The Dynamic Changes in the Storage of the Danjiangkou Reservoir and the Influence of the South-North Water Transfer Project

Danjiangkou Reservoir is water source of Middle Route Project of the South-to-North Water Diversion (SNWD) Project, research on the dynamic changes in the water storage within the Danjiangkou Reservoir constitutes an important guide for reservoir water volume management practices. A practical method for estimating the water storage and its dynamics was proposed in this study based on inundated areas from Moderate Resolution Imaging Spectroradiometer (MODIS) observations between 2000 and 2016. The results show that the mean Danjiangkou Reservoir water storage was 10.548 billion m(3) year(−1). Significant seasonal changes (ρ < 0.01 in t-test) were observed with annual minima (~9.610 billion m(3)) occurring between February to July and annual maxima (~11.514 billion m(3)) occurring from August to the following January. Based on the monthly changes in the probability of the water supply, the guaranteed rate of water supply in the second half year (July–December) was higher than that during the first half year (January–June). The water supply in May was greatly deficient. In addition, the full guaranteed rate of the water supply over the past 17 years only accounted for 17.6%. Therefore, reservoir management practices should reduce the water released prior to May and reserve enough water according to the demands of water receiving areas to improve the efficiency of water resource utilization.