America's Water Risk: Water Stress and Climate Variability

With the support of Veolia Water, this study was conducted by Columbia University’s Water Center, examining the nation's water supply, and how climate could affect vulnerability to short and long term droughts.

By utilizing a new water research metric called the Normalized Deficit Cumulated (NDC) index in the study, Columbia was able to estimate measures of water risk to the nation’s major cities and agricultural regions. Columbia developed the NDC as a risk metric for evaluating historical periods of drought, using more than 60 years of precipitation and the current water use pattern for U.S. counties. As a result, the NDC measurement tool reveals a more accurate depiction of the discrepancy between water use and water availability.

The risk indices described are computed for each of the 3111 counties in the continental U.S. using 61 years of daily climate records and the most recent national statistics that inform the current water use attributes for Agriculture, Industrial, Mining, Aquaculture, Livestock, Domestic and Thermoelectric water withdrawals. From this analysis, a map that describes the regions susceptible to persistent drought resulting from natural variations in climate and existing demand was developed. This map of NDC can help identify regions with significant multi-year climate induced water stress.

The U.S. metropolitan areas of Washington, D.C.; New York City; Los Angeles; and San Diego are of greatest concern, which could impact approximately 40 million Americans. Numerous counties in 46 states are also facing the same challenge of experiencing drought-induced shortages. Joining the metro areas on the list are the breadbasket regions of Nebraska, Illinois and Minnesota, which produce almost 40 percent of the nation's corn, a key ingredient in many of our foods and an essential feed source for livestock.


Publication Date: February 2013

Authors or Affiliated Users:

  • Daniel Shi
  • Naresh Devineni
  • Upmanu Lall
  • Edwin Piñero

Related Organizations:

  • Columbia University


Resource Category:

Resource Types:

  • Assessment


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