Recently, the demand for deep underground excavation and the development and utilization of its resources has increased. This raises a need to predict the behavoir of the groundwater in multilayered aquifers in order to promote its conservation. The exact determination of hydraulic properties of each aquifer is very important for the correct groundwater flow prediction. Pumping tests are usally per- formed under the multilayerd conditions. It is, however, difficult to analyze the data obtained from the pumping test under these conditions "analytically".
In this paper a new method of estimating aquifer coefficients from pumping test data in multi- layered aquifers is proposed. In this method a nonlinear least squares algorithm incorporating coupled stress-flow finite element analysis is used. The advantage of the proposed method is in the possibility of indentifying the optimal hydraulic properties both aquifers, and aquitards. Finally, for estimating of groundwater conservation, the behavior of this groundwater near the excavation site is predicted by a numerical method.

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The experimental field is located on the coast of the Japan Sea and in the north of Fukui prefecture. Some experiments with regard to the aquifer thermal-energy strage (ATES) have been carried out in the field for several years and the characteristics of these experiments were as follows;
(1) It was not the recharge through well, but the water spreading with some ditches that was adopted for the artificial recharge.
(2) Reservoir for heat and water was an unconfined aquifer and was located shallow depth below the surface.
(3) Recharge water used for these experiments was river water and it was naturally heated to an average temperature of 25t in summer.
The following are mainly identified by examining the heat balance of aquifer and by trying to compare the observed heat data with the approximate values that were lead from the simplified analytical models.
(1) The principal factor concerning the loss of heat in reservoir was the heat dispersion in aquifer caused by natural groundwater streams at this field.
(2) The heat conduction models are efficient for estimationg the change of heat capacity in the. aquifer after recharge.

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A new horizontal permeability test is proposed. The apparatus for the permeability test has been developed on the basis of the consolidation cell devised by Rowe and Barden. (1966). The size of the soil specimen is 20cm in diameter and 6.7cm thick. A rubber jack is placed over the spacer disc and is fed with water connected with the constant pressure supply line through a valve in the cell cover, applying to the soil specimen a uniform pressure up to approximately 5kgf/cm2. Vertical compression of the specimen is indicated by a hollow stainless steel spindle attached to the rubber jack and passing through the cell cover. The compression is measured by means of a dial gauge mounted on a bracket on the cover. Two slits are opened, diametrically opposite, on the side of the oedometer ring. Water under constant pressure is supplied through the side slits and fed into the soil specimen to establish steady seepage across it in the horizontal direction. The seepage thus obtained makes it possible to compute the coefficient of horizontal permeability at the end of each loading. The vertical permeability of a clay specimen cut to the initial size of 15cm in diameter and 4 cm in thickn'ess was measured also in a Rowe-type consolidometer capable of flowing water vertically through the specimen under a constant head. Direct measurement of the vertical permeability was made at the end of each loading of the consolidation test. Under relatively low consolidation pressures the seepage quantities both in the vertical and horizontal directions are approximately of the same maguitude, while with increase in the applied vertical pressure the flow in the vertical direction decreases more markedly than that in the horizontal direction. Therefore, it is considered that as consolidation proceeds the soil structure become more oriented in the horizontal direction, causing water to flow more readily in the horizontal direction and resulting in more distinct anisotropic permeability. Comparison was made between the values of the coefficient of permeability determined from the proposed permeability tests and from the oedometer tests. The values from the former were significantly greater than those from the latter. It is also noted that the coefficient of permeability increases as the size of specimens increases.

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A new horizontal permeability test is proposed. The apparatus for the permeability test has been developed on the basis of the consolidation cell devised by Rowe and Barden. (1966).
The size of the soil specimen is 20cm in diameter and 6.7cm thick. A rubber jack is placed over the spacer disc and is fed with water connected with the constant pressure supply line through a valve in the cell cover, applying to the soil specimen a uniform pressure up to approximately 5kgf/cm2. Vertical compression of the specimen is indicated by a hollow stainless steel spindle attached to the rubber jack and passing through the cell cover. The compression is measured by means of a dial gauge mounted on a bracket on the cover.
Two slits are opened, diametrically opposite, on the side of the oedometer ring. Water under constant pressure is supplied through the side slits and fed into the soil specimen to establish steady seepage across it in the horizontal direction. The seepage thus obtained makes it possible to compute the coefficient of horizontal permeability at the end of each loading.
The vertical permeability of a clay specimen cut to the initial size of 15cm in diameter and 4 cm in thickn'ess was measured also in a Rowe-type consolidometer capable of flowing water vertically through the specimen under a constant head. Direct measurement of the vertical permeability was made at the end of each loading of the consolidation test.
Under relatively low consolidation pressures the seepage quantities both in the vertical and horizontal directions are approximately of the same maguitude, while with increase in the applied vertical pressure the flow in the vertical direction decreases more markedly than that in the horizontal direction. Therefore, it is considered that as consolidation proceeds the soil structure become more oriented in the horizontal direction, causing water to flow more readily in the horizontal direction and resulting in more distinct anisotropic permeability. Comparison was made between the values of the coefficient of permeability determined from the proposed permeability tests and from the oedometer tests. The values from the former were significantly greater than those from the latter. It is also noted that the coefficient of permeability increases as the size of specimens increases.

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