Ground-penetrating radar methods used in surface-water discharge measurements

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The U.S. Geological Survey (USGS) operates a network of about 7,000 streamflow-gaging stations that monitor open-channel water discharge at locations throughout the United States. The expense, technical difficulties, and concern for the safety of operational personnel under some field conditions have led to the search for alternate measurement methods. Ground- penetrating radar (GPR) has been used by the USGS in hydrologic, geologic, environmental, and bridge-scour studies by floating antennas on water or mounting antennas in boats. GPR methods were developed to measure and monitor remotely the cross-sectional area of rivers by suspending a 100-megahertz (MHz) radar antenna from a cableway car or bridge at four unstable streams that drained the slopes of Mount St. Helens in Washington. Based on the success of these initial efforts, an experiment was conducted in 1999 to see if a combination of complementary radar methods could be used to calculate the discharge of a river without having any of the measuring equipment in the water. The cross-sectional area of the 183- meter (m) wide Skagit River in Washington State was measured using a GPR system with a single 100-MHz antenna suspended 0.5 to 3 m above the water surface from a cableway car. A van- mounted, side-looking pulsed-Doppler (10 gigahertz) radar system was used to collect water-surface velocity data across the same section of the river. The combined radar data sets were used to calculate the river discharge and the results compared closely to the discharge measurement made by using the standard in-water measurement techniques. The depth to the river bottom, which was determined from the GPR data by using a radar velocity of 0.04 meters per nanosecond in water, was about 3 m, which was within 0.25 m of the manually measured values.

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Publication type Conference Paper
Publication Subtype Conference Paper
Title Ground-penetrating radar methods used in surface-water discharge measurements
DOI 10.1117/12.383618
Volume 4084
Year Published 2000
Language English
Publisher Society of Photo-Optical Instrumentation Engineers
Publisher location Bellingham, WA
Contributing office(s) Office of Ground Water
Description 7 p.
Larger Work Title Proceedings Volume 4084, Eighth International Conference on Ground Penetrating Radar
First page 494
Last page 500
Conference Title GPR 2000: The 8th International Conference on Ground Penetrating Radar
Conference Location Goldcoast, Australia
Conference Date May 23-26, 2000
Country United States
State Washington
Other Geospatial Mount St. Helens
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