Author(s): Mikio Sasaki; Hitoshi Tanaka; Makoto Umeda
Keywords: River mouth; Saltwater; Estuary; Salt wedge; Boundary layer; Mixture of seawater
Abstract: First in the present study, the field observation was carried out to investigate the movement of the seawater in the Lake Jusan. The boundary layer, the shape of the saltwater edge and the mixing of freshwater into seawater are shown clearly. The vertical and horizontal distributions of the salinity are also shown clearly. Second in the present study, the inflow rate of the seawater up to the lake was calculated for five years from 2003 to 2007. The amount of fresh water in Iwaki River in April in 2007, May and June in 2003 was less than that in ordinary year because the water of snowmelt was few due to the few snowfall. Consequently, the water level of Lake Jusan did not go up because the inflow of the freshwater from Iwaki River into the lake was few due to the few of the snowmelt water. The inflow rate of the saltwater up to the lake is influenced by the amount of snowfall and precipitation. When the snowfall and the rain are few, the generation of the backflow decreases.