PR0535342 - Laserfiche WebLink

Home Browse Search

Page 3 Tracy Tire Fire Celeste Temple, Project Officer Formation from the upper portions of the formation, which generally contains poor water quality at a depth of 100 to 200 feet. LOCAL GEOLOGY/HYDROGEOLOGY ments, it is anticipated that the following stratigraphic Based on review of the above-referenced docu sequence would be encountered in the vicinity of the site: • silty gavels with some lenses of clayey silt to a depth of approximately•25 feet; • silts and sands with varying amounts of clay and gravel ranging from a depth of approximately 25 feet to approximately 125 feet; and • the top of the Corcoran Clay at a depth of approximately 125 to 200 feet. Itis important to note that a unit of hard silt with vaty Ila amounts of clay, s&U, and gravel commonl _` encountered at 30 to 80 feet represents the practical lint to which gravel caril'' mined. The unit is commonly referred to as a-clayLhowever, discrete samples were collected and-described by HLA at 29900 South MacArthur Rd. and by another consulting firm called RESNA at 29099 South MacArthur Rd. The soil samples were consistently logged as silts by geologists registered in the State of California, and for these reasons, the above referenced documents were used as the primary sources for constructing the stratigraphy expected near the Tracy Tire Fire site. The uppermost groundwater was logged at depths ranging from 65 to 88 feet. SITE TOPOGRAPHY The tires and the fire residues are situated below grade and contained in the bottom of a former gravel pit that varies in depth from approximately 20 to 50 feet below natural grade. Rainwater collects in the pit and infiltrates through the tires/residues into the subsurface soils. Therefore, no rainwater contacting the tires/residues exits the site as runoff. There is a north-south trending channel that is located along the eastern property boundary. The area draining into the pit is unknown. GROUNDWATER SAMPLING ANALYTICAL RESULTS As previously mentioned, groundwater samples were collected on August 14, 1998 from three wells located on properties surrounding the site. There was no well sampled on the site. A domestic well at 30010 South MacArthur Road and industrial wells at Teichert Gravel Company and at RMC Lonestar Gravel Company were sampled. On March 12, 1999, the three wells were again sampled. Additionally, groundwater was sampled at a second residence located at 8952 West Palmquist where persons living there expressed concerns regarding their water quality. The domestic wells were purged by attaching the garden hose to the faucet at the well head and watering the lawn for approximately 20 minutes. The garden hose was then removed prior to sampling. The two industrial wells at the gravel pits pump continuously, and therefore samples were collected at spigots ITTzur30.799 wpd