Nanase River is an urban river which flows from east to west in the south-eastern part of Kyoto City, joining Higashi Takase River of the Yodo River system. A some 2.9 km long section in the upstream of the confluence with Higashi Takase River is designated as a Class A river. The safety level of flood control for Nanase River was generally low throughout the river, resulting in frequent flood damage. Local residents strongly requested fundamental improvement and the work to create a two-tiered waterway, the second of such type nationwide, took place since FY 1992 as an urban infrastructure and river improvement project.
For this Nanase River improvement project, an integrated approach combining the construction of a flood prevention facility and riverfront improvement with town development was adopted to create a safe and charming living environment with rich water and greenery. The two-tiered waterway section stretches some 950 m in the upstream of the confluence with Higashi Takase River. The lower channel is responsible for flood control in the basin, acting as a flood control facility channelling flood water safely. The upper channel provides a greenery-rich waterfront and is used as places for the relaxation, recreation and interaction of local residents.