Barrier Wall Performance 2009 Data
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Transcript of Barrier Wall Performance 2009 Data
Barrier Wall Performance
2009 Data
July 2010 Progress Meeting
McCormick & Baxter Superfund Site
Portland, Oregon
Barrier Wall Performance
• NAPL Recovery– Where and how much
• NAPL Thicknesses– Tracking thicknesses inside and outside wall
• Groundwater and River Elevations– Shallow contour maps– Hydrographs– Gradients
NAPL Recovery
• ROD RA Objectives: contain NAPL, prevent ongoing discharges of NAPL to Willamette River, and minimize further contamination of intermediate and deep aquifers
• Tasks:– Weekly recovery from wells outside barrier wall that
have sufficient NAPL• MW-Ds, MW-Gs, MW-20i (DNAPL only)• EW-1s (inside barrier wall)
– Quarterly gauging for NAPL in remaining wells
Total NAPL Recovery1989-2010 ~6373gallons
Wells with NAPL
Outside Barrier WallMW-20i MW-Gs MW-Ds MW-10s
Inside Barrier WallEW-8s MW-56sEW-18s MW-10rEW-1s EW-15sEW-23s
MW-Ds (outside, FWDA)
MW-Gs (outside, FWDA)
MW-20i (outside, FWDA)
MW-23s (inside, FWDA)
EW-15s (inside, FWDA)
MW-56 (inside, FWDA)
EW-18s (inside, TFA)
NAPL Recovery SummaryOutside Barrier Wall• 2008: 57 gallons of DNAPL from 3 wells (primarily MW-20i);
no LNAPL • 2009: 92 gallons DNAPL (MW-20i, MW-Gs, MW-Ds); no
LNAPL • 2010: 66 gallons DNAPL to date (including EW-1)• NAPL levels remain stable
Inside Barrier Wall – • monitored for NAPL quarterly; • Stable thicknesses • 2009: 21 gallons of DNAPL from EW-1s
Automated NAPL Recovery System - 2011
Groundwater Flow
• Shallow Zone Contour Maps (4 quarters)
• Hydrographs from transducer data (historic and annual)
• Vertical Gradients (using 2008 transducer data)
March 2009
June 2009
September 2009
December 2009 (with Triangle Park)
MW-36s/MW-37sinside/outside
2009 Data MW36/MW37
MW-40/MW-41Inside/Outside
MW44s/MW45sinside/outside
2009 Data MW44/MW45
MW-52s/MW53sinside/outside
Historically, MW-52s gw elevation was ~18.5 NAVD88 (May 2003). The level has gradually dropped since installation of the barrier wall. Rate of decline increased with installation of the impermeable soil cap. Approaching equilibrium with the River
Vertical Gradients
Monitoring WellShallow to
intermediateIntermediate to
deepShallow to
deep
MW-36 (inside) -0.0434 -0.0020 -0.191
MW-37 (outside) -0.0070 0.0022 -0.0015
MW-44 (inside) -0.0841 0.0165 -0.029
MW-45 (outside) -0.0066 0.0017 -0.0018
Main Points• Shallow groundwater within Barrier Wall will equilibrate with the River
(dropped 5 feet – 1-2 more)
• Shallow groundwater outside and inside the barrier wall are not hydraulically connected (i.e., barrier wall is performing as expected)
• GW inside barrier wall is hydraulically connected to the river from the “drain” in corner at base of wall
• Intermediate and deep zones inside and outside the barrier wall continue to mimic river with very low vertical gradients (primarily downward)
• Gradients low and primarily downward: conditions are not conducive to NAPL migrating from inside barrier wall or from MW-20i to River
Barrier wall is performing as designed to prevent NAPL (from within the wall) from migrating to the River; also, significantly reduces the flux of contaminated groundwater to river