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Biwa (Biwa-ko)
General Information
| Description |
Lake Biwa is one of less than 20 ancient lakes in the world. Biwa's ancient beginnings mean species have had millions of years to evolve into new & unique species that exist nowhere else in the world. Biwa is the largest lake in Japan. |
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| Country |
Japan
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| Latitude |
35° 15' 0"
(35.2500) |
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| Longitude |
136° 4'
0" (136.0667) |
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| State |
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Maps
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Biwa global index map (LakeNet Explorer)
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Biwa locator map |
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Ancient Lakes of the World |
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Lake Basin Management Initiative (LakeNet Explorer)
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Physical Characteristics
| Description |
Lake Biwa is located in the upper reaches of the Yodo River Basin. More than 400 tributaries flow into the lake; only the Seta River flows out. |
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| Volume |
27.50 km3 |
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| Surface Area |
670.00 km2 |
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| Depth |
Mean depth: 43.0 m
Maximum depth: 104.0 m
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| Age |
2 million - 20 million years before present
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| Origin |
Tectonic
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| Type |
Fresh
Permanent
Natural
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| Catchment |
Catchment size: 3,848.00
km2
Catchment/surface area ratio: 6:1 |
Socio-Political
| Economic Value |
Lake Biwa is a source of drinking water for 14 million people. The annual fish catch from Biwa is about 3,320 tons. (1997) Over 37 million people visit the lake each year. According to the Environment Agency of Japan, 7.8 million people and US$50,000 million worth of assets would be under the threat of flooding without Lake Biwa to act as flood control. |
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| Major Cities |
Shiga, Kyoto, Osaka |
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Watershed Management
| Description |
Lake Biwa is one of ten lakes designated under the Clean Lakes Law that must put together water quality conservation works and policies and gain the prime minister's approval for a management plan. The prefecture government has 43 people netting invasive fish eight hours a day; in addition, commercial fishermen are paid by the weight of their invasive catch. |
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| Watershed Action Plan |
Developed |
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| Issues |
Invasive black bass and bluegill fish threaten native crucian carp and eels. Large outbreaks of Elodea and Egeria have occured in Biwa from the 1960's onward. Since 1992 a freshwater mussel (Kawahibari-gai) has been found in the Biwa-Yodo River system. These mussels are known to attach to the inside of water pipes, interfering with water flow. Black bass are another invasive species threatening Biwa's native fauna. |
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| Other Issues |
Invasive Species
Lake Levels (water quantity)
Nutrient pollution
Polluted runoff
Sediment contamination
Toxics
Watershed habitat alteration
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| Specific Contaminants |
Mercury
Pesticides
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| Monitoring |
Launched, as a resolution to the conflicts as well as a tool for local economic and water resources development, was the Lake Biwa Comprehensive Development Project (LBCDP), the largest water resources development project in Japan. Meanwhile, the environmental administration, particularly on water environment, of Shiga Prefecture, for which the conservation of Lake Biwa is the top-priority, has always led the one of the central government. Environmental consciousness of Shiga people for the lake gave birth to the Soap Movement, the most successful citizens' movement in Japan, and enabled the prefectural government to enact the Eutrophication Control Ordinance, the very first act for eutrophication control in Japan. |
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| Monitoring Programs |
In-Lake
Water Quality
Biological Resources and Habitats
Lake Use
Tributaries/Watershed
Water Quality
Biological Resources and Habitats
Land Use
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Biodiversity Conservation
| Description |
Lake Biwa is home to 12 indigenous fish species and 20 indigenous types of shellfish. Biwa has 16 species of phytoplankton and 16 species of zooplankton. |
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| Designations |
LakeNet Biodiversity Priority
Ramsar Site
WWF Global 200
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| Ramsar Site Name |
Biwa-ko |
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| Ramsar Designations |
1, 4, 5
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| Species of Concern |
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Organizations
LakeNet Programs
Documents
Resources
News
Additional Data Sources
| • |
Birkett, C., and I. Mason. 1995. A new global lakes database for remote sensing programme studying climatically sensitive large lakes. Journal of Great Lakes Research, 21 (3) 307-318. |
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Duker, L. and L. Borre. 2001. Biodiversity conservation of the world's lakes: a preliminary framework for identifying priorities. LakeNet Report Series Number 2. Annapolis, Maryland USA. |
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International Lake Environment Committee, the United Nations Environment Program and Environment Agency, Government of Japan. 1997. World Lakes Database. |
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Ramsar Convention on Wetlands. The List of Wetlands of International Importance. |
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