4. Environmental Setting and Impacts D. CULTURAL RESOURCES Section 4.D, Cultural Resources, considers both archeological resources, tribal cultural resources, and historic architectural resources. Archeological resources are discussed first, followed by a separate discussion of historic architectural resources that begins on p. 4.D.33. ARCHEOLOGICAL RESOURCES This subsection assesses the potential for the presence of archeological resources within the project site, provides a context for evaluating the significance of archeological resources that may be encountered, evaluates the potential impacts (project and cumulative) of the Proposed Project on archeological resources, and provides mitigation measures that would avoid or reduce potential impacts on archeological resources. An independent consultant has prepared an Archeological Research Design and Treatment Plan (ARDTP) for the project site.1 The research and recommendations of the ARDTP are the basis for the information and conclusions of this EIR section with respect to archeological resources. The information in the ARDTP used in the preparation of this subsection was obtained from regional databases, plans, and reports relevant to the Proposed Project, including the San Francisco Maritime National Historical Park photographic collection; the San Francisco History Center at the San Francisco Public Library; Sanborn Fire Insurance maps;2 San Francisco newspapers; the California Digital Newspaper Collection, sponsored by the University of California, Riverside; the Online Archive of California; the Union Iron Works Historic District National Register Nomination Form; the Library of Congress; and the David Rumsey Map Collection, which also provided useful sources of online maps, including those from the U.S. Coast and Geodetic Survey, U.S. Geological Survey, and official City and County survey maps. Other relevant primary references include (but are not limited to) historic photographs and aerial images, City directories, U.S. Census data, and municipal reports. 1 ESA, Pier 70 Mixed-Use District Project, City and County of San Francisco, Archaeological Research Design and Treatment Plan, June 2015. 2 Sanborn Maps is an American publisher of maps of U.S. cities and towns. The maps were initially created to estimate fire insurance risks, and are now used as a record of roads and structures extant at the time. December 21, 2016 Pier 70 Mixed-Use District Project Case No. 2014-001272ENV 4.D.1 Draft EIR 4. Environmental Setting and Impacts D. Cultural Resources Archeological Resources ENVIRONMENTAL SETTING PREHISTORIC AND HISTORIC CONTEXTS The following discussion outlines the prehistoric context of the project site, based on relevant chronological prehistoric archeological sites on the San Francisco peninsula and in the San Francisco Bay Area. Prehistoric Context The oldest evidence of human occupation in San Francisco includes two isolated human skeletons discovered 45 years apart deep below City streets in marine deposits. In October 1969, fragmentary human bones were encountered during construction of the BART Civic Center Station in downtown San Francisco. Radiocarbon dating of associated organic material indicated the remains were nearly 5,000 years old. The skeleton was discovered 75 feet below ground surface within a 40-foot-thick clayey silt stratum (bay deposits), approximately 26 feet below mean sea level. More recently, an intact human skeleton was found during construction of the Transbay Transit Center in February 2014. The human remains were encountered at a depth of 58 feet below ground surface within a compressible marine clay known as Bay Mud deposits, and are estimated to be between 5,000 to 7,000 years old. The majority of known prehistoric sites in San Francisco are no more than 2,000 years old and were found buried at depths of approximately 10 to 20 feet below ground surface. Near the southeastern shoreline of San Francisco, most of the prehistoric sites are shell midden sites, which have their greatest known concentrations in the South of Market neighborhood (north of the project site) and the Hunters Point-Bayview-Candlestick Point-Visitacion Valley area (south of the project site). A National Register-eligible district that incorporates several prehistoric sites is within sand dunes formed along the north side of historic Mission Bay, within the South of Market neighborhood approximately 1.5 miles north of the project site. These sites are considered to represent elements of a large prehistoric multi-village community. No prehistoric archeological sites have yet been encountered on the project site. California prehistory consists of following periods: the Terminal Pleistocene period (11,500- 9,600 B.C.), characterized by small and highly mobile populations of hunter-gatherers; the Early Holocene period (9600-5700 B.C.), characterized by semi-mobile hunter-gatherers who used flaked stone tools and ground stone implements; the Middle Holocene period (5700-1800 B.C.), characterized by substantial settlements, isolated burials, distinct cemeteries, milling slabs, mortars and pestles, and the fabrication and use of shell beads and other ornaments; and the late Holocene period (1800 B.C.-A.D. 1780), characterized by establishment of large shellmounds, exploitation of deer, sea otter, mussels, and clams (by the Yelamu Ohlone tribe in the San December 21, 2016 Pier 70 Mixed-Use District Project Case No. 2014-001272ENV 4.D.2 Draft EIR 4. Environmental Setting and Impacts D. Cultural Resources Archeological Resources Francisco peninsula), and brought to a close by disruption of the Mission system, disease, and displacement with European contact. Historic Context Spanish Period (1776-1820) The historic period begins with the first European expedition into the San Francisco Bay Area in 1772 by Pedro Fages and his party. During the Spanish Period (1776-1820), the Spanish established Mission San Francisco de Asís (also known as Mission Dolores) in 1776 on land occupied seasonally by the Yelamu Ohlone. No permanent Ohlone or Spanish settlements were present in the vicinity of the project site during the Spanish Period. The Spanish missionaries used portions of what are now the Potrero Hill and Dogpatch neighborhoods, including the territory around the project site, as pasture for livestock known as Potrero Nuevo, or “new pasture.” Mexican Period (1821-1848) During the Mexican Period (1821-1848), following the ceding of Spain’s North American colonial outposts to the newly independent Republic of Mexico in 1822, Upper California became a province of the Republic of Mexico. In 1833–1834, the Mexican government secularized the Spanish missions, and many mission lands were also subsequently granted to wealthy and politically influential individuals who established vast cattle raising estates, or ranchos. During the Mexican period, Potrero Hill, including Potrero Point, became part of a large rancho known as Rancho Potrero de San Francisco, which was granted by the Mexican government to the sons of Francisco de Haro. Potrero Point is the geographical name for the eastern arm of the Potrero Hill natural landmass extending into San Francisco Bay. It includes those portions of the project site that are not on filled land, the Illinois Parcels and the southeastern area of the 28-Acre Site. The project site remained undeveloped throughout the 1840s. War between the United States and Mexico broke out in 1846. American attempts to seize control of California quickly ensued, and within two months California was taken by the United States. Skirmishes between the two sides continued until California was officially annexed to the United States on February 2, 1848. Gold Rush Period (1849-1959) The discovery of gold in the Sierra Nevada in 1848 began the Gold Rush Period (1849-1959). During this period, immigrants poured into the California territory seeking gold or associated opportunities. To accommodate the growing population, the City soon spread out in all directions. During the early Gold Rush period, the project site was located far beyond the sparsely populated southern edge of development that was concentrated to the north. The project site remained undeveloped throughout the 1850s, with the exception of a single structure in the December 21, 2016 Pier 70 Mixed-Use District Project Case No. 2014-001272ENV 4.D.3 Draft EIR 4. Environmental Setting and Impacts D. Cultural Resources Archeological Resources northern portion of the project site and a dirt track that traversed the southwestern corner. A powder magazine (a place used for artillery storage) along with several other structures and piers were present just south of the project site in 1859. In addition, the Tubbs Cordage Company’s rope-making facility, which was established in the mid-1850s and included a 1,000-foot-long rope walk, was approximately 0.25 mile south of the project site. Historic maps and charts of San Francisco indicate that at the time of the Gold Rush and in the decade following, land reclamation off Potrero Point had not yet begun, and the eastern and northern portions of the project site were within San Francisco Bay. Late Nineteenth Century (1860-1899) In the late nineteenth century, development of the project site occurred at a steady pace. Industrial complexes were established in the northern and eastern portions of the project site, and residential and commercial neighborhoods were founded on Irish Hill in the southern and western portions, as described below. INDUSTRIAL COMPLEXES Little