考虑水文变异的漾弓江干流生态流量计算

Calculation of ecological flow in Yanggong River trunk stream considering hydrological variation

气候和人类活动改变了河道径流的一致性,因此考虑水文变异的河流生态流量计算对保护河流生态系统具有现实意义。以云南省漾弓江为例,采用4种时间序列检验法对三义断面和金河断面1959~2019年径流序列进行突变检验,利用平水年逐月最小生态径流法和逐月频率年内展布法计算不同时期的生态流量,并用改进的Tennant法进行评价。结果表明:变异年份确定为1997年和2011年,计算得到两断面在天然状态、次天然状态、现状和不考虑水文变异条件下最小和适宜的生态流量,次天然状态的生态流量更利好河流生态系统,现状河流生态系统遭到了一定的破坏,不考虑变异的生态径流过程与天然状态接近。生态流量的确定应更多考虑天然状态的生态径流过程并参考次天然状态。最后提出了2020~2030年漾弓江生态流量保障工作目标及建议。

Climate and human activities have changed the consistency of river runoff,so the calculation of river ecological flow considering hydrological variation is of practical significance for the protection of river ecosystem.Taking Yanggong River as an example,four time series inspection methods were used to test the abrupt change of runoff series of Sanyi section and Jinhe section from 1959 to 2019.The ecological flows in different periods were calculated by using the monthly minimum ecological runoff method and the monthly frequency annual distribution calculation method,and the improved Tennant method was used to evaluate the runoff.Results showed that the variation years were 1997 and 2011;the minimum and appropriate ecological flow of the two sections were calculated in a natural state,sub-natural state,the present state and the state of not considering hydrological variation.It was found that the ecological flow of the sub-natural state was more favorable to the river ecosystem.The ecosystem of the present state was of certain destruction.The process of ecological runoff without considering variation was close to the natural state.In order to determine the ecological flow scientifically,more consideration should be given to the ecological runoff process in the natural state and the sub-natural state.At last,the work objectives and suggestions for the ecological flow of Yanggong River in 2020~2030 should be put forward.