November 11, 2009

Irrigation, livestock water use lowest since 1970s

Every five years the U.S. Geological Survey does an assessment of water use in the United States. It recently came out with its analysis of water use in 2005 (the latest figures).

In its analysis, it said that the United States used 410 billion gallons of water per day in 2005, which is down from 413 billion gallons per day in 2000. This number is the total amount of water withdrawn in the U.S. for all purposes -- residential, commercial, agricultural, industrial and power plant cooling.

You can find the USGS report here.

The report noted that water use for livestock production and irrigation were less in 2005 than 2000.

Water for irrigation was down 8 percent over that period and, at 128 billion gallons per day, was approximately equal to the amount of irrigation water used in 1970.

Water used for livestock, meanwhile, was the smallest since 1975 at 2.1 billion gallons per day. Water for livestock makes up less than 1 percent of of all freshwater withdrawals in the country.

Considering how much more grains, fruits, veggies, meat, milk and eggs are produced today, those figures are pretty amazing.

For comparison, water use for power generation stood at 201 billion gallons per day, while water for public supply was 44.2 billion gallons per day.

Dr. Peter Gleick, president of the Pacific Institute, blogged on the subject and provided some interesting perspectives of total water use per capita. After all, there are a 81 million more people in the United States today - yet total water use is lower.

An analysis by the Pacific Institute noted that:
  • Total water use in the U.S. in 2005 is lower than it was in 1975.
  • Per capita water use in the U.S. in 2005 is lower than it has been since the mid-1950s
  • U.S. water use, per person, peaked in 1975 at 1,944 gallons per person per day and has now dropped to 1,383 gallons per day.
Gleick called the new numbers are "the latest evidence for a remarkable change in U.S. water use toward more efficient use."

“The population of the U.S. has grown by more than 81 million people since 1975, but total water use has declined. As a result, our per-person water use is almost 30% lower than it was 30 years ago,” Gleick said.

“If each American still used 1,940 gallons per day, population growth would have caused the U.S. to use an additional 165 billion gallons per day. That’s equal to more than 12 new Colorado Rivers -- or enough water for everyone in California, New York, Florida, Texas, Illinois and Michigan," he said.

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