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" H A Uniolt Ice Company- Weber Street Phase 11-Report of M"Idings Page 5 IIYDRQGEQLOGIC SETTING b. t in the City of Stockton, in the floor The Union lee, Weber Street site is 10cated with plain of the San Joaquin , broad lls site sii ifeaLurclthat trlaversescenter Centlral Californiale l for f; structural trough, a large, Y two [iiijes te several hundredi'ne. The TracytSto kion Fault Te site s tc Ets across tile tlCentral f Valley inya Stockton Fault Zon f' to Stockton 'and beyond. The fault is buried y ENE -WSW direction from Tracy Quaternary basin fill sediments and is not known to be active. E The site is underlain by fluvial deposits of the San 1oatltEi�l River of Holocene (geolog- et been ically recent) Age. The Thesubsurface surface of to sitelissef 61 ssentiallyoflat,red tave ageo a tfelovationeis during this program. precipitation annually, k = about 10 feet AMSL. The site receives about 20 inches o mostly in the form of rain and nlustly in the fall an winter months. acLerized as � d h sand/ The stratigraphy of the site is char tile at Hydrogeolo cSection gravel units. The stratigraphs relationships are {Pla`e 2}. Log/Well D pre��nted in Appendix B. Detaileiagrams of the individual nloElitor wells constructed at the site are d lithologic descriptions of individual units can be found there. r y Y which was The .Ippu_rrnost clay/silt is a red, brown clayto silt clay (CH t CL - ML), named Cla; A; it is found from surface to a depth es about 15 edominantly brown7 feet, At a El >o t 10 foot depth, the color of this unit changes from p Y t predominantly bluish-gray This is indicative of a historically high water table at the site, the grey color indicates reducing conditions, while the brown color indicates Of 15 to 17 et. Local ntinues to { oxidizing conditions. The clay l3�rougllou� tills antthTile lit ology ofeClay A is carbonaceous fragments are dispersed typical of backswamp deposits of a large river system. This unit is underlain by a tine to 3arse feet1' lned depth.tnd ThinEtclay and siltelenses are presenhis dt is present from about 15 to about 35 as a in the lower half of the unit. This sand, which is named Sand 1, is classified o it's poorly sorted to well sorted sand to s'sltylalaysytypic sand (Sp of o erbankMor walling flood varying grain size. This type, of litholo,y typical deposits of large river systems. is a ick, fairly niform Sand 1 is underlain by �lay st thieklwhe eaxplored. it i�sa stiff clay which acontains CH). This clay is 15 to3 fe �a