Looking to the Future: Non-contact Methods for Measuring Streamflow

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Edited by:
T.L. Wahl, C.A. Pugh, K.A. Oberg, and T.B. Vermeyen


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We have conducted a series of proof-of-concept experiments to demonstrate whether it is possible to make completely non-contact open-channel discharge measurements. After an extensive evaluation of potential technologies, we concluded a combination of high-frequency (microwave) radar (for measuring surface velocity) and low-frequency radar (ground-penetrating radar) for measuring channel cross-section, had the best chance for success. The first experiment in 1999 on the Skagit River, Washington, using non-contact methods, produced a discharge value nearly exactly the same as from an ADCP and current meter. Surface-velocity data were converted to mean velocity based on measurements of the velocity profile (multiplied by 0.85), and radar signal speed in impure fresh water was measured to be 0.11-0.12 ft/ns. The weak link was thought to be the requirement to suspend the GPR antenna over the water, which required a bridge or cableway. Two contractors, expert with radar, were unsuccessful in field experiments to measure channel cross-section from the riverbank. Another series of experiments were designed to demonstrate whether both radar systems could be mounted on a helicopter, flown back and forth across a river, and provide data to compute flow. In Sept. 2000 and May 2001, a series of helicopter flights with mounted radar systems successfully measured surface velocity and channel cross-section of the Cowlitz River, Washington.

Additional publication details

Publication type:
Conference Paper
Publication Subtype:
Conference Paper
Looking to the Future: Non-contact Methods for Measuring Streamflow
Year Published:
Larger Work Title:
Hydraulic Measurements and Experimental Methods
First page:
Last page:
Conference Title:
Hydraulic Measurements and Experimental Methods 2002
Conference Location:
Estes Park, CO
Conference Date:
28 July 2002 through 1 August 2002