U.S. ENVIRONMENTAL PROTECTION AGENCY
NATIONAL EUTROPHICATION SURVEY
WORKING PAPER SERIES
REPORT
ON
COKATO LAKE
WRIGHT COUNTY
MINNESOTA
PACIFIC NORTHWEST ENVIRONMENTAL RESEARCH LABORATORY
An Associate Laboratory of the
NATIONAL ENVIRONMENTAL RESEARCH CENTER - CORVALLIS, OREGON
and
NATIONAL ENVIRONMENTAL RESEARCH CENTER - LAS VEGAS, NEVADA
frePO 697-O32
-------
REPORT
ON
COKATO LAKE
WRIGHT COUNTY
MINNESOTA
EPA REGION V
WORKING PAPER No, 94
WITH THE COOPERATION OF THE
MINNESOTA POLLUTION CONTROL AGENCY
AND THE
MINNESOTA NATIONAL GUARD
NOVEMBER, 1974
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1
CONTENTS
Page
Foreword ii
List of Minnesota Study Lakes iv, v
Lake and Drainage Area Map vi
Sections
I. Conclusions 1
II. Lake and Drainage Basin Characteristics 3
III. Lake Water Quality Summary 4
IV. Nutrient Loadings 8
V. Literature Reviewed 13
VI. Appendices 14
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11
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 fresh water 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 pointsource discharge reduction and nonpoint
source pollution abatement in lake watersheds.
ANALYTIC APPROACH
The mathematical and statistical procedures selected for the
Surveys 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 [ 5303(e)], water
quality criteria/standards review [ 5303(c)], clean lakes [ 5314(a,b)],
and water quality monitoring [ 5106 and 5305(b)] activities mandated
by the Federal Water Pollution Control Act Amendments of 1972.
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111
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 Nations
fresh water 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 Minnesota Pollution Control
Agency for professional involvement and to the Minnesota National
Guard for conducting the tributary sampling phase of the Survey.
Grant J. Merritt, Director of the Minnesota Pollution Control
Agency, John F. McGuire, Chief, and Joel G. Schilling, Biologist,
of the Section of Surface and Groundwater, Division of Water Quality,
provided invaluable lake documentation and counsel during the course
of the Survey; and the staff of the Section of Municipal Works, Divi-
sion of Water Quality, were most helpful in identifying point sources
and soliciting municipal participation in the Survey.
Major General Chester J. Moeglein, the Adjutant General of
Minnesota, and Project Officer Major Adrian Beltrand, who directed
the volunteer efforts of the Minnesota National Guardsmen, are also
gratefully acknowledged for their assistance to the Survey.
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iv
NATIONAL EUTROPHICATION SURVEY
STUDY LAKES
STATE OF MINNESOTA
LAKE NAME COUNTY
Albert Lea Freeborn
Andrusia Beltrami
Badger Polk
Bartlett Koochiching
Bear Freeborn
Bemidji Beltrami
Big Stearns
Big Stone Big Stone, MN; Roberts,
Grant, SD
Birch Cass
Bi ackduck Bel trami
Blackhoof Crow Wing
Budd Martin
Buffalo Wright
Calhoun Hennepin
Carlos Douglas
Carrigan Wright
Cass Beltrami, Cass
Clearwater Wright, Stearns
Cokato Wright
Cranberry Crow Wing
Darling Douglas
Elbow St. Louis
Embarass St. Louis
Fall Lake
Forest Washington
Green Kandiyohi
Gull Cass
Heron Jackson
Leech Cass
Le 1-lomme Dieu Douglas
Lily Blue Earth
Little Grant
Lost St. Louis
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V
LAKE NAME COUNTY
Madison Blue Earth
Malmedal Pope
Mashkenode St. Louis
McQuade St. Louis
Mi nnetonka Hennepi n
Minnewaska Pope
Mud Itasca
Nest Kandiyohi
Pelican St. Louis
Pepin Goodhue, Wabasha, MN;
Pierce, Pepin, WI
Rabbit Crow Wing
Sakatah Le Sueur
Shagawa St. Louis
Silver McLeod
Six Mile St. Louis
Spring Washington, Dakota
St. Croix Washington, MN; St. Croix,
Pierce, WI
St. Louis Bay St. Louis, MN; Douglas, WI
Superior Bay St. Louis, MN; Douglas, WI
Swan Itasca
Trace Todd
Trout Itasca
Wagonga Kandiyohi
Wailmark Chisago
White Bear Washington
Winona Douglas
Wolf Beltrami, Hubbard
Woodcock Kandiyohi
Zumbro Olmstead, Wabasha
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VI
450 08
450 04
(I
/
j
nfl.
Map Location
45° 00
0
x
I.
COKATO LAKE
Tributary Sampling Site
Lake Sampling Site
Sewa je Treatment Facility
Direct Drainage Area Limits
Indirect Drainage Area
9 ) 1 ?Mi
Scale
I
c J
/
940 14
940 10
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COKATO LAKE
STORET NO. 2719
I. CONCLUSIONS
A. Trophic Condition:
Survey data and the records of others show that Cokato Lake
is eutrophic. Of the 60 Minnesota lakes sampled in the fall
when essentially all were well-mixed, only 3 had poorer overall
water quality based on the parameters measured during the Survey.
Survey limnologists noted a heavy algal bloom in progress in
June, and marked oxygen depression with depth was observed at both
lake stations in June and August, 1972.
Reportedly, severe and toxic blooms of blue-green algae have
occurred in Cokato Lake in the past (Beaton and McGuire, 1969).
B. Rate-Limiting Nutrient:
Because of a significant loss of phosphorus in the algal assay
sample, the results are not reliable.
Lake data indicate nitrogen limitation at all sampling times;
i.e., N/P ratios were 4/1 or less.
C. Nutrient Controllability:
1. Point sources--During the sampling year, Cokato Lake
received a total phosphorus load at a rate about 5 times that
proposed by Vollenweider (in press) as dangerous (i.e., a
eutrophic rate; see page 12). Of that load, the Village of
Cokato contributed about 27%.
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2
On the basis of Survey data, it does not appear that even
complete removal of phosphorus at the Cokato SIP would result
in a satisfactory trophic condition in Cokato Lake, although
the severity and frequency of blue-green algae blooms probably
would be reduced. It is calculated that complete removal of
phosphorus at the STP would reduce the existing loading rate of
23 lbs/acre/yr (2.6 g/m 2 /yr) to about 17 lbs/acre/yr or 1.9
g/rn 2 /yr. This rate would still be over 3½ times the dangerous
rate.
2. Non-point sources-Attention is called to the high mean
non-point phosphorus load of Sucker Creek for the sampling year
(as compared to the unnamed stream and Whitewater Creek--tributary
to Sakatah Lake in LeSeur County; see page 12). This strongly
indicates that there was an unknown point source in the drainage
that contributed over 6,600 lbs of phosphorus during the sampling
year. If such a source exists and phosphorus can be controlled,
it appears that phosphorus control at the Cokato SIP would result
in the enhancement of the trophic condition of Cokato Lake.
With the reservation noted above, in all, it is estimated
that non-point sources contributed about 73% of the total phos-
phorus load reaching Cokato Lake during the sampling year.
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3
II. LAKE AND DRAINAGE BASIN CHARACTERISTICS
A. Lake Morphometryt:
1. Surface area: 544 acres.
2. Mean depth: 25 feet.
3. Maximum depth: 50+ feet.
4. Volume: 13,600 acre/feet.
5. Mean hydraulic retention time: 413 days.
B. Tributary and Outlet:
(See Appendix A for flow data)
1. Tributaries
Name Drainage area* Mean fiow*
Sucker Creek 32.4 mi 2 12.1 cfs
Unnamed Stream (C-i) 5.3 mi 2 1.7 cfs
Minor tributaries & 2
immediate drainage - 6.4 mi 2.8 cfs
Totals 44.1 m1 2 16.6 cfs
2. Outlet -
Sucker Creek 45.0 m1 2 ** 16.6 cfs
C. Precipitation***:
1. Year of sampling: 24.3 inches.
2. Mean annual: 25.9 inches.
1- DNR lake survey map (1964); mean depth by random-dot method.
* Drainage areas are accurate within ±5%; mean daily flows are accurate
within ±10%; and ungaged flows ar accurate within ±10 to 25% for
drainage areas greater than 10 mi.
** Includes area of lake.
See Working Paper No. 1, Survey Methods.
LII3nARY / EPA
Natio o I Environmental Rose iOh Ce
200 S W 35th Street
Corvallis, Oregor 97330
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4
III. LAKE WATER QUALITY SUMMARY
Cokato Lake was sampled three times during the openwater season of
1972 by means of a pontoon-equipped Huey helicopter. Each time, samples
for physical and chemical parameters were collected from two stations on
the lake and from a number of depths at each station (see map, page vi).
During each visit a single depth-integrated (15 feet to surface) sample
was composited from the two stations for phytoplankton identification
and enumeration; and during the last visit, a single five-gallon depth-
integrated sample was composited for algal assays. Also each time, a
depth-integrated sample was collected from each of the stations for
chlorophyll a analyses. The maximum depths sampled were 30 feet at
station 1 and 27 feet at station 2.
The results obtained are presented in full in Appendix B, and the
data for the fall sampling period, when the lake was essentially well
mixed, are summarized below. Note, however, the Secchi disc summary
is based on all values.
For differences in the various parameters at the other sampling
times, refer to Appendix B.
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5
A. Physical and chemical characteristics:
FALL VALUES
(10/26/72)
Parameter Minimum Mean Median Maximum
Temperature (Cent.) 7.5 7.8 7.8 7.9
Dissolved oxygen (mg/i) 9.6 9.7 9.7 9.8
Conductivity (pmhos) 550 553 550 570
pH (units) 8.1 8.2 8.2 8.3
Alkalinity (mg/i) 260 265 260 280
Total P (mg/i) 0.274 0.277 0.275 0.283
Dissolved P (mg/i) 0.261 0.266 0.266 0.270
NO + NO (mg/i) 0.410 0.417 0.420 0.420
Am onia mg/l) 0.770 0.791 0.790 0.830
ALL VALUES
Secchi disc (inches) 28 74 84 108
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6
B. Biological characteristics:
1. Phytoplankton -
Sampling Dominant Number
Date Genera per ml
06/30/72 1. Anabaena 4,991
2. Melosira 127
3. Mallomonas 36
Other genera 18
Total 5,172
08/29/72 1. Cyclotella 30
2. Anabaena 19
3. Cryptomonas 10
4. Pinnularia 8
5. Flagellates 7
Other genera 48
Total 122
10/26/72 1. Flagellates 1,566
2. Chroococcus 837
3. Melosira 837
4. Anabaena 723
5. Cyclotella 512
Other genera 4,475
Total 6,566
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7
2. Chlorophyll a -
(Because of instrumentation problems during the 1972 sampling,
the following values may be in error by plus or minus 20 percent.)
Sampling Station Chlorophyll a
Date Number ( jig/i )
06/30/72 01 17.1
02 32.8
08/29/72 01 0.5
02 0.5
10/26/72 01 7.3
02 5.8
C. Limiting Nutrient Study:
There was a loss of 36% of the dissolved phosphorus in the
algal assay sample from the time of collection to the beginning
of the assay. Consequently, the assay results are not reliable.
The lake data indicate nitrogen limitation at all sampling
times. The N/P ratios were 4/1 or less, and nitrogen limitation
would be expected.
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8
IV. NUTRIENT LOADINGS
(See Appendix C for data)
For the determination of nutrient loadings, from October, 1972,
through September, 1973, the Minnesota National Guard collected monthly
near-surface grab samples from each of the tributary sites indicated on
the map (page vi), except for the high runoff months of April and May,
when two samples were collected, and in January when one site was
omitted because of low flow.
Through an interagency agreement, stream flow estimates for the year
of sampling and a I norma1izedu or average year were provided by the Minne-
sota 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 loadings for unsampled minor
tributaries and immediate drainage (ZZ of U.S.G.S.) were estimated by
using the nutrient loads, in lbs/mi 2 /year, in the unnamed stream at station
C-l and multiplying by the ZZ area in m1 2 .
The operator of the Cokato wastewater treatment plant provided modified
composite effluent samples and corresponding flow data on a monthly basis.
In the following loading tables, the loads attributed to Sucker Creek at
station B-l are those measured minus the Cokato STP loads.
* See Working Paper No. 1.
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9
A. Waste Sources:
1. Known municipal -
Pop. Mean Receiving
Name Served Treatment Flow (mgd) Water
Cokato 1,735* act. sludge 0.264 Sucker Creek
to Cokato Lake
2. Known industrial - None
* 1970 Census.
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10
B. Annual Total Phosphorus Loading - Average Year:
1. Inputs -
lbs P1 % of
Source yr total
a. Tributaries (non-point load)
Sucker Creek 7,620 60.4
Unnamed stream (Ci) 670 5.3
b. Minor tributaries & immediate
drainage (nonpoint load) 800 6.3
c. Known municipal -
Cokato 3,420 27.1
d. Septic tanks* - 20 0.2
e. Known industrial - None -
f. Direct precipitation** - 80 0.6
Total 12,610 100.0
2. Outputs -
Lake outlet - Sucker Creek 7,060
3. Net annual P accumulation - 5,550 pounds
* Estimated 25 dwellings and 1 resort on lakeshore; see Working Paper
No. 1.
** See Working Paper No. 1.
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11
C. Annual Total Nitrogen Loading - Average Year:
1. Inputs -
lbs N I % of
Source yr total
a. Tributaries (non-point load) -
Sucker Creek 80,420 60.5
Unnamed Stream (C-i) 15,500 11.7
b. Minor tributaries & immediate
drainage (non-point load) - 18,720 14.1
c. Known municipal
Cokato 12,120 9.1
d. Septic tanks* - 820 0.6
e. Known industrial - None - -
f. Direct precipitation** - 5,240 3.9
Total 132,820 100.0
2. Outputs -
Lake outlet - Sucker Creek 88,870
3. Net annual N accumulation - 43,950 pounds
* Estimated 25 dwellings and 1 resort on lakeshore; see Working Paper
No. 1.
** See Working Paper No. 1.
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12
D. Mean Annual Non-point Nutrient Export by Subdrainage Area:
Tributary lbs P/mi 2 /yr lbs N/mi 2 /yr
Sucker Creek 235 2,482
Unnamed Stream (C-i) 126 2,924
SAKATAH LAKE:
Whitewater Creek 130 2,960
E. Yearly Loading Rates:
In the following table, the existing phosphorus loading
rates are compared to those proposed by Voilenweider (in press).
Essentially, his dangerous rate is the rate at which the
receiving waters would become eutrophic or remain eutrophic;
his permissible rate is that which would result in the
receiving water remaining oligotrophic or becoming oligo-
trophic if morphometry permitted. A mesotrophic rate would
be considered one between dangerous and permissible.
Total Phosphorus Total Nitrogen
Units Total Accumulated Total Accumulated
1bs/acr /yr 23.2 10.2 244.2 80.8
grams/rn /yr 2.60 1.14 27.4 9.1
Vollenweider loading rates for phosphorus
(g/m 2 Jyr) based on mean depth and mean
hydraulic retention time of Cokato Lake:
Dangerous (eutrophic rate) 0.52
Permissible (oligotrophic rate) 0.26
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13
V. LITERATURE REVIEWED
Anonymous, 1973. Wastewater disposal facilities inventory. MPCA,
Minneapolis.
Beaton, Perry T., and John F. McGuire, 1969. Report on investi-
gation of the water quality of Cokato Lake, Wright County. MPCA,
Minneapolis.
Schilling, Joel, 1974. Personal communication (lake map; industrial
waste sources). MPCA, Minneapolis.
Vollenweider, Richard A., (in press). Input-output models. Schweiz.
A. Hydrol.
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VII. APPENDICES
APPENDIX A
TRIBUTARY FLOW DATA
-------
1P1i-,jTA, Y FLO4 1kFO AT1t)J FOP INNESOIA
10/30/74
LA(F (O W 719
r )4A1C i_ E
TOTAL ) A11IA(, A4 (iF
TOT1 L O-ATNr - OF t Apcr =
0 ).-, t)F S j .t j A 1,A r °F A, =
T ! uT4- Y - 4 0N1- 4 frjA
A . FL ) flAt
rL w flAY
FLOW JAY FLOW
c f, r) . [ to -a
TI 14iJTA Y AQA
F
l()i AL lEE) FLO .S
MAY JUl JUL AUG
27lO I
A . ,)r
-t - -,r
,1.40
1 . O
4?.t O
2 .4J
12.50
14.30
6.90
5.30
5.30
16.60
?71941
1 . .3
3.
. -
1.77
1 -.- 0
.?0
1I.I(i
19. 0
t393
10.50
4.95
3.77
3.95
12.07
?7 19C!
.i,
t,.I
).l
. 6
7 7
674
749
1.09
1.65
0.62
0.42
0.38
1.73
?7 I 77
7 4
7f
4
I
. ..
. 3
1 Ii
4.4 -i
1.97
2.71
1 14
0.81
1 00
2.81
VF. S Mfl .J -iLY Lfl S AIf) JA ILf FL) JS
SEP OCT NOV DEC MEAN
SUMMAPY
.5.00 TOTAL FLOG IN = 198.87
44.94 TOTAL FLO OUT = 198.70
14
19
?7 19AL
I)
72
I1f . r
1.
19.00
I I
2
1.1)
I
27.00
1
7
1.4()
19.00
I
7 1
1 .-41
13
11.0 ,
7
7 )
Q.7, .4
3
II. ) )
-
1
.
5
.4
7
U
0
1 1
7 4
7
74
7)
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74
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7U 3
7. 4
(.,7(
7 f ,0
li
1
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S. ) )
-47.00
4 - .0,J
4 .OU
.4
1l. )
?7 1° - I
10
II
1
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7
3
4
.4
7
P
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7 )
74
F
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c.r
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1(
7
-
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I .0)
11.OO
?.43
3.1)
?.4)
4 0 l
34.0,
J4 j()
3941
i7
5 .)
11.00
50.00
40.00
16.00
-------
F - iHIJi t r Y F LO INFOPMATI(YJ FOP 11NNE OTA
10/30/74
LA
-------
APPENDIX B
PHYSICAL and CHEMICAL DATA
-------
STDPET L) T !FVAI 74f1 /iC
? 11901
45 05 57.0 094 10 1 .5.0
CtJKAT() LA cE
7 M INNFSOTA
I IE AL 5
2111202
0033 FEET DEPTH
r t TF
1 )
7?/t)/ 10
72/ fl /2 ci
7?/ I 0/? -
Tjt t- )f ). 4
rw
PAY r rI
1 .5 η))0
10 2fl ( Ji)
I ) 0 jflltl
C-.,. -i t
(1
O 1C,
3) . 177
044
o O .uo
00410
00630
00610
00665
00666
0AT
TT E
1)F T
.AT k
,V)
T 5r
C .)JCTdY
PH
T ALK
NO ? .NO3
NH3N
Pt- sOSTOT
PHOSDIS
rp
η:
T .D
ECCI- 1 I
FIELD
CACO3
NTOTAL
TOTAL
TO
DAY
FFFT
( F T
G/L
1, .4CHFS
MICROMHO
SO
MG/L
M&/L
MG/L
MG/L P
MG/L P
77/06/3)
19 45 (,000
7 ..
1 -.
30
.50
8.40
173
0.110
0.050
0.03B
0.026
19 45 0015
17.
7..
5?G
8.00
202
0.720
0.170
0.O 53
0.051
19 -.5 0)3)
1(.fl
..
00
7. 0
2 0
0.250
0.950
0.432
0.406
7?/0 /2Q
I ) 0 000)
I0
520
9.10
210
0.400
0.370
0.093
0.058
10 20
l.
i. -
510
E .1O
236
0.400
0.350
0.142
0.136
10 0 0015
.D
30
7. 95
216
0.530
0.450
0.157
0.151
to 7o oo
IS.?
1..
530
7.60
204
0.420
0.700
0.221
0.213
tO 20 )30
11.1
.i,
lO
7.45
254
0.090
0.020
1.120
1.000
72/10/26
10 50 )09
- -.
550
9.10
270
0.420
0.830
0.274
0.269
ID 00 0 )C
f.
550
8.2i)
260
0.410
0.770
0.278
0.268
10 0 0 1
7. -
.7
550
8.20
260
0.410
0.900
0.274
0.264
10 00 0i I
1.
u& ,
550
8.20
260
0.420
0.770
0.274
0.265
17. 1
G.
7. j
J V. LIJE K JO TO - .
-------
ST)PFT ETQ1EVAL >)AT /l)/3O
?7 190?
45 06 15.0 094 09 57.0
COKATO LAKF:
27 MINNESOTA
1IEPALES 2111202
3 0027 FEET DEPTH
DATE
FPOM
TO
TIME 1W T-4
OF
DAY FFET
72/06/10 7) 15 000)
0 15 0015
70 15 0027
72/0 /2Q 10 45 0000
10 45 0034
10 45 0015
10 45 0).?0
10 5 O0 5
72/10/? 10 ?O 0000
10 20 00D4
10 20 0015
10 20 0074
3 > )I0
01>) )
00077
00094
00400
00410
00630
00610
00665
00666
, >T P
0)
T AtSP
CNDIJCTVY
PH
T ALK
NO2&903
NH3N
Pt-iOSTOT
PHOSDIS
TF .ic
SLCCHI
F IFLO
CACO3
NTOTAL
TOTAL
C JT
i( )/L
1 >C >-4FS
MICMOMI-4O
SU
MG/L
MG/L
MG/L
MG/L P
MG/L P
425
530
600
510
505
535
535
600
550
550
550
570
8.40
7.80
7.10
8.10
8.10
7.91
7.75
7. S
8.30
8.30
8.30
R.30
166
206
238
188
210
226
224
216
280
270
260
260
0.060
0.900
0.710
0.390
0.400
0.480
0.490
0.110
0.420
0.420
0.420
0.420
0.050
0.220
0.680
0.380
0.370
0.420
0.560
0.025
0.790
0.780
0.800
0.790
0.042
0.065
0.241
0.152
0.147
0.105
0.200
0.258
0.276
0.283
0.282
0.275
0.024
0.061
0.237
0.079
0.075
0.089
0.187
0.223
0.266
0.270
0.266
0.261
2 ,
16.0
?
17.)
4 2
11.
0.3
lOs I
2p . .
7.0
1 l >. >
S.?
17.
1.6
14.6
0.
7. >
7.7
7.5
12 ,17
CkL- - H YL
a
O / L
OATE
TO
7 2/05/ ID
72/t )R/2
7?/ I0/?(
T1 > E PF2T ,-4
OF
OAY FEET
0 1 5 000)
In 45 )OC)
10 0 0030
l. QJ
0
J V LL1I r(! 4O4J 10 - II EP 0
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APPENDIX C
TRIBUTARY and WASTEWATER
TREATMENT PLANT DATA
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ST - T FTP! #AL ) F 74/11/ J
?719A1 I.52719A1
+5 07 00.4) 09 iO.0
UNJAMLti OUTLET LK/J FK CROW LVE
iS COKATO
O/COKAT() LAKE
XIV, NE CO NE- OF LK 3 Mj NNE OF COKATO
flFALES 2111204
G00( FEET DEPTH
0 -I0 00671
BA f TI rW )T r- O .NOJ Tu I FL N- 3- \ - -OSDJS PHi TOT
OF iTOTAL N TOTAL OPTHO
T I) :)AY F,RT 1 /L 1 /l i /L MC,/L P
7?/1U/1 16 . ).6- 1. 1. /- I3 7 0.0
7?/Il/I Ok 1 ).76.) ).?10
77/12/02 f ) .7- i .46 0.71) 0.?ifl
1.1 0.160 0. So
73/0?/03 H 0 I.-- 1.S0 .1.147 O.1P9
73/01/10 0 1.+ 3.600 0.610 c. 410
71/fl1.e/O7 fl 0 I .)) 2 . )0) i.070 0 160 ( .?l0
71/ /1- u I.lut ?.00 ).07(. 0.fl
71/ ,/07 ) )LJ 1. 7) u.1?0 0.050 0.100
71/CS/1- O 10 1.S 0 0.ll O 0.OS? 0.100
73/06/02 (ik 4η 0.62) l. +00 0.050 0.15C
73/07/15 0 ..Cl1 1. °u (.130 0.031
71/CR/76 0F 25 0.0 - 1. J U.-r () 3.Il
73/0-/16 0 15 0.0-- 1. -J .L. OG 0.1 0.250
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STOQET ETPTFVAL DATE 74/19/30
7 71 9 r11 LS2? 19B1
4S 05 30.0 094 10 00.0
SUCKER CREEK
27 15 COI
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T) F I ETP( VA )AT 7 ./1,/ 4()
LS271 R?
45 O . 30.1) (Jq4 10 30.0
5 Crft CREE c
-i COKATU
J/COP(AT() LAKE
uS 1? X1 OF COcATO AI OVSW
11 ALES 2111204
4 0000 FEET DEPTr4
01 71 00f 5
I! T j [ )f )J .- J)7 (i Tfl I KJ L r1 N D1S - O Ii)T
N TOT L CPT-iO
T I) r y r - r jr,,I /1 MG/L
77/10/i 1 1 - . ) 2.YV) 0. 210
7?/11/1 17 0 ). 1 ) U.(V0 c.15)
7?/17/1) 0 In ( . 9 ) ). 04 -i 0.16)
7 / I/3 - .5 1.7-) .F I0 0 r 1 1.17)
71/O?/0 1)7 45 . 1. 1 O.70(i C. I -e O.1 ti
7 /O3/l0 fl7 IC I.- 4 . .(( I.7 f, 0.11 5
71/04/0? nO . -1) 1. - 0.) u.f 0 0.1?)
. & 0 u. 1 9 (J JO 1 4 0.140
71/r)5/O ) 14A ,I 0.075 0.145
71/t)5/i- )fl 1 c ) L.C1° ).0 - 0. .00
71/UE,/07 uP PG u.7-O ?.Ufl lI 0.c,94 o.ic u o.3 o
71/ui/I- 04 IS 1. .i 1. ?0 ).?70 0.357 0.540
71/) - /7, P7 65 i. -S 0.7 O P 3.?30 0.19( 0.4 0
7 1/0 - 1 )/i - 1.01 c 1. S ).0?f P.SV- 0.91,
K V LU-
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STORET ETRIEVAL r)ATE 7/I0/30
2719C1 LS27I9C I
45 07 00.0 094 11 00.0
UNNAMED T IB TO L( FkOM NW
27 1 COKATO
T/COKATO LAP E
iNG AT NW CORNER OF LPc
I1EPALES 2111204
4 0000 FEET DEPTH
0C630 OG#D25 00610 00671 0 ( 665
TF T1I.1 flF T I iu2 .NO TOT KJEL NH3N PHOSPIS PHOSTOT
F OM OF N-TOTAL N TOTAL OPTHO
TO (JAY FEET 1G/L MG/L MG/L P MG/I P
7?/i0/ 14 16 00 7 .3C 0 3.?O ) 0.]60 0.100 0.273
72/11/11 OR 75 1.170 ?.000 0.015 0.058 0.105
7?/1 ?/O, 08 55 1.900 3.189 0.0 6 0.130
73/02/03 08 40 1.460 1.700 0.320 0.06 0.180
71/03/IC) 07 40 4.900 .60 0.60 0.410
73/0/02 CR 40 3. O Oli 3.120 0.115 0.046 0.145
71/04/1 . 10 15 7.500 4.600 0.140 0.04? 0.185
71/05/0? 0° 10 7.900 ?.400 t). 052 0.048 0.097
71/0S/IQ OM 65 1.160 1.470 0.080 0.048 0.110
73/06/02 09 flfl 3.130 RQ0 0.160 0.120 0.250
71/07/IS 09 10 0.790 1.?00 0.65 0.085 0.135
71/O /?6 08 40 0.720 1. 00 C ). 15 0.079 0.370
71/09/16 0° 00 0.470 1.680 0.315 0.120 0.230
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STOOFT 0ET iEVAI fl T 74/lt/10
oj ,30 00 5 00 10 0fl67 1
271951 A 5271951 P001735
45 05 00.0 001 10 30.0
C OK A TO
27 N COKATO
T/COKATO LAKE
SUCKER CREEK
1IEPALES 2141204
0000 FEET DEPTH
006 5 50051 50051
OATC
TTE
1)F9T -l
NO7 ,NO1
TOT K JEL
NH3N
Pi -inSDIS
Pi-IOSTOT
FLOW
CONDUIT
OF
N-T )TAL
N
TUTAL
O THO
RATE
FLOwMGD
TO
JAY
F T
1G/1
- G/L
MG/L
MG/L P
M(/L P
INST MGD
MONTHLY
73/01/17
II 00
C (T)
I .0j)
0.750
0.140
3.900
5.200
0.234
0.215
73/01/17
13
00
71/O?/N
II
00
CP(T)
I .L.O0
I..000
3.000
4.200
5.500
0.191
0.207
73/0?/N
11 00
73/03/15
11
00
C (T J
13.OO
1.300
2.100
3.400
0.400
0.270
73/03/N
13 00
71/0 /1
11 JO
CP(T)
7 .80j
10.500
0. 0O
7.200
?.900
0.264
0.352
71/O4/1
11 00
73/05/10
Ii 00
CP(T)
10.50)
0.770
2.400
3.300
0.252
0.295
71/05/1°
13 )0
71/05/1°
11 00
CP(r)
- .5Ct)
13.010
3.054
3.200
..000
0.317
0.309
71/06/1
13 CO
71/07/10
11 00
CP(T)
0. hJ
I?.fl00
2.200
3.570
..500
0.185
0.222
71/07/1°
13 00
71/0 I?1
II 00
CP(T)
0.370
4.100
0.0 ?
4.370
4.550
0.206
0.201
73/00/2 1
13 flO
71/09/10
11 00
CP(T)
1.0)0
4. )00
0.0 S
4.500
4. 00
0.190
0.220
71/09/19
13 00
71/13/1°
11 flO
CP(T)
.70 )
2.500
0.160
1.H00
1.950
0.372
0.319
71/10/1°
13 (JO
71/11/10
II 00
CP(T)
N.SflU
II.c03
1. 00
2.500
6.500
0.223
0.262
73/ 1 1/19
13 liD
71/l?/1
11 00
CP(T)
1.000
.7oo
0.250
.000
5.600
0.244
0.294
71/12/1°
Ii 00
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7i/ )/I4 II O
C (1)
7 4 fA)/1
?71951 t S?71951
45 05 00.0 0 3 10 30.0
COKATO
?7 IS CO
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