TVDLF Method to Simulate Two-Dimensional Flow through Large Hydrologic Systems with Wetlands and Hillslopes

Abstract

This paper presents a physical process-based integrated hydrologic model for multiyear simulations of surface and subsurface flow in large regional hydrologic systems with hillslopes, wetlands, natural, agricultural, and urban landscapes. This paper shows the conceptualization of hydrologic processes, the formulation of the governing hyperbolic-parabolic partial differential equations (PDEs), and the development of a numerical method. The model uses the Total Variation Diminishing Lax Friedrichs (TVDLF) method to solve governing equations for regional-scale processes. The method provides an extension to the Regional Simulation Model (RSM) developed by the US Army Corps of Engineers and the South Florida Water Management District using a finite volume approach and a diffusion wave method to solve one- (1D) and two-dimensional (2D) surface and subsurface flows simultaneously using external equation solvers. The model’s object-oriented software design approach enables the complete integration of all 1D and 2D components into the solver. The accuracy of the numerical solutions is tested using steady-state and transient-state tests. The model is applied to the Boggy Creek watershed in the Kissimmee River basin in Florida and the Metro Colombo catchment in Sri Lanka.