Management model of a groundwater system with a transient pollutant source

A management model is presented for determining the maximum concentration of a transient pollutant source such that space-dependent groundwater quality requirements are met. The method is illustrated using a one-dimensional groundwater system with a single pollutant source at an adjacent stream. The chloride concentration of the source is to be managed to meet variable groundwater quality constraints. Management of the pollutant source is demonstrated for a single-period as well as for repeated-period pollutant discharges. The Crank-Nicolson numerical approximation of the convective-dispersive equation is used in the management model. The pollutant source concentration is treated as a parameter in the resulting system of linear equations. Taking advantage of the block structure of the matrix, the concentrations throughout the system are defined and manipulated as functions of this parameter for each time step. The parameter is maximized by comparison of groundwater quality limits with the groundwater solute concentrations at the corresponding nodes. The minimum value of the parameter over the entire time frame is the maximum concentration allowable in the source water over the management period or periods.