Water resources management of Toba lake and its isotopic implementation

Toba Lake has long been known as a part of life cycle of the people living around the lake. More importantly, the lake water is also used for generating hydroelectric power of 520 MW effective capacity. Catchment area of the lake which is 3450 km2 plays an important role to sustain the water balance, in addition to meteorological factors governing the ecological system of the studied area. Mentioning the beautifulness landscape of the Toba Lake, it bus become a very important factor for tourist destination area which in turn, to a certain degree has contributed to the source of our national income. Taking into consideration those factors, it is easy to understand that any disturbance to the lake water either by human activities or by nature, it will arise to some problems, and, therefore, need to be solved