Problem Statement

Water bodies across the world are subject to inputs of non-point source and point source pollution. In the United States, many of our water bodies – streams, rivers, lakes – are listed as impaired for pollutants through the U.S. EPA Total Maximum Daily Load (TMDL) regulatory program. To develop solutions to these impairments, water resources engineers must answer important questions: how much pollution is in our water body and where is it coming from?

We can answer these questions by analyzing water quality data to determine pollutant loadings into our water bodies. A pollutant load is defined as the mass of a pollutant that is discharged into a water body over a period of time (e.g. kilograms per second). Pollutant loading estimation is helpful for identifying the relative magnitude of contributions from different sources in the watershed, evaluating the timing of pollutant source loading, and targeting future management efforts. In this module, students will use real flow and water quality data from USGS stream gauges to compute pollutant loads using both numeric integration and load duration curve methods. Students will also interpret their findings to determine where pollutant loadings may be coming from within the watershed.

Module Overview

In this module, you will use stream flow and water quality data from USGS gauges to compute pollutant loads and develop load duration curves.