ARCHIVED REPORTS_XR0011716 - Laserfiche WebLink

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USGS topograhac sheet, shows the location of the property in relation to the regional setting., SOIL TYPES AND DESCRIPTION: Surface soils an the area consist primarily of San Joaqun Loam, which as reddish-brown , slightly acidic, with good surface drainage but poor subsurface drainage. Subsoils are usually hardpan, which are underlain by unconsolidated material . The storae index of the San Joaquin loam as 12, indicative of very poor quality soil . For more detail , refer to plate III as taken from the June 1952 soils report published by the University of California. DEPTH TO GROUNDWATER & LOCATION OF WELLS: According to the Sprang 1986 water table map issued by the County Flood Control Distract, (Plate IV, ) groundwater at this location was as high as -10 'below sea level , or 77 ' bgl . Groundwater gradient as to the north-northeast, in the direction of the domestic water well on the property. This well was drilled in 1969 to a depth of 222' , with 101, casing set at 140 feet. It is located about 95 feet down gradient from the site of the UST; the first sand body was logged from 76 ' to 96 ' , interbedded sands and clays were encountered from 101 ' to bottom. No information as available on • slot size or open intervals. Refer to Plate V for the location of wells used an constructing the water level maps. PRIOR HISTORY OF SITEt In 1946, a 300 gallon UST was installed by the owner for fueling farm equipment & personal vehicles. It originally contained leaded gasoline and later unleaded fuel _ It was taken out of service an 1966 and replaced with an above ground fuel tank, which as stall an use. No records are available on fuel usage, and no attempt was made at inventory reconciliation; therefore, at as not possible to estimate the amount of leakage that may have occurred. DETAILS OF UST REMOVAL: On July 17, 1991 , Jam Thorpe 011 , Inc. removed the UST, which was in very poor condition. A slight Petroleum odor was noted during excavation. 2 soil samples were collected by Weston Laboratories personel from a depth of about 8 feet beneath the tank; samples were transported to the lab under proper chain of custody. The excavation was filled in with the removed spoil pending laboratory results. The samples were analyzed for STEX, EDS, TPH-G, total lead & soluble lead. Table I summarizes the results, which revealed significant levels of all tested substances except lead_ Exhibit F includes copies of the laboratory report and the chain of custody. DETAILS OF FIRST EXCAVATION: As a result of the lab results, a . workplan to reexcavate and resample was submitted by Thorpe pal on August 19, 1991 . It was proposed to remove approximately 300 2