Laserfiche WebLink
HORIZON ENVIRONMENTAL INC. <br /> Specialists in Site Assessment,Remedial Testing,Design and Operation <br /> ` June 16, 2003 1_01 E C HVED <br /> Mr. Michael Infurna JUN 18 2003 <br /> San Joaquin County <br /> Environmental Health Department ENORUNMENT HEALTH <br /> 304 East Weber Avenue, Third Floor PERMIT/SERVICES <br /> Stockton, California 95202-2708 <br /> Subject: Revision to Work Plan Addendum <br /> Beacon Station No. 12474 <br /> 3440 East Main Street, Stockton, California <br /> Mr, Infurna: <br /> At the request of Ultramar Inc., Horizon Environmental Inc. (Horizon) has prepared this <br /> revision to the Preliminary Results of Additional Subsurface Investigation and Work Plan <br /> Addendum (Work Plan Addendum) dated February 26, 2003. The revision was developed <br /> as a result of a review of the Work Plan Addendum by the San Joaquin County <br /> Environmental Health Department (EHD) and conversations between the EHD and Horizon. <br /> The revisions to the Work Plan Addendum reflect EHD concerns that there is insufficient <br /> data on the stratigraphy and distribution of hydrocarbon-impacted groundwater intervals in <br /> the southern portion of the site to locate and construct the two proposed monitoring wells <br /> MW-15 and MW-16 shown on Figure 2 of the Work Plan Addendum. The proposed <br /> revisions should provide the level of data requested by the EHD to assess the extent of <br /> hydrocarbon impacts prior to well installation. <br /> Horizon proposes to further investigate the stratigraphy and distribution of hydrocarbon- <br /> impacted soil and groundwater intervals in the southern portion of the site prior to siting and <br /> installing additional groundwater monitoring wells. The investigation shall include the <br /> advancement of two additional curse-penetrometer test (CPT' ioo borings (CPT-2 and CPT- <br /> 3), advancement of multiple groundwater-sampling borings adjacent to the CPT-log borings <br /> and advancement of one soil sampling boring. Borings CPT-2 and CPT-3 shall be advanced <br /> at the locations shown on the attached Figure 2 to depths of approximately 150 feet below <br /> surface grade (bsg) or deeper depending on the stratigraphic data recovered as the boring is <br /> advanced. <br /> Groundwater sampling borings B-9 and B-10 shall be advanced adjacent to the CPT-log <br /> borings CPT-2 and CPT-3 as shown on the attached Figure 2. The actual number of <br /> groundwater sample intervals sampled shall be evaluated on the basis of the stratigraphic <br /> data obtained from the CPT logs. On the basis of boring CPT-1 stratigraphic data, coarse- <br /> grained intervals are expected near the water table at 64 to 65 feet bsg and at approximately <br /> 93 to 99 feet bsg. Additional groundwater samples may be collected from coarse-grained <br /> 5011 Golden Foothill Parkway, Suite 7 • EI Dorado Hills, CA 95762 • (916) 939-2170 • FAX (916) 939-2172 <br /> P.O, Box 5283 . Bakersfield, CA 93388 • (661) 589-8389 • FAX (661) 589-1456 <br />