The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Urban River Managementin Japan
Masafumi ITO દ⮮ ዁ᢥJapan River Restoration NetworkJapan River Research Center
Nature Oriented River Management Support Center
Outline of the Presentation

1.Characteristic of National Land and Rivers

2.Previous River Management and its SideEffects

3.Latest Trend/Concept of River Management

Asian River Restoration Network (ARRN)

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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Characteristic of National Land and Rivers

Location of Major Cities in Japan
NagoyaOsaka

Hiroshima

SapporoKitakyushu

SendaiTokyoYokohama

70% of Japanese national land is covered by mountainous area.
As so major cities with large population mostly formed along rivers inlow elevation land.
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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Urban Area Formed in Lower Elevation

Floods Death Toll

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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Amount of damage caused by floods
Amount of damage caused by floods (1011 yen)
Flooded area (10,000 ha)

Amount of damage per unit area
(10,000yen/ha)

Amount of damage
per unit area
Floodedarea

Amount of damage
caused by floods

Previous River Management and its Side
EffectAsian River Restoration Network (ARRN)

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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Flood Control Measures from the Perspective of Watershed

Flood Control menu in the river
Flood mitigation in the basin
Measures by land use

Flood Control Efforts on the Improvement of the Degree of Safety

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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Flood Control Efforts on the Improvement of the Degree of Safety
Installation of rainwater infiltration facilities
Capture rainwater on the school grounds.
Used as a multi-purpose facility

set up a facility to houseand housing complexes.
Improved paved
surface of the roadFlood Control Efforts on the Improvement of the Degree of Safety

the Metropolitan Area Outer
Underground Discharge Channel

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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Flood Control Efforts on the Improvement of the Degree of Safety

Transition of River Law

1896

1964

1997

Birth of modern law forriver improvement

Systematic maintenancesystem for 2 contents

The overall maintenanceof 3 contents• Introduction of basin
consistent management
system• Adjust the relation of 2 factors• Maintenance andpreservation of riverenvironment• Reflection of regional opinion• Introduction of planningsystemFloodControl

FloodControl

Water
Utilization

Purpose of River Policy.
• Improvement of flood control safety.
• Ensuring water essential to human life.
• Conservation and restoration of thenatural environment of the river.
• River management that balances theabove three.
Asian River Restoration Network (ARRN)

FloodControl

WaterUtilization

RiverEnvironment

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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Factors in Natural Rivers

Attempt of Making a Natural River

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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Attempt of Making a Natural River

Attempt of Making a Natural River

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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Latest Trend/Concept of River Management

Purpose for Nature-Oriented River Management“Nature-Oriented River Management” is a basic policy of river improvement
which utilizing the natural dynamics of the river.

Three considerations of “Nature-oriented River Management” is …
to create or to conserve an
original environment of riverfor habitats.

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to form the harmony with
cultural life and history ofthe region.

to create or to conserve avariety of river views.

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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Initial cases aimed to improve river environment

It Used to be the river with poor habitat,
which river banks are covered in steel sheet
pile

The results of extending river width, devised arevetment on shore, shallows and pools areformed.
And the stagnation of the border plant has
become a habitat for fish.

Initial cases aim to improve river environment
The riverbed excavation traces an original riverbed -before
after
original riverbed slide-down
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revetment works
foot protection
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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Basic Direction of River Improvement
Planar• The river improvement planning is more likely to plan spatially as toensure natural and linear width or meandering channel.
Cross-section• The channel cross-section is more likely to widen as to ensure natural andlinear width to accept flood dynamism.
River bed
• The bed is more likely to be covered by natural materials, as channel
allows river dynamics to form thalweg, shallows, pools.
Landscape• More likely to preserve or restore beautiful natural scenery with no artifacts

Indicators to Evaluate Urban River Improvement
PlanarContinuous spatialplanning• Natural and linear
width is ensuredcontinuously.

Local spatialplanning• Natural and linear
width ensured
locally

River channel thathave been crosssectional, line ruler.
• Effort can be seenon cross-section orin bedCross-section

River bed

LandscapeWidening crosssection

Channel allows
river dynamics

Beautiful naturalscenery• Spatial design• Widening one side ofbank• Widening banks on
both sides• thalweg, shallows,
pool are been
formedTemperedlandscapeThere is a naturalartificial structures

Widening bed width• Gentle slope
riverbank of soil
• Reproducibility ofthalweg• With no artifacts• Flat gravel bed

Ingenuity on
revetment edge andbanks• Vegetation on theedge of revetment• Vegetation on banks• Consideration oflandscape can beseen but thecentral artificialstructures• Historical andcultural landscape• CityscapeAcceptable boundary• No ingenuity.

• Stylized cross section
with no ingenuity

Natural dynamics
are not acceptable• Fixed-bed

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Artificial landscape• Artifacts stand out,
with noconsideration ofthe landscape
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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)
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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

PDCA cycle scheme: Maintenance of the recycling system

Efforts for Sustainable River Environment

Asian River Restoration Network (ARRN)

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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Various Programs to Support River Improvement
Support programs of river development plan for consideration
Nature Oriented River Management Adviser Program• River development support program for river administrators managed by theMinistry of Land, Infrastructure and Transport.
• Upon restoration of rivers affected by the disaster, sent experts of riverdevelopment, advise the planning of river development suit for the local condition.

Nature Oriented River Management Support Center• River development inquiry counter managed by the Japan River Research centre.
• Activities that target all stakeholders such as citizens, the private sector andgovernment agencies.
• Contents is in wide rage, such as sent lecture, hold study sessions, give advice toriver development plan, etc...

River administrator Lecture Program for citizen• Lecturers program targeting mainly NGOs, which according to the riverenvironment.
• Program is managed by the Ministry of Land, Infrastructure and Transport.

Various Programs to Support River Improvement
Programs on the sharing of river informationJapan River Restoration Network• A non political network for exchanging knowledge and technical information on
the restoration of rivers and watersheds in Japan and Asia.
• It aims to enrich the participants' knowledge and scientific technology throughmutual and multilateral cooperation, and JRRN also contributes to creation of richriver environment in Japan.

Nice-River / Nice-River Development Workshop & Symposium• Debriefing of the river conservation activities of the people, by the people, for thepeople, with cooperation of academics and river administrator.
• Symposium for people to learn the latest technology protection activities fromgovernment officials rivers or from academics.

Knowledge of stream ecology – database• Website managed by National Institute for Land and Infrastructure Management.
• Provide aggregated information centrally in the Journal of Research on theecology and related academic research was carried out in rivers of the individual
rivers so far, and the results of the study in the other rivers.
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The 9th International Forum on Waterfront and Watershed Restoration(2012/11/24)

Thank you

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