SU0004126 - Laserfiche WebLink

Home Browse Search

5 recovery by late fall (Figure 2). Ground-water depths and elevations measured in all wells during each quarter of the three years of monitoring are presented in Table 1. In comparison to the shallow wells, ground-water levels in the deep wells were deeper and fluctuated more throughout the last three years, presumably in response to pumping of those and/or other nearby deep wells during that time. The static water levels in the Petz irrigation well have fluctuated seasonally approximately 5 to 10 feet, with the lowest observed levels during t' the fall and highest levels in the winter (Figure 3). Static water levels in the South Tracy #1 production well have fluctuated as much as 35 feet during 1994, 1995, and 1996 and a pumping level observed in March 1994 was 75 feet below the lowest static water level (Figure 4). Static water levels have been measured in the Brown's #1 production well since January 1995 (during the beginning of 1994, water levels could not be measured because the well was being pumped at the time and the pumping levels were deeper than the length of the sounder) and these water levels are well below shallow ground-water levels. Measurement of the water level in the Ponderosa production well has not been possible due to a blocked airline. The airline of the Brown's New production well was repaired in mid-1996, facilitating water-level measurements from the well during the last three quarters. However, these measurements are not consistent and may indicate that there is a problem with the airline or its reported length. The ground-water elevations and fluctuations observed during the last three years of monitoring illustrate the difference between the shallow and deep zones beneath the monitoring network area. In the shallow wells, ground-water elevations have ranged from 76 to 86 feet MSL across the area with generally less than three feet of seasonal fluctuation, indicating the upper zone (above ,r..� the confining clay) is an unconfined or "water table" aquifer. Alternatively, in the deep wells (i.e., those completed below the base of the confining clay, which is at an approximate elevation of 75 feet below mean sea level), static ground-water elevations have ranged from 17 feet below mean sea level to 50 feet MSL across the area. These ground-water elevations combined with a t" observed fluctuations as great as 35 feet indicate the lower zone is a confined aquifer and that a downward vertical gradient exists between the upper and lower zones. © LUHOORFF & SCALMANINI 1 f - C O N S U L T I N G ENG f N E E R 5