Not Tapped Out

U.S. cities may be less vulnerable to water scarcity than previously thought, according to a study in Water Resources Research.

With more people flocking to cities, ensuring that urban centers have enough water is crucial. Researchers often calculate a region’s water resources based on local, renewable sources such as rivers. But cities also import and store water, which sometimes isn’t taken into account.

To figure out how truly dire the problem was, the study authors assessed water availability for 225 urban areas in the United States with more than 100,000 people. The team included sources such as streams, reservoirs, lakes, and groundwater.

If the researchers looked only at local, renewable sources, 47 percent of U.S. city-dwellers appeared vulnerable to water scarcity. But if the calculation included imported and stored water, that number dropped to 17 percent.

The authors also searched for news reports of water shortages over the last few decades. The method that took storage into account did a better job of identifying vulnerable urban areas that actually suffered water scarcity, the team says.Roberta Kwok | 21 January 2013

Source: Padowski, J.C. and J.W. Jawitz. 2012. Water availability and vulnerability of 225 large cities in the United States. Water Resources Research doi: 10.1029/2012WR012335.

Image © Alexander Kirch |



  • John N. January 21, 2013 at 10:00 am

    I am only able to see the abstract here, but it seems from this brief article and the abstract that Climate Change scenarios were not a part of this study. If that is the case, it is worthless.


  • Jeremy January 23, 2013 at 7:30 am

    John N., the DOI link at the bottom will lead you to full article.


  • Heidi R January 23, 2013 at 11:22 am

    And what about the impact on the areas that cities import water from?

    I’d like to see a study of the potential and estimated costs for US cities to harvest rainwater from rooftops and store in cisterns for landscape irrigation and other nonpotable uses. That might also help with urban stormwater pollution and flooding.


  • Cool Green Morning: Wednesday, January 23 | Volved January 23, 2013 at 6:56 pm

    […] new study suggests American cities are maybe less vulnerable to water scarcity than previously thought. (Conservation […]


  • John January 25, 2013 at 5:57 am

    A major concern with US cities is the use of underground aquifers. Many of these are fossil aquifers, in that they are not being refilled and as a consequence are finite resources. This greatly increases the vulnerability of urban areas and will reach a point when some cities are in serious trouble. This study in trying to point out a positive should also heed the warning that we all know – water is going to become an increasingly scarce commodity in some places and we have better act now to minimise this.


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