U.S. ENVIRONMENTAL PROTECTION AGENCY
NATIONAL EUTROPHICATION SURVEY
WORKING PAPER SERIES
The Relationships of Phosphorus
and Nitrogen to the Trophic State
of Northeast and North-Central
Lakes and Reservoirs
Working Paper No. 23
Preliminary Analysis of
National Eutrophication Survey Data
Collected During
the 1972-73 Sampling Period
PACIFIC NORTHWEST ENVIRONMENTAL RESEARCH LABORATORY
An Associate Laboratory of the
NATIONAL ENVIRONMENTAL RESEARCH CENTER - CORVALLIS, OREGON
and
NATIONAL ENVIRONMENTAL RESEARCH CENTER - LAS VEGAS, NEVADA
-------
The Relationships of Phosphorus
and Nitrogen to the Trophic State
of Northeast and North-Central
Lakes and Reservoirs
Working Paper No. 23
Preliminary Analysis of
National Eutrophication Survey Data
Collected During
the 1972-73 Sampling Period
National Eutrophication Survey
Pacific Northwest Environmental Research Laboratory, Corvallis, Oregon
December, 1974
-------
DATA FOR FIGURES 6 and 7
(Page 4)
Mean Depth/Ret’n Time P Lo ding N Lo ding
Storet # Lake Name ( meters/years) ( g/m /yr) ( g/m /yr )
6 IO Chautauqua 4.89 0.34 5.56
361 -1 Cross 288.4 33.7 504.6
3633 Saratoga 16.0 1.26 18.9
-------
I NTRODUCTI ON
During the past 30 years, considerable effort has been spent by
numerous investigators studying the various factors which are causing
water bodies to become eutrophic. The preponderance of evidence indi-
cates that controlling phosphorus is the single most Important step
that can be taken at the present time to alleviate nuisance conditions
and other interferences with water uses caused by eutrophication of
water bodies (Bartsch, 1972). One of the major questions to be answered
in developing a eutrophication control program is “What phosphorus level
is necessary to attain the desired trophic condition”.
The question of nutrient levels both from the standpoint of “con-
centration” and “loading” is being addressed by the National Eutro-
phication Survey (NES). A review of the two approaches is presented
in this report as well as the preliminary findings of the National
Eutrophication Survey for lakes and reservoirs sampled in ten north-
eastern and north—central states (Connecticut, Maine, Massachusetts,
Michigan, Minnesota, New Hampshire, New York, Rhode Island, Vermont
and Wisconsin).
Within the past few years, there has been a controversy concern-
ing the establishment of lake water quality criteria for phosphorus
and whether or not they should be based on phosphorus concentrations
within a lake or on phosphorus loading rates to a lake. The question of
a single, nation—wide phosphorus criterion versus individually tailored
-------
2
criteria for specific areas, or some compromise between the two, has also
been discussed.
The concept of the concentration criteria is the older of the two,
dating back primarily to Sawyer (1947) who suggested that concentrations
at spring turnover of 0.010 mg/l of inorganic phosphorus and 0.300 mg/i
of Inorganic nitrogen were critical levels in the development of algal
blooms. The concept of loading rate criteria stems largely from the work
of Vollenweider (1968) who developed a relationship between annual nutrient
loading rates and mean depth from which “permissible” and “dangerous”
loading rates could be estimated for a lake with a given mean depth.
Vollenweider (1974) later refined his relationship to take into con-
sideration the mean hydraulic retention time of lakes as well as the mean
depth characteristic.
In 1968, the National Technical Advisory Committee Report recommended
the following for plant nutrients and nuisance organisms:
Recomendation: The Subcommittee wishes to stress that the
concentrations set forth are suggested solely as guidelines and
the maintenance of these may or may not prevent undesirable
blooms. All the factors causing nuisance plant growths and the
level of each which should not be exceeded are not known.
(1) In order to limit nuisance growths, the addition of
all organic wastes such as sewage, food processing, cannery,
and industrial wastes containing nutrients, vitamins, trace
elements, and growth stimulants should be carefully controlled.
Furthermore, it should be pointed out that the addition of
sulfates or manganese oxide to a lake should be limited if iron
is present in the hypolimnion as they may increase the quantity
of available phosphorus.
-------
3
(2) Nothing should be added that causes an increased zone
of anaerobic decomposition of a lake or reservoir.
(3) The naturally occurring ratios and amounts of nitrogen
(particularly nitrate and ammonia) to total phosphorus should
not be radically changed by the addition of materials. As a
guideline, the concentrations of total phosphorus should not be
increased to levels exceeding 100 pg/i in flowing streams or 50
pg/i where streams enter lakes or reservoirs.
(4) Because of our present limited knowledge of conditions
promoting nuisance growth, we must have a biological monitoring
program to determine the effectiveness of the control measure
put into operation. A monitoring program can detect in their
early stages the development of undesirable changes in amounts
and kinds of rooted aquatics and the condition of algal growths.
With periodic monitoring such undesirable trends can be detected
and corrected by more stringent regulation of added organics.
The recommendation of the 1972 Water Quality Criteria Report of the
National Academy of Science was as follows:
Recommendation: The principal recommendations for aesthetic
and recreational uses of lakes, ponds, rivers, estuaries, and
near-shore coastal waters are that these uses continue to be
pleasing and undiminished by effects of cultural activities that
increase plant nutrients. The trophic level and natural rate
of eutrophication that exists, or would exist, in these waters
in the absence of man’s activities is considered the reference
level and the comonly desirable level to be maintained. Such
water should not have a demonstrable accelerated production of
algae growth in excess of rates normally expected for the same
type of water body in nature without man-made influences.
The concentrations of phosphorus and nitrogen mentioned in
the text as leading to accelerated eutrophication were developed
from the studies for certain aquatic systems: maintenance of
lower concentrations may or may not prevent eutrophic conditions.
All the factors causing nuisance plant growths and the level of
each which should not be exceeded are not known. However,
nuisance growths will be limited if the addition of all wastes
such as sewage, food processing, cannery, and industrial wastes
containing nutrients, vitamins, trace elements, and growth
stimulants are carefully controlled and nothing is added that
-------
4
causes a slow overall decrease of average dissolved oxygen
concentration in the hypolimnion and an increase in the
extent and duration of anaerobic conditions.
In the Proposed Criteria for Water Quality, October 1973, the
Environmental Protection Agency presented the following:
Nutrient (Phosphorus )
No limit of acceptability is prescribed for phosphorus
(P) in recreational waters.
Rationale (Phosphorus):
Acceptable limits for phosphorus in receiving waters
where it is a limiting constituent for nuisance aquatic
plant growths are believed to be:
Maximum Phosphorus
Water Body ( P) Concentration
Within lakes and reservoirs 25 pg/i
At a point where a river
enters a lake or reservoir 50 pg/i
Flowing streams 100 pg/i
Exceptions to the above, including a non-degradation clause, are further
explained in the text of the proposed criteria.
CONCENTRATION APPROACH
Dillon and Rigier (1974), expanding on the work of Sakamoto (1966)
related total phosphorus concentration at spring overturn to summer
chlorophyll a concentrations (Figure 1) for lakes having a nitrogen to
phosphorus ratio of greater than 12, i.e., phosphorus limited. A regression
-------
5
100 1000
TOTAL PHOSPHORUS mgn 3
Figure 1 The Relationship of Summer Average Chlorophyll to Spring
Total Phosphorus (Dillon and Rigler, 1974)
1000
/
.
.
S
A
C ,,
0)
E
0I
-a
>-
0.
0
0
I
U
‘U
I -I )
A.
A
A A
A
100
10
w
.1
S
A
•.
.7/
I.
• = values from Sakamoto (1966)
A = literature values compiled
by Dillon and Rigler (1974)
10
-------
6
analysis of the data they presented resulted in the following relationship:
log 10 [ Chl J = 1.449 log 10 total - 1.136
where both chlorophyll a and total phosphorus concentrations are expressed
in mg/nieter 3 (equivalent to micrograms/liter). The correlation coefficient
for Dillon and Rigler’s data was 0.95 which is extremely good.
A similar relationship was developed by the National Eutrophication
Survey (NES), using the data which were available from selected 1972 study
lakes (Figure 2). For the NES lakes, the median total phosphorus value
for all samplings was plotted against the mean chlorophyll a concentration
for all samplings for lakes with an inorganic nitrogen to dissolved phos-
phorus ratio of 14 or greater. The 14:1 rather than 12:1 ratio was used
because it is more conservative and its use is less likely to include
nitrogen limited lakes. The scatter of the NES data (r = 0.78) was
substantially greater than Dillon and Rigler reported (r = 0.95); how-
ever, for given chlorophyll a concentrations, corresponding total phos-
phorus concentrations from the NES relationship were very similar to
Dillon and Rigler values at phosphorus concentrations below 0.05 mg/i.
The equation describing the regression line in Figure 2 is as follows:
Log 10 ‘tota1 = 0.846 log 10 [ Chl !:1 - 2.354
where total phosphorus is expressed in mg/i and chlorophyll am micro-
grams/i iter.
-------
r =0.78
10.00
C l)
1.00
0
I
0
Cl)
0
I
- 0.10
_j —4
I-
0
z
0.01
L i i
0.001
1.0 1000.0
MEAN CHLOROPHYLL (pg/I)
FIGURE 2 THE RELATIONSHIP BETWEEN MEDIAN TOTAL PHOSPHORUS
AND MEAN CHLOROPHYLL IN PHOSPHORUS LIMITED LAKES
log 10 totaI =0.846 log 10 ChI —2.354
U
U
.
U UU
U
U
U
.
U.
S.
U
U
.
U..
U •
.
•
S
• =EUTROPHIC
A =MESOTROPHIC
• =OLIGOTROPHIC
10.0 100.0
-------
8
For comparative purposes total phosphorus concentrations determined by
Dillon’s equation are equated with those determined by the NES relation-
ship at several chlorophyll a concentrations as illustrated below.
Comparison of Dillon and Rigler Equation with the NES
Equation for Various Chlorophyll a Concentrations
Total Phosphorus Concentrations
Calculated from Respective
Regression Equations
Dillon & Rigler NES
Chlorophyll a Total P Total P
( pg/l) ( pg/i) ( pg/i )
1 6.1 4.4
5 18.4 17.4
10 29.8 30.9
25 56.2 67.9
50 90.6 120.0
100 145.9 219.0
The symbols on each point in Figure 2 represent one of the classic
trophic conditions, i.e., oligotrophic, mesotrophic, or eutrophic. It
is recognized that these terms are very subjective and difficult to
define in absolute values, nevertheless, they are widely used in the
scientific community and are understood by most scientists to be indi-
cators of lake quality. The term “eutrophic” covers a myriad of water
quality conditions ranging from the very desirable lakes which support
excellent warniwater fisheries (and which may also experience nuisance
algal blooms) to lakes which are in essence comparable to pea soup and
are of no value for any beneficial use except perhaps as sources of
-------
9
irrigation water. Oligotrophic and mesotrophic lakes are generally
considered to be free of nuisance phytoplankton blooms and specifically
of blue-green algae nuisances.
The NES staff assigned trophic conditions to each of the lakes repre-
sented in Figure 2 based on pertinent chemical, biological, and physical
data collected by the Survey, data available from state agencies or other
sources, and frequently including communication with state personnel who
had personal knowledge of the lake in question.
Several observations can be made concerning the relationships in
Figure 2. Those lakes classified as oligotrophic did not exceed a median
total phosphorus concentration of 10 pg/i or a mean chlorophyll a con-
centration of 7 pg/i. Median total phosphorus concentrations in the
mesotrophic lakes did not exceed 18 pg/l and chlorophyll a means did
not exceed 12 pg/i. The majority, but not all, of the eutrophic lakes
had median total phosphorus concentrations greater than 18 pg/i.
These observations relating trophic condition to total phosphorus
and chlorophyll a levels fit reasonably well with chlorophyll a ranges,
corresponding to the various trophic conditions, suggested by others
(Sakamoto, 1966; National Academy of Sciences, 1972; Dobson et al., 1974)
as indicated below:
Chlorophyll a (pg/i)
Trophic Condition Sakamoto Academy Dobson Survey
Oligotrophic 0.3-2.5 0-4 0-4.3 <7
Mesotrophic 1-15 4-10 4.3-8.8 7-12
Eutrophic 5-140 >10 >8.8 >12
-------
10
On the basis of the Survey’s chlorophyll a to total phosphorus
relationship and the chlorophyll a range give by the National Academy
of Sciences, the following phosphorus guidelines would be suggested:
Trophic State Chlorophyll a (pg/i) Total Phosphorus (pg/i )
Oligotrophic <4 <14
Mesotrophic 4-10 15-30
Eutrophic >10 >30
If a phosphorus guideline were established empirically on the basis
of the data presented in Figure 2, the following would be concluded:
Trophic State Chlorophyll a (pg/l) Total Phosphorus (pg/l )
Oligotrophic <7 <10
Mesotrophic 7-12 10—20
Eutrophic >12 >20
It should be noted that the suggested guidelines presented above and,
in fact, in the remainder of this report, apply only to those water bodies
where phytoplankton and not aquatic macrophytes dominate primary production.
Figure 3 represents the relationship between median total phosphorus
and mean Secchi disc depths for those lakes with an inorganic nitrogen:
dissolved phosphorus ratio greater than 14. The correlation coefficient
for this relationship was -0.82 and the line of best fit is described by
the following equation:
log 10 total = -1.307 (log 10 Secchi) + 0.818
-------
ii
where the units of total phosphorus are mg/i and Secchi disc depth units
are inches.
Empirically, these data suggest that mean Secchl disc depth in meso-
trophic lakes will exceed 78 inches (2 meters) and in oligotrophic lakes,
144 inches (3.7 meters), as indicated in the table below. One oligotrophic
lake plotted in Figure 3 had a mean Secchi disc depth of less than 3.7
meters; however, the value did not represent the maximum transparency be-
cause on at least one occasion, the Secchi disc was resting on the lake
bed when the reading was made (Thomas, 1974).
Trophic State Secchi Disc Depth
Oligotrophic >12.1 feet (3.7 meters)
Mesotrophic >6.6 feet (2.0 meters)
Eutrophic <6.6 feet (2.0 meters)
The suggested guidelines for Secchi disc depths corresponding to
the three major trophic conditions are somewhat lower than would be
expected, based on literature values. Lueschow, et al. (1970), who
reported on studies of 12 Wisconsin lakes, stated that lakes with mean
Secchi disc depth greater than 12 feet (3.7 meters) experienced no
deterioration of recreation potential due to plankton growths. This
Secchi disc depth corresponds to the NES assigned oligotrophic condi-
tion and a total phosphorus concentration of 10 jig/l or less.
In the Proposed Criteria for Water Quality, October, 1973, EPA sug-
gested a minimum water transparency of 4 feet (1.2 meters) for bathing
-------
10.0
a,
0.001
1000.0
MEAN SECCHI DISC DEPTHS (INCHES)
FIGURE 3 THE RELATIONSHIP BETWEEN MEDIAN TOTAL PHOSPHORUS
AND MEAN SECCHI DISC DEPTHS IN PHOSPHORUS LIMITED
LAKES
r =—O.82
log 10 totaI =0.818—1.307 10910 SD
U
U
.
U
U
U.
. U
U
U
U
U
p
U
• = EUTROPHIC
= MESOTROPHIC
• = OLIGOTROPHIC
U
U
U
U
U
U
U
•
10.0 100.0
-------
13
areas. Using the NES regression equation, this transparency corresponds
to a total phosphorus concentration of 42 g/l which represents a very
enriched condition and is therefore not suggested as a desirable guide-
line for total phosphorus.
The relationship between the control algal assay yield and the median
fall total phosphorus concentration is depicted by Figure 4. The regression
line for this relationship is:
log 10 (Ptotai) = 0.419 log 10 (AA Yield) - 1.603
where total phosphorus and algal assay yield are expressed in mg/i. All of
the oligotrophic and mesotrophic lakes except one (Lake Champlain) had
control yields of 0.9 mg/i dry weight or less. Based on the regression
line, a yield of 0.9 mg/i corresponds to a median fall phosphorus concen-
tration of 25 jig/liter, which fits well with the phosphorus guidelines
suggested by the previously discussed relationships.
Miller, Maloney, and Greene (1974) assigned four levels of productivity
to algal assay control yields in their study of 49 U.S. lakes, including a
range from 0.1 mg/l to 0.8 mg/i which they described as moderate productiv-
ity and which corresponded to mesotrophic conditions. Their data agree
with the Survey observations.
As determined by the algal assay procedure, about 57% of all the lakes
sampled in 1972 were phosphorus limited, while 37% were limited by nitrogen,
1% were limited by an unidentified element and the data were not conclusive
for the other 5% of the lakes.
-------
r -0.82
lOglOPtotal —0.419 10910 AA—l.603
I I I I 11111
I I I I 11111
I I I I 11111
I I I I I III
0.1 1.0 10.0 100.0
ALGAL ASSAY CONTROL YIELD (Mg/I)
FIGURE 4 THE RELATIONSHIP BETWEEN MEDIAN TOTAL PHOSPHORUS DURING
THE FALL SAMPLING AND ALGAL ASSAY CONTROL YIELDS
10.0
C l )
a:
0
U I ’.
1 4 U
£
U
U.
U
U
•U
e
.
U
•.U
£
.*
U.
U.
U
U
U
a
U
U =EUTROPHIC
£ -MESOTROPHIC
• -OLIGOTROPHIC
-------
15
In summary, suggested guidelines for total phosphorus as determined by
concentration approach ranged from 20-30 yg/1 using the various chlorophyll
^relationships. Depending on whether the Leuchow, et al. recommendation
of a minimum 12 foot Secchi disc reading to maintain nuisance-free condi-
tions or the proposed Water Quality Criteria's recommendation of a minimum
4-foot Secchi disc reading for bathing areas is used, a total phosphorus
guideline of 10 to 40 yg/1 would be suggested. The algal assay relation-
ship on the other hand, suggests a total phosphorus guideline of 25 yg/1.
The above guidelines, based on this preliminary analysis of the data,
generally support the Proposed Water Quality Criteria of 25 yg/1 as a level
which should not be exceeded in lakes or reservoirs to maintain conditions
free of nuisance blooms.
Summary data, from which the points on Figures 2 through 4 were derived,
are presented in Appendix A to this report.
LOADING APPROACH
The first attempt to unify the nutrient loading concept with the
trophic condition of lakes was made by Vollenweider in 1968. He related
•j
total phosphorus loadings (g/m lake surface area/year) to the mean depths
of lakes and then empirically determined the loading rates corresponding to
the three classical trophic conditions; oligotrophic, mesotrophic and
eutrophic. A similar relationship was derived for nitrogen loading,
assuming that algal nitrogen requirements were related to phosphorus
requirements in the ratio of 15:1.
-------
16
In order to account for large differences in flushing rates of lakes,
Vollenweider (1973) later modified his relationship by plotting total
phosphorus load (g/m 2 /yr) against the ratio of mean depth to mean hydraulic
detention time. This modification was based on a theoretical input —output
model which he had also developed.
Using Vollenweider’s newest relationship, preliminary data from the
Survey for selected phosphorus limited lakes were graphed as illustrated
in Figure .
The lines in Figure 5 correspond to Vollenweider’s empirical permissi-
ble and critical loading rates which, in effect, are observed limits be-
tween for oligotrophic—mesotrophic and mesotrophic-eutrophic lakes.
In general, Figure 5 indicates that the Vollenweider loading concept
holds true when tested with Survey data although there were exceptions
and also a scarcity of lakes included in the Survey which had low mean
depth to detention time ratios, were eutrophic, and phosphorus limited.
At least two of the lakes or reservoirs which were eutrophic and had
phosphorus loadings less than the critical loading were dominated by aquatic
ruacrophytes rather than phytoplankton.
The two mesotrophic lakes which exceed the critical loading are
very deep and therefore have a large assimilative capacity. Green Lake
(Wisconsin) has a mean depth of 32 meters and Cayuga Lake (New York) has
a mean depth of 52 meters. Conceivably, neither of these lakes may have
achieved a trophic condition in equilibrium with the phosphorus input.
Both lakes receive heavy nutrient loads from municipal sewage treatment
plants.
-------
I 10 100 1000
MEAN DEPTH (METERS) /MEAN HYDRAULIC RETENTION TIME (YEARS)
FIGURE 5 THE RELATIONSHIP OF TOTAL PHOSPHORUS LOADING AND LAKE MORPHOMETRY
TO TROPHIC CONDITION OF PHOSPHORUS LIMITED LAKES
• =EUTROPHIC
£ LZMESOTROPHIC
• =OLIGOTROPHIC
0
z
.
0
-J
C,)
D
0
(I)
0
I
0
-J
I-
0
I—
100
I0
1.0
0.1
0.01
0.1
-------
18
Figure 6 represents total phosphorus loadings to those lakes and
reservoirs which were nitrogen limited. The nitrogen-limited status
was assigned with reservations because some blue-green algal species
are nitrogen-fixers and could thrive in waters which are nitrogen
limited for other species. There are two interesting points to note
about the data presented in Figure 6. First, all of the nitrogen-limited
lakes were eutrophic indicating that nitrogen limitation generally occurs
only in very enriched systems or after cultural enrichment. The only
known exception to this rule is Lake Tahoe which is oligotrophic but
nitrogen—limited (Lake Tahoe Area Council, 1971). The second point is
that the phosphorus loadings for all but six of the water bodies equal
or exceed Vollenweider’s critical loading level. Many of the lakes
represented in Figure 6 could probably have their trophic condition
improved and be made phosphorus limited by reducing their phosphorus
loading below Vollenweider’s critical loading value.
Figure 7 represents the total nitrogen loading for the same nitrogen-
limited lakes considered in Figure 6. If one assumes that the nitrogen
to phosphorus requirements of algae are 14:1 (which is probably conserva-
tive), then a theoretical critical line for nitrogen loading can be con-
structed on the basis of the critical phosphorus loadings. The critical
loading line in Figure 6 was constructed on that basis and all of the
points representing lakes, except five, exceed the critical loading level
for nitrogen.
-------
1000.0
100.0
10.0
1.0
a-
C l )
0
I
a-
-J
I—
0
I—
0.01
0.1 1.0 10 100 1000
MEAN DEPTH (METERS) /MEAN HYDRAULIC RETENTION TIME (YEARS)
FIGURE 6 THE RELATIONSHIP OF TOTAL PHOSPHORUS LOADING AND LAKE MORPHOMETRY
TO THE TROPHIC CONDITION OF NITROGEN LIMITED LAKES
-------
1000.0
MEAN DEPTH (METERS) /MEAN
10 100
HYDRAULIC RETENTION TIME (YEARS)
FIGURE 7 THE RELATIONSHIP OF TOTAL NITROGEN LOADING AND LAKE MORPHOMETRY
TO TROPHIC CONDITION OF NITROGEN LIMITED LAKES
N)
1000
C D
z
0
-J
z
w
C D
0
I—
z
-J
I—
0
I—
100.0
10.0
1.0
0.1
0.I
0.01
-------
21
It is not suggested that a water quality criteria or guideline for
nitrogen be formulated for wide application. Nitrogen is not as con-
trollable material, like phosphorus and is generally available in large
quantities to aquatic systems from a variety of diffuse sources including
land runoff, precipitation and nitrogen fixation. The formulation and
widespread application of a criterion or guideline for nitrogen would
only serve to confuse and detract from the main issue which should be
phosphorus control in the majority of cases.
A relationship like Figure 7, however, might be useful in special
cases such as Lake Tahoe. One other point of interest in Figure 7 is
the apparent linearity of the relationship between nitrogen loadings
and the mean depth to detention time ratio. The phenomenon does not
have any great significance to the criteria Issue but is explained by
the fact that, generally, as the mean depth to detention time ratio in-
creases so does the drainage area to surface area ratio. Since nitrogen
export per unit of drainage area is relatively constant, total nitrogen
load increases proportionally with drainage area size without appreciable
scattering. These factors in combination tend to produce the linear
relationship observed in Figure 7.
Summary data from which the points on Figures 5 through 7 were
derived are presented in Appendix B to this report.
-------
22
DISCUSSION
Two concepts of developing phosphorus criteria for controlling eutro-
phication in lakes and impoundments have been presented. From a manage-
ment viewpoint, a loading rate criteria would be easier to work with than
lake concentration criteria because the former Is one step closer to the
source of nutrient supply; therefore, once a desirable loading rate to a
given water body is established, it would be relatively easy to determine
the extent of phosphorus reduction from point sources and non-point sources
necessary to achieve the desired loading.
On the other hand, if a concentration criterion alone were applied
to a water body, the back calculation necessary to determine the phosphorus
reduction necessary to meet that concentration level would be much more
difficult because the relationship between concentration in a lake and
loading to a lake is complex. Factors such as volume, detention time,
mixing patterns, biological activity, sedimentation rates and resolubiliza-
tion of phosphorus from the sediments all play a role in determining the
concentration that will result from a given loading rate.
A single loading rate criterion for a lake also has disadvantages
because it is applied with the assumption that the loading is equally
distributed to all parts of the lake. This assumption is often invalid
particularly in larger lakes or reservoirs with several tributary streams
each carrying different nutrient loads. While the average loading rate
to the entire lake may appear acceptable, phosphorus loads in some embay-
ments may be excessively high, resulting in localized nuisance problems,
-------
23
while other areas may receive very light phosphorus loads and have no
problems.
Both the loading and concentration concepts, as presented, were not
without exceptions, some of which could be explained and some with no
apparent explanation; however, exceptions are to be expected when working
with ecological systems
This report has dealt primarily with the question of setting a
phosphorus guideline or criterion (loading, concentration, or a combina-
tion of the two) which, if not exceeded, promises a high probability of
avoiding nuisance phytoplankton blooms. It has not addressed the question
of what phosphorus loadings or concentrations are achievable or desirable
for water bodies in different geographical or geological areas, land use
types, climates, etc.
While one might expect to find a large number of oligotrophic lakes
in Maine or Upper New York, oligotrophic lakes through the nutrient-rich
mid-west would be a rarity even without cultural influences. In some areas,
natural phosphorus inputs may be sufficiently great to produce occasional or
frequent phytoplankton blooms which interfere with one or more lake uses.
It would seem logical that numbers such as those presented in this
report could be offered as guidelines which should be followed to achieve
high quality lakes and reservoirs relatively free of nuisance bloom con-
ditions. For enforcement purposes, however, criteria for phosphorus should
be based on the lowest achievable background given the geology, land use,
-------
24
drainage area size, lake morphometry, and other unique factors in each
specific case. Either the concentration or loading approach could be
used in applying such criteria and variances from the lowest achievable
background should be made for specific cases where higher productivity
levels are desired.
A report on additional Survey data investigating the relationship
between land use and other factors influencing nutrient export is being
prepared and should be useful in the further development of this concept.
It should be noted that the data presented in this report represent
only the majority of the information available from the Survey’s first
year of effort in ten northeast and north-central states. As data from
the southeast, midwest, and western states become available, they will be
treated in a similar manner and, in addition, new relationships will be
tested as patterns develop.
SUMMARY AND CONCLUSIONS
Based on preliminary analysis of the data from the first year of the
National Eutrophication Survey, the following statements can be made:
1. A general relationship was described between median total
phosphorus concentrations and chlorophyll a in phosphorus
limited lakes. Although more scatter was noted in the Survey
data, the relationship fitted very well with data previously
presented by Sakarnoto (1966) and Dillon and Rigler (1974).
2. Using the phosphorus-chlorophyll a relationship, several
approaches can be used to suggest phosphorus guidelines to
avoid nuisance phytoplankton blooms. Phosphorus guidelines
determined in this manner ranged from 20-30 pg/i total phos-
phorus.
-------
25
3. The Survey data indicated that all of the oligotrophic
and rnesotrophic lakes had mean chlorophyll a concentrations
less than 12 pg/i.
4. A general relationship was described between median total
phosphorus concentrations and Secchi disc readings which empiri-
cally suggested that, in general, Secchi disc readings in
eutrophic lakes are less than 2 meters. Based on the minimum
transparency of 4 feet (1.2 meters) for bathing areas recom-
mended by the EPA Proposed Criteria for Water Quality, a phos-
phorus guideline of 42 pg/i total phosphorus could be proposed,
although this concentration corresponds to well eutrophied water
which would probably be objectionable for other reasons.
5. Survey data suggested that oligotrophic lakes have Secchi
disc readings greater than 11.8 feet (3.6 meters) and mesotrophic
lakes greater than 6.6 feet (2.0 meters). These values, however,
seem low when compared to those proposed by others.
6. A general relationship was described between median fall
total phosphorus concentrations and control algal assay yield
which empirically suggested a total phosphorus guideline of
25 pg/l to maintain nuisance—free conditions.
7. The guideline for total phosphorus concentrations, suggested
by the relationships developed in this report, generally support
the concentration of 25 pg/i suggested in the “Proposed Water
Quality Criteria” as a level which should not be exceeded in lakes
or reservoirs to maintain conditions free of nuisance blooms.
8. Vollenweider’s loading approach, on the basis of Survey
data, is a viable mechanism for establishing total phos-
phorus loading guidelines for lakes and reservoirs which
are phosphorus limited or can be made phosphorus limited.
Loading limits are established specifically for each lake
based on its mean depth and mean hydraulic retention time
characteristics.
9. Using the Vollenweider concept, a similar relationship
can be developed for deriving total nitrogen loading guide-
lines for nitrogen-limited lakes.
10. All of the nitrogen limited lakes for which data were
presented in this report were eutrophic, indicating that
nitrogen limitation does not generally occur until a lake
system is highly enriched with nutrients. Exceptions to
this rule are known (e.g., Lake Tahoe).
-------
26
11. Because of the variability in each lake system and differences
in natural phosphorus concentrations in surface waters, it is felt
that the numbers suggested in this report can only be presented
as guidelines to avoid the occurrence of nuisance bloom conditions.
These guidelines combined with a knowledge of background nutrient
levels, land use, lake use and lake morphometry could then be used
to establish enforceable nutrient criteria on a lake by lake basis.
-------
27
REFERENCES
1. Bartsch, A. F., 1972. Role of Phosphorus in Eutrophication. U.S.
EPA Ecological Research Series No. EPA-R3-72-OOl.
2. Dillon, D. J., and F. H. Rigler, 1974. The Phosphorus-Chlorophyll
Relationship in Lakes. Limnol. Oceanogr. 19:767-773.
3. Dobson, H. F. H., M. Gilbertson, and P. G. Sly, 1974. A Summary
and Comparison of Nutrients and Related Water Quality in Lakes
Erie, Ontario, Huron and Superior. J. Fish. Res. Bd. Can. 31:
731 —738.
4. Federal Water Quality Control Administration, 1968. Water Quality
Criteria, Report of the National Technical Advisory Committee to
the Secretary of the Interior, Washington, D.C.
5. Lake Tahoe Area Council, 1971. EutrophIcation of Surface Waters -
Lake Tahoe. U.S. EPA Water Pollution Control Research Series No.
16010 DSW 05/71.
6. Leuschow, L. A., J. M. Helm, D. R. Winter, and G. W. Karl, 1970.
Trophic Nature of Selected Wisconsin Lakes. Wisc. Acad. Sci. Arts.
Letters. 58:237-264.
7. Miller, W. E., 1. E. Maloney, and J. C. Greene, 1974. Algal Produc-
tivity in 49 Lake Waters as Determined by Algal Assays. Water
Research. 8:667-679.
8. National Academy of Science and National Academy of Engineering, 1972.
Water Quality Criteria, A Report of the Committee on Water Quality
Criteria, Washington, D.C.
9. Sakamoto, M., 1966. Primary Production by Phytoplankton Comunity
in some Japanese lakes and its dependence on lake depth, Arch.
Hydrobiol. 62:1-28.
10. Sawyer, C. N., 1947. Fertilization of Lake by Agriculture and Urban
Drainage, N. England Water Works Assoc. 61:109-127.
11. Thomas, R. W., 1974. Personal communication. U.S. Environmental
Protection Agency, Las Vegas, Nevada.
12. U.S. Environmental Protection Agency, 1973. Proposed Criteria for
Water Quality, Washington, D.C.
-------
28
13. Vollenweider, R. A., 1968. The Scientific Basis of Lake and Stream
Eutrophication with particular reference to phosphorus and nitrogen
as eutrophication status. Tech. Report OECD Paris DAS/CSI/68, 27:
1-182.
14. Vollenweider, R. A. (in press). Input-output Models. Schweizerische
Zeitschrift fuer Hydrologie.
-------
APPENDIX A
-------
LAKE MEAN MEAN MEDIAN MEDIAN TROPHIC
CODE LAKE NAME SECCNI CLOR-A TP(YR) TP(FALL) AA YIELD STATE
0910 7OAR LAKE 74.3333 18.2667 0.0430 0.0430 8.1000 E
0911 LILLINOAH LAKE 146.0000 11.1333 0.0540 0.0540 12.2000 C
0912 SHELTON LAKE 75.5000 10.2500 0.0395 0.0370 2.9000 E
2309 MOOSEHEAD LAKE 148.9524 1.4619 0.0050 0.0090 0.8400 0
2310 PANGELEY LAKE 148.2857 2.4333 0.0070 0.0070 0.4000 0
2311 SEBAGO LAKE 199.0667 1.4867 0.0040 0.0080 0.1000 0
2313 LONG LAKE 103.8750 6.9111 0.0100 0.0120 0.1000 N
2502 HAGER POND 16.6667 198.4666 1.5250 2.4050 248.2000 C
2503 HARRIS POND 29.8000 12.9500 0.0520 0.0700 7.5000 £
26A0 HOLLOWAY RESERVOIR 60.6250 10.6778 0.0570 0.0590 8.5000 E
26A 1 CARD RESERVOIR 27.0000 11.9667 0.1080 0.1175 2.7000 E
26A2 ROARDMAN HYDRO POND 136.5000 1.2667 0.0080 0.0060 0.1000 N
2603 ALLEGAN LAKE 29.1778 20.3111 0.1355 0.1115 16.8000 C
2606 BARTON LAKE 43.8333 27.8000 0.0610 0.1275 11.4000 E
2609 BELLEVILLE LAKE 34.7500 28.2625 0.1220 0.1145 23.5000 C
2610 BETSIE LAKE 38.3333 4.5667 0.0265 0.0220 3.5000 C
2617 LAKE CHARLEVOIX 148.7500 3.0083 0.0060 0.0070 0.1000 0
2621 CONSTANTINE RESERVOIR 43.8333 39.3167 0.0480 0.0275 8.7000 E
2629 FORD LAKE 43.8333 14.7333 0.1110 0.1100 14.6000 E
2643 KENT LAKE 45.0000 33.9444 0.0430 0.0420 8.2000 E
2648 LAKE MACATAWA 22.4000 25.6000 0.1590 0.2050 19.6000 E
2649 MANISTEE LAKE 48.6661 6.3161 0.0245 0.0170 1.0000 E
2665 PENTWATER LAKE 69.3333 36.0833 0.0270 0.0270 4.9000 E
2613 ROSS RESERVOIR 34.6667 30.3833 0.0350 0.0345 0.3000 E
2674 SANFORD LAKE 41.2500 13.7909 0.0180 0.0160 0.9000 E
2683 THORNAPPLE LAKE 57.1667 14.6500 0.0455 0.0430 4.5000 E
2685 UNION LAKE 44.5000 15.6667 0.0470 0.0030 2.7000 E
2688 WHITE LAKE 82.2222 9.2111 0.0265 0.0275 4.5000 E
2693 ST LOUIS RESERVOIR 37.3333 5.5833 0.2860 0.1200 23.4000 C
2694 CRYSTAL LAKE 120.0000 2.9857 0.0090 0.0090 0.1000 N
2696 HOUGHTON LAKE 19.1667 9.2167 0.0160 0.0180 0.2000 N
2697 THOMPSON LAME 92.1111 11.9667 0.0410 0.0420 2.9000 E
2698 PERE MARQUETTE LAKE 51.3333 11.8333 0.0300 0.0340 5.5000 E
2741 WINONA LAKE 20.8333 58.5500 0.1070 0.1100 16.6000 E
2745 ZUMBRO LAKE 59.0000 12.4667 0.4015 0.3100 47.3000 E
27A7 ST CROIX LAKE 43.6667 10.2464 0.0550 0.0300 3.4000 E
2782 GREEN LAKE 109.8333 4.8667 0.0150 0.0160 1.3000 N
27B4 DARLING LAKE 100.6667 11.8333 0.0170 0.0170 0.8000 C
2785 LE HOMME DIEU 91.1111 12.4444 0.0195 0.0160 0.2000 E
2799 LAKE CARLOS 111.7500 4.6333 0.0130 0.0130 0.9000 H
27C3 COTTONWOOD LAKE 13.5000 135.5249 0.0875 0.0820 7.7000 E
2705 BARTLETT LAKE 20.0000 49.4667 0.1365 0.1170 10.0000 E
2706 BEAR LAKE 11.0000 61.2333 0.1760 0.0660 2.0000 E
2111 BLACKDUCK LAKE 67.6667 14.5500 0.0430 0.0380 2.1000 E
2750 MADISON LAKE 33.8333 30.8000 0.0505 0.0450 3.8000 E
2752 MALMFOAL LAKE 14.5000 41.0000 0.1255 0.0625 7.4000 E
2760 LAKE MINNETONKA 54.1667 16.5791 0.0470 0.0560 2.1000 E
2786 SUPERIOR BAY 22.3333 6.2000 0.0790 0.0515 2.3000 E
3305 GLENN LAKE 65.5000 3.7833 0.0240 0.0400 0.1000 E
3306 KELLY FALLS POND 69.6667 7.0333 0.0285 0.0350 0.6000 E
3604 CANANOAIGUA LAKE 176.7500 4.3333 0.0090 0.0070 0.1000 o
3606 CARRY FALLS RESERVOIR 88.8333 3.0667 0.0100 0.0110 0.2000 H
3607 CASSADAGA LAKE 303.3333 9.7000 0.0260 0.0320 4.4000 C
160R LAKE CAYUGA 111.6364 3.2364 0.0145 0.0090 0.1000 H
3611 CROSS LAKE 53.3333 19.4667 0.0765 0.0730 3.2000 E
3613 GOODYEAR LAKE 74.0000 7.4500 0.0260 0.0310 0.3000 E
-------
LAKE MEAN MEAN MEDIAN MEDIAN TROPHIC
CODE LAKE NAME SECCHI CLOR—A TP(YR) TP(FALL) AA YIELD STATE
3615 HUNTINGTON LAKE 138.0000 6.4000 0.0150 0.0150 2.1000 E
3617 KEUKA LAKE 140.6667 5.6500 0.0080 0.0080 0.5000 M
3619 LONG LAKE 116.1667 3.4667 0.0080 0.0080 0.1000 0
3625 OTTER LAKE 45.0000 13.3333 0.0430 0.0440 1.0000 E
3627 OWASCO LAKE 106.4000 8.5333 0.0090 0.0080 0.2000 M
3629 RAQUETTE POND 87.0000 1,8500 0.0100 0.0155 0.2000 M
3630 ROUND LAKE 46.0000 28.3333 0.0765 0.0820 18.4000 E
3632 SACANDAGA RESERVOIR 139.2222 4.8500 0.0090 0.0090 0.1000 M
3634 SCHROON LAKE 147.0000 2.0833 0.0040 0.0040 0.1000 0
3635 SENECA LAKE 157.1250 6.0667 0.0100 0.0080 0.1000 0
3637 SWINGING BRIDGE RESERVOI 51.3333 28.6667 0.0570 0.0310 13.0000 E
3640 LOWER ST REGIS 76.5000 13.3833 0.0170 0.0225 0.6000 E
3641 ALLEGHENY RESERVOIR 51.3333 12.6000 0.0250 0.0530 10.4000 E
4402 SLATERSVILLE RESERVOIR 53.0000 8.1000 0.0340 0.0325 0.1000 E
5001 CHAMPLAIN LAKE 91.5366 11.0609 0.0180 0.0160 1.4000 M
5002 CLYDE POND 67.6667 7.5000 0.0210 0.0210 0.2000 E
5005 HARRIMAN RESERVOIR 111.0000 1.7667 0.0095 0.0080 0.1000 M
5007 LAHOILIE LAKE 58.6667 3.5400 0.0180 0.0190 1.9000 E
5010 LAKE ARROWHEAD 63.0000 8.4833 0.0150 0.0170 0.2000 E
5011 WATERBURY RESERVOIR 94.1667 5.2400 0.0070 0.0060 0.1000 M
5510 CASTLE ROCK FLOWAGE 30.1111 25.4555 0.0620 0.0480 1.7000 E
5532 OCONOMOWOC LAKE 114.6667 3.0667 0.0120 0.0140 0.2000 E
5534 PETENWELL FLOWAGE 27.8889 17.6000 0.0640 0.0540 3.4000 E
5535 PIGEON LAKE 34.6667 5.0000 0.0590 0.0465 12.9000 E
5546 TAINTER LAKE 54.5555 13.6667 0.1110 0.0990 16.8000 E
5550 WAPOGASSET LAKE 71.0000 16.6000 0.0435 0.0390 5.5000 E
5551 LAKE WAUSAU 28.6667 5.0000 0.0595 0.0410 1.5000 E
5555 WISCONSIN LAKE 31.7778 51.3666 0.0580 0.0555 12.0000 E
5558 OKAUCHEE LAKE 75.2000 8.3500 0.0160 0.0165 3.5000 E
5560 BROWNS LAKE 79.3333 6.4000 0.0220 0.0220 0.8000 E
5562 LAKE COMO 20.3333 36.4000 0.0480 0.0340 0.3000 E
5563 LAC LA BELLE 80.3333 7.9333 0.0130 0.0140 0.2000 E
5564 POCK LAKE 91.3333 8.1333 0.0130 0.0170 0.3000 E
5565 BIG EAIJ PLEINE RESERVOIR 32.0000 35.4666 0.0710 0.0795 15.2000 E
5566 ROUND LAKE 133.6667 3.5333 0.0110 0.0100 0.2000 E
5569 MIDDLE LAKE 141.3333 4.7333 0.0110 0.0125 0.2000 E
5570 GRAND LAKE 22.4000 65.3199 0.1900 0.0920 13.8000 E
5571 CRYSTAL LAKE 316.0000 1.5000 0.0070 0.0070 0.2000 0
5572 TROUT LAKE 162.0000 2.6833 0.0090 0.0090 0.7000 M
5573 LONG LAKE 34.8333 7.0500 0.0395 0.0370 0.1000 E
5575 ELK LAKE 36.6667 7.1333 0.0380 0.0330 2.8000 E
5581 SUPERIOR BAY 26.0000 15.8000 0.0605 0.0515 2.3000 E
-------
APPENDIX B
-------
DATA FOR FIGURE 5
Storet #
3302
3303
3306
4402
2503
2306
2308
2309
2310
2313
2314
5519
5539
5551
5570
5573
5574
5575
5002
5007
5008
5010
5011
Lake Name &
( Trophic State )
Powder Mill Pond (E)
Winnipesaukee (0)
Glenn (E)
Slatersville (E)
Harris Pond CE)
Long (M)
Mattawamkeag (M)
Moosehead (0)
Rangeley (0)
Long (M)
Bay of Naples (0)
Green (M)
Shawano CE)
Wausau (E)
Grand (E)
Long (E)
Willow (E)
Elk (E)
Clyde Pond (E)
Lamoille (E)
Memphremagog (E)
Arrowhead CE)
Waterbury (M)
Mean depth (m)/
Retention Time (yrs )
133.3
3.3
850.0
171.4
142.0
8.7
33.6
5.5
5.1
4.2
60.0
1.5
2.1
450.0
40.0
82.9
14.1
360.0
340.0
566.7
9.1
320.0
56.4
P Lo ding
( g/m /yr )
3.25
0.013
26.42
4.69
11.10
0.14
0.60
0.08
O .09
0.12
0.052
0.92
0.07
28.68
8.70
4.44
0.47
18.39
7 .09
22.87
O .46
10.55
1.23
-------
DATA FOR FIGURE 5
(Page 2)
Lake Name & Mean depth Cm)! P Lo ding
Storet # ( Trophic State) Retention Time (yrs) ( g/m /yr )
3609 Champlain (M) 7.5 0.52
2606 Barton (E) 27.7 21.80
2617 Charlevoix (0) 5.23 0.12
2618 Chemung (E) 2.03 0.22
2629 Ford (E) 109.0 5.29
2648 Macatawa (E) 19.9 6.35
2674 Sanford (E) 119.6 3.91
2683 Thornapple (E) 142.3 9.29
2685 Union (E) 182.0 9.27
2696 Houghton (M) 1.78 0.05
27B2 Green (M) 1.73 0.09
27B5 Le Homine Dieu CE) 0.81 0.12
27B9 Carlos (M) 3.54 0.14
3604 Canandaigua (0) 2.6 0.013
3608 Cayuga (M) 4.81 0.058
3634 Schroon (0) 34.1 0.39
3637 Swinging Bridge (E) 53.4 7.07
3605 Cannonsville (E) 33.4 4.26
2311 Sebago (0) 5.7 0.08
O - Oligotrophic
M - Mesotrophic
E - Eutrophic
-------
DATA FOR FIGURES 6 and 7
All Lakes Eutrophic and Nitrogen Limited
Storet #
0901
0903
0905
0911
0910
3305
4403
2304
2312
5502
5503
5508
5509
551 3
5515
5520
5522
5531
5535
5538
Lake Name
Aspinook Pond
Coimiunity Lake
Hanover Pond
Lillinoah
Zoa r
Kelley’s Falls Pond
Turner Reservoir
Estes
Sebasti cook
Al toona
Beaver Dam
Butte Des Morts
Butternut
Del avan
Eau Claire
Kegonsa
Koshkonong
Nagawi cka
Pigeon
Poygan
Mean Depth/Ret’n Time
( meters/years )
85.5
244.0
685.0
337.0
535.0
575.0
75.0
100.0
11.1
150.0
3.57
90.0
10.5
2.5
77.8
13.7
22.7
6.7
75.0
52. 5
P Lo ding
( g/m /yr )
8.4
337.0
228.9
24.9
41 .3
17.79
58.59
9.65
0.68
20.6
0.9
9.60
0.64
1.1
9.0
1 .85
9.87
1.33
6.45
5.55
N Lo ding
( g/m /yr )
94.9
1,742.0
1,405.0
335.2
723.8
525.6
216.9
110.29
16.3
224.7
10.1
181 .1
13.9
8.7
119.6
27.9
72.4
24 .1
160.2
94. 2
-------
DATA FOR FIGURES 6 and 7
(Page 2)
; toret #
545
546
5548
5550
5554
5555
5556
5559
5565
5577
5541
2603
2609
2631
2640
2643
2659
?6 71
2688
2691
2692
2699
Lake Name
Swan
Tai nter
Town line
Wapogasset
Winnebago
Wisconsin
Wissota
Tichigan
Big Eau Pleine
Beaver Dam
Si nissi ppi
Allegan
Belleville
F remo n t
Jordan
Kent
Muskegon
Randall Lake
White
Mona
Long
Strawberry
Mean Depth/Ret’n Time
( meters/years )
19.8
376.7
5.4
9.8
7.0
180.0
152.0
34.6
350.0
107.1
26.6
176.3
88.4
5.29
8.79
22.8
111.3
48.9
43.85
18.9
61 .6
186 .9
P Lo ding
( g/m /yr )
2.78
19.61
1.39
0.71
8.35
15.0
7 .64
20.51
1 .52
0.88
6.35
31 .3
15.73
2 . 97
1.14
1 .60
6.81
4.0
2.08
5 .97
4.62
9.18
N Lo ding
( g/m /yr )
39.5
223.4
9.4
11.1
134.0
246.8
219.9
91.2
22.98
10.1
62.1
403.4
217 . 1
16.4
29.3
22.7
109 .5
123.4
53.9
49.8
86.8
224.8
-------
DATA FOR FIGURES 6 and 7
(Page 3)
Mean Depth/Ret’n Time P Lo ding N Lo ding
Storet # Lake Name ( meters/years) ( g/m /yr) ( g/m /yrl
27A1 Winona 0.92 1.65 6.9
27A2 Wolf 85.30 6.43 60.3
27B1 Wagonga 0.92 4.0 16.0
27B3 Nest 8.83 0.79 16.4
27C0 Andrusia 61.2 4.02 59.1
27C1 Bemidji 13.3 0.44 13.4
2702 Albert Lea 5.50 6.31 61.2
2704 Badger 4.05 0.63 10.6
2711 Blackduck 1.07 0.14 2.6
2719 Cokato 6.74 2.6 27.4
2725 Elbow 3.87 7.89 31.2
2731 Fanny 9.68 15.0 30.6
2752 Malmedal 1.38 0.27 4.79
2757 McQuade 17.30 1.2 36.5
2765 Pelican 0.73 0.06 2.0
2777 Sakatah 17.36 3.74 57.7
2782 Silver 0.54 0.075 4.2
2793 Trout 0.87 0.33 2.8
2783 Sixmile 17.9 6.28 49.78
------- |