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 6 of 7 Based on the distance of the remediation system's extraction wells from NP, the volume of water treated by the system(<500 gpm), and the relatively high permeability of the aquifer, it is unlikely that the extraction system would influence the hydraulic gradient in NP wells. The capture zone of the extraction wells, however, may extend beneath the NP site. An increase in TDS levels in the treatment system influent would indicate that higher TDS water originating at the NP site is being captured by the system. Hydrogeologic Setting Geology and hydrogeology of the site and vicinity have been described in detail in previous reports.5 Briefly, the Mill is located in the East San Joaquin Groundwater Basin and is underlain by a sequence of Tertiary- and Quaternary-aged continental deposits of the Tulare Formation. These deposits consist of interbedded sands/gravels and silts/clays or mixtures thereof. Four distinct aquifers or zones have been identified beneath the site and have been designated by L&A as the semiperched, upper, intermediate, and lower zones. The semiperched zone is unconfined and occurs from approximately 35 to 60 feet below ground surface (bgs). All other zones are semiconfined to confined. The upper zone occurs from approximately 85 to 110 feet bgs, the intermediate zone from 140 to 225 feet bgs, and the deep zone from 240 to greater than 300 feet bgs. Permeability in the aquifer zones has been estimated at approximately 525 gpd/ft2; permeability in the confining layers has been estimated at 3.5 gpd/ft2.6 Groundwater movement in the semiperched and upper semiconfined zones in the vicinity of Ripon is generally to the west.7 North of Ripon, groundwater moves to the north. Southwest of Ripon, on the southwest side of the San Joaquin River, groundwater also moves to the north, towards the river. Summary of Work Performed Depth to Groundwater The depth to groundwater was measured in all wells prior to purging and sampling using an Actat Model 300 electric well probe. The depth to groundwater was recorded to the nearest 0.01 foot(Table 2). Purging Procedures All wells (except well PW-4,which has a dedicated submersible pump)were purged using either a submersible Grundfos MPI 2-inch pump or an Enviro-Tech ES-60 1.875-inch PVC pump set up to 20 feet below the surface of the groundwater. Prior to sampling, each well was purged of three casing volumes of water or until field parameters stabilized. Purged water from wells TH-7 through TH-10 and wells M-7-A, M-11-A, M-11-C, and M-19-C were transported to Nestles' Stockton Avenue groundwater-treatment system in Ripon for disposal because TCE or various TCE daughter products have been detected in these wells. Purged water from all other wells was disposed by direct discharge to the ground surface and allowed to infiltrate/evaporate. 5 L&A,May 5, 1992,Impacts on Receiving Waters from Discharge at the Simpson Paper Company Facility, Ripon, California. 'Ibid., P.27. 7Ibid., Fig. 3. 005194.04 Task 4 Lawrence&Associates W.•I CLIENTSIFoxRiver-NeenahlQuarterlyMonitoringl201011st half 2010 reporkdoc