Taking the pulse of Smoky Mountain streams

Issue 4 > Partner Profile
Clouds at high elevation at the Appalachian Highlands Learning Center.

Clouds and fog bring acid pollution to the Smokies, particularly to high elevations.

NPS photo.

Why monitor the water?
Every living thing in the Smokies depends on water. Poor water quality—due to contaminants, invasive species, increased temperature, and more—not only affects the stream environment, but forests, soils, and animals outside the water as well. When water quality declines, we can lose animals and plants, and with them, critical links in the Park’s ecosystem.

To understand water quality, we have to look to the source of potential pollutants: the air. “Air and water quality monitoring are like taking the pulse of the park,” said University of Tennessee-Knoxville professor John Schwartz. “We have to have continuous monitoring,” he explained, to “answer critical management questions for natural resource protection.” One question deals with the impacts of acid contaminants (primarily sulfates and nitrates coming from air pollution) on streams and the larger ecosystem. We want to know how acidic the streams are, how fast they’re becoming acidic, and where in the park this stream acidification is the worst. In addition, Steve Moore, the Supervisory Fisheries Biologist at the Park with whom Dr. Schwartz conducts research, notes that we have lost native brook trout from six watersheds in which they used to be common. We don’t understand why the fish are disappearing in some watersheds but not others. The fish’s disappearance has driven much of the water quality research at the University of Tennessee.

Water samples ready for testing.

Water samples in the University of Tennessee lab ready for testing.

NPS photo.

Dr. Schwartz and his predecessor Dr. Bruce Robinson, along with many graduate students at the University of Tennessee, have been taking the pulse of the Smokies’ streams since 1991. They and volunteers from Trout Unlimited collect “grab samples” of water from 43 streams in different watersheds throughout the park. Every two weeks—winter and summer—they also take samples of rainwater, soil, and stream water from a long-term study site near Clingman’s Dome in the Noland Divide watershed. They chemically analyze the quality of the water, and use this basic data to ask more in-depth questions. Their analyses help us understand the patterns of pollution in the park and its impacts on the plants and animals we’re charged with protecting.

A hidden salamader enjoys neutral water.

Most salamanders, such as the one hiding on this streambank, can't tolerate acidic water.

NPS photo.

How healthy is the water?

Over many years, researchers at the University of Tennessee noticed that the water is becoming more acidic, especially at high elevations above 4000 feet. Even though our water looks clear and pristine, lab analysis reveals that it is contaminated with acidic sulfates and nitrates from air pollution.

Why does acidification matter? If you are a fish or insect larva, you prefer water that is neither acidic (like sour vinegar) nor basic (like smooth milk). You like neutral water with a pH around 7.0. Pure rainwater without any buffering minerals is slightly acidic—pH 5.6 or so—but minerals from rocks and soil capture this acidity and buffer it, so streams stay near-neutral. When rainwater is not just slightly acidic, but very—pH of 4.0 or even less—rocks and soil cannot buffer all of the acid. Much of it runs into streams, making them acidic as well. When stream water drops to pH 6.0—that’s 10 times more acidic than neutral 7.0 water—acid-sensitive fish and other creatures cannot survive. As the pH drops further, to 3.0-4.0 (as acidic as that sour vinegar), aquatic life cannot survive.

University of Tennessee-Knoxville doctoral students Keil Neff and Mei Cai are busy studying trends in water quality. Find out what questions they're asking and what they've found.

Fewer streams will have a healthy pH above 6.0 in the future.

If acid pollution continues, the percent of Smokies streams that are good habitat (pH of 6.0 or above) will drop in the next 50 years.

NPS graphic.

What’s the future for aquatic plants and animals?
We’ve already seen brook trout disappear from streams where they were common just 15 years ago as the pH drops below 6.0 and flushes more toxic aluminum into the water. With continued drops in pH, scientists think that brook trout may be gone from the Park entirely in 25-50 years. By 2070 all of the Park’s streams could have a pH less than 4.0, a level that is unlivable for most aquatic animals here today.

But it's not all doom and gloom. There is hope to alter these trends by reducing air pollution so the predictions never come true. Through a combination of individual, community, and legal actions, we can change the way we live and, by doing so, improve water quality. The most recent check-up, from the 2008 Annual Water Quality Report, says that we can even be cautiously optimistic about at least some of the results:

  • pH range across 43 sample sites in Park = 4.8-7.4
  • Average pH = 6.3 (up from 17-yr average)
  • Average pH of rain = 5.64 (up from 17-yr average)
  • Average pH of throughfall (rain through trees) = 4.7 (up from 4.2, the 17-yr average)
  • Trends in sulfate & nitrate deposition = less acid is falling, due to long-term drought (less acid precipitation) and/or emissions reductions from power plant scrubbers
Hybrid energy cars help reduce emissions.

Hybrid cars help reduce emissions.

NPS photo.

Reversing trends through research and action

Everyone can help the Smokies’ streams by reducing acid pollution at its sources. As Dr. Schwartz said, “We need to address the problem from a public standpoint, because sulfates and nitrates are coming from air pollution. Ideally we’d put pressure on congressional representatives to clean up coal-fired power plants. The new scrubber installed at some of the East Tennessee coal-fired power plants will help, but we need more. We also need to reduce vehicle emissions as well because it is a major source of the airborne nitrates.” Vehicle emissions include exhaust from passenger cars, buses, and off-road vehicles such as boats, lawnmowers, and construction equipment.

While we’re advocating enforcement of existing laws and promoting new rules to regulate air pollutants, we can reduce our personal contributions to acid pollution.

  • Nitrate cuts: drive less, take mass transit, carpool, tune up cars, drive fuel efficient vehicles
  • Sulfate (and electric bill) cuts: weatherproof homes, keep thermostats at 78 degrees in summer and 68 in winter, change to compact florescent bulbs, and use the clothes drier less

Small things make a difference; even when you’re at home, shutting the fridge door or flipping off that light when you leave the room can help a fish high in a Smoky Mountain stream.

Researchers are constantly asking new questions and seeking their answers—you could join them by studying water quality in college and graduate school. Dr. Schwartz and his students want to find out the answers to these big questions:

How does soil hold and release sulfates over time?
Soil is a fascinating mix of organic (plant and animal) and inorganic (rock and mineral) material. It holds chemicals—both natural and introduced—and metals, and releases them to plants and into the water. If we reduce the amount of acid pollution coming into the park, how long will acid stored in the soil leach into the water? How does soil hold and release ions—including magnesium, calcium, and sodium? How are plants such as dogwood reacting to lower amounts of calcium, which they use to grow, in soil?

How do regional reductions in air pollution help water quality in the Smokies?
We could guess that cutting emissions from power plants and vehicles would also reduce the amount of acid falling on the Smoky Mountains. But we as a society depend on electric energy and fossil fuels. So how much do we need—legally and ecologically—to cut air pollution to make our streams healthy?

This is where TMDL, or Total Maximum Daily Load, comes in. It is the total amount of acid pollution that park could receive from the air and still have streams that meet the Clean Water Act’s requirement: a pH above 6.0. You can read more about TMDL (Total Maximum Daily Load) work in the Meet the Managers feature.

Professor John Schwartz.

Professor John Schwartz in the Smokies.

NPS photo.

Scientist profile
Dr. John Schwartz has taught at the University of Tennessee since August, 2003. He earned his Master of Science degree in Fisheries at Oregon State in Corvallis, OR, and his PhD at the University of Illinois studying Environmental Engineering. In between these degrees, he gained on-the-ground experience working for the Environmental Protection Agency in water quality enforcement, and for an Oregon consulting firm planning and designing municipal water, wastewater and stormwater systems. Dr. Schwartz was pulled into the fold of water quality modeling at the Smokies shortly after he came to the University of Tennessee. He started working with Dr. Bruce Robinson, who then coordinated all of the water quality research with Fisheries Biologist Steve Moore at the Smokies; when Dr. Robinson retired, Dr. Schwartz inherited the project. “I’ve always had an interest in water quality, and especially the biological side,” said Dr. Schwartz. He also enjoys teaching, and says it’s important to bring “real world” problems into the classroom, as he does in his undergrad hydraulics class. Dr. Schwartz serves as an advisor to many water quality graduate students who research acid deposition, soil chemistry, and other key issues related to water quality in the park. “At the graduate level,” he said, “I can work very closely with students. After they get out and get a job, you can see them advance in their careers. This is a nice feeling!”

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