Integrated Basin Management　 in Lake Biwa and Yodo River 

Basin

Bridging Upstream and Downstream

Flood Control, Efficient Water Use and Ecosystem Protection

All Stakeholders

The 5th World Water Forum Session 3.2.1 090320

Masaki Hirowaki

Shiga Prefectural Government Dept of Lake Biwa and Environment

Kyoto　 Pref 　

Osaka Pref.

Shiga　 Pref 　

Hyogo Pref.

Lake Biwa

Yodo River

Kizu River

Katsura River

Seta-Uji RiverThree Rivers (Set

a-Uji, Kzu, Katsura) make Yodo River

Seta Weir

Lake Biwa and Yodo River Basi

n

Lake Biwa Key FactsSmall, but Largest Lake in Japan (670 km2) Approx. 460 rivers flowing into Lake Biwa Only one outflow from Lake Biwa (the Seta River)Approx.1900 mm precipitation One of the oldest lakes in the world (4 million years)1000 species, incl. more than 50 indigenous species Lake Biwa-Yodo River Basin Key FactsJapan’s second Mega-city area in downstream (Kyoto-Osaka-Kobe) (20 million population)Lake Biwa Basin occupies half of the basin (Yodo River water depends much on outflow from Lake Biwa)Lake water is supplied to 14 million people

Water Flow

Yodo River

8,452 mill. m3/y

Uji River

5,571

Katsura 1,453 Kizu 1,550

Seta Rive

r4,30

2

　 　 WaterDeveloped

　 Average

Annual 　 Down-stream

　 m3/s mill. m3/y ｍ３／ s

Seta River 136 4,302 　 　Uji River 177 5,571 55 54

Katsura River 46 1,453 4 3

Kizu River 50 1,550 13 7

Mainstream 267 8,452 21 21

Biwa-YodoBasin Total

8,240 Km2

Lake BiwaBasin

3,848Km2

Area

Needs in 1950-1960sDownstream area(Osaka, Kobe)

Water Demand for human/industry use to meet population/economic growth

(Land Subsidence by groundwater overuse)Upstream area (Lake Biwa (Shiga))

Lake shore flood was long time problemLake water quality is going to degradedPeople want to use more lake water regional develop

ment (waterworks, irrigation, sewerage, road, etc.)

0

500

1000

1500

2000

30昭和 35 40 45 50 55 60 1平成 6

（万人）Water User Population

1955 1960 1965 1970 1975 1980 1985 1990 1995

20

15

10

5

Mil.

Lake Biwa Comprehensive DevelopmentPlan

(LBCDP)

• 10 year Comprehensive Plan based on a Special National Law: National government endorsement

• Balancing Demands of Upstream & Downstream– Sending more water from Lake Biwa to downstream by lowerin

g the Lake Biwa water level (With Compensation for lowering water level:Port, water intake

renewal, etc.)– Implementing upstream regional development projects at natio

nal and downstream government expense

• Conprehensive program in the areas of Flood Control, Effective Water Use, Conserving Environment in Lake Biwa

LBCDP expenses

Higher subsidy rate of national government i.e. Sewerage subsidy: 1/2 to 3/4 Osaka/Hyogo Governments Pays part of Shiga’s expense 60,200 m. yen total ( 602 m $) Osaka/Hyogo Governments Granted a Loan to Shiga 5,000 m.yen total (50 m. $)

Special Financial Arrangement

Finance of LBCDPProjects by Japan Water Agency(Lake Flood Control, Water development and Water Lowering compensation )

　 351,300 million yen (approx.3,513 m.$)

Projects by Prefectural and Municipal Governments(Other Region Improvement projects)

1,554,243 million yen (approx.15,542 m.$)

　　　　　 Total 1,905,543 million yen (approx. 19,055 m.$)

　 LBCDP Water Made 　 Available in

Upstream and Downstream 　 Area

Water Supply from Lake Biwa

Increase

Increase

Increase

1942 1960 1972 1992

Shiga

Osaka

Hyogo

success

　 LBCDP Water Quality Improvement in Lake Biwa

「琵琶湖の総合的な保全の推進」パンフレット（琵琶湖総合保全連絡調整会議等）

Se

we

rag

e T

rea

ted

po

pu

lati

on

ra

te

%

Sewerage Treated population rate %

BOD of river water flowing into South LakeBOD of river water flowing into North Lake (East Shore)BOD of river water flowing into

North Lake (West Shore)

1985 1990 1995 2000

success

昭和 58年

Kusatsu region, South Shina 2nd area

出典：「淡海よ永遠に　琵琶湖開発事業史」（現近畿地方整備局、水資源開発公団） 

出典：「琵琶湖開発事業現況写真 ] 水資源開発公団

Before dike construction Completion under construction

LBCDP Lake Shore Flood Control

１９６５－１９７４

１９７５－１９８４１９８５－

Houses

Number of houses

inundated above/belo

w floor level

Max. water level

LBCDP’s result Lake Shore Flood Control success

Natural Shore decrease

1953 1992 　 79’ 85’ 91’

Reed belt decrease

Lake Shore DegradationFailur

e

Lake Conservation Programs in 3 areas;

Maintaining and improving Water Quality

Improving Recharge Capacity of Soil

Preserving natural environment and landscape

50 year goal, 10 year action planGovernment programs and Participation by

Stakeholders

Lake Biwa Comprehensive Preservation Plan

(Mother Lake 21 Plan)

Water for EcosystemRestoration of attached lake

which once converted to rice fields

Test introduction of water and monitoring

1955

Present

Future Plan

The land reclaimed for rice paddy is now being planned to be back to the lake. The Experiment to monitor how waterfowls and water plants will be restored by introducing water from lake to the land is being implemented.

Historical “Soap campaign”

Housewive’s campaign to stop using synthetic detergents

Lake Biwa Eutrophication Prevention Ordinance 1979(Japan’s first legislation for controlling inflow of nitrogen and phosphorus)

Red tide occurrence dramatically decreased

Synthetic detergent containing phosphorus exchanged with soap

Lake Biwa Basin Network Committee

Collaboration Sub-basin level Association

Participation by stakeholders at Inflow River Sub Basin level in Lake Biwa Catchment Area

KoseiSub-basin

KonanSub-basin

Otsu-ShigaSub-basin

KokaSub-basin

KoseiSub-basin

HigahiomiSub-basin

KohokuSub-basin

school

Town govt.

Forestrycooperative

Individual

Community Organization

Private company

Conservationgroup

Fisherycooperative

Private company

individual

Yodo River Basinstakeholders

Exotic Fish Increase

Black Bass (Large Mouth Bass) and Bluegill

Major Fish Catch in Lake Biwa

0200400600800

100012001400

H5

H7

H9

H11

H13

H15

H17

t

エビ類モロコ類フナ類

Shrimp

Biwa Gudgeon

Crucian Carp

1993 1995 1997 1999 2001 2003 2005

New Challenge

Hardest Drought in Lake Biwa 1994 (-123cm)Usual 1994 drought

New Challenge

Integrated Lake Basin Management

Management Implications of Lake Characteristics

Integrating nature Everything comes together, and the issues are mostly inseparable.

Long retention time Problems remain long, finding solutions also takes long time, and the changes are gradual and invisible.

Complex response dynamics Everything affects everything else in water, and the ecosystem behavior is unpredictable and uncontrollable.

Lakes contain more than 90% of Readily-Available Freshwater on the Earth’s Surface

Lake provides vast and variety of Ecosystem value

Integrated Lake Basin Management　 (ILBM) is IWRM with Due Consid

erationfor Their Lentic Water Properties a

nd Ecosystem Value

By ILEC

Thank you for your attention.

1. We have to balance water for HUMAN and ENVIRONMENT/ECOSYSTEM needs when we develop water resources

2. Integrated PLANNING and the FINANCIAL framework to implement it is crucial

3. Participation of People in the Basin is important (We need people’s action, and ideas, and their understanding to get support)

4. IWRM is very necessary in lake basin management with due consideration of lakes’ feature. (ILBM)

Key messages – what we learned from

success and failure in Lake Biwa-

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