HPx

On this page, we illustrate how:

• you define the scaling factors of the hydraulic conductivity at the initial time
• you account for evolving scaling factors with time in the water flow and solute transport model

Setting the scaling factor for the hydraulic conductivity at the initial time

The initial values of the scaling factor of the hydraulic conductivity can be set in following ways:

The Soil Profile - Graphical Editor or Soil Profile - Summary pre-processing dialogue windows of the HYDRUS graphical user interface

Via the Soil Profile - Graphical Editor, use following commands:

Conditions -> Scaling Factor -> Hydraulic conductivity

Click Edit condition (see figure below)

Select nodes and set the values for selected top and bottom node

or

Select "scaling factors" from toolbar (see figure below)

Select "hydraulic conductivity"  (see figure below)

Click Edit condition (see figure below)

Select nodes and set the values for selected top and bottom node

Via the Soil Profile - Graphical Summary:

Nodal values for the scaling factor of the hydraulic conductivity at the initial time are defined in the column with heading Bxz (see figure below)

The Project Navigator 

Via Domain Properties -> SF - Hydraulic Conductivity (see figure below)

Initial calculations using calculated_values in geochemistry input

With -state initial, the script is executed once at the beginning for the transport simulations for each node. This option can be used to calculate the values of the scaling factor of the hydraulic conductivity at initial time. The script functions change_sfcond() and change_sfcond0() are used to change the value of the scaling factor of the hydraulic conductivity and the scaling factor of the hydrauilc conductivity at the initial time (to keep the initial value).

The example below illustrates how to set the values for the scaling factor for the hydraulic conductivity assuming that the it has been calculated and stored as the variable porosity.

Changing porosity and scaling factor for water content with time

To use the updated scaling factor of the hydraulic conductivity in the water flow and solute transport model, one needs to:

• calculate and update the scaling factor
• indicate that the scaling factor of the hydraulic conductivity changes during the flow and transport simulation

Calculate and update the scaling factor

After the geochemical calculations in each time step and for each node, the scaling factor needs to be updated. The scripts associated with -state update of the calculated_values data block are executed for each node after the geochemical calculations in each time step. 

Indicate evolving using updated transport properties in the flow and transport model

To indicate that a changed porosity and scaling factor of the water content has to be used, -update hp in reactive_transport is set true.

Alternatively, the option for updating hydraulic parameters (check Evolving Transport Properties; check Hydraulic Properties) can be selected in the Model options->Evolving transport properties form of the Reactive Transport Panel.

Important: The scaling factors of the hydraulic conductivity are only updated with the statements  change_sfcond(). The updated values are only used in the water flow and solute transport model with the identifier -update hp true.