A management model to control contaminant loading mass and pumping rates for sustainable roundwater use in Agricultural Region

摘要

In this study, a management model is developed to achieve sufficient groundwater supply and quality conservation for sustainable groundwater use in the agricultural regions. The model calculates the on-ground contaminant loading mass by integrating an analytical model for 1D solute transport in unsaturated zone and a 3D groundwater flow and solute transport model. The outputs of the 1D unsaturated transport model, contaminant concentrations leached on watertable, work as contaminant sources in the 3D solute reactive transport model in saturated zone. This integrated simulation model is linked to genetic algorithm that searches the global optimum for the groundwater management design. The management design involves obtaining the optimal pumping rates that are able not only to supply sufficient amount of the groundwater but also to prevent excessive drawdown and contamination. It also includes controlling the contaminant loading on the agricultural non-point sources by suggesting the allowable contaminant loading mass. For this multi-objective groundwater management, the objective function to maximize both pumping rates and allowable contaminant loading mass and the constraints for drawdown and concentration are assigned in the optimization model. The proposed groundwater management methodology can be applicable and efficient to provide the groundwater management options in the agricultural regions.