Laserfiche WebLink
ARCADIS Mr. Roberto Cervantes <br /> September 7, 2010 <br /> Response to Comment#1 <br /> We agree that other site investigations may be required beyond those proposed in <br /> the Work Plan. The Site is an active boat maintenance and storage facility and we <br /> aim to minimize disturbance to daily activities. Geophysical investigations will be <br /> used to identify potential underground features. The geophysical data may be used <br /> to design additional investigations, which could include focused trenching, if deemed <br /> necessary. We are also researching and evaluating other sources of information, <br /> including historical aerial photographs. Please note that, as indicated in the Work <br /> Plan, the work is being performed for CEMC, which is managing this project for <br /> Texaco Inc. Thus, references should be either to CEMC or to Texaco Inc. rather than <br /> "Chevron." <br /> Comment#2 <br /> "The proposed investigation does not address the potential for contamination in <br /> deeper zones of soil and groundwater. At a nearby petroleum bulk plant site, <br /> petroleum has affected groundwater at a depth of approximately 150' below ground <br /> surface. Additional investigations will need to be performed in the deeper soils and <br /> groundwater to define the vertical extent of contamination, especially once <br /> contamination source areas are identified." <br /> Response to Comment#2 <br /> Although the proposed investigation does not include the installation of deeper <br /> groundwater monitoring wells, the proposed Laser-Induced Fluorescence (LIF) <br /> testing is not limited to shallow soil. As stated in Section 3.2 of the Work Plan, <br /> borings will be advanced "to a depth at which the LIF indicates the absence of TPH." <br /> This part of the investigation will provide valuable information on the vertical <br /> distribution of constituents of concern (COCs) at the Site. The data will be used to <br /> evaluate the potential need for additional future investigations. <br /> Comment#3 <br /> "Existing site data show that the assumed source area at the center of the site <br /> contains the highest concentrations of contaminants. The work plan proposes to <br /> install four groundwater monitoring wells around the site, none of which are in the <br /> assumed source area. A monitoring well needs to be installed in the source area so <br /> that condition of the source area groundwater can be assessed. Given the likelihood <br /> of free product in that area, the well in the source area should be constructed so as <br /> to allow for testing of free product removal from the well. For example, a 4"diameter <br /> Page: <br /> rtc-S I W P-San Jose Sc-Sep 10-80046810 doc 2/5 <br />