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Modernization of Irrigation Systems in Japan

Dr. Masayoshi SATOH, ProfessorGraduate School of Life and Environmental

Sciences, University of Tsukuba

INTRODUCTION

•If “Irrigation service” is defined as a direct i i d li i f hcommitment in delivering water to farmers, the

Japanese government does almost nothing , except in 7 projects of Japan Water Agency (JWA) , which was established after WW2.•In other irrigation systems, major part of whichIn other irrigation systems, major part of which originated in 17th to 19th Century, farmers serve water to themselves through the activities of water users’ organizations.

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Background of JapaneseBackground of Japanese irrigation

Major target of irrigation is paddy.Fukuoka Zeki Irrigation System,

developed in 1625 still functioning at presentat present.

Paddy is the most productive way of food production in the low lying watery plains of Japan.

Upland is used for non-paddy without irrigation.

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Japanese farmers can grow rice only once a year because of low temperature in winter.

Monthly temperature and rainfall in Tokyo, Japan

River flow in Japan fluctuates much because of erratic rainfall. Thus irrigation is a must for paddy.

25

50

75

100

125

150

175

200

Discharge (m3/s）

1972

1973No rain for more than one month in 1973

Funadabashi G auging Station, Kitakam i River

( C atchem nt area: 868.1 km 2)

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JAN FEB M AR APR M AY JUNE JULY AUG SEP O C T NO V DEC

This fluctuation gives farmers abundant water in usual times, and serious water shortage during drought.

Daily discharge in the Kitakami River at Fudabashi St. with a catchment area of 868 km2.

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Irrigation management bodies in Japan

• Most of Japanese irrigation systems are totally managed• Most of Japanese irrigation systems are totally managed by farmers through Land Improvement Districts (LIDs). After construction, all irrigation facilities are to be turned over to farmers.

• JWA managing irrigation systems, which emerged only after WW2, all the on-farm systems are managed byafter WW2, all the on farm systems are managed by LID and farmers, while main facilities are managed by JWA.

Water Management in Traditional Irrigation Systems

1 LID l1. LID operate only main parts of the facilities.

2. Remaining parts are operated by the local

iti

DiversionDam

SourceRiver

200mI III

communities.

Farmdrain

Fieldditch

I30-100m

II II

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Special features of irrigationSpecial features of irrigation system in Japan

Special features

• Water right system is established based on• Water right system is established based on the River Law (1896).

• All the projects related to land and water for agriculture such as irrigation and land consolidation are defined as land improvement project and implemented based on the Land Improvement Law (1949); Water management is also defined as a part of LIP.

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Special features (Cont.)

• LIDs normally divert water from a source river• LIDs normally divert water from a source river as they need, but in case of drought they are requested to adjust water allocation by themselves.

• Water is free at the source river, However, all the on-farm water management cost is covered by farmers with their membership fee collected by LID on a area basis.

Special features (Cont.)

• Water is free at the source river. However, all the on-farm water management cost is covered by farmers with their membership fee charged by LID on an area basis.

• In case of drought, unacceptable level of uneven water distribution emerges then LIDuneven water distribution emerges, then LID will change irrigation method from simultaneous -continuous irrigation to rotational one to get the equity.

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Water distribution by LID during drought time (Rotation)

Off-turnOn-turn

平等な水配分を実現するために 順番に時間給水する

A chain is needed.

Local farmers waiting for water coming (Isawa Heiya LID)

に、順番に時間給水する。平等な水配分を実現するために、順番に時間給水する（上）。右は、水の到着を待つムラの農民。（岩手県胆沢平野土地改良区）

Toyogawa Irrigation Project- a case of JWA management-

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Main Canal

Facilities operated by JWA and LID

Ohno Diversion WeirUre Dam

Intake gate for lateral canal

A farm pond

Operation (broad sense) consists of four functional elements.

Decision

Operation (narrow sense)Feedback

Monitoring

Feedback

Operation (broad sense) is Operation in OM&M

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Main canal: Managed by JWA?

• Main canal of Toyogawa Irrigation Project is managed (operated) by JWA officersmanaged (operated) by JWA officers including delivery of water to each lateral canal.

• However, the target discharge for each has been decided in advance in the meeting with LID JWA just Operates according to DecisionLID. JWA just Operates according to Decision.

• Decision is jointly done by LID and JWA.

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Primitive diversion weirs modernized in 1967 (Three irrigation intakes were merged.)

Kottsu Irrigation System established in 1650 for paddy area ofKottsu Irrigation System, established in 1650 for paddy area of 6,000 ha in Aichi Prefecture

Concrete weir saves labor.(Inuyama Diversion Dam)

Farmers needed heavy labor to keep water course way after flood

A Diversion Dam Managed by LID

• The diversion dam constructed in aconstructed in a governmental project was turned over to the Meiji Yosui LID, serving 5,700 ha of paddy field and 13,300 farmers.

Width of the weir: 167m

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Main canal of Meiji Irrigation system, old and modernized

Modernized: Made of concrete and guarded by fence to prevent children

from jumping into the canal

Old: Children swimming in the canal

The main canal was buried for pressured pipeline irrigation system. A promenade

was created replacing the traditional irrigation canalg

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Field TurnoutBuried pipeline system has been introduced recently, Traditional open type field

ditch reducing water management labor and conflicts.

ditch .

Government contribution to the modernization of irrigation systems

tied with changeThe Japanese gov. can not directly improve

irrigation management, but through LID.Type 1: Unification of irrigation systems in a

river basin → Conflict resolution among t i tiwater users organizations

Type 2: Canal improvement → Improving water distribution system

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Meiji Modernization project (pipeline) took away local powers for fairness.

T di i l l lTraditional local powers opposed the new water management system, insisting the continuation of gate operation by themselves.

• Main divisions of main canals and major turn-outs for lateral canal are controlled and monitored here.

• The LID hires engineers and technicians to operate this kind of modernized facilities.

Procedure of Irrigation Improvement Project Formation (Application system)

Consultation

Physical planBudget planManagement plan

Basic plan

LID Prefecutural engineers

Approval by more than 2/3of member farmers

(90% in practice)

Member farmers

LIDApplication system: Go ernment is not

Government

Implementation

Application

Survey, Approval

Government is not allowed to start any project without application to which most of the farmers have agreed.

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How Land Improvement Law works

Land Improvement Law

(Agreement by majority)

Forced participation in the project

Serious consideration on benefits from participation (especially by downstream farmers)

Forced partial payment for project (10% of total cost)

(Agreement by majority)

Request for plan, design and management

Engineers’ elaboration to benefit all the beneficiaries

When agreed, Right and Duty, and Ownership are established.

Maintenance activity of farmers for the Manno-ike irrigation tank

Thank you