Ecological Research Series
  PHOSPHATE  REDUCTION AND  RESPONSE OF
PLANKTON POPULATIONS IN  KOOTENAY LAKE

                               Environmental Research Laboratory
                              Office of Research and Development
                              U.S. Environmental Protection Agency
                                     Corvallis, Oregon  97330

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                 RESEARCH REPORTING SERIES

 Research reports of the Office of Research and Development, U.S. Environmental
 Protection  Agency, have been grouped into five series. These five  broad
 categories were established to facilitate further development and application of
 environmental technology. Elimination of traditional grouping was consciously
 planned to foster technology transfer and a maximum interface in related fields.
 The five series are:

     1.    Environmental Health Effects Research
     2.    Environmental Protection Technology
     3.    Ecological Research
     4.    Environmental Monitoring
     5.    Socioeconomic Environmental Studies

 This report has been assigned to the ECOLOGICAL RESEARCH series. This series
 describes  research on the effects  of pollution on humans, plant and animal
 species, and materials.  Problems are assessed for their long- and short-term
 influences. Investigations include formation, transport, and pathway studies to
 determine the fate of pollutants and their effects. This work provides the technical
 basis for setting standards to minimize undesirable changes in living organisms
 in the  aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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                                              EPA-600/3-76-063
                                              May 1976
PHOSPHATE REDUCTION AND RESPONSE OF PLANKTON

        POPULATIONS IN KOOTENAY LAKE
                     by
             Richard A. Parker
        Washington State University
         Pullman, Washington  99163
           Grant Number R-800430
              Project Officer

             D. Phillips Larsen
Corvallis Environmental Research Laboratory
          Corvallis, Oregon  97330
   U. S. ENVIRONMENTAL PROTECTION AGENCY
     OFFICE OF RESEARCH AND DEVELOPMENT
CORVALLIS ENVIRONMENTAL RESEARCH LABORATORY
          CORVALLIS,  OREGON  97330

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                                DISCLAIMER
This report has been reviewed by the Corvallis Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for
publication.  Approval does not signify that the contents necessarily
reflect the views and policies of the U.S. Environmental Protection
Agency, nor does mention of trade names or commercial products
constitute endorsement or recommendation for use.
                                    ii

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                                  ABSTRACT
     The purpose of this research project was to determine the effects
of reducing by 90 percent the soluble inorganic phosphate input to
Kootenay Lake, British Columbia, Canada, a significant link in the
Columbia River system governed by United States-Canadian treaty.
Measurements on temperature, transparency, inorganic and organic
phosphate, nitrate, ammonium, chlorophyll j., copepods, and cladocerans
were made during 1971-75, and compared with observations made for three
years prior to phosphate reduction in 1969.  Only a slight decrease in
chlorophyll occurred, although there were important changes in species
composition.  Total zooplankton levels were not-affected, however one
genus (Daphnia) has virtually disappeared.  Data indicate that primary
production in the lake was nitrogen limited prior to 1969, phosphate
limited two years later.   These changes may also be related to the
completion in 1972 of Libby Dam in Montana, upstream from the lake on
the Kootenay River.  An overview of the results is reported, with
detailed accomplishments reported in Parker 1»2>3»4»5>6 incorporating
the unpublished work of J. E. Cloern, J. R. Davis, J. R, Hargis, and
K. G. Taylor.

     This report was submitted in fulfillment of grant number R800430
by Washington State University under the partial sponsorship of the
Environmental Protection Agency.  Work was completed as of July 1975.
                                  iti

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                                CONTENTS







                                                             Page




Abstract                                                      ill




List of Figures                                                vi




List of Tables                                                vii




Sections




  I  Introduction                                               1




 II  Conclusions                                                3




III  Recommendations                                            4




 IV  Field Observations and Laboratory Analyses                 5




  V  Simulation Model                                          32




 VI  References                                                49




VII  Appendix                                                  53

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                                FIGURES
No.
 1        Sampling stations on Kootenay Lake                      6
 2        Flow of the Kootenay River at Station 1                 8
 3        Mean temperatures at Stations 1-5                       9
 4        Extinction coefficients                                10
 5        Soluble inorganic phosphate concentrations             12
 6        Soluble organic phosphate concentrations               13
 7        Particulate phosphate concentrations                   14
 8        Nitrate concentrations                                 16
 9        Ammonium concentrations                                17
10        Phytoplankton levels                                   18
11        Copepod levels                                         21
12        Cladoceran levels                                      22
13        Total zooplankton densities at Station 2               24
14        Gravid zooplankton densities at Station 2              25
15        Total zooplankton densities at Station 3               26
16        Gravid zooplankton densities at Station 3              27
17        Total zooplankton densities at Station 4               28
18        Gravid zooplankton densities at Station 4              29
19        Total zooplankton densities at Station 5               30
20        Gravid zooplankton densities at Station 5              31
21        Simulated soluble inorganic phosphate concentrations   37
22        Simulated nitrate concentrations                       39
23        Simulated ammonium concentrations                      41
24        Simulated phytoplankton levels                         42
25        Simulated copepod levels                               43
26        Simulated cladoceran levels                            44
27        Velocity and volume flow at Station 1                  45
28        Velocity at four depths at Station 2                   47
29        Mean northerly velocity at Station 2 along             48
          north-south axis of lake, and flow at Station 1
                                   vi

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                                 TABLES
No.

1         Drainage characteristics and nutrient loadings          2
          for Kootenay Lake

2         Algal genera identified from Kootenay Lake for         20
          1965-66 by Pillion e_t al. (unpublished) and for
          1973-75 by Cloern and Prescott (unpublished)

3         Variables used in the nutrient-plankton model of       34
          the mixed layer in Kootenay Lake

4         The model system                                       36

5         Constants used in the simulation model                 38
                                 vii

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                               SECTION  I

                              INTRODUCTION

      The  effects  of  an  Increase  in  the  nutrient budget  on  lakes
have  been veil  documented  in  several cases  (see for example Hasler7,
Edmondson et  al.  , Edmondson  , Beeton   *    , Verduin  ).   There
have  been fewer reports of the response by  an enriched  lake after
reduction in  the  nutrient  income (Edmondson13>  14> Ahlgren15, Malueg
at _al.16).  Kootenay Lake,  a  large, generally oligotrophic lake
in southeastern British Columbia, Canada, received significant
quantities  of inorganic phosphate via the Kootenay River from 1953
until 1969.   This material originated primarily from the activities
of a  fertilizer plant located on a  tributary of the Kootenay River
near  Kimberley,  British  Columbia.  Early in  1969 there was  a large
reduction (80-90%) in the  amount of phosphate being put into the
river and thus  into  the  lake.
      Prior  to phosphate  reduction,  Taylor17 and Parker1 conducted a
limnological  study from  1966  until  1969, emphasizing nutrient levels
and plankton  densities.  About the  same time, Fillion (unpublished)
focused attention on the phytoplankton  composition.  His samples
have  subsequently been examined by Northcote et al. (unpublished)
at the University of British  Columbia.  ZyblutT8~eviewed  long-term
changes in  the  zooplankton population of Kootenay Lake, and North-
cote1^ provided a historical  account of the salmonid fishery as it
related to human  activities and nutrient loading.  Further study
was begun in  1971 and continued  through May 1975.  Results from the
second period will be compared with those given by Taylor17, focusing
largely on  changes in nutrient concentrations and plankton populations,
It also should be pointed  out that  changes caused by reduced phosphate
income have been  compounded by completion of Libby Dam, located
several hundred kilometers upstream on  the Kootenay River in Montana.
Shortly after leaving the Lake, the Kootenay River joins the Columbia
River, providing  about 30 percent of the total low flow at that point.
The general drainage characteristics of Kootenay Lake, as well as
nutrient loading before and after 1969, are sunmarized in Table 1.

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           Table 1.  DRAINAGE CHARACTERISTICS AND NUTRIENT
                      LOADINGS FOR KOOTENAY LAKE
Drainage Characteristics
                       2
     Drainage Basin (km ) 2                        45,669
     Lake Surface Area (km )                          417
     Annual Inflow £n )                            26 x 10
     Lake Volume (m )                              40 x 10
     Retention Time (days)                            566
     Lake Mean Depth (m)                               96
Nutrient Loadings
                            2
     Nitrate - Nitrogen (g/m /yr)
       1966-69                                          0.45
       1971-74               2                          0.48
     Ammonium - Nitrogen (g/m /yr)
       1967-69                                          0.25
       1971-74                 2                        0.18
     Phophate - Phosphorus (g/m /yr)
       1966-69                                          0.68
       1971-74                                          0.051

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                                SECTION  II

                              CONCLUSIONS

Seasonal  flow patterns of the Kootenay  River have been altered con-
siderably by the completion of  Libby Dam in 1972.  The peak values
during  the spring run-off period in late May and early June have
been reduced approximately 50%, with the balance of the flow being
distributed over the summer period.  Temperatures in the lake are
somewhat  lower than before the  construction of the dam, and the
transparency of the lake has been increased by a factor of two
during  late spring and early summer, coincident with lower volume
flows.

Soluble inorganic phosphate entering the lake has decreased approx-
imately 90% since 1969.  There  has also been a concurrent decrease
in the  soluble organic phosphate fraction as well as in the parti-
culate  phosphate.  The soluble  organic  fraction has, however, not
decreased as much as the inorganic fraction.  Furthermore, the
decrease  in the particulate fraction can be attributed largely to
a decrease in silt load brought about by reduced flows of the
Kootenay River.  Nitrate and ammonium concentrations have changed
little  since 1969, although reductions during the summer period due
to algal growth no longer appear to be limiting to the phytoplankton
populations.   Rather phosphate has become the nutrient of prime
consideration.

Chlorophyll a. levels in Kootenay Lake have been reduced 10-15% as
a result of reduced phosphate input and somewhat lower temperatures.
There has been a change in the species composition of the phyto-
plankton, with diatoms playing an increaalngly important role relative
to blue green algae.  Daphnia has been virtually eliminated from
Kootenay Lake for reasons that are unclear.  Preferential feeding
by landlocked sockeye salmon in a more transparent lake could be
responsible.   This would of course require that Diaphanosoma not
be preyed upon heavily since this genus has become the dominant
cladoceran in the lake.  Larger copepod populations could be brought
about by reduced grazing pressure by Daphnia on important food items
like Cyclotella and Cryptomonas.

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                                 SECTION III

                               RECOMMENDATIONS

     Although phosphate input into Kootenay Lake has been decreased
from 0.68 to 0.05 g/m /year, attempts to predict the consequences
on plankton populations have only been partially successful.  The
differential equations used to simulate the system suffer from lack
of  an adequate hydrodynamic component, as well as reliable estimates
of essential parameters.  If the model developed for this lake is to
be applied further, or to other lakes, inclusion of a well-defined
hydrodynamic sub-model is recommended.  In addition, rate constants
for phytoplankton populations should be measured in the field, in-
cluding dependence on light intensity, temperature, and nutrient
concentrations.  Other types of mathematical models (e.g. multi-
variate regression) should also be investigated to improve prediction
accuracy needed for sound management.

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                                SECTION IV

                FIELD OBSERVATIONS AND LABORATORY ANALYSES

 METHODS

 Sampling stations on Kootenay Lake were the same for 1971-74 as those
 used by Taylor17, with the exception that Station 3 was discontinued in
 1973 (Figure 1).  Velocity of river input was measured during 1974-75
 at Station 1 with an Ott current meter at 1 m, and at Station 2 by
 means of drogues.  Temperature and light penetration were measured by
 Whitney underwater instruments.   Readings were taken at 1-m intervals
 from the surface to 10 m at Stations 2-5, and to 5 m at Station 1.

 Zooplankton samples were collected at Stations 2-5 using a Clarke-
 Bumpus sampler with a number 10  nylon net towed at approximately 3
 km.p.h.   Two samples were collected at each station and each of three
 depths (1,  5,  10 m).  The samples were preserved in formalin and
 counted subsequently in the laboratory.   Five 1-ml subsamples of a
 known dilution of the original sample were removed by piston pipette
 and counted on Sedgewick-Rafter  cell.   The density of a given zooplankton
 species  was then calculated as follows:

    Number/liter = total no.  in subsamples x     vol.  of dilution
                              5              4 x no.  of revolutions   ^  '

 Water samples  were collected at  each station by Kemmerer bottle.   At
 Station  1 two  samples were  taken at 1  m,  and at Stations 2-5 two samples
 were  collected at each  of the three depths.   Two subsamples  of known
 volume  (300-500 ml)  from each original sample were filtered  using a
 0.45n membrane filter  (Gelman, 47 mm dia.).   One filter was  analyzed
 for particulate phosphate,  and one analyzed  for total chlorophyll a..

 The chlorophyll a. concentrations  were  measured by soaking  the  filter in
 10 ml of  100%  methanol  for  3-4 hours,  then reading the optical density
 at 660 nm with a  1 cm path  length.   To convert the optical density to
 chlorophyll a.  concentration  in yg  /liter, the optical density was
 multiplied  by  13.9  x vol. of  water filtered  x vol. of solvent  used
 (10), as  suggested by Tailing and Driver20.

 The phosphate  concentration was measured  using the method of Strickland
 and Parsons21.  Nitrate was analyzed using the phenoldisulfonic acid
 method of APHA, AWWA, and WPCF22;  ammonia determinations were  made
 using the method  of  Solorzano23.

 Samples ordinarily were collected weekly  during  the summer, biweekly
 in the spring  and fall, and monthly in the winter.  Mean values over 10
meters will be used as the basis  for subsequent discussions of all
variables considered.

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                                                        N
 0       10      20      30  km
Figure 1.   Sampling  locations on Kootenay Lake




                                 6

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 PHYSICAL CHARACTEBISriCS

 River Flow

 The  seasonal  pattern of  flow of  the  Kootenay River was  altered  con-
 siderably following  the  completion of Libby  Dam in 1972 (Figure 2).
 During 1966-1969,  peak flow  occurred early in June and  was  approxi-
 mately two million liters  per second.   In 1972 the peak was approximately
 1.6  million liters per second, less  than 0.5 million liters per second
 in 1973 and about  1.2 million liters per second in 1974.  Attempts to
 disburse accumulated water from  the  reservoir behind.Libby  Dam  over a
 longer period (and more  gradually) were moderately successful.

 This new flow pattern has  had a  considerable effect  on  the  temperature
 regime of the lake,  as well  as on the transparency of the water.
 Nevertheless  the water flows  northward  along the eastern shore  of the
 lake from the point  of entrance  of the  river at the  south end.   In fact,
 this water may travel all  of  the way to the  north end of the lake, where
 it mingles with water entering in the Duncan and Lardeau Rivers, before
 moving southward and out through the west arm.

 Tempejrature
Water is released from behind Libby Dam at various depths below the
surface of the impoundment in order to maintain acceptable temperatures
in the Kootenay River.  The fundamental seasonal pattern has not been
altered in Kootenay Lake, although there has been a small decrease in
mean values  (Figure 3).  Recall that Station 1 is located at the point
where the Kootenay River enters the lake, and that Station 2 through 5
are distributed over the south half of the lake.

Transparency
Figure 4 illustrates well the effect of changing the seasonal flow
pattern on the transparency of water in and entering Kootenay Lake.
The suspended silt load in the river (Station 1) has been reduced
markedly by lowering peak flows.  This has had a pronounced effect on
the extinction coefficients for the upper 10 meters as is clearly
shown in Figure 4.  This reduction in turn has altered the seasonal
growth pattern of the phytoplankton.  Prior to 1972, Kootenay Lake
typically had a spring bloom followed by substantial reduction during
June and another bloom in August and September.  Since 1972, phyto-
plankton levels in the lake have been more evenly distributed through-
out the growing period.  Extinction coefficients in the lake (on a per

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          2.H
      S   1.8
      v,
C30
          0.6
                 1966        1967        1968       1969
1970
YERR
1971        1972        1973        1974
                                     Figure 2.   Flow of the  Kootenay River at Station 1.

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;o o

i*
3; -i
-o
ro
O
 .
3
a
  oo
u
CO
UJ

I
8
            15
             15
            15
     15




      5


      D
                STfi 2J
                STfl 3-
                SIR
         STfl 5
                   1966
                       1967
                                                                  _^
1968
1969
                                                                 1970

                                                                 YEflR
                                                                     1971
1973
1973
1974
                                          Figure  3.    Mean  temperatures at Stations 1-5.

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     SIR 1
3.0

1.0


3.0

1.0


3.0

1.0


3.0

1.0


3.0

1.0
  0
SIR 2
STfl 3
STfl
STfl 5
       1966
              1967
                              1968
1969
                                                 1970
                                                 YEflfi
1971
                                                                             1972
                                              1973
19714
                                    Figure  4.    Extinction coefficients.

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 meter basis)  frequently reached 2.0 in June;  since 1972 values rarely,
 if ever, exceed 1.0.   This means,  of course,  that the depth to which
 one percent of the surface light is transmitted during the most
 turbid periods has been increased  from about  two meters to over four
 meters.

 NUTRIENTS

 Phosphorus
 Prior  to  1969  the amount  of  inorganic  phosphorus  entering Kootenay
 Lake at Station 1 ordinarily exceeded  a  concentration of  12 micromoles
 per liter (yM/1)  during the  winter months.   Since 1969, concentrations
 in entering  river water have not exceeded 2  yM/1  (Figure  5).  Although
 concentrations  were  obviously low during the winter months, maximal
 daily  inputs occurred  during periods of  peak flow.  For example, about
 15 metric tons  entered the lake on 30  May 1966.   Following input
 reduction, a maximum value of 0.75 metric tons entered on 20 May 1972.
 Average entrance  over  the year has been  reduced approximately 10 fold,
 and mean  values in the lake  have been  reduced from approximately 3
 yM/1 to 0.3  yM/1.  The amount of soluble organic  phosphate is shown
 in Figure 6.  This quantity  does not appear  to change significantly
 during the year,  although there has surely been a reduction from
 about  1 yM/1 prior to  1969 to about 0.2  yM/1 since.   Note that the
 inorganic phosphate  pool  in  the lake is  reduced during the summer
 period of peak  algal growth,  particularly during  the  period of 1971-
 1974.  Prior to 1969,  the only significant summer depressions occurred
 in 1966 and  1967.  Particulate phosphate (Figure  7) is composed of
 phosphate adsorbed on  silt particles as  well as phosphate incorporated
 in living organisms.   A review of the  seasonal distribution for this
 variable  indicates that the highest levels are coincident with peak
 river  flow,  thereby  suggesting that much of  the particulate phosphate
 is in  fact adsorbed  material.  Unfortunately no attempt was made to
 distinguish between  particulate phosphate in living organisms from
 that adsorbed to silt  particles and, consequently, one cannot use
 the seasonal distributions as  indicative of plankton  population
 fluctuations.

Nitrogen
The highest nitrate concentrations in the Kootenay River occur
during winter and spring.  These high levels are reflected in
values measured at Station 2-5.  As with phosphate, maximum total

                                    11

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              STfl  1
          10

           5



          10
STR 2
              STR 3
          10
ro
              STfl 4
          10
              STfl 5
           10
           O1—
                 1966        1967       1968       1969
                                                1970
                                                YEflR
1971        1972        1973        1974
                                   Figure 5.    Soluble inorganic  phosphate concentrations.

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    10




     5









    10




     5
y    10
o
10




 5









10




 5




 0
        STP 1
   STfl 2
         STfl 3
         STfl 14
         STfl 5
            1966
                  1967
                                          -t-M-fc.
1968
1969
1970


YEflR
1971
1972
1973
1974
                               Figure 6.    Soluble organic phosphate  concentrations,

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HO

20


40

20


40

20


40

20
    SIR 1
20

 0
SIR 2
SIR 3
SIR
    SIR 5
                                                 _L
1966
1967
                         1968
                                         1969
1970
YEPR
1971
1972
1973
1974
                            Figure  7.    Participate phosphate concentrations.

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 daily Input  coincides with  periods  of peak  river  flow.  During  1966
 and  1967 when inorganic  phosphate levels were  somewhat depressed,
 nitrate concentrations were reduced to near zero, indicating  that
 nitrate was  in fact  limiting the growth of  phytoplankton prior  to
 1969 (Figure 8).   On the other hand, during the period 1971-74,
 nitrate was  never  reduced to zero during the year, whereas  inorganic
 phosphate  frequently could  not be detected  during the same  period,
 Kootenay Lake probably became phosphate limited in terms of primary
 production (Chu2\ Goldberg et_ al.25, Fogg26,  Lackey27, Thomas28).
 One  should also look to  ammonium concentrations (Figure 9)  since algal
 cells may  take up  ammonium  preferentially over nitrate for  at least
 some species (Eppley29).  An examination of the data shows  that in
 1967 ammonium levels reached zero at times  when nitrate was still
 present.   During 1968, nitrate never reached low  levels whereas
 ammonium frequently  was  depressed.  The same can be said for  1969.
 During 1971-74 ammonium  was reduced during  the summer months  but
 was  always measurable.

 BIOLOGICAL POPULATIONS

 Phvtoplankton
Chlorophyll a. readings have been converted to milligrams per liter
dry weight of algae assuming a one-half % concentration of chlorophyll
based on series of measurements made during the month of May.  This
proportion undoubtedly does not remain constant throughout the year,
however conversion to dry weight facilitates comparison with similar
quantities for zooplankton.  There has been a reduction in the number
of major phytoplankton peaks since 1969 (Figure 10), but the annual
means have decreased only about W%.  Figures for 1971 and 1972 sug-
gest that the phytoplankton levels remain reasonably high through-
out the summer, although in 1973 there were distinct peaks in the
spring and late summer at all stations.  Since there was no distinct
period of peak flow or abnormal temperature patterns in 1973, one must
look to nutrients and zooplankton for the cause.  Here phosphate was
essentially zero in midsummer (between peaks), and ammonium levels
remained low.  Nitrate, on the other hand, seemed to mirror the
phytoplankton peaks.  This observation suggests that the phytoplankton
species present had taken up most of the ammonium and were required
to rely on nitrate as a prime source of nitrogen for growth.   Since
the nitrate levels did not in fact go to zero, one is forced to
conclude that phosphate ultimately limited the growth and that perhaps
temperature changes the uptake kinetics in such a way that two peaks
were produced.  One cannot avoid considering a further possibility,
that is, grazing pressure brought about by a massive Increase in the
cladoceran population.

                                   15

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ID
LU
d
C
oc
           1966
                                                                                                    1974
                                       Figure 8.    Nitrate concentrations.

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        STfl 1
i
g
10

 5




10

 5




10

 5




10
        STfl 2
         STfl 3
         STfl
         STfl 5
     10
           1966        1967        1968       1969
                                                    1970
                                                    YEflR
1971        1972
1973       1974
                                        Figure  9.    Ammonium  concentrations.

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<
           1966
1974
                                       Figure 10.    Phytoplankton levels.

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Little  detail is available on algal composition in Kootenay Lake.
During  1965-66, D. Pillion made extensive collections at the lake;
however, he  did not identify many of the species present in his
samples.   Subsequent work by G. Ennis, also from the University of
British Columbia (unpublished), yielded a list of species present
in the  lake  at that time.  This effort was followed in 1973-75 by
the unpublished results of Cloern and Prescott.  Since the material
collected  in 1965-66 was not examined by Cloern and Prescott, nor
was the material collected by Cloern examined by those reviewing
the 1965-66  samples, only generic comparisons seem warranted
(Table  2).   Unfortunately, specific population densities are not
available  for further comparison.  Lately, among the larger forms,
Aaterionella is dominant during May and June, followed by Anabaena.
Phormidium.  and Fragilaria during July, August, and September.  Of
those genera important in the diet of zooplankton, Cyclotella and
Cryptomonas  are prevalent from May through August.  Of significance
here is the  fact the Anabaena did not reach bloom proportions in
1973-75, as  it did traditionally each August during 66-69.  It should
also be pointed out that Oscillatoria was not identified for 1973-
75, as  it had been for 1965-66.   Furthermore Stephanodiscus did
not appear in 1973-75 as it had earlier.  Considerable care must
be taken in  evaluating the generic lists for the two periods,
since the outflow of Duck Lake at the south end of Kootenay Lake
empties into the Kootenay River and contributes algal species that
may not be typical open water forms.  For example, Chiamydomonas»
Eudorina, Pandorina, and Volvox were identified in Kootenay Lake,
but should not be considered typical of the Kootenay Lake plankton.

Zooplankton
The observed copepod and cladoceran quantities in milligrams
per liter were calculated by multiplying numerical densities
by 2.5 and 3*5 micrograms per individual, respectively.  As
with chlorophyll, these values do not remain constant, part-
icularly during periods of peak reproductive activity.  The
total copepod population tended to peak during late summer
and early fall, although they were represented in the lake
throughout the year (Figure 11).  The cladocerans, too, peaked
in late summer; however, they were virtually absent from the
lake during the balance of the year (Figure 12).
                                   19

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      Table 2.  Algal genera identified from Kootenay Lake for 1965-66 by Fillion et^ al (unpublished)  and
                for 1973-75 by Cloern and Prescott (unpublished)
                               1965-66
                                     1973-75
[O
o
Cyanophyta
   Anabaena
   Microcystis
   Merismopedia
   Oscillatoria
   Phormidium

Cryptophyta
   Chroomonas
   Cryptomonas
Pyrrophyta
   Ceratium
   Gymnodinium
   Peridinium
   Peridinlopsis
Chrysophyta
   Dinobryon
   Mallomonas
Chlorophyta
   Ankistrodesmus
   Botryococcus
   Chlamydomonas
   Cladophora
   Cosmarium
   Crucigenia
   Dictyosphaerium
   Dispora
   ElakatothrJbc
   Eudorina
   Gemellicystis
   Kirchneriella
                                         1965-66
                                                                                                   1973-75
                                  X
                                  X


                                  X
                                  X
                                  X
                                  X

                                  X

                                  X
                                  X
                                  X
                                  X

                                  X
                                  X

                                  X
                                  X
X
X
X

X


X
X


X
X
X
X


X
X
   Lagerlieimia
   Oocystis
   Pandorina
   Scenedesmus
   Staurastrum
   Tetraedron
   Trepomonas
   Ulothrix
   Vqlvox

Bacillariophyta
   Achnanthes
   Asterionella
   Caloneis
   Cocconeis
   Cyclotella
   Cymbella
   Diatoma
   Epithemia
   Fragillaria
   Gomphonema
   Hannaea
   Melosira
   Meridion
   Navicula
   Nitzschia
   Opephora
   Rhizosolenia
   Stephanodiscus
   Synedra
   Tabellaria
X

X
X


X
X

X
X
X
X
X
X
X
X
X
X
X
X

X
X
X
X
X
X
X

X
X
X
X
X


X

X

X
X
X
X
X
X
X

X
X
X




X
X

-------
IN3
                 1966
                                                                                                          1974
                                                 Figure 11.    Copepod  levels.

-------
ro
   0.2




   0.1






   0.2




   0.1







£  0-2




|  0.1

t—•
x.



   0.2




   0.1






   0.2




    0.1




      Q
             STfl 1
             STfl 2
            -STfl 3
             .STfl
             .STfl 5
                1966
                      1967
  A.
                                                999
                                                                                       V
1968
1969
1970


TERR
1971
1972
1973
1974
                                            Figure 12.   Cladoceran levels

-------
Two copepods are common in Kootenay Lake, Cyclops bicuspidatus. and
Diaptomus ashlandi, and three cladocerans, Daphnia galeata, Diaphanosoma
leuchtenbergianum, and Bosmina coregoni.  A detailed evaluation of
the seasonal reproductive activity of each of these five species
was made.  Figure 13 presents the total densities of each species
at Station 2.  This is followed in Figure 14 by a summary of those
cladocerans with eggs and copepods with egg sacks.  Note that during
1966-69, Diaptomus reached essentially the same level each summer.
Cyclops on the other hand appeared to be increasing during the three-
summer study.  The years 1971-73 saw increasing summer peaks of
Diaptomus as well as Cyclops.  Daphnia reached substantial densities
during 1967, but was relatively low during 1966 and 1968.  This genus
has continued to decline and during 1971-74 was essentially absent
from the lake.  Diaphano somat in contrast, has increased markedly
during 1971-73, reaching levels second only to Diaptomus.  Bosmina
never has contributed substantially to the total zooplankton pop-
ulation, but recently it has been as abundant as  Daphnia.  These
changes could be induced oy selective predation by landlocked sockeye
salmon (Brooks and Dodson3", Brooks31, Galbraith3^, Warshaw33, Wells31f)
or by competition among zooplankters (Hall jet al..3% Hazelwood and
Parker36).

Although the total copepod density did not vary considerably from
summer to summer during 1966-68, a larger number of individuals
were gravid during 1967 than during the other two years.  Further-
more, even though 1972 was a year of high Diaptomus populations,
only a relatively small proportion of the population was carrying
egg sacks.  Cladocerans also, as exemplified by D iaphano s oma,
exhibited a rather erratic relationship between the size of the
population and the number of gravid members in it.  This may be
due to differences in number of young per brood.  Other possibil-
ities include lower mid-summer natural mortality rates as well as
lower grazing pressure.  Information comparable to that given for
Station 2 in Figures 13 and 14 is given in Figures 15 and 16 for
Station 3, Figures 17 and 18 for Station 4, and in Figures 19 and
20 for Station 5.  Recall that Station 5 is located slightly north
of the point where water leaves the lake via the west arm.
Cladoceran populations are remarkably similar at all four Stations,
although the copepod populations at Station 5 do not appear to
follow the same pattern as those at Stations 2-4 during 1971-74.
Noteworthy is the fact that the population of Diaptomus was
approximately twice as high in 1973 at Stations 2-4 than at
Station 5.
                                   23

-------
PG
           50 -
                 1966
1967
1968
1969
1970
TEflR
                                                                         1971
                                                        1972
                                                        1973
                                                        1974
                                   Figure 13.   Total  zooplankton densities at Station 2.

-------
5
      1966
1967
1968
1969
1970
YEflR
                                                             1971
1972
                                                                   1973
                                                                   1974
                        Figure 14.   Gravid  zooplankton densities at Station 2.

-------
ro
en
                 1966
1967
1968
1969
1970

YEflR
1971
1972
1973
                                   Figure 15.    Total zooplankton densities at Station 3.

-------
ro
      cc
      UJ
      CO
           0


           3
           0
          0.3

           0
                 1966
1967
1968
1969
1970

YEflR
1971
1972
1973
1974
                                   Figure 16.   Gravid  zooplankton densities at Station  3.

-------
ro
oo
           50
      E
      fc
30





20





10




 0


30





20




10
                  1966
                  1967
1968
1969
1970

YEflR
1971
1972
1973
1974
                                    Figure 17.    Total zooplankton densities  at Station 4.

-------
ro
10
                  1966
1967
1968
1969
1970

YEPR
1971
1972
                                                                                                1973
                                                                              1974
                                   Figure 18.    Gravid zooplankton densities at  Station 4.

-------
U)
3
50



40



30



20




10



 0

30



20



10
             0
             3
                  1966
                  1967
1968
1969
1970

YEflR
                                                                          1971
1972
1973
1971*
                                     Figure 19.   Total  zooplankton  densities at Station 5.

-------
0.3
       1966
1967
1968
1969
1970
TEflR
1971
1972
1973
1974
                         Figure  20.    Gravid zooplankton densities at  Station 5.

-------
                               SECTION V

                           SIMULATION MODEL

PARAMETER ESTIMATION

All models of ecological systems contain various rate and proportionality
constants, as well as other coefficients, that must be given specific
values before simulated results can be generated.  Many of these
parameters may be estimated from field or laboratory observations, and
others taken from similar situations reported in the literature.
Unfortunately some quantities cannot be measured, although they exist
and are conceptually important in model development.  In these cases,
it becomes desirable to obtain estimates by fitting part or all of the
model to data gathered from the system under study.  The general
procedure follows .

Suppose the model system is described by the set of differential
equations

                    7i - fi     , I - l,...,n                   (2)

where y' is the time derivative of the i   state variable y, an element
of the vector y_, and £ is a vector of parameters.  For fixed £, the
system may be viewed as consisting of ordinary differential equations.
If, on the other hand, £ is allowed to vary, y! is more appropriately
viewed as the partial differential equation
The effect of changing p^ (j = l,...,m) on the solution y  of this
equation is found by first writing
                      8y          m
                    3(-g~-)/3pj = |(9fi/3yk)(3yk/3pj) + 3fi/9pj-

But the order of differentiation can be reversed yielding

                                                             .        (5)
                     V9P/'    k=l

Now let 9y,/9p., the sensitivity of yfc to p  , be designated as

and rewrite as
                             m
                           = ^(8f./8yt) u,   + 3f./3p..                (6)
                            k=l
                                  32

-------
 Taken over all i and j,  this  produces a system of linear differential
 equations in u that  can  be solved in concert with the original system
 describing state variable behavior through time.

 With this background the approach used to estimate £ proceeds along
 the  following lines.  Suppose  £ are the observed values of _y_ at
 sampling  time T.   Suppose further, that an objective function of the
 form
             II
             Ti
                               - jt>
                                                                        (7)
       or
                        Ti
                        Ti

                                                                        (8)


                                                                        (9)
is selected for minimization  (others  could be justified  including  the
use of y . in the denominator  to reduce computation) .  Now  differentiate
D with respect to p  , D  say, and expand  in  a Taylor Series  around
 initial  approximations
^(2+ ApJ - J, ApJ(3Dk/3p.J)
                                          solution)  to  give
                                               = 0.
                                                                        (10)
The resulting system is linear in, and can be solved repeatedly  for
A£ to update £.  This approach should be recognized as Newton's  method.
Still other techniques can be applied including conjugate gradients
and steepest descent (see, e.g., Powell37).

Now observe, for example, that

                    D  = 3D/9p                                          (11)
                           Ti
and D (£ + A£>
                             1C J- 1
                                y1)aukj/3p.J -
                                                                 0.
                                                                       (12)
Here one is required to compute values of the second derivatives of y.
with respect to all p . > that is , a massive system of n state variable
equations (differential) plus nm sensitivity equations plus nm2 second
derivative equations must be solved at every T, usually numerically.
The last          ^
in D and
                                              ,                    .
         set of nm^ equations can be avoided by expanding y. about p_
         finding the derivative of D with respect to Ap (D' say) :
                                  33

-------
                        Ti      k     j

and         Dl(p + Ap) * IU&. - $Ap a )»   - 0, L - 1,...,m.         (14)
             J           LT1  i   k  kncj ^

To avoid inverting ill-conditioned matrices, the p  should be scaled so
that all parameters are of the same order of magnitude.  Furthermore,
if the magnitudes of the state variables are not of the same order, care
must be taken to scale the n components of the objective function D.
VARIABLES INCLUDED

Parker38*39'1'2 has attempted to create a reliable series of predictive
models that relate the state and driving variables in Kootenay Lake.
The variables used in the most recent version of the model (Parker1)
are given in Table 3.
           Table 3.  VARIABLES USED IN THE NUTRIENT PLANKTON
              MODEL OF THE MIXED LAYER IN KOOTENAY LAKE
     Driving Variables              State Variables
          Inputs                         Summer algal assemblage (group 1)
             Volume flow                 Spring algal assemblage (group 2)
             Inorganic phosphate         Inorganic phosphate
             Nitrate                     Nitrate
             Ammonium                    Ammonium
                                         Copepods
          Temperature                    Cladocerans

          Solar Radiation

          Transparency
GROWTH AND DEATH RATES


Dynamic models based on differential equations require mathematical
descriptions of growth and death processes in terms related to
the driving variables.  The growth rate of the two algal groups
                                  34

-------
 considered  (spring  and  summer  assemblages) were made  functions of
 solar  radiation,  temperature,  and  the three nutrients:  phosphate,
 nitrate,  and  ammonium.   In  addition, mortality rates  due to natural
 causes and  predation were also functions of temperature.  Cladoceran
 and  copepod growth  rate was largely a function of grazing activity
 and  temperature,  mortality  rates largely attributed to temperature.
 Specific  functions  selected to relate algal growth to light intensity
 and  temperature are discussed  in Parker1'^.  Monod relationships
 were used to  describe dependence on the nutrients, with pooled
 nitrogen used as  a  single variable.  All of the underlying relation-
 ships  used  to describe  growth  and mortality rates are given in Table
 4.   In addition,  the differential equations used to describe the
 seven  state variables in the system are tabulated.  Note that hori-
 zontal transport  due to incoming Kootenay River water, as well as
 vertical transfer,  have been incorporated in these equations.
 Essentially,  the  differential  equations for the three nutrients are
 mass balance  forms  which assume that all of the nutrients Ingested
 but  not incorporated into new  zooplankton are immediately recycled.
 Also any nitrate  that has been reduced and used by phytoplankton
 for  growth  will  be returned to the system as ammonium.  Specific
 values used for all of  the  constants shown in Table 4 are summarized
 in Table 5.

 COMPARISON WITH OBSERVED VALUES
The model outlined in Table 4 was developed primarily from informa-
tion gathered during the period 1966-69 while phosphate input was
high.  The primary objective of the modeling effort was to predict
the consequences of reduced phosphate input.  Once the model was
completed and "tuned" to 1966-69 data (Parker 1>39), it was applied
using input data from 1971-74.  Only one constant was changed in
Table 5 for this application.  For use over 1966-69, the half-
saturation constant for phosphate was 1.0 for both algal groups.
This is, of course, a very high figure, its use being consistent
only with very high ambient phosphate levels prior to 1969.  It
was assumed that phytoplankton in the system would slowly adjust
to the new phosphate levels by gradually reducing the half-satur-
ation constant to a more typical value.   A review of model behavior
under different assumptions of reduced half-saturation constant
suggested as appropriate a linear decrease from 1.0 in 1971 to
0.2 in 1974.  Failure to reduce the half-saturation constant resulted
in the virtual loss of the phytoplankton populations in 1973 and 1974,

Simulated values for inorganic phosphate, nitrate, and ammonium are
presented in Figures 21, 22, 23, respectively.  These figures should
be compared to Figures 5, 8, and 9, respectively.
                                  35

-------
                                      Table 4.  THE MODEL  SYSTEM

                                           Growth  rate  (G)
                                                                           Mortality rates
                                                                           Natural     Predation
Algal group 1

Algal group 2

Cladocera (C.)

Copepoda (C
                           (I)f(T)g
                                                                                TB(C11C1+C21C2)
                                                                    C13T

                                                                    C23T
                                                                          C14TC1

                                                                          C24TC2
      I = light intensity
      T - temperature
     S. = nutrients
                                                       f±(T) =  [(T/T8l)exp(l-T/Tal)
                                                                                          ,°1
                                                              B = expt-k(A1+A2)]
    ' A1(GA1 '
                                        Differential equations
                                  -  T3Ai/SY
      Y
"l"
A2(GA2 - ^2 - M2A2> ' VSV9Y

ci(Gci - Mici - 'W - vaci/3Y
  C//n     \r      \f   \   W^f*  J *^V
 2( Cl ~ H.C2 ~  2C2' ~ V3C2/3Y
q(A1M2Al + A2M2A2 - C^ -  C2GC2) - qC^G^ + ^^
                                                                     m31ll/9Z ' V3N1/3Y
                        A2M2A2)  - n2(ClGCl +.C2GC2>  " nl(A!GAl * A2GA2)N3/(N2 + N3)

-------
             sin i
10

 5


10

 5


10
             SIR 2
              SIR 3
CO
              STfl
          10
              STP 5
          10
                1966       1967       1968        1969
                                                   1970
                                                   TEflR
1971        1972       1973       197U
                            Figure 21.    Simulated soluble  inorganic phosphate  concentrations.

-------
             Table  5.   CONSTANTS  USED  IN  THE  SIMULATION MODEL


       an  „   35.              CI;L = 0.70               Kn  = K12  =  1*

       a12  =  0.02 = a21       c12 =0.10               K21  = K22  =  6

       &21  =  8-                C13 =0.03                q  = 0.3

       IS1  =  IS2 =  1<6         C14 = !-5                nl  = 2'°

       TS1  =  20.               cn = 0>3                n2  „ 5.0

       TS2  =  11.               c22 = 0.15                m  = 0.15 x 103

       a1   =  4.80              c23 = 0.015

       a2   =  1.45              C24 = °*5

                              bl   = b2 = 0.47

                              k    =0.35
             K12 decreased linearly from 1 to 0.2 during 1972-74,
The agreement between predicted and observed values for phosphate
is reasonably good except during the summers of 1966 and 1967.
In 1966 there was an influx of phosphate in the Kootenay River
which was not accounted for by the model.  Still, there was more
spring phytoplankton (group 2) model growth than in the lake.

Nitrogen metabolism in the lake is assessed largely in terms of
nitrate and ammonium concentrations.  Examination of Figure 22
and the corresponding Figure 8 for observed values indicates that
the largest deficiency in model output for the period 1966-69
is that the simulated values are too low at times when the
observed nitrate concentrations are high in the lake, resulting
in model values being drawn down too low during mid-summer (see
for example 1968 and the spring of 1969).  During 1971-74 the
model is not as responsive as appears necessary to mimic the actual
situation in Kootenay Lake.  For example predicted winter and
spring values for 1972 are low, and the summer values in 1972 and
1973 appear too high.  Examination of Figures 23 and 9 shows model

                                    38

-------
GO
ID
                1966
1967
1968
1969
1970
TERR
1971
1973
1973
1974
                                        Figure 22.   Simulated  nitrate concentrations.

-------
values being consistent with observed values during periods of low
concentration but  substantially too low during periods of high
ammonium concentration.  This may be due  to inadequate contributions
by  zooplankton during peak periods of growth and contributions from
the sediments during the continuous period of winter circulation.

Figure 24 presents the simulated values for the two algal assem-
blages in Kootenay Lake.  Comparison with Figure 10 shows that the
largest problem area lies in simulating the late summer algal
population.  Assuming that the two assemblages provide a reasonable
breakdown for phytoplankton in Kootenay Lake, the model algal group
1 rarely ever reaches the levels attained in Kootenay Lake.  Appar-
ently nutrient levels in the model are not adequate to produce the
required magnitude in late summer.

Simulated copepod densities are given in Figure 25, for comparison
with observed values in Figure 11.  Although the model values are
reasonably good for 1966-1969, they are substantially low for 1971-
1974.  This is particularly evident in 1972 and 1973.  Again the
cause could lie with the model's failure to produce higher algal
peaks during August, thus producing an Inadequate food supply for
the copepods.  The same problem appears to exist for the model
cladoceran population (Figures 26 and 12).

Observed quarterly means for variables used in the simulation
model are presented in Tables A1-A9 of the Appendix.

HYDRODYNAMIC CONSIDERATIONS
It is clear from the water retention time (566 days) that advection
plays a dominant role in the dynamic aspects of Kootenay Lake.
Figure 27 is indicative of the flow of the Kootenay River at its
point of entrance into the lake.  During periods of peak volume
flow, the velocity of the river reaches approximately one meter
per second.  If the river continued up the lake as a slug of water,
it would move over 600 kilometers in one week.  Conversely, if
mixing were complete, a corresponding input of 1,500 cubic meters
per second would displace one-fortieth of the lake's volume in
one week.  Since the lake is on the order of one hundred kilometers
long, this would suggest a weekly movement of about two and a half
kilometers.  Obviously, the true value lies somewhere between
these two extremes.  Because velocity measurements were not made
during much of the study (then only at Station 2), the model used
the lower bound to calculate expected velocities at each point.
This approach required use of a vertical transfer coefficient

                                    40

-------
STfl 1
10

 5


10

 5


10

 5


10

 5


10
STfi 2
STfl 3
 STfl
                                                                                       "N.
 STfl 5
   1966
                 1967
1968
1969
1970
TERR
                                                          1971
1972
                                                                                   1973
                                                                  19714
                         Figure  23.    Simulated ammonium concentrations.

-------
            STfl 1
           - STfl 2
ro
          ,  - STfl 3
            -STfl 4
            -STfl  5
          I

          0
               1966        1967        1968        1969
1970
YEflR
1971        1972        1973        1974
                                        Figure 24.   Simulated phytoplankton  levels.

-------
0.2

0.1


0.2

0.1


0.2
        SIR 1
       -STR 2
       -SIR 3
~   0.1
       >^J^J^^
    0.2
    -STfl 4
    0.1
                                                                   fs
    o.;
    -STR 5
 0.1
                                                                   L
                                                        '
           1966
                  1967
1968
1969
1970
TERR
1971
1972
                                                                                       1973
1974
                                     Figure  25.    Simulated copepod levels.

-------
0.2 -SIR 1
0.1
0.2

0.1


0.2

0.1


0.2

0.1


0.2

0.1

  0
-STfl 2
-SIR 3
 STfl
-STfl 5
        1966
               1967
1968
1969
1970
YEflR
1971
                                                                            1972
1973
                                                                                               19714
                                  Figure 26.    Simulated cladoceran levels.

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          1.2
          0.9
          0.6
en
                                              X   X
          0.3
                                                  XX
                                                   X
                          »      X


                           X
                                300
600                 900
  CUBIC METERS / SECOND
                                                                                            1200
1500
                                      Figure 27.   Velocity and volume  flow at Station  1.

-------
                           —1     3
of approximately 0.15 cm wk   x 10 , even though studies of some lakes
(Jassby and Powell^0} suggest that this value may be low by an order
of magnitude; molecular transfer is approximately 0.07 cm wk""l x
103.

In order to establish the actual velocities existing in the lake
under different river flows, two additional sampling stations were
established near Station 2.  The first was located midway between
Station 2 and the west bank, and the second was located midway
between Station 2 and the east bank.  Drogue measurements were made
at one, five, and ten meters (occasionally at twenty meters) at
Station 2 as well as at the two new stations.  Figure 28 presents
the results of these measurements for nine days during 1974-75.
These have been ordered according to river flow in an attempt to
focus on patterns of horizontal flow in the vicinity of Station
2.  Recalling that the main axis of the lake lies in a north-
northwest south-southeast direction, it is apparent at once that
the turbulent motion in the lake is extreme.  Only occasionally
are the directions of flow at the three or four sampling depths
coincident, although the magnitudes are similar.  A further con-
solidation of the results is presented in Figure 29. Clearly the
mean northward flow is not coupled strongly with input volume.
There is, however, evidence to support a counterclockwise motion
in the lake, that is, the river water flows more strongly along
the east shore and returns to some extent along the west shore.
This provides for little motion in the center where Station 2 is
located.  Examination of these results point to a rather haphazard
relationship between velocity and volume flow at Station 2, and at
other times southward flow occurs.  In the model, of course, south-
ward flow was never permitted since the river waters were always
presumed to contribute to a northward displacement.  Actual measure-
ments during periods of high flow (greater than 1,500 cubic meters
per second) suggest a northward flow at Station 2 of about 0.2
meters per second, approximately ten times more than that calculated
by volume displacement.  More realism can be expected in the model
if the velocity component is modified accordingly, and the vertical
transfer coefficient changed as well.
                                   46

-------
      (M
            |
                        RIVER FION
                          VOLUie     1262  ttVSEC
                          VELOCITT    0.74  H/SEC
                        omt  6   JUH     TV
                          V
      d
-P»    >-
                        RIVER FLM
                          VOLUME     «S5  M'/3EC
                          VELOCJTT    O.K7 N/SEC
                        DB1E   ITn  JU.     74
                        RIVER FLOH
                          vaue     siv
                          VELOCITT    0.24 M/SEC
                        WTE   29  WC    74
RIVER FLOW
  VOLlfC     1503  HV3EC
  VELOCITT    0.87  K/SEC
OflTE   15   JUN     711
  VOLUHC
  vaacin
DRTE  20
             286  «'/SEC
             o.w H/3EC
            L     TV
                                                                    /           A
RIVER FLOH
  VOLIflC
  VELOCITT
ORTC   12
             199   HV9EC
             0.18
                  74
                                              RIVER FLOH
                                                VOLUME      1186 HV3EC
                                                VELOCm    0.60 M/SEC
                                              ORTE  22   JUH     7U
RIVER FLOH
  VOLUME     489  HV9CC
  VELOCITY    0.91
ORTE   30   JUL
RIVER FLOH
  VOLUC     IU09  tt'/3EC
  VELOCITT    1.10  H/SEC
ORTC   IS   NflT     75
                                                      Figure 28.    Velocity  at  four depths at  Station  2.

-------
       1,0
    UJ
    to
    tn
    
-------
                                SECTION VI

                                REFERENCES


  1.  Parker, R. A.  Some problems associated with computer simulation
           of an ecological system.  In M. S. Bartlett and R.  W.  Hiorns
           (eds.) .   The Mathematical Theory £f_ the Dynamics of_ Biological
           Populations.  Academic Press, London,   pp.  269-288  (1973).

  2.  Parker, R. A.  Capabilities and limitations of a nutrient-plankton
           model.  In E. J. Middlebrooks,  D. H.  Falkenborg, and T.  E.
           Maloney  (eds.).   Modeling the Eutrophication Process.  Utah
           Water Research Laboratory, Logan,  pp.  121-130 (1973).

  3.  Parker, R.  A.  Some consequences of  stochasticizing an ecological
           system model.  In P.  van den Driessche (ed.).   Mathematical
           Problems in Biology»  Victoria Conference.   Lecture  Notes in
           Biomathematics.   Springer-Verlag, Berlin.   2:174-183 (19747.

  4.   Parker, R.  A.   Empirical functions relating  metabolic activity
           in aquatic systems to environmental variables,   ^J.  Fish.
           Res.   Bd.  Caii.   31(9): 1550-1552  (1974).

  5.   Parker, R.  A.   Stability of a nonautonomous  ecosystem model.
           Intern.  J_.  Systems Scl.  6:197-200 (1975).

  6.   Parker,  R.  A.   The influence  of environmental driving variables  on
           the dynamics  of  an aquatic ecosystem model.  Verh. Intern. Verein
           Limnol. 19:47-55  (1975).                     	 	 	'

  7.   Haeler,  A.  D.   Eutrophication of lakes by domestic  drainage.
           Ecology  28:383-395  (1947).

  8.   Edmondson,  W. T.,  C.  C. Anderson,  and  D. R. Peterson.  Artificial
           eutrophication of Lake Washington.  Limnol. Oceanogr.
           1:47-53  (1956).

  9.   Edmondson, W. T.   Changes  in Lake Washington following an
          increase in the nutrient income.  Verh. Int. Ver. Limnol.
           14:167-175  (1961).

10.  Beeton, A. M.   Environmental changes in Lake Erie.  Trans  Amer.
          Fish. Soc.  90:153-159 (1961).

11.  Beeton, A. M.   Eutrophication of St. Lawrence Great Lakes.
          Limnol. Oceanogr. 10:240-254  (1965).

12.  Verduin, J.  Phytoplankton communities .of western Lake Erie
          and the C02 and 0_ changes associated with them.  Limnol.
          Oceanogr. 5:372-380 (1960).

                                 49

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13.  Edmondson, W. T.  Water-quality management and lake eutrophication:
          The Lake Washington case.  In T. H. Campbell and R. 0.
          Sylvester  (eds.). Watery Resources Management and Public
          Policy.  U. of Washington Press, Seattle (1968).

14.  Edmondson, W. T.  The present condition of Lake Washington.
          Verh. Intern. Verein. Limnol. 18:284-291 (1972).

15.  Ahlgren, I.  Changes in Lake Norrviken after sewage diversion.
          Verh. Intern. Verein. Limnol. 18:335-361 (1972).

16.  Malueg, K. W., D. P. Larsen, D. W. Schults, and H. T. Mercier.
          A six-year water, phosphorus, and nitrogen budget for
          Shagawa Lake, Minnesota.  J_. Environ. Quality 4:236-242 (1975),

17.  Taylor, K. G.  Limnological Studies on Kootenay Lake, British
          Columbia, Canada.  Ph.D. Thesis, Washington State
          University, Pullman (1972).

18.  Zyblut, E. R.  Long-term changes in the limnology and
          macrozooplankton of a large British Columbia lake.
          £• Fish. Res. Bd. Can. 27:1239-1250 (1970).

19.  Northcote, T. G.  Some effects of mysid introduction and nutrient
          enrichment on a large oligotrophic lake and its salmonids.
          Verh. Intern. Verein. Limnol. 18:1096-1106 (1972).

20.  Tailing, J. R., and D. Driver.  Some problems in the estimation
          of chlorophyll-^ in phytoplankton.  In R. A.  Vollenweider
          (ed.), 1969, A Manual on Methods for Measuring Primary
          Production in Aquatic Environments.  F.  A.  Davis, Co.,
          Philadelphia. 213 pp. (1969).

21.  Strickland, J.  D. H., and T. R. Parsons.  A Manual of Sea-
          water Analysis.   Fish. Res. Bd. Can. Bull.  No. 125.
          Queens's Printer, Ottawa.  203 pp.(1965).

22.  Standard Methods for the Examination of Water and Wastewater.
          American Public Health Association, Washington,  B.C.
          874 pp.  (1971).

23.  Solorzano, L.  Determination of ammonia in natural waters by
          the phenolhypochlorite method.  Limnol.  Qceanogr.
          14:799-801 (1969).

24.  Chu, S. P.  The influence of the mineral composition of  the
          medium on the growth of planktonic algae.  Part II.  The
          influence of the concentration of inorganic N and
          phosphate P. 'U.  Ecol. 31:109-148 (1943).

                                 50

-------
 25.  Goldberg, E. D., T.  J. Walker,  and A.  Whisenand.   Phosphate
           utilization by diatoms.   Biol. Bull.  101:274-284 (1951).

 26.  Fogg, G. E.  Algal Cultures and Phytoplankton Ecology.   U.  of
           Wisconsin Press,  Madison.   126 pp.  (1965).

 27.  Lackey,  J.  B.   Plankton as  Related to  Nuisance Conditions  in
           Surface Waters.   In F. R.  Moulton and  F.  Hitzel  (eds.)
           Limnological Aspects of Water Supply and  Waste Disposal.
           American Association for  the  Advancement  of  Science,
           Washington,  D.  C.  87  pp.  (1949).

 28.  Thomas,  W.  H.   Phytoplankton nutrient  enrichment  experiments off
           Baja California and in the eastern  equatorial Pacific Ocean.
           £.  Fish.  Res. Bd. Can. 26:1133-1145 (1969).

 29.  Eppley,  R.  W.,  J. N. Rogers, and J.  J. McCarthy.  Half-saturation
           constants  for uptake of nitrate and ammonium by marine
           phytoplankton.  Limnol. Oceanogr. 14(6):912-920  (1969).

 30.  Brooks,  J.  L.,  and S.  I.  Dodson.   Predation, body size,  and
           composition  of plankton.   Science 150:28-35  (1965).

 31.  Brooks,  J.  L. Eutrophication and changes in the composition
           of  the zooplankton.  In Proceedings of a  Symposium,
           Eutrophication;   Causes, Consequences, Correctives.
           National Academy  of  Sciences, Washington, D. C.
           pp.  236-255  (1969).

 32.   Galbraith, M. G., Jr.  Size-selective predation on Daphnia by
           Rainbow Trout and Yellow Perch.  Trans. Amer. Fish. Soc.
           96:1-10 (1967).

 33.   Warshaw,  S.  J.  Effects of Alewives  (Alosa pseudoharengus) on the
           zooplankton of Lake Wononskopomuc,  Connecticut.  Ljjmol.
           Oceanogr. 17:816-825 (1972).

 34.  Wells, L.  Effects of Alewife predation  on zooplankton populations
           in Lake Michigan.   Limnol.  Oceanogr.  15:556-565 (1970).

 35.  Hall, D. J., W. E. Cooper, and E. E. Werner.  An experimental
          approach to the production dynamics  and structure of
           fresh-water animal communities.  Limnol.  Oceanogr.
          15:839-928 (1970).

36.  Hazlewood, D. H., and R. A.  Parker.  Population dynamics of
          some freshwater zooplankton.  Ecology  42:266-274  (1961).

                                     51

-------
37.  Powell, M. J. D.  A FORTRAN subroutine for solving systems of
          non-linear algebraic equations.  UK Atomic Energy Research
          Establishment Report R 5947, Harwell (1968).

38.  Parker, R. A.  Simulation of an aquatic ecosystem.  Biometrics
          24(4):803-821 (1968).

39.  Parker, R. A.  Estimation of aquatic ecosystem parameters.
          Verh. Intern. Verein. Limnol.  18:257-263 (1972).

40.  Jassby, A. and T. Powell.  Vertical patterns of eddy diffusion
          during stratification in Castle Lake, California.  Limnol.
          Oceanogr. 20(4):530-543   (1975).
                                  52

-------
                              SECTION VII

                               APPENDIX
             OBSERVED QUARTERLY MEANS FOR KOOTENAY LAKE
                 VARIABLES USED IN SIMULATION MODEL

Table                                                              Page

 A-l      Quarterly means (number of observations) for Kootenay      54
          River flow (m3/sec) at station 1

 A-2      Quarterly means (number of observations) of               55
          temperature at 1 M (station 1) and mean temperature
          over 10 M (stations 2-5)

 A-3      Quarterly means (number of observations) of the           56
          extinction coefficient (corrected for algal content)
          over 5 M at station 1 and over 10 M at stations 2-5

 A-4      Quarterly means (number of observations) of inorganic     57
          phosphate as uM/L at 1 M (station 1) and mean
          inorganic phosphate over 10 M (stations 2-5)

 A-5      Quarterly means (number of observations of nitrate        58
          concentration as \iVLfL (station 1) and mean nitrate
          concentration over 10 M (stations 2-5)

 A-6      Quarterly means (number of observations) of ammonium      59
          concentration as yM/L at 1  M (station 1) and mean
          ammonium concentration over 10 M (stations 2-5)

 A-7      Quarterly means (number of  observations) of mean          60
          phytoplankton density over 10 M as mg/L (stations
          2-5)

 A-8      Quarterly means (number of  observations) of mean          61
          copepod  density over 10 M as mg/L (stations 2-5)

 A-9      Quarterly means (number of  observations) of mean          62
          cladoceran density over 10  M as mg/L (stations 2-5)
                                  53

-------
Ln
*>
       Table A-l. QUARTERLY MEANS  (NUMBER QF  OBSERVATIONS)  FOR KOQTENAY RIVER FLOW On3/sec) AT STATION 1
Qtr.
1
2
3
4

1966

1300(4)
366(7)
139(3)

1967
207 (1)
1659 (4)
579(8)
163(4)
Year
1968 1969 1971
165(3) 143 C2)
1245(4) 1668(3)
507(8) 484(12)
249(4) 158(2)

1972

899(5)
657(13)
729(4)

1973
140 C3)
247(6)
326(10)
376(4)

1974
842(2)
1344(4)



-------
             Table  A-2. QUARTERLY MEANS  (NUMBER OF OBSERVATIONS)  OF TEMPERATURE AT 1 M (STATION 1)
                                  AND MEAN TEMPERATURE OVER 10 M (STATIONS 2-5)
Ol
Ui
Sta.
Qtr.
1
2

3



4

5



1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4

1966
8.6(4)
17.7(9)
9.9(5)
7.2(4)
16.9(10)
11.6(5)

7.4(4)
17.4(8)
12.7(4)
7.6(4)
17.3(9)
13.0(4)





1967
1.5(1)
10.2(4)
17.5(4)
11.6(4)
5.3(2)
8.7(5)
16.4(4)
13.9(4)
5.1(2)
9.0(5)
17.2(4)
11.3(4)
5.1(3)
9.1(5)
17.2(5)
14.9(3)

31.1(2)
17.3(5)
14.6(4)

1968
3.4(3)
8.0(4)
16.8(8)
5.5(4)
7.9(3)
16.4(8)
8.3(4)
3.4(2)
8.0(4)
16.3(7)
7.3(3)
4.3(1)
7.8(4)
16.4(7)
7.9(3)
3.2(3)
8.8(4)
16.6(8)
11.2(4)
Year
1969
1.5(1)
6.5(3)
2.8(1)
6.9(3)

2.8(2)
7.0(3)


2.3(1)
7.2(3)

2.6(2)
8.4(3)



1971
17.2(11)
5.2(2)
15.7(12)
9.7(2)


16.5(10)
10.5(2)
16.7(10)
10.5(2)


17.0(10)
13.1(1)

1972
8.7(5)
15.2(12)
11.4(4)
7.2(5)
15.5(12)
9.9(4)

7.3(5)
15.5(13)
10.6(4)
7.7(5)
15.6(13)
11.3(4)

7.6(3)
15.7(11)
10.6(3)

1973
0.8(2)
11.2(5)
17.2(8)
7.4(2)
3.2(2)
9.1(5)
17.6(8)
8.2(2)
3.9(3)
5.8(3)


3.6(2)
9.5(5)
17.3(8)
10.0(3)
3.4(1)
11.8(3)
17.1(8)


1974
1.6(1)
8.2(3)
2.2(1)
6.6(3)





1.8(1)
7.4(3)


9.9(2)



-------
      Table A-3.  QUARTERLY MEANS (NUMBERS OF OBSERVATIONS) OF THE EXTINCTION  COEFFICIENT (CORRECTED

                   FOR ALGAL CONTENT) OVER 5 M AT STATION 1 AND OVER 10 M AT  STATIONS  2-5
ui
•en
Sta.
Qtr.
1
2
3
4
5
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4

1966
1.92(2)
0.84(9)
0.85(9)
1.16(4)
0.25(10)
0.17(5)
0.74(4)
0.28(8)
0.23(4)
0.56(3)
0.34(9)
0.24(4)


1967
1.10(1)
3.13(4)
0.98(8)
0.52(4)
0.30(2)
1.15(6)
0.70(8)
0.29(4)
0.23(2)
0.73(6)
0.58(8)
0.42(4)
0.16(3)
0.60(6)
0.57(8)
0.26(3)
0.46(3)
0.56(8)
0.25(4)

1968
1.75(3)
2.05(2)
0.87(8)
0.67(3)
0.92(3)
0.36(8)
0.18(4)
0.17(2)
0.63(4)
0.33(7)
0.18(3)
0.10(1)
0.47(4)
0.32(7)
0.18(3)
0.25(3)
0.34(4)
0.27(8)
0.15(4)
Year
1969
1.54(2)
1.93(3)
0.23(1)
1.01(3)
1.10(2)
0.15(1)
0.91(2)
0.09(2)
0.60(2)

1971 	
0.70(11)
0.79(2)
0.34(12)
0.20(2)
0.31(10)
0.21(2)
0.32(10)
0.18(2)
0.27(10)
0.16(1)

1972
1.90(5)
1.20(12)
0.69(4)
0.37(5)
0.42(12)
0.29(4)
0.36(5)
0.41(13)
0.39(3)
0.34(5)
0.42(13)
0.28(3)
0.26(3)
0.37(11)
0.24(3)

1973
1.32(2)
1.32(6)
1.21(8)
1.75(2)
0.23(2)
0.32(5)
0.40(8)
0.31(2)
0.24(3)
0.24(3)
0.24(2)
0.40(5)
0.34(8)
0.22(2)
0.22(1)
0.33(3)
0.34(8)
0.22(2)

1974
2.58(2)
2.56(4)
0.36(2)
0.33(4)

0.27(2)
0.35(4)


-------
              Table A-4.  QUARTERLY MEANS (NUMBER OF OBSERVATIONS) OF INORGANIC PHOSPHATE AS yM/L
                    AT 1 M (STATION 1) AND MEAN INORGANIC PHOSPHATE OVER 10 M (STATIONS 2-5)
Ul
Sta.
Qtr.
1
2
3
4
5
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4

1966
4.01(4)
7.70(9)
11.54(5)
1.54(4)
3.38(10)
3.00(5)
1.62(4)
3.19(8)
2.73(4)
1.80(4)
2.54(9)
2.14(4)


1967
12.28(1)
2.58(5)
4,28(8)
11.01(4)
2.85(2)
2.40(6)
1.62(8)
2.17(4)
2.78(2)
2.29(6)
1.16(8)
1.99(4)
2.41(3)
2.16(6)
0.94(8)
1.27(3)
1.21(3)
0.51(8)
0.66(4)

1968
9.02(3)
3.65(4)
5.64(8)
3.38(4)
2.66(3)
3.02(8)
2.77(4)
2.91(2)
2.65(4)
2.63(7)
2.57(3)
2.56(1)
2.55(4)
2.37(7)
2.40(3)
2.18(3)
1.55(4)
1.67(8)
1.90(4)
Year
1969
4.73(2)
0.86(3)
3.04(1)
1.93(3)
2.75(2)
1.79(3)
2.93(1)
1.92(3)
2.45(2)
1.60(3)

1971
0.66(11)
1.23(2)
0.40(12)
0.32(2)
0.39(10)
0.38(2)
0.38(10)
0.47(2)
0.27(10)
0.00(1)

1972
0.13(5)
0.07(12)
0.25(4)
0.50(5)
0.06(12)
0.32(4)
0.48(5)
0.03(13)
0.16(4)
0.57(5)
0.03(13)
0.12(4)
0.50(3)
0.01(11)
0.10(3)

1973
1.27(2)
0.48(5)
0.26(8)
0.47(2)
0.60(2)
0.12(5)
0.05(8)
0.36(2)
0.55(3)
0.28(3)
0.54(2)
0.13(5)
0.03(5)
0.18(3)
0.30(1)
0.03(3)
0.02(8)
0.04(2)

1974
0.36(2)
0.24(4)
0.48(2)
0.32(4)

0.42(2)
0.29(4)


-------
                 Table A-5.  QUARTERLY MEANS (NUMBER OF OBSERVATIONS) OF NITRATE CONCENTRATION

                AS viM/L AT 1 M (STATION 1) AND MEAN NITRATE  CONCENTRATION  OVER 10 M (STATIONS 2-5)
Ln
00
Sta.
Qtr.
1
2
3
4
5
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4

1966
1.10(6)
1.20(5)
1.27(8)
1.67(5)
1.56(7)
1.36(4)
1.38(8)
1.43(4)


1967
31.36(1)
8.36(5)
1.88(8)
2.14(4)
3.57(2)
4.48(6)
2.07(8)
3.36(4)
3.71(2)
3.69(6)
2.07(8)
3.79(4)
3.38(3)
3.01(6)
1.99(8)
2.62(3)
1.79(3)
2.02(8)
3.05(4)

1968
7.93(3)
5.45(4)
3.70(8)
4.75(4)
5.31(3)
3.74(8)
4.67(4)
7.50(2)
4.45(4)
3.98(7)
4.60(3)
5.00(1)
3.98(4)
3.62(7)
4.02(3)
6.05(3)
2.53(4)
3.63(8)
4.09(4)
Year
1969
8.71(2)
8.36(3)
7.71(1)
7.52(3)
6.85(2)
7.83(3)
7.57(1)
7.24(3)
7.07(2)
6.26(3)

1971
5.44(11)
3.03(2)
6.24(12)
5.82(2)
5,71(10)
4.72(2)
5.70(10)
3.79(2)
4.46(10)
0.99(1)

1972
6.09(5)
3.39(12)
3.67(4)
8.06(5)
3.17(12)
4.95(4)
7.31(5)
2.91(13)
3.75(4)
7.33(5)
2.86(13)
4.02(4)
5.48(3)
2.36(11)
4.40(3)

1973
8.38(2)
2.90(6)
4.16(8)
5.99(2)
7.66(2)
2.70(5)
3.73(8)
5.92(2)
7.95(3)
4.13(3)
7.59(2)
3.42(5)
3.28(7)
4.10(3)
6.28(1)
1.79(3)
2.96(8)
3.94(2)

1974
17.14(2)
6.64(4)
8.62(2)
6.09(4)

8.71(2)
5.44(4)


-------
Table A-6.  QUARTERLY MEANS (NUMBER OF OBSERVATIONS) OF AMMONIUM CONCENTRATION AS yM/L AT 1 M
            (STATION 1) AND MEAN AMMONIUM CONCENTRATION OVER 10 M  (STATIONS 2-5)
sta.
i
1



2



3



4



5




Qtr. 1966
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4

1967


6.56(1)
4.83(2)

0.82(2)
2.34(5)
2.99(4)

0.42(2)
1.82(6)
1.82(2)

2.71(3)
1.47(7)
4.20(3)

3.03(3)
3.35(5)
1.39(4)

1968
8.16(3)
2.61(2)
2.99(3)
12.35(4)

1.69(3)
1.03(7)
7.51(4)
1.06(1)
2.93(4)
1.52(4)
8.30(3)
0.14(1)
1.66(4)
1.48(5)
7.81(3)
0.61(3)
1.94(4)
0.76(5)
7.81(4)
Year
1969
6.03(2)
1.43(3)


4.02(1)
1.41(3)


7.40(2)
1.03(3)


2.19(1)
1.37(3)


8.64(2)
1.41(3)



1971


5.55(11)
0.90(2)


3.59(12)
0.91(2)


4.50(10)
0.72(2)


4.90(10)
0.77(2)


3.16(10)
1.02(1)

1972

1.91(5)
1.47(12)
2.19(4)

1.61(5)
1.14(12)
2.27(4)

1.85(5)
1.34(13)
2.18(4)

1.54(5)
1.79(13)
2.05(4)

1.25(3)
1.55(11)
2.41(3)

1973
6.00(2)
1.97(6)
1.65(8)
3.25(2)
4.53(2)
2.14(5)
1.34(8)
1.18(2)
2.62(3)
2.24(3)


6.57(2)
2.21(5)
1.32(7)
1.11(3)
5.10(1)
2.08(3)
1.24(8)
1.33(2)

1974
1.95(2)
3.55(4)


1.40(2)
1.65(4)






1.59(2)
1.78(4)







-------
Table A-7.  QUARTERLY MEANS (NUMBER OF OBSERVATIONS) OF MEAN PHYTOPLANKTON
                DENSITY OVER 10 M AS mg/L {STATIONS 2-5)
Sta.
Qtr.
2
3
4
5
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4

1966
0.64(4)
1.30(10)
0.42(5)
0.26(4)
1.14(8)
0.36
0.22(4)
0.87(9)
1.00(4)


1967
0.20(1)
0.90(6)
0.61(8)
0.60(4)
0.10(1)
0.54(5)
0.41(8)
0.61(4)
0.70(1)
0.60(4)
0.46(8)
0.45(3)
0.35(3)
0.49(8)
0.54(4)

1968
0.90(3)
0.77(8)
0.79(4)
0.42(2)
0.96(4)
0.59(6)
0.83(3)
0.55(1)
0.81(4)
0.58(6)
0.98(3)
0.47(3)
0.88(4)
0.57(7)
0.71(4)
Year
1969
0.05(1)
1.42(3)
0.75(2)
1.52(3)
0.50(1)
1.32(3)
0.90(2)
1.68(3)

1971
0.77(12)
0.67(2)
1.31(10)
0.55(2)
0.86(10)
0.73(2)
1.08(10)
1.48(1)

1972
0.58(5)
0.76(12)
0.37(4)
0.53(5)
0.79(13)
0.47(4)
0.37(5)
0.87(13)
0.43(4)
0.68(3)
0.93(11)
0.54(3)

1973
0.17(2)
1.00(5)
0.73(8)
0.32(2)
0.30(3)
0.85(3)
0.32(2)
0.75(5)
0.53(7)
0.49(3)
0.35(1)
0.73(3)
0.38(8)
0.58(2)

1974
0.20(2)
0.63(4)

0.30(2)
0.87(4)


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Table A-8.  QUARTERLY MEANS (NUMBER OF OBSERVATIONS) OF MEAN COPEPOD DENSITY
                     OVER 10 M AS mg/L (STATIONS 2-5)
Sta.

2
3
4
5
Qtr.
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
1966
0.017(3)
0.033(9)
0.029(4)
0.007(3)
0.041(7)
0.636(3)
0.013(3)
0.063(9)
0.037(3)

1967
0.008(2)
0.039(6)
0.075(8)
0.046(4)
0.013(1)
0.030(6)
0.076(8)
0.035(4)
0.010(3)
0.041(6)
0.057(8)
0.044(3)
0.034(3)
0.099C8)
0.45C4)
1968
0.014(3)
0.068(7)
0.050(4)
0.007(2)
0.018(4)
0.067(6)
0.038(3)
0.006(1)
0.054(4)
0.111(6)
0.045(3)
0.062(3)
0.109(8)
0.044(4)
Year
1969
0.002(1)
0.002(1)
0.009(2)
0.005(3)
0.026(1)
0.004(3)
0.021(3)

1971
0.066(11)
0.054(2)
0.068(10)
0.073(2)
0.083(9)
0.042(2)
0.154(10)
0.130(1)

1972
0.018(4)
0.076(12)
0.025(4)
0.008(5)
0.077(13)
0.066(4)
0.018(4)
0.084(13)
0.050(4)
0.010(3)
0.076(10)
0.050(3)

1973
0.014(2)
0.107(5)
0.155(7)
0.013(2)
0.018(3)
0.018(2)
0.018(2)
0.049(5)
0.119(6)
0.030(3)
0.007(1)
0.049(2)
0.096(6)
0.098(2)

1974
0.014(2)
0.005(4)

0.031(2)
0.014(4)


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                     Table A-9. QUARTERLY MEANS  (NUMBER OF OBSERVATIONS)  OF MEAN CLADOCERAN
                                   DENSITY  OVER  10 M AS mg/L (STATIONS 2-5) .
Ol
Sta.
Qtr.
2



3



4



5



1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4

1966

0.000(3)
0.026(9)
0.002(4)

0.000(3)
0.035(7)
0.004(3)

0.000(3)
0.024(9)
0.003(3)





1967
0.000(2)
0.000(6)
0.060(8)
0.048(4)
0.000(1)
0.000(6)
0.036(8)
0.029(4)
0.000(3)
0.000(6)
0.050(8)
0.044(3)

0.000(3)
0.043(8)
0.011(4)

1968

0.000(3)
0.038(7)
0.010(4)
0.000(2)
0.000(4)
0.020(6)
0.001(3)
0.000(1)
0.000(4)
0.015(6)
0.001(3)

0.000(3)
0.010(8)
0.001(4)
Year
1969
0.000(1)
0.000(3)


0.000(2)
0.000(3)


0.000(1)
0.000(3)



0.000(3)



1971


0.015(11)
0.004(2)


0.012(10)
0.005(2)


0.014(9)
0.003(2)


0.020(10)
0.007(1)

1972

0.000(4)
0.016(12)
0.001(4)

0.000(5)
0.010(13)
0.007(4)

0.000(4)
0.009(13)
0.007(4)

0.000(3)
0.009(10)
0.001(3)

1973
0.000(2)
0.000(5)
0.070(7)
0.004(2)
0.000(3)
0.000(2)


0.000(2)
0.000(5)
0.063(6)
0.008(3)
0.000(1)
0.000(2)
0.026(6)
0.036(2)

1974
0.000(2)
0.000(4)






0.000(2)
0.000(4)







-------
                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
 1. REPORT NO.
       EPA-600/3-76-063
                                                            3. RECIPIENT'S ACCESSION NO.
 4. TITLE AND SUBTITLE
     Phosphate Reduction  and  Response of Plankton
     Populations in Kootenay  Lake
             5. REPORT DATE
                    1976
May
             6. PERFORMING ORGANIZATION CODE
 7. AUTHOR(S)
      Richard A. Parker
                                                            8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
                   I

     Washington State University
     Pullman, Washington  99163
             10. PROGRAM ELEMENT NO.

                 1BA608	
             11. CONTRACT/GRANT NO.

                 R 800430
 12. SPONSORING AGENCY NAME AND ADDRESS

      Corvallis Environmental  Research Laboratory
      Environmental Protection Agency
      200 S.W. 35th St.	  Corvallis, Oregon   97330
              13. TYPE OF REPORT AND PERIOD COVERED
                 Final Report
             14. SPONSORING AGENCY CODE
                      EPA-ORD
 15. SUPPLEMENTARY NOTES
 16. ABSTRACT
           The purpose of  this research project was to determine the  effects of
      reducing by 90 percent  the soluble inorganic  phosphate input to Kootenay
      Lake, British Columbia,  Canada, a significant link in the Columbia River
      system governed by United States-Canadian treaty.  Measurements on temperature,
      transparency, inorganic  and organic phosphate, nitrate, ammonium,  chlorophyll a_,
      copepods, and cladocerans were made during  1971-75, and compared with
      observations made for three years prior to  phosphate reduction  in  1969.  Only
      a slight decrease in chlorophyll occurred,  although there were  important
      changes in species composition.  Total zooplankton levels were  not affected,
      however one genus (Daphnia) has virtually disappeared.  Data indicate that
      primary production in the lake was nitrogen limited prior to 1969, phosphate
      limited two years later.   These changes may also be related to  the completion
      ^n 1972 of Libby Dam in  Montana, upstream from the lake on the  Kootenay River.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                              b.lDENTIFJERS/OPEN ENDED TERMS
                           c. COS AT I Field/Group
     Plankton response
     phosphate reduction
  Kootenay Lake
                                                                             Q8H
 8. DISTRIBUTION STATEMENT


     Release Unlimited
19. SECURITY CLASS (ThisReport)
   Unclassified
           21. NO. OF PAGES
                 72
20. SECURITY CLASS (This page)
   Unclassified
                           22. PRICE
EPA Form 2220-1 (9-73)
                                             63
                             U.S. GOVERNMENT PRINTING OFFICE: I976-S97.3I6/95 REGION 10

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