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

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

For more information on Optimization, please contact:

Kirby Biggs
Technology Integration and Information Branch

PH: 202-823-3081 | Email:


Key Optimization Components:  Conceptual Site Model

Key Optimization Components Key Optimization Components Remedy Components A project life cycle conceptual site model (CSM) is a comprehensive graphical and written summary of what is known or hypothesized about environmental contamination at a site and the relationships among key site information that are pertinent to decision-making. A CSM is a representation that evolves over the life cycle of site investigation and cleanup efforts. It provides a platform for evaluating the data gaps and related uncertainty associated with site history and operations; geology, hydrogeology and hydrology; contaminant sources, release mechanisms and fate and transport; potential receptors and exposure pathways. The development of an accurate CSM is vital to the project and site decision-making process.

A project life cycle CSM is comprised of six stages, as described below:

  1. Preliminary CSM Stage – Site representation based on existing data; conducted prior to systematic planning efforts.
  2. Baseline CSM Stage – Site representation used to gain stakeholder consensus or disagreement, identifies data gaps and uncertainties; conducted as part of the systematic planning process.
  3. Characterization CSM Stage – Continual updating of the CSM as new data or information is received during investigations; supports remedy decision making.
  4. Design CSM Stage – Targeted updating of the CSM to support remedy design.
  5. Remediation/Mitigation CSM Stage – Continual updating of the CSM during remedy implementation; and providing the basis for demonstrating the attainment of cleanup objectives.
  6. Post Remedy CSM Stage – The CSM at this stage is used to support reuse planning and placement of institutional controls if warranted.
Selected Resources

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  Title Document Number Type Date
PDF Best Practices for Data Management Technical Guide EPA 542-F-18-003 Guidance 2018
PDF Smart Scoping for Environmental Investigations Technical Guide EPA 542-G-18-004 Guidance 2018
PDF Strategic Sampling Approaches Technical Guide EPA 542-F-18-005 Guidance 2018
PDF Best Practices for Environmental Site Management: A Practical Guide for Applying Environmental Sequence Stratigraphy to Improve Conceptual Site Models EPA 600-R-17-293 Guidance 2017
PDF Brownfields Road Map Website - Project Life Cycle Conceptual Site Model EPA 542-F-11-011 Factsheet 2011
PDF Environmental Cleanup Best Management Practices: Effective Use of the Project Life Cycle Conceptual Site Model EPA 542-F-11-011 Factsheet 2011
PDF Triad Issue Paper: Using Geophysical Tools to Develop the Conceptual Site Model EPA 542-F-08-007 Technical Publication 2008
PDF Innovations in Site Characterization Case Study: The Role of a Conceptual Site Model for Expedited Site Characterization Using the Triad Approach at the Poudre River Site, Fort Collins, Colorado EPA 542-R-06-007 Case Studies 2006
PDF Characterization of Mine Leachates and the Development of a Ground-Water Monitoring Strategy for Mine Sites EPA 600-R-99-007 Technical Publication 1999
PDF The Role of Cost in the Superfund Remedy Selection Process, Quick Reference Fact Sheet EPA 540-F-96-018 1996
PDF Superfund Program Representative Sampling Guidance, Volume 1: Soil EPA 540-R-95-141 Guidance 1995
PDF Guidance for Evaluating the Technical Impracticability of the Ground-Water Restoration EPA 540-R-93-080 Guidance 1993
PDF Guidance for Conducting Remedial Investigation and Feasibility Studies Under CERCLA EPA 540-G-89-004 Guidance 1988

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