Research On Water Ecological Health Evaluation And Total Pollutant Control In Bosten Lake

Bosten Lake is the largest inland freshwater lake in China. It has such important functions as drinking, industry, agriculture, aquaculture, tourism, flood prevention and climate regulation and so on. As the main water source of Bayinguoleng Mongolian Autonomous Prefecture, Bosten Lake plays an irreplaceable role in the economic development and social stability of Xinjiang. In recent years, progressive deteriorationof aquatic ecosystems and overload call for urgent effective management and control. Based on objective and reasonable assessment of aquatic ecosystems health status, study about total quantity control of major pollutants is of great significances to water ecological and environmental improvement. In addition, it also provides necessary technical support and management basis for local authorities.The present study focused on Bosten Lake. Multi-level gray relational theory, one of the great methods treating problems of generalized uncertainty, was introduced into the system comprehensive evaluation. Water ecological health evaluation was conducted, in which combination of multi-level gray relational evaluation methods and trophic state index evaluation method was used. Result showed that the Bosten lake water ecological health status was medium, and composite index of water ecological health decreased each year in the past10years. Current pollutant load and emission into the lake in Bosten Lake basin were estimated reasonably according to the first national pollution census data in2010and Bayinguoleng Statistics Annuals. MIKE21hydrodynamic and water quality module were used to simulate the situation in Bosten Lake basing on collection and collation of materials about meteorology, flow, and pollutants concentration in water quality control points. Measured data was used for calibration and verification. Outlets around Bosten Lake were generalized as11main outlets. Response relation between outlets into the lake and water quality control points was built by MIKE21water quality module, and the response matrix was also constructed. Water environmental capacity of CODMn, TN, TP, TDS were calculated by water quality response model and linear programming coupled estimation, and their maximum allowable amount into the lake were3964.26t/a,420.89t/a,106.69t/a, and644844.71t/a, respectively, so as to meet the water quality goals. With the construction of comprehensive weighted Gene coefficient and the environmental economic efficiency parameters, pollution load allocation model based on multi-objective decision making was built in Bosten Lake, in which fairness and economic optimality were considered. This model was built under the condition of minimal weighted Gini coefficients and pollution abatement cost, and maximum environmental and economic gains. Optimal allocation method was gained by ideal point method. Corresponding measures for pollution control in Bosten Lake basin were proposed according to water pollutant load sharing results and abatement requirements.