七隈川

Gazing at the gentle flow of the Nanakumagawa, have you ever wondered about its journey through Fukuoka? This seemingly tranquil river, known as the Nanakumagawa in Japanese, holds a fascinating tale of transformation and resilience. The Nanakumagawa begins its journey in the mountainous terrain of Aburayama, flowing through the vibrant districts of Sawara and Minami. It eventually merges with the Hakata River near Nishi Ward, completing its course. Originally, the Nanakumagawa was a much shorter river. As part of the city’s river improvement project, between 1971 and 1994, a significant portion of the Hakata River, about 3,315 meters, was modified. This modification essentially extended the Nanakumagawa, incorporating a section of the Hakata River into its flow. Further modifications took place between 2001 and 2009. These modifications addressed approximately 1,580 meters of the river. These projects aimed to improve flood control and enhance the river’s overall functionality within the city. The Nanakumagawa faced a significant challenge in 1999 and 2003. Heavy rainfall led to devastating floods in the river’s basin, causing widespread damage. These events highlighted the need for comprehensive flood control measures. In response, Fukuoka City embarked on a collaborative effort with Fukuoka University. This partnership focused on developing and implementing effective rainwater runoff control measures. One innovative solution involved the creation of an artificial grass ground at Fukuoka University. This ground, spanning approximately 10,000 square meters, acts as a large-scale infiltration system. It effectively absorbs rainwater, reducing the burden on the Nanakumagawa during heavy downpours. This system also helps to replenish groundwater resources and mitigate the urban heat island effect. The artificial grass ground incorporates recycled tire chips and a specially formulated soil mixture. This mixture creates a porous structure that allows for both water infiltration and retention. Notably, the artificial grass developed here at Fukuoka University has received international recognition. It has been tested by FIFA and awarded the highest rating for artificial turf. Ongoing research continues to assess the effectiveness of these rainwater management techniques. The knowledge gained from this collaboration aims to contribute to more sustainable and resilient urban water management practices.