Following a public comment period and consideration of the comments received, the publication RR-649, Guidance for Documenting the Investigation of Human-made Preferential Pathways Including Utility Corridors, is now posted and available online.

RR-649, formerly titled Guidance for Investigating Utilities, focused on investigating the migration of contamination in media along the exterior of utility corridors within the surrounding utility bedding. Current research indicates that contamination and vapors may migrate within utilities as well as other preferential pathways and the updated version of RR-649 reflects this new understanding. For additional information, please see the July 2020 Issues & Trends webinar, Vapor Intrusion: New Preferential Pathways, in the Remediation and Redevelopment Program’s training library.

The guidance is intended for persons who perform and document investigation and remediation of sites with environmental contamination under Wisconsin Administrative Code (Wis. Admin. Code) chs. NR 700-799, including the Wisconsin Department of Natural Resources (DNR) staff who review such submittals.

This guidance document presents ways that utility corridors and other human-made preferential pathways can influence contaminant migration, and ways to assess and potentially sample these pathways to meet the requirements of Wis. Admin. Code § NR 716.11(5)(a). Vapor migration through human-made preferential pathways and utility conduits is of particular importance.

Additional documents and guidance from the Remediation and Redevelopment Program may be found using the search tools available on the publications and forms webpage.

Questions regarding this document may be submitted to Jim Walden at JamesE.Walden@wisconsin.gov.