On the Topographic History developed along the Basin of the Shimanto River, Kochi Prefecture and its Significance in Engineering Geology

The present meander of the Shimanto River is naturally considered to have been related intimately to the topographic history developed along its basin and to be a part of remains of the free meander formed previously on the peneplain through topographically old stage. Owing to circumstance in that with upheaval or upward warping, resulted from subsequent movement, of the block concerned the peneplain might have been eroded down from the lower to the upper part of the river and thereby gradually reduced, its vestige is now observed remaining merely in the confined terrain while most parts subjected to severer agency seem to have already been disappeared at all. On the other hand, inasmuch as the effects of weathering are conspicuously ascertainable within considerably deeper layer of the b3sement rocks probably exposed on peneplain for long duration at certain old stage, their important roles in topographic variation as well as in practice of engineering works are also accountably to be noticed. In the light of this regard, some views are here proposed on the subject specifically concerning the connection of weathering process appeared on the basement rock with practice of the electric generation by means of water power.