Monday, November 17, 2014

Water Use in America 2010

from USGS
The U.S. Geological Survey (USGS) has just released the report “Estimated use of water in the United States in 2010.” Since 1950 the USGS has collected data on water use in the U.S. every 5 years and then several years later reports the results. This is the 13th such report and allows us to see trends in total water use for the Nation, in different geographic areas, categories of use, and sources of water over time to allow us to see and manage our water use to prevent the United States from ever running out of water. 
from USGS
The big news is that water use has continued to decrease, despite population growth. In 2010 the United States used approximately 355,000 million gallons per day of water. This was a decline of 13% from 2005. Water use in America peaked in 1980 at around 425,000 million gallons a day, then fell to about 400,000 million gallons a day from 1985 to 2000 then ticked up to 410,000 million gallons a day in 2005. Now our water use has fallen back below the level in 1970! Not all the savings in water were in fresh water. About 86% of the water used each day in America is fresh water, the rest is salt water which is primarily used in power generation and industry for cooling water in coastal areas.

In the United States 45% of all water used is for thermoelectric power generation. Water used for thermoelectric power declined 20% and was the largest percent decline. A number of factors contributed to this decline in use, but was primarily due to closure of some older power plants and a decline in the use of coal fired power plants. In generating thermoelectric power water is used in steam-driven turbines. Newer power plants are more efficient in their water use than the oldest plants.

Water use for irrigation totaled about 115,000 million gallons a day or 33% percent of total water used and 38% percent of the freshwater used. Irrigation water use (all freshwater) declined 9% from 2005. Sprinkler and micro-irrigation systems, more efficient than historic surface-irrigation methods, were used on about 58% of the irrigated acreage nationwide in 2010 and accounted for the reduction in water use. Limitations on availability of water in the west (where most irrigation takes place) pushed the adoption of water wise irrigation techniques.

Approximately 12% of water use goes to public supply, almost 7% or 23,800 million gallons of water a day goes for domestic use, which includes indoor and outdoor residential uses, such as drinking water, sanitation, laundry, cleaning and landscape watering. Public-supply water use declined 5% between 2005 and 2010, despite a 4% increase in 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. About 14% of the U.S. population or about 44.5 million people, mostly in rural areas, are not connected to public-supply systems, and water for domestic use is self-supplied from wells or other private sources. Self-supplied domestic water use was about 3,600 million gallons a day during 2010.

Self-supplied industrial water use was an estimated 15,900 million gallons a day or about 4% of total water use. Industrial water use includes water used in manufacturing and producing commodities such as paper, chemicals, refined petroleum, wood products, primary metals and processing food. Industrial use of water has declined 12% since 2005 and the USGS attributes that decline to greater efficiencies in industrial processes, more emphasis on water reuse and recycling, and in lower industrial production due to the lingering effects of the recession in 2008.

Water use in California, Texas, Idaho, and Florida accounted for more than 25% of all fresh and saline water used in the United States in 2010. California accounted for 11% of the total nationwide water use and 10% of the total freshwater water use. More than 60% of California’s water use was for irrigation (a tremendous amount of the nation’s food is grown in California), and 17% of water use (almost entirely salt water), was for thermoelectric power. In Texas, about 45% of withdrawals were for thermoelectric power (a significant portion of the power produced in Texas is exported to neighboring states), and 28% was for irrigation. Irrigation accounted for 81% water use in Idaho, and thermoelectric power accounted for 61% water use in Florida (those orange trees don’t have to be watered in the rainy Florida climate).

No comments:

Post a Comment