Barrier Wall Performance 2009 Data

1. Barrier Wall Performance2009 Data July 2010 Progress Meeting McCormick & Baxter Superfund Site Portland, Oregon

2. 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

3. 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

4. Total NAPL Recovery1989-2010 ~6373gallons

5. Wells with NAPL Outside Barrier Wall MW-20i MW-Gs MW-Ds MW-10s Inside Barrier Wall EW-8s MW-56s EW-18s MW-10r EW-1s EW-15s EW-23s

6. MW-Ds (outside, FWDA)

7. MW-Gs (outside, FWDA)

8. MW-20i (outside, FWDA)

9. MW-23s (inside, FWDA)

10. EW-15s (inside, FWDA)

11. MW-56 (inside, FWDA)

12. EW-18s (inside, TFA)

13. NAPL Recovery Summary Outside 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

14. Groundwater Flow • Shallow Zone Contour Maps (4 quarters) • Hydrographs from transducer data (historic and annual) • Vertical Gradients (using 2008 transducer data)

15. March 2009

16. June 2009

17. September 2009

18. December 2009 (with Triangle Park)

19. MW-36s/MW-37sinside/outside

20. 2009 Data MW36/MW37

21. MW-40/MW-41Inside/Outside

22. MW44s/MW45sinside/outside

23. 2009 Data MW44/MW45

24. 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

25. Vertical Gradients

26. 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