A MODFLOW Package to Linearize Stream Depletion Analysis

Abstract:

The conventional numerical method is computationally intensive and prone to numerical noises for stream depletion analysis using MODFLOW. In this study, a new MODFLOW package has been developed to improve the computational efficiency and reduce the noises for each simulation of stream depletion analysis. Under the assumption of unchanged flow coefficients between the baseline and scenario runs, the nonlinear groundwater flow system is linearized for solving the flow equations. The new package has been successfully applied to a regional groundwater model in Nebraska. The results shows the numerical noises, commonly identified in conventional approach, have been significantly reduced and a twentyfold speedup achieved. The results suggest this package can be adapted to be a component of optimization tools for water management scenario analyses especially when a large number of scenario model runs are involved.