三峡水库香溪河库湾水华水动力调控初步研究

Preliminary study on hydrodynamic regulation of algal bloom in Xiangxi River Bay

针对三峡水库蓄水运行后支流库湾春季水华频现问题,利用CE-QUAL-W2模型建立了香溪河-三峡库区整体立面二维水动力数学模型,对三峡水电站不同开机数量和春季不同水文条件下的香溪河库湾流速进行了数值模拟。计算结果表明:香溪河上游来流量较小时,滞留区表层流速小于香溪河库湾水华的临界流速0.05 m/s;而香溪河上游来流量增大到合适的值时,香溪河滞留区表层流速可大于0.05 m/s;仅利用三峡电站小幅度日调节对支流库湾流速的改善效果十分有限,而利用干支流水库对香溪河库湾流速的联合调控效果明显,可控制三峡水库香溪河库湾水华爆发。

Aiming at the frequent algal blooms in spring at the Xiangxi River Bay after impoundment of Three Gorges Reservoir, a total 2D hydrodynamic mathematical model for Xiangxi River - TGP reservoir was established based on the CE - QUAL - W2 model. The velocity of the Xiangxi River Bay under different hydrological conditions and operating units of TGP hydrop0wer station in spring were simulated. The simulation shows that when the upstream flow of the Xiangxi River is small, the velocity of surface water in the retention area is smaller than the critical velocity 0.05m/s for algal bloom habitat; when the upstream flow increases to an appropriate value, the velocity of surface water in retention area could be greater than 0.05m/s; the improving effect on the flow velocity at the bay only by small scale daily regulation of TGP is very limited, while the improving effect on the flow velocity by co - regulation of the reservoirs on the main stem and tributary is obvious and the algal bloom in the Xiangxi River Bay can be controlled .