Abstract
It is difficult to measure the salt-water intrusion in the field though the environment of the Lake Ogawara consists on a delicate balance of the salt-water intrusion and the salinity circulation. In this study, the amount of the salinity outflow-inflow is estimate respectively by a multiple linear regression analysis and fuzzy reasoning by using only the water level of the river mouth and the Lake Ogawara. The tendency of the amount of the salinity outflow-inflow in winter was able to estimate by the both of a multiple linear regression analysis and fuzzy reasoning.
