High Resolution Site Characterization to Increase Corrective Action Efficiency.pdf

Kathryn Farris, Arcadis US, Inc.
Margaret Gentile, Arcadis US, Inc.
Geoff Gay, Arcadis US, Inc.

Description

High Resolution Site Characterization to Increase Corrective Action Efficiency Authors Ms. Kathryn Farris - United States - Arcadis US, Inc. Dr. Margaret Gentile - United States - Arcadis US, Inc. Mr. Geoff Gay - United States - Arcadis US, Inc. Abstract Many Coal Combustion Residuals (CCR) sites regulated under the 2015 CCR Rule are entering the stage of implementation of corrective actions for Appendix IV constituents. Often, the data describing Appendix IV impacts above Groundwater Protection Standards are limited to monitoring well data from the compliance monitoring well networks established for CCR rule assessment and detection monitoring. Traditional monitoring well networks are designed to provide reproducible data for compliance monitoring, but may not be the best option for determining plume thickness and extent and mass flux, for purposes of corrective action design. Groundwater plumes often migrate in distinct pathways that are a function of the aquifer architecture and plume strength, with most of the groundwater plume mass moving through a small portion of the aquifer at the majority of sites. High-resolution site characterization (HRSC) allows for mapping of the mass flux of the plume, revealing detail that may be obscured by traditional monitoring wells. This characterization allows corrective action design to focus on treating the areas that will yield the greatest results, reducing capital and operations and maintenance costs. This paper will present a case study where HRSC was implemented to map the mass flux of arsenic in groundwater along a 1,300 foot boundary of a former ash pond. The HRSC was implemented using an adaptive approach to collect data in real-time along the boundary. Continuous vertical profiles of aquifer permeability measured at 40 locations with a hydraulic profiling tool deployed with direct push tooling. Arsenic distribution and geochemical conditions were characterized by vertical aquifer profiling at eight locations. Arsenic impacts were mapped to a small, approximately 100-foot long portion of the 1,300 foot boundary, reducing the potential scope of the selected remedy of in situ injections by over 90%.

 
May 15th, 9:00 AM May 15th, 9:30 AM

High Resolution Site Characterization to Increase Corrective Action Efficiency.pdf

Grand Rapids, Michigan

High Resolution Site Characterization to Increase Corrective Action Efficiency Authors Ms. Kathryn Farris - United States - Arcadis US, Inc. Dr. Margaret Gentile - United States - Arcadis US, Inc. Mr. Geoff Gay - United States - Arcadis US, Inc. Abstract Many Coal Combustion Residuals (CCR) sites regulated under the 2015 CCR Rule are entering the stage of implementation of corrective actions for Appendix IV constituents. Often, the data describing Appendix IV impacts above Groundwater Protection Standards are limited to monitoring well data from the compliance monitoring well networks established for CCR rule assessment and detection monitoring. Traditional monitoring well networks are designed to provide reproducible data for compliance monitoring, but may not be the best option for determining plume thickness and extent and mass flux, for purposes of corrective action design. Groundwater plumes often migrate in distinct pathways that are a function of the aquifer architecture and plume strength, with most of the groundwater plume mass moving through a small portion of the aquifer at the majority of sites. High-resolution site characterization (HRSC) allows for mapping of the mass flux of the plume, revealing detail that may be obscured by traditional monitoring wells. This characterization allows corrective action design to focus on treating the areas that will yield the greatest results, reducing capital and operations and maintenance costs. This paper will present a case study where HRSC was implemented to map the mass flux of arsenic in groundwater along a 1,300 foot boundary of a former ash pond. The HRSC was implemented using an adaptive approach to collect data in real-time along the boundary. Continuous vertical profiles of aquifer permeability measured at 40 locations with a hydraulic profiling tool deployed with direct push tooling. Arsenic distribution and geochemical conditions were characterized by vertical aquifer profiling at eight locations. Arsenic impacts were mapped to a small, approximately 100-foot long portion of the 1,300 foot boundary, reducing the potential scope of the selected remedy of in situ injections by over 90%.