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Remedial Investigation QAPP Stockton Army Aviation Support Facility,California displacement versus time and estimates of hydraulic conductivity will be generated.The field procedures for slug testing are presented in Worksheet #14. For additional details, refer to Parsons SOP PFAS ENV-07 Hydraulic Conductivity(Slug) Testing(Appendix D). 17.6 Surface Water, Sediment, Stormwater, and Stormwater- Transported Solids Sampling Design and Rationale During RI Mobilization 1, a total of six surface soil samples will be collected from the Rydberg Creek stormwater conveyance to determine if PFAS impacts are present. Rydberg Creek is ephemeral and dry except during precipitation events. If surface runoff water is not present during Mobilization 1, surface soil samples will be collected at various points adjacent to the Facility along the Rydberg Creek conveyance, following surface soil sampling procedures, as described in Section 14.2.2. If water is present during Mobilization 1, stormwater and soil samples will be collected from the channel. The approximate locations of Rydberg Creek stormwater conveyance samples are shown on Figure 17-3; however, the locations may be adjusted in the field based on existing field conditions. The rationale for the sample locations and sample depths are provided in Table 17-5.Surface soil samples(or if present and collected during Mobilization 1, surface water and sediment samples) will be analyzed under standard TAT for the target list of 40 PFAS by USEPA Method 1633, as specified in Worksheet#15. Additionally, if sediment samples are collected, 25% of sediment samples will be analyzed for TOC (USEPA Method 9060A), pH (USEPA Method 9045D), and grain size with sieve and hydrometer(ASTM D-422). The sediment samples analyzed for TOC, pH, and grain size will be selected to represent the range of habitat and substrate types available at the sampling locations.The procedures for the collection of surface soils,surface water,and sediment samples are presented in Worksheet#14. The sampling procedures are further detailed in Parsons SOP PFAS ENV-02 Soil Sampling and SOP PFAS ENV-04 Surface Water and Sediment Sampling(Appendix D). 17.7 Synoptic Groundwater Gauging Design and Rationale Groundwater levels will be collected from newly installed permanent groundwater monitoring wells and from 3 existing monitoring wells associated with the FMS#24 petroleum site investigation (Figure 17-2).The proposed monitoring well locations are included in Table 17-4 and are shown on Figure 17-2.The procedures for collection of water levels from monitoring wells are presented in Worksheet#14. The groundwater gauging round will be conducted within as short a time period as reasonably feasible (typically within one working day) and will follow a period of little to no precipitation. PARSONS Worksheet#17&18:Sampling Design and Rationale Page 116