Fisheries Research & Projects: February-March, 2009

Cleaning the air to help the water

Fisheries biologists at the Great Smoky Mountains are coordinating with state and federal agencies on a new initiative to reduce air pollution—and thereby reduce water pollution—in the Park. When stream samples show that water has a pH (acid level) below 6.0 for at least 10% of the time it’s sampled, that stream is listed as in violation of the Clean Water Act. The stream is also a poor habitat for many aquatic species, including acid-sensitive trout and salamanders. Many of the Smokies’ streams have pH levels below 6.0 10% of the time, and the Environmental Protection Agency (EPA) requires action: a reduction in water pollution. This means that a reduction in the source of the water pollution—emissions of sulfate and nitrate from the air— is also required.

How do biologists figure out how much we need to cut air pollution levels to reduce water pollution levels? A good question, and one that’s quite complicated. Several universities have developed computer modeling programs to predict the TMDL (Total Maximum Daily Load) of sulfate and nitrate pollutants that factories can emit without causing further acidification of the Park’s streams.

Currently, biologists are working with the Tennessee Department of Environment and Conservation (TDEC) and the EPA to select the model that will provide the best information on how to achieve the TMDL. Once it is chosen, states will have to commit to reducing air pollution levels. Over time, these reductions will reduce acid carried in the air to the park, and protect water quality and aquatic life. These changes are part of a larger movement to reduce sulfate and nitrate emissions—the main contributors to acid rain, snow, and clouds—from power plants throughout Tennessee and North Carolina, as the federal Clean Air Act, North Carolina’s Clean Smokestacks Act, and recent lawsuits mandate.


Last updated: April 14, 2015

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