On the change of rivers and national land in Japan and river environmental problem predicted to be occurring in Monsoon Asian Countries and Countermeasures on them

Abstract

It is investigated about the changes of population and national land use in Japan in the past about 2000 years. And it is shown the population change in the last 100 years and for the next 100 years. And it is clarified that 1) In the last 2000 years, Japan has the three times of rapidly population increasing and large-scale development of floodplain. 2) the Japanese population changes in the last 100 years can be called “population explosion”, and the predicted population changes in the Monsoon Asian countries for the next 100 years will have same tendency of this “population explosion” in Japan, and 3) from these result, it could be expected that Asian Countries will meet the similar problems for river environment which Japan has experienced in the future.To cope up with these problems. the network for river environment focusing on Asia should be established.