Total Maximum Daily Load

Calla Schmidt, University of San Francisco

Sarah R. Hall, College of the Atlantic

Becca Walker, Mt. San Antonio College

Initial Publication Date: August 31, 2020 | Reviewed: March 12, 2023


In this exercise, students measure water quality parameters and determine if the water quality objectives of State Water Resource Control Board (SWRCB) are being met. They also determine the total load of total dissolved solids (TDS), phosphorus, and nitrogen delivered to downstream environments.

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Learning Goals

Content/Concept Goals

Students will...

  • Compare field data with SWRCB water quality objectives.
  • Practice measuring stream discharge.
  • Calculate total daily load for TDS, nitrogen, and phosphorus.

Higher Order Thinking Skills Goals

Other Skills Goals for this Activity

Students will...

  • Discuss how sampling plans must carefully determine sample locations and frequency to account for temporal and spatial variability in water quality data.

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 students are already familiar with stream discharge measurements.

How the Activity is Situated in the Course

This activity was taught after students had already measured stream discharge in several previous field exercises. This activity is intended to give students additional practice with that skill while introducing how discharge data is used for TMDL calculations. View the E-STEM field course timeline for more information about how this activity is situated in the course.

Description and Teaching Materials

Student Handout

Total Maximum Daily Load Handout (Microsoft Word 2007 (.docx) 18kB Apr24 20)


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