FLOOD SIMULATION IN KLONGTOEY-WATTHANA POLDER USING MIKE FLOOD URBAN MODEL

Abstract

This study aimed to investigate the capacity of a drainage system in accommodating heavy rainfall in the Bangkok area. The MIKE FLOOD URBAN model, developed by DHI, was used in the study. The model consists of the rainfall-runoff model, 1-dimensional pipe-network model and 2-dimensional overland flow model. The KhlongToey-Watthana polder was selected as the studied area. Model calibration was done using rainfall data at every 15-minute interval from the 8th through 16th of October 2013, with a maximum
rainfall intensity of 32 mm per hour. Subsequently, model verification was performed using rainfall data at every 15-minute interval from the 17th through 24th of October 2013 with a maximum rainfall intensity of 76 mm per hour. Then the 1-dimensional and 2-dimensional models were combined to simulate 2-dimensional flood inundation via the use of a Digital Elevation Model (DEM) as an input to generate a flood map. The flood map indicated that many areas were flooded, with a maximum flood depth of 0.45 m.
The accuracy of the flood map was verified against the simulated flood data during the heavy rainfall event on the 24th of March 2015, which had a maximum rainfall intensity of 88 mm per hour. Results indicated that the area was flooded from 0.05 to 0.45 m, which agreed well with the actual flood data in the studied area.