降水量对湖山水库水质变化的影响研究

Study on the Influence of Precipitation on Water Quality Change in Hushan Reservoir

湖山水库是海南省文昌市重要地表水饮用水源地,其上游河段的COD和TP有超标现象,故确定库区污染物的输移扩散规律是提升水库水质的研究基础。以水库监测资料、DEM模型、遥感及GPS实测信息为基础,采用GIS技术将湖山水库边界和地形进行数字化处理,通过实测数据进行参数率定与模型验证,确定湖山水库的水动力模型和水质模型,将模型进行耦合联用,选取COD、TP、NH3-H进行数值模拟。在湖库风生流的基础上分析了降水量对水库水质演化过程的影响,并探究湖山水库水质演化规律。结果表明:1) 模型模拟的水动力和水质结果与实测结果较为吻合,表明模型选取参数合理。2) 水动力模拟方面,不同降水量条件下库区流场与流速分布规律相似,库区中部流速分布较均匀且变化较小。3) 水质模拟方面,各降水量条件下库区中部监测点和出库口监测点COD浓度变化规律相似,丰水期COD浓度明显高于平水期和枯水期。

The Hushan Reservoir is an important drinking water source in Wenchang City, Hainan Province. The COD and TP in its upstream section exceed the standard, so determining the transport and diffusion laws of pollutants in the reservoir area is the research basis for improving the reservoir water quality. Based on the monitoring data, DEM models, remote sensing and GPS measurement information, GIS technology are used to digitize the boundaries and terrain of the reservoir. Parameter calibration and model validation are carried out through measurement data to determine the hydrodynamic and water quality models. The models are coupled and combined, and COD, TP, NH3-H are selected for numerical simulation. The influ-ence of precipitation on the evolution of water quality in the reservoir is analyzed on the basis of the wind flow of the lake and reservoir, and the evolution law of water quality of the Hushan reservoir is explored. The results show that: 1) The hydrodynamic results simulated by the model are in good agreement with the measured data, indicating that the parameters selected by the model are appropriate. 2) In terms of hydrodynamic simulation, the distribution of flow field and flow velocity in the reservoir area is similar under different precipitation conditions, and the flow velocity distribution in the central reservoir area is relatively uniform and the change is small. 3) In terms of water quality simulation, the COD concentration of the monitoring points in the middle of the reservoir area and the monitoring point at the outlet of the reservoir area are similar under different precipitation conditions, and the COD concentration in the wet season is significantly higher than that in the flat water season and the dry season.