Friday, December 9, 2022

TS-CHEM - The Swiss-Army Knife of Solute Transport Modeling

Understanding Plume Movement at a Site

Environmental professionals are often tasked with investigating contaminated sites to understand the nature and extent of contamination in groundwater, and select an appropriate remedy that will effectively limit migration of impacted groundwater, treat it, and prevent groundwater plumes from reaching sensitive receptors.  To do this, a sound conceptual site model (CSM) is necessary, which requires not only collection of adequate site data (including groundwater sampling data, water level elevation data, and information on site hydrogeologic conditions) and application of professional judgement, but also the use of data analysis tools and techniques that allow for a better understanding of the fate and transport of contaminants in groundwater.

Plume Modeling Tools

Although there are a number of analytical solute transport modeling tools that are freely available (such as the Pennsylvania Department of Environmental Protection’s Quick Domenico Model, and the United States Environmental Protection Agency’s BIOCHLOR model), these tools are relatively simple, and while they serve as great screening level tools, they are typically limited in how they represent site source conditions (e.g., as a constant concentration “patch” source) and in how they present results (often only a simple concentration versus distance curve with no plume contour plot).  

Better Representation of the Contaminant Source

Simplified source condition models may be adequate for some site analyses  (e.g. for conservative screening analyses) but, in reality, sources of groundwater contamination are usually more complex, and may need to be represented in a different way.  Does this mean that as an environmental professional, you have to plan on additional budget for the development of a more sophisticated 3D numerical fate and transport model, or forgo any modeling analyses altogether due to budget and time constraints? The answer is no.  

As environmental professionals ourselves who routinely conduct solute transport modeling analyses as part of our work, we wanted to develop a tool that included the many analytical solutions that have been developed over the last several decades – essentially, a “Swiss Army Knife” of solute transport modeling.  So, we developed TS-CHEM to include a library of More than 30  Analytical Solutions, each with different capabilities, including how they represent contaminant sources.  The various solutions within the TS-CHEM library are capable of representing sources as points, lines, volumes, and patches (including rectangular and circular geometries).  Additionally, source concentrations can be continuous, constant, decaying, and/or transient.  This provides a great deal of flexibility in allowing for the selection of source configurations that best represent site conditions. 

Figure 1 - TS-CHEM Source Geometry Capabilities

Better Presentation of Analysis Results

In addition to having only limited capabilities with regard to source representation, many freely available solute transport modeling tools also lack the ability to analyze and interpret modeling results – often only showing simple plots of concentrations vs. time/distance.  As environmental professionals, there are typically other information needs that arise when developing our CSMs and planning remedies. For example, what volume of water is impacted?  What is the estimated contaminated mass within the plume?  What is the mass flux through a segment of the plume?  Based on our experience in performing solute transport modeling analyses to assist with CSM development and remedy planning (and having these kinds of questions come up), we built in a whole suite of analysis tools into TS-CHEM, including tools that allow for the estimation of:

Plume area
Plume volume (including total aquifer volume, and water within aquifer materials)
Plume mass
Average plume concentration
Plume mass flux

Figure 2 - TS-CHEM Plume Mass Calculator Analysis Tool

These TS-CHEM analysis tools allow environmental professionals to quickly and easily obtain key information about groundwater plume characteristics, without having to export data and analyze it in another software program (or programs) – another reason why TS-CHEM is the “Swiss Army Knife” of solute transport modeling!

To learn more about TS-CHEM, or to download a FREE DEMO VERSION of the software, visit the TS-CHEM Website today!

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