Some remarks on the transportation of dissolved minerals of the Su-kawa River, Yamagata City

Abstract

The Su-kawa River, which starts from the Zao volcanic region, has ever been famous for poisonous acid water. The author has continued the investigations on this river with the aim at elucidating the hydrological features. The results of these have been often published by him for these ten years. In this paper, some remarks are presented on the transportation of dissolved minerals of this river.
Regarding sulfate and chloride ions, each mineral discharge is the function of flow rate. The functional form is expressed as follows : Qd (SO₄^2-) =928Q^0.665
Qd (Cl^-)=183Q^0.680
where Qd is mineral discharge and Q flow rate.
Moreover, the total discharge of sulfate ion is estimated to be 23, 000 tons per year. Such a large amount of the ion is transported to the river with thermal water gushing from the Zao spa.
Similarly, the total discharge of chloride ion is determined to be 4, 500 tons per year.
The annual observation of the acidity reveals that the Su-kawa River transports about 20, 000 tons of free sulfuric acid in a year.