A STUDY OF FLOOD INUNDATION PROBABILITY IN TIME AND SPACE

In order to establish the optimal flood control system with the comprehensive criteria on the whole river basin, it is necessary to examine the effects of flood control projects in the system consisting of multi-subbasins and multi-defence points on the flood inundation probability in time and space. In this paper, firstly, the flood probabilities in time and space among the subbasins are assumed through the stochastic structures of hourly rainfall and the runoff system model. Secondly, their probabilities are transformed into the flood inundation probabilities at multi-defence points in the river basin based on the flood routing model including the effect of dam control and overflow at the point being lack of river capacity, and the shift operation on non-homogeneous finite state Markov chain. Those estimated flood inundation probabilities will be introduced into the decision model of flood control system.