United States
                   Environmental Protection
                   Agency
Environmental Monitoring
Systems Laboratory
Las Vegas NV 89114
                   Research and Development
EPA-600/S7-84-088  Jan. 1985
&ERA         Project Summary

                   Monitoring Approaches  for
                   Assessing  Quality  of High
                   Altitude  Lakes:  Colorado  Flat
                   Tops  Wilderness  Area
                   Barry P. Baldigo and John R. Baker
                     Three high altitude lakes were selected
                   and sampled  to develop monitoring
                   approaches for assessing lake sensitivity
                   to acid deposition. Sampling of Ned
                   Wilson, Oyster and Upper Island lakes in
                   the Flat Top Wilderness Area of Colorado
                   was conducted in 1982 and 1983. These
                   lakes are representative of the range of
                   lakes sensitive to acid deposition in the
                   area.
                     Data collected show the three study
                   lakes are  biologically and chemically
                   similar. Available literature  suggests
                   biological  communities of the study
                   lakes are sensitive to acidification, with
                   major  impacts expected as pH drops
                   below  5.5. Lack of specific  acidity
                   sensitivity data  for most species of
                   organisms inhabiting the study lakes
                   precludes  precise predictions  of
                   biological  response to acidification.
                   However, annual  sampling  for
                   community changes  and  indicator
                   species of phytoplankton, zooplankton,
                   and macroinvertebrate populations is
                   recommended. Data on fish population
                   structure  and  maintenance  mecha-
                   nisms  are  needed   before fish
                   community information can be used for
                   monitoring, but metal  concentration
                   data for fish tissue and sediments
                   should be  collected for residue levels.
                   Nineteen physical and chemical water
                   quality  parameters, including eight
                   metals, are recommended for annual
                   scans.
                     This Project Summary was developed
                   by EPA's  Environmental Monitoring
                   Systems Laboratory. Las Vegas, NV. to
                   announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).


Introduction
  This report summarizes results of a
joint U.S.   Environmental Protection
Agency and  U.S. Geological  Survey
sampling effort conducted during 1982
and 1983 on three lakes in the Flat Tops
Wilderness Area of northwestern
Colorado. Sampling was  conducted to
provide  an  assessment of the current
biological and  chemical  conditions of
these index lakes which is essential for
assessing monitoring requirements and
long term designs for these and similar
lakes.  Distributions, abundances and
types of biota resident in these lakes
determine  the  type  of biological
monitoring  program  most suitable  for
sampling frequencies, site selection and
distribution,  and identifying sensitive
communities or community components.
A basic understanding of the physical and
chemical characteristics is necessary for
parameter selection and  determining
sampling  sites, distributions, and
frequencies. Factors such as parameter
responsiveness to acidification, ease of
measurement,  temporal,   spatial, and
vertical variability are important consid-
erations in monitoring designs.
  Located within the boundaries of the
White River National Forest, the Flat Tops
Wilderness  Area of northwestern
Colorado includes numerous lakes, many
higher than  3300 m in elevation.

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Background
  Approximately 370  lakes within the
Flat Tops Wilderness Area have  been
estimated  to   be  very  sensitive  to
acidification. All have alkalinities, either
predicted or measured, less than or equal
to 200 //eq/L CaCO3; some have  been
recorded at 70 peq/L CaC03. The high
sensitivity  of   most  lakes  results
principally from the small amounts of
calcarious  sediments   in  their
watersheds. Basalt caprock  underlies
most lake beds and watersheds of the
higher altitude lakes. Additionally, small
watershed-to-lake  surface area  ratios
reduce the water/soil contact time of
runoff.  Hence,  the small amounts of
CaC03 in sediments have little chance to
dissolve in these runoff waters.
  The  severity  of  acid  precipitation
effects in the Flat Tops could increase due
to expansion of the oil shale industry.
Expansion of synfuels(including oil shale)
production and coal-fired power plants on
the Rocky Mountain western slope
"Energy Belt" may increase hydrogen ion
concentrations in wet and dry deposition
and will undoubtedly, contribute increas-
ing amounts of  SO2 and NO, to the
atmosphere.

Monitoring Requirements
  Unique  sampling  problems  are
encountered  in   wilderness  areas.
Because the Flat Tops are accessible only
by foot or horseback, severe restrictions
are placed on the use of the cumbersome
and/or fragile equipment used in  more
conventional  studies.  Additionally,
sampling is normally restricted to summer
(ice  free)  months due  to  a  heavy
snowpack most of the year. Because
monitoring approaches and techniques
tested in the lakes of the Flat Tops have
helped identify techniques best suited for
these  conditions,  refined  monitoring
strategies  suitable for application in
these  types  of  areas  can  now  be
suggested.

Methods and Materials
  Samples collected  each  year  and
methods  used  in their  collection  are
summarized in Table 1.

Results and  Discussion
  Components of the Flat Tops lakes zoo-
plankton,  phytoplankton  and  fish
communities are subject to alterations as
the pH  of water approaches 5.5, and
certain  macroinvertebrate species  are
known to be sensitive to waters with pH
values of 6.0 to 6.5. Once these levels are
reached disruptions will be expected in
the biotic communities of the study lakes.
Currently, summer daytime pH levels in
all three study lakes are typically above 6.0.

Phytoplankton
  Within-lake differences in phytoplank-
ton assemblages  were apparent in all
lakes.  However, between-station  and
depth related variability were largely
attributable to rare species with dominant
and co-dominant species relatively  uni-
formly distributed throughout each lake.
Discrete samples from the deep site on
Upper Island Lake yielded slightly more
diverse assemblages at 1 m than at 5 and
10m. The majority of taxa collected at the
various strata were present in the  1 m
sample, suggesting that a near surface
sample taken from a stratified lake will
collect most of the more common phyto-
plankton species.
  Annual and seasonal  variability of the
phytoplankton community were high in
all lakes.  Also, bet ween-lake differences
in the composition and  abundance of
phytoplankton  communities  were
apparent  in  samples   collected   on
approximately the same dates. Because
of differences in the succession patterns
of the phytoplankton assemblages in the
various lakes,  and  because  different
assemblages  were  noted in  individual
lakes  during   mid  August  of  two
successive years,  it seems unlikely  that
once-a-year  sampling will provide ade-
quate data to depict long term changes in
phytoplankton assemblages  in  the
various lakes. Differences in succession
patterns need to be further investigated
during the  open  water period.  It is
suggested that near-surface (e.g., 1-1.5
m) quantitative samples be collected and
composited from 3 to 4 sites per lake at
two   week  intervals,  to  examine
succession patterns. In addition, replicate
discrete quantitative samples  should be
taken at three depths (e.g., 1.5, 5 and 10
m) during a period of strong stratification
and again during isothermal conditions to
examine   distribution  throughout  the
water column.

Zooplankton
  Zooplankton species  richness  in the
three Flat Tops study lakes is low and
changes in diversity will probably not be
useful in future monitoring.  However,
permanent  changes  in community
composition (acid  sensitive  and  acid
tolerant species) can be indicative of acid-
ification. Sensitivity to acidification of the
copepod species (Diaptomus spp.), having
distributions restricted  to high altitude
lakes, are not known and their sensitivity
should be determined for possible use in
future monitoring.
  Annual zooplankton differences within
individual  lakes,  based  upon  August
sampling during successive years, were
minor. Differences that were noted were
attributable principally to occurrences of
rare  species.   Because  with-in   lake
variability between sites was also low, it
appears that replicate, depth-integrated
samples collected at a single deep site
during the period of strong stratification
would be adequate to characterize the
zooplankton  communities  of the  study
lakes for purposes of showing differences
between lakes and over time.
  Seasonal  variability and succession
patterns  of zooplankton  communities
were  not   addressed in  this  study,
consequently  no  conclusions   or
recommendations can be made regarding
optimal sampling frequencies or seasons.
Sampling at a  single  deep site at two-
week intervals during the open water
period would provide considerable infor-
mation  on   succession  patterns   of
zooplankton  assemblages. Knowledge of
these patterns would aid in the design of
long-term  monitoring programs  with
respect to required sampling frequencies
and  optimal  sampling  periods  (e.g.,
stratified vs. non-stratified lake condi-
tions).

Macroinvertebrates
  Different  macroinvertebrate  commu-
nities occupied the littoral (shoreline) and
profundal (deep) zones of the three Flat
Tops  lakes.  Qualitative sampling in the
littoral zone  yielded more diverse assem-
blages than were found in quantitative
grab samples from the profundal zone. To
adequately   characterize  macroinverte-
brate communities of individual lakes it is
essential that  both  zones be sampled.
Because  the acidification  sensitivity  of
individual taxa  is not  well known, it is
important to examine entire assemblages
occupying various habitats using changes
in indices of community structure, (e.g.,
diversity, richness,  density) when  pos-
sible.
  Annual  differences  in  various  study
lake's macroinvertebrate  communities
indices were significant, hence frequent
(yearly) sampling may be necessary  to
access annual variability. Because recruit-
ment and emergence  affect "seasonal"
species population  size, temporal vari-
ation during ice free periods should  be
determined  at least once. Except for one
shallow Ned Wilson Lake site, bet wee n-
site macroinvertebrate community indices

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Table 1.    Summary of Sample Sites. Dates, Numbers and Types Collected During 1982 and 1983 Flat Tops Lakes Surveys. Field Measureable
           Parameters, e.g.. Temperature, pH, D.O.. Conductivity, etc.. are not Included in this Summary
Lake
Ned Wilson










Oyster




Upper Island



Ned Wilson
















Oyster



Upper Island










Ned Wilson
Sites
1.2.3.4
"
"
shoreline
"
2
2
2
2
shoreline
spring
1.2
"
"
shoreline
2
1.2.3.4
"
4
shoreline
1.2.3.4
2
2
2
2
2
2
2
2
2
1.2,3,4
M
shoreline
"
"
"
"
1.2
"
"
shoreline
1.2.3.4
4
4
4
4
4
1.2.3,4
4
4
shoreline
shoreline
1.2.3.4
Sample
Phytoplankton
Zooplankton
Macroin vertebrates
Fish-metal content
Fish-stomach contents
Phytoplankton
"
"
"
Macroinvertebrates
"
Phytoplankton
Zooplankton
Macroinvertebrates
11
Sediments-metal content
Phytoplankton
Zooplankton
Macroinvertebrates
Macroinvertebrates
Phytoplankton
"
"
"
"
a
"
"
'•
"
Zooplankton
Macroinvertebrates
"
"
••
"
Fish-metal content
Phytoplankton
Zooplankton
Macroinvertebrates
"
Phytoplankton
"
"
"
"
"
Zooplankton
Macroinvertebrates
"
a
Fish-metal content
Alkalinity, Color
Type
D.I.G.1
V.T.4
Ekman


Grab"
"
••
"
Qual*
"
D.I.G.
V.T.
Ekman
Qual

D.I.G.
V.T.
Ekman
Qual
D.I.G.
Grab
"
"
a
"
"
"
a
••
V.T.
Ekman
Qual
H.D.7
B.K.*
10-R.'

D.I.G.
V.T.
Ekman
Qual
D.I.G.
Grab
tt
Grab, 1Om"
Grab. 5m
Grab. 1m
V.T.
Ekman
Qual
10-R

D.I.G.
Reps.
23
1
3
6
1
1
1
1
1
5
1
2
1
3
3
1
2
1
3
3
1
1
1
2
2
2
2
2
2
2
3
3
4
4
4
3010
5
2
3
3
3
2
2
2
2
2
2
3
3
3
3010
2
1 pe,
Total No.
8
4
12
6
1
1
1
1
1
5
1
4
2
6
3
1
8
4
3
3
4
1
1
2
2
2
2
2
2
2
12
12
4
4
4
30
5
4
6
6
3
8
2
2
2
2
2
12
3
3
30
2
'site
Date1
08/17/82
"
~
09/01/82
08/17/82
07/21/82
08/04/82
09/10/82
10/03/82
08/17/82
08/18/82
08/18/82
ft
*
//
M
n
08/20/82
••
it
••
07/25/83
04/14/83
06/28/83
07/20/83
07/29/83
08/12/83
08/17/83
08/30/83
09/10/83
09/28/83
08/25/83
n
n
ft
n
••
ft
08/24/83
tt
tt
n
O8/27/83
08/10/83
08/24/83
08/27/83
tt
"
tt
tt
tt
ft
tt
08/25/83

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Table  1.   (Continued)
Lake
                        Sites
                     Sample
Type
Reps.
                                                                                            Total No.
                                                                                     Date'
Oyster
Upper Island
  1.2        Total P. Nitrate
1,2,3.4       Nitrite. Ammonia.
            TOO, DOC, Surfate,
            Chloride. Fluoride,
            and Total Metals
                                                              D.I.G.
                         3 per site
                      08/24-27/83
 * Actual day may vary by ± one day.
 "Depth Integrated Grab (Van Dorn) sample.
 3Only one replicate phytoplankton sample per site processed in 1982.
 ^Vertical Tow-Standard Wisconsin Plankton Net; bottom to surface.
 sGrab sample at surface.
 'Qualitative Triangular Dip Net (570(im mesh).
 7Hester-Dendy Plate sampler.
 ^Rectangular Basket with rocks.
 910-rock method.
'"Three replicates analyzed,
1 'Discrete Depth sample.
were not significantly different in  any
lake during either year, hence replicate
samples from one deep  site  should
adequately assess the status of prof undal
invertebrate assemblages in these index
lakes during future monitoring.

Salamanders
  Salamanders in Oyster Lake may serve
as useful monitors because they breed in
pools  subject  to influx of  snowmelt
pollutants.  Sensitivity  of various
Ambystoma tigrinum life stages to acidi-
fication are not known, and  should be
determined for use in future monitoring.
Increased acidification  of  Oyster Lake
could result in decreased population or
loss of salamanders. A. tigrinum sen-
sitivity to acidic conditions  should be
determined  for  possible use in future
monitoring.
  Limited sampling and visual observa-
tions revealed the presence of salmonids
in two of the three study lakes. It is not
known whether trout in these lakes are
reproducing naturally  or whether they
are  the result of  repeated  stocking.
Because  early  life stages  are more
sensitive to acidification and  associated
effects (e.g.,  metal  releases) than are
adults, artificially maintained populations
would not be good monitors of acidifica-
tion induced changes. On the other hand,
naturally reproducing populations would
likely be  affected by any  reduction in
ambient pH  levels,  or by  additional
releases  or  mobilization  of  metals
because of the high vulnerability of egg
and larvae stages. Determination of fish
                 population  structure and maintenance
                 mechanisms  is an initial essential step
                 toward incorporation of fish surveys into
                 a monitoring  program.
                   Metal concentrations  in whole
                 homogenized brook trout were low in Ned
                 Wilson Lake during both 1982 and 1983.
                 Two  specimens  of  cutthroat  trout
                 collected from Upper Island Lake during
                 1983 yielded  levels of copper, nickel and
                 zinc an order of magnitude higher than
                 were found in Ned Wilson  Lake brook
                 trout. Concentrations in gills of fish from
                 both lakes were much  lower than  in
                 whole  fish. Because these  metals are
                 biocumulative, it is recommended that
                 analyses  of   whole  fish  (e.g.  three
                 specimens/lake)  be  conducted   once
                 annually to monitor tissue residue levels.

                 Metals in Sediments
                   Concentrations  of  metals within
                 sediments  of the study lakes are within
                 expected ranges for unimpacted Western
                 U.S. water bodies. Because  changes in
                 sediment metal chemistry may occur as a
                 result  of  increased  metal  inputs  or
                 changes in  water chemistry,  annual
                 collection  and  analysis of  sediment
                 samples for metal content should be an
                 integral  component  of  a  long-term
                 monitoring program.

                 Water Quality
                   Physical  and  chemical water quality
                 data for the study lakes were similar to
                 those  reported for  other lakes in this
                 region of  Colorado.  Mean  alkalinity
                 values were less than 100//eq/l in two of
                    the lakes, but exceeded 200 /ueq/l in one
                    lake. The pH levels in  the low alkalinity
                    lakes were 6.3 to 6.8, whereas pH in the
                    third  lake exceeded 8.0.  Conductivity
                    levels   were  typically  low  (64-112)
                    /umhos/cm)  reflecting  the   low
                    concentration of dissolved substances in
                    the water. Concentrations of total metals
                    were also low,  with  aluminum, iron,
                    calcium and magnesium being the most
                    abundant elements. Toxic metals were
                    not measured in concentrations that pose
                    any hazard to aquatic life.
                       Key  water  quality  parameters
                    recommended for monitoring include the
                    nitrogen species (NO2, NO3, and  NH3),
                    sulfates, pH, alkalinity, conductivity, total
                    phosphorus,  temperature,  dissolved
                    oxygen,  total  and  dissolved  organic
                    carbon  and dissolved  inorganic carbon.
                    Annual scans of total recoverable and
                    dissolved aluminum, copper, lead, nickel,
                    iron, silver, calcium  and  magnesium
                    should also be included.

                    Conclusions
                       Lack  of acid sensitivity data for most
                    species of organisms inhabiting the study
                    lakes preclude concise predictions of bio-
                    logical response to acidification. Testing
                    for acid sensitivity of certain potentially
                     indicator species, assemblages and whole
                     lake  ecosystems may help formulate
                    accurate predictions of acid deposition
                    effects on biota of high altitude lakes.

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     Barry P. Baldigo and John R. Baker are with Lockheed Engineering & Management
       Services Co.. Inc., Las Vegas. NV 89109.
     Wesley L. Kinney is the EPA Project Officer (see below).
     The complete report, entitled "Monitoring Approaches for Assessing Quality of
       High Altitude Lakes: Colorado Flat Tops Wilderness Area." (Order No. PB 85-
       117 232; Cost: $ 19.00, subject to change) will be available only from:
            National Technical Information Service
            5285 Port Royal Road
            Springfield, VA  22161
            Telephone: 703-487-4650
     The EPA Project Officer  can be contacted at:
            Environmental Monitoring Systems Laboratory
            U.S. Environmental Protection Agency
            P.O. Box 15027
            Las Vegas. NV 89114
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
     BULK RATE
POSTAGE & FEES PAID
        EPA
  PERMIT No. G-35
Official Business
Penalty for Private Use $300

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