volumetrics

The volumetrics module is used to calculate the volumes and masses of soil, and chemicals in soils and ground water, within a user specified constant_shell (surface of constant concentration), and set of geologic layers. The user inputs the units for the nodal properties, model coordinates, and the type of processing that has been applied to the nodal data values, specifies the subsetting level and soil and chemical properties to be used in the calculation, and the module performs an integration of both the soil volumes and chemical masses that are within the specified constant_shell. The results of the integration are displayed in the EVS Information Window, and in the module output window.

The volumetrics module computes the volume and mass of everything passed to it. To compute the volume/mass of a plume, you must first use a module like plume or intersection to subset your model.

NOTE: Do not use plume_shell or intersection_shell upstream of volumetrics since their output is a hollow shell without any volume.

The volumetrics module computes volumes and masses of analytes using the following method:

• Each cell within the selected geologic units is analyzed

• The mass of analyte within the cell is integrated based on concentrations at all nodes (and computed cell division points)

• The volumes and masses of all cells are summed

• Centers of mass and eigenvectors are computed

• For soil calculations the mass of analyte is directly computed from the computed mass of soil (e.g. mg/kg).  This is affected by the soil density parameter (all densities should be entered in gm/cc).

• For groundwater calculations, the mass of analyte (Chemical Mass) is computed by first determining the volume of water in each cell.  This uses the porosity parameter and each individual cell's volume.  From the cell's water volume, the mass of analyte is directly computed (e.g. mg/liter).  

• The volume of analyte (Chemical Volume) is computed from the Chemical Mass using the "Chem Density" parameter (all densities should be entered in gm/cc).

Module Input Ports

• Z Scale [Number] Accepts Z Scale (vertical exaggeration).
• Explode [Number] Accepts the Explode distance from other modules
• Input Field [Field] Accepts a field with data.
• String for Output [String]
• Input Subsetting Level [Number] Accepts the subsetting level

Module Output Ports

• Output Subsetting Level [Number] Outputs the subsetting level
• Soil Volume Level [Number] Outputs the computed soil volume
• Soil Mass Level [Number] Outputs the computed soil mass
• Chemical Volume Level [Number] Outputs the computed chemical volume
• Chemical Mass Level [Number] Outputs the computed chemical mass
• Nodal Data Component [String] The name of the analyte
• Volume Units [String] The units of the volume calculations (e.g. m3)
• Result Value [Number] The final output
• Output Second Moment Object [Renderable]: Outputs to the viewer

You can use the Geologic Layers selection list which allows you to choose the cell sets (geologic layers) that you want to perform computations on.  

The Soil Density and Porosity inputs allow the user to input the properties of the soil matrix in which the chemicals reside. Note that if the mass of chemicals in a combined soil and ground water plume are to be estimated, one of the geologic layers should be set up to have a boundary within it that corresponds to the water table position. In essence, this will create two layers out of one geologic unit that can be used to separate the soil domain from the ground water domain. The user can then choose the appropriate Nodal Data Units for each layer in the two domains, and obtain volumetrics estimates by summing the results in individual layers. There are several other alternative methods for completed volumetrics estimates in continuous soil and ground water plumes, which involve either setting up separate soil and ground water models, or using the Field Math module to remove and include specified areas of the domains.

The Chemical Density input allows the user to input the density of the chemical constituent for which mass estimates are being completed. Note that this value is used to calculate the volume of chemical in the specified constant_shell, as the mass units are calculated directly from the nodal data.

Volume Dollars is used along with the total volume of the chemical to indicate the cost of the removal of the chemical.

Mass Dollars is used, along with the total chemical mass, to determine the value of the chemical mass.

Volume Units is used to select which units the volume should be calculated in. For the Specified Unit Ratio the units to convert to are liters. For example if your units were Cubic Meters the ratio would be 1000.

Mass Units is used to select which units the mass should be calculated in. For the Specified Unit Ratio the units to convert to are Kilograms.

The Output Results File toggle causes volumetrics to write a file to the ctech folder (volumetrics_results.txt) that contains all volumetrics information in a format suitable for input to programs like Excel (tab delimited .txt file). This file is written to in an append mode. It will grow in size as you use volumetrics. You should delete or move the file when you're done with it.

The Run Automatically toggle, when selected, causes the module to run as soon as any of the input parameters have changed. When not selected the accept button must be pushed for the module to run.

There is an advanced window that can be opened by checking the Advanced Output Options toggle.

The advance panel provides many capabilities including Spatial Moment Analysis.

• Spatial Moment Analysis involves computing the zeroth, first, and second moments of a plume to provide measures of the mass, location of the center of mass, and spread of the plume.

• The zeroth moment is a mass estimate for each sample event and COC. The estimated mass is used to evaluate the change in total mass of the plume over time.

• The first moment estimates the center of mass of the plume (as coordinates Xc , Yc, & Zc).

• The second moment indicates the spread of the contaminant about the center of mass (sxx,syy andszz), or the distance of contamination from the center of mass. This is somewhat analogous to the standard deviation of the plume along three orthogonal axes represented as an ellipsoid created using the eigenvalues as the ellipsoid major and minor axes, and the eigenvectors to orient the ellipsoid. The orientation of the ellipsoid is aligned with the primary axis of the plume (not the coordinate axes).

• The Second Moment ellipsoid represents the spread of the plume in the x, y and z directions. Freyberg (1986) describes the second moment about the center of mass as the spatial covariance tensor.

• The components of the covariance tensor are indicative of the spreading of the contaminant plume about the center of mass. The values of sxx,syy andszz represent the axes of the covariance ellipsoid. The volumetrics module provides a scaling parameter that allows you to view the ellipsoid corresponding to the one-sigma (default) or higher sigma (higher confidence) representation of the contaminant spread.

The Water Density type in window allows the user to specify the density of water. The default of 0.9999720 g/mL (gm/cc) is the Density of Water at 4.5 degrees Celsius.

The Output Filetype radio list is used to select the format of the output file. The default is a tab spaced single line output, the second choice will format the output the same as the display window, and the third option will format the output separated by tabs on multiple lines. Changing these options will not cause the module to run, you must hit accept or change an input value for the module to run.

Overwrite causes the output file to be overwritten instead of appended to. This toggle will only be selected for one run and then will unselect itself and begin appending again, unless it is rechecked. Selecting this toggle will not cause the module to run, you must hit accept or change an input value for the module to run.

The Date type in allows you to set the date, which is output only in the Tabbed Multi-Line file.

Connecting the Red Output Port of volumetrics to the viewer will display the Second Moment Ellipsoid and the Eigenvectors (if turned on).

The three toggles:

1. Display Mass Along Major Eigen Vector
2. Display Mass Along Minor Eigen Vector
3. Display Mass Along Interm(ediate) Eigen Vector

allow you turn on and off the lines lying along the Major, Minor, and Intermediate Eigenvectors. These vectors represent the second moment of mass, and by default have chemical data mapped to them. These lines are of the same orientation as the second moment ellipse but they stretch only to the extents of the model. To output these lines the Export Results button must be pushed.

The Segments In Lines type in allows you to control the number of segments making up each line, the larger the number of segments the closer the node data along the line will match the node data of the model.

The Color Lines by Axis toggle strips the node data from the lines leaving them colored by the axis the represent.

EllipsoidResolution is an integer value determines the number of faces used to approximate the analytically smooth ellipsoid. The higher the resolution the smoother the ellipsoid.

EllipsoidScale is a scaling factor for the second moment ellipsoid. A value of 1.0 (default) is analogous to one-sigma (67%) statistical confidence. Higher values would provide an indication of the size of the eigenvalues with a higher statistical confidence.