The book is designed to elaborate some causes of flood which happened in Medan City, Indonesia. Flood is something very horrible by people leaving in Medan city. Flood can cause many negative things for human live such as dead, illness, poverty and so on. With the implementation of conservation, this negative effect can be minimized. In order for the conservation directives for flood control of the results of this study to be practicable, it is necessary to socialize to all relevant stakeholder elements, both at the community level and the government agencies or agencies that are competent with flood issues. There needs to be socialization regularly and programmed by stakeholders from government, non-governmental organizations, private sector about the importance of watershed and the application of conservation rules in watershed, so that people can play an active role in watershed management. To maximize the results of the study there needs to be an economic, socio-cultural analysis of the community in relation to the contribution of the community to the factors of increasing the potential for flood as well as their role factors in river conservation.