The doctoral thesis evaluates the potential and development planning of leisure activities on rivers (kayaking, canoeing, rafting, hydrospeeding, etc.). Considering the starting point that the planning of spatial development in the natural environment for the purpose of leisure, sports, recreation and tourism represents a challenge to preserve the values of the environment, ensuring sustainable development, preservation of health and well-being of people, hypothesis is proposed that the segmentation of the core areas for the development of leisure activities of water and riparian area may establish a system of measures for their balanced development. The resarch of Slovenian river space was assessed by a survey questionnaire of motives, significant and disturbing factors for users who spend their free time in paddling activities. The survey results were used for the specification of the basic characteristics of the streams, considered when assessing the appropriateness of river sections for paddling activities on eight Slovenian rivers according to the adjusted method RIVASSlo. A detailed research of the current situation and potential for the development and verification of the hypothesis, was accomplished in a test region of the Soča River in the Upper Soča Vally. The research has shown that it is reasonable to determine river segments, considering the type of activity, and to divide the segments into sections according to morphological features (degree of difficulty) and the location of the entry/exit points, and that the estimate of the suitability of river sections for the paddling activity on individual sections presents a basis for drafting measures to improve individual attributes. We developed a theoretical model concept of the core area management for the establishment and development of waterways for paddling activity, which pursues an aim the conection of spatial, environmental, socio-economic, cultural and other aspects of sustainable development in the river space. In the thesis we have not been dealt with other forms of leisure activities such as fishing or digging with kayaking can also be in conflict and activities on the waters such as navigation, exploitation of water forces, the water supply, water treatment, purification, irrigation, etc., which may affect on the execution of leisure activities.