Evolving approach to river management in Japan · mitigate damages in the event of flooding. River...
Transcript of Evolving approach to river management in Japan · mitigate damages in the event of flooding. River...
Ministry of Land, Infrastructure, Transport and Tourism
Evolving approach
to river management in Japan
18 April 2016
Takafumi NAKUISenior Deputy Director, River Planning Division, Water and Disaster Management Bureau, MLIT
@ Kanto Regional Agricultural Administration Office
Characteristics of Rivers in Japan
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Mountain area
Plain area
properties
population
Area
Flood –Prone Area(lower than river water level at the time of flood)
(%)
Other areas
Concentration of population and assets
in flood-prone area
Most of land in Japan are covered by mountains, and people and assets are focused in the
narrow plain area.
Characteristics of Rivers in Japan
Many rivers in Japan are very steep with a short distance from the source to sea, resulting in
rapid flow.
Length(km)
Tonega
wa
River River
Seine
Mekong
River
Joganji
RiverShinano River
Altitude(m)
Rhine
River
Colorado
River
Lorre
River
Rivers in Japan
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History of River Management in Japan
Before 19 century
○Each community implement river
management and flood control in each
region.
○Each measure of flood control and water
use were conducted without coordinating
among communities.
After 20 century
○Integrated river management is
implemented to achieve well-balanced flood
control and water use throughout the basin.
○Responsibilities and roles of river managers
and other stakeholders are clearly defined.
●Urbanization and population
increase in Catchment area
●Increase of water demand
due to the economic growth
●Increase of dam construction
for developing electric power
Coordinating regional interests
is needed for the efficient river
management and flood control .
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河川法River Law
・River manager(administrator) is designated in this Law.
・Class-A rivers are managed by MLIT, Class-B by Prefectural
Government.
・Water resource management including Flood Management is
conducted by River Managers (River Administrators).
・Human activities to protect lives and properties from flooding
and minimize damage when a flood disaster is occurring or
about to occur. (flood warning, flood-fighting, etc.)
・Municipalities bear responsibility of flood risk management
activity and direct the ‘Flood Fighting Corps’.
・’Flood Fighting Corps’ are formed by local residents living
near rivers and are active in when floods occur.
Flood Management Policy in Japan
Flood management policy in Japan is stipulated in ‘River Law’ and
‘Flood Risk Management Act’, both of which complement each other
to strengthen flood management.
水防法Flood Risk
Management Act
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Outlines of River Law
Responsibilities of River Managers
Monitoring, Planning of water resource management, and Implementing※* ex; construction of flood control facilities, operation and maintenance of facilities, permission and maintenance of water
rights, implementation of projects on water resources development, etc.
When disaster occurs, River Managers are the first responders for early recovery and
reconstruction of river infrastructures.
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Normal Discharges, Facilities for
preventing floods, Water rights
and Environment to keep the
river safe.
River Managers construct, improve, operate and maintain river atnormal times.
River Management at Normal Times in River Law
Monitoring and MaintenanceConstructing and OperatingSetting targets
Construction river management facilieties based on each river improvement plan
Operation of these facilieties to keep rivers normally
Early detection of abnormality
Routine monitoring
Maintenance
River improvement plan is
formulated through the opinion
of relatives in each river(residents, experts, municipalities etc)
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Media OrganizationsResidents
Prefectures Municipalities
Evacuation advisory,
Evacuation directive
Flood forecast
Flood forecastFlood
Fighting
Organizations
Order for action
River Office
Countermeasures to mitigate damages
River patrol
Information collection
【Response in fields】
Controlling facilities
Assisting municipalities
Emergency recovery
Assisting flood fighting activities
River administrators provide flood information for the smooth flood fighting activities,
patrol rivers, control facilities and utilize sump pumps in order to prevent and
mitigate damages in the event of flooding.
River Management during Floods in River Law
MLIT (River Offices, Regional
Meteorological Observatory of
Japan Meteorological Agency)
【coordination
when flooding】
Warnings to prepare flood fighting
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Outlines of Flood Risk Management Act
Dissemination of river information
【MLIT or prefectural governments】・Flood forecasts must be released.
(with Japan Meteorological Agency)
・Information of flood water levels must be announced
and disseminated so as to prompt residents
evacuation.
・A flood fighting warning must be issued to warn that it
is required to initiate flood fighting activities.
On-site flood fighting activities
【Administrators of Flood Fighting Corps】・Flood fighting engineering methods must be applied.
(e.g., sand bag piling up methods)
・Emergency response measures must be taken after
levee breaches (so as to prevent the spread of flood
damage)
In case of a flood disaster event
Sand bag piling up methods to respond to over topping
Hooping Method to deal with levee leakage 8
Outlines of the revised Flood Risk Management Act
Provision of flood information
【MLIT or prefectural governments】Expected inundation assumption zones must be
designated, announced and informed to related
municipalities, for ensuring smooth and prompt evacuation
from floods, and for reducing disaster damage.
In ordinary times
Support to emergency evacuation
【Municipalities】
・Methods to disseminate flood forecasts and the locations
of evacuation sites must be specified in regional disaster
prevention plans.
・Methods to disseminate flood forecasts to the users of
underground facilities must be specified in regional
disaster prevention plans.
・Flood Hazard Map must be developed and disseminated. 9