While local governments implement various policies related to urban development and regeneration, welfare, culture and tourism, the river space, in particular, which river managers designated as water-friendly space, provides residents with opportunities for their relaxation and leisures. As a local resource, the value of the space continues to increase.
Hence, river managers recently recognized necessities to manage and operate the river space in accordance with visitors’ demands, and to examine usefulness in applying mobile big data to improve the understanding of visitors’ demands. In these regards, the authors first validates the number of visitors obtained from mobile big data with several water-friendly space cases. The accuracy of mobile big data turns out to be quite good enough to significantly reduce river managers’ burdens in field surveys, although it remains to be improved further. By using various information that can be inferred with the data, the authors then define eight water-friendly space indicators. Those indicators seem very useful to understand how residents interact with river spaces. With all results, authors conclude that mobile big data and defined indicators have potentials as valuable data sources for river managers’ practices, especially, in making decisions upon classification of water-friendly space, establishment of convenient facilities, optimization of O&M budget, and deregulation on the river space use permission system.