The author is reporting of several findings, resulting from the author's experiment of structure and water permeability of shallow layer at zero order channel basin in the Tama Hill(Fig. 1).
From the results of tests at the broadrige except at the spur, it has been shown that the residual soil zone runs almost parallel to the land surface and makes almost the same thickness. On the downstream from the nick point, it has been proved that the valley-bottom is formed by transported soils(Fig. 5, Fig. 6).
At the residual soil zone, it was found that the permeability coefficients of the upper soil layer are larger than those of tije lower soil layer and the permeability coefficients of the upperstream are smaller than those of the downstream.
Moreover, at the thalweg in this drainage basin, the strongest correlation was observed between field permeabilities and altitude differences. The correlation coefficient at the upper soil layer is 0.937 and at the lower soil layer is 0.918 except for the remarkable difference of.*1 and(Fig. 7).