ARCHIVED REPORTS_FIRST-HALF 2010 GROUNDWATER MONITORING REPORT 07-27-2010

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Neenah Paper,Inc. July 27,2010 First-Half 2010 Groundwater-Monitoring Report Page 4 of 7 the aeration basins in monitoring well OB-11 (1,601 µmhos/cm) and in the southwest quadrant of the site in OB-25 (1,515 µmhos/cm); the area of lowest SC was in the southeastern corner of the site along the Stanislaus River in well OB-16 (82 µmhos/cm; Figure 9). With the exceptions of well TH-3 (1,933), SC levels in all wells screened in the upper aquifer were in compliance with the WQPS of 1,580 µmhos/cm(Table 2). The area of lowest SC was in the southeastern corner of the site along the Stanislaus River in well TH-5 (191 µmhos/cm; Figure 10). The area of highest SC in the intermediate aquifer was in the northwest corner of the site in TH- 8 (1142 µmhos/cm); the area of lowest SC was adjacent to the Stanislaus River in well TH-10 (673 µmhos/cm; Figure 11). The areas of highest and lowest total dissolved solids (TDS) concentrations in the semiperched (Figure 12),upper(Figure 13), and intermediate aquifers (Figure 14)were approximately the same as the areas of highest and lowest field SC values in the semiperched(Figure 9), upper (Figure 10), and intermediate aquifer(Figure 11). Conclusions The reduced volume of water NP currently is spreading around the site appears insufficient to maintain the groundwater mound which has historically been present in the semiperched, upper, and intermediate aquifers and the historical northwesterly groundwater gradient is once again dominant (Figures 6 to 8). Infiltration of plant process water is suspected to be responsible for the elevated conductivity levels measured in the semiperched, upper, and intermediate aquifer over most of the site, however, the elevated TDS levels in the semiperched aquifer in the northeastern quadrant of the site, which have been up to three times higher than effluent TDS levels, are potentially caused by the eucalyptus trees planted in this area(Figure 9).4 Jorgensen et al., determined that eucalyptus trees uptake large volumes of groundwater and can actually depress the surface of the groundwater while simultaneously concentrating TDS up to 3.2 times. Groundwater with TDS levels higher than WQPS has encroached in the southwest quadrant of the NP site as recharge from the City of Ripon's MWWTF moves easterly towards the NP site. Recommendations NP should continue to use low TDS water to dilute the effluent stream from the Cogen and irrigate the east percolation field during the 2010 irrigation season. If the site is to continue treating and discharging wastewater, consideration should be given to removing the eucalyptus groves in order to eliminate their concentrating effect on groundwater TDS levels. Paper production has ceased and NP plans to divest of the site. Given that the future use of the site is unknown and presently there are no plans to accept and discharge wastewater beyond the end of 2010, a decision regarding the eucalyptus trees should be delayed until such time as the future use of the site can be ascertained. 4 G.S.Jorgensen,Kenneth H.Solomon,and V.Cervinka,March 1993,Agroforestry Systems for On-Farm Drain Water Management. 005194.04 Task 4 Lawrence&Associates W.•I CLIENTSIFoxRiver-NeenahlQuarterlyMonitoringl201011st half 2010 reporkdoc