3.0 Affected Environment - Knik Arm Bridge and Toll Authority

Knik Arm Crossing DraftFinal EIS
Affected Environment
acquisition, however, would result in the landowner assuming responsibility for any
contaminated soil encountered in the future. Additionally, management of any contaminated
soil encountered during construction through this site would be the responsibility of the
proposed KAC project proponent (HDR 2004). This property has been assigned a highimpact
rating because contamination has been documented on this property and because the
site would be crossed by the proposed Erickson Alternative. This site was assessed as having
a high-impact risk to the project because of known fuel contamination associated with the
site and because the proposed ROW would affect a large area of this site.
Phase 2
In Phase 2 of the proposed projected, the area that would be crossed by the Ingra-Gambell
Couplet is one of the original industrial areas in Anchorage. Implementation of the proposed
Ingra-Gambell Couplet could be affected by the following medium- and high-impact sites
described below.
Site 5 – Alaskan Real Estate Parking Lot – Medium Impact
Site 5 is located at 717 East 4th Avenue (see Figure 4.21). Soil contaminated with
tetrachloroethylene (PCE) and diesel range organics (DRO) was excavated and thermally
treated in 2004. PCE-contaminated soil and ground water remains on site, and studies are
ongoing. This site has been assigned a medium-impact rating because undefined soil and
ground water contamination remains and because the property is in the presumed upgradient
direction of the proposed controlled-access ROW (ADEC 2005a).
Site 14 – Lefever Property – 4th Avenue and Ingra Street – High Impact
Site 14 is located at 901 4th Avenue (see Figure 4.21). Ten USTs were removed from this
property in 1989. Soil and ground water contamination has been documented, and the
contaminated ground water plume extends off site. This site would be upgradient of the
proposed controlled-access ROW and has been assigned a high-impact rating because the
property is known to be contaminated (ADEC 2005b).
Within the Ship Creek area, the six sites discussed below were given high-site hazard ratings
because of contamination resulting from PCBs, fuels, heavy metals, solvents, and various
other chemicals. It is unlikely that the proposed Degan Alternative or the Erickson
Alternative would, however, directly affect these sites because the proposed elevated viaduct
structures would span the sites and the Ship Creek area. In all six cases, it is unlikely that
ROW would be acquired. Land within the Anchorage Terminal Reserve needed for viaduct
support structure piers would not likely require controlled-access ROW acquisition (i.e.,
easement, lease). Viaduct support piers should, however, be sited to avoid direct impact to
any of the sites identified. If there were no direct impacts during construction (i.e.,
excavation of soils) or acquisition of any of these properties for controlled-access ROW
purposes, then the risk to the project search corridors would be low for all six sites. All six
sites would require a PSI, and the risk to the project search corridors would increase to high
if controlled-access ROW were required or excavation were completed in the area of the six
sites. All six sites are shown on Figure 4.21.
3-128 12/18/07