4- Site Characterization

Site characterization is a set of site-specific activities designed to identify and understand contaminants and contaminant sources at a site.  

All sites in the VRP require site characterization, which helps ensure:   

  • Adequate and appropriate information is available to support selection and implementation of remedial actions.
  • The level of detail is commensurate with the complexity of the site and/or release in question.

Performance Criteria and Information Gathering

Site characterization involves undertaking the following activities to support identification of a site-specific remedy: 

  • Data and information gathering
  • Development of a Site Conceptual Model
  • Preparation of a Site Characterization Work Plan

DEQ will evaluate the adequacy of site characterization using performance criteria and good engineering and geological practices. 

Site characterization performance criteria are drawn from the requirements for preliminary remediation agreements (see Fact Sheet 21) and the VRP cleanup standards (see Fact Sheets 12 and 13).

Click here to view a table of performance criteria.

Site Conceptual Model

A site conceptual model is a description of the surface and subsurface of a site and the site environmental setting. This description includes the following: 

  • Containment sources
  • Release mechanisms
  • Migration routes
  • Potential human and ecological receptors
  • Exposure pathways

A Volunteer should create the site conceptual model early in the process using known information about the site and then update it as site characterization moves forward.

The Site Conceptual Model organizes site information in a way that highlights data gaps and focuses site characterization activities.

Site Characterization Work Plans

General expectations for site characterization are negotiated in a preliminary remediation agreement. From there, specific activities are developed in a site-specific characterization work plan that is submitted by the Volunteer for DEQ review and approval.  

Site characterization work plans describe the site conceptual model and the specific activities required to complete site characterization, which include:

  • Data quality objectives, such as the specific purpose of any sampling proposed and how the data generated will be used
  • A Volunteer’s plan to ensure data quality
  • Sampling and analytical methods
  • Plans to protect workers and the public from hazards through a site-specific health safety plan
  • A Volunteer’s report to document site characterization activities

For more detailed information, please refer to Fact Sheet 8.