香溪河水质的平面二维数值模拟

Application of two-dimensional water quality model in Xiangxi River

三峡工程建成后改变了三峡库区及长江支流的水动力条件,对水生态环境产生重要影响,导致近年来水华现象频繁发生。该文采用空气动力学数值格式的平面二维水质模型对香溪河的水流水质进行了模拟研究,并采用2007年9月～10月和2008年6月～7月香溪河的水质监测数据对此模型进行了率定和验证。计算结果表明:该模型可以准确地模拟香溪河水流水质时空分布,并验证了流速是诱发香溪河水华发生的重要因素,且0.03 m/s为香溪河水华发生的临界流速;香溪河的营养物质浓度在水华期间处于动态变化中,特别是上游河段的浓度受来流所含营养物质浓度的影响明显,此研究结果可为三峡库区水质管理提供相关科学依据。

Dramatic change in hydrodynamic and aquatic conditions has led to an increasing occurrence of algal bloom in the Xiangxi River, a typical tributary of the Yangtze River near the Three Gorges Project. Nutrients＇ transport and evolution in this river was simulated by using a two dimensional water quality model with aerodynamic numerical scheme which was validated and verified against filed data of 2007 and 2008. Simulation resul^ts reveal that algal bloom occurs when flow velocity falls less than 0.03 m/s. The dynamic process of nutrient evolution during an algal bloom is closely related to the incoming load.