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Evaluation of select velocity measurement techniques for estimating discharge in small streams across the United States

September 15, 2022

Multiple instruments and methods exist for collecting discrete streamflow measurements in small streams with low flows, defined here as less than 5.7 m3/s (200 ft3/s). Included in the available methods are low-cost approaches that are infrequently used, in part, because their uncertainty is not well known. In this work, we evaluated the accuracy and suitability of three low-cost velocity measurement methods (surface float [SF], velocity head rod [VR], and rising body [RB]) and three conventional current meters (acoustic Doppler velocimeter, and mechanical Price type AA and Price Pygmy meters) relative to discharge calculated from stable artificial hydraulic controls. A total of 231 measurements were made by 20 individuals during 88 site visits to 24 sites in eight states. Accuracies were assessed for all methods and precision was evaluated for the low-cost methods. The median percent error was below 5% for conventional methods, and below 20% for the low-cost methods. The SF was the most accurate (median absolute percent error 14%) and precise (mean percent precision of 11%) low-cost method. The RB and VR, respectively, had 15% and 20% median absolute percent error and 29% and 12% mean percent precision. Results suggest that low-cost methods, when used appropriately, can be used to estimate discharge data under low flow conditions when measurements with conventional methods are not feasible and the associated accuracies meet end-user measurement objectives.

Citation Information

Publication Year 2022
Title Evaluation of select velocity measurement techniques for estimating discharge in small streams across the United States
DOI 10.1111/1752-1688.13053
Authors Tyler Victor King, Stephen Hundt, Amy E. Simonson, Kyle Blasch
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of the American Water Resources Association
Index ID 70236689
Record Source USGS Publications Warehouse
USGS Organization Idaho Water Science Center, New York Water Science Center