The Horizontal Flow Barrier (HFB) package simulates thin, vertical low-permeability geologic features that impede the horizontal flow of groundwater. The pane for this package is on the MODFLOW Packages and Programs dialog box under Flow Packages. These geologic features are approximated as a series of horizontal-flow barriers conceptually situated on the boundaries between pairs of adjacent cells in the finite-difference grid. The key assumption underlying the HFB Package is that the width of the barrier is negligibly small in comparison with the horizontal dimensions of the cells in the grid. Barrier width is not explicitly considered in the Package, but is included implicitly in a hydraulic characteristic defined as either (1) barrier transmissivity divided by barrier width, if the barrier is in a constant-transmissivity layer, or (2) barrier hydraulic conductivity divided by barrier width, if the barrier is in a variable-transmissivity layer. Furthermore, the barrier is assumed to have zero storage capacity. Its sole function is to lower the horizontal branch conductance between the two cells that it separates.
In ModelMuse, the user specifies the hydraulic conductivity and thickness of the barrier. ModelMuse calculates the hydraulic characteristic of the barrier from these inputs.
Faults and slurry walls are both features that might be simulated with the Horizontal Flow Barrier package.
Parameters used in the Horizontal Flow Barrier package are defined in this pane. The only allowed parameter type is HFB, which defines values of the hydraulic characteristic of the barrier.
Each parameter must have a unique Name. Only ASCII characters are allowed in parameter names.
The Value of the parameter is used to determine the input to MODFLOW.
Parameters can also be edited in the Manage Parameters dialog box.
