考虑水文变异的水库生态流量研究

为探讨水文变异对生态流量影响,确定最佳水库生态流量推求方法,针对尼尔基水库生态问题,采用Mann-kendall突变检测法、滑动T检验法和有序聚类法,结合序号总和理论和Spearman相关系数计算对水文时间序列作综合识别,确定水库发生水文变异年份为1963年和1999年。利用NGPRP法和逐月频率年内展布计算法分别计算天然状态、次天然状态、现状和不考虑水文变异条件下最小生态流量和适宜生态流量。参考Tennant法评价结果表明水库生态系统退化主要受人类扰动影响,观察次天然状态和不考虑变异状态下生态径流过程,最小生态流量占多年平均流量百分数相差9.21%和1.70%,适宜生态流量相差3.04%和1.47%。研究应更多考虑次天然生态径流过程,其最小生态流量仅可作为生态流量下限。

Study on ecological flow calculation under condition of hydrological variability

In order to explore the influence of hydrological variation on ecological flow, search for the best method of ecological flow of reservoir. Aiming at the ecological problems of Nilki reservoir,Mann-kendall mutation analysis method, Moving T method, Sequential clustering method, Serial number synthesis theory and Spearman correlation coefficient calculation method were used to do comprehensive recognition of the hydrologic time series, it was determined that the hydrological sequence of Nilki reservoir was changed in 1963 and 1999. Used the NGPRP(Northern Great Plains Resource Program) method and dynamic calculation method of monthly frequency, calculated suitable ecological flow, minimum ecological flow under the natural state, sub-natural state, current conditions,and without considering the mutation state. Evaluation results with reference to the Tennant method indicated that the degradation of the Nilki reservoir ecosystem was mainly affected by human disturbance,Observe the ecological flow process in the sub-natural state and without considering the mutation state,the difference between the minimum ecological flow rate and the average flow rate for many years was9.21% and 1.70%, the percentage of suitable ecological flow in the average flow for many years differed by 3.04% and 1.47%, it showed that the study should consider more the natural ecological runoff process, and its minimum ecological flow could only be used as the lower limit of ecological flow.