State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, China.
PLoS One. 2013 Jul 11;8(7):e68186. doi: 10.1371/journal.pone.0068186. Print 2013.
Three Gorges Reservoir (TGR) is one of the largest man-made lakes in the world. Since the impoundment in 2003, however, algal blooms have been often observed in the tributary embayments. To control the algal blooms, a thorough understanding of the hydrodynamics (e.g., flow regime, velocity gradient, and velocity magnitude and direction) in the tributary embayments is particularly important. Using a calibrated three-dimensional hydrodynamic model, we carried out a hydrodynamic analysis of a typical tributary embayment (i.e., Xiangxi Bay) with emphasis on the longitudinal patterns. The results show distinct longitudinal gradients of hydrodynamics in the study area, which can be generally characterized as four zones: riverine, intermediate, lacustrine, and mainstream influenced zones. Compared with the typical longitudinal zonation for a pure reservoir, there is an additional mainstream influenced zone near the mouth due to the strong effects of TGR mainstream. The blooms are prone to occur in the intermediate and lacustrine zones; however, the hydrodynamic conditions of riverine and mainstream influence zones are not propitious for the formation of algal blooms. This finding helps to diagnose the sensitive areas for algal bloom occurrence.
三峡水库（TGR）是世界上最大的人工湖之一。然而，自 2003 年蓄水以来，支流湾内经常出现藻类水华。为了控制藻类水华，深入了解支流湾内的水动力（例如，流态、速度梯度、速度大小和方向）尤为重要。本研究利用校准后的三维水动力模型，对一个典型的支流湾（即香溪湾）进行了水动力分析，重点研究了其纵向格局。结果表明，研究区域的水动力具有明显的纵向梯度，可大致分为四个区域：河流区、中间区、湖泊区和主流影响区。与纯水库的典型纵向分区相比，由于 TGR 主流的强烈影响，在口部附近增加了一个主流影响区。水华易发生在中间区和湖泊区；然而，河流区和主流影响区的水动力条件不利于藻类水华的形成。这一发现有助于诊断藻类水华发生的敏感区域。
