Aristi, SwaryMudjiatkoRinaldi2013-07-152013-07-152013-07-15rio andikahttp://repository.unri.ac.id:80/handle/123456789/4290Flow patterns and mining river materials can cause the material balance of the river and therefore contribute to the changes in river morphology. Changes in river morphology can cause the river to become deeper due to base erosion and can cause widening due to cliff erosion. Software Surface-water Modeling System is used to determine the flow patterns and velocity distribution that occurs in Kampar river. The value of the velocity distribution of simulation result, when compared with the conditions measurement result, have the same tendency which is the side turn out speed value is smaller than the inside of the turn. This means helicoidal forces acting on the bend of the river is reduced. This is because the ratio of the river depth and the width (h / B) which are small and the bed roughness effect are more dominant than the helicoidal forces that are acting on the turn. According the phenomenon above, it can be concluded that the Kampar river morphology changes with the occurrence of catastrophic landslide cliff and the deepening of the river tends to be caused by the movement of the bed material. The movement of this material will lead to decreased stability of the the river bank as a result of the mining of the river materialsotherVelocity distributionhelicoidal forceslandslide cliffsthe flow patternstudent Paper Post Degree