A SIMULTANEOUS SOLUTION APPROACH FOR COUPLED SURFACE AND
SUBSURFACE FLOW MODELING
O. Gunduz and M. M. Aral
Multimedia Environmental Simulations Laboratory
School of Civil and Environmental Engineering
Georgia Institute of Technology
Abstract
Coupled hydrologic modeling of surface and subsurface systems has gained a lot of popularity in the last two decades. Channel flow and groundwater flow models are coupled to obtain a better understanding of these hydrologic pathways in a watershed. In general, this coupling process is done in an iterative fashion until sufficient convergence is achieved for common parameters linking these different domains. In this study, we propose a new solution methodology based on the simultaneous solution of channel and groundwater flow. The method is based on the idea of solving a single global matrix at once rather than solving separate matrices for each flow domain and iteratively improving the solution. This new solution technique is tested by coupling a one-dimensional stream flow model that uses the complete form of the St. Venant equation with a two-dimensional vertically-averaged groundwater flow model. The proposed simultaneous solution approach provides a more efficient solution for this coupled flow problem and is superior to the approximate solution obtained through an iterative approach.