Water from the Batang Toru forest is vital for communities, a majority of whom still use river water for all daily uses. Some of these watersheds only have 5-14% forest cover left. Although in a critical state, these watersheds still provide water for the bulk of people living in Central Tapanuli.
The catchment containing the second largest percentage of the forests is the Sipansihaporas catchment that supplies water to an important hydroelectric powerplant (50MW) downstream. This watershed is still mostly forested although encroachment by immigrants is a serious threat.
The catchments containing the smallest percentage of the forests are the Badiri, Tapus and Pandan catchments, which have been largely deforested, particularly in the last 15 years due to encroachment by migrants.
The majority of the forests (64%) lie in the largest water catchment of the region, the Batang Toru river. The upper catchment area of this river to the north of Tarutung is already largely deforested, and the Batang Toru forests are the last forests protecting its hydrology. There are plans currently to build a 550MW hydroelectric scheme where the Batang Toru River passes through a key forested area of the Ecosystem.
Water from the Batang Toru forests is vital for communities, a majority of whom still use river water for all daily uses. In addition, large rice fields in the Sarulla valley rely completely on water from this forest, as well as the larger rubber and oil palm plantations towards the coast in Central and South Tapanuli.
High rainfall (4,879 mm in 2016) in the Batang Toru area supports a steady waterflow important for agriculture, plantations, household use, as well as hydropower, and potential geo-thermal development in the future. On the other hand, such high rainfall greatly increases erosion and the chance of landslides, especially in deforested areas.