香溪河库湾春季营养盐空间差异性成因分析  

Causing analysis on nutrients spatial difference in Xiangxi Bay of the Three Gorges Reservoir

作　　者：蒋定国[1] 戴会超[1,2] 王冰伟[3] 刘伟[1] 

机构地区：[1]三峡大学水利与环境学院,湖北宜昌443002 [2]河海大学水利水电学院,江苏南京210098 [3]中国水利水电科学研究院,北京100038

出　　处：《水利学报》2013年第5期562-569,共8页Journal of Hydraulic Engineering

基　　金：国家杰出青年科学基金资助项目(50925932);国家重点基础研究发展计划(973)项目(2012CB417006);国家自然科学基金资助项目(51279047)

摘　　要：三峡蓄水后,香溪河库湾春季水体中营养盐分布呈明显的空间差异性,具体表现为总氮含量大致呈从上游到河口逐步升高的趋势,而总磷含量呈从上游到河口逐步降低趋势。为明确库湾水动力条件对库湾营养盐空间分布的影响,本文采用三维数学模型模拟了三峡蓄水后香溪河水动力场的分布,利用示踪方法分析了三峡蓄水初期香溪河库湾水动力场对春季营养盐时空分布的影响。结果表明,春季库湾近河口区域水体表现出明显的分层分向流动特征,长江干流水体与库湾水体间的交换作用显著,相应磷营养盐也随水流带出库湾,干流水体对香溪河库湾磷营养盐有明显的稀释作用,特殊的水动力条件是库湾营养盐空间分布差异性主要成因。研究可为三峡水库正常调度运行后香溪河库湾富营养化的控制和治理提供方法,也可为相似库湾营养盐的分布特征研究提供参考。Significant spatial variation is observed on the distribution of nutrients in the Xiangxi River in spring after impounding of the Three Gorges Reservoir. Evidences show that the total phosphorus is decreas-ing gradually from the upstream to the estuary, while the total nitrogen is increasing. To clarify the effects of the hydrodynamic conditions on spatial distribution of nutrient in the Xiangxi River, a 3D numerical model is constructed to simulate the flow field of Xiangxi River after impounding of the Three Gorges Reser-voir. Then a tracer method is introduced to analyze the hydrodynamic effects on the spatial and temporal distributions of nutrient in the Xiangxi River. The numerical results show that, in the spring, an obvious stratified flow field is found in the estuarine area. And strong/significant water exchanging is detected be- tween the mainstream of the Yangtze River and the bay, and with the exchanging of water the phosphorus is transported out of the bay and is further diluted by the main stream of the Yangtze River. From the re-suits, it can be concluded that the hydrodynamic conditions in the flow field of the estuarine area are the main cause of the spatial distribution of phosphorus in the Xiangxi Bay. This study provides a way to con- trol and govern the eutrophication in the Xiangxi River for the normally scheduled operation period of the Three Gorges Reservoir, and also provides a reference for the research on the distribution of nutrients in bays similar to the Xiangxi River.

关 键 词：香溪河库湾 水动力场 营养盐 空间分布 

分 类 号：X522[环境科学与工程—环境工程]