United States

Department of

Agriculture

Forest Service

Northeastern

Research Station

Research Paper NE-708

Alexander C. Wooten

James Preer

Pamela J. Edwards

Geologic and Tributary

Influences on the Chemistry

of a Headwater Stream
Published by: For additional copies:

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Abstract

Water samples were collected weekly from June 12 to August 14, 1995, from Big

Spring Run (BSR) in West Virginia. BSR originates in Big Spring Cave, where three

stream samples were collected. In addition, 18 BSR sites were sampled

downstream from the cave, three from its tributaries, and one above and below the

stream’s confluence with Elklick Run. Along its length (653 m), the geology is

Greenbrier limestone in the headwaters, Pocono sandstone in the midsection and

Hampshire sandstone and shale in the downstream section. As a result, water

chemistry was strongly influenced by biogeochemical and hydrologic processes.

The Authors

ALEXANDER C. WOOTEN is a graduate student with the Department of

Environmental Science at American University, Washington, DC.

JAMES PREER is professor of environmental science at the University of District of

Colombia, Washington.

PAMELA J. EDWARDS is a research hydrologist with the Northeastern Research

Station’s Timber & Watershed Laboratory at Parsons, West Virginia.

Manuscript received for publication 30 December 1998

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1

Introduction

The chemistry of forest streams is the result of many

biogeochemical processes. As a result, streamwater

chemistry can be highly variable, which, in turn, can

greatly affect the populations, diversity, and habitat of

aquatic organisms, in-stream nutrient cycling, and

potential uses of the water resource.

Water quality at a particular location along a stream

length can be influenced so greatly by one or more

variables, that there is little change in chemistry for

long distances—even if these variables are absent

downstream. In this situation, the dominant influence

may be diminished only by dilution, e.g., nonaffected

soil water, groundwater, or tributaries entering the

stream channel. In other systems, particularly those

with low ionic strength, even small physical, chemical,

or biological changes can affect water quality.

The objective of this study was to examine the

influences of geology and tributary inputs on the

chemistry of a headwater stream in the central

Appalachians. Along its length, the bedrock geology

changes three times and the mineralogy is much

different in the headwaters than near the mouth.

Because the stream originates within a cave, the

physical environments differ between the uppermost

and downstream reaches. Thus, this 653-m stream is

ideal for examining the effects of biogeochemical

extremes on water chemistry over a relatively short

distance.

Methods

Study Site

The study stream, Big Spring Run (BSR), is located

within the USDA Forest Service’s Fernow

Experimental Forest in Tucker County, West Virginia

(latitude: 39°2¢302N; longitude: 79°40¢002 W). BSR

originates within Big Spring Cave and continues for 653 m to

its confluence with Elklick Run (Fig. 1). Surficial streamwater

is present within the limestone cave, but the stream runs

below ground and resurfaces outside the cave at the base of

a limestone outcrop.

The cave and point of resurgence are located within the

Mississippian-age Greenbrier limestone formation (Fig.1).

Eighty-seven percent (by weight) of Greenbrier limestone is

composed of calcium carbonate (CaCO3

) (Reger 1923).

Almost immediately downstream of BSR’s resurgence to the

surface, bedrock geology is Pocono sandstone (also

Mississippian age) (Fig. 1). Finally, for approximately onethird of the stream’s length, the geology is the Hampshire

Series (Devonian age). This bedrock is a fine-ground

micaceous sandstone and shale that is about 68 percent

quartz (Reger 1923).

Three small unnamed tributaries (T1-T3) also feed into BSR

(Fig. 1). Surface headwaters of tributary T1 originate in the

Figure 1.—Approximate locations of sampling sites in the 653-

m Big Spring Run (1-18), tributaries (T1-T3), and Elklick Run

(E1-E2). Contour line designations are in feet.

Greenbrier formation and enter BSR in the Pocono

formation. Surface waters of tributary T2 are entirely within

the Pocono formation. Tributary T3 begins in the Pocono

formation but is mostly within the Hampshire formation.

Sampling Sites and Procedures

From June 12 to August 14, 1995, one-liter grab samples

were collected every Tuesday at 3 sites in Big Spring Cave

(C1-C3), 18 sites in BSR downstream of the cave (1-18), 1

site in each tributary just upstream of their confluences (T1-

T3), and in Elklick Run just upstream (E1) and downstream

(E2) from the BSR confluence (Fig.1). Samples were

collected from the thalweg and at middepth when possible.

High-density polyethylene bottles were rinsed three times

with streamwater prior to sample collection. The bottles were

cleaned (Edwards and Wood 1993) but were not acid

washed because samples were not analyzed for metals.

Water samples were returned to the Northeastern Research

Station’s Timber and Watershed Laboratory at Parsons,
2

West Virginia (about 16 km from BSR) for analyses of

electrical conductivity, pH, alkalinity (as CaCO3

), calcium

(Ca), sulfate (SO4

), and nitrate (NO3). Protocols approved by

the U.S. Environmental Protection Agency were used

(Edwards and Wood 1993). Water temperature and

dissolved oxygen (O2

) were measured in situ at each

sampling point with a YSI model 57 meter1

.

Results and Discussion

Electrical conductivity was high along the entire length of

BSR, averaging 144.8 mS cm-1 (Fig. 2). This result reflects

limestone in the headwaters. In many nearby streams that

flow through only sandstone and/or shale, average

conductivity is less than 30 mS cm-1 (Kochenderfer and

Edwards 1991; Helvey et al. 1982; Stephenson et al. 1995).

The influence of limestone was not diluted as the stream

flowed through less soluble materials and received tributary

waters from these areas, i.e., average conductivity was

about 150 mS cm-1.

Alkalinity and Ca were the primary contributors to

conductivity. This is not surprising because of the limestone

in the headwaters. Equivalent conductivity calculations (see

Edwards and Helvey 1991) showed that these two

components accounted for 87.6 percent of the average

conductivity along the length of BSR.

Calcium and alkalinity did not change significantly along the

length of BSR (Figs. 3-4), that is, the regression slopes of

concentration vs. distance were not significantly different

from zero. Both Ca and alkalinity increased slightly

downstream (for about 100 m) of the confluence with T2,

which had significantly higher concentrations of both

constituents than BSR. Tributary T1 had no effect on Ca or

alkalinity in BSR. Presumably, the flow contributions from T1

were insufficient to alter the chemistry of BSR, even though

T1 had higher concentrations than T2. Although streamflow

was not measured in this study, T2 appeared to contribute

more flow to BSR than T1.

If geology alone was responsible for the elevated Ca and

alkalinity in T1 and T2, these concentrations would have

been similar to those in BSR. We believe that dust-size

particles of limestone on the limestone-graveled road uphill

from and adjacent to T1 and T2 (Fig. 1) caused the elevated

Ca and alkalinity (the road is only about 3.5 m from the

streambanks in some locations) (Helvey and Kochenderfer

1987).

The buffering capacity of streamwater from the Greenbrier

formation dominated the entire length of BSR. Both Ca and

alkalinity were close to their headwater values over the 653-

m stream length (Figs. 3-4). Even the contribution of waters

from T3, which had negligible concentrations of alkalinity

and Ca, did not significantly dilute or reduce headwater

characteristics. The dominant chemical influence of the

headwaters of Big Spring Run was apparent even after

merging with the less alkaline Elklick Run; Ca and alkalinity

were higher in E2 (downstream from the confluence) than in

E1 (Figs. 3-4).

The high Ca concentrations were associated with

streamwater pH from 7.17 to 7.53; pH was slightly lower

within Big Spring Cave and for the first two sampling sites

near the cave, averaging 7.21 (Fig. 5). Downstream, pH

increased steadily, reaching 7.5 and remaining at

approximately that value nearly to the stream’s confluence

with Elklick Run.

The pH values downstream may have been higher due to

tributary inputs, and/or they may have been an artifact of

pH depression within the cave and the initial resurgent

samples. The elevated pH in T1 and T2 (Fig. 5) may have

caused the pH of BSR to increase to pH 7.5 downstream

from their confluence. Because an approximate increase of

only 0.5 unit would have been needed, the tributaries might

have influenced this change while not substantially

influencing alkalinity and Ca for a long distance

downstream. The pH within the cave could have been

depressed if the partial pressure of carbon dioxide (CO2

) in

cave water had been higher than in the resurgent stream

(Hem 1970). In the confined cave atmosphere, CO2

diffusion to the ambient atmosphere would be retarded.

After exiting the cave, excess CO2 would be liberated to the

ambient atmosphere and pH would increase until an

equilibrium was attained.

As with Ca and alkalinity, BSR influenced the pH of Elklick

Run. The average value of the samples from Elklick Run

upstream from the BSR confluence was 7.27; downstream

from the confluence, the average pH was approximately

7.35.

Concentrations of SO4

 and NO3 also were lower in the cave

than immediately downstream from it (Figs. 6-7). These

apparent decreases may have been due to lower oxidation

rates within the cave relative to those present in water

exposed to the ambient atmosphere. However, if oxidation

was retarded, the controlling factor was not a lack of

dissolved O2 because the latter was highest within the cave

water (Fig. 8).

Sulfur and nitrogen oxidation result from microbial reactions

(Brady 1984), though auto-oxidation of sulfide can occur in

alkaline waters (Stumm and Morgan 1981). Besides O2,

temperature and organic carbon are the primary

physicochemical factors controlling these processes (Brady

1984; Janzen and Bettany 1987). Temperatures within the

cave were relatively constant throughout the year and were

neither extreme nor microbially inhibiting (Brady 1984; Fig.

8). It is more likely that differences in organic carbon

availability were responsible for the differences in SO4

 and

NO3

 concentrations inside and immediately outside the cave.

1

The use of trade, firm, or corporation names in this paper is

for the information and convenience of the reader. Such use

does not constitute an official endorsement or approval by

the U.S. Department of Agriculture or the Forest Service of

any product or service to the exclusion of others that may be

suitable.
3

Figure 2.—Average electrical conductivity at each sampling site. Negative distances on the x-axis

indicate sampling sites within Big Spring Cave.

Figure 3.—Average calcium concentrations at each sampling site. Negative distances on the x-axis

indicate sampling sites within Big Spring Cave.

Distance from cave outlet (m)

Conductivity (uS cm-1)

Distance from cave outlet (m)

Calcium (mg L-1)
4

Figure 5.—Average pH at each sampling site. Negative distances on the x-axis indicate sampling sites

within Big Spring Cave.

Figure 4.—Average alkalinity concentrations at each sampling site. Negative distances on the x-axis

indicate sampling sites within Big Spring Cave.

Distance from cave outlet (m)

Alkalinity (mg CaCO3 L-1) pH

Distance from cave outlet (m)
5

Figure 6.—Average sulfate concentrations at each sampling site. Negative distances on the x-axis

indicate sampling sites within Big Spring Cave.

Figure 7.—Average nitrate concentrations at each sampling site. Negative distances on the x-axis

indicate sampling sites within Big Spring Cave. Sulfate (mg L-1)

Distance from cave outlet (m)

Nitrate (mg L-1)

Distance from cave outlet (m)
6

We believe that organic carbon was not limiting in the cave

but rather was more abundant outside the cave. Bat guano is

believed to be a source of organic carbon inside and outside

(i.e., transported from inside to outside), while inputs of

organic matter from the surrounding forest vegetation and

litter layer contributed additional organic carbon outside the

cave. Five species of bats are known to inhabit Big Spring

Cave during at least part of the year (unpublished data), and

some bats use the cave year round.

In this region, inputs of SO4

 and NO3 from the atmosphere

are among the highest of those measured in the United

States (NADP/NTN 1987). Consequently, we hypothesized

that concentrations of these two ions might change with

distance from the cave. SO4

 in BSR increased significantly

(a=0.05), at an average rate of 0.0016 mg L-1 m-1, along its

length outside the cave (Fig. 6), while NO3

 decreased at an

average rate of 0.0013 mg L-1 m-1 in the resurgent portion of

BSR (Fig. 7).

The higher SO4

 concentrations in T1 and T2 (Fig. 6) were

similar to those in many nearby streams located in

sandstone and shale (Stephenson et al. 1995; Kochenderfer

et al. 1991). Thus, the Pocono formation appears to

substantially influence SO4

 concentrations in these two

tributaries. Also, the influence of the more acidic geology

downstream is evident in higher SO4 concentrations in T3

and Elklick Run (Fig. 6).

The decreases in NO3

 were surprising (Fig. 7) given the high

NO3

 deposition and additional organic-matter load available

outside the cave. The decrease in NO3

 in the resurgent waters

of BSR probably was due to progressive downstream

dilution.

Concentrations of NO3 are much higher within Big Spring

Cave and throughout BSR than in most streams in this area.

Generally, only streams also within the Greenbrier formation

have similar concentrations (Stephenson et al. 1995; Griffith

and Perry 1993). In fact, these concentrations are much

higher than what would be expected from inputs of

atmospheric deposition. Nor can they be explained by

geologic inputs since nitrogen compounds are negligible in

minerals. The primary source of NO3

 in these limestone

streams is believed to be bat guano, which has produced

high NO3

 concentrations in other cave-derived streams

(Hem 1970). While not all of the watersheds holding these

high NO3

 streams have caves, the groundwater chemistry in

many of these watersheds is similar because of the

continuity of the limestone formations.

Although high, NO3

 concentrations do not exceed the EPA

limit for safe drinking water (45 mg NO3

 L-1) (U.S. Environ.

Prot. Agency 1976). The NO3

 dilution that occurs

downstream further reduces potential effects of these high

concentrations on downstream water quality and water

usage.

Figure 8.—Average dissolved oxygen concentrations and water temperature at each sampling site.

Negative distances on the x-axis indicate sampling sites within Big Spring Cave. Dissolved oxygen (mg L-1)

Distance from cave outlet (m)

Temperature (oC)
7

The low NO3

 concentrations in T1 and T3 (Fig. 7) were more

typical of those in most of the other streams in this area.

Interestingly, although T2 surficially flows only through the

Pocono formation, its average NO3

 concentration suggests

that it is derived from a groundwater component influenced

by the upslope Greenbrier formation. Likewise, the relatively

high average NO3

 concentration in Elklick Run above the

confluence with BSR suggests that Elklick Run is similarly

influenced by the Greenbrier formation in its headwaters.

Literature Cited

Brady, N.C. 1984. The nature and properties of soils. New

York: MacMillian. 750 p.

Edwards, P.J.; Helvey, J.D. 1991. Long-term ionic increases

from a central Appalachian forested watershed.

Journal of Environmental Quality. 20: 250-255.

Edwards, P.J.; Wood, F. 1993. Field and laboratory quality

assurance/quality control protocols and

accomplishments for the Fernow Experimental Forest

watershed acidification study. Gen. Tech. Rep. NE-177.

Radnor, PA: U.S. Department of Agriculture, Forest

Service, Northeastern Forest Experiment Station. 15 p.

Griffith, M.B.; Perry, S.A. 1993. Colonization and processing

of leaf litter by macroinvertebrate shredders in streams

of contrasting pH. Freshwater Biology. 30: 93-103.

Helvey, J.D.; Hubbard, J.; DeWalle, D.R. 1982. Time trends

in pH and specific conductance of streamflow from

an undisturbed watershed in the central

Appalachians. In: Proceedings, Canadian hydrology

symposium; 1982 June 14-15; Fredericton, NB.

Fredericton, NB: National Research Council of Canada:

637-651.

Helvey, J.D.; Kochenderfer, J.N. 1987. Effects of limestone

gravel on selected chemical properties of road runoff

and streamflow. Northern Journal of Applied Forestry. 4:

23-25.

Hem, J.D. 1970. Study and interpretation of the chemical

characteristics of natural water, second edition.

Supply Pap. 1473. Washington, DC: U.S. Geologic Survey.

363 p.

Janzen, H.H.; Bettany, J.R. 1987. Measurement of sulfur

oxidation in soils. Soil Science. 143: 444-452.

Kochenderfer, J.N.; Edwards, P.J. 1991. Effectiveness of

three streamside management practices in the

central Appalachians. In: Coleman, S.S.; Neary, D.G.,

comps. Proceedings of the 6th biennial southern

silvicultural research conference. Volume 2; 1990 October

30-November 1; Memphis, TN. Gen. Tech. Rep. SE-70.

Asheville, NC: U.S. Department of Agriculture, Forest

Service, Southeastern Forest Experiment Station: 688-

700.

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Network. 1987. NADP/NTN annual summary:

precipitation chemistry in the United States. Fort

Collins, CO: Colorado State University, National

Resource Ecology Laboratory.

Reger, D.B. 1923. West Virginia geological and economic

survey–Tucker County. Wheeling, WV: [Name of

publisher unknown]. 542 p.

Stephenson, S.L.; Studlar, S.M.; McQuattie, C.J.; Edwards,

P.J. 1995. Effects of acidification on bryophyte

communities in West Virginia mountain streams.

Journal of Environmental Quality. 24: 116-125.

Stumm, W.; Morgan, J.J. 1981. Aquatic chemistry: an

introduction emphasizing chemical equilibria in

natural waters, 2nd ed. New York: John Wiley & Sons.

780 p.

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Protection Agency. 256 p.
Printed on Recycled Paper

Wooten, Alexander C.; Preer, James; Edwards, Pamela J. 1999. Geologic and

tributary influences on the chemistry of a headwater stream. Res. Pap. NE708. Radnor, PA: U.S. Department of Agriculture, Forest Service, Northeastern

Research Station. 7 p.

Water samples were collected weekly from June 12 to August 14, 1995, from Big

Spring Run (BSR) in West Virginia. BSR originates in Big Spring Cave, where three

stream samples were collected. In addition, 18 BSR sites were sampled downstream

from the cave, three from its tributaries, and one above and below the stream’s

confluence with Elklick Run. Along its length (653 m), the geology is Greenbrier

limestone in the headwaters, Pocono sandstone in the midsection and Hampshire

sandstone and shale in the downstream section. As a result, water chemistry was

strongly influenced by biogeochemical and hydrologic processes.

Keywords: Biogeochemistry, cavewater, cations, anions, pH

Online at: http://www.fs.fed.us/ne/newtown_square/publications/
Headquarters of the Northeastern Research Station is in Radnor,

Pennsylvania. Field laboratories are maintained at:

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Delaware, Ohio

Durham, New Hampshire, in cooperation with the University of New Hampshire

Hamden, Connecticut, in cooperation with Yale University

Morgantown, West Virginia, in cooperation with West Virginia University

Parsons, West Virginia

Princeton, West Virginia

Syracuse, New York, in cooperation with the State University of New York,

College of Environmental Sciences and Forestry at Syracuse University

Warren, Pennsylvania

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