Nagai City, Yamagata Prefecture: Natural Regeneration of the Mogami River Basin (1990s-2000s)

Nagai City, Yamagata Prefecture: Natural Regeneration of the Mogami River Basin (1990s-2000s)
Nagai City in Yamagata Prefecture is known as a city of water, where the Okitami-no-gawa and Okitami-shirakawa Rivers flowing from the mountains of Iide and Asahi meet the Mogami River. However, since the period of rapid economic growth, the river has been concretized and the channel has been straightened, resulting in the loss of its once diverse rapids, pools, reed beds, and riparian forests.
In 1997, the River Law was revised to add the development and preservation of the river environment as a legal objective, and this encouraged the institutionalization of river development with the participation not only of the government but also of local residents. In the Mogami River basin, the introduction of nature restoration and multinatural construction methods began, and Nagai City also adopted a policy of emphasizing environmental conservation when excavating river channels and constructing revetments.
Under these circumstances, Nagai City's river restoration project was unique in its emphasis on citizen participation. Efforts were made to restore a variety of streams, mainly along the Okishino River, a tributary of the Mogami River, by restoring riparian vegetation, constructing fishways, and creating a biotope-like environment along the water's edge. Citizens' groups continued to conduct cleanups, water quality surveys, and observation meetings, and actions to protect the river environment took root as daily activities of residents who were not experts in the field.
In the 2000s, the Mogami Riverfront Area was developed as a walking path and waterfront area through the "Kawamachi-Development System," and a boat landing was restored, a cherry blossom grove was created, and a circulation route connecting the town and the riverfront was developed. These improvements have provided an opportunity for citizens and tourists to engage with the river on a daily basis, and Nagai City has attracted nationwide attention as an effort to revitalize water culture in the modern age. Another unique feature of the project is that it was carried out through a series of dialogues on the maintenance and utilization of the river, with the cooperation of the government, NPOs, chamber of commerce and industry, and others.
The river is also being used as a place for education, and schools are conducting water quality surveys and biological observation as part of their comprehensive learning programs. The view of the Mogami River from the footpath is linked to the history of the river's prosperous boat traffic and the surrounding irrigation canal culture, and the connection between local life and the river has been rediscovered. Through these activities, the citizens of Nagai City have shared the awareness that protecting the river means protecting the foundation of the local culture and lifestyle, and Nagai City's efforts have been recognized as a practice ahead of its time in watershed flood control and nature restoration.