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Enviro ctics <br /> 16 <br /> An Earth Systems Company <br /> The geologic framework of Orange County is complex;the bedrock beneath much of the County consists of <br /> folded, fractured, and metaigneous and igneous basement rocks. Intruded into these metamorphic rocks <br /> are lesser bodies of slightly metamorphosed or unmetamorphosed igneous rocks. <br /> Typical bedrock lithologies include granite, diorite, slate, tuff, and schist. In the southeastern corner of the <br /> County, sedimentary rocks of Triassic age occur along the western margin of a large basin (graben) <br /> downfaulted into the basement rocks. Bedrock in the County is overlain nearly everywhere by <br /> unconsolidated material termed regolith. <br /> The characteristics of bedrock and regolith and the hydrologic relation between them influence the water- <br /> supply potential and ground-water-quality characteristics of the groundwater system in the County. <br /> Based on the USGS report, there are two (2) main aquifer systems at the Site: <br /> • The unconfined regolith surficial aquifer, with a thickness of 97 feet or less6, and <br /> • The semi-confined fractured bedrock aquifer. <br /> —Casing Unsaturated <br /> Sap rohte zone <br /> flegolith Watertahle •�• a ••••••• •• <br /> Transition J0 ROM <br /> zone <br /> Saturated <br /> zone <br /> Fractured Open hole— <br /> bedrock <br /> N <br /> 6 https://pubs.usgs.gov/wri/2000/4286/wri2O004286.pdf <br /> Envirotactics, LLC Page 9 of 22 Hydrogeologic Desktop Study <br /> (732) 449-0077 Project No.6704 <br />