Development of a Flow Routing Model Including Inundation Effect for the Extreme Flood in the Chao Phraya River Basin, Thailand 2011

Abstract

In the second half of 2011, massive flooding in the lower part of the Yom and Nan River Basins and the Chao Phraya River Basin resulted in tremendous loss and adversely impacted on the livelihood, society, and economy of Thailand. The development of reliable and efficient prediction tools is important for prevent similar occurrences in the future. Consequently, this study thus aimed to develop an applicable distributed flow routing model including the inundation effect. A flow routing model using a kinematic wave equation was modified based on the concept of a diffusive tank model, which included the inundation effect. Overbank flow was estimated by using a broad crested weir equation. The inundation model had ten parameters that provided a good fit for observed and simulated discharge in 2011 at the C.2 Station with a Nash-Sutcliffe efficiency of 0.91.