Tetra Tech, under contract to the New York Power Authority (NYPA), prepared an Environmental Impact Statement (EIS) for a 27-mile, 46 kV transmission line and a new 115 kV/46 kV substation in the Adirondack Park. The project was the result of a need by National Grid (formerly Niagara Mohawk) and NYPA to increase the reliability of the electric system in the Tri-Lakes Region of New York.

The draft EIS was published in November 2005 and included an analysis of impacts to soils, water quality, fish and wildlife, wetlands, threatened and endangered species, vegetation, cultural resources, land use and zoning, shoreline and designated rivers, visual character, public health and safety, air quality, ambient noise levels, and traffic and transportation. The final EIS was filed in 2006, and a findings statement was subsequently issued, accepting the mitigation measures outlined in the EIS and approving the proposed action.

While NYPA and National Grid were moving forward with the approved action, they were encouraged by members of four environmental groups to pursue a Constitutional Amendment for a route through Forest Preserve land, which would be shorter with fewer potential environmental impacts. Subsequently, Tetra Tech prepared a Supplemental EIS to evaluate three alternate alignments through Forest Preserve land along State Route 56. The Supplemental Draft Environmental Impact Statement (DEIS) was published in January 2008. The Supplemental FEIS for the preferred alternate route, known as the West Alternate, was filed and accepted as complete in March 2008.