This paper is concerned with a floating island as ecological flood alleviation. Contrary to the flood alleviation scheme proposed by Ministry of Construction, Japan in 1971, Komatsu-Tenmangu-shrine was preserved in the oval-shaped bank by the persevering resistance by citizens, scholars, head and staffs of the shrine, and many others, and the riparian work was finally completed on 19 November 2017. The final countermeasure has succeeded to harmonize the flood alleviation of Kakehashi-basin with the preservation of Komatsu-Tenmangu-shrine. The riparian work has been welcomed by the majority of citizens in Komatsu-city as well as people concerned with such as staffs in the Ministry of Construction, Ishikawa prefecture, and Komatsu-city. On the basis of Inyogogyo principle, it is realized that Komatsu-Tenmangu-shrine lies at an immovable point in the straight line connecting Komatsu-castle and Kanazawa-castle. In the final countermeasure, the primary vision due to Ministry of Construction, which is the satisfactory riparian work for the flood alleviation scheme (100-year design flood) has been integrated into the existing carriers, viz. historical Komatsu-Tenmangu-shrine, fauna and flora, and immovable shrine position based on Inyogogyo principle. It is suggested that in the original planning and design of the Komatsu-Tenmangu-shrine in seventeenth century there had been a tiny germination of the modern concept of sustainable development.

本文将浮岛作为生态防洪措施。与日本建设部于1971年提出的防洪计划相反，由于公民，学者，神社首长和工作人员以及其他许多人的顽强抵抗，小松天满宫被保存在椭圆形的河岸中。沿河工程终于在2017年11月19日完成。最终的对策已成功地协调了Kakehashi盆地的防洪与小松Tenmangu神社的保护。河岸工程受到了小松市大多数市民以及建设部，石川县和小松市的相关人员的欢迎。在Inyogogyo的基础上从原理上讲，小松天满宫位于连接小松城堡和金泽城堡的直线的不动点上。在最后的对策中，建设部的首要构想是将其用于防洪计划（100年设计洪水）的令人满意的河岸工作，即已纳入现有的承运人。基于Inyogogyo原理的历史悠久的小松-Tenmangu神社，动植物以及不可移动的神社位置。建议在十七世纪的小松天满宫最初的规划和设计中，对现代可持续发展概念的萌芽很小。