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2.0 SITE DESCRIPTION AND HISTORY 3.0 GEOLOGY AND HYDROGEOLOGY
<br /> 2.1 Site Description The Site is located within the San Joaquin Valley in the southern portion of the Great Valley Geomorphic
<br /> The Site consists of 8.3 acres with 86,180 square feet of single-story commercial space. The Site is located Province in central California.The San Joaquin Valley is a structural trough up to 200 miles long and 45 to
<br /> 70 miles wide.It conjoins the northem portion of the Great Valley Geomorphic Province,the Sacramento
<br /> Road
<br /> commercial and residential area of San Joaquin County. The
<br /> at the southwest comer of the intersection of North Tracy Boulevard and Clover shopping center is Currently occupied
<br /> ccupied by retail Valley,
<br /> ra
<br /> within a mixed Valley,at the confluence of the Sacr
<br /> amento and San loaquin Rivers('the Delta").The Great Valley opens to
<br /> commercial establishments including a super market restaurants, nail and hair salons, insurance and the San Francisco Bay west of this Delta.
<br /> financial outlets,an automobile parts store,and various professional services. Refer to Figure 1 for a Site The San Joaquin Valley is bounded by the Sierra Nevada to the east,the Coast Range to the west and the
<br /> i---- plan of the shopping center. Tehachapi Mountains to the south. It is a broad, fault bounded, northwest trending, asymmetric
<br /> topographic and structural trough,with axis of the valley offset nearer the western margin The topographic
<br /> 2.2 Project History slope along the axis declines gently,generally towards the north-northwest. A topographic map of the Site
<br /> The Site history has been described in the following documents: vicinity is shown on Figure 2.
<br /> • A/E Wert Consultants Phase I Environmental Site Assessment(December2004k Vlrthin the western San Joaquin Valley,the land surface generally slopes easterly to northeasterly from the
<br /> • Partner Phase I Environmental Site Assessment(December 9,2014); - base of the Coast Range,near the western boundary,towards the trough of the valley and the San Joaquin
<br /> • Partner Phase II Subsurface Investigation Report(December l9.2014); River. Small ephemeral streams drain from the Coast Range Mountains typically trending northeasterly
<br /> • Partner Additional Subsurface Investigation Report(January 27,2015); toward the trough of the valley.The natural land surface is relatively flat to slightly undulating.
<br /> • Partner Expedited Site Characterization(May 21,2015); The geologic materials that fill the San Joaquin Valley are mostly unconsolidated alluvial and lacustrine
<br /> • Partner Regulatory Agency Records Review(May 11,2015); sediments, Holocene to Jurassic in age,derived from parent materials of the Coast Range and the Sierra
<br /> • Partner Site Characterization Report(May 1,2017); Nevada. These sediments overlay older marine sediments.Continental deposits shed from the surrounding
<br /> • Partner Additional Site Characterization Report(May 16,2017);and mountains forth an alluvial wedge that thickens from the valley margins toward the axis of the structural
<br /> • Partner SVE Pilot Test Report(November 27,2017); trough.This depositional axis is below to slightly west of the series of rivers,lakes,sloughs,and marshes,
<br /> • Partner Baseline Health Risk Assessment and Sim-Specific Cleanup Goals Report(February 1,2018); which mark the current and historic axis of surface drainage in the San Joaquin Valley.
<br /> • Partner Memorandum for Expansion of the SVE System for Additional Testing(March 1,2018);
<br /> • Partner Addendum to the Memorandum for Expansion of the SVE System for Additional Testing The water-bearing geologic formations underlying the San Joaquin Valley typically comprise continental
<br /> (April 27,2018); deposits of-ate Tertiary to Quaternary age.These deposits1nclude the Tulare Formation,older alluvium,
<br /> • Partner Second Addendum to the Memorandum for Expansion of the SVE System for Additional flood basin deposits,terrace deposits,and younger alluvium.The cumulative thickness of these deposits
<br /> Testing(August 30,2018), ranges from a few hundred feet near the Coast Range foothills west of the San Joaquin Valley to about
<br /> • Partner Status Update for Expanded SVE-System and Additional Pilot Testing(July 30,2019). 3,0DD feet along the trough east of the valley.
<br /> Based on tidings advanced during the Site Characterization, the underlying subsurface is variable and
<br /> consists of brown, firm, damp clay with some fine to medium sand (CL) from the ground surface to
<br /> �^ approximately 10 feet below ground surface(bgs). This is consistent with the previous Site investigation
<br /> performed in January 2D15. At 10 feet bgs the subsurface consists predominantly of brown fine-grained
<br /> sand and silty sand(SM).
<br /> Three groundwater monitoring wells (MW-2, MW-4, and MW-5) were initially installed at the Site on
<br /> October 24 and 25,2016 to establish the direction and gradient of groundwater flow. Following surveying
<br /> of the top of casing elevations on November 15,2016,the groundwater gradient was calculated to be to
<br /> the northeast Based on this information, Partner proposed that wells MW-1 and MW/�3■be installed
<br /> Workplan for Additional Soil Vapor Investigation pARTN ER rn
<br /> Workplan for Additional Soil Vapor Investigation pA�lM\ NER
<br /> Tracy Comers Shopping Center Tracy Comers Shopping Center
<br /> 3225 North Tracy Boulevard 3225 North Tracy Boulevard
<br /> Tracy,Cal fomia 95376 Tracy California 95376
<br /> February 7,2020 Febri 7,2020
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