Application Of SCEUA Algorithm In Tracing Groundwater Pollution

With the rapid development of economy, groundwater around the country is subject to the different degrees of pollution. But the pollution prevention, monitoring and repair system is not perfect in our country, so the groundwater environment for human beings survival suffered serious threats. In recent years, people are paying more attention to the groundwater pollution. The groundwater pollution has the character of concealment, so the key to prevent and control the groundwater pollution is to trace the source of contamination timely and effectively. However, at present the tracing method of groundwater pollution in our country is not mature enough and exists many shortages. This paper explores the tracing method of groundwater pollution.Optimization algorithm is an effective method of the research on groundwater pollution source. It is constantly updated development and different optimization algorithms have different advantages. So, after applied to many fields, it has reflected the great superiority and solved some problems that original traditional methods can not solve. In this paper, on the basis of a combination of SCE-UA optimization algorithm and ground water solute transport program(MT3DMS), the groundwater pollution traceable intelligent search model(SCEUA-MT3DMS) is established. First of all, the model of optimizing algorithm generates the pollution sample point, and then the groundwater contaminant transport numerical model simulates the seepage and migration of contaminants in aqueous medium using the pollution sample points. The predicted results of the simulation are used as the basis for further model selection. Through the pollution variation, reflection and evolution process, the optimization algorithm model from the many potential pollution source location automatically selects the most likely source location and intensity of pollutant emissions. After the completion of the groundwater pollution traceable intelligent search model, we always do simulation experiments under the different conditions, such as the single pollution source or double pollution source, the known position or unknown position, and the steady or unsteady flow. Generally in the evolution algebra T=40, complex number p=40, the true source of pollution were able to accurately located. Relative deviation D2 between the concentration pollution of the inversion and the true value were less than 2%. It can meet the needs of accuracy, verify the feasibility of the method, reflects the intelligent search model that can efficiently converge to the global optimal solution, locate the source location and concentration accurately, can be further applied to hydrological and geological conditions are more examples of pollution source inversion problem of complex.The groundwater pollution of Ningyang industrial area is relatively concentrated and serious, and the hydrogeologic data is relatively comprehensive. So the model is applied to the Ningyang industrial area as the big model of the actual case. Considering the existing problems in the regional model, we used a nested grid numerical simulation method, and the sub model realized for local refinement in the study area, reduced the interaction between the different chemical enterprise, improved the intelligent searching model of Groundwater Pollution Tracing inversion efficiency and inversion accuracy, and effectively shorten the operation time of the model. We selected suitable location in a chemical plant, monitoring wells and two characteristics of pollutants of polychlorinated biphenyls(PCB) and nitrate ions by analysis, then used the model to be inversion of positioning the pollution source location and pollutant emission concentration. The inversion results can be meet the demand of accuracy, also more in line with the pollution source of the actual position and concentration, through actual case, it reflected that the groundwater pollution traceable intelligent search model is accurate and reliable.Research shows that, through coupling the SCE-UA algorithm and the groundwater solute transport program(MT3DMS) to carry on the groundwater pollution inversion is an effective tracing method, can fast accurate positioning of pollution sources and achieves the purpose of tracing, embodies the correctness and feasibility of the model method.