The Nansi Water Environmental Quality Assessment

South To North Water Transfer Project is a exceptionally large-scale infrastructure project for the problem of serious water shortage in Northern China. As an important transmission channel and storage lake in Shandong Province, Nansi Lake is facing a great challenge to guarantee the water safety in this project. Although the water quality of the lake has been improved through treatments of the recent years, it is still far from the environmental quality standard for theâ…¢class surface water. With the day of water transferring for the East Route Project of South To North Water Transfer coming closer and closer, it is of ultimate urgency to improve the water quality of Nansi Lake to meet theâ…¢class standard of ' Environmental quality standard for surface water' .Basing on systematic theory, a comprehensive investigation on current situation of economy, nature and society in Nansi Lake basin is conducted in this paper, according to which a plan is drafted to monitor the water quality of the lake and rivers comprehensively. Meanwhile, the cause for the contaminations in Nansi Lake basin are analyzed in this paper by evaluating and analyzing comprehensively the water quality of Nansi Lake before water transferring and spatial distribution characteristics of the main contaminations. According to these analyses, respective countermeasures against those water pollutions are brought up on the basis of the advanced technologies at home and abroad of water pollution prevention and control. The main contents of this research are as follows:1) A comprehensive evaluation model is established in this paper for Nansi Lake basin by studying the BP Nerve Network which is based on nonlinear theory. By applying MATLAB, the water quality of the lake and rivers is comprehensively evaluated. Furthermore, the over contaminated zone and the causes for the pollutions are analyzed by applying Surfer to visualize evaluation results.2) Using Remote Sensing methods to monitor the water quality has many advantages such as being prompt, highly-effective, information-abundant, and boundless etc. In this paper, the inversion models of the typical water quality was presented by analyzing correlation between TM images of Landsat 5 and local measured values of chlorophyll-a and suspended solid. It was used to evaluate the water quality of Nansi Lake. In addition, the eutrophication level of Nansi Lake was evaluated by Tropic State Index (TSI).3) In order to do further study on main factors of influencing the water quality of Nansi Lake, Surfer is adapted in this paper to visualize the spatial distribution of concentration of COD_Cr,NH₃-N,TP,TN and analyze the distribution of the pollutions, which will contribute to Nansi Lake Basin Pollution Control.4) pollution control countermeasures for Nansi Lake basin are presented in this paper by analyzing the current situation of nature, society and economy, pollution sources as well as preventing and controlling technologies over water pollution at home and abroad. Moreover, this paper provides technological support for pollution control in East Route Project of South To North Water Transfer Project in combination with the water quality evaluation results and pollution factors.