RESEARCH ON WATERSHED ECOLOGICAL ENVIRONMENT BASED ON MULTI-FACTOR REGRESSION ANAL YSIS

摘要

Water eutrophication will lead to a series of environmental problems,affecting regional production and life, and even threatening the whole regional ecosystem. In this study,by taking Dianchi Lake as the research object, considering hydrology, water quality, climate change, social economy, and other factors comprehensively, the principal component analysis method is used to screen out the main influencing factors for the occurrence of water blooms, and a multi-factor linear regression model of water bloom in Dianchi Lake is established. The most likely conditions for the occurrence of water blooms are deeply analyzed by response surface analysis test. Finally, the system dynamics model for the occurrence of water blooms is established to analyze the change trend of water blooms in Dianchi Lake under different improvement measures, which provides theoretical support for accurately predicting the occurrence of water blooms and formulating corresponding prevention and control measures. The test results show that, by using principal component analysis and multiple linear regression analysis, the significant factors affecting the occurrence of water bloom in Dianchi Lake are the average temperature T,average flow velocity Vr, average water flow OF, total nitrogen concentration Cy, nitrogen-phosphorus ratio CvCp and chemical oxygen demand emission Econ. The multiple linear regression equation of the occurrence of water bloom in Dianchi Lake is Y=125.47T-672.45Vp-1.63Op-4538.91Cn+135.47 C/ Cp-0.66Ecop. The results of response surface model analysis show that the order of the probability of water bloom is C/Cp >Ecop>Crw>Vr>T>O, and the most probable conditions for the occurrence of water bloom in Dianchi Lake are∶T=20.76℃℃，Op=36.53m³/s，VF =0.88m/s,Ecop=1.3lt/a,Cr =17.57mg/L,and CMCp=13.76.Finally,by constructing a dynamic model of water bloom in Dianchi Lake, the comprehensive prevention and control measures are put forward, which combine strengthening water resource dispatching and perfecting water ecosystem. The results of model analysis show that the average water flow, chemical oxygen demand discharge, total nitrogen concentration and nitrogen-phosphorus ratio in Dianchi Lake basin are slowly decreasing, the probability of water bloom is decreasing year by year, and the water environment in Dianchi Lake can be improved obviously.