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Science Applications <br /> International Corporation <br /> ® An Employee-Owned Company <br /> C20-SAI-VERNALIS-PS-01-05498 <br /> June 29, 2004 <br /> Mr. M. Scott Mansholt <br /> ChevronTexaco—Chevron Environmental Management Company <br /> P.O. Box 6012 <br /> San Ramon, California 94583-2324 <br /> Subject: Workplan for Additional Soil Borings and Installation of Monitoring Wells <br /> Vernalis Pump Station <br /> 35500 Welty Road <br /> Vernalis, San Joaquin and Stanislaus Counties, California <br /> SAIC Project Number: 06-6102-00-6369-201 <br /> Dear Mr. Mansholt: <br /> Science Applications International Corporation(SAIC) is pleased to present this scope of work to <br /> delineate petroleum-affected soil and groundwater on site and off site of the(former)Vernalis Pump <br /> Station. This scope of work is being prepared in response to the Regional Water Quality Control Board— <br /> Central Valley Region(RWQCB)letter, dated March 19,2004,requesting additional soil borings on site <br /> and off site to evaluate the lateral extent of petroleum-affected soil and groundwater. The RWQCB letter <br /> is included in Appendix A. A Site Vicinity map is attached as Figure 1 and a Proposed Boring Location <br /> map is attached as Figure 2. <br /> SITE DESCRIPTION AND HISTORY <br /> The site is located at 35500 Welty Road,Vernalis, San Joaquin and Stanislaus Counties, California <br /> (Figure 1). The site is located within the Central Valley Physiographic Province of California and has a <br /> relatively flat topography that slopes gently downward to the northeast. It is situated at an elevation of <br /> approximately 107 feet above mean sea level(MSL). The site consists of two properties: the Bellini <br /> property(formerly known as Roberts's property) and the Arcos property. The Bellini property is located <br /> in the northern part of the site and the Arcos property is located in the southern part of the site(Figure 2). <br /> The Bellini property is a triangular shaped, 5.73-acre vacant lot. The Arcos property is irregularly shaped <br /> and is currently used as a storage facility for equipment and materials. The Arcos property contains a <br /> residence and an on-site office. The site is located in a rural and light-industrial area and is bordered by <br /> Welty Road on the west,Highway 33 and Union Pacific Rail Road(UPRR)tracks on the northwest,light <br /> industrial facilities on the southeast,and agricultural areas on the south of the site. Currently,Kinder <br /> Morgan Energy Partners, L. P. (KM)maintains a high-pressure petroleum product pipeline that reportedly <br /> transports gasoline,jet fuel, and diesel, and is located along and outside of the northeastern site boundary <br /> within the UPRR right of way(ROW). According to the Environmental Site Assessment(ESA; <br /> Geological Technics, Inc., 1995),the KM product pipeline was installed approximately 4 to 5 feet below <br /> ground surface(bgs) during 1985,was constructed of 0.25-inch thick wrapped steel, and was under the <br /> control of a subsidiary of Southern Pacific Pipeline Company. <br />