The Study Of Water Environment Capacity Based On MIKE21 Hydrodynamic And Water Quality Model

Water environment problem is getting worse in China.In recent years, environmental issues have been paidly more national attentions.As one of the fundamental policies to control pollution in China,total pollutant amount control is based on environment capacity, which is the maximum permitting mass loadings in some given water based on the water quality target. In a word, water environment capacity gives a scientific basis to the environment goal management, and provides important technology support for the control of total amount pollutant.Erhai lake is the foundation of social-economic development in Dali, Erhai lake governance is particularly important to local development. So It is very necessary to study Erhai lake water environmental capacity and control the Erhai lake pollution.In this paper, Hydrodynamic and water quality model is established in MIKE21 through investigating the basic situation of Erhai lake basin, pollution sources, hydrology and water quality. Based on the simulated water data, Erhai environmental capacity is calculated out by the sharing rate method, and Erhai environmental capacity is reduced according to erhai lake pollution load.The results show that the water environmental capacity of northern Erhai Lake is the least in the’II’glass water quality, the total amount of TN、TP、COD the river can take is respectively 1318、98、15596 t/a in wet year,1267、95、13550 t/a in average year,1077、89、10770 t/a in dry years.In order to ensure Erhai lake water quality, the north lake area can be used as the control points of water environmental capacity to reduce inflow rivers pollution of the Erhai lake.