1990 Volume 42 Issue 6 Pages 11-17
In order to operate the debris flow alert system, the critical rainfall value is needed. Therefore a shortterm rainfall forecast method is developed in author's formar study (1990) .
Here in this paper, two remining problems in it, i.e. 1) the determination of the normal rain conversion coefficient between base station and any un-obserbed pint in the basin, 2) analysis of the relation among effective rainfall amount, rainfall intensity and occurrence probability of debris flow are studied.
The normal conversion coefficient at any point is expressed by an equation made up of topogrophic factors and corrective term. These factors in 1km grid square is given respectively to simulate the aim rain.
The occurrence probability of debris flow or other sediment disaster is shown by diagram consists of effective rainfall factor and 1 hr peak rainfall factor. some sample critical lines are determined on it. Consequently the operation of debris flow predicting system can be carried out using the results obtained through this series of studies.