ARCHIVED REPORTS_FIRST QUARTER 2008 GROUNDWATER MONITORING REPORT

Home Browse Search

Neenah Paper,Inc. _First-Quarter 2008 Groundwater-Monitoring Repnrl ApH130,2008 Pape 3 of 9 An east-west trending ridge was present in the northwest corner and west central portions of the site within the upper aquifer; additionally, the influence of the Nestles' groundwater-extraction • well was evident from the depression of the groundwater gradient north of the site. The direction of the groundwater gradient was away from the ridge at a magnitude of 0.0018 ft/ft (Figure 4). Mounding within the intermediate aquifer was present west central portion of NP and in the vicinity of the City of Ripon's MW WTF ponds. The influence of Nestles' Stockton Avenue groundwater-extraction wells north of the site was evident by the depression in the surface of the groundwater gradient. The magnitude of the gradient ranged between 0.0008 and 0.0012 ft/ft (Figure 5). The areas of highest SC in the semiperched aquifer were in the northeast corner of the site in well 013-4 (2,588 µmhos/cm), along the northwestern property boundary in M-1 1-B (1,534 µmhos/cm) and OB-I (1,523), between the aeration basins in monitoring well OB-11 (1,612 µmhos/cm) and in the southwest quadrant of the site in OB-25 (1,480 µmhos/cm; Figure 6). With the exception of well TH-4 (1,690 µmhos/cm), SC levels in all other wells screened in the upper aquifer were in compliance with the WQPS of 1,580 µmhos/cm (Table 1). The area of lowest SC was in the southeastern comer of the site along the Stanislaus River in well TH-5 (93 µmhos/cm; Figure 7). The area of highest conductivity in the intermediate aquifer was in the northeastern corner of the site in NP's well PW-4 (1,694 µmhos/cm);the area of lowest conductivity was in the southeastern corner of the site along the Stanislaus River in well M-3 1-C (350 µmhos/cm; • Figure 8). The areas of highest and lowest total dissolved solids (TDS) concentrations in the semiperched (Figure 9), upper (Figure 10), and intermediate aquifers (Figure 11) were approximately the same as the areas of highest and lowest field conductivity values in the semiperched (Figure 6), upper(Figure 7), and intermediate aquifer(Figure 8). Conclusions The application of plant-process water for the irrigation of tree orchards and the potential infiltration from the process-water ponds and aeration basins, is thought to have caused groundwater mounding in the semiperched, upper, and intermediate aquifers (Figures 3, 4 and 5). 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 groundwater in the northeastern quadrant of the site, which are over three times higher than effluent TDS levels, are likely 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. Comparing OB-4's TDS values to the TDS values from ASB-2, groundwater TDS shows a roughly similar proportion to that cited above— ASB-2 is about 600 to 800 mg/L, groundwater is about 2,100 mg/L. • 4 G.S. Jorgensen, Kenneth H. Solomon,and V. Cervinka,March 1993,Agroforestty Systems for On-Farm Drain Water Management. 005194.01 Task 8 Lawrence&Associates R:•1Clients1FoxRiver-NeenahlQuarteri.vMonitoringl2008llst quarterllst Q2008 report-due