Naturally produced tritium provides the hydrological information with a valuable tool for tracing groundwater through the hydrologic cycle. These investgatigations have been carried out using both naturally produced and atomic bomb-produced tritium.
This analysis was done by using liquid scintillation counter, preceded by electrolytic enrichment.
In the shallow groundwater, tritium concentration vary from 5∼6 TR to a few hundreds, while in Case of deep groundwater, the value is slightly lower. This is due to older existence of deep groundwater, it will cause various groundwater disasters.
The above became clear as a result of investigations on tritium concentration used to forecast groundwater disaster.

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The hydrogeological survey was carried out in Shinjo Basin in 1975 and the following results are obtained.
1) The upper Neogene formations and Quarternary strata are developed in Shinjo Basin.
2) The deluvium and alluvium are covered with the fan deposits which are 30 to 90 meters in thickness.
3) The groundwater aquifers in this basin are divided into the I, II, III and IV horizon beds according to the electric ground resistivity method.
4) The hydraulic conductivity is in the order of 10^-3cm/sec as in Yonezawa Basin but at the surface layer (to 30 meters in depth) it is 10^-1∼10^-2cm/sec.
5) The specific capacity of Shinjo Basin is relatively small compared with that of Yamagata or Yonezawa Basin.
6) The ground water is reserved in the uppermost Miocene (Sakegawa Formation). It must be noticed that the unreasonable pumping up from the uppermost Miocene Formation will cause the land subsidence.

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Stochastic approaches in groundwater hydrology have been rather limited towards evaluating the properties of flow in the porous media such as diffusion process. More recently the large scale problems of groundwater systems have been evaluated by stochastic approaches. In this paper, stochastic approaches in groundwater hydrology have been reviewed in focusing the researches by Freeze(1975). The definitions of important terms, homogeneous, uniform, and isotropic, have been discussed in connection with stochastic representations of porous media or aquifers.

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