U.S. ENVIRONMENTAL PROTECTION AGENCY
           NATIONAL EUTROPHICATION SURVEY
                    WORKING PAPER SERIES
                                        REPORT
                                          ON
                                     BLACK HAWK LAKE
                                       SACCOUNIY
                                         IOWA
                                     EPA REGION VII
                                  WORKING PAPER No, 496
CORVALLIS ENVIRONMENTAL RESEARCH LABORATORY - CORVALLIS, OREGON
                            and
ENVIRONMENTAL MONITORING & SUPPORT LABORATORY - LAS VEGAS, NEVADA
 699-440

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                                                                c
                                   REPORT
                                     ON
                              BLACK HAWK LAKE
                                 SAC COUNTY
                                    IOWA
                               EPA REGION VII
                           WORKING PAPER No,  496
      WITH THE COOPERATION OF THE
IOWA DEPARTMENT OF ENVIRONMENTAL QUALITY
                AND THE
          IOWA NATIONAL GUARD
              AUGUST,  1976

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                                   CONTENTS
                                                               Page
  Foreword                                                      ii
  List of Iowa Study Lakes                                      iv
  Lake and Drainage Area Map                                     v
                                                                   v
  Sections
  I.   Conclusions                                                1
 II.   Lake and Drainage Basin Characteristics                    3
III.   Lake Water Quality Summary                                 4
 IV.   Nutrient Loadings                                          8
  V.   Literature Reviewed                                       12
 VI.   Appendices                                                13

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                                 ii
                          FOREWORD
    The National Eutrophication Survey was initiated in 1972  in
response to an Administration commitment to investigate the nation-
wide threat of accelerated eutrophication to freshwater lakes and
reservoirs.

OBJECTIVES

    The Survey was designed to develop, in conjunction with state
environmental agencies, information on nutrient sources, concentrations,
and impact on selected freshwater lakes as a basis for formulating
comprehensive and coordinated national, regional, and state management
practices relating to point-source discharge reduction and non-point
source pollution abatement in lake watersheds.

ANALYTIC APPROACH

    The mathematical and statistical procedures selected for  the
Survey's eutrophication analysis are based on related concepts that:

        a.  A generalized representation or model relating
    sources, concentrations, and impacts can be constructed.

        b.  By applying measurements of relevant parameters
    associated with lake degradation, the generalized model
    can be transformed into an operational representation of
    a lake, its drainage basin, and related nutrients.

        c.  With such a transformation, an assessment of the
    potential for eutrophication control can be made.

LAKE ANALYSIS

    In this report, the first stage of evaluation of lake and water-
shed data collected from the study lake and its drainage basin is
documented.  The report is formatted to provide state environmental
agencies with specific information for basin planning [§303(e)], water
quality criteria/standards review [§303(c)], clean lakes [§314(a,b)J,
and water quality monitoring [§106 and §305(b)] activities mandated
by the Federal Water Pollution Control Act Amendments of 1972.

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                                 m
    Beyond the single lake analysis, broader based correlations
between nutrient concentrations (and loading) and trophic condi-
tion are being made to advance the rationale and data base for
refinement of nutrient water quality criteria for the Nation's
freshwater lakes.  Likewise, multivariate evaluations for the
relationships between land use, nutrient export, and trophic
condition, by lake class or use, are being developed to assist
in the formulation of planning guidelines and policies by EPA
and to augment plans implementation by the states.

ACKNOWLEDGMENT

    The staff of the National Eutrophication Survey (Office of
Research & Development, U. S. Environmental  Protection Agency)
expresses sincere appreciation to the Iowa Department of Environ-
mental Quality for professional involvement, to the Iowa National
Guard for conducting the tributary sampling phase of the Survey,
and to those wastewater treatment plant operators who voluntarily
provided effluent samples and flow data.

    The staff of the Water Quality Division of the Department of
Environmental Quality provided invaluable lake documentation and
counsel during the Survey, reviewed the preliminary reports, and
provided critiques most useful in the preparation of this Working
Paper series.

    Major General Joseph G. May, the Adjutant General of Iowa,
and Project Officer Colonel Cleadeth P. Woods, who directed the
volunteer efforts of the Iowa National Guardsmen, are also grate-
fully acknowledged for their assistance to the Survey.

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                                    IV
LAKE NAME

Ahquabi
Big Creek Reservoir
Black Hawk
Clear
Darl ing
Lost Island
MacBride
Prairie Rose
Rathbun Reservoir
Red Rock Reservoir
Rock Creek
Silver
Spirit
Viking
West Okoboji
NATIONAL EUTROPHICATION  SURVEY

         STUDY LAKES

        STATE OF IOWA

                            COUNTY
                            Warren
                            Polk
                            Sac
                            Cerro Gordo
                            Washington
                            Clay, Palo Alto
                            Johnson
                            Shelby
                            Appanoose, Wayne
                            Marion
                            Jasper
                            Worth
                            Dickinson
                            Montgomery
                            Dickinson

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    Iowa
Map Location
BLACK  HAWK  LAKE

 <8> Tributary Sampling Site
 X Lake Sampling Site
•Z3 Drainage Area Boundary
       1   Scale  2
                                                                  4215—
                         3 Mi.
            9505
                                                9500
                                                                  42*10-

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                             BLACK HAWK LAKE
                             STORE! NO. 1903

I.  CONCLUSIONS
    A.  Trophic Condition:
            Survey data indicate that Black Hawk Lake is  eutrophic.
        This lake ranked fourteenth in overall  trophic quality when
        the 15 Iowa lakes and reservoirs sampled in 1974  were com-
        pared using a combination of six parameters*.  Thirteen of the
        water bodies had less median total  phosphorus, 11  had less
        median dissolved phosphorus, four had less and one had the
        same median inorganic nitrogen, 13 had less mean  chlorophyll
        a_, and all of the other water bodies had greater  Secchi disc
        transparency.
            Survey limnologists did not observe surface concentrations
        of algae, but the numbers of phytoplankton in July and Sep-
        tember indicate blooms at those times (see page 6).
    B.  Rate-Limiting Nutrient:
            The algal assay results indicate that Black Hawk Lake
        was phosphorus limited at the time the assay sample was
        collected (04/19/74).  The lake data indicate phosphorus
        limitation in April but nitrogen limitation in September.
    C.  Nutrient Controllability:
            1.  Point sources—During the sampling year,  the phos-
* See Appendix A.

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                             2
phorus contributions of domestic point sources amounted to
1.2% of the total phosphorus load.  All of this load is
attributed to lakeshore septic tanks, but a shoreline survey
would be necessary to determine the actual significance of those
sources.
    The present loading of 0.55 g/m2/year is well  over that
proposed by Vollenweider (Vollenweider and Dillon, 1974) as
a eutrophic loading (see page 11).  Because this lake is phos-
phorus limited at least part of the time, the incoming phos-
phorus load should be reduced to the greatest practicable extent.
    2.  Non-point sources--The phosphorus contribution of non-
point sources accounted for 98.8% of the total phosphorus load
during the sampling year.  The Unnamed Stream B-l  contributed
79.6%, and ungaged tributaries were estimated to have contrib-
uted 16.0% of the, load.

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II.   LAKE AND DRAINAGE  BASIN  CHARACTER1STICSf
     A.   Lake Morphemetry   :
         1.   Surface area:  3.72  kilometers2.
         2.   Mean  depth:  1.7 meters.
         3.   Maximum depth:   3.7  meters.
         4.   Volume:  6.324 x 106 m3.
         5.   Mean  hydraulic retention time:  271 days.
     B.   Tributary and  Outlet:
         (See Appendix  C for  flow data)
         1.   Tributaries -
                                              Drainage       Mean flow
             Name                              area  (km2)*    (m3/sec)*
             Unnamed Stream B-l                    47.1           0.21
             Minor tributaries &
              immediate drainage  -                   9.5           0.06
                           Totals                 56.6           0.27
         2.   Outlet -
             Unnamed Stream A-l                    60.3**         0.27
     C.   Precipitation***:
         1.   Year  of sampling:  83.7 centimeters.
         2.   Mean  annual:  72.6 centimeters.
 t  Table of  metric  conversions—Appendix B.
 tt Harrison,  1975.
 *  For  limits  of accuracy,  see Working Paper No. 175,  "...Survey Methods,
   1973-1976".
 ** Includes area of  lake.
 *** See Working Paper No.  175.

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                                       4
III.  LAKE WATER QUALITY SUMMARY
      Black Hawk Lake was sampled three times during  the open-water
  season of 1974 by means of a pontoon-equipped Huey  helicopter.   Each
  time, samples for physical and chemical  parameters  were collected
  from a number of depths at two stations  on the lake (see map,  page
  v).   During each visit, a single depth-integrated (near bottom to
  surface) sample was composited from the  stations  for phytoplankton
  identification and enumeration; and during the first visit,  a  single
  18.9-liter depth-integrated sample was composited for algal  assays.
  Also each time, a depth-integrated sample was collected from each
  of the stations for chlorophyll ^analysis.  The  maximum depth sampled
  at each of the stations was 0.6 meters.
      The sampling results are presented in full in Appendix D and are
  summarized in the following table (the July nutrient samples were
  not preserved properly and were not analyzed).

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PARAMETER
TEMP (0
DISS OXY (MG/L)
CNDCTVY (MCftOMO)
PH (STAND UNITS)
TOT ALK (MG/L)
TOT P (MG/L)
ORTHO P (MG/L)
N02»N03 (MG/L)
AMMONIA (MG/L)
KJEL N  (MG/L)
1NORG N (MG/L)
TOTAL N (MG/L)
CHLRPYL A (UG/L)
SECCHI  (METERS)
        A. SUMMARY OF PHYSICAL AND

        1ST SAMPLING ( 4/19/74)
              2 SITES
      RANGE        MEAN   MEDIAN
  12.4  -  12.7    12.5    12.5
«««**•  -«•«•»*«*•«*«••••*•*••*
  186.  -  187.    187.    187.
   8.6  -   8.6     8.6     8.6
  168.  -  177.    173.    173.
 0.161  - 0.168   0.164   0.164
 0.012  - 0.013   0.012   0.012
 2.150  - 2.390
 0.040  - 0.060
 1.400  - 1.800
 2.190  - 2.450
 3.790  - 3.950
                                                        CHEMICAL CHARACTERISTICS FOR BLACK HAWK LAKE
                                                         STORET CODE 1903
  50.3  -  59.3
   0.2  -   0.2
2.270   2.270
0.050   0.050
1.600   1.600
2.320   2.320
3.870   3.870
 54.8
  0.2
                                                                   2ND SAMPLING ( 7/ 3/74)
                                                                         2 SITES
                          RANGE
                      24.5  -  25.2
                                8.0
                      456.  -  467.
                       8.9  -   8.9
                              MEAN   MEDIAN
                              24.9    24.9

                              462.    462.
                               8.9     8.9
                             »«**•*•***•••
54.8
 0.2
«•*•*•  -«**>***••**••••«****•»
»«*•••  _•**•*«•*•»•»****•*•••*
«•««*»  _****»«*»***«*•*••***•*
•••*••  _*»***»*•«•*••*»»*»•*•«
«»****  _•»«•*••**•••*•••*••»»«
««*•**  -«***•*•>***«*«•*«»**•*
  43.7  -  43.7    43.7    43.7
   0.4  -   0.4     0.4     0.4
       3RD SAMPLING ( 9/25/74)
             2 SITES
     RANGE        MEAN   MEDIAN
 14.6  -  15.2    14.9    14.9
  8.6  -   9.0     8.8     8.8
 321.  -  323.    322.    322.
  8.1  -   8.2     8.2     8.2
 145.  -  148.    146.    145.
0.181  - 0.198   0.191   0.193
0.019  - 0.024   0.022   0.022
0.040  - 0.070   0.955   0.055
0.060  - 0.070   0.067   0.070
1.600  - 1.700
0.110  - 0.130
1.640  - 1.770
 45.7  -  49.7
  0.3  -   0.3
                                                                   1.625   1.600
                                                                   0.122   0.125
                                                                   1.680
47.7
 0.3
1.655
 47.7
  0.3

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B.  Biological characteristics:

    1.  Phytoplankton -
        Sampling
        Date

        04/19/74
        07/03/74
        09/25/74
    2.   Chlorophyll  a_ -

        Sampling
        Date

        04/19/74
        07/03/74
        09/25/74
Dominant
Genera

1.  Nitzschia sp.
2.  StejahanocTiscus sp.
3.  Flage!1ates
4.  Cryptomonas sp.
5.  Ankistrodesmus sp.
    Other genera

            Total

1.  Aphanizomenon sp.
2.  Sphaerocystis sp.
3.  Oocystis sp.
4.  Crucigem'a sp.
5.  Stephanodiscus sp.
    Other genera

            Total

1.  Merismopedia sp.
2.  Oscillatoria sp.
3.  Flagellates
4.  Aphanizomenon sp.
5.  Stephanodiscus sp.
    Other genera

            Total
Station
Number

  1
  2

  1
  2

  1
  2
Algal Units
per ml	

 20,657
 16,611
  9,796
  3,194
  2,875
  5.964

 59,097

  9,323
  6,447
  5,612
  1,160
    835
  1.855
 25,232

 28,092
  3,904
  3,140
  2,885
  2,631
 13.665

 54,317
Chlorophyll a
(ug/D

    50.3
    59.3
    43.7

    45.7
    49.7

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                                 7
C.  Limiting Nutrient Study:
    1.  Autoclaved,  filtered,  and nutrient spiked  -
                         Ortho P          Inorganic  N     Maximum yield
        Spike (mg/1)     Cone, (mg/1)      Cone,  (mg/1)    (mg/l-dry wt.)
        Control              0.040             2.380           15.6
        0.050 P              0.090             2.380           29.4
        0.050 P  + 1.0 N     0.090             3.380           32.0
        1.0 N               0.040             3.380           15.2
    2.  Discussion -
            The  control  yield  of the assay alga, Selenastrum  capri-
        cornutum, indicates that the potential  primary  productivity
        of Black Hawk Lake was high at the time the  sample  was  col-
        lected (04/19/74).  The addition of only phosphorus pro-
        duced a  significant increase in yield,  but no such  increase
        occurred with the addition of  only nitrogen.  Therefore,
        phosphorus limitation  is indicated.
            The  lake data substantiate phosphorus  limitation  during
        April (the mean inorganic nitrogen/orthophosphorus  ratio
        was 193/1).   However,  nitrogen limitation  is indicated  in
        September (the mean N/P ratio  was 6/1).

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                                      8
IV.   NUTRIENT LOADINGS
     (See Appendix E for data)
     For the determination of nutrient loadings,  the  Iowa  National
 Guard collected monthly near-surface grab samples  from  each of  the
 tributary sites indicated on the map (page v), except for the high
 runoff months of April, May, and June when two samples  were collected.
 Sampling was begun in August,  1974,  and  was completed in  July,  1975.
     Through an interagency agreement, stream flow  estimates for the
 year of sampling and a "normalized"  or average year  were  provided by
 the Iowa District Office of the U.S.  Geological  Survey  for the
 tributary sites nearest the lake.
     In this report, nutrient loads for sampled tributaries were
 determined by using a modification of a  U.S.  Geological Survey  computer
 program for calculating stream loadings*.
     Nutrient loads for unsampled "minor  tributaries  and immediate
 drainage" ("II" of U.S.G.S.) were estimated using  the nutrient  loads
 at  station B-l, in kg/km2/year,  and  multiplying  by the  II area  in km2.
     No known point sources impacted  Black Hawk Lake  during the  sampling
 year.
 *  See Working  Paper No.  175.

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                                     9
    A.  Waste Sources:
        1.  Known municipal - None
        2.  Known industrial - None
    B.  Annual Total Phosphorus Loading - Average Year:
        1.  Inputs -
                                              kg P/          % of
            Source                            yr             total
            a.  Tributaries (non-point load) -
                Unnamed Stream B-l            1,620           79.6
            b.  Minor tributaries & immediate
                 drainage (non-point load) -    325           16.0
            c.  Known municipal STP's - None
            d.  Septic tanks* -                  25            1.2
            e.  Known industrial - None
            f.  Direct precipitation** -      	65_            3.2
                        Total                 2,035          100.0
        2.  Outputs -
            Lake outlet - Unnamed Stream A-l   1,635
        3.  Net annual P accumulation - 400 kg.
* Estimate based on five parks, two camps, and 55 lakeshore dwellings
  (LeFevre, 1976); see Working Paper No. 175.
** See Working Paper No. 175.

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                                     10
    C.  Annual Total Nitrogen Loading - Average Year:
        1.  Inputs -
                                              kg N/          % of
            Source                            y_r	          total
            a.  Tributaries (non-point load) -
                Unnamed Stream B-l            62,890          78.1
            b.  Minor tributaries & immediate
                 drainage (non-point load) -  12,680          15.8
            c.  Known municipal STP's - None
            d.  Septic tanks* -                  905           1.1
            e.  Known industrial - None
            f.  Direct precipitation** -       4,015           5.0
                        Total                 80,490         100.0
        2.  Outputs -
            Lake outlet - Unnamed Stream A-l  23,995
        3.  Net annual N accumulation - 56,495 kg.
    D.  Non-point Nutrient Export by Subdrainage Area:
        Tributary                             kg P/km2/yr    kg N/km2/yr
        Unnamed Stream B-l                        34             1,335
* Estimate based on five parks, two camps, and 55 lakeshore dwellings
  (LeFevre, 1976); see Working Paper No. 175.
** See Working Paper No. 175.

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                                11
E.   Yearly Loads:
        In the following table,  the existing phosphorus loadings
    are compared to those proposed  by Vollenweider (Vollenweider
    and Dillon, 1974).   Essentially, his "dangerous"  loading is
    one at which the receiving water would become eutrophic or
    remain eutrophic; his "permissible" loading is that which
    would result in the receiving water remaining oligotrophic
    or becoming oligotrophic if  morphometry permitted.   A meso-
    trophic loading would be considered one between "dangerous"
    and "permissible".
        Note that  Vollenweider's model  may not be applicable to
    water bodies with short hydraulic retention times.
                              Total  Phosphorus       Total  Nitrogen
    	Total   Accumulated'    Total    Accumulated
    grams/m2/yr             0.55       0.11        21.6       15.2
    Vollenweider phosphorus  loadings
     (g/m2/yr) based on mean depth and mean
     hydraulic retention time of Black Hawk Lake:
        "Dangerous"  (eutrophic loading)             0.30
        "Permissible"  (oligotrophic loading)        0.15

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                                    12

V.  LITERATURE REVIEWED

    Harrison, Harry M., 1975.  Personal communication (lake morphometry),
        IA Cons. Comm., Des Moines.

    Le Fevre, John, 1976.  Personal communication (shoreline dwellings
        at Black Hawk Lake).  IA Dept. of Env. Qual., Spencer.

    Vollenweider, R. A., and P. J. Dillon, 1974.  The application of
        the phosphorus loading concept to eutrophication research.
        Natl. Res. Council of Canada Pub!. No. 13690, Canada Centre
        for Inland Waters, Burlington, Ontario.

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VI.  APPENDICES
                                  APPENDIX A
                                  LAKE  RANKINGS

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LAKE DATA TO BE USED IN RANMNGS
LAKE
CODE  LAKE NAME

1901  LAKE ACQUAdI

1902  BIG CREEK RESESVOIR

1903  BLACK HAWK LAKE

1904  CLEAR LAKE

1905  LAKE DARLING

1906  LOST ISLAND LAKE

1907  LAKE MACBRIDE

1908  PRAIRIE ROSE LAKE

1909  RATHBUN RESERVOIR

1910  RED ROCK LAKE

1911  ROCK CREEK LAKE

1912  SILVER LAKE

1913  SPIRIT LAKE

1914  VIKING LAKE

1915  WEST LAKE OKOBOJI
MEDIAN
TOTAL ?
0.062
0.046
0.185
0.059
0.077
0.146
0.061
0.056
0.071
0.180
0.065
0.193
0.041
0.075
0.046
MEDIAN
INO«G N
0.3J5
6.465
0.130
0.070
1.475
0.065
2.035
0.210
1.170
1.880
1.400
0.565
0.090
0.130
0.060
500-
MEAN SEC
469.333
436.500
488.167
465.125
482.500
421.167
458.444
463.667
475.889
473.400
480.500
482.667
422.667
459.000
380.444
MEAN
CMLOrtA
8.600
16.867
49.740
17.400
13.817
36.100
17.067
17.350
12.039
14.730
18.367
95.300
12.622
26.033
7.722
15-
MIN 00
8.200
14.800
15.000
8.600
9.200
8.400
15.000
8.600
14.000
14.000
8.400
10.000
9.000
14.200
15.000
MEDIAN
DISS OKTnO P
0.009
0.011
0.020
0.010
0.012
0.021
0.010
0.010
0.008
0.104
0.007
0.034
0.007
0.017
0.017

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PERCENT OF LAKES WITH HIGHER VALUES (NUMBER OF LAKES WITH HIGHER VALUES)

LAKE
CODE  LAKE NAME

1901  LAKE ACOUABI

1902  BIG CREEK RESERVOIR

1903  BLACK HAWK LAKE

1904  CLEAR LAKE

1905  LAKE DARLING

1906  LOST ISLAND LAKE

1907  LAKE M4CBRIOE

1908  PRAIRIE ROSE LAKE

1909  RATHBUN RESERVOIR

1910  RED ROCK LAKE

1911  ROCK CREEK LAKE

1912  SILVER LAKE

1913  SPIRIT LAKE

1914  VIKING LAKE

1915  WEST LAKE OKOdOJI
MEDIAN
TOTAL P
57
89
7
71
29
21
64
79
43
1*
50
0
100
36
P9
( 8)
< 12)
( 1)
( 10)
( 4)
( 3)
( 9)
< ID
( 6)
( 2>
( 7)
( 0)
( 14)
( 5)
( 12)
MEDIAN
INO*G N
50 (
0 (
68 (
86 (
21 (
93 (
7 (
57 (
36 (
14 (
29 (
43 (
79 (
68 (
100 (
7)
0)
9)
12)
3)
13)
1)
8)
5)
2)
4)
6)
11)
9)
14)
500-
MEAN SEC
43 (
79 <
0 (
50 (
14 (
93 (
71 (
57 (
29 (
36 (
21 <
7 (
86 (
64 (
100 (
6)
11)
0)
7)
2)
13)
10)
8)
4)
5)
3)
1)
12)
9)
14)
MEAN
C*LORA
93 (
57 (
7 (
36 (
71 (
14 (
50 (
43 <
86 (
64 (
29 (
0 (
79 (
21 (
100 (
13)
8)
1)
5)
10)
2>
7)
6)
12)
9)
4)
0)
11)
3)
14)
15-
MIN DO
100 (
21 <
7 (
75 (
57 (
89 (
7 <
75 (
39 (
39 (
89 (
50 <
64 (
29 (
7 (
14)
3)
0)
10)
8)
12)
0)
10)
5)
5)
12)
7)
9)
4)
0)
MEDIAN
DISS ORTHO P
79 (
50 (
21 (
64 (
43 (
14 (
64 (
64 (
86 (
0 (
96 (
7 (
96 (
32 (
32 I
11)
7)
3)
8)
6)
2)
8)
8)
12)
0)
13)
1)
13)
4)
4)
INDEX
NO
422
296
110
382
235
324
263
375
319
167
314
107
504
250
428

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LAKES RANKED BY INDEX NOS.




RANK  LAKE CODE  LAKE NAME               INDEX NO






   1  1913       SPIRIT LAKE                504




   2  1915       WEST LAKE OK080JI          428



   3  1901       LAKE ACOUABI               <»22




   4  1904       CLEAR LAKE                 382




   5  1908       PRAIRIE ROSE LAKE          375




   6  1906       LOST ISLAND LAKE           324




   7  1909       RATHBUN RESERVOIR          319




   8  1911       ROCK CREEK LAKE            314



   9  1902       BIG CREEK RESERVOIR        296



  10  1907       LAKE MACBRIDE              263



  11  1914       VIKING LAKE                250



  12  1905       LAKE DARLING               235



  13  1910       RED ROCK LAKE              167




  14  1903       BLACK HAWK LAKE            110



  15  1912       SILVER LAKE                107

-------
    APPENDIX B
CONVERSION FACTORS

-------
                CONVERSION FACTORS

Hectares x 2.471 = acres
Kilometers x 0.6214 = miles
Meters x 3.281 = feet
                         -4
Cubic meters x 8.107 x 10   = acre/feet
Square kilometers x 0.3861 = square miles
Cubic meters/sec x 35.315 = cubic feet/sec
Centimeters x 0.3937 = inches
Kilograms x 2.205 = pounds
Kilograms/square kilometer x 5.711 = Ibs/square mile

-------
    APPENDIX C
TRIBUTARY FLOW DATA

-------
                                   TRIBUTARY FLOW INFORMATION FOR IOWA

LAKE CODE 1903     BLACKHAMK
          SUB-DRAINAGE
TRIBUTARY  AREAIS9 KH)
                                       12/23/75
1903A1
190381
19032Z
              60.3
              13.2
OF LAKE (SO KH) 60.
JAN
O.Ob
0.04
0.01
FEB
0.16
0.12
0.03
MAR
0.57
0.45
0.13
.3

APR
0.
0.
0.
43
34
09

MAY
0.52
0.41
0.11



NORMALIZED FLOWS (CMS)
JUN JUL AUG
0.45
0.35
0.10
0.21
0.16
0.05
0.36
0.28
0.08

SEP
0.19
0.15
0.04

OCT NOV
0.13 0.09
0.10 0.07
0.03 0.02

DEC MEAN
0.07 0.27
0.05 0.21
0.02 0.06
SUMMARY
OTAL
iUM OF
DRAINAGE AREA OF LAKE *
SUB-DRAINAGE AREAS '
60.3
60.3


TOTAL FLOW
TOTAL FLOW
IN «
OUT *
3.24
3.24

     MEAN MONTHLY FLOWS AND DAILY FLOWS(CMS)

TRIBUTARY   MONTH   YEAR    MEAN FLOW  DAY

1903A1
190381
1903ZZ
8
9
10
11
12
1
2
3
4
5
6
7
a
9
10
11
12
1
2
3
4
s
6
7
6
9
10
11
12
1
2
3
4
5
6
1
74
74
74
74
74
75
75
75
75
75
75
75
74
74
74
74
74
75
75
75
75
75
75
75
74
74
74
74
74
75
75
75
75
75
75
75
0.01
0.01
0.01
0.0
0.0
0.0
0.0
0.0
0.62
0.62
0.54
0.24
0.01
0.01
0.01
0.0
0.0
0.0
0.0
0.0
0.51
0.48
0.48
0.21
0.00
0.00
0.00
0.0
0.0
0.0
0.0
0.0
0.14
0.14
0.14
0.06
17
21

2
20
25
22
26
10
12
12
24
17
21

2
20
25
22
26
10
12
12
24












FLOW  DAY
0.01
0.01
0.0
0.0
0.0
0.0
0.0
0.48
0.68
0.45
0.20
0.01
0.01
0.0
0.0
0.0
0.0
0.0
0.37
0.54
0.40
0.17







26
27
27








26
27
27

                  FLOW  DAY
                                    FLOW
                                                                     0.34
                                                                     0.40
                                                                     0.48
                                                                     0.26
                                                                     0.31
                                                                     0.42

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        APPENDIX D





PHYSICAL and CHEMICAL DATA

-------
STORET RETRIEVAL DATE 75/12/23
                                                                  190301
                                                                 42 18 00.0 095 00 45.0
                                                                 BLACK HAWK LAKE
                                                                 19161   IOWA
DATE
FROM
TO
74/04/19
74/07/03
74/09/25
DATE
FROM
TO
74/04/19
74/09/25
TIME DEPTH
OF
DAY FEET
13 45 0000
15 00 0000
09 50 0000
09 50 0002
TIME DEPTH
OF
DAY FEET
13 45 0000
09 50 0000
09 50 0002
00010
WATER
TEMP
CENT
12.7
25.2
15.2
15.2
00665
PHOS-TOT
MG/L P
0.161
0.181
0.197
00300
00
MG/L
9.0
8.6
32217
CHLRPHYL
A
UG/L
50.3
45.7
00077
TRANSP
SECCHI
INCHES
9
14
12
00031
INCDT LT
REMNING
PERCENT
1.0
                                                    00094
                                                  CNDUCTVY
                                                  FIELD
                                                  MICROMHO

                                                       186
                                                       467
                                                       323
                                                       323
11EPALES
3
00400
PH
,. SU
8.60
8.90
8.22
8.23
00410
T ALK
CAC03
MG/L
177
145
145
2111202
0005 FEET DEPTH
00610
NH3-N
TOTAL
MG/L
0.060
0.070
0.070
00625
TOT KJEL
N
MG/L
1.400
1.600
1.600
00630
N02&N03
N-TOTAL
HG/L
2.390
0.060
0.050
00671
PHOS-OIS
ORTHO
MG/L P
0.813
0.022
0.024

-------
STORE! RETRIEVAL DATE 75/12/33
                                                                  190302
                                                                 42 17 24.0 095 01 48.0
                                                                 BLACK HAtfK LAKE
                                                                 19161   I OH A
  DATE   TIME DEPTH  WATER
  FROM    OF          TEMP
   TO    DAY  FEET    CENT

74/04/19 13 55 0000     12.4
74/07/03 14 50 0000     24.5
74/09/25 10 15 0000     14.6
         10 15 0002     14.6
                      00665
  DATE   TIME DEPTH PHOS-TOT
  FROM    OF
   TO    DAY  FEET   MG/L P

74/04/19 13 55 0000    0.168
74/07/03 14 50 0000
74/09/25 10 15 0000    0.189
         10 15 0002    0.198
11EPALES

00300
DO

MG/L

' 8.0
9.0
8.6
32217
CHLRPHYL
A
UG/L
59.3
43.7
49.7

06077 ®@094
TRANSP CNDUCTVY
SECCHI FIELD
INCHES MICROMHO
9 187
15 456
12 321
321
00031
INCDT LT
REMNING
PERCENT
17.0


3
00600
PH

SU
8.60
8.90
8.14
8.14








00410
T ALK
CAC03
MG/L
168

145
148







2111202
0006
00610
NH3-N
TOTAL
MG/L
0.040

0.060
0.070







FEET DEPTH
00625 00630
TOT KJEL N02&N03
N N-TOTAL
MG/L MG/L
1.800 2.150

1.700 0.070
1.600 0.040








00671
PHOS-OSS
ORTHQ
MG/L P
0.012

6.019
0.022







1.0

-------
  APPENDIX E
TRIBUTARY DATA

-------
STORET RETRIEVAL DATE 76/01/27
                                                                  1903A1
                                                                 42 17 30.0 095 00 40.0
                                                                 UNNAMED STREAM
                                                                 19015   SAC CO IA rIMY MP
                                                                 0/BLACKHAWK LAKE
                                                                 BRDG ON RO 2 MI ESE OF LAKE VIEW
                                                                 11EPALES             2111204
                                                                 4                   0000 FEET  DEPTH

DATE
FROM
TO
74/08/17
74/09/21
75/04/10
75/04/26
75/05/12
75/05/27
75/06/12
75/06/27
75/07/24

TIME DEPTH
OF
DAY FEET
15 20
13 30
16 10
19 00
20 00
19 35
20 01
19 50
16 50
00630
N02&N03
N-TOTAL
MG/L
0.136
0.020
0.750
0.010
0.125
0.095
0.540
0.390
0.010
00625
TOT KJEL
N
MG/L
1.900
2.100
2.700
2.800
4.000
1.680
3.700
2.100
1.350
00610
NH3-N
TOTAL
MG/L
0.120
0.020
0.045
0.030
0.045
0.220
0.875
0.540
0.030
00671
PHOS-DIS
ORTHO
MG/L P
0.015
0.020
0.035
0.040
0.020
0.020
0.065
0.095
0.290
00665
PHOS-TOT

MG/L P
0.155
0.180
0.260
0.200
0.180
0.090
0.200
0.140
0.380

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STORET RETRIEVAL DATE 76/01/27
                                                                  1903B1
                                                                 42 17 00.0  095 03 00.0
                                                                 UNNAMED  STREAM
                                                                 19      SAC CO IA HWY MP
                                                                 T/BLACKHAMK LAKE
                                                                 BRDG  ON  RD  1 MI S OF LAKE  VIEW
                                                                 11EPALES            2111204
                                                                 4                  0000 FEET   DEPTH

DATE
FROM
TO
74/08/17
74/09/21
74/10/20
74/11/03
75/04/10
75/04/26
75/05/12
75/05/27
75/06/12
75/06/27
75/07/24

TIME DEPTH
OF
DAY FEET
15 50
14 00
10 18
14 00
15 53
19 10
20 10
19 45
20 10
20 17
17 00
00630
N02&N03
N-TOTAL
MG/L
1.200
0.020
0.024
0.016
9.600
8.700
10.000
10.500
10.500
9.700
1.150
00625
TOT KJEL
N
MG/L
1.600
2.800
1.600
2.000
1.500
1.180
1.250
0.900
1.700
1.200
2.400
00610
NH3-N
TOTAL
MG/L
0.270
0.060
0.185
0.150
0.165
0.165
0.025
0.070
0.100
0.105
0.230
00671
PHOS-DIS
ORTHO
MG/L P
0.280
0.090
0.040
0.045
0.150
0.180
0.005
0.065
0.095
0.090
0.190
00665
PHOS-TOT

MG/L P
0.470
0.420
0.260
0.230
0.290
0.260
0.120
0.130
0.220
0.190
0.500

-------