滇池东南岸农业和富磷区入湖河流地表径流及污染特征

应用聚类分析与因子分析方法,通过8次常规监测,对滇池东南岸10条以农业面源和受磷矿开采区影响的入湖河流的地表径流及其水质污染特征进行了分析,并探讨了其空间差异性。在南岸选取降雨过程相同的3条河流,开展暴雨径流监测,探讨污染物在降雨过程中的流失特征。结果表明,新宝象河的平均流量为2.6 m3/s,占总入湖流量的26.5%;总氮、总磷、化学需氧量、悬浮物是滇池的主要污染指标,许多河流均已严重超标。河流水质在空间上可分为3类,具有明显的空间差异性。总氮、总磷、溶解磷、硝态氮对水质污染的贡献率达到了53.636%,氮、磷含量是河流水质污染的主要贡献因子。降雨条件下化学需氧量、悬浮物浓度增长迅速,流量、悬浮物与大多数水质指标均有相关性,磷矿开采对河流水质的影响在降雨条件下更加明显,其悬浮物浓度在降雨条件下比只受农业面源影响的河流最高高出1.9倍。

Surface Runoff and Pollutants Characteristics of Inflowing Rivers in the Agricultural and Phosphorus-Rich Region on the Southeast Coast of the Lake Dianchi

Based on eight times monitoring, this study analysed the characteristics of surface runoff and pollutants loss in 10 rivers on the southeast coast of Lake Dianchi. Water quality of these rivers are mainly influenced by agricultural non-point source and phosphate exploitation. In order to explore the characteristics of pollutants loss during rainfall events, three rivers which have the same rainfall process on the south coast of Lake Dianchi were selected for rainfall-runoff monitoring. The results showed that the mean discharge of Xinbaoxianghe river was 2.6 m³/s which occupied 26.5% of the total discharge flowing into the lake. TN,TP,COD and SS which had seriously exceeded standard values in many rivers were the major load for Lake Dianchi pollution. River water quality could be classified into three classes and showed a significant spatial differentiation. The contribution rate of TN,TP,DP and NO₃^--N was 53.636%. This showed the quantity of N and P was the main contribution factors to river pollution. The concentration of COD and SS could increase rapidly especially during rainfall. Discharge and SS had correlation to most water quality indicators. The influence of phosphate exploitation on river were more obvious during rainfall, its concentration of SS during rainfall could be 1.9 times higher than rivers which only influenced by agricultural non-point source.