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Fig. 6. Comparison of water levels measured in Well USGS-118 for two 7-d periods. Barometric pressure in meters of water is shown for comparison. Data collected under isobaric conditions from 3 June 1997 to 10 June 1997 (Box A in Fig. 5). Linear regression of the data gives a slope of 0.0025 m h–1. Data collected from 26 June 1997 to 3 July 1997 (Box B in Fig. 5) begins and ends with isobaric data, while data in the center of the 7-d period (27 June 1997 to 3 July 1997) was collected under nonisobaric conditions. The isobaric portion of the data shows a slope similar to the earlier data (0.0026 m d–1), while the nonisobaric portion actually shows a declining trend (–0.0143 m d–1) of much larger magnitude.
