香溪河春季突发水华事件的应急调度策略

Emergency Regulation Strategy for Sudden Algal Bloom Accidents of Xiangxi River in Spring

三峡水库蓄水后,春季香溪河中上游河段水华频发.通过调度方式改变香溪河回水区温差剪切分层流的运动特性,进而破坏藻类生长环境,能够有效抑制水华发生或降低水华暴发程度.基于此,结合实测资料建立了三峡库区-香溪河垂向二维富营养化模型,通过模拟详细探讨了调峰和蓄放水位对香溪河水华暴发过程的影响,并针对不同水平年分析了春季突发水华事件的应急调度空间.研究结果表明:当春季香溪河中上游河段有水华发生征兆时,可通过15,d左右的中期蓄水调度和日调峰运行有效降低藻类浓度,日均升水位超过0.1,m时,藻类浓度可下降11.5%以上.同时考虑入库径流过程、电站经济运行以及最大下泄能力等因素,较丰水年具有最大的调度空间.

Algal blooms happen frequently in the upper and middle streams of Xiangxi River after the impoundment of Three Gorges Reservoir. Different forms of thermal stratified flow exist in Xiangxi River owing to the driving force of water temperature difference between Yangtze River and Xiangxi River. Through regulation, the hydrodynamic characteristics of the thermal stratified flow can be changed and then the steady growth environment of algae de- stroyed, thus inhibiting the happening of algal blooms or reducing the bloom levels. Based on the above conclusion, a vertical two-dimensional eutrophication model of Yangtze River and Xiangxi River is developed with the measured data. The influences of peak load regulation, water storage and discharge on the water bloom process are modeled and analyzed, and the emergency regulation space in different level years is calculated. The results indicate that, if there is an obvious sign of water bloom accident in the upper and middle streams of Xiangxi River in spring, a water storage process of 15 days as a medium-term regulation, combined with peak load regulation, can be carried out to decrease the algal concentration effectively. When daily water level fluctuation is above 0.1 m, the algal concentration is de- creased by more than 11.5%. With inflow process, the economical operation of power station and the maximum dis- charge ability taken into consideration, the relatively wet year has the largest regulation space.