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EXECUTIVE SUMMARY This Remedial Action Plan for Soil, Site 47(Site 47 RAP) was prepared to select a remedy for soil and sediment within Site 47 and adjacent areas on Rough and Ready Island(RRI) in Stockton, California(Figure 1). The remedy would be implemented to support redevelopment of Site 47 for commercial/industrial use. The purpose of Site 47 RAP is to comply with provisions of California Health and Safety Code Section 25356.1. Site 47 is located on RRI, and is owned by the Port of Stockton(Port). Figure I shows the general location of RRI, and Figure 2 shows the location of Site 47 within RRI. Site 47 is one of 52 remedial sites transferred to the Port by the United States Department of the Navy (Navy) (Figure 2). The Port prepared the Remedial Investigation/Focused Feasibility Study for Soil, Site 47(Site 47 RUFFS) (Geosyntec Consultants, Inc. [Geosyntec], 2022), which evaluated soil and sediment contamination at Site 47 and adjacent areas. The Site 47 RI/FFS also evaluated the remedial alternatives presented in this Site 47 RAP, which encompass a total area of about 83 acres. The Site 47 RUFFS briefly summarized the nature and extent of groundwater contamination, but did not evaluate remedial alternatives for groundwater. In 2016, the Department of Toxic Substances Control (DTSC) and the Central Valley Regional Water Quality Control Board (CVRWQCB) concurred that arsenic concentrations in RRI groundwater, including at Site 47, reflected background conditions. The Port is planning to conduct an additional groundwater investigation at Site 47, and an island-wide assessment of background concentrations of additional metals in groundwater. Site 47 groundwater conditions will be evaluated once these investigations are completed. Accordingly, the remedy proposed in this Site 47 RAP does not address groundwater. RRI is approximately 1,459 acres and is located within the Sacramento-San Joaquin River Delta at the confluence of the San Joaquin, Sacramento, Mokelumne, Calaveras, and Cosumnes Rivers. Formerly a riverine marshy grassland, RRI was transformed into farmland in the late 1800s with the construction of levees and implementation of a drainage system along the perimeter and throughout the interior of the island. Military use of the island started after World War I, when a United States Army camp was established. Military use ended in 2000, and the Navy transferred RRI to the Port through the United States Department of Transportation Maritime Administration in 2000, 2002, 2003, and 2011. The Port received Site 47 in 2003 and took responsibility for conducting remediation in accordance with a consent agreement(2003 Consent Agreement) between the Port, DTSC, and the CVRWQCB. Site 47 is situated in an industrial area within the southern portion of RRI (Figure 2). Site 47 contains a former model airplane landing strip and skeet/trap shooting range, abandoned buildings and sports courts, and a section of railroad tracks (Figure 3). Most of Site 47 is unpaved. Site 47 was likely part of an agricultural outlease during ownership by the Navy,but historical records do not indicate that Site 47 was used for productive agricultural purposes. Investigations conducted between 1995 and 2020 found contamination in soil and sediment. Contaminants detected within various portions of Site 47 include metals (primarily arsenic), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs). The Site 47 RAP for Soil ES-1 October 2023