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COUR'I'I~QUSE SQUARE <br />SUBSUIdFACE REi~iIEDIATION PRESENTATION OUTLINE <br />1) Researched historical activit~es to identify saspect areas of contamination: <br />three gasoline service stations, several automobile and battery repair <br />facilities, one known UST and several areas of suspected USTs, drywells <br />2) Conducted a pre-demolition subsur.f~rP investigation to evaluate soil and groundwater <br />contamination at known or suspect areas. This further defined the nature and extent of <br />subsurface contamination: <br />17 areas of known or suspected subsurface contamination were identified, <br />including one area of gasoline contamination (Chevron) and several areas <br />of diesel contamination resulting from historical use/storage of petroleum <br />products on site <br />3) Developed a pre-construction remediation work plan to investigate and/or remove <br />contaminated soil and groundwater from the 17 areas of known or suspected <br />contamination. One objective was to "clear° the construction phase excavation/work <br />zone (ground surface down to 12 feet) from subsurface contamination. The Oregon <br />Department of Environmental Quality (DEQ) reviewed and approved of the work plan. <br />4) Implemented the pre-construction remediation work plan between October 1997 and <br />January 1998, which included: <br />• excavation and off-site disposal of approximately 7,368 tons of petroleum <br />contaminated soil <br />• excavation and off-site disposal of approximately 6,888 cubic yards of <br />non-impacted overburden soil <br />• removal and treatment of 367,250 gallons of petroleum contaminated <br />groundwater <br />~ ~:~~ ~o~~uiiissi~r~ir.g ~iiir~~ TJSTs - f~ve dccor~missi~ned in nl~ces an~ four <br />dECOrz~:~.i~si~n~d by r~moval <br />5} ~:ssaed tl~r~~ r::;~cs-ts in Niar.ch - a~ril ? g>;~ ra~~~;;„~~r~ti~3~ ~~,i,:.e~iial ~~t~vitie~ a:~c~ <br />rP~or~:.r~.;:,nding c~~sure far t~:~ 1"I ~:t~;; c~n 3:rfe ~;~~~:~F~c~~~~ S~uaz°~ block. `~~l~e tl~.:,:e reports <br />aa~e cu~ently~ bei~1~ .~viewec~ t~y th~ ~EQ. . <br />b) ~ srr~all ~~~~k~i ti~~ c~~tariii~~ti+~;~ asse~:ated wit~. t~~e f~r~r~~r Ch:;v~an ~~,rvice ~a~tion was <br />teft in p:~cz in ¢?~e soutliea,t c~~r± ;r of the bl~c~e ~lue r~ c~:~ce,ns ~~r,r stre~: s~~il~ty. ~1sr~g <br />DRAT~"; <br />Centary West ~:rsgi?ieeri~~ - 1- Aprii 28, 1?98 <br />