Research On Water Environmental Capacity In GanFu Plain Irrigation Area

Water environmental capacity (WEC) means the maximum of pollutants carried by water body under certain water quality standards, and it is the pivotal technical parameter for total amount control of pollutants. In recent years, with the improvement of the control level of industrial point source pollution, non-point source pollution has become a major source of water pollution. The study on how to understand non-point source pollution scientifically and control it effectively has become urgent.Firstly, the research situation at present and the development trends of it at home and abroad are exposited comprehensively, and then the concept, characteristics and types are analyzed as emphases. Runoff coefficient method is used to estimate the runoff amount generated from rainfall based on a generalized manner of pollutants running into the river, and the estimation method of runoff amount and concentration of pollutants into the river is proposed combined with the definition of concentration and flow. Through the study of one-dimensional water quality model, BOD multi-river sections matrix model is used to simulate the water quality of canal sections, and it is realized through MATLAB simulation. According to the simulation results of drainage water quality, WEC definition method is used to estimate drainage WEC.In the research of application, firstly water pollution control units and canal calculation units are divided according to describing the general situation of irrigation canal system, socio- economic development and hydro-meteorological characteristics in the GANFU Plain Irrigation area. And though investigating to the pollution sources, pollutant amount into the river is calculated. Then drainage water quality is simulated based on monthly distribution of annual pollutant amount into the river, the WEC of TN and TP correspond to every canal unit are also calculated. At last, the pollutants reduction of every unit is determined based on calculation results of WEC. And though comparing the non-point source pollution control measures at home and abroad synthetically, reasonable management measures are developed combined with pollution sources of every canal unit out of pollution standard. Then linear programming method is used to optimize the combination of management measures at the target of minimum management cost.