The Congress finds that it is in the public interest to preserve, restore, and improve the wetlands of the Nation, and thereby to conserve surface waters, to preserve and improve habitat for migratory waterfowl and other wildlife resources, to reduce runoff, soil and wind erosion, and contribute to flood control, to contribute to improved water quality and reduce stream sedimentation, to contribute to improved subsurface moisture, to reduce acres of new land coming into production and to retire lands now in agricultural production, to enhance the natural beauty of the landscape, and to promote comprehensive and total water management planning. The Secretary of Agriculture (hereinafter in this chapter referred to as the "Secretary") is authorized and directed to formulate and carry out a continuous program to prevent the serious loss of wetlands, and to preserve, restore, and improve such lands, which program shall begin on July 1, 1971.