3.0 Affected Environment - Knik Arm Bridge and Toll Authority

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Knik Arm Crossing DraftFinal EIS Affected Environment and explosives (OE) and soil and ground water contamination from leaking underground storage tanks, aboveground storage tanks, pesticides, and other chemical discharges. The ISA was prepared in general accordance with corridor screening guidelines as defined by the American Association of State Highway and Transportation Officials in Hazardous Waste Guide for Project Development (1990) and FHWA guidance documents on hazardous materials (FHWA 1980). Known and potential hazardous material sites in the Study Area were identified through review of federal and State databases, agency interviews, aerial photography, and site visits. Also, readily available information regarding known contaminated sites on Elmendorf was obtained from Internet databases and other information repositories. Identification of minimum search distances and the types of databases required for review were based on ASTM International’s Standard E 1527-00, “Standard Practice for Phase I Environmental Site Assessment Process” (2000). Initially, all contaminated sites listed in federal and State databases within 0.5 mile of the proposed alternatives were identified. For the purposes of investigating hazardous materials concerns, the Study Area was defined as the area within 100 feet of the outer limits of the ROW for the proposed alternatives. The Study Area has been organized into three subareas, from west to east: • the Mat-Su approach alternatives between the Burma Road intersection and the west shore of Knik Arm (includes the Point MacKenzie Road and the Northern Access Alternatives) • the two Southern Alignment bridge lengths across Knik Arm 28 • Anchorage approach alternatives (includes the Degan and Erickson Alternatives). In the ISA, the Study team rated each known and potential hazardous material location for its potential to affect the project. The Study Team rated the sites as having a high, medium, low, or negligible impact risk. High- and medium-impact risk ratings were assigned to known or potentially contaminated sites that could cause contamination of property within 100 feet of the proposed ROWs. High- and medium-impact risk-rated sites are presented below for each of the Study Area subareas. 3.5.4.1 Mat-Su approach alternatives Based on the ISA screening process, no hazardous waste or contaminated sites were located within the KAC Study Area for either the Point MacKenzie Road or Northern Access Alternatives. However, both the Point MacKenzie Road and Northern Access Alternatives would directly affect the Former Susitna Gunnery Range (FSGR). Except for approximately 1 mile at the northern terminus of the Study Area, all of the Mat-Su approach alternatives would be within the former FSGR. The 86,570-acre FSGR is located northwest of Elmendorf 28 The 14,000-foot bridge length was found to not be financially feasible and did not meet Purpose and Need criteria, however, this alternative was carried forward solely for comparative evaluation based on requests from environment resource and permitting agencies. 3-124 12/18/07
Knik Arm Crossing DraftFinal EIS Affected Environment and was used as an impact area and buffer zone for 90- and 120-millimeter antiaircraft artillery training from 1952 to 1960. The range extends as far west as the Little Susitna River and north to the town of Willow. Most of the Mat-Su portion of the Study Area is located within the firing fan (see Figure 4.19), with the exception of Point MacKenzie Road, near the Burma Road intersection. The U.S. Army Corps of Engineers (USACE) has completed an initial data archive review of the FSGR. A copy of the USACE archive report is included as Appendix B of the ISA. USACE timelines for completing assessment and potential unexploded ordnance (UXO) removal at the FSGR extend beyond 2010. OE are known to have been used within the KAC Study Area. Additionally, UXO has been verified in two of the USACE study areas, which are areas that could be affected by construction and operation of either the Point MacKenzie Road Alternative or the Northern Access Alternative. Property that would be affected by implementation of the proposed Mat-Su approach alternatives has been assigned a high-impact risk rating for OE. 3.5.4.2 Southern Alignment The Southern Alignment includes the Study Area between the bluffs, including the west and east bridge approaches, the bridge, and the Below-the-Bluff Roadway alignment along the northwest coast of Anchorage that terminates near the POA. There is no difference between the two lengths from a hazardous materials or UXO involvement perspective. The western bridge abutment on the Mat-Su side of the project would be within the FSGR OE impact area. Therefore, the issues discussed previously for the two Mat-Su build alternatives would also be applicable to the western extent of the Southern Alignment. No assessment was completed by USACE to determine the presence of UXO within Knik Arm. Therefore, the UXO risk to the in-water bridge support pilings is unknown, but this risk would be expected to be low. The Below-the-Bluff Roadway alignment would parallel Elmendorf, which is a U.S. Environmental Protection Agency (USEPA) National Priority List (NPL) site because of various environmental contamination issues related to ongoing and former military activity at the U.S. Air Force (USAF) installation. The Below-the-Bluff Roadway would come within 0.5 mile of three known Elmendorf contaminated sites (Sites LF04, WP14, and ST41, shown on Figure 4.20 and discussed in Section 4.5.4). Environmental and remediation studies by USAF have been completed at each of the three sites. 3.5.4.3 Anchorage approach alternatives 3.5.4.3.1 Degan Alternative Phase 1 The following seven paragraphs describe sites that would affect the proposed Degan Alternative for Phase 1. Preliminary Site Investigations (PSIs) are recommended (see Table 2 in the Initial Site Assessment Technical Report [KABATA 2006o]) at all seven sites to further define the potential ROW impacts for the alternative. 12/18/07 3-125
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3.0 Affected Environment - Knik Arm Bridge and Toll Authority

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