横大路低平地域の内水の現状と将来予測

Abstract

In this paper, runoff characters in the present and their changes presumed in accordance withurbanization in the near future in Yoko-oji low-lying drainage basin are discussed on the basis ofobserved hydrological data in June and July, 1969. The outline of this study is as follows:Hydrographs of runoff discharge at the end of the main drainage channel are estimated usingrecords of water levels in the channel and rivers enclosing the basin, pump operation and so on.But there exist few questionable problems in accuracy of the hydrographs because of the unfitnessof water gauge locations and inflow from the rivers through embankments and foundations. Thekinematic wave method is applied to synthesize hydrographs using a simple model of the basin.The results are fairly good in comparison with synthesized and estimated hydrographs.A model of the basin is made under some assumptions, and the values of equivalent roughnessare selected to meet with surface conditions, in the future. By using this model, runoff hydrographsarc synthesized for given rainfalls. As the results, it is presumed that the peak discharge of floodrunoff in the furture must be two and/or five times as large as the ones in the present.