“This update to the National Water Census—the first since 1978—will give the nation critical new information about the availability and use of America’s freshwater resources,” said Salazar. “Development of the new state-of-the-art National Water Census forms a vital component of the Department of the Interior’s overall strategy to help ensure sustainable water resources for the United States. Similar to the need for the U.S. population census to make informed societal decisions, resource managers need the water census to support wise policy and decision-making on water matters.”
As competition for water grows—for irrigation of crops, for use by cities and communities, for energy production, and for the environment—the need for the National Water Census and related information and tools to aid water resource managers also grows. The Water Census will assist water and resource managers in understanding and quantifying water supply and demand, and will support more sustainable management of water resources.
“It’s true in other fields and no less so for water: you can’t manage what you don’t measure,” said Anne Castle, Interior’s Assistant Secretary for Water and Science. “The Water Census will quantify water supply and demand consistently across the entire country, fill in gaps in existing data, and make that information available to anyone who needs it—and that represents a huge step forward on the path toward water sustainability.”
The report released today describes the “water budget” approach being taken to assess water availability for the nation. Water budgets account for the inputs to, outputs from, and changes in the amount of water in the various components of the water cycle. They are the hydrologic equivalent of the deposits to, withdrawals from, and changes in the balance in a checking account and provide the hydrologic foundation for analysis of water availability.
USGS is initially focusing production of the Water Census on areas with significant competition for water availability and existing or emerging conflicts over water supply, such as the Delaware, Colorado, and Apalachicola-Chattahoochee-Flint River Basins. Increasing populations, more volatile stream flows, energy development and municipal demands, and the uncertain effects of a changing climate amplify the need for an improved understanding of water use and water availability in these crucial watersheds. The Water Census (like our national population Census) is an ongoing effort that will provide information for current and future decision makers. USGS will continually be updating it, adding to it, and improving the accuracy of the various water budget components.
The Water Census is a component of the Department of the Interior’s WaterSMART initiative (Sustain and Manage America’s Resources for Tomorrow), and fulfills a requirement under the Secure Water Act, part of the Omnibus Public Lands Management Act of 2009. Through WaterSMART, the Department is working to secure and stretch water supplies for use by existing and future generations to benefit people, the economy, and the environment, and to identify adaptive measures needed to address climate change and future demands. The report, Progress Toward Establishing a National Assessment of Water Availability and Use, is available at:http://pubs.usgs.gov/circular/1384.