Calculating Volumes and Masses

Add the volumetrics module to your network so that it looks like this:

The volumetrics module should be connected directly to Krig_3D. If you connected it to Explode_and_Scale, the volumes and masses would be exaggerated by the scale factor in Explode_and_Scale. You can use the explode and scale ports in volumetrics to compensate for this, but it is simpler if it is connected to the original, unscaled, unexploded field.

There are times when you might want to insert other Subsetting or Processing modules in between Krig_3D and volumetrics. Examples are plume_volume or field_math. As an example, the plume_volume (lower case) module could be used to subset the domain to include only those regions above or below a particular elevation or depth.

After connecting volumetrics, we must change one of Krig_3D's parameters to be sure we don't calculate an inappropriate estimation of chemical mass. Go to Krig_3D's Data Processing window and change the Post-Clip max parameter to 1.000000e+009 (1 billion), thus insuring we aren't clamping the extreme maximum values in our kriged output. Now re-run Krig_3D by clicking AcceptAll Current Values in the Krig_3D window.

Now, open the volumetrics window. Change the Iso Level to 1 mg/kg and the Volume Units to Cubic Meters. This causes volumetrics to calculate the volume and chemical mass for the regions of the model above 1 mg/kg.

This will also update the Subsetting Level in plume_shell

The Viewer should show:

The volumetrics window should now look like this:

Since our data files have their units specified correctly, volumetrics automatically determined the appropriate values for Type of Calculation (Soil), Data Processed (Log), CoordinateUnits (feet), and units (mg/kg). Setting up the input data with this information can help prevent mistakes from occuring in the post-processing.

You can adjust the subsetting level (which should be in original units: not log10 values), the dollars per volume or mass unit, the input units or output units. You can also select specific geologic layers (versus calculating the entire domain). This is especially useful if the porosity of individual layers is highly variable and an accurate estimate of ground water chemical mass is required. For detailed information on volumetrics parameters refer to the Module Library help section.