U.S. ENVIRONMENTAL PROTECTION AGENCY
NATIONAL EUTROPHICATION SURVEY
WORKING PAPER SERIES
REPORT
ON
LAKE DARLING
DOUGLAS COUNTY
MINNESOTA
EPA REGION V
WORKING PAPER No, 96
PACIFIC NORTHWEST ENVIRONMENTAL RESEARCH LABORATORY
An Associate Laboratory of the
NATIONAL ENVIRONMENTAL RESEARCH CENTER • CORVALLIS, OREGON
and
NATIONAL ENVIRONMENTAL RESEARCH CENTER - LAS VEGAS, NEVADA
•fa opo 697.O32
-------
REPORT
ON
LAKE DARLING
DOUGLAS COW1Y
MINNESOTA
EPA REGION V
WORKING PAPER No, 96
WITH THE COOPERATION OF THE
MINNESOTA POLLUTION CONTROL AGENCY
AND THE
MINNESOTA NATIONAL GUARD
JANUARY, 1075
-------
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
IV. Nutrient Loadings 8
V. Literature Reviewed 12
VI. Appendices 13
-------
11
FOREWORD
The National Eutrophication Survey was initiated in 1972 in
response to an Administration cornniitment 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 [ g303(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.
-------
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 appreciatiQn 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.
-------
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
Cleat-water 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 Horrune Dieu Douglas
Lily Blue Earth
Little Grant
Lost St. Louis
-------
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
Wailmark Chisago
White Bear Washington
Winona Douglas
Wolf Beltrami , Hubbard
Woodcock Kandiyohi
Zumbro Olmstead, Wabasha
-------
vi
LAKE DARLIN
Tributary Saripling Site
iap Location
Lake Sampling Site
450 541
-------
LAKE DARLING
STORET NO. 27B4
I. CONCLUSIONS
A. Trophic Condition:
Survey data indicate that Lake Darling is meso-eutrophic.
Of the 60 Minnesota lakes sampled in the fall when essentially
all were well-mixed, six had less mean total phosphorus, three
had less mean dissolved phosphorus, but 27 had less mean inor-
ganic nitrogen. Of all 80 Minnesota lakes sampled, only nine
had less mean Secchi disc transparency, but 27 had less mean
chlorophyll a.
Depression of dissolved oxygen with depth occurred in July,
and oxygen was depleted below 25 feet in September.
Reportedly (Schilling, 1974), niacrophytes in Lake Darling
have been chemically treated for control.
B. Rate-Limiting Nutrient:
There was a differential loss of nutrients in the assay
sample from the time of collection to the beginning of the
assay, and the results are not indicative of conditions in
the lake at the time of sampling.
The lake data indicate nitrogen limitation in July and
September but phosphorus limitation in October.
-------
2
C. Nutrient Controllability:
There are no known point sources impacting Lake Darling,
and the entire phosphorus load was from non-point sources.
During the sampling year, the lake received a total phos-
phorus load at a rate less than the rate proposed by Vollen-
weider (in press) as “permissible”; i.e., an oligotrophic
rate (see page 11).
-------
3
II. LAKE AND DRAINAGE BASIN CHARACTERISTICS
A. Lake Morphometryt:
1. Surface area: 954 acres.
2. Mean depth: 20.3 feet.
3. Maximum depth: 62 feet.
4. Volume: 19,366 acre-feet.
5. Mean hydraulic retention time: 318 days.
B. Tributary and Outlet:
(See Appendix A for flow data)
1. Tributaries -
2. Outlet -
Lake Carlos inlet
C. Precipitation***:
1. Year of sampling: 22.9 inches.
2. Mean annual: 22.6 inches.
t DNR lake survey map.
* Drainage areas are accurate within ±5%; mean daily flows are accurate
within ±10%; and ungaged flows are accurate within ±10 to 25% for
drainage areas greater than 10 mi 2 .
** Includes area of lake; outflow adjusted to equal Lake Carlos inflow.
See Working Paper No. 1, “Survey Methods”.
‘I
LThRAW( / EPA
N it onal —-i -esr ti Ceut
200 S W .
Corvallis, O eyc fl 9J . U
Name
Lake Cowdry outlet
Lake Alvin outlet
Minor tributaries &
immediate drainage -
Totals
Drainage area*
172.0 mi 2
0.5 mi 2
1.0 mi 2
173.5 mi 2
Mean flow*
30.2 cfs
0.1 cfs
0.4 cfs
30.7 cfs
175.0 mi 2 ** 30.7 cfs**
-------
4
III. LAKE WATER QUALITY SUMMARY
Lake Darling 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 (15 feet to surface)
sample was taken for phytoplankton identification and enumeration;
and a similar sample was collected for chlorophyll a analysis. Dur-
ing the last visit, a single five-gallon depth-integrated sample was
composited for algal assays. The maximum depth sampled was 44 feet.
The results obtained are presented in full in Appendix B, and the
data for the fall sampling period, when the lake essentially was 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.
-------
5
A. Physical and chemical characteristics:
FALL VALUES
(10/25/72)
Parameter Minimum Mean Median Maximum
Temperature (Cent.) 6.4 6.4 6.4 6.4
Dissolved oxygen (mg/l) 10.0 10.6 10.7 11.4
Conductivity (pmhos) 400 409 410 420
pH (units) 8.3 8.4 8.4 8.4
Alkalinity (mg/i) 201 211 216 218
Total P (mg/i) 0.015 0.020 0.017 0.034
Dissolved P (mg/i) 0.008 0.009 0.009 0.013
NO + NO (mg/i) 0.120 0.122 0.120 0.130
Am onia mg/1) 0.070 0.073 0.070 0.090
ALL VALUES
Secchi disc (inches)
84 101
108 110
-------
6
B. Biological characteristics:
1. Phytoplankton -
Sampling Dominant Number
Date Genera per ml
07/06/72 1. Anabaena 1,175
2. Dinobryon 714
3. Microcystis 606
4. Flagellates 262
5. Coelosphaerium 136
Other genera 705
Total 3,598
09/01/72 1 . Microcystis 2,025
2. Lyngbya 1,700
3. Dinobryon 579
4. Anabaena 524
5. Aphanocapsa 452
Other genera 615
Total 5,895
10/25/72 1 . Fragilaria 942
2. Dinobryon 885
3. Anabaena 678
4. Flagellates 377
5. Asterionella 264
Other genera 1,110
Total 4,256
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 )
07/06/ 72 01 18.2
09/01/72 01 8.6
10/25/72 01 8.7
-------
7
C. Limiting Nutrient Study:
There was a differential loss of nutrients in the assay
sample between the time of collection and the beginning of
the assay such that the N/P ratio was shifted from 21/1 in
the lake to li/i in the sample assay. Consequently, the assay
results are not indicative of lake conditions at the time of
sampi ing.
The lake data indicate nitrogen limitation in July (N/P =
8/1) and September (N/P — il/i) but phosphorus limitation in
October (N/P = 21/1).
-------
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
tributary sites indicated on the map (page vi), except for the high
runoff months of April and May when two samples were collected and the
colder months when low flows prevented sampling at the Lake Alvin out-
let. 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
tributary sites nearest the lake.
In this report, nutrient loads for sampled tributaries were calcu-
lated using mean annual concentrations and the mean annual flows.
Nutrient loadings for unsampled “minor tributaries and immediate drain-
age” (“ZZ” of U.S.G.S.) were estimated using the means of the nutrient
loads, in lbs/mi 2 /year, in streams tributary to nearby Big Stone Lake
at stations 2709D-1 , E-1 , F—l , and G—1 and multiplying the means by
the ZZ area in m1 2 .
No known point sources impact Lake Darling.
-------
9
A. Waste Sources:
1. Known municipal - None
2. Known industrial - None
B. Annual Total Phosphorus Loading — Average Year:
1. Inputs -
lbs P1 % of
Source yr total
a. Tributaries (non-point load) -
Lake Cowdry outlet 1,430 88.9
Lake Alvin outlet 10 0.6
b. Minor tributaries & immediate
drainage (non-point load) - 20 1 .2
c. Known municipal - None -
d. Septic tanks - Unknown -
e. Known industrial — None —
f. Direct precipitation* - 150 9.3
Total 1,610 100.0
2. Outputs -
Lake outlet - Lake Carlos inlet 1,160
3. Net annual P accumulation - 450 pounds
* See Working Paper No. 1.
-------
10
C. Annual Total Nitrogen Loading - Average Year:
1. Inputs —
lbsN/ %of
Source yr total
a. Tributaries (non-point load)
Lake Cowdry outlet 68,010 87.4
Lake Alvin outlet 240 0.3
b. Minor tributaries & immediate
drainage (non-point load) — 370 0.5
c. Known municipal - None
d. Septic tanks — Unknown
e. Known industrial - None
f. Direct precipitation* - 9,190 11.8
Total 77,810 100.0
2. Outputs —
Lake outlet - Lake Carlos inlet 72,600
3. Net annual N accumulation — 5,210 pounds
* See Working Paper No. 1.
-------
11
0. Mean Annual Non-point Nutrient Export by Subdrainage Area:
Tributary lbs P/mi 2 /yr lbs N/m1 2 /yr
Lake Cowdry outlet 8 395
Lake Alvin outlet 20 480
E. 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 water would become eutrophic or remain eutrophic;
his “permissible” rate is that which would result in the
receiving water remaining oligotrophic or becoming oligotrophic
if morphometry permitted. A mesotrophic rate would be consid-
ered one between “danqerous” and “permissible”.
Note that Vollenweider’s model may not be applicable to
water bodies with very short hydraulic retention times.
Total Phosphorus Total Nitrogen
Units Total Accumulated Total Accumulated
1bs/acr /yr 1.7 0.5 81.6 5.5
grarns/m /yr 0.19 0.05 9.1 0.6
Volle weider loading rates for phosphorus
(g/m’/yr) based on mean depth and mean
hydraulic retention time of Lake Darling:
“Dangerous” (eutrophic rate) 0.52
“Permissible” (oligotrophic rate) 0.26
-------
12
V. LITERATURE REVIEWED
Schilling, Joel, 1974. Personal communication (summary of infor-
mation on Minnesota lakes). MPCA, Minneapolis.
Vollenweider, Richard A. (in press). Input—output models. Schweiz.
Z. Hydrol.
-------
T’ fl-IIIT Y FLO 1N OPMATIO’j OM 1r 1NESOTA
10/30/74
LA
-------
13
VIE. APPENDICES
APPENDIX A
TRIBUTARY FLOW DATA
-------
nfl ‘1UTA - Y FLO INFOr ”iAT ION FO -4 I ‘ - SO1 A
10/ i’ll 14
COW ‘7 4
‘)A’ L Ic ( L/O F
TOTAL D - E jAr. A JEA OF L.W1
10T *** rkT C 1= -
I 75.00
TOFAL r).JAINA(’,F AP OF LA =
SO’ OF 5tJ -i—PQA1NA(,E A FAS
Ao’3T-IL I’ Fl rlwS A\fl ) UAILY F3 OWS
T P- IT A. )Y MON I
PAY
FLO I )A Y
FLOW I)AY
FLOW
StJ- —DPt 1NAl
,O NAL I/F)
FLOwS
rprouT v
A V
JAN
FF
‘AA.
“AY
JUN
JUL
AUG
S
ncr
NOV
DEC
MEAN
?7R .Al
0 . 6
0.)
n.r
0.04
0.24
0.1
o.,’4
0.12
0.07
0.06
0.10
0.05
0.0?
0.10
?7 —$ -fl
17?. ’ ) ’1
3.’.)
7.”)
?‘. v
53.5’)
c2•3o
5 ’ . )0
33.3).,
23. ,0
12.60
30.10
24.90
i.61
30.15
?7 -4’.CI
175.00
3.—,’,
7 .L3
3.l0
,J4•3. ’ )
51.10
5Y . — )
31.i 0
24.10
1 ’.90
10.70
25.30
.70
30.44
?7 47/
?.S0
0.03
0.05
0.71
0. -a’ .
(,.73
0.3’
0.45
0.23
( ‘.21
0.31
0.21
0.10
0.36
,LJMM4 Y
175.00
tOFAL
FLUIV
114
= 367.01
175.16
IOTAL
FLO,i
001
= 165.00
?7 .A1
10
7?
0. 7
14
0.30
1!
7’
‘,.lS
IS
0.10
12
72
15
Q•fl
I
11
O.
I ’
0.0
)
71
r ,.
2
,•Ø
3
73
‘3.”
II
0.70
1’
)•2
5
0.40
7’
(‘•1)
3
‘S
73
0. ’4
)‘
0.30
i
7 3
‘ . ic
11
u.15
p
7
‘j.1 3
.73
)• 11
9
11
0.)-’
1 ’
0.07
?7 -3 -a- I
I ’)
II
12
I
7
I
4
5
6
7
‘
9
7’
7’
1 ’
7 1
73
73
73
71
73
71
73
73
e 1.1fl
75.’
37.’0
If -. ’ - O
J ’ .7 ’
Iu1.”O
11 ’7.60
-• “ )
‘SC .IO
40.10
45• ’Q
IQ.°O
1’.
N
I-
4
11
S
4
‘
11
71
14
.0J
Tj. 0C ’
Th.Q’)
3’ 3.’J’)
“i. O(’
1?M.0.)
100.00
6Q.0’)
1 ,?0
17
‘3?. 00
-------
APPENDIX B
PHYSICAL and CHEMICAL DATA
-------
STORET RETRIEVAL DATE 74/10/30
278401
45 44 48.0 095 24 10.0
DARLING LAKE
27 MINNESOTA
1 IEPALES 2111202
3 0043 FEET DEPTI-
00010 00300 00077 00094 00400 00410 00630 00610 00665 00666
DATE TIME DEPTH WATER DO TRANSP CNOUCTVY PH T ALK NO2 NO3 NH3—N PHOS—TOT PHOS—DIS
FROM OF TEMP SECCHI FIELD CACO3 N-TOTAL TOTAL
TO DAY FEET CENT MG/L INCHES MICPOHHO SU MG/L MG/L MG/L MG/L P MG/L P
72/07/06 ii 10 0000 84 340 8.50 198 0.040 0.040 0.017 0.012
11 10 0004 20.5 9.6 350 8.50 210 0.040 0.060 0.019 0.011
11 10 0015 20.0 6.8 350 8.50 206 0.030 0.040 0.019 0.008
11 10 0020 19.0
11 10 0022 17.7 4.2 350 8.10 206 0.030 0.040 0.019 0.008
11 10 0025 11.5
11 10 0030 9.8
II 10 0042 9.8 1.4 475 7.50 202 0.080 0.240 0.017 0.008
7?/09 /O1 16 00 0000 19.8 110 400 8.05 197 0.060 0.100 0.017 0.007
16 00 0004 19.9 8.3 380 8.05 194 0.080 0.120 0.015 0.008
16 00 0010 19.9 8.2 380 8.10 194 0.060 0.090 0.015 0.011
16 00 0015 19.9 7.6 380 8.10 191 0.090 0.120 0.016 0.012
16 00 0020 19.9 7.0 380 8.15 190 0.080 0.110 0.016 0.009
16 00 0025 19.6 7.0 380 8.12 192 0.140 0.180 0.013 0.009
16 00 0030 15.5 0.0 400 7.40 197 0.140 0.370 0.016 0.007
16 00 0035 13.1 0.0 407 7.30 203 0.130 0.620 0.038 0.014
7?/I0/25 16 30 0000 108 420 8.40 202 0.120 0.070 0.017 0.009
16 30 0004 6.4 11.4 410 8.40 216 0.120 0.070 0.015 0.008
16 30 0015 6.4 10.8 400 8.40 216 0.120 0.070 0.015 0.008
16 30 0025 6.4 10.7 410 8.40 218 0.120 0.070 0.017 0.009
16 30 0035 6.4 10.3 405 8.30 214 0.120 0.070 0.019 0.009
16 30 0044 6.4 10.0 410 8.30 20) 0.130 0.090 0.034 0.013
3?21 7
DATE TIME DEPT $ CtILRPHYL
FROM OF A
TO DAY FEET UG/L
7?/07/06 11 10 0000 18.2J
7?/09/0I 16 00 0000 8.6J
7?/IO/25 16 30 0000 8.7J
J VMLUE P NOWN TO tIE IN ERROR
-------
APPENDIX C
TRIBUTARY DATA
-------
STO ET RETRIEVAl DATE 74/1’ ’30
27’44A1 LS27 4A1
45 55 30.0 095 24 00.0
LK 4L IIN/L DAPLING CONNECTION
27 7.5 ALEXANDRIA W
T/LAKE DAPLING
uI T HD ENDING AT LK CONNECTION
1IEPALES 2111204
4 0000 FEET DEPTH
J 3O 00h25 00€10 O0’ 71 006h5
DATE TIME D PT9 NO?&H03 TOT I
-------
ST0PE T FrPT iAL I)ATE 7L./10/ W
7’i4I-31 L52734R1
‘.5 54 30.0 0Q5 2 . 30.0
LK COw’ Y/LK DAPLI G CONN
27 7.5 ALEXANU flA W
1/LAKE DARLING
Co H 1Y 2? BROG N OF ALEXANORIA
11EPALES 2111204
0000 FEET DEPTH
( 0 25 00 10 00671 00665
JATE Tp.4F DE°T- N02g.NO3 TOT KJEL N-i1— ” P’-IOS—PTS P’-405—TOT
FPO’I 4—TI)TAL TOTAL UPTr$O
TO PAY FFFT M ’/L ‘1G/L M( /L MG/L P MC,/L P
7?/1)/14 10 0 C.03 1.’ 0O 0.(s69 0.005K 0.011
7?/11/1 15 1.s ¶ .05’ 0.Q’O 0 .fl4 0.009 0.025
7?/1?/15 17 60 1.0 4 0.44’ ( . )46 0.005K 0.016
71/0 1/12 1” 00 (I.L I o.075 0.011 ().02fl
71/0?/?1 H) )0 1. 1 ’- C.410 3.045 0.00# 0.030
71/03/11 0.066 0.01F
73/04/05 11 45 .0k c4 ?.3 0.005K 0.020
71/05/O 14 70 ‘.01 0. J .014 0.009 0.025
71/05/17 16 30 ( .0I - 0.740 1.01? 0.005K 0.010
71/0 ’/0 10 5 1.Q5 ., 0.701 .04? 0.005K 0.C20
71/07/LI 1.400 ..11 •).0’ ’i 3.u3 - 0.010 0.0?u
71/06/’ l ‘,0I - 1.”50 .337 0.013 0.025
71/0Q/I 1 IS .OlJrs I. .)C t j.ljJ4 fl. 007 0.025
K V .LtJh cNOWN TO r4E LESS
THAN 1” DJCATFD
------- |