Developing practical numerical flood simulations in urban areas
Numerical simulations of floods in urban areas are useful for establishing evacuation programs and revising future city planning. In the present study, a set of shallow water equations was used tosimulate the swift current on the streets to characterize horizontalflow diversion and concentration considering actual building configurations. The finite volume method was applied to an unstructuredtriangular mesh system to express the orientation and physical characteristics of each building based on a detailed city map. Recently, we conducted laboratory experiments and applications for actual events to develop more accurate and practical simulations of floods in urban areas.
ALB measurements of channel bathymetry for river management tasks
Recently, an airborne laser bathymetry (ALB) system using simultaneously pulsed lasers of two kinds (green and near infrared types) has attracted the attention of river and coastal engineers for use as an efficient cost-saving surveying tool. This technology is effective for high-resolution measurement of planar bathymetry including the underwater bed profile. For this study, we applied a developed ALB system and examined the accuracy in the targeted section by comparing the ALB data of 2 m horizontal resolution with existing survey data obtainedusing the conventionalmethod. Then we evaluated the effects of usinghigh-resolution ALB data in river flow analysis.