10179096_2103 S. GRAND - Plan (2)

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Former Circuit One 2103 S. Grand Avenue, Santa Ana, California Proiect No. 11-0106 Research, Inc. (GRI 1992). The Site at 2103 S. Grand has been vacant since abandonment by Circuit One in early 1990. There was a clarifier in suite 2103 that was used by Circuit One. The former location of the clarifier is shown on Figures 5 through 8. In the late 1980s, it was discovered that the condition of the clarifier had deteriorated (GRI 1992). It is believed that VOCs and copper entered the subsurface from this clarifier. Shallow copper contaminated soil was also found by RS in the southeastern portion of the Site in May 2012 and it is believed to be from the use of the area for storage (RS 2012B). The clarifier was removed in the early part of the project and reportedly some remedial excavation was conducted in the vicinity of the clarifier to remove some of the impacted soil. 2.3 Site Geology and Hydrogeology The following subsections describe the topography, geology, soil type, hydrologic setting and hydrogeologic setting of the study area. 2.3.1 Topography At the time of this study, the average elevation at Industrial Plaza ranged from approximately 65 feet above mean sea level (amsl) in the southwest to 68 feet amsl in the northeast (United States Department of Interior Geological Survey 1965). The topography in Industrial Plaza slopes very gently from the northeast to the southwest. 2.3.2 Geology and Soil Type The Site is located in the Santa Ana Valley-Capistrano Valley Province (California Department of Conservation Division of Mines and Geology 1976). The lowland strip separating the coastal hills from the Santa Ana Mountains includes the flood plain of the Santa Ana River in the northern segment and the Capistrano Valley in the southern segment. This area is comprised of a homoclinal sequence of mostly westerly-dipping rocks ranging in age from the Jurassic basement rocks on crest of the range Cretaceous and Tertiary formations exposed where the Santa Ana Mountains merge with the San Joaquin Hills. Lithologic features of soil in the general area are described as clayey sand with silty sand, sand, sandy silt and sandy clay strata (California Department of Conservation Division of Mines and Geology 1976). Locally, the Site lithology consists of fine grained soils that are mainly lean clay and silt inter-bedded with sandy soils that are mostly silty sand. 2.3.3 Hydrologic Settings The site is located within the Santa Ana River Basin (CRWQCB 1995). The boundary between the Los Angeles and Santa Ana Regions is the Los Angeles County line. Since the county line only approximates the hydrologic divide, part of the Pomona area drains into the Santa Ana Region, and, in Orange County, part of La Habra drains into the Los Angeles Region. The east- west alignment of the crest of the San Gabriel and San Bernardino Mountains separates the Santa Ana River basin from the Mojave Desert, which is part of the Lahontan Basin. In the south, the regional boundary divides the Santa Margarita River drainage area from that of the San Jacinto River, which normally terminates in Lake Elsinore. Near Corona, the Santa Ana River has cut through the Santa Ana Mountains and flows down onto the Orange County Coastal Plain. The Pacific Ocean Coast of the Santa Ana Region extends from just north of Laguna Beach up to Seal Beach and the Los Angeles County line. Other features of the coast include Newport Bay, Anaheim Bay-Huntington Harbor, and the major coastal wetlands areas associated with those bays. REMEDIATION SCIENCES 2