Abstract
The basin of the East Takase River and the right-hand shore of the lower Uji River had recquired continual cares owing to the natural changes of the water course and to the human utilization of their tracts. At the lower Uji River, the junction of the three affluents has gradually moved towards downstream at the hitherto repeatedly occurred joint changes and undercutting of the embankment; so now the area around the Yodo station, where was the pivot point of the joint changes, shows a remarkably intricate geographical feauture.
To avoid the flood damage, houses of the community, almost without exception, were constructed in the past time with the raised foundations on the natural embankment. However, since 1945 the surface form of this district is changing into a tract of housing place. At the formation of residential area considerations were paid only to the accessibility of traffic convenience, not to the danger of flood damage. Before everywhere at Takeda, west of the Takase River, and on the right side of the Lower Uji River, there are many risks of flood disaster. Still building of houses in this lowland is going on ever now.
The residential lots on the higher lands had exceedingly increased the rate of run-off, and it incessantly forced the plans of prevention works against flood drastically to be changed. Such plans for the East Takase River are partially succeeded in this aim, and if completed, the damages by storm rains will be warded off. In case of rainfall exceeding 20mm per hour, the area of lowland will be flooded.
The draining plans of stagnant waters in Southern Kyoto, based not on the short term rainfalls, but on a such one of 269.7mm per 3 days, or where the houses are crowded such as in the basin of the East Takase River, will have to be improved to a considerable degree.
In fact, such plans should be schemed with a far-reaching viewpoint of the expected formation of residential lots in the near future. Without such insight flood disaster of this district will not be decreased.
