In Ryuo where Midai-gawa River and Kamanashi-gawa River joined together (Formerly, Ryuo-cho, Nakakoma-gun, present day Kai City), banks called Shingen tsutsumi (banks of the river) were established to divert the course of the river for cultivation while the castle town in Kofu, was developed, which was an excellent example of flood prevention projects.
代表的事例として、甲府城下町の整備と平行して行われた御勅使川と釜無川の合流地点である竜王（旧中巨摩郡竜王町、現甲斐市）では信玄堤と呼ばれる堤防を築き上げ、河川の流れを変え開墾した。