Author(s): K. Phothiwijit; C. Chinnarasri
Linked Author(s):
Keywords: Drainage system; Flood inundation; 1D-2D linked model; Shortcut Canal; Tha Chin River
Abstract: This research aims to study the efficiency of drainage system at the downstream of the Tha Chin River under the government's flood protection policy of government. Due to a number of S-shaped curves, a shortcut canal is proposed to be constructed in the downstream of the Tha Chin River at Nakhon Chai Sri District to improve its drainage flow velocity to the Gulf of Thailand. The ISIS 1D-2D linked model is used to simulate the flood inundation with the digital elevation model in the part of river adjustment. The upstream boundary condition, which is the runoff at the basin inlet, is calculated from flow hydrograph data in Thailand flood 2011. The downstream condition is the time series of the outflow to the sea in November 2011. The resolution of digital elevation model is 30 meters and cross sections of river are taken every of 5 kilometers along the river. The run time is ended when the outflow hydrograph at the outlet of the basin is completed. The model is calibrated using the 2011 flood stain and the flood area images taken by remote sensing technique to compare and adjust the model results of flood inundation depths and area parameters. It is found that when the shortcut canal is added in the system, it shows a high potential of drainage velocity to the sea. The flood depth and flood duration in the downstream of the river basin are reduced significantly. A flood risk map after the shortcut canal is operated is presented and flood management practices are proposed.
Year: 2014