The Water Quality and isotopic composition on T, ²²²Rn, D and ¹⁸0 of ground water discharge in the adit for power station were investigated. Main obtained results are summarized as follows:
1) Investigation on the quality of ground water shows that the ground water is intermixed by comparable amount of surface water.
2 ) Investigation on the isotopic composition of ground water also shows the same result as inferred from water quality.
3) It is expectated that the characteristics of origin and intermixed surface water are cleared by detailed investigations on T, ²²²Km, D and ¹⁸0 isotopic composition of ground water discharge.