In this study, applicability of one-dimensional infiltration model for behavior of four Non-aqueous phase liquids (NAPLs) in unsaturated/saturated porous media was investigated by comparing of calculated values with observed values. The progressing rate of NAPL front in glass beads layers, vertical distribution of NAPL and water after NAPL movement stopped, and total amount of volatilization of NAPL during experimental period were used as observed values. It is found that this model can present behavior of NAPLs, whose densities are larger than water and spread coefficients are positive, but that the model tended to overestimate downward migration of LNAPL such as Toluene. Moreover, this model cannot be applied to NAPL such as Bromoform, whose spread coefficient is negative.

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A new hydraulic conductivity test apparatus is proposed which was developed to quickly and accurately obtain detailed measurements of saturated permeability data. It is possible to install both the constant head method and falling head method, and the system is changed as needed. This apparatus can be used for easily measuring the pore pressure parameter B-value for the degree of saturation. The size of the soil specimen is 5. Ocm in diameter and 5.1cm thick. There are five soil specimens in the chamber, to which a uniform pressure of up to 50kPa is applied by the falling head method. A comparison was made between the permeability-related values of the change according to the situation, such as suction time, pore pressure parameter B-value, hydraulic gradient and Reynolds number obtained by the proposed test apparatus. From the result, it is concluded that this apparatus can accurately determine the saturated permeability coefficient and is useful for quickly obtaining detailed data.

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The authors conducted the study to clarify the role of aquitard on nitrate in groundwater in Tsukuba upland and the slope. The groundwater flow pattern was primarily horizontal in the sand and gravel layer and vertical (downward) through the underlying aquitard with dark greenish gray color. Groundwater in the sand and gravel layer contained nitrate of 0.350-1.150mM and in the aquitard with dark greenish gray color did below 0.015mM. The groundwater flow pattern and the simple chemical mass balance showed that biochemical barrier such as denitrification led to the decrease of NO₃^- concentration in the silt and clay layer with dark greenish gray color of the slope. On the other hand, in the upland, the results of the measurement of electrical conductivity in groundwater and the observation of water level indicated that the clay layer with dark greenish gray color filled the role of hydraulic barrier.

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