U.S. ENVIRONMENTAL PROTECTION AGENCY
           NATIONAL EUTROPHICATION SURVEY
                    WORKING PAPER SERIES
                                         REPORT
                                          ON
                                     ROCK CREK LAKE
                                      JASPER COUNTY
                                          IOWA
                                      EPA REGION VII
                                   WORKING PAPER No, 504
CORVALLIS ENVIRONMENTAL RESEARCH LABORATORY - CORVALLIS, OREGON
                            and
ENVIRONMENTAL MONITORING & SUPPORT LABORATORY - LAS VEGAS, NEVADA
 699-440

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                                  REPORT
                                    ON
                             ROCK CREK LAKE
                              JASPER COUNTY
                                   IOWA
                              EPA REGION VII
                          WORKING PAPER No,
      WITH THE COOPERATION OF THE
IOWA DEPARTMENT OF ENVIRONMENTAL QUALITY
               AND THE
          IOWA NATIONAL GUARD
              AUGUST, 1376

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                                   CONTENTS

                                                               Page
  Foreword                                                      ii
  List of Iowa Study Lakes                                      iv
  Lake and Drainage Area Map                                     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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                          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)],
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
Darling
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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      ROCK CREEK
         LAKE

— (^Tributary Sampling Site
  XLake Sampling Site
  3 Drainage Area Boundary
           i
           Scale
2 Mi.
                                                                  4150H
              92*54

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                             ROCK CREEK LAKE
                             STORE! NO. 1911

I.  CONCLUSIONS
    A.  Trophic Condition:
            Survey data indicate Rock Creek Lake is eutrophic.   It
        ranked eighth in overall trophic quality when the 15 Iowa
        water bodies sampled in 1974 were compared using a com-
        bination of six parameters*.  Seven of the water bodies
        had less median total phosphorus, none of the others had
        less but one had the same median dissolved phosphorus,  ten
        had less median inorganic nitrogen and mean chlorophyll a_,
        and 11 had greater mean Secchi disc transparency.
            Survey limnologists noted beds of aquatic macrophytes
        along the shore near station 1 in July and an algal  bloom
        at station 1 in September.
    B.  Rate-Limiting Nutrient:
            The algal assay results show that Rock Creek Lake was
        phosphorus limited in April and September.  The lake data
        indicate phosphorus limitation at all  sampling stations
        and times.
    C.  Nutrient Controllability:
            1.  Point sources—There were no known point sources
        impacting Rock Creek Lake during the sampling year.   None-
        theless, the present phosphorus loading of 3.12 g/m2/yr is
* See Appendix A.

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                             2
six times that proposed by Vollenweider (Vollenweider and
Dillon, 1974) as a eutrophic loading (see page 11).
    2.  Non-point sources—The primary source of phosphorus
was Rock Creek which contributed an estimated 64.7% of the
total phosphorus load to the lake during the sampling year.
The minor tributaries and immediate drainage area contributed
an estimated 34.8% of the total load.
    The phosphorus export rate of Rock Creek was a high
77 kg/km2 during the sampling year.  Since no point sources
impact the stream, land-use practices must be the cause of
the high export rate.
    In a study of the Iowa Great Lakes, Bachmann and Jones
(1973) found the variability in the phosphorus loads in
the tributaries was highly correlated with the numbers of
animal units (one animal unit = one beef animal) in the
respective watersheds, and the 1969 Census of Agriculture
(Anonymous, 1973) shows an animal density in the Rock Creek
Lake area similar to that in the Iowa Great Lakes area.
This suggests that a significant reduction in the Rock Creek
phosphorus input may require control of animal wastes.
    Reportedly, many ducks utilize the main portion of Rock
Creek Lake during spring and fall migrations (Anonymous, 1972).
However, waterfowl counts are not made routinely (Harrison, 1976),
and the significance of nutrient contributions of migrating ducks
cannot be determined.

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II.   LAKE AND DRAINAGE BASIN CHARACTERISTICS1"
     A.   Lake Morphometry  :
         1.   Surface area:   2.60 kilometers2.
         2.   Mean depth:   2.7 meters.
         3.   Maximum depth:   6.7 meters.
         4.   Volume:  7.020  x 106 m3.
         5.   Mean hydraulic  retention  time:   143  days.
     B.   Tributary and Outlet:
         (See Appendix C  for flow data)
         1.   Tributaries  -
                                               Drainage        Mean  flow
             Name                              area  (km2)*     (m3/sec)*
             Rock Creek                           67.9           0.36
             Minor tributaries &
              immediate drainage -                36.7           0.21
                         Totals                   104.6           0.57
         2.   Outlet -
             Rock Creek                           107.2**         0.57
     C.   Precipitation***:
         1.   Year of sampling:  88.6 centimeters.
         2.   Mean annual: 87.6 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
      Rock Creek 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 two or more 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 March and September
  visits, a single 18.9-liter depth-integrated sample was composited
  for algal assays.  Also each time, a depth-integrated sample was col-
  lected from each of the stations for chlorophyll a_ analysis.  The
  maximum depths sampled were 4.6 meters at station 1  and 1.5 meters
  at  station 2.
      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 (C)

OISS OXY (MG/U

CNDCTVY (HCROMO)

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)

INORG 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

 11.5  -  12.7    12.0    11.7

 10.4  -  13.8    11.9    11.4

  83.  -  225.    146.    161.

  8.6  -   8.7     8.7     8.7

 136.  -  146.    140.    138.

0.061  - 0.071   0.065   0.06S

0.004  - 0.007   0.005   0.005

2.210  - 2.390   2.314   2.320

0.030  - 0.050   0.038   0.040

0.600  - 1.000   O.U40   0.900

2.250  - 2.420   2.352   2.370

2.980  - 3.320   3.154   3.170

 24.4  -  34.9    29.6    29.6

  0.5  -   0.6     0.5     0.5
                                                        CHEMICAL CHARACTERISTICS FOR ROCK CREEK LAKE
                                                         STORET CODE 1911
                                                                   2ND SAMPLING ( 7/ 3/74)

                                                                         2 SITES
    RANGE

23.6  -  24.8

 6.6  -   7.4

368.  -  455.

 7.8  -   8.0
                   MEAN   MEDIAN

                   24.1    23.7

                    6.9     6.8

                   402.    369.

                    7.9     7.8

**••**  _•*•**»**»••»•••••*••**

•••••o  _*•••••••**•*•••••**•**

******  _••••••••••••••••••••••

******  -•»*«•»*•»«»*••*•*•••*•

*•*•••  .<***•»»»*•*•••**»••*•*

»*•*«*  -••»•••••••••••••••••••

<>•*•••  _»**»•**••**»••••*•••*»

••»»••  -•*•*•••••••*•*•••*•*•*

   4.2  -  18.7    11.4    11.4

   0.2  -   0.3     0.3     0.3
       3RD SAMPLING ( 9/24/74)

             2 SITES

     RANGE        MEAN   MEDIAN

 15.5  -  16.4    16.0    16.3

  7.0  -   8.2     7.7     8.0

 265.  -  337.    321.    333.

  7.8  -   8.0     7.9     7.9

 192.  -  194.    193.    194.

0.056  - 0.073   0.067   0.069

0.008  - 0.013   0.010   0.010

0.280  - 0.310   0.294   0.290

0.240  - 0.260   0.246   0.240

1.000  - 1.600   1.300   1.400

0.520  - 0.550   0.540   0.550

1.310  - 1.880   1.594   1.680

 13.5  -  14.5    14.0    14.0

  0.4  -   1.0     0.7     0.7

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B.  Biological characteristics:

    1.  Phytoplankton -
        Sampling
        Date

        04/19/74
        07/03/74
        09/24/74
    2.   Chlorophyll  a_ -

        Sampling
        Date

        04/19/74
       07/03/74
        09/24/74
Dominant
Genera

1.  Cyclotella sp.
2.  Flagellates
3.  Cryptomonas sp.
4.  Chlamydomonas sp.
5.  Aphanizomenon sp_.
    Other genera

            Total

1.  Cryptomonas sp.
2.  Centric diatoms
3.  Nitzschia sp.
4.  Melosira'sp.
5.  Lepocinclis sp.
    Other genera

            Total

1.  Aphanizomenon sp.
2.  Cryptomonas sp.
3.  Flagellates
4.  Chlamydomonas sp.
5.  Cruci gem'a sp.
    Other genera

            Total
Station
Number

  1
  2

  1
  2

  1
  2
                           Algal  Units
                           per ml	

                            16,387
                               712
                               574
                               122
                                52
                               243

                            18,090

                               502
                               413
                               325
                                59
                                59
                               118
                                                          1,476
                                                          4,451
                           Chlorophyll
                           (ug/D

                               24.4
                               34.9

                                4.2
                               18.7

                               14.5
                               13.5

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C.  Limiting Nutrient Study:

    1.  Autoclaved,  filtered,  and nutrient spiked  -

        a.  April  sample -
        Spike (mg/1)

        Control
        0.050 P
        0.050 P + 1.0 N
        1.0 N
        b.  September sample -
Ortho P
Cone, (mg/1)
Inorganic N    Maximum yield
Cone, (mg/1)   (mg/1-dry wt.)
0.010
0.060
0.060
0.010
2.220
2.220
3.220
3.220
0.2
18.7
16.3
0.2
        Spike (mg/1)

        Control
        0.050 P
        0.050 P  + 1.0 N
        1.0 N
Ortho P
Cone, (mg/1)

   0.015
   0.065
   0.065
   0.015
Inorganic N    Maximum yield
Cone,  (mg/1)   (mg/1-dry wt.)
    0.532
    0.532
    1.532
    1.532
 5.0
17.5
30.0
 4.9
    2.  Discussion -

            The control  yield of the assay alga,  Selenastrum capri-

        cornutum,  indicates that the potential  primary  productivity

        of Rock Creek Lake was low in April  but was  moderately  high

        in September.

            The results  also indicate that Rock Creek Lake was

        phosphorus limited at those times.   Note  that the addition

        of only phosphorus resulted in a  significant increase in

        yield but  no increase in yield occurred with the addition

        of nitrogen only.

            The mean lake  inorganic nitrogen/orthophosphorus ratios

        also indicate phosphorus limitation; i. e,.  the N/P  ratios

        were 54/1  or greater at all sampling stations and times.

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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 and May when two samples  were collected.
 Sampling was begun in August, 1974, and was completed in  May, 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" ("ZZ" of  U.S.G.S.) were esti-
 mated using the nutrient loads at station A-2, in  kg/km2/year,  and
 multiplying by the ZZ area in km2.
     No known point sources impacted Rock Creek Lake  during the  sampling
 year.
 * See Working Paper No. 175.

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        Waste Sources:
        1.  Known domestic -
        Name
        Rock Creek
         State Park
Pop.
Served
            Mean Flow
Treatment   (m3/d)
stab, ponds     ?
        2.  Known industrial - None
        Annual Total Phosphorus Loading - Average Year:
        1.  Inputs -
            Source
                      kg P/
                      yr
            a.  Tributaries (non-point load) -
                Rock Creek                    5,255
            b.  Minor tributaries & immediate
                 drainage (non-point load) -  2,825
            c.  Known municipal STP's -
            d.  Septic tanks -
            e.  Known industrial -
            f.  Direct precipitation** -         45
                        Total                  8,125
        2.  Outputs -
            Lake outlet - Rock Creek          1,450
        3.  Net annual P accumulation - 6,675 kg.
Receiving
Water
no discharge*
                           % of
                           total
                                      64.7

                                      34.8
                                       0.5
                                     100.0
* Ruchti, 1976.
** See Working Paper No. 175.

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                                     10
        Annual Total Nitrogen Loading - Average Year:
        1.  Inputs -
            Source
kg N/
yr
            a.  Tributaries (non-point load) -
                Rock Creek                    58,165
            b.  Minor tributaries & immediate
                 drainage (non-point load) -  31,450
            c.  Known municipal STP's - None
            d.  Septic tanks - None
            e.  Known industrial - None
            f.  Direct precipitation* -        2.805
                        Total                 92,420
        2.  Outputs -
            Lake outlet - Rock Creek          70,375
        3.  Net annual N accumulation - 22,045 kg.
        Non-point Nutrient Export by Subdrainage Area:
        Tributary                             kg P/km2/yr
        Rock Creek                                77
% of
total
                62.9

                34.0
                 3.1
               100.0
               kg N/kiti2/yr
                   857
* 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/mVyr             3.12      2.57        35.5        8.5
    Vollenweider phosphorus loadings
     (g/m2/yr)  based on mean depth and mean
     hydraulic  retention time of Rock Creek  Lake.
        "Dangerous"   (eutrophic loading)                0.52
        "Permissible"  (oligotrophic  loading)           0.26

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                                 12

LITERATURE REVIEWED

Anonymous, 1972.  Rock Creek State Park brochure.  IA Cons.  Comm.,
    Des Moines.

Anonymous, 1973.  1969 Census of Agriculture, vol. 5, part 15.
    U.S. Dept of Commerce, Wash., DC.

Bachmann, R. W., and J. R. Jones, 1973.  Relationship between
    livestock and phosphorus inputs to the Iowa Great Lakes  in
    1971 and 1972.  MS, Dept. Zoo. & Ent., IA St. U., Ames.

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

                  , 1976.  Personal communication (waterfowl numbers
    at Rock Creek Lake).  IA Cons. Comm., Des Moines.

Ruchti, Roger (Park Officer), 1976.  Personal communication (waste
    treatment facilities at Rock Creek State Park).  Kellogg.

Vollenweider, R. A., and P. J. Dillon, 1974.  The application of
    the phosphorus loading concept to eutrophication research.
    Natl. Res. Council of Canada Publ. 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 ACGUAdI

1902  BIG CREEK RESERVOIR

1903  BLACK HAWK LAKE

1904  CLEAR LAKE

1905  LAKE DARLING

1906  LOST ISLAND LAKE

1907  LAKE MACBRIOE

1908  PRAIRIE ROSE LAKE

1909  RATHBUN RESERVOIR

1910  RED ROCK LAKE

1911  ROCK CREEK LAKE

1912  SILVER LAKE

1913  SPIRIT LAKE

1914  VIKING LAKE

19J5  WEST LAKE OKOBOJI
MEOIAN
TOTAL P
0.06?
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
MEOIAN
INORG 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
438.500
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
CMLOP.A
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
MEOIAN
OISS OKThO 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
190?  BIG CREEK RESERVOIR
1903  BLACK HAWK LAKE
1904  CLEAR LAKE
1905  LAKE DARLING
1906  LOST ISLAND LAKE
1907  LAKE M4C8RIDE
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 P
57 (
89 (
7 (
71 (
29 (
21 (
64 <
79 (
43 (
1* «
50 (
0 (
100 (
36 (
89 (
8)
12)
1)
10)
4)
3)
9)
ID
6)
2>
7)
0)
14)
5)
12)
MEDIAN
INOwG 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
CHLORA
93 <
57 (
7 (
36 (
71 (
14 (
50 <
43 <
86 (
64 (
29 t
0 (
79 (
21 (
100 (
13)
8)
1)
5)
10)
2)
7)
6)
12)
9)
4)
0)
11)
3)
14)
15-
MIN DO
100 (
21 I
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 <
11)
7)
3)
8)
6)
2)
8)
8)
12)
0)
13)
1)
13)
4)
4)
INDEX
NO
422
296
110
382
235
32*.
263
375
319
167
314
107
504
250
428

-------
LAKES RANKED BY INDEX NOS.




RANK  LAKE CODE  LAKE NAME               INDEX NC






   1  1913       SPIRIT LAKE                504




   2  1915       WEST LAKE OK080JI          428



   3  1901       LAKE ACOUABI               422



   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
                                                                                          12/23/75
LAKE CODE 1911
                   ROCK CREEK RES.
          SUB-DRAINAGE
TRIBUTARY  AREA(SO KM)
1911A1
1911A2
1911ZZ
107.2
 67.9
 39.4
OF LAKE (SO KH) 107,
JAN
0.28
0.17
0.10
FEB
0.87
0.55
0.32
MAR
1.40
0.89
0.52
.2
APR
0.78
0.50
0.29

MAY
0.91
0.57
0.33




NORMALIZED FLOWS(CMS)
JUN JUL AUG
1.07
0.68
0.39
0.62
0.39
0.23
0.
0.
0.
21
13
08

SEP
0.20
0.13
0.07

OCT NOV
0.21 0.22
0.13 0.14
0.08 0.08

DEC MEAN
0.15 0.57
0.09 0.36
0.05 0.21
SUMMARY
OTAL
;UM OF
DRAINAGE AREA OF LAKE '
SUB-DRAINAGE AREAS =
107.2
107.2


TOTAL
TOTAL
FLOW
FLOW
IN «
OUT =>
6.93
6.93

     MEAN MONTHLY FLOWS AND DAILY FLOWS(CMS)

TRIBUTARY   MONTH   YEAR    MEAN FLOW  DAY

1911A1
1911A2
1911ZZ
8
9
10
11
12
1
2
3
4
S
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
6
7
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
0.23
0.07
0.08
0.28
0.34
0.22
0.16
1.22
0.85
0.48
1.02
0.40
0.16
0.05
0.05
0.21
0.22
0.14
0.10
0.76
0.54
0.31
0.71
0.27
0.09
0.03
0.03
0.12
0.13
0.08
0.06
0.45
0.31
0.18
0.42
0.16
17
14
19
16
13
11
22
16
5
18


17
14
19
16
13
11
22
16
5
18














                                      FLOW  DAY
                                                        FLOW   DAY
                                                                          FLOW
0.18
0.07
0.06
0.27
0.34
.20
.18
.31
.65
.42
0.13
0.05
0.04
0.19
0.22
0.12
0.11
0.20
0.40
0.26








19
25








19
25
                                                                     0.68
                                                                     0.37
                                                                     0.42
                                                                     0.23

-------
        APPENDIX D






PHYSICAL and CHEMICAL DATA

-------
STORET RETRIEVAL DATE 75/13/23
                                                                  191101
                                                                 41  44 27.0 092 51  20.0
                                                                 ROCK CREEK LAKE
                                                                 19       IOWA
                                                                 11EPALES
                                                                 4
 2111202
0020 FEET
DEPTH

DATE
FROM
TO
74/04/19


74/07/03


74/09/24



DATE
FROM
TO
74/04/19


74/07/03

74/09/24





TIME DEPTH
OF
DAY FEET
16 00 0000
16 00 0005
16 00 0015
09 30 0000
09 30 0005
09 30 0012
09 30 0000
09 30 0005
09 30 0014

TIME DEPTH
OF
DAY FEET
16 00 0000
16 00 0005
16 00 0015
09 30 0000
09 30 0004
09 30 0000
09 30 0001
09 30 0005
09 30 0006
09 30 0014
00010
WATER
TEMP
CENT
11.7
11.5
11.5
23.7
23.7
23.6
16.4
16.4
16.3
00665
PHOS-TOT

MG/L P
0.064
0.061
0.071


0.056

0.064

0.072
00300
DO

MG/L

11.4
10.4
6.B
6.6
6.6
7.4
7.0
6.0
32217
CHLRPHYL
A
UG/L
24.4


4.2

14.5




00077
TRANSP
SECCHI
INCHES
25


12


40


00031
INCDT LT
REMNING
PERCENT




1.0

50.0

1.0

                                                  FIELD
194
:TVY
i
IMHO
83
161
225
369
369
368
337
265
337
00400
PH

su
8.70
8.65
8.60
7.80
7.80
7.80
7.85
7.89
7.87
00410
T ALK
CAC03
MG/L
138
137
136



194
194
192
00610
NH3-N
TOTAL
MG/L
0.050
0.040
0.040



0.260
0.240
0.240
00625
TOT KJEL
N
MG/L
1.000
0.800
0.600



1.400
1.000
1.100
00630
N021N03
N- TOTAL
MG/L
2.320
2.210
2.360



0.290
0.310
0.310
00671
PHOS-DIS
ORTHO
MG/L P
0.007
0.005
0.007



0.012
0.009
0.010

-------
STORET RETRIEVAL DATE 75/13/23
                                                                  191102
                                                                 41 46 30.0 092 50
                                                                 ROCK CREEK LAKE
                                                                 19      IOMA
                                                     15.0

DATE
FROM
TO
74/04/19

74/07/03

74/09/24


TIME DEPTH
OF
DAY FEET
16 15 0000
16 15 0005
09 55 0000
09 55 0003
10 00 0000
10 00 0005
00010
WATER
TEMP
CENT
12.7
12.6
24.8
24.7
15.6
15.5
                                00300     00077     00094
                                 00      TRANSP   CNDUCTVY
                                         SECCHI   FIELD
                                MG/L     INCHES   MICROMHO
                                  13.8
                                   7.2
                                   7.4
                                   8.2
                                   8.0
                18

                 8

                14
 91
168
455
450
333
333
11EPALES
4
00400
PH

SU
8.70
8.70
8.00
7.90
8.02
8.03

00410
T ALK
CAC03
MG/L
146
145


193
194
2111202
0007
00610
NH3-N
TOTAL
MG/L
0.030
0.030


0.250
0.240
FEET DEPTH
00625
TOT KJEL
N
MG/L
0.900
0.900


1.600
1.400
00630
N02&N03
N-TOTAL
MG/L
2.270
2.390


0.280
0.280
00671
PHOS-DIS
ORTHO
MG/L P
0.004
0.004


0.006
0.013
                      0066S
  DATE   TIME DEPTH PHOS-TOT
  FROM    OF
   TO    DAY  FEET   MG/L P

74/04/19 16 15 0000    0.065
         16 15 0005    0.066
74/07/03 09 55 0000
74/09/24 10 00 0000    0.073
         10 00 0001
         10 00 0005    0.069
         10 00 0006
  32217     00031
CHLRPHYL  INCDT LT
   A      REMNING
  UG/L    PERCENT

    34.9
    18.7
    13.5
              SO.O

               1.0

-------
  APPENDIX E
TRIBUTARY DATA

-------
STORET RETRIEVAL DATE 76/01/37
                                                                  1911A1
                                                                 41  43 20.0 092 51 00.0
                                                                 HOCK CREEK
                                                                 19125   JASPER CO HWY MP
                                                                 0/ROCK CREEK RESERVOIR
                                                                 BRDG JUST S OF ROCK CREEK STATE PARK
                                                                 HEP ALES             2111204
                                                                 4                   0000 FEET  DEPTH

DATE
FROM
TO
74/08/17
74/09/14
74/10/19
74/11/16
74/12/13
75/01/11
75/02/22
75/03/16
75/04/05
75/04/19
75/05/05
75/05/25

TIME DEPTH
OF
DAY FEET
15 20
14 10
14 00
13 30
12 50
10 15

14 00
14 00
14 30
13 15
13 30
00630
N02&N03
N-TOTAL
MG/L
1.680
0.490
0.240
0.480
0.768
1.160
2.760
1.500
1.570
1.570
1.600
1.500
00625
TOT KJEL
N
MG/L
1.100
1.000
0.600
1.500
1.200
1.700
0.100
1.050
1.850
2.000
1.150
0.700
00610
NH3-N
TOTAL
MG/L
0.095
0.050
0.060
0.270
0.348
0.352
0.085
0.270
0.825
0.720
0.085
0.100
00671
PHOS-DIS
ORTHO
MG/L P
0.010
0.015
0.015
0.015
0.015
0.020
0.023
0.010
0.030
0.030
0.075
0.005
00665
PHOS-TOT

MG/L P
0.045
0.055
0.030
0.070
0.040
0.050
0.040
0.060
0.090
0.100
0.075
0.040

-------
STORET RETRIEVAL DATE 76/01/27
                                                                  1911A2
                                                                 41 49 00.0 092 50 00.0
                                                                 ROCK CREEK
                                                                 19      JASPER CO HWY MP
                                                                 T/ROCK CHEEK RESERVOIR
                                                                 BRDG JUST N OF ROCK CREEK STATE PARK
                                                                 11EPALES             2111204
                                                                 4                   0000 FEET  DEPTH

DATE
FROM
TO
74/08/17
74/09/14
74/10/19
74/11/16
74/12/13
75/01/11
75/02/22
75/03/16
75/04/05
75/04/19
75/05/16
75/05/25

TIME DEPTH
OF
DAY FEET
15 50
13 45
13 47
13 50
13 15
10 35

14 15
14 25
14 55
13 25
13 40
00630
N02&N03
N-TOTAL
MG/L
4.700
2.880
2.640
4.700
4.700
3.680
2.610
2.300
1.600
4.800
4.200
4.200
00625
TOT KJEL
N
MG/L
0.600
0.900
0.700
0.600
0.900
1.900
0.100K
1.180
1.650
3.750
1.050
1.250
00610
NH3-N
TOTAL
MG/L
0.035
0.045
0.090
0.075
0.100
0.432
0.024
0.175
0.780
0.150
0.070
0.030
00671
PHOS-DIS
ORTHO
MG/L P
0.055
0.040
0.035
0.040
0.035
0.065
0.044
0.040
0.030
0.070
0.050
0.045
00665
PHOS-TOT

MG/L P
0.110
0.110
0.080
0.180
0.140
0.300
0.046
0.140
0.310
0.800
0.440
0.260
  K  VALUE  KNOWN  TO  BE
  LESS  THAN  INDICATED

-------