-------
REPORT
ON
OBOi/LAKE
ST, LOUIS COUIHY
MINNESOTA
LPA REGION V
WORKING PAPER No, 97
WlTH THE COOPERATION OF THE
MINNESOTA POLLUTION CONTROL AGENCY
AND THE
MINNESOTA NATIONAL GUARD
DECEMBER, 1974
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1
CONTENTS
Pa e
Foreword ii
List of Minnesota Study Lakes iv, v
Lake and Drainage Area Map vi
Sections
I. Conclusions i
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 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 [ lO6 and §305(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 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
Blackduck Beltrami
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 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
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 ficLeod
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 Kandlyohi
Walimark Chisago
White Bear Washington
Winona Douglas
Wolf Beltrami, Hubbard
Woodcock Kandiyohi
Zumbro Olmstead, Wabasha
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Map Location
Minnesota
ELBOW LAKE
Tributary Sampling Site
X. Lake
Sewage Treatment Facility
Sampling Site
Iron
Punct ion
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ELBOW LAKE
STORET NO. 2725
I. CONCLUSIONS
A. Trophic Condition:
Survey data show that Elbow Lake is eutrophic. Of the 60
Minnesota lakes sampled in the fall when essentially all were
well-mixed, only three had more mean total phosphorus, only
two had more mean dissolved phosphorus, and only two had more
mean inorganic nitrogen. Of the 80 Minnesota lakes sampled,
18 had less mean chlorophyll a, and 17 had greater Secchi disc
transparency.
Survey limnologists noted an intensive bloom of algae mat-
ting the lake surface during the September sampling.
B. Rate—Limiting Nutrient:
The algal assay results show that Elbow Lake was nitrogen
limited at the time the assay sample was collected. The lake
data indicate nitrogen limitation at the other sampling times
as well (N/P ratios were less than 2/1).
C. Nutrient Controllability:
1. Point sources—-During the sampling year, Elbow Lake received
a total phosphorus load at a rate in excess of that proposed by
Vollenweider (in press) as “dangerous”; i.e., a eutrophic rate (see
page 12). Of this load, it is estimated that the City of Eveleth
contributed over 98%.
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2
It is calculated that complete removal of phosphorus from
the Eveleth effluent would reduce the phosphorus load to 1.2
lbs P/acre/yr or 0.14 g/m 2 /yr which is less than an oligotrophic
rate. If this degree of reduction can be achieved, the trophic
condition of Elbow Lake should be significantly improved.
2. Non-point sources--Non-point sources are estimated to
have contributed less than 2% of the total phosphorus load
reaching Elbow Lake during the sampling year.
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II. LAKE AND DRAINAGE BASIN CHARACTERISTICS
A. Lake Morphometry :
1. Surface area: 171 acres.
2. Mean depth: 10.3 feet.
3. Maximum depth: 20 feet.
4. Volume: 1,761 acre/feet.
5. Mean hydraulic retention time: 296 days.
B. Tributary and Outlet:
(See Appendix A for flow data)
1. Tributaries -
Name Drainage area* Mean flow*
Unnamed Creek (A-l) 4.6 mi2 2.2 cfs
Minor tributaries & 2
immediate drainage - 1.4 mi 0.8 cfs
2
Totals 6.0 mi 3.0 cfs
2. Outlet -
Elbow Creek 6.3 mi2** 3.0 cfs
C. Precipitation***:
1. Year of sampling: 28.0 inches.
2. Mean annual: 26.9 inches.
t DNR survey map (1968); mean depth by random dot method.
* Drainage areas are accurate within ±5%; mean daily flows are accurate
within ±10%; and unqaged flows are accurate within ±10 to 25% for
drainage areas greater than 10 mi2.
** Includes area of lake.
*** See Working Paper No. 1, "Survey Methods".
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4
III. LAKE WATER QUALITY SUM 1ARY
Elbow 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 one station on
the lake and from a number of depths (see map, page vi). During each
visit, a single depth-integrated (near bottom to surface) sample was
collected for phytoplankton identification and enumeration; and during
the last visit, a single five-gallon depth-integrated sample was collected
for algal assays. Also each time, a depth-integrated sample was collected
for chlorophyll a analysis. The maximum depth sampled was 9 feet.
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
(10/19/72)
Parameter Minimum Mean Median Maximum
Temperature (Cent.) 3.8 4.4 4.4 5.1
Dissolved oxygen (mg/i) 7.3 7.3 7.3 7.4
Conductivity (pmhos) 300 300 300 300
pH (units) 7.5 7.5 7.5 7.5
Alkalinity (mg/i) 87 87 87 88
Total P (mg/i) 1.320 1.347 1.340 1.380
Dissolved P (mg/i) 1.260 1.267 1.260 1.280
NO + NO (mg/i) 0.280 0.303 0.310 0.320
Ani onia mg/i) 1.740 1.753 1.750 1.770
ALL VALUES
Secchi disc (inches) 57 75 72 96
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6
B. Biological characteristics:
1. Phytoplankton —
Sampling Dominant Number
Date Genera per ml
07/08/72 1. Anabaena 3,960
2. Schroederia 470
3. Chroococcus 54
4. Mallomonas 54
5. Flagellates 36
Other genera -
Total 4,574
09/09/72 1. Anabaena 1 ,733
2. Dinobryon 30
3. Melosira 15
4. Navicula 8
5. Epithemia 8
Other genera 45
Total 1 ,839
10/19/72 1. Flagellates 1,601
2. Fragilaria 565
3. Anabaena 527
4. Melosira 490
5. Aphanothece 264
Other genera 1,186
Total 4,633
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7
Maximum yield
( mg/l-dry wt. )
47.6
40.6
41.1
45.2
54.5
286.4
269.5
C. Limi
1.
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/l )
07/08/72 01 22.4
09/09/72 01 3.6
10/19/72 01 2.9
ting Nutrient Study:
Autoclaved, filtered, and nutrient spiked -
Ortho P Inorganic N
Spike (mg/l) Conc. (mg/l) Conc.( ijj/l ) ____________
Control 1.100 1.490
0.005 P 1.105 1.490
0.010 P 1.110 1.490
0.020 P 1.120 1.490
0.050 P 1.150 1.490
0.050 P + 10.0 N 1.150 11.490
10.0 N 1.100 11.490
2. Discussion -
The control yield of the assay alga, Selenastrum capri-
cornutum , indicates that the potential primary productivity
of Elbow Lake was very high at the time the sample was col-
lected. The lack of significant increases in yields with
increased levels of ortho-P and the great increase in yield
over the control with the addition of only nitrogen shows
that the lake was strongly nitrogen limited.
The field data also indicate that the lake was nitrogen
limited. Nitrogen to phosphorus ratios were less than 7 to
1 during the three samplings.
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8
IV. NUTRIENT LOADINGS
(See Appendix C for data)
For the determination of nutrient loadings, the Minnesota National
Guard collected monthly near-surface grab samples from each of the tribu-
tary sites indicated on the map (page vi), except for the high runoff
months of May and August when two samples were collected. Sampling was
begun in October, 1972, and was completed in September, 1973.
Through an interagency agreement, stream flow estimates for the year
of sampling and a “normalized” or average year were provided by the
Minnesota District Office of the U.S. Geological Survey for the tribu-
tary sites nearest the lake.
The phosphorus load estimated for the City of Eveleth was slightly
higher than the phosphorus load calculated at station A-i. Therefore,
the background nutrient loads for station A-i were estimated by using
the means of the nutrient loads, in lbs/m1 2 /year, at station B-i of
nearby Mashkenode Lake and multiplying the means by the station A-i area
in mi 2 . The nutrient loads for the outlet were calculated using mean
annual concentrations and mean annual flows at station B-i.
Nutrient loadings for unsampled “minor tributaries and immediate
drainage” (“ZZ” of U.S.G.S.) were estimated by using the means of the
nutrient loads, in ibs/mi 2 /year, at station B-i of Mashkenode Lake and
multiplying the means by the ZZ area in mi 2 .
Nutrient loads from the City of Eveleth were estimated at 2.5 lbs
P and 7.5 lbs N/capita/year.
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9
A. Waste Sources:
1. Known municipal* -
Pop. Mean Receiving
Name Served Treatment Flow (mgd) Water
Eveleth 4,721 act. sludge O.472** Unnamed Creek
to Elbow Lake
2. Known industrial - None
* Anonymous, 1974.
** Estimated at 100 gal/capita/day.
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10
B.’Annual Total’ Phosphorus Loading - Average Year:
1. Inputs -
lbs P/ % of
: Source yr - total
a . Tributaries (non-point load)
‘ :UnnamedCreek (A—i) 140 1.2
:b:. Minor tributaries & immediate
drainage (non-point load) - 40 0.3
c. Known municipal SIP’s -
Eveleth 11,800 98.3
d. Septic tanks - Unknown
e. Known industrial - None -
f. Direct precipitation* - 30 0.2
Total 12,010 100.0
2. Outputs -
- Lake outlet - Elbow Creek 4,030
3. Net annual P accumulation - 7,980 pounds
* See Working Paper No. 1.
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11
C. Annual Total Nitrogen Loading - Average Year:
1 . Inputs -
lbs N/ % of
Source yr total
a. Tributaries (non-point load) -
Unnamed Creek (A-i) 5,770 12.9
b. Minor tributaries & immediate
drainage (non-point load) - 1,760 3.9
c. Known municipal STP t s -
Eveleth 35,410 79.4
d. Septic tanks - Unknown
e. Known industrial - None -
f. Direct precipitation* - 1,650 3.8
Total 44,590 100.0
2. Outputs -
Lake outlet - Elbow Creek 13,880
3. Net annual N accumulation - 30,710 pounds
* See Working Paper No. 1.
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12
0. Yearly Loading Rates:
In the following table, the existing phosphorus loading
rates are compared to those proposed by Vollenweider (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
lbs/acre/yr 70.2 46.7 278.3 194.4
gramsfm’/yr 7.87 5.23 31 .2 21 .8
Vollenweider loading rates for phosphorus
(g/m 2 /yr) based on mean depth and mean
hydraulic retention time of Elbow Lake:
“Dangerous” (eutrophic rate) 0.40
“Permissible” (oligotrophic rate) 0.20
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13
V. LITERATURE REVIEWED
Anonymous, 1974. Wastewater disposal facilities inventory. MPCA,
Minneapolis.
Schilling, Joel, 1974. Personal communication (lake map). MPCA,
Minneapolis.
Vollenweider, Richard A. (in press). Input-output models. Schweiz.
A. Hydrol.
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VII. APPENDICES
APPENDIX A
TRIBUTARY FLOW DATA
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T 7JHtJTAPY FLOW lNF0 AT1ON F0 MINNESOTA 10/30/74
LA(E r0I)E 77 ’ S CL lO LAr E
TOTAL nOATNAGE A)FA OF LAKI 6.10
SUB—DPAINA Ot NORMALIZED FLOWS
TPIPUTADY AQUA JAN Ff i MA APH MAY JUN JUL AUG SEP OCT NOV DEC MEAN
4.55 3.11 0.11 0.54 11.00 5.39 3.03 2.23 0.6? 0.86 1.30 0.80 0.22 2.18
?7?58l 4•3 0 0.15 0.15 0.66 15.30 1.58 4.17 3.14 0.91 1.20 1.90 1.19 0.30 3.05
272577 1.75 O. )4 0.0? 0.16 3.94 2.06 1.18 0.87 0.24 0.36 0.52 0.30 0.08 0.81
SUMMARY
rUrAL DNAINAC,E AREA OF LAKE = TOTAL FLOW IN = 35.98
SUM OF SUH-C A1NAOE APEAS = TOTAL FLOW OUT = 36.65
MEaN MONTHLY FLOWS AND DAILY FLOWS
TPIPIJTAQY MONTH Y A ”1 MEAN FL0’4 )A FLOW flAY FLOW DAY FLOW
?7?SAI 10 7 0.1 I 16 0.80
I I 7? 0.60 1? ‘1.51
1’ 1? 0.14
1 71 0.09 0.10
7 73 0.11
1 73 1.I 0.20
4 71 2.4’ 18 2.20
5 71 4.1’) ? 2.70 2.00
6 71 2.15 7 1.20
7 73 0.98
4 71 1.19 19 2.60 25 0.94
0 7 ! o.ci 23 0.30
?726r !l tO 7? 1.10 15 1.20
7’ 0.”9 12 0.80
1? 7?
1 73 0.!? 9 0.10
7 73 0.18
1 73 1.41 0.30
1. 71 1.!? l.’ 3.00
S 71 8. 6 2 3.80 2.80
71 7•Q8 7 1.70
7 73
U 73 1.74 1’# 1.00 25 1.40
9 7 0.71 ‘3 0.50
2725?? 10 7’ 0.1? I’, 0.30
II 7 ” 0.16 1? 0.23
I’ 7?
1 73 Q.0 ’T 9 0.03
7
1 73 0.’4 4 0.10
4 73 ‘i . 7 I
6 71 1.57 7 1.00 19 0.80
4 71 7 0.53
7 73
‘1 73 0.46 10 1.00 0.40
9 73 0.71 71 0.13
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APPENDIX B
PHYSICAL and CHEMICAL DATA
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sT c:r ET9I vaL ) TF 1./IC/ tj
1) T E
7,)
1)21 ‘
C- i_ /IT,
272501
47 ?S ‘.0.0 09? 37 IH.0
EL 0W LAKE
27 MINNEcOTA
1E ALES
2111202
0000 FEET DEPTH
DArE
:- Q
TO
VIMF 71’-l
nr
‘ AY F FT
72/07/02 14 00 0000
72/09/09 14 00 (lOOfl
14 00 t;0 1 4
14 00 fl00 3
7?/lu/l9 14 40 O0)()
14 ‘0 0004
14 ‘ .0 (‘003
L JI’
0UC’
u )7l
00400
Ou 4l O
00630
00610
00665
00666
.At
[ h)
T- a.JSP
C’i ’1CTvY
‘H
I ALK
N0?’ NO3
Nl-13—N
Pt -lOS—TOT
PHOS—DIS
7 ’
‘ EC(Ht
1FLt
CACO3
N—TOTAL
TOTAL
( j 3
IJC- ES
• ICP P1’-iO
SU
MG/L
MU/L
MG/L
MG/L P
MG/L P
11.
57
7?
? ‘
‘7P
.40
9.
7
96
O.O 0
u.110
0.070
0.370
0.900
1.440
0.720
1.270
t ’ .’•
7.7
27’
-4.95
95
0.120
0.350
1.420
1.290
1 .
.l
272
300
M. 9(j
7.50
96
87
0.100
0.280
0.280
1.770
1.400
1.320
1.260
1.260
7. .
300
7.50
87
0.310
1.740
1.340
1.280
5.1
1.3
300
7.30
88
0.320
1.750
1.380
1.260
r)j )T
AI F T
72/0 7/0’
7 /Q /0
7?’ I (‘/ I
l
14 ‘ 0
I L. .C
() fl
3.6)
J V L’J < Q.jr 1 ‘; j
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APPENDIX C
TRIBUTARY DATA
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STORET RET’ TEVAL I)AT€ 74/10/JO
?72541 LS272SAI
47 27 00.0 092 34 00.0
U NA jE [ ) TRIt3 FPOM ELEVETH AREA
7O57 7.5 EVELET9
T/fLHOw LAKF
CO HwY 317 XING BELO EVELETH SIP
IIEPALFS 2111204
0000 FEET DEPTH
00625 00610 00671 00665
DATF TIMF D ’T-1 ‘ O? .NO3 TOT KJEL N -l3— ’J PHOS—DIS PHOS—IOT
FROM OF N-TOTAL TOTAL OPTHO
TO DAY FEET MG/L ir,it P.IG/L MG/L P MG/L P
7?/I1/1? 11 20 u.630 1?.(’00 ‘.400 2.600 3.850
71/04/1 1 4 00 U.43i) 5.150 3.000 0.630 0.990
73/05/02 jQ 30 0.460 .400 - 0.610 0.970
73/05/19 17 55 ‘h SS O 6.Le00 4.200 1.000 1.B80
73f06/07 1 10 0.150 - .4OC 3.600
71/0 /I 14 15 .1J0 3.200 0.040 1.700 1. 80
73/0R/25 17 ‘ 5 .030 1?.IOD lO.Q50 2.900 3.670
73/09/23 ii 15 0.1 k 11.500 9.700 3.000 3.400
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)T FT — T- T “Al )(.r 7 ./ I / j)
?7 tA2 LS 725A2
-41 7 00.0 09? 3’, 00.0
UNN4MEF) TRII F OM EVILETH A FA
7.- FvELET-
I/ LLhOW LAKt
( U r Y 19 XIN( ‘ OF Lr 0N J’JNCTIO”J
1IF- L S ?111204
(.000 Ff ET DEPT,-i
-( -,) 00 ’ ,7l
‘)A TE I 1 ‘ - i — i I ‘) J L ‘ 4OS—DIS P .-iO —TOT
TIiIAL
T’) ‘ ‘L
72/) /j ‘.‘ i.. ) i J. Il) .100 1.37 ,
7?/ I I/I -‘ I” I . ‘. • - 7:j I • 245 •
71/ ‘1 • / I -‘ I • - -i • ‘.1 • - u • ‘ 0 U • 1
7 /’j /)? I ( ) ).‘- — _ 0. Su
71/. c/I- Ii .71’ 1 •( - - 0 .1- 40
73/0’ -/07 14 -‘• ‘•‘• 1.700
71/ ’ /) i i• 1.?(’O 1. -”-(’
71/ ’ J,’- I I 1 ” - ..- •‘-‘ 1” 1 • 1 ’- 1 .00 ?. 100
71/ ’ /7 11 1— 1.1’ . 1 — 1. flo
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ST0° T QE T I VAL I)AT 7’4/1 ,/30
27 25tj1 LS2725q1
47 5 00.0 09? 36 30.0
tL’- 0vJ Cf F.Et’
d7 7.5 EvELE:T -’
0/ELBOw LAP
C ) HwY 45? XING SW OF IRON JUNCTION
) IEPALES 2111204
4 0000 FEET DE?TH
0067) 00665
DATE I 1 r 1 )10TH 4O rI03 101 KJ L r13—N P i0S—DIS PHOS—TOT
OM 1JTAL N t ljTAL ORTHO
TO O Y F T 4h/L ‘Ah/L ‘ C /L r4G/L P MG/L
7?/Ifl/1S 17 10 J.7 O ).c ’ ‘ .‘ ?0 0.165
72/11/1? 11 10 i,.$s-’O ) . 0fl 0.200
71/ ”/I j .4 45 7 .b0J t .lC 0 0 .’70
71/ ,S/r)7 N 15 ‘i.) 3 0.?4 0 Ij.4 5 0
7l/0S/l l1 1 ‘. 10 C.117 0.410 0.450
71/0f /0F )4 7 ..7 i O. .20 0. 4fl 0.900
71/C /1° 14 ‘ )‘ • 47Q 0.’—6fl 0.046 0. 10
71/r,.R/2c, 17 15 ‘i. lN 0.OOU 0.R70 0.900
73/0 4/?1 11 ‘S c.65 ) 4.10(i 0. 6O 0.147
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