SITE INFORMATION AND CORRESPONDENCE_FILE 1

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., Page 2, 4075 Main Street • 3. The addendum states that the screen intervals of the deep monitoring wells were "modified to their present configuration due to comments received from the County" in the work plan response letter. SJC/EHD does not agree with this statement. The comment from the county concerning the configuration of the wells was that the borings should be continuously cored over the proposed 90-110 foot screen interval to ensure interception of the suspected water-bearing zone noted at approximately 100 feet below surface grade (bsg) in boring CPT-2. Continuous coring to 110 feet was not done. Furthermore, it appears that the CPT equipment was not working properly over deeper portions of CPT-3, near the southeast corner of the intersection. As a result, the log from that boring is incomplete. Therefore, the statement by GHH that the sand zones 'pinch out' in this direction and a deep monitoring well is not justified at this location is not supported by the available data. Specifically of interest is the lack of information from the interval of 99-105 feet bsg. 4. One proposed deep, discretely screened monitoring well will be installed onsite near the former tank pit area. The boring for this well will be continuously cored from 90- 110 feet bsg to ensure proper placement of the screened interval over an appropriate water-bearing zone. SJC/EHD approves a 5-foot screen interval for this deep well, not a 10-foot screen. 5. All wells will be surveyed to an established benchmark, and all survey and analytical data will be submitted to Geotracker, the State Water Resources Control Board database program. 6. The map of this site provided by GHH is difficult to use. The map is not drawn to scale, and it incorrectly indicates that Adelbert Ave. and Gertrude Ave extend to the south of Main Street. They do not; they extend north from Main Street only. An accurately scaled map must be provided for this site, and surrounding area of interest. To summarize, the following scope of work is approved: 1. One deep, discretely screened monitoring well will be installed onsite. The boring will be continuously cored from 90-110 feet bsg to install 5 feet of screened casing over an appropriate water-bearing zone. 2. Two additional monitoring wells will be installed, one each near the MW-6 and MW-7 clusters. These borings will also be continuously cored from 90-110 feet bsg to install five feet of screened casing over an appropriate water-bearing zone. 3. Two additional clusters of wells will be installed to the east and southeast of the site. Each cluster shall consist of three monitoring wells to intercept and monitor the three potential water bearing zones noted at the current well cluster locations. The deeper wells in these clusters are approved to have 5 feet of screened casing. SJC/EHD recommends placement of one of the clusters on Annabelle Lane, the other on the north side of Main Street, half way between the MW-6 cluster and Adelbert Street. Subsurface lithological information at these proposed locations is not available. SJC/EHD recommends that either the borings at these locations be continuously cored to a minimum 110 feet bsg, to ensure placement of the well screens over appropriate water bearing zones, or that further CPT work be completed prior to their installation. 4. Following installation of these wells all monitoring wells belonging to this site must be surveyed to an established benchmark. 5. A good, accurately scaled map of the site and immediate surrounding area must be provided in all future reports. 6. All survey and analytical data will be submitted to Geotracker.