Riversin Croatia can be divided in few ways: according to counties, catchment areas of the river, larger geographic areas, terrain and hydrological characteristics. Still, each one of these divisions are partially artificiall. Rivers have had an impact on terrain shaping, climate conditions and on specific habitats with complex ecological system. It is necesssary to have a certain knowledge in order to take care of the rivers properly and also to meet the human needs for rivers. Rivers are useful for producing electrical energy, transport and tourism. Above all, rivers are inhabited by diverse flora and fauna. A large number of endemic species are found in the area of our rivers, and insufficient knowledge of these species leads to their inadequate protection in nature. Man by his actions can adversely affect the flora and fauna of the rivers. Analyzing textbooks from Science and Social Studies it is observed that there are a small number of curricula and lectures related to the living creatures of water streams. Integrated day devoted to the theme of Living world in waterstreams is created as important tool to raise the environmental awareness of the importance of protecting these waters and living beings in them and generally environmental protection from an early age. Through various activities, younger school children have learned about the diversity of the living world and the importance of the rivers.