U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

FRTR Presents...Synthesizing Evolving Conceptual Site Models (CSMs) with Applicable Remediation Technologies

Sponsored by: Federal Remediation Technologies Roundtable (FRTR)

Archived: Wednesday, April 1, 2020
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This webinar features presenters and material from the November 2019 FRTR Meeting held in Reston, VA. The session will include two presentations:

Developing Conceptual Site Models of Contaminated Fractured Rocks to Support In-Situ Remediation (Presented by USGS)
Conceptual site models (CSMs) were developed to support in-situ remediation of fractured sedimentary rocks contaminated with trichloroethene (TCE) in two areas at the former Naval Air Warfare Center (NAWC) site near Trenton NJ. The understanding of heterogeneity and groundwater flow represented in these CSMs is critical to designing remediation strategies that involve spreading injected amendments to contaminant locations. In one area at NAWC, hydraulic testing, tracer testing, and flow and transport modeling were conducted to develop a CSM for designing in-situ bioremediation of TCE, involving injection of emulsified vegetable oil and bacteria. The CSM showed that injection will spread amendments widely over a zone of lower-permeability fractures, with long residence times expected because of small velocities after injection and sorption of the oil onto solids. However, amendments transported out of this zone will be diluted by groundwater flux from other directions, limiting bioremediation effectiveness downgradient. In another area of the site, hydraulic tomography (HT) was conducted to develop a high-resolution hydrogeologic CSM that depicts the extreme heterogeneity of hydraulic properties. This CSM includes an estimate of the most-hydraulically-active fracture network, which is a key component of designing in-situ remediation because amendments are spread along this network during injection. Results of these studies emphasize that for in-situ remediation of heterogeneous flow systems such as fractured rocks, the extent of injected amendments cannot be conceptualized using simple homogeneous models. Instead, it is important to develop CSMs that use characterization data and modeling to represent the heterogeneous features and simulate the spatially variable groundwater fluxes that strongly control in-situ remediation effectiveness.

Using Remedy Implementation Information to Guide Remedy Optimization (Presented by PNNL, DOE, & EPA)
During groundwater remedy implementation, data and information are collected about remedy performance and the site contaminant and hydrogeology conditions. This information can be used to refine the conceptual site model and evaluate progress toward remedial action objectives. Consistent with recent guidance for adaptive site management, it is important to consider this information with respect to remedy optimization opportunities. Groundwater remediation of carbon tetrachloride at the Department of Energy Hanford Site has followed this approach and is currently conducting an optimization study using EPA's guidance on remediation optimization. The optimization study will evaluate changes to the treatment configuration and provide information to support future decisions to improve remedy protectiveness, effectiveness, and cost efficiency, and to facilitate progress toward completion of site work.

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A photograph of Claire TiedemanClaire Tiedeman, U.S. Geological Survey ( or 650-439-2583)
Claire Tiedeman has been a research hydrologist with the USGS since 1992. Her research is focused on developing and applying methods for characterizing and modeling groundwater flow and chemical transport in fractured rocks. This work has included field studies in crystalline rocks of New Hampshire and in sedimentary rocks of New Jersey at the former Naval Air Warfare Center (NAWC) site. She was co-coordinator of USGS research on contaminant fate, transport, and remediation at the NAWC site from 2005-2018. Claire's research has also addressed calibration and uncertainty analysis for models of complex groundwater flow systems, and she co-authored the textbook Effective Groundwater Model Calibration: With Analysis of Data, Sensitivities, Predictions, and Uncertainty (Hill and Tiedeman, 2007, John Wiley and Sons).

A photograph of Mike TruexMike Truex, Pacific Northwest National Laboratory ( or 509-371-7072)
Michael Truex has 28 years of experience at Pacific Northwest National Laboratory in environmental remediation research and field applications. His experience includes work at Department of Energy, Department of Defense, and private remediation sites. Mike has authored technical guidance documents on remediation exit strategies, Monitored Natural Attenuation, vadose zone contaminant transport, and development of conceptual site models. Mike led chapter development and serves as a trainer for the ITRC 'Remediation Management of Complex Sites' document. He is also the chair for developing the International Atomic Energy Agency document entitled 'Determination of Environmental Remediation End States'.

A photograph of Emy LaijaEmy Laija, EPA Federal Facilities Restoration and Reuse Office ( or 202-845-3198)
Emy Laija is an Environmental Scientist who works on Superfund cleanups of hazardous waste sites through the EPA Federal Facility Restoration and Reuse Office (FFRRO) in Washington, DC. Her position includes implementing national policy, promoting consistency in cleanups, developing training, and developing relationships with other federal agencies and stakeholders. Before working in FFRRO, Emerald worked as a Remedial Project Manager for 8 years in EPA's Hanford Project Office in Richland, WA and continues to serve as a Hanford subject matter expert. She earned a Master's Degree focused in Environmental Studies from University of Nevada-Las Vegas and a Bachelor's Degree from the University of Texas at El Paso.

A photograph of Kate AmrheinKate Amrhein, U.S. Department of Energy Richland Operations Office (
Kate Amrhein joined the Richland Operations Office (RL) in 2015 as a member of the Soil and Groundwater Division. She is a subject matter expert for the 200 West Pump and Treat, as well as for the 200-UP-1 and 200-ZP-1 Groundwater Operable Units. Prior to working at RL, Kate began her federal career at the Office of River Protection in 2014 as part of the Pathways Recent Graduate Program. She was a member of the One System Division, part of the Hanford Tank Waste Treatment and Immobilization Plant Start-Up, Commissioning and Integration group, working with flowchart and operational research modeling. Kate holds a Master's Degree in Geology from Kansas State University and a Bachelor's Degree in Geology from Grand Valley State University in Michigan.


A photograph of Jean BalentJean Balent, U.S. EPA Technology Innovation and Field Services Division ( or 202-566-0832)
Ms Balent is on the staff of the EPA's Technology Innovation and Field Services Division where she has worked to collect and disseminate hazardous waste remediation and characterization information since 2003. Ms Balent manages the Clean Up Information Network website and actively supports online communication and collaboration resources available to EPA. She formerly worked with the US Army Corps of Engineers Environmental Engineering Division in the Buffalo District. Ms Balent was also a member of the SUNY-Buffalo Groundwater Research Group where she constructed and tested large scale models of groundwater flow. Ms Balent has also conducted research relating to the Great Lakes, environmental remediation, and brownfields re-development. She holds a Bachelor's degree in environmental engineering from SUNY-Buffalo and a Master's degree in Information Technology from AIU.

A photograph of Cindy FrickleCindy Frickle, U.S. EPA Office of Superfund Remediation and Technology Innovation ( or 202-566-0927)
Cindy Frickle is a physical scientist with EPA's Superfund program where she reviews and propagates technical information to site cleanup professionals through Clu-In, EPA forums, and interagency channels. Prior to joining EPA, she spent time characterizing contaminated sites, coring sediments, studying microbes, and teaching. She completed her Biogeology MS and Geology BS in the University of Minnesota's School of Earth Sciences.

Webinar Slides and References:

  • These materials will be available by Wednesday, April 1, 2020

Webinar Slides and References:

  • These materials will be available by Wednesday, April 1, 2020

Additional Resources:

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If you have a suggested topic or idea for a future CLU-IN internet seminar, please contact:

Jean Balent
Technology Integration and Information Branch

PH: 202-566-0832 | Email:
Michael Adam
Technology Integration and Information Branch

PH: 202-566-0875 | Email: