Laserfiche WebLink
10%02/2001 11 12 2094683433 FIFTH FLOOR P4G; 03 <br /> Prank's One Stop <br /> 2072 Yosemite <br /> September 6, 2001 <br /> Page 2 <br /> Additionally the labels"shallow"and`intermediate"are misnomers These labels do not ha,.e a <br /> lithologic basis, ana therefore,inaccurately suggest two distinct eater-bearng Tones The target <br /> depth of 55 to 70 feet was based on analytical results of z smglz soil szinple collected from CPT- <br /> 11, which has a concentration of 0 093 mg/kg [milligrams per l ilogram]at a depth of 75 feet bgs <br /> A discussion with Robert Kitay of Aqua Sciencc Engineers has revealed that the label <br /> "intermediate"was used to designate an area that was intermediate depth wither•,the water column <br /> that extends from around 20 feet bgs to more than 100 feet bgs It%vas not meant to designate a <br /> distinct water hearing stratum_" <br /> A revised SCM for this site should includes the following information <br /> • The site consists of fine grained, lower permeability sediments to a depth of about 35 <br /> feet The sediments are saturated at a depth of about 15 feet bgs <br /> • A relatively thick sand and gravel unit occurs at around 35 feet bgs and extends to 60 or <br /> 70 feet bgs This sand and gravel unit appears to be laterally extensive across the site <br /> The MtBE plume is probably present in this unit,but at concentrations of an order of <br /> magnitude less than concentrations in the fine grained sediments <br /> Under the subheading, "Additional Assessment to the North,"ASE recommends the installation of <br /> shallow(19 feet bgs)and rrud-zone(50 feet:bgs)monitoring wells,again ignoring the sand unit that is <br /> approximately 30 to 60 feet bgs PHS/EffD approves the installation of the groundwater monitoring <br /> wells providing you understand that the absence of monitoring wells in the thick sand unit that occurs <br /> approximately 30 to 60 feet bgs must be addressed at some time in the future <br /> If you have any questions,please call Dot Lofstrom at(209)465-3436 <br /> Donna Henan,Director <br /> Environmental Health Services <br /> Dot Lofstrom,RG <br /> LOP/Site mitigation unit <br /> cc Marty Hartzell, CVRWQCB <br /> Don Thompson, Thompson Consultations <br /> Robert Kitay,Aqua Science Engineers <br />