三峡库区草堂河库湾水动力特征

针对三峡库区蓄水后普遍存在的干流水体倒灌支流库湾的现象,为探究干支流水交换过程中的水动力特征,通过逐月(2012年9月至2013年7月)实地观测获取三峡库区中部典型支流草堂河库湾水动力参数及水体温度、浊度等数据,分析了水库运行各期干流与库湾的水交换情况及其对库区水环境的影响。结果表明:由于温度差异、干流惯性作用以及支流特殊地形等因素的影响,草堂河河口存在明显的双向水流结构,水库运行各期干支流交界面进出水体分布差异显著;特殊的河流走向使得全年多数月份草堂河与干流有效交换量高于其他典型支流;干流水体全年均能倒灌至库湾尾部,水库高水位运行期进出水体在河口呈上下分层结构且连续性较好,低水位运行期则以左右环流为主且连续性较差。

Study on hydrodynamic characteristics of Caotang Bay in Three Gorges Reservoir area

Water intrusion from the mainstream into tributaries frequently occurs since the Three Gorge Reservoir(TGR)impounded. To explore the hydrodynamic characteristics of the mainstream-tributary water exchange process, field observation was carried out to obtain the monthly data(from September 2012 to July 2013), including the hydrodynamic parameters, temperature and turbidity of the Caotang River, a typical tributary in the central area of TGR. Water exchange in different impoundment periods and its influences on water environment of the reservoir were analyzed. The results show that there is a clear bi-directional flow structure in the estuary of the Caotang River and the distribution patterns of the inward and outward flow varies in different periods at the mainstream-tributary interface. The effective flow exchange in most months of a year at the estuary of the Caotang River is higher than that in other tributaries due to the unique river orientation. The water in the mainstream can intrude into the end of Caotang Bay all year round. During the high water level operating periods, inflow and outflow in the estuary shows vertical stratification and good continuity while during the low water level operating periods, horizontal circulation occurs with poor continuity.