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Toba (Danau Toba)
General Information
| Description |
Lake Toba, the largest year-round lake in Southeast Asia, is located in the province of North Sumatra, Indonesia, approximately 176 km to the west of the provincial capital, Medan. It is the largest volcanic lake in the world. |
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| Country |
Indonesia
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| Latitude |
2° 30' 0"
(2.5000) |
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| Longitude |
99° 0'
0" (99.0000) |
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Maps
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Toba global index map
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Largest Lakes of the World by Volume (LakeNet Explorer 2004)
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Toba locator map |
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Toba Watershed and Adminsitrative Boundaries (LakeNet)
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Lake Basin Management Initiative (LakeNet Explorer)
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USAID-supported Lake Basin Management and Biodiversity Conservation Technical Assistance 2003-2004 (LakeNet Explorer)
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Physical Characteristics
| Description |
Toba's origins are tectonic and volcanic. The lake was formed as a consequence of the largest volcanic eruption ever to occur on earth, approximately 75 000 years ago, which ejected some 1 500 to 2 000 km3 of material. Dust and other volcanic material reached as far as Sri Lanka and the Bay of Bengal. At some locations in the vicinity of Lake Toba, tuff layers as thick as 600 m can be found. In comparison, the largest recent volcanic explosion, Mount St. Helens, which erupted in 1980, produced 2.3 km3 of material. Additional eruptions approximately 30 000 years ago created the island of Samosir in the middle of Lake Toba. (Lehmusluoto et al. 1999). The lake is approximately 90 km long and is situated approximately 900 m above sea level. The lake catchment area is approximately 43% hilly and 30% mountainous, with peaks more than 2 000 m above sea level. Average rainfall is more than 1 500 mm annually, and temperature fluctuates between 19°- 20° C. Of the 202 brooks and rivers that empty into the lake, only 70 run year-round. Studies suggest that the inflow of water into the lake is decreasing. In the period 1920-1932, average inflow was 110 m3 s-1, which decreased to 104.4 m3 s-1 in 1957-1975 and to 90 m3 s-1 in 1976-1988. |
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| Volume |
240.00 km3 |
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| Surface Area |
1,103.00 km2 |
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| Depth |
Maximum depth: 505.0 m
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| Age |
10,000 - 99,999 years before present
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| Origin |
Volcanic
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| Trophic State |
Oligotrophic |
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| Type |
Fresh
Permanent
Natural
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| Catchment |
Catchment size: 3,658.00
km2
Catchment/surface area ratio: 3:1 |
Socio-Political
| Economic Value |
The unique geographical position of Lake Toba reserves a number of economic potentials for the benefit of the wide range of communities, especially as a source of bountiful fresh water and lust tropical forest which attract the interest of big industries to invest in the areas. |
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| Primary Economic Sectors |
Agriculture - 64%
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| Major Cities |
Medan |
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| Population |
517,050 (0) |
Watershed Management
| Description |
Administratively, by far the largest part of the Lake Toba water catchment area (87%) is situated in the North Tapanuli District (Kabupaten, or Regency), with the balance divided among the regencies of Simalungun (8.4%), Karo (2%) and Dairi (2.5%). Naturally the North Tapanuli District also houses the largest part (81%) of the total 517,050 inhabitants of the Lake Toba water catchment. The same district has also the highest population density, with 185 people km-2. |
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| Sub-basin Action Plan |
Developed |
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| Issues |
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| Invasive Species |
Moderate Impact |
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| Other Issues |
Aquaculture
Hydropower
Point source pollution
Polluted runoff
Toxics
Watershed habitat alteration
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| Specific Contaminants |
Pathogens
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| Monitoring |
No systematic monitoring program is in place. |
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Biodiversity Conservation
| Description |
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| Designations |
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| Species of Concern |
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Organizations
LakeNet Programs
Documents
Resources
News
Additional Data Sources
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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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Herdendorf, C. 1982. Large lakes of the world. Journal of Great Lakes Research 8:379-412. |
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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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