All natural resource regulation, planning, and operation are coordinated by the Department of Environmental Conservation. The state is divided into 14 soil and water conservation districts operated by local landowners with the assistance of the state Natural Resources Conservation Council. Several dams on the Winooski and Connecticut rivers' drainage basins help control flooding. Legislation enacted in 1972 bans the use of throwaway beverage containers in Vermont, in an effort to reduce roadside litter. Billboards were banned in 1968. In the 1980s and early 1990s, the effects of acid rain became a source of concern in Vermont, as in the rest of the Northeast. In 2003, Vermont had 56 hazardous waste sites listed in the Environmental Protection Agency's database, nine of which were on the National Priorities List. By some estimates as much as 35% of Vermont's wetlands have been lost since colonization. As of 2002, about 4% of the state was designated as wetlands, and the government has established the Vermont Wetlands Conservation Strategy. In 2001, Vermont received $24,854,000 in federal grants from the Environmental Protection Agency; EPA expenditures for procurement contracts in Vermont that year amounted to $87,000.