Recovering the History of Groundwater Contaminant by hybrid Simplex-Simulated Annealing Method

Abstract:

To recover groundwater contaminant source’s release history according to the obtained monitoring data belongs to groundwater inverse problem. In this study, a hybrid simplex-simulated annealing method is adopted and incorporated with the analytical solutions of the contaminant transport equation to recover the history of groundwater contaminant. The hybrid SMSA algorithm incorporates the deterministic search pattern of simplex method and the global probabilistic search mechanism of simulated annealing algorithm, and has proved to be a robust hybrid optimization algorithm. Meanwhile, the analytical solution to contaminant transport equation proposed by Yeh is adopted and realized in this study, for the characteristics of this analytical solution are reliability, easy programming and scalability. As shown by the calculation results, the recovered release history obtained by hybrid SMSA method and Yeh’s analytical solution is well reproduce the real process of contaminant release. It is further concluded that hybrid SMSA method and its incorporation with Yeh’s analytical solutions can be widely used in reconstructing the release history of groundwater contaminant.