Study of risk and early warning index of rainstorm waterlogging in Wuhan City

Abstract

In the present study, rainfall thresholds creating waterlogging and a waterlogging risk map were established by analyzing waterlogging monitoring and rainfall observation data in Wuhan City from 2011 to 2016. The study found that 1) Wuhan City rainstorm waterlogging occurred during the summer months, mostly in June and July, accounting for 90% of the total waterlogging; 2) Waterlogging generally occurred along the rivers and lakes near low-lying areas; 3) The longest continuous waterlogging time was greater than 10 h and the deepest water depth was 2 m; 4) The greater the cumulative rainfall over 24 h, 12 h, 6 h, or 3 h, the more severe the waterlogging was; 5) The thresholds of continuous 24 h rainfall of mild, moderate, and severe waterlogging in Wuhan City were 123, 163, and 196 mm, respectively, while 12 h cumulative rainfall thresholds were 86, 145, and 187 mm, respectively. The 6 h cumulative rainfall thresholds were 68, 113, and 135 mm, respectively, and 3 h cumulative rainfall thresholds were 40, 74, and 94 mm, respectively. If the city's drainage capacity increases, the cumulative rainfall of waterlogging warning indicators will also need to be adjusted.