Assessing the Quality and Quantity of our Nation's Waters
Recent reports examine the health of the streams and rivers across the country, plus report on the progress for the National Water Census.
I was struck recently by the timing of two reports released within days of each other. One was a report to Congress on the progress of the National Water Census, which is being developed by the USGS. The other was EPA’s survey of the health of streams and rivers across the country.
On one level, I feel we should already have a pretty good handle on this information. It's such a natural thing to track and monitor. It's something we should have been doing for decades. But, of course, we haven't. To be honest, I can only imagine the difficulty of sending people out across the country to actually walk the streams and rivers and make the necessary measurements. This is a big country and that's a lot of walking.
Working on the theory that you can't manage what you don't measure, the Water Census is designed to help us understand both the quantity and quality of the water resources in the United States and identify any long term trends in water availability. One goal is to better forecast the availability of water as we move into an uncertain future.
The last national assessment of water resources was conducted in 1978. A lot has changed since then, especially when it comes to the state of the nation's aquifers. For the current assessment, Congress authorized $20 million for each of fiscal years 2009 through 2023, but the first appropriation for the program was only $4 million in FY 2011, followed by $6 million in FY 2012.
The USGS is initially focusing on areas with significant competition for water availability and with 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 all highlight the need for improved understanding of water use and water availability across the country.
For the health assessment of rivers and streams, more than 85 field crews spread out across the country during the summers of 2008 and 2009, sampling 1,924 river and stream sites. Using standardized field methods, they sampled everything from large rivers to small mountain streams. The long-term goal of the project was to determine whether our rivers and streams are getting cleaner and how we might best invest in protecting and restoring them.
This was the first full-scale national assessment of streams and rivers. An earlier study, in 2004, focused on the health of wadeable streams.
The researchers found that more than half of the nation's rivers (55 percent) were in poor condition for aquatic life, while only about 21 percent were in good condition. Of the three major climatic regions studied (Eastern Highlands, Plains and Lowlands and West), the West was in the best biological condition, with 42 percent of river and stream length in good condition, while the Plains region was in the worst condition, with only 16 percent of streams rated in good condition.
Not surprisingly, nitrogen and phosphorus were major stressors, with 27 percent of rivers and streams suffering from high levels of nitrogen and 40 percent with high levels of phosphorus. Researchers also found increased levels of bacteria and mercury, plus continued pressure from human disturbance.
The National Water Census report, Progress Toward Establishing a National Assessment of Water Availability and Use, is available at: http://pubs.usgs.gov/circular/1384. For more information on the National Rivers & Streams Assessment, visit www.epa.gov/aquaticsurveys.
|James Laughlin, Managing Editor|
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