Streaming toward a wetter United States.The amount of water flowing through U.S. streams has steadily increased during this century, although without giving rise to more frequent floods, according to a new study by scientists at the U.S. Geological Survey.
"The nation is getting wetter but less extreme" in terms of stream flow, says Harry F. Lins, a USGS USGS United States Geological Survey (US Department of the Interior) hydrologist hy·drol·o·gy
The scientific study of the properties, distribution, and effects of water on the earth's surface, in the soil and underlying rocks, and in the atmosphere. in Reston, Va., who coauthored a report appearing in the Jan. 15 GEOPHYSICAL RESEARCH LETTERS Geophysical Research Letters is a publication of the American Geophysical Union. GRL is the organization's only letters journal. Since its introduction in 1974, GRL has published only short research letters, typically 3-5 pages long, which focus on a specific discipline or . "The water resources of the nation seem to be improving, but we're not paying a price."
Lins and James R. Slack, also of the USGS in Reston, analyzed records from 395 stations that gauge water flow in streams in the conterminous con·ter·mi·nous also co·ter·mi·nous
1. Having a boundary in common; contiguous: The northern border of the United States is conterminous with the southern border of Canada.
2. United States. They chose remote streams that had not been altered by dam construction or crop irrigation irrigation, in agriculture, artificial watering of the land. Although used chiefly in regions with annual rainfall of less than 20 in. (51 cm), it is also used in wetter areas to grow certain crops, e.g., rice. .
Their analysis indicates that 30 percent of these streams are now carrying more water than they did 50 years ago. Days when streams had low to normal amounts of water showed almost all the increase. Few stations showed an increasing trend in water flow during times of peak flow. The net result is that the driest times of year grew moister, but the nation did not experience an increase during the wettest periods.
These findings run counter to climate researchers' expectations. Simulations by some computerized climate models of global greenhouse warming suggest that precipitation should be getting more extreme, possibly with more frequent flooding. "We find no substantiation of that hypothesis," says Lins.
Measurements of actual precipitation, however, tell a different story than the stream data do. Last year, meteorologists Atmospheric scientists