基于时间序列法的滇池流域新宝象河污染风险预测

Forecast of the pollution risk confronted by the Dianchi Lake based on the time sequence from the point of view of its entering River Xinbaoxiang

入湖河流是滇池流域主要污染物的输送途径,为减少入湖污染负荷,需保证入湖断面水质达标。以新宝象河入湖河口2005—2017年的水质数据为基础,使用描述统计方法分析年度水质波动,采用单因素方差分析法对水温、降雨、污染物浓度进行季节性差异分析,并应用时间序列法对多年水质情况建立模型。结果表明,入湖污染最严重的时间是2007年,之后除总氮外其他污染物浓度迅速下降,直至2014年入湖河口水质达到地表水Ⅳ类标准,满足了规划的要求。河流的水温和区域降雨量具有显著的季节差异性,污染物浓度受降雨、回补水等各种因素的影响,总体呈现春季较高、秋季较低的现象。时间序列模型预测结果显示CODCr超标风险最大,为了预防超标的情况出现,提出了相应的防控措施,包括提升旁路治理能力、优化湿地调蓄、启动面源拦截等。

The given paper is to bring about an investigative analysis of the water quality status-in-situ of the lake Dianchi,Kunming,and the river it is connected with known as Xinbaoxiang during the period from 2005 to 2017. However,its research focus has been put on the analysis of the annual water quality fluctuation state via the Statistical Product and the Service Solutions（ SPSS）. As is well known,Dianchi is one of the most seriously polluted lakes in the country. The chief cause to lead to such serious unpleasant situation lies in the pollution of its original water source,Xinbaoxiang River,which should account for the serious on-load pollution predominantly. Furthermore,we have also done the single factor variance analysis of the seasonal changes of the water qualities,including its temperature variation,the rainfall impact,the chemical oxygen demand（ COD）,the total nitrogen（ TN）volume,the biochemical oxygen demand（ BOD5）,the ammonia nitrogen（ NH3-N） and the other pollution effects. Seeing the need,we have established a water quality situation model through mathematical analysis and pollution degree evaluation,in addition to the temporal consequential analysis. The effect and the accuracy of the model has been confirmed through comparison of its suitability with the measured data in 2017. And,then,the validated model has been turned to forecast the successive risks of the pollution factors in the future.As a result,we have found that the water quality of the said river turning to be the worst in 2007 and since then,a lot more pollution control projects has been accomplished in 2014. Thus,consequently,things have turned to be a lot better with the water quality recovered to Grade Ⅳ（ the surface water）,which should be said coming up to the demand of the water quality control objectives. Thus,the results show that the water temperature and the needed rainfall may have had significant seasonal variation,whereas the concentration rate of the pollutants may not have had noticeable seasonal variation due to the effects of the rainfall and the other related factors. On the general term,the pollution rates are usually higher in spring and turn to be lower in autumn. The forecast results by means of the time sequence method show that the risk likeliness rate with the CODCr method would like to be the highest. In order to prevent from such kinds of risk,it would be necessary to take a series of preventive and control measures,including purification of the storage functions of the wetland,setting up of a comprehensive non-point source pollution interception and heightening of the capacity of the bypass pollution control projects.