Author(s): Theerapol Charoensuk; Narongrit Luangdilok; Ticha Lolupiman; Watin Thanathanphon; Piyamarn Sisomphon
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Keywords: Urban; Radar; Bangkok; Flood; Early warning system
Abstract: Urbanization is considered as one of the most significant anthropogenic alterations to the land cover change. There are a lot of effects from urbanization, for example population growth, building construction, and rapid occurrence of urban runoff. Bangkok, the capital city of Thailand, has its notorious for frequent flooding. Apart from heavy rainfall becomes more extreme than in the past, land use change due to rapid economic growth is one of the key factors that affect the city planning. The drainage system i.e., pipes and diversion channel to the tunnel is full with sediment and debris and not capable of draining the urban runoff in time. In general, Bangkok’s drainage system is designed based on rational formula. This study presents the development of urban flood early warning system by applying flood threshold estimated from rational formula using observation and 1 hr. now-casting from weather radar data. The system is designed with data overlay concept by integrating real time observation, now-casting data and calculated flood threshold. Flood risk area is identified and alerted for warning. Bangkok’s flood management polder is divided into 22 zones or polders according to flood characteristic and operational management i.e. dike. In this study Chatuchak polder was selected as a pilot area. The calibration has been done using the flood events from 2017-2018. The accuracy was found satisfactory with 70% effectiveness.
Year: 2020