MODFLOW wetland module which relates interactions with aquifers and sloughs

Natural and anthropogenic processes have altered wetland habitats. The simulation of surface water movement and its interaction with groundwater and slough channels as it relates to wetlands is very important for many projects. Currently, most groundwater flow models incorporate the wetland system as general head boundary nodes. The purpose of this research was to develop a computer package for the widely used MODFLOW code to simulate three-dimensional wetland flow hydroperiods interacting with aquifers and slough channels. The groundwater flow model was used to reproduce surface water flow process through wetlands, estimating new flow rates and values using a Manning type of equation. This package represents flow routing, the export/import of water, and the evapotranspiration from wetlands during different hydroperiods. The verification procedure for the numerical solution was based on a test-case that was solved using a two-dimensional surface water model. This test-case example is a transient solution to the diffusion equation starting with initial conditions depicted by a sinusoidal water surface profile and a flat bottom.