宇美川

Slipping through the valleys of the Mikasa mountains, the Umi River begins its journey. It flows towards Fukuoka City, where it eventually merges with the Naka River. The Umi River is more than just a waterway. It’s a vital part of Fukuoka’s history and ecosystem. In 2005, heavy rains caused devastating floods along the Umi River. This disaster highlighted the need for improved flood control measures. The river’s inadequate channel capacity and the presence of obstacles like fixed weirs and bridges exacerbated the damage. The flooding also revealed another problem. Debris, including driftwood and earth, flowed downstream, blocking the river’s flow. This blockage worsened the flooding, emphasizing the interconnectedness of the river system and the need for a comprehensive approach to flood control. After the 2005 flood, the Umi River underwent significant restoration and improvement work. The project aimed to prevent similar disasters in the future. Engineers rebuilt weirs with new structures. They carefully considered the river’s water intake, irrigation schedule, and irrigation area. Residents shared their experiences, recalling how driftwood and rocks flowed down from upstream during past floods. They hoped for stronger weirs to withstand such events. The new weirs are a combination of steel and rubber, designed for durability and efficient water management. These structures offer a balance between cost-effectiveness and resilience against rocks and driftwood. They also require less maintenance compared to traditional steel weirs. This new approach to weir construction represents a significant step forward in protecting the Umi River and the communities that depend on it. The Umi River restoration involved more than just infrastructure improvements. It included careful consideration of the environment. The confluence of the Umi and Naka rivers is a habitat for rare bottom-dwelling animals and birds. To minimize disruption to these ecosystems, the excavation work was carried out with utmost care. The project also addressed the risk of soil erosion and landslides. Protective dams were built using a combination of concrete and steel-framed structures to stabilize the riverbanks and prevent future disasters. Today, the Umi River flows more freely, its banks reinforced. The restoration project serves as a testament to Fukuoka’s commitment to both its citizens’ safety and its natural environment.