ABSTRACT Hydrological modeling is one of the important methods in supporting water resources management, especially in river basins (DAS) that have complex characteristics such as the Rokan Hulu DAS. This study aims to apply the HBV (Hydrologiska Byråns Vattenbalansavdelning) hydrological model using the HBV-Light software in modeling flow discharge in the Rokan Kiri Sub-DAS, Lubuk Bendahara …