Research On The Influence Of Shipping On The Water Environment Of Taihu Lake’s Inflow Channels And Its Control Countermeasures

Nowadays,shipping is the most important transportation method in Taihu Lake,which greatly promotes the economic development,while the oily sewage and domestic sewage produced by shipping will have a series of negative effects on the water environment of Taihu Lake.At present,the pollution situation of shipping in the Taihu Lake Basin is still unclear.Therefore,it is necessary to quantitatively assess the current situation of shipping pollution and provide data support for the water environment pollution of the basin,which is of great significance to the pollution control of Taihu Lake.In this study,15 main rivers flowing into the lake were seclected as the research objects,including pollution sources around the rivers,navigation of ships,and water quality compliance.Both Chendong River and Dapu River are from Dongjiu River,as a fourth class channel Chendong River has a large navigable volume,but Dapu River is an extra class channel,which is not navigable now.Therefore,they are selected as typical rivers for comparative analysis.Firstly,the water quality of Chendong River and Dapu River was monitored for one year and the monitoring indexes included COD_Mn,NH₃-N,TN,TP,SS,petroleum,organic matter,total nitrogen and available phosphorus in sediment.The correlation between the navigation volume and the concentration of various indexes in Chendong River was analyzed by SPSS software.Secondly,according to the"guidelines for the construction of port and ship pollutant receiving,transferring and disposal facilities",the pollution quantity of Chendong River is calculated.Based on the water quality of Chendong River during the period of navigation prohibition（restriction）in the Spring Festival of 2020,the MIKE 11 water quality model is built to simulate the water environmental capacity of Chendong River in the period of no navigation and normal period,and the comparative study is carried out.Finally,in order to analyze the influence of shipping sewage on the water quality of Chendong River national control section,different shipping sewage spots are set in MIKE 11 water quality model.Studies have shown that the COD_Mn、NH₃-N、TN、TP and aquatic ecological indicators of Chendong River and Dapu River are analogous,and the concentration of organic matter,available phosphorus and total nitrogen in the sediments of Dapu River are higher than those of Chendong River;Based on the comparison between the pollutant change trend of the two rivers and the traffic volume of Chendong River,it was not found that the navigable vessels had a significant impact on the water quality of Chendong River.The change rates of COD_Mn,NH₃-N and TP in Chendong River are less than 1.00%respectively under the conditions of no navigation and loading ships,and the overall difference is not significant;At the same time,when shipping sewage is discharged at different locations,the maximum water quality change rates of COD_Mn,NH₃-N and TP in Chendong River national control section are 0.0038%,0.0003%and 0.0010%respectively,which shows that shipping sewage is not the main factor affecting river water quality.Nevertheless,the control measures for shipping water pollution are still indispensable.In this paper,In order to further control the impact of shipping on the water environment of Taihu Lake Basin,some suggestions are put forward to ensure the shipping sewage treating equipment installation,improve the pollutant receiving system and supervision system,so as to provide new ideas for the water environment treatment of Taihu Lake Basin.