密歇根新闻广播 美国用水越来越少,但密歇根州仍然排在第10位(在线收听) |
Water use in the U.S. has dropped to its lowest level in about 45 years. But the U.S. Geological Survey found 12 states accounted for more than 50% of the total water withdrawals in the U.S. – and Michigan ranks 10th on that list. The federal agency comes out with a report every five years on water use; its latest report runs through 2015. Cheryl Dieter is a hydrologist with the USGS. "Total withdrawals in Michigan are about 10 billion gallons a day and most of that is fresh surface water," she says. About 77% of that water is used for thermoelectric power generation, another 10% is used for public supply (i.e. city water), and other uses are for industry, irrigation, household use, mining, aquaculture, and livestock. The USGS found we used 322 billion gallons of water a day in the U.S. That's a big number, but there's a downward trend here. "We've seen about a nine percent decrease in withdrawals from 2010 to 2015 and a lot of that water use is related to a decrease in withdrawals for thermoelectric power generation and also use in California," says Dieter. "A lot of power plants used once-through cooling systems, and those are being converted to more efficient recirculating cooling system types, or the once-through cooling plants are being closed and other types of plants that are more efficient are being opened," she says. She says the drought in California explains part of the drop in household water use,and state, federal and local policies have also led to more efficiencies. She says the water we use in our homes is about one percent of all the water usedin the U.S. "For the nation, we estimate withdrawals for thermoelectric is the largest use, about 41% of the total in the U.S. Irrigation is second; 37%," she says. You can learn more about water use in the U.S. here on the USGS' interactive site. |
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