Land use planning provides a means for managing human developments to ensure maximum use of a limited resource base and to retain for future generations a maximum number of available alternatives. Many lands that once nourished great civilizations are today arid and uninhabitable. The long-term productivity and habitability of many lands in North America are being diminished by desertification. Groundwater and surface water supplies are being depleted and contaminated by overgrazing, intensive irrigation and cultivation, large water-diversion projects, industrialization, and urbanization. The problem of soil salinization has plagued agricultural civilizations for centuries. The protection of wetlands and sensitive coastal environments from dredging, draining, and filling is an important national concern. These areas are extremely important for wildlife, fisheries, and the integrity of land and water resources. The serious impacts associated with surface mining or reclamation vary with geographic region. In the Midwest, surface mining is destroying prime agricultural lands.