University of California Water Resources Center

A methodology for the restoration and cleanup of existing subsurface contaminated sites and for the containment of pollutants is developed. The remediation problem is posed as an optimization model where the rates and locations of pumping and injections are to be determined given the characteristics and extent of the contamination plume. The solution of the remediation problem is based on the econometric method of feedback control coupled with ground water flow and transport simulations. For site characterization and monitoring of the contaminant distribution and extent, an optimal sampling methodology is presented. The sampling design is based on geostatistical methods and yields optimal estimation of the subsurface parameters and pollutant concentrations, therefore providing informed decision-making for ground water remediation and contaminant removal. The remediation plan is optimized so as to lower the contamination level to a pre-specified level by the end of the remediation period while minimizing the cost of pumping and treatment The objective function of the optimal feedback control model consists of a successive minimization of a weighted sum of squared deviations of the achieved cleanup level at each stage from the desired target level of ground water quality.