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30 RESTORATION OF AQUATIC ECOSYSTEMS Restoration Initiative Because of the highly modified and disturbed state of many of our aquatic ecosystems, particularly those closely associated with large population centers or located in agricultural areas, there is consider- able potential for the use of restoration to solve water quality, wild- life, and flooding problems. A restoration initiative must be broad and also must encompass large tracts of land; yet these areas need not impinge on the economic viability of agricultural or urban cen- ters. For example, restoration of about 50 percent (approximately 59 million acres) of the nation's lost wetlands (117 million acres in the past 200 years) would affect less than 3 percent (Table 1.7) of the land used for agriculture, forestry, and urban settlement. ~f course, most wetland restoration would take place- on floodprone land that is uneconomical for farming or other activities. Given the 162 million acres of flood-prone land (Table 1.8) and if the nation restored 59 million acres of wetlands in the long term, only 36.4 percent of the flood-prone areas would have to be given over to wetland restora- tion. The restoration -could take .place in littoral zones around lakes and reservoirs and along the floodplain, creating circular greenways and along the floodplain creating green corridors. TABLE 1.7 Allocation of Wetland Areas (in millions of square acres) by Land Categorya Category Total Area Presettlement Wetlands Area Current State of Wetlands Existing Destroyed Agriculture 1,233 134 40 94 Forest 497 54 41 13 Parks 211 23 21 2 Tundra 189 170 170 0 Urban 74 8 2 6 Defense 24 3 1 2 Desert 21 0 0 0 Other 16 0 0 0 Total 2,265 392 275 117 aPresettlement wetlands represent 11 percent of the relevant land use cat- egory except for tundra, which was taken from Dahl (1990). SOURCES: McGinnies et al., 1968; Joint Federal-State Land Use Planning Commission for Alaska, 1973; Frey and Hexem, 1985; Bureau of the Census, 1990; Dahl, 1990.