Abstract
In the frequently inundated Nishikanbara Area, the Jogo District, located in the upper reaches, had conflicts with, the Gego District, located in the lower reaches, over its irrigation and drainage.
Gego, suffering from poor drainage, organized the Shinkawa Sosui Regular Water-Use Cooperative in advance of the Jogo District, and improved its drainage by bearing a part of the cost of prefectural work. But this aggravated their conflict.
Then the Jogo District, suffering from a shortage of irrigation water, organized the Jogo Flood Prevention Cooperative on the condition that it bear all the cost of works in the Gego District and that works in Gego preceded those of Jogo, and succeeded in big prefectural works to improve drainage of the Gego District and irrigation of the Jogo District. These works adjustted their conflict, but they extended over long years and imposed a heavy burden on Jogo.
Thus Jogo completed a new irrigation system at a great cost. Jogo compensated the area on the left bank in the lower reaches for its water loss, when it took much more irrigation water at the upper intakes. But it was able to take water without any trouble and without any compensation for Gego located on the right bank in the lower reaches.
Therefore Jogo, behind Gego in implementation of works to improve irrigation and drainage, succeeded in obtaining a sufficient supply of irrigation water. On the other hand, former works to improve drainage in the Gego District became less effective on account of the increase in drainage water from Jogo as the works of Jogo progressed. Accordingly, at some parts of Gego new works for drainage were carried out.
Consequently, adjustment of conflict concerning irrigation and drainage between the two areas in the upper reaches and lower reaches requires organization of water cooperatives that gains a consensus of the area and bears allotment of works. Then the adjustment is arranged by intervention of the nation or the prefecture with large funds. Also in paddy field farming areas it is important that works to improve drainage are implemented with consideration for new supplies of irrigation water.
