Applicability of Integrating a Flood Forecasting System and Data Dissemination in a Mobile Application for Early Flood Warning of the October 2021 Chao Phraya Flood

Abstract The lower Chao Phraya River Basin is a high flood-prone area which has often faced severe flooding damages. In order to, at least, mitigate somewhat such adverse flood impacts, a timely pre-warning system for the flood’s development is the first prerequisite. This requires, in addition to a reliable flood forecasting model, a timely dissemination of its predicted flood data. To that avail, a “Flood Forecasting System and Data Dissemination by Mobile Application”, called SWOC-FFC, for a big Chao-Phraya River flood has been developed which allows any mobile phone user to access the several days- ahead forecasted flood data in their area at a central Web server, allowing him some time for taking protective measures. SWOC-FFC, consists of 1) the HEC-RAS – hydrodynamic model computing up to 7 days-ahead flood levels and discharges along the Chai Phraya River which are then stored on (2) the Web server, to be transmitted to (3) the mobile application, where the flood data is displayed in various forms, among them a particularly appealing “realistic” river cross-sectional illustration and the flood heights annotated with three warning levels. SWOC-FFC application is tested for real operational forecasting of the large October 2021 flood and found to be very trustworthy.