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' LEVINE•FRICKE ' line in the exploratory trenches. This includes the trenching performed where the stained soils were first reported. The exca- vations were successful in delineating the lateral extent of floating product in the area around the pipelines. Floating product was encountered in the SP-2 , SP-3 and SP-4 trenches, a distance of approximately 360 feet. No floating product was ' detected in either of the two piezometers or the single test pit on the south side of Charter Way or in the SP-1 or SP-5 trenches (Figure 1) . tOne fuel sample each from trench SP-2, SP-3 and SP-4 was deliv- ered to Canonie Environmental Services Corporation (CESC) for ' initial fuel characterization. CESC reported that the fuel was gasoline but were unable to determine whether the product was leaded or unleaded product. Further fuel characterizations were subsequently performed by other laboratories and the results are ' described in the Laboratory Analyses section of this report. Well Installation At five trench locations, a 12-inch inner diameter PVC casing was placed in a 3/4 to 1-1/2 minus gravel envelope within the trench backfill. These wells were installed to provide monitoring loca- tions for measuring product thickness, to allow collection of additional fuel samples, and to extract fuel hydrocarbons, if necessary. ' The PVC casing extended to approximately 6 to 7 feet below grade and was hand-slotted over the lower 4 to 5 feet. The gravel was placed around the well slots as the trench was backfilled. A 1 to 2 foot thick layer of compacted soil was placed over the gravel. After completing backfilling of the trenches, each of the wells were developed by pumping using a vacuum truck to induce movement of ground water and/or floating hydrocarbons into the well. The wells were then secured with snug-fitting caps. Piezometers P-26 and P-27 were installed by Woodward-Clyde Con- sultants for the Port of Stockton. Product Thickness Measurements Floating hydrocarbon thickness measurements were taken by SPPL on March 5 and 6, 1988 using a graduated tape and hydrocarbon indi- cator paste. Floating hydrocarbons were found in wells SP-2 and SP-3. Over the 2-day measurement period, hydrocarbon thickness in SP-2 varied between 0.25 feet and 0.4 feet while hydrocarbon thickness in SP-3 varied between 0.40 feet and 0.42 feet. Moni- toring wells SP-1, SP-4, and SP-5 did not contain measurable floating hydrocarbons. ' -2-