松本川河口における塩水楔

概要

論文の詳細を見る
Most of the rivers, which empty into the Sea of Japan with a very small tidal range, are of the weakly mixing type, where fresh and salt waters are little mixed and respectively form separate layers. On the results of the field observation made on the mouth of the Matsumoto River being one of above rivers this paper represents. Then the characteristics of saline wedge are explaned due to the measured data of the river discharge, the tide, the longitudinal and vertical distributions of salinity and velocity and so on. Further, a mathmatical model of saline wedge on the river with various flow area has been considered and, assuming gradually varied flow, the simultanious ordinary differential equations for surface level and interfacial level have been obtained. This system is solved numerically by the modified Euler-Gauss's method, the characteristics of flow area being used at the boundaries of the domain. This method have been used for the calculation of the saline wedge in the Matsumoto River. Comparisons of the computation results with the measured have been made. Consequently it was made out that this proposed method was fairly useful.