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• CONE PENETRATION TEST BORING INVESTIGATION 1..0 INTRODUCTION Condor Earth Technologies, Inc (Condor) performed a Phase II Environmental Site Assessment at the request of the City of Stockton, Department of Housing and Redevelopment (DHR) for the properties (site) comprising the six-block area bounded by E Miner Avenue to the north, N Stanislaus Street to the west, E Weber Avenue to the south, and the Southern Pacific Railroad tracks to the east in the city of Stockton, California CPT borings were installed around the site in the public right-of-way to obtain lithologic information regarding the site, especially aquifers and aquitards The Phase U ESA fieldwork was performed between May 13 and September 16, 2002 Figures referenced in this section are located in Appendix A of Condor's Phase If Environmental Site Assessment Report, Multi-Modal Station "Six-Block Project" Stockton, San Joaquin County, California dated January 6, 2003 The CPT logs and pore pressure dissipation tests (PPDTs) are included in the Presentation of Cone Penetration Test Data report prepared by Gregg 2.0 GENERALIZED GEOLOGIC SETTING The site is located in the middle of the San Joaquin Valley in the Great Valley Geomorphic Province The Great Valley Geomorphic Province is a northwest-trending, westward-dipping geosyncline that has been filled with up to six vertical miles of lithified marine and non-marine sediments, and unlithified non- marine sediments Geologic conditions at depth are relatively well known as a result of exploratory and production drilling for the nearby French Camp, Lathrop, and Stockton natural gas fields According to published geologic maps, surface deposits underlying the site consist of eolian sands . belonging to the upper member of the Modesto Formation These sand deposits are estimated to be more than 9,000 years old and are underlain by more than 3,000 feet of Cenozoic alluvial sediment primarily consisting of Pliocene and Miocene sands and clays Regionally, the upper 3,000 feet of Great Valley alluvial sediments are resultant of erosion of the Sierra Nevada granitic basement rocks to the east and, to a lesser degree, the Coast Range marine and non-marine sediments and Franciscan Assemblage and granitic basement rocks to the west The unconsolidated Cenozoic alluvial sedimentary deposits are unconformably underlain by an estimated 9,000 to 10,000 feet of Upper Cretaceous marine sands and shales belonging to the Great Valley Sequence The Upper Cretaceous sand units of the Great Valley Sequence are the primary natural gas bearing units of the local natural gas fields The Cretaceous deposits are underlain by basement rock belonging to the Franciscan Assemblage or the Sierra Nevada Granitics and Metamorphics Previous work performed by Condor in the vicinity of the site and subsequently confirmed by drilling at the site indicates that the soils of downtown Stockton are predominantly clays, sandy clays, and silty clays, especially near the surface Groundwater monitoring activities at nearby properties indicate the general groundwater gradient in the vicinity of the site is to the east, with the gradient at individual sites ranging from the northeast to the southeast The site may receive groundwater flow from properties to the northwest, west, and southwest Addresses that appeared during the government database search are listed in Table 8 with their approximate distance from the site and their gradient position with respect to the site The site does not appear to receive significant runoff from other properties Drainage from the site and adjacent properties appears to flow to the adjacent streets where it is conveyed to the city storm drainage system • i