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• 0 <br /> Review of the Draft FFA Annual Progress Report: <br /> October 2005 through September 2006 <br /> DDJC Sharpe Site <br /> Lathrop, California <br /> December 2006 <br /> GENERAL COMMENT <br /> 1. Some of the wells proposed for no further sampling may benefit from one additional <br /> sample to allow for a statistical trend analysis of existing data as discussed in the January <br /> meeting. For example,this FFA Annual Progress Report: October 2005 through <br /> September 2006 (Annual Report)proposes to eliminate arsenic sampling for extraction <br /> well EWC4. To conduct a statistical trend analysis four results are usually needed and <br /> currently there are three arsenic results for EWC4. As part of the decision to eliminate <br /> sampling from a well, the collection of an additional sample should be considered if <br /> useful information would be obtained from running a statistical trend analysis. <br /> SPECIFIC COMMENTS <br /> 1. Section 1.0,Introduction,Page 1-1: It isnot clear from the introduction why the <br /> Annual Report only summarizes the results of two quarters (fourth quarter of 2005 <br /> [4Q05] and 3Q06) and not four quarters of groundwater monitoring events as seen in past <br /> annual reports. It is stated in Section 3.1.1 the 1Q06 and 2Q06 sampling events were not <br /> performed due to contractual and funding constraints. However, it appears the Annual <br /> Report would be more user friendly if this was discussed earlier. The same clarification <br /> could be added to the executive summary on page ES-1. In addition, it is not stated in the <br /> text if any wells were not sampled as a result of the cancellation of the 1 Q06 and 2Q06 <br /> sampling events. Please clarify in the Introduction and Executive Summary why only <br /> two and not four quarters are summarized in this Annual Report and briefly state in the <br /> text if any wells were not sampled at all in the past year due to the cancellation of the <br /> 1Q06 and 2Q06 sampling events. <br /> 2. Section 4, Attachment 1,Results of Simulations of 3Q06 Conditions with DDJC- <br /> Sharpe Groundwater Flow Model, Table 2, Summary of Results of Simulations for <br /> 3Q06 Particle Tracking Using DDJC-Sharpe Groundwater Flow Model,Page 7: <br /> The"Notes on Results" in the table on particle capture in 30 years for layer 1 appears to <br /> be contradicted by the results shown on Figure 4, 3Q06, Layer 1 South Balloon and <br /> Central Area,DDJC-Sharpe. The "Notes on Results" in Table 2 for layer 1 in the central <br /> area states, "All particles are captured in 30 years." However,Figure 4 for the central <br /> area appears to show two layer 1 particles, originating in the northern half of the lager <br /> plume,not captured and migrating to a deeper layer within 30 years. One particle, <br /> originating in the northwest portion of the plume, appears to migrate southwest then <br /> northwest and vertically into layer 3 (the particle path is shown in green). The second <br />