鄱阳湖环湖灌区枯季缺水量分析及对策建议

In recent years, due to the influence of a series of human activities around the river basin represented by the Three Gorges Dam, the dry season duration of Lake Poyang was prolonged and early drawdown of water level was observed. This leads to a series of ecological and livelihood issues. To investigate the water shortage of irrigation around the lake, this paper analyzed the water level of Xingzi Station from 1953 to 2018 by applying eleven probability distribution functions. The Wakeby distribution was selected as the theoretical distribution after comparison. Both the mean annual water level and mean monthly water level during the dry season under a 90% guarantee rate were obtained. Based on the mean annual water level over the years, the representative hydrological year was selected to analyze the supply and demand of water resources, thus the water shortage was obtained. Consequently, the quantitative relationship between water shortage change of the irrigation area and water discharge change of the main channel of Changjiang River was established, and the countermeasures were discussed. The results show that the water shortage (under 90% guarantee rate) of irrigation area around Lake Poyang has accordingly reached 226 million m³, 212 million m³, 57 million m³, 58 million m³, 55 million m³ and 25 million m³ from September to February of the next year, since the operation of the Three Gorges Dam in 2003. The solution to meet the water demand of the irrigation area by regulating the water discharge of the main channel of Changjiang River is only applicable to the situation when the water discharge from the 'Five Rivers' decreases in September and October. Therefore, to restore the water level of Lake Poyang and its process, other more effective means are needed.