Abstract
A pluvial flash flood is rapid flooding induced by intense rainfall associated with a severe weather system, such as thunderstorms or typhoons. Additionally, topography, ground cover, and soil conditions also account for the occurrence of pluvial flash floods. Pluvial flash floods are among the most devastating natural disasters that occur in Taiwan, and these floods always /occur within a few minutes or hours of excessive rainfall. Pluvial flash floods usually threaten large plain areas with high population densities; therefore, there is a great need to implement an operational high-performance forecasting system for pluvial flash flood mitigation and evacuation decisions. This study developed a high-performance two-dimensional hydrodynamic model based on the finite-element method and unstructured grids. The operational high-performance forecasting system is composed of the Weather Research and Forecasting (WRF) model, the Storm Water Management Model (SWMM), a two-dimensional hydrodynamic model, and a map-oriented visualization tool. The forecasting system employs digital elevation data with a 1-m resolution to simulate city-scale pluvial flash floods. The extent of flooding during historical inundation events derived from the forecasting system agrees well with the surveyed data for plain areas in southwestern Taiwan. The entire process of the operational high-performance forecasting system prediction of pluvial flash floods in the subsequent 24 h is accomplished within 8–10 min, and forecasts are updated every six hours.
Highlights
The most fundamental requirement for a successful flash flood simulation or prediction is a large amount of high-resolution topographic data [10,11,12,13,14,15,16,17,18,19,20,21,22,23]; the light detection and ranging (LiDAR) technique has been widely applied in creating a three-dimensional set of points for high-resolution digital elevation model (DEM) with an accuracy of up to 0.1 m in the vertical direction
Two historical events with large-scale inundation that occurred in the plain areas of Tainan city in June 2005 and August 2009 were hindcasted by the SCHISM-FLOOD, in which the former was caused by torrential rain, and the latter was due to Typhoon Morakot
The 1.25-km resolution rainfall grids within or partially overlapping Tainan city served as meteorological inputs for the SCHISMFLOOD and Storm Water Management Model (SWMM) to forecast pluvial flash floods
Summary
Bank Group [1] indicated that natural hazards, such as floods, droughts, tsunamis, and earthquakes, continue to cause hundreds to thousands of injuries, tens of thousands of deaths, and billions of dollars in economic losses every year worldwide. Among these hazards, floods are the most common natural disaster that occur on the planet, affecting the lives of hundreds of millions of people around the globe and causing approximately. The first type is coastal floods ( known as surge floods), which occur in areas that lie on the coast or large water bodies (e.g., large lakes). Pluvial flooding can occur in any area, including higher elevation areas, that lie above coastal and riverine floodplains
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
