SITE INFORMATION AND CORRESPONDENCE

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I KLE/NFELOER Rtl9RmPk.R19Rt5oluNom. • nursery. This opinion is supported by the consistent lack of water in MW-4s and MW-4d during historical monitoring, and the consistency of the historical shallow perched groundwater gradients coming primarily from Potter Creek in the northwest corner of the nursery. 11. In late November 1999, three deep groundwater monitoring wells were installed within the nursery property. The purpose of the wells was to evaluate groundwater quality of the first aquifer beneath the site at a depth of approximately 150 feet below grade. The reason for evaluating the deeper groundwater was to evaluate the potential for the nursery to be impacting the drinking water wells on the nearby Dodge and Eason properties north of the nursery. The monitoring wells have been sampled on a quarterly basis since their installation. Groundwater gradient was calculated to be 0.003 feet/foot to the southwest during the first and second quarter monitoring event. In general, groundwater flow since December 28, 1999 has been consistently calculated to be 0.003 feet/foot to the southwest. This flow direction matches the San Joaquin County Flood Control and Water Conservation District data detailed in Section 2.4.4. 12. Nitrate-nitrogen was detected in the groundwater samples collected from the deep wells DP-1, DP-2, and DP-3. Reported concentrations ranged from 1.3 (DP-1) to 8.3 (DP-2) mg/I during the first quarter and 1.4 (DP-1) to 6.6 (DP-2) mg/I during the second quarter. The pattern of nitrate concentration distribution in the deep aquifer appears to indicate that the highest nitrate concentrations exist upgradient of the nursery. Both this pattern and the nitrate as N concentrations have been consistent throughout past sampling events. 13. Review of past data regarding deep aquifer groundwater sampling by Kleinfelder and others showed a seasonal trend in the Dodge well. No other trends, seasonal or otherwise, can be ascertained from the data over time. The highest concentrations, with few exceptions, have generally been from the Eason well. According to deep aquifer gradients detailed by the San Joaquin Metropolitan Flood Control and Water Conservation District reports, and to the deep aquifer gradients calculated by Kleinfelder's monitoring of DP-1 through DP-3 to date, flow of the deeper aquifer is towards the southwest. Based on the data plotted, it • 117226.E02/ST012R0696 Page 38 of 43 September 14, 2012 Copyright 2012 Kleinfelder