Based on the monthly mean water level data of 15 hydrological stations in river network area of the Pearl River Delta from 1957 to 2016, a water level spatial dependence model was established using the pair-copula construction to generate samples, and the F-madogram method was used to quantitatively evaluate the spatial dependence of water level in river network area of the Pearl River Delta in different stages and distance ranges at different time scales. The results show that the spatial dependence of water level in the area with river network developing in the transverse direction is weaker than that in the 45° southeast direction in river network area of the Pearl River Delta, the spatial dependence of water level in wet season is significantly stronger than that in dry season, and the spatial dependence of water level at seasonal scale is weaker than that at annual scale. Due to the influence of human activities, the spatial dependence of water level in wet season from 1987 to 2016 was significantly enhanced compared with that in the period of 1957 to 1986 in a large distance range. In a small distance range, the spatial dependence of annual minimum monthly water level from 1987 to 2016 was significantly weaker than that in the period of 1957 to 1986, and the spatial dependence of annual maximum monthly water level from 1987 to 2016 was significantly enhanced compared with that in the period of 1957 to 1986.

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.