丹江口水库入库径流变化特征分析

为了揭示丹江口水库入库径流的变化特征及其对南水北调中线工程供水的可能影响,采用Mann–Kendall趋势检验方法、Markov过程和游程理论对丹江口水库实际入库径流序列的趋势性和丰枯变化特征进行了分析。结果表明:①丹江口水库入库径流呈下降趋势,1999～2017年年均径流量较1956～1998年减少了50.5亿m~3,主要是由于汛期径流减少导致的;②年入库径流出现丰水转丰水、丰水转枯水、平水转枯水、枯水转平水的状态居多,状态转移概率均大于40%;③入库径流发生连续4 a及以上丰、平、枯水年的概率较小,但仍需考虑水库遭遇连续枯水年的调度问题。

Study on variation characteristics of inflow runoff to Danjiangkou Reservoir

The seasonal and interannual variation of inflow runoff to Danjiangkou Reservoir, and their effects on the South-to-North Water Transfer Project were analyzed by using Mann–Kendall method, Markov process and runs theory. The results show that: (1) The annual inflow runoff volume displayed a decreasing trend. The average annual inflow runoff of 1999 -2017 decreased by 5.05 billion cubic meters compared with that of 1956-1998, which was mainly caused by the runoff reduction in flood seasons. (2) In terms of the annual inflow runoff transformations, the following types occurred more frequently: wet years to wet years, wet years to dry years, normal years to dry years and dry years to normal years, and the occurrence probabilities of those transformations are all more than 40%. (3) It rarely happens that wet years，normal years and dry years last 4 years or longer. However, it is still necessary to take continuous dry years into consideration in making reservoir operation strategies.