A new method to estimate specific storage and vertical hydraulic conductivity from pore pressure responses to atmospheric loading obtained at multiple depth intervals was developed. This makes it possible to estimate these physical properties even in the case where an unsaturated zone overlies the target formation, which have been difficult or impossible until now We developed a device to monitor pore pressures at multiple depth intervals in a single borehole. Atmospheric responses obtained by the developed device were successfully applied to the proposed method, and it was found that our method was applicable to obtain physical properties of the formation within practically allowable errors.

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Prediction of groundwater contamination spreading is important for effective groundwater remediation. In this paper, the groundwater contamination mechanism was estimated by using multivariate analysis. A two-dimensional numerical simulation based on the multivariate analysis was performed for prediction. This is simpler, and less time consuming than a three-dimensional numerical simulation. This simulation code is based on the mass transfer equation incorporating the adsorption-desorption potential caused by the difference between equivalent adsorption quantity and actual adsorption quantity. The numerical simulation results agreed very well with adsorptiondesorption experimental results, which suggests that the simulation code is suitable for practical application.
Our numerical simulation is targeted for the prediction of groundwater contamination of Higashine City, Yamagata. In this city, groundwater contamination by trichloroethylene (TCE) was confirmed in a 3km²area in 1992.
A water quality investigation was conducted at 51 wells in 1993. The main contaminated wells were classified according to cluster analysis, or multivariate analysis. Monitoring of TCE concentration is being continued on some of the main contaminated wells. Long term well monitoring shows that there are two hydrological systems, one in which TCE concentration is decreasing, while the other remains unchanged. Under the concept that the depth of these well's screens exist on the same two-dimensional domain, we have done two-dimensional simulations of the two hydrological systems. The simulation results correspond well with our monitoring results. The predictive capability of our combined cluster analysis and two-dimensional numerical simulation was confirmed and the simulation results show that the environment of this area is recovering.

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A new X-ray transmission measurement with dispersion X-ray spectrometry was developed to quantify three-phase fluid distribution in a porous medium. The X-ray transmission intensities through a porous medium were measured with energy dispersion X-ray spectrometry, and the spatial distribution of each phase (water, oil, and air) fluid in the medium was quantified by using intensities at two appropriate frequency bands. The technique was applied to measure the spatially distributed three-phase fluid contents in two different porous media, and was proved to be able to quantify three-phase fluid distribution in porous media with sufficient accuracy. This paper suggested the possibility to quantify temporal change of three-dimensional distribution of threephase fluids in a porous medium by integrating the energy dispersion X-ray spectrometry with traditional CT technique.

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In order to count the spatially heterogeneous environment itself as one of components of the engineering system, the following procedures must be considered: In order to count the spatially heterogeneous environment itself as one of components of the engineering system, the following procedures must be considered recognition of the importance to the engineering system of evaluations of the geological environment with spatially heterogeneous characteristics; In order to count the spatially heterogeneous environment itself as one of components of the engineering system, the following procedures must be considered designing a strategy for the investigation in the light of the above; and In order to count the spatially heterogeneous environment itself as one of components of the engineering system, the following procedures must be considered development of an uncertainty analysis methodology as a quality control on the evaluation method of the spatially heterogeneous environment.
Focusing on a firm scientific and technological basis for the research and development of the high-level radioactive waste geological disposal, a study of these procedures is reported in this paper. Consequently an“uncertainty analysis methodology associated with the characterization of the geological environment”was developed for the spatially heterogeneous characteristics of a geological environment. The developed uncertainty analysis methodology adopts a new approach, where all the possible options in models and data-sets that cannot be excluded in the light of evidence available, are identified. This approach enables uncertainties associated with the understanding at a given stage of the site characterization to be made explicit, based on the classification of uncertainties into variability and ignorance. The uncertainties could be reduced by screening to exclude models and data-sets that can be denied in the light of additional evidences obtained in subsequent stages.

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