meteorological and irrigation
departments and health-support officials, because your statements could be
misinterpreted and your actions could either result in cooperation or panic.
I am slightly ignorant about this new cloud temperature technology, but I
believe it has already been standardized for commercial use.

We havecommunicated this to the meteorological department, but your techniquecould also be highlighted.

62

Answer:

Radar is a promising technique for monitoring and early warning.

Question:

How different is your method?

Answer :Using radar data, forecasts can be made three hours in advance sufficient fora warning system.

Unlike satellites, however, radar cannot predict rainfall

in real time. The scarcity of data poses the problem.
Question:

Could satellite data actually dissuade funding agencies?

Is it possible thatthey might be made to believe that satellites are more efficient, leading themto withdraw funding for regulatory or radar rainfall systems?

Could theworkability of your satellite data create hindrances for the installation oftelemetry systems?
Consider landslides for instance.

Satellites, which provide predictions atperiods of three hours or more, cannot predict landslides, which can bepredicted only with more short-term monitoring.

Such monitoring can only

be done by telemetry systems or radar, the installation of which, in addition
to satellite data study, should be advocated to funding agencies or the peoplein Thailand.
Answer:

The GMS satellite data has been used only for academic research.

In mysubsequent research, I shall use NASA satellite data.
Question:

Although satellite images first alert disaster prevention units, their current
application to actual situations is inadequate, merely because satellite data
provides predictions around four hours in advance: events in a shorter period
might not be accurately predicted.

Moreover, these images give only acomparative value of expected rainfall and might not be adequate forwarning systems.
regions.

Initially, we could only use these images for specificNow, the telemetry system might become obsolete.

However,

TMD’s plan to construct telemetry systems in villages to verify or recalibrateradar data with satellite data will in fact increase the accuracy of rainfall
forecasts.
Answer:Rain tracking during storm events on spatial and temporal scales is indeed
quite difficult; overlooking rain tracks, however, might mislead us.

63

64

7.

Flooding Situation & Mitigation Measures inThailandSiriphong Hangsapruek
Director General of Department of Water Resources
In Thailand, the monsoon winds that cause
flooding mostly come from the South China
Sea between July and December, along withmonsoon winds from the Andaman in October.

The monthly rainfall was very low in April andincreased in October and November for the past
30 years.

In the south, the average annual figure is 1,570
mm.

65

Thailand is divided into 25 river basins, which
are subdivided into eight groups.

The largest

is the Chao Phraya river basin.

Floodmanagement is extremely difficult in thesebasins that range from the north and central
plains to the Gulf of Thailand, covering
157,000 sq km.

The second biggest group

covers the northeastern part of Thailand andcomprises three river basins, covering 110,000
sq km.
Satellite images identify the flood risk areas
along these basins.
Phraya,lower

The river basins of Chao

Yom

and

Nan,

and

the

confluence of Chi and Mun are high-risk areasin that order.

Other areas are the Khong andUpper Ping river basins.

The same data can be used to identify otherpotential risk of future flooding, inundated
areas in a 30-day period.

Finally, we have a risk map that shows Chao
Phraya, Nan, and Mekong river basins as
high-risk areas.

Based on the estimate of thedamage shown by the satellite images and theeconomic damages in these areas: we estimate
the annual average of flooding losses at about$US 1,000 m or about 39,000 m Baht, and an
average annual death rate of 148.

66

Therefore, addressing certain policy issues is
crucial.

The Department of Water Resources

is responsible for preparing this policy.

We

discussed this with the Deputy Prime Ministerand the Deputy Minister at the Ministry ofAgriculture and Ministry of Natural Resources
and Environment in the new government.

It ismost important to establish a national policythat covers flood mitigation, particularly in thehighly economic areas.

We hope that the new

government will cover this in the policy;
without their political support, it will be very
difficult to drive the government agencies towork together for this task.
Second, the organizational aspect is also
important.

The

current

Resources

committee

National

Water

not

functionmay

efficiently, and we might need to determine
ways of strengthening or restructuring it as acentral body to assist various government
agencies and local organizations to work
together.
Third, we should draw a flood mitigation planwith well-defined objectives.

We also need toknow the amount of excess water in each river
basin as well as prepare a mitigation program
before, during, and after the crisis.
Many aspects need to be considered to ensurethat the National Water Resource committee
functions more efficiently.

This discussion

involves the concerned ministers and members
from many organizations.

In Thailand, about

10 organizations prefer to work in this field.
Many organizations attempt to be included in
the Department of Water Resources, but theRoyal Irrigation Department is still under the
Ministry of Agriculture.

A similar situation

existed

the

in

Japan

in

Construction and Agriculture.

67

MinistriesofAfter many

issues were raised, we were finally accepted in
the Thai society.
Another important
perspective

is

area

local

from thefutureorganization.

Weestablished river basin committees to manage
25

river

committees

basins.

These

100,000-strong

comprisemembersfromtheprovincial, district, and sub-district levels.
Using these members in water management is achallenging task.
Updating land use maps is an important
technical

issue.

Without

this,

flood

forecasting and mitigation is difficult; a control
map of the repeatedly damaged area revealed
that the present data is outdated.

Since

contour maps are required for hydraulicgeneration, we need to invest more in this area.
We do not have a map that covers the Chao
Phraya river basin; we should be able to predictthe hydrological behavior in the river basins byusing other methods.
We also considered that monitoring the flow ismore important than forecasting.

If we cantrace the path of the rainwater, it will be simpler
to mitigate this water.

It is imperative toprepare a log of the recurring flooding periods
for the city and rural areas, because this will
also help in comparing various mitigation
measures.

68For example, in the flood risk map of the hilly
area, we identified various critical areas in
about

2,300

villagesandrainfall-measuring equipment.

installed

As a result, we

could alert people about the water level before
flooding in four regions.

We have established

400 sites for this system, particularly in thenorthern part; however, many more need to beestablished.
These are some of the satellite images showing
the flood areas in 1995 and 2002.

The operation rules of major resources should
be reviewed at a higher level.

I am sure thateach time this issue is raised, it will be opposedby someone who will incur a loss of revenue
compared with previous figures.

Further, therules established 40 years ago may not beapplicable today because the land use isdifferent.

These issues will need to be raised

during policy discussions with government
agencies, which have different interests.

This

year, the rainfall began in early August, butsince it was not heavy, few paid attention.
The path of this rainwater and the water level
before flooding is not monitored; similarly,
water diversion plans for public wetlands andunused or agricultural areas need to be preparedand relief operations, if required, need to beplanned.

This year this was thought of only

after flooding occurred-something that could
have easily been avoided with due care.
Networking

69

with

established

river

basin

members for reporting the water situation is
also crucial.

Because of limited governmental

budgets and personnel, we need the inputs fromlocal communities that receive more than 30%of the national budget.
Some examples of major reservoirs in the
country: a lot of water is retained at the
beginning of the wet season.

If this water is

let down, damages might be lesser.

We have more than 100,000 wetland areas in
the country now.

These

are

the

organizations

network

government and local communities.

70ofHowever, with the government on one side andthe local community on the other, flood relief
and appropriate evacuations measures are notwell planned.

For example, Phuket Island

adopted a well-planned flood mitigation andrelief strategy only after it was hit by thetsunami; however, during the floods, people did
not take it seriously.

Further, provision ofclean drinking water, food, sanitation, medicalcare, and waste removal also need to beplanned and executed by considering theenvironment of the people living in the affected
area.
These are some pictures of the provision of themobile clean water.

After a crisis, water draining and recovering
shallow wells and ground water holes should be
carried out.

Further, water supply facilities

should be rehabilitated and contamination
should be tackled.

71

As you can see here, the width of water
increased much more by the crisis.

So weshould make it well drained to help the people.

For policy issues regarding medium- andlong-term watershed management plans, notonly each city but also the entire river basinfrom the northern region should be considered
and watershed management measures should be
implemented.
measuresforResearch and development
thedevelopment

andimplementation of such a support system aswell as monitoring and warning systems need
to be undertaken on a larger scale.

Finally,

cooperation with the neighboring nations in theregion for regional flood forecasting should bepromoted.

72

8.

The Current Situation (Oct. 2006) on FloodManagement in Chao Phraya River
Suwit Thanopanuwat
Professional Engineer for Planning of Royal Irrigation Department
Following the 1995 floods, a comprehensive
flood mitigation program was implemented byrequest of JICA, Japan; however, we are again
facing another big flood.

I will summarize theflood management situation in the Chao Phraya
river basin from 1995 to 2006 but first I will
briefly introduce the Chao Phraya river basin.
The flood plains in the country run along theupper section of the river to the delta area in thelower section.
The Chao Phraya flood plains play a criticalrole in the growth of the country since they are
the source of the most productive farmlands.

According to the 1995 statistic, the catchmentsarea of the river is 160,000 sq km withirrigation and an annual rainfall of above 1,100
mm facilitates the irrigation of about 3,600
million m3.

On 12th October, the water flow

was 5,300 m3/s; it has been rising since then.
Since the river capacity ranges from 1,500 to
4,000 m3/s, it is clear that our river capacity issmaller than the downpour, and thus, theoccurrence of floods is unavoidable.

73

The

population

in

this

river

basin

is

approximately 23.020 m, and the GDP of thebasin is about 58% of the country.

Inside thebasin, the GDP from the delta area is 78% of
the basin, clearly indicating that importanteconomic activities are undertaken in the flood
plains, which are financially viable, productive,
and populated.
This chart demonstrated that how high valuesof the properties or economic are in the delta
area.

There

is

highlyeconomic,

andhighlyflood

mitigation,

populated.

With

regardtoacomprehensive and integrated approach has
beenfavoredbysome.

AccordingtoProfessor Yoshikawa’s study, we lag behind inencouraging such an approach and in ourcapacity to deal with it.

Professor Yoshikawa

also mentioned that recent flood mitigationplans were drawn and implemented by in-housegovernment engineers with the help of theconsulting units; however, they shared a lack ofinterest in academia and the academia has no74

receptiveness in this area of study.

As a result,in countries prone to floods like Thailand,
Japan, and USA, research on practical flood
mitigation has not been conducted.

I work asa water engineer in the planning division.

Iagree that the focus is on the basin, but we aretrying to work on this.
This area was inundated in 1995.

We observed changes in land use and loss of
wetlands and flood retention areas.

Moreover,the basin witnessed deforestation and landscapemodification during the last century.

The resulting damages are increasing; in 1995,
the estimated damages were as high as 72
billion Baht.

This estimate did not include

damages such as loss in business and internal
policy.

In this study, an attempt was made toestimatethestatistics.

However, I think that no nation candamageinclusive

of

these

afford to report such high levels of damage.

75

On evaluating the existing projects, we found
that

flood

mitigation

reduced damages.

projects

effectively

The newly constructed

Pasak dam also plays a very significant role.
Undoubtedly, most of Bangkok is safe fromfloods due to a planned drainage system.
However, many urban areas along the river
were severely damaged due to poor protection.
This figure shows the river capacity along Chao
Phraya river and its tributaries, which is an
important aspect of floods in the lower region.
A river that moves downstream is in less dangerof overflowing, but this is not the case with the
Chao Phraya.

This is one of the challenges

that we face and will consider when we attempt
flood management in this flood plain.
Based on the 1995 study, I have proposed two
categories of countermeasures: structural andnon-structural.

Structural measures cover river improvements.
River capacities are different in each location.
We have dikes for future river stability.

The

flood plain of the Chao Phraya is famous forpaddy fields, which are of the basin irrigation
type.

However, there is no canal network to

distribute water to this crop.

The drainage

system in flood plains should be improved.
Further, despite many measures, the capacity of
the river in the rural areas is still insufficient forcontaining the remaining water.

From theperspective of hydraulics, it is still essential toprovide more outlets for excess water, namely,76

flood diversion channels.
Non-structural measures such as reservoir
modification, operational rules, strengthening
the control of flood plains for land use andgroundwater
aspects,areconsidered.

watershed

Financialmanagement,

andcooperation with institutions and organizations
are also considered.

Although specific measures are formulated, thelarger issues are the preservation of the basin
and flood mitigation in the flood plains of the
Chao Phraya.

We believe that if we are able tomanage the distribution of water and water
storage in this field, minimum flood damage
can be ensured.

In order to achieve this, oneof the measures we took was to build a capacity
infrastructure to distribute water from highwater level areas to the low water level ones.
Bangkok and other urban areas are categorized
as high priority areas during flood relief andmitigation, however, agriculture, strengthening
the safer areas, and institution management are
equally important.
In 1995, the municipalities along the rivers
were mostly flooded, except Bangkok, which
was saved due to the precautions taken.
Similarly, we constructed a border around thosemunicipal areas along rivers.

This was carriedout by the Public Works Department and amajor part of the work has been completed.
In Bangkok, a floodwall along the river has
already been built; the wall is sufficiently highto avoid water from overflowing.

However,protecting the Angthong province is prioritized.
Therefore, greater protection of the province
will adversely increase the flow to Bangkok

77and reduce the safety level.

This aspect was

being studied and some alternatives were
proposed, such as further heightening the
Bangkok floodwall.

The BMA officials

opposed this saying that increasing the heightmight not be aesthetically appealing.

The

second alternative is to construct a diversion
channel to maintain or control the downstream
flow at the diversion point.
Finally, after sufficient discussions among
several agencies including RID, BMA, and key
project initiation offices and studying the 1995
flood reports, the diversion channel waschosen.
The maximum discharge was roughly estimatedat 4,500 m3/s.

Our target is discharge at thescale of 1,900 m3/s

We can implement the non-structural measuresby modifying the reservoir operation andachieve about 250 m3/s

78

Most of the reduction work can be undertakenusing structural measures.

The construction of

the new reservoirs upstream can release 500m3/s; flood plain reservation would be about
200 m3/s; improved drainage from the flood
plain to the downstream area and out into thesea can be expected to be above 150 m3/s.
River improvement cannot be ignored due to a
new flood diversion for adding capacity of 800
m3/s to meet the 1,900 m3/s target.
The cost estimate of our measures was 40,000
million Baht, with the highest in the flood
diversion channel.

From 1995 to 2006 some measures have been
implemented, such as flood monitoring andforecasting modeling by RID using the flood
works model, modification of dam operation
rule,

and

telemeteringsystem.

The

construction of dikes, polders, and upstream
storage channels is underway.

However, somemeasures are not undertaken seriously, such as
restoration of cabin areas, drainage systemtreatment, and flood diversion channel.
I will summarize the present situation in theflooding season.

The discharge from Nakhon

Sawan is as high as 5,500 m3/s today, as
compared to 4,820 m3/s in 1995; we are facedwith the chances of a major flood.

Most of theflood plains in lower northern and central
regions are inundated.
villagesaroundThe dike-breachedmunicipality

agricultural areas are damaged.

79

areas

and

The protectedarea of Bangkok is still safe.

The discharge at

Bangsai is 3,900 m3/s but this morning, thewater level is already 4,000 m3/s.
This is just to show that the water is increasing.

All of the reservoirs are already full.

This illustration shows how we try to upgrade
Pasak dam for flood control.

The water level

this dam will be kept low until the end of
September.

At the beginning of the wet

season, we release water to accommodate
excess rainwater; since this is a heavy rainfall
year, the reservoir is already full.

80

The Director General of RID has proposed
ideas with regard to our measures to enhance
our capacity in dealing with or managing
floods.

This is evident from the results of thecomprehensive JICA study.

One of them isthe construction of upstream reservoir that is
Kaen Sua Ten, a controversial issue.

Land use

control for preserving retention areas occurs at
a scale of 1 to 2 million.

It is common

knowledge that in flood plains, water always
collects in the most low-lying areas.

With

regard to compensation methods, we should
consider a cropping method for rice cultivation
to clear the field before it is used for water
retention.

At present, this suggestion is being

opposed since the fields are almost ready for
harvesting.
We also share the general events in this field as
publicized by the media.

Following by His

Majesty King Rama providing more of his land,
RID suggested to construct upstream reservoirs.
Two days ago, the government acted on the“Flood mitigation master plan.”

As per a local newspaper, the Deputy Prime
Minister

Kosit

calledNESDB,MONRE,MOAC (RID), and Research Institute Office,emphasizing the need to cover three key issues
within six months.

First: developing acoordinated work plan for implementing over
five to ten years.

Second: to establish acertification institution.
National

Water

Third: form theManagement

Organization

responsible for investment and policy related
issues.

81

I recently took this aerial image to show thewater drainage problems and water logging in
the fields.

We can see rainwater in the fields

and a high water level in the river, both shownin different colors.
urgently

improve

Therefore, we mustthedrainagesystem.

Highways and houses are located along theriver.
The houses are conveniently located along theriver and the paddy fields are behind thehouses.

Flood embankments or dikes should

be constructed behind the houses, confining thehouses and river between the dikes and saving
the paddy fields.

Our case differs from that of

the Chinese, and we have to think of anothersolution for the problem.
This is another picture.

This is too.

82

I am also a member of the Thai ICID.

I havefound that a special issue of the ICID journal
focused on integrated flood management.
This is what I found.

We might also consider

some of the suggestions in this issue.

One very difficult aspect we commonly
identified was the division of responsibilities
among institutions.

It is often unclear as towho is responsible for which part of flood
management or flood mitigation and/or relief.
Continuing with this chaos might result in aseries of problems or even disasters.

I nowturn to a paper by Professor Shultz.
There is a concern about the rapid growth ofmega cities in flood prone areas.

During thepast decades, mega cities like Bangkok, Osaka,
Shanghai, and Wuhan, have recorded an
explosion in population growth and havetransformed into major and highly populated
cities.

The increase in the value of property inthese cities has been more rapid than the
population growth.

This indicates that it isvery important to carefully invest in the flood
protection scheme.

While coping with thepace of growth of these cities, reclamation has
often ignored in the neighborhood low lying
lands.
When cities expand, they will occupy the
low-lying areas.

From the perspective of ahydraulic engineer, this translates into a
reduction in water storage areas and an increasein urban drainage discharge.

83This is a picture of paddy fields near Bangkok
that we can store water.

But the land across the paddy fields is occupied
by a community.

The new airport in Bangkok was previously awaterretention

area,

which

has

been

completely modified as a solely urban area.

I believe that we should seriously invest inflood mitigation and protection.

A change isurgently needed, especially in light of pastexperiences with similar disasters.

84

The change must be appropriate and necessary,or else political decisions, which do notcontribute to long-term sustainability, may
result.

This is the kind of long-term flood

mitigation and relief plan that we have toprepare, and we now have the information,
alternatives, and solution readily available.
We should hopefully be able to put thought into
action at the earliest.
Following the 1995 floods, we realize that the
Chao Phraya river basin is playing a crucialrole as a catalyst for change.

Our capacity inflood management needs to be enhanced
structurally and non-structurally.

The existing

infrastructure seems to be far below the
optimum protection level.

We expect thismatter to be given due consideration for
appropriate and early corrective action.

The

Director General made an attempt to determine
ways to divert water into the fields, but we need
an official to find such areas.

From theministry’s perspective, it appears that we need
the model of a flood plain that can help us use
the flood plain effectively.
In conclusion, floods will continue to occur,and the people and property in the flood plains
will be at risk.

The situation will not improve

because the cost of a physical solution isunaffordable.

Consequently, although it ischallenging,aneffective

flood

plain

management needs to be implemented and an
integrated flood management program needs tobe prepared.

85

86

9.

Bangkok Drainage and Flood Control System
Teeradej Tangpraprutgul
Former Director of Drainage and Sewerage Department
I will address flood management in and around
Bangkok.

I will also address the cause offlood and assess drainage system facilities forflood protection.

Some people, many years ago…

They used to live in a boathouse.

87But happy, they are not going back to Chao
Phraya river.

Things have been changed very rapidly; wehave many high-rise buildings now.

Regarding the effects of floods in Bangkok, thetwo largest and most important dams are theBhumibol and the Sirikit dams.

The water

storage capacity of these two dams and the
Pasak dam are closely monitored with regard to
the water from the Chao Phraya river.

The

Chao Phraya and the Rama VI dams together
amount to the total water that the RID is
responsible for.
At the end of August this year, the water fromthese two dams was only 400 m3/s.
this is gradually increasing.

However,

At present, waterfrom these two dams amounts to approximately
5,500 m3/s.

On October 11, the water level

was approximately 2.12 meters-the highest; thismorning, the water level was above 1.97
meters.

Based on these figures, it is evident

that a good flood protection system is essential
in Bangkok.

88

The city of Bangkok is approximately 25 to 56
kilometers from the Gulf of Thailand; theaverage land level is about 1.5 meters above
mean sea level.

It was established that the average maximum
inflow passed through Bangkok should notexceed 2,500 m3/s.

At present, the water

passed through the Chao Phraya and Rama VI
dams is 4,500 m3/s.

Normally, the city of Bangkok is a flat land andvery good for agriculture.

But we had a big flood in 1942.

89

In 1983, *** area in Bangkok was a very
popular housing site; however, at the time, thewater supply was not adequate.

Consequently,

groundwater was extracted, resulting in severe
land subsidence; hence, this area witnesses
flooding for more than 2 months every year.

In 1995, the water flow from the Chao Phraya
and Rama VI dams was above 4,500 m3/s.
Following this flood, the BMA considered
constructing a road along the Chao Phraya
river.

Consequently, the RID constructed aroad away from the river; it also served as aflood barrier.

Flood damage in many areas.

The tropical rain in this area essentially causes
the floods in Bangkok.

For instance, heavy

rain causes the water from the Chao Phraya
river basin to overflow leading to floods in thatarea.

Further, there is significant inflow fromthe surrounding area, especially in the easternpart of Bangkok.

Many years ago, this partused to be an agricultural area, and the people
living here had grown accustomed to the floods.
However, at present, people living in this area
are voicing their dissatisfaction.

Further, 80

kilometers of the coastline is also affected by90

the tides, particularly from the end of
September to December.
Besides natural causes, man-made causes,
misuse of land, low efficiency of drainage
systems, and land subsidence (although this has
beensignificantly

reduced)areequally

responsible for floods.
This is the way of rain.

The rain comes fromSouth China Sea when the low pressure is past
after 23 October.

Normally, it will passthrough southern part of Thailand.

Overflow from the river.

Just see the picture.

91

Tidal effect.

There are tall buildings in this area.

Urbanization has also affected the floods in
Bangkok; although the number of registeredpeople living in Bangkok is approximately 5 to
6 million, the actual number is perhaps 10
million.

Formerly, Thailand had many canals that
effectively functioned as a drainage system.
At present, however, as a result of the rise insquatters who live along the canal, theefficiency of the drainage system has also
reduced.

92

Each city should have storage.

This was a flood-prone area many years ago.

Ground water extracting is not allowed now.

Given the above, let us address the steps thathave been taken towards the mitigation offloods.

A total of 2,000 pumping stations

have been installed in Bangkok, with 110 large
pumping stations along the Chao Phraya river.
Having adequate pumping stations is crucial
because gravity does not facilitate water flow in
low lying areas.

Moreover, the environment

was also considered in the planning flood
mitigation.

For

instance,

incolderenvironments, we have constructed dikes toprevent the water from flowing into the city.
Further, the efficiency of the canals has been93

improved by constructing retaining walls.
These are the structural measures taken forflood mitigation.
Non-structural measures include improving thecapacity

of

the

water

retentionarea.

According to the King’s suggestion, a basinwith a capacity of 12 million cubic meters has
been constructed as a retention area.

In

addition, a system of controlling land use has
also been introduced; further, a flood map has
been made available to inform people of thefrequency and intensity of floods.

Moreover,people living in low lying areas have been
informed of using flood-proof material in theirhouses.

Typically, these areas will be flooded

once in 5 or 10 years.

At present, Dr. Pornsak

is responsible for flood forecast and warningfor our department.
Since we have our own radar, we are able toforecast the time and direction of rain; further,
we are able to determine the intensity and thetime the rain will take to travel from one point
to another.

For instance, if we monitor therain in Nakhon Pathom, the time interval before
the rain reaches Bangkok is approximately 2hours; hence, we can issue a warning to thepeople to avoid the flood prone areas.
Polder system.

94

In Bangkok, flood mitigation is conducted infour zones.

The first zone is along the Chao

Phraya river as well as the Bangkok Noi andMaha Sawat canals.

Earlier, the Chao Phraya

river used to be a slow-flowing river; however,at present, the river current is extremely fast.
Consequently, RID have constructed Lad Pho
gate that allow only the floodwater to passthrough and are impervious to saline water.
The second zone in Bangkok is the city areathat is home to the wealthier citizens.

The

King’s dike as well as the greenbelt, which
passes through to the Gulf of Thailand, ispresent in this area.
airportwasMoreover, since theconstructed,

two

big canals

connected to Gulf of Thailand have also been
built.

Since this area requires significant

protection against floods, many retention basins
and tunnels have been constructed.

Since thepeople living upstream as well as those in
Bangkok are farmers, at times, we cooperatewith the AIT and allow the water to flow
through.

In certain areas, water is allowed toenter the catchments in the Bang Pakong river
basin.
Another zone is Thonburi Sai that used to have
many canals, including the Mahasawat canal.
In cooperation with RID, we attempted toconstruct

a

large

pumping

stationhere.

Previously, this area was referred to as the
Venice of the east; at present, many canals still
exist and people continue to use boats astransportation.

95

In this picture, you can see that the retaining
wall, which is 80% complete, will perhaps becompleted next year.

Prior to the constructionof the retaining wall, sandbags were used toprotect against floods.

In the northern part of

Bangkok, many pumping stations have been
installed on both sides of the Chao Phraya river.
Often, people ask why the water is not pumped
out during high tide.

The answer is simple; ifyou pump out the water into the Chao Phraya
River during the high tide, the neighboring
country and its people will be inconvenienced.
As a result, we use a tilo to determine thevolume of water pumped out during low andhigh tides.
The tidal dike.

Flood protection in the city core area.

96

The retention basin published in the paper.

The construction of tunnel: we have proposed
many constructions.

This is the eastern part of Bangkok.

With regard to flood mitigation, a flood control
center that operates 24 hours a day has been
established.

97

A flood control system has been implemented.

We have a monitoring station as well.

That is it for my presentation.

9810. Flood Situations for the next 30 days of Lower
Chao Phraya River Basin
Pornsak Suppataratarn
ASDECON Corporation
In 1983, the lower Chao Phraya region and its
limits were flooded; consequently, we pumped
out water during high tide.

However, as aresult, certain areas were flooded for up to threemonths.

In 1995, again this area was flooded

with water flowing from the north.

In 2002,

similar floods occurred; however, the 2002
floods were at a smaller scale owing to thevarious measures taken for flood protection.
Further, following the 2002 floods, several
dikes

were

constructed

along

the

river;

consequently, most of the area is now safe andonly a few low lying areas are affected by thefloods.
This is the water level along the river at thetime of the major floods during the last 30
years.

As is evident, several changes in thewater level with regard to the direction havebeen observed.

In the lower region, in a large

area of Bangkok and Bangsai, Pakret, the waterlevel increased from 50 to 60 centimeters.
This is my forecast for the year 2006.
This is the rain in the upper basin of the Chao
Phraya dam.

At the time, Dr. Sutat forecasted

that the volume of water in the Chao Phraya
dam would rise to more than 4,000 cubic
meters, but nobody believed him.

However,

as is evident, Dr. Sutat’s forecast was correct.

99

If you notice the pattern of the rain, you can seethat at the end of last month the total rain wasalmost equivalent to the rain in 1995 in theupper region and was delayed by a week.

Consequently, with the high tide and storm
winds gathering, it is predicted that it will rain
for a long period of time and result in anotherflood.

It occurs even though it is not really highintensity.

With regard to the lower region, it had alreadybegun flooding in October.

100

This is the flood situation; Nakhorn Sawan isthe blue colored area.

Further, on comparing the water level of thismonth with that of the same month in 1995, it
was evident that the water level this month was
higher.

I believe that this is due to confiningor some other effect.

I will now discuss the forecast model that I had
developed when I was working at AIT under
the supervision of Dr. Sutat.

Based on the model, we need to further develop
on the Chao Phraya and Rama VI dams.
Moreover, we need to further improve theforecasting system and develop the topographyof area.

101

Subsequently, we should also be able to predict
the water level of the Chao Phraya dam.

This is the dike alignment.

The structural system can be responded and canbe operated for better effects.

This is cutoff channel, which is now operating.

102

The other thing we need to do is to monitor
Chao Phraya dam.

The blue one is this year.

In the first part, the water level is much lower
than 1995.

I think this is due to the relocation.

The water level goes up to almost same level as
1995, but it is about two weeks late compare to
the 1995 flood.

The volume of water passing through the lower
Chao Phraya dam is forecasted to be 3,800
cubic meters.

With regard to the tide, I haveused the tidal pattern of the last two months toforecast the tidal behavior for the next month.

With regard to the tide, I have used the tidal
pattern of the last two months to forecast the
tidal behavior for the next month.

103

This is water forecasting.

We need forecasting using these data.

The results predicted by the model wereconsiderably accurate.

It was found that the discharge was similar to
the Chao Phraya dam.

104

At Ayuthaya, the water level was slightly lower.
However, Ayuthaya will reach its peak in thenext 10 days and the water level will rise by 20
to 37 centimeters and it lasts for 2 or 3 days.

Bangsai: this is the reference point for Bangkok
that is used to check the degree of damage
incurredbythecity-thedischarge

computed based on the water level.

was
At itspeak, the water level will rise by 40 centimeters
during high tide.

It is forecasted that thesituation will be severe for at least a month;
however, I could be wrong.
The discharge in Bangsai area is 3,500.

Memorial Bridge is a reference point to
Bangkok.
This year there will be a series of high tides
because the water that overflowed into the flat
plain area in the west bank will be lesser.

105

It will cause a small high tide in the flat plainarea also.

Unfortunately, however, thisinformation was not available to me at the timeof developing this model.

Situation in the lower part Bang Bua Thong.

Bangya: more populated area and this is amonitoring point.

Samwa: reservoir in the east. It is more
controllable in this area.

106

I believe that the flood map of 1995 will be
extremely useful in forecasting floods for thisarea, although I believe that this year thesituation in and around Bangkok is more
controllable.

The peak appears like this: on 15 at Singburi,on 16 at Angthong, on 21 at Ayuthaya, and on
26 at Bangsai

The peak moving out to the lower part: on 29 at
Pakret, and on 8 November at the Memorial
Bridge.
We should cut the peak and not the basebecause if we cut the base it will be moredetrimental.

107

108

11. Questions and Discussion
Chairperson: Mr. Subin Pinkayan, Vice president of Thai Hydrologist Assembly1

I agree with the speakers who addressed us in the morning session and with the issue of land
subsidence that was discussed in the afternoon session.

Heavy groundwater pumping has

caused land subsidence in many cities such as Tokyo, Osaka, Mexico City, Shanghai, and
Bangkok.

In Bangkok, land subsidence has been considerably controlled particularly incentral area where groundwater pumping is prohibited, however, in the outskirts of Bangkok
and its adjacent provinces, heavy groundwater pumping is prevalent.

I would like to draw

your attention as well as that of the Thai authorities, such as the BMA and RID, to the fact thatland subsidence is a major cause for severe flooding.

Thus, mitigation policies should be

implemented with this fact in mind.
2

I agree with you in that land subsidence is an important factor that affects flooding.

In

Bangkok, despite the fact that land subsidence is under control and its rate is gradually
reducing, the land has subsided by 1 meter over the last two decades.

Previously, the land

would subside at the rate of 10 centimeters a year; however, at present, owing to the effective
measures taken, the rate has reduced to 2 or 3 centimeters a year.

Regardless of this, I willattempt to amend the mitigation measures under the current policy by recommending that thecontrol of land use and groundwater be added to it.
3With regard to the Kaeng Sua Ten project, has its progress been affected by the floods thisyear?

Further, regarding the canal across the Chao Phraya river, have the floods affected its

functioning?
4

At the RID, we have carefully studied the Kaeng Sua Ten project and consider it to be feasible
as well as have an acceptable environmental impact.

However, we believe that in order toobtain an approval for the construction of such a project, we need a declaration on the EIA.
Nevertheless, we are confident that the Kaeng Sua Ten dam-when constructed-along with the*Manwan* dam will considerably benefit the water management of the Chao Phraya river
basin.

However, this decision has not yet been made by the government.

With regard to thesecond part of your question, the canal is currently operating efficiently.
5

What is the status of the EIA?

I understand that it has already been passed.

6

My colleagues have stated that in general, it can be regarded as having been passed; however,certain issues that I am unaware of are still pending.

7

When I was working with the RID, I was involved in the Kaeng Sua Ten project.

109

Although Iam now not with the RID anymore, in retrospect, I believe that if we are going to support thisproject, there are certain issues that need to be resolved.

This is because the study on the

Kaeng Sua Ten project focused on the project at a structural level and did not consider thecontribution towards flood mitigation.

The uncontrolled water in the Chao Phraya riverduring the wet season is more than 30 million cubic meters per year, and this is only in the wet
season; in contrast, the storage capacity of the Kaeng Sua Ten reservoir is approximately 1
million cubic meters.

Thus, while the Kaeng Sua Ten reservoir may be beneficial at the YomRiver basin, we still need to address the issue of whether it will be beneficial in flood
mitigation in the lower Chao Phraya river basin.
8

I think that this is a good time to evaluate the contribution of the Bhumibol and Sirikit dams interms of whether they have met the expectations of the feasibility study that was conducted
earlier.

I believe that Bangkok would have experienced severe flooding without these two

dams.
9

Regarding the Kaeng Sua Ten project, after our study on the developmental impact had
already been passed, the Chulalongkon University Report suggesting that the construction willaffect the animals living in that area was prepared approximately two years ago.
NGOs were a small power.
silent.

At the time,

Regardless, due to the nature of the issue the government was

Further, since the RID was responsible for the demand and supply of this project they

were eager to begin; hence, we were also silent.

Recently, however, we have all agreed on

the manner in which the construction will proceed because it was a good time to address
issues pertaining to flood mitigation.

Therefore, we gradually proceeded with thedevelopment and contacted several agencies such as the media.

However, it was proposedthat the final consent for construction would be given based on a comparison of the cost of
construction with the benefits.

Since our cost estimation focused only on construction anddid not include the mid-term effect or the livelihood of the people, it did not meet the required
cost benefit.
10Consequently, the government rejected the proposal to build the dams.

I believe that we are here representing various groups of people who are interested in flood
mitigation.

I am certain that collectively we have amassed considerable data as well as

knowledge pertaining to this issue.

I propose that Dr. Siriphong take this comprehensive

book, containing the pooled information, to the government.
11

I believe and hope that Dr. Siriphong is willing to accept this responsibility, and I am sure that
he is eager to actively contribute in this endeavor.

12

I believe that by the end of this discussion we will have reached a concrete conclusion.
Further, I would like to state that I support the idea of conveying this information to a higher
authority.

As Secretary of the National Water Resource Committee, I am willing to110

undertake this responsibility and will be communicating our message to the Deputy Prime
Minister.

In addition, I would like to invite some of participants at this meeting to aworkshop that is being organized by the Department of Water Resource and the National
Water Resource Committee.
13

I have been working on issues related to water management for a long time, and I would liketo confirm that the information presented here is thus far the best and most accurate.

Besides

the alarming flood forecast for Bangkok, I believe that the area around Nonthaburi will also
experience severe flooding.

As everyone is aware, the water in the Bhumibol dam has

already reached its maximum capacity; subsequently, water will be drained in order to protect
the dam.

In fact, even Pasak and Sirikit dams have reached their maximum capacity.

Although this information pertaining to the worsening situation cannot be verified, it is the
only information that is available.
14

I believe that the Dr. Pornsak’s forecast should be provided to Dr. Siriphong so that he is able
to use the information for the next meeting.

I believe that this prediction might be beneficial

in facilitating a reaction from the government.
15

I was in the water resource committee of the government of Thailand prior to my retirement.
I would like to comment on the Bhumibol and Sirikit dams.

I have been informed about

people complaining that the two dams are extremely big, and as a result, there is considerable
empty space and only two or three of the reservoirs in Thailand are full.

Thus, I would liketo reiterate the fact that the feasibility of the Kaeng Sua Ten project be determined.
16

I would like to make an observation.

During the last 30 years, that is, from 1977 to 2007, apattern with regard to floods has been noticed.
1980, we experienced severe floods.
severe floods.

In 1979, there was severe drought, but in

Then, in 1994, there was severe drought; in 1995,

Moreover, last year we experienced severe drought, and this year we areplagued with severe floods.

I found the cycle is 10 to 15years.

Based on this, I believe thispattern-severe drought, followed by severe floods will persist.

Thus, the people responsible

for allocating water should be aware of this pattern.
17

I believe that we will have to forecast the weather in advance by observing the temperature in
the Pacific Ocean.

The NOAA is currently working on this and has set up a station in the

Pacific Ocean for the same.

For example, before the end of last year, we were warned that

this year would be a La Nina year and that next year will be an El Nino year.

Unfortunately,

they only have a station in the Pacific Ocean and not in the Indian Ocean; hence, we areunable to register and benefit from it.
18

Forty years ago, research on the cycle of nature was common.

111

The sunspot was recorded,and its activity was used in forecasting.
been discussed.

However, after 1965, the cycle of the nature has not

In addition, I believe that observing the ocean temperature to predict

weather will be beneficial, and I hope that we are successful in this endeavor.
19

I would like to make one minor observation.
relating to flood management.

This is a symposium on the current policy

Given that we are confronted with municipal floods, Dr.

Pornsak’s presentation regarding the prediction of the current flood appears extremely
practical and urgent.

I would like to know if this is a voluntarily study or a government

study.
20

Typically, many forecast models are developed by our researchers or the technocrats.

I

believe that among us there are at least five or ten models, and Dr. Pornsak’s model is one ofthem.

I would like to ask Dr. Pornsak to respond to the question: Is this a voluntary study ora government study?
21

This is a voluntary study, although I have received support from the government in the form ofdata that was needed to make this model more accurate.

If I am provided with more data, I

aim to further develop this model and increase its accuracy.
22

I believe that several predictions have been made, including those by Dr. Suphot from theWater Resource Department and by the BMA.

I would like to ask Dr. Sutat to comment on

the same.
23

I would like to add to what Dr. Pornsak has stated.

At present, there are some models thatprovide the RID with the information that they need in order to make decisions; however, Dr.
Pornsak and I would like to provide them with further information in order to enable them tomake the correct decision at the right time.

Further, I would like to add that although myforecast for the discharge may have been ahead by one month, a skeptical analysis indicatedhigh discharge; this information has already been given to the RID.
24

I would like to direct my question to Dr. Siriphong.

In your presentation, you had mentioned

political view; I would like to ask you whether you think it exists in our present government?
25

On the October 12, the Deputy Prime Minister convened a meeting with certain people to draft
the national policy; he has agreed that flood mitigation in the highly economic areas will be
included in this policy, focusing on the prioritization of the project and the organization to be
responsible for the activities.

26

Hence, I believe that political view is present.

I would like to request Dr. Suphot to present the concluding remarks for this meeting.
Before we conclude, if no one has any more comments, I would like to present one more issue.

112

We already have three ministries involved in the water problem, namely, the Ministry ofAgriculture, the Ministry of Water Resource and Environment, and the Ministry of Interior,perhaps even the Ministry of Public Health and the National Committee of Water Resource
chaired by the Deputy Prime Minister.

I believe that the new government is willing to work

toward flood mitigation and that we should share our ideas and suggestions with theauthorities.

I would like to propose that only one institute or agency to be responsible forcoordinating or executing water related activities.
27

I believe that you have raised a very difficult issue; a problem that we are currently facing
while working at the National Water Resource Committee is that there are many ministers
with their own specific mandates.

Hence, if they are not pleased with the decision made by

the National Water Resource Committee, they are able to bypass the committee by goingdirectly to the cabinet.

Further, in our democratic society, regardless of the decisions made at

the governmental level, politicians like to benefit; often, they intervene and change theprioritization of the project plan or programs.

Thus, even though we have a central body,problems still exist.
28

Everyone in this room is already aware of the existing situation; moreover, this was theexperience with the last government.

I addressed this issue more from a business perspective

rather than that of a democratic government.
concern.

I believe that this is a good time to express our

On behalf of the Thai authority’s assembly, I would like to thank the participantsfrom Japan Science and Technology as well as those from China.
this symposium was Thailand and its problems.

I regret that the focus of

I am pleased that everybody participated inthis meeting and followed the presentations extremely well; I hope that the symposium will be
regarded as being successful and that you will continue to participate in it.
express my gratitude to everyone present here.

113

I would like to