The definition of environmental geological maps are not yet fixed completely, but it is considered that the maps are produced for terrain evaluation, especially for urban planning, and are combination of maps derived from fundamental geological maps and maps of the other natural and man-made terrain conditions. The author pointed out that geological data-base for terrain evaluation needs to represent three dimensional recognition of each rock masses and their constitution, which emphasize physical geological characteristics responsive to natural and man-made impacts caused by urban developments. These physical geological characteristics were acquired from lithostratigraphic classification, because petrogenetical nomenclature involves its physical geological characteristics which are subjected by its genetical environments. Among the items of maps for terrain evaluation, hydrogeological maps and topographic maps are well defined as mapping techniques. Maps showing recent geodynamic processes are not yet completed for earth's total systems, although most informations of recent geodynamic processes are represented in geomorphologic conditions and their mutations. In Japanese islands, recently urbanized regions are generally began from old town situated between lowland and hilly area, and sprawled towards center of lowland and terrace area, which is composed of soft Quaternary sediments. At that places, lithofacies are recognised by only driller's geologic logs and samples obtained from bore-holes. So, establishments of maps illustrated three dimensional extension of lithostratigraphic units are urgent necessities for environmental geological studies, although maps of foundation engineering conditions are often published.
It is emphasized that knowledges and experiences in economic geology are absolutely necessary for solving some environmental problems caused by the development of mineral deposits. Soil and water pollutions by minor elements of heavy metals are usually observed in the neighborhood of metal mines. Considering the basic geochemical problems on the origin, dispersion and concentration of heavy metal elements, environmental pollutions accompanied by the development of mineral deposits are usually composed of natural and artificial pollutions. It is very difficult to divide both these pollutions, however, making the most of knowledges and experiences in economic geology, collecting the various useful data, having a good command of high techniques, such as simulation analysis, step by step progress must be made for solution of the problems. In addition, examples of environmental geological survey by soil and water and outlines of environmental survey with development of geothermal energy are shown, and, importance of framing background data and prosperity of underground injection of mine drainage are also mentioned.
There are some empirical roules to be observed in the tunnel route location. The author discusses mainly on the tunnel route selection concerned the problems of depletion of water resources from his engineering experiences from a standpoint of environmental geology.
This report studies the following problems. 1) To examine the effect of geology and topography as the controlling factors on groundwater flow systems. 2) To research the behavior of pollutants in the porous media concerning to groundwater flow systems. In the first subject the author discusses that how far the effect of geologic and topographic conditions extend on groundwater flow pattern. An example is summarized in Table 1. In the second subject he emphasizes that the sedimentary facies, many types of heterogeneous configurations and interlayered clayey deposits are important as the controlling factor on the behavior of pollutants. A few of his recent studies are introduced in this paper.
A computer program for the calculation of both the surface and the groundwater runoffs from a watershed in a mountainous area is newly coded. This program is mainly based on the Finite Element calculation of the three dimensional groundwater flow in a high permeable layer developing beneath the slope surface in a watershed. The amount of the surface flow come out at each saturated nodal point located on the surface can be evaluated by taking the difference between the rain volume given in the point and the calculated volume of rain which infiltrates into the layer from the point. As the runoff phenomena can be physically simulated by the use of this program, the hydrogeological condition in a watershed may be back-analytically estimated if the runoff data is given. The hydrogeologic condition in the Inuyama test field is successfully estimated from the analysis of the runoff data which corresponds to a short durated but intense rainfall. It is found that the permeable layer in this field should have the nature that the permeability under the unsaturated state rapidly increases if the moisture content in the layer exceeds a critical value.