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4 Environmental Analysis 4.5 Cultural Resources Specifically, Livermore Valley, followed by the San Francisco Bay, is to the west and San Joaquin Valley is to the east (Farrell and Kitchel 2022). The topography in the vicinity consists of sloping rounded hills with elevations ranging from 380 feet above mean seal level to 509 feet above mean seal level.The basin was historically drained by Mountain House Creek (2 miles north/northwest of the Project) and Patterson Run Creek (1 mile north of the Project), which drains eastward toward the San Joaquin Valley. No perennial or intermittent freshwater sources are located on or adjacent to the Project, although ephemeral streams are present. The deposits within the Project consist of Pliocene to early Pleistocene age Orinda and Oro Loma Formations of alluvial pebble conglomerate, sandstone, and claystone (within the central and eastern portions of the Project site); late Miocene age deposits of the Neroly Formation non- marine, locally pebbly (within the northwestern portion of the site); and surficial sediments of alluvial gravels at the base of the hills (Dibblee 2006). Soils within the Project site consist of the Diablo series, Calla-Carbona series, and Carbona clay loam (NRCS 2022). Prior to water diversions in the nineteenth century for agricultural use and the introduction of nonnative species, the ecoregions adjacent to the Project site (Bay Area and Central Valley basin and adjacent foothills) contained a mosaic of biological diversity (flora and avian, aquatic and terrestrial fauna) that was supported by climatic and hydrological conditions conducive to abundant resource availability and subsistence procurement by aboriginal populations (e.g., Costanoan, Miwok, Yokuts; Preston 1990). Before historic alterations to the landscape occurred, the surrounding environmental setting was characterized by vegetation communities, such as grassland prairies, upland oak-grass savannas, forest, seasonal wetlands, freshwater marshlands and sloughs, and riparian forests along rivers and drainages (Rosenthal et al. 2007). The foothills may have provided a travel corridor to these resources (Farrell and Kitchel 2022). The rolling hills of the Project site appear to have been dominated by annual and perennial native grasses and forbs, with no trees. Native interior grasslands included a variety of grasses and forbs (e.g., California brome, wild rye, lupine, fiddleneck) that would have supported a variety of fauna, such as deer, antelope, rabbits, hares, rodents, and birds (Eviner 2016). Today, the Project is within a rural, agricultural setting with a low population density. The Project site is primarily surrounded by agricultural and undeveloped lands, with limited rural residential to the north and west,the PG&E Tesla Substation to the west, and agricultural land and undeveloped land to the south and east. It is situated in a historically disturbed setting, where the natural habitat has been displaced by non-native vegetation through agricultural activities since the 1870s. Aerial imagery from 1948 depicts a residential ranch complex located immediately northwest of the Project site. Between 1993 and 2005, two residential buildings were constructed along the western Project boundary, and one modular home is located at the northern edge of the Project site,just within the Project boundary. Based on information provided by the parcel landowner, the Project area is annually grazed by cattle. The Project is surrounded by transmission line corridors, the PG&E Tesla Substation to the west, rural residential housing to the west of the Project site and north of Patterson Pass Road, and agricultural fields and wind turbines that dot the surrounding landscape. Griffith Energy Storage Project 4.5-2 Tetra Tech/SCH 2022120675 Draft Environmental Impact Report August 2023