| The study show that water quality have significant effects by the construction of the Changsha Hydropower Project, through the water quality monitoring by the state environ mental quality standards for surface water as the evaluation basis, evaluating th e impact on water quality by the experimental data. The study relates water qu ality changes in the state and the mathematical model, computer technology to gether, and establishes the early warning model, can significantly prominent qu ality changing trend and quality problem through the water quality variation ca rrying on the analysis, and then determining the main pollution sources and po llution types, for the study of basin water quality of major changes to providin g early warning tools, the watershed environmental management providing decis ion-making basis at the same time.This study selects the Xiangjiang of6sections of multiple indices in Changsha a bout16indexes of water quality monitoring, detection method uses the nationa1standard method as far as possible, and controls the experimental quality. Dur ing the evaluation of the impact of stage, through the comprehensive fuzzy eva luation method, the analysis shows that:the monitoring period, Xiangjiang Cha ngsha water reached the â…¢ class of the national quality standard, the main pol lutants are nitrogen, phosphorus pollutants, the sum of the exceed the standard rate of total nitrogen in each section achieves nearly80%, the concentration of the total phosphorus only with class IV water quality requirements after the st arted to build of reservoir environment, the chemical oxygen demand target als o had exceed the standard limitation, the highest exceed the standard rate of42%, people needs to pay attention to the risk of cadmium and mercury polluti on which still exists, such as mrcury highest value reached0.0056mg/L. At the same time, the study expatiates that the changes of the basin of the natural, e cological, social environment will have a great impact by the project in the co nstruction period.In order to response the water quality changes of Xiangjiang in Changsha at the future time as far as possible, the study uses the Matlab software to p rocess the monitoring data for the establishment of a S-P model based BOD-D O by biochemical model; On this basis, the eutrophication model contains the water quality prediction model of the total nitrogen, ammonia nitrogen and th e phosphorus; The study due to the heavy metal pollution is prominent in Xia ngjiang, establishing the simplified soluble heavy metal water quality model. T he three model as a basis, the membership degree method to obtain the weight of each index in combination with water quality early warning by the basis o f the theory, as determining water quality warning degree, the study establishes the water quality early warning model on the Xiangjiang in Changsha. By pre-alarm scheme analysis, at present, each section in addition to except the Heish ipu section and the Dupujiangge section for light alarm, the remaining sections are the moderate alarm in Changsha segments of the Xiangjiang river.Finally, the study also provides the new countermeasures for the water env ironmental protection during the Changsha Hydropower Project of the establishment and storage period, and the corresponding measures to control water pollution. |
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