WORK PLANS - Laserfiche WebLink

Home Browse Search

Work Plan for the Former Two 20,000-Gallon USTs Location at Stockton AASF California Army National Guard 1.2 Installation Description and History 1.2.1 Stockton AASF,CSMS,FMS,and Armory are a state-owned facility operated by the CA ARNG. The post consists of administrative offices;facility engineering;classrooms;training facilities;security facilities;maintenance facilities;a gas station(previous);and several equipment, vehicle,aircraft and material storage locations/structures. 1.2.2 The AASF comprises the following: maintenance building(hangar)work bays and shop, supply areas,a latrine,and offices;a wash rack;various storage sheds;concrete pads and ramps; and a refueling area containing dispensers with three former 5,000-gallon USTs and two former 20,000-gallon USTs. 1.2.3 Two former 20,000-gallon steel tanks were located at the AASF fueling area.The 20,000- gallon tanks were placed within a cement-lined constructed pit. The tanks had approximately half of their surface area extending above the ground surface.For the purposes of this report,these two 20,000-gallon tanks will be referred to as USTs. The single-walled USTs were removed in the mid- 1990s;the USTs historically contained JP-4/8 fuels(Lance,2007). The two former 20,000-gallon USTs were replaced with one 20,000-gallon aboveground storage tank(AST)located immediately south of the two former USTs(the new AST contains JP-8 fuel). This AST is connected to the fuel island approximately 50 feet northwest of the AST. The fuel island location is also the location of an existing 15,000-gallon UST containing JP-8(see Figure 1-2). 1.2.4 Northwest/west,and adjacent to the former two 20,000-gallon USTs are the three former USTs(5,000 gallons each)that were constructed of steel and installed in the early 1950s.The former USTs were removed by Wallace-Kuhl in 1990. The former USTs were placed beneath the ground surface and resting on a 6-inch thick concrete slab. The slab remains in place and is estimated to exist at a depth of 11 feet below ground surface(bgs).The fuel dispensers were moved from the northern side of the UST location to the east side,approximately 30 feet away from the former UST area, during the expansion project completed in 1974.Aviation gasoline was stored in the former USTs until 1962,at which time the USTs were then filled with JP-4 until 1989(Versar, Inc.,2004). 1.2.5 In April 2002,a release of approximately 5 gallons of fuel occurred adjacent to and south of both of the former 5,000-and 10,000-gallon UST locations. The spill impacted approximately 20 square feet of soil. The spill was reported and excavated immediately after the occurrence. On 31 January 1990,an Unauthorized Release Form(No.90-U 11)was completed and submitted to the San Joaquin County Public Health Services,Environmental Health Department(PHS-EHD) (Versar,Inc.,2004). 1.3 Physiographic Setting Approximately 90%of the land surface within AASF is paved. Some grasses exist throughout the area due to landscaping and maintenance performed to reduce vegetation around aircraft locations. The site has been graded and modified to promote surface drainage into storm drain inlets(Figure 1-2). Catch basins collect rainwater and divert the runoff to the north through underground pipes into the adjacent airport/Stockton storm/sewer water system. The system drains approximately 1.5 miles north of the site into Little John Creek,then into French Camp Slough,and finally into the San Joaquin River(Versar,Inc.,2004). KAWprocess\00251\CA ARNG1Stockton AASF WP\FINAL\WP text.doc 2 June 2007