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Characterizing a Complex TCE Groundwater Plume, Eliminating Suspected Source Areas, and Reducing Investigation Costs for a RCRA RFI at Shaw AFB, SC

Triad Elements Used

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Table of Contents

  1. Site Information
  2. Project Information
  3. Triad Approach Information
  4. Supporting Information

1. Site Information

Site Name Shaw Air Force Base
Location Sumter, SC
Site Type  DoD Facility
Project Lead Type  U.S. Air Force Lead
Reuse Objective Identified  No

Contaminant(s) of Concern 

Contaminated Media 

2. Project Information

Project Objectives/Decisions 

In line with the U.S. Air Force (USAF) primary strategy for all Installation Restoration Projects (IRP) site processing - Remedy in Place (RIP) by 2012, the strategic objectives for this project were to:

Remedial Phase

Site Investigation (Includes RI/FS or Similar Detailed Investigation Work)

Triad Project Benefits 

During the course of this investigation using the Triad approach, trust was built among stakeholders through collaboration; the Field Sampling Plan was approved with out revision; field sampling showed that six previously suspected source areas were not sources; the location of the actual source was identified and characterized; and plumes were completely characterized during a single 6-month high-resolution site characterization (HRSC) field effort. This provided about $80K in direct cost reductions and an estimated $450K in cost avoidance.

Cost and Time Savings 

Overall, using the Triad Approach resulted in about $80K in direct cost reductions and an estimated $450 K in cost avoidance. Time savings was estimated to be approximately two years.

3. Triad Approach Information

Systematic Project Planning 

A systematic planning session was held in February 2006 at Shaw AFB. Stakeholders included Shaw Environmental & Infrastructure, Shaw Air Force Base, USAF Air Combat Command (ACC), U.S. Army Corps of Engineers (USACE) Omaha, and South Carolina Department of Health and Environmental Control (DEHC).

The most difficult issue in development of the conceptual site model (CSM) was identifying the release area and plume migration pathways. Six potential release areas were investigated and eliminated. Using an HRSC approach of sampling transects, the actual release area was identified in an area where a water table aquifer recharges a deeper drinking water aquifer. The groundwater flows in opposite directions in these two aquifers, so the plumes extend in opposite directions. The CSM was presented in a Triad Team conference call prior to developing the work strategies. The CSM was a dynamic concept, and changes to the CSM were based on findings of the real-time measurements and agreed to during Triad conference calls during the field investigation. The six initial suspected release areas were eliminated from the CSM, and an agreement for no further investigation was reached during the field investigation during a Triad Team conference call.

Dynamic Work Strategies 

Based on the initial CSM and agreed upon objectives, the details of the adaptive Field Sampling Plan were developed using a high-density data set of vertical groundwater samples and an on-site laboratory or a fixed-base lab using rapid turnaround to characterize the site in 3-D. Because the Triad Approach involved all stakeholders in work plan development, the work plan was approved without the need for revision.

Real-Time Measurement Technologies 

The on-site laboratory produced preliminary data in less than one hour and high-quality data in 24-36 hours for the initial phase of the vertical groundwater profiling. The fixed-base laboratory provided rapid turnaround time (TAT) data in 48 hours during the second phase of the profiling.

Daily electronic data delivery (EDD) allowed immediate incorporation into a database, and an interactive Web-based map allowed downloading and review of the data by all stakeholders. High-resolution vertical groundwater profiling and on-site or rapid TAT sample analysis established contaminant distribution and concentrations in two aquifers over a 1.5-square-mile area. Using the project Web site, the project database was available to all project stakeholders using an interactive map. The database was updated as EDDs were received. A 3-D animated CSM was also available on the project Web site, and updated weekly, allowing stakeholders timely review. Weekly Triad Team conference calls that were held to review the latest CSM update, make decisions on where to sample next, and resolve other technical issues allowed the plumes to be effectively tracked, and agreements reached between all stakeholders regarding when characterization was complete.

Technology Category(s) for Sampling and Analysis 

4. Supporting Information

Dates of Operation - Field Work


Electronic Documentation of Supporting/Related Information

Link Characterizing a Complex TCE Groundwater Plume, Eliminating Suspected Source Areas, and Reducing Investigation Costs for a RCRA RFI at Shaw AFB, SC abstract for presentation by Jonathan Shireman, to the Triad Conference, Amherst, MA, June 2008.

Point(s) of Contact 

Jonathan Shireman
Shaw Environmental and Infrastructure, Inc.
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Juvenal Salomon
Shaw Environmental and Infrastructure, Inc.
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Jody Edwards, PG
Stone Environmental
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Last Update:  02/13/2009

To update this profile, contact Cheryl T. Johnson at or (703) 603-9045.