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Laboratory assessment of alternative stream velocity measurement methods

September 6, 2019

Understanding streamflow in montane watersheds on regional scales is often incomplete due to a lack of data for small-order streams that link precipitation and snowmelt processes to main stem discharge. This data deficiency is attributed to the prohibitive cost of conventional streamflow measurement methods and the remote location of many small streams. Expedient and low-cost streamflow measurement methods used by resource professionals or citizen scientists can provide scientifically useful solutions to this data deficiency. To this end, four current velocity measurement methods were evaluated in a laboratory flume: the surface float, rising body, velocity head rod, and rising air bubble methods. The methods were tested under a range of stream velocities, cross-sectional depths, and streambed substrates. The resulting measurements provide estimates of precision and bias of each method, as well as method-specific insight and calibration formulas. The velocity head rod and surface float methods were the easiest methods to use, providing greater precision at large (>=0.6 m/s) and small (<0.6 m/s) velocities, respectively. However, the reliance on a velocity ratio for each of these methods can generate inaccuracy in their results. The rising body method is more challenging to execute and of lower precision than the former two methods but provides low bias measurements. The rising air bubble method has a complex instrument assembly that is considered impractical for potential field user groups.

Publication Year 2019
Title Laboratory assessment of alternative stream velocity measurement methods
DOI 10.1371/journal.pone.0222263
Authors Stephen Hundt, Kyle W. Blasch
Publication Type Article
Publication Subtype Journal Article
Series Title PLoS ONE
Index ID 70205245
Record Source USGS Publications Warehouse
USGS Organization Idaho Water Science Center