美国地质调查局每5年评价和公布一次美国的用水状况。11月5日，美国地质调查局发布了2010年美国用水数据，结果显示：美国总用水量、各部门用水量继续呈下降趋势，总用水量降低到（稍早于）1970年以来的最低水平！ 有很多人担忧页岩气开采用水会大大增加用水量，从而加剧水资源紧张状况，但从美国的情况来看并不如此。美国是世界最早、最大的页岩气开采国。 2010年 页岩气 产量达到1378亿立方米,占天然气产量的22.6%, 2012年 页岩气产量 就达到了2653亿立方米,占其天然气总产量的37%; 2013年美国页岩气产量为2764亿立方米，占美国天然气总产量约40%。 据说，美国欲通过大规模廉价页岩气开采， 压低国际能源价格，来达到打击俄罗斯的目的。估计在可预计的未来，世界上没有一个国家可以达到美国如此巨大的页岩气开发规模。不过，即使在美国如此大的页岩气开发规模下，页岩气开发用水也没有改变美国用水量继续下降的趋势。 National Water-Use at Lowest Levels since before 1970 Released: 11/5/2014 9:16:23 AM Contact Information: U.S. Department of the Interior, U.S. Geological Survey Office of Communications and Publishing 12201 Sunrise Valley Dr, MS 119 Reston, VA 20192 Ethan Alpern Phone: 703-648-4406 Tweet 255 Water use across the country reached its lowest recorded level in nearly 45 years. According to a new USGS report , about 355 billion gallons of water per day (Bgal/d) were withdrawn for use in the entire United States during 2010. This represents a 13 percent reduction of water use from 2005 when about 410 Bgal/d were withdrawn and the lowest level since before 1970. “Reaching this 45-year low shows the positive trends in conservation that stem from improvements in water-use technologies and management,” said Mike Connor, deputy secretary of the Interior. “Even as the U.S. population continues to grow, people are learning to be more water conscious and do their part to help sustain the limited freshwater resources in the country.” Total water withdrawals by State and barchart showing categories by State from west to east, 2010.( Larger image ) In 2010, more than 50 percent of the total withdrawals in the United States were accounted for by 12 states in order of withdrawal amounts: California, Texas, Idaho, Florida, Illinois, North Carolina, Arkansas, Colorado, Michigan, New York, Alabama and Ohio. California accounted for 11 percent of the total withdrawals for all categories and 10 percent of total freshwater withdrawals for all categories nationwide. Texas accounted for about 7 percent of total withdrawals for all categories, predominantly for thermoelectric power, irrigation and public supply. Florida had the largest saline withdrawals, accounting for 18 percent of the total in the country, mostly saline surface-water withdrawals for thermoelectric power. Oklahoma and Texas accounted for about 70 percent of the total saline groundwater withdrawals in the United States, mostly for mining. “Since 1950, the USGS has tracked the national water-use statistics,” said Suzette Kimball, acting USGS director. “By providing data down to the county level, we are able to ensure that water resource managers across the nation have the information necessary to make strong water-use and conservation decisions.” Trends in total water withdrawals by water-use category, 1950–2010.( Larger image ) Water withdrawn for thermoelectric power was the largest use nationally, with the other leading uses being irrigation, public supply and self-supplied industrial water, respectively. Withdrawals declined in each of these categories. Collectively, all of these uses represented 94 percent of total withdrawals from 2005-2010. Thermoelectric power declined 20 percent, the largest percent decline. Irrigation withdrawals (all freshwater) declined 9 percent. Public-supply withdrawals declined 5 percent. Self-supplied industrial withdrawals declined 12 percent. A number of factors can be attributed to the 20 percent decline in thermoelectric-power withdrawals, including an increase in the number of power plants built or converted since the 1970’s that use more efficient cooling-system technologies, declines in withdrawals to protect aquatic habitat and environments, power plant closures and a decline in the use of coal to fuel power plants. Irrigation withdrawals in the United States continued to decline since 2005, and more croplands were reported as using higher-efficiency irrigation systems in 2010,” said Molly Maupin, USGS hydrologist. “Shifts toward more sprinkler and micro-irrigation systems nationally and declining withdrawals in the West have contributed to a drop in the national average application rate from 2.32 acre-feet per acre in 2005 to 2.07 acre-feet per acre in 2010. For the first time, withdrawals for public water supply declined between 2005 and 2010, despite a 4 percent increase in the nation’s total population. The number of people served by public-supply systems continued to increase and the public-supply per capita use declined to 89 gallons per day in 2010 from 100 gallons per day in 2005. Declines in industrial withdrawals can be attributed to factors such as greater efficiencies in industrial processes, more emphasis on water reuse and recycling, and the 2008 U.S. recession, resulting in lower industrial production in major water-using industries. In a separate report , USGS estimated thermoelectric-power withdrawals and consumptive use for 2010, based on linked heat- and water-budget models that integrated power plant characteristics, cooling system types and data on heat flows into and out of 1,290 power plants in the United States. These data include the first national estimates of consumptive use for thermoelectric power since 1995, and the models offer a new approach for nationally consistent estimates. In August, USGS released the 2010 water-use estimates for California in advance of the national report. The estimates showed that in 2010, Californians withdrew an estimated total of 38 Bgal/day, compared with 46 Bgal/day in 2005. Surface water withdrawals in the state were down whereas groundwater withdrawals and freshwater withdrawals were up. Most freshwater withdrawals in California are for irrigation. The USGS is the world’s largest provider of water data and the premier water research agency in the federal government.
标签: 用水量
