洪湖水质时空变化规律及污染物汇入阈值研究

Spatio-temporal Variation of Water Quality and Threshold of Pollutants Inflow of Honghu Lake

为掌握洪湖水质时空变化规律、定量提出污染物汇入阈值,在构建洪湖水动力水质数学模型的基础上,模拟了丰、平、枯水期典型出入湖流量、污染物汇入情况下洪湖水质时空分布情况,采用试错法试算了各水期主要入湖口污染物汇入阈值。结果表明,蓝田、湖心A、桐梓湖、下新河等4个距离污染物汇入口较近的水质控制点,NH_(3)-N、TP浓度呈枯水期>平水期>丰水期,湖心B、排水闸、杨柴湖、小港等4个距离污染物汇入口较远的水质控制点,NH_(3)-N、TP浓度呈丰水期>平水期>枯水期;洪湖NH_(3)-N、TP浓度总体呈西北部、北部>中部>东部>南部,水质总体呈现由北向南变好趋势;主要入湖口污染物汇入浓度阈值呈枯水期>平水期>丰水期,但总体差别不大,NH_(3)-N、TP年汇入污染物总量阈值分别为2 537.77、116.53 t/a。研究成果可为洪湖水质达标管理提供参考依据。

In order to grasp the spatio-temporal variation of water quality and quantitatively propose the threshold of pollutants inflow of Honghu Lake, based on the construction of hydrodynamic and water quality mathematical model, the spatio-temporal distribution of water quality were simulated under the conditions of typical water and pollutants inflow and outflow in high, normal, and dry water periods. The threshold of pollutants inflow of main lake entrances in each water periods was calculated by trial and error method. The results show that the water quality control points close to the pollutants entrances such as Lantian, Huxin A, Tongzihu, Xiaxinhe, the concentrations of NH_(3)-N and TP in dry water period were higher than in normal and high water periods;Water quality control points far away from the pollutants entrances such as Huxin B, Paishuizha, Yangchaihu, Xiaogang, the concentrations of NH_(3)-N and TP in high water period were higher than in normal and dry water periods;The concentrations of NH_(3)-N and TP in Honghu Lake were generally higher in the northwest than in the north, in the middle, in the east and in the south, and the water quality was generally improving from north to south;The concentration thresholds of pollutants in the main lake entrances in dry water period were higher than in the normal and dry water periods, but the difference was not obvious;The annual total thresholds of NH_(3)-N and TP were 2 537.77 t/a and 116.53 t/a, respectively. The research results can provide a reference for the management of Honghu Lake’s water quality compliance.