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The fourth quarter 2012 field turbidity value at AMW-5R (386 NTUs) is consistent with the range of values observed at that well since May 1995 (<0.01 to >1000 NTUs), and is the lowest turbidity values observed at that well since August 2010. The increasing trend for field turbidity at AMW-5R is not observed when the data are limited to the period of November 2005 to November 2012, indicating that values have stabilized in the past seven years. The fourth quarter 2012 field turbidity value at AMW-10 (155 NTUs) is within with the range of values observed at that well since May 1995 (<0.01 to 783 NTUs). The increasing trend for field turbidity at AMW- 10 is not observed when the data are limited to the period of November 1997 to November 2012, indicating that values have stabilized in the past fifteen years. The fourth quarter 2012 concentration of 1,1-dichloroethane at AMW-1 (3.3 ug/L) is within the range of concentrations observed at that well since September 1994 (<0.2 to 7.9 ug/L), and is below the California Maximum Contaminant Level. There is no established National Primary Drinking Water Standard for 1,1-dichloroethane. The increasing trend for 1,1-dichloroethane at AMW-1 is not observed when the data are limited to the period of November 1999 to November 2012, indicating that concentrations have stabilized in the past thirteen years. The fourth quarter 2012 concentration of 1,2 -dichlorobenzene at AMW-1 (0.45 ug/L) is within the range of concentrations observed at that well since the first detection in May 2004 (<0.5 to 1 ug/L), and is well below the National Primary Drinking Water Standard of 600 ug/L. The increasing trend for 1,2 -dichlorobenzene at AMW-1 is not observed when the data are limited to the period of May 2008 to November 2012, indicating that concentrations have stabilized in the past four years. The fourth quarter 2012 concentration of chlorobenzene at AMW-1 (1.4 ug/L) is within the range of concentrations observed at that well since the first detection in July 1999 (<0.5 to 2.2 ug/L), and is below the National Primary Drinking Water Standard of 100 ug/L. The increasing trend for chlorobenzene at AMW-1 is not observed when the data are limited to the period of August 2009 to November 2012, indicating that concentrations have stabilized in the past three years. The fourth quarter 2012 concentration of cis-l,2-dichloroethene at AMW-1 (7.6 ug/L) is within the range of concentrations observed at that well since April 1995 (<O.18 to 50 ug/L), and is below the National Primary Drinking Water Standard of 70 ug/L. The increasing trend for cis- 1,2-dichloroethene at AMW-1 is not observed when the data are limited to the period of November 2006 to November 2012, indicating that concentrations have stabilized in the past six years. Piper diagrams of the first through fourth quarter 2012 results for the corrective action monitoring wells are presented in Appendix H. Hydrographs of the corrective action monitoring wells, illustrating historic groundwater elevations, well screen elevations, and pump intake elevations, are included in Appendix I. 0