Flash Flood Early Warning Indicators for South Branch of Censhui Watershed (PAP014403)
Changzhi Li, Hong Wang, Meihong Ma, Xiaotao Cheng
Flood forecasting and early warning systems
Using hydrological modeling technique with detailed sub-basin delineation, this study introduces basic concept and methods of analyzing warning indicators for flash flood early warning. Taking South Branch of Censhui watershed in China as an example, 3 typical early warning indicators for flash flood dynamic early warning were investigated. The primary indicator, critical rainfall, was analyzed at 3 early warning stations located inside the watershed, and other two important indicators, warning discharge threshold and warning rainfall duration, were also estimated using the results of critical rainfall. This research illustrates that detailed watershed characteristics can be modeled in-depth by further delineate the watershed into smaller sub-basins to simulate spatial distribution of various basin parameters. The resulted runoff and flood hydrographs show better accuracy at all 3 early warning stations. It further confirms that time of concentration of a watershed is an important factor to warning rainfall duration, and the antecedent soil moisture condition of the watershed has significant impact to the critical rainfall.