The economic development of Pekanbaru city very rapidly followed population increase that originated from Siak river region. There is an old mosque in this area that is masjid raya Pekanbaru which is history evidence of Raja Siak into the early growth of the Pekanbaru city. Till now Siak River is still importan role life of Pekanbaru community. This can be seen from the development of community activities along the Siak River area and the number of people living along the Siak River .Potential Siak River is fishingplace , clean water resources through PDAM Tirta Siak Pekanbaru , water attractions, with an average depth of 29 m and total length of 572 km and width of 75 - 100m Siak river is able to support the transport system of water with intensity high both for the freighter and passenger ships.Watershed area ( DAS ) has impacted by increase of population in Siak river , which serves for the cultivation and production forest , the area of smallholdings, residential areas , agricultural areas, and the agricultural area of wetlands is only a fraction of forestareas. This research approach is rationalistic qualitative method . Presentation of this research is descriptive , the results of the analysis showed some type of community activities of Siak riverbanks are divided into two (2) types of activity , waste bins and toilets ( MCK ) Siak river . Siak riverbanks impacted by this activities.