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<br />,:: <br /> <br />" <br /> <br />, <br /> <br />20 / OFFSTREAM USE <br /> <br />For an overview of how the 339,000 Mgal/d of freshwater withdrawn during 1990 <br />was used, the eight offs1ream categories mentioned above have been combined into five <br />major categories: public supply, domestic and commercial, irrigation and livestock, <br />industrial and mining, and thennoelectric power. The source (withdrawals), use (with- <br />drawals, deliveries), and disposition of freshwater for each category of use are <br />summarized in figure 7. The source column shows the proportion of withdrawals by <br />source and the distribution of withdrawals by water-use category. Source data indicate, <br />for example, that surface water was the source of 259,000 Mgal/d of freshwater, or 76.5 <br />percem of total freshwater withdrawals in the United States. Of the 259,000 Mgal/d of <br />surface water, 50.2 percent was withdrawn directly for thennoe1ectric power. Public <br />supply is considered a source of water and figure 7 shows the total quantity of water <br />withdrawn by public supply, the percen1age of surface and ground wa1er withdrawn, and <br />the percentage of water delivered to the other wa1er-use categories. The use column <br />shows total freshwater use for each category and the percentage each category represents <br />of total offstream water use. In addition, the use column shows the proportion of the <br />source (surface water, ground water, public supply) and disposition (consumptive use. <br />retom flow) for each category. The use data indicate, for example, that domes1ic and <br />commercial use totaled 39,100 Mgal/d, (including losses in the public-supply distribu- <br />tion system), or 11.5 percent of the Nation's total freshwater withdrawals. Of this 39,100 <br />Mgal/d, 85.2 percent was supplied by public-supply systems, and 82.7 percent was <br />returned to a surface- or ground-water source after use. The disposition column shows <br />the quantity of consumptive use and retum flow after use. The disposition data indicate <br />that of the total freshwater withdrawn, consumptive use was 94,000 Mgal/d, or 27.8 per- <br />cent, and return flow was 245,000 Mgal/d, or 72.2 percent (including 27,500 Mgal/d of <br />irrigation conveyance losses). Irrigation accounted for 84.3 percent of consumptive use' <br />and thennoelectric power accounted for 52.0 percent of return flow. <br />