SR0084222 (2) - Laserfiche WebLink

Home Browse Search

Work Plan, PFAS Site Inspection Naval Computer and Telecommunications Station Stockton, California Background Information 2-9 DCN: TRBW-0202-5183-0010 activities were conducted in the area; therefore, sediment sampling of the drainage ditch and PFAS analysis was also recommended. 2.4.2.5 Site 19 - Construction Debris Stockpiles Installation Restoration (IR) Site 19 (Parcel 150) is located at the southeast corner of Humphreys Drive and Fyffe Avenue in the southwestern portion of RRI (Figure 1-2). Site 19 is an 8-acre area that was included in the Phase IV property transfer to the Port of Stockton (NAVFAC SW 2007). Site 19 is a flat, unpaved, moderately vegetated area that is occupied by nine stockpiles of soil and/or construction and pavement debris that were estimated to range in volume from 140 to 1,980 cubic yards. There is no record of any land use by the Navy at Site 19 other than the placement of these stockpiles (ERS 2016). A Preliminary Endangerment Assessment was conducted in May 2016 and concluded that benzo(a)pyrene is the only contaminant that poses a potential risk to human health at Site 19 and recommended no further investigation or action. This decision was supported by DTSC and the Water Board (ERS 2016); however, as of May 2021, the DTSC and Water Board have not yet required no further action for Site 19. This decision is pending re-issuance of a site-specific report. Based on observations of the 2019 site walk and interviews with persons knowledgeable of the site, construction debris from the Site 3 Firefighting Training Area may have been disposed of at the Site 19 soil stockpile area. As a result, the PA recommended sampling of soil, groundwater, and drainage channel sediment in the vicinity of Site 19 for PFAS analysis. 2.4.2.6 AOC 03 - Stormwater Pump House Area RRI was created in the mid- to late-1800s when farmers began constructing levees and raising the land surface with local ground filler and material dredged from nearby waterways. To protect the island from the surrounding surface waters (Burns Cutoff, the San Joaquin River, and the Stockton Deep Water Channel), a series of drainage channels were constructed to transmit groundwater and stormwater from all portions of the island to the lowest point on the island (the southwestern corner of the Landfill Area). The water is pumped off the island from the stormwater pump house located in the southwestern corner of the Landfill Area into Burns Cutoff (Figure 1-2). The depths of the drainage channels below surrounding grade range from a few feet in the central part of the island to 12 feet in the Landfill Area. Periodically, the Navy removed sediment from the drainage channels and vegetation from channel banks when sediment accumulation and vegetation interfered with flow through the drainage system. Sediment removed during dredging was deposited on channel banks. Typically, this maintenance dredging occurred every two to three years. The channels in the Landfill Area were dredged in 1994, and vegetation was partially cleared in 1997. Maintenance dredging was conducted in the Agricultural and Warehouse areas in the spring of 1998 (Tetra Tech EM Inc. [Tetra Tech EMI] 1999).