Following the successful development of hydropower facilities in Indonesia, a new project was established to study the potentials for the development of a hydro-electric power plant in the Tripa Basin, North Sumatra, Indonesia. To make a go/no-go decision of a more detailed feasibility study, a pre-feasibility study is undertaken to the expected flows at the intake of the proposed Tripa hydro-electric powerplant. Expected flows are analysed by means of hydrographs, flow duration curves that serves as a basis for economic feasibility studies to the hydropower plant capacities, and on the frequency of potentially occurring floods.

The project should turn this renewable energy opportunity into a source of economic empowerment for the region and a sustainable source of electricity for the people living in North Sumatra. A pre-feasibility study is undertaken to the expected flows at the intake of the proposed Tripa hydro-electric power plant to indicate whether a more detailed feasibility study is feasible.

For the analysis of the expected flow at the intake a hydrological model, called HEC-HMS is used. This hydrological model simulates rainfall-runoff at any point within a watershed given physical characteristics of the watershed. The model is freely available, somewhat less data demanding, and easy to apply. The outputs of the model are analysed by means of streamflow hydrographs, and flow duration curves that serves as a basis for economic feasibility studies to the capacity of the proposed power plants. In addition, flood flows with recurrence intervals up to 10.000 years are analysed.