In the field of groundwater flow analysis, analysis model validation is important from the viewpoint of assuring the quality of analytical results. Groundwater level and pressure data obtained from observation wells, therefore, are widely used for the refinement and validation of analysis models. This study points out, however, that without appropriate interpretation of observation data, analysis models can be misevaluated in the validation process.
For the purpose of model validation by use of groundwater observation results, this study also shows examples of erroneous analysis model validation anticipated under the current conditions. Furthermore, this study presents a method using an analysis model incorporating observation wells and as a result of examining the method which took the observation well into the analysis model, the applicability and usefulness became clear.
By combining the creation of an appropriate groundwater observation system using observation wells with the incorporation of the observation system into the analysis model, a groundwater flow analysis model using water level and water pressure data can be validated.

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This study evaluated the results of numerical simulations of the migration of chemical compounds in soil gas to develop a method for estimating the location and depth of a soil pollution source. It was found in this study that the relation between the variance or the average concentration of a chemical component and elapsed time approximated to a quadratic function and the quadratic equation could then be used to estimate the pollution source location with 2-4m errors. Moreover, because the first-degree term in the quadratic equation tended to increase with soil depth, it could be used to estimate the depth of the pollution source.

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Kumamoto area is very famous for its rich volcanic groundwater resources for their city water supply and much management efforts have been done for their sustainable use. The success of artificial groundwater recharge through abandoned rice paddies induces the revision of prefectural groundwater ordinance for the better management of local groundwater for their future generations. This ordinance includes the pumping permission coupled with the artificial recharge countermeasures and this is the first trial pumping regulation in the no groundwater disaster area of Japan.

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