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STATE OF CALIFORNIA-Environmental Protectir;Iency . PETE WILSON Governor <br /> CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD <br /> CENTRAL VALLEY REGION „ <br /> 3443 Routier Road,Suite A O' l <br /> Sacramento,CA 95827-3098 PHONE:(916)255-3000FAX(916)255-3015 <br /> 18 February 1997 <br /> Mr. Jon Weiss <br /> Libbey-Owens-Ford Co. <br /> P. O. Box 128 <br /> Lathrop, CA 95330 <br /> ADDITIONAL GROUND WATER INVESTIGATION REPORT,PLAN,WAREROOM <br /> AREA,LIBBEY-OWENS-FORD (LOF) COMPANY, SAN JOAQUIN COUNTY <br /> I have reviewed the August 1996 Additional Groundwater Investigation Report for your facility in <br /> Lathrop, San Joaquin County. I apologize for any inconvenience the delay in submitting my <br /> comments may have caused you. My comments on the report are presented below. <br /> 1. The report states that the cullet tunnel, french drains, and west basement wall controlled <br /> the groundwater flow in the vicinity of E-1 and E-2. The cullet tunnel, french drains, and <br /> basement wall definitely affect the groundwater flow,but not necessarily control it. Due to <br /> the tight soils at the facility, groundwater flow to the french drains is limited by the hydraulic <br /> conductivity of the soils. The tunnel walls also may be acting as dams resulting in mounding <br /> near the walls. Thus, groundwater elevations at these locations may be higher than the <br /> elevations in the monitoring wells. The only way to ascertain this is to install piezometers <br /> near the walls and measure groundwater elevations in these piezometers and the monitoring <br /> wells. <br /> Figure 10 shows a flow net analysis. The equipotential and flow lines are incorrectly drawn. <br /> Groundwater should be flowing along the entire length of the french drains including the <br /> drains north(near K24) and south(near L26) of the cullet tunnel,not only in the vicinity of <br /> E-1 and E-2. <br /> Figure 9 shows cross-section A-A' looking east. However,the directional arrows of cross- <br /> section line A A' in Figure 10 shows that the viewer should be looking to the west. This <br /> discrepancy should be corrected. <br /> 2. The report states that the hydraulic fluid detected in the area of E-1 and E-2 is not of <br /> sufficient quantity to be detected in the french drains. As stated above,the groundwater flow <br /> to the french drains is limited by the hydraulic conductivity of the subsurface soils. Therefore, <br /> the french drains may not be intercepting the contaminated groundwater. <br /> 3. Based on the investigation results, LOF requests closure of the site. This request is premature <br /> because LOF has not met the conditions for low risk groundwater designation. The Tri- <br /> Regional Board Staff Recommendations for preliminary Investigation and Evaluation of <br /> Underground Tank Sites, Appendix B, No Further Action Requests(Attachment 1)provides <br />