BACKGROUND ON

Hydrological
Services		In JapanAND LESSONSFOR DEVELOPING
COUNTRIESFoundation of River & Basin Integrated
Communications, Japan (FRICS)ABBREVIATIONS
ADCP
CCTV
DRM
FRICS
GFDRR
ICT
JICA
JMA
GISTDA
MLIT
MP
NHK
SAR
UNESCO

acoustic Doppler current profilers
closed-circuit televisiondisaster risk management
Foundation of River & Basin Integrated
Communications, Japan
Global Facility for Disaster Reduction
and Recovery
Information and Communications
Technology
Japan International Cooperation Agency
Japan Meteorological Agency
Geo-Informatics and Space Technology
Development Agency
Ministry of Land, Infrastructure,
Transport and Tourism
multi parameterJapan Broadcasting Corporation
synthetic aperture radar
United Nations Educational, Scientificand Cultural Organization

Table of Contents
1. Summary  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
2. Overview of Hydrological Services in Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  7
2.1

Hydrological services and river management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.2

Flow of hydrological information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3. Japan’s Hydrological Service Development Process and Related Knowledge,
Experiences, and Lessons  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.1	Relationships between disaster management development and hydrometeorologicalservice changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2	Changes in water-related disaster management in Japan and required hydrologicalservice modernization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.3

Lessons learned from other mega-disasters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3.4

Tools used to solve problems and achieve goals  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.5

Evolution prompted by technology development  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

3.6

Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

4. Organizations Related to Japan’s Hydrological Services and their Relationships . . . . . . . 28
4.1

Changes in governmental and other organizations  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.2

Role-sharing and cooperation between the government and citizens . . . . . . . . . . . . . . . . . . . . . . . 29

4.3

The involvement of the private sector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4.4

Government’s relationship with mass media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4.5

Establishment of FRICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4.6

User groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

5. Application of Japan’s Knowledge, Experience, and Lessons to International
Cooperation Projects Relating to Hydrological Services  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.1

Technical cooperation projects up to the present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

5.2

Lessons learned from past technical cooperation projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

5.3

Case study of disaster management in Thailand’s 2011 floods . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.4

Issues for sustainable use of past project achievements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

6. How to Apply Japan’s Lessons toward Hydrological Service Modernizationin Developing Countries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.1	Use a holistic approach to disaster management to promote effective cooperation
among disaster management facilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.2	Both the future vision and the implementation plan should be realistic and keep
in mind the existing capacity of hydrological services in the country. . . . . . . . . . . . . . . . . . . . . . . . 42
6.3

Uncertainties in flood forecasting should be effectively communicated. . . . . . . . . . . . . . . . . . . . . 43

6.4

Development of hydrological services and systems should be driven by user needs. . . . . . . . . . 43

6.5

Hydrological services and river management should be institutionally integrated.  . . . . . . . . . . . 43

6.6

Long-term support is needed to ensure the sustainable operation of modernized systems.  . . . 44

ANNEX 1: ANSWER SHEETS TO QUESTIONNAIRE SEEKING FEEDBACK ONTECHNICAL COOPERATION PROJECTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
ANNEX 2: EXAMPLES OF TECHNOLOGICAL DEVELOPMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Summary12

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

1. Summary

Overview of hydrological services inJapanRiver and basin management covers various factors,
including disaster management, river water use,and conservation of the river environment. Anyof these factors involves a number of intricatelyintertwined stakeholders who may have different
needs. For example, during a flood, populations
located upstream versus downstream, or on the left
versus the right bank, may have different priorities toensure safety; flood management must, therefore,take a balanced approach to safety that is basedon integrated river basin management and takes all
relevant perspectives into account. Over time, efforts
to manage water-related disasters in Japan have led
to the concept of integrated river basin management
and to a mechanism allowing central management ofriver basins by river management authorities. These
approaches were institutionalized under the revisedRiver Law of 1964.
Integrated management of river basins requires
collecting/analyzing real-time hydrological data for
the whole river basin, as well as archiving/studyinghydrological data for appropriate management.
Japan built its system of hydrological services (anddeveloped needed technology) in order to meetthese requirements, as well as similar requirements
for water use management and river environment
enhancement. These attempts to promote moreadvanced integrated management of river basins
have provided the foundation of social and economic
development in Japan today. Integrated managementof river basins is not only the core concept in Japan’s
technical cooperation with developing countries, butalso part of a worldwide movement introduced in the
Rhine, the Thames, and other areas where localized
management was used in the past.

Based on its long experience and River Law, Japan
employs a unique river management system, inwhich river management authorities have centralized
control over rivers in the country and provide
hydrological services.
River management authorities (Ministry of Land,
Infrastructure and Transport, or MLIT, and prefectural
governments) accurately monitor facilities for rivermanagement, develop observation networks toprecisely monitor water levels and rainfall in thebasin, and forecast water levels and discharge. River
management authorities analyze a large amountof data and forecast floods and inundation. The
collected hydrological data and forecast information
are used by river management authorities themselves
and also delivered to municipalities, fire and police
authorities, and the Self-Defense Forces in an effort toprevent disasters from occurring, assist residents inevacuating safely, and provide emergency response
quickly.

Japan’s hydrological service
development process and related
knowledge, experiences, and lessons
learnedIn Japan, disaster risk management (DRM) is
modernizing as a result of various influences,including socioeconomic changes, large disasters,
technological breakthroughs, and other factors.
The modernization has been a movement towards
integrated approaches to disaster prevention (asopposed to individual or areal approaches); towards
approaches that consider inundation (as opposedto those that do not); and towards approaches that
account for floods exceeding designed floods (asopposed to designed floods based on historicalones). With its hydrological services integrated with

Summary3

river management, Japan has smoothly coped withthese changes.

Organizations related to Japan’shydrological services and theirrelationships

Japan has experienced other types of disasters
besides floods, and it has incorporated knowledge,
experience, and lessons from each disaster toimprove its overall capacity to cope with disasters.
Some of these general countermeasures are also
applicable to floods: (i) To avoid fatalities, analyze
how structures behave when they are hit by external
forces far larger than those used in conventional
structural design; (ii) to improve forecasting, carryout simulations based on data assimilation; and(iii) classify events in terms of danger levels that
correspond to the actions that recipients should take.

A significant change in governmental systems inJapan occurred in 2001, when the government
decided to restructure its agencies and ministries.
The Construction Ministry and the Meteorological
Agency became part of the MLIT. The Cabinet
Office was created to handle important government
matters, including DRM, and it began to develop
disaster management policies and to coordinate
related agencies and ministries.

Technological progress has improved hydrologicalobservation, partly in response to users’ needs for
greater accuracy. Some technologies developedin different areas have successfully been usedin hydrological observation; examples are radar
technology that allows observation of the conditionof raindrops over a widespread area, and information
technology that has enabled in-depth analysis ofvoluminous data, more user-friendly interfaces, andprovision of information with handheld devices.
The progress of disaster management in Japan waspartly driven by the need to solve certain problems,
including (i) a decline in the capacity to cope during
disasters, arising from excessive expectations
for DRM structures; (ii) difficulty in deciding whento order evacuation and issue advisories; and (iii)difficulty in taking responsibility for actions basedon uncertain information. The modernization ofhydrological services contributed to solving some ofthese issues.

To minimize disaster damage, three components
must be in place and function efficiently: public
assistance (governments provide assistance
before a disaster and crisis management during adisaster), self-help (people protect themselves), andmutual support (people support one another at thecommunity level). A good example of mutual supportin Japan is cooperative efforts by local residents tofight floods.
In Japan, the mass media, such as TV stations, play
an important role in communicating information to
the public during disasters. In an emergency, theadministration and the mass media cooperate to
make sure that people receive necessary disasterrelated information.
The demand for hydrological information iscomparably limited in normal times, and private
corporations have avoided involvement inhydrological services, because they are not profitable,
even if they are necessary especially during floodtimes. Thus when the Foundation of River & Basin
Integrated Communications (FRICS) was establishedto provide such information, it was with funding fromthe government as well as organizations in the public
and private sectors.
At present, hydrological information is used for
operating and managing structures such as dams
and water gates, monitoring unusual events during
floods, and forecasting inundation. This is widely
shared by local governments, which make decisions
on evacuation orders and advisories; organizations

4

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

that support disaster management efforts of local
governments; government headquarters for disaster
control, which are activated in case of large-scaledisasters; organizations that operate lifeline utilities(e.g., electric power, gas) and traffic infrastructure(e.g., expressway, railway); and mass media.

Application of Japan’s knowledge,
experience, and lessons to international
cooperation projects relating tohydrological services
In Japan, the organization that manages rivers,
including construction works, provides hydrologicalservices such as hydrological observation and flood
forecasting. The institutional setup is similar inneighboring countries such as the Republic of Korea(where the relevant organization is the Ministry ofConstruction) and the People’s Republic of China(where the organization is the Ministry of Water
Resources). In many cases, if part of the budget
for structural measures was instead earmarked for
nonstructural measures, that would be enough todevelop a flood forecasting system. In China andKorea, the flood forecasting systems were properly
recognized as DRM measures and the necessary
budget was provided to establish them.
On the other hand, in many developing countries,hydrological observations and analysis are carriedout by organizations that do not manage rivers.
In these cases, even if there is collaboration, thechanging needs of management organizations that
actually use the observed data may not be flexibly
reflected in the observations. River managementin the Philippines was under the jurisdiction of the
Ministry of Public Works and Highways, and theflood forecasting project supported by the Japan
International Cooperation Agency (JICA) was
carried out by the Philippine Meteorological Agency(PAGASA). This arrangement might be one of thereason that flood forecasting in the Philippines was
not properly budgeted, and that the forecasting
system was not well maintained in the past..

Implication of Japan’s experiences inmodernizing hydrological services fordeveloping countries
1. Consider a holistic approach to disastermanagement to promote interactive, effective
cooperation among disaster management
facilities.
The modernization of hydrological services
should be carried out with clear purpose, andwith the understanding that it will enhancedisaster management by providing improvedhydrological information.
2. Both the vision for the future and the specificimplementation plan should be realistic andshould keep in mind the existing capacity ofhydrological services in the country.
Countries in which the economy is growing
rapidly may need different sets of hydrologicalinformation at different stages of development,with the contents, accuracy, and quality of
information improving over time. Institutionalarrangements for hydrological services should
be structured to capture and respond to suchchanging needs quickly and flexibly.
3. Uncertainties in flood forecasting should be
effectively communicated.
Forecasting of natural hazards involves
uncertainties. Since structural measures alone
are not sufficient to deal with all disasters,
nonstructural measures such as forecasts
and other types of information are particularly
important for reducing damages as much as
possible.
4. Development of hydrological services andsystems should be driven by user needs.
Information delivered through hydrologicalservices should be user-oriented and shouldreflect the needs of different individuals andgroups in acting and making decisions.

Summary55. Hydrological services and river management
should be institutionally integrated.
Hydrological services are inseparable fromwater management: they do not just deal withobserved data of rainfall, river water levels,and river discharge, but change their contents
according to different water management
issues. Therefore, institutional arrangements
should seek to ensure not only data connection,
but also organic links between institutions;
ideally hydrological services and water
management should be integrated.
6. Long-term support is needed to ensure thesustainable operation of modernized systems.
Information is helpful only when it is used, andonly then are any problems with it noticed.
Technical cooperation should be extended
beyond the stage when new hydrologicalservices are put in place to include the stage
when information is successfully delivered.

6

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

2. Overview of Hydrological Services in Japan

2.1 Hydrological services and rivermanagement
River and basin management covers various factors,
including disaster management, river water use, andconservation of the river environment. Any of thesefactors involves a number of intricately intertwined
stakeholders who may have different needs in ariver basin. For example, during a flood, populations
located upstream versus downstream, or on the rightversus the left bank, may have different priorities for
ensuring safety; flood management must therefore
take a balanced approach to safety that is basedon integrated river basin management and takes all
relevant perspectives into account. Over time, efforts
to manage water-related disasters in Japan led to theconcept of integrated river basin management andto a mechanism allowing central management orriver basins by river management authorities. These
approaches were institutionalized under the revisedRiver Law of 1964.
Integrated management of river basins requires
collecting/analyzing real-time hydrological data for
the whole river basin, as well as archiving/studyinghydrological data for appropriate management.
Japan built its system of hydrological services (anddeveloped needed technology) in order to meetthese requirements, as well as similar requirements
for water use management and river environment
enhancement. These attempts to promote moreadvanced integrated management of river basins
have provided the foundation of social and economic
development in Japan today. Integrated managementof river basins is not only the core concept in Japan’s
technical cooperation with developing countries, butalso part of a worldwide movement introduced in the
Rhine, the Thames, and other areas where localized
management was used in the past.

Based on its long experience and River Law,
Japan employs a unique and highly effective rivermanagement system, in which river management
authorities have centralized control over rivers in the
country and provide hydrological services.

2.2 Flow of hydrological information
The flow of hydrological data collected in river basins
and used in integrated water management anddisaster management activities is shown in Figure 1(see page 8).
River management authorities (MLIT, prefectural
governments) accurately monitor facilities for rivermanagement and develop observation networks
to precisely monitor water levels and rainfall in thebasin.
Observation stations have been set up by
river management authorities and are in placethroughout the country (Table 1, see page 9).
For river management authorities to properly
manage rivers, they need to monitor and forecast
discharge accurately, and their observation stations
are complemented by the Japan Meteorological
Agency (JMA) observation network. Radar rainfall
gauging systems, which contribute to more detailed
monitoring of conditions and forecasting of floods,
are also being installed nationally. C-band radar now
covers the entire country, and MP(multi parameter)
X-band radar covers city areas. Composition of MP
X-band and MP C-band radar, which will provide far
more accurate observation, is now under way (Figure
2, see page 9).

Overview of Hydrological Services In Japan7

Figure 1. Overview of Hydrometeorological Services in Japan

JMA

River ManagmntAuthorities (MLIT, Pref.)Agricultural
Dam/Weir

Water Level/Discharge obs.

Rainfall obs.

River Discharge
analysis

InundaonIn
analysis

Hydropower
Dam/Weir
Water Supply
Dam/WeirMet. Services

Hydro. Services

Rainfall obs.
Other Met. Obs.

Analysis
Numerical Weather Predicon Model etc.

Flood Forecast

Met. Forecast (Rainfall/Wind and others)

Water Level-based
Flood Forecast/Warning

Water Management(Flood me)
Operaon of dams/water
gates and others,
Flood Fighng, Sandbagging,Emergency Drainage Pump
Vehicles(Drought me)
Operaon of dams/water
gates and others,Drought Coordinaon,
Emergency Water
Conveyance(Normal me: For Planning)
River Improvement/Dam
Construcon and others,
Land use Guidance

Rainfall-based
Flood Forecast/Warning

Pref. ,FDMA,etc
Flood Fighng Warning

Dam Discharge
Warning

Flood Fighng Corps(community
organizaon)

Internaonal
Data/Informaon exchange

MunicipaliesDisasterPrevenon
Acons

Evacuaon
Advisory/Order

Rainfall
Forecast/
Warning

Private Sector
and Others(NonGovernmental
Services)
Mass Media
M

Residents/Relevant Organizaons
Socio-economic Sectors(Companies etc.)

Note: In addition to channels shown here, almost all information is delivered through the website of each organization. Colors of arrows show data andanalytical information (blue), order/request (brown) and forecast/warning (red).

8Modernization of Hydrological Services in Japan and Lessons for Developing Countries

Table 1. The number of hydrological observation stations
River Management
Authorities

JMA

C-band Radars

26

20

X-band MP Radars

39

Telemetric Rain

7,533

Water Level

6,935

Others

2,106

CCTV

9,514

Highway Bureau

1,303

1,176

87

188
12,123

Note: Data are as of March 31, 2015. Most data are updated every 5 (C-radar) or 10 (telemeter) minutes.

Figure 2. Observation area of radar used by Water and Disaster Management Bureau

Observaon area of C-band radars (26units)
Observaon area of X-band MP radars (39units)

River management authorities analyze a large
amount of data and forecast floods and inundation,
as described above.
River management authorities conduct simulations
for water-level forecasting using real-time data anda runoff analysis model whose main input is basin
rainfall and upstream water levels. Their inundation
forecasting, on the other hand, simulates multiple
flood cases by setting inundation risk points along
the target river at equally spaced intervals. When an
inundation actually occurs, the closest simulatedcase is applied to forecast the development of
the inundation. Such prior simulation is usuallynecessary, because calculation is not instantaneous.
Real-time inundation simulation is possible, however,in the case of the Tone and other large rivers
floodwaters take days to expand over wide areas.
To prevent or mitigate damage due to river floods andother related events as they occur, river management
authorities and flood-fighting organizations cooperate
closely with many other organizations, including
prefectural and other local governments, fire andOverview of Hydrological Services In Japan9police authorities, and the Self-Defense Forces. Theirgoals are to prevent disasters, assist residents inevacuating safely, and provide emergency response
quickly. Equally critical to reducing disaster damageis the proper issuance of evacuation advisories andorders by mayors of local governments.
Forecasts of river water levels and discharges provide
information directly related to those organizational
efforts. The MLIT and prefectural governments, which
are acknowledged as river management authorities,
collect and analyze data and information on riverhydrology, such as water levels and discharges, andon the condition of river structures. They forecast
river water levels and discharges for over 400 rivers
that have been designated for flood forecasting bymeans of a nationwide network built for accurate
observation of rainfall over each river basin. In
addition, they officially release such forecasts with
JMA, coupling river flood forecasts with rainfall,
typhoons, and other meteorological data andforecasts provided by the agency. River management
authorities issue flood warnings and dam discharge
warnings.
For more effective use of river flood forecasts during
flooding, authorities should already have analyzed
and planned evacuation and other relevant actions
to be taken in the face of flooding, and should haveinformed residents of these actions through various
means, such as hazard maps.

During an actual flood, river management authorities
operate structures such as dams and water gates,
deploy flood-fighting to prevent levee breakage, anddrain inundation water using pump vehicles, evenoutside the river area. In times of drought, in addition
to operating dams/water gates, river management
authorities deploy emergency water conveyanceand coordinate among water users. When normal
conditions are in effect, authorities construct andmaintain structures for river management, such as
levees and dams, and collaborate with municipalities
on land use guidance.
For all these aspects of water management
conducted by river management authorities,hydrological information (including river waterlevels, discharge, basin rainfall, and forecasts) is
indispensable.
The organizations that use hydrological information
to operate facilities and execute disaster response
not only cooperate with those that collect and analyze
such data, but in some cases have also tailored theinformation to their own needs. These cases should
be taken into consideration when planning themodernization of hydrological information services indeveloping countries.

For flood forecasts to be utilized in the evacuation of
every resident, information must be received quickly.
An information delivery service for smartphoneusers, including information on flood hazard maps,
is scheduled to start in 2016 as an option for
individuals.

10

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

3. Japan’s Hydrological Service Development
Process and Related Knowledge, Experiences,and Lessons

3.1 Relationships between disastermanagement development andhydrometeorological service changes

by validating them with observed data. These efforts
continue today.

Hydrometeorological services have been evolving
in Japan as an integral part of DRM alongwith other measures. The following provides ahistorical overview of the progress of Japan’shydrometeorological services.

1961
In 1959, Isewan Typhoon hit Japan and left 5,098
people dead or missing—the largest number ofcasualties after the Meiji era (1868-1912). The
disaster led to the enactment in 1961 of the Disaster
Countermeasure Basic Act, which systematicallyaddressed issues regarding DRM and development
of disaster management plans, designationof disaster risk areas, issuance of evacuation
advisories and orders, disaster response, and postdisaster restoration. It also defined the roles andauthority of the national and local governments,
public organizations designated by the Disaster
Countermeasure Basic Act, general public, andoutlined financial measures. This legislation
facilitated further and more systematic improvementof hydro-meteorological services.

Before the 19th century
The main purpose of disaster management before
the 19th century was to protect one’s own settlement.
The hydrometeorological information collected andused was limited to water levels of nearby rivers andweather forecasting based on traditional knowledge.
Early 20th century
Because of conflicts of interests between upper andlower reaches and between right and left banks,
river management authorities realized the need to
manage river basins using an integrated approach.
Hydrological observation covering the entire river
system, including the main stream and its tributaries,
was begun in order to plan and implement river
improvements that would ensure balanced protection
throughout the river basin.
1955
Flood forecasting began with the goal of avoiding
or mitigating flood damage. In hydrologicalservices, efforts were made to develop forecasting
technology, implement systems to collect dataneeded for forecasting, and improve data accuracy

Late 20th century
Dramatic progress in information and communication
technology (ICT) made it possible to process a large
quantity of data at a higher speed, which in turnenabled more accurate analysis of current conditions
and more accurate forecasting. In addition, thecoverage of information networks expanded, allowing
many more users to gain access to information.
Observation technology also advanced significantlywith the installation of radar rain gauges and the useof satellite images and SAR (synthetic aperture radar)for observation.

Japan’s Hydrological Service Development Process and Related Knowledge, Experiences, and Lessons

11

21st century
Traditionally, hydrological data collected by observing
natural phenomena were analyzed and provided
to residents and relevant offices to help them takeappropriate actions, such as evacuation, in the eventof flooding. However, in the effort to use hydrological
data more effectively in DRM, authorities havestarted to divide hydrological and meteorologicalinformation into several levels and provide it at stages
corresponding to actions that residents should take ina given situation.
Reviewing the historical development of hydrologicalservices in Japan should help developing counties
both to assess the status of their services as they
modernize, and to discuss and plan practical goals
and strategies.

3.2 Changes in water-related disastermanagement in Japan and requiredhydrological service modernization
In Japan, the modernization of DRM has
been influenced by various factors, including
socioeconomic changes, large disasters,
technological breakthroughs, among others.
Historical changes in flood disasters, and themodernization of hydrological services that took
place in response to them, are discussed below andsummarized in Figure 3.

3.2.1 From individual/areal disaster prevention to
integrated disaster prevention
In Japan, levee building to prevent flood disasters
started hundreds of years ago. Before the Edo era(1603–1868), circle levees, which were usuallydesigned to protect only the builders’ own community,
were very common. Over time, however, communities
located upstream and downstream, or on the rightand left banks, began to have conflicts over safetyissues. To solve such conflicts, flood management
policy was revised drastically to call for constructionof continuous levees, not circle levees, on both sidesof rivers to contain floodwaters within river courses
and to discharge them to the sea as fast as possible.
One example of such conflicts is the rehabilitation
work carried out after the 1910 flood that damaged

12

the Tokyo area. Chujo-tei, a type of levee built on theright bank of the Tone River, had long prevented thefloodwaters that overflowed at the narrow section
from spreading over the downstream parts of theriver and inundating the upstream parts. After theflood, the local prefectural assembly and residents
were divided over the rehabilitation of the Chujotei levee. Some local people even had a violent
confrontation with the police, forcing their way into
the prefectural government office. To address thisconflict, the project for the Tone River was revised towiden the narrow section and build continuous levees
that would allow floodwaters to flow down to the sea
safely.
Integrated river basin management aims to provide
each riparian community with the same level ofprotection against floods, and so must ensure thatfloodwaters are safely discharged in a channel
walled by continuous levees. Meeting this objective
requires that river improvement plans be designed
consistently over the entire river system, including
tributaries, and implemented as agreed on. In fact,
the revised version of the River Law, enacted in 1964,
proclaimed that integrated river basin management
was the fundamental concept for high- and low-water
management of rivers in Japan.
As demands for water resources increased, moredams were constructed in the upper reaches of rivers.
In addition, as river improvements progressed andflood safety increased, urbanization accelerated andbegan to reach areas immediately along rivers, which
made the acquisition of land to control floodwaters
very difficult. After the Second World War, plans weredeveloped by river management authorities (theMinistry of Construction or prefectural governments)
to construct dams and retarding basins in the upper
reaches to store some of the floodwaters temporarily.
In response, the Specified Multipurpose Dam Act wasenacted in 1957.
To develop plans based on the concept of integrated
river basin management, it became necessary tocollect hydrological data from the entire river basin.
These plans were partly a response to rising demand
for water resources, and included efforts to control

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

Figure 3. Changes in water-related disaster management in Japan from the 18th century to present,
and required hydrological service

19C.

䡚18C.

20C.

21C.

Hydrological datausedA shift in level of decision-making and cooperation(1) From individual/areal disaster prevenon to the integrated disaster prevenon.
Individual prevenon
Mound houses

Areal prevenon
Circle levee

Integraon of Water systemConnuous levee

Elucidang conflict(e.g.䠖Chujo bank)

The new River Law (1964)

River course widening
Levee/revetment

Underground flow,
and flow storage

Dam

Difficulty of land acquision

Local water level inthe past floods

Hydrological data of thewhole basin area

Weather forecast
based on experience

Real-me hydrological informaon
Telemetry
Radar rain gauge

A shift in consideration of flood hazards(2) From disaster prevenon without consideraon of inundaon to with consideraon of inundaon
Facility development

Minimize damage even in case of the inundaon
Super levee/Secondary levee/
Waterproofing

Less recognion to the flood
Amendment of the FloodControl Act (2005)

Hydrological data on rivers

Hydrological informaon
including inundated area
Inundaon area/ water depth
Real-me hydrological informaon

A shift in assessing risks(3) From disaster prevenon based on past events, through designed floods, to floods exceeding designed floods
River works according to
the past events

River works plan basedon designed flood

Correspond to the disasterbeyond the designed flood
Great Hanshin-Awaji
Earthquake (1995)

Past observed data

Probabilisc/stascal
processing of observed data

Probable maximum eventsesmated from observed data

Japan’s Hydrological Service Development Process and Related Knowledge, Experiences, and Lessons

13flooding and manage water resources in river basins.
Since 1938, national data on rainfall and discharge
have been published annually to meet demands
for hydrological data. Since controlling the quantityof water is the most important factor in planningand managing dam construction and operation,observation of discharge has drawn particularattention since then.

The primary reason to modernize hydrologicalservices in developing countries is to contribute toflood and water use management. Integrated river
basin management is essential to addressing thesechallenges, and modernization efforts should bedesigned to realize this type of management.

Table 2. Changes in prevention approaches
Age

P
A
S
T

Approach

Implementation• Protection of houses against flood
By family members– Raising of the house site byembankment/stone masonry– Provision of the private shelter for flood
and attic in an evacuation place– Bamboo plantation around the house– Preparedness of a lifeboat in each house• Protection of villages against flood
By the village– Construction of circle levee around thevillage

Hydrological Information
Used
Water level at local levees
Empirical forecast of theflood

Conflicts of interest between upstream and downstream/left bank and right bank
Example: Reconstruction of the Chujo-tei levee broken by 1910 Tokyo flood

P
R
E
S
E
N
T

14

• Flood prevention by continuous levees(protection of a basin area)– Cope with an actual flood at an initial
stage

Central/local
governments
Regulated by the (old)River Law

Recorded values of past
floods (water level, etc.)• Flood protection based on integrated river
basin management– Targeting a planned flood, processed
statisticallyCentral/local
governments
Regulated by the new
River Law

Hydrological data duringa certain period of pasttime (analysis is required)Difficulty in site acquisition for setting a wide river course, which is especially necessary indownstream city areas• Flood control integrating the dams andreservoirs in upstream basin area
– Example: The Revised River
Improvement Plan for the Tone River
System in 1949

Central/local
Real-time data required
governments
for dam operation
Specific multipurpose(Telemeter, radar)dam, regulated by the law

Modernization of Hydrological Services in Japan and Lessons for Developing Countries3.2.2 From disaster prevention without
consideration of inundation to disaster prevention
with consideration of inundation
In Japan, people used to regard river floods as thenorm and had local coping strategies in place to deal
with them. As time passed, continuous levees werebuilt to contain floodwaters within the river course
and upstream dams and retarding basins wereconstructed to control floodwaters.
Since building structures such as levees takes a longtime, some areas may suffer serious damage before
completion of improvement projects, which aredeveloped based on occurrence probability. Moreover,even after such projects are completed, there isalways a possibility that a disaster exceeding thedesign scale may occur. It is impossible to contain
floodwaters completely within the river course, andso both structural and nonstructural measures
should be in place to minimize damage when aflood actually occurs. Where river embankments areconstructed of soil, for example, a flood exceeding
the river’s capacity could cause a breach and leadto catastrophic damage (see Figure 4), whereas
super-levees with a very wide crest would not breacheven during flooding and hence would minimize
the damage. In addition, even under the same
phenomenon of inundation, damage can be reduced
if appropriate evacuation is guided. Figure 5 (seepage 16) illustrates the process of reducing damage
with nonstructural measures such as the provisionof information.

Figure 4. Catastrophic damage resulting from a flood exceeding the capacity of a river

Damagee.g. 䠍/䠍䠌䠌 years ofprobability scale
Catastrophic
damageExceeding flood countermeasures
to prevent dike break in case of overflow
䠄Super levee/embankment, etc.䠅

Capacity Disaster of 䠭䠎 䠄Disaster of 䠭䠏䞉䞉䞉䠅of 䠭䠍

Flood scale

Countermeasures 䠄Countermeasures of 䠭
of 䠭䠎
䠏䞉䞉䞉䠅

Japan’s Hydrological Service Development Process and Related Knowledge, Experiences, and Lessons

15

Figure 5. Process of reducing damage with nonstructural measures

These measures are disaster prevention with consideration of inundation, in which hydrological information on
areas outside the river, such as expected inundation area and depth, is observed, analyzed, and delivered.

Figure 6. Forecast of inundation area and the inundation depth

The Minister of Land, Infrastructure, Transport andTourism shall notify the relevant prefectural
governors the situation of the rivers, concerning
rivers within two or more prefectural areas, byindicating the water levels or flow volumes, orareas flooded by overflow and water depths
therein after overflow of rivers, as well as todisseminate the above to the public, asking forcooperation of the media as necessary.
（The Flood Control Act, Article 10 Paragraph 2）
Forecast of inundation
area of ARAKAWA river

As explained, developing countries should design hydrological services to provide hydrological information onrivers and areas outside of rivers, including inundation areas.

16

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

Table 3. Views on flood/inundation
Age~19 C.
20 C.

P
R
E
S
E
N
T

Views on Inundation
Inundation happens• Structural measures assuming noinundation– Flood should be controlled in a river– Inundation to be flown outside the river
is not assumed

Related Events

Specific Measures

Flood management perhouse/village

Indoor preparation of alifeboat• Establishment of the
new River Law• Conventional River
Development Basic
Policy(Determination of thedevelopment levelaccording to rivers.)• The flood cannot be contained completely • Progress of rivermanagement• The period of time
without a large-scaledisaster has continued• Large-scale waterrelated disasteroccurred frequently• Countermeasures to minimize damage• Revision of the Flood• Control of inundated
are necessary, even if the disaster occurs
Protection Act (2005)
water:– Regulates– Maintenance ofannouncement/
secondary levees,
Evolution of Floodplain risk management
dissemination about
utilization of continuous
inundating area, water banks, etc.
depth, etc.
• Arrangement of land
– Regulates
use:
dissemination of– Arrangement of land
information on riveruse/building methods
water levels
for geographic areas– Requires distributionthat will suffer seriousof flood hazard maps
damages• Reinforcement of thewarning/evacuation
system:– Maintenance of
information collection/transmission system,
securing evacuation
place/route, etc.
– Evolution ofhydrologicalinformation including
inundation areas

Japan’s Hydrological Service Development Process and Related Knowledge, Experiences, and Lessons

173.2.3 From disaster prevention approaches basedon past events, to approaches based on designed
floods, and finally, based on events exceeding
designed floods
There have also been changes to the process used
to determine the design external force for planningof flood control structures. Determining the scaleof a design external force was done to protect
communities from flooding equivalent to what they
had once experienced. In practice, levee heights wereusually decided according to heights of past floods.
However, building levees that can withstand a flood
similar to historical floods may not be a solution,
because levees may breach and serious damage
may result once a flood exceeds the past scale. As
illustrated in Figure 7, planning and building levees inthe traditional way may allow flood damage to recur,
and the implementation of measures will tend to bereactive.

occurrence probability requires statistical analysis
of hydrological data collected from the entire river
basin, which in turn requires the accumulation ofhydrological data for a long period of time. Because
the basis for design external forces has shifted frompast flood events to occurrence probability, archiving
hydrological data has further accelerated.
These days, large-scale disasters are occurring that
far exceed the scale calculated using past data. Thus,
in addition to planned countermeasures based on acertain occurrence probability, the maximum probablescale is assumed, and countermeasures intended
to avoid catastrophic damage in such a case are
deployed in parallel.
In developing countries, where archived hydrological
data are not sufficient, attempts should be madeto substantiate the hydrological data requiredfor preparing accurate plans, and to identify the“maximum probable” disaster not based on past data.

To avoid this problem, structural improvement plans
should be developed based on a level of occurrence
probability that will cope with floods larger than past
events; and structures should be built and maintained
according to such plans (Figure 8). Calculating adesign external force based on a certain level of

Figure 7. Tendency of implementation to be reactive

Figure 8. Structural improvement plans developed
based on occurrence probability

e.g. １/１００ years ofprobability scale
DamageDyke break
Catastrophic damage

DamageCatastrophic
damagePlan setting in prospect of a future
ﬂood・Catastrophic relation still remains
・Taking long time for preparation（Cost/ Land）

Repetition offollow-up measures

Capacity Disaster of Ｑ２ （Disaster of Ｑ３・・・）
of Ｑ１
Countermeasures （Countermeasures of Ｑ３・・・）
of Ｑ２

18

Flood scale

Capacity Disaster of Ｑ２ Plan with Ｑpof Ｑ１
Countermeasures Countermeasuresof Ｑ２with Ｑp

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

Flood scale

Table 4. Scale of disasters to be targeted
AgeTargeted Disasters

Related Events

Concrete/Practical
Measures

Structural measures correspond to past
(actual) floods; recurrence was to beprevented.
P
A
S
T

BUT
Damages would reoccur when the flooding
went beyond the past records.
Damage beyond conventional scale would
occur.
Makeshift solution
Formulate the scale of flood to be addressed: Establishment of the new Conventional River
To be able to cope with the floods of aRiver Law
Development Basiccertain scale, if all of the rivers are controlled.
Policy/Development Plan
(Determination of the
BUT
development scale,
Flood occurs when the facilities were halfaccording to theestablished.
importance of rivers)
Flood beyond the planned scale occurs.
• Comprehensive flood
control measures• Super-levee• Hazard map• Enhancement ofevacuation information

Damage would become bigger

P
R
E
S
E
N
T

Countermeasures against the floods
exceeding the designed level would be
required.

• Heavy rains without
past precedent occurred
frequently.
• Huge earthquakes suchas the Great Hanshin
Earthquake, the Great
East Japan Earthquake,etc., occurred.

Hydrological analysis
considering inundation(expected inundation
areas, depths)
Revised Flood Protection
Act (2015)(Countermeasuresagainst supposed flood,inland waters, and hightide of the maximum
scale [Nonstructural
measures])

Japan’s Hydrological Service Development Process and Related Knowledge, Experiences, and Lessons

193.3 Lessons learned from othermega-disasters
Japan has experienced other types of disasters
besides floods, and it has incorporated knowledge,
experience, and lessons from each disaster toimprove its overall capacity to cope with disasters.
This section outlines recent mega-disasters andtheir impacts on water-related disaster reduction
strategies.
Great earthquakes
Japan is prone to great earthquakes. Since the Meiji
era alone, a dozen earthquakes have occurred invarious parts of the country, claiming the lives of
thousands of people: examples include Kanto (1923),
Hanshin-Awaji (1995), and Great East Japan (2011).
Conventional structural design ensures structuralsafety and prevents serious damage even when
the structure is hit by a certain level of anticipatedexternal force (“Level 1” force). However, in the Great
Hanshin-Awaji Earthquake in 1995, a large numberof structures collapsed in response to tremors
exceeding the scale of the anticipated external
force. This event showed that to avoid fatalities, itis necessary to analyze the possible behavior ofstructures when they are hit by a far larger external
force (i.e., “Level 2” force) than the force used forconventional structural designing (“Level 1”).
This lesson has been applied to the field of flood
disaster management. A typical example is theconstruction of “hard-to-collapse” levees, which aredesigned not to breach easily even during flooding.
To further incorporate this concept into flood
management projects, it will be necessary to figureout how to determine the scales of external forces
larger than those of conventional design forces.
Great tsunamis
Since the Meiji era, Japan has on three occasions
suffered catastrophic damage and extensive loss oflife from great tsunamis.
The conventional approach to great tsunamis was
to issue forecasts and warnings based on tsunami
simulations using seismic movement. These

20

simulations can contain significant errors. People
know the existence of the errors, and are unwilling toevacuate. The Great East Japan Earthquake initiateda shift away from this conventional approach tosimulation. Currently, conducting simulations basedon observed data after the seismic movement are
assimilated for more accurate forecasting. Suchsimulations include those based on changes intidal level of the near waters around Japan. The
combination of multiple types of simulation is
expected to improve overall forecasting accuracy.
The same is the case in forecasting flood disasters.
In addition to simulation based on rainfall forecasting,which may contain a high level of uncertainty,
simulations using fact data such as observed
rainfall and water levels in upper reaches—that is,data collected from phenomena very closely related
to the occurrence of the flood—are now strongly
encouraged.
Volcanic eruptions
Many active volcanoes exist in Japan and continue
to cause damage. In 2014, Mt. Ontake in Nagano
Prefecture suddenly erupted, claiming the lives of
58 hikers, the largest death toll in Japan since theSecond World War.
In Japan, a volcano’s danger level is quantitatively
presented, but the figure is not based on the scaleand extent of volcanic impact. Instead, the five levelsof warning are based on how hikers and residents
living nearby should act at each warning level.
This approach to classification, in which danger levels
correspond to recommended actions, has also been
applied to prevent damage by other types of disaster.
In 2007, when the volcanic danger levels were set
up, flood forecasting was also revised, and warninglevels were set up that more easily translated into
specific actions. Sediment disaster management
also employs strategies from other areas of disastermanagement, such as establishing sediment disasterrisk and high-risk areas, informing residents of
sediment disaster risk in each area, and regulating
construction and other relevant activities in risk areas.

Modernization of Hydrological Services in Japan and Lessons for Developing Countries3.4 Tools used to solve problems andachieve goals
For proper management of flood events, anintegrated approach to disaster prevention andmitigation is essential: structural and nonstructural
measures must work in harmony. The basic
principles of disaster prevention/mitigation,
applicable anywhere in the world and against any sortof disaster, are these:
1. Keep settlements out of dangerous places,
so as to avoid damages even if phenomena
occur (e.g., land use control, earthquake-proof
building, private shelter for flood)
2. Defend assets with disaster prevention
facilities, or adjust phenomena (e.g., dyke,
estuary water gate, dam)
3. Escape from (or provide for rescue from)dangerous situations (e.g., evacuation, damage
alleviation actions, rescue, early warning)
After the Great East Japan Earthquake in 2011,
there was an emphasis on integrating effective
nonstructural measures with structural measures,and on seeking how best to combine them (Figure 9).

Table 5 (see page 22) describes measures mobilized
for flood prevention in Japan, including laws,
systems, institutional arrangements, technologies,
and budgets.
Structures for preventing inundation include
improvement of river courses (embankment,
dredging, etc.), dams, reservoirs, floodways, erosion
control facilities, and sewerage. These are developed
based on laws such as the River Law, Specified
Multipurpose Dam Act, and Erosion Control Act. In
order to achieve balanced facility development, witha view to integrated water resource management,
the River Law stipulates that a basic policy anddevelopment plan be created for each river basin.
Rivers are classified based on their importance, andthe national government and local governments
share the responsibility of development andmanagement of rivers. To prevent a wide disparity
in the development levels of rivers, the national
government takes responsibility for the development
and management of rivers’ most important sections.
The national government subsidizes projects
executed by local governments as well.
Measures for averting/reducing damage in case ofinundation include controlling the use of land at risk

Figure 9. Ideal mix of structural measures and nonstructural measures• Keep settlements
out of dangerous
places so as to avoid
damages even if
phenomena occur
Land use control
Earthquake-proof building
Private shelter for flood

Supplement each other

Evaluate as integrated risk /effect• Defend assets
with disasterprevention facilities• Adjust phenomena
Dyke
Estuary water gate
Dam

• Escape fromdangerous situation
Evacuation
Damage alleviation actions
RescueEarly warning

Japan’s Hydrological Service Development Process and Related Knowledge, Experiences, and Lessons

21

Table 5. Different tools for flood damage reduction
Development andMaintenance ofFacilities(Prevent inundation)

Regulation, Instruction(No damage in case ofinundation)

Evacuation, Assets
Protection Damage
Alleviation Actions(Dealing with disasters)• Improvement of rivercourses (embankment,
dredging, etc.)• Development of dams,
reservoirs, floodways• Erosion and SedimentControl facilities, etc.
• Sewerage• Proper land use• Encouragement offlood-proof building• Damage estimation• Establishment of
warning evacuation
system• Formulation/dissemination of hazard
maps• Implementation of
emergency response
drill• Rescue/relief• Emergency measures

Laws/Acts• Disaster
Countermeasures BasicAct• River Law• Specified Multipurpose
Dam Act• Water Resources
Development
Organization Law• Erosion Control Act, etc.

• Disaster• Disaster
Countermeasures BasicCountermeasures BasicAct
Act• Building Standard Act• The Flood Protection• City Planning Act
Act (mandatory• Flood Protection Act
preparation/ delivery of• Sediment Disasterflood hazard maps)
Prevention Act• Disaster Relief Act

Systems• First-class/second-classrivers (integrated water
system)• Designated section
for ,minister’s
administration• Basic policy,
development plan

• Development control• Regional Plan for• Comprehensive flood
Disaster Prevention
management measures• Calamity danger district• Sediment disaster(special) — prone areas

Institutions• Ministry of Land,• Ministry of Land,• Ministry of Internal
Infrastructure andInfrastructure andAffairs andTransport (Development Transport
Communications
Bureau/Office)• Local government• Ministry of Land,• Local government(public works, urban
Infrastructure and(public works bureau)
design, architecture)
Transport• Japan Water Agency• City planning council• Local government• Councils on overall flood (disaster prevention
management
bureau)/ flood-fighting
corps• FRICS

Technology• Public works technology

Budgets• Special AccountBudgets for FloodControl (National)• Local government
budget22• Special AccountBudgets for FloodControl (National)• Budgets for City
Planning Projects• Local government
budgetModernization of Hydrological Services in Japan and Lessons for Developing Countries• Special AccountBudgets for FloodControl (National)• Local government
budgetof inundation and encouraging flood-proof building.
In Japan, the area of controlled development isclearly identified under the City Planning Act, anddisorderly development is controlled. In river basins
with serious flood protection issues arising fromrapid land development, a council consisting of rivermanagement authorities and local governments
is organized, under which comprehensive flood
management measures targeting the whole basin
are taken.

Figure 10 shows changes in the national flood control
budget, which includes hydrological services.1 Thissystem, in which hydrological service costs areincluded in the expense of flood control projects,
is reasonably in line with the characteristics ofhydrological services and is a practical means toensure necessary financial resources.

3.5 Evolution prompted by technology
development

To minimize the damage in case of inundation, it isnecessary to develop facilities that swiftly and reliably
inform residents of disasters and evacuation plans,
and that prepare and deliver flood hazard maps anddisaster prevention drills (based on prior estimation ofdamages). There must also be emergency measuresin place to deal with the rescue/relief of affected
residents and support for evacuees. Mayors are
responsible for securing the safety of residents, andthey work together with river management authorities
to reduce damage, provide hydrological services, andsupport efforts to deal with disasters.

Technological development in the observation of
rainfall, river water levels, and flow velocity has
progressed in response to users’ needs for better
observation accuracy and more user-friendliness.
In recent years, more advanced devices using radio
waves or ultrasound to observe flow velocity havebeen developed, such as acoustic Doppler current
profilers (ADCPs), which maximize the Doppler effectof ultrasound. Other recent developments include
technologies using closed-circuit television (CCTV)
images to observe river surface flow velocity or using
satellite images for flood forecasting.

Figure 10. Annual budget for flood risk reduction (or management) of Water and Disaster
Management Bureau (billion yen)

Billion yen

Flood Control Budget

2,500
2,000
1,500
1,000
500

1

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

0

It is difficult to precisely estimate the actual budget for hydrological services, as their associated costs are integrated in various budget lines.

Japan’s Hydrological Service Development Process and Related Knowledge, Experiences, and Lessons

23Technologies developed in different areas have also
been introduced to hydrological observation. One
example is radar technology, which was originallydeveloped for military purposes to locate airplanes.
This technology has been found very useful fordisaster management purposes because it is capableof observing the condition of raindrops over awidespread area. The rapid progress of information
technology has also contributed to disastermanagement by allowing large volumes of data to beprocessed and transmitted at a faster rate. Advanced
ICT technology has enabled in-depth analysis ofvoluminous data, production of more user-friendly
interfaces, and provision of information with handheld
devices.
A typical case in which a specific need accelerated
technological development is that of X-band MP
radar. In 2008, serious human damage resulted
from the Toga River flood in Kobe City, which wascaused by localized torrential rain. This incident
evidenced the necessity of technology capable ofmore detailed observation in a shorter period oftime complementing conventional C-band radar
network, which is useful to monitor larger scaleprecipitation events: i.e., X-band MP radar. Today, this
newly developed radar is in operation at 39 places
nationwide.
See Annex 2 for other examples of technologicaldevelopment.

habitable; thus large cities, including Tokyo, havedeveloped in the low-lying areas downstream of large
rivers, where inundation has occurred repeatedly.
At present, 51% of the population and 75% of thenational assets are concentrated on floodplains,which account for merely 10% of the national land.
The population density of the floodplains in Japan is
1,600 persons/km2, which is much higher than thatof other countries (Figure 11).
To protect people and assets from floods, thetraditional focus of river management authorities was
structural measures, such as construction of levees
and dams. Efforts to communicate flood risks to the
public were inadequate. This approach contributed
to a decline in awareness of flood risks among the
local residents because it gave them a false senseof safety, which resulted in an increasing number ofpeople living in areas subject to inundation. All thesetrends understandably contributed to a decrease in
the public’s overall coping capacity in case of a large
disaster (Figures 12 and 13, see page 26).
While the area of residential land experiencing
inundation has decreased through river management,
the amount of damage to general assets has not,because of the increase in vulnerable assets.
To address these situations, river management
authorities have shifted flood management policies toprovide residents with local risk information such as
inundation risk areas and inundation depths.

3.6 Challenges
Past flood management in Japan went throughnumerous successful and unsuccessful experiences
while always striving for improvement. The
modernization of hydrological services contributed tosolving some problems.
The following section presents past issues along withsolutions.
Declining coping capacity during disasters fromexcessive expectations for disaster prevention
structures
Japan mostly consists of steep mountainous areas,
with only a small percentage of the national land left

24

Confusion from disaster forecasting withuncertainty
When residents face an imminent disaster, it is themunicipal mayor’s responsibility to issue evacuation
orders and advisories in order to encourage safeand rapid evacuation, as defined by the Disaster
Countermeasures Basic Act. If an evacuation
advisory and order are issued prior to flooding—that
is, based on flood forecasting—this may substantiallyreduce disaster damage. However, forecastingalways entails a certain level of uncertainty, andthus disasters may not occur as forecasted. To
avoid evacuation advisories and orders ending in a
false alarm, they were often not issued until after

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

Figure 11. Population and assets concentrated in the inundation areas in Japan

䞉䞉䞉Areas lower than the water level during flood

䞉䞉䞉Other areas

Asset rate
Japan

About 䠓䠑䠂About 䠑䠌䠂Populaon rate
Area rate

About 䠍䠌䠂0%

10%

Populaon rate
England+Wales

30%

40%

50%

50%

60%

40%

50%

60%

70%

80%

90%

100%

90%

100%

About 䠕%Area rate

About 䠍䠌%
0%

USA

20%

10%

Populaon rate

20%

30%

40%

70%

80%

90%

100%

About 䠍䠌䠂Area rate

About 䠔%
0%

10%

20%

30%

60%

70%

80%

5.0

General asset flooded density

䠄Damaged amount of general assets
per inunda on area䠅
Inunda on surface areaof the residen al land

4.0

3.0

6,000

5,000

4,000
Damaged amount of
the general assets

3,000

2.0

2,000

1.0

1,000

0.0

Damaged amount of the general assets ( Cost as of Heisei 12)
Per inundation area 1ha,

Flooded surface area 䠄Unit: 10,000 ha)

6.01㻰㼍㼙㼍㼓㼑㼐㻌㼍㼙㼛㼡㼚㼠㻌㼛㼒㻌㼠㼔㼑㻌㼓㼑㼚㼑㼞㼍㼘㻌㼍㼟㼟㼑㼠㼟㻌䠄㼁㼚㼕㼠㻦㻌㻝㻜㻜㻌㼎㼕㼘㼘㼕㼛㼚㻌㼥㼑㼚䠅

Figure 12. Inundation area and damage amount of general assets per inundation area

0
83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10

Year

Japan’s Hydrological Service Development Process and Related Knowledge, Experiences, and Lessons

25

Figure 13. Number of disaster casualties in Japan

Number of dead and missing

Main disaster䠖Great East Japan earthquake(18,506)

Main disaster䠖Mikawa earthquake(2,306),
Makurazaki typhoon(3,756)
Main disaster䠖Nankai earthquake (1,443)
Main disaster䠖Kathleen typhoon (1,930)
Main disaster䠖Fukui earthquake (3,769)
Main disaster䠖Nanki heavy rain (1,124)
Main disaster䠖Toya Maru typhoon (1,761)

Main disaster䠖Kobe earthquake(6,437)

Main disaster䠖Ise Bay typhoon (5,098)

1945

1950

1955

1960

1965

1970

1975

Year

a disaster had actually occurred. In fact, between
1961, when the Disaster Countermeasures Basic Act
was enacted, and 2004, no evacuation advisories
and orders were issued before levees breached or
sediment disasters occurred.
However, for residents to understand flood risk
and take appropriate evacuation action, they needto make the most use of information from flood
forecasting. Acknowledging that forecastingalways contains a certain level of uncertainty, rivermanagement authorities have sought to share
forecasting information with local municipalities at
early stages and have encouraged municipalities
to use the information for disaster management.
They are also working to improve how to present
information containing uncertainty to residents sothat it is not misunderstood.
In September 2015, record-breaking heavy rainfall hit
parts of the Kanto and Tohoku regions, particularly
over the upstream area of the Kinu River, which
breached a part of the levee in Joso City, Ibaraki

26

1980

1985

1990

1995

2000

2005

2010

Assessment Report on Disaster Risk Reducon,2014, The Cabinet Office

Prefecture. The flood caused serious damage,inundating about 40 km2 of land, submerging manybuildings, including the Joso City Office, and leaving
two dead and many injured. However, it should be
noted that during the disaster, an MLIT river officein charge of the management of the Kinu River, incoordination with JMA, provided Joso City withinformation on flood danger and with inundation risk
area maps. This was part of the effort to share anduse information with careful consideration of theuncertainty it contains. As the information was not
utilized by the municipal government for reducing
flood damages, MLIT initiated a basic policy torebuild a flood-disaster-conscious-society, in whichadministrators, the public and companies share theknowledge of and preparedness for flood risks.
Difficulty in taking responsibility for actions basedon information with uncertainty
Since the construction of structures such as levees
takes a long time, floods may occur during theconstruction. Moreover, even after structures arecompleted as planned, there is still a possibility ofModernization of Hydrological Services in Japan and Lessons for Developing Countries

floods. Because of that, governments and citizens
should understand that they need to prepare forfloods to minimize damage, and in the past, rivermanagement authorities usually provided information
related to flooding.
As time went by, the primary focus was shifted tostructural measures such as dams and levees toprevent floods, and at the same time many lawsuits
were filed by disaster victims seeking compensation
for damage. As a result, river management authorities
started avoiding the provision of flood information,
which often seemed to create confusion about who
should take responsibility for such information,and they focused their attention only on rivermanagement, where responsibilities were clearly
understood.
Then, a further shift in flood management policy
moved away from disaster control, which means
preventing disasters from occurring completely, todisaster mitigation, which means reducing disasterdamage as much as possible. After 2005, when
the revision of the Flood Protection Act mandated
the distribution of hazard maps, river management
authorities resumed the active provision of flood
information. However, more efforts are still needed
to help citizens translate flood information—suchas inundation risk areas and inundation depths—toappropriate evacuation actions in case of flood.

In 2004, when flood disasters occurred in many partsof Japan, the Cabinet Office developed guidelines
for the preparation of a manual on making proper
decisions about issuing evacuation orders andadvisories, with the goal of encouraging local mayors
to issue them proactively. The guidelines did notwork as expected, however; mayors started issuing
evacuation orders that may not have been necessary.
This occurred in 2008, when Okazaki City of Aichi
Prefecture issued an evacuation advisory to its
entire population in response to localized torrential
rain. It occurred again in 2011, when Nagoya City ofthe same prefecture issued an evacuation advisory
to its population of more than one million people.
Consequently, the public began to wonder if they
really had to evacuate and to question the reliability ofthe orders.
Because of these situations, efforts have been madeto develop easy-to-understand criteria for mayors
to use in deciding when to issue evacuation orders
and advisories. In addition, based on lessons learned
from the 2015 Kanto-Tohoku heavy rainfall, in whichhydrological information did not lead to successful
evacuation of local residents, more effective methods
for providing information are being sought.

Linking flood information with disaster mitigation is
also an important issue for developing countries.
Difficulty in deciding the timing of evacuation orders
and advisories
Deciding when to issue an evacuation order has beena serious challenge for local governments. Not only
must they confront the uncertainty often containedin forecasting information, but they are sometimes
not very clear about what an evacuation order andadvisory really mean. In other cases, they have little
information about incoming hazards and the statusof levees and other structures.

Japan’s Hydrological Service Development Process and Related Knowledge, Experiences, and Lessons27

4. Organizations Related to Japan’s Hydrological
Services and their Relationships

4.1 Changes in governmental and otherorganizations
Changes in governmental organizations (up to 2000)
Japan saw the modernization of governmental
systems after the Meiji Restoration in 1868. The
Ministry of Home Affairs was assigned responsibility
for river management and flood control, and started
collecting and organizing hydrological data as part ofits role.
After World War II, the Home Ministry was abolishedand its functions were distributed among four
ministries, including the Construction Ministry,
which took over the duties of river management.
DRM for farmland and port facilities was assigned
to the Ministry of Agriculture, Forestry and Fisheries
and to the Ministry of Transport, respectively. In
addition, the Ministry of Transport, the Ministry ofAgriculture, JMA, the National Police Agency, the Fire
Defense Agency, and the Defense Agency all had an
important part in emergency response. Since several
agencies and ministries were involved in DRM, theNational Land Agency was given the responsibility for
coordinating the effort.
Incorporation of the Meteorological Agency and theRiver Bureau (Establishment of MLIT)
When the governmental agencies and ministries wererestructured in 2001, the River Bureau and the JMA,
which had been under separate ministries since the
Meiji era, were incorporated into MLIT. Long before
this incorporation, however, those two agencies had
issued flood forecasts jointly, and had exchanged
and shared real-time hydrological and meteorologicalinformation observed by each institution. They had

28

also kept close communication through personnel
exchange. The integration has made the cooperationeven closer, and it has increased opportunities forbetter aligning policy planning and implementation
as well as jointly responding to disasters under thecoordination of the Disaster Prevention Center.
Although the River Bureau and JMA seem to be
conducting similar observations that could be viewed
as redundant in some cases, the content of theirobservations is in fact different. The observations of
the former mainly focus on runoff into rivers, and thedata collected by the latter are primarily related toweather forecasting. For example, the radars of theRiver Bureau emit radio waves from high altitudes
with low angles for capturing rainfall conditions
near the ground; the radars of the JMA emit radio
waves from low altitudes with high angles. Becauseof the difference in data type, the integration of datacollected by each organization is not always simple,
but the two institutions complement each other andwork in close corporation.
Establishment of the Cabinet Office
After the major governmental restructuring in 2001,
planning of important political issues in Japan—such as economic policy and disaster management
policy—was to be conducted under the Prime
Minister, and the Cabinet Office was established as
the secretariat. With respect to disaster management
policies, the minister for disaster management
was assigned to the Cabinet Office, which led
disaster management policy planning, and theCentral Disaster Prevention Council (chaired by thePrime Minister) was to make decisions. While theDisaster Prevention Bureau of the National Land

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

Agency had coordinated related ministries andagencies previously, the disaster prevention sectionof the Cabinet Office, under the direction of thePrime Minister, now was responsible not only for
coordinating related ministries and agencies, but also
for planning the disaster management policies of
the whole nation. These changes signaled dramatic
progress in comprehensive disaster management
policies based on strong coordination. Under thisframework, collaboration between the River Bureau
and JMA progressed, and various measures ofdisaster management, such as early warning
information delivery on multi-hazard, advanced.
Establishment of Water and Disaster Management
BureauIn 2011, when MLIT was reorganized, the Water andDisaster Management Bureau was established bymerging the Water Resources Department of Landand Water Resources Bureau, the Sewerage Works
Department of City and Regional Development
Bureau and the River Bureau. This integration
improved coordination of various measures related
to water, such as preparation of hazard maps dealing
comprehensively with both floodwater from rivers
and inundation caused by lack of drainage capacity inurban areas.

4.2 Role-sharing and cooperation
between the government and citizens
Self-help, mutual support, and public assistance
To minimize disaster damage, three components
are equally important and need to function
effectively: public assistance (in which governments
provide assistance before a disaster and for crisis
management), self-help (in which people protect
themselves), and mutual support (in which people
support one another at the community level). In
rescue operations, for instance, public assistance
may be necessary if heavy machinery is needed,
but in other cases self-help and mutual support
work more effectively. During the Great HanshinAwaji Earthquake, for example, 85% of people
were evacuated by practicing self-help and mutual
support, which is much more than were rescued ingovernmental efforts.

The three components are also important forwater-related disasters. Public assistance provides
residents with hazard maps and hydrologicalinformation during disasters to encourage them totake appropriate evacuation actions. Residents are
expected to practice self-help and mutual support;
residents and communities receive the information,assess their own and surrounding conditions
properly, and take necessary action to reduce
damages.
Flood fighting in close cooperation with local
communities
A good example of mutual support in Japan can befound in cooperative efforts by local residents to fightfloods. When a local river floods, people cooperate inpiling up sand bags to prevent inundation, warningneighbors about coming dangers, and encouraging
others to evacuate.
The context for this community-based flood
mitigation is the legal framework established in1949. Municipal governments play a leading rolein assisting the public in this effort, while rivermanagement authorities also support them byproviding hydrological information and materials andequipment for flood fighting.
Hydrological observation by local residents
In the 1940s, when telemeter systems were still
rare, MLIT (the Construction Ministry at that time)delegated hydrological observation to local residents
living near an observation station. These cooperative
observers helped to create a substantial archive ofhydrological data by observing river water levels, aswell as rainfall and groundwater, at the same timeand locations every day.
The widespread use of telemeter systems gradually
decreased the importance of cooperative observers
in hydrological observation. While the system ofcooperative observers is no longer in effect, thesystem was helpful in enhancing the involvement oflocal residents in river management.

Organizations Related to Japan’s Hydrological Services and Their Relationships

29

4.3 The involvement of the private
sector
The private sector has contributed a great deal tothe development of observation instruments andanalytical technology used in relation to hydrologicaldata.
In Japan, imported tide gauges were used to observe
river water levels. After the collapse of Japanesecurrency that followed the Second World War, thedevelopment of domestic automatic water-level
gauges started. In 1962, under a collaboration of the
public and private sector, the first domestic automaticwater-level gauge (Suiken Type No.62) was finallydeveloped and replaced the costly imported gauges.
This was a milestone for the widespread use ofwater-level gauges that followed.
The public-private partnerships also played a largepart in the dramatic progress in ICT as well as theenhancement of information systems and thedevelopment of rainfall radar (see sections 3–5).
Moreover, the public sector, research institutes, andprivate consulting firms have been cooperating in thedevelopment of analysis technology for hydrologicaldata.

4.4 Government’s relationship withmass media

public relations vehicles, and the Internet. The
public sector and the mass media need to closelycooperate in providing necessary information in orderto encourage the public to take proper action foravoiding and reducing disaster damage.
In normal times, the mass media should be a reporting
entity that is independent from the administration,and it usually has an objective attitude towards
governments. In an emergency, however, those two
sectors have cooperated to make sure that people
receive necessary disaster-related information.
Cooperation agreement between the mass media
and the public sector
The following agreements have been made to secure
the cooperative relationship between the mass media
and the public sector.
• Agreement on broadcasting and reporting
between prefectural governments and themass media
This agreement is based on the Disaster
Prevention Basic Act. Prefectural governors andbroadcasting stations and news agencies haveagreed that the governors may ask for important
information (such as warnings and evacuation
orders and advisories) to be broadcast andreported during disasters.
• Agreement on the provision of data and footage
between MLIT, etc. and the mass media
For the purpose of flood damage prevention
and support for safe evacuation, MLIT andother relevant agencies have agreed to provide
data on ground rainfall, data on water levels,
radar rainfall data, and footage of rivers forbroadcasting stations to use at their disposal.

Role of the mass media during large disasters
In Japan, the mass media (such as TV stations) plays
an important role in communicating information to
the public during disasters; because they are easily
accessible, they offer residents a useful way to get
an overall picture of the situation. In particular, theJapan Broadcasting Corporation (NHK) is the legallydesignated public agency for DRM and is expected toprovide information in case of a disaster.

4.5 Establishment of FRICS

Information provision organized by the public sector
is also important and is a more appropriate way
to provide area-specific information; the public
sector disseminates information through disastermanagement radio communications (outdoor
publicity loudspeakers installed in neighborhoods),

Background of the establishment of FRICS
In the early 1980s, when public awareness of flood
damage started rising and river use became frequentand diversified, the need for hydrological information
grew, not only during floods and disasters but also innormal periods. In 1982, the Nagasaki flood disaster

30

Modernization of Hydrological Services in Japan and Lessons for Developing Countriesoccurred (figure 14), and it was found that thedamage could have been greatly reduced if residents
had been provided with hydrological information.
This incident further accelerated the demand forhydrological information from municipalities, themass media and the general public during floods.
At that time, the national government also providedhydrological information to some local governments
separately. However, to avoid confusion, there was anurgent need for a system that allowed information to
be standardized and provided to many users.
Reluctance of the private sector to be involved inhydrological services
Meteorological information is necessary not only
during disasters but also in everyday life, and it isin particularly high demand by the mass media for
their daily broadcasting. In addition, people involvedin agriculture or in organizing events also needmeteorological information. The demand for thisinformation is huge, constant, and from a wide varietyof perspectives.

However, it is still true that the demand forhydrological information is far less in normal
periods than during disasters. Power generation
and agricultural facilities take, store, and use alarge volume of river water, and these sectors
have individual networks with river management
authorities to obtain necessary information.
Moreover, the river regime usually has little effecton river water intake in the case of small-scale
irrigation, where the need for information on day-today hydrological conditions is not necessarily large.
Thus few sectors have been willing to pay the costof receiving information. In turn, private corporations
have avoided involvement in hydrological services.
At present, the Foundation of River & Basin Integrated
Communication (FRICS) runs a business to deliver
numerical data on hydrological conditions. Although
there are some cases in which weather informationcompanies receive and process data from FRICS anddeliver secondary data to users, the need for dailyhydrological services at present is not large.

Figure 14. Nagasaki disaster in 1982

Organizations Related to Japan’s Hydrological Services and Their Relationships

31

Establishment of FRICS
On the other hand, to meet the demand for accurate
and timely information during disasters, a systemneeds to be designed that continues operations,
including monitoring data, on a 24/7 basis. To
provide information that helps to avoid and reduce
disaster damage, it is important not only to provide
information in a simple format but also to indicate
what kind of actions are necessary given the statusof a disaster. To secure human resources is anotherimportant priority; experts with practical knowledge
and skill in river management and DRM are needed
to handle information properly. Although national
government officials recognized the significanceof such institutional arrangements, creating a newagency for this role was extremely difficult, as thegovernment of the time was working to downsize
itself.
Despite these difficulties, FRICS was established,
October 1, 1985, as a collaborative effort. In addition
to the subsidy from the government, funding comesof Land, Infrastructure and Transport
Figure 15.Ministry
Flowof Roadriver
information(RiverBureau,Bureau,Meteorological Agency)from both the public and private sectors: contributors
include prefectures and ordinance-designatedcities, the mass media such as NHK, manufacturersof devices and sensors, banks, the Japan Dam
Foundation, and the Japan Civil Engineering
Association.
The role of FRICS is to provide information
standardized for the convenience of users, totransmit a large volume of information to numerous
users (by means of its large hardware), and tomonitor information 24/7, all year round. In addition,
it is equipped with experts who can respond to users’
needs, handle troubles appropriately, and constantly
improve the system in response to various needs.
With the establishment of FRICS, the institutionalarrangements were in place to facilitate delivery of
quality hydrological information, mainly observed by
the national government (Figures 15, 16, and 17).

㻲㻾㻵㻯㻿
Data collection node

FRICS

RaderofRain䚷
Ministry
Land, Infrastructure and Transport
gauges(River Bureau, Road Bureau, Meteorological Agency)㻲㻾㻵㻯㻿Governmental ministries andMunicipalities
agencies etc.

Data collection node

Telemeter
Rader
Rain䚷
stations
gaugesPrefectural government䠣㻵㼚㼠㼑㼞㼚㼑㼠

Telemeter
stations

river administrators

Telemeter
stations

river administrators

Prefectural government

Telemeter
stations

32

GeneralpublicMunicipalities

river administrators

General publicMedia㻵㼚㼠㼑㼞㼚㼑㼠

river administrators

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

MediaFigure 16. Provision of river information

Rainfall/Water Level/Flow Rate
Indicates relation between water level of the river etc. or standard
water level, and level of residential area

Radar rainfall

Planned Maximum water
volumeItem

Rainfalldistribution,
rainfallintensity
distribution
can be viewed
in time series

Sustainable waterlevel of ﬂood
ﬁghting corps

Standard

Flood warning
water level

Evacuation waterlevel

Flood hazard water
level

Planned high water
level

Level
Current
value

Cumulative rainfall

RainfallRainfallFlow Rate
Flow volume

Water level

Flood warning
Flood advisory

Warning information
Indicates flood
forecast andflood
prevention
warning, etc.

Ashikaga

Water Level

Stand-by water level for
ﬂood ﬁghting corps

Watarase River

Flood warning waterlevel

Evacuation water level

Planned high waterlevel

Flood hazard water level

List of water level above thresholds
Lists water level observation stations that indicate a level above thethresholds, such as flood hazard level, etc.
Ora-choObservation station
name

Tatebayashi

Ashinoko Lake

Chiyoda-cho

Meiwa-choWatersystemRiver name

Water
level

Time ofStand-by forobservation
ﬂood ﬁghting
corpsStandard water level (m)Floodwarning

Location
Evacuation

Flood hazard

Kanto, others Ashinoko lake
Yodo River

Mt. Makio

Management

Municipality

Uji River

Left bank

National river

Figure 17. Monthly accesses of river information

Page View/Month180,000,000

2002 03

04

05

06

07

08

09

10

11

12

13

14

䕔Xband䕔River Office䕔Municipality
䕔Public 䠬䠟䕔Public Mobile

Organizations Related to Japan’s Hydrological Services and Their Relationships

33

Role of FRICS
In addition to providing hydrological information,
FRICS conducts various projects and research andworks to promote technological development usinghydrological information. Specifically, it engages in
the following:• Collection, processing, analysis, and provisionof river and basin information, as well as
research and development to improve those
activities• Development and management of databases
on hydrology and water quality• Technological development of radar rain
gauges• Development of flood forecasting systems
using hydrological data
• Development of crisis management technology
using hydrological data

4.6 User groups
Presently, many types of hydrological information
related to DRM are widely available for the generalpublic. However, organizations especially involved in
DRM are given identification and provided with moredetailed information.
The following section describes the organizations
that utilize hydrological information and their
purposes.
Organizations that manage rivers and structures
such as dams and water gates
Information is used for operating and managing
structures such as dams and water gates, monitoring
unusual events during floods, and forecasting
inundation.
Organizations in this category are:
• MLIT (Water and Disaster Management
Bureau)• Prefectural government (Construction
Department)• Japan Water Agency• Development of hazard mapping technology• Distribution of numerical information• Development of hydrological information
systems for developing countries• Training of interns from developing countries
on hydrological information
FRICS constantly improves systems that provide
hydrological information for the sake of users. In
particular, the new information provision systemcurrently under development will be capable ofproviding information on ground rainfall, waterlevels, radar rainfall, and inundation risk, as well as
hazard maps and CCTV images of rivers, in a waythat allows users to easily understand contents
and structures. It will also realize more user-friendly
operation and require no manuals. Finally, it will
enable users to view all kinds of information usinga smartphone. This revolutionary system has been
available since April 2016.

34

Local governments
Local governments are responsible for securing thesafety of residents: when a disaster is imminent or
actually occurs, they are required to issue evacuation
information (including evacuation orders andadvisories), set up and manage shelters, and direct
efforts to fight floods. Hydrological information isessential for local governments to make decisions onthese actions.
Organizations in this category are• Cities• Towns• Villages

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

Organizations that support disaster management
efforts of local governments
In case of a disaster, prefectural governments, incooperation with local governments, have to engage
in response efforts. When a large-scale disasteroccurs, the Self-Defense Force will be mobilized at
the request of a prefecture or local government. The
Fire Defense Agency of the Ministry of Internal Affairs
and Communications (which holds jurisdiction overthe firefighting efforts by prefectural and municipal
governments), the National Police Agency (which
oversees prefectural police), and the Self-Defense
Force of the Ministry of Defense are also involved indisaster response actions; they work in cooperation
with each other, using hydrological information tocapture the status of a flood disaster quickly andaccurately.
Organizations in this category are• Prefectural governments• Ministry of Internal Affairs andCommunications (Fire Defense Agency)• National Police Agency• Ministry of Defense (Self-Defense Force)
Government headquarters for disaster control
In Japan, the government headquarters for disaster
control, headed by the Prime Minister or the minister
responsible for disaster control, will be activatedin case of a large-scale disaster. The members
are required to share hydrological information,
understand the disaster situations accurately, andconduct risk management, rescue, relief, restoration,and rehabilitation immediately.
Organizations in this category are• Central government ministries and agencies• Japanese Red Cross Society• Bank of Japan• NHK• Nippon Telegraph and Telephone Corporation

Organizations that operate lifeline utilities andtraffic infrastructure
Lifeline utilities (e.g., electric power, gas) andtraffic infrastructure (e.g., expressway, railway) areindispensable for people’s everyday lives. Although
the first priority is ensuring safety, they also should
be maintained as carefully as possible to avoid
interruption, and should be restored as soon as
possible even when interrupted. Organizations
that operate these businesses utilize hydrologicalinformation to manage facilities appropriately when adisaster is imminent or actually occurs, and to restore
them when they are damaged.
Organizations in this category are• Communications companies• Electric power companies• Gas companies• Japan Post
• Japan Railways• Airport companies• Expressway companies
Mass MediaTo encourage residents to take appropriate actions
when a disaster is imminent or actually occurs,
information should be delivered to as many people aspossible. Currently in Japan, the mass media, suchas TV, are dominant in information delivery. NHK andother broadcasting and news-reporting companies
should make efforts to obtain hydrologicalinformation from authorities and provide it for thegeneral public.
Organizations in this category are• NHK• Private broadcasting stations

Organizations Related to Japan’s Hydrological Services and Their Relationships

35

5. Application of Japan’s Knowledge, Experience,and Lessons to International Cooperation
Projects Relating to Hydrological Services

5.1 Technical cooperation projects up
to the present2
The Republic of Korea
In the Republic of Korea, the flood forecasting/warning system in the Hangang River, with a basin
area of 26,200 km2, was practically completed in1974 with JICA’s grant aid. The system received
several adjustments in the operational stage
thereafter. But in the system’s actual operation, theconsistency between the calculated estimation
value and the actual measurement value was
not satisfactory, and an overall and fundamental
reexamination of the system and model became
necessary. Responding to a request for technicalcooperation from the government of the Republic ofKorea in 1980, the Japanese government dispatcheda flood forecasting expert in February 1981and ahydrological expert in November 1981. The technicalcooperation project was carried out through actual
flood forecasting/warning operations and involved (i)an overall examination on the issues and measures toimprove the flood forecasting system/model for the
Hangang River; (ii) an examination of specific itemsin the forecasting calculation model improvement; (iii)
an examination of the draft comprehensive plan for
the Hangang River flood forecasting/warning system,with the goal of expanding the system in the future;and (iv) deliberation about dam operation procedures
and the flood forecasting calculation model

improvement, as well as the low-water-flow control
policy for the Hangang River (taking the completion of
the Chungju Dam into consideration).
Since 1981, the Construction Department of the
Republic of Korea and the Ministry of Constructionof Japan have exchanged information on rivertechnology as part of the Japan-Korea TechnicalCooperation Meeting on River and Water Resource
Development. This project helped to improve
Korean technology relating to flood forecasting/warning. Through capacity building and training oftechnical operators/engineers and relevant facility
development, the country reached a level at which it
can itself develop systems of flood forecasting.
The Philippines
The Pampanga River, one of the most important
rivers in the Philippines, is located near the capital
city of Manila and contains a large grain belt in thedownstream area along a well-developed floodplain.
In September 1973, with grant aid from the Japanese
government, the first flood forecasting system in thePhilippines was established in the Pampanga Riverbasin. Notably, the system played a crucial role at thetime of the catastrophic flood in May 1976, saving
many people’s lives and property from the disaster.
In 1981, a general rehabilitation of the system wascarried out with grant aid.

2 Technical cooperation is an all-embracing general term used to describe JICA’s practical assistance to developing countries. Depending on thespecific projects, technical assistance can include the dispatch of JICA experts, the training of local officials for “capacity development,” or the
supply of equipment or financial assistance. Technical cooperation is one of JICA’s three major areas of development assistance, the others
being provision of grant aid and low-cost yen loans.

36

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

Based on the success of this flood forecasting
system, the government of the Philippines asked
the Japanese government for a plan to expand thesystem into the Agno in middle Luzon, the Bicol insouth Luzon, and the Cagayan in north Luzon. This
expansion was completed in May 1982.
The government of the Philippines, aiming at zerodisaster damage, set out to reinforce disastermitigation organizations and to enhance the flood
forecasting/warning system in the mid-term national
development plan for the period 2004–2010.
In the flood forecasting/warning systems of the
Pampanga River and the Agno River, major rivers
in Luzon, the observation function was ineffective
because the observation/monitoring apparatus had
deteriorated, and because communication between
the observation stations and the central monitoring
center was not well-functioning. This problem wasconsidered the cause of increasing damages.
The Philippine government requested grant aid forprompt and appropriate improvement of the system’sobservation/information transmission functions
under the Project for Improvement Plan of Flood
Forecasting and Warning System in the Pampanga
and Agno River Basins. Responding to the request,
in 2007–2008 the Japanese government provided
funds for improving the flood forecasting and warning
system, communication networks, and observation
stations in the Pampanga and Agno River basins, aswell as for maintaining the monitoring apparatus/
equipment in the central monitoring center and in therelated institutions for disaster management.
Thus 30 years after its development began, the flood
forecasting/warning system of the Philippines is still
not independent.
The People’s Republic of China
In China, flood prevention and damage reduction are
considered important issues, as flood damages havea serious influence on the national economy. Thisis because China’s population, cultivated land, andmain roads are concentrated in downstream basin
areas of large rivers. However, the command andcontrol system operated by the general headquartersof China’s national institution for water disasterprevention was growing old by the 1980s, making
prompt and effective response to floods difficult. In
1990, the Chinese government asked Japan, which
had advanced technologies and expertise in flood
forecasting, to establish an effective automatic
system for water disaster prevention, and to carryout a technical cooperation project aimed at training
flood forecasters.
Through this cooperation, the following outcomes
were obtained:• The “central water disaster prevention
information system” constructed by thisproject was utilized for flood status monitoring;at a time of significant nationwide floods,
including the Chang Jiang River flood (March–
September 1998), it carried out automatedcollection, transmission, processing, anddisplay of river information. It contributed toadequate water disaster prevention througha high-quality information system for thegeneral headquarters of the National Command
Institution for Water Disaster Prevention.3• The “river information transmission system in
the Zhangweinan Canal basin area”
constructed by this project4 allowed reliabletransmission of river information such as
rainfall, river discharge, water level, etc., even in
bad weather, to the Zhangweinan Canal control
bureau, and facilitated communication among
respective institutions/organizations—and
this—including at the time of historic flooding inAugust 1996. It thus contributed to adequate
water disaster response by the Zhangweinan
Canal control bureau.

3 According to the estimation by the Chinese, in 1998 the project’s flood information and forecasting system were part of flood prevention/
countermeasures that reduced China’s costs by 80 billion yuan.
4 Under this project, manually operated data transmission using a wired communication line was transformed to an automated telemeter systemusing radio transmission.

Application of Japan’s Knowledge, Experience, and Lessons to International Cooperation Projects Relating to Hydrological Services37• The “forecast result selection system,” which
was the first practical application of this kindin China, used multiple models to solve difficult
issues entailed in flood forecasting in the semiarid region of northern China. Technologies toaddress similar issues in other basin areas werealso transferred.
Based on the experience of this project, China isdeveloping its flood forecasting/warning system
nationally.
Pakistan
The Indus River basin of Pakistan suffers fromflooding almost annually during the monsoon
season (from mid-June through late September).
The large-scale flood in 2010 affected about 20
million people and claimed the lives of about 2,000.
Flood forecasting and warning systems, thoughinstalled in the basins of some tributaries of theIndus River, were not in place over its upper reaches
or in the Kabul River basin, where much of thedamage occurred during the 2010 flood. The lack ofawareness about floods and crisis management wasalso seen as an issue for improvement.
In response, a project led by UNESCO and fundedby the Japan International Cooperation Agency,
entitled “Strategic Strengthening of Flood Warning
and Management Capacity of Pakistan,” wasimplemented from 2011 to 2014. It was executed
as a comprehensive flood management project: it
introduced flood forecasting and warning systems
and hazard mapping, developed an informationsharing platform, and provided capacity developmenttraining, all as part of a collective effort involving
Pakistan’s national ministries and agencies, theJapan Aerospace Exploration Agency (JAXA), andthe International Centre for Water Hazard and Risk
Management (ICHARM). Pakistani involvement camefrom organizations in diverse areas ranging fromnationwide disaster prevention to hydrometeorology,
such as the Pakistan Meteorological Department(PMD) and the Water and Power Development
Authority (WAPDA).
As a contribution to the introduction of flood

38

forecasting and warning systems and hazard
mapping, ICHARM led the development of a systemcalled Indus-IFAS for a wide area extending from theupper to lower reaches of the Indus River. The system
couples two key technologies developed by ICHARM:
the Integrated Flood Analysis System (IFAS) and theRainfall-Runoff-Inundation (RRI) model.
Capacity development training was provided
through the master’s program that ICHARM offers
in collaboration with the National Graduate Institutefor Policy Studies (GRIPS) of Japan. Six engineers
in their 20s to late 30s were sent by the Pakistani
government to study in this program, and they havesince been in charge of the operation of Indus-IFAS.
In addition, a total of 11 governmental officers
participated in a 10-day training workshop in 2012
and 2013.
The quality of this project has been assured. An external
evaluation committee consisting of experienced
experts from home and abroad was set up andcarried out academic and technological evaluationof the project. A press center was also establishedto provide the public with forecasting outputs andaccurate hydrometeorological information. The press
center remains in operation today.
Following the successful implementation of thisproject, Phase 2 has been initiated. This phaseincludes installation of Indus-IFAS for Indus’
tributaries, as well as technical instruction for the
Pakistani government on proper procedures forcollecting local data.

5.2 Lessons learned from past technicalcooperation projects
The Korean economy and Chinese economy have
rapidly expanded in the past few decades, and it has
been possible to secure the budget for developing
and maintaining flood forecasting systems as
measures for damage reduction. On the other hand,
the Philippines is prone to various kinds of natural
hazards, and the scale of disaster damages is large
relative to its national economic power. Disasters
are hindrances to economic development: economic
growth in the Philippines has not been rapid. This

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

may have been the reason that sufficient budget
was not prepared for maintaining flood forecasting
systems.
In Japan, the organization that manages rivers,
including construction works, provides hydrologic
services including hydrological observation and flood
forecasting, and this arrangement also exists in the
Republic of Korea (Ministry of Construction) and
the People’s Republic of China (Ministry of Water
Resources). The flood forecasting projects describedabove were received by the Ministry of Constructionin Korea and the Ministry of Water Resources in
China. Generally speaking, nonstructural measures
such as flood forecasting are relatively less costly
than structural measures. In many cases, even apart of the budget necessary for the latter would be
sufficient for developing a flood forecasting system.
Thus flood forecasting systems were properly
recognized in these countries as disaster prevention
measures, and the necessary budget was secured.
On the other hand, in many developing countries,hydrological observations and analysis are carriedout by organizations that do not manage rivers.
In such cases, even if related organizations
collaborate, the changing needs of management
organizations that actually use the observed data
may not be flexibly reflected in the observations.
River management in the Philippines was under
the jurisdiction of the Ministry of Public Works andHighways, and the aforementioned flood forecasting
project was received by the Philippine Meteorological
Agency. This might be one of the reasons that flood
forecasting in the Philippines was not properly
budgeted, and why the system was insufficiently
maintained in the past. If flood forecasting had been
considered an indispensable tool of DRM by the
responsible authority, it is more likely to have beensustainable in terms of budget and human resources.
While the example of Pakistan is rather recent,and cannot be considered in the same bracket
as the three other countries indicated above, thesustainability of the Pakistan project is expected,
given that Pakistan’s different national ministries
and agencies are involved, and that a press centerto provide the public with forecasting outputs andinformation is utilized by them.
How the flood forecasting system is used is ofimportance. Unless its social significance, such as itsrole in reducing damage, is clearly identified, it will bedifficult to persuade the country’s finance authority tosecure the necessary budget.

5.3 Case study of disaster managementin Thailand’s 2011 floods
At the request of the Thai government (May 2012),
JICA contracted with FRICS to develop a flood
forecasting system, which emerged as a major
need after the 2011 flood in the Chao Phraya River.
A prototype was developed in September 2012.
From the early stage of prototype design through its
application, Thai government officials were involvedin the project through workshops and technicalgroup meetings. Officials of different governmentorganizations, interested companies, and academics
were invited to register as monitors who were allowed
to access the information through the Internet.
This hydrological service system was developed fromusers’ perspective. Prior to designing the system,
multiple questionnaire surveys were conducted fora variety of respondents, including affected people,
NGOs, mass media, academia, and governmentorganizations. The system was developed toprioritize end-users’ needs over the indiscriminate
use of available data. Discussions were then held
to determine what systems were necessary to fulfill
these needs, followed by selection of data to feed into
the system.
The developed system was equipped with the
Runoff-Rainfall-Inundation model to forecast waterlevels, flow rates, and inundation areas using
observed data (rainfall, water levels, discharges) andmeteorological forecasting data from Thailand’s
Royal Irrigation Department (RID) and the Thai
Meteorological Department. It was also designed toforecast highly accurate inundation areas by using
LiDAR data and detailed geographic data obtained
after calibrating GISTDA (Geo-Informatics and Space

Application of Japan’s Knowledge, Experience, and Lessons to International Cooperation Projects Relating to Hydrological Services

39

Technology Development Agency) satellite images of
the inundation. Meteorological, satellite, and rivermanagement agencies collaborated closely in thiseffort.
In addition, the overall vision of Thailand’shydrological services and the role of the project
therein were defined clearly. The Basic Plan of FloodManagement Information System of Thailand wasformulated with the following aims:• Collect and sort views and ideas on
information systems to be constructed andoperated for residents and the government,
and designed to take effective action
immediately before and during disasters and in
the restoration stage.
• Stress the importance of understanding
disaster-related information even in normal
times, which will eventually lead to proper
actions in case of disaster.
• Focus not on the convenience of information
senders but the perceptions of information
receivers, and on how to ensure that the senders

provide information effectively to the receivers
such as residents and government organizations.
• Understand the needs and situation ofThailand accurately, and develop practicalplans in consideration of the differencesin knowledge, experience, and technology
between Thailand and Japan, both of whichsuffer from frequent natural disasters.
• Introduce effective new technologies bybuilding on existing observation and otherfacilities in Thailand, as well as informationcollection/transfer centers, analysis systemsof various organizations, and forecasting/warning systems.
• Present proposals that are not abstract but
specific and ready for the Thai government to
put into practice.
• Formulate plans that the Thai government canuse in planning various future projects.
System operation, information utilization, and otherrelated activities were strategically conducted to

Figure 18. Thai official happy with the updated flood management system

40

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

publicize the system in cooperation with the mass
media. In some of the workshops that were held,
Thai government officials, not project consultants,
explained the system.
The responsibilities for the system and its operation
were handed over to RID in September 2013. After thesystem’s operation and performance were evaluated,a follow-up project was planned to achieve thefollowing goals:• Improve and update models, based on
forecasting performance evaluations.
• Ensure effective and stable operation of the
updated system.

Good practices:• G1: The type of observation device is one of
the issues we need to address. Devices thatare locally available and easy to maintainworked well when used in observation forforecasting and warning for evacuation.
• G2: International experts were invited to join
the project team to watch the project for thetechnical level and overall progress.
• G3: Long-term training for capacity
development was also provided with thetechnical assistance.
Lessons learned:• Improve the water management simulator
and increase the understanding of operation
techniques and functions.
During the follow-up workshop, system operators
were given on-the-job training to learn how to
operate the updated system effectively and stably.
The system stopped in mid-December 2014 due
to a hardware breakdown. It took eight months tofind out the cause of the trouble and replace themalfunctioning parts, and another month to feed
accurate observation data and restart the system.
With the advice of the follow-up team, which was
remotely monitoring the system, Thai operators wereable to reboot the system successfully.

5.4 Issues for sustainable use of past
project achievements
Information was gathered on good practices andlessons learned from past technical assistanceprojects for developing countries. A questionnaire
was developed that asked for information about aid
providers, the titles and contents of projects, projects’
advantages and disadvantages (along with thereasons for each), and additional comments if any. The
survey included projects implemented in Bangladesh,
El Salvador, Guatemala, Kenya, Laos, Pakistan, andCentral and South America. The following commentson good practices and lessons learned are taken fromthe questionnaire. See Annex 1 for details.

• L1: Projects should be designed not as a onetime deal but as something that will lead us
to have different perspectives and plan future
projects.
• L2: Some projects use knowledge and skill
that are too advanced for aid recipients tounderstand. In such cases, it would be more
effective if they were implemented withtechnical training for the recipients.
• L3: The type of observation device is one of
the issues we need to address. Devices thatare locally available and easy to maintain may
be good enough for forecasting and warningfor evacuation, but may not be so effective
when it comes to collecting long-term data
because they are not designed to collectquality-assured data.
• L4: Projects sometimes do not work as planned
because of lack of preparation on the side of aid
providers or because they introduce technologythat has not been well-established yet.
• L5: Projects should be implemented in a waythat keeps a good balance between numericalsimulation and actual observation that uses it.

Application of Japan’s Knowledge, Experience, and Lessons to International Cooperation Projects Relating to Hydrological Services41

6. How to Apply Japan’s Lessons toward Hydrological
Service Modernization in Developing Countries

To apply lessons learned in Japan (describedin sections 2, 3, and 4) to the modernization ofhydrological services in developing countries, thefollowing recommendations should be considered:

6.1 Use a holistic approach todisaster management to promote
effective cooperation among disastermanagement facilities.
The basic principles of DRM and mitigation are these:(i) avoid establishing settlements in high-risk places,
so that no damage will result even if a hazardous
event occurs; (ii) control hazards with DRM facilities
and structures; and (iii) escape (or provide rescue)
from hazards or high-risk situations. These three arecomplementary to each other. Components of thefirst principle include land use control and waterproof
houses; the second includes dykes, water gates, anddams; and the third includes evacuation, damage
mitigation actions, and rescue. Arranging the best mix
of structural and nonstructural measures is the key
consideration for their integration.
To achieve the first principle, it is necessary to control
the use of land where flood risk is high by providing
information such as inundation risk areas and depths.
To achieve the second principle, it is necessary tooperate structures such as dams and to carry out
emergency measures such as sandbagging on dykes;
both activities are based on hydrological information.
For water-related DRM facilities and structures,proper operation and management in emergency is aprerequisite. Improper operation of dams, weirs, andwater gates may result in their poor performance or
can even increase damage. In particular, the use of42

retarding basins assumes flood damage to the areathat is supposed to be compensated for afterwards.
Facilities and structures should be operated withgreat care and coupled with adequate information
management for effective performance during
disasters. As structural measures increase safety
against floods, they also require more information toholistically understand the conditions in rivers andother areas, the status of facility operations, and flood
forecasting. This is true for two reasons: (i) during aflood, flow-controlling facilities demand more precise,careful operation; and (ii) if floodwaters exceed thecapacity of facilities or levees break, the inundation
area may rapidly expand.
To achieve the third principle, organizations
concerned are expected to issue evacuation orders
and conduct relief activities, and people are expected
to make decisions about evacuation on theirown. Such actions should be based on hydrologic
information such as the rainfall situation, river waterlevels, and inundation areas and depths.
The modernization of hydrological services
should be carried out with clear purpose, and withthe understanding that it will enhance disastermanagement by providing improved hydrologicalinformation.

6.2 Both the future vision and theimplementation plan should be realistic
and keep in mind the existing capacityof hydrological services in the country.
Where disasters are an impediment to the economic
development of a country, such as in East andSoutheast Asia, a decrease in disaster risk andModernization of Hydrological Services in Japan and Lessons for Developing Countriesimproved flood safety are likely to promote economic
development. Some developing countries experience
rapid economic growth in a short period of time. For
such countries to ensure sustainable development,
they may need different sets of hydrologicalinformation at different development stages, with
contents, accuracy, and quality improving over time.
The institutional arrangement of hydrological services
should be structured to capture and respond to suchchanging needs quickly and flexibly.

6.3 Uncertainties in flood forecastingshould be effectively communicated.
Forecast information regarding natural disasters
involves uncertainties: some may originate inuncertainties of the natural phenomena, and others
may be from the simulation technology. Whilesimulation uncertainties may decrease as technology
develops, those from natural phenomena are unlikely
to decrease even with advanced technology.
Uncertainties involved in simulation outputs basedon model calculation are a serious issue in prediction,
forecasting, and warning of phenomena around theworld. For this reason, Japan struggled with many
problems through trial and error, including the “boywho cried wolf” issue, before implementing systems
for flood forecasting and warning, debris flow disasterwarning information, earthquake early warning, andvolcanic eruption alert information. In fact, before
2004, no evacuation advisory or orders were issued
before levees breached or sediment disasters
occurred.
In 2004, the Cabinet Office developed guidelines
for the preparation of a manual on making proper
decisions about issuing evacuation orders andadvisories, with the goal of encouraging local mayors
to issue them proactively. Following the guidelines,
mayors started issuing evacuation orders that may
not have been necessary. Consequently, the publicbegan to wonder if they really had to evacuate and toquestion the reliability of the orders.
Because of these situations, efforts have been
made to develop easy-to-understand criteria to help
mayors decide when to issue evacuation orders andadvisories. In addition, based on lessons learned
from the 2015 Kanto-Tohoku heavy rainfall, in whichhydrological information did not lead to successful
evacuation of local residents, more effective methods
for providing information have been reviewed.
Despite a recognition in Japan that more accurate
information is always desirable, few recommend
withholding or not using disaster information in cases
where forecasting data do not completely coincidewith observed data. Most people agree to use suchinformation; they accept the present level of accuracy
in forecasting and understand that forecastingalways contains some level of uncertainty. Structural
measures alone cannot deal with all disasters, so to
reduce damages as much as possible, nonstructural
measures using forecasts and other types of
information are particularly important.

6.4 Development of hydrologicalservices and systems should be driven
by user needs.
Information delivered through hydrological services
should not be prepared from providers’ perspective,
in which information is reviewed and provided
for the convenience of administrators. It should
be user-oriented, reflecting the needs of different
individuals and groups for actions and decisions.
The preparation of user-oriented information can bedivided into four stages: (i) discussion of how people
should act to mitigate damage; (ii) determinationof what information they need to act properly; (iii)
discussion of how to obtain such information (e.g.,what simulation is needed) and how it should beprocessed, with the discussion focused on helping
people understand the information and on developing
an analysis system; and (iv) selection of input andoutput data after considering what data are needed
for such simulation and processing.

6.5 Hydrological services and rivermanagement should be institutionallyintegrated.
River and basin management covers various factors,
including disaster management, river water use,and conservation of the river environment. Anyof these factors involves a number of intricately

How to Apply Japan’s Lessons Toward Hydrological Service Modernization In Developing Countries

43intertwined stakeholders who may have different
needs. For example, during a flood, populations
located upstream versus downstream, or on the left
versus the right bank, may have different priorities
to ensure safety; flood management must therefore
take a balanced approach to safety that is basedon integrated river basin management and takes all
relevant perspectives into account. Over time, efforts
to manage water-related disasters in Japan have led
to the concept of integrated river basin management
and to a mechanism allowing central managementof river basins by authorities. These approaches
were institutionalized under the revised River Law of1964. Integrated management of river basins requires
collecting/analyzing real-time hydrological data of
the whole river basin, as well as archiving/studyinghydrological data for appropriate management.
Japan built its system of hydrological services (anddeveloped needed technology) in order to meetthese requirements, as well as similar requirements
for water use management and river environment
enhancement. These attempts to promote moreadvanced integrated management of river basins
have provided the foundation of social and economic
development in Japan today. Integrated managementof river basins is not only the core concept of Japan’s
technical cooperation with developing countries,
but also part of a worldwide movement—introducedin the Rhine, the Thames, and other areas where
localized management was mainly used in the past.

and police authorities, and the Self-Defense Forces inan effort to prevent disasters from occurring, assist
residents in evacuating safely, and provide emergency
response quickly.

Based on its long experience and River Law, Japan
employs a unique river management system, inwhich river management authorities have centralized
control over rivers in the country and provide
hydrological services.

6.6 Long-term support is needed toensure the sustainable operation ofmodernized systems.

River management authorities (MLIT, prefectural
governments) accurately monitor facilities for rivermanagement, develop observation networks toprecisely monitor river water levels and rainfall in thebasin, and use a large volume of observed data toaccurately forecast water levels and discharge. They
analyze these data to forecast floods and inundation.
The collected hydrological data and forecast
information are used by river management authorities
themselves and also delivered to municipalities, fire

44

Generally speaking, nonstructural measures suchas flood forecasting are less costly than structural
measures. In many cases, if part of the budget forstructural measures was instead earmarked for
nonstructural measures, that would be enough todevelop a flood forecasting system. In Japan, thehydrologic services are appropriately considered
as DRM measures, and the budget is secured.
In addition, since hydrological information isindispensable in allowing the government to conduct
its own business, the services have been securely
maintained. For these reasons, it is advisable thatorganizations responsible for river management also
perform related observation.
Hydrological services are inseparable from water
management: They do not deal just with observed
data of rainfall, river water levels, or river discharge,
but change their contents according to different
water management issues. Therefore, institutionalarrangements should seek to ensure not only
data connection, but also organic links between
institutions; ideally hydrological services and water
management should be integrated, as has beenrealized in Japan.

There have been many cases of technical cooperation
on hydrological services in which facilities andstructures are not sufficiently maintained, andexpected outcomes are short-lived. Information is
helpful only when it is used, and only then are any
problems with it noticed. Technical cooperation
should be extended beyond the stage when newly
introduced hydrological services are put in place toinclude the stage when information is successfully
delivered.

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

ANNEXES

Annexes4546

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

CountryabCategory

#11

#11

A

NASA,
NOAA,
USGS

JICA

Donor

B

7 (susceptibility
maps fordebris flow andlandslides)

1

Type of project #1

C

unknown

unknown

Project name/
ID# of report/
reference number

D

Satellite derived national map
updated several times per
day that shows soil moisture
content and identifies areas
as high or low possibility oflandslide/debris flow

Implementation of Weather
Radar System in the City ofVientiane

Project descriptionE

Answer sheets to questionnaire seeking feedback on technical cooperation projects

The map provides qualitative
information on areas withhigher soil moisture.

1. This radar system helped
to understand the area of rainsystem. Especially it is helpful
for airport operation.

Positive feedback
and reason(s)FAnnex 1: Feedback on Technical Cooperation Projects

2. The map only shows areas
with high relative humidity
but it is not based on otherdata to indicate probabilityof landslides (e.g. flat areas
are often indicated as highpossibility of landslide
because of high saturation,although the topography
makes it impossible).

1. The map is developed witha qualitative scale which is
not correlated to quantitativevalues.

2. It cannot obtain
precipitation value, since
Radar coefficient cannot be
determined.

1. It cannot be operated overcourse of 24 hours becauseof shortage of electricity.

Negative feedback
and reason(s)G

There is no
personnel that
can transformthe productfrom satellite
information
into usefulquantitative
information.

Regarding G2,
it was better
if the radarsystem andrain gauge were
implemented
at the sametime. If it is so,
precipitation
value can beobtained

Any additionalcomments

HAnnexes

47

CountrycCategory#11

A
Type of project #1

C

JICA and 7. Tsunami atlasothersDonor

B

unknown

Project name/
ID# of report/
reference number

D

Tsunami atlas

Project descriptionE

Answer sheets to questionnaire seeking feedback on technical cooperation projects

The atlas contains several
maps indicating the possible
areas affected by tsunamis ofdifferent return periods.

Positive feedback
and reason(s)F

The scale of the maps andresolution is not known at the
moment since it cannot be
digitally confirmed.

The map should beavailable to the public as adownloadable version but it
cannot be found on any of theCentral American agencies
for disaster management.

Methodology is not clear
about the calculations ofmaximum wave height andvelocity and therefore there
might be large uncertainties
in run-up and inundated area
calculations. Additionally,
it is uncertain on which
topography and bathymetrymaps were used.

Negative feedback
and reason(s)G

It is uncertain
if the atlasis reliable
since themethodology
to derive them[tsunamis]
cannot beverified, and
it is not welldescribed.

Any additionalcomments

H

48

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

CountrydeCategory

#11

#12

A

UNDP GEF

JICA

Donor

B

2, 3, and 4

Type of project #1

C

Projet SAP-Bénin(CIRDA Regional
Program)

Project forstrengthening
Flood Risk
Management in
Lai Nullah Basin

Project name/
ID# of report/
reference numberD

To strengthen climate
information and early
warning system for resilient
development in Africa. We
aim to deploy 80 automatic
telemetric stations for rain,river water level and marine
conditions measurements,
and also strengthen national
institutions capacities to use
the data and information forplanning and implementationof quick reaction (disastercases: flooding, drought,
severe wind, coastal erosion
and sea level rising) and longterm development strategy.

Establishment of early
warning system for Lai
Nullah based on installedrain gauges and discharge
gauges.

Project descriptionE

Answer sheets to questionnaire seeking feedback on technical cooperation projects

c. national (governmental)
leadership development inearly wayb. study missions to learn
from EWS existing in others
countries

a. inter-agencies and interprojects synergy upon project
launching

2. Collaboration with local
authorities and community
assures effective alerts andevacuation

1. Installed automatic rain
gauges provide basic andeffective early warning for Lai
Nullah catchment

Positive feedback
and reason(s)Fb. Less management
capacity demonstrated bygovernmental staff in chargeof project management!

a. Less motivation of national
staffs in charge of datacollection, forecasting andwarning due to less support
form government

Detailed hazard and risk
mapping of Lai Nullah
catchment was not within
scope of the project, resulting
in continuous encroachments
and development inhazardous areas

Negative feedback
and reason(s)G

The projectcontinues to besustained after
completion,
could bereplicated onother flashy/ torrential
catchments ofthe country tomeet similar
objectives

Any additionalcomments

HAnnexes

49

CountryfffCategory

#12

#12

#12

A

JICA

World
Bank

Donor

B

7

3

7

Type of project #1

C

Unknown

Unknown

WKCDD/FMP

Project name/
ID# of report/
reference number

D

4. Income-generating
activities assisted thecommunities.

Construction of evacuation
centers

2. Sanitary facilities provided
were good.

1. Provided safe area forevacuating the community

2. Flood hazard maps andevacuation maps require
updating.

1. Proper coordination
channel not discussed.
Meaning maintenance of the
facility during non-flooding
season is poorly done.

Real-time data cannot becollected.

Manual system and data is
not collected regularly.

2. Poor accounting skills ofcommunity organizations
meant a lot of funds weremisused.

2. Community participationin the projects encouraged
ownership.
3. Protection of springs to
help conserve river sources.

1. Poor quality of someworks due to lack ofproper supervision during
construction.

Negative feedback
and reason(s)G

1. Introduction of soil
conservation structures
reduced wash loadconcentrations in the river.

Positive feedback
and reason(s)FRehabilitation of RGS stations Most of the stations are now
operational.

Flood mitigation programthat involved several
activities aimed at preserving
catchment areas andreducing wash load in theriver.

Project descriptionE

Answer sheets to questionnaire seeking feedback on technical cooperation projects

Existence ofseveral flood
coordinationcommittees
makes itdifficult tomanage thecenters.

Lack of proper
planning when
deciding the
projects to be
implemented.

Any additionalcomments

H50

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

#14

#21

#13

h

b

g

#13

#21

Country

Category

A

JICA,
WB,
DANIDAC

2Type of project #1

8

JICA and 4

JICA

Donor

B

Unknown

Unknown

Project name/
ID# of report/
reference number

D

Improvement ofMeteorological Radar System,
Water level observation,
Hydrological gauging
equipment, Water-gauging
equipment, rainfall gauging
stations

Implementation of measuring
devices for water level
and rain with very simple
materials (plastic bottles, PVC
pipes, simple radio networks
and cell phones). The
instruments are calibrated tothe community’s perceptionof floods. The instruments areconnected to a volunteer’shouse where a light meter
indicates situations.

Development andimplementation of rain gauge
for monitoring and alert aboutsome thresholds previously
specifiedProject descriptionE

Answer sheets to questionnaire seeking feedback on technical cooperation projects

Help to monitor and forecast
flood, rainfall, cyclone;development of national
water resources database

3. Works with a car battery
which allows enough charge
to survive electricity outages
during storms

2. Cheap materials make iteasy to replace in case ofdamage from floods.

1. After its installation inearly 2010 there has been nolife lost in areas where thissystem exists.

2. Can be manufactured withparts which you can obtain at
the local shop.

or

1.Can be purchasedfrom some international
distributors

Positive feedback
and reason(s)FIs veryimportant toimplement
this project
nowadays; weonly have 40%of river withrain gauge. And
also can beused for radar
validation.

Any additionalcomments

H

Fragmented approach;blending of different
technologies that are difficult
to integrate in a model,
post-project operationand maintenance. Regular
updating of the system

3. Does not keep a history ofrecords.
How tointegrate thedata fromdifferentsources toimprovethe model
performance.

Regardingpoints in G, thesystem still
2. It is empirical and although needs to be
improved toit has reduced loss of life
during extreme events, it does have a formal
observation
not fulfill all the objectives
system thatof an early warning system
according to the definition of keeps history
records.
UNISDR

1. Values are not accurateenough to keep a monitoring
system.

2. The second one is not soaccurate

1. The first one can be very
expensive.

Negative feedback
and reason(s)GAnnexes

51

CountrybcCategory

#14

#14

A

InterAmerican
Development
Bank

JICA,
KOIKA,
Taiwan

Donor

B

6

7. Infrastructure

Type of project #1

C

Unknown

Unknown

Project name/
ID# of report/
reference number

D

The Central American
Probabilistic Risk Assessment(CAPRA) is software basedon GIS to calculate risk for
different hazards.

Puente de la Amistad(Friendship Bridge)

Project descriptionE

Answer sheets to questionnaire seeking feedback on technical cooperation projects

By introducing data about
population, socioeconomic
information and hazard it
calculates risk.

The software is supposed tobe freely available online, andbe user friendly.

Reconstruction of damaged
bridge in the main access to
Panajachel community

Positive feedback
and reason(s)F

The biggest
issue with thisproject was
the lack of
coordination
betweensupporting
agencies.

Any additionalcomments

H

1. The software has only been To date several
used with outdated proxies
projects havebeen done
2. The software is neither
using this tool
available nor user friendly.
although theCommonly it is very difficult
results can only
to understand.
be considered
3. When the technology has
as preliminary
been transferred, via CDs the since it has
software is not possible tobeen done
install.
with outdated
4. Workshops to teach about proxies
and hazard
the software have usually
failed since most of the time information
is occupied for unsuccessful only as
exercises.
installations

3. The bridge is evidently
poorly designed, as it is muchnarrower than the bankfull
width.

2. After its inauguration,
during the first storm of
the 2010 season the bridge
collapsed once again.

1. The project changed
funding agencies several
times before settling with
the Korean International
Cooperation Agency (KOIKA).

Negative feedback
and reason(s)G52

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

g

g

#16

i

Country

#16

#23

#22

#15

Category

A

JICA

JICA

JICA

Donor

B

7

4

4&6

Type of project #1

C

Unknown

Unknown

Strategic
Strengtheningof flood warningand management
capacity ofPakistan

Project name/
ID# of report/
reference number

D

Obtaining satellite images
for measures of changes inmorphology after a disasterby flood or debris flow

Implementation of early
warning system surface
elevation

Development of flood warning
framework, hazard mapping,model calibrations for Indus.
Capacity building for flood
management stakeholders inPakistan.

Project descriptionE

Answer sheets to questionnaire seeking feedback on technical cooperation projects

3. Sustainability of project
objectives could not beensured3. Hazard mapping of Indus
river using 1D/2D modelingtools

Very useful information forunderstanding behavior andchanges in terrain.

The most vulnerable
communities are also themost dangerous because of
criminality, which can stop a
project like this.

2. Direct involvement ofprovincial and district level
stakeholders could not beensured2. Capacity-building
exercises at working group,
mid-tier flood management
stakeholders

Can be manufactured usingparts which you can obtain at
the local shop, and is usefulfor low-income communities.

1. Not enough detailedhydrological data sets wereavailable for ideal calibrationof modelsNegative feedback
and reason(s)G

1. Introduction of new floodmodeling tools in Pakistan
in collaboration with help ofinternational experts

Positive feedback
and reason(s)F

Could be evenmore useful
if the images
can be updated
after a disasterevent happens.

Data availability
limitations need
to be identified
in developing
countries.
Leapfrogging
technologies
may be used
to overcome
lack ofinfrastructure
and resources.
Sustainabilityof project
objectives
needs to beensured.

Any additionalcomments

HAnnexes

53

b

#16

JICA

World
Bank

Donor

B

6

1, 2, 4, 6

Type of project #1

C

Unknown

PPCR/BRCH

Project name/
ID# of report/
reference number

DE

2. Includes sections forchildren, with games, small
drills and informative quizzes
about debris flow

1. Contains simplified
information about theprocesses that produce a
debris flow

Project is currently inprogress. Project aims todecrease the loss of life andproperty due to flood through‘end to end early warning
system’ and enhance thecapacity of flood and weather
forecasting.

Positive feedback
and reason(s)FAfter implementation it isuncertain about the follow-up
from local authorities since
they changed some time after
its opening.

Negative feedback
and reason(s)G

Regardingpoint G it isimportant thatall stakeholders
follow up on
projects.

Project helps
to upgrade thecapacity of
Department ofHydrology andMeteorology

Any additionalcomments

H

G: Negative feedback					Please write your comments in terms of negative aspects of this project and the reasons*negative aspects could include insufficient outcomes
H: Any additional comments					This includes comments such as “if the project/component/implementation had been designed asfollows, it would have improved xxx or it would have been better for the following purpose.”

Implementation of an
informative museum about
debris flow in a commonly
affected area. The museum
is based on the Kobe
Earthquake Memorial
Museum for disaster

Weather radar/Floodforecasting/Automaticweather station/Capacity
building

Project description

A: name of country				
B: name of donor				
C: type of project						1. Implementation of weather radar				
2. Implementation of rain gauge					3. Implementation of gauge for measuring water surface elevation			4. Implementation of early warning system for flood				5. Implementation of early warning system for debris flow			
6. Capacity building						7. Other						D: Project name/Description/ID or reference					Please specify the name of project as well as ID # for future reference. If you don’t know how toreference the project but you know the story, please write as unknown
E: Project Description					Please explain in as much detail as possible 			
F: Positive feedback					Please write your comments in terms of positive aspects of this project and explain the reasonsjCountry#16

CategoryA

Answer sheets to questionnaire seeking feedback on technical cooperation projects

Annex 2: Technological Development Examples

Examples of hydrological services
related technological development:• Radio wave current meter• Image processing type flowmetry• Provision of river information by cellular phone• X-band multi-parameter rain radar for torrential
rainRadio wave current meter
Using noncontact type radio wave current meter,
flow measurement can be conducted safely andcontinuously even at the time of a large-scale floodwith the help of recent development of technology.

54

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

Annexes

55

Surfaceby電
波 流flow
速 rate計 measured
に よる表
m/s）
面 流 速 （the radio wave current meter (m/ s)

1.5

2.5

3.5

4.5

0:00

6:00

1st day

12:00

18:00

0:00

6:00
2nd day

12:00

18:00

time, hour

0:00

6:00

3rd day

12:00

Portable-type radio wave current meter

18:00

0:00

6:00

4th day

12:00

18:00

114.5
0:00

115.5

116.5

117.5

118.5

120.5
S表
urfacerate
面 flow
流 速（電 波 流 速 計 ）(Radio wave current meter)
119.5
Water
水 位level

2

Reference：
流 量 観 測 の 高 度 化 マ ニ ュ ア ル （高 水 流 量 観 測 編 ）土 木 研 究ICHARM編所
http:/ / www.icharm.pwri.go.jp/ ryukan/

Observation example of the radio current meter・It is measurable continuously for a long time.
・The left figure is an example of measuring thesurface flow rate continuously by the radio wave
current meter. (Average 10minutes)

Fixed-type radio wave current meter (Set plural in the transverse direction)

By emitting radio wave toward the water surface from the sensor installed on the structures such as bridges,
It can measure the surface flow rate applying Doppler shift at the time of sending/ receiving of the wave.

Ø Using noncontact type radio wave current meter, flow measurement can be conducted safely and continuously even at the time of alarge-scale flood with a help of recent development of technology.
Ø In the Public Works Research Institute/ ICHARM, a study on advancement of the flow rate observation using this technique is proceedingnow.

R adio wave current meter

Water
level
水 位
m）
（(m)

56

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

LSPIV image

Measurement example in Maebashi (Tone River)

References：
M. Muste, I. Fujita and A. Hauet, Large-scale particle image velocimetry for measurements inriverine environments, WATER RESOURCES RESEARCH, VOL. 44, W00D19,
doi:10.1029/ 2008WR006950, 2008
Ichiro Fujita, Masaki Kitada et al：Spatial measurements of snow melt flood by image analysis
with multiple-angle images and radio-controlled ADCP，The Journal of Japan Society of Civil
Engineers, Ser. B1（hydraulic Engineering）Vol.70, No.4, pp.613-618, 2014.
Ichiro Fujita, Hiroki Hara and Atsuhiro Yorozuya, EVALUATION OF IMAGINGTECHNIQUE ACCURACY FOR DISCHARGE MEASUREMENT AND DEVELOPMENT OF REAL TIMESYSTEM FOR SURFACE FLOW MEASUREMENT, Journal of Hydroscience and HydraulicEng. No.30-1, pp.15-28. 2012

STIV image

ADCP（移動 平 average)
均 ）ADCP(Movement
ADCP（移動 平± average±均
標 準 偏Standard差 ） deviation)
ADCP(Movement
SS
TIV
TIV
LS
PIV
LS
PIV
Riverbed河
床 高height

検 査 ラインの 設 定

3The flow rate measuring methods by using video images photographed with the fixed camera are as follows:l Determining the light and shade patterns in a certain range drifting the water surface of the screen as particles, it is to analyze the movement amount and tocompute the flow rate (LSPIV method).
l Establishing the inspection lines so as to be along the mainstream direction, calculate the average flow rate from the inclination of the stripe pattern whichappears on the time-space image when the brightness values on the inspection lines are put thereon in the temporal axes direction. (STIV method)Ø A technique to measure surface flow rate of the river, by using video images photographed with the fixed camera, has been developed.
Ø The night observation with the far-infrared camera and the continuous observation by using CCTV camera for river management are also
carried out.

Image processing type flowmetry

Annexes

57

Via the internet
Contents:• Rainfall• Radar rainfall• Water level, etc.

via the cellular phone

Provision of river information by cellular phone458

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

High frequency (5-fold)High resolution (16-fold)X-band MP radar- Min observation area: 250 m mesh
- Observation interval: 1 minute- Time to end user: 1 to 2 minutes- Obs. Radius: 60 km* In contrast to C-band radar (observation radius of 120 km), which is suited for broad-area
precipitation observations, with X-band radar (observation radius of 60 km), detailed and real-timeobservation of local heavy rain is possible though the observable area is small.

世 田 谷

大 手 町

雑 司 ヶ谷Existing radar (C-band radar)- Min. observation area: 1 km mesh
- Observation interval: 5 minutes- Time to end user: 5 to 10 minutes- Obs. Radius: 120 km

X-band multi-parameter rain radar for torrential rain

１．概要
[日本の水文サービスの概要]
河川及び流域のマネジメントには、災害対応、河川水の利用、河川環境の保全等の多様な要素が含まれているが、これらのどの要素をとりあげても、一つの流域の中に利害関係が複雑に絡み合う多くの関係者が存在している。例えば、河川の上下流や左右岸に位置する地域間で洪水時の安全性を巡る利害関係の問題があり、流域の統合管理のアプ
ローチからバランスをとった安全レベルを持つ洪水マネジメントが不可欠である。日本が水災害対策について長年苦労してきた結果として、流域の統合管理の考えや河川管理者が流域の水を一元的に管理する仕組みが生まれ1964年の新河川法などで制度化された。
流域の統合管理を行うためには、流域全体のリアルタイムの水文データの集約と解析が必要となるほか、より的確な統合管理を行っていくための水文データの蓄積と分析も必要であり、様々な技術開発も行いながら、それに呼応した水文サービスの体制が整えられてきた。水利用や環境面も同様であり、それらも含め、その後もより高度な流域統合管理への進展が図られ、今日の日本の社会･経済の発展の礎となってきた。こうした日本の流域統合管理は、途上国への技術協力における核となっているだけでなく、以前は地域的管理が主体であったライン川やテムズ川などでも取りいれられるなど、世界的な潮流となっている。
日本では、これまでの長い経験を踏まえて、河川法には河川管理者が一元的に河川を管理し、あわせて水文サービスを実施するという、他の国にあまり類例をみない体制が明記されている。
国土交通省や都道府県などの河川管理者は、堤防やダムなど河川管理施設の状況を正確に把握するとともに、河川の水位や流域内の雨を精緻に把握する観測網を整備し、観測した膨大なデータを解析して水位・流量の的確な予測を行っている。そして、集約した
水文データや予測情報を、自ら行う水マネジメントの様々な場面に用いるとともに、都道府
県や市町村などの自治体、消防、警察、自衛隊など数多くの組織に提供されて、災害発生の防止、住民避難の支援、応急対策などに活用されている。
[日本の水文サービスの発展過程と知識・経験・教訓の係わり]
日本の水災害対策は、社会・経済の変化、大災害、技術革新などを契機として、近代化が進んできた。その動きは「個別あるいは地域を守る防災から、流域の統合管理に」、「氾濫を想定しない許容しない施設整備から、氾濫を含めた防災に」、「過去の災害に基づく計画洪水を対象とするものから、計画を上回る規模の災害への対応に」といった変化である。これまで、日本では、河川の管理と水文サービスが一元化されていることで、こうした流れの変化にも的確に対応することができた。
日本は、洪水災害以外にも自然災害が発生しやすい国であり、様々な種類の災害に対する考え方が相互に影響を及ぼしている。「設計に用いた外力よりも大きな外力（Ｌ２）に見舞われた場合でも致命的な事態に陥らないようにする考え方の採用」、「観測データの同化に基づく、より精度の高い予測の実施」「情報を受けとった者がとるべき行動に準拠したレベル化」といった考え方は洪水災害対策にも共通する。

Annexes59水文データの観測を行う機器も、ユーザーの正確性向上のニーズに応えて技術が開発されてきた。一方、水文サービスとは異なる分野で発達した技術が、水文観測に導入されたものとしては、雨量をリアルタイムで面的に観測する技術として水文観測に取り入れられているレーダ雨量計や、ＩＴ技術の進展によって、大容量のデータを用いた詳細な解析、使い勝手のよい画面表示、携帯端末を通じた情報提供などが可能となったことがあげられる。
日本の防災対策の進展の過程で、いくつかの問題を解決してきている。例えば、「防災施設への過剰な期待による災害時の対応能力の低下」、「避難勧告・避難指示の混乱」、「不確実性を伴う情報に基づく行動に対する責任」などがある。これらのうちいくつかでは水文サービスの近代化が問題の解決に寄与している。
[日本の水文サービスに係わる組織等と水文サービス近代化]
日本政府の組織が大きく見直されたのが、2001年の中央省庁の再編である。建設省と気象庁が国土交通省の一部となり、また、新たに政府の重要事項を担う内閣府が設置されて、防災行政の政策立案や関係省庁の調整を行うなど、防災行政を実施する体制の抜
本的な改善が図られた。
災害の被害を最小限度にとどめるには、行政による事前防災や危機管理といった「公助」、住民が自分自身を守る「自助」、地域社会で守る「共助」が、それぞれ十全に機能することが重要である。地域の住民は「共助」の一つの形態として、自分たちを守るための水防活動を実施している。
災害時の住民への情報伝達においては、テレビなどのマスメディアが大きな役割を担っており、法律上も災害時の情報提供に大きな役割を果たすことが期待されている。災害時には行政とマスメディアが一定の連携をして住民への伝達を図っている。
日常の水文情報に対するニーズは決して大きなものではなく、民間企業で水文サービスの実施に意欲を持つ者はなかったため、官民が連携して必要な資金を賄うことによって、財団法人河川情報センター（FRICS）が設立された。
現在、水文情報は、河川管理者によるダムや水門などの施設の操作・管理、災害発生時における異常の監視、氾濫の予測などに用いられるだけでなく、市町村が行う避難勧告
や避難指示などの避難情報の発表や避難場所の設置運営などの判断基準、防災・減災活動に携わる消防・警察・自衛隊などの活動、大規模災害に設置されるに対応する政府
災害対策本部、電力やガスなどのライフライン及び高速道路や鉄道などの交通インフラの適正な管理、マスメディアによる住民への周知など、様々な目的で共有されている。
［これまでの水文サービスに関する国際協力プロジェクトにおける日本の知識等の適用］
日本における水文サービスの近代化は、河川を実際に管理する者が水文観測・解析・加工・提供を行っていることで効果的に推進されてきた部分が大きい。韓国(建設部)、中国（
水利部）においても同様のことが効果的近代化に繋がったと思われる。多くの場合、構造物対策に必要とされる費用の一部を洪水予測システムの構築に充てることでも、必要な規模の予算を確保できることが多い。こうして、洪水予測システムが防災対策として適正に位置づけられ、財源が確保できたものと考えられる。
60

Modernization of Hydrological Services in Japan and Lessons for Developing Countries

一方、多くの開発途上国では、河川を管理しない組織が水文観測と解析を行っている。
このような場合、関係機関の間で連携がなされたとしても、実際に観測データを使う組織の変化するニーズが観測に柔軟に反映されない。フィリピンでは、河川管理は公共事業
道路省が所掌しているのに対し、JICA支援の洪水予測プロジェクトはフィリピン気象庁（PAGASA）が受け入れ機関となった。このため、フィリピン国においては、洪水予測についての適正な予算配分がされず、過去において洪水予測システムの維持管理がうまく行われなかった可能性がある。
［途上国の水文サービス近代化のための日本の教訓の活かし方］① 防災施設と有機的かつ効果的に共同できるよう、災害のマネジメント全体で考える
水文サービスの近代化は、明確な目的をもって実施されるべきである。この意味で、水文情報の改善により災害マネジメントを進めるという視点が重要である。
② 既存の能力を念頭に、将来像と現実的な実施計画を考える
国の経済が急激に拡大するような国においては、開発段階に応じ、異なる内容、精度、品質を持った水文情報が必要になることがある。水文サービスの体制はこのような変化するニーズを迅速・柔軟に捉え、対応できるものにする必要がある。
③ 洪水予測における不確定要素の有効な伝達
自然災害に関する予測情報には不確定性が含まれている。構造物対策だけで全ての災害に対処することはできないため、出来るだけ被害を軽減するためには、予測や他のタイプの情報を使った非構造物対策が特に重要である。
④ 利用者のニーズによる水文サービスとシステムの展開
水文サービスで提供する情報は利用者優先のものとし、様々な個人・団体の行動や判断の必要性を反映すべきである。
⑤ 水文サービスと河川管理の制度的な統合
水文サービスは水マネジメントと不可分のものである。それは、単に降雨・水位・流量の観測データを取り扱うだけではなく、様々な水マネジメントの問題にあわせてその内容を変化させるものである。従って、単なるデータ連携ではなく、有機的なつながり（理想的には
水文サービスとの統合）を持つ体制としていくべきである。
⑥ 近代化したシステムの持続的運用を保証するための長期的支援
情報は使われて初めて役に立ち、実際に使われるまでは問題が表面化しないことが多い。技術協力は新たに水文サービスが導入される段階に加え、情報がうまく提供される段階を含むべきである。

Annexes61

Contact:
World Bank Disaster Risk Management Hub, Tokyo
Phone: +81-3-3597-1320
Email: drmhubtokyo@worldbank.org
Website: http://www.worldbank.org/drmhubtokyo
The World Bank Disaster Risk Management Hub, Tokyo supports developing countries tomainstream DRM in national development planning and investment programs. As part of the
Global Facility for Disaster Reduction and Recovery and in coordination with the World Bank Tokyo
Office, the DRM Hub provides technical assistance grants and connects Japanese and global DRM
expertise and solutions with World Bank teams and government officials. Over 37 countries havebenefited from the Hub’s technical assistance, knowledge, and capacity building activities. The DRM
Hub was established in 2014 through the Japan-World Bank Program for Mainstreaming DRM in
Developing Countries – a partnership between Japan’s Ministry of Finance and the World Bank.