APHN Discrete Water Quality Monitoring: Big South Fork NRRA 2024

Highlights

• There were no violations of water quality standards in WY24.

• E.coli was generally low at all sites, with two elevated results at Big South Fork at Leatherwood Ford.

• Conductance continued to be high at Pine Creek and New River, but results for all sites were at expected levels.

• Turbidity and nitrate levels were at or below recommendations.

• Overall, water quality conditions in WY24 were good throughout the park.

Background

Water resources within Big South Fork National River and Recreation Area (BISO) include approximately 80 miles (129 kilometers) of the Big South Fork of the Cumberland River along with its two major tributaries, Clear Fork and New River. In addition, there are hundreds of miles of tributaries and headwater streams within the park’s 125,000 acres. The BISO rivers and streams sustain nationally important freshwater fauna, including 11 federally-listed mussel species and the only population in existence of the federally-endangered tuxedo darter (Etheostoma lemniscatum). Big South Fork National River and Recreation Area supports one of the largest concentrations and some of the most pristine examples remaining of the globally imperiled Cumberlandian cobble bar or riverside scour prairie. These cobble bar prairies and the rare species that inhabit them thrive in the presence of frequent flood disturbance and are dependent upon natural flood regimes and unpolluted water. Big South Fork National River and Recreation Area occupies a small, downstream portion of its large (1,120 square mile) watershed, and therefore, the health of its aquatic systems is dependent to a large degree on external factors.

Issues of Management Concern

The primary threats to water quality at Big South Fork National River and Recreation Area are related to acid mine drainage from coal mines, sedimentation associated with roads and trails and historic mining, and impacts from timber harvest, agriculture, water development, and oil and gas activities in the watershed.

Monitoring and Objectives

The Appalachian Highlands Inventory and Monitoring Network (APHN) monitors water quality at strategic integrator sites to identify water resource conditions. Over 20 water quality parameters are measured at each sampling site. We use a YSI multisensor sonde to measure readings in the stream. In addition, we collect a water sample using a sampling technique, Equal-Width-Increment, to make sure our sample is depth- and steamflow- integrated and represents the entire stream channel. The sample is separated into aliquots. Some of the aliquots are used for tests in the APHN lab at Big South Fork NRRA and some are sent to the University of Tennessee Department of Civil and Environmental Engineering for further analysis.

Current conditions are compared to state and federal standards, as well as natural reference conditions within Big South Fork National River and Recreation Area. For detailed methods, see Hughes et al. 2018.

The network monitors a number of water quality parameters including:

Streamflow

The Big South Fork NRRA has free-flowing waters, where the rivers and streams are largely unimpaired by dams or diversions. Aquatic and riparian species rely on and have adapted to natural flows, including high flood pulses and low water periods.  Adequate flows, as well as scouring floods, are necessary for the survival of globally-imperiled cobble bar communities, as well as federally-listed fish, mussels, and plants at BISO. In addition, streamflow plays an important role in water chemistry, nutrient cycling, and geomorphic processes that shape river channels and floodplains. 

Water temperature

Most aquatic biological activity and chemical processes are affected by water temperature. This includes the kind of species that live in a stream, plant growth, mineral dissolution, and chemical reactions. Water temperature impacts many of the other water quality parameters we monitor.  Aquatic species, such as fish, insects, and the larval stages of many frogs, toads, and salamanders, have a preferred temperature range and are negatively impacted by warming waters.  Increasing water temperatures exacerbate issues like pollution, eutrophication, and disease.  Deforestation, dams, impervious surface runoff, and changing climatic conditions all contribute to warming stream temperatures. 

Tennessee state water quality standards specify that for fish and aquatic life, temperature shall not exceed 30.5°C (86.9°F). 

Dissolved oxygen

Dissolved oxygen is the amount of oxygen in a water body. As all aquatic organisms need dissolved oxygen to survive, it is an important indicator of freshwater health.  Main sources are transfer of oxygen from the air and from photosynthesis by underwater plants and algae. Algal blooms can increase dissolved oxygen at first, but when they die, decomposition by bacteria can deplete oxygen levels, leading to anoxic conditions that no longer sustain aquatic life. Natural changes in dissolved oxygen occur seasonally, as cold water can retain more oxygen than warmer waters, and daily, due to photosynthetic activity and water temperature. Typically, streams and rivers in Big South Fork NRRA have high dissolved oxygen levels and sustain an abundance of aquatic organisms. 

Dissolved oxygen must be above 5.0mg/l to attain Tennessee state water quality standards.
 

pH

pH is the concentration of hydrogen ions in water and is measured to determine how acidic or basic a water body is. The scale, from 0 to 14 standard units (SU), is logarithmic, meaning a pH of 6.0SU is ten times more acidic than a neutral pH of 7.0SU, and 5.0SU is one hundred times more acidic than 7.0SU. pH impacts the biochemical processes and metabolism of aquatic species, as well as the solubility and biological availability of nutrients and heavy metals. At a lower pH, metals are more soluble – meaning more easily dissolved in water and more toxic to aquatic life. Most aquatic species prefer streams and rivers near neutral (pH=7.0).   Most streams in Big South Fork NRRA are sandstone-influenced and have little buffering capacity to acidic inputs. Acid mine drainage from historic mining activities and exposed coal seams are the primary causes of low pH in park waters. Pollution from non-point sources and water treatment plants can contribute to increased pH.

Tennessee water quality standards specify that pH shall remain between 6.0 and 9.0 standard units.

Specific conductance

Rivers and streams naturally acquire dissolved solids as they run through rocks, soils, and general geology of their watersheds. Conductance is a measure of a waters ability to pass an electrical current, facilitated by the amount of dissolved solids in the water, including chloride, sulfate, nitrate, iron, and sodium ions. As it is a reflection of the underlying geologic composition of the watershed, conductance usually remains stable within a natural range – unless it is changed by outside impacts. High conductance can indicate pollution, such as runoff from agriculture, de-icers, impervious surfaces, or inputs from water treatments plants and other non-point source contributions. The Cumberland Plateau generally has low ionic waters, meaning conductance is low.

Reference conditions for conductance at Big South Fork NRRA is around 50 uS/cm for streams and 100 uS/cm for rivers. There is no state standard.

Escherichia coli (E. coli)

E. coli are bacteria commonly found in the intestines of warm-blooded organisms, including humans and animals. It is an indicator of fecal contamination in water, from sources such as runoff after rain, failing sewage systems, or agriculture and animal waste contributions. E.coli levels in streams and rivers are usually higher after heavy rain, as runoff moves through the landscape and disrupts sediment. 

APHN's water quality monitoring protocol does not test E.coli at a frequency necessary to meet Tennessee state water quality standards, which specifies two criteria requiring five samples collected within 30 days: a geometric mean of 126 colony forming units (cfu)/100ml and a <10% exceedance of 410cfu/100ml. 

The reference condition for E.coli in rivers at Big South Fork NRRA is <100cfu/100ml.

Turbidity

Excessive turbidity, a measure of how clear the water is, can not only hinder sunlight availability and visibility for aquatic life, but also carry bacteria, metals, and other chemical pollutants. In addition, turbid waters can lead to sedimentation of the streambed, negatively affecting freshwater mussels, aquatic macroinvertebrates, and fish. 

There is no numeric state water quality standard for turbidity in Tennessee.
The EPA ecoregion recommendation is <2.3 Formazin Nephelometric Units (FNU). 

Nutrients & Heavy Metals

Excess nutrients, such as nitrate/nitrite, in aquatic ecosystems can have detrimental impacts, including creating low-oxygen conditions through a process known as eutrophication. Additionally, ammonia, another form of nitrogen commonly used in fertilizers, can have significant negative impacts on sensitive organisms like endangered mussels.  

While certain metals serve a vital function for biological processes in streams, high concentrations of certain metals can be harmful for aquatic life. For example, aluminum can cause respiratory distress in fish as it builds up on their gills. 

Site #	Site Name
BISO_02	New River at New River, TN
BISO_03	Clear Fork at Peters Bridge
BISO_04	Clear Fork at Burnt Mill Bridge
BISO_05	White Oak Creek
BISO_06	Pine Creek
BISO_07	North White Oak Creek
BISO_09	Big South Fork at Leatherwood Ford
BISO_10	Laurel Fork of Station Camp Creek
BISO_08	Bandy Creek
BISO_11	Williams Creek
BISO_12	Bear Creek
BISO_13	Roaring Paunch Creek
BISO_14	Rock Creek
BISO_15	Big South Fork at Blue Heron
BISO_22	No Business Creek
BISO_17	Station Camp u/s Laurel Fork
BISO_16	Big South Fork at Yamacraw
BISO_18	Mill Creek near Stockton
BISO_19	Spruce Branch of NWO
BISO_20	Laurel Fork of NOW
BISO_21	North White Oak Creek at Zenith
BISO_23	Difficulty Creek
BISO_24	Troublesome Creek

Significant Findings

During water year 2024 (WY24), sampling occurred from October 2023 to September 2024. Including QA/QC, 79 samples were collected from 15 sites (see map above), following rotational panel 1 (Hughes et al. 2018). Beginning in WY23, sampling periods were reduced from quarterly to triennially.

There were no violations of Tennessee State Water Quality Standards in WY24. Water temperature and dissolved oxygen met all water quality criteria, with temperature remaining below 30.5°C (86.9°F) and dissolved oxygen above 5 mg/l. Water temperature ranged from 1.2°C to 30.0°C with a mean of 16.3°C for all site measurements. Dissolved oxygen ranged from a minimum of 5.2 mg/l to 14.1 mg/l. Mean dissolved oxygen across all sites was 9.6 mg/l.

There are no state standards for conductance. For waters of the Cumberland Plateau, natural reference conditions for rivers are below 100 µS/cm (microsiemens per centimeter) and below 50 µS/cm in smaller streams. Specific conductance was below 100 µS/cm at most sites, ranging from a low of 26.3 µS/cm at Laurel Fork of Station Camp Creek to a maximum of 333 µS/cm at Pine Creek at Toomey Bridge. New River at New River Bridge continued to have elevated conductance levels with a mean of 175 µS/cm. Mean specific conductance for all site measurements was 102.9 µS/cm.

Turbidity was low at most sites (mean = 5.7 FNU [Formazin Nephelometric Units]). Although the overall mean is above the recommended Ecoregion conditions of 2.3 FNU (EPA 2021), median turbidity was closer to this recommendation at 2.8 FNU. New River, Big South Fork at Leatherwood Ford, and Bear Creek were the most turbid sites.

NPS/Emma Brinley Buckley

As of March 2024, Tennessee state standards for Escherichia coli (E. coli) are based on a 30-day window and therefore, not achievable with APHN’s sampling design. E. coli reference conditions for the Cumberland Plateau are below 100 MPN/100ml. Mean E. coli for all site measurements was 91 MPN/100ml. There were two elevated E.coli results during WY24. Both occurred at Big South Fork at Leatherwood Ford after high waters when the hydrograph was receding.

Nitrate levels in Big South Fork waters were low, with 84% of samples below the minimum detection limits, meaning the amount was too low to quantify. Of the remaining 16% of samples above the detection level, results ranged from 0.06 mg/l to 1.04 mg/l with a mean of 0.31 mg/l. This average meets the EPA’s ecoregion recommendation of 0.31 mg/l. Bear Creek continues to have elevated levels of chloride (mean=23 mg/l) and sodium (18 mg/l), compared to the overall average for all sites at Big South Fork (mean chloride = 3.8 mg/l and mean sodium = 4 mg/l).

Water quality data are available upon request to the Appalachian Highlands Network. Past water quality reports and briefs are available on the Appalachian Highlands Network website.

This article was written by APHN Hydrologist, Emma Brinley Buckley
WY2024 data was collected by technicians Briley Bledsoe and Rhea Hester.
Contact: [e-mail]

Left: A wavy-rayed lampmussel (Lampsilis fasciola) displaying its lure on the river bottom. Center: A riverscour prairie next to the Big South Fork. Right: A threatened Cumberland Rosemary (Conradina verticillata) in bloom.

NPS/Emma Brinley Buckley