不同水期洱海氮磷时空变化规律

Temporal and Spatial Variations of TN and TP in Different Water Periods of Erhai Lake

为了掌握洱海特征污染物入湖后在湖区的迁移规律,基于环境流体动力学模型EFDC,建立了洱海三维水质数学模型,并利用2015年、2016年的水文水质监测数据对模型进行了率定和验证。利用建立的洱海三维水质数学模型,模拟分析了不同水期、不同氮磷污染源浓度汇入条件下的洱海湖区总氮(TN)、总磷(TP)时空演变规律。结果表明:不同水期、不同氮磷污染源浓度汇入条件下的TN、TP分布规律类似;丰水期湖区TN、TP浓度总体上大于平水期和枯水期,高浓度汇入条件下的湖区TN、TP浓度总体上大于中浓度和低浓度;不同水期、不同氮磷污染源浓度汇入条件下洱海湖区TN、TP平均浓度差别不大,分别约为0.50 mg/L和0.03 mg/L;空间分布上,洱海湖区北部TN、TP浓度较高,近岸区域、湖湾的TN、TP浓度高于湖区。研究结果可为保护和治理洱海提供参考。

In the aim of understanding the migration rules of characteristic pollutants in the Erhai Lake,a 3D mathematical model of water quality of Erhai Lake was established using the environmental fluid dynamics model EFDC,and was calibrated and verified by the hydrology and water quality monitoring data of 2015 and 2016.The model was employed to simulate the temporal and spatial variations of TN and TP in the Erhai Lake region in different water periods or with different incoming concentrations.Results reveal that the distributions of TN and TP in different water periods and with different incoming concentrations are similar:the concentrations of TN and TP in the lake area in wet season are generally higher than those in flat and dry seasons;the concentrations of TN and TP under high incoming concentration is higher than those under medium and low incoming concentrations.The average concentrations of TN and TP in the Erhai Lake area in different water periods differ slightly with those under different incoming concentrations,about 0.50 and 0.03 mg/L,respectively.In terms of spatial distribution,the concentrations of TN and TP in the north part of Erhai Lake area are relatively high,and the concentrations of TN and TP in coastal areas and lake bays are higher than those in the lake area.The research results offer reference for the protection and management of Erhai Lake.