A model for simulation of surface-water integrated flow and transport in two dimensions: user's guide for application to coastal wetlands

Abstract

This report provides documentation for the U.S. Geological Survey (USGS) Surface-Water Integrated Flow and Transport in Two-Dimensions (SWIFT2D) model, for application to coastal wetlands. Some of the material within this report was derived from manuals and technical notes published by the Rand Corporation to describe the original two-dimensional model, referred to as SIM2D, and its supporting simulation system, SIMSYS2D, developed in partnership with the USGS and others.

Numerical computation of hurricane effects on historic coastal hydrology in Southern Florida

“…Negative time step values indicate use of gridded data for storms. The ratio of the wind grid size to the model grid size is specified in the main surface-water input data set (Swain, 2005). Not only can this input format be used to represent a single storm, but the wind data set can be flagged at any time during the simulation and the subsequent array of wind in the gridded wind set will be used.…”

“…The primary simulator developed for representing hydrodynamic surface-water flow coupled to groundwater in a highly porous aquifer is called Flow and Transport in a Linked Overland/Aquifer Density-Dependent System (FTLOADDS) (Langevin et al 2005). FTLOADDS links the two-dimensional hydrodynamic flow and transport code SWIFT2D (Swain, 2005) with the widely used three-dimensional groundwater flow and transport code SEAWAT (Guo and Langevin, 2002). Both regimes incorporate the effects of salinity concentration on water density.…”

Measurement-derived Heat-budget Approaches for Simulating Coastal Wetland Temperature with a Hydrodynamic Model

“…An additional term (Q SOIL ) is used for the lower surface and represents soil heat flux, which is a function of conduction occurring between the water and soil; not to be confused with groundwater leakage transport of heat. Within the SWIFT2D model, which computes surface water in FTLOADDS, the heat is treated as a constituent and undergoes advection and dispersion using a two-dimensional transport equation (Swain 2005). For heat transport, the heat balance for each model cell can be expressed by:…”

“…SWIFT2D computes vertically-integrated two-dimensional forms of the equations of surface-water mass and momentum conservation and solute transport equations for salt, heat, and other constituents (Schaffranek 2004). The code was modified for application to coastal wetlands, such as the Everglades, to allow the input of spatially variable rainfall, computation of evapotranspiration, variation of frictional resistance with depth, and other necessary features (Swain et al 2004;Swain 2005). SEAWAT combines the widely used three-dimensional ground-water flow model MODFLOW with the solute-transport code MT3DMS to incorporate the effect of salinity transport (Guo and Langevin 2002).…”

Applying Downscaled Global Climate Model Data to a Hydrodynamic Surface-Water and Groundwater Model

“…The development of advanced models that couple groundwater with surface-water while representing complex hydrodynamics and salinity transport has culminated in the Flow and Transport in a Linked Overland/Aquifer Density-Dependent System (FTLOADDS) simulator [1]. In FTLOADDS, the two-dimensional hydrodynamic surface-water flow and transport simulator SWIFT2D [2] is combined with the three-dimensional groundwater flow and salinity transport simulator SEAWAT [3]. Vertical leakage and salt flux between surface water and groundwater are computed in FTLOADDS, making a complete simulation of the hydrologic system.…”