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December 2004 On-Post Quarterly Groundwater Monitoring Report
Section 1 - Water Level Measurements
Groundwater monitoring scoped under the Air Force Center for Environmental Excellence (AFCEE) 4P/AE Contract 41624-03-D-8613, Task Order (TO) 0008, was performed during the weeks of November 29, 2004 and December 10, 2004, at Camp Stanley Storage Activity (CSSA). On-Post groundwater monitoring conducted under this TO began with the September 2003 sampling event. Groundwater monitoring conducted prior to September 2003 was conducted under various delivery orders as shown in Table 1 of the Introduction to the Groundwater Monitoring Program, Volume 5. AFCEE provides technical oversight of the monitoring program.
Current objectives of the groundwater monitoring program are to determine groundwater flow direction and elevations, determine groundwater contaminant concentrations for characterization purposes, and identify meteorological and seasonal variations in physical and chemical properties. Appendix A identifies the data quality objectives (DQO) for CSSA�s groundwater monitoring program, along with an evaluation of whether each DQO was attained. The objectives listed in the table also reference appropriate sections of the 3008(h) Administrative Order on Consent (Order). Overall DQOs for the investigations at CSSA are provided in Volume 1-1 behind the RFI Addendum tab (Section 11).
1.0 - Water Level Measurements
Forty water level measurements were recorded on December 2 and 3, 2004. Water level measurements were collected from CSSA wells CS-1, CS‑2, CS-3, CS‑4, CS‑10, CS‑11, CS‑MW16‑LGR, CS‑MW16‑CC, CS‑D, CS‑MWG‑LGR, CS‑MWH‑LGR, CS‑I, CS‑MW1‑LGR, CS-MW1‑BS, CS‑MW1‑CC, CS‑MW2‑LGR, CS‑MW2‑CC, CS‑MW3‑LGR, CS-MW4‑LGR, CS‑MW5‑LGR, CS‑MW6‑LGR, CS‑MW6‑BS, CS‑MW6‑CC, CS-MW7‑LGR, CS‑MW7‑CC, CS‑MW8‑LGR, CS‑MW8‑CC, CS‑MW9‑LGR, CS‑MW9‑BS, CS‑MW9‑CC, CS‑MW10‑LGR, CS‑MW10‑CC, CS‑MW11A-LGR, CS‑MW11B‑LGR, CS‑MW12‑LGR, CS‑MW12‑BS, CS‑MW12‑CC, CS‑MW17‑LGR, CS‑MW18‑LGR, and CS‑MW19‑LGR. A water level was not collected from CS‑9 due to a downhole obstruction. All water levels were measured with an e-line water level indicator. Transducer data were also collected from wells CS‑1, CS‑10, CS‑11, CS‑MW1‑CC, CS‑MW2‑CC, CS-MW4-LGR, CS-MW8-LGR, CS‑MW8-CC, CS‑MW9‑LGR, CS‑MW9‑BS, CS-MW9-CC, CS‑MW11A‑LGR, CS‑MW11B‑LGR, CS‑MW12‑CC, CS‑MW16‑LGR, CS‑MW16‑CC, CS-MW18-LGR, and CS‑MW19‑LGR. Transducer data are discussed in further detail in Section 3.0. A groundwater elevation for off-post well FO‑20 was obtained from Fair Oaks Water Utilities on December 3, 2004. Measurements were also collected from off-post wells LS-7 and RFR-10.
Depth to groundwater subtracted from top of casing elevations and the water level elevations are summarized in Table 1‑1. Table 1‑1 includes the most recent survey data provided by Baker Surveying. Table 1‑2 summarizes the changes in groundwater elevations compared to the September 2004 event. The current groundwater elevations may be compared to the historical groundwater elevations from October 1992 through the most recent groundwater monitoring event in Table 3 of the Introduction to the Quarterly Groundwater Monitoring Program (Parsons, 2002) (Volume 5, Groundwater).
The average groundwater elevation measurement for each of the Lower Glen Rose (LGR), Bexar Shale (BS), and Cow Creek Limestone (CC) Formations is provided in Table 1‑1. The averages were calculated using groundwater elevations from wells screened in only one formation. Water elevations from wells completed with open boreholes over multiple formations were not used. Typically, water levels measured at CSSA decrease in elevation from the LGR to the BS to the CC. In December 2004, the average groundwater elevation followed the typical pattern. The average groundwater elevations in December 2004 for the LGR, BS, and CC were 1173.97 feet, 1159.46 feet, and 1135.16 feet above mean sea level (MSL), respectively. This was an increase of 65.21 feet in the LGR, an increase of 49.29 feet in the BS, and an increase of 60.20 feet in the CC from the average levels measured in September 2004.