Living Waters: A Study of the Effects of Elevation on Water Quality and Biota in Great Smoky Mountains National Park

Part of the Young Naturalist Awards Curriculum Collection.

by Sterling, Grade: 8, Tennessee - 2012 YNA Winner


Chestnut Branch in Great Smoky Mountains National Park is located at an elevation of 1,200 feet.

Cold, clear water races over mossy rocks. Delicate beams of sunlight filter through the tall trees to illuminate the shapes of hundreds of tiny insects buzzing just over the water’s surface. A loud splash resonates over the creek bed as a brook trout leaps from the water to capture a juicy stonefly. This idyllic scene typifies the lush natural beauty of streams in Great Smoky Mountains National Park in Tennessee. Proclaimed as one of the most species-rich, biologically diverse areas in the world, this 600,000-acre wonderland features over 700 miles of wild streams churning through its lush interior. Like a network of arteries, veins and capillaries, these waterways supply the area with the life-giving fluid, water, which is essential to all creatures in the park (Rutter 2003).

Because water is essential to the survival of all living things, protecting this valuable resource is vitally important. Water quality is a measure of the condition of water relative to the requirements of one or more biotic species (Hennessy 1998). Knowing water’s physical, chemical and biological characteristics allows experts to determine whether it is suitable for aquatic life or human consumption. In the United States, agricultural runoff and urban and wastewater discharges contribute to the contamination of water resources. Water-quality standards in the United States are created by state agencies for different types of water bodies and their locations, based on their desired uses. The Clean Water Act requires each governing jurisdiction to submit a set of biennial reports on the quality of the water in their area. These reports are submitted and approved by the Environmental Protection Agency (Florida State Department of Education 2009). Water quality is generally determined by the completion of a series of biological assessments as well as a variety of chemical tests such as pH, temperature, nitrate and phosphate levels, and dissolved oxygen (Gada 2010).

Finger in yellow glove pointing at larvae.
Water pennies are actually diving beetle larvae. Because they are such sensitive organisms, they are indicators of good water quality. These specimens were found in Forge Creek.

The pH of water is important to aquatic life. If the pH falls below 4 or above 9, all life forms die. The pH is a measurement of the acid/base activity in a solution. The pH scale runs from 0 to 14; a pH measurement of 7 is neutral. A pH less than 7 is acidic and greater than 7 represents alkalinity. A pH range of 6 to 8.5 is common for natural waters. Lower pH values can be caused by the deposition of acid formed by substances in precipitation, called acid rain. The pH levels can also be affected by wastewater discharge, runoff from mining operations, and the types of rock naturally found in the area (Gada 2010).

Temperature is another very important part of a stream’s ecology. The water’s temperature affects the dissolved oxygen capacity of the water. The ratio of the dissolved oxygen content to the potential capacity of the water gives the percent of saturation, which is an indicator of water quality. Since temperature fluctuates during each day and according to the seasons of the year, dissolved oxygen levels also fluctuate accordingly (Gada 2010).

The rapids at Big Creek make a loud roar as the water pounds over boulders. This stream's dissolved oxygen level was 11.84 ppm.

Depletions in dissolved oxygen levels can cause major shifts in the kinds of aquatic organisms found in water. Much of the dissolved oxygen in water comes from the atmosphere. After oxygen is dissolved at the surface of the water, it is distributed by turbulence and currents. Algae and rooted plants also deliver oxygen to the water through photosynthesis (Murphy 2009). Buildup of organic wastes is the major factor contributing to changes in dissolved oxygen levels. Decay of organic wastes consumes oxygen and is often concentrated in summer, when animals require much more oxygen to support higher metabolisms. Oxygen tends to be less soluble as the temperature of the water increases. Warmer water will contain less oxygen than cold water. So, levels of dissolved oxygen are higher in winter and lower in summer. Water at 21°C will be 100% saturated with 8 parts per million dissolved oxygen. However, water at 8°C can hold up to 12 parts per million before it is 100% saturated ( A concentration of dissolved oxygen less than 4 parts per million is stressful for most forms of aquatic life (Murphy 2009).

Velocity of the water flow also influences levels of dissolved oxygen. During dry seasons, water levels decline and the flow rate of the water slows down, so dissolved oxygen levels drop. When dissolved oxygen levels drop, species that need a high concentration of dissolved oxygen, such as mayfly nymphs, stonefly nymphs, caddisfly larvae and trout, will move out or die. They will be replaced by organisms such as sludge worms, blackfly larvae and leeches, which can tolerate lower dissolved oxygen levels (University of Colorado at Boulder 2009).

During my study I found some enormous insect larvae! This Mayfly larva was found at Metcalf Bottoms which registered a dissolved oxygen level of 12.12 ppm.

Biological assessments, or bio-assessments, are an evaluation of a water body using biological surveys and other direct measurements of the resident living organisms. Biological assessment data are important for measuring the attainment of water-quality standards for the protection of life. Such data can provide a clear picture of whether a body of water is meeting the needs of its designated aquatic creatures. Biological assessments reflect the total cumulative impact of all stressors over a period of time on a biological community. As such, they are a unique measurement, providing information that no other measurement can. Bio-assessment data can also be used to establish or refine the aquatic life as a resource management tool. Biological data can address taxa and family order richness, threatened and endangered species, relative abundance, alien or invasive species, and reproductive success. All of these factors are great indicators of water quality. (EPA 2009).

The waters of Rough Fork were so clear that I could see this crawdad on the bottom of the stream.

However, water quality can be difficult to measure, especially in areas such as the Great Smoky Mountains National Park (“Return of the Native” 2007). A vast network of branching rivers, streams, creeks and springs exists in the park. The crystal-clear water in many streams can be deceiving because not much can be determined by simply looking at the water. Most pollutants are invisible to the naked eye. Three major types of pollutants affect water quality: sediment, bacteria and nutrients. When rain washes sediments into streams, tiny organisms and fish eggs clinging to the rocks on the river or stream bed can be smothered. Dirt can also clog gills and suffocate fish. Too much dirt in a water body can block the sunlight that plants use to conduct photosynthesis. If the plants do not get enough sunlight to grow, not only do the plants die, but they also do not make oxygen through photosynthesis that organisms such as fish need to survive. Bacteria in water are not all harmful. Some, however, are pathogenic, meaning they can cause disease in humans. The primary pollutants in water pollution are nutrients such as nitrogen and phosphates, but there are many others. This type of pollution exists in more than 3.8 million acres of lakes, ponds and reservoirs nationwide. Excess nutrients can cause algae to grow out of control and use all the available oxygen in water, killing off other organisms that need oxygen to live. This excessive growth can also block sunlight and cause the death of plants and other aquatic organisms (Florida State Department of Education 2009).

Anakeesta rocks are easily spotted in Walker Prong alongside Highway 441. The rusty red color of the rocks indicates that they have a high iron content.

Water quality is also closely associated with the surrounding environment and land use. Geology of the watershed is a prime influence on water quality. For example, Beech Flats Prong in Great Smoky Mountains National Park suffers from a lowered pH because of Anakeesta rock formations that were exposed years ago during the construction of Highway 441 through the national park (Rutter 2003). Another area of the park, Cades Cove, has the highest concentrations of sulfate and calcium due to the area’s carbonate geology. These factors strongly influence water chemistry (Ames 2008).

The weather can also have a major impact on water quality. Generally, the water quality of streams and rivers is best in the headwaters, where rainfall is often abundant. Water quality frequently declines as rivers flow through regions where land and water use are intense, and pollution from agriculture, large towns, and industrial and recreation areas increases. However, there are exceptions to this rule, and many such circumstances exist in Great Smoky Mountains National Park, where high-altitude streams are literally dying due to acid deposition. In the national park, heavy rains in some high-altitude streams, as well as the soil composition of the stream beds, often create unusually acidic conditions resulting in a very low pH (Moore 2009).

Since the 1980’s, national air-quality monitoring has shown that the Great Smoky Mountains National Park receives some of the highest rates of atmospheric deposition of acid pollutants in the United States (Shubza et al.,1995; NADP 2006; Sullivan et al.,2007), which has been linked to emissions from regional coal-fired plants (Chestnut & Mills 2005). Most of the streams in the national park reflect lowered pH chronically and episodically (Robinson et al.,2005, 2008; Dayton et al.,2008). The soil and rocks in stream watersheds cannot neutralize the pollutants. A major concern of streams with low pH is the release of chemicals, such as aluminum, which can be highly toxic to fish (Baldigo & Murdoch 1997; Neff 2007).

The right prong of the Greenbrier River registered a pH of 6. The leaves that had fallen in the water may have contributed to the low pH

Acidic episodes often occur in high mountain streams in Great Smoky Mountains National Park after heavy rains. The rains carry pollutants such as sulfur dioxide and nitrous oxide from the air down to the soil and water. This mixture creates a mild solution of sulfuric and nitric acid. Native brook trout, a species especially sensitive to acidic water conditions, have been virtually eliminated in six headwater streams in the park, including some streams that were populated as recently as 15 years ago (Moore, pers. comm., 2006; Neff et al., 2009). Sunlight increases the rate of these reactions. Dry deposited gases and particles are sometimes washed from trees and other surfaces by rainstorms. This runoff combines with acid rain, making the combination more acidic than the rain alone. This combination of acid rain plus dry deposited acid is called acid deposition. Prevailing winds transport the compounds sometimes hundreds of miles across state and national borders ( Because of the continued decline in pH, resource managers at Great Smoky Mountains National Park are concerned that brook trout will be eliminated from the park within 25 to 50 years (Robinson et al., 2008). Because of concerns about the potential impact of atmospheric deposition of acid pollutants on water quality, water-quality studies began in Great Smoky Mountains National Park in the 1970’s. A long-term water-quality program began in 1991 to assist in understanding these impacts and to improve resource management strategies (“Great Smoky Mountains National Park Water Quality Report” 2008).

A stream, Beech Flats Prong, flowing past large mossy rocks with fallen leaves on them. This stream registered a pH of 6 and is on the list of impaired streams in the national park.
Beech Flats Prong registered a pH of 6. This stream is named on the list of impaired streams in the national park.

Park-wide stream surveys began in October 1993 to identify the potential impact of acid deposition on streams in the Great Smoky Mountains National Park and to monitor long-term changes in stream acidification. Data from the 1990’s found that 97% of the 90 sampling sites were classified as sensitive, extremely sensitive or acidic. In addition, 77% of the sites were found with median pH values that could have adverse effects on aquatic organisms. Park-wide stream monitoring has provided an extensive database that continues to answer important questions about the impact of acid deposition on streams in Great Smoky Mountains National Park. If conditions remain the same and past trends continue, forecasting models suggest that 30% of the sampling sites will reach pH values of less than 6 in less than 10 years, 63.3% in less than 25 years, and 96.7% in less than 50 years (“Great Smoky Mountains National Park Annual Water Quality Report” 2008). In 2006, 12 streams in the national park were listed as impaired due to low pH from atmospheric deposition and unknown sources. These streams were found with pH samples below 6 (“Great Smoky Mountains Annual Water Quality Report” 2008).

Eighth grade award winner named Sterling. The boy is standing knee-deep in a river holding piece of equipment.
I wanted to find out how elevation affects water quality in Great Smoky Mountains National Park, so I decided to conduct and investigation on my own.

Despite air quality improvements in the park over the past few decades, stream acidity is still increasing because of chemical changes in the soil, said Steve Moore, chief fisheries biologist for Great Smoky Mountains National Park. “It’s happening all up and down the East Coast,” Moore said. “I don’t know of a more critical issue in park resource protection. Acid deposition is basically an ecosystem-wide effect. I wish we could turn a spigot and shut it off, but there is no quick fix” (Knox, 2010).

My Study

As an aspiring fly fisherman, I have a deep love and concern for protecting the streams in Great Smoky Mountains National Park. I thoroughly enjoy spending time in the park’s streams, trying to snag a sizable trout or simply watching all the water creatures and absorbing the park’s peace and natural beauty. Water is a vital resource for the park, as it is to all living creatures. My concern for the park’s waters increased on April 8, 2011, when a tragic accident at the Gatlinburg, Tennessee sewage facility resulted in millions of gallons of raw sewage being spilled into the Little Pigeon River, which flows out of Great Smoky Mountains National Park. The accident led me to think about the impact that nearby tourist towns must have on the streams that flow through them, and I grew to appreciate the high waters of the mountains. Logically, the streams in the high-altitude areas of the Smoky Mountains would be much healthier than those at lower altitudes. As I began reading about water quality in the park, however, I learned about the destructive effects of atmospheric deposition on high-level streams. So I decided to launch my own investigation.

Materials and Methods

A split image. On the left is a map showing the streams in the study. On the right is data sheet with observations made in the field.
L: A map showing the streams included in the study. R: I designed a data sheet to collect information for the study.

Since I wanted to collect data in the national park, I had to apply for a research permit through Paul Super in the resource management department. When that process was completed, I selected 25 streams for the study [See Appendix A]. Ten of the sites selected for the study were at elevations above 2,000 feet. Fifteen of the sites were at elevations below 2,000 feet. I purchased four La Matte Water Quality Test Kits to use in conducting the chemical tests on the water samples. The research permit specified that I would be required to follow special protocols in collecting my data. Specifically, none of the chemical tests could be done in the national park. I would be allowed to collect no more than 40 ml of water for the tests. No organisms could be collected from the park; they could only be counted. The final specification was that I had to treat the boots or waders that I wore in the streams with a light bleach solution after leaving each stream. This would keep me from carrying bacteria or aquatic contaminants from one stream to another. I felt all these restrictions were very reasonable, and I was honored that I was trusted to follow proper procedures while collecting data in the park. I also prepared a water-quality assessment datasheet to use in recording information about weather conditions, a description of the stream, and the water temperature, pH level, dissolved oxygen level and elevation of the stream. I created a page to record information for an aquatic life inventory. I planned to spend 30 minutes in each stream to check for organisms in the water or under rocks. I enlisted the help of family members to tally the numbers of specimens that I found. The organisms were identified using a key provided by the Save Our Streams organization. I purchased a pair of boots first, and later borrowed some chest waders for the project when temperatures got very cold. Obtaining the research permit took longer than I expected, so I was not able to start collecting data until September 28, 2011. Since I could only find time to collect data on weekends, the chilly fall temperatures arrived and the water was very cold! At Walker Prong, for instance, the water temperature was 3°C! To assist in keeping records of the project, numerous photographs were taken of each site and of the specimens found in the water.

Data Analysis and Results


The first data I analyzed compared pH levels with the streams’ elevations. Even though 25 streams were included in the study, I was able to group the elevations into 12 measurements to make a chart. I averaged the pH levels for each elevation and put that information on a chart. The data revealed that the high-elevation streams in my study reflected lower pH levels. The mean pH level for streams above 2,000 feet was 6.6. For streams below 2,000 feet, the level jumped to 7.8. The data suggests that as elevation increases, stream pH declines. Even though my study found no pH levels below 6, research by scientists indicates that substantially lower levels have been found, especially after heavy rain. At pH levels below 6, biota in the stream usually begin to show effects, according to research on this topic (Cherry et al., 1984). The Environmental Protection Agency uses pH levels as a parameter to determine “impairment” of streams. Currently, 12 streams in Great Smoky Mountains National Park are listed as impaired because of low stream pH (“Rules of Tennessee Department of Environment and Conservation” 2008).


The second set of data related to the levels of dissolved oxygen. The test kit had tablets that were designed to measure dissolved oxygen levels, but I learned that a chart that references the level of dissolved oxygen based on water temperature is much more accurate. When I made a chart relating the dissolved oxygen data to elevation, I was not surprised to see that the higher levels of dissolved oxygen were found at higher elevations. This was largely because of lower temperatures at the higher elevations, which enable the waters there to contain more oxygen.

Probably the most valuable (and most enjoyable) portion of my study was the biological inventory. I spent 30 minutes at each of the sites taking an inventory of all the life forms found in the river. I checked under rocks and along the shore for living creatures. I identified all the specimens using field guides, and I had a family member tally my discoveries on the data sheet.


The organisms were grouped in three categories based on their level of sensitivity to water conditions. I added all the totals and multiplied by three to arrive at a “Stream Index Value” for each stream. I based the procedure for the biological inventory on information I obtained from Save Our Streams. I averaged the Stream Index Values for the 12 levels of elevation, and charted the data. I found the highest Stream Index Values at streams near an elevation of 1,800 feet. A fairly steady decline in the number of organisms found was evident as the elevation increased, with one of the lowest Stream Index Values found at Walker Prong, the highest elevation site in the study.

The average Stream Index Value for streams at elevations above 2,000 feet was 145. The average Stream Index Value for streams at elevations below 2,000 feet was 262. I felt this data did point out a relationship between elevation and species richness, but the cause of this relationship was not obvious. Research indicates that abiotic factors change with elevation. Furthermore, since species richness was higher in lower-elevation streams, the data corresponded with the “river continuum concept,” a model for classifying and describing flowing water by classifying sections of waters based on the occurrence of indicator organisms.


As I completed my personal investigation of the effects of elevation on water quality and biota in Great Smoky Mountains National Park, I learned that determining water quality in the park is a complex, long-term process. Although my data pales in contrast to the volumes of data already collected by the resource managers who monitor water quality, completing this study was an extremely rewarding, enjoyable educational experience for me. Through this study, I gained a deeper appreciation for the intricate relationships that exist in aquatic environments, and I now have a strong desire to be an advocate for new environmental policies that tighten restrictions on coal-burning businesses. The more I learn about the world, the more aware I become that no organism exists independently of others. The world is an intricate web of life, and as higher forms of life, humans are stewards charged with protecting more fragile beings. If cooperative efforts between state regulatory agencies, the Environmental Protection Agency, and utility interests to reduce nitrogen oxides and sulfur dioxide pollutants in the air succeed, the day may arrive when all high-elevation streams once again contain truly living waters.

Appendix A

Streams Included in the Study: 

Name of Stream Elevation Dissolved Oxygen pH Level Stream Index Value
1. Abrams Creek 1,207 feet 9.65 ppm 8 141
2. Greenbrier River (Main) 1,207 feet 11.83 ppm 8 171
3. Fighting Creek  1,207 feet 9.65 ppm 7 135
4. Greenbrier River (Right) 1,507 feet 11.55 ppm 6 222
5. Big Creek 1,700 feet 11.84 ppm  8.5 390
6. Chestnut Branch 1,700 feet 11.84 ppm  8.5 318
7. Tater Branch 1,715 feet 11.29 ppm 8.75 165
8. Anthony's Creek (Left) 1,800 feet 11.03 ppm 8 285
9. Anthony's Creek (Right) 1,800 feet 11.56 ppm 8.5 300
10. Deep Creek 1,800 feet 12.43 ppm 6 438
11. Metcalf Bottoms 1,827 feet 12.12 ppm 8 324
12. Forge Creek 1,900 feet 11.56 ppm 9 201
13. Abrams Creek(Sparks Ln.)  1,917 feet    11.29 ppm 8.5 439
14. Cooper Branch 1,917 feet    11.29 ppm 6 130
15. Sea Branch 1,917 feet    11.29 ppm 8.5 375
16. Oconoluftee River 2,040 feet 12.43 ppm 8.5 148
17. Mingus Creek 2,132 feet 10.76 ppm 6 129
18. Greenbrier River (Left) 2,165 feet 12.43 ppm 6.5 148
19. Cataloochee Creek  2,680 feet 10.29 ppm 7 141
20. Shanty Branch         2,680 feet 11.27 ppm 7 68
21. Rough Fork 2,680 feet 11.27 ppm 7 165
22. Beech Flats Prong 2,802 feet 11.27 ppm 6 192
23. Alum Cave Creek 3,852 feet 11.27 ppm 7 141
24. Mt. Sterling Creek 3,888 feet 12.45 ppm 7 222
25. Walker Prong 3,957 feet 13.44 ppm 6 138


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