Laserfiche WebLink
Metadata
Document management portal powered by Laserfiche WebLink 9 © 1998-2015 Laserfiche. All rights reserved.
02 May 2001 , <br /> AGE- <br /> NC Project No. O1 0828. <br /> Page'.2-of 6'- <br /> 2.2." <br /> '2.2." :UNDERGROUND STORAGE TANK REMOVAL <br /> An,Unauthorized•Release Report (UAR) was submitted to the PHS-EHD in 1986 fortwo 6,000- - <br /> gallon diesel USTs(Tank-No. 4 and-Tank No.'5):,which were,removed from the Site sometime prior, <br /> I to 1986: Laboratory analysis,of soil samples collected from beneath the north and south ends of the <br /> ' tank pit detected total extractable hydrocarbons at concentrations'as high as 17,600.milligrams per' <br /> kilogram;(mg/kg)..In June'1987 three additional soil samples were collected from the former Tank, <br /> F .No.4 and Tank.No. 5 excavation. Laboratory analysis of the three samples detected concentrations <br /> of total volatile petroleum hydrocarbons at concentrations.ranging from 4.2 mg/kg'to.130 mg/kg. <br /> In 1992 a AR waslfiledrwith the PHS-EHD for one 21000-gallon and one 500-gallon(Tank No. <br /> Id Tank No.2, respectively) former gasoline LTSTs. Soil samples collected from beniaath'Tank <br /> Nos. 1 and 2 did_ riot contain detectable concentrations of petroleum hydrocarbons'. On 1.7 I May,1990.- <br /> was removed and one sample le was collected-from the, <br />. .one 500-gallon waste.oil UST (Tank No. 3}" p - <br /> tank.excavation.Analytical results of the soil sample were not provided to the.PHS-EHD.Analytical <br /> rresults from previous investigations are summarized in Table 1. ; <br /> 2.3. REGIONAL'GEOLOGICSETTING <br /> The property is;"situated within the Great Valley Geomorphic Province. of California, a large, <br /> I <br /> elongate- northwest trending,; as etric,structuraltrou The Great Valley Province has been <br /> $ � g• YIn?n gh. : y . <br /> filled with thick sequences of sediment ranging in age from Jurassic to-Recent,creating,a nearly flat- <br /> lying alluvial plain,extending from the,Tehachapi Mountains in the south to-the Klamath Mountains ' <br /> r iri the north:The western and eastern boundaries of this province are-comprised of the rCalifornia <br /> `Coast Range and the Sierra Nevada; respectively. Rocks;composing the.basement'complex of the <br /> province have not been`completelydefined but are believed to be metamorphic and igneous.in origin. <br /> ' The 'northern and '"southerri, ortions 'of the 'Great ;Valle Province have been designated -the <br /> r p Y _ r <br /> Sacramenf6'and San Joaquin Valleys; respectively.,' <br /> Based on the Genefal Soil Map from the'San Joaquin County'So' Survey, published by the United <br /> States Department of-Agriculture'Soil Conservation Service in 1992, the site area is within the :< <br /> Jackson-Hallenbeck-Stockton-:(JHS) association. The JHS•soils .are located-within basins, and <br /> generally consist of moderate to poorly drained-fine textured soils. The soils are generally,derived <br /> from both ina'iie-And,non-nidrine,;.sedmient, and- are-.generally formed iii'�alluvi' derived from . <br /> mixed-rock sources. <br /> { <br /> The Modesto;Riverbank,Turlock Lake Formations and,overlying recent-alluvium are the principal <br /> ` 'source's of domestic ground water in the•13,500 square-mile San Joaquin Valley Ground Water Basin, <br /> I•', (Basin 5'=22). This basin'is drained primarily bythe San Joaquin River: The nearest surface water <br /> „ ,., rtdvanced GeoEnvironmental,Inc., . <br />