ANALYSIS OF FLOODING PROCESSES IN KUSAKA AND HAGE BASINS CAUSED BY HEAVY RAINFALL ACCOMPANIED WITH 7505 TYPHOON, AUGUST, 1975

The Kusaka and the Hage basins located in Shikoku District, west Japan, suffered severedisasters from flood caused by record heavy rainfall of 676 mm and 552 mm in areal depths, respectively, in August 16～17, 1975, accompanied with 7505 typhoon.This paper discusses the flooding processes and factors relating to the disasters to suggestsome means to prevent such the disasters. The flooding processes are analyzed to simulatethe highest flood traces in several places along rives in the basins by the method of trial and errorof computation based on the mathematical models of kinematic wave for non-inundated water-sheds and dynamic wave for inundated areas. Hydrographs of flood water level are also esti-mated under some hypothetical drainage facilities to give a suggestion of policy for preventingor mitigating disasters from flood.