Integrated flood models have been previously developed to simulate diverse inundation situations and combined with models of storm surges and river floods. However, drainage systems, ground elevation, and surface information of human settlements have only been digitized in large cities. Digitization of surface information is essential for developing a drainage system model for pluvial flood analysis. Occasionally, suburban drainage areas exhibit various complex land-use conditions, including residential and green areas, agricultural land with drainage, and irrigation channels. Herein, UAV photogrammetry was applied to obtain high-resolution geospatial data associated with small-scale flood-prone areas whose elevation, land-use, and waterway networks have not been elucidated sufficiently. The resolution of elevation and land-use data ranged from 2.61–5.22 cm/mesh. The measurement accuracy of the width and depth of the open channels was high, and the errors were mostly within 10%. A drainage system model was developed using data on open channel, elevation, and land-use.

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