SLEEPY HOLLOW, N.Y. Finalized plans for the General Motors site cleanup released by the New York State Department of Environmental Conservation (DEC) this week include dredging 0.8 acres of the Hudson River bottom, keeping polluted soil contained under a site cover and an environmental easement.
The dredging will extend 150 feet upstream and downstream of an outfall at the southern corner of the General Motors site. The DEC noted in its decision document that the action will take away approximately 4,400 cubic yards of contaminated soil.
The cleanup is part of General Motors' voluntary participation in the Brownfield Cleanup Program.
The 97-acre property, where General Motors assembled cars and vans until the plant closed in 1996, is poised for redevelopment. A developer has not yet been chosen, but previous plans have included upscale housing, shopping and a hotel/conference space. Nothing can be built, however, until remediation is complete.
A lawsuit filed by Tarrytown against Sleepy Hollow over the project has also not been settled. Officials in both villages are waiting for a judge to rule in the matter.
The DEC said contaminated soil will be put on a staging area in the site's west parcel to be sorted for debris and material not suited to disposal. Water generated during the dredging process will be treated and put back in the river.
Officials will fill in the dredged riverbottom with sand and other fine material so that the final elevations will be restored to previous heights. Disturbed habitats will also be restored.
The dredging process also includes cleaning a 30-foot section of a storm sewer that discharges at the outfall location and inspecting the site-wide storm sewer system.
The DEC's decision also includes keeping the existing slabs and pavement on the site as a cover until site redevelopment occurs. Future construction will include concrete and soil barriers above the polluted soil and a demarcation layer.
Officials are also placing an easement on the property to ensure that future owners comply with the cleanup and safety precautions. The easement requires owners to follow a site management plan and restricts the use of groundwater.
The DEC had previously approved a series of interim remedial measures that would take place before and during site development in July 2007. Officials have already removed about 14,900 cubic yards of grossly contaminated soil containing lead, chromium, trichloroethene and petroleum. Chemical oxidants have also been used to treat residential groundwater.
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