Evolving Issues toward Improvement ofthe Lake Biwa - Yodo River Basin
Governance
Masahisa Nakamura
Vice President, ILEC Foundation
Professor, Center for Sustainability and Environment, Shiga Universityand former Director, Lake Biwa Research InstituteAdditional Reading Materials
1.

2.

Nakamura, M. (1995) Lake Biwa: Have sustainable development
objectives been met?, Lakes and Reservoirs, Vol.1, No.1, pp3-29,
Lake Biwa Research Institute, Otsu, Japan
Nakamura, M. et al. Evolving History of Lake Biwa and Yodo RiverBasin Management, Hiroya Kawanabe et al. (eds.), Lake Biwa:
Interactions between Nature and People, Springer
Science+Business Media B.V. 2012

Acknowledgement
This Power Point presentation has been prepared making use of theslides presented in earlier ILEC meetings by the following organizations
and individuals of the Shiga Prefectural Government.
Water Policy Dividiosn, Department of Lake Biwa and Environment.
“Towards Integrated Basin Managementin Lake Biwa and Yodo River Basin- Past and Future - : Bridging Upstream and Downstream, Flood Control,
Efficient Water Use and Ecosystem Protection by All Stakeholders”
presented at the International Forum on ILBM-G Project, Kusatsu, 7 Mar.
2007
River Basin Policy Division, Watershed Policy Bureau (Katsuki Matsuno).
“The Evolving History of Lake Biwa Weir”, presented at the ICOLD
Conference, Bali, 4-5 Oct. 2014 (Coauthored by M. Nakamura)Lake Biwa

Kyoto Pref
Shiga Pref

Katsura River

Lake Biwa andYodo River Basin

Seta Weir

Hyogo Pref.
Seta-Uji River

Three Rivers(Seta-Uji, Kizu,Katsura) makeYodo River

Yodo River

Osaka Pref.

Kizu RiverLake Biwa Key Facts Largest Lake in Japan (670 km2)
 Approx. 460 rivers flowing into Lake Biwa, only one outflow fromLake Biwa (the Seta River) One of the oldest lakes in the world (4 million years)
 1000 species, incl. more than 50 indigenous species

Yodo River Basin Key Facts Japan’s second Mega-city area in downstream (Kyoto-OsakaKobe) (17 million population)
 Lake Biwa Basin occupies half of the basin (Yodo River water
depends much on outflow from Lake Biwa)
 Water is utilized many times

Lake Biwa Key Facts• Altitude

85.614 m asl (at low tide in Osaka Bay)• Surface area

670.25 km2(Approx. 1/6 the area of the prefecture)• Shoreline

235.20 km• Catchment area

3,848 km2

• Maximum Length (North-Soutn) 63.49 km
22.80 km
• Maximum width (East-West)• Minimum width (East-West)

1.35 km• Mean depth

41.20 m• Maximum depth

103.58 m• Water volume

27.5 billion m3• Water temperature

Max 29.9C(Jul2004) Min 4.4C(Feb2005)

The Biwa – Yodo Region• Biwako River Office, Kinki Regional Development Bureau, M L I T

Lake Biwa and Yodo River Basin•Lake•BiwaTokyo•WholeBasin Area

Biwa-YodoBasin Total

8,240Km2

Lake BiwaBasin

3,848Km2•Shiga•Kyoto•Kobe•OsakaWater Supply area

Shiga

1,102,737

Kyoto

1,814,201

Osaka

8,772,470

Hyogo

2,667,211

total

14,356,619

Landscape of Lake Biwa - Yodo RiverUpstream(Lake Biwa)•LakeBiwaMidstream(Yodo,Kizu,Katsura River)Downstream(Yodo River and Osaka Bay)

•琵琶湖の水位変化

洪水の歴史記録（Flooding History Record)琵琶湖の大洪水
Lake Biwa Record Flooding (+3.76m, 1896)

1896年の琵琶湖大洪水

Serving for Downstream Needs• First Lake Biwa Canal completed in 1894 ( from1885)• 8.35/sec for Water Supply and Hydropower• Second Lake Biwa Canal completed in 1912 年• Consultative Council for Lake Biwa Comprehensive Development in 1956
• (downstream) water demand increase due to population increase and industrialization•• Anothermajor
Flooding
1917,
Yodomanagement
River Improvement(upstream)
floodcontrolinanddrought
needs: to Start
levy construction and dredging were their desires•Nango Weir at Lake Biwa Mouth• Lake Biwa Comprehensive Development to start in 1972 (up till 1997)
down at Seta River, in 1906

Masahisa Nakamura, Executive Director
and Vice President ILEC Foundation:
RCSE Shiga University

Needs of Downstream
Water Demand Growth•Water User Population from Yodo River•1955 •1960•1965 •1970 •1975

Land Subsidenceby groundwateroveruse•（大阪市水道局蔵）•1980 •1985•1990 •1995

Needs in 1960s
Downstream area(Osaka, Kobe) Water Demand for human/industry use to meet
population/economic growth(avoiding groundwater overuse )Upstream area (Lake Biwa (Shiga)) Flood Control in the shores
 Lake water conservation
 Infrastructures to use lake water and area’s
Development(waterworks, irrigation, sewerage, road, etc.)

The Lake Biwa Weir

Weir History:

Original one (1905)
Rplaced with a new one (1961)
Improved with a bypass(1992)

Land Use Changesin Lake Biwa and the Yodo River Basin
•１９９２
•１９５５

•１８９５Legend
Municipality
Forests
Farm Land
Urban Areas
Undesignated Areas
Water Areas•（Lake Biwa Museum

The Biwa - Yodo - Osaka Bay Basin,
Population Distribution (as of 2018)

Results-1 (Lake Biwa
Comprehensive Development –LBCDP, 1972-1997)

4. WATER RESOURCES AND REGIONAL DEVELOPMENTNEEDS
4.1. Lake Biwa Comprehensive Development Project (LBCDP)
 1972-1997, 25 years Basically for Downstream water needs
4.2. Policy Framework of LBCDP
 Special Law
 Upstream and Downstream Governments Ministry of Construction (then) was the lead agency
4.3. Implementation Schemes of LBCDP Lake Biwa water Level Seta River dredging and Shoreline flood management
 Weir operating principles
 Development of the Yodo River Basin Management Plans

LBCDP viewed as an IWRM
• Integrate Demands of Upstream & Downstream– Sending more water from Lake Biwa to downstream by loweringthe Lake Biwa water level(With Compensation for lowering water level: Port, water intake
renewal, etc.)– Upstream region (Shiga) development by special financial
arrangement including covering cost partly by downstream
governments• Integrate Needs of Flood Control, Water Use, Environment– Diverse water resource area improvement projects in upstream(Shiga)• Integrate Water Conservation Programs in Lake Basin– Afforestation, River Improvement, Sewerage, etc.

Water Quantity Management
AverageAnnualm3／s

mill.m3／y

Seta River

136

4,423

Uji River

177

5,572

Katsura River

46

1,453

Kizu River

51

1,561

Yodo Rivermainstream

267

8,453

SetRiver
4,423
Kizu River 1,561•Katsura River 1,453

Uji River
5,572
Yodo River
8,453 mill.m3／ySoucce: Lake Biwa-Yodo River Water Quality Preservation Organization

Seta River Weir controls the lake water level and the
Seta River flow (only outflow river from Lake Biwa)(built 1905, renewed 1961)

Needs of Upstream/downstream
Water Quality Degradation in Lake Biwa

Transparency
degree (m)滋賀県人口推移•Population of Shiga Prefecture

1,600,000
人
1,400,000
1,200,000
1,000,000
800,000
600,000
400,000
200,000

滋賀県人口推移

01920

1935

1950

1965

1980

1995

New Water Level Control• Utilize water of Lake Biwa down to -1.5m• Give additional 40t/m3 water supply to downstream
Planned High Water Level = +1.4m•+30cm•+30cm•-20cm•-30cm•-1.5mLowest Control•利用低水位-1.5m
Level: -1.5m• Lowest
Control level•6月16日•8月31日•10月15日

LBCDP Features
Coordination of up/downstream’s needs bynational government
 National Project supported by special legislationand long-term plan framework Special Financing Arrangement(National government subsidy, fund transfering from

downstream government to upstream government)

LBCDP expenses

Finance of LBCDP
Projects by Japan Water Agency(Lake Flood Control, Water development
and Water Lowering compensation )Projects by Prefectural and Municipal
Governments(Other Region Improvement projects)
Total

351,300 million yen(approx.3,513 m.$)
1,554,243 million yen(approx.15,542 m.$)
1,905,543 million yen(approx. 19,055 m.$)Special Financial Arrangement
Higher subsidy rate of national governmente.g., 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. $)LBCDP’s results:
Water for the Upstream and Downstream AreasShiga

Water Supply from Lake Biwa
Kyoto

OsakaHyogo

1942

1960

1972

1992

LBCDP’s results
Lake Shore Flood Control•Kusatsu region, South Shina 2 nd area

Before dike construction

under construction•昭和58年•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

Completion

Water Supply and Sewerage for Downstream

Masahisa Nakamura, Executive Director
and Vice President ILEC Foundation:
RCSE Shiga University

Irrigation and Drainage

Masahisa Nakamura, Executive Directorand Vice President ILEC Foundation:
RCSE Shiga University

Variety of Sewerage Systems

Masahisa Nakamura, Executive Director
and Vice President ILEC Foundation:
RCSE Shiga University

LBCDP’s result
Environment conservationin Lake Biwa area

Konan-chubu
Sewage Treatment
Plant

LBCDP’s result
Water Quality Improvement in Lake Biwa
•Sewerage Treated population rate %Sewerage Treated population rate %BOD of river water flowing into South Lake
BOD of river water flowing into North Lake
(East Shore)
BOD of river water flowing into North Lake(West Shore)

1985
出典19901995

2000「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）

Outcome of LBCDPin Flood Control and Water Use

Level ofLake Biwa•Minimum
Water Level ofLake Biwa

• Water•No. of daysof Inundation• Lake Biwa Development Integrated Operation and Maintenance Office, Japan Water

LBCDP did achieve its major objectives.

On the other hand,

there have been massive transformationsin the watershed and lakeshore that led tosignificant ecosystem deteriorations.

Reason 1

Reason 2

Impacts on
Lakeshore Habitats

Before 1992

Change in WeirOperations

After1992

Result 4
Result 4

Declining
Fisheries

漁獲の減少 (Declining
Fisheries)

InvadingSpecies
外来魚の侵入 (InvadingSpecies)

Reason 3

Masahisa Nakamura, Executive Directorand Vice President ILEC Foundation:
RCSE Shiga University

Reason 4

Reason 5

Result 6

Reason 7

Result 1

Result 2

Result 3

Macrophytes (Water Plants) Infestations

Exotic Fish Increase•http://www.isewan-db.go.jp/ise-kankyo/img/B1g/akashio.jpg

“Soap campaign”

Housewive’s campaign tostop using syntheticdetergents•Lake Biwa Eutrophication Prevention
Ordinance 1977(Japan’s first legislation
for controlling inflow of nitrogen andphosphorus)

Phosphrus-containing
detergents exchanged
with soap
Red tide occurrencedramatically decreased nextyear

Composition of Pollutant Source•Groundwater•Rainfall to lake
•Forest•Urban land, Road•Agricultural land
•Livestock farm•Industry•Household•Non point•source•Point•source
•

１９８５

１９９０

１９９５

２０００２００５

Needs for Dedicated Conservation Efforts
Lake Biwa Comprehensive Conservation Plan(LBCCP, 2000-2050)
First 10 Years

Emphasis on “ecosystem restoration”
 No special national legislation
 Downstream governments reluctant to fund projects
Toward Next 10 Years

Toward greater societal engagement
 The second phase plan (2011-2020) needs to be improved
to meet the emerging needsLake Biwa Comprehensive
Conservation PlanLBCCP to Facilitate Greater Efforts in Pursuing the Human - Ecosystem Balance Integrating Lake Watershed (River Basin) Management
 Advancing Monitoring and Treatment Technologies
 Enhancing Broader Stakeholder Participation

Ensuring the Plan’s Effectiveness• Flexible Execution– Reflecting observations, surveys, research, andtechnological development– Reflecting plan progress and assessment– Coordinating groups and measures– Considering institutional reform
Plan Mechanisms (for continuous improvement)•Implementation•Rebuilding•ManagementMonitoring andEvaluation

Lake Biwa Leisure Use Ordinance, 2002

Rule

１

Regulate Motored Pleasure Boats

Rule

２

Prohibit 2-cycle engine jet ski

Rule

３

Prohibit Releasing exotic fishPromoting Shiga
EnvironmentalFriendly
Agri-products

Fish Cradle Project
Restoration the lost watercourse between lake and rice
field for fish spawning•背景１水田Branding
Fish Cradle - Paddy Rice

Ecosystem Protection
Reclaimed Attached Lakes to be Restored Back
•The land reclaimed for rice paddy is
now being planned to be back to thelake. The Experiment to monitor how
waterfowls and water plants will be
restored by introducing water fromlake to the land is being
implemented.

1955

Present• Future Plan

New Challenges after LBCCP

Facility Maintenance and Risk Management• Less attention and no special legislation formanagement (compared to construction)• Less population/tax to cover cost
• Risk control (earthquake, etc.)
Climate Change• Possible more frequent flood/drought• Dissolved oxygen decrease in Lake bottom

Risk management against
earthquake•Biwako west
Fault Vein

•Damage in Treatment center in Kobe (1995)•KonanChubuTreatment

Climate Change in Lake Biwa area
•Rise ofTemprature•Decrease of rainfall•琵琶湖河川事務所HP

Hardest Drought in Lake Biwa 1994 (-123cm)•Usual•1994 droughtDecrease of Dissolved Oxygen in
the Bottom in Lake Biwa

In usual years, surface water is cooled down in winter and sinkdown and mix with bottom water, then oxygen is supplied tothe bottom water.
In 2007 winter, this water circulation did not happen until April.

Spring to Summer

phyto plankton•植物プランクトン•酸素
oxygen•barrier
layer
•水温躍層

Oxygen Consumed in Bottom

Winterphytoｐlankton•植物プランクトンoxygen•酸素•全循環ｃirculation

Oxygen Supplied to Bottom

Strong Connectionsin Lake Biwa and Yodo River Basin- Past and Present Human life, industry,and Transportation
based onwater resource
History and Culture•related to water

Unified urban area
developed riparian area

Conflict on Flood Control
and Water Use
Various project implemented
on Flood Control,
Water Efficient Use andEnvironment Conservation

Advanced strategy
introduced, e.g.,
LBCDP, Mother Lake 21

Future of Lake Biwa Yodo and River Basin
Lake Biwa’s StrongConnection WithYodo River Basin
Problems of Lake Biwa
cannot be solved
only within
Lake Biwa Basin Degradation of Water Qualityand Ecosystem
 Loss of original landscape Weakening of relationshipbetween human and water Declining of urban vitality
Lake Biwa andYodo River
sharescommon problems

Movement to prefectural
government system
restructuring forlarger area governanceWe need Integrated Basin Managementin Lake Biwa and Yodo River BasinWater Quality in Lake •Konan-chubu
Biwa Sewage
Treatment Plant•Takashima Sewage
Treatment Plant•challenge•Tohoku-bu Sewage
Treatment Plant

THE CHALLENGES AHEAD (Emerged PolicyFrameworks)
Yodo River Improvement Plan, 2009
Integrated Management Lake Proposed
Conceptual Framework, 2011
the Kansai Broader Region Collaboration
Framework, 2012
Passing of the “Basic Law for Circulatory
Management of Water”, necessitates the Biwa –Yodo region to develop a “Basic Plan for
Circulatory Water Management”, 2014

Water Use in Lake Biwa-Yodo River Basin
Prefecture

Water supplied
population from Lake
Biwa (persons)Shiga

1,148,702

Kyoto

1,811,645

Osaka

8,817,876

Hyogo

2,757,285

SUM

14,535,508•Sumitomo et. Al, Environmental & sanitaryengineering research, Vol.12, No.3, 1998

Increasing Water Contamination
RisksComplicated andhighly reused watersystem

Increasing of tap watercontamination risks by•micro-pollutant andmicrobe• Sewage Treatment Plant Drain• Tap Water Intake

Source: Lake Biwa-Yodo River Water Quality Preservation Organization

Then Need for Broader Basin Governance involving
Lentic – Lotic systems consisting of the entire Lake
Biwa, Yodo River and the Osaka Bay region

Lentic Water Systems
ex. Lakes, Reservoirs, Ponds,Wetlands etc.

•Lentic and Lotic Water Systems in Yodo River Basin and Lotic Water Systems, ex.
Osaka Bay Region
Rivers, Canals etc.