小川原湖北東部浅水域における塩水侵入へ塩水侵入規模と風場が及ぼす影響の検討

Abstract

A wide shallow is in the northeastern area of Lake Ogawara. A part of the saline intruding from Takase River into the lake can spread to the shallow area and be stored in the area. To evaluate a saline-storage capacity of the shallow area quantitatively, three-dimensional numerical current simulations were conducted. A series of the simulations of the saline intrusion was conducted with various intrusion-volumes and wind conditions. The simulation results show that the saline intrusion in the shallow area can be affected by the wind speed and the storage capacity can be drastically enlarged under a strong eastern wind. An empirical equation to evaluate the storage capacity is proposed as a function of the eastern wind speed. Using the equation, the average storage capacity is estimated with all saline intrusion events in the recent decade and the capacity is near the value suggested by the previous field surveys.