大坝下游河段的河流生态径流调控研究

了分析大坝工程对河流径流情势的影响，以三峡大坝下游河段的宜昌站为例，计算了三峡坝下河段的生态水文季节、生态需水和其它径流情势特征参数。计算结果表明，长江宜昌江段枯水期为1~3月份、副汛期为4~6月份和10~12月份，而洪水期为7~9月份；枯水期、副汛期和洪水期的最小生态需量占同期来水总量分别为24%~27%、30%~50%和30%~45%；适宜的生态需水在枯水期、主汛期分别占同时期来水总量为30%~42%、50%~70%；四大家鱼和中华鲟产卵、繁殖期内的适宜生态流量范围分别为 6 540~12 700 m3/s 和 16 300~9 130 m3/s，大约占同时期来水总量的50%~70%;涨水次数平均值分别为5.3和3.4，落水次数平均值分别为50和5.1等，这为三峡水库在四大家鱼和中华鲟产卵、繁殖期内的调度提供了保护的依据。〖

ON ECOLOGICAL RUNOFF ADJUSTMENT IN DOWNSTREAM WATERS OF DAMS

In this paper the influence of dams on flow regime is analysed.Taking Yichang hydrological station located in the downstream of Three Gorges Dam as an example,eco hydrological season,ecological water requirement and other runoff regime characteristic parameters of Yichang hydrological station were calculated.The results show that dry season is from January to March,subordinate flood season is from April to June and from October to December,and flood season is from July to September;minimal ecological water requirements in the dry,subordinate flood and flood season occupy 24%~27%,30%~50% and 30%~45% of the same period total water quantity,respectively；optimal ecological water requirements in dry and flood season are 30%~42% and 50%~70%,respectively;optimal ecological flows of four major Chinese carps and Chinese sturgeon in the spawning period range from 6 540 m3/s to 12 700 m3/s and from 9 130 m3/s to 16 300 m3/s,respectively,almost occupy 50%~70% of the same period total quantity;average swelling times are 53 and 34,and average falling times are 50 and 51 respectively,and so on.The study provides foundation knowledge for Three Gorges Reservoir operation in the spawning period of four major Chinese carps and Chinese sturgeon.〖