Initiatives for water environment
conservation in lakes of Japan: Caseof Lake Biwa
Presented by WEPA Secretariat
at the Consultation Meeting on theWEPA Action Programme
11 December 2019
Phnom Penh, Cambodia

About Lake Biwa
 About Lake Biwa
 History of development of Lake Biwa
 Importance of Lake Biwa
 Demographic and land use change Changes in Lake Biwa
 Reports of water quality deterioration
 History of water environment management conservation of LakeBiwa
 Actions towards the water quality improvement in Lake Biwa andresults
 Lake Biwa comprehensive conservation plan and specific measures
 Coordination framework of of the Lake Biwa comprehensive
conservation initiatives

About Lake Biwa

 The third oldest lake in theworld (4 million years)

 The largest Lake in Japan (670km2), nearly same size ofPhnom Penh
 Entirely located in Shiga
prefecture Water volume: 27.5 billion m3

 Mean depth: 41m
 Maximum depth:103.58m

History of development activities of Lake Biwa area

Expanded farmland

Industrial andeconomic
development

Rice cultivation
introduced

Edo period
1603-1868
Yayoi period
300BC-300AC

After Meiji
restoration
1868

Importance of Lake Biwa in socio-economic
development and environment• Major source ofdrinking water for
more than 15
million people inthe region• Center of cultureand traditions• Receives water flows
from more than 400
rivers or streams• Habitats to more than
1000 species

Economic• Main source of water for industries andagriculture in the region• Source of freshwater fisheries• Tourism

Pattern of land use change in Lake Biwa and Yodo
River basin
NWES

1895

1992

Rapid urbanization

Population density distribution in Lake Biwa
catchmentReports of water quality deterioration of Lake Biwa

Complaints of musty
odor in tap water werefiled in Kyoto City.

Fish in the lake
contaminated by PCP
from agriculture

1960

Blue-green algae blooms
spread over southern lake
for the first time.

1983

1994

1977
1969
Uroglena (vegetableplankton) spread overthe lake

Blue-green algae
blooms spreadover northern lake
for the first time;

History of water environment
conservation of Lake Biwa
Shiga Prefecture
enacted Lake Biwa
Eutrophication
Prevention OrdinanceLake Biwa
ComprehensiveDevelopment
PromotionCouncil wasestablished.

Designated as thefirst quasi nationalpark of Japan

Lake Biwa Water
Quality Conservation
Plan was finalized

1997
1987

Mother Lake 21Plan

1999 2000

1982
1979
1972

Established Lake Biwa
Research Institute1970 • Environmental standard
1950

management

was introduced to LakeBiwa• Lake Biwa comprehensive
Development Project

Establishment of Lake Biwa
Comprehensive Preservation
Liaison Coordination andLake Biwa Comprehensive
Preservation Promotion
Council
Action Plans for Conserving
Water Quality of Lake Biwa
were finalized.

Actions towards the water quality improvement in Lake
Biwa: Soap movement initiated by local residents
Campaign to stop phosphorus contained synthetic household soap

Decrease inoccurrence ofred tideOverview of Lake Biwa Development Project (19721997
Purpose:– To develop additional water resource for the downstream– To reduce the threat of floods– To restore the water quality of Lake Biwa
Budget and Activities:

19.05 billion USD

LBCDP’s results: Water Quality Improvement in Lake
Biwa

LBCDP’s results: Water Quality Improvement in Lake
Biwa
Total-P

LBCDP’s results: Water Quality Improvement in Lake
Biwa
Total-NObjectives of Lake Biwa comprehensive conservation
planReduce pollution load tolevel of later half of
1960s
COD: reduce by 31%
T-P: 36%
T-N: 17%

Restoring water quality
to level of later half of
1960s

Securing sufficient land
area
inforest,
agriculture and urban
for rainfall infiltration

Developing eco-friendly
lifestyles and building
Lake Biwa conservation
networks
1st Phase
1999

Desired state of lake
Biwa

Improve and sustain soil's
rainfall filtration andholding capacity inforests, farmlands andurban districts• Increasing publicinvolvement• coordinating effortsof related governmentalorganizations

2nd Phase2010• Water quality return tothe level of the late1960s• Make full use of watercycle• Rich environmental
ecosystem

Long-term
2020

2050

Specific measures for water environment conservation ofthe Lake Biwa

Advanced sewage
treatment plant

Purification of
rainwater in urban
districts

Circulatory irrigation
systemForest management

Dredging of Lake Bottom

Permeable Pavement andUrban Green Zones

Coordination framework of the Lake Biwa comprehensive
conservation initiatives

Cooperative Structure of Prefectures in the Lake Biwa Catchment
Governments

Citizens

Citizens

Cooperative Structure in the Lake Biwa - Yodo River Watershed(Lake Biwa Comprehensive Preservation Promotion Council)

Lake Biwa Comprehensive Preservation Liaison Coordination Council

MHLW

MAFF

MLIT

MOE

FoA

FiA

Thank you very much