The site
Regal Springs have operations at multiple locations in Indonesia and also in Mexico and Honduras. The focus on this case study is the company operations in Lake Toba, Sumatra.
Lake Toba is Indonesia’s largest lake and the largest volcano-crater lake in the world. It is 87 km long in the northwest to southeast direction and has a width of 27 km. Located 904 m above sea level and with a maximum depth of 505 m Lake Toba is also one of the deepest lakes in the world (Moedjodo et al, 2003). The lake water area is significantly lower than suggested by the overall dimensions however, as a large area of the centre is occupied by Samosir Island.
The Lake Toba catchment area covers 3,658 km2, of which the lake surface accounts for 1,103 km2. The remainder of the catchment area can be classified as hilly (43%) and mountainous (30%), with peaks over 2,000 m above sea level. The latitude and longitude of the lake water area range between E 98° 30'; S 3° 05' and E 99° 20'; S 2° 40'. The surface water temperature ranges between 24° and 27.6°C. Whilst there are 12 major and several minor rivers draining into the lake, there is only one discharge from Lake Toba through the Asahan River. This has a flow rate of up to 102 m3 /second depending on season (Moedjodo et al, 2003).
The Lake Toba operating company, PT Aquafarm Nusantara, has five cage sites and a logistics hub at Ajibata. The following table depicts the number of PT Aquafarm Cage and site locations (data from 2012, water depth taken from Chesner, 2011).
The basic selection criteria for the sites was:
- min. 200m from the shore
- min. water depth of 40m
- away from agricultural activity
- close enough for logistics and transport
- away from local water transport routes
- location protected against strong winds
Cages are arranged neatly to facilitate activities and control. The
distance between cages is determined through considerations for
water circulation to ensure oxygen supply and regard to boat access
for feed, husbandry and harvesting.
The map above visualizes the catchment area of Lake Toba. The area is known for its stunning scenery and the unique Batak culture. Abundant freshwater and dense tropical rain forests in Lake Toba and its surrounding areas provide livelihood for settlements in the area.
