WORK PLANS - Laserfiche WebLink

Home Browse Search

r Kennedy/Jenks Consuhants There are seven monitoring wells completed in the shallow groundwater zone at depths between 20 and 75 feet bgs in the vicinity of the Title 27 ponds. The wells have been monitored quarterly for the presence of water, in accordance with the WDRs. The monitoring dataset clearly documents that groundwater has not been observed in the shallow groundwater zone in the vicinity of the Title 27 ponds since 2006 when the most recent monitoring wells were installed. 3.1.2 Intermediate Zone In the vicinity of the Title 27 ponds, groundwater that is encountered between approximately 80 and 120 feet bgs is considered intermediate depth groundwater(the intermediate zone). Groundwater monitoring wells that have historically monitored this zone include Wells MW-1 OR, MW-12, MW-18, and MW-22. As noted above, all of these wells, with the exception of Well MW-18 were completed in the first encountered groundwater. Well MW-10R was installed in June 2007 to a depth of 100 feet bgs.Well MW-1 OR was installed to first encountered groundwater as a replacement to Well MW-10 which had previously gone dry. Well MW-1 OR is an active groundwater monitoring well yielding quarterly water quality samples. Although it is currently active,the groundwater elevation in this well has been steadily decreasing throughout its monitoring history at a rate of approximately two feet per year. Based upon a projection of the declining trend in water levels, Well MW-1 OR is expected to become dry in early/mid-2014. Well MW-12 was installed in April 2002 to a depth of 100 feet bgs. Well MW-12 yielded quarterly groundwater samples until October 2009. During the January 2010 sampling event, it was noted that water levels had declined. The well was purged to initiate the sample collection process, but recharge extended over a period of several weeks, and a sufficient sample could not be recovered. Since January 2010, the water level in Well MW-12 continues to be monitored and the well is purged quarterly in effort to obtain a representative sample. Well MW-18 was installed in June 2005 to a depth of 100 feet bgs. Well MW-18 was installed to second encountered groundwater, targeting the intermediate zone, and is located approximately 10 feet south of Well MW-17. Well MW-18 yielded quarterly groundwater samples until April 2009 and was first noted as dry in July 2009. Well MW-22 was installed in October 2006 to a depth of 110 feet bgs.Well MW-22 is currently an active groundwater monitoring well, yielding quarterly water quality samples. Although it is currently active, the groundwater elevation in this well has been steadily decreasing throughout its monitoring history at a rate of approximately 1.6 feet per year. Based upon a projection of the declining trend in water levels, Well MW-22 is expected to become dry by late 2014. 3.2 Zones of Higher Conductivity and Moisture Analysis Boring logs for the Title 27 monitoring wells are presented in Appendix A. Zones of moisture (and/or zones of higher hydraulic conductivity) were noted above the intermediate zone in the borehole logs. However, the licensed geotechnical firm supervising the well installation did not consider these zones suitable for installation of a monitoring well. An evaluation of cross sections and moisture conditions is presented to evaluate the potential for the requirement for additional wells to be installed above the intermediate zone. Table 1 presents a log of all Page 6 Work Plan for Improved Detection Monitoring Program Musco Family Olive Company, Tracy, California a�,mupWnnjnMWOIUWmu mlwMBmpp*%tti 2idmpOfdaumpmlreport text-09-26.doc