USGS Washington Water Science Center
|U.S. Department of the Interior
U.S. Geological Survey
Release: February 13, 2003
253-428-3600, ext. 2687
253-428-3600, ext. 2635
[Note: The report can be viewed on the Web at http://pubs.water.usgs.gov/wri034022/ .]
A new faster, cost-saving system that creates digital aerial images of streams is yielding a wealth of data about salmon habitat, according to a report published today by the U.S. Geological Survey (USGS).
The system, called aerial multispectral imaging, uses equipment much like digital cameras to photograph streams from an aircraft. Because the high-tech digital images capture information across several different wavelengths of light, they can be analyzed with a computer to reveal a lot of information about the stream. Specific colors in multispectral images indicate various types of habitat.
"We can assess fish habitat in streams by analyzing the patterns in multispectral images," said Bob Black, USGS scientist and lead author of the report. "We can measure stream features such as pools, riffles, turbulent areas, large woody debris, water temperature, and other factors known to affect salmon."
Although the method has been used in scrublands, this is the first use in the heavily forested basins of the Pacific Northwest.
In testing the method over about 15.3 miles of the upper White River, scientists found that the percentage of each habitat type as classified from the aerial images was not substantially different from field measurements made on the ground. The method greatly reduces the cost of collecting such data over large areas. Collecting and analyzing the data takes only a fraction of the time of traditional, on-the-ground methods. For example, for the 15.3-mile stretch of the upper White River, a field crew would take about 80 days to collect the data that the aerial-based system could capture in 3 hours.
The report, "Characterization of Instream Hydraulic and Riparian Habitat Conditions and Stream Temperatures of the Upper White River Basin, Washington, Using Multispectral Imaging Systems," by Robert W. Black, Alan Haggland, and Greg Crosby, is published as U.S. Geological Survey Water-Resources Investigations Report 03-4022. The report can be viewed on the Web at http://pubs.water.usgs.gov/wri034022/ . Copies can be purchased from the U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225-0286, telephone 303-202-4200.
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