Abstract
The starting point of the pollution of our country is an Ashio mineral pollution event of the 19th century. Shozo Tanaka described flood control theory about the necessity of the protection of natural environment through practice by this event. The purpose of the present study is to consider how to succeed to from Tanaka's flood control theory to a modern citizen volunteer concretely. As a result,Shozo Tanakas flood control theory has four sides of Traditional river technology by character of geographical features and water, Erosion control as the head of a river training, Flood control the mountain and river on earth, and Ideal way of the man activity that enjoys the life of the natural gift. At the present period, Watarasegawakenkyukai, which was succeeded to through elaborate study of Shozo Tanakas thoughts, was the center of the group that developed with the activity as a recovery of natural environment. Tanaka described the ideal way of the flood control and the man activity along working of natural environment. On the other hand, it was considered that a present civic group aimed at the recovery for past natural environment, and was adapting oneself to present natural environment.
