Thirty-two water level measurements were recorded during the September 2002 monitoring event. Water level measurements were taken in CSSA wells CS-1, CS-2, CS-3, CS-4, CS-9, CS-10, CS-11, CS-MW16-LGR, CS-D, CS-G, CS-H, CS-I, CS-MW1-LGR, CS-MW2-LGR, CS-MW3-LGR, CS-MW4-LGR, CS-MW5-LGR, CS-MW6-LGR, CS-MW6-CC, CS-MW6-BS, CS-MW7-LGR, CS-MW7-CC, CS-MW8-LGR, CS-MW8-CC, CS-MW9-LGR, CS-MW9-CC, CS-MW9-BS, CS-MW10-LGR, CS-MW10-CC, CS-MW17-LGR, CS-MW18-LGR, and CS-MW19-LGR. All water levels were measured with an e-line water level indicator. Transducer data was also collected from wells CS-MW16-LGR, CS-MW9-LGR, CS-MW9-BS, CS-MW9-CC, and CS-MW4-LGR. Transducer data is discussed in Section 3.0. An average groundwater elevation for well FO-20 from the week of September 9, 2002, was obtained from Fair Oaks Water Utilities.

On average, groundwater levels increased 104.50 feet between the last on-post monitoring event, June 17, 2002 and September 9, 2002. This overall increase was calculated by averaging the groundwater elevation changes for all wells, including those screened across multiple formations. Groundwater depths derived from water level measurements are compared to top of casing elevations and are summarized in Table 1-1. Table 1-2 summarizes the changes in groundwater elevations since the June 2002 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).

An average groundwater elevation for each formation present in the subsurface at CSSA is provided in Table 1-1. This average was calculated using the groundwater elevations from wells screened in only one formation. Wells completed with open boreholes over multiple formations were not used. Typically, the water levels measured at CSSA decrease from the Lower Glen Rose to the Bexar Shale to the Cow Creek. The average groundwater elevations in September 2002 for the Lower Glen Rose, Bexar Shale, and Cow Creek were 1130.87 feet, 1129.21 feet, and 1098.34 feet, respectively, an increase of 100.36 feet in the Lower Glen Rose, 106.70 feet in the Bexar Shale, and 104.32 feet in the Cow Creek from the average levels measured in June 2002. Evaluation of trends in water level elevations in the different units will continue as additional wells are installed. Newly installed wells CS-MW17-LGR, CS-MW-18-LGR, and CS-MW19-LGR were not included in the above calculations because the top of casing elevations had not been surveyed.

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