Research on standard scheme of water quality at control section of river based on double weight theory：Take Zhanglou section in Pizhou city of Beijing-Hangzhou canal of south-to-north water diversion as example
Zhanglou section in Pizhou city of Beijing-Hangzhou canal of south-to-north water diversion is one of six sections in Jiangsu province which is included in the national examination.Comprehensive analysis of water pollution load, internal and external pollution rights has important significance for improving water quality of Zhanglou section. This article adopted the load ratio of pollution to computer the weights of water quality pollution at Zhanglou section by COD, NH3-N,TP and oil. On one-dimensional river model, the paper simultaneously calculated the weights of impact of pollution source within and out of the control region on water quality in different flow directions of every factor according to designed hydrology conditions and the boundary conditions of river. The results indicate that: ① the contribution rate of pollution of four pollutants to Zhanglou section is 19%~32%; ②COD, NH3-N and TP of the internal pollution sources accounted for 70% of the total pollutants,while oil type of that accounted for 40%; ③after the project of control pollution is put into effect, the water quality can meet the water quality standard of Class Ⅲ of surface water. The calculation method and results can provide the basis for the implementation of pollution control of basin level in Zhanglou section.