1. Presented by Michael Taraszki, PG, CHG Engineering and Consulting, Inc. Perchlorate Monitoring in the Llagas Groundwater Subbasin South Santa Clara County, California Olin/Standard Fusee Case Study

2. NWQMC, San Jose, CA, May 11, 2006 Outline Investigation History Current Cleanup and Abatement Order (CAO) Characterization Elements and Challenges Status of Investigation

3. NWQMC, San Jose, CA, May 11, 2006 Investigation History Perchlorate Tested/Observed Beneath Morgan Hill Site in 2000 Site Investigation Expanded to Include Offsite Private Wells Continued Presence of Perchlorate Required Rapid Expansion of Monitoring Program Over 200 Wells >PHG (6  g/L) by 2004 Only 33 Wells >PHG Currently

4. NWQMC, San Jose, CA, May 11, 2006

5. GW Flow PerchlorateNon-Detect

6. NWQMC, San Jose, CA, May 11, 2006 GW Flow Perchlorate >4  g/L 4  g/L <6  g/L

7. NWQMC, San Jose, CA, May 11, 2006 GW Flow Perchlorate >6  g/L

8. NWQMC, San Jose, CA, May 11, 2006 GW Flow All Perchlorate Results

9. NWQMC, San Jose, CA, May 11, 2006 Investigation Overview Current Cleanup and Abatement Order Requirements Characterization Elements –Lateral/Vertical Extent of Perchlorate –Background Concentration Evaluation –Establish GW Flow Directions, Chemical Signatures, and Aquifer Hydraulic Parameters Characterization Challenges –Large Scale Project –Significant Technical Issues –Aggressive Schedule –Politically Charged Arena Investigation Status

10. NWQMC, San Jose, CA, May 11, 2006 Evaluate Existing Data Acquire New Data Chemistry Geology Hydrogeology Identify Limitations CHARACTERIZATION

11. Detailed Logging of Soil Core

12. NWQMC, San Jose, CA, May 11, 2006 Near In-Situ Conditions Near 100% Recovery Plastic Wrapping Allows for Labeling Boxed for Long-Term Storage Soil Core Benefits:

13. NWQMC, San Jose, CA, May 11, 2006

15. Depth-Discrete Slug Testing

16. NWQMC, San Jose, CA, May 11, 2006 Aquifer Hydraulic Testing In-Situ Drill-String Slug Testing –Conducted During Drilling Activities –208 Tests Performed to Date Pneumatic Slug Testing –Conducted In Completed 1-Inch PVC Wells ‘Passive’ Pumping Response Analysis –Continuously Recorded Water Levels

17. NWQMC, San Jose, CA, May 11, 2006 Slug Test Results Shallow Intermediate Deep

18. Installing Multi-Level Monitoring Wells

19. NWQMC, San Jose, CA, May 11, 2006 Mixture of Techniques 0 300 400 450 100 200 Depth (ft) Initial Borehole & PVC Couplet Second Borehole & CMT Well Casing Borehole Screen Result: Up To Nine Depth-Discrete Intervals at Each Location

20. NWQMC, San Jose, CA, May 11, 2006 Monitoring Well Design Base Design Upon Geologic Log of Continuous Core Target Zones with Highest Permeability CMT Well Design Begins with Evaluation of First 300-Feet of Primary Borehole PVC Couplet Designed CMT Design Confirmed with Evaluation of Secondary Borehole Designs Coordinated with RWQCB and SCVWD

21. NWQMC, San Jose, CA, May 11, 2006 CMT Installation: Step 1 Layout Work Area

22. NWQMC, San Jose, CA, May 11, 2006 CMT Installation: Step 2 Prepare 300-Foot CMT Coil

23. NWQMC, San Jose, CA, May 11, 2006 CMT Installation: Step 3 Uncoil CMT Material

24. NWQMC, San Jose, CA, May 11, 2006 CMT Installation: Step 4 Install Monitoring Ports

25. NWQMC, San Jose, CA, May 11, 2006 CMT Installation: Step 5 Install Port Screens

26. NWQMC, San Jose, CA, May 11, 2006 CMT Installation: Step 6 Backfill Void Space

27. NWQMC, San Jose, CA, May 11, 2006 CMT Installation: Step 7 Install Bottom Plugs

28. NWQMC, San Jose, CA, May 11, 2006 CMT Wellhead Seven Monitoring Ports Protective PVC Sleeve Sand Drainage

29. NWQMC, San Jose, CA, May 11, 2006 PVC Couplet Wellhead (in progress)

30. NWQMC, San Jose, CA, May 11, 2006 Completed Well Diagrams 0 300 400 450 100 200 Depth (ft) Initial Borehole & PVC Couplet Second Borehole & CMT Well Casing Borehole Screen Result: Up To Nine Depth-Discrete Intervals at Each Location

31. Depth-Discrete Groundwater Elevation and Analytical Data

32. NWQMC, San Jose, CA, May 11, 2006 GW Elevation Evaluation Monitoring Well Elevation Data Will Be Used to Identify: –Vertical Distinction of Aquifer Units –Local Pumping Influences –Depth-Discrete Horizontal Gradients –Utility of Supply Wells

33. NWQMC, San Jose, CA, May 11, 2006

35. Cross-Section and Groundwater Elevations Northern Half

36. NWQMC, San Jose, CA, May 11, 2006 Cross-Section and Groundwater Elevations Southern Half

37. NWQMC, San Jose, CA, May 11, 2006 Offsite Perchlorate Shallow Aquifer

38. NWQMC, San Jose, CA, May 11, 2006 Offsite Perchlorate Intermediate Aquifer

39. NWQMC, San Jose, CA, May 11, 2006 Offsite Perchlorate Deep Aquifer

40. NWQMC, San Jose, CA, May 11, 2006 Summary Data Evaluation –Continuous Soil Core –Groundwater Flow Directions –Aquifer Hydraulic Parameters –Perchlorate Distribution/Chemical Signatures Significant Challenges Being Addressed with Innovative Approaches –Sonic Drilling/Continuous Soil Cores –Multi-Level Monitoring Well Technology –Depth-Discrete Aquifer Testing Aggressive Investigation Schedule

41. Contact Information: Michael Taraszki 600 Grand Avenue, Suite 300 Oakland, California 94610 (510) 628-3222 mdtaraszki@mactec.com Petaluma Office: 5341 Old Redwood Hwy, Ste 300 Petaluma, CA 94954 Phone: (707) 793-3800 Fax: (707) 793-3900 San Francisco Office: 28 Second Street, Suite 700 San Francisco, CA 94105 Phone: (415) 543-8422 Fax: (415) 777-9706 Sacramento Office: 4704 Roseville Road, Suite 108, North Highlands, CA 95660 Phone: (916) 332-5552Fax: (916) 332-5559 www.mactec.com