FWS/OBS-80/40.17
October 1983
Air Pollution and Acid Rain
Report No. 17
ROCKY MOUNTAIN
ACIDIFICATION STUDY
Office of Research and Development
U.S. Environmental Protection Agency
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REPORTS ISSUED
FWS/OBS-80/40.1
FWS/OBS-80/40.2
FWS/OBS-80/40.3
FWS/OBS-
FWS/OBS-
FWS/OBS-
FWS/OBS-
FWS/OBS-
FWS/OBS-
FWS/OBS-
FWS/OBS-
80/40.4
•80/40.5
•80/40.6
80/40.7
•80/40.8
•80/40.9
•80/40.10
•80/40.11
FWS/OBS-80/40.12
FWS/OBS-80/40.13
FWS/OBS-80/40.14
FWS/OBS-80/40.1 5
FWS/OBS-80/40.16
FWS/OBS-80/40.1 7
Effects of Air Emissions on Wildlife Resources
Potential Impacts of Low pH on Fish and Fish Populations
The Effects of Air Pollution and Acid Rain on Fish,
Wildlife, and Their Habitats: Introduction
: Lakes
r Rivers and Streams
: Forests
: Grasslands
: Tundra and Alpine Meadows
: Deserts and Steppes
: Urban Ecosystems
Critical Habitats of
Threatened and Endangered Species
Effects of Acid Precipitation on Aquatic Resources:
Results of Modeling Workshops
Liming of Acidified Waters: A Review of Methods and
Effects on Aquatic Ecosystems
The Liming of Acidified Waters: Issues and Research -
A Report of the International Liming Workshop
A Regional Survey of Chemistry of Headwater Lakes and
Streams in New England: Vulnerability to Acidification
Comparative Analyses of Fish Populations in Naturally
Acidic and Circumneutral Lakes in Northern Wisconsin
Rocky Mountain Acidification Study
For sals by the Superintendent o! Documents, U.S. Government Printing Office, Washington, D.C. 20402
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UNITED STATES
DEPARTMENT OF THE INTERIOR
FISH AND WILDLIFE SERVICE
Dear Colleague:
The Eastern Energy and Land Use Team (EELUT) is pleased to provide you
this report on the evaluation of the sensitivity and potential effects
of acidic deposition in watersheds characteristic of the Rocky Mountain
Region. This report is part of the series of technical reports on air
pollution and acid rain developed at EELUT. Previous reports are listed
on the inside front cover.
Areas within Rocky Mountain National Park and Yellowstone National Park
were selected as representative of geologic types in a large portion of
that in the total Rocky Mountain Region. In addition to determining the
sensitivity of characteristic watersheds, the study also evaluates the
extent of current acidification, the impacts on fish populations, and
recommendations for assessment of future trends in both changing water
chemistry and fishery impacts.
Please feel free to send suggestions or comments on this report to EELUT.
Sincerely,
R. Kent Schreiber
Acting Team Leader, EELUT
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FWS/OBS-80/40.17
October 1983
Air Pollution and Acid Rain
Report No. 17
ROCKY MOUNTAIN ACIDIFICATION STUDY
by
1. J. H. Gibson
2. James N. Galloway
3. Carl Schofield
4. William McFee
5. Robert Johnson
6. Sandy McCarley
7. Nancy Dise
8. David Herzog
(See addresses on page ii)
Project Officer
R. Kent Schreiber
Eastern Energy and Land Use Team
U.S. Fish and Wildlife Service
Route 3, Box 44
Kearneysville, WV 25430
Cooperatively Produced For:
Research and Development
Eastern Energy and Land Use Team
and
Region 6, Habitat Resources
U.S. Fish and Wildlife Service
U.S. Department of the Interior
Washington, D.C. 20240
Fish and Wildlife Service
U.S. Department of the Interior
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DISCLAIMER
Although the research described in this report has been funded wholly or in
part by the U.S. Environmental Protection Agency through Interagency Agreement
No. EPA-81-D-X0581 to the U.S. Fish and Wildlife Service, it has not been
subjected to the Agency's peer and policy review and therefore does not neces-
sarily reflect the views of the Agency. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use by the
Federal Government.
1. J. H. Gibson 5.
Natural Resource Ecology Laboratory
Colorado State University
Fort Collins, Colorado 80523
2. James N. Galloway 6.
Dept. of Environmental Science
University of Virginia
Charlottesville, Virginia 22903
3. Carl Schofield 7.
Department of Natural Resources
Cornell University
Ithaca, New York 14853
4. William McFee 8.
Agronomy Department
Purdue University
West Lafayette, Indiana 47907
Robert Johnson
Earth Resources
Colorado State University
Fort Collins, Colorado 80523
Sandy McCarley
Versar Inc.
P.O. Box 1549
Springfield, Virginia 22151
Nancy Dise
Dept. of Environmental Sciences
University of Virginia
Charlottesville, Virginia 22903
David Herzog
1618 12th Avenue
San Francisco, California
94122
This report should be cited as:
Gibson, J.H., J.N. Galloway, C.
N. Dise, and D. Herzog. 1983.
and Wildlife Service, Division
Use Team, FWS/OBS-80/40.17, 137
Schofield, W. McFee, R. Johnson, S. McCarley,
Rocky Mountain Acidification Study. U.S. Fish
of Biological Services, Eastern Energy and Land
pp.
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EXECUTIVE SUMMARY
As a result of the growing concern for the potential effects of acid
deposition in western mountain watersheds, this project was undertaken to:
1. Determine the sensitivity of watersheds characteristic of the Rocky
Mountain Region and the relationship of watershed sensitivity to
geology and soils.
2. Evaluate the extent of current acidification and the potential for
increasing acidification with increasing deposition of nitrate and
sulfate.
3. Evaluate the results of the above in terms of impacts on fish popu-
lations.
4. Develop recommendations for assessment of future trends in both
changing water chemistry and impacts on fish populations.
Areas were selected for study which had minimal human impact and for
which the maximum amount of data on soils, geology and water chemistry already
existed. The Rocky Mountain National Park (RMNP) and Yellowstone National
Park (YNP) areas selected exemplified two different geologic types. The
geology of these areas is representative of a large portion of that in the
total Rocky Mountain region. In addition, data on precipitation chemistry
were available from the National Atmospheric Deposition Program (NADP) moni-
toring studies in the two parks. In Yellowstone National Park up to 30 years
of water chemistry data were available, along with information on geology and
soils. In Rocky Mountain National Park a lake and stream sampling program -was
conducted to collect the water chemistry information. Throughout the project
the relationship between water quality data and fish responses determined in
research studies in Scandinavia and eastern North America were relied upon to
assess potential impacts on fish populations.
RESULTS
The two parks represent a contrast in geologic materials; Rocky Mountain
National Park being primarily underlain by granite and Yellowstone National
Park by volcanic materials, although the geologic material in one watershed in
Rocky Mountain National Park (the Upper Colorado River Basin) is of volcanic
origin. The examination of the geochemistry of Rocky Mountain National Park
has shown that many areas in RMNP are sensitive to acidic deposition and that
this sensitivity is primarily determined by bedrock geology. In addition,
sensitivity varies inversely with elevation. The analyses show that water-
sheds underlain by granite and biotite gneiss and schist are equally
i i i
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sensitive to acidic deposition. The lakes and streams in these watersheds had
alkalinities <200 ueq/1. Waters at the higher elevations (>3300 m) were very
sensitive (alkalinity < 100 ueq/1). The Upper Colorado River Basin and the
Upper Fall River Basin contains tertiary intrusive rocks in their drainage,
resulting in low sensitivity (alkalinity >200 ueq/1). Waters in Yellowstone
National Park had alkalinities generally above 200 ug/1, with a few < 200 ug/1
on rhyolite or basaltic flows.
The analysis of sensitive aquatic systems have been extrapolated to the
Central Rocky Mountain Region by delineating areas underlain by granite
biotite gneiss and schist and similar gneisses and schists. Areas underlain
by these formations are classified as sensitive (alkalinity <200 ueq/1), lakes
and streams located at higher elevations (>3300 m) can be classified as very
sensitive (alkalinity < 100 ueq/1). Areas underlain by tertiary intrusive
rocks were classified as nonsensitive (alkalinity >200 ueq/1).
The Central Rocky Mountain Region is currently receiving precipitation
that is somewhat acidic (ave. annual pH = 5.0, NADP 1982). The analysis of
the data collected in RMNP shows that little, if any, acidification of lakes
or streams has occurred'; however, areas that are subject to periodic
deposition of pollutants during upslope air movements from population centers
such as Denver may be experiencing some acidification.
As stated, high-elevation lakes and streams in the Central Rocky Mountain
Region are very sensitive to acidic deposition. Much of the region is
underlain by rock with low buffering capacities that is covered by highly
permeable soils with low ion-exchange capacities. As in RMNP, high-elevation
lakes and streams in this poorly buffered region probably will become
acidified if acidic deposition increases to the level currently experienced in
the northeastern United States. An evaluation of the potential impact of
increased acidic deposition on specific lakes and streams would require a
drainage-by-drainage assessment, as local variability in bedrock, hydrologic
flow path, and soil development may have an overwhelming influence on
sensitivity.
With respect to fish population there is currently no evidence of chronic
acidification and thus no apparent impact on fisheries. However, the very low
base cation concentration observed in the headwater drainages of Rocky
Mountain National Park suggests extreme sensitivity to acidification. Fish
populations present in these low calcium waters may be particularly
susceptible to osmoregulatory stress from episodic acidification. The few
remaining native trout (Salmo cl^arki) located in the interior regions of the
Rocky Mountains persist only in small isolated headwater drainages. The
displacement of these rare and endangered genotypes to headwater drainages
also makes them most susceptible to potential acidification in these sensitive
habitats. Waters in volcanic areas such as Yellowstone National Park are
generally of high alkalinity and thus do not represent potentially sensitive
habitats.
RECOMMENDATIONS
It is recommended that long-term watershed studies be established at
several points in the Rocky Mountain region. Water samples should be analyzed
iv
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for major inorganic constituents, DOC, aluminum, alkalinity and total acidity.
In addition, surveys of water chemistry should be performed in other
mountainous areas, not only in the Rocky Mountain region but also in other
areas of the western United States. In addition, an effort should be made to
determine the rate of dry deposition of neutral salts, i.e., calcium sulfate.
Behavioral responses and immigration tendencies of S. clarki populations
exposed to episodes of acidification should be determined experimentally.
Potential for aluminum mobilization in the Rocky Mountain watersheds exposed
to increased acid deposition should be studied. Studies of winter-spring
water chemistry in headwater catchments should also include evaluation of the
movement of trout populations in response to chemical change. The potential
sensitivity to acidification of watersheds currently occupied by endangered or
threatened populations of S. clarki or of watersheds considered as potential
candidate sites for reintroduction should be determined and given special
consideration.
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CONTENTS
EXECUTIVE SUMMARY iii
FIGURES ix
TABLES xi
ACKNOWLEDGMENTS xiii
INTRODUCTION 1
ROCKY MOUNTAIN NATIONAL PARK 6
Introduction 6
Description of Study Watersheds 6
Lithologic Units 9
Sampling Scheme and Methods 11
Chemistry of Surface Waters 11
Soils and Surficial Materials 16
Results 18
Soils and Surficial Materials 18
Chemistry of Surface Waters 27
Discussion 27
Relationship of Surface Water Chemistry to
Atmospheric Deposition, Elevation and Soil
and Geology 27
Alkalinity (Sensitivity) of RMNP Lakes and Streams 48
Current Acidification Status of RMNP 48
Future Impacts of Acidic Deposition 54
YELLOWSTONE NATIONAL PARK 57
Introduction 57
Description of Geology 57
Determination of Surface Water Chemistry 59
Results and Discussion 61
Lake Alkalinities (Sensitivities) 62
Factors Influencing Alkalinity (Sensitivity) 68
Historical Changes in Surface Water Chemistry 70
Current Status and Future Trends in Surface Water
Chemistry 78
FISH POPULATIONS 82
Introduction 82
Assessment Approach 82
Results and Discussion 83
Fish Resources in Potentially Sensitive Areas of the
Rocky Mountains 83
Fisheries Management Policies in Potentially Sensitive
Areas 86
VII
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CONTENTS (Concluded).
Potential Impacts of Acidification on Fish
Populations 89
CONCLUSIONS 95
Introduction 95
Rocky Mountain National Park 95
Soils and Geology 95
Surface Water Chemistry 95
Yellowstone National Park 97
Effects of Current and Future Acidification Levels in Fish
Populations in Yellowstone and Rocky Mountain National Parks ... 97
Sensitivity Evaluation of the Central Rocky Mountain Region ... 98
RECOMMENDATIONS FOR RESEARCH AND MANAGEMEMENT 102
Introduction .......... 102
Rocky Mountain National Park and Rocky Mountain Region 102
Yellowstone National Park 103
Fishery Research and Management 103
REFERENCES 105
APPENDICES
A. Soil and Water Chemistry Sampling Site Maps, Rocky
Mountain National Park 113
B. Soil Laboratory Procedures, Profile Descriptions and
Chemical Analyses 118
C. Water Chemistry Data, Rocky Mountain National Park 124
D. Water Chemistry Data, Yellowstone National Park 133
vn i
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FIGURES
Number Page
1 Location of study areas, Rocky Mountain National Park,
Colorado 7
2 Conceptual behavior of Cn, C. and alkalinity
concentrations as a function of altitude 12
3 Distribution of pH values in the mineral soil and the
surface organic layer of all four watersheds 2.1
4 "Excess" base cations vs. silica for two sensitive
watersheds in RMNP 31
5 Graphs of Cl vs. elevation for subbasins in RMNP 33
6 Graphs of SO, vs. elevations for subbasins in RMNP 34
7 Graphs of N03 vs. elevation for subbasins in RMNP 35
8 Graphs of alkalinity vs. elevation for subbasins in
RMNP 37
9 Graphs of excess base cations vs. elevation for
subbasins in RMNP 38
10 Graphs of silicate vs. elevation for subbasins
in RMNP 39
11 Spatial distribution of sensitivity in RMNP 49
12 Status of 23 lakes in RMNP 54
13 Predictor nomographs projecting the best and worst-case
estimates of the effects of increased acidic deposition
on lakes in RMNP 56
14 Regional-geological map of Yellowstone National Park .... 58
15 Alkalinity map, Yellowstone National Park 63
16 pH map, Yellowstone National Park 65
17 Sulfate map, Yellowstone National Park 66
ix
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FIGURES (Concluded).
Number Page
18 Location of hot springs and geysers, Yellowstone
National Park 67
19 Alkalinity versus elevation, lakes draining rhyolite
bedrock, Yellowstone National Park 70
20 Historical chemistry comparisons, High and Crescent
Lakes 72
21 Historical chemistry comparisons, Grebe and Wolf Lakes ... 73
22 Historical chemistry comparisons, Ice and Crag Lakes .... 74
23 Historical chemistry comparisons, Cascade Lake 75
24 Chloride versus alkalinity, Yellowstone National Park
lakes 77
25 Sulfate versus alkalinity, Yellowstone National Park
lakes 78
26 Precipitation pH and sulfate concentration, Yellowstone
National Park, WY, 1980-1981 79
27 Cross-hatching shows area found barren of fishes by
Jordan in 1889, with the exception of sculpins in the
Gibbon River above Gibbon Falls 85
28 Indigenous distribution of Salmo clarki pleuriticus 91
29 Indigenous distribution of Salmo clarki stomias 92
30 Spatial distribution of sensitivity in the central
Rocky Mountain region: Colorado 99
31 Spatial distribution of sensitivity in the central
Rocky Mountain region: Wyoming 100
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TABLES
Number Page
1 Major bedrock units: Composition and relative
susceptibility to chemical weathering 10
2 Analytical techniques 15
3 Representative landform types (surface features
and/or materials) observed in research area 17
4 Seismic refraction data summary 19
5 Summary of soil properties at four locations in the
East Inlet Valley 22
6 Summary of soil properties at nine locations in the
Upper Colorado drainage 23
7 Summary of soil properties at sample locations in
the Fall River drainage basin 24
8 Summary of soil properties at sample locations in
Glacier Gorge Basin 25
9 Mean ionic concentrations in Rocky Mountain National
Park watersheds 28
10 Comparison of mean of uncorrected (U) and "excess" (E)
base cations 30
11 R-mode varimax factor matrix of chemical data for 88
lake and stream samples underlain by granite and biotite
gneiss and schist in Rocky Mountain National Park 41
12 R-mode varimax factor matrix of stream chemistry, % soil
organic matter, and % unreactive rock for 40 lake and
stream samples underlain by granite and biotite gneiss
and schist in Rocky Mountain National Park 43
13 R-mode varimax factor matrix of stream chemistry
for 33 lake and stream samples underlain by tertiary
intrusive bedrock in Rocky Mountain National Park 44
XI
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TABLES (Concluded).
Number
14 Discriminant analysis of surface water chemistry
from 117 lake and stream samples from Rocky Mountain
National Park ........................ 46
15 Reclassification results .................. 46
16 Comparison of Rocky Mountain National Park and
Hubbard Brook precipitation chemistry ............ 51
17 Calculation of acidification status for Rocky Mountain
National Park watersheds according to ion balance
considerations ....................... 52
18 Analytical methods, Yellowstone National Park ........ 61
19 Regional alkalinity of Yellowstone National Park
lakes ............................ 69
20 Relative concentration of alkalinity and sulfate,
lakes with historical data ................. 76
21 Sulfate levels in selected acidified waters ......... 80
22 Current and historical fish population status of
lakes and streams in Yellowstone National Park ....... 86
23 Total alkalinity and fish population status for
sensitive lakes in Yellowstone National Park ........ 87
24 Endangered and threatened Salmo genotypes in the
Rocky Mountain Region .................... 89
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ACKNOWLEDGMENTS
As in any project as extensive as the Rocky Mountain Acidification Study,
there are a large number of individuals who make invaluable contributions who
are not credited in the author list. Such contributions were critical to the
success of this study.
In particular, we wish to express our appreciation to Jill Baron of the
National Park Service Water Resources Field Support Laboratory for her
generous assistance in the field sampling program at Rocky Mountain National
Park (RMNP), and Robert E: Gresswell, fishery biologist with the U.S. Fish and
Wildlife Service, Yellowstone Fisheries Assistance Office at Yellowstone
National Park (YNP), for his assistance in data gathering and advice
throughout the project. Without his contributions we would not have been able
to evaluate the YNP data.
Another important contribution to the data collection was made by William
Locke of Montana State University, who provided information on soils on RMNP
and aided in the selection of sampling sites. We also wish to thank Dave
Stevens of RMNP and Wayne Hamilton of YNP, who facilitated our access to the
parks and to the available information on soils, geology and water chemistry.
We also wish to acknowledge the support for the project from the U.S.
Fish and Wildlife Service and Kent Schreiber, who provided the major funding,
and the National Park Service Water Resources Field Support Laboratory, and
Raymond Herrmann, who provided support for one of the graduate students.
Lastly, we wish to express our sincere appreciation to Janice Hill of the
Natural Resource Ecology Laboratory Publications Section and her staff, Katie
Curry, Kay McElwain and Susan Taylor for their efforts "beyond the call of
duty in organizing, typing and editing this report.
xm
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INTRODUCTION
Acid precipitation and its subsequent impact on aquatic and terrestrial
ecosystems is a matter of extensive research and debate in much of the
industrialized world in the northern hemisphere. Northern Europe, United
States, Canada, and Japan, have all experienced an increase in the acidity of
precipitation and in many of these areas this increase has been associated
with deterioration in aquatic and terrestrial ecosystems. The extent of this
deterioration and its relationship to acidic precipitation has been the
subject of considerable controversy. However, it appears clear at this time
that in the Scandanavian countries, and limited areas of northeastern U.S. and
eastern Canada, lake and stream acidification as a result of acidic precipi-
tation has been demonstrated beyond reasonable doubt. In addition, in many of
these areas there have been documented declines in fish populations associated
with the increase in acidity. Effects on terrestrial systems and their
association with acidic precipitation are less well established, but there do
appear to be declines in forest productivity in areas of Europe and north-
eastern United States that are correlated with atmospheric deposition. These
observations have spurred initiation of extensive research programs to
determine the relationship between acidic deposition and declines in the
productivity of terrestrial and aquatic systems (National Research Council
1981).
The emphasis of research to date has been in eastern North America, areas
of which now receive rainfall with an average pH of 4.1 or below along with
elevated levels of sulfate and nitrate (NADP 1980). In addition, areas in
which the most significant impacts of acidic deposition have been demonstrated
in aquatic systems are underlain by geologic material of low buffering
capacity. Such areas are found in eastern Canada and northeastern United
States. The combination of limited buffering capacity of soils and parent
materials and elevated levels of acid deposition have led to lake and stream
acidification, with subsequent effects on the biotic community. The effects
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on aquatic systems, particularly the decline in fish populations, has been the
most significant factor in encouraging governments and industry that we are
dealing with a serious problem which requires not only increased levels of
research, but also the development of policy to bring about reductions in
anthropogenic emissions of sulfur and nitrogen oxides.
While the emphasis in the eastern U.S. and Canada is understandable
because of the documented problems, in terms of both levels of acidic
deposition and impacts, it has been noted that the same conditions of
sensitivity exist in areas of the western United States including the Rocky
Mountains, the Sierras, Cascades, and other western ranges. These areas are
primarily of granitic bedrock, and the limited data available has shown that
the high elevation lakes and streams have sensitivities comparable to those in
the eastern United States and Canada. On the other hand, data from the
National Atmospheric Deposition Program (NADP) and other research has not
demonstrated that these areas are receiving precipitation with acidity
comparable to that of eastern North America. Preliminary data from NADP would
indicate that the pH of rainfall in the Rocky Mountain West is averaging 4.8
to 5.0, with a possibility that in some areas at higher elevations the pH may
be somewhat below these values. Precipitation with pH values below 5 would
generally be considered to be more acidic than normal. This raises the
question whether the most sensitive lakes and streams at the higher elevations
are being acidified. Because of the importance of these lakes as trout
fisheries and their aesthetic value to millions of visitors, it is important
to gain a better understanding of the current status of these lakes with
respect to buffering capacity and to assess the potential for acidification
and subsequent impact on fish populations. A survey of the literature
indicates however, that little water chemistry data are available for high
lakes (>2500 m) in the central Rocky Mountains.
The most extensive watershed study in this region has been at the Como
Creek watershed in the northern front range of the Colorado Rockies (Lewis and
Grant 1979). At least 150 weeks of consecutive stream and precipitation
chemistry data are available (Lewis and Grant 1979; Lewis 1982), and the first
report of acidic deposition in the Rockies was made at this site (Lewis and
Grant 1980). The alkalinity in the waters of Como Creek averaged 192 peq/l as
determined by potentiometric titration to pH 4 (Lewis and Grant 1979). Other
studies of high mountain lakes include those by Dodson (1981) in the Elk
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Mountains of westcentral Colorado. This area, located on the west slope of
the Continental Divide, is underlain by quartzite, siltstone, sandstone, and
shale (Harte et al. 1983). Dodson (1982) found these lakes to have low
alkalinity, 8 to 350 (jeq/1. A recent study by Harte et al. (submitted) in the
same area reveals alkalinities ranging from 8 to 250 peq/l with pH values of
5.9 to 7.88. Turk and Adams (1983) have carried out a study of the chemistry
of high-elevation lakes in the Flat Tops Wilderness area of western Colorado.
The bedrock in this area is predominantly basalt with some granitic outcrops.
Alkalinities in this region range from 70 to 1400 peq/l. In addition, data
from a lake survey of the Mount Zirkle Wilderness area by Turk (unpublished)
shows alkalinities ranging from 12 to 315 peq/l. The bedrock in this area is
primarily granite. In his study of the South St. Vrain Watershed in the Front
Range of Colorado, Thurmon (in press) found that alkalinities in the head-
waters averaged 82 peq/l. This area is underlain by silverplume granite and
biotite, gneiss, and schist.
These studies of water chemistry of headwater lakes and streams in the
Central Rocky Mountain Region have only recently been conducted. The lack of
historical data prevents the evaluation of any long-term trend in acidity.
Lewis and Grant (1979) reported an increase in stream hydrogen ion concen-
trations in the Como Creek watershed over a 150 week period. This record,
however, is too short to be considered evidence of increasing acidification.
Lewis (1982) reported an average decrease in alkalinity of 180 peq/l for 104
lower elevation lakes and streams surveyed by Pennak in 1938-1942, and
resurveyed by Lewis in 1979. Although Lewis attributed this loss to acidic
deposition, the concurrent increase in total dissolved solids (TDS) suggests
that hydrologic variability is responsible for this decrease in alkalinity.
In addition, a 180 peq/l loss of alkalinity is much greater than any
alkalinity loss observed in strongly acidified lakes in the northeastern
United States (Hendrey et al. 1980). Thus, no convincing evidence of
acidification in the Central Rockies has yet been presented, although several
areas have been shown to be potentially sensitive (alkalinities less than 200
peq/l) to acidic deposition. Also, none of the studies in the Rocky Mountain
Region to date have associated the current alkalinity and pH of high-elevation
lakes and streams with potential changes in the future'and subsequent effects
on fish populations.
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In general, the objective of this project was to provide an assessment of
lake and stream sensitivity of selected areas in the Rocky Mountain region and
to relate this to potential effects on fish populations. It was also felt
that by coupling water chemistry data with data on the geology and soils in
the sampled watersheds, that a relationship could be established between water
chemistry and geology and soils types and that this relationship could be
extrapolated to other areas of the Rocky Mountain Region. More specifically
the objectives were to:
1. Determine the sensitivity of watersheds characteristic of the Rocky
Mountain region and the relationship of watershed sensitivity to
geology and soils.
2. Evaluate the extent of current acidification and the potential for
increasing acidification with increasing deposition levels of
nitrate and sulfate.
3. Evaluate the results of the above in terms of effects on fish popu-
lations.
4. Develop recommendations for assessment of future trends in both
changing water chemistry and effects on fish populations.
The plan called for selecting areas for the study which had minimal human
impact and for which the maximum amount of data on soils, geology, and water
chemistry might already exist. The plan relied heavily on the established
relationship between water quality data and fish responses as determined in
research studies in Scandinavia and eastern North America. After considering
potential study sites available, two areas of different geologic type were
selected: Yellowstone National Park and Rocky Mountain National Park. The
geology of these areas is representative of a large portion of that in the
total Rocky Mountain Region. Another factor considered was that each of these
parks participated in the National Atmospheric Deposition Program (NADP)
precipitation chemistry monitoring network, and therefore had available the
necessary precipitation chemistry data to be used in the analysis of the
extent of acidification of the surface waters. The existence of information
on geology and soils in both parks, while incomplete, proved of considerable
value. In Yellowstone National Park, water chemistry data was available for
up to thirty years in some lakes. A single season of lake and stream sampling
was conducted in Rocky Mountain National Park to determine water chemistry.
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The first sections of the report begins with an evaluation of the
sensitivity of lakes and streams in Rocky Mountain National Park and
Yellowstone National Park. Sensitivity (alkalinity) is related to both soil
and bedrock influences, as well as elevational gradients. The following
section discusses the relationship of the water chemistry data to fish
populations based on currently available fisheries data. Conclusions and
recommendations are presented in the final two sections of the report.
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ROCKY MOUNTAIN NATIONAL PARK
INTRODUCTION
A discussion of the studies performed in Rocky Mountain National Park
(RMNP) is presented in this section of the Rocky Mountain Acidification Study
(RMAS) report. Rocky Mountain National Park is located in northcentral
Colorado along the Continental Divide. It has an area of 106,700 ha and
ranges in elevation from 2,329 m to 4,345 m. Approximately one-third of the
area and the 107 named mountains are over 3,353 m high. The mountain building
was accomplished by a regional uplift of Precambrian igneous and metamorphic
rocks during Late Mesozoic and Early Cenozoic time (Richmond 1974). Volcanic
activity has more recently altered the western side of the park. Alpine
glaciation during the Pleistocene formed characteristic U-shaped valleys,
steep-sided cliffs, and lateral moraines. Cirque lakes are common. These
geologic characteristics made this park an ideal site in which to evaluate
lake and stream sensitivity.
DESCRIPTION OF STUDY WATERSHEDS
Four watersheds were selected within the park boundaries in which to
conduct the studies. The geologic criteria used in selecting watersheds were
geologic control (bedrock and glacial erosion/deposition) as determined from
existing information, with attention being given to the representativeness of
selected watersheds to the Rocky Mountain region in general and RMNP in
particular. Climatic factors suggested the selection of watersheds on both
the east and west side of the Continental Divide. Access to these watersheds
by foot trail was also a consideration.
The specific watersheds selected for study were Fall River Basin, Glacier
Gorge Basin, East Inlet Basin and Upper Colorado River Basin (Figure 1).
Information on the bedrock geologic control of these watersheds is available
with the bulk of the data compiled on a 1:48000 scale map (unpublished) by W.
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UPPER COLORADO
RIVER BASIN
GLACIER GORGE BASIN
Figure 1. Location of study areas, Rocky Mountain National Park, Colorado.
Subbasins are (A) Roaring River, (B) Ypsilon Creek, (C) Upper Fall River, (D)
Tyndall Gorge, (E) Loch Vale, (F) Glacier Creek.
A. Braddock, University of Colorado, Boulder. There are also two pertinent,
unpublished theses (Abbott 1974; Shroba 1977).
The geology in RMNP is similar to about 70% of the mountainous areas
within the Rocky Mountain region. The most extensive geologic material
present in the Colorado Rocky Mountain region is Precambrian granites and
metamorphic rocks. These rock types are present in three of the four basins
selected for this study: Fall River, Glacier Gorge, and East Inlet Basins.
The fourth watershed, the Upper Colorado River Basin has as its major rock
-------
types Tertiary volcanics with intrusives of andesitic to rhyolitic composi-
tion. Glacial till also constitutes a major geologic material in all four of
the watersheds, but especially in the Fall River Basin.
Fall River, Glacier Gorge, and East Inlet Basins have tributaries
beginning at the Continental Divide at elevations above timber!ine. The
tributaries start in material that is predominantly rock talus with some
tundra vegetation present. Soil development above timberline is generally
weak thus making geologic control the most significant factor controlling
water chemistry. Most of the tributaries have as their source some type of
snow field, glacier or cirque lake.
The Upper Colorado River Basin watershed, with its bedrock of inter-
mediate to rhyolitic composition, intrusive and extrusive igneous rocks, has
approximately analagous geology to that present in the San Juan mountains of
southwest Colorado and the northwest section of Yellowstone National Park.
This area is the only section of RMNP where these geologic conditions exist.
These rock types contribute more in terms of buffering capacity to the soils
because of mineralogy and more rapid weathering.
The third broad type of geologic material, glacial deposits, is present
in all four basins with Fall River having the largest percentage. Glacial
deposits range from late moraines of up to 200 feet thick to thin veneers in
upstream regions. These deposits have a major bearing on the soils encoun-
tered as well as the general water quality. The morainal material in general
is coarse grained with abundant boulders, gravels and sands. This material is
well drained and thus water interacts not only with the soils developed on the
glacial deposits but also with the deposits themselves.
Another factor, climatic regimes, has profound influences on watershed
characteristics. It is noted that two watersheds, Fall River and Glacier
Gorge basins, are located on the east side of the continental divide, while
the other two watersheds, East Inlet and Upper Colorado River Basins are on
the west side of the divide. This provides a contrast in precipitation levels
and vegetation types, both major factors in soil development.
A bedrock and surficial geology map using a U.S. Geological Survey 7.5
minute quadrant topographic map was prepared for each watershed using
primarily existing data (Braddock, unpublished; Cole 1977; Abbott 1974).
Also, a map using the same base has been prepared showing the geomorphic
provinces in each watershed. The map of the geomorphic provinces (talus
-------
slopes, scoured bedrock, moraine veneer, etc.), shows the prime source of the
soils (parent material) that have developed in those provinces along with the
primary vegetation present (Locke, unpublished).
The four watersheds were subdivided on the basis of tributary drainage as
follows (Figure 1):
Glacier Gorge: Tyndall Gorge, Loch Vale, Glacier Creek
subbasins
Fall River: Roaring River, Ypsilon Lake, Upper Fall
River subbasins
, East Inlet: Not subdivided
Upper Colorado River: Box Canyon subbasin
Lithologic Units
Igneous and metamorphic rocks are present in the four watersheds and
range in age from Precambrian to Tertiary; the metamorphic rocks are confined
to the Precambrian. Unconsolidated materials of Quaternary age are abundant
in all basins. The major bedrock units exposed in the four watersheds are
(Abbott 1974; Cole 1977; O'Neill 1981):
Xqs: Biotite gneiss and schist
Xam: Amphi bolite
Xgg: Quartz diorite gneiss '
be: Boulder Creek granodiorite
Ysp: Silver Plume granite
PEa, PEab, PEap: Andesite flows, breccia flows, prophyry
Ngd: Granodiorite of Mt. Richtofen stock
Ngr: Granite of Mt. Cumulus stock
Nvr: Ash flow tuff
The mineralogical compositions of bedrock geologic units are summarized
in Table 1. Using the Goldich (1938) weathering sequence and the modal
percentages of the lithologic units, a suggested weathering stability
classification is shown. The susceptibility to chemical weathering increases
to the right. The classification is essentially based on the relative modal
-------
Table 1. Major bedrock units: Composition and relative
susceptibility to chemical weathering.
Minerals (by %)
Quartz
Mi croc line
Orthoclase
Plagioclase
Plagioclase type
Biotite-
Lithologic units
Ngr
Least
35
60
4
1
Ysp
weather
27
38
24
Olig.
7
be
ao I e - -
31
26
25
And.
15
Nvra
High
High
Minor
Minor
Ngd
10
32
40
And.
18
Xgg
30-65
7-40
10-30
15-35
Xqs
37
11
3
22
Olig.
18
PEa, PEab,
- - - Mos
None
Minor
Minor
High
And.
High
PEapa Xam
;t weatherable
7-10
20-40
Labr.
7-20
Hornblende
Magnetite
Cordierite
Accessory
20-60
5-30
.Determination of percentage by optical means was not possible. Rating based on known rock type.
Olig. = Oligoclase, And. = Andesine, Labr. = Labradorite.
-------
percentages of mafic minerals, hornblende and biotite, and plagioclase, as
these minerals are more susceptible to chemical weathering (Goldich 1938).
Some attention has been given to the physical stability of the rock, i.e.,
schistosity in the biotite gneiss and schist (Xqs). The location of the ash
flow tuff (Nvr) in the classification is questionable because of possible
influence of the moderately high temperature of formation and the glassy
matrix on weathering.
Of the four basins selected for study (two on each side of the
Continental Divide), three are dominated by metamorphic rocks and soils
derived from those rocks. The third is in a region of volcanic rocks typical
of a significant section of the Rocky Mountain region. The three basins
representing metamorphic materials differ in the percentage of glacial
deposits in the basin vs. the steep slope areas with either thin or no soil.
SAMPLING SCHEME AND METHODS
Chemistry of Surface Waters
Conceptual basis. The general objectives of the RMAS were to determine
the sensitivity of waters in the Rocky Mountain region to acidification by
acid precipitation and to determine whether this will have an impact on fish
populations. An earlier section of this report outlined the strategy for
selecting the sampling sites and described how existing geologic and soils
information had been used to select systems and subsystems in the Park that
are representative of the Rocky Mountain region. Lakes and streams in nine
large watersheds (four basins) were sampled on an elevational gradient. For
each subsystem, it was expected there would be an elevational trend in the
concentrations of the base cations (calcium, magnesium, sodium, and potassium)
because these ions are derived from terrestrial ecosystems by the process of
soil or parent material weathering. An elevational gradient in the concen-
trations of the acid anions (sulfate, chloride, and nitrate) was not expected.
This concept is illustrated in Figure 2, a theoretical illustration in which
concentration of the sum of base cations (Cn) and the sum of the acid anions
(Cfl) is plotted as a function of elevation. At the point where they
M
intersect, the system has lost all alkalinity and is about to develop strong
acidity. In the lower elevation areas where Cn is larger than C», there has
to be another anion for charge-balance considerations. In these systems, the
anion is bicarbonate, which is equated to alkalinity because of the absence of
11
-------
O)
d
c
~0
cr
(D
O
O
'E
cn
UJ
O
-z.
O
O
'B
++Al
w
ELEVATION (m)
Figure 2. Conceptual behavior of CB, C, and alkalinity concentrations as a
function of altitude.
Al and organic compounds that could contribute to the alkalinity. For the
higher elevations where CA are larger than Cn, there have to be other cations,
again for reasons of charge balance. The cations are hydrogen and aluminum.
By definition this region has already developed strong acidity. The effect of
increased atmospheric deposition of the acid anions SO,^, N(K and Cl
-1
will
cause the horizontal line of C. to move upward resulting in a larger number of
lakes at the lower elevations developing strong acidity. This suggests that
the most sensitive (lowest alkalinity) lakes will be at the watershed head-
waters.
The dotted line in Figure 2 is worthy of mention. At lower elevations
where soil development is more extensive, the process of sulfate adsorption
may remove atmospherically derived sulfur from the waters of the watershed.
One of the goals of this project was to determine the degree of sulfate
adsorption as a function of elevation. Therefore, if the elevational gradient
12
-------
for the acid anions, specifically sulfate, follows the dotted line, we will be
able to field test this by the determination of sulfate adsorption capacity.
This concept, relating the concentrations of various species to eleva-
tion, was the basis for devising the general water chemistry sampling plan.
Sampling plan. Water chemistry sampling within each sub-basin was
carried out in a one to four day period to reduce variation in hydrological
conditions. Samples were collected under base flow conditions, i.e., sampling
did not occur within 24 hours after rainstorms. Lake samples were collected
at each lake inlet, outlet, and center location. Stream samples were taken 25
meters below each confluence and at approximately 150 meter elevation
intervals. (Sample location maps are presented in Appendix A.) Stream
samples were collected in the middle of the stream under falling water, while
lake samples were taken 0.3 meters below the surface at the center of the
lake.
Two 250 ml samples were collected at each site in clean polyethylene
bottles. Each bottle had been washed with hot water and detergent, rinsed
five times with hot tap water and five times with deionized water. The
analysis of blank samples indicated no contamination from this cleaning
procedure. Each bottle was rinsed three times in situ with sample water
before filling. One sample was immediately preserved with reagent grade
chloroform for later base cation and acid anion analysis. The sample
identification number, location, date, and time of collection were printed on
the bottle and recorded in the field log book.
Conductivity and pH were measured in a separate aliquot of sample at the
site. Unpreserved 250 ml samples for alkalinity analysis were stored at 5°C
for one to two weeks before analysis. The preserved samples were analyzed for
chloride, nitrate + nitrite, sulfate, phosphate, silicate, calcium, magnesium,
sodium, potassium, and ammonium within two to three months after sample
collection. The pH of the stream waters was too high to include aluminum
analysis.
Field analyses. Conductivities were measured in the field using a
Beckman model RC-16C meter and a Yellow Spring conductivity cell (YSC model
3404). Corrections to 25°C were calculated according to Standard Methods
(A.P.M.A. 1976). Field pH measurements were taken with a Corning digital pH
meter and a Corning model 476182 pH electrode. The meter was periodically
calibrated with cold dilute, strong acids in the laboratory. Each measurement
13
-------
was preceded by a two point calibration using pH 7.00 and pH 4.00 buffer
solutions. Corrections for the temperature difference between the sample and
buffer were made using meter adjustments. Stream samples for the field pH
analysis were collected in polyethylene beakers from the center of the stream.
The pH was allowed to stabilize before a reading was taken in a quiecent
sample. Lake samples for the field analysis were collected in polyethylene
bottles and brought immediately to shore where pH and conductivity measure-
ments were taken. pH was also measured in the laboratory as part of the
alkalinity titration.
Laboratory analyses. Calcium, magnesium, sodium, and potassium were
analyzed by atomic adsorption spectroscopy using an instrumentation labora-
tories model 751 AA/AE spectrophotometer. Samples were spiked with a solution
of lithium and lanthanum to suppress ionization in the magnesium and calcium
analysis (E.M.S.L 1978). A standard curve consisting of one blank and five
standards was prepared between every 34 samples to check for drift. If
significant (>10%) drift had occurred, the samples were reanalyzed. The
instrument was recalibrated after every standard curve (Emmel 1977).
Sulfate, phosphate, nitrate, chloride, silicate and ammonia were analyzed
by automated wet chemistry using a Technicon II Auto-Analyzer. Sulfate was
measured using a modification of the Thorin technique developed by the
Norwegian Institute for Air Research. Phosphate and silicate were analyzed by
standard molybdenum techniques (T.I.S. 1973b; T.I.S. 1976b). Nitrate plus
nitrite was measured by the standard cadmium reduction technique (T.I.S.
1972), while ammonia was analyzed using an Indophenol Blue method (T.I.S.
1973a). Chloride was analysed using the standard ferricyanide method modified
for low levels (T.I.S. 1976a). In all of the wet chemical analyses, one blank
and six standards were run between every 33 samples.
Alkalinities were measured using a potentiometric method developed by
Gran (1952). A 50 ml sample was titrated with 0.010 N HC1 from pH 4.0 to pH
3.3. The Gran's function of this titration curve was extrapolated to an
endpoint to determine the sample alkalinity. A Fisher Accumet 420 pH meter
and a Corning model 476182 pH electrode were used for this titration. The
meter was calibrated with pH 4.0 and pH 7.0 buffers at the beginning and end
of each set of titrations. Both samples and buffers used were at room
temperature and air equilibrium. An initial air-equilibrium pH was recorded
before each titration.
14
-------
A summary of the analytical methods is presented in Table 2.
Quality control. The study followed the following protocol on quality
control.
1. Precision: To determine precision, 5% of all water-quality samples
collected were treated as replicates. The results demonstrated a
precision for all measurements of ±10%.
2. Accuracy: In the field, the accuracy of the field pH measurement
was assured by calibration of the electrode with standard buffers
before each measurement. The pH meter and electrodes were periodi-
cally calibrated with cold, dilute acid standards.
Table 2. Analytical techniques.
Measurement
parameter
Instrumentation
Technique Summary
Mg
Ca
Na
K
SO,
N0
NH
Cl
SiO
PO,
Instrumentation Laboratory Atomic
Absorption Spectrophotometer, Model 751
Instrumentation Laboratory Atomic
Absorption Spectrophotometer, Model 751
Instrumentation Laboratory Atomic
Absorption Spectrophotometer, Model 751
Instrumentation Laboratory Atomic
Absorption Spectrophotometer, Model 751
Scientific Instruments Model A200 with
custom-designed manifold
Scientific Instruments Model A200 with
stock manifold
Scientific Instruments Model A200 with
stock manifold
Scientific Instruments Model A200 with
modified manifold
Scientific Instruments Model A200 with
Auto-Analyzer with stock manifold
Scientific Instruments Model A200 with
Auto-Analyzer with stock manifold
Conductivity YSI model 3403 Cell, Beckman RC-16C meter
pH Corning Model 3 Meter with Corning Model 476182
combination electrode
Alkalinity Radiometer auto burette with Fisher Accumet
420 meter and Corning Model 476182
combination electrode
Lathanum added, aspirated in oxidizing
flame and read at 285.2 nm using
deuterium background correction
Lathanum added, aspirated in oxidizing
flame and read at 422.7 nm
Lithium added, aspirated in reducing
flame and read at 589.0 nm
Lithium added, aspirated in reducing
flame and read at 766.5 nm
Modification of the thorin technique
developed by the Norwegian Inst. for
Air Research (NILU)
Standard Cadmium Reduction technique
Standard indophenol blue technique
Standard ferricyanide method modified
for low levels
Standard molybdenum blue technique
Standard molybdenum blue technique
Standard procedure
Standard two-point calibration with
pH 7.00 and pH 4.00 buffers
Air-equilibrated Grans titration
15
-------
The water-chemistry laboratory at the University of Virginia used two
techniques to determine the accurary of analytical measurement. Standard
additions were performed on representative samples. In addition, interlabora-
tory calibration with EPA (1982) and USGS (1981) was conducted by the analysis
of blind replicates for all ions. The results of these procedures showed that
the accuracy of the analytical measurements was ±10%.
Soils and Surficial Materials
William Locke (unpublished) has produced a general map of major soil
(landform-vegetation) groups in Rocky Mountain National Park which was
available for our use. Within each basin six to sixteen sites, representative
of the major soil groups and providing an altitudinal cross section, were
selected for soil sampling (see Appendix A map). With the aid of Locke, soil
pits were prepared and a soil-sampling scheme devised.
Soil samples were collected by excavating soil pits by hand to a maximum
depth of 50 cm. Samples weighing 300 g to 700 g of each soil horizon exposed
were collected and described. These samples were assumed to be representative
of the soils encountered in the different landform types in the study area.
Representative specimens of rock types were collected and identified.
Rock-type names conformed to those used in the Park by Abbott (1974), O'Neill
(1981) and Braddock (unpublished).
A complete sample description included colors, texture, structure,
rooting depth, and estimates of coarse material. Slope, size of area, and
surrounding vegetation was also recorded along with photographs of the sites.
Approximately 80-90 samples were collected during the 1981 field season.
Air dried soil samples passed through a 2 mm sieve were used in all
laboratory analyses. (The procedures used are described in detail in
Appendix B). Briefly, they were as follows: pH was determined in a 1:1 soil
water suspension. Exchangeable bases were extracted with 1 N NH4Ac and
determined by Atomic Absorption Spectroscopy. Extractable acidity was
determined using a BaCl2-Triethanolamine solution at pH 8.0, followed by a
titration. Cation exchange capacity was determined by the sum of exchangeable
bases and extractable acidity. Organic matter was estimated by loss on
ignition at 500°C and by wet oxidation in K2Cr20?-H2S04 solution (Mebius
method). Percent sand, silt, and clay was determined by the pipette method
after dispersion in sodium metaphosphate solution.
16
-------
Selected samples were tested for sulfate absorption by equilibrating 10
grams of soil with 25 ml of dilute ICSC* solution at a pH of approximately
4.1. The solutions were initially at 1, 5, and 10 mg of soil per liter.
After shaking with soil and separation by filtration, solutions were analyzed
for sulfate loss.
Parent and surficial materials. Determination of the parent materials of
the soils was accomplished by geologic reconnaissance of the area adjacent to
each soil sample and by binocular microscope examination of the 2- to 4-mm
fraction of each soil sample. Glacial till is the parent material for most of
the soil samples analyzed and, in turn, is derived from the geologic units
upvalley. Therefore, the composition of the 2- to 4-mm fraction of the soil
samples is representative of both the glacial till and its parent material,
the bedrock units in the area. The area! extent of mapped geologic units,
surficial and bedrock, in each basin was determined using a planimetric
digitizer and geologic maps. Weathering characteristics of the various
bedrock and surficial materials were studied, since they directly affect the
type and amount of soil present.
Landform types (Table 3) are helpful in determining the parent material
of the soils developed, the thickness of overburden and the existing vegeta-
tion. They convey surface features and materials, along with associated
vegetation that characterize mappable areas. This information can be obtained
Table 3. Representative landform types (surface features and/or materials)
observed in research area.
Exposed bedrock Moraine veneer
Talus slope Wet meadow
Unglaciated regolith Dry meadow
Moraine-ground Wet tundra
lateral Dry tundra
end
17
-------
by analysis of aerial photographs. Stream gradients for all rivers and
streams studied were determined with a linear digitizer.
Seismic refraction surveys were conducted at seven sites to determine the
thickness and types of surficial materials overlying bedrock. A Nimbus ES-125
single-channel signal-enhancement seismograph was used. The surveys were made
in coniferous forests on moraine veneer, wet meadows and dry meadows. The
seismic velocities obtained permitted grouping of geologic materials into four
categories: soil, alluvial deposits, glacial till, and bedrock. Numerous
factors influenced these values. They include thickness of organic material,
water content, clay content, percent of boulders, lithologic makeup of glacial
till and type and degree of weathering and/or jointing of bedrock.
RESULTS
Soils and Surficial Materials
Characteristics. The seismic analysis revealed that generally, all soils
had velocities corresponding to moist, loamy or silty soils, as reported by
Redpath (1973), which indicate a low clay content. The glacial till
velocities correspond to values obtained by Redpath (1973) for dry glacial
moraine deposits in the Sierra Nevada of California. These deposits had low
clay content similar to those encountered in the RMNP project area. Most
bedrock velocities were low, indicating a fairly large degree of weathering
and/or jointing. This suggests that surface water penetrates to considerable
depth.
Seismic profiling revealed the thickness of the soils to be in the range
of 0 to 1.9 m; alluvial materials, 3.0 to 3.7 m; and the glacial till, 0 to
7 m (Table 4). The high values represent materials in the center of the
stream valleys with decreasing thickness up the sideslopes. Although these
depths are not large by comparison with nonalpine surficial materials, they
could be quite adequate for buffering of acid precipitation if sufficient clay
and organic material existed. Stream gradients are generally indicative of
the landform type and are easily obtainable from topographic maps. The
steepness of gradient generally is indirectly proportional to the thickness of
both glacial and alluvial overburden in the terrain encountered.
The soils tend to be coarse, stony, and shallow with very little evidence
of formation of secondary minerals or eluviation. (A detailed description of
the soil characteristics of each sampling site may be obtained from the
18
-------
Table 4. Seismic refraction data summary.
Profile #
1
2
3
4
5
6
7
Soil
Velocity (m/s)-
thickness (m)
396-0.7
215-1.4
224-0.8
374-1.9
None present
326-1.5
318-1.7
Glacial or
alluvial3
Velocity (m/s)-
thickness (m)
1699-5.5
1390-6.2
1117-3.8
None present
955-3.2
1594-5.3
None present
Bedrock
Velocity
2417
3135
2391
3941
3758
3208
2989
Landform type
Moraine veneer
Dry meadow
Wet meadow
Moraine veneer
Wet meadow
Moraine veneer
Moraine veneer
Unconsolidated parent material underlying soil.
-------
author). Slight development of a color B horizon was detectable in a few of
the lower elevation soils developed in glacial till. The major variation in
soils within the study area was caused by thickness of deposit, depositional
mechanism (local alluvium, till or colluvial deposit) and amount of accumu-
lated organic matter. Differences in mineralogy of the parent material was
not evidenced in soil chemical or physical properties. Elevation, especially
as it relates to vegetative cover, appears to be important in determining the
organic matter content.
Coarse materials (>2 mm dia. ) comprised much of the soil volume in most
locations. Some of the meadows, however, were essentially stone-free. The
talus slopes and most other locations had soils with 10 to 85% coarse
fragments in the samples collected. The collection process itself was biased
against large fragments therefore the percentages are conservative.
In general the percent base saturation and pH of both the organic layers
and mineral soil are low. All pH values are acid, in the range 4.2 to 5.6,
with occasional values as low as 3.5 and as high as 6.8. The basic cation
status of these soils is generally quite low due to the scarcity of basic
rocks in the underlying material. The % base saturation of the soil exchange
complex ranges from as low as 2% upwards to 90%, but very few samples exceed
70%. The average for each of the basins ranges from 24 to 48%.
The pH occurring most often in the mineral soil horizons was 5.2 with a
strong central tendency around 5.2. In 15 of the 30 locations the mineral
soil pH in the top 50 cm was within the range 5.0-5.3 (Figure 3). The surface
organic layers had a pH range similar to the mineral soils, but the distribu-
tion was shifted slightly toward more acid values.
The clay content of these soils was low. Only two sample locations
contained horizons with more than 20% clay (% of <2 mm fraction). It is
apparent that most of the exchange capacity is provided by the organic matter.
Clay mineralogy was not determined in these samples, but the residual CEC
which appears to be due to the clay after subtracting the CEC commonly
associated with the organic fraction, indicates a material high in CEC such as
vermiculite. Shroba (1977) reported mica alteration and formation of 10-18A
mixed layer clays in Alpine soils and more extensive alteration and the
presence of vermiculite in the spruce-fir region in the Rocky Mountains.
Sampling of soils was limited to a few locations within each watershed.
The variability within watersheds was great and masks many differences that
20
-------
10
oo
1 i 1 Q
D_
n K vn n
5.2- 5.4- 5.6- 5.8- 6.0- >6.1
PH
Figure 3. Distribution of pH values in the mineral soil and the
surface organic layer of all four watersheds.
may exist between drainage basins (Tables 5 through 8). Fall River basin
(Table 7) contained the only soil samples with pH in excess of 6.0. These two
mineral soil samples were from the lowest elevations sampled in this study.
As a result, the average soil pH in that basin was higher than that in the
other three. Otherwise, the average pH in Fall River basin would have been
5.3, essentially the same as those in Upper Colorado and East Inlet basins.
The samples collected in Glacier Gorge Basin (Table 8) are the most acid.
Only one mineral soil sample exceeded a pH of 5.2. The mean of all 10 samples
in that basin was 5.0, relatively acid for young soils.
The pH of surface organic layers in each basin was usually slightly lower
than the mineral soil underneath it. This is a common occurrence in soils
with a surface accumulation of organic material under coniferous forests.
A cross section of soil samples were selected for determination of
sulfate absorption capacity which can contribute greatly to a system's
resistance to the impact of acidic inputs. Sixteen soil samples were tested
at 1, 5 and 10 ug S/ml solution for their ability to adsorb sulfate. None of
the samples tested removed detectable quantities of sulfate from solution at
any of the three concentrations. In many cases the soils released low amounts
of sulfate to the solution. This was probably released from the organic
matter as a result of the sample drying and rewetting and microbial activity
during storage and processing. (Samples for sulfate retention determinations
should be stored moist at 0° C until the test is performed.) Based on these
21
-------
Table 5. Summary of soil properties at four locations in the East Inlet Valley.
ro
ro
Location
El 5
El 3
El 2
El 1
X
Elevation
1000 m
2.90
3.11
3.17
3.35
Mineral soil (0-50 cm)
Org %
5
2
8
6
pH
5.5
5.9
4.8
5.1
5.3
CEC %
27
15
34
16
BS %
47
69
9
23
37
Surface organic
Clay % Org %
22 61
14 57
5 48
8
pH
5.0
6.0
4.7
—
5.2
Vegetation
type9
F
F
M
G
For location see designation on maps Appendix A.
-------
Table 6. Summary of soil properties at nine locations in the Upper Colorado drainage.
rv>
CO
Location
SG-3
D-l
BX-1
HG-2
SG-2
MN-2
HG-1
MN-1
SG-1
X
Elevation
1000 m
3.05
3.14
3.17
3.20
3.23
3.32
3.32
3.35
3.47
Org %
3
8
4
2
2
2
2
4
3
Mineral
PH
4.8
5.6
5.1
5.1
5.2
4.8
5.8
5.5
5.2
5.2
soil
CEC %
20
39
22
20
16
16
17
16
22
(0-50 cm)
BS %
12
50
21
4
25
22
45
33
44
28
Clay %
14
—
16
13
13
—
—
7
19
Surface
Org %
38
31
38
52
31
—
—
—
—
organic
PH
4.7
5.4
5.3
3.5
5.2
—
—
—
—
4.8
Vegetation
type3
F
F
F
F
M
F
T
T
T
?F = coniferous forest, M = wet meadow, G = grass, T = talus slopes with scattered grasses.
For location see designation on maps Appendix A.
-------
Table 7. Summary of soil properties at sample locations in the Fall River drainage basin.
Location
L 81-18
L 80-6
L 80-1
YCS-1
81-13
81-16
80-11
80-13
X
Elevation
1000 m Org %
2.62 6
2.65 <1
2.68 <1
3.08 <1
3.20 1
3.23
3.57 <1
3.66 4
Mi
PH
6.1
6.6
5.3
5.2
5.3
—
5.5
5.0
5.6
neral soil (0~50
CEC
(meq/100 g)
16
3
2
6
11
—
8
14
cm)
BS %
56
85
52
30
25
—
68
23
48
Clay %
6
6
4
4
7
4
7
Surface organic Vegetation
Org % pH type3
F
G
29 5.9 F
F
F
60 4.8 M
T
21 4.8 G
5.1
^F = coniferous forest, M = wet meadow, G = grass, T = talus slopes with scattered grasses.
For location see designation on maps Appendix A.
-------
Table 8. Summary of soil properties at sample locations in Glacier Gorge Basin.
in
Location5 E]^tion
1000 m
GC-4
TG-4
GC-3
TG-3
AC-3
TG-2
GC-2
GC-1
AC-1
TG-1
X
2.80
3.08
3.08
3.14
3.20
3.35
3.41
3.44
3.47
3.51
Mineral soil (0-50 cm)
Org %
1
5
3
1
5
9
4
2
13
7
pH CEC
(meq/100 g)
5.1
5.0
4.6
5.2
5.1
4.3
5.2
5.2
4.4
5.8
5.0
8
26
12
17
20
48
9
4
32
19
20
BS %
20
1
2
39
14
15
39
37
16
52
24
Clay %
9
19
9
7
6
10
3
3
16
7
Surface organic Vegetation
Org % pH type3
65 4.9 F
25 4.6 F
62 4.3 F
j
65 5.5 M
55 5.2 G
46 5.1 M
T
G
T
4.9
, F = coniferous forest, M = wet meadow, G = grass, T = talus slopes with scattered grasses.
For location see designation on maps Appendix A.
-------
tests, it is obvious that these soils have very little if any sulfate absorp-
tion capacity at S concentrations up to 10 pg S/ml at a pH of 4.1.
Soil buffering capacity. The soils of the Rocky Mountain National Park
at the higher elevation (above 2800 m) are only slightly developed. They have
surface organic horizons in some cases and usually have a darkened A horizon
underlain by slightly weathered material derived from granites, diorites and
other rocks low in bases. The soils are coarse, low in clay, low in basic
cations and relatively acid (modal pH 5.2). The organic matter provides most
of the cation exchange capacity and there is no evidence of sulfate adsorption
capacity.
The physical properties of these soils—coarse, high in sand, low in clay
and steeply sloping—promote rapid movement of water to the streams and lakes.
Residence times of water will tend to be short especially at the higher
altitudes where there is less vegetation, thinner soils and less accumulated
organic matter. Much of the water flow will be rapid and through coarse
channels such that only a small percentage will approach equilibrium with the
soil materials.
The chemical properties, low base saturation, low pH, and low cation
exchange capacity provide little opportunity for neutralizing acidic inputs or
providing significant alkalinity to the water system. If acidic deposition in
the region reached pH values in the low 4.0s there would be a potential for
the soil to buffer the pH upward slightly. However, since most water moving
through these coarse soils will not have a residence time sufficient for
equilibration with the soil, there would be little effect on acidity. The
current situation with the soils more acid than the streams indicates that the
soils are not controlling the aquatic system pH. Since the dominant soil pH
is only slightly above 5 and the exchangeable basic cation supply is low,
these soils would not be expected to provide strong buffering of the ecosystem
against acidification.
Even though aluminum was not determined in this study the present pH of
these soils indicates that aluminum concentrations in the soil solution are
not high. A lowering of soil pH to 4.5-4.6 would cause a significant increase
in aluminum in soil solution. Some additional aluminum would reach the
aquatic system, but much more information would be needed to quantify the
expected change in aluminum.
26
-------
The soil properties already mentioned plus the absence of sulfate absorp-
tion capacity indicate that these soils should be considered in a "sensitive"
category. They are among the soils which have low capacity to absorb and
neutralize acidity and therefore the associated aquatic systems would not be
protected from pH change by the soil ecosystem (Galloway et al. 1983). The
soil itself is probably resistant to rapid acidification. The abundance of
relatively unweathered minerals provides the soil's major buffering against
lowering of the pH much below its present values.
Chemistry of Surface Waters
The lakes and streams in RMNP are characterized by low ionic strength.
An average concentration for the inorganic constituents are presented in
Table 9. The raw data for all of the measured constituents of the more than
150 samples are presented in Appendix C, along with sampling dates for each
subbasin. On an equivalent basis, the relative concentrations of the base
cations are Ca»Na>Mg»K for most of the watersheds, although magnesium
concentrations are greater than sodium in the Upper Colorado and Upper Fall
River Basins.
The Ypsilon Creek, Tyndall Gorge, Loch Vale, and Glacier Gorge subbasins
had similar stream chemistry. These watersheds are characterized as having
lower alkalinity and base cation concentrations than the rest of the study
area. Roaring River and East Inlet had slightly higher alkalinity, base
cation, and silica concentrations. The Upper Fall River Basin had signifi-
cantly higher concentrations of these constituents, while the Upper Colorado
River Basin had the highest alkalinity, base cation, and sulfate concentra-
tions of any of the watersheds.
DISCUSSION
Relationship of Surface Water Chemistry to Atmospheric Deposition,
Elevation, Soils, Surficial Materials and Geology
Calculation of "excess" cations. The streams and lakes of RMNP have very
low cation and anion concentrations. In the watersheds underlain by granitic
and metamorphic rock, the average Cn (Na + K + Mg + Ca), is only ^85 ueq/1
(Table 9). In such dilute waters, the atmospherically deposited base cations
may comprise a significant fraction of the stream water cation concentration.
Previous researchers have corrected surface water chemistry data for the
27
-------
Table 9. Mean ionic concentrations in Rocky Mountain National Park watersheds.
Watershed
Roaring River
Ypsilon Creek
Upper Fall River
Andrews Creek
ro
00 Loch Vale
Glacier Creek
Upper Colorado
River
East Inlet
PH
6.9
6.6
7.1
6.5
6.0
6.6
7.5
6.8
Alk
74.4
48.0
180.5
38.8
41.2
40.3
331.8
85.5
Na
29.0
22.9
40.2
16.1
15.0
14.2
34.6
26.5
K
3.6
4.1
7.5
3.7
3.1
3.0
7.6
2.5
Mg
21.7
15.2
67.3
13.1
13.9
10.0
80.0
16.0
Ca
66.5
43.6
106.9
55.7
52.9
46.3
234.3
90.0
NH4
0.1
0.1
0.1
0.0
0.4
0.1
0.3
0.1
Cl
6.0
3.4
7.9
3.7
4.5
3.1
7.9
4.2
N03
8.3
9.8
4.9
12.5
17.1
11.3
6.3
5.6
so4
34.7
30.2
46.3
32.3
28.2
13.3
84.3
35.7
Si04
68.8
61.3
110.8
36.5
33.3
32.8
81.5
67.9
CA
123.4
91.4
239.6
87.3
91.0
68.0
430.3
131.0
CB
121.0
86.2
222.0
88.9
86.2
73.8
357.1
125.5
aAll concentrations are in |jeq/l, except SiO., which is in pM/1.
-------
atmospherically deposited base cations by substracting the "seasalt" contribu-
tion (Henriksen 1980; Aimer et al. 1978). Although RMNP does not receive sea
salt in its precipitation, the evaporite basins and arid regions upwind of the
park result in the wet and dry deposition of base cations in the form of dust
and salts (Gosz 1975). In an effort to separate "excess" cations (those
released as a result of acid buffering reactions) from atmospherically
deposited cations, we have made a correction for atmospheric deposition.
Chloride, a conservative element with no terrestrial source (i.e., not present
in the bedrock) is used to make this correction. The calculation is made by
subtracting from each cation concentration the product of the chloride
concentration at that sample site and the ratio of that element to chloride in
precipitation (NADP 1982). The result is the precipitation corrected or
"excess" concentration-e. g. , Na* = Na - (Cl x Naprecip_ )/Clprecip_ (*
indicates "excess" concentration). Some base cations, especially potassium,
are taken up by the ecosystem. As a result, our precipitation-corrected
concentration of this element may turn out to be negative. If the calculation
results in a negative value for an element, the precipitation-corrected
concentration is taken as zero. The results of these calculations are
presented in Table 10. This method of calculating the "excess" base-cation
concentration (Na* + K* + Mg* + Ca* = CR*) is a correction for the maximum
contribution of C, (Na + K + Mg + Ca = CR) by wet deposition.
The stochiometry of primary dissolution reactions provides a check on
this correction, since the release of base cations by mineral dissolution is
accompanied by the concurrent release of HLSiO,, e.g.:
NaQ 7CaQ gA^ 3Si'2 ?08 + 3.45 H20 + 1.3 H2C03 = 0.65 Al2Si205(OH)4
(oligoclase) (kaolinite)
+1.4 H4Si04 +0.7 Na+1 +0.3 Ca+2 +1.3 HCO"1
3 K2(Mg3Fe3)Al2Si6020(OH)4 + 24 H20 + 18 H2C03 =
(biotite)
2(Mg3Fe3)Al3Si5020(OH)4-8 H20 + 6 K+1 + 3 Mg+2 + 3 Fe+2 + 8 H4$i04 + 18 HCO'1.
(vermicullite)
29
-------
Table 10. Comparison of mean of uncorrected (U) and
"excess" (E) base cations.3
Watershed
Roari
Ypsil
Upper
ng River (U)
(E)
on Creek (U)
(E)
Fall River (U)
(E)
CB
121.
72.
86.
56.
222.
155.
0
3
2
2
0
,2
Na
29.
21.
22.
18.
40.
30.
K
0
9
9
8
?
7
3.
0.
4.
0.
7.
0.
.6
0
.1
3
,5
,0
Mg
21.
11.
15.
9.
67.
53.
7
7
2
4
3
8
Ca
66.
39.
43.
28.
106.
71.
5
3
6
2
9
2
Andrews Creek (U)
(E)
Loch Vale (U)
(E)
Glacier Creek (U)
(E)
Upper Colorado River (U) 357.1 45.6 7.7 77.8 218.1
(E) 280.1 35.1 1.4 63.0 181.0
88.9
57.3
86.2
47.9
73.8
47.6
16.1
11.9
15.0
9.6
14.2
10.5
3.7
0.0
3.1
0.3
3.0
0.2
13.1
7.3
13.9
6.1
10.0
4.8
55.7
38.1
52.9
32.4
46.3
32.5
East
Inlet
(U)
(E)
125.
91.
5
5
26.
22.
5
5
2.
0.
5
0
16.
8.
0
8
90.0
60.6
aAll concentrations in peq/1.
We can assess the accuracy of our estimate of CR* by comparing the corrected
-4 ° -A
CB* to silica concentrations (as moles of SiO, ). Graphs of C * vs. SiO, for
Loch Vale and Ypsilon Creek watersheds, with low intercepts show that our
correction is appropriate for the watersheds with lowest alkalinity (Figure
4). The variation in the slopes of the regression lines among the watersheds
reflects a difference in the distribution of minerals. Watersheds with a
slightly greater percentage of biotite will have larger slopes than those with
more oligoclase in their drainage according to the different stochiomatry of
the weathering reactions. This check on our calculation of CD* is not
D
30
-------
100 —\
YPSILON CREEK
-
1 58-
-x m
o
0
(
9-
Px o
Q-'O
X*0
\ \ \ \ ' \ \ i
3 50 1C
SiO, (yM/1)
6.25 + 0.92 SiO.
75
100 —1
50 —
LOCH VALE
O'
0
V
'o
0
-0.05 + 1.32 SiO,
IT = 87
(
1 1
)
1 1
5
0
T~l 1
ie
Figure 4. "Excess" base cations vs. silica for two sensitive
watersheds in RMNP.
appropriate in watersheds where nonsilicious minerals and soil cation-exchange
reactions play a large part in the geochemistry (i.e., the Upper Colorado
River and parts of the Fall River basins).
Atmospheric deposition and water chemistry. Researchers have shown that
the predominent direction of air mass movement over the Front Range of the
Central Rocky Mountains is from west to east (Barry 1973), with periodic
31
-------
upslope movement from the east (Kelley and Stedman 1980). Although most of
the precipitation received by this area is dropped by the westerly air masses,
the upslope transport of pollutants from sources to the east may have a
profound influence on the deposition chemistry of the Front Range (Kelley and
Stedman 1980). The atmospheric deposition from the westerly air masses
contains little sea salt (Junge and Werby 1958) but does result in the wet and
dry deposition of airborne dust and salts from the dry, windy areas to the
west (Gosz 1975). As a result, RMNP precipitation has a relatively high base
cation concentration [22.0 p.eq/1 Ca in RMNP, compared with 13.0 ueq/1 in the
Adirondacks (NADP 1982, Altwicker and Johannes 1980)].
The nitrate concentrations in RMNP are relatively high, comprising 35.6%
of the acid anions in precipitation, compared with 28.7% at Hubbard Brook
(NADP 1982). These high nitrate concentrations are probably the result of
upslope transport of NO from the Denver metropolitan area (Kelley and Stedman
/\
1980). The bedrock in RMNP contains only trace amounts of chloride (Levering
and Goddard 1950), while sulfur-bearing minerals (e.g., chalcophyrite and
gypsum) are found only in the Upper Fall River and Colorado River basins. As
a result, atmospheric deposition is expected to be the primary source of
chloride and nitrate in all of the streams in RMNP, as well as the primary
source of sulfate in the waters of East Inlet, Glacier Gorge, Ypsilon Creek,
and Roaring River.
Stream water chloride and nitrate concentrations are fairly uniform over
the park, although East Inlet, on the west side of the continental divide, has
lower nitrate concentrations than the other four watersheds (Table 9). Two
plausible explanations for the lower nitrate in East Inlet are (1) less
deposition from upslope air masses bearing NO from the Denver area and/or (2)
/\
more biological activity. Chloride and sulfate concentrations show little
variability with elevation, indicating negligible variation in the atmospheric
contribution of elements with elevation (Figures 5 and 6). Nitrate, the most
biologically active anion, shows some variation over elevation, with the
highest nitrate concentrations above the timberline, where biological activity
is lowest (Figure 7).
Streamwater chemistry and elevation. Elevation is related to several
parameters that may effect streamwater chemistry. The thickness of surficial
deposits (glacial till, alluvium, loess, and soils) and the length of flow
path increase with decreasing elevation as we descend from headwater lakes
32
-------
50 —i
cr
0)
3-
e
ROARING RIVER
O °(S>0 ^00
\\ iii i i i i i i i
2500 3800 3500 4000
ELEVATION (m)
50 —i
CT
01
3.
UPPER FALL RIVER
O
o
8500
i i i i r i i T i i
3000 3500
ELEVATION (m)
4000
50 —
0
GLACIER CREEK
^ Q o o o
o
i i i i i i r i n i
2750 3000 3250
3500
ELEVATION (m)
50-
CT
0)
50-
CT
0)
3.
0
YPSILON CREEK
O
i i i r
0 O OoQO°
r iii
2500
50—1
3000
ELEVATION (m)
3509
CT
OJ
LOCH VALE
o 6> oo
O
I I II
I IT
2750
I I I
3000 3250 3500
ELEVATION (m)
50 —
cr
OJ
O
o
UPPER COLORADO RIVER
3000
3206 3400
ELEVATION (m)
3600
EAST INLET
o o> oooCP
o
^T ' I ^ I
2600 2800 3000 3200
ELEVATION (m)
3400
Figure 5. Graphs of Cl vs. elevation for subbasins in RMNP.
33
-------
188-1
o
ROARING RIVER
0©n (9°° 0
iii i i r
2500 3000 3500
ELEVATION (m)
4000
100-1
cr
0)
•a-
o
UPPER FALL RIVER O
O
80 o
o
0
0
°
Till
I I I I I I
2500
100-1
o
00
3000 3500
ELEVATION (m)
GLACIER CREEK
4000
O
O
2500
3000 3500
ELEVATION (m)
4000
108-1
cr
Oi
O
oo
cr
ocP8
o
-1 | I pi | I |
2600 2800 3000 3200 3400
ELEVATION (m)
Figure 6. Graphs of SO/, vs. elevations for subbasins in RMNP.
34
-------
59-1
cr
0)
9
ROARING RIVER
o
0
0 CP
Q
OD
Fill | M.I J I Ml |M I I |M I I |
2599 2759 3999 3259 3599 3759
ELEVATION
59—1
cr
01
9
UPPER FALL RIVER
ft°
II I I rl I I I I I M I I II I I I m
2599 2759 3999 3259 3599 3759
ELEVATION (m)
59-1
cr
0)
ro
O
9
GLACIER CREEK
O
o
O OQ O
o
2600 2899 3909 3299 3400 3609
ELEVATION (m)
59-i
cr _
01
CO
o
9
59-
cr
OJ
a.
ro
O
9
YPSILON CREEK
O 8
O
o o
i i i i I i i i i I T i i r I i i i i 1
2599 2759 3999 3259 3599
ELEVATION (m)
59-i
CT
0)
9
LOCH VALE
o
o 8 °
T ] i 7—r-f ] ^T I
2699 2899 3999 3299 3499 3699
ELEVATION (m)
59-1
cr
QJ
UPPER COLORADO RIVER
O
n
O
oo
3999
3299
ELEVATION
3499
3699
EAST INLET
1
0 $J On
1 '
I
0
1
2699 2899 3999 3299 3409
ELEVATION (m)
Figure 7. Graphs of N03 vs. elevation for subbasins in RMNP.
35
-------
situated on scoured bedrock to lower elevation lakes surrounded by moraine
veneer with thin soil cover. In addition, watershed slope decreases with
decreasing elevation, further increasing the contact time between precipita-
tion and neutralizing materials. These parameters are all difficult to
measure. Turk and Adams (1983) have shown that elevation used as a surrogate
for these and other unmeasured watershed parameters (e.g., residence time,
length of flow path, effective soil and bedrock area), successfully predicts
alkalinity. Our analysis shows that alkalinity, Cg* (excess Cg), and silicate
are all inversely related to elevation in subbasins with homogeneous
mineralogy and low alkalinities (Glacier Gorge, Loch Vale, Ypsilon Creek,
Roaring River, and East Inlet) (Figures 8 through 10).
This relationship between elevation and streamwater chemistry is obscured
when the data from more than one subbasin are used in the analysis. This
probably results from the differences in the distribution of glacial till over
elevation between subbasins in the same watershed. The relationship between
elevation and streamwater chemistry is overwhelmed by the variability in
mineralogy and subsequent weathering rates in the Upper Fall River and Upper
Colorado River basins (Figure 8). Although elevation contributes to the
variability of stream chemical composition in areas with homogeneous bedrock,
variability in mineralogy and other interwatershed variables can overwhelm
altitudinal effects.
Relationships between bedrock geology, surficial materials, soils
and stream water chemistry. The chemical composition of natural waters is
primarily a function of the interactions between atmospheric deposition,
bedrock geology, and surficial deposits. Previous researchers have found that
an area's ability to neutralize acidic deposition is the result of mineral
weathering and soil ion-exchange reactions (Norton 1980; McFee et al. 1977;
Johnson and Cole 1980). Under pristine conditions, the chemical dissolution
of minerals by carbonic acid results in a loss of hydrogen ion (acidity) and
the production of alkalinity (acid-neutralizing capacity), base cations, and
silica. The rates of these reactions vary with the mineralogy of the bedrock.
Carbonaceous minerals, such as calcium carbonate, dissolve very rapidly,
providing "infinite" buffering capacity, while silicious rocks, such as
granite, dissolve very slowly, offering little buffering capacity. Surficial
materials also play an important role in buffering acidic deposition,
as soils neutralize acidic deposition through cation and anion exchange.
36
-------
100 —
cr
tu
Zl
j*:
<
0 0 ° 0 iee-
o° <5>°
o ^ -
cr
Ol
°o 5
ROARING RIVER 5
i I i i | i I i i | i i i i i i i i i
Mill V
o
° o o 0°
o 0 o
YPSILON CREEK O
I I i i 1 i I I 1 1 1 I I I 1 I i i i 1
2500 2750 3990 3250 3500 3750 3590 2750 3000 3259 3500
ELEVATION (m) ELEVATION (m)
see —
-
cr
QJ -
n
-^ _
<
100 —
UPPER FALL RIVER
0 0
0 ^50~
8 oo o a 0 i :
0 0 0 5 .
1 1 1 1 1 1 M 1 1 1 M 1 1 1 1 1 1
Mill V
LOCH VALE
0 0
° 0 o °
1 1 ' 1 ' 1 ' 1 ' 1
2500 2750 3000 3250 3500 3750 2606 2890 3000 3200 3400 3600
ELEVATION (m)
199-
cr
o
1 1 ' 1 ' 1 ' 1
2600 2800 3000 3200 3400
ELEVATION (m)
Figure 8. Graphs of alkalinity vs. elevation for subbasins in RMNP.
37
-------
see —
ROARING RIVER
£ - 0 0
i o°o° °°
0 1 1 1 1 1 1 1 I
2500 3000
ELEVATION
500 -
200 —
0 -
0
1 1 1 1 1 0
3500 4000 25
(m)
YPSILON CREEK
° 0 °
00 o §o8
O
1 1 1 1 1 1 1 1 1 1
90 3000 3500
ELEVATION (m)
200—1
UPPER FALL RIVER ~
,-,
CT
OJ
* CQ f\ f~\
oo o
- o °
1 1 1 1 1 1 1 1
0 _
0 > ia0-
n -4
R° ~~" -
0 0
e_
LOCH VALE
0
o o o
o o o (§>
i i i i 1 i i i i | i i i i 1
2500 3000 3500 4000
ELEVATION (m)
2750 3000 3250
ELEVATION (m)
3500
100 —
0
GLACIER CREEK
0
o
O
Po
0
o
o
1I1IIII I III 1^1
2500 3000 3500 4000
ELEVATION (m)
500 —i
O
UPPER COLORADO RIVER
O 00
$ o
08 c
o
o
200 400
ELEVATION (m)
600
150-
50
I
:
—
_
EAST INLET
O
°o cb
o o
1 1 1 1 1
o
1
2600 2800 3000 3200 3400
ELEVATION (m)
Figure 9. Graphs of excess base cations vs. elevation for
subbasins in RMNP.
38
-------
•=1-
o
p
00
-
-
o
0 0
a
0
o iee
-
0 o ^ ° H
ROARING RIVER
I 1 1
1 1 1
1 1 M
1 1
<
3
MM
^£_
p.
O
CO _
ft
0
o
o o o o
0
o BO
YPSILON CREEK °
MI MM i i i i i i i n
2500 2750 3000 3250 3500 3750 2500 2750 3000 3250 3500
ELEVATION (m)
E00 —
100 ~
_
0..
25
0
ELEVATION (m)
100 —
So ^ ^ p
o
UPPER FALL RIVER
Mil
30 27
n i
50 30
MM
)0 32
&
(y>
V
ill '
;0 35
ft
\J
s
;±
*J-
o
oo ~"
A
1 1 1 1 | «
90 3750 26
ELEVATION (m)
ee —
,
40-
Oft
CO
GLACIER
O
i
0 0
i
CREEK
O o
1
8
i
O
i i
o
LOCH VALE u
o ^
o o o °
00 Q
1 1 ' 1 ' 1 ' 1
00 2800 3000 3200 3400 3600
ELEVATION (m)
500-
-
\ -
2:
^.
oo
0
UPPER COLORADO RIVER
o
°° n
o ° o
i 1 i 1 HP i
2600 2800 3008 3200 3400 3608 3000 3200 3400 3600
ELEVATION (m)
280-1
1 1
•=1-
o
-
_
nA
ELEVATION (m)
EAST INLET
O
o
0 o° o cP°o o
1 1
1 1 1 ' 1
2600 2800 3000 3200 3400
ELEVATION (m)
Figure 10. Graphs of silicate vs. elevation for subbasins in RMNP.
39
-------
Surface water chemistry, particularly alkalinity is an integration of these
mechanisms. As a result, alkalinity is frequently used as an index of sensi-
tivity.
The geology in the Park ranges from Precambrian granite to tertiary
intrusive and extrusive rocks. The difference in the weathering rates of the
minerals in these formations is reflected by the streamwater chemistry. The
highest concentrations of Cg*, alkalinity, and silicate occur in the Upper
Colorado River Basin, an area underlain by highly weatherable ash flow tuff
and andesite. The CD* and alkalinity concentrations in Glacier Creek, a
D
watershed underlain by Silver Plume granite, are an order of magnitude lower
than those in the Upper Colorado River Basin (Tables 9 through 10).
R-mode factor analysis was used to investigate the relationships among
the water chemistry variables and the bedrock and soil parameters. This
method of analysis has been used by several authors (Dawdy and Feth 1967;
Miller and Drever 1977a; Reeder et al. 1972) to interpret natural water chem-
istry in terms of its geochemical origin. In these analyses, factor analysis
is used to reveal the geochemical processes responsible for the stream chemis-
try composition. A brief review of factor analysis follows.
Factor analysis is a statistical data reduction technique that rearranges
the information contained in the correlation matrix for a set of variables
into a smaller set of independent factors. These factors are linear combina-
tions of the original variables. The first step in the analysis calculates
the principal components, or factors that explain the greatest amount of the
variances and co-variances in the correlation matrix. In the varimax solution
used in this analysis, these principal components are rotated orthogonally to
achieve a simple structure. This rotation produces a set of uncorrelated
factors, so that the factor loadings (the extent to which each factor is
associated with a particular variable) tend towards unity or zero. The re-
sulting factors are interpreted as source variables accounting for the rela-
tionships between the original variables.
The data set from RMNP was split into two geologic groups for this
analysis. One group represents all samples from areas underlain by granite
and gneiss; the other represents the samples collected from watersheds con-
taining tertiary volcanics. Each group was analyzed with and without a bed-
rock geology and soil parameter. The analysis of the stream chemistry alone
40
-------
allowed a larger sample size. Variables that had many zero values (K* and
NH3) were not included in the analysis. All factors with eigen values
greater than 0.51 are reported.
The results of the factor analysis of the granite and gneiss group show
that four factors account for nearly 93% of the variance in stream water
chemistry data (Table 11). The first factor, accounting for almost 50% of the
Table 11. R-mode varimax factor matrix of chemical data
for 88 lake and stream samples underlain by granite and
biotite gneiss and schist in Rocky Mountain National Park.
Variable
+1
Na
+2
Mg
+2
Ca
ci"1
_i
NO,
_2
S04
_4
Si04
Alk
1
0.934
0.827
0.325
-0.031
-0.150
0.259
0.937
0.538
2
0.243
0.346
0.919
0.082
-0.025
0.437
0.156
0.656
Factor
3
-0.185
0.092
0.144
0.112
0.945
0.609
-0.029
-0.409
4
-0.042
-0.127
0.068
0.975
0.078
0.479
0.180
0.277
% of variance
explained by factor 49.5
Cumulative % of
variance 49.5
23.6
73.1
12.0
85.1
7.7
92.8
variance, has high loadings for Na
SiCL, and alkalinity.
This factor
These two
+1
is interpreted as an oligoclase and biotite weathering factor.
minerals weather to kaolinite and vermicullite, respectively, releasing Na
Mg+2, Si04, HCO~} and a small amount of Ca+2.
41
-------
NaQ 7CaQ 3A1X 3Si2 ?0g + 3.45 H20 + 1.3 H2C03 = 0.65 A12S120
(oligoclase) (kaolinite)
+1.4 H4Si04 +0.7 Na+1 +0.3 Ca+2 +1.3 HCO'1
3 K2(Mg3Fe3)Al2Si6020(OH)4 + 24 H20 + 18 H2C03 -
(biotite)
2(Mg3Fe3)Al3Si5020(OH)4-8 H20 + 6 K+1 + 3 Mg+2 + 3 Fe+2 + 8 H4Si04 + 18 HCO"1.
(vermicullite)
The high percentage of the variance explained by this oligoclase and
biotite weathering factor suggests that primary mineral weathering is one of
the processes dominating stream water chemistry.
The second factor, accounting for 23.6% of the variance, is less easily
+2 -1 "2 +2
interpreted. This factor loads heavily on Ca , HC03, and SCL. Ca is not a
major bedrock element, although a small percentage is contained in the
+2
oligoclase. Ca in precipitation, however, is quite high and is also con-
tributed to by dry deposition of dust and salts. This factor can be inter-
preted as a dry deposition factor, caused by the deposition of CaS04, and
possibly CaCO...
The third factor, accounting for 12% of the variance, is an acid deposi-
-1 -9
tion factor The high loadings of NCL , SCL , with an inverse relationship
between the acid anions and alkalinity, represents the titration of lake and
stream HC03 by anthropogenic acids. The fact that NCL loads higher on this
factor suggests that HN03 may be a more important component of acid precipita-
tion than H2$04. The fourth factor, explaining 7.7% of the variance repre-
sents atmospheric deposition but does not appear to involve any buffering
mechanisms.
The addition of percent unreactive rock (quartz + microcline) and percent
soil organic matter (% O.M.) to the factor analysis results in a decrease in
sample size and the loss of the acid deposition factor (Table 12). The first
+?
factor still represents oligoclase and biotite weathering, although Ca loads
42
-------
Table 12. R-mode varimax factor matrix of stream chemistry, % soil
organic matter, and % unreactive rock for 40 lake and stream samples
underlain by granite and biotite gneiss and schist in Rocky Mountain
National Park.
Variable
Na+1
+2
Mg 2
Ca+2
ci"1
NO^
12
S04
_4
Si04
Alk
% O.M.
% rock
1
0.958
0.917
0.558
0.009
-0.226
0.275
0.917
0.741
0.101
-0.118
2
-0.064
0.208
0.727
0.273
0.851
0.701
0.053
-0.066
-0.107
0.085
Factor
3
0.111
0.084
0.354
0.212
-0.212
-0.172
0.024
0.591
0.064
-0.953
4
-0.066
-0.090
-0.042
0.923
0.286
0.543
0.238
0.140
-0.087
-0.112
5
0.164
-0.154
-0.048
-0.082
-0.093
-0.116
0.168
0.049
0.978
-0.062
% of variance
explained by factor
Cumulative % of
variance
41.7
41.7
25.1
66.8
12.4
79.2
9.0
88.2
6.1
94.3
somewhat higher than in the previous analysis. The second factor still repre-
sents atmospheric deposition of CaSO, in dust and salts, although N03 also
loads heavily on this axis. The third factor represents the inverse relation-
ship between HCCL and unreactive rock, further evidence that primary mineral
weathering plays a dominant role in stream chemistry. The fourth factor
represents atmospheric deposition. The fifth factor represents % O.M., which
is unrelated to any other variable, suggesting that soil ion-exchange
processes play a very minor role in stream chemistry. The factor analysis of
stream samples from areas underlain by tertiary volcanics shows that four
factors account for 86.4% of the variance (Table 13).
The first factor, accounting for over 40% of the variance, indicates that
the weathering processes in these watersheds are very different from those in
43
-------
Table 13. R-mode varimax factor matrix of stream chemistry
for 33 lake and stream samples underlain by tertiary
intrusive bedrock in Rocky Mountain National Park.
Variable
Na+1
Mg+2
Ca+2
i
Cl
i
NO,
_2
S04
_4
Si04
Alk
Factor
1
0.122
0.835
0.772
0.277
-0.036
0.853
0.006
0.881
2
0.911
0.152
-0.410
0.033
-0.219
0.121
0.884
0.127
3
-0.225
-0.264
0.138
-0.025
0.946
0.185
-0.066
-0.184
4
-0.076
0.129
0.115
0.955
-0.025
0.095
0.121
0.247
% of variance
explained by factor 40.3
Cumulative % of
variance 40.3
26.5
66.8
10.0
76.8
9.6
86.4
_i -9 +2 +2
the granite and gneiss areas. HCO- , SO. , Ca , and Mg all load heavily on
this factor, representing the weathering of mafic minerals low in silica, as
well as the dissolution of CaSO. in the Pierre shale of the Upper Colorado
Basin. The second factor explains 26.5% of the variance and loads heavily on
+1 ~4
Na and SiO» . This factor can be described as oligoclase weathering. The
third and fourth factors, accounting for 19.6% of the variance, each explain a
single variable and cannot be interpreted in terms of buffering mechanisms.
The addition of soil and bedrock parameters in this analysis reduced the
sample size to 16 observations, too few to be used with factor analysis.
The results of the analyses of the two geologic groups suggest that
primary mineral weathering is the major mechanism underlying the stream
chemistry. The weathering of oligoclase and biotite, the dry deposition of
CaSO^ dust, and the titration of bicarbonate by anthropogenic acids appear to
be the major geochemical processes in the watersheds underlain by granite and
biotite gneiss and schist. An assemblage of low-silica, high-sulfate minerals
44
-------
appears to be responsible for much of the stream chemistry in areas underlain
by tertiary intrusives. Oligoclase weathering plays an important role in the
chemistry of these watersheds, while no evidence of acid titration of bicarbo-
nate was found.
Discriminant function analysis (DFA) was used to examine the differences
in stream chemistry between the areas underlain by tertiary volcanic bedrock
and those surrounded by granite and biotite gneiss and schist. DFA dis-
tinguishes between two populations on the basis of observations of multiple
variables. DFA may also be used to classify data on the basis of observed
variables. In this two-group discriminant analysis, one discriminant function
is formulated by the analysis. This function is a linear combination of the
measured variables, i.e.,
L = BlXl + B2X2 + . . . + BnXn ,
where L is the discriminant function, X are the measured variables, and B
are the discriminant function coefficients. The discriminant function L is
formulated to achieve the maximum discrimination between the two groups; i.e.,
the variance in L within each group is much less than the variance in L
between the two groups. The discriminant function analysis also indicates
which variables differ most between the two groups. The correlation between
the measured variables and the discriminant function (ranges between -1.0 and
+1.0) gives an indication of the importance of that variable in differen-
tiating between the two groups.
In this application, DFA is used to differentiate between the two major
geologic groups (tertiary volcanics vs. granite and biotite gneiss and schist)
on the basis of the water chemistry parameters. The results of the DFA show
that the two groups are significantly different (Table 14). The correlations
between the water chemistry parameters and the discriminant function show that
+2 +2 ~2
alkalinity, Mg , Ca , and S04 are the parameters responsible for the
difference between the two geologic groups. These are the same variables that
make up the first factor in the factor analysis of the tertiary volcanic
group. This result is consistent with the belief that the differences in
stream chemistry between the two geologic groups are caused by mineral
weathering processes. The reclassification of the data set on the basis of
45
-------
Table 14 Discriminant analysis of surface
water chemistry from 117 lake and stream
samples from Rocky Mountain National Park.
Variable Correlation
Alkalinity 0.854
Mg+2 0.823
Ca+2 0.615
SO'2 0.558
CT1 0.348
SiO~4 0.337
Na+1 0.297
NO"1 -0.173
the discriminant function resulted in a 95.7% correct classification
(Table 15).
The results of this analysis show that water chemistry characteristics of
areas underlain by similar bedrock geology can be estimated on the basis of
Table 15. Reclassification results.
Predicted group membership
Actual group No. of cases
1 2
Group 1 (granite and gneiss) 88 88 0
100.0 0
Group 2 (tertiary intrusives) 29 5 24
17.2 82.8
Percent of grouped cases correctly classified = 95.73
46
-------
geologic type. Areas with tertiary intrusive rocks present in their catch-
ments can be expected to have significantly higher alkalinity, magnesium,
calcium, and sulfate than areas underlain by granite and gneiss.
Summary. The chemical composition of the waters in RMNP is a product of
the interactions between atmospheric deposition and bedrock geology and
surficial materials. Soils play a minor role. The previous discussions show
that bedrock mineralogy, atmospheric deposition, and elevation all signifi-
cantly affect the stream chemistry in RMNP.
Primary mineral weathering appears to be the dominant mechanism deter-
mining the concentrations of base cations, silica, and alkalinity throughout
the park. Factor analysis shows that the primary mineral weathering of
oligoclase and biotite account for almost 50% of the variance in stream
chemistry in areas underlain by granite and biotite gneiss and schist. In
areas that contain tertiary volcanic bedrock, the mineral weathering of mafic
minerals, sulfur-bearing minerals, and oligoclase account for more than 50% of
the variance in stream chemistry. Soils appear to have little effect on
stream chemistry. The soils are highly permeable, low in clays, and very
thin. Soil organic matter accounts for most of the soil CEC, but % O.M. does
not form a factor with any of the stream chemistry variables.
Alkalinity, CS, and sulfate are inversely related to elevation in the
Glacier Creek, Loch Vale, Ypsilon Creek, Roaring River, and East Inlet sub-
basins. This is a result of the deeper glacial till (larger flow path) and
gentle gradients (larger residence time) at lower elevations.
Atmospheric deposition is the primary source of chloride and nitrate in
the streams of RMNP. Atmospheric deposition is also the primary source of
sulfate in RMNP waters, with the exception of the Upper Colorado and Upper
Fall River basins, where the weathering of sulfur-bearing minerals is a source
of sulfate. Chloride and sulfate are relatively constant with elevation,
while nitrate concentrations are highest above the timberline, where biolog-
ical activity is lowest. Atmospheric deposition is also a significant source
of stream water Cn, a result of the deposition of airborne dust and salts from
the dry, windy regions upwind of RMNP.
Discriminant function analysis of the water chemistry data shows that
bedrock mineralogy can be used to estimate the water chemistry of RMNP
Bedrock mineralogy will be used in later sections to assess the sensitivity
47
-------
(as measured by alkalinity) of similar geologic areas in the central Rocky
Mountain region.
Alkalinity (Sensitivity) of RMNP Lakes and Streams
An area's ability to neutralize acidic deposition through interactions
with bedrock and surficial geology determines its vulnerability to acidic
deposition. The lithological characteristics of a watershed, combined with
its water chemistry data, provide the basis for assessing the area's sensi-
tivity to acid rain. Alkalinity, an integrator of watershed buffering mecha-
nisms, is often used as an index of sensitivity. Hendrey et al. (1980) define
sensitive waters as those with alkalinities lower than 200 ueq/1, a level low
enough to be neutralized by acidic deposition and runoff. Using this defini-
tion, we find that much of the RMNP is sensitive to acidic deposition.
As we have seen in the previous sections, the sensitivity of the water-
sheds in RMNP is primarily determined by the bedrock geology of the water-
sheds. Within each watershed, elevation may be used to further divide the
basins into areas of different sensitivities. The classification scheme used
for assessing the sensitivity of RMNP to acidic deposition defines sensitive
waters as those with alkalinities less than 200 ueq/1, while waters with
alkalinities less than 100 |jeq/l will be considered very sensitive. Lakes and
streams with alkalinities below 50 ueq/1 are classified as extremely sensi-
tive. Following this classification scheme, we have evaluated the sensitivity
above and below 3300 m in each subbasin (Figure 11). The results show the
following classifications:
Extremely sensitive Glacier Gorge
(alkalinity ^ 50 peq/1) Ypsilon Creek
Very Sensitive Roaring River
(50 ^ alkalinity ^ 100 ueq/1) Upper East Inlet
Sensitive Lower East Inlet
(100 ueq/1 alkalinity ^ 200 (jeq/1) High elevations of
Upper Fall River
Nonsensitive Lower elevations of
(alkalinity £ 200 ueq/1) Upper Fall River
Upper Colorado River
Current Acidification Status of RMNP
Researchers have observed acidic deposition in the Rocky Mountains since
1967 (Lewis and Grant 1979). These authors report a decrease in stream
48
-------
UPPER COLORADO RIVER
BASIN
D
Extremely Sensitive PTT1 Very Sensitive
(alkalinity < 50 neq/d) 111:-] (50 < alkalinity < 100)
l^ Sensitive
:•:•:•] (ioO < alkalinity < 200)
n
Non-sensitive
(alkalinity > 200 yeq/1)
Figure 11. Spatial distribution of sensitivity in RMNP
(see map Figure 1).
49
-------
bicarbonate in the Como Creek watershed of north-central Colorado over a
150-week period. This record, however, is too short to be considered evidence
of increasing acidification. Lewis (1982) reports an average decrease in
alkalinity from 22 mg/1 to 18 mg/1 as C02 [equivalent to a decrease from 1000
ueq/1 to 818.2 peq/l (Lowenthal and Marias 1978)] for 104 lower-elevation
lakes surveyed by Pennak from 1938-1942 and resurveyed by Lewis in 1979.
Although Lewis attributes this loss to acidic deposition, the concurrent
decrease in total residue suggests that hydrologic variability is responsible
for this decrease in alkalinity. The high discharge in 1979 (-30% above
average) and the similar decrease in total residue and alkalinity (22% for
alkalinity, 21% for total residue) suggests that this decrease is mainly
caused by dilution. In addition, a 180 p.eq/1 loss of alkalinity is much
greater than any alkalinity loss observed in acidified regions of the north-
eastern United States (Hendrey et al. 1980). Although several areas in the
Rocky Mountains have been shown to be potentially sensitive to acidic deposi-
tion (Harte et al., submitted; Dodson 1981; Turk and Adams 1983), no con-
vincing evidence of acidification has been presented.
At present, RMNP is receiving much less acidic deposition than acidified
regions in the northeastern United States. A comparison of the (volume-
weighted average) concentrations of the major ions in precipitation show that
the precipitation at RMNP contains much less acid than that at Hubbard Brook
(Table 16) (NADP 1982). During 1981 the average precipitation pH at RMNP was
5.07, compared with an average of 4.33 at Hubbard Brook. Sulfate concentra-
tions at Hubbard Brook are also higher than those observed at RMNP (48.9 peq/1
at Hubbard Brook, compared with 35.0 jjeq/1 at RMNP), while the CB concentra-
tion at RMNP is more than double the concentration at Hubbard Brook. However,
the nitrate concentrations observed at these two locations are very similar,
21.9 (jeq/1 at RMNP, compared with 21.2 peq/1 at Hubbard Brook. These results
suggest that much of the acidity observed in RMNP precipitation may be caused
by nitrate, while the sulfate is probably a combination of anthropogenic
emissions of sulfur dioxide, along with sulfate associated with CD from air-
D
borne dust and salts.
Since no historical water-chemistry data are available for RMNP, we base
our assessment of its present acidification status on the current composition
of its waters. According to electroneutrality conditions:
50
-------
Table 16. Comparison of Rocky Mountain National Park
and Hubbard Brook precipitation chemistry (National
Atmospheric Deposition Program 1982).
Ion
H+
SO'2
NO^1
cr1
Ca+2
Mg+2
K+1
Na+1
Vol. wt.
average
(Meq/1)
8.
35.
21.
4.
21.
8.
5.
3.
CB = H
6
0
9
9
9
1
8
0
RMNP
Yearly
deposition
(meq/m2)
3.
12.
7.
1.
7.
2.
1.
2.
L + S0~2 + N
0
2
5
7
7
9
1
1
'Og1 + CT1
Hubbard
Vol. wt.
average
(Meq/D
46.
48.
21.
5.
6.
3.
0.
5.
- H+1 - metals
5
9
2
3
5
6
4
1
+n
Brook
Yearly
deposition
(meq/m2)
71.1
75.8
32.5
8.3
10.4
5.6
0.7
7.9
Under acid rain conditions, anthropogenic acids (H^SO, and HMO,) reduce the
relative concentration of alkalinity in this equation by titration. We can
use the "excess" concentration of base cations to provide an estimate of the
alkalinity replaced by acid anions (i.e., amount of acidification). After
correcting for the deposition of salts and excluding H and metals, which are
negligible at the pH of water in RMNP, the ion balance equation is reduced to:
CB* - HCO'1 = CA* ; where CA* = NO'1 + S0~2* .
The results of these calculations for the most sensitive watersheds
(Glacier Creek, Loch Vale, East Inlet, and Ypsilon Creek) show that these
waters have, at the most, suffered a small loss of alkalinity (Table 17). It
51
-------
Table 17. Calculation of acidification status for Rocky Mountain
National Park watersheds according to ion balance considerations.
Watershed
Roaring River
Ypsilon Creek
Upper Fall River
Andrews Creek
Loch Vale
Glacier Creek
r*
B
(peq/1)
72.3
56.2
155.2
57.3
47.9
47.6
A 1 ka 1 i n i ty
(ueq/1)
74.4
48.0
180.5
38.8
41.2
40.3
Calculated
= Acidification
(ueq/D
None
8.2
None
18.5
6.7
7.3
Upper Colorado River
East Inlet
280.1
91.5
319.0
85.5
None
6.0
is so small that the combined effect of analytical error and the error
associated with the correction for atmospheric salts is probably as large as
the calculated acidification. The Upper Colorado River, Upper Fall River, and
Roaring River show no evidence of acidification.
A similar method for evaluating the current acidification status of low
ionic strength lakes is the "predictor nomograph" developed by Henriksen
(1980). This model was empirically derived to evaluate the impact of in-
creased acid precipitation on lakes in Norway but may also be used to assess
current acidification status. The model is based on electroneutrality condi-
tions, assumes no increase in weathering of base cations, and considers
_ p
atmospheric deposition to be the only source of SCL . The nomograph is a plot
of the "excess" Ca+ and Mg+2 vs. "excess" SO" in lake waters. "Excess"
-?
means nonmarine in origin. The lake SCL concentrations have been correlated
-2
with pH and SO^ concentrations in rain by a regression analysis of data from
52
-------
719 Norwegian lakes. The graph has been divided into three sections to
represent three stages of acidification. The first stage represents waters
that still contain enough alkalinity to buffer incoming acid precipitation,
"bicarbonate lakes." The second stage of the nomograph is representative of
"transition lakes." These waters experience rapid fluctuations in pH because
of their low alkalinities. The third stage of acidification are the "acid
lakes", characterized by low pH and increased aluminum concentrations. The
nomograph is used to predict acidification status by plotting precipitation pH
or excess lake SO^ * with "excess" Ca + Mg in ueq/1. This simple
empirical model has been successfully applied to lakes in the Adirondack,
Canada, Scandinavia, and Scotland (Wright et al. 1980). Although there are
some differences between these areas and RMNP (notably the soils), the simi-
larity of geochemical processes should allow our use of the nomograph with
some changes.
We have modified the Henriksen nomograph to use as a tool to evaluate the
+2 +2
current and future effects of acid rain in the Rocky Mountains. Ca and Mg
+1 +2
are the major base cations in Henriksen1 s study area, while Na + Mg are
the dominant cations in RMNP. As a result, we have replaced the "excess"
+2 +2
Ca + Mg used by Henriksen as the y_ axis in the nomograph with CB*. As
previously stated, RMNP receives minimal sea-salt deposition but does receive
atmospheric deposition of salts and dust. Cn* is our best estimate of
"excess" base cations.
Since much of the acid deposition in this region is in the form of HNO,
(NADP 1982; Lewis and Grant 1979; Kelley and Stedman 1980), we have further
_2 -i
modi fed the Henriksen nomograph by using C,* (SO .* + NO^ *) as the x axis in
the nomograph. The waters in RMNP contain a large indeterminate "natural," or
_2
background, concentration of SO. , a result of the atmospheric deposition of
-2
dust and salts. We expect that only part of the S04 in RMNP lakes is the
result of acid deposition. Aimer et al. (1978) estimate the background
_2
concentration of SO. in Scandinavian lakes to be 20-60 ueq/1. To estimate
-2
acidic deposition, we will use Aimer's lowest estimate of background SO* to
-2
calculate a maximum "excess" SO. *:
S0~2* = S0~2 - 20.0 ueq/1 .
In this scenario, CA* = NO"1* + S0~2*.
53
-------
Plotting this information on the nomograph shows that most of the lakes
in RMNP can be classified as "bicarbonate", while a few approach the
"transition" stage (Figure 12).
see —
BICARBONATE
TRANSITION
ACID
'I I I I I I I I I I I I I I I I I
0 59 100 150 200
C^ (yeq/1)
Figure 12. Status of 23 lakes in RMNP.
The high cation concentrations in RMNP precipitation indicate that the
park is undoubtedly receiving "natural" deposition of sulfate in the form of
salts and dust from the surrounding arid regions. However, the low pH of
Rocky Mountain precipitation indicates that some of the sulfate and nitrate is
being deposited as acid deposition. It is likely that the waters in RMNP have
suffered some loss of alkalinity because of acidic deposition, but this loss
(a maximum of -10 ueq/1) is minor compared with that experienced in lakes in
the northeastern United States.
Future Impacts of Acidic Deposition
As we have seen in the previous sections, the Central Rocky Mountains are
extremely sensitive to acidic deposition but have as yet suffered little or no
acidification on a regional basis. An increase in acidic deposition could
have some serious consequences. The development of major coal and oil shale
resources upwind of this region and the subsequent increase in acidic deposi-
tion could have a serious impact on the surface water acidity in the region.
Using the Henriksen predictor nomograph described in the previous section, we
can estimate the best- and worst-case consequences of an increase in the
54
-------
current rate of deposition, to that experienced in the northeastern United
States. The scenario for increased acidic deposition in RMNP assumes a
decrease in precipitation pH to that experienced in the northeastern United
States. This involves an increase in H , from pH 5.1 to 4.3, which will be
accompanied by an increase in lake Cft* of approximately 80 ueq/1.
In the worst-case scenario, the increase in acidic precipitation will not
increase CR* but will only result in decreased alkalinity. Using our estimate
_2 -i
of current Cft*, (S04 * + N03 * 20 ueq/1) a worst-case prediction using the
nomograph indicates that most of the lakes in RMNP will reach "acid" status,
while the remainder will be classified as "transition" lakes (Figure 13).
In the best-case scenario, the increase in acidic deposition will be
accompanied by an increase in C * of 0.4 ueq/1 per 1.0 ueq/1 C * This
D H
increase in Cp* with increased acidic deposition was empirically calculated by
Henriksen using data from low-alkalinity lakes in several areas. The best-
case scenario predicts that a few lakes will remain "bicarbonate," the
majority will become "transition" lakes, and several lakes will still reach
"acid" status (Figure 13).
Henriksen's evaluation of data sets from Norway, Sweden, Canada, and the
United States shows that there is an increase in base cation weathering with
acid rain for some, but not all watersheds. Increases in Cg will probably
occur in regions that have soils with high levels of exchangeable bases. When
these areas receive acidic deposition, base cations on the soil exchange sites
will be replaced with H by mass action, increasing surface water Cg*. In
regions with poorly buffered soils, the increase in Cg* with acid deposition
will be smaller, since fewer exchange sites contain base cations for ion
exchange. Other researchers have shown that the rate of primary mineral
weathering in areas with granitic and metamorphic rock does not increase under
acid rain conditons (Johnson et al. 1981). The low ion-exchange capacity of
the soils in RMNP and the bedrock composition indicate that the increase in
CR* with increased acidic deposition in RMNP will be low and that with in-
creasing acidic deposition many of the lakes will shift from bicarbonate
towards acid status.
55
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BEST
CASE
200 —I
190 —
BICARBONATE
TRANSITION
ACID
I I I I | I I I I | I I I I | I I i i | CA (yeq/i;
50 100 150 300
n i i r
4.9 4.55 4.33 4.2
PH
WORST
CASE
298 —i
190 —
BICARBONATE
TRANSITION
ACID
i i i i r i i | i ri i | i i r i
l 50 100 150 200
"1 I I 1
4.9 4.55 4.33 4.2
PH
Figure 13. Predictor nomographs projecting the best and worst-case
estimates of the effects of increased acidic deposition on lakes in RMNP
56
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YELLOWSTONE NATIONAL PARK
INTRODUCTION
Located in northwestern Wyoming at the northern edge of the potentially
sensitive Rocky Mountain region, Yellowstone National Park (YNP) is charac-
terized by extreme variability in geology, geologic history, and water chem-
istry. The 3,742 square mile park contains four large lakes (Yellowstone,
Shoshone, Lewis, Heart), and numerous streams, rivers, and small back-country
lakes, a number of which support trout populations. As in the case of Rocky
Mountain National Park, the general objectives of the study in Yellowstone
National Park were to determine the sensitivity of waters to acidification by
current levels of acid precipitation and to determine whether this will affect
fish populations. The accomplishment of these objectives is based primarily
on the evaluation of a water chemistry data base developed over the last 30
years.
DESCRIPTION OF GEOLOGY
Topographically, Yellowstone is dominated by a high plateau from about
1800 to 2800 m in altitude. The plateau is bounded on three sides by
mountain ranges: the Gal latin and Beartooth mountains to the north, the
Absaroka range to the east, and uplands from the Teton and Washakie ranges in
the south (Cox 1973). The continental divide transects the park along the
southwestern edge—approximately 20 percent of the park area drains west into
the Snake River basin, and 80 percent drains east into the Missouri River
drainage.
Cox (1973) divided Yellowstone into seven hydro!ogic units following
geologic and geographic boundaries. These are: Rhyolite plateau (RP),
Gal latin (GT), Beartooth (BT), Absaroka (AB), Falls River (FR), Snake River
(SR), and West Yellowstone (WY) (Figure 14). The plateau area (RP) is under-
lain by Tertiary and Quaternary rhyolite flows, while north and south of the
57
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Figure 14. Regional-geological map of Yellowstone National Park (adapted
from Cox 1973). (AB) Absaroka region is predominantly andesitic lava
flows and breccia, with basalt, and some occurrence of rhyolite, sandstone,
and limestone; (BT) Beartooth region is a mix of Precambrian granites,
Paleozoic and Mesozoic sandstones and shales, and Tertiary/Quaternary
volcanics; (FR) Falls River region is Quaternary rhyolite and basalt,
frequently overlain by alluvial and glacial deposits; (GT) Gallatin
region is Precambrian granites, Paleozoic and Mesozoic limestones,
sandstones, and shales, Tertiary/Quaternary volcanics; (RP) Rhyolite
plateau region is predominantly Tertiary and Quaternary rhyolite flows;
(SR) Snake River region is Paleozoic and Mesozoic limestones, sandstones,
and shales, with some outcroppings of Tertiary rhyolite and andesite; (WY)
West Yellowstone region is rhyolite overlain by alluvial, glacial, and
lacustrine deposits.
plateau are a heterogeneous, heavily faulted mix of PreCambrian granites,
Paleozoic and Mesozoic limestones, shales, and sandstones, and more recent
(Tertiary, Quaternary) volcanic deposits (GT, BT, SR). Between the plateau
region and the Gallatin range along the extreme western park border lies a
series of deep (c.200 feet) alluvial and glacial deposits underlain by
volcanic rocks (WY). East of the plateau is a mountainous area composed
58
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mostly of Tertiary andesitic lava flows and breccia (AB), while basalt flows
occur in the extreme southwest (FR).
Rhyolite, located in the southwest and central portion of the park as
well as in outcroppings throughout the rest of the region, is clearly the
dominant bedrock type. Extremely rich in silica, rhyolite is chemically
nearly equivalent to granite (Bryan 1979). Although fairly uncommon through
the world, nearly all geysers are associated with rhyolite formations, since
the rock provides the pressure-tight "piping" necessary for geyser creation.
The rhyolite in Yellowstone consists primarily of lava and welded tuff with
assorted deposits of breccia, ash, and glass. All of the types are chemically
similar, although tuff may be slightly more weatherable than lava due to
differing extrusion and deposition processes (Herzog 1982; Cox 1973).
Rhyolite may be altered by hot water and gas near hot springs.
Weatherability of the bedrock types may be roughly ranked by chemical
characteristics as follows (Herzog 1982 and personal communication; Loughnan
1969):
low granite, rhyolite
ash flow tuff
metamorphics—biotite gneisses and schists
andesite
basalt
high limestones, shales, sandstones
In addition to a heterogeneous geology, the park bears the ubiquitous remains
of three major glaciations originating in the Absaroka Range and Beartooth
Mountains. Most of the current park deposits date to the last major glacia-
tion, the Pinedale (10-30,000 years b.p.), which covered 90% of the park.
Abundant till and kame deposits throughout Yellowstone attest to the influence
of these geologic events.
DETERMINATION OF SURFACE WATER CHEMISTRY
Surface water quality studies in Yellowstone date to as early as the 19th
century, when Gooch and Whitfield (1888) published the first chemical data for
Yellowstone Lake. Until comparatively recently, however, surveys concentrated
59
-------
on the four largest lakes, all of which are chemically insensitive to acidi-
fication by acid precipitation (alkalinity >200 ueq/1). Chemical surveys of
the more vulnerable back country lakes were initiated in 1964 by the
Yellowstone National Park Fishery Management Investigation, and continue to
the present.
Field pH and alkalinity were measured with a Hach Field engineers kit
until 1974, when the Hellige kit was introduced for pH measurements. During
1969 and 1970, laboratory analysis of water samples were performed by the
Bureau of Indian Affairs Soil Laboratory in Gallup, New Mexico. (No labora-
tory analyses were performed from 1971 to 1973. ) Beginning in 1974 and con-
tinuing to the present, lab analysis of samples was performed by Orlando
Laboratories, Orlando, Florida. Almost all samples were refrigerated, mailed
within two days, and processed within a week. Analytical methods used by both
labs were in accordance with then-current Standard Methods for the Analysis of
Water and Wastewater.
All pH values reported in this study were obtained colorimetrically in
the field. Burns et al. (1981) found that measurements from a Hellige kit
agreed to within 0.15 pH unit with potentiometric values, although Pfeiffer
and Festa (1980) report a systematic bias expressed by the following
relationship:
Old (Hellige) = 0.6639 (pH meter) + 2.534
r2 = 0.91
All alkalinities reported were determined in the laboratory by colori-
metric titration to pH 4.6 (Standard Methods #403), except during the years
1965-1966 and 1971-1973, when only field measurements were taken. Field
alkalinities were determined colorimetrically during this period with the Hach
field engineers kit (Model DR-EL or AL-36-P). Colorimetric titrations do
overestimate alkalinity by the amount of free hydrogen ion in solution at the
endpoint; at titration to pH 4.6, this is 25 peq/l alkalinity for all samples.
Analytical methods for major cations and anions are given in Table 18 for the
years 1969-1970 and 1974-present. The current (15th edition) Standard Methods
is referenced in Table 18, although it is assumed that the most recently
available version was followed for historical samples. Quality assurance was
determined by calculating ion balances for all those lakes with complete
60
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Table 18. Analytical methods, Yellowstone National Park.
Parameter
Method, 1969-70
Method 1974-present
Alkalinity
Calcium
Magnesium
Sodium
Potassium
Sulfate
Chloride
Standard method #403. Colorimetric titration using
phenolphthalein (end point pH 8.3) and methyl orange (end
point pH 4.6) indicators
Standard method #306C
EDTA titrimetric
Hach Method, p. 122
Titrimetric
Standard method #313C; calculation from EDTA hardness
Standard method #325B; flame photometric
Standard method #3228; flame photometric
Standard method #427A
Gravimetric with ignition
residue
Standard method #407A; argentometric
EPA #375.4
Turbidimetric
(Standard methods 1980; EPA 1979; Hach 1978)
chemical records (see Appendix D). Lakes with ion balances with absolute
values less than or equal to 20% are considered usable for the purposes of
this study.
The 106 lakes discussed in this report represent a significant sample of
all the lakes in YNP. All the major lakes have been surveyed, including those
of special recreational or scientific significance. Every region, major
geological formation and geochemical type of lake has been sampled in the
survey. Because of its large size, Yellowstone Lake was surveyed at four
different locations in the lake. The chemistry of the lakes not surveyed may
be inferred by the chemistry of neighboring surveyed lakes.
RESULTS AND DISCUSSION
As stated in the introduction, the RMAS project relied on available data
from Yellowstone National Park. There was thus no opportunity to design a
sampling program to test hypotheses relating lake and stream sensitivity to
elevation, soils, and geology, as was the case for Rocky Mountain National
61
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Park. YNP data were available for lakes only, and there had been no attempt
to obtain data on complete watersheds or to relate sampling locations to
elevation, soils, or geology. In addition, water chemistry data were obtained
over the years using different analysis methods and samples were analyzed by
different laboratories. All of these factors made it impossible to carry out
the extensive evaluations reported in the chapter for Rocky Mountain National
Park. The evaluation of information from YNP focuses on sensitivity or
alkalinity, which are the critical factors in assessing the health of fish
populations. In addition, the general YNP findings can be compared with those
from RMNP to verify the ability to extrapolate results from one region to
another.
Lake Alkalinities (Sensitivities)
A spatial sensitivity, map, using alkalinity as an index of vulnerability
to acidification, was created for the park with recent alkalinity data
(Figure 15). The selection of alkalinity as the best index of sensitivity to
acid precipitation is based on its physical significance as the emergent sum
of many acid-neutralizing processes occurring in the watershed, and its well-
documented relation to pH (Henriksen 1979). Using Hendrey et al.'s (1980)
convention, those lakes with alkalinity values <200 |jeq/l are considered
potentially sensitive to long-term inputs of acid precipitation. For
Yellowstone, lakes with alkalinity values reported as 230 or less are con-
sidered in this category, due both to the underestimation implicit in colori-
metric titrations, and to account for imprecision in the analysis. One fourth
(30 of 106) the surveyed lakes may be considered "sensitive" by this crite-
rion. Thirteen of these lakes show alkalinities ^100 (jeq/1, although at least
six are influenced by thermal springs or humic acids (YNP Fishery Management
Investigations reports).
Excluding those lakes that are located in the midst of major geothermal
areas, the lowest alkalinity measured was 40 ueq/1. Yellowstone lakes on the
average apparently show considerably greater levels of alkalinity than those
determined for Rocky Mountain National Park lakes, probably due primarily to
differing geology between the two areas (most of the Rocky Mountain National
Park samples are collected in areas underlain by Precambrian granites and
metamorphic rocks). Of the four basins considered in the RMNP study, the
Upper Colorado River watershed is geologically the most similar to Yellowstone,
62
-------
oV.
ooq>*
}o°
0
o
o q-
0
•> ^,
o
o
©00
©
o
o
So
9)
©
w
• o
0 0
tf
O 3
© n
*»°
O
^
0
ALKALINITY,
• ^ 100
3 101 -200
O 201-500
O ^500
YELLOWSTONE NATIONAL PARK LAKES
Figure 15. Alkalinity map, Yellowstone National Park.
Yellowstone, as it shows a significant ( ca. 8%) accumulation of volcanic
rocks. This watershed shows the highest alkalinity and pH values of the RMNP
study sites [average alkalinity equals 248 (jeq/1 (this study)].
Although the low-alkalinity (<230-|jeq/l) lakes in Yellowstone show no
clear geographical (spatial) patterns, a geological pattern is evident. Most
occur within the large rhyolite flow which rises from the southwest and
63
-------
spreads along the central-west and central portions of the park. Lakes with
slightly higher alkalinity values (ca. 300 peg/I) are found in the extreme
southwestern Fall River basalt formation and the northwestern part of the
rhyolite plateau. Most of the northernmost lakes, dominated by andesites and
basalts, show very high alkalinity (>1000 ueq/1) and are not sensitive to acid
deposition. The exception to this is a group of five high-altitude lakes of
the Specimen Creek drainage in the northwestern corner of the park. These
small headwater lakes have an andesite-basalt bedrock but show very low
alkalinities (<200 ueq/1). The water supply of these lakes is primarily from
snowmelt (YNP 1965-1981)) and lakewater chemistry appears to be influenced
more by this dilute source than by reaction with the surrounding bedrock.
Field pH measurements were used to create a spatial pH map to complement
alkalinity in determining geographical distributions of sensitivity
(Figure 16). The pH map for Yellowstone shows most lakes with circumneutral
pH's of 6.5-7.49, and most of the rest of the lakes slightly to strongly
alkaline. Six of the 106 lakes have pH values less than 6.5. Of these six,
two are unquestionably influenced by thermals and one probably so, and three
are dystrophic lakes. As with the high alkalinity lakes, the greatest pro-
portion of high pH lakes is found in the northern part of the park.
A similar map denoting sulfate concentrations for the Yellowstone lakes
(Figure 17), shows a cluster of high sulfate lakes in the north and central
east areas; these lakes are generally characterized by high alkalinity (>1600
ueq/1) and in some cases are found in low-lying marshy areas. Sulfate in
these lakes probably has a biological and/or bedrock component (YNP
1965-1981). Sulfate concentration in lakes throughout the rest of the park
shows no particular trends; most lakes show sulfate values <200 ueq/1, while a
majority of lakes in the rhyolite bedrock have sulfate concentrations <100
ueq/1.
The alkalinity, pH, and sulfate maps for Yellowstone must be viewed with
a number of factors in mind. First, all lakes for which "recent" (1965 or
later) data were available were used to create the maps, regardless of ion
balance. Some of the values, therefore, may be in question from a purely
analytical view. Second, there exists a 16-year spread in chemical analyses
for the maps: Lakes sampled once in 1965 are not distinguished from those
sampled in 1980. In all cases, the most recent chemical measurements are used
64
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©
o 7.50
YELLOWSTONE NATIONAL PARK LAKES
Figure 16. pH map, Yellowstone National Park.
for each lake. Third, the water sources for the lakes vary, and reflect
different residence times through different watersheds. Only two of the lakes
with alkalinities <230 peq/1 have significant inlets, and most lack outflow.
The primary source of water for these dilute lakes is groundwater and snowmelt
(R. E. Gresswell, personal communication). A number of the less sensitive
lakes have significant flow-through. Finally, humic lakes, geothermally
65
-------
3 Cfc
©
&
SULFATE, //eq/l
• < 100
3 100-199
O 200-399
O > 400
YELLOWSTONE NATIONAL PARK LAKES
Figure 17. Sulfate map, Yellowstone National Park.
influenced lakes, and those fed by subterranean seeps through calcareous
deposits are not distinguished from those lakes which more readily reflect the
influence of the surficial geology. Indeed, many lakes in this geologically
active area may be influenced by unknown factors. Figure 18 shows the loca-
tion of the major thermal springs and geysers in the park (Waring 1965):
66
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111°
110-30'
M'30
Figure 18. Location of hot springs and geysers, Yellowstone National
Park (from Waring 1965).
springs and geysers in the park (Waring 1965): These are concentrated in
geyser basins along the Firehole and Gibbon rivers, as well as north of
Yellowstone Lake. Major hydrothermal activity in the park generally follows
the southwest-northeast sweep of the rhyolite plateau.
Examination of alkalinity and pH data indicates that most of the lakes
are well buffered against potential increases in rainfall acidity. One fourth
67
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of the surveyed Yellowstone lakes do report alkalinity values <230 peq/1
(defined as "sensitive" in this report), although a number of these (at least
7 of 30) receive significant internal acidity from humic acids or hydrothermal
springs. All but four of the lakes in the < 230 ueq/1 class are naturally
barren of fish.
Factors Influencing Alkalinity (Sensitivity)
Numerous investigators (e.g., Galloway and Cowling 1978) have considered
surficial geology as the critical factor in determining water chemistry of
many lakes and streams. Commonly, surficial geology is correlated with water
chemistry when soils are derived from the underlying bedrock, surface water
originates as flow of incident precipitation through a watershed, and chemical
constituents are derived primarily through ion exchange/mineral weathering
reactions occurring in the1 soil.
As a whole, lakes in Yellowstone are influenced by far more complex
factors. Three major glaciers caused the deposition of extensive allocthonous
rubble in some areas. The chemical characteristics of this transported rock
material may, in some cases, dominate lake chemistry. The ash and lava flows
covering large areas of the park are dotted with hydrothermals which provide
internal sources of sulfate and other chemicals. Underground springs,
especially in the north, may contribute large concentrations of dissolved ions
to lakes in "unreactive" bedrocks. Finally, watersheds frequently show the
effects of a number of different geologic events, making simple separation of
most lakes into "dominant" bedrock type subject to error.
Considering only lakes with good ion balances and no known humic or
thermal influence, a separate variance t-test was used to determine if signif-
icant differences existed in surface water chemistry between the volcanic and
the mixed-geology regions. The results of the pairwise comparison indicate
that the alkalinity and the base cation sum are significantly different
between the volcanic (FR, RP) and the older sedimentary-volcanic (GT, AB, BT)
regions of the park, with p_ < 0.01 (Table 19). Both alkalinity and base
cations are significantly lower in the volcanic regions. There appears to be
no statistically significant difference in lake sulfate concentration between
the two regions, indicating that local sulfur sources are not confined to a
single region, but may influence lakes in many areas of the park.
The statistical results indicate that, with the best available separation
of "poor" data (bad ionic balance, thermal or humic influence), lakes in the
68
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Table 19. Regional alkalinity of Yellowstone National Park lakes.
Mean alkalinity
Region (ueo/1) No' of samPles Range (|jeq/l)
RPa
FR
GT
AB
BT
182
320
1468
1493
1907
8
2
8
3
3
80-360
320
640-2280
240-3520
160-4800
FR = Rails River hydrologic unit, RP = Rhyolite Plateau hydrologic unit, GT =
Gallatin hydrologic unit, AB = Absaroka hydrologic unit, BT = Beartooth
hydrologic unit.
Rhyolite Plateau and Fall River basalt region (i.e., those most influenced by
volcanic bedrock) are potentially more sensitive to acidification than those
in the non-volcanic northern and eastern ranges. The term "sensitive" is, as
always, relative, for the more sensitive lakes in Yellowstone show similar
geology to the least sensitive lakes in Rocky Mountain National Park (this
study).
Alkalinity is commonly observed to decrease with increasing elevation, as
soil depth and development, and watershed residence time are decreased. A
fairly strong alkalinity-elevation correlation exists for a number of water-
sheds in Rocky Mountain National Park, with only a weak trend for the
volcanic-andesite dominated Upper Colorado watershed (Figure 8). Results for
the Yellowstone lakes dominated by rhyolitic bedrock are intermediate
(Figure 19), showing a fairly strong correlation, except for two lakes located
in deep depressions at the edge of the formation. The Yellowstone rhyolite is
a somewhat more homogeneous bedrock than the Upper Colorado geology; this may
explain the clearer gradient.
An evaluation of the relationship of sensitivity to basin characteristics
was attempted by statistical analysis of water quality data of lakes from
differing hydrologic regions. Lakes in regions dominated by volcanic bedrocks
69
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cr
O)
3.
500-1
480-
300-
300-
100 —
A A A
A A
\ I I I I I I I I I I I I I I I I I I I M I I I I I I I
2000 2100 2200 2300 2400 2500 2600 5700
ELEVATION IN METERS
Figure 19. Alkalinity versus elevation, lakes draining rhyolite bedrock,
Yellowstone National Park.
show the lowest alkalinities and base cation concentrations. On the whole,
these lakes may be considered the most sensitive in the park to acidification.
A wide spread in chemistry values for the other lakes indicates that deep
springs or local geologic deposits may greatly influence water chemistry.
Historical Changes in Surface Water Chemistry
Acidification trends may be determined in two major ways: Analysis of
historical data, and use of (empirical or mechanistic) predictive models. The
major difficulties with historical data are that (1) water chemistry may
change daily and seasonally in relation to biological activity, (2) method-
ology may change over the years, and (3) hydrological and meteorological
conditions may not be comparable. Minimization of daily and seasonal fluctua-
tions is best accomplished by holding these parameters as constant as
possible, and by comparing mean values of a number of lakes. All water
chemistry data used in this study are from the summer months of June through
September, but daily fluctuations in the chemistry were not determined, since
lakes were sampled at different times of the day from one year to the next.
Changes in methodology may be accounted for by application of "correction
70
-------
factors" if earlier methods are systematically biased (e.g., Burns et al.
1981; Pfeiffer and Festa 1980). When complete chemical analyses are avail-
able, ion balances may serve as a quality check. For the Yellowstone data,
all alkalinities were determined using colorimetric titrations, and all pH's
with either the Hach or Hellige kit. Since a single lab performed analyses of
Yellowstone Park water since 1974 and methods have not changed considerably,
data collected since that year are highly comparable.
The final difficulty with historical data is related to differing hydro-
logical and meteorological conditions. Ionic concentrations may be substan-
tially reduced by dilution during a wet period and increased by concentration
during a dry period. While absolute concentrations have changed, relative
concentrations (with respect to the sum of all ionic constituents) have not.
Figures 20 through 23 attempt to account for simple hydrologic variations in
comparing historical with recent data. The dotted line in each figure
connects the origin with the ion sum for each year. The position of each
individual ion with respect to that line indicates whether its relative con-
centration has increased (above the line) decreased (below the line) or
remained constant over the period of time indicated (from Henriksen 1982). In
Figures 20 through 23, a solid 45 degree line is included for comparison. By
indicating relative changes in surface water concentration, the plots reduce
interpretive error due to differences in hydrologic conditions. Figures 20
through 23 represent available historical data for lakes with alkalinity
values of <500 yeq/l , including those with poor ion balances (i.e., >20%
variations).
Of the seven lakes shown in the historical comparison plots, three show a
relative decrease in alkalinity (High, Crescent, Grebe) and increase in
sulfate over the 10-year period, two show the reverse trend (Wolf, Ice), and
two show no change in alkalinity (Crag, Cascade). Thus, the overall trend for
the seven lakes appears random. Two of the lakes showing alkalinity declines
are located in the extreme northwestern corner of the park in a group of five
small snowmelt-seepage lakes in the Specimen Creek watershed. These lakes
show uniformly low alkalinities; however, ion balances are poor. More
sampling would be necessary to make definitive statements about the sensi-
tivity of these lakes. Of the three lakes which show an increase in lake
sulfate, the relative sulfate concentration changes (averaging 80 [jeq/1) are
71
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CHEMICAL COMPOSITION -- 1970/1979
HIGH LAKE
YELLOWSTONE NATIONAL PARK
389 —i
aee
1
9
7
9
iee —
ION BALANCES
1970 -- 18.6
1979 -- 21.0
e —
XX
S04A / / &t
/ X
No. X -''
/ -x
KAX'''
Mga/X
^
'—[—[ 'JT III1 1 1 1 1 1 1 1 III i 1 1 1
e se lee ise aee ase aee
1978
CHEMICAL COMPOSITION -- 1970/1979
CRESCENT LAKE
YELLOWSTONE NATIONAL PARK
388 —!
aee -
ION BALANCED
1970 -- 41.6
1979 — 33.7
i i i i i i i i i i i i i i i
se i8» ise aee 259 see
lee -
Figure 20. Historical chemistry comparisons, High and Crescent Lakes. All
concentrations in (jeq/1.
72
-------
CHEMICAL COMPOSITION -- 1963/1979
GREBE LAKE
YELLOWSTONE NATIONAL PARK
599 —i
496 -
399 -
299-
199-
ION BALANCES
1963 -- 7.5
1979 -- 4.4 e
1963
CHEMICAL COMPOSITION -- 1969/1979
WOLF LAKE
YELLOWSTONE NATIONAL PARK
488 —i
369-
299-
199 -
ION BALANCES
1969 -- 7.9
1979 2.8
-i—i—i—i—I—r
166
AAlk.
269
1969
366
496
Figure 21. Historical chemistry comparisons, Grebe and Wolf Lakes. All
concentrations in peq/1.
73
-------
CHEMICAL COMPOSITION — 1969/1980
ICE LAKE
YELLOWSTONE NATIONAL PARK
259—1
aee -
ise —
168 -
se —
ION BALANCES
1969 -- NOT
AVAILABLE 8
1980 -- 0.4
1 ' ' ' I ' ' ' ' I ' ' ' ' '
188 158 288 258
1968
CHEMICAL COMPOSITION -- 1970/1979
CRAG LAKE
YELLOWSTONE NATIONAL PARK
S88 —1
158 -
180 —
ION BALANCES
1970 -- 69.9
1979 28.2
58-
1978
Figure 22. Historical chemistry comparisons, Ice and Crag Lakes. All
concentrations in peq/1.
74
-------
ION BALANCES
1969 -- NOT AVAILABLE
1978 14.7
CHEMICAL COMPOSITION -- 1969/1978
CASCADE LAKE
YELLOWSTONE NATIONAL PARK
I—I—I—I—I—I—I—1 I
Figure 23. Historical chemistry comparisons, Cascade Lake. All
concentrations in peg/I.
considerably greater than the sulfate load in precipitation (approximately 33
ueq/1). These sulfate changes are probably too great to be caused by acid
precipitation and likely reflect the influence of local natural sources of
sulfate.
The relative concentrations of sulfate and alkalinity were also computed
for the seven lakes and are shown in Table 20. Comparing data in terms of
relative concentrations, or percent of each ion in relation to the total ion
sum, is another method to minimize the influence of sampling under different
hydrologic conditions. t-tests on historical versus recent relative concen-
trations of alkalinity and sulfate for the seven lakes show no significant
changes in these parameters over time.
Predictive models, such as that developed by Henriksen (1979), generally
assume that bicarbonate lost in water acidified by atmospheric deposition is
stoichiometrically replaced by sulfate, as strong acids from anthropogenic
75
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Table 20. Relative concentration9 of alkalinity and
sulfate, lakes with historical data.
Lake
Crescent
High
Cascade
Ice
Crag
Wolf
Grebe
X
Alkal
Historical
(1963-70)
47.2
36.1
33.3
18.6
40.2
27.5
45.3
35.5
i n i ty
Recent
(1978-80)
27.8
20.1
30.0
36.2
41.2
35.6
35.8
32.4
Sulfate
Historical
(1963-70)
11.3
8.4
12.7
28.8
24.4
17.3
5.1
15.4
Recent
(1978-80)
25.2
20.9
16.9
9.1
10.7
12.3
13.2
15.5
Relative concentration = [ion of interestj/ion sum x 100.
sources titrate existing alkalinity or replace bicarbonate as a major weather-
ing ion. This assumption implies a negligible increase in base cation release
from soils with acidification. A second assumption is that "internal" natural
sources of sulfate are negligible. However, Figures 20 through 23 indicate
that historical changes in alkalinity are generally balanced by changes in
both calcium (cation compensation for acidity increases) and sulfate, in
violation of the first assumption. The second assumption is also invalid for
Yellowstone, which is heavily influenced by numerous geothermal sources of
sulfur. This may be illustrated by comparing the concentrations of chloride
and sulfate among the Yellowstone lakes: chloride (Figure 24), assumed to be
a conservative ion, remains relatively constant in nearly all the Park lakes.
In this plot, four of the five outliers represent large, old lakes (three
samples from Yellowstone Lake and one from Lewis Lake); these are probably
influenced by long-term concentration by evaporation. In contrast, sulfate
76
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CHLORIDE VS. ALKALINITY
YELLOWSTONE NATIONAL PARK LAKES
258-1
150-
Q
O
50-
A
A
A
A A AA A A A
A
A
A A
i i fti^j i i i i | i i i i | IM i ftp i i i | n i i | i i i i |
250 500 750 1000 1250 1500 1750
ALKALINITY IN yeq/1
Figure 24. Chloride versus alkalinity, Yellowstone National Park lakes.
concentration throughout the Park lakes is highly variable (Figure 25). In
Figure 25, a cluster of 17 low sulfate, low alkalinity lakes (mean sulfate
concentration = 35.8 ueq/1) is evident in the Park, along with a wide scat-
tering of higher sulfate lakes. Thus, the unique characteristics of
Yellowstone make use of a Henriksen-like predictive acidification model
inappropriate.
Detecting historical changes in surface water chemistry for Yellowstone
is confounded by natural variability in water chemistry, internal sources of
acidity, and a scarcity of reliable historical data. Yellowstone precipita-
tion is currently not highly acid, nor do the lakes appear acidified by
anthropogenic activity. No significant overall change in water chemistry was
noted from lakes sampled once, then resampled several years later. The dilute
lakes in the rhyolite plateau and also in the far northwestern corner of the
Park may be the most subject to future acidification.
77
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SULFATE VS. ALKALINITY
YELLOWSTONE NATIONAL PARK LAKES
400 —i
cr
0)
300 —
200 —
100 —
A
A
A
AAA^AAA
W& AA A
A
A
A A
A
A A
A A
I II I I I I I I I II I I I I I I I I I I I I I I I I I I I I I I |
250 500 750 1000 1250 150e 1750
ALKALINITY IN ueq/l
Figure 25. Sulfate versus alkalinity, Yellowstone National Park lakes.
Current Status and Future Trends in Surface Water Chemistry
Current, historical, and future acidification scenarios depend upon
changing composition of precipitation. Yellowstone receives an average of
42 cm of rainfall annually (NOAA 1970), but, because of the Park's great size
and varied terrain, precipitation distribution is not homogeneous. The
Continental Divide intercepts eastward moving storms from the Pacific, causing
the greatest amount of precipitation near the Divide in the southwest, and the
lowest in the low altitudes. Up to 1.2 m of snow may accumulate in the Park
on average winters. Figure 26 indicates how weekly averaged pH and sulfate
concentrations over the NADP deposition-monitoring site vary with season from
June 1980 to January 1982. Although no overall trends are evident, chemistry
is quite variable, with a few sharp sulfate peaks over the year. These high
peaks represent the lowest volume periods of the record, and are not corre-
lated with especially low pH.
In 1981, weighted average precipitation pH at the NADP collecting station
was 5.2 and weighted average annual sulfate concentration was 33.5 ueq/1.
78
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PRECIPITATION CHEMISTRY
YELLOWSTONE NATIONAL PARK
8 —
6 —
2 —
i |
t I
I \ > 9
t •': ; \ * ?** '
1 f : . •' * ' J * • * J
• ;'• it/ : * ; •:,' V ••'. »
1 ' l . , i * • , , 1 4 " '
* ;• * • . T . «t; * ;; I
i/'u'U l ^ . -i
i' ' . i
!4... . u I
. * * PH »l
•I »— » SULFATE T||
/jji / . rl j'l!
' I/^V f y / V/V^fl '
J * i ' / i N l|l
4 * ^ 4
1 ! 1 1 1 1 1 1 1 1 1 1 I 1 1
JAgONDJFFIAnjJAS
t
1
t
1
'» ^
(
1
u 1
v , -i
0 N I
'
*
f
1
1
)
l\£
J F
-
15»
— iee
— se
1980-1982
Figure 26. Precipitation pH and sulfate concentration, Yellowstone National
Park, WY, 1980-1981 (from NADP 1981).
During the same year, over a "typically" acidified area of the eastern U.S.,
Hubbard Brook, New Hampshire, precipitation pH averaged 4.4 and precipitation
sulfate averaged 48.9 peq/l. A comparison of these two sites indicates that
the northwestern Wyoming area is currently not threatened by highly acid
precipitation.
The major anionic contributor to strong acidity is the sulfate ion.
Although sulfate mobility can be affected by soil adsorption and biological
uptake (Johnson and Cole 1980), inputs and outputs of this ion have been found
approximately equal in a number of lakes, such as those in the Canadian Shield
region (NRCC 1981). Long-term increases in sulfate deposition to sensitive
lakes in Yellowstone could result in increased sulfur concentration and
79
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potential acidification. As discussed previously, the mean sulfate concentra-
tion for the low sulfate-low alkalinity group of lakes was approximately 36
(jeq/1 This value corresponds well to the estimated average annual precipita-
tion input of about 33 (jeq/1 as derived from recent NADP data and may, as an
extreme, represent a 100% contribution from rainfall (no sulfate derived from
soils, bedrock, or nearby thermal sources). This simplification represents a
maximum, and ignores any potential soil sulfate adsorption and residence time
considerations.
Yellowstone does not currently receive acid precipitation comparable to
the eastern United States. The low sulfate concentration of 36 peq/1 falls in
the range of "background" sulfate for the Canadian Shield lakes (30-60 peq/1),
and probably is also almost entirely of natural origin. This is further
corroborated by the relatively high rainfall pH. In contrast, lakes and
streams in acidified regions throughout the U.S. and Canada show average
sulfate ranges of 3 to 4 times that (Table 21). The higher values of sulfate
found in some Yellowstone lakes is assumed due to groundwater, soil, bedrock,
or geothermal sources. Yellowstone probably experiences little current acidi-
fication from acid precipitation. Considering the highly variable lake
sulfate concentrations, however, local sulfate sources undoubtedly pervade the
park. Given the existence of geothermal, local atmospheric, bedrock, and
underground spring sources of sulfate, it is impossible to state how anthro-
pogenic acidification will affect these lakes.
Table 21. Sulfate levels in selected acidified waters.
Area Sulfate range (jjeq/l ) Reference
Southern Ontario (lakes) 160-220 Dillon et al. (1978)
Nova Scotia (lakes) 100-140 NRCC (1981)
New Hampshire (streams) 129-142 Likens et al. (1977)
It is possible, however, to approximate how Yellowstone would be a-ffected
if rainfall over the park were to change composition to approximate the
acidity of typically eastern precipitation. The monitoring station at Hubbard
80
-------
Brook experimental forest provides the longest continuous record of precipita-
tion chemistry in the United States. Over the ten year period from 1963 to
1974, the weighted annual mean concentration of sulfate in precipitation was
60.3 [jeq/1, and for nitrate, 23.7 peq/1. A far shorter record (1.5 years) is
available for the evaluation of precipitation chemistry of Yellowstone
National Park, however, a value of approximately 30 ueq/1 sulfate and 10 ueq/1
nitrate is reasonable (NADP 1981). Thus, a doubling of the sulfate and
nitrate concentration of Yellowstone precipitation from approximately 40 to 80
ueq/1 would roughly yield the mean precipitation chemistry for these constit-
uents in the east. Two extremes exist in the response of watersheds to this
chemical change. As a minimum, all of this new sulfate and nitrate would be
incorporated into the watershed, i.e., adsorbed onto soil particles or tied in
biotic cycling. As a maximum, all of the new strong acid-derived anions would
be introduced into the lake ecosystem. Thus, the range of acidification of
Yellowstone lakes would be from 0-40 |jeq/l. The maximum loss of alkalinity
expected, under these conditions, is 40 ueq/1; the true loss is probably
somewhat less. A loss of 40 peq/1 alkalinity from each lake in Yellowstone
would shift the number of "sensitive" (alkalinity <230 peq/1; no significant
hot springs) lakes from 24 to 33. Only one of these new lakes has a signifi-
cant trout population, the rest are historically barren.
81
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FISH POPULATIONS
INTRODUCTION
The loss of fish populations in acidified lakes and streams has been the
most publicized effect of acidic deposition. Although it is believed that
other aquatic biota are also unfavorably affected by increasing acidity..
effects on fish have been the most widely studied and documented. The basis
for the RMAS was to determine if, in fact, there was any evidence that the
acidification of waters in the most sensitive areas of the Rocky Mountain
region had progressed to a point that might endanger any of the fish species.
The evaluation relied on the acidity and alkalinity data from RMNP and YNP and
published and unpublished fisheries information for the Rocky Mountain region.
Assessment Approach
Assessment of the potential responses of fish populations in the Rocky
Mountain region to acidification, resulting from increased atmospheric strong
acid deposition, was approached in the following manner:
1. Areas potentially sensitive to acidification were defined on the
basis of relationships between water quality, geology, and soils,
developed in representative watersheds in RMNP and YNP.
2. Information on predominant fish species, fisheries, and management
policies prevailing in potentially sensitive areas were obtained
from the published literature and unpublished fishery survey data.
3. The possible effects of acidification on the species at risk were
evaluated from published information on life history patterns, in
relation to expected changes in water quality. Potentially critical
life history stages were identified on the basis of documented
effects on species with comparable life histories and habitat re-
quirements, in regions where acidification has already occurred.
4. The implications of possible acidification effects on fish popula-
tions for State and Federal management policies were considered,
critical information gaps were identified, and future research
direction recommended.
82
-------
Evaluations in this study of water chemistry data obtained from RMNP and
YNP and data from other studies in the Rocky Mountains have not revealed any
instances of chronic acidification at levels that would be detrimental to fish
survival. Chronic acidification of surface water occurs where rates of base
supply, derived from weathering processes in the drainage basins, are exceeded
by rates of strong acid input from atmospheric depositions. Such conditions
have been observed in sensitive areas of eastern North America and Scandinavia
(Wright et al. 1980), where chronically acidified lakes and streams exhibit an
absence of bicarbonate buffering, low pH (<5.0), and increased levels of
potentially toxic metals. Fish populations are generally absent or extremely
stressed at these chronic levels of acidification (Schofield 1976; Muniz and
Leivestad 1980). However, it is important to recognize that perturbations
leading to the observed decimation of fish populations in these chronically
acidified waters probably were initiated at much earlier, transitional stages
of acidification, prior to the complete loss of bicarbonate buffering in the
systems (Henriksen 1980; Schofield 1982).
As indicated in the previous sections on water chemistry and geology, a
large number of headwater drainages in the geologically sensitive areas of the
Rocky Mountains exhibit extremely low rates of base supply, as indicated by
the low alkalinity and cation levels. These drainage systems border on a
transitional stage of acidification, at current levels of atmospheric strong
acid deposition. Even minor excursions of increased strong acid loading, as
might occur during the early stages of snow-melt, could episodically acidify
these systems. The presently available water chemistry data represent late
snow-melt or baseflow conditions, hence the contemporary occurrence of such
events is unknown. The probable consequences of such perturbations for
indigenous fish populations, should they occur in these sensitive drainage
systems, are considered in subsequent discussions of fish responses to water
quality change.
RESULTS AND DISCUSSION
Fish Resources in Potentially Sensitive Areas of the Rocky Mountains
The general areas in the Rocky Mountains potentially sensitive to acidi-
fication are situated in the alpine (>3,200 m) and upper montane (2,500-3,200
m) altitudinal zones. Sensitivity of specific drainage basins is tempered by
83
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local variations in bedrock and surficial geology, as discussed previously.
Fish species richness and standing crops are relatively low in these headwater
drainages and many were originally devoid of native fish populations, because
of natural barriers to colonization in the form of falls and stream gradients
impassible to fish. However, most of the originally barren headwater lakes
were subsequently stocked with either native or exotic salmonids, beginning in
the early 1880s (Pennak 1963). The cutthroat trout (Salmo clarki) is the only
native trout in the area and it is represented by several subspecies re-
stricted to specific drainage systems. The only other native species locally
present in these sensitive watersheds are the grayling (Thymallus signifer),
several species of the mountain sucker (Pantosteus spp.), sculpin (Cottus
spp.), and the mountain whitefish (Prosopium williamsoni). Introduced, non-
native species that have become regionally established include the brook trout
(Salvelinus fontinalis), rainbow trout (Salmo gairdneri), and brown trout
(Salmo trutta). The intentional and inadvertent introduction of these
species, particularly the brook trout and rainbow trout, has been most detri-
mental to the native cutthroat trout stocks, both because of competitive
exclusion and hybridization. Additionally, indiscriminate hatchery plantings
of cutthroat have so blurred the genetic integrity of this species, that only
in a few high lakes and streams can the original subspecies still be distin-
guished morphologically (Pennak 1963). The problems associated with the
preservation and maintenance of these subspecies will be discussed further in
the section on wild trout management, with specific reference to the water-
sheds in RMNP.
The extensive fisheries data base for YNP provides both a detailed chron-
ology of the changes in fish distribution and management policies for this
region since the 1800s. The comprehensive summary of fish stocking activities
in YNP by Varley (1981) provides the most recent, detailed information on the
status of fish populations in the Park. An earlier publication by Fromm
(1941) provides a more anecdotal account of the early hstory of fish surveys.
Although eighteen species of fish (12 native species) are currently recorded
as being present in YNP waters, their distribution is quite limited. Many of
the lakes and streams in YNP were and still are fishless, primarily because of
the physical limitations to colonization described earlier. Lakes and streams
in approximately 40% of YNP (Figure 27) were estimated to be devoid of fish in
84
-------
Figure 27. Cross-hatching shows the area in Yellowstone National Park
found barren of fishes by Jordan in 1889, with the exception of sculpins
in the Gibbon River above Gibbon Falls (from Fromm 1941).
the 1800's (Jordan 1889). Early fishery management efforts sought to estab-
lish fishes in these barren waters through extensive plantings of both native
and exotic species. Varley (1981) provides a detailed chronology of these
stocking efforts. Many of the previously fishless headwater streams and lakes
received introductory stockings during the period 1920-1935. Although fish
populations were probably established temporarily in most of these waters by
stocking the majority of the initially fishless lakes are presently barren
once again. However, this is not the case for streams. Most of these
historically fishless streams are currently supporting viable fish populations
(Table 22). The difference probably reflects the lack of suitable spawning
habitat in many of the small headwater lakes. In the previous section 23
potentially sensitive lakes were identified in YNP (alkalinity <200 ueq/1)
85
-------
Table 22. Current and historical fish population status of lakes
and streams in Yellowstone National Park (from Varley 1981).
Category
Historical Current
Fishless Fishless
Fishless Fish
Fish Fish
Unknown
Total
Number
Lakes
29
18
11
13
70
Streams
2
38
17
16
73
from the water chemistry data available for 107 lakes. Information on histor-
ical and current fish status obtained for 11 of the sensitive lakes is sum-
marized in Table 23. Only one of the lakes supported cutthroat trout histor-
ically and the only other species currently present is the introduced brook
trout in three of these lakes.
Fisheries Management Policies in Potentially Sensitive Areas
State and federal policies which must be considered in assessing poten-
tial acidification impacts on fish populations include state level wild trout
management policies, National Park Service aquatic resource management policy,
and U.S. Fish and Wildlife Service implementation of the Endangered Species
Act, including cooperative agency efforts.
The NPS policies governing the management of aquatic ecosystems in desig-
nated Natural Zones are particularly relevant to the sensitive areas identi-
fied in RMNP and YNP. The primary goal of resource management programs in
natural zones is the preservation and restoration of native aquatic eco-
systems, including those waters originally barren of fish. Park waters
falling into this category are allowed (or in some cases "rehabilitated") to
revert to their original fishless condition. This would include the majority
of sensitive waters in YNP and a large number in RMNP as well. Strict inter-
pretation and adherence to this policy would seem to make the question of
86
-------
Table 23. Total alkalinity and fish population status for sensitive
lakes in Yellowstone National Park (from this study, and Varley 1981).
Lake name
Wrangler
Summit
Shelf
Mt. Everts
Ice
Ranger
Obsidian
High
Forest
Trilobite
Robinson
Alkalinity
(peq/1)
40
60
80
160
200
160
80
170
192
200
100
Fish
Historical
Fishless
Fishless
Fishless
Fishless
Fishless
Fishless
Fishless
Fishless
Fishless
Fishless
cutthroat
Status
Current
Fishless
Fishless
Fishless
Fishless
Fishless
a
brook trout
cutthroat
cutthroat3
brook trout
brook trout
Status questionable
potential acidification one of largely academic concern, with little relevance
for fisheries programs. However, there are two important exceptions to this
policy which should prioritize concern for the potential acidification of
these waters. In some previously fishless waters, populations of either
native or non-native fishes have become well established. If these estab-
lished populations represent distinctive sub-species (particularly of endan-
gered or threatened indigenous species) or valuable genotypes of non-native
species, the populations may be designated as "naturalized" and managed as
integral components of the ecosystem. Similarly, should research indicate the
need to stock or re-locate threatened or endangered species, fishless or
87
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formerly fishless waters may be utilized as refugia for these species (Watson
1980; Jones 1980).
The relatively recent evolution and implementation of "Wild trout manage-
ment" programs (most notably, the Colorado Division of Wildlife Commission's
Wild Trout Policy, adopted in 1982) in the Rocky Mountain states is indicative
of the widespread concern for the depletion of wild trout stocks. The objec-
tives of these programs are diverse and although they are user oriented, they
share a common objective with NPS and FWS programs for the protection of
native species. Cooperative efforts are particularly evident and vital in
programs developed for the protection and restoration of endangered or
threatened species (Johnson and Rinne 1982; Behnke and Zorn 1976). Genetic
swamping, habitat destruction, and competition with introduced species are
primary reasons for the .widespread demise of native trout in the Rocky
Mountain Area (Behnke 1979). The Endangered Species Act provides a vehicle
for the restoration of these western salmonids and recovery action programs
are currently in place throughout the region. Implementation of these
programs first requires listing of the species as endangered or threatened,
which involves extensive study and documentation (Johnson and Rinne 1982). In
addition to affording the listed species protection, under the conditions of
the Act, habitats necessary for their survival are also afforded protection
from adverse alteration or destruction. How this condition might apply to
federal programs that influence the potential for acidification of these
habitats is unclear at this time. The general components of recovery plans
entail definition of the genetic purity of the population(s), survey and
monitoring of existing populations, evaluation of habitat in existing and
candidate reintroduction waters, and reestablishment of the native
populations.
Endangered or threatened Salmo species present in potentially acid sensi-
tive regions of the Rocky Mountains include several subspecies of the cut-
throat trout. These fish and their listings are given in Table 24. The life
history patterns of these species and the potential problems that acidifica-
tion might impose on restoration programs in sensitive watersheds are consid-
ered in the following section.
88
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Table 24. Endangered and threatened Salmo genotypes in the
Rocky Mountai
Common name
Greenback cutthroat3
Colorado cutthroat
Westslope cutthroat
Eastslope cutthroat
Snake River cutthroat
Rio Grande cutthroat
Gil a trout3
Arizona trout3
n Region.
Scientific name
Salmo clarki
Salmo clarki
Salmo clarki
Salmo clarki
Salmo clarki
Salmo clarki
Salmo gilae
Salmo apache
stomias
pleuriticus
subsp.
subsp.
subsp.
virginal is
States
Colorado
Colorado,
Wyoming
Montana
Montana
Wyoming
Colorado,
New Mexico
New Mexico
Arizona
Listing status
Endangered
Threatened
Endangered
Endangered
Rare
Endangered
Endangered
Threatened
Indicates nationally recognized as endangered.
Potential Impacts of Acidification on Fish Populations
The few remaining native trout populations in interior regions of the
Rocky Mountains persist only in small, isolated headwater drainages. These
native cutthroat populations prefer and function best at lower temperatures
than other species. With few exceptions, the cutthroat coexist and dominate
introduced species only in these cold, headwater situations (Behnke 1979).
Unfortunately, the displacement of these rare and endangered genotypes to
headwater drainages also makes them most susceptible to potential acidifica-
tion in these sensitive habitats. Because of the current endangered status of
these fish, the Salmo clarki complex must be considered the primary species at
risk and priority is given here to a consideration of potential acidification
impacts on these populations.
Given the restricted distributions of the subspecific cutthroat popula-
tions and the geologic heterogeneity in watershed sensitivities to acidifica-
tion in the Rocky Mountains, current juxtaposition of specific populations
89
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significantly determines their relative sensitivity to any regional increase
in acidic deposition. The risk of possible extinction, resulting from acidi-
fication, could certainly be lessened if management recovery teams had prior
knowledge of the distribution of the populations relative to specific water-
shed sensitivities to acidification. In the process of selecting new sites
for reestablishment of cutthroat populations, watershed acid neutralizing
capacity should also be considered among the selection criteria. The current
distributions of the Colorado River cutthroat (S. c. pleuriticus) and the
greenback cutthroat (S. c. stomias), relative to the marked differences in
watershed sensitivity observed in RMNP exemplify this point. The Colorado
River trout is native to the upper Colorado River basin (Figure 28) and
efforts are being made to reestablish this fish in headwater sections located
in RMNP. The greenback occupies the headwaters of the Arkansas and South
Platte drainages (Figure 29), on the eastern side of the Continental Divide.
Comparable efforts have been made to reintroduce this form into these areas of
the Park. The higher alkalinities in the upper Colorado drainage would cer-
tainly favor the maintenance of S. c. pleuriticus in the advent of increased
acid deposition, whereas the low alkalinities on the other side of the Divide
would probably not inhibit acidification of the greenback's prime habitat.
Behnke's and Zorn's (1976) prophetic suggestion that the greenback trout may
be the most vulnerable of all western trouts to extinction, would likely be
realized with acidification.
In addition to distribution, there are species specific life history
characteristics that must be considered in assessing potential sensitivity to
acidification. All of the interior western trouts of the genus Salmo have
basically similar life histories. They spawn in the spring when water temper-
atures reach 5.5-9.0°C, which can be anywhere from early April to June or
July, depending on latitude and elevation. All are obligatory stream spawners
and fry emergence occurs in early to mid-summer. Growth, maturation, and
fecundity are variable, depending on prevailing temperature regimes and pro-
ductivity of the local habitats (Behnke and Zorn 1976). The basic life his-
tory pattern outlined above is markedly different from that exhibited by
salmonid populations inhabiting waters of eastern North America and Scandi-
navia, where acidification impacts have been described (Schofield 1976; Muniz
and Leivestad 1980). The predominant salmonid species in these areas
90
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kilometers
Figure 28 Indigenous distribution of Salmo clarki pleuriticus
(from Behnke and Zorn 1976).
(Sa1ve1inus fontinalis, Salvelinus namaycush, Salmo trutta, and Salmo salar)
are all fall spawners and either stream or lake spawning may be locally preva-
lent. Fry emergence for these species is in early spring, often coinciding
with snowmelt periods when water quality is very poor in acidified areas. The
fry (particularly during and shortly after hatching) of most of these species
have also been found to be physiologically more sensitive to acidification
91
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£-iff South Platte River
NEW MEXICO
0 25
50 75
kilometers
Figure 29. Indigenous distribution of Salmo clarki stomias
(from Behnke and Zorn 1976).
than either embryos or older fish (Spry et al. 1981; Baker and Scnofield
1980). For these reasons, the early life history stages of development have
been identified as critical periods for survival in acidified habitats. Given
the different life history pattern of the western Salmo sp. and uncertain
water quality conditions that might prevail during the early life history of
these fish, under an acidification regime, it is difficult to extrapolate
92
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these findings from eastern North America and Scandinavia to the Rocky
Mountain region. Water quality conditions would be more favorable for cut-
throat fry if episodic acidification were to occur before hatching.
A more likely critical period for the headwater populations of this
species might be during late winter and early spring, prior to or during
spawning. Studies by Johnson and Webster (1977) demonstrated a marked avoid-
ance of acidic water by spawning brook trout and Flick et al. (1982) noted a
tendency for emigration of brook trout populations from lakes during episodes
of acidic snowmelt. These latter observations are particularly relevant in
terms of the known propensity for emigration by cutthroat populations inhabit-
ing headwater streams subject to unfavorable winter temperature extremes
(Bjornn 1971). According to Behnke and Zorn (1976), this was also the cause
of a failed transplant of greenback trout in the North Big Thompson River in
RMNP, where all the fish migrated downstream over a barrier during the winter
months. A dense brook trout population below the barrier made it doubtful
that the cutthroat population could sustain itself there. These behavioral
responses to adverse environmental conditions suggest a subtle, but potential-
ly devastating mechanism whereby even relatively minor acidification excur-
sions in headwater trout refugia could lead to population extermination.
Behavioral studies would be needed to define thresholds of acidification that
induce avoidance in the form of downstream migration. It is quite likely that
these thresholds (e.g., in terms of pH change) would be much lower than those
determined by classical bioassay for definition of dose-response functions,
where response is death or acute physiological stress.
As noted above, the relevance of any discussion of species specific
dose-response functions, as usually defined, is somewhat questionable at this
point, given the uncertainties in determining critical life history stages and
population/community level responses. However, there are some potentially
important, physiological level questions that need to be considered in defin-
ing the sensitivity of this species to acidification. Most comparisons of
relative tolerance to acidity among salmonid species indicate that the rainbow
trout (which is closely related to the cutthroat) is the most sensitive to low
pH (Haines 1981). However, no studies have yet been conducted with the cut-
throat to define its relative tolerance. Intraspecific variation in acid
tolerance to acidity has been observed in brook trout (Flick et al. 1982) and
93
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brown trout (Gjedrem 1976), and the marked polytypic character of S. clarki
(Trojnar and Behnke 1974) suggests that it might also exhibit significant
variation in acid tolerance among the defined subspecies. Determination of
the extent of this variation in acid tolerance among the extant populations in
the Rocky Mountain region would be potentially useful for rehabitation pro-
grams, in the event of acidification.
The potential for aluminum mobilization by acidification in Rocky
Mountain watersheds is uncertain, but probably not as great as in eastern
forested systems where soils exhibit marked accumulations of amorphous forms
of aluminum that are readily mobilized by acidic deposition (Cronan and
Schofield 1979). The enhanced toxicity of acidified waters containing alum-
inum is well documented (Schofield and Trojnar 1980) and if aluminum mobili-
zation is not an integral facet of the acidification process in Rocky Mountain
soils, then comparisons of biological responses between the two areas would be
further complicated by significant differences in solution chemistry.
Another important difference in solution chemistry between Rocky Mountain
waters and those of eastern North America are the levels of dissolved calcium.
The low calcium levels in the headwaters of the Rockies are more similar to
the alpine waters of Scandinavia, than those of eastern North America. The
significance of calcium as a mediator of gill membrane permeability and acid
stress was noted by Brown (1981). Below 1 mg/1 of calcium (typical for many
of the Rocky Mountain headwaters) trout would be susceptible to acid induced
osmoregulatory stress at much higher pH levels than populations inhabiting
higher (>2 mg/1, typical for eastern waters) calcium waters. However, poten-
tial adaptation (acclimation) of resident trout populations to low calcium
environments might ameliorate expected acid stress responses (Guthrie 1981).
Again, it is difficult to generalize dose-response function when dealing with
fish populations that have evolved under unique environmental conditions. The
intraspecific genetic diversity of Salmo clarki is quite remarkable, but the
potential adaptability of the genotypes of acidified environments remains to
be determined.
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CONCLUSIONS
INTRODUCTION
This section summarizes the conclusions reached concerning the four major
objectives outlined in the introduction. The first two sections are specific
to the two areas studied, RMNP and YNP. The third section evaluates the
results of the water chemistry studies in terms of effect on several species
of fish important to this region. Finally, the assessment of sensitivity of
lakes and streams to acidification in the Rocky Mountain Region in general is
based on studies in each of the two Parks.
ROCKY MOUNTAIN NATIONAL PARK
Soils and Geology
1. The soils of the Rocky Mountain National Park at the higher eleva-
tions (above 9,000 feet) are only slightly developed. They have
surface organic horizons in some cases and usually have a darkened
A-horizon underlain by slightly weathered material derived from
granite, diorites and other rocks low in bases. The soils are
coarse, low in clay, low in base cations and relatively acid (modal
pH 5.2). The organic matter provides most of the cation exchange
capacity and there is no evidence of sulfate adsorption capacity.
2. The physical properties of these soils—coarse, high in sand, low in
clay, and steeply sloping—promote rapid movement of water to the
streams and lakes.
3. The low base saturation, low pH and low cation-exchange capacity
provide little opportunity for neutralizing the acidic inputs or
providing significant alkalinity to the water system.
4. The soil itself is probably resistant to rapid acidification due to
the abundance of relatively unweathered minerals.
Surface Water Chemistry
1. Primary mineral weathering appears to be the dominant mechanism
determining the concentrations of base cations, silica and alka-
linity throughout the Park. Factor analysis shows that the primary
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mineral weathering of oligoclase and biotite accounts for almost 50%
of the variance in stream chemistry in areas underlain by granite
and biotite gneiss and schist. In areas that contain tertiary
intrusive bedrock, the mineral weathering of mafic materials, sulfur
bearing minerals, and oligioclase account for more than 50% of the
variance in stream chemistry.
Atmospheric deposition is the primary source of chloride and nitrate
in the streams of the Park. Atmospheric deposition is also the
primary source of sulfate in the Park waters, with the exception of
the Upper Colorado and Upper Fall River basins where the weathering
of sulfur bearing minerals is a source of sulfate. Chloride and
sulfate are relatively constant with elevation, while nitrate con-
centrations are highest above the timber!ine, where biological
activity is lowest. Atmospheric deposition is also a significant
source of streamwater Cn, a result of deposition of airborne dust
and salts from the dry, windy, regions upwind of the Park.
Most of the waters in the study watershed have alkalinities of <100
peq/1. The alkalinities are lowest at higher elevations. The
waters of Glacier Gorge and Ypsilon Creek are extremely sensitive.
Those of Roaring River and Upper East Inlet watersheds are very
sensitive with alkalinities of <100 p.eq/1. The waters of Lower East
Inlet and the higher elevations of Upper Fall River watersheds are
slightly higher with alkalinities <200 peq/1. The waters in the
lower elevations of Upper Fall River watershed are non-sensitive
with alkalinities >200 p.eq/1.
Based on the current concentrations of sulfate, nitrate, base
cations and alkalinity we estimate that the waters of Glacier Gorge,
Loch Vale, East Inlet and Ypsilon Creek watersheds may have suffered
a small loss of alkalinity (<10 ueq/1). We estimate that the waters
in the Upper Colorado, Upper Fall River and Roaring River watersheds
have suffered no loss of alkalinity.
If precipitation in Rocky Mountain National Park becomes as acidic
as in the eastern United States, we estimate that in the worst case
(i.e., if the increase in acidic deposition does not cause an
increase in base cation loss from the watershed), most of the lakes
in Rocky Mountain National Park will become acidified below pH 4.7.
At the other extreme, if for every peq/1 increase in acid sulfate in
the waters there is a 0.4 peq/l increase of base cation in the
waters, we estimate using the Henriksen nomograph that the majority
of lakes will become transitional and only a few will reach acid
status. The low ion-exchange capacity of the soils in the Park and
the resistance of the bedrock to chemical weathering indicates that
the increase in base cation concentrations with increased acidic
deposition in the Park will be low and that with increasing acidic
deposition many of the lakes will shift from a bicarbonate towards
an acid status.
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YELLOWSTONE NATIONAL PARK
1. The region-chemistry t-tests and alkalinity-elevation plot showed
that, after other influences are accounted for, surficial geology
and elevation are correlated to water chemistry. Rhyolite, the
dominant bedrock formation in the park, appears to be the most
sensitive (conferring the least buffering capacity), although the
subalpine (mean elevation = 2651 m) lakes located in the andesitic-
volcaniclastic rocks of the northwestern corner also may be poten-
tially sensitive.
2. Lakes found in other regions of the park—the andesitic Absaroka
Mountains, the mixed metamorphic Gallatin and Beartooth ranges--
appear not immediately sensitive to acidification by acid precipita-
tion (alkalinities generally above 500 ueq/1). These findings are
corroborated by a streamwater chemistry study in the Absaroka
Mountains (Miller and Drever 1977b), where mean alkalinity for 14
stream samples in the Shoshone River Basin was found to be 650
ueq/1.
3. Finally, no clear trends in surface water chemistry appear from
examination of historical data. It is suggested that if any chem-
istry changes have occurred at all, these are limited to the north-
west corner lakes. Since estimated "baseline" (precipitation-
derived) sulfate levels in Yellowstone lakes are still fairly low in
comparison to those levels in known acidified lakes throughout the
continent, any acidification that has occurred is minimal. Most of
the park lakes appear well protected from acidification in the
future. For the present, the dilute lakes of the rhyolite bedrock
and Fall River basalt region, as well as the Specimen Creek drainage
basin lakes, are most vulnerable to changes in chemistry by acid
rain.
EFFECTS OF CURRENT AND FUTURE ACIDIFICATION LEVELS IN FISH POPULATIONS
IN YELLOWSTONE AND ROCKY MOUNTAIN NATIONAL PARKS
1. Currently, there is no evidence of chronic acidification in Rocky
Mountain waters that would be detrimental to fish survival.
2. The very low base cation concentrations observed in the headwater
drainages of RMNP suggests extreme sensitivity to acidification.
Fish populations present in these low calcium waters may be particu-
larly susceptible to osmoregulatory stress from episodic acidifica-
tion.
3. The few remaining native trout (Salmo clarki) populations located in
interior regions of the Rocky Mountains persist only in small,
isolated headwater drainages. The cutthroat coexists with and
dominates introduced species only in cold, headwater situations.
Displacement of these rare and endangered genotypes to headwater
drainages also makes them most susceptible to potential acidifica-
tion in these sensitive habitats.
97
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4. Although a large proportion of the headwater lakes in YNP and other
areas are historically fishless, and many are still in that condi-
tion, these waters represent potentially invaluable refugia for the
reestablishment of endangered species.
5. Comparisons of alkalinity and bedrock geology in the upper Colorado
and eastern Divide drainages in RMNP, suggests that the greenback
trout (Salmo clarki stomias), which occupies the latter basins, is
at potentially greater risk than the Colorado River cutthroat (Salmo
clarki pleuriticus).
6. A comparison of the life history patterns of the western Salmo with
eastern salmonids, in relation to seasonal changes in acidity,
indicates that different life history stages may be impacted by
acidification. Hatching and fry development have been identified as
critical periods for the fall spawning eastern salmoids. However,
early-late summer emergence of fry in the western Salmo populations
(spring spawners) indicates this may be a less critical life history
stage.
7. Avoidance response, in the form of downstream emigration, to epi-
sodic acidification in headwaters occupied by J>. clarki is suggested
as a more subtle, but potentially devasting impact of acidification
in the Rocky Mountain watersheds.
8. The relative sensitivities of the cutthroat genotypes to acidifica-
tion stress, capacities for adaption in low calcium water, and
dose-response functions are currently unavailable.
SENSITIVITY EVALUATION OF THE CENTRAL ROCKY MOUNTAIN REGION
The examination of the geochemistry of Rocky Mountain National Park has
shown that many areas in RMNP are sensitive to acidic deposition and that this
sensitivity is primarily determined by bedrock geology. In addition, sensi-
tivity varies inversely with elevation in watersheds with consistent geology.
The results of the evaluation of the existing data in YNP, though not so
definitive, corroborate the general findings in the RMNP studies. An evalua-
tion of the sensitivity of the Central Rocky Mountains (Colorado and Wyoming),
using geologic maps and elevation, can be provided based on this information.
The analyses in RMNP show that watersheds underlain by granite and bio-
tite gneiss and schist are equally sensitive to acidic deposition. The lakes
and streams in these watersheds had alkalinities <200 (jeq/1 , while the waters
at higher elevations (>3300 m) were very sensitive (alkalinity 1 100 ueq/1).
The Upper Colorado River Basin and the Upper Fall River Basin contain tertiary
intrusive rocks in their drainage, resulting in low (alkalinity >200 ueq/1)
98
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sensitivity. In YNP, low-alkalinity or sensitive lakes were found in regions
underlain by rhyolite flows or basalt and andesitic-basaltic flows (USGS 1977;
Tweto 1979).
The analysis of sensitive aquatic systems in the Central Rocky Mountain
Region has been accomplished by extrapolating the results from RMNP and thus
delineates areas underlain by granite biotite gneiss and schist and similar
gneisses and schists (Figures 30 and 31). Areas underlain by these formations
are classified as sensitive (alkalinity <200 ueq/1), lakes and streams located
at higher elevations (>3300 m) can be classified as very sensitive (alkalinity
|100 ueq/1). Although areas of YNP have a limited number of moderately sensi-
tive lakes (>200 ueq/1), areas underlain by tertiary intrusive rocks are
generally classified as nonsensitive (alkalinity >200 ueq/1).
Figure 30. Spatial distribution of sensitivity in the central Rocky
Mountain Region: Colorado.
99
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'GRAND
JUNCTION
COLORADO
-------
case in the Upper Fall River Basin in RMNP. The bedrock in this basin is
primarily granite and biotite gneiss and schist. However, a small deposit of
tertiary intrusive rock at the head of the watershed gives the Fall River a
relatively high alkalinity (>200 |jeq/l). Differences in hydrologic flow path
and soil development may also dominate sensitivity on a local scale.
101
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RECOMMENDATIONS FOR RESEARCH AND MANAGEMENT
INTRODUCTION
While these studies and most others would indicate that areas of the
Rocky Mountain West were not experienceing significant impacts from acid
deposition, they also demonstrate that many headwater lakes and streams are
very sensitive (alkalinities < 200 ueg/e). It is therefore believed prudent
to undertake some long term programs to more fully assess the current status
of both deposition and surface water chemistries and to develop some long term
measurement programs. In addition strategies should be developed to protect
indigenous fish populations in the advent that this area does experience
increased sulfate and nitrate deposition. The following recommendations are
formulated to address these issues.
ROCKY MOUNTAIN NATIONAL PARK AND ROCKY MOUNTAIN REGION
1. Long term watershed experiments should be established at several
points in the Rocky Mountain Region. At minimum, routine sampling
(on at least a bi-weekly basis and in the spring, every 2 to 3 days)
should be performed. The samples should be analyzed for all major
inorganic constituents, DOC, aluminum, alkalinity and total acidity.
Based on the research of this project, we recommend that the Glacier
Gorge watershed in RMNP be considered for long-term monitoring. (As
a result of this recommendation the National Park Service is now
conducting a long-term study in the Loch Vale subbasin of the
Glacier Gorge watershed. )
2. Additional surveys of water chemistry should be performed in
mountainous areas not only in the Rocky Mountain region but also in
other mountainous areas of the western United States. It is most
probable that the acidity of precipitation will increase in future
years and it will be to our benefit to obtain background data at
this time.
3. The results from the watershed studies should be made available to
research groups having models on watershed response to acidic depo-
sition. This will ensure that if there are pecularities about
western watersheds, that the models will be developed with those
pecularities taken into account.
102
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4. Since one of the differences between the Rocky Mountain region and
other regions experiencing acid rain is the greater importance of
nitric acid relative to sulfuric acid, watershed studies should be
designed to take this into account.
5. A greater effort must be made to determine the rate of dry deposi-
tion of neutral salts (e.g., CaSCL).
YELLOWSTONE NATIONAL PARK
1. Future studies in Yellowstone National Park should concentrate on
those regions which this report has determined as potentially sensi-
tive to acidification. In particular, reliable water chemistry from
the Specimen Creek drainage basin is necessary to determine if these
lakes are indeed as dilute as indicated.
2. A more intensive sampling of the low alkalinity lakes (i.e., several
alkalinity measurements over the course of a year) would indicate
seasonal fluctuations in alkalinity and provide a more complete
estimate of sensitivity. It is suggested that the analytical tech-
nique used to determine alkalinity of these lakes be one designed
specifically for low alkalinity water, i.e., Gran's plot or double
endpoint potentiometric titration.
3. Finally, a survey of the headwater streams of the Park, particularly
those in sensitive regions or with important fisheries, is necessary
for a complete understanding of the response of Yellowstone to
potential acidification.
FISHERY RESEARCH AND MANAGEMENT
1. The potential sensitivity to acidification, of watersheds currently
occupied by endangered or threatened populations of S. clarki or of
watersheds considered as potential candidate sites for reintroduc-
tion, should be determined and given consideration in recovery plans
for the species.
2. Any further experiments designed to develop dose-response functions
for interior western Salmo clarki populations, should consider the
possibility of significant variations in tolerance of this polytypic
species. Additionally, these responses to acidification need to be
determined in very low calcium media, typical of the headwater
habitats of this species.
3. The behavioral responses and emigration tendencies of S. clarki
populations exposed to episodes of acidification should be deter-
mined experimentally.
4. The potential for aluminum mobilization in Rocky Mountain watersheds
exposed to increased acid deposition should be determined.
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5. Future studies of winter and spring lake and stream chemistry in
headwater catchments should also evaluate movement of trout popula-
tions, in response to chemical change.
104
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National Atmospheric Deposition Program. 1981. NADP Report: Precipitation
Chemistry; Fourth Quarter of 1980. Natural Resource Ecology Laboratory,
Colorado State Univ., Fort Collins. 342 pp.
National Atmospheric Deposition Program. 1982. Unpublished data.
National Oceanic and Atmospheric Administration (NOAA). 1970. Monthly
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National Research Council. 1981. Atmosphere-biosphere interactions: Toward
a better understanding of the ecological consequences of fossil fuel combus-
tion. National Academy Press, Washington, DC. 263 pp.
National Research Council of Canada. 1981. Acidification in the Canadian
aquatic environment: Scientific criteria for assessing the effects of
acidic deposition on aquatic ecosystems. National Research Council of
Canada Publ. 18475. 369 pp.
Norton, S. A. 1980. Geologic factors controlling the sensitivity of aquatic
ecosystems to acidic deposition. pp. 521-532. In E. S. Shriner (ed.).
Atmospheric sulfur deposition: Environmental impact and health effects.
Ann Arbor Science, MI.
0ien, A. 1979. Determination of easily soluble sulfate and total sulphur in
soil by indirect atomic absorption. Acta Agriculture Scandinavica 29:71-74.
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Colorado. U.S. Geological Survey Map 1-1291.
Pennak, R. W. 1963. The Rocky Mountain States, pp. 349-369. In D. G. Fry
(ed.). Limnology in North America. Univ. of Wisconsin Press, Madison.
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110
-------
Schofield, C. L. 1976. Acid precipitation: Effects on fish. Ambio
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Ill
-------
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112
-------
APPENDIX A
SOIL AND WATER CHEMISTRY SAMPLING SITE MAPS,
ROCKY MOUNTAIN NATIONAL PARK
113
-------
ROCKY MOUNTAIN NATIONAL PARK
Figure A-l.
RMNP
Soil and chemistry sampling sites in Upper Colorado basin,
114
-------
en
2813
Water
, Soils
SCALE IN KILOMETERS
0 I 2 3
ROCKY MOUNTAIN NATIONAL PARK
Isolation
x
Peak
Figure A-2. Soil and chemistry sampling sites in East Inlet basin, RMNP.
-------
MA
MC
• Water
A Soils
SCALE IN KILOMETERS
0 I 2
ROCKY MOUNTAIN NATIONAL PARK
Longs
Peokx
Figure A-3. Soil and chemistry sampling sites in Glacier Gorge basin, RMNP
116
-------
GA
GC
ROCKY MOUNTAIN NATIONAL PARK
Figure A-4. Soil and chemistry sampling sites in Fall River basin, RMNP.
117
-------
APPENDIX B
SOIL LABORATORY PROCEDURES, PROFILE DESCRIPTIONS AND CHEMICAL ANALYSES
SOIL LABORATORY ANALYSIS PROCEDURES
Cation Exchange Capacity
Extractable acidity. To 10 g of air dry soil add 100 ml of extraction
solution (BaCl2, triethanolamine). Stopper, shake well, and let stand over-
night. Run blank. Filter, wash with extracting solution. Bring up to 250
ml. Add indicator (bromcresol green and methyl red) and titrate with 0.2 N
HC1 to pink orange end-point. Calculate. (Black 1965)
Base extraction. Use macerated paper in 60 ml fritted glass funnels.
Extract with a total of 100 ml 1 N ammonium acetate pH 7.0 (allow to sit
overnight in 30 ml extracting solution). Run Ca, Mg, K, and Na on extract.
Calculate C.E.C. and report in meq. Calculate percent base saturation.
(Black 1965)
Potassium:
mi n at
1975)
200
1.5
opm.
g soil in
Filter.
15 ml of 1 N ammonium acetate, pH 7.0. Shake 5
Read on AA. Compare with standards. (Carson
Calcium and
7.0. Shake !
(1500 ppm).
(Walsh 1971).
magnesium: To 1.5 g soil add 15 ml IN ammonium acetate pH
at 200 opm and filter. Dilute wfth Lanthanum Chloride
on AA Spectrophotometer. Compare with standards.
mm
Read
Sodium: To 5 g soil add 15 ml IN ammonium acetate pH 7.0.
at 200 opm. Do not filter. Read supernatant liquid on AA
tometer. Compare with standards. (Walsh 1971).
Shake 5 min
Spectropho-
Organic Matter
Oxidize with potassium dichromate and cone, sulfuric acid by standing for
min; add water, phosphoric acid, sodium flouride, and diphenylamine indi-
ammonium sulfate. (Black 1965).
30
cator. Titrate with 0.5 N ferrous
1:1 soil to
pH with pH meter.
water volume. Mix
(McLean 1975).
5 seconds. Let stand 10 min. Stir, read
118
-------
Particle Size
Samples are sieved to remove particles larger than 2 mm. The remaining
sample is dispersed with sodium hexametaphosphate, placed in settling con-
tainers and subsampled at appropriate intervals with a pipette. The subsample
is dried at 105 C and weighed. (Franzmeier et al. 1977).
Loss on Ignition (LOI)
Ovendried (105 L) samples are ignited in a muffle furnace at 550 C and
the loss in weight is determined. In soils with low clay contents, the loss
is a valid estimate of organic matter. (Black 1965).
Sulfate Absorption
Soil samples (10 g) were equilibrated with 25 ml of dilute K2S04 solution
at a pH of 4.1. The solutions were initially at 1, 5 and 10 mg sulfur per
liter. After filtration the solutions were analyzed for remaining sulfate
utilizing an indirect Atomic Absorption method. (0ien 1979).
119
-------
Table B-l. Particle size distribution of soil samples.
Location3
TG-1
TG-1
TG-2
TG-4
TG-4
TG-4
AC-1
GC-1
GC-2
GC-3
GC-3
EI-1
EI-2
EI-3
EI-3
EI-5
EI-5
EI-6
BX-1
HG-2
HG-2
MN-1
IL-2
L80-1
L80-1
L80-1
L80-1
L80-1
L80-6
L80-6
L80-6
L80-11
L80-13
L80-13
LSI- 13
L81-13
L81-13
LSI- 13
L81-16
L81-18
LSI- 18
LSI- 18
YCS-1
YCS-1
YCS-1
YCS-1
Depth
(cm)
0-11
11-25
0-17+
0-5
5-11
11-24
0-8
Talus
24-50+
0-6
9.5-30
Talus
0-9
3-13
13-28+
0-16
16-31+
0-4
0-51+
0-5
5-35+
Talus
6-0
5-0
0-19
19-54
54-80
80-85+
0-18
18-50
50-80+
0-35+
Muck
Gravel
0-1
1-18
18-46
46-60+
31-42+
0-24
24-36
36-59+
4-11
11-21
21-36
45-60+
>2 mm
55
60
0
1
2
8
—
66
56
3
19
56
0
58
76
8
10
23
53
7
70
43
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Percent of less than
Sand
68
82
35
21
21
35
52
91
83
23
75
65
20
39
18
43
43
51
50
34
64
70
43
23
77
93
84
80
63
49
85
85
37
77
55
61
62
73
32
68
78
68
62
83
82
Silt
27
13
55
66
60
46
39
6
14
70
15
27
75
45
70
35
34
41
35
54
23
23
54
73
19
4
12
16
28
46
11
11
56
16
37
32
24
17
62
25
17
27
31
13
15
2 mm
Clay
5
5
10
13
19
19
9
3
3
7
10
8
5
16
12
22
23
8
15
12
13
7
3
4
4
3
4
4
9
5
4
4
7
7
8
1
14
10
6
7
5
5
7
4
3
Textural
class
SL
S
SIL
SIL
SIL
L
L
LS
S
SIL
SL
SL
SIL
L
SIL
L
L
L
L
SIL
SL
SL
SIL
SIL
S
LS
S
s-
S
SL
S
S
SIL
S
SL
SL
SL
SL
SIL
SL
S
SL
SL
S
S
See maps Appendix A.
120
-------
Table B-2. Soil chemical analyses'
Site,
I.D.b
TG-1
TG-1
TG-2
TG-2
TG-3
TG-4
TG-4
TG-4
TG-4
TG-4
AC-2
AC-3
AC-3
AC-3
AC-3
GC-1
GC-2
GC-2
GC-2
GC-3
GC-3
GC-3
GC-3
GC-4
GC-4
GC-4
GC-4
EI-0
EI-0
EI-0
EI-0
EI-0
EI-1
EI-2
EI-2
EI-2
Depth
(cm)
0-11
11-25
30-0
0-17a
Talus
3-0
0-5
5-11
11-24
24-36
5-0
0-9.5
9.5-12.5
12.5-50+3
Talus
4-0
0-24
24-50aa
5-0
0-6
6-9.5
9.5-30
4-0
0-4
4-10
10-463
5-0
0-3
3-13
13-24
24-35a
Talus
23-0
0-9
9-27c
% LOI
13.8
4.20
47.2
14.2
2.16
32.6
13.0
11.4
9.21
4.92
60.9
8.57
11.2
9.18
2.01
32.5
5.85
3.16
75.8
28.0
18.0
3.52
75.5
9.32
2.21
2.76
6.99
51.9
19.7
11.2
.
% OM
10.2
3.40
55.20
9.03
1.30
25.0
10.4
3.19
65.5
5.45
1.62
1.62
46.1
4.33
3.25
62.7
28.5
2.67
65.4
6.14
0.911
6.44
47.7
17.9
7.74
PH
6.0
5.7
5.2
4.3
5.2
4.6
4.8
5.0
5.5
5.1
4.9
5.2
5.1
5.2
5.0
4.3
4.2
4.6
4.9
4.9
5.1
5.1
4.7
4.8
4.8
Exch. Ca
14.28
3.03
6.59
6.00
5.25
4.20
0.936
0.204
9.15
1.84
1.84
1.10
31.27
2.93
1.70
0.963
0.315
0.101
14.58
4.12
1.11
2.63
7.53
3.15
2.27
Exch. Mg
2.12
0.556
0.630
0.880
1.01
0.980
0.346
0.034
3.29
0.425
0.731
0.20
6.71
0.538
0.217
0.535
0.438
0.063
2.07
0.927
0.286
0.556
1.29
0.315
0.224
Exch. K
0.366
0.119
0.305
0.181
0.194
0.875
0.334
0.075
3.52
0.209
0.060
0.095
3.58
0.169
0.072
0.672
0.467
0.058
1.25
0.633
0.101
0.311
0.937
0.086
0.040
Exch. Na
0.040
0.035
0.131
0.136
0.043
0.078
0.077
0.031
0.732
0.342
0.279
0.030
0.147
0.035
0.052
0.107
0.187
0.039
0.131
0.134
0.035
0.039
0.369
0.132
0.080
• •
Exch. H
11.42
4.35
41.10
41.27
10.28
41.88
38.31
25.95
33.86
17.44
19.93
2.44
39.47
5.75
4.48
45.29
41.03
12.13
34.07
21.80
6.17
12.13
42.06
35.04
27.46
— •
CEC
28.23
8.09
48.76
48.47
16.78
48.01
40.00
26.29
50.55
20.26
22.84
3.87
81.18
9.42
6.52
47.57
42.44
12.40
52.10
27.61
7.70
15.67
52.19
38.72
30.07
Base
sat.
59.5
46.23
15.7
14.9
38.7
12.8
4.2
1.3
33.0
13.9
12.7
37.0
51.4
39.0
31.3
4.8
3.3
2.2
34.6
21.0
19.9
22.6
19.4
9.5
8.7
Exch.
bases
16.5
3.7
7.7
7.2
6.6
6.2
1.7
0.3
18.2
2.8
2.9
1.4
41.6
3.7
2.0
2.3
1.3
0.2
18.0
5.9
1.5
3.5
10.1
3.7
2.6
-------
Table B-2. (continued)
Site,
I.D.b
EI-3
EI-3
EI-3
EI-3
EI-3
EI-4
EI-5
EI-5
EI-5
EI-6
EI-6
EI-6
EI-7
EI-7
EI-7
EI-7
SG-1
SG-2
SG-2
SG-2
SG-2
SG-3
SG-3
SG-3
BX-1
BX-1
BX-1
BX-2
HG-1
HG-2
HG-2
HG-2
D-1
D-1
D-1
D-1
MN-1
Depth
(cm)
12-7
7-0
0-3
3-13
13-28a
19-0
0-16
16-31a
0-4
4-10
10-313
20-0
0-22
22-37
37-39a
Talus
17-0
0-17
17-30
30-41a
2-0
0-5
5-24a
2"° a
0-51a
14-16
Talus
Talus
4-0
0-5
5-35a
3-0
0-11
11-21
21-48a
Talus
% LOI
75.0
60.3
29.7
5.26
2.67
68.8
6.70
5.36
19.5
4.53
5.02
18.8
11.4
3.84
3.82
6.63
34.3
3.66
4.15
7.09
69.0
4.48
5.75
40.9
5.60
6.62
5.42
50.8
19.9
5.50
48.0
11.2
4.52
4.68
4.87
% OM
55.3
59.5
27.6
2.17
60.9
5.34
4.93
17.1
12.4
1.98
3.14
31.5
2.15
2.57
38.5
2.66
2.60
38.1
3.58
2.34
52.3
18.5
2.41
31.1
7.96
1.26
3.55
pH
5.9
6.1
6.3
5.9
5.0
5.5
5.6
5.1
5.3
5.5
5.2
5.2
5.2
5.1
4.7
4.5
4.9
5.3
5.1
5.8
3.5
4.3
5.1
5.4
5.6
5.7
5.5
Exch. Ca
46.44
72.36
50.83
8.99
24.53
10.82
8.96
8.76
13.00
10.71
7.34
10.49
3.40
2.53
13.39
1.92
0.909
15.41
3.64
6.57
7.28
1.02
0.505
23.32
14.79
7.47
4.60
Exch. Mg
5.40
7.93
5.80
1.30
4.09
1.88
1.63
1.88
3.46
2.98
2.04
1.59
0.717
0.556
4.99
1.60
0.286
5.41
0.740
0.841
2.42
0.425
0.185
5.56
4.08
2.27
0.700
Exch. K
1.11
0.581
0.412
0.129
1.65
0.726
0.647
0.383
0.194
0.042
0.458
0.259
0.138
0.124
1.87
0.285
0.223
1.82
0.311
0.376
1.50
0.393
0.093
1.17
0.602
0.311
0.174
Exch. Na
0.126
0.272
0.214
0.083
0.246
0.111
0.121
0.434
0.452
0.288
0.044
0.101
0.052
0.070
0.115
0.066
0.062
0.121
0.101
0.048
0.185
0.137
0.062
0.106
0.115
0.070
0.030
Exch. H
26.37
26.81
22.43
4.73
36.82
15.09
14.88
23.48
18.20
6.23
12.45
27.40
8.95
15.42
33.33
18.29
17.47
29.55
17.47
9.66
47.20
34.87
19.5
31.2
19.3
10.89
10.99
CEC
79.45
107.95
79.69
15.23
67.34
28.63
26.24
34.94
35.31
20.25
22.33
39.84
13.26
18.70
53.70
22.16
18.95
52.31
22.26
17.50
58.59
36.85
20.38
61.53
38.89
21.01
16.49
Base
sat.
66.8
75.2
71.9
68.9
45.3
47.3
43.3
32.8
48.5
69.2
44.2
31.2
32.5
17.5
37.9
17.5
7.8
43.5
21.5
44.8
19.4
5.4
4.2
49.2
50.4
48.2
33.4
Exch.
bases
53.1
81.2
57.3
10.5
30.5
13.5
11.4
11.5
17.1
14.0
9.7
12.4
4.3
3.3
20.0
4.0
1.5
22.6
4.8
8.1
11.4
2.0
0.8
30.1
19.5
10.1
5.3
-------
Table B-2. (concluded)
Site,
I.D.b
MN-2
MN-2
MN-2
IL-1
11-2
11-2
L80-1
L80-1
L80-1
L80-1
L80-1
L80-6
L80-6
L80-6
L80-11
L80-13
L80-13
LSI- 13
L81-13
L81-13
L81-13
LSI- 16
LSI- 16
L81-16
LSI- 18
LSI- 18
LSI- 18
YCS-1
YCS-1
YCS-1
YCS-1
YCS-1C
YCS-1C
Depth
(cm) % LOI
0-4 4.64
4-40 3.45
40-50a 2.19
Talus 6.72
6-0 35.8
0-15 10.9
5-0 42.3
0-19 1.46
19-54 0.92
54-80 0.71
80-85a 0.66
0-18 3.94
18-50 1.44
50-803 0.83
0-35a 2.39
"Muck" 24.9
Gravel 5.35
0-1 5.84
1-18 2.85
18-46 2.60
46-60a 2.02
0-10 76.8
10-31 63.1
31-42a 27.0
0-24 7.98
24-36 1.14
36-59a 1.15
4-11 3.46
11-21 1.28
21-36a 1.74
45-603 1.16
0-4 38.3
36-60a 0.72
% OM
2.51
1.16
5.05
27.7
7.21
28.79
0.87
0.31
0.22
0.08
2.60
0.38
0.32
0.27
21.54
4.30
3.96
1.47
0.65
0.31
72.9
56.8
21.7
6.46
0.83
0.50
2.49
0.83
0.94
0.39
PH
4.4
5.2
5.0
5.0
5.0
5.9
5.3
5.3
5.3
5.8
6.4
6.8
6.5
5.5
4.8
5.0
5.8
5.3
5.2
5.3
5.0
4.8
4.7
6.1
6.1
6.1
5.0
5.2
5.2
5.4
Exch. Ca
2.60
2.32
3.84
25.24
6.46
24.48
1.40
0.80
0.80
0.70
7.34
2.80
1.90
4.10
5.15
2.63
5.60
3.94
1.21
0.90
7.83
4.52
6.80
6.57
2.40
2.00
3.70
2.90
2.22
0.50
Exch. Mg
0.750
0.639
0.690
5.92
2.02
4.67
0.483
0.183
0.150
0.20
1.17
0.700
0.450
1.333
1.048
0.606
0.800
0.690
0.455
0.383
3.27
1.75
2.58
1.94
0.567
0.567
0.667
0.450
0.320
0.067
Exch. K
0.308
0.336
0.285
1.07
0.246
0.641
0.108
0.079
0.077
0.051
0.458
0.090
0.051
0.072
0.182
0.031
0.346
0.169
0.194
0.141
1.28
0.129
0.098
0.647
0.172
0.167
0.218
0.105
0.103
0.041
Exch. Na
0.082
0.114
0.048
0.125
0.105
0.044
0.017
0.030
0.017
0.013
0.022
0.030
0.043
0.126
0.206
0.096
0.052
0.035
0.057
0.035
0.327
0.214
0.242
0.022
0.017
0.013
0.030
0.026
0.017
0.013
Exch. H
13.02
12.13
15.42
22.85
21.38
20.13
2.65
1.02
0.611
0.407
2.91
0.814
0.204
2.65
38.15
11.10
9.16
6.58
10.28
6.31
35.00
36.75
28.72
7.19
1.42
1.22
8.14
3.46
7.40
3.46
CEC
16.76
15.54
20.28
55.21
30.21
49.97
4.66
2.11
1.66
1.37
11.90
4.43
2.65
8.28
44.74
14.46
15.96
11.41
12.20
7.77
47.7
43.36
38.44
16.37
4.58
3.97
12.76
6.94
10.06
4.08
Base
sat.
22.3
21.9
24.0
58.6
29.2
59.7
43.1
5.17
63.2
70.3
75.5
81.6
92.3
68.0
14.7
23.2
42.6
42.3
15.7
18.8
26.6
15.2
25.3
56.1
69.0
69.3
36.2
50.1
26.4
15.2
Exch.
bases
3.7
3.5
4.8
32.2
8.7
29.8
2.0
1.0
1.0
1.0
9.0
3.6
2.5
5.6
6.8
3.3
6.8
4.8
1.9
1.5
12.7
6.6
9.7
9.2
3.1
2.8
4.6
3.5
2.6
0.6
aFrom McFee (unpublished)
See maps Appendix A.
GFilm container samples.
-------
APPENDIX C
WATER CHEMISTRY DATA, ROCKY MOUNTAIN NATIONAL PARK
The raw water chemical data collected in Rocky Mountain National Park are
presented with the elevation of each sample site. Missing data are denoted by
an asterisk. Sample location maps are included in Appendix A. The sample
identification code follows:
GA Roaring River
GB Ypsilon Creek Fall River Basin
GC Upper Fall River
MA Andrews Creek
MC Loch Vale Glacier Gorge
MD Glacier Gorge
V Upper Colorado River Basin MW East Inlet
The sample code indicates whether the sample was taken from a stream (S),
lake inlet (I), lake outlet (0), or lake surface (L). Replicate samples are
denoted by an 'R1 after the sample number.
The lake inlet and stream samples were used to calculate the mean concen-
trations of the major anions and cations for each subbasin.
124
-------
Table C-l. Lake and stream pH and alkalinity data
for Rocky Mountain National Park.
Sample
ID
Eleva
F pHb
Tempc
Condd
L pHe
A1kf
Roaring River
GA01I
GA02S
GA04L
GA050
GA080
GA10I
GA12L
GA160
GA18S
GA20S
GA24S
GA26S
GA28S
GA30S
GA32S
GA32SR
GA46S
3511.30
3499.10
3511.30
3511.30
3511.30
3364.99
3352.80
3352.80
3291.84
3194.30
3169.92
3017.52
2901.70
2804.16
2621.28
2621.28
2926.08
6.23
6.95
6.63
6.50
6.50
7.05
6.03
6.19
6.08
6.65
6.47
6.30
6.40
6.09
6.14
6.14
6.00
2.0
8.0
13.0
11.0
11.5
11.0
14.0
14.0
14.0
13.0
13.0
13.5
13.0
13.0
8.0
8.0
14.0
12.7
19.2
9.6
10.2
10.6
19.2
15.8
14.3
10.0
17.1
16.0
15.1
13.5
13.2
15.4
15.4
12.3
6.45
6.98
6.81
6.66
6.66
7.09
6.70
6.89
6.98
6.96
6.78
6.96
6.87
7.01
6.97
6.87
6.83
26.0
96.0
47.0
50.0
44.0
98.0
81.0
83.0
83.0
78.0
75.0
95.0
77.0
72.0
92.0
97.0
57.0
Ypsi'lon Creek
GB02I
GB060
GB08I
GB09I
GB10L
GB120
GB14I
GB160
GB18S
GB19I
GB220
GB260
GB30L
GB320
GB34S
GB35S
GB38I
GB40L
GB40LR
GB420
3413.76
3413.76
3352.80
3352.80
3352.80
3352.80
3279.65
3279.65
3108.96
3462.53
3462.53
3462.53
3462.53
3462.53
3352.80
3352.80
3218.69
3218.69
3218.69
3218.69
5.90
5.63
5.96
6.20
6.05
5.94
6.27
6.50
—
6.41
6.41
6.58
6.83
6.78
6.12
6.17
6.45
7.00
7.00
6.83
5.0
8.0
9.0
6.0
13.0
11.0
13.0
11.0
—
11.0
8.0
12.0
14.0
13.0
8.0
8.0
8.0
13.0
13.0
13.0
—
21.3
20.9
—
19.9
19.9
21.9
21.4
11.8
16.5
19.1
20.4
22.2
19.0
22.7
20.4
15.9
15.1
15.1
15.5
6.43
6.56
6.56
6.78
6.65
6.66
6.68
6.75
6.69
6.09
6.05
6.53
6.58
6.61
6.56
6.33
6.65
6.59
6.65
6.56
31.0
31.0
35.0
66.0
42.0
42.0
60.0
54.0
63.0
16.0
19.0
26.0
34.0
38.0
33.0
28.0
33.0
42.0
36.0
37.0
125
-------
Table Ol. (continued)
Sample
ID
Eleva
F
pHb Tempc
Upper Fal
GC02S
GC02SR
GC03S
GC04S
GC06S
GC08S
GC10S
GC11S
GC12S
GC13S
GC14S
GC16S
GC18S
GC20S
GC24S
MA02I
MA02IR
MA060
MA08I
MA120
MA16S
MC02I
MC04L
MC060
MC12S
MC14S
MC14SR
MC18I
MC20L
MC220
MC24I
MC280
MC30I
MC32L
MC340
MC36S
3413.
3413.
3413.
3535.
3523.
3523.
3511.
3401.
3401.
2926.
2816.
2767.
2657.
2657.
2657.
3084.
3084.
3084.
3023.
3023.
2804.
3474.
3474,
3474.
3267
3169
3169.
3328,
3328,
3328,
3316,
3316
3108,
3108,
3108
2987
76
76
,76
68
49
49
30
57
,57
,08
,35
58
,86
,86
,86
.58
.58
.58
,62
.62
.16
.72
.72
.72
46
.92
.92
.42
.42
.42
.22
.22
.96
.96
.96
.04
0
0
0
0
6
6
6
0
0
0
0
0
6
6
6
5
5
5
5
5
6
6
6
6
5
5
6
0
7
6
6
6
6
5
5
.00
.00
.00
.00
.99
.89
.90
.00
.00
.00
.00
.00
.13
.23
.20
.66
.66
.61
.81
.77
.66
.66
.48
.55
.92
.92
.21
.00
.05
.24
.04
.51
.81
.93
.94
7.
7.
6.
6.
5.
5.
5.
10.
10.
8.
9.
9.
7.
8.
8.
Tyndall
8.
8.
12.
11.
15.
Loch
1.
9.
8.
9.
6.
6.
2.
—
11.
12.
13.
13.
19.
15.
16.
1 River
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Gorge
0
0
0
0
0
Vale
5
0
0
0
0
0
0
0
0
0
0
0
0
0
Condd
42.
42.
26.
10.
15.
39.
24.
9.
22.
23.
14.
21.
22.
14.
20.
27.
27.
23.
27.
26.
12.
53.
30.
31.
34.
29.
29.
36.
—
31.
35.
34.
38.
37.
33.
10.
2
2
5
0
0
6
8
6
5
6
6
9
1
3
4
4
4
4
0
6
0
3
9
3
1
5
5
3
9
7
5
8
1
4
0
L
7
7
7
6
7
7
7
6
7
7
7
7
7
6
6
6
6
6
6
6
6
6
6
5
6
6
6
6
6
6
6
6
6
6
6
PH6
.32
.61
.12
.88
.13
.47
.07
.65
.07
.38
.05
.21
.17
.42
.93
.36
.36
.56
.46
.77
.60
.46
.46
.98
.38
.43
.47
.04
.53
.42
.44
—
.46
.74
.66
.57
Alkf
377.0
358.0
172.0
69.0
138.0
357.0
216.0
51.0
184.0
170.0
119.0
162.0
167.0
87.0
146.0
29.0
24.0
31.0
39.0
38.0
62.0
46.0
28.0
36.0
27.0
32.0
29.0
17.0
22.0
32.0
24.0
32.0
40.0
43.0
47.0
43.0
126
-------
Table C-l. (continued)
Sample
ID
MD02I
MD060
MD08I
MD10I
MD140
MD24I
MD26L
MD280
MD32L
MD340
MD38S
MD40S
MD420
MD44L
MD460
MD48S
MD50S
MD52S
V01I
V02S
V030
V04S
V06S
V08S
V10S
V10SR
V12S
V14S
V16S
V18I
V20L
V220
V24S
V25S
V28S
V28SR
V30S
V32S
V34S
V34SR
V36S
V38S
Eleva
3535.68
3535.68
3230.88
3230.88
3230.88
3474.72
3474.72
3468.62
3413.76
3413.76
3145.54
3035.81
3035.81
3035.81
3035.81
2974.85
2865.12
2755.39
3511.30
3230.88
3499.10
3255.26
3182.11
3169.92
3108.96
3108.96
3115.06
3121.15
3121.15
3486.91
3486.91
3486.91
3230.88
3121.15
3121.15
3121.15
3133.34
3133.34
3133.34
3133.34
3133.34
3108.96
F pHb
Gl
6.10
6.15
6.22
6.21
6.34
6.17
6.82
6.49
6.89
6.90
6.47
6.44
6.51
6.48
6.61
5.97
5.88
0.00
Upper
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
6.95
6.71
6.70
6.82
9.00
6.85
7.19
0.00
6.70
0.00
0.00
0.00
0.00
0.00
0.00
6.40
Tempc
Condd
L pHe
A1kf
acier Creek
8.0
12.0
11.0
6.0
11.0
3.0
12.0
12.0
14.0
13.0
14.0
14.0
16.0
18.0
15.0
16.0
12.0
0.0
Colorado
11.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
10.0
9.0
10.0
9.0
11.0
110.0
7.0
0.0
8.0
0.0
0.0
0.0
0.0
0.0
0.0
9.0
28.0
18.5
26.7
20.8
24.4
33.7
26.6
28.2
29.3
23.9
25.5
26.5
25.7
26.5
26.3
9.9
10.1
10.1
River
10.5
76.0
30.2
29.6
53.0
56.4
46.6
0.0
72.9
64.8
52.0
18.7
41.6
41.6
45.8
0.0
64.0
0.0
0.0
26.1
0.0
0.0
48.9
22.9
5.66
5.89
—
6.09
6.56
6.52
6.66
6.66
6.65
6.52
6.63
6.52
6.79
6.66
6.75
6.73
6.73
0.00
6.91
7.93
7.38
7.62
7.61
7.69
7.58
7.61
8.03
7.56
7.44
7.29
7.72
7.65
7.58
7.69
7.76
7.76
7.33
6.56
0.00
0.00
7.78
7.20
10.0
11.0
—
30.0
52.0
33.0
38.0
35.0
43.0
64.0
53.0
54.0
47.0
50.0
45.0
65.0
65.0
53.0
85.0
682.0
280.0
242.0
427.0
607.0
375.0
366.0
580.0
374.0
361.0
146.0
342.0
341.0
357.0
367.0
480.0
480.0
202.0
50.0
0.0
0.0
443.0
189.0
127
-------
Table Ol. (concluded)
Sample
ID
MW02I
MW060
MW08I
MW120
MW15I
MW16I
MW200
MW22I
MW260
MW30S
MW32I
MW360
MW38S
MW40S
MW40SR
MW42S
MW44S
Eleva
3316.22
3316.22
3169.92
3169.92
3145.54
3145.54
3145.54
3108.96
3108.96
3084.58
3023.62
3011.42
2865.12
2889.50
2889.50
2865.12
2791.97
F pHb
5.78
8.13
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
TempC
East Inlet
7.0
11.0
12.0
16.0
8.0
15.0
16.0
13.0
15.5
0.0
0.0
17.0
0.0
0.0
0.0
0.0
0.0
Cond
13.0
12.0
11.4
10.9
8.8
10.2
9.8
9.3
10.0
11.6
12.6
10.2
12.3
15.4
15.4
14.4
13.4
L pHe
0.00
6.92
6.79
6.84
7.00
6.80
7.10
6.73
6.84
6.96
6.85
6.81
6.76
6.45
6.86
6.64
7.10
Alkf
80.0
80.0
72.0
93.0
94.0
68.0
76.0
60.0
83.0
77.0
73.0
91.0
80.0
121.0
120.0
94.0
96.0
j^Elev = elevation in meters.
DF pH = field pH in SU.
Temp = temperature in °C.
Cond = conductivity in pmohs/cm.
?L pH = lab pH in SU.
Alk = alkalinity in peq/1.
128
-------
Table C-2. Lake and stream chemistry data for Rocky Mountain National Park.
Sample
ID
Eleva
Nau
Mg
Ca
NH,
Cl
SO,
P0a
Si00
Roaring River
ID
GA01I
GA02S
GA04L
GA050
GA080
GA10I
GA12L
GA160
GA18S
GA20S
GA24S
GA26S
GA28S
GA30S
GA32S
GA32SR
GA46S
3511.30
3499.10
3511.30
3511.30
3511.30
3365.00
3352.80
3352.80
3291.80
3194.30
3169.90
3017.50
2901.70
2804.20
2621.30
2621.30
2926.10
9.70
37.67
10.79
10.05
11.27
41.06
29.75
29.41
30.45
31.62
30.62
31.32
29.97
30.54
39.89
40.50
23.97
3.45
3.48
2.66
2.71
2.86
4.30
4.42
3.50
3.91
3.45
3.22
2.58
4.07
4.07
4.02
4.35
3.94
13.41
30.20
11.44
10.45
11.93
29.54
23.21
22.46
18.51
18.93
26.83
21.64
21.48
19.83
28.64
29.29
19.01
56.64
86.83
59.43
55.14
55.79
93.76
82.19
79.69
59.53
56.54
73.30
64.07
65.32
57.98
77.30
78.14
50.85
0.39
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.05
0.00
0.00
0.00
0.00
0.00
9.36
5.50
4.37
5.05
8.10
6.35
6.29
5.98
5.78
4.65
4.09
6.26
4.80
7.50
5.58
5.98
4.60
19.39
13.60
3.32
3.31
9.93
11.97
6.05
5.79
0.35
6.84
6.47
11
00
95
77
79
31.94
44.31
24.22
27.11
30.92
38.83
34.50
33.52
37.52
36.19
31.92
29.13
32.71
32.13
38.37
37.81
32.71
0.33
0.14
0.00
0.00
0.00
0.00
0.09
0.09
0.00
0.09
0.14
0.14
0.13
0.14
0.09
0.13
0.17
40.90
144.32
35.70
32.33
29.00
142.13
97.43
95.22
101.34
105.80
112.86
94.16
112.86
116.56
147.73
145.98
97.96
Ypsilon Creek
GB02I
GB060
GB08I
GB09I
GB10L
GB120
GB14I
GB160
GB18S
GB19I
GB220
GB260
GB30L
GB320
GB34S
GB35S
GB38I
GB40L
GB40LR
GB420
3413.80
3413.80
3352.80
3352.80
3352.80
3352.80
3279.60
3279.60
3109.00
3462.50
3462.50
3462.50
3462. 50
3462.50
3352.80
3352.80
3218.70
3218.70
3218.70
3218.70
17.62
19.97
19.44
33.84
24.71
24.23
32.02
31.45
29.88
3.52
8.92
8.00
18.40
17.70
16.66
16.31
16.18
14.88
18.88
15.66
5.04
3.58
2.74
4.17
4.48
3.94
4.86
4.60
4.35
2.12
3.45
2.92
6.55
5.47
4.12
3.76
4.40
3.53
4.68
3.89
11.68
10.78
11.11
13.08
14.40
12.51
16.95
16.54
16.62
5.60
7.24
9.63
21.31
18.76
11.52
12.59
12.59
11.93
13.50
13.25
38.07
42.61
45.46
43.46
52.59
47.95
53.14
50.85
53.49
15.12
27.15
33.43
36.13
34.88
31.54
30.34
35.58
34.48
37.03
36.93
1.11
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.22
0.33
0.00
0.00
0.00
0.00
0.00
0.00
0.00
3.27
2.28
2.62
3.64
4.88
2.48
2.00
1.35
2.71
0.14
0.20
4.15
3.81
4.80
2.26
2.51
2.82
3.95
5.92
3.58
18.06
20.21
16.00
0.26
14.89
14.45
12.64
4.98
9.40
8.53
12.11
11.11
9.74
2.44
13.82
13.24
11.61
7.10
9.18
8.85
27.94
36.31
35.73
24.86
37.02
36.10
40.96
37.92
38.81
18.01
25.92
21.49
29.50
30.15
21.26
24.26
27.17
20.24
23.86
23.86
0.27
0.27
0.22
0.00
0.22
0.14
0.20
0.00
0.11
0.20
0.14
0.00
0.00
0.25
0.27
0.27
0.19
0.00
0.08
0.13
66.79
75.42
75.69
119.86
94.34
93.50
116.63
114.05
113.78
31.47
26.71
54.40
46.19
78.95
64.35
64.95
50.35
62.30
62.07
-------
Table C-2. (continued)
Sample
ID
Elevd
Nau
Hg
Ca
NH,
Cl
N03+N02
SO,
PO,
SiCL
Upper Fall River
CO
o
GC02S
GC02SR
GC03S
GC04S
GC06S
GC08S
GC10S
GC11S
GC12S
GC13S
GC14S
GC16S
GC18S
GC20S
GC24S
3413.80
3413.80
3413.80
3535.70
3523.50
3523.50
3511.30
3401.60
3401.60
2926.10
2816.40
2767.60
2657.90
2657.90
2657.90
31.75
32.84
29.49
23.10
36.93
44.98
40.06
30.58
38.76
42.85
46.54
46.41
46.46
40.45
47.11
9.23
8.80
8.31
7.80
6.29
10.54
7.95
2.84
6.68
11.33
2.33
10.28
9.72
3.09
8.21
162.11
161.12
80.97
13.25
37.52
137.75
78.75
12.59
68.30
67.48
35.63
56.04
57.93
26.74
53.16
198.15
198.00
120.56
44.66
73.95
200.20
123.80
30.84
107.53
102.30
66.82
98.00
99.70
70.96
96.61
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.11
0.55
0.00
0.00
0.00
0.00
0.00
5.81
6.52
6.43
4.20
5.84
14.27
8.80
3.55
9.93
11.31
5.56
8.55
8.26
6.68
8.21
3.06
3.18
8.66
2.27
3.71
3.00
3.37
5.35
1.74
6.27
1.00
4.63
02
29
6.81
87.62
87.89
76.21
19.43
71.40
44.25
16.68
37.83
44.83
36.98
49.70
51.82
20.11
46.04
0.00
0.00
0.11
0.36
0.09
0.20
0.00
0.30
0.02
0.00
0.09
0.00
0.00
0.09
0.14
137.62
129.34
144.12
146.22
167.00
162.97
164.23
138.95
167.98
122.48
216.43
185.88
180.11
189.23
194.93
Tyndal1 Gorge
MA02I
MA02IR
MA060
MA08I
MA120
MA16S
3084.60
3084.60
3084.60
3023.60
3023.60
2804.20
14.40
14.35
16.01
15.36
16.44
18.27
3.79
3.81
4.25
3.56
3.48
3.20
9.79
9.71
12.84
12.67
13.41
17.12
37.67
38.32
54.14
55.79
57.63
62.43
0.00
0.00
0.00
0.00
0.00
0.00
—
2.88
3.33
3.41
3.75
3.92
1.66
6.53
19.56
12.56
11.19
12.48
30.09
32.92
35.19
31.65
31.65
0.20
0.27
0.08
0.08
0.09
0.08
48.29
46.28
51.36
52.95
54.56
70.31
Loch Vale
MC02I
MC04L
MC060
MC12S
MC14S
MC14SR
MC18I
MC20L
MC220
MC24I
MC280
MC30I
MC32L
MC340
MC36S
3474.70
3474.70
3474.70
3267.50
3169.90
3169.90
3328.40
3328.40
3328.40
3316.20
3316.20
3109.00
3109.00
3109.00
2987.00
27.97
7.22
7.39
12.18
12.48
12.48
10.16
12.09
9.87
9.92
10.18
11.70
19.36
14.70
13.14
7.65
1.74
1.89
2.12
2.10
2.02
1.74
2.10
1.79
1.71
1.97
2.02
3.17
2.35
2.05
33.08
6.42
6.42
7.24
10.45
9.71
10.20
9.13
11.19
11.36
11.44
12.18
13.91
14.32
14.32
138.72
22.36
22.06
29.09
36.93
39.72
36.08
39.22
37.43
37.77
40.47
42.42
44.71
46.66
44.91
0.67
0.00
0.00
0.00
0.39
0.00
0.33
0.00
1.55
1.44
0.61
0.67
1.55
1.16
0.67
12.72
1.97
1.07
0.59
4.06
1.30
3.33
3.13
4.48
4.37
4.23
4.06
9.31
5.02
5.64
57.90
4.98
10.42
14.37
14.74
17.81
10.35
11.53
12.93
11.52
11.27
10.69
10.45
11.02
109.02
16.70
21.45
26.71
18.51
30.27
23.19
24.90
25.96
24.88
27.59
27.69
28.25
1.19
0.20
0.20
0.20
0.14
0.19
0.25
0.19
0.22
0.20
0.22
0.20
0.31
0.14
0.17
119.11
33.78
30.10
51.29
45.74
57.19
26.99
34.26
28.85
30.84
30.81
35.56
36.33
35.64
36.04
-------
Table C-2. (continued)
Sample
ID
Eleva
Nab
K
Mg
Ca
NH4
Cl
N03+N02
SO,
P04
Si02
Glacier Creek
MD02I
MD060
MD08I
MD10I
MD140
MD24I
MD26L
MD280
MD32L
MD340
MD38S
MD40S
MD420
MD44L
MD460
MD48S
MD50S
MD52S
V01I
V02S
V030
V04S
V06S
V08S
V10S
V10SR
V12S
V14S
V16S
V18I
V20L
V220
V24S
V25S
V28S
V28SR
V30S
V32S
V38S
3535.70
3535.70
3230.90
3230.90
3230.90
3474.70
3474.70
3468.60
3413.80
3413.80
3145.50
3035.80
3035.80
3035.80
3035.80
2974.80
2865.10
2755.40
3511.30
3230.90
3499.10
3255.30
3182.10
3169.90
3109.00
3109.00
3115.10
3121.20
3121.20
3486.90
3486.90
3486.90
3230.90
3121.20
3121.20
3121.20
3133.30
3133.30
3109.00
4.00
5.48
9.96
10.66
14.27
15.70
18.01
17.27
17.97
17.44
16.53
18.40
18.31
17.40
17.88
16.18
16.62
19.84
7.61
121.10
15.05
88.48
—
38.15
—
78.47
37.15
26.84
37.28
3.91
11.92
13.62
19.71
35.76
36.76
21.45
27.88
39.15
62.64
2.12
1.25
1.07
2.56
2.79
3.91
3.81
3.71
3.71
3.27
3.02
2.92
3.17
2.79
2.07
3.38
3.48
4.32
1.15
4.91
1.18
13.71
8.57
7.88
10.49
10.38
6.60
7.26
7.72
3.50
7.24
7.90
7.57
7.29
6.78
8.82
5.09
5.27
9.21
3.37
5.10
7.57
6.50
8.64
9.96
10.04
10.20
10.53
10.53
10.62
11.77
11.60
11.85
11.27
12.67
13.08
14.07
7.98
165.49
68.30
43.53
132.73
—
98.66
97.51
0.00
117.10
85.99
33.57
60.89
63.44
83.69
100.47
126.72
101.71
47.81
26.17
25.43
18.81
23.80
41.97
38.42
47.41
47.06
48.50
45.86
51.60
47.41
53.59
53.54
50.45
51.55
51.75
51.90
54.04
57.14
Upper
77.00
17.66
197.85
118.96
257.14
404.09
215.12
215.82
370.76
381.84
337.62
116.87
311.38
277.25
290.77
262.72
436.63
364.77
191.47
119.41
101.60
1.33
1.61
0.00
0.00
0.00
0.00
0.00
1.05
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Colorado River
0.00
0.00
0.72
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.72
0.00
1.16
0.00
0.00
0.00
1.33
0.00
0.00
0.00
0.00
2.09
3.50
3.75
1.41
2.31
2.79
3.92
3.55
3.41
3.50
3.41
3.41
6.46
4.01
4.43
4.03
4.91
1.69
4.68
9.76
0.08
7.42
7.33
10.44
10.24
10.52
10.01
7.93
7.64
7.36
4.40
6.15
8.83
15.09
27.13
7.98
5.84
2.20
2.82
13.72
11.53
0.18
14.43
9.95
22.39
13.81
13.19
12.32
11.98
8.13
7.64
7.63
6.42
6.50
8.81
8.32
17.72
2.13
1.63
8.32
7.03
3.60
4.81
1.71
1.52
1.44
7.92
2.40
9.45
2.73
9.06
16.92
0.92
11.34
17.13
3.29
12.37
0.79
2.31
14.49
18.86
15.66
20.36
15.57
17.03
16.03
18.47
16.01
13.91
14.93
13.33
11.66
24.53
13.26
14.85
10.39
20.47
133.30
28.63
48.22
101.88
153.12
86.60
86.01
154.24
159.93
144. 94
—
55.11
58.15
78.79
79.91
113.89
107.96
93.55
119.81
44.43
0.42
0.09
0.00
0.34
0.00
0.31
0.19
0.27
0.23
0.16
0.11
0.08
0.09
0.00
0.00
0.17
0.09
0.31
0.23
0.11
0.17
0.27
0.13
0.13
0.08
0.09
0.13
0.00
0.00
0.27
0.34
0.33
0.17
0.14
0.00
0.00
0.00
0.00
0.00
__
15.23
36.04
40.76
46.06
54.11
56.27
55.75
40.75
57.71
52.66
54.56
53.25
52.22
42.62
48.77
47.99
60.38
9.82
182.16
30.88
430.91
203.95
118.62
276.39
274.00
124.85
105.68
107.90
17.18
51.24
59.73
65.89
74.69
59.13
70.62
107.98
174.36
33.78
-------
Table C-2. (concluded)
Sample
ID
MW02I
MW060
MW08I
MW120
MW15I
MW16I
MW200
MW22I
MW260
MW30S
MW32I
MW360
MW38S
MW40S
MW40SR
MW42S
MW44S
Eleva
3316.20
3316.20
3169.90
3169.90
3145.50
3145.50
3145.50
3109.00
3109.00
3084.60
3023.60
3011.40
2865.10
2889.50
2889.50
2865.10
2792.00
Nab
16.83
15.36
20.62
20.84
37.06
27.58
25.40
26.06
22.36
23.32
24.27
23.19
24.23
30.97
32.45
42.02
28.19
K
2.25
2.53
3.48
1.38
2.20
2.33
1.61
1.64
1.94
1.94
2.25
2.56
2.33
2.89
3.22
2.97
2.48
Mg
16.79
14.98
15.55
14.98
15.63
13.74
12.18
12.51
13.99
12.59
13.91
14.48
15.22
22.55
23.04
16.05
17.03
Ca
East
119.56
104.74
96.86
71.61
75.40
73.30
66.32
65.92
68.56
63.67
68.41
70.36
70.96
90.47
92.22
58.58
75.80
NH4
Inlet
0.00
0.00
0.00
1.22
0.33
0.33
0.44
0.00
0.28
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Cl
5.61
10.55
5.25
4.88
4.23
4.94
3.92
4.20
4.99
4.20
4.01
4.46
3.67
3.53
3.55
3.19
2.93
N0,+N02
30.98
7.21
9.03
2.92
1.73
1.15
0.55
—
1.16
1.61
2.50
1.35
2.08
3.89
3.89
0.45
2.66
SO,
61.19
52.57
50.35
22.82
26.94
36.44
35.67
35.96
28.73
29.09
28.67
27.82
27.80
32.40
35.67
35.25
28.82
PO,
0.19
0.45
0.14
0.14
0.11
0.08
0.00
0.08
0.08
0.09
0.08
0.09
0.00
0.00
0.00
0.00
0.00
Si02
72.54
58.65
71.69
55.12
172.01
95.19
80.42
84.92
71.41
69.79
68.99
64.92
68.50
100.57
101.45
211.87
93.57
, L icv in meters.
All ions in ueq/1; Si02 in pM/1.
— = missing values.
-------
APPENDIX D
WATER CHEMISTRY DATA, YELLOWSTONE NATIONAL PARK
133
-------
Table D-l. Recent lake chemistry data for Yellowstone National Park Lakes.
001
002
003
004
005
006
007
008
009
010
Oil
012
013
014
015
016
017
018
019
020
021
022
023
024
025
026
027
028
029
030
031
032
033
034
035
036
037
038
039
040
041
042
043
044
045
Lake
Turbid
Beaver L
Buffalo
Wrangler
Summit
Dewdrop
Dryad
Mary
Obsidian
Shelf
Mirror
Robinson
Scaup
High
Wyodaho
Sedge
Beach
Crag
Crescent
Mt. Everts A
Ranger
Sheridan
Forest
Cygnet A
Ice
Mallard
Trilobite B
Delacy E
Delacy W
Harlequin
Cascade
Cygnet B
Cygnet C
Cygnet E
Duck
Lake of the Woods
Virginia
Wapiti
Glade
Unnamed B
Lilypad
Phonel ine
Unnamed A
Winegar
Del usion
Alk
0
40
40
40
60
80
80
80
80
80
100
100
104
120
120
130
146
160
160
160
160
160
192
200
200
200
200
220
220
220
240
240
240
240
240
240
240
240
246
280
320
320
320
320
340
Year
1977
1976
1976
1977
1977
1979
1977
1977
1980
1979
1975
1976
1980
1979
1976
1970
1970
1979
1979
1976
1976
1978
1980
1978
1980
1973
1978
1972
1972
1979
1978
1978
1978
1978
1979
1974
1974
1975
1979
1976
1976
1976
1976
1976
1971
Elev
2389
2249
2347
2396
2607
2481
2529
2519
2365
2793
2705
1981
2420
2675
2071
2484
2484
2683
2622
2211
2128
2249
2262
2530
2402
2447
2676
2596
2596
2100
2432
2530
2530
2530
2374
2348
2499
2573
2952
1981
1957
1945
1981
1969
2385
PH
4.20
5.10
6.90
7.20
6.30
6.50
6.70
7.00
6.50
6.50
6.80
5.90
6.75
7.00
6.75
7.10
6.90
6.80
7.20
6.90
7.00
8.75
7.00
6.90
7.10
6.80
7.80
6.50
6.60
5.30
7.20
6.60
6.60
6.75
6.80
6.00
6.80
7.25
7.00
6.85
7.10
6.40
7.10
7.10
7.20
Ca
419.2
698.6
39.9
39.9
39.9
79.8
59.9
99.8
119.8
79.8
39.9
79.8
109.8
159.7
79.8
68.9
79.8
119.8
159.7
99.8
79.8
174.7
79.8
134.7
548.9
379.2
159.7
49.9
119.8
119.8
254.5
159.7
119.8
119.8
119.8
159.7
199.6
279.4
159.7
199.6
Mg
361.9
279.7
8.2
8.2
16.5
123.4
16.5
16.5
32.9
41.1
16.5
41.1
32.9
41.1
41.1
19.7
41.1
57.6
41.1
57.6
123.4
24.7
41.1
32.9
181.0
123.4
41:1
131.6
41.1
41.1
82.3
0.0
0.0
57.6
57.6
41.1
123.4
197.4
82.3
82.3
Na
522.0
3654.0
26.1
30.5
30.5
60.9
39.2
60.9
34.8
26.1
52.2
17.4
60.9
78.3
47.9
30.0
30.5
39.2
21.8
34.8
213.2
60.9
174.0
78.3
26.1
365.4
156.6
230.6
200.1
178.4
91.4
74.0
95.7
104.4
78.3
108.8
82.7
104.4
204.5
82.7
K
74.7
95.6
5.9
7.9
9.2
12.8
13.3
34.0
15.3
10.2
12.3
5.6
20.5
51.1
12.5
24.0
15.3
23.0
4.6
11.0
20.5
10.2
15.3
30.7
5.1
89.5
12.8
12.8
23.0
23.0
33.2
40.9
23.0
33.8
17.9
28.9
14.1
7.7
16.9
8.7
SO,
3185.5
2290.2
41.6
20.8
20.8
124.9
20.8
20.8
114.5
41.6
20.8
20.8
52.1
124.9
41.6
73.3
41.6
145.7
62.5
41.6
229.0
43.7
20.8
50.0
41.6
374.8
135.3
20.8
41.6
41.6
20.8
187.4
41.6
20.8
208.2
41.6
20.8
124.9
104.1
41.6
Cl
138.2
2482.5
28.2
25.4
36.7
36.7
39.5
42.3
42.3
14.1
28.2
28.2
42.3
22.6
28.2
4.2
19.8
31.0
0.0
28.2
141.1
42.3
39.5
25.4
28.2
2.5
53.6
48.0
33.9
39.5
28.2
0.0
0.0
28.2
28.2
28.2
28.2
28.2
28.2
28.2
Sum of
cations
1377.8
4727.9
80.1
86.5
96.1
276.9
128.9
211.2
202.8
157.2
120.9
143.9
224.1
330.2
181.3
142.6
166.7
239.6
227.2
203.2
436.9
270.5
310.2
276.6
761.1
957.5
370.2
424.9
384.0
362.3
461.4
274.6
238.5
315.6
273.6
338.5
419.8
588.9
463.4
373.3
Ion
balance
-82.8
-1.8
-31.3
0.3
-20.0
13.6
-8.5
38.4
-15.5
14.7
-20.8
-3.5
12.2
21.0
-4.6
-44.2
-28.2
-33.7
2.1
-12.3
-19.3
-2.7
17.5
0.4
95.3
46.3
-14.7
31.6
19.6
12.1
45.9
-43.5
-16.6
8.8
-55.2
-3.3
12.9
21.8
2.4
-4.3
-------
Table D-l. (continued)
OJ
en
046
047
048
049
050
051
052
053
054
055
056
057
058
059
060
061
062
063
064
065
066
067
068
069
070
071
072
073
074
075
076
077
078
079
080
081
082
Lake
Fern
Pocket
Wolf
Cygnet D
Hering
Trilobite C
Ribbon
Grebe
Tanager
YS W Thumb
Riddle
YS SE Arm
YS S Arm
Shoshone
YS Steve Island
Sylvan
Lewi s
Panther Creek
Heart
Alder
Goose
Mt. Everts B
Beula
Gooseneck
Pass
Trilobite A
Upper Gooseneck
Lost
Sportsman
Grizzly
Rainbow M
Divide
Gal latin
Outlet
Basin Creek
McBride
Squaw
Alk
360
360
360
380
400
400
440
480
500
524
540
557
557
574
574
600
639
640
716
720
760
760
800
840
840
880
900
960
1040
1080
1340
1400
1440
1480
1580
1600
1680
Year
1975
1972
1979
1979
1973
1978
1972
1979
1973
1980
1979
1980
1980
1980
1980
1978
1980
1979
1980
1976
1979
1976
1973
1979
1974
1978
1979
1980
1974
1979
1974
1970
1979
1978
1979
1975
1979
Elev
2513
2470
2438
2530
2250
2713
2384
2448
2125
2357
2413
2357
2357
2375
2357
2563
2372
2591
2271
2363
2198
2217
2249
2241
2793
2650
2240
2034
2357
2289
1793
2207
2693
2362
2253
1999
2372
PH
5.60
6.80
7.40
6.60
7.10
8.30
7.00
7.20
8.00
7.40
6.80
7.40
7.80
7.30
7.40
7.60
7.40
6.50
7.60
8.20
8.00
8.10
7.20
7.20
9.00
7.80
7.80
6.50
8.50
7.80
9.00
9.20
8.40
9.40
8.10
9.20
7.40
Ca
299.4
239.5
259.5
279.4
239.5
319.4
239.5
279.4
259.5
249.5
279.4
319.4
188.0
479.0
294.4
399.2
239.5
439.1
469.1
598.8
479.0
344.3
598.8
848.3
698.6
598.8
930.1
548.9
499.0
1297.4
1247.5
598.8
Mg
57.6
41.1
139.8
41.1
156.3
82.3
238.6
123.4
181.0
98.7
197.4
82.3
87.7
156.3
151.0
320.8
296.1
320.8
41.1
238.6
156.3
41.1
238.6
238.6
361.9
238.6
389.9
904.9
436.0
378.4
238.6
361.9
Na
870.0
169.7
204.5
8.7
208.8
408.9
130.5
356.7
400.2
826.5
391.5
95.7
695.7
30.5
1609.7
130.5
696.0
78.3
609.0
56.6
174.0
565.5
274.1
134.9
522.0
1131.0
30.0
30.5
413.3
169.7
104.4
8917.5
K
155.0
48.6
26.8
5.1
51.1
51.1
0.0
46.0
51.1
61.4
48.6
7.7
86.1
7.7
83.5
41.4
74.2
56.8
61.4
23.5
40.9
63.9
18.4
47.1
25.6
33.8
19.9
7.7
7.7
17.9
44.5
227.6
so4
624.6
124.9
232.0
41.6
177.0
374.8
20.8
208.2
208.2
84.3
229.0
83.3
125.6
41.6
333.0
124.9
87.4
20.8
104.1
104.1
41.6
41.6
333.1
41.6
249.9
333.1
63.5
104.1
62.5
416.4
20.8
541.3
Cl
338.5
28.2
33.9
31.0
28.2
172.1
28.8
143.9
158.0
297.6
172.1
31.0
217.2
19.8
912.0
28.2
56.4
28.2
28.2
0.0
135.4
28.2
0.0
0.0
28.2
0.0
4.2
28.2
42.3
28.2
28.2
7898.8
Sum of
cations
1382.0
498.9
630.6
334.3
655.7
861.7
608.6
805.5
891.8
1236.1
916.9
505.1
1057.5
673.5
2138.6
891.9
1305.8
895.0
1180.6
917.5
850.2
1014.8
1129.9
1268.9
1608.1
2002.2
1369.9
1492.0
1356.0
1863.4
1635.0
10106.0
Ion
balance
4.4
-2.8
-2.4
-34.3
-4.4
-21.6
3.3
-12.1
-3.5
25.6
-6.2
-34.3
7.4
-4.1
8.7
2.1
36.4
10.1
19.4
-2.9
-21.7
4.5
-13.5
15.9
16.9
17.9
-6.9
-5.2
-15.6
-8.1
-0.9
-0.1
-------
Table D-l. (concluded)
083
084
085
086
087
088
089
090
091
092
093
094
095
096
097
098
099
100
101
102
103
104
105
106
107
108
109
Lake
Trail
Unnamed C
Ice Reservoir
Lake Beaver F
Swan
Cache
White N
B Beaver F
Lake Slide
Trout
Mammoth
Blacktail
Buck
Joffe
Tern E
B Slide
Shrimp
Fawn
White S
B Feather
Tern W
Foster
Crevice
B Trumpeter
Floating Island
L Trumpeter
Geode
Alk
1700
1800
1840
1860
2000
2040
2040
2160
2280
2280
2360
2400
2400
2400
2560
2760
2800
2880
2880
3100
3120
3520
4800
5200
8600
10380
21860
Year
1971
1973
1974
1975
1975
1974
1975
1975
1975
1975
1975
1966
1965
1973
1975
1974
1965
1975
1975
1966
1975
1977
1976
1977
1966
1977
1979
Elev
2362
2120
1671
1987
2215
2454
2505
1932
1729
2104
2018
2012
2119
1982
2502
1729
2159
2368
2505
2168
2504
2018
1695
1873
1997
1862
1823
Sum of Ion
pH Ca Mg Na K SO^ Cl cations balance
8.50 High alkalinity lakes. Only partial data set presented.
7.60
9.00
7.25
8.20
8.00
7.80
8.00
7.20
9.00
7.40
8.40
9.00
8.40
9.00
7.50
8.90
7.80
7.75
8.70
7.70
9.00
8.00
8.80
9.45
9.50
10.00
-------
Table D-2. Chemistry data for Yellowstone National Park lakes 1970 and earlier.
CO
Lake
Cascade
Crag
Crescent
Grebe
High
Ice
Wolf
Year
1969
1970
1970
1963
1970
1969
1969
Alk
340
100
270
440
280
110
270
Ca
299.9
39.9
150.2
159.7
289.9
99.8
250.0
Mg
50.2
9.9
29.6
79.8
29.6
50.2
50.2
Na
180.1
10.0
20.0
159.6
60.0
150.1
180.1
K
19.9
21.0
27.1
68.3
45.0
10.0
29.9
so4
129.9
60.6
64.5
50.0
65.2
170.1
170.1
Cl
—
7.1
11.2
14.1
7.1
—
31.0
Ion
balance
—
-69.9
-41.6
-7.5
18.6
—
7.9
-------
50272 -101
REPORT DOCUMENTATION i- REPORT NO.
PAGE FWS/OBS-80/40.17
4. Title and Subtitle
Rocky Mountain Acidification Study
7. Author(s)
Gibson, J. , J. Gall oway, C. Schofield, W. Me Fee, R. J oh nso n
9. Performing Organization Name and Address
_ McCarley? N_ ^
Natural Resources Ecology Laboratory
Colorado State University
Fort Collins, CO 80523
^ D<
12. Sponsoring Organization Name and Address
U.S. Department of the Interior, Fish and Wildlife Service
Division of Biological Services, Eastern Energy and Land Use
Team, Route 3, Box 44, Kearneysville, WV 25430
3. Recipient's Accession No.
5. Report Date
October 1983
6.
8. Performing Organization Rept. No.
10. Project/Task/Work Unit No.
11. Contract(C) or Grant(G) No.
(c, 14-16-0009-81-029
(G)
13. Type of Report & Period Covered
Jinal
14.
15. Supplementary Notes
16. Abstract (Limit: 200 words)
The objectives of this report were to determine the sensitivity of
watersheds characteristic of the Rocky Mountain Region and the relationship of watershed
sensitivity to geology and soils; to evaluate the extent of current acidification and the
potential for increasing acidification with increasing deposition of nitrate and sulfate;
to evaluate the results of the preceding in terms of impacts on fish populations; and to
develop recommendations for assessment of future trends in both changing water chemistry
and impacts on fish populations. Areas selected for study included the Rocky Mountain
National Park and Yellowstone National Park, exemplifying two different geologic types
that are representative of a large portion of the Rocky Mountain region. Rocky Mountain
National Park is primarily underlain by granite and Yellowstone National Park by volcanic
materials. Sensitivity is primarily determined by bedrock geology and varies inversely
with elevation. High-elevation lakes and streams in the central Rocky Mountain region
are very sensitive to acidic deposition. With respect to fish populations there is
currently no evidence of chronic acidification and thus no apparent impact on fisheries.
However, the very low base cation concentration observed in the headwater drainages of
Rocky Mountain National Park suggests extreme sensitivity to acidification. Waters in
volcanic areas such as Yellowstone National Park are generally of high alkalinity and do
not represent potentially sensitive habitats.
17. Document Analysis a. Descriptors
acidification, impacts, fisheries, acid precipitation, geology
b. Identifiers/Open-Ended Terms
acid rain, acidified waters, acid deposition, Rocky Mountains, national parks
i.. COSATI Field/Group
18. Availability Statement
19. Security Class (This Report)
unlimited
___
20. Security Class (This Page)
unclassified
21. No. of Pages
_xi_v_ + 137
22. Price
(See ANSI-Z39.18)
US GOVERNMENT PRINTING OFFICE 1984—777-798 9154 REGION NO
See Instructions on Reverse
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Cnmm«..*-~
-------
"fa Headquarters, Division of Biological
Services, Washington, DC
x Eastern Energy and Land Use Team
Leetown, WV
# National Coastal Ecosystems Team
Slidell. LA
• Western Energy and Land Use Team
Ft, Collins, CO
^ Locations of Regional Offices
REGION 1
Regional Director
U.S. Fish and Wildlife Service
Lloyd Five Hundred Building, Suite 1692
500 N.E. Multnomah Street
Portland, Oregon 97232
REGION 2
Regional Director
U.S. Fish and Wildlife Service
P.O.Box 1306
Albuquerque, New Mexico 87103
REGION 3
Regional Director
U.S. Fish and Wildlife Service
Federal Building, Fort Snelling
Twin Cities, Minnesota 55111
REGION 4
Regional Director
U.S. Fish and Wildlife Service
Richard B. Russell Building
75 Spring Street, S.W.
Atlanta, Georgia 30303
REGION 5
Regional Director
U.S. Fish and Wildlife Service
One Gateway Center
Newton Corner, Massachusetts 02 1 58
REGION 6
Regional Director
U.S. Fish and Wildlife Service
P.O. Box 25486
Denver Federal Center
Denver, Colorado 80225
REGION 7
Regional Director
U.S. Fish and Wildlife Service
1011 E.Tudor Road
Anchorage, Alaska 99503
------- |