Author(s): Kenji Kawaike; Hirotatsu Maruyama; Masato Noguchi
Linked Author(s): Kenji Kawaike
Keywords: Inundation flow analysis; Low-lying area; Countermeasures against flood disasters
Abstract: In this study, a comprehensive numerical model, which can simulate inundation flow caused by heavy rainfall in a low-lying area, is developed and applied to the Isahaya area, Nagasaki Prefecture, Japan. This model comprises the Hommyo River channel, the Isahaya low-lying area and hillside area with steep slopes, and each part adopts (1) one-dimensional unsteady flow model using characteristics method, (2) two-dimensional inundation flow model using unstructured meshes and (3) runoff model using kinematic wave method integrating surface and sub-surface flow, respectively. The validity of this model is discussed by comparing the simulation results with the actual records of inundated area and water level of the river network observed at the disaster of 1999. The inundated area around the center part of the studied area can be well expressed by this simulation. But because of inappropriate spatial distribution of precipitation, there are some disagreements between the simulation results and actual records in the other parts of the studied area. Then, as the application example of this model to countermeasures against flood disasters, the effect of additional pump capacity is discussed. From the simulation results, the relationship between additional pump capacity and inundated area, and between additional pump capacity and water level of the Hommyo River channel, can be obtained.
Year: 2005