The availability of water in the Sub DAS Kampar Kanan which has an important role in addition to being a catch for the Kampar river as well as where the PLTA Koto Panjang hydropower reservoir is located. The hydrological model to be used is the GR4J Model (Genie Rural a 4 parametres Journalier) developed by Perrin, and IHACRES model developed at Australian National University (ANU). The GR4J mo…