U.S. ENVIRONMENTAL PROTECTION AGENCY
NATIONAL EUTROPHICATION SURVEY
WORKING PAPER SERIES
REPORT
ON
WOODCOCK LAKE
MNDIYOHI COUNTY
MINNESOTA
REGION V
WORKING PAPER No,
PACIFIC NORTHWEST ENVIRONMENTAL RESEARCH LABORATORY
An Associate Laboratory of the
NATIONAL ENVIRONMENTAL RESEARCH CENTER - CORVALLIS, OREGON
and
NATIONAL ENVIRONMENTAL RESEARCH CENTER - LAS VEGAS, NEVADA
•&GPO 697.032
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REPORT
ON
WOODCOCK LAIC
WNDIYOHI COUNTY
MINNESOTA
EPA REGION V
WORKING PAPER No, M
WITH THE COOPERATION OF THE
MINNESOTA POLLUTION CONTROL AGENCY
AND THE
MINNESOTA NATIONAL GUARD
JULY, 1975
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1
CONTENTS
Page
Foreword ii
List of Minnesota Study Lakes iv, v
Lake and Drainage Area Map vi
Sections
I. Introduction 1
II. Conclusions 1
III. Lake Characteristics 3
IV. Lake Water Quality Summary 4
V. Literature Reviewed 7
VI. Appendices 8
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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 fresh water lakes and
reservoirs.
OBJECTI VES
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 [ 3O3(e)], water
quality criteria/standards review [ 3O3(c)], clean lakes [ 3l4(a,b)],
and water quality monitoring [ 1O6 and §305(b)] activities mandated
by the Federal Water Pollution Control Act Amendments of 1972.
* The lake discussed in this report was included in the National
Eutrophication Survey as a water body of interest to the Minnesota
Pollution Control Agency. Tributaries were not sampled, and this
report relates only to the data obtained from lake sampling.
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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 Nation’s
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 Kandlyohi
Gull Cass
Heron Jackson
Leech Cass
Le Homme 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
Minnetonka Hennepin
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
Walimark Chisago
White Bear Washington
Winona Douglas
Wolf Beltrami, Hubbard
Woodcock Kandiyohi
Zumbro Olmstead, Wabasha
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--
: ‘- -
Q
_- 4. .
•
-: -ç
\ ‘ INN.
Map Location
—
-:-
•4514’30
— 4514’OO”
WOODCOCK LAKE
X Lake Sampling Site
Sewage Treatment Plant
0 1/2 Mi.
I _J
Scale
94.59’
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WOODCOCK LAKE
STORET NO. 27A3
I. INTRODUCTION
Woodcock Lake was included in the National Eutrophication Survey
as a water body of interest to the Minnesota Pollution Control Agency.
The trickling filter wastewater treatment plant serving the Village of
Spicer discharges directly to the lake*, but only two effluent samples
were provided for Survey analyses (Appendix B). Tributaries were not
sampled, and other nutrient sources were not evaluated. Therefore,
this report relates only to the lake sampling data.
II. CONCLUSIONS
A. Trophic Condition:
Survey data indicate Woodcock Lake is hypereutrophic. Of
the 60 Minnesota lakes sampled in the fall when essentially all
were well-mixed, 53 had less mean total phosphorus, 53 had less
mean dissolved phosphorus, and 45 had less mean inorganic nitro-
gen. Of the 80 Minnesota lakes sampled, 66 had less mean
chlorophyll a, and 62 had greater mean Secchi disc transparency.
Dissolved oxygen was nearly depleted at 10 feet in July and August,
1972.
* Anonymous, 1974.
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2
Survey limnologists noted the lake was very turbid and
observed algal blooms in progress on all sampling occasions
with a very heavy bloom in August. Blue-green algae were
dominant in all phytoplankton samples.
B. Rate-Limiting Nutrient:
A 25% loss of dissolved phosphorus and a 22% gain of
inorganic nitrogen occurred in the algal assay sample between
the time of collection and the beginning of the assay, and the
results are not representative of conditions in the lake at
the time the sample was taken (10/25/72).
The lake data indicate nitrogen limitation at all sampling
times; i.e., N/P ratios were 1/1 or less, and nitrogen limitation
would be expected.
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3
III. LAKE CHARACTERISTICS
A. Morphometry*:
1. Surface area: 125 acres.
2. Mean depth: 2.5 feet.
3. Maximum depth: 8 feet.
4. Volume: 312 acre—feet.
B. Precipitation**:
1. Year of sampling: 27.0 inches.
2. Mean annual : 24.5 inches.
* MN Dept. of Conservation waterfowl and muskrat habitat survey map (1952).
** See Working Paper No. 1, “Survey Methods, 1972”.
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4
IV. LAKE WATER QUALITY SUMMARY
Woodcock Lake was sampled three times during the open-water season
of 1972 by means of a pontoon-equipped Huey helicopter. Each time,
samples for physical and chemical parameters were collected from a
number of depths at a single station on the lake (see map, page vi).
During each visit, a single depth-integrated (near bottom to surface)
sample was collected for phytoplankton identification and enumeration,
and a similar sample was collected for chlorophyll a analysis. During
the last visit, a single five-gallon depth-integrated sample was taken
for algal assays. The maximum depth sampled was 11 feet.
The results obtained are presented in full in Appendix A, and the
data for the fall sampling period, when the lake essentially was well-
mixed, are summarized in the following table. 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 A.
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A. Physical and chemical characteristics:
Parameter Minimum
Temperature (Cent.)
Dissolved oxygen (mg/1)
Conductivity (ymhos)
pH (units)
Alkalinity (mg/1)
Total P (mg/1)
Dissolved P (mg/1)
NC-2 + NCh (mg/1)
Ammonia Img/1)
FALL VALUES
(10/25/72)
Mean Median
Maximum
5.3
9.3
490
9.1
220
0.830
0.670
0.290
0.390
5.3
11.4
493
9.1
230
0.903
0.677
0.293
0.403
5.3
11.4
490
9.1
230
0.870
0.680
0.290
0.390
5.4
13.6
500
9.1
240
1.010
0.680
0.300
0.430
ALL VALUES
Secchi disc (inches)
12
15
14
18
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6
B. Biological characteristics:
1. Phytoplankton -
Sampling Dominant Number
Date Genera per ml
07/02/72 1. Microcystis 16,396
2. Merismopedia 8.198
3. Cyclotella 5,766
4. Scenedesmus 3,243
5. Anabaena 991
Other genera 2,793
Total 37,387
08/31/72 1. Aphanocapsa 30,374
2. Microcystis 21 ,334
3. Merismopedia 13,018
4. Lyrigbya 4,339
5. Anabaena 1,446
Other genera 2,893
Total 73,404
10/25/72 1. Anabaena 4,586
2. Chroococcus 3,834
3. Dinobryon 2,481
4. Merismopedia 2,481
5. Cyclindrocystis 2,256
Other genera 6,994
Total 22,632
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 ( pg/i )
07/02/72 01 54.3
08/31/72 01 56.5
10/25/72 01 115.5
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7
V. LITERATURE REVIEWED
Anonymous, 1974. Wastewater disposal facilities inventory. MPCA,
Minneapolis.
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VI. APPENDICES
APPENDIX A
PHYSICAL and CHEMICAL DATA
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STOPET ETR1I-VAL •)ATE 7 ./1O/i0
TA3Oj
45 14 3 .0 094 Sb 57.0
OOOCOCtc LAKE
27 MP’INVSOTA
1 IFPALES
3
2111202
0010 FEET DEPTH
DATE
TO
77/0 7/07
72/08/ 31
72/ I /?5
IIMF )c’1l-
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DAY FFT
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14 70 0000
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TO
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l
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MG/L
MG/L
MG/L P
MG/L P
72/07/0?
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0.848
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0.040
0.640
1.030
0.512
7 7/ OR/ il
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9.05
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0.160
0.220
1.040
0.650
14 40 0004
‘0.5
.9
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9.10
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0.250
0.220
1.000
0.625
1’. 40 0007
‘0.3
.0
465
9.05
244
0.190
0.020
0.965
0.565
14 40 0011
‘0.1
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470
9.00
236
0.220
0.330
1.020
0.680
77/10/24
14 ‘0 0000
1
500
9.10
240
0.300
0.390
0.870
0.670
14 70 0004
5 4
490
9.10
220
0.290
0.390
0.830
0.680
14 20 0011
5.1
1.5
690
9.10
230
0.290
0.430
1.010
0.680
J VALUF rcNOWN TO - F IJ F9PO
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APPENDIX B
WASTEWATER TREAThENT PLANT DATA
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cTOPET ETR1EVAt I )AT -fL.,I1r)/ ft)
?TA)S1 TF274351 P000586
4S 14 00.0 094 57 00.0
S? ICFR
27 15 ATWaTER
O/ )ODCOCK LAI(L
OOOCOCK LAKE
IIEPALES 2141204
4 0000 FEET DEPTH
O0’- 5 iJ( 10 00671 00665 50051 50053
DATF T E E T- O’ .NP Ti)! KJ L N 1 —N PHOS—OI PHO5—TOT FLOW CONDUIT
FROM OF i-TflTt iL TOTAL uRT -4O RATE FLOw—Mc,D
T ) ‘)i Y FFEr “ /L ‘4 /L H(,/L M1,/L M(,/L ‘ INST MGfl MONTHLY
71/02/09 13 10
C (T) 1. ’t1 1O. ’)u 1.2€’; 7.60’) 3.800 0.075
7 /O7/O 11 30
71/J7/2 10 00
CP(T)— ‘ 1.00t 4.5UI 5.400 7.200
7 1 / 0 7/p’-’ 13
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