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The FMS is located in one of four divisional areas at 8020 South Airport Way, Stockton, California,
<br />(95206). The divisional areas comprise of the Army Aviation and Support Facility (AASF), the
<br />Combined Support and Maintenance Shop (CSMS), the FMS, and the Armory. Figure 1-1 shows the
<br />' general layout of the areas and site features.
<br />1.2 Installation Description and History
<br />' 1.2.1 Stockton Army Aviation and Support Facility (AASF), CSMS, FMS, and Armory are a state
<br />owned facility operated by the CA ARNG. The post consists of administrative offices, facility
<br />engineering, classrooms, training facilities, security facilities, maintenance facilities, gas station
<br />' (previous), and several equipment, vehicle, and material storage locations/structures.
<br />1.2.2 FMS #24 comprises the following: maintenance building which is one story composed of
<br />' work bays, supply areas, a latrine, and offices; a vehicle inspection rack; various hazardous material
<br />sheds; concrete wash pad with associated holding tank; and refueling area containing two dispensers
<br />at an island with two former USTs.
<br />' 1.2.3 The two former USTs (one 5,000 gallon diesel and one 10,000 gallon gasoline) were removed
<br />in April 1996 by Seward Schreder Construction. Soil samples collected during removal and excava-
<br />tion of the USTs and associated piping indicated that releases of diesel fuel and gasoline have
<br />impacted soil up to 12,000 milligrams per kilogram (mg/kg) for TPHG and 7,100 mg/kg for TPHD.
<br />In addition, benzene, toluene, ethylbenzene, and xylenes (BTEX) contaminants were detected at
<br />' concentrations up to 6.2 mg/kg (ethylbenzene) and 580 mg/kg (total xylenes) (Versar, Inc., 2004).
<br />1.3 Physiographic Setting
<br />' Approximately 90% of the land surface within the FMS is unpaved. Some grasses, shrubs and trees
<br />exist throughout the area due to landscaping and maintenance of adjacent properties. The site has
<br />' been graded and modified to promote surface drainage into storm drain inlets (Figure I-1). Catch
<br />basins collect rainwater and divert the runoff to the north through underground pipes into the
<br />adjacent airport storm water system. The system drains approximately 1.5 miles north of the site into
<br />Little John Creek, then into French Camp Slough, and finally into the San Joaquin River (Versar,
<br />' Inc., 2004).
<br />1.4 Geology
<br />1 1.4.1 The site lies within the Sacramento Valley. The Sacramento Valley is composed of
<br />unconsolidated Quaternary sediments from alluvial and lake deposits. The Sierra Nevada Mountains
<br />' to the east are a source of the alluvium deposits as a result of erosion. Also contributing to the
<br />deposits are the Sacramento Valley Coast Ranges to the west. Both ranges consist of a wide variety
<br />of rocks and granite, which are metamorphic (ranging widely in age and composition) and
<br />' sedimentary. In addition, the Stockton Fault, which trends northeast -southwest, is located within the
<br />city limits, as well as, the Midland Fault Zone (trending north) located approximately 25 miles
<br />northwest of the site (Versar, Inc., 2004).
<br />I
<br />K:\Wprocess\00251\CA ARNG\Stockton FSP\FINAL\Stockton FSP.doc 3 August 2006
<br />0 Field Sampling Plan for the
<br />Former UST Location at Stockton FMS #24
<br />'
<br />California Army National Guard
<br />1.0 SITE DESCRIPTION
<br />1.1 Site Location
<br />The FMS is located in one of four divisional areas at 8020 South Airport Way, Stockton, California,
<br />(95206). The divisional areas comprise of the Army Aviation and Support Facility (AASF), the
<br />Combined Support and Maintenance Shop (CSMS), the FMS, and the Armory. Figure 1-1 shows the
<br />' general layout of the areas and site features.
<br />1.2 Installation Description and History
<br />' 1.2.1 Stockton Army Aviation and Support Facility (AASF), CSMS, FMS, and Armory are a state
<br />owned facility operated by the CA ARNG. The post consists of administrative offices, facility
<br />engineering, classrooms, training facilities, security facilities, maintenance facilities, gas station
<br />' (previous), and several equipment, vehicle, and material storage locations/structures.
<br />1.2.2 FMS #24 comprises the following: maintenance building which is one story composed of
<br />' work bays, supply areas, a latrine, and offices; a vehicle inspection rack; various hazardous material
<br />sheds; concrete wash pad with associated holding tank; and refueling area containing two dispensers
<br />at an island with two former USTs.
<br />' 1.2.3 The two former USTs (one 5,000 gallon diesel and one 10,000 gallon gasoline) were removed
<br />in April 1996 by Seward Schreder Construction. Soil samples collected during removal and excava-
<br />tion of the USTs and associated piping indicated that releases of diesel fuel and gasoline have
<br />impacted soil up to 12,000 milligrams per kilogram (mg/kg) for TPHG and 7,100 mg/kg for TPHD.
<br />In addition, benzene, toluene, ethylbenzene, and xylenes (BTEX) contaminants were detected at
<br />' concentrations up to 6.2 mg/kg (ethylbenzene) and 580 mg/kg (total xylenes) (Versar, Inc., 2004).
<br />1.3 Physiographic Setting
<br />' Approximately 90% of the land surface within the FMS is unpaved. Some grasses, shrubs and trees
<br />exist throughout the area due to landscaping and maintenance of adjacent properties. The site has
<br />' been graded and modified to promote surface drainage into storm drain inlets (Figure I-1). Catch
<br />basins collect rainwater and divert the runoff to the north through underground pipes into the
<br />adjacent airport storm water system. The system drains approximately 1.5 miles north of the site into
<br />Little John Creek, then into French Camp Slough, and finally into the San Joaquin River (Versar,
<br />' Inc., 2004).
<br />1.4 Geology
<br />1 1.4.1 The site lies within the Sacramento Valley. The Sacramento Valley is composed of
<br />unconsolidated Quaternary sediments from alluvial and lake deposits. The Sierra Nevada Mountains
<br />' to the east are a source of the alluvium deposits as a result of erosion. Also contributing to the
<br />deposits are the Sacramento Valley Coast Ranges to the west. Both ranges consist of a wide variety
<br />of rocks and granite, which are metamorphic (ranging widely in age and composition) and
<br />' sedimentary. In addition, the Stockton Fault, which trends northeast -southwest, is located within the
<br />city limits, as well as, the Midland Fault Zone (trending north) located approximately 25 miles
<br />northwest of the site (Versar, Inc., 2004).
<br />I
<br />K:\Wprocess\00251\CA ARNG\Stockton FSP\FINAL\Stockton FSP.doc 3 August 2006
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