Measuring Stream Discharge and Base Flow in the Field

Calla Schmidt, University of San Francisco

Sarah R. Hall, College of the Atlantic

Becca Walker, Mt. San Antonio College


In this exercise, students will measure stream geometry and velocity in the field at multiple locations. They will use the velocity-area method to calculate discharge and use their calculations to determine if a stream reach is gaining or losing.

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Learning Goals

Content/Concept Goals:

Students will...

  • Survey channel geometry.
  • Measure stream velocity across a channel cross section.
  • Calculate stream discharge from field data using the velocity-area method.

Other Skills Goals for this Activity:

Students will...

  • Practice recording field data and using Excel.

Context for Use


This activity was completed during the 2-week summer E-STEM Field Course with ~20 undergraduate students interested in environmental science.

Prerequisite Skills and Concepts:

This activity assumes that students are already familiar with basic concepts of stream hydrology and that they have already used the velocity-area method with a sample dataset.

How the Activity is Situated in the Course:

This activity follows the Introduction to quantifying stream discharge and base flow. View the E-STEM field course timeline for more information about how this activity was situated in the field course.

Description and Teaching Materials

Student Handout

discharge_base_flow_field_handout.docx (Microsoft Word 2007 (.docx) 21kB Sep11 20)


  • Survey equipment (tape measure, stadia rod, transit, and tripod)
  • Waders
  • Flow meter for measuring stream velocity

Teaching Notes and Tips

I suggest breaking your class into groups of three students and setting up a rotation through stations for surveying, discharge measurements, and field sketching. For example, we set up two locations for discharge measurements, and two total stations, one positioned for a longitudinal survey and one positioned for channel cross sections. We had remaining groups walk a designated length of the stream making a detailed field sketch of geomorphic features. Student groups rotated through the stations to get at least one turn with surveying, discharge, and sketching. When we returned from the field students shared data to get a complete dataset.


Assess this activity with the rubric used for the Hydrology Badge.