During the 1800s, Catskill and Adirondack deforestation had created massive siltation of New York City harbor and imperiled shipping up the Hudson River. In 1855 New York became one of the first states to create constitutionally-designated "Forever Wild" preserves to prevent environmental and economic harms, to create a desperately needed water supply for New York City. In 1947, the people of New York passed a constitutional amendment by referendum to allow an intensive use ski center within this protected forever wild region.