Risk transfer law of extreme water level events in river network area of the Pearl River Delta

In order to study the risk transfer law of extreme water level events in the river network area of the Pearl River Delta, based on the monthly water level data of 13 water level stations from 1957 to 2016, a risk transfer model of water level in the river network area of the Pearl River Delta was constructed using the pair-copula structure, and the risk transfer mechanism in space and the temporal variation law of extreme water level under different scenarios were analyzed. The results show that under low precipitation conditions, the probability of both forward (upstream to downstream) and backward (downstream to upstream) transfer of low water level risk in the river network area of the Pearl River Delta significantly increases. Under high precipitation conditions, the risk of forward and backward transfer of high water levels during the summer flood season is higher, while under low precipitation conditions, the risk of forward and backward transfer of low water levels during the winter dry season is higher. Affected by human activities, under high precipitation conditions, the risk of forward transfer of high water levels during the summer flood season of 1987-2016 was significantly increased compared to 1957-1986. Under low precipitation conditions, the risk of forward and backward transfer of low water levels during the winter dry season of 1987-2016 was significantly increased compared to 1957-1986.