This paper is principally concerned with the geochemical problem of dissolved minerals transported by the Asahi-gawa River in Yamagata Prefecture. Survey was conducted during the period 1959 to 1960.
Regarding the quality of water, the concentration of anion is in the order: HCO3->Cl->SO42- for several samples taken from the drainage system. In the rivers contaminated by mineral deposit in the drainage basin, the relationship: SO42->HCO3->Cl- or HCO3->SO42->Cl- is found to exist.
In Figs. 4-7 are presented the results of the measurement on the transportation of some ions in solution. From the statistical treatment of these data, the following equations are obtained :
Ca2+ : Qd=11.6Q0.61
Cl-:Qd=15.4 Q6.62
SO42-:Qd=7.8Q0.85
Si02:Qd=9.1 Q1.05
wher Qd is dissolved mineral discharge in g/sec, Q flow rate in m3/sec. For COD, the equation : Qd=aQn is established by the same procedure where a is 0.21 and n 1.45. Moreover, the relation between evaporation residue and flow rate was studied. The results are expressed as follows :
Q>6m3/sec : Ré=25 Q0.36
Q<6m3/sec : Ré=105-13.8Q
in which Ré is evaporation residue in mg/1.
