ARCHIVED REPORTS XR0009914 - Laserfiche WebLink

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Groundwater Quality Monitoring - 152 East 11th Street, Tracy Page 3 Directly north of the subject property (i e 152 East 11th Street), and across 11th Street, there is a Beacon station located at 153 East 11th Street The station ;s owned by Ultramar Inc (Ultramar) of Hanford, California In connection with investigations of a release of hydrocarbon fuels at the Beacon station, a total of nine ground water monitoring wells have been installed on and around that property The SJCPHS has assigned the Ultramar property Site Code 1389 The locations of the monitoring wells that have been installed for the subject site at 152 East 11 th Street that is owned by the Navarras, for the site of Ultramar Inc 's Beacon Station at 153 East 11th Street and in surrounding areas are shown on Figure 2 Wells installed for the Navarras are designated NAV and those installed for Ultramar are designated ULT GROUNDWATER QUALITY MONITORING A program of regular groundwater quality monitoring has been established for the subject site according to the Qroundwater Sampling Plan - Property at 152 East 11th. StrQQt Tracy, California (Ref 7) which has been approved by the SJCPHS The first round of groundwater sampling conducted according to the plan was performed on July 8th , 1993 and included analysis of samples from all of the wells in both the Navarra and Ultramar arrays The results of that comprehensive program of groundwater sampling and analysis were presented in the report titled Extended Investigation of Groundwater Quality - Property at 152-East 11th. Street, Tracy, California, that was submitted to the SJCPHS on July 26th 1993 (Ref 6) As called for by the approved sampling plan, samples of groundwater from selected wells installed for the 152 East 11th Street site were subsequently recovered in October 1993 (Ref 5) and September 1994 (Ref 1) during the regional dry season and in February 1994 (Ref 3), during the wet season, to monitor seasonal changes in groundwater quality The data reported herein are from a sampling round conducted in February 17th , 1995 during the second wet season following implementation of the program of regular seasonal groundwater quality monitoring established by the groundwater sampling plan Well Purging and Sampling Procedures To initiate the February 17th , 1995 sampling program, the depth to groundwater in each of the Navarra monitoring wells (NAV-1 through NAV-8) was measured using a conductivity probe These depth are recorded in Table 1 which also gives the water table elevations computed relative to a local datum established on the top of the casing of Well ULT-7 (Note For convenience of reference, all depth-to-groundwater data that has been obtained during successive sampling rounds conducted for the wells installed for both the 152 and 153 East 11 th Street properties, since the well heads of all wells in the array were I