Abstract:Based on four index parameters of tank storage capacity per unit area, adjustable storage capacity per unit area, channel storage capacity in river network and adjustable storage capacity in 1955, 1978, 1990, 2008 and 2016, the spatial and temporal variations of water system storage capacity in Jingnan Three Port of Yangtze River are compared and analyzed, and the relationship between water system structure and storage capacity is analyzed by correlation analysis method. The results show that: (1)The storage capacity of river network channel decreased by 26. 17% from 9 548. 52×104 m3 in 1955 to 7 049. 01×104 m3 in 2016. The adjustable storage capacity of river network gradually decreased from 4 696. 39×104 m3 in 1955 to 2 461. 13×104 m3 in 2016, a total decrease of 47. 59%. (2)There are obvious gradation differences between channel storage capacity per unit area of river network and adjustable storage capacity per unit area of river network. The adjustable storage capacity per unit area of the low-grade River(grades 1, 2 and 3)decreases the most, while the parameters of the four-grade and five-grade rivers decrease relatively low. (3)In the five periods, the storage capacity and adjustable storage capacity of the river network in each river system area have been declining. Among them, the decline of the Ouchi river system area is the greatest, and the lowest of the channel storage capacity and adjustable storage capacity per unit area of the river network is the Hudu River system area. (4)There is a significant positive correlation between water system storage capacity and the structure characteristics of river network, river hydrological connectivity, and connectivity degree of river network and river network connection at the level of 0. 01.