Electromagnetic Borehole Flowmeter Surveys at Selected In Situ Redox Manipulation Barrier Wells, Zero-Valent Iron Site, Hanford, Washington

摘要

One of the primary causes of the premature breakdown in reductive capacity of the aquifer at the In Situ Redox Manipulation (ISRM) barrier site is physical heterogeneity within the aquifer (DOE 2004). Preferential pathways within the aquifer at the ISRM barrier were identified with flow measurements from the electromagnetic borehole flowmeter (EBF). Groundwater flowing through these preferential pathways can flush oxygenated waters through the ISRM treatment zone, reducing the reductive capacity of the aquifer. It was recognized that the aquifer heterogeneity needed to be characterized to improve the understanding of depth-discrete variability in physical properties (e.g., hydraulic conductivity). The Technical Assistance Panel identified the electromagnetic borehole flowmeter as one of the tools appropriate for performing the recommended aquifer characterization study.