Skip to main content
U.S. flag

An official website of the United States government

Uncertainty in remote sensing of streams using noncontact radars

August 13, 2021

Accounting for freshwater resources and monitoring floods are vital functions for societies throughout the world. Remote-sensing methods offer great prospects to expand stream monitoring in developing countries and to smaller, headwater streams that are largely ungauged worldwide. This study evaluates the potential to estimate discharge using eight radar units that have been installed over streams in diverse hydrologic and hydraulic settings across the United States. The research highlights error characteristics associated with the measurements of stage using pulsed wave radars, mean channel velocity from continuous wave Doppler radars, and their combined use to estimate discharge at sites that were collocated with conventional streamgauges. Potential stage biases caused by the thermal expansion and contraction of supporting structures due to diurnal temperature changes were examined. A dry concrete, flume showed the temperature-dependent stage variations were no more than 2 cm. Surface velocity retrievals needed to be adjusted to represent the mean channel velocity when estimating discharge. Different approaches were evaluated and application of two different, depth-dependent adjustment factors was found to yield the most accurate estimates. This study found that it is possible to get accurate discharge estimates from noncontact radar measurements, providing cost-effective solutions for remote sensing of ungauged streams. Lastly, radar measurements of the raw variables (i.e., stage and surface velocity) can be used in an early alerting context to detect flash floods in ungauged streams.

Citation Information

Publication Year 2021
Title Uncertainty in remote sensing of streams using noncontact radars
DOI 10.1016/j.jhydrol.2021.126809
Authors Mushfiqur Rahman Khan, Jonathan J Gourley, Jorge Duarte, Humberto Vergara, Daniel Wasielewski, Pierre-Alain Ayral, John Fulton
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Hydrology
Index ID 70224260
Record Source USGS Publications Warehouse
USGS Organization Colorado Water Science Center

Related Content