Measuring streamflow using the float method
Author(s): Nicolas Zegre
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Description
In this lesson, students will learn how to measure and calculate streamflow in the field using the velocity-area method and the float method. In the velocity-area method, streamflow is determined by multiplying stream velocity, the speed of water flowing in a stream channel, by the cross-sectional area of the stream channel that the water is flowing. Velocity is measured using the float method, a simple, low tech approach where the time it takes a “float” (e.g., small orange) to travel the distance from an upstream cross-section to a downstream cross-section. Additionally, students will survey stream channel cross-sections and calculate cross-sectional area using a reel tape to measure horizontal distances across the channel and a yard stick, ruler, or stadia rod to measure stream water depth.
Learning outcomes – By the end of this activity, you will be able to
- Discern basic hydrologic and geomorphic stream characteristics important to streamflow (channel depth, channel width, and calculation of cross-sectional area).
- Measure stream channel cross-sectional area using survey
- Measure streamflow velocity using the float method
- Calculate streamflow using the velocity-area equation
Cite this work
Researchers should cite this work as follows:
- Zegre, N. (2023). Measuring streamflow using the float method. River Field Studies Network, QUBES Educational Resources. doi:10.25334/2DXT-EF12