Engineering Controls
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Engineering controls, as they relate to Adak Island, include fences and signs, caps or barriers, and treatment systems. Table 3-1 summarizes engineering controls, and operations and maintenance for OU A sites.
The engineering controls identified in the OU A ROD and the OU B-1 ROD, are discussed below. Engineering controls have also been implemented for OU B-2 sites in order to protect human health until the OU B-2 ROD is finalized. Additional engineering controls may be identified in the forthcoming OU B-2 ROD.
Land Use Control and Ordnance Hazard Signs
Land use control signs and UXO hazard signs have been installed at numerous sites on Adak. The sites where signs are currently installed are included in Table D-5-1. This table also includes the type of sign and the number of signs installed at each site. Locations of the installed signs are included on Figures D-5-1 and D-5-2 for the northern and southern portions of the former military reservation, respectively. Five different warning signs have been installed on Adak: (1) warning signs at locations where notification to the Navy is required prior to excavation to depths greater than 2 feet, (2) warning signs at locations where digging is strictly prohibited, (3) warning signs at locations where trespassing is prohibited because UXO may be present, (4) warning signs at locations where mooring or landing of boats is prohibited because UXO may be present, and (5) warning signs at locations where trespassing is prohibited because of a buried landfill.
Fencing and Gates
A new steel swing gate was installed on September 20, 2006 at the entrance to Parcel 4 on the west side of Andrew Lake (U.S. Navy 2007b). The location of the new gate is shown on Figure D-5-1. New steel swing gates were installed at the main entrances to the White Alice (SWMU 18, South Sector Drum Disposal Area [White Alice Landfill] and SWMU 19, Quarry Metal Disposal Area), Roberts (SWMU 25), and Metals (SWMU 13) Landfills in 2007 (U.S. Navy 2007c). In addition, 20 feet of 4-strand barbed wire fence was installed on both sides of the installed gates to discourage drive-arounds. The fencing around the gate at the Parcel 4 boundary installed in 2006 was expanded laterally 20 feet on both sides to discourage entry by small vehicles (ATVs). Fences and gates at the access-restricted areas adjacent to Lake Andrew will be retained and maintained until the OU B-2 ROD is executed. Thereafter, ICs and engineering controls will be subject to the terms of the OU B-2 ROD.