In recent times, there has been a downward trend in water use in the United States. It has been driven by increasingly efficient use of critical water resources in the face of persistent droughts in various parts of the country and awareness of the importance of conserving this resource.
A new report by the U.S. Geological Survey revealed that between 2010 and 2015, there was a 9% reduction in water use. Water use in 2015 reached a value of 322 billion gallons of water per day, which is the lowest level reported since 1970.
More than half of all the total water withdrawals in the United States occur in just 12 states. In order of withdrawal amounts, the leaders are California, Texas, Idaho, Florida, Arkansas, and New York. California accounts for almost 9% of the total water withdrawals in the United States, dominated by irrigation use. Texas uses about 7% of the total, predominantly for thermoelectric power generation, irrigation and public supply.
Nationwide, water withdrawn for thermoelectric power generation was the largest use at more than 40% of the total. Irrigation and public supply are the next two largest uses for water. The three together constitute 90% of total withdrawals. Over the five-year period reported, thermoelectric power withdrawals decreased by 18% and public-supply withdrawals decreased by 7%. However, freshwater withdrawals for irrigation increased by 2%.
A key element of the USGS tracking of the US water supply is the measure of consumptive water use. Consumptive use is the fraction of total water withdrawals that is unavailable for further use because it is evaporated, transpired by plants, or incorporated into a product. Thermoelectric water withdrawals for power generation only consume 3% of the total. Irrigation consumes over 60%.
Photo, posted July 10, 2011, courtesy of Joe Wolf via Flickr.