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
-------
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
-------
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
-------
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.
-------
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-
-------
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.
-------
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.
-------
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
-------
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
-------
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
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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
-------
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
-------
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
------- |