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Peter MacNicholl February 24, 2003 Page 3 6. Page 4-10, Section 4.7. The section discusses off-installation contamination but does not discuss if there are any treatment units on any of the private wells. If a treatment unit exists for a private well, include a discussion on the last time the unit was checked, when the last carbon change-out occurred and report the sample results after treatment. 7. Page 5-3, Section 5.2.2.3. Rather than relying only on water elevation contours to estimate capture areas, DTSC recommends including a spreadsheet using some site-specific generalized hydraulic information that estimate hydraulic capture zones from extraction wells. Using both the capture zone calculations and water elevations helps provide a lines-of-evidence approach for establishing the extent of hydraulic capture. 8. Page 5-4, Section 5.2.2.5. The text indicates that incomplete capture is attributed to insufficient extraction rates due to reduced or no pumping. The text should clarify if the reduced extraction rates or lack of pumping was solely due to the system breakdowns (pump failures, berm failures, etc.) Indicate if this lack of capture is an ongoing issue or if previous quarterly operations actually showed complete capture. 9. Sections 5.2.2.6 through 5.2.2.9. The percentage of plume capture provided in each section would be better provided in a table or graphical format. The text sections should explain the reason for significant (>10%) differences between the quarters. 10. Section 5.2.2.6. The text states that 3Q02 showed the eastern TCE plume as 44% captured but the same TCE plume was not captured in 3Q01. Provide the percentage of capture in 3Q01 to allow for a relative comparison of capture. If the 3Q01 capture was at 60% capture and the 3Q02 is at 44%, provide possible reasons for the difference. 1.1. Section 5.2.2.7. Provide the percentage of plume capture for the eastern PCE plume.