抄録
To separate non-polluted ground water run-off origined by precipitation from observed river discharge at urban areas, electric conductivity of water was measured at wells, springs and gauging stations of rivers.
Electric conductivily of water is closely related to concentration of chloride and different basins have each regression lines.
From these lines electric conductivitiy of non-polluted ground water (Cg) was estinated and non-polluted ground water run-off (Qg) was evaluated by observed discharge and electric conduct ivity of water at each rivers.
