Using remotely sensed data to estimate river characteristics including water-surface velocity and discharge
This paper describes a project combining field studies and analyses directed at providing an assessment of the accuracy of remotely sensed methods for determining river characteristics such as velocity and discharge. In particular, we describe a remote sensing method for surface velocities using mid-wave thermal camera videography combined with image analysis. One of the critical problems in this work is determining a method for relating remotely measured water-surface velocities to vertically averaged velocities through a velocity index. We explore three similarity profiles that allow a relationship between surface and vertically averaged velocity to be found either using empirical results or simple roughness-to-depth ratios. To test the approaches we compare them in a situation where vertical structure is known over most of the flow depth through ADCP measurements. By determining best-fit profiles through the ADCP profiles, average values of the velocity index are found for the cross-sections where measurement were made. By comparing these to the predicted velocity indices from the three similarity profiles, we find that, although the differences between the various similarity profiles are substantial, they are smaller than differences associated with local nonuniformity and nonhydrostatic flow. Nevertheless, the velocity indices are accurate to about +/-5%, meaning that remotely sensed vertically averaged velocities can be computed to well within the current accuracy standard for such values when used for river gaging.
Citation Information
Publication Year | 2017 |
---|---|
Title | Using remotely sensed data to estimate river characteristics including water-surface velocity and discharge |
Authors | Jonathan M. Nelson, Paul J. Kinzel, Carl J. Legleiter, Richard R. McDonald, Brandon Overstreet, Jeffrey S. Conaway |
Publication Type | Conference Paper |
Publication Subtype | Conference Paper |
Index ID | 70192872 |
Record Source | USGS Publications Warehouse |
USGS Organization | National Research Program - Central Branch |
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Upper Midwest Water Science Center - Madison, WI, Office
1 Gifford Pinchot Drive
Madison, WI 53726
United States
Jeff Conaway
Associate Center Director for Water, Ice, and Landscape Dynamics
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Upper Midwest Water Science Center - Madison, WI, Office
1 Gifford Pinchot Drive
Madison, WI 53726
United States