Groundwater flow analyses in Japan; part 3 : A Case study in Hokkaido

not registered; not registered  ; Koide, Kaoru; Yanagizawa, Koichi

An extensive study program has been carried out by PNC to estimate hydrogeological characteristics of deep underground in Japan. As a part of this program, groundwater flow analyses in Hokkaido were conducted. For the analyses of Hokkaido area (500 km 400 km 10 km deep), a hydrogeological model representing topography, distribution of hydraulic conductivity was developed on the strength of information available from open literature. By the use of this model, steady state three-dimensional groundwater flow under a saturated-unsaturated condition was calculated by means of finite element method. The results are as follows : (1)Distribution of piezometric head corresponds with topography in the study area. (2)Piezometric head distribution is hydrostatic below E.L.-1000 m in the study area. (3)Hydraulic gradient in the study area is less than 0.04 below E.L. -500 m. (4)Difference of boundary conditions at the shore side this model does not affect the result of the analyses.