Water Use in the US Less in 2005 Than in 1975
Just when you think all human activities are making the environment worse, news comes that our efforts to improve efficiency and reduce environmental impacts (0ur environmental footprint) are doing some good. According to a new U.S. Geological Survey report, the U S is using less water now than during the peak years of 1975 and 1980, despite a 30 percent population increase during the same time period.
The report shows that in 2005 Americans used 410 billion gallons per day, slightly less than in 2000. The declines are attributed to the increased use of more efficient irrigation systems and alternative technologies at power plants. Water withdrawals for public supply have increased steadily since 1950--when USGS began the series of five-year trend reports--along with the population that depends on these supplies.
Nearly half (49 percent) of the 410 billion gallons per day used by Americans was for producing electricity at thermoelectric power plants. Irrigation accounted for 31 percent and public supply 11 percent of the total. The remaining 9 percent of the water was for self-supplied industrial, livestock, aquaculture, mining and rural domestic uses.
"Because electricity generation and irrigation together accounted for a massive 80 percent of our water use in 2005, the improvements in efficiency and technology give us hope for the future," Castle said. The report also underscores the importance of recognizing the limits of the drinking water supplies on which our growing population depends. While public-supply withdrawals have continued to increase overall, per capita use has decreased in many States during recent decades.
The largest uses of fresh surface water were for power generation and irrigation, and the states with the largest fresh surface-water uses were California, Texas, Idaho and Illinois. The largest use of fresh groundwater was irrigation, and the states with the largest fresh groundwater uses were California, Texas, Nebraska and Arkansas.
The average amount of water withdrawn to produce a kilowatt-hour of electricity in the United States has decreased steadily from 1950 to 2005. This change is attributable to an increase in the number of power plants that use alternatives to once-through cooling.
The full report is available at http://pubs.usgs.gov/circ/1344.