Lake Toba Profile: a UNESCO Global Geopark

Lake Toba profile is colorful and magnificent. Firstly, it is home to a diverse range of geological features, including hot springs, waterfalls, and unique rock formations. It is also home to a variety of plant and animal life, including many endemic species. Secondly, it represents the unifying geosite within the Toba Caldera UNESCO Global Geopark. The caldera has transformed into a beautiful lake by containing water from the surrounding area. Thirdly, the lake is the largest volcanic crater ever in existence. Lake Toba has a surface area of 1,130 square kilometers (436 sq mi) and a body length of 86 kilometers (53 mi). The series of volcanic eruptions with the last one taking place 74,000 years ago left a large caldera that was later filled in with 240 cubic kilometers (57.6 cu mi) of water. The blue water and green vegetation of the lake have attracted inhabitants as well as tourists.

Lake Toba is currently developing into a world-class tourist destination. It ranks 1st on the list of New Bali. Under the New Bali plan, the Indonesian government wants to leverage the success in Bali to boost visitor traffic to a handfull of other destinations, most notably Lake Toba. But, the lake has long been a favorite destination for tourists worldwide. The recent development focuses on building new roads, new hotels, new resorts, and new attractions.

New Roads

Lake Toba profile represents a growth area. The goverment is spending significant resources to develop infrastructure and new roads. For example, land access to the lake area has recently improved with some key road constructions. The roads under construction are the freeways (toll roads) connecting Medan and Parapat. When these are done, the land transfer from the capital city to Lake Toba will reduce from 4 hours to 1.5 hours. To see the current status of ground access to Lake Toba, check it out on the map here.

In addition, there is the preservation and widening work of Jalan Pangururan-Ambarita-Tomok-Onan Runggu (77  km/50 mi), Jalan Tele-Pangururan-Nainggolan-Onan Runggu (69 km/42 mi), and Jalan Tebing Tinggi-Pematang Siantar-Parapat (110 km/68 mi). However, all of these roads are within the lake area. Lake Toba will also see a new Tano Ponggol (currently 95% completed), the only bridge connecting the mainland with Samosir Island.

Samosir Island

Lake Toba profile is also cultural. There is an island in the middle of the lake called Samosir Island. It is famous for its Toba culture and tradition. Samosir boasts the history of ancient human. For instance, there was a king who beheaded criminals and took their blood as his drink. The court chairs where he would render his decision still exist today. Similarly, the execution table where his men would execute the villains is still intact. Come and enjoy the stunning beauty of the lake and the distinctive culture of its inhabitants (see Lake Toba People and Culture).

Geological Profile

Lake Toba profile is geological, too. It is made up of four overlapping volcanic craters that adjoin the Sumatran volcanic front. The youngest one is the world’s largest Quaternary caldera. The caldera has a length of 86.15 kilometers (53 mi) and a width of 30 kilometers (18.6 mi). It intersects the other three. Below is a summary of Lake Toba profile from the geological point of view.

NAME Lake Toba (Danau Toba)
COUNTRY Indonesia
SURFACE AREA 1,130 km2 (436 sq mi)
MAXIMUM DEPTH 529 m (1,736 ft)
AVERAGE DEPTH 213 m (699 ft)
LAKE TYPE Volcanic
LENGTH 86.15 km (53 mi)
WIDTH 30 km (18.6 mi)
CATCHMENT AREA 3,726 km2 (1,439 sq mi)
ALTITUDE 900 m (2,953 ft)
VOLUME 240 km3 (57.6 cu mi)
OUTFLOWS Asahan River
SHORE LENGTH 464 km (288 mi)
AGE 10,000 – 100,000 years
MIXING TYPE Homogeneous
FREEZING Never freezes
RESIDENCE TIME 20,777 days
FISH SPECIES Catfish, tilapia
TROPHIC STATE Oligotrophic (nutrient-poor)
ORIGIN Volcanic
AVERAGE DISCHARGE 134 m3 (4,730 cu ft)/ second


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