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Jim Pinasco <br /> June 21, 1994 <br /> Page 6 <br /> wells will not be used in the future, then they should be <br /> decommissioned in accordance with a DTSC approved work plan. <br /> SPECIFIC COMMENTS <br /> 7 . Figure 3-3, Geologic Cross-Section A-A' ; Figure 5-9, <br /> Vertical Extent of TCE Plume, October 1993 Round, Cross- <br /> Section A-A' ; Figure 3-5, Geologic Cross-Section C-C' ; <br /> Figure 5-10, Vertical Extent of TCE Plume, October 1993 <br /> Round, Cross-Section C-C' <br /> Well LM48C is the point of intersection between geologic <br /> cross-sections A-A' and C-C' . However, the stratigraphy does not <br /> completely match on the two cross-sections. Cross-section A-A' <br /> shows a clay (CL) unit around 0 to 20 feet below sea level at <br /> LM48C that does not match the clayey sand (SC) unit at the same <br /> depths on cross section C-C' . <br /> Overall the cross-sections are well done, however, the <br /> vertical scales change on different cross-sections (e.g. , <br /> cross-section A-A' and C-C' have different vertical scales) . It <br /> is also difficult to determine to which well the indicated ground <br /> water level applies, especially in closely spaced well clusters. <br /> Recommendations <br /> The lithology for the same well should be the same on all <br /> cross-sections. Cross-sections A-A' and C-C' should be revised <br /> to have the same lithology at LM48A. The cross-sections should <br /> be reviewed to ensure that all wells used on more than one cross- <br /> section are the same on each cross-section. If possible, the <br /> vertical scale should be the same for all of the cross-sections <br /> to facilitate integration and three-dimensional interpretation. <br /> Some kind of indicator or footnote should identify to which wells <br /> or hydrologic horizons the indicated water levels apply. <br /> 8. Effects of Precipitation on Historic Groundwater Elevations, <br /> Section 3 .2 . 6. 2, page 3-29; Figures 3-11, Precipitation <br /> Effects on Above Upper Horizon Groundwater Elevations; and <br /> Figure 3-12, Precipitation Effects on Upper Horizon <br /> Groundwater Elevations <br /> The Report states in Section 3 .2 . 6.2 on page 3-29, "highest <br /> monthly rainfall total, 4.91 inches, occurred in January 1993. " <br /> However, Figures 3-11 and 3-12 show the greatest precipitation in <br /> MS.kl <br /> MS63.064/10B <br />