二滩水电站运行后对雅砻江下游河流水文情势的影响分析

Influences Analysis of Ertan Hydropower Station Operation on Flow Regime of Lower Yalongjiang River

为评估二滩水电站运行后对下游雅砻江水文情势的影响程度,针对雅砻江下游小得石水文站1958～2012年期间逐日流量变化情况,采用变化范围法（RVA）求得水文变动指标（IHA）中33个水文参数的改变及水文改变程度。结果表明,二滩水电站运行后,其下游雅砻江月平均流量变化的改变不大,年最小流量的改变有所增加,年最大流量变化不大;年最大流量、年最小流量的出现时间均由建库前的30日左右增加到90日左右,偏差较大;年高低流量的频率升幅较大,但持续时间略微减少;涨水率有所上升;落水率有所下降。最终根据水文综合改变度评价雅砻江河流水文情势总体改变度为68.31%,这表明二滩水电站的运行对下游小得石水文站的水文情势的影响为高度改变。

To evaluate the influence of operation of Ertan hydropower station on the flow regime at the lower Yalongjiang River,the range of variability approach was used to calculate the changes of the 33 indicators of hydrologic alteration with the daily observation data of the Xiaodeshi hydrological station in the lower Yalongjiang River.The result shows that after the operation of Ertan hydropower station,the monthly average discharge variation in the lower Yalongjiang River is not obvious.The minimum annual discharge variation increases and the maximum annual discharge do not change.The appearance times of minimum and maximum annual discharge increase to 90 days from 30 days before built reservoir.There are large deviations.The frequency variation scope of annual discharge is increased but the duration time is decreased.The risen water ratio is ascended while drawdown water ratio is descended.According to the comprehensive IHA,the total change degree of flow regime in Yalongjiang River is 68.31%.It shows that the operation of Ertan hydropower station highly changed the flow regime of the Xiaodeshi hydrological station in the lower Yalongjiang River.