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LAKE SURVEY \` MAP
Osprey Lake Water Quality Study
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Prepared by:
Daniel D. Tyrolt
LCO Conservation Department
Phone: 715-634-0102 x124
ddtyrolt@cheqnet.net
March 1, 2005
Acknowledgments
The Osprey Lake water quality study was completed by the Lac Courte Oreilles Conservation f
Department. Thanks to Kristine Maki of the Lac Courte Oreilles Conservation Department for
determining the wetland acreage within the Osprey Lake watershed. Thanks to Tim Seidl of the
Sawyer County Land and Water Conservation Department for determining the agricultural acreage I
within the Osprey Lake watershed. Thanks to Brett McConnell of the Lac Courte Oreilles
Conservation Department for collecting the lake and stream data and summarizing the data in tables.
This report summarizes the results of a water quality investigation of Osprey Lake. Basic in -lake and
tributary water quality data were collected from April through September of 2004 to determine the
J existing conditions of the lake. This data was then used to estimate annual hydrologic and
phosphorus budgets for the lake in order to examine the relationship between watershed land use
activities and lake water quality. Zooplankton data was also collected periodically from June to
j September to help gain a better understanding of the biological community in the lake.
In the preparation of this report, it was necessary to estimate the yields of water and phosphorus to
the lake from various watershed land use activities using export rate coefficients extrapolated from
other studies. These coefficients represent the annual mass loading of water or phosphorus to the
lake per unit of a source (i.e., cubic meters of water or pounds of phosphorus per acre of forested
land). Selection of these coefficients was done by carefully screening a range of values for each
watershed land use activity and selecting the values that seemed most appropriate given the existing
watershed conditions. The suitability of the selected export rate coefficients for phosphorus was
further evaluated in terms of how well they predicted in -lake water quality conditions when used in
a phosphorus mass balance model. However good these model predictions are, they result from an
estimation process that involves the best professional judgement of the modeler. Being mindful of
the limitations associated with the estimation procedures used in this study, it is my professional
opinion that the estimated hydrologic and phosphorus budgets prepared for this study are reasonably
accurate in portraying the relative contributions to Osprey Lake's total annual phosphorus budget
from its constituent sources.
Executive Summa
The study described by this report was initiated by the Lac Courte Oreilles (LCO) Conservation
Department to assess the existing water quality of Osprey Lake. The study involved collection of
data from Osprey Lake and its watershed during 2004. Annualized hydrologic and phosphorus
budgets were then modeled for existing watershed land use conditions using the collected data.
The water quality data show that Osprey Lake has good water quality that would be consistent with
a north temperate oligotrophic lake. Total phosphorus and chlorophyll -a averages were within the
oligotrophic category (low productivity and no recreational use impairments) while the Secchi disk
average was within the mesotrophic category (moderate productivity, accumulated organic matter,
occasional algal bloom, minimal recreational use impairments). All of the annual summer averages
were on the borderline between oligotrophic and mesotrophic indicating that a slight change in water
quality conditions could change the trophic status ofthe lake. Summer Secchi disk readings averaged
14.9 feet, summer total phosphorus readings averaged 9.9 ug/L, and summer chlorophyll -a readings
averaged 1.96 ug/L. The seasonal pattern of chlorophyll -a, total phosphorus and Secchi disk readings
were similar through most ofthe monitoring period indicating that the lake's algal growth is directly
related to the phosphorus levels in the lake.
The zooplankton data show that from June to September Osprey Lake had lower than average
zooplankton density, with only two dates (early June and mid -August) having densities greater than
150 animals/feet'. There were few trends in individual taxa during the summer, except Calanoid
copepods, which in general declined from June to September. Diversity was also fairly consistent
across the sampling dates and near average compared to other lakes in the area. Productivity,
according to the Gannon Index was near average at the beginning of the sampling period, but
increased from June to September. Small cladocerans dominate over larger species on all dates
except the first sample in June, indicating that size selective predation (SSP) by fish may be an
important factor in shaping the plankton assemblage. Only in June were there more Daphnia than
Boswina in Osprey Lake, again showing the dominance of smaller species and pointing to possibly
greater food quality after early June. Compared to other lakes in the area during August, Osprey
Lake had near average total zooplankton density and diversity, high productivity, and possibly high
SSP.
The phosphorus budget modeling indicated that the total annual phosphorus loading to Osprey Lake
was 367 pounds, based on 2004 data. The inflow water from Osprey Creek contributed the largest
amount ofphosphorus at 149 pounds (40%). The next largest source was the forested portion ofthe
watershed which contributed 103 lbs of phosphorus which is 28% of the total loading. The wetlands
were estimated to contribute 18 lbs (5%). By applying a wet and dry atmospheric deposition rate of
0.25 lbs/acre/yr to the surface of Osprey Lake, the atmospheric component ofthe phosphorus loading
is computed to be 52 lbs or 14%. Residential use and septic systems contribute 12 lbs (3%) and 7 lbs
(2%) of the annual load respectively. The pasture/grassland contributed 11 pounds (3%). The
computations reveal that internal loading contributes 15 lbs (4%) of the total phosphorus load.
The impacts of cultural eutrophication on Osprey Lake were estimated by modeling pre -development
in -lake phosphorus concentrations and comparing the estimated pre -development concentrations with
current phosphorus concentrations (i.e. post -development conditions). Cultural eutrophication
describes the acceleration of the natural eutrophication process caused by human activities. An
assessment of the land uses within the Osprey Lake watershed indicate that there are two types of
land uses that contribute to cultural eutrophication. These land uses are:
1. PastureAGrassland-- The total loading from pasture/grassland is estimated to be 3.1 % of the
total phosphorus loading to Osprey Lake.
2. Residential - residential land use is comprised of the households within the direct watershed
and the septic systems located around the lake shore. The total phosphorus loading to the
direct watershed from residential land use is estimated to be just over 5% of the total
phosphorus loading.
The impacts of cultural eutrophication within the direct watershed on Osprey Lake were estimated
by modeling pre -development in -lake phosphorus concentrations and comparing the estimated pre -
development phosphorus concentrations with current phosphorus concentrations (i.e. post -
development conditions). Four modeling scenarios were completed to assess the impacts of cultural
eutrophication. The four scenarios consisted of the following:
1. Estimating the in -lake phosphorus concentration assuming forested land use (i.e. pre -
development condition) in place of pasture/grassland land use (i.e. current or post -
development condition).
2. Estimating the in -lake phosphorus concentration assuming forested land use (i.e. pre -
development condition) in place of residential land use (i.e. current or post -
development condition).
3. Estimating the in -lake phosphorus concentration assuming forested land use (i.e. pre -
development conditions) in place of pasture/grassland and residential land uses (i.e.
current or post -development conditions).
4. A large subdivision is being planned along the shoreline of the lake. The total
proposed development encompasses approximately 200 acres. The current land use
along this shoreline is forested. The current forested land use will be replaced by
residential land use and the resulting increase in the total phosphorus concentration
will be estimated.
The model indicates that the assumed conversion of forested land use to agricultural land use results
in a 0.2 ug/L (2%) increase in the total in -lake phosphorus concentration. This increase in
phosphorus does not result in a noticeable water quality change. The estimated 0.2 ug/L increase in .
total phosphorus concentration does not result in a noticeable decrease in the average annual Secchi
►1 .:ii
disk transparency. This is based upon the regression relationship between total phosphorus and
Secchi disk depth as determined from the 2004 sampling data for Osprey Lake. The predicted
decrease in Secchi disk depth would be an overall reduction in water clarity of less than 1% based
upon the 2004 average summer Secchi disk depth of 14.9 feet.
The model indicates that the assumed conversion of forested land use to residential land use results
in a 0.4 ug/L (4%) increase in the total in -lake phosphorus concentration. This increase in
phosphorus does not result in a noticeable water quality change. The estimated 0.4 ug/L increase in
total phosphorus concentrations results in an estimated decrease in the average annual Secchi disk
transparency of only two inches. The two inch decrease in Secchi disk depth correlates to a 10;0
decrease in the water clarity based upon the 2004 average summer Secchi disk depth of 14.9 feet.
The model indicates that the assumed conversion of forested land use to agricultural and residential
uses results in a 0.6 ug/L (6%) increase in the total in -lake phosphorus concentration. This increase
in phosphorus does not result in a noticeable water quality change. The estimated 0.6 ug/L increase
in total phosphorus concentration results in an estimated decrease in the average annual Secchi disk
transparency of 1.5 inches. This predicted decrease in Secchi disk depth would be an overall
reduction in water clarity of 2% from pre -development levels based upon the 2004 average summer
Secchi disk depth of 14.9 feet.
The model indicates that the proposed 200 acre development would result in a 2.85 ug/L (29%)
increase in the total in -lake phosphorus concentration. This increase in phosphorus would result in
a noticeable water quality change. The estimated 2.85 ug/L increase in total phosphorus
concentration results in an estimated decrease in the average annual Secchi disc transparency of 1.4
feet or 16.5 inches. This is based upon the regression relationship between total phosphorus and
Secchi disk depth as determined from the 2004 sampling data for Osprey Lake. This predicted
decrease in Secchi disk depth would be an overall reduction in water clarity of 9% based upon the
2004 average summer Secchi disk depth of 14.9 feet.
Long-term data going back to 1998 was available for Secchi Disk readings. Data was also available
dating back to 2000 for total phosphorus and chlorophyll -a. The historical data was collected at the
deep hole by LCO Conservation Department personnel. An. evaluation of the historic total
phosphorus, chlorophyll -a and Secchi disk monitoring data indicates that no statistically significant
trends exist over the time frame for which data is available. The differences in total phosphorus,
chlorophyll -a and Secchi disk values can be attributed to natural variation.
The annual summer Trophic State Index (TSI) values indicate that water clarity is typically better than
what would be expected based upon the total phosphorus and chlorophyll -a- readings. Even though
the TSI values were not the same for all of the parameters, they tended to follow the same general
pattern, once again suggesting that the lake is phosphorus limited.
The development of a comprehensive lake management plan for Osprey Lake is recommended in
order maintain and possibly improve the existing status ofthe water quality. This plan should include:
1. The development of long-term water quality goal for the lake;
2. An evaluation of different watershed development scenarios to determine acceptable
(i.e., the water quality ofthe lake is within the established goal) and unacceptable (i.e.,
the water quality of the lake fails to meet its goal) development options;
3. Recommendations for watershed best management practices under future
development conditions;
4. Recommendations for ordinances to control watershed development;
5. Recommendations for the riparian owner management practices;
6, Recommendations for best management plans to protect sensitive lands including
wetlands, steep slopes, undeveloped land, shoreline, etc.;
7. Algal study to determine species abundance and distribution;
8. A macrophyte study to determine the spatial coverage, density, and species
composition of the macrophyte community. A special area of concern would be
identification of Eurasian Water Milfoil.
9. Monitoring for Zebra mussels. Zebra mussel vellegers were discovered in 2004 to be
present in Round Lake. The water from Round discharges into Osprey Lake which
would- therefore place Osprey Lake into a high risk category for Zebra mussel
infestation.
iv
Osprey Lake Water Quality Study
Table of Contents
Executive Summary .................................................... i
Introduction1.0................................................. ....1
1.1 Report Coverage ................................ ......... 1
2.0 General Concepts in Lake Water Quality ................................. 2
2.1 Eutrophication............................................ 2
2.2 Trophic States ............................................ 2
2.3 Limiting Nutrients ......................................... 3
2.4 Nutrient Recycling and Internal Loading ......................... 5
2.5 Stratification ............................................... 5
2.6 Riparian Zone ............................................. 6
2.7 Watershed ............................................... 6
2.7.1 Water Quality Impacts of Various Land Uses In the Tributary
Watershed......................................... 7
2.8 Zooplankton.............................................. 7
3.0 Methods......................................................... 8
3.1 Lake Water Quality Data Collection ............................ 8
3.2 Lake Level Monitoring ..................................... 10
3.3 Precipitation Monitoring .................................... 10
3.4 Inflow Monitoring Methods ................................. 10
3.5 Outflow Monitoring Methods ................................ 10
3.6 Evaluation of the Vatershed................................. 10
3.7 Phosphorus and Hydrologic Budgets .......................... 14
3.7.1 Annualized Hydrologic Budget Calculations ............... 14
3.7.2 Annualized Phosphorus Budget ......................... 16
3.8 Z ooplankton............................................. 19
3.8.1 Collection and Counting Methods ....................... 19
3.8.2 Summary Indices .................................... 20
4.0 Results and Discussion .............................................. 22
4.1 Compiled Data ........................................... 22
4.2 2004 Lake Water Quality Conditions ........................... 22
4.2.1 Phosphorus ........................................ 22
4.2.2 Chlorophyll -a ...................................... 22
4.2.3 Secchi Disk Transparency ............................. 24
4.2.4 Temperature Isopleth Diagram ............. . ...........
24
4.2.5 Dissolved Oxygen Isopleth Diagram .. - ..................
27
4.2.6 Total Dissolved Solids and Specific Conductance Isopleth Diagrams
.............................
27
4.2.7 pH Isopleth Diagrams ...............................
27
4.2.8 Alkalinity Data .....................................
32
4.2.9 Current Trophic State Indices ..........................
32
4.3
Rainfall, Evaporation and Lake Level Data ......................
34
4.4
Inlet Data ...............................................
34
4.5
Zooplankton Data .........................................
35
4.6
Hydrologic Budget Calculations ..............................
37
4.7
Phosphorus Budget and Lake Water Quality Mass Balance Model ....
40
4.8
Cultural Eutrophication Impacts on Osprey Lake .................
40
5.0 Evaluation of Historical Water Quality Data ............................. 46
6.0 Recommendations and Management Actions ............................. 51
References.......................................................... 52
List of Tables
Table 1: Trophic Status and TSI Ranges ....................................
3
Table 2: Osprey Lake Water Quality Parameters ..............................
8
Table 3: Osprey Lake Direct Watershed Land Uses and Acreage .................
14
Table 4: Osprey Lake Land Use Phosphorus Export Coefficients .................
18
Table 5: Osprey Lake Trophic State Indices .................................
32
Table 6: Osprey Lake Zooplankton Density .................................
36
Table 7: Osprey Lake Zooplankton Summary Indices .........................
37
List of Figures
Figure 1: Carlson's Trophic State Index ..................................... 4
Figure 2: Osprey Lt_l:j Sampling, Inlet and Cutlet Locations ..................... 9
Figure 3: Osprey Lake Inflow Rating Curve ................................. 11
Figure 4: Osprey Lake Outflow Rating Curve ............................... 12
Figure 5: Osprey Lake Direct Watershed ................................... 13
V1-1
Figure 6: Osprey Lake Direct Watershed Land Use ...........................
15
Figure 7: Osprey Lake 2004 Total Phosphorus Concentrations ..................
23
Figure 8: Osprey Lake 2004 Chlorophyll -a- Concentrations .....................
25
Figure 9: Osprey Lake 2004 Secchi Disk Readings ...........................
26
Figure 10: Osprey Lake 2004 Temperature Isopleths ..........................
28
Figure 11: Osprey Lake-2004 Dissolved Oxygen Isopleths ......................
29
Figure 12: Osprey Lake Specific Conductance Isopleths .......................
30
Figure 13: Osprey Lake 2004 Total Dissolved Solids Isopleths ..................
31
Figure 14: Osprey Lake 2004 pH Isopleths.................................
33
Figure 15: Estimated 2004 Osprey Lake Inflow Budget ........................
38
Figure 16: Estimated 2004 Osprey Lake Outflow Budget ......................
39
Figure 17: Osprey Lake 2004 Annual Phosphorus Loading (%) ..................
41
Figure 18: Osprey Lake 2004 Annual Phosphorus Loading (lbs) .................
42
Figure 19: Osprey Lake 2004 Total Phosphorus vs Secchi Depth .................
45
Figure 20: Osprey Lake Annual Average Summer Total Phosphorus Values ........
47
Figure 21: Osprey Lake Yearly Average Summer Chl-a Values ..................
48
Figure 22: Osprey Lake Yearly Average Summer Secchi Disk Values .............
49
Figure 23: Osprey Lake Annual Summer TSI Values ...........................
50
List of Appendices
Appendix A Osprey Lake 2004 Analytical Data
Appendix B Profiling Data
Appendix C Lake Level Data
Appendix D Precipitation Data (Hayward DNR Ranger Station)
Appendix E Inflow and Outflow Staff Gauge Data
Appendix F Inlet/Outlet Flow and Total Phosphorus Data Summary
vii
Introduction 1.0
Osprey Lake, located in Sawyer County, Wisconsin, is considered a unique and significant water
resource by the Lac Courte Oreilles Band ofLake Superior Chippewa Indians (LCO), Sawyer County
and the Wisconsin Department ofNatural Resources (WDNR). The lake is a soft -water drainage lake
located in the Couderay River watershed. Osprey Lake has an inlet stream from Little Round Lake
and an outlet flowing into Lac Courte Oreilles Lake. It has a surface area of approximately 208 acres
and a volume of approximately 2,546 acre-feet. The maximum depth is 32 feet. Approximately 31 %
ofthe lake is over 20 feet deep and 18% is less than 3 feet deep. The total shoreline ofthe lake spans
5.86 miles. The lake has a varied fishery which includes walleye, muskellunge, northern pike, panfish,
crappie, and small and largemouth bass. The lakeshore property owners, LCO tribal members and
the general public, via the public accesses, utilize the lake for a wide variety of activities, including
fishing, boating and viewing wildlife.
Due to the cultural and economic significance of this lake to the LCO Reservation and Sawyer
County, the LCO Conservation Department determined that a comprehensive monitoring program
was necessary to assess the current water quality status of Osprey Lake. Major shoreline
development is also planned to occur on this relatively undeveloped lake. Consequently, the LCO
Conservation Department initiated a water quality study.
The study included a data collection phase, the completion of an annualized phosphorous and
hydrologic budget, along with a watershed evaluation for the lake. This information can be used to
develop a management plan for Osprey Lake to help ensure that the integrity of the lake is protected
from the increased pressure on the lake•due to increasing development and recreational uses.
1.1 Report Coverage
This report will answer the following questions that apply to properly managing a lake:
1. What is the general condition of the lake?
2. Are there problems associated with the lake?
To answer the first question, this report begins with a description of the Osprey Lake watershed, the
lake, and the methods of data collection and analysis. The results of the water quality monitoring are
then summarized in tables, figures, and accompanying descriptions.
To answer the second question, water quality data are analyzed and compared to established water
quality standards for lakes.
A background information section is also included in this report. Section 2.0 covers general concepts
in lake water quality.
There are many concepts and terminology that are necessary to describe and evaluate the water
quality and conditions of a lake. This section provides a brief discussion of the following topics:
♦ Eutrophication
♦ Trophic states
♦ Limiting nutrients
♦ Nutrient recycling and internal loading
♦ Stratification
♦ Riparian Zone
♦ Watershed
♦ Zooplankton
2.1 Eutrophication
Eutrophication, or lake degradation, is the accumulation of sediments and nutrients in a lake. As a
lake naturally ages and becomes more fertile, algae and weed growth increases. The increasing
biological production and sediment inflow from the lake's watershed eventually fills in the lake's
basin. The process of eutrophication is natural and results from the normal environmental forces that
influence a lake. Cultural eutrophication, however, is an acceleration of the natural process caused
by human activities. Nutrient and sediment inputs from agriculture, new construction, houses, septic
tanks, lawn fertilizers, and storm water runoff can far exceed the natural inputs to the lake. The
accelerated rate of water quality degradation caused by these pollutants results in unpleasant
consequences such as profuse and unsightly growths of algae (algal blooms), decreased water clarity
and/or the proliferation of rooted aquatic weeds.
The main cause of cultural eutrophication is uncontrolled development within a lake's watershed
and/or development without the use of Best Management Practices (BMP's). Creating and
implementing a lake management plan prior to the development of the lake's watershed is the best
way to try to prevent and minimize the impacts from cultural eutrophication.
2.2 Trophic States
Not all lakes are in the same stage of eutrophication because of varying nutrient status. Criteria have
been established to evaluate the existing nutrient "status" of a lake. Trophic state indices (TSI's) are
calculated for lakes on the basis of total phosphorus, chlorophyll -a concentrations, and Secchi disk
transparencies. A TSI value can be obtained from any one of those parameters. TSI values range
upward from zero, designating the condition ofthe lake in terms of its degree of fertility. The tophic
status indicates the severity of a lake's algal growth problems and the degree of change needed to
7
meet its recreational goals. Determining the trophic status of a lake is therefore an important step
in diagnosing water quality problems. Carlson's Trophic State Index is often used in interpreting
water quality data (see Figure I). For a general guideline, Table 1 should be referred to.
Table 1: Trophic Status and TSI Ranges
Trophic Status
TSI Range
Oligotrophic
TSI 37
Clear, low productivity lakes with total phosphorus concentrations
less than or equal 10 ug/L
Mesotrophic
38 TSI 50
Intermediate productivity lakes with total phosphorus concentrations
greater than 10 ug/L, but less than 25 ug/L
Eutrophic
51 TSI 63
High productivity lakes generally having 25 to 57 ug/L of total
phosphorus
Hypereutrophic
64 TSI
Extremely productive lakes that are highly eutrophic, disturbed and
unstable (i.e., fluctuating in their water quality on a daily and
seasonal scale, producing gases, off -flavor, and toxic substances,
experiencing periodic anoxia and fish kills, etc.) With total
2.3 Limiting Nutrients
The quantity of algae in a lake is usually limited by the water's concentration of an essential element
or nutrient. This is the "limiting nutrient." The limiting nutrient concept is a widely applied principle
in ecology and in the study of eutrophication. It is based on the idea that plants require many
nutrients to grow, but the nutrient with the lowest availability, relative to the amount needed by the
plant or algae, will limit it's growth.
Nitrogen (1) and phosphorus (P) are generally the two growth -limiting nutrients for algae in most
natural waters. Analysis of the nutrient content in lake water provides ratios ofN:P. By comparing
the ratio, one can estimate whether a particular nutrient may be limiting. Algal growth is generally
phosphorus -limited in waters with a N:P ratio greater than 15 (Byron, et. al.1997). It has been amply
demonstrated that phosphorus is usually the nutrient in limited supply in fresh waters. Therefore,
reducing phosphorus in the lake is required to reduce algal abundance and improve water
transparency. The failure to reduce the phosphorus concentrations entering the lake will allow the
process of accelerated eutrophication to continue.
3
Figure 1: Carlson's Trophic State Index
TSI < 30 Classic Oligotrophy: Clear water, oxygen throughout the year in the hypolimnion,
salmonid fisheries in deep lakes.
TSI 30 - 40 Deeper lakes still exhibit classical oligotrophy, but some shallower lakes will
become anoxic in the hypolimnion during the summer.
TSI 40 - 50 Water moderately clear, but increasing probability of anoxia in hypolimnion
during summer.
TSI 50 - 60 Lower boundary of classical eutrophy: Decreased transparency, anoxic hypolimnia
during the summer, macrophyte problems evident, warm -water fisheries only.
TSI 60 - 70 Dominance of blue-green algae, algal scums probable, extensive macrophyte
problems.
TSI 70 - 80 Heavy algal blooms possible throughout the summer, dense macrophyte beds, but
extent limited by light penetration. Often would be classified as hypereutrophic.
TSI > 80 Algal scums, summer fish kills, few macrophytes, dominance of rough fish.
01WW"phlc ' A4eswophlc l utmpkk Hxpereu mpk
Trophk
State index
15 1 u K 7 1; 5 •1 3 2 I. i 1 A r U.
Transparency
(m)
CWonnkfi-al
�Po)
Total
Plwsplrunis
(PPb)
ill i Al !a .il) 441 ul in) 84 11VI l ill
After Moore, L And K. Tlrornlon. ;fEd.] 1988. Lake and Reservoir Restoratlon Guidance. Manual
USEPA>EPA 4406,8&D02.
4
2.4 Nutrient Recycling and Internal Loading
Watershed runoff which includes overland flow and groundwater infiltration, or direct atmospheric
deposition are the two ways in which phosphorus can enter a lake. It would therefore seem
reasonable that phosphorus in a lake can be decreased by reducing these external loads ofphosphorus
to the lake. However, all lakes accumulate phosphorus, along with other nutrients, in the sediments
from the settling of particles and dead organisms. In some lakes this stored phosphorous can be
reintroduced into the lake water and become available again for plant uptake. This reintroduction
typically occurs during spring and fall turnover and in many cases is the cause for spring and fall algal
blooms. This release of the nutrients from the sediments to the lake water is known as "internal
loading". The amount of phosphorus coming from internal and external loads vary with each lake.
Internal loading can be estimated from depth profiles of dissolved oxygen and phosphorus
concentrations.
2.5 Stratification
The process of internal loading is dependent on the amount of organic material in the sediments and
the depth -temperature pattern, or "thermal stratification," of a lake. Thermal stratification has a
profound influence on a lake's chemistry and biology. As the ice melts and the air temperature warms
in the spring, lakes generally progress from being completely mixed to stratified with only an upper
warm well -mixed layer ofwater (epilimnion), and cold temperatures in a bottom layer (hypolimnion).
Because of the density differences between the lighter warm water and the heavier cold water,
stratification in a lake can become very resistant to mixing. When this occurs, generally in mid to late
summer, oxygen from the air cannot reach the bottom lake water and, if the lake sediments have
sufficient organic matter, biological activity can deplete the remaining oxygen in the hypolimnion.
The epilimnion can remain well -oxygenated, while the water above the sediments in the hypolimnion
becomes completely devoid of dissolved oxygen (anoxic). Complete loss of oxygen changes the
chemical conditions in the water and allows phosphorus that had remained bound to sediments to
reenter the lake water.
Phosphorus concentrations in the hypolimnion can continue to rise as the summer progresses until
oxygen is once again reintroduced. The dissolved oxygen concentration will increase if the lake
sufficiently mixes to disrupt the thermal stratification. Phosphorus in the hypolimnion is generally not
available for plant uptake because there is not sufficient light penetration into the hypoliinnion to
allow for plant growth or the growth of algae. The phosphorus, therefore, remains trapped and
unavailable to the plants until the lake is completely mixed again. In shallow lakes mixing can occur
frequently throughout the summer with sufficient wind energy. In deeper lakes only extremely high
wind energy is sufficient to destratify a lake during the summer and complete mixing only occurs in
the spring and fall. The cooling air temperature in the fall reduces the epilimnion water temperature
and consequently increases the density of water in the epilimnion. As the epilimnion water density
approaches the density of the hypolimnion water, very little energy is needed to cause complete
mixing of the lake. When this fall mixing occurs, phosphorus that has built up in the hypolimnion is
5
mixed with the epilimnetic water and some of it becomes available for algal growth. This is typically
the cause behind fall algal blooms. The remainder of the phosphorus combines with iron in the water
to form an amorphous ferric-hydroxy-phosphate complex that re -precipitates to the lake's bottom
sediments.
2.6 Riparian Zone
The riparian zone is extremely important to the lake and to the plants living there. Riparian
vegetation is that which is growing close to the lake and may be different from the terrestrial or
upland vegetation. The width of the riparian zone varies depending on many factors, including soils,
vegetation, slopes, soil moisture, depth of the water table, and even by location on the lake. For
instance, the north shore vegetation may provide little or no shade, while vegetation on the southern
shore may offer shade and cover well into the lake.
The riparian zone is important for the following reasons:
• Acts as a filter from outside impacts
■ Stabilizes the bank with an extensive root system
• Helps control or filter erosion
• Provides screening to protect visual quality and hides man's activities and buildings
• Provides the natural visual backdrop as seen from the lake
■ Provides organic material to the lake's food web.
• Offers cover and shade for fish and other aquatic life
• Provides valuable wildlife habitat
The riparian zone is the area most often impacted and riparian vegetation is lost when man enters the
scene. Cabins, homes, lawns, driveways, or other structures may replace native riparian vegetation.
Additional riparian vegetation may be eliminated to provide a larger view from the house or it may
be mowed and its value to the lake is lost.
The loss ofriparian vegetation results in the deterioration of many lake values besides water quality.
Wildlife habitat is lost, the scenic quality suffers, fish habitat is impacted, bank stability may be
weakened and the potential for erosion increases. The vegetation in the riparian zone filters
phosphorus and sediments from runoff water, which in turn protects the water quality of the lake.
2.7 Watershed
The area of land that drains to the lake is called the lake's watershed. This area may be small, as is
the case of small seepage lakes. Seepage lakes have no stream inlet or outlet and their watersheds
include only the land draining directly to the lake. On the other hand, a lake's watershed may be
large, as in drainage lakes such as Osprey Lake. Drainage lakes have both a stream inlet and an outlet
0
and therefore their watersheds include the land draining to the streams in addition to the land draining
directly to the lake. The water draining to a lake may carry pollutants that affect the lake's water
quality. Therefore, water quality conditions of the lake are a direct result of the land use practices
within the entire watershed. Poor water quality may reflect poor land use practices or pollution
problems within the watershed. Good water quality conditions suggest that proper land uses are
occurring in the watershed or there is minimal development within the watershed.
All land use practices within a lake's watershed impact the lake and determine its water quality.
Impacts result from the export of sediment and nutrients, primarily phosphorus, to a lake from its
watershed. Each land use contributes a different quantity of phosphorus to the lake, thereby,
affecting the lake's water quality differently. An understanding of a lake's watershed, phosphorus
exported from the watershed, and the relationship between the lake's water quality and it's watershed
must be understood.
2.7.1 Water Quality Impacts of Various Land Uses In the Tributary
Watershed
The impacts of various land uses on the water quality of Osprey Lake will be estimated by modeling
the water quality which would result from removing various land uses such as residential and
agriculture from the lake's annual phosphorus load. The estimated impacts of various land uses to
the water quality of Osprey Lake may be used by the LCO Conservation Department and other
agencies to estimate the potential water quality improvements which could result from the
implementation of Best Management Practices (BMP's) in the watershed.
2.8 Zooplankton
Zooplankton play a pivotal role in aquatic food webs because they are important food for fish and
invertebrate predators. Zooplankton communities are highly sensitive to environmental variation.
As a result, changes in their abundance, species diversity, or community composition can provide
important indications of environmental change or disturbance.
7
3.0 Methods
3.1 Lake Water Quality Data Collection
The 2004 sampling program involved the collection of water samples from the deep hole in the lake.
See Figure 2 for the location of the sampling station. The samples were collected approximately
weekly from the period of May through September. The sample consisted of a composite sample
from 0 - 6 feet. A sample of water was taken from the surface, three feet, and six feet below the
surface and mixed in a container to obtain the composite sample. The sampling dates spanned the
lake's period of elevated biological activity throughout the summer months and also correspond to
before and after spring and fall turnover. Field parameters and Secchi disk transparency were also
measured approximately weekly from May through September.
Table 2 indicates the water quality parameters that were measured at each station, and specifies at
what depth and how frequent the samples or measurements were collected. The dissolved oxygen,
temperature, specific conductance, total dissolved solids, pH, and Secchi disk transparency were
measured in the field; where as the water samples were analyzed in the laboratory for total
phosphorus and chlorophyll -a.
Table 2: Osprey Lake Water Quality Parameters
'Parameters
Depth (Meters)
Dissolved Oxygen
Surface to Bottom Profile
Temperature
Surface to Bottom Profile
Specific Conductance
Surface to Bottom Profile
Total Dissolved Solids
Surface to Bottom Profile
pI-1
Surface to Bottom Profile
Chlorophyll a
0-2
Secchi Disk
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3.2 Lake Level Monitoring
One staff gauge was installed in Osprey Lake on 10/16/03. The gauge was read periodically from the
installation date to 9/30/04. The lake level data was used in the determination ofthe lake's hydrologic
budget.
3.3 Precipitation Monitoring
Precipitation data recorded at the Lac Courte Oreilles Atmospheric Deposition Station (WI-97) was
used for the analysis of the hydrologic budget.
3.4 Inflow Monitoring Methods
Refer to Figure 2 for the location of the inlet. Seventeen grab samples were collected from the inlet
during the period of May through September. Five of these samples were taken after a storm event.
All samples were analyzed for total phosphorus. A staff gauge was installed at the inlet and read on
approximately a weekly basis from the middle of April through September. Discharge was also
measured during each sampling event and the discharge and staff gauge data were used to establish
a stage -discharge rating curve to predict the inlet's flows. See Figure 3 for the Osprey Lake inflow
rating curve.
3.5 Outflow Monitoring Methods
Refer to Figure 2 for the location of the outlet. Seventeen grab samples were collected from the outlet
during the period of May through September. Five of these samples were taken after a storm event.
All samples were analyzed for total phosphorus. A staff gauge was installed at the outlet and read
on approximately a weekly basis from the middle of April through September. Discharge was also
measured during each sampling event and the discharge and staff gauge data were used to establish
a stage -discharge rating curve to predict the outlet's flows. See Figure 4 for the Osprey Lake
outflow rating curve.
3.6 Evaluation of the Watershed
The total watershed of Osprey Lake encompasses 10,149 acres or 15.9 miles. This gives a
watershed basin to lake area ratio of 49:1. Of the 10,149 acres, only 1,449 acres drain directly into
Osprey Lake. This will be referred to as the direct watershed. See Figure 5 for the direct drainage
watershed for Osprey Lake. The remaining 8,700 acres consist of the Big and Little Round Lake
watersheds which drain into Osprey Lake via the inlet. The various land uses and their corresponding
10
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the percentages of the different land uses within the direct watershed.
Table 3: Osprey Lake Direct Watershed Land Uses and Acreage
Land Use
Acres
Pasture/Grassland
36
Medium Density Residential
16
Rural Residential
36
Wetlands
204
.Forest
1,157
Lake Surface ce Area
208
3.7 Phosphorus and Hydrologic Budgets
The nutrient balance of a lake is defined by the quantities of nutrients contributed to or removed from
the lake by various inflow and outflow routes and is analogous to and dependent upon the hydrologic
balance for the lake. It has been amply demonstrated that most often phosphorus is the nutrient that
Emits algal growth in lakes, as is the case in Osprey Lake. To develop an understanding ofthe pattern
ofphosphorus transport through Osprey Lake, monitoring data was combined with the results of the
hydrologic monitoring to develop an annualized hydrologic and phosphorus budget for the lake.
3.7.1 Annualized Hydrologic Budget Calculations
The hydrologic budget for Osprey Lake based on the 2004 water year (October 1, 2003 through
September 30, 2004) was calculated by measuring or estimating the important components of the
budget. The important components of the budget for Osprey Lake include:
Precipitation
• Runoff (overland flow and groundwater seepage)
• Evaporation
• Change in lake storage
Stream Inflow
Lakc i. aLfflo'vI
• Groundwater base flow
A mass balance approach was used to determine the annualized hydrologic budget for Osprey Lake.
14
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The general water balance equation used was:
AS=O+E-P-R-I+OGW
Where:
AS = change in lake storage volume
O = lake outflow
E = evaporation from the lake surface
P = direct precipitation on the lake surface
R = runoff: from the watershed
I = stream inflow
AGW = Net Groundwater Flow (Groundwater inflow - Groundwater outflow)
The precipitation data from the Lac Courte Oreilles Atmospheric Deposition Station was used to
determine direct precipitation on the lake's surface.
Evaporation from the surface of osprey Lake was estimated from pan evaporation rates obtained
]from the Marshfield Agricultural Research Center. An evaporation coefficient of 0.8 was used to
convert the pan evaporation to actual field evaporation. Evaporation for the winter months
(November - April) was assumed to be similar to the evaporation rates over the winter months
computed for a study on Lac Courte Oreilles Lake by Ban Engineering during 1995-96 (Barr
Engineering, 1998).
A staff- gauge was installed in Osprey Lake on 10/16/03. The gauge was read periodically from the
installation date to 9/30/04. The staffgauge reading was used to determine the lake volume changes.
The average runoff rate for Sawyer County Wisconsin was used as a basis for deternvning the runoff
rate for the Osprey Lake watershed. This value was adjusted to reflect the slightly below normal
amount ofprecipitation during the 2004 water year. The precipitation was approximately 3% below
the average precipitation, therefore the runoff was adjusted to be 3% lower than average also.
The net groundwater flow (inflow minus outflow) was estimated for the period from May through
September. The precipitation, change in storage, inflow, outflow, and the other parameters were
either known or estunated for that period using generally accepted practices. An average monthly
groundwater flow was then determined for that period. The average monthly flow was used to
compute an annual groundwater flow contribution.
3.7.2 Annualized Phosphorus Budget
The annualized phosphorus budget for Osprey Lake under existing land use conditions was estimated
with the assistance of a phosphorus mass balance model. The mathematical equations within the
model help to interpret the relationship between phosphorus loads, water loads and lake basin
16
characteristics to the observed in -lake total phosphorus concentration. The equation used to predict
the in -lake phosphorus concentration was adapted from one developed by Dillon and Rigler (1974)
and modified by Nurnberg (1984). This equation was added to the Wisconsin lake Model
Spreadsheet (WILMS) (Panuska and Wilson, 1994). It has the form of:
P= LA(7 - R) + L►
QT QS
Where:
P = Predicted lake mean total phosphorus concentration
LA = amount of phosphorus added per unit surface area of lake from all sources except
from the internal load of the lake
RP = annual phosphorus retention coefficient of the lake sediments [15/(18+QS]
QS = Lake outflow divided by its surface area
LI = mass of phosphorus per unit surface area of lake added to the lake from internal
loading
The watershed land use data and published phosphorus export coefficients, which are based on
watershed land use data, were used to determine phosphorus loading from the watershed. Water
quality data (i.e. collected from the lake) were used to calibrate the model.
The important components of the phosphorus budget for Osprey Lake include:
• Watershed surface runoff from agricultural, forested, residential and wetland land uses
Atmospheric wet and dry deposition on the lake surface
■ Septic system loading
Tributary loading
• Internal loading
The watershed surface runoffcomponents ofthe phosphorus budget were estimated using an assumed
phosphorus export coefficient for each land use type within the watershed of Osprey Lake. Table 4
lists the land use along with its corresponding export coefficient. All of the phosphorus export
coefficient values are within the ranges suggested by the WILMS model and generally agree with the
most likely default value suggested by the model (Panuska and Lilly, 1995).
17
1;I
Table 4: Osprey Lake Land Use Phosphorus Export Coefficients
Land Use
Export Coefficient
(lbs/acre)
Export Coefficient
(Kg/Ha)
Pasture/Grassland
0.31
0.53
0.35
:Medium Density Urban Residential
0.59
Rural Residential
0.11
0.12
Wetlands
0.09
0.1
'Forest
0.09
0.1
Lake Surface (atmospheric de sit'
0.25
.28
The internal loading for Osprey Lake was estimated using a complete total phosphorus (TP) mass
budget. The mass budget approach implicitly considers internal loading because the mass of '
phosphorus in the outflow is greater than that of the inflow in lakes with internal loading. A typical
phosphorus mass balance can be written as follows:
Outflow Pmass = External Load Pmass + Internal Load Pmass - Sedimentation
To calculate the internal load value Osprey lake is first assumed to be oxic. The phosphorus retention
coefficient to fit oxic lakes of R = 15/(18+q.,) is used to describe the percentage of phosphorus that
would be typically retained in the lake under oxic conditions. In this expression, R is the phosphorus
retention and q, is the water -loading rate in meters per year. Knowing the inflow phosphorus
concentration from external loadings, the average annual water column phosphorus concentration
which is assumed the same as the outflow P concentration, and the R as described above, the
additional phosphorus necessary to achieve the observed in -lake concentration can be determined.
This additional load is attributed to the internal loading.
Typically phosphorus has a chance to redissolve into the water column from the sediments when the
bottom water becomes anoxic, i.e., dissolved oxygen levels less than 0.5 mg/liter. Only a small
portion of the lake did fall below the 0.5 mg/L threshold. This occurred from about the middle of
July through the first week of August and for just a brief period during the middle of September.
During this time period, approximately only the bottom one foot of water became anoxic with the
potential of internal loading. A total of 38 pounds of phosphorus was redissolved into the
hypolimnetic water. The fraction ofthe hypolimnetic total phosphorus released to the surface waters,
which would now be available to algae for growth, was estimated to facilitate the calibration of the
model. The fraction of the total hypolimnetic phosphorus estimated to be released to the surface
waters was approximately 39% of the 38 pounds which would be 14.9 pounds.
18
The phosphorus export rate computations used inthe WILMS model were used to estimate an annual
load from the septic systems along Osprey Lake. The equation used to estimate the septic load was:
Total Septic System Load (Kg/yr) = Es, * # of capita-yrs * (I-SR)
ES, = export coefficient to septic tank systems (0.55 Kg/capita/yr)
capita-yrs = # of people occupying a dwelling each year
_ (# of permanent residents/dwelling)*(# of permanent
dwellings) + (# of seasonal residents/dwelling)*(days/yr)*(#
of seasonal dwellings)
SR = weighted soil retention coefficient (.83 for value used in
model)
A septic system survey which would inspect all of the properties along the lakeshore for failing
systems was not conducted on Osprey Lake. The following assumptions were used in determining
the loading to Osprey Lake from septic systems:
► 16 units along lakeshore contribute to septic load
► leachate from all of the systems flow into the lake
► 48% of residences are year round; 52% seasonal
► 3 persons/year-round residence; 5 persons/seasonal residence
► Seasonal dwellings occupied 100 days/yr
► 13.5% of systems assumed to be failing (this is the average number of failing
systems for surveys which were conducted on Lac Courte Oreilles and Round
Lakes in Sawyer County)
The accuracy ofthe phosphorus export coefficients to predict the phosphorus loading to the lake was
evaluated by comparing the predicted in -lake phosphorus concentration with the observed
concentrations of the samples which were collected. The modeled predicted total phosphorus
concentration was the same as the observed average epilimnetic (i.e., surface water or upper 6 feet)
total phosphorus concentration. The data therefore supports the annual phosphorus export
coefficients selected for the model.
3.8 Zooplaniton
3.8.1 Collection and Counting Methods
Zooplankton was sampled at the deep hole in the lake. Refer to Figure 2 for the sampling location.
The samples were collected using vertical tows, using a plankton net equipped with a 7:1 reducing
cone. Upon collection, samples were preserved in the field with ethanol.
19
The density estimates for each sample were based on (1) quantitative sub -samples of 100 specimens
for each of the common taxonomic groups and (2) searches of at least half the sample for the rare
taxonomic groups. Three major taxonomic groups, cladocerans, copepods, and rotifers, were
categorized and counted. Cladocerans were distinguished as Daphnia, Bosmina, Diaphanosoma,
Chydorus, Ceriodaphnia, Holopedium, or Leptodora kindti. Cladocerans are often referred to as
water fleas and vary between 0.2 and 3 mm in length. Cladocerans are common in northern
temperate lakes especially in the summer, and all but L. kindti are primarily herbivorous. Copepods,
a second major group of zooplankton, were distinguished as either Cyclopoid copepods or Calanoid
copepods for copepodid stages. Nauplii, immature copepods in the naupliar stage, were categorized
as copepod Nauplii. Copepods are observed in many lakes throughout the year and the copepodid
stages vary between 0.3 and 3.2 mm in length. Some copepods are planktivores, but most are
herbivores. Rotifers were the third major taxonomic group of zooplankton quantified. Rotifers are
ubiquitous in freshwater and are a highly diverse taxonomic group in both size (40µm to 2.5 mm) and
feeding ecology (herbivores, detritovores, and omnivores). In addition to the three major taxonomic
groups, Chaoborus and Chironomids were quantified. These are aquatic stages of insects found in
the plankton, which can be important predators on zooplankton. These invertebrate predators are
known to migrate into the sediments during the day to avoid visual predation by fishes and therefore
the data should be regarded as presence/absence information and not faithful density estimates.
Two density estimates are provided for each sample, the number of each taxonomic group per square
foot and the number of each taxonomic group per cubic foot. The later takes into account the depth
of the sampling site and is a common method to compare abundances across sites with different
depths. Areal density (the number of animals per square foot) is a more realistic estimate since for
these samples the position of the animals in the water column is unknown.
3.8.2 Summary Indices
For each sample collected four summary indices were calculated, the Shannon Diversity Index, the
Gannon Index, and two Cladoceran Size Indices. The Shannon Diversity Index was used to
determine the diversity of each sample. The Shannon Diversity index uses the number of taxonomic
groups and their relative abundance to estimate how much biological diversity is present at a site.
High values for the Shannon Index indicate a site with many taxonomic groups and relatively even
abundances. Low values indicate either few taxonomic groups or dominance by one group. Many
scientists use diversity as a measure of ecosystem health and condition. Systems with high diversity
are thought to be more resilient to external perturbations, such as an exotic species invasion or
environmental degradation. High values for Shannon Diversity Index indicate more diverse systems.
The Gannon Index (Gannon and Stremberger 1978) was used to compare the productivity or trophic
status of the sites sampled. This ratio is defined as the ratio of Calanoid copepod density to the sum
of Cyclopoid copepod density and cladoceran density. It is a general indicator of trophic status or
lake productivity since Calanoid copepods tend to be more dominant in low productivity lakes.
Although the value resulting from the Gannon Index does not give an absolute value that defines lake
-,A
productivity, it is useful in comparing the trophic status of multiple locations or sampling times in a
single lake or among different lakes. The productivity of lakes can vary between eutrophic conditions
(high nutrients and dense phytoplankton) to oligotrophic conditions (low nutrients and few
phytoplankton). If the Gannon Index is a smaller number, the productivity of a lake is high or tends
toward the more eutrophic side of the spectrum.
A size index was used comparing the density of small cladocerans (Bosmina, Ceriodaphnia, and
Chydorus) to the total density of cladocerans (adapted from Mills et al. 1987). Fish predation is
typically size selective because fish, which often are visual predators, select the larger prey items.
Invertebrate predators (such as L. kindti and Chaoborus), on the other hand, often prefer small prey
items. A high value for this size index might indicate that size selective predation (SSP) by fish is
intense and planktivorous fish are abundant.
The ratio of Daphnia to Bosmina was also calculated. This ratio, although helpful in assessing SSP,
is primarily an indication of food quality for herbivorous plankton. Bosmina are more selective
feeders who generally consume only high quality phytoplankton. Daphnia will tolerate lower quality
food items and even consume detritus. If Bosmina are ruore dominant than Daphnia, food quality
may be high. A high Daphnia to Bosmina ratio might indicate the predominance of lower quality
phytoplankton.
21
1
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4.0 results and Discussion
4.1 Compiled Data
Water quality data acquired during the 2004 monitoring program are compiled in Appendices A
through F. Appendix A presents the tabulated in -lake water quality. Appendix B contains the
profiling data.. Appendix C contains the lake level data used to determine changes in lake volume.
Appendix D contains the precipitation data obtained from the Lac Courte Oreilles Atmospheric
Deposition Monitoring Station (WI.97). Appendix E contains the inflow and outflow staff gauge
data and Appendix F contains a summary of the flows and total phosphorus data for the inlet and the
outlet.
4.2 2004 Lake Water Quality Conditions
4.2.1 Phosphorus
Phosphorus is the plant nutrient that most often limits the growth of algae.
Phosphorus -rich lake water indicates a lake has the potential for abundant algal
growth, which can lead to lower water transparency and a decline in hypolimnetic
oxygen levels in a lake.
While nitrogen can limit algal growth, it can be obtained from the atmosphere by
certain algal species. This is termed nitrogen fixation. Thus, phosphorus is the only
essential nutrient that can be effectively managed to limit algal growth.
The total phosphorus data collected from Osprey Lake during 2004 ranged from mesotrophie (i.e.
moderate amounts ofnutrients) to oligotrophic. The average summer total phosphorus concentration
of 9.9 uglL was just within the oligotrophic range as can be seen in Figure 7. Figure 7 also shows
how the total phosphorus levels changed throughout the monitoring period. Only a small increase
in the summer average total phosphorus concentration (less than 1 ug/L) would shift the trophic
status of Osprey Lake to mesotrophic instead of oligotrophic based on total phosphorus
concentrations.
4.2.2 Chlorophyll -a
Chlorophyll -a is a measure of algal abundance within a lake. High chlorophyll -a
concentrations indicate excessive algal abundance (i.e. algal blooms), which can
lead to recreational use impairment.
22
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The 2004 Osprey Lake chlorophyll -a data show that the average summer concentration of 1.96 ug/L
was just within the oligotrophic category (see Figure 8). Once again, just a small increase in chl-a
values would change the trophic status of the lake to mesotrophic based upon the chl-a values.
Figure 8 also shows how the chlorophyll -a concentrations changed throughout the monitoring period.
The seasonal pattern of chlorophyll -a was similar to the total phosphorus concentrations and Secchi
disk readings through most of the monitoring period, further indicating that the lake's algal growth
is directly related to the phosphorus levels in the lake.
4.2.3 Secchi Disk Transparency
Secchi disk transparency is a measure ofwater clarity. Perceptions and expectations
of people using a lake are generally correlated with water clarity. The results of a
survey completed by the Metropolitan Council (Osgood, 1989) indicated that the
following relationships can generally be perceived between a lake's recreational use
impairment and Secchi disk transparencies:
■ No impairment occurs at Secchi disk transparencies greater than 4
meters (13 feet).
Jr Minimal impairment occurs at Secchi disk transparencies of 2 to 4
meters (6.5 -13 feet).
■ Moderate impairment occurs at Secchi disk transparencies of I to 2
meters (3.3 - 6.5 feet).
■ Moderate to severe use -impairment occurs at Secchi disk
transparencies less than I meter (3.3 feet).
The Secchi disk measurements in Osprey Lake generally mirrored the total phosphorus and
chlorophyll -a concentrations. The average Secchi disk transparency reading of 14.9 feet was just
within the mesotrophic range (see Figure 9). Figure 9 also shows the pattern of the Secchi disk
reading throughout the monitoring period. The seasonal pattern of the Secchi disk values suggest
that the lake's water transparency was, for the most part, determined by the algal abundance.
4.2.4 Temperature Isopleth Diagram
Isopleth diagrams represent the change in a parameter relative to depth and time.
For a given time period, vertical isopleths indicate complete mixing and horizontal
isopleths indicate stratification. Isopleth diagrams are useful for showing patterns
with depth and time when sufficient depth profile data are available.
24
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The temperature isopleth diagram (Figure 10) prepared for Osprey Lake shows that the lake mixed
completely during the spring and fall (i.e. same temperature from top to bottom) and was generally
stratified from approximately June through September.
4.2.5 Dissolved Oxygen Isopleth Diagram
The dissolved oxygen isopleth diagram (Figure 11) indicates that most of the lake had stratified
dissolved oxygen concentrations from the end of May thru September. Oxygen depletion of the
bottom waters reduces the available habitat for organisms (i.e. fish and zooplankton). A dissolved
oxygen concentration of 5.0 mg/L is considered the minimum desirable level for fish. This level is
represented by the blue dashed line in Figure 11. Oxygen concentrations of at least 5.0 mg/L were
noted throughout the summer down to around twenty-two feet. If dissolved oxygen concentrations
fall below 0.5 mg/L, the water is considered anoxic (i.e. without oxygen) and phosphorus can re-
dissolve into the anoxic waters from the sediment. This is termed internal loading. Internal loading
did occur within Osprey Lake. The period of anoxia and subsequent likely internal loading is indicated
by the shaded area in Figure 11.
4.2.6 Total Dissolved Solids and Specific Conductance Isopleth Diagrams
Specific conductance is directly related to the amount of dissolved inorganic chemicals (minerals,
nutrients, metals, and other inorganic chemicals) in the water. Total dissolved solids provides another
measurement of materials dissolved in the lake. They both are a reflection of the soils and bedrock
in the lake's watershed and they also indicate the level of internal loading occurring within the lake.
Figure 12 represents the specific conductance isopleths and Figure 13 represents the total dissolved
solids isopleths. The total dissolved solids and specific conductance isopleths do show increasing
levels in the hypolimnion towards the end of August, once again indicating that some internal loading
is occurring during that time period. Lakes with higher specific conductance and total dissolved
solids are more productive waters, capable of supporting more aquatic plants and animals.
4.2.7 pH Isopleth Diagrams
pH defines the acid or alkaline status of the water. A pH of 7.0 is neutral, while
waters above 7.0 are alkaline, and waters below 7.0 are acidic. Rainwater is
naturally slightly acidic. Lakes that receive most of their water from precipitation,
such as seepage lakes, will be acidic. Drainage lakes receive most of their water
from streams and rivers and will tend to be more alkaline.
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The acidity or alkalinity ofa lake directly influences the aquatic life in the lake. For
example, if a lake has a pH of 6.5 or lower (acidic), walleye spawning is inhibited.
At a pH of 5.2 or lower, walleyes cannot survive. Acidic conditions may result in
higher mercury levels and may pose health problems to wildlife and humans
consuming fish.
The pH isopleth diagram for Osprey Lake indicates that alkaline conditions occurred throughout most
of the lake during the monitored sampling period (see Figure 14). The lake's surface waters tended
� to be slightly more alkaline than the deeper water, as is indicated by the higher pH levels.
Photosynthesis causes the addition of hydroxide ions to the water, resulting in higher pH levels.
Photosynthesis by algae in the lake's surface waters likely caused the increased pH levels, thereby
y resulting in higher levels than the lake's bottom waters. All ofthe pH levels measured in Osprey Lake
are within the range of values considered safe for fish and aquatic animals. The H values in Osprey
p P Y
Lake ranged from a high of 9.48 to a low of 6.75.
4.2.8 Alkalinity Data
Alkalinity is associated with the carbon system in the lake. Another term used to indicate
a lake's alkalinity is hardness. Hard water lakes (greater than 60 mg/L calcium carbonate)
tend to be better producers of aquatic life, including both plants and animals. Soft water
lakes (less than 60 mg/L calcium carbonate) are not as productive. Extremely low
alkalinities (less than 5 mg/L calcium carbonate) are more likely to be impacted by
acidification resulting from acid rain. Alkalinities above 5 mg/L calcium carbonate have
enough buffering to counteract the effects of acid rain. -
The average alkalinity for Osprey Lake is 32 mg/L calcium carbonate. Osprey Lake would therefore
be classified as a soft water lake.
4.2.9 Current Trophic State Indices
Table 5 indicates the trophic state index (TSI) for Osprey Lake based on the given parameter.
Table 5: Osprey Lake Trophic State Indices
Parameter
Value
Trophic State Index
Total Phosphorus
,Chlorophyll -a-
9.88 ug/L
1.96 ug/L
37
37
Secchi disk de121h
14.9 feet
38
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The TSI values for Osprey Lake correspond to the parameter readings taken between Memorial Day
and Labor Day, or the dates closest to these when samples were taken. The span of these dates
corresponds with typical summer conditions and peak recreational use of the lake and therefore
should most closely correlate with user perceptions of the lake. The TSI values indicate that Osprey
Lake is generally oligotrophic (refer to Figure 1 and Table 1). The TSI values indicate that Osprey
lake is very close to being classified as a mesotrophic lake. Only a small change in the water quality
would switch the lake into a different trophic classification.
4.3 Rainfall, Evaporation and Lake Level Data
As previously mentioned, rainfall data from the Lac Courte Oreilles Atmospheric Deposition
Monitoring Station was used for the study period. The total average precipitation during the 2004
water year was 29.54 inches. This is very close to the normal Northwest Wisconsin average
precipitation of 30.49 inches as determined by the Spooner, WI Experimental Farm.
Pan evaporation rates from the Marshfield Agricultural Experimental Research Station were used to
determine the surface evaporation from Osprey Lake. Since pan evaporation rates are higher than
actual lake evaporation, they must be adjusted to account for variances such as radiation and heat
exchange effects. The adjustment factor is termed the pan coefficient. A pan coefficient of 0.8 was
used for this study. The pan evaporation data did not cover the winter months i.e. (November -
April). Therefore, winter evaporation rates used by Barr Engineering for a similar study on Lac
Courte Oreilles Lake were used (Barr, 1998). Evaporation ranged from a high of 6.42 inches in July
to a low of0.12 inches for each month ofDecember, January and February. The total estimated lake
surface evaporation during the water year of 2004 was 24.51 inches. The average annual evaporation
rate for northwestern Wisconsin is 28 inches (Linsley, Jr. et al., 1982). The annual evaporation rate
for the study period was therefore 12% below normal.
One staff gauge was installed in Osprey Lake on 10/16/03. The gauge was read periodically from the
installation date to 9/30/04. The monitored lake surface elevations had a range of nearly seventeen
inches. The highest lake level observed during the monitoring period was on 9/23/04 with a reading
of 2.36 feet and the lowest level was observed on 10/29/03 with a reading of 0.96 feet.
4.4 Inlet Data
Discharge and total phosphorus concentration data were collected from the inlet. This data wasused
to determine the annual phosphorus input from the inlet. The total flow from the inlet was estimated
to be 4,983 acre-feet. This results in an estimated annual phosphorus loading to the lake of 149
lbs/year.
34
4.5 Zooplankton Data
Two density estimates are provided for each sample, the number of each taxonomic group per square
foot and the number of each taxonomic group per cubic foot (Table 6). The later takes into account
the depth of the sampling site and is a common method to compare abundances across sites with
different depths. Areal density (the number of animals per square foot) is a more realistic estimate
since for these samples the position of the animals in the water column is unknown.
T;o-• each c�n��,l; cnl?eeted, frnir s�immar'y indices `sere also calculated. These indices include the
Shannon Diversity index, the Gu non Index, and two Cladoceran Size Indices. These are compiled
in Table 7. A total density of zooplankton for each sample is also provided in Table 7. High values
for the Shannon Index indicate a site with many taxonomic groups and relatively even abundances.
Low values indicate either few taxonomic groups or dominance by one group. Low values for the
Gannon Index indicate lakes with high productivity. The size index is the density of small cladocerans
(Bosmina, Ceriodaphnia, and Chydorus) to the total density ofcladocerans. Low values for the size
index may indicate that size selective predation (SSP) is low, and when values are greater than 0.5,
SSP may be more intense. The Daphnia to Bosmina ratio (D/b) is a measure of food quality. When
the D/b ratio is greater than one, Daphnia are most dominant, and food quality may be poor. When
the ratio is less than one, Bosmina are dominant and food quality is likely to be intermediate or high.
From June to September Osprey Lake had lower than average zooplankton density, with only two
dates (early June and mid -August) having densities greater than 150 animals/feet3. There were few
trends in individual taxa during the summer, except Calanoid copepods, which in general declined
from June to September. Diversity was also fairly consistent across the sampling dates and near
average compared to other lakes in the area. Productivity; according to the Gannon Index was near
average at the beginning of the sampling period, but increased from June to September. Small
cladocerans dominate over larger species on all dates except the first sample in June, indicating that
SSP by fish may be an important factor in shaping the plankton assemblage. Only in June were there
more Daphnia than Bosmina in Osprey Lake, again showing the dominance of smaller species and
pointing to possibly greater food quality after early June. Compared to other lakes in the area during
August, Osprey Lake had near average total zooplankton density and diversity, high productivity, and
possibly high SSP.
35
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Table 7: Osprey Lake Zooplankton Summary Indices
Date
Total
Density
(#/ft3)
Shannon
Diversity
Gannon
Index
Cladoceran
Size index
D/b ratio
6/17/04
522.17
1.57
0.4
0.24
3.67
6/25/04
149.86
1.64
0.17
0.72
0.3
7/8/04
133.94
1.58
0.29
0.67
0.66
7/23/04
105.21
1.41
0.06
1.00
0.00
7/30/04
151.41
1.28
0.01
0.94
0.06
8/13/04
356.53
1.43
0.03
0.93
0.01
9/2/04
124.95
1.14
0.00
0.73
0.37
Average
MOM
1
0.14
0.75
0,72
4.6 Hydrologic Budget Calculations
The 2004 water year (October 1, 2003 through September 30, 2004) estimated hydrologic budget
for Osprey Lake is presented in Figures 15 and 16. Figure 15 presents the estimated inflow budget
and Figure 16 presents the estimated outflow budget. The inflow budget indicates that the inlet from
Little Round Lake is the major contributor of water to Osprey Lake. It accounts for over 68% of the
inflow. This large contribution of water from Little Round Lake indicates that the water quality of
Osprey Lake is influenced by the water quality of Big and Little Round Lakes which are upstream.
As the water quality of those lakes change, a corresponding change would also be noted in Osprey
Lake. Runoff from the watershed was the next largest with over 20%. The watershed runoff volume,
including overland flow and groundwater, represents. an annual water yield of approximately 12.2
inches from the Osprey Lake watershed. Direct precipitation on the lake surface, which is comprised
of both rain and snowfall, accounted for just over 7% and lake storage comprised the remainder at
3.9%.
Water leaving the lake via the outlet accounted for 81% of the outflow budget. Groundwater
seepage was the next largest output at over 13% and evaporation from the lake's surface comprised
the remainder at nearly 6%.
37
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4.7 Phosphorus Budget and Lake Water Quality Mass Balance
Model
The phosphorus budget modeling indicated that the total annual phosphorus loading to Osprey Lake
was 367 pounds, based on 2004 data. The results ofthe phosphorus loading budget are presented in
Figures 17 and 18. Figure 17 shows the phosphorus budget based on percentages ofthe total budget
and Figure 18 shows it based on pounds. The inflow water from Osprey Creels Contributed the
largest amour! ofphosphorus at 149 pounds (40%). The next largest source was the forested portion
of the watershed which contributed 103 lbs of phosphorus which is 28% ofthe total loading. The
wetlands were estimated to contribute 18 lbs (5%). By applying a wet and dry atmospheric deposition
rate of0.25 lbs/acre/yr to the surface of Osprey Lake, the atmospheric component ofthe phosphorus
loading is computed to be 52 lbs or 14%. Residential use and septic systems contribute 12 lbs (3%)
and 71bs (2%) ofthe annual load respectively. The pasturelgrassland contributed 11 pounds (3%).
The computations reveal that internal loading contributes 15 lbs (4%) of the total phosphorus load.
4.8 Culturaa Lutrophicatnoll Impacts on Osprey Lake
All ofthe land use practices within a lake's watershed impact the lake and determine its water quality.
These impacts result from the export of sediment and nutrients, primarily phosphorus, to a lake from
its watershed. Each land use contributes a different quantity of phosphorus to the lake, thereby
impacting the lake's water quality differently. Land uses resulting from human activity generally
accelerate the natural outrophication process of a lake. These land uses generally contribute larger
quantities ofphosphorus to alake than the natural land uses occurring prior to development. Cultural
eutrophication describes the acceleration of the natural eutrophication process caused by human
activities. The impacts of cultural eutrophication on Osprey Lake were evaluated in this study.
An assessment of the land uses within the Osprey Lake direct watershed indicated that there are two
types of land uses resulting from human activity. These land uses are:
1. PasturelGrassland- The total loading from pasture/grassland is estimated to
be 3.1% of the total phosphorus loading to Osprey Lake.
2. Residential - residential land use is comprised of the households within the
direct watershed and the septic systems located around the lake shore. The
total phosphorus loading to the direct watershed from residential land use is
estimated to be just over 5% of the total phosphorus loading.
The impacts of cultural eutrophication within the direct watershed on Osprey Lake were estimated
by modeling pre -development ill -lake phosphorus concentrations and comparing the estimated pre -
development phosphorus concentrations with current phosphorus concentrations (i.e. post -
development conditions). Four modeling scenarios were completed to assess the impacts of cultural
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eutrophication. The four scenarios consisted of the following:
1. Estimating the in -lake phosphorus concentration assuming forested land use (i.e. pre -
development condition) in place of pasture/grassland land use (i.e. current or post -
development condition).
2. Estimating the in -lake phosphorus concentration assuming forested land use (i.e. pre -
development condition) in place of residential land use (i.e. current or post -
development condition).
3. Estimating the in -lake phosphorus concentration assuming forested land use (i.e. pre -
development conditions) in place of pasture/grassland and residential land uses (i.e.
current or post -development conditions).
4. A large subdivision is being planned along the shoreline of the lake. The total
proposed development encompasses approximately 200 acres. The current land use
along this shoreline is forested. The current forested land use will be replaced by
residential land use and the resulting increase in the total phosphorus concentration
will be estimated.
The model indicates that the assumed conversion of forested land use to agricultural land use results
in a 0.2 ug/L (2%) increase in the total in -lake phosphorus concentration. This increase in
phosphorus does not result in a noticeable water quality change. The estimated 0.2 ug/L increase in
total phosphorus concentration does not result in a noticeable decrease in the average annual Secchi
disc transparency. This is based upon the regression relationship between total phosphorus and
Secchi disk depth as determined from the 2004 sampling data for Osprey Lake (Figure 19). The
predicted decrease in Secchi disk depth would be an overall reduction in water clarity of less than
l % based upon the 2004 average summer Secchi disk depth.
The model indicates that the assumed conversion of forested land use to residential land use results
in a 0.4 ug/L (4%) increase in the total in -lake phosphorus concentration. This increase in
phosphorus does not result in a noticeable water quality change. The estimated 0.4 ug/L increase in
total phosphorus concentrations results in an estimated decrease in the average annual Secchi disc
transparency of only two inches. This is based upon the regression relationship between total
phosphorus and Secchi disk depth as determined from the 2004 sampling data for Osprey Lake. "1 he
two inch decrease in Secchi disk depth correlates to 1 % decrease in the water clarity based upon the
2004 average summer Secchi disk depth of 14.9 feet.
The model indicates that the assumed conversion of forested land use to agricultural and residential
uses results in a 0.6 ug/L (6%) increase in the total in -lake phosphorus concentration. This increase
in phosphorus does not result in a noticeable water quality change. The estimated 0.6 ug/L increase
in total phosphorus concentration results in an estimated decrease in the average annual Secchi disc
transparency of 3.5 inches. This is based upon the regression relationship between total phosphorus
43
and Secchi disk depth as determined from the 2004 sampling data for Osprey Lake. This predicted
decrease in Secchi disk depth would be an overall reduction in water clarity of 2% from pre -
development levels based upon the 2004 average summer Secchi disk depth of 14.9 feet.
The model indicates that the proposed 200 acre development would result in a 2.85 ug/L (29%)
increase in the total in -lake phosphorus concentration. This increase in phosphorus does result in a
noticeable water quality change. The estimated 2.85 uglL increase in total phosphorus concentration
results in an estimated decrease in the average annual Secchi disc transparency of 1.4 feet or 16.5
inches. This is based upon the regression relationship between total phosphorus and Secchi disk depth
as determined fromthe 2004 sampling data for Osprey Lake. This predicted decrease in Secchi disk
depth would be an overall reduction in water clarity of 9% based upon the 2004 average summer
Secchi disk depth of 14.9 feet.
31
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5.0 Evaluation of Historical Water Quality Data
Long-term data going back to 1998 was available for Secchi Disk readings. Data was also available
dating back to 2000 for total phosphorus and chlorophyll -a. The historical data was collected at the
deep hole by LCO Conservation Department personnel.
An evaluation of the historic total phosphorus, chlorophyll -a and Secchi disk monitoring data
indicates that no statistically significant trends exist over the time frame for which data is available.
The differences in total phosphorus, chlorophyll -a and Secchi disk values can be attributed to natural
variation. See Figures 20 - 22 for charts of the yearly summer averages for total phosphorus,
chlorophyll -a and Secchi disk values respectively.
The summer TSI values (Figure 23) indicate that water clarity is typically better than what would be
expected based upon the total phosphorus and chlorophyll -a- readings. Even though the TSI values
were not the same for all of the parameters, they tended to follow the same general pattern, once
again suggesting that the lake is phosphorus limited.
In summary, an evaluation of the long-term monitoring data for Osprey Lake indicates that no
statistically significant trends exist based upon the available monitoring data. The variations from year
to year can be attributed to natural variation over this time period.
46
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6.0 Recommendations and Management Actions
The development of a comprehensive lake management plan for Osprey Lake is recommended in
order to maintain and possibly improve the existing status of the water quality. This plan should
include:
1. The development of a long-term water quality goal for the lake;
2. An evaluation of different watershed development scenarios to determine acceptable
(i.e., the water quality ofthe lake is within the established goal) and unacceptable (i.e.,
the water quality of the lake fails to meet its goal) development options;
3. Recommendations for watershed best management practices under future
development conditions;
4. Recommendations for ordinances to control watershed development;
5. Recommendations for riparian owner management practices;
6. Recommendations for best management plans to protect sensitive lands including
wetlands, steep slopes, undeveloped land, shoreline, etc.;
7. Algal study to determine species abundance and distribution;
8. A maerophyte study to determine the spatial coverage, density, and species
composition of the rnacrophyte community. A special area of concern would be
identification of Eurasian Water Milfoil.
9. Monitoring for Zebra mussels. Zebra mussel ❑ellegers were discovered in 2044 to be
present in Round Lake. The water from Round discharges into Osprey Lake which
would therefore place Osprey Lake into a high risk category for Zebra mussel
infestation.
51
References
Barr Engineering Company. 1998. Lac Courte Oreilles Management Plan.
Byron, S., C. Mechenich, and L. Klessig. 1997. Understanding Lake Data. University of
Wisconsin -Extension Publication # G3582.
Dillon, P.J. and F.H. Rigler; 1974. A test of a simple nutrient budget moc?cl predicting the
phosphorus concentration in lake water. J. Fisheries Research Board Canada 31:
1771-1778.
Gannon, J.E. and R.S. Stemberger. 1978. Zooplankton (especially crustaceans and rotifers)
as indicators of water quality. Transactions of the American Microscopic Society
97(1):16-35.
Linsley, R.K., Jr., M.A. Kohler, and J.L.H. Paulhus;1982. Hydrology for Engineering, Third
Edition. McGraw-Hill Book company. New York, New York.
Mills, E.L., D.M. Green, and A. Schiavone Jr. 1987. Use of zooplankton size to assess
community structure of fish populations in freshwater lakes. Journal of North
American Fisheries Management 7(3): 369-378.
Nurnberg, G.K., 1984. The prediction of internal phosphorus load in lakes with anoxic
hypolimnia. Limnol.Oceanogr. 29: 111-124
Osgood, R.A.;-
1989. Assessment of Lake Use - Impairment in the Twin Cities metropolitan
Area. Prepared for the Minnesota Pollution Control Agency. Metropolitan Council
Publication 590-89-130. 12 pp.
Panuska, J.C. and A.D. Wilson; 1994. Wisconsin Lake Model Spreadsheet User's Manual.
Wisconsin Department of Natural Resources. Lake Management Program. PUBL-
WR-363-94.
Panuska, J.C. and R.A. Lilly; 1995. Phosphorus Loadings from Wisconsin Watersheds:
Recommended Export Coefficients for Agricultural and Forested Watersheds.
WDNR Research Management Findings.
52
Appendix A
Osprey Lake 2004 Analytical Data
R.'
i
1
11^
Osprey Lake Year 2004 Analytical Data Results
Site: Middle -Deep 28'
Date
Tot Phos: Top
Chlorophyll -a
(ppb)
04/27/04
21
05/07/04
14
05/14/04
16
05/28/04
8
06/02/04
13
0.93
06/10/04
8
3.27
06/17/04
7
1.40
06/25/04
11
3.60
07/02/04
8
1.07
07/08/04
10
2.60
07/14/04
8
1.47
07/23/04
12
1.27
07/30/04
11
2.27
08/05/04
9
2.00
08/13/04
11
1.34
08/23/04
11
2.47
09/02/04
10
1.80
09/13/04
11
09/23/04
10
1.33
09/30/04
13
3.80
Appendix S
Osprey Lake Profiling Data
a
Osprey Lake 2004 Profiling Data
Site: Deep Middle 28'
Date
Depth
Temp
SpC
TDS
DO
pH
Secchi Disc
(feet)
(F)
(uS/cm)
(mg)L)
(mg/L)
(Feat)
04/27/04
top
45.1
77
50
11.25
8.50
13.5
3.3
45.06
77
50
11.27
8.52
6.6
45.04
77
50
11.28
8.50
9.9
45.02
77
50
11.28
8.49
13.2
44.96
77
50
11.27
8.49
16.5
44.93
77
50
11.27
8.51
19.8
44.86
77
50
11.26
8.48
23.1
44.61
77
50
11.18
8.45
26.5
44.2
76
50
11.13
8.47
05/07/04
top
50.86
78
50
12.09
9.20
12.5
3.3
50.85
78
50
12.14
8.97
6.6
50.81
78
50
12.17
8.91
9.9
50.79
78
50
12.20
8.86
13.2
50.8
78
50
12.22
8.86
16.5
50.75
78
50
12.23
8.81
19.8
50.75
78
50
12.24
8.79
23.1
50.65
77
50
12.26
8.79
26.5
50.5
77
50
12.29
8.79
I.
05/14/04
top
55.17
78
50
10.91
9.00
12.5
3.3
55.16
78
50
10.92
8.78
6.6
55.16
78
50
10.94
8.69
9.9
55.12
78
50
10.95
8.70
13.2
55.09
78
50
10.95
8.70
16.5
52.37
78
51
11.35
8.63
19.8
50.81
78
51
11.57
8.58
23.1
49.91
78
51
10.40
8.52
26.5
49.27
80
52
8.51
8.40
f
05/28/04
top
57.20
77
50
10.70
8.70
17.2
3.3
56.82
77
50
10.74
8.25
6.6
56.60
77
50
10.75
8.04
9.9
56.52
77
50
10.79
7.98
13.2
%38
77
50
10.77
7.96
16.5
55.92
78
50
10.62
7.87
i
19.8
54.22
78
51
9.83
7.79
23.1
52.27
79
52
8.58
7.67
26.5
51.05
81
53
5.50
7.49
06/02/04
top
59.10
77
50
10.90
8.13
12.2
3.3
59.09
77
50
10.85
7.99
6.6
59.03
77
50
10.90
7.93
9.9
58.99
77
50
10.92
7.97
13.2
58.93
77
50
10.89
7.98
16.5
58.86
77
50
10.91
7.94
19.8
55.20
78
51
9.72
7.82
�'
I�
■ 4
Date
Depth
Temp
SpC
TDS
DO
pH
(feet)
(F)
(US/cm)
(mg/L)
(mg/L)
23.1
53.26
80
52
6.94
7.59
26.5
50.75
88
57
4.85
7.29
06/10/04
top
66.86
78
51
9.34
8.49
3.3
66.80
78
51
9.39
8.32
6.6
66.76
78
51
9.39
8.27
9.9
66.63
78
51
9.42
8.20
13.2
61.35
78
51
10.03
8.15
16.5
59.15
78
50
9.84
8.02
19.8
56.90
78
51
9.31
7.93
23.1
55.26
79
51
6.68
7.75
26.5
53.23
82
53
3.50
7.53
06/17/04
top
70.32
79
51
9.30
8.77
3.3
70.09
78
51
9.32
8.53
6.6
69.87
78
51
9.35
8.36
9.9
66.95
78
51
9.48
8.29
13.2
64.25
77
50
9.46
8.18
16.5
60.50
77
50
9.44
8.08
19.8
57.19
78
51
7.80
7.91
23.1
54.76
81
52
3.89
7.69
26.5
53.24
84
55
1.13
7.59
06/25/04
top
64.96
79
51
8.65
8.29
3.3
64.97
79
51
8.66
8.18
6.6
64.92
79
51
8.72
8.15
9.9
64.89
79
51
8.74
8.15
13.2
64.89
79
51
8.77
8.13
16.5
63.47
79
52
8.61
8.09
19.8
58.15
79
51
8.05
8.07
23.1
55.45
82
53
2.53
7.74
26.5
53.90
85
55
0.85
7.49
07/02/04
top
71.86
80
52
7.60
8.21
3.3
70.83
80
52
7.83
8.01
6.6
70.25
80
52
7.95
8.07
9.9
69.21
80
52
8.07
8.04
13.2
65.84
79
52
8.31
8.12
16.5
64.65
80
52
8.02
7.95
19.8
61.20
79
52
7.28
7.82
23.1
56.89
81
53
2.98
7.35
26.5
55.43
83
55
0.95
7.24
07/08/04
top
68.47
80
52
n/a
8.34
3.3
68.39
80
52
n/a
8.38
6.6
68.10
80
52
n/a
8.38
9.9
68.02
80
52
n/a
8.38
13.2
67.99
80
52
n/a
8.36
16.5
63.84
80
52
n/a
8.24
19.8
60.81
79
51
n/a
7.86
23.1
56.66
82
53
n/a
7.59
26.5
55.10
85
56
n/a
7.45
Secchi Disc
(Feet)
15.5
16.8
12.5
14.2
14.2
Date
Depth
Temp
SpC
TDS
DO
pH
Secchi Disc
(feet)
(F)
(US/CM)
(mg/L)
(mg/L)
(Feet)
07/14/04
top
74.12
81
52
9.21
8.15
15.5
3.3
74.11
81
52
9.21
8.10
6.6
74.10
81
52
9.05
8.04
9.9
73.13
81
52
9.19
8.08
13.2
69.23
80
52
9.61
8.14
16.5
65.95
80
52
9.20
7.93
19.8
63.04
80
52
8.30
7.62
23.1
57.73
82
53
1.39
7.00
26.5
55.10
87
57
0.55
6.95
07/23/04
top
73.58
81
52
9.15
8.23
14.9
3.3
73.14
81
52
9.14
8.19
6.6
73.03
81
52
9.32
8.15
9.9
72.89
81
52
9.64
8.03
13.2
68.79
81
52
9.10
8.02
16.5
65.43
80
52
9.05
7.89
19.8
63.47
82
53
8.10
7.60
23.1
58.42
83
54
1.05
6.98
26.5
55.07
88
58
0.67
6.75
07/30/04
top
74.31
80
52
8.94
9.25
14.2
3.3
74.30
80
52
9.00
9.34
6.6
74.13
80
52
9.04
9.37
9.9
74.02
80
52
9.00
9.34
13.2
73.73
80
52
8.95
9.30
16.5
70.50
80
52
9.50
9.30
19.8
64.97
80
52
8.67
9.12
23.1
59.10
83
54
2.30
8.67
26.5
56.37
88
57
0.86
8.34
08/05/04
top
74.53
80
52
8.99
9.48
15.5
3.3
74.34
80
52
9.01
9.47
6.6
73.82
80
52
9.06
9.46
9.9
73.70
80
52
9.03
9.42
13.2
73.28
80
52
9.09
9.38
16.5
69.30
79
52
9.75
9.28
19.8
63.74
80
52
5.87
8.83
23.1
58.17
85
55
1.43
8.42
26.5
55.70
94
61
0.71
8.25
08/13/04
top
67.15
79
52
8.74
8.56
17.2
3.3
66.89
79
52
8.72
8.57
6.6
66.79
79
52
8.68
8.54
9.9
66.71
79
52
8.67
8.52
13.2
66.55
79
52
8.67
8.50
16.5
66.40
79
52
8.53
8.47
19.8
65.10
80
52
7.69
8.38
23.1
58.70
86
56
1.75
8.11
26.5
56.75
93
60
1.05
7.92
08/23/04
top
66.15
80
52
8.94
9.02
14.2
Date
Depth
Temp
SpC
TDS
DO
pH
(feet)
(F)
(US/cm)
(mg/L)
(mg/L)
3.3
66.16
80
52
8.95
9.00
6.6
66.15
80
52
8.93
9.00
9.9
66.14
80
52
8.95
8.99
13.2
66.13
80
52
8.95
8.97
16.5
66.10
80
52
8.96
8.96
19.8
65.96
80
52
8.89
8.93
23.1
64.32
80
52
7.59
8.83
26.5
56.55
146
95
0.95
8.09
09/02/04
top
67.78
80
52
10.60
8.81
3.3
67.78
80
52
10.61
8.79
6.6
67.70
80
52
10.67
8.78
9.9
67.56
80
52
10.55
8.76
13.2
66.82
80
52
10.57
8.77
16.5
66.45
80
52
10.34
8.70
19.8
65.75
80
52
9.16
8.47
23.1
64.08
83
54
4.44
8.06
26.5
58.65
101
66
0.58
7.87
09/13/04
top
68.39
80
52
9.69
8.82
3.3
68.10
80
52
9.80
8.76
6.6
67.81
80
52
9.72
8.73
9.9
67.73
80
52
9.65
8.70
13.2
67.61
80
52
9.65
8.67
16.5
67.27
80
52
9.53
8.62
19.8
66.66
80
52
8.87
8.55
23.1
63.87
84
55
1.26
8.15
26.5
59.29
106
69
0.42
8.02
09/23/04
top
67.21
80
52
7.18
9.16
3.3
67.00
80
52
7.17
9.15
6.6
66.87
80
52
7.22
9.14
9.9
66.33
80
52
7.19
9.12
13.2
66.20
80
52
7.05
9.08
16.5
66.07
80
52
7.00
9.02
19.8
65.99
80
52
6.83
8.97
23.1
65.79
80
52
6.60
8.89
26.5
64.37
82
54
2.05
8.58
09/30/04
top
63.38
80
52
8.81
8.59
3.3
63.37
80
52
8.74
8.55
6.6
63.37
80
52
8.62
8.51
9.9
63.37
80
52
8.58
8.49
13.2
63.37
80
52
8.55
8.47
16.5
63.36
80
52
8.53
8.45
19.8
63.34
80
52
8.48
8.41
23.1
63.22
80
52
8.29
8.38
26.5
62.40
80
52
8.28
8.39
Secchi Disc
(Feet)
15.2
17.2
14.5
11.6
Appendix C
Osprey Lake Level Data
Osprey Lake Water Year 2004 Staff Gauge Levels
Location: Lake Level in Bay by Boat Landing
Date Staff Level Comments
10/16/03
1.6 base level
10/22/03
1.58
10/29/03
1.57
04/01 /04
2.1
05/07/04
2.29 re -adjusted level to 1.68
05/14/04
1.72
05/28/04
1.8
06/02/04
1.92
06/10/04
1.97
06/17/04
1.98
06/25/04
1.94
07/02/04
1.84
07/08/04
1.92
07/14/04
1.87
07/23/04
1.83
07/30/04
2.06
08/05/04
1.98
08/13/04
2.09
08/23/04
2.14
08/27/04
2.15
09/02/04
2.21
09/13/04
2.29
09/23/04
2.36
09/30/04
2.35
I J
■
�I
Appendix D
Precipitation Data
Daily Precipitation Levels for Lac Courte Oreilles Reservation
October 1, 2003-September 30, 2004
Date
Precipitation
Leveb(inches)
10/11/03
.52
10/28/03
.40
10/30/03
.44
11/04/03
.10
11/17/03
.30
11/18/03
.03
11/23/03
.45
12/08/03
.20
12/09/03
.06
12/10/03
.19
12/14/03
.05
12/15/03
.10
12/16/03
.05
12/19/03
.02
12/22/03
.03
12/23/03
.01
12/27/03
.01
12/29/03
.10
12/30/03-01/06/04
.17
1/11/04
.05
1 /14/04
.11
1/23/04
.02
1 /27/04
.02
2/1/04
.15
kv-
2/2/04
.49
2/3/04
.12
2/6/04
.05
2/7/04
.03
2/8/04
02
2/9/04
.09
2/11/04
.05
2/20/04
.23
2/21 /04
.04
2/23/04
.08
2/24/04
.10
2/25/04-03/09/04
.48
03/10/04
.10
3/11/04
.15
3/13/04
.09
3/14/04
.06
3/16/04
.02
3/17/04
.04
3/25/04
.65
3/27/04
.02
3/28/04
.20
3/29/04
.08
4/7/04
.02
4/8/04
.11
4/18/04
3.30
4/19/04
1.00
4/20/04
.08
4/21/04
.15
4/25/04
.36
4/26/04
.10
4/27/04
.03
4/28/04
.02
5/7/04
.03
5/9/04
.10
5/10/04
.04
5/12/04
.30
5/13/04
.50
5/17/04
.45
5/20/04
.28
5/21/04
.04
5/22/04
.03
5/23/04
.73
5/27/04
.68
5/29/04
.02
5/30/04
.08
5/31 /04
1.09
6/1/04
.08
6/5/04
.63
6/8/04
.06
6/9/04
.20
6/11/04
.03
6/12/04
.45
6/13/04
.02
6/14/04
.02
6/16/04
.16
6/23/04
.15
I
6/24/04
.35
6/25/04
.01
6/28/04
.15
6/30/04
.24
7/4/04
.98
7/6/04
.04
7/9/04
.01
7/10/04
.15
7/12/04
.35
7/13/04
.05
7/19/04
.24
7/20/04
.07
7/28/04
.45
7/29/04
1.75
7/30/04
.33
8/7/04
.11
8/8/04
.49
8/9/04
.45
8/10/04
.20
8/11/04
.41
8/16/04
.84
8/18/04
.01
8/22/04
.02
8/25/04
.02
8/26/04
.13
8/30/04
.06
8 /31 /04
.08
9/5/04
1.64
9/6/04
.32
9/14/04
.05
9/15/04
1.00
9/21/04
.03
9/23/04
.35
9/27/04
.05
Totals For Year
29.54 inches
Appendix E
Inflow and Outflow Staff Gauge Data
■ - 7 m -
Osprey Lake Water Year 2004 Staff Gauge Levels
Location: Inlet -Little Round Lake Dam
Date Staff Level Comments
10/16/03
4.80
10/22/03
4.76
10/29/03
4.74
11/17/03
4.70
04/19/04
5.55
04/27/04
5.55
05/07/04
5.46
05/14/04
5.54
05/28/04
5.60
06/02/0
U. r 1_
06/10/04
5.74
06/17/04
5.70
06/21 /04
5.62
06/25/04
5.56
07/02/04
5.50
07/08/04
5.53
07/09/04
5.50
07/15/04
5.48
07/23/04
5.36
07/29/04
5.48
07/30/04
5.46
08/04/04
5.44
08/05/04
5.40
08/13/04
5.40
08/16/04
5.42
08/20/04
5.36
08/23/04
5.30
09/02/04
5.26
09/08/04
5.35
09/16/04
5.40
09/17/04
5.38
10/4/04
5.24
Osprey Lake Water Year 2004 Staff Gauge Levels
Location: Outlet "NN Culvert" -Osprey Creek
Date Staff Level Comments
10/16/03
1.77 base level
10/22/03
1.77
10/29/03
1.78
11 /17/03
1.78
04/27/04
2.59
05/07/04
2.48
05/11 /04
2.49
05/14/04
2.53
05/28/04
2.65
06/02/04
2.77
06/10/04
2.77
06/17/04
2.82
06/21/04
2.8
06/25/04
2.78
07/02/04
2.73
07/08/04
2.75
07/09/04
2.75
07/15/04
2.73
07/23/04
2.53
07/29/04
2.76
07/30/04
2.7
08/04/04
2.6
08/05/04
2.64
08/13/04
2.68
08/16/04
2.71
08/20/04
2.55
08/23/04
2.59
09/02/04
2.49
09/08/04
2.55
09/16/04
2.52
9117/04
2.45
10/4/04
2.29
Appendix F
Inlet/Outlet Flow and Total Phosphorus
Data Summary
Osprey Lake Inflow - Water Year 2004
Location: Inlet -Little Round Lake Dam
05/07/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
I f s
ft"2
c( fsl -Gau e ft
0.0
1.0
1.3
0.515
1.30
0.670 5.46
1.0
1.0
1.3
0.552
1.30
0.718
2.0
1.0
1.3
0.629
1.30
0.818
3.0
1.0
1.3
0.742
1.30
0.965
4.0
1.0
1.3
0.691
1.30
0.898
5,0
1.0
1.3
0.569
1.30
0.740
6.0
1.0
1.4
0.593
1.40
0.830
7
1.0
1.3
0.742
1.30
0.965
8
1.0
1.3
0.705
1.30
0.917
9
1.0
1.3
0.663
1.30
0.862
10
1.0
1.3
0.605
1.30
0.787
11
1.0
1.3
0.443
1.30
0.576
9.74
05/14/04 Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
(it
(fry
(fps)
ft"2j
cfs Gauge ft
0.0
_
1.0
1.3
0.527
1.30
0.685 5.54
1.0
1.0
1.3
0.725
1.30
0.943
2.0
1.0
1.3
0.742
1.30
0.965
3.0
1.0
1.3
0.694
1.30
0.902
4.0
1.0
1.3
0.673
1.30
0.875
5.0
1.0
1.4
0.588
1.40
0.823
6.0
1.0
1.3
0.643
1.30
0.836
7
1.0
1.3
0.752
1.30
0.978
8
1.0
1.3
0.695
1.30
0.904
9
1.0
1.3
0.622
1.30
0.809
10
1.0
1.3
0.575
1.30
0.748
11
1.0
1.3
0.505
1.30
0.657
10.12
05/28/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
(ft)
(ft)
(f_p�s
(ft"2)
cfs Gau e ft
_Point
0
1.0
1.4
0.568
1.40
0.795 5.60
1
1.0
1.5
0.654
1.50
0.981
2
1.0
1.5
0.758
1.50
1.137
3
1.0
1.5
0.720
1.50
1.080
4
1.0
1.4
0.699
1.40
0.979 ±�
5
1.0
1.5
0.578
1.50
0.867
6
1.0
1.4
0.594
1.40
0.832
7
1.0
1.4
0.698
1.40
0.977
8
1.0
1.4
0.746
1.40
1.044
9
1.0
1.4
0.687
1.40
0,962
10
1.0
1.4
0.598
1.40
0.837
11
1.0
1.4
0.602
1.40
0.843
4;
11.33
06/10/04 *Storm Event (2.5" rain during the week)
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
(ft
ft
f
ft-2)
cis Gauge ft
0
1
1.5
0.525
1.50
0.788 5.74
1
1
1.6
0.706
1.60
1.130
2
1
1.6
0.778
1.60
1.245
3
1
1.6
0.688
1.60
1.101
4
1
1.5
0.710
1.50
1.065
5
1
1.6
0,546
1.60
0.874
6
1
1.5
0.587
1.50
0.881
7
1
1.5
0.627
1.50
0.941
8
1
1.5
0.789
1.50
1.184
9
1
1.5
0.625
1.50
0.938
10
1
1.5
0.610
1.50
0.915
11
1
1.5
0.506
1.50
0.759
11.82
06/17/04 *Storm Event (3.5" rain on 718/02)
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
ft
ft
(fps)
ft"2
(cis) Gauge (ft)
0
1
1.5
0.652
1.50
0,978 5.70
1
1
1.6
0.819
1.60
1.310
2
1
1.6
0.932
1.60
1.491
3
1
1.6
1.080
1.60
1.728
4
1
1.5
1.140
1.50
1.710
5
1
1.5
0.941
1.50
1.412
6
1
1.5
1.020
1.50
1.530
7
1
1.5
0.981
1.50
1.472
8
1
1.5
0.974
1.50
1.461
9
1
1.5
1.100
1.50
1.650
10
1
1.5
1.020
1.50
1.530
11
1
1.5
0.848
1.50
1.272
17.54
06/25/04
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
(ft)
(ft)
(fps)
(ft-2)
cfs Gauge ft
0
1
1.3
0.565
1.30
0.735 5.56
1
1
1.3
0.698
1.30
0.907
2
1
1.3
0.824
1.30
1.071
3
1
1.3
0.724
1.30
0.941
4
1
1.3
0.602
1.30
0.783
5
1
1.4
0.5,4;
1.40
0.706
6
1
1.3
0.789
1.30
1.026
7
1
1.3
0.827
1.30
1.075
8
1
1.3
0.654
1.30
0.850
9
1
1.3
0.624
1.30
0.811
10
1
1.3
0.505
1.30
0.657
11
1
1.3
0.575
1.30
0.748
10.31
07/02/04
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
ft
ft
f
ft" 2
cfs Gauge f�
0
1
1.4
0.748
1.40
1.047 5.50
1
1
1.4
0.956
1.40
1.338
2
1
1.3
0.760
1.30
0.988
3
1
1.3
0.772
1.30
1.004
4
1
1.3
0.778
1.30
1.011
5
1
1.3
0.778
1.30
1.011
6
1
1.3
0.715
1.30
0.930
7
1
1.3
0.779
1.30
1.013
8
1
1.3
0.815
1.30
1.060
9
1
1.3
0.819
1.30
1.065
10
1
1.3
0.819
1.30
1.065
11
1
1.3
0.705
1.30
0.917
12.45
07/08/04 "Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
U
(:qL
(!Ps)
ft"2)
(cfs Gauge ft
0
1
1.3
0.792
1.30
1.030 5.53
1
1
1.4
0.850
1.40
1.190
2
1
1.4
1.000
1.40
1.400
3
1
1.4
0.936
1.40
1.310
4
1
1.4
0.943
1.40
1.320
5
1
1.4
0.855
1.40
1.197
6
1
1.3
0.866
1.30
1.126
7
1
1.3
0.930
1.30
1.209
8
1
1.3
0.882
1.30
1.147
9
1
1.3
0.872
1.30
1.134
10
1
1.3
0.880
1.30
1.144
11
1
1.3
0.598
1.30
0.777
13.98
07/15/04 *Baseflow
Dist Initial
Point
Width
_ fi ty
depth Velocity Area
f� i)� �$ 2�
Discharge Staff
ic€s) Gauge fi]
_
0
1
1.3
0.599
1.30
0.779 5.14x-
1
1
1.4
0.784
1.40
1.098
2
1
1.4
0.828
1.40
1.159
3
1
1.3
0.862
1.30
1.121
4
1
1.3
0.928
1.30
1.206
5
1
1.3
0.878
1.30
1.141
6
1
1.3
0.866
1.30
1.126
7
1
1.3
0.807
1.30
1.049
8
1
1.3
0.800
1.30
1.040
9
1
1.3
0.815
1.30
1.060
10
1
1.3
0.862
1.30
1.121
11
1
1.3
0.588
1.30
0.764
12.66
07/30/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
ift)
-���t
s
ft"
cfs Gauge f't
0
1
1.3
0.554
1.30
0.720 5.46
1
1
1.3
0.505
1.30
0.657
2
1
1.3
0.655
1.30
0.852
3
1
1.3
0.593
1.30
0.771
4
1
1.3
0.575
1.30
0.748
5
1
1.3
0.550
1.30
0..715
6
1
1.3
0.485
1.30
0.631
7
1
1.3
0.612
1.30
0.796
8
1
1.3
0.587
1.30
0.763
9
1
1.3
0.553
1.30
0.719
10
1
1.3
0.561
1.30
0.729
11
1
1.3
0.492
1.30
0.640
8.74
08/05/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
(ft)
(ft)---(fps)
(ft"2
cfs Gauge- ft
0
1
1.3
0.455
1.30
0.592 5.40
1
1
1.3
0.586
1.30
0.762
2
1
1.3
0.618
1.30
0.803
3
1
1.3
0.557
1.30
0.724
4
1
1.3
0.623
1.30
0.810
5
1
1.3
0.549
1.30
0.714
6
1
1.2
0.489
1.20
0.587
7
1
1.2
0.596
1.20
0.715
8
1
1.2
0.615
1.20
0.738
9
1
1.2
0.545
1.20
0.654
10
1
1.2
0.505
1.20
0.606
11
1
1.2
0.487
1.20
0.584
8.29
08/16/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
(ft)
(ft)
�fpsy
fs k^2
cfs Gauge #i i
0
1
1.3
0.451
1.30
0.586 5.42
1
1
1.3
0.599
1.30
0.779
2
1
1.3
0.617
1.30
0.802 I;
3
1
1.3
0.618
1.30
0.803 i
4
1
1.3
0.632
1.30
0.822
5
1
1.3
0.587
1.30
0.763
6
1
1.3
0.436
1.30
0.567
7
1
1.2
0.502
1.20
0.602
8
1
1.2
0.601
1.20
0.721
9
1
1.2
0.586
1.20
0.703
10
1
1.2
0.507
1.20
0.608
11
1
1.2
0.466
1.20
0.559
.^- 8.32
- fG
I
08/23/04
*Baseflow
J
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
j)
ft
s
ft"2
cfs Gauge ft i
J 0
1
1.2
0.340
1.20
0.408 6.30
1
1
1.2
0.432
1.20
0.518
2
1
1.2
0.446
1.20
0.535
3
1
1.2
0.449
1.20
0.539
4
1
1.2
0.449
1.20
0.539
5
1
1.1
0.421
1.10
0.463
6
1
1.2
0.395
1.20
0.474
7
1
1.2
0.428
1.20
0.514
8
1
1.2
0.438
1.20
0.526
9
1
1.2
0.445
1.20
0.534
10
1
1.2
0.376
1.20
0.451
11
1
1.1
0.340
1.10
0.374
-_ i
5.87
09102/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
ti.
ft
f s
ft"2
cfs Gauge ft
0
1
1.1
0.205
1.10
0.226 5.26
1
1
1.1
0.278
1.10
0.306
2
1
1.1
0.287
1.10
0.316
3
1
1.1
0.245
1.10
0.270
4
1
1.1
0.315
1.10
0.347
5
1
1.1
0.247
1.10
0.272
6
1
1.1
0.216
1.10
0.238
7
1
1.1
0.294
1.10
0.323
8
1
1.1
0.305
1.10
0.336
9
1
1.1
0.244
1.10
0.268
10
1
1.1
0.276
1.10
0.304
11
1
1.1
0.195
1.10
0.215
3.42
09/16/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
ft
ft(fps)ftr,
cfs Gauge
0
1
1.3
0.356
1.30
0.463 5.40
1
1
1.3
0.307
1.30
0.399
2
1
1.3
0.415
1.30
0.540
3
1
1.3
0.430
1.30
0.559
4
1
1.3
0.293
1.30
0.381
5
1
1.3
0.298
1.30
0.387
6
1
1.2
0.275
1.20
0.330
7
1
1.2
0.205
1.20
0.246
8
1
1.2
0.185
1.20
0.222
9
1
1.2
0.210
1.20
0.252
10
1
1.2
0.197
1.20
0.236
11
1
1.2
0.223
1.20
0.268
4.28
Osprey Lake Outflow - Water Year 2004
Location: "NN" Culverts -'Osprey Creek
05/07/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
it
ft
(fps)
ft"2
cfs Gauge (ft
0
1.0
0.8
0.364
0.80
0.291 2.48
1
1.0
0,9
2.19
0.90
1.971
2
1.0
1.0
2.770
1.00
2.770
3
1.0
0.9
1.720
0.90
1.548
4
1.0
0.7
0.377
0.70
0.264
5
1.0
0.8
0.225
0.80
0.180
6
1.0
1
1.500
1.00
1.500
7
1.0
1.1
2.590
1.10
2.849
8
1.0
1.1
2.590
1.10
2.849
9
1.0
0.9
0.454
0.90
0.409
14.63
05/14/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge
Staff
Point
ft
ft
f s
ft"2
cis)Gau
a ft
0
1.0
0.9
0.413
0.90
0.372
2.53
1
1.0
0.9
1.14
0.90
1.026
2
1.0
1.0
2.710
1.00
2.710
3
1.0
1.0
2.320
1.00
2.320
4
1.0
0.9
1.870
0.90
1.683
5
1.0
0.8
0.320
0.80
0.256
6
1.0
1
0.654
1.00
0.654
7
1.0
1.1
2.160
1.10
2.376
8
1.0
1.1
2.740
1.10
3.014
9
1.0
1
0.305
1.00
0.305
14.72
05/28/04
*Baseflow
�f
Dist Initial
Wdth
depth
Velocity
Area
Discharge
Sta;fi
Point
ft
ft
f s
ft^2
cfs
Gauge ft
0
1.0
1.0
0.297
1.00
0.297
2.65
1
1.0
1.0
1.18
1.00
1.180
2
1.0
1.1
2.520
1.10
2.772
a
3
1.0
1.1
2.130
1.10
2.343
4
1.0
1.0
0.605
1.00
0.605
5
1.0
1
0.358
1.00
0.358
6
1.0
1.1
0.553
1.10
0.608
7
1.0
1.2
1.890
1.20
2.268
8
1.0
1.2
2.630
1.20
3.156
9
1.0
1.1
0.344
1.10
0.378
-
13.97
ill
06/10104 *Storm Event (2.5" rain during the week)
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
ft]
Lfrt)
ffps)
(f02j
cfs Gauge ft
_
0
1.0
-
1.0
0.323
1.00
0.323 2.77
1
1.0
1.0
1.24
1.00
1.240
2
1.0
1.1
2.650
1.10
2.915
3
1.0
1.1
1.980
1.10
2.178
4
1.0
1.0
0.569
1.00
0.569
5
1.0
1
0.475
1.00
0.475
6
1.0
1.1
0.710
1.10
0.781
7
1.0
1.2
2.060
1.20
2.472
8
1.0
1.2
2.760
1.20
3.312
9
1.0
1.1
0.275
1.10
0.303
14.57
06/17/04 *Storm Event (3.5" rain on 718/02)
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
qt}
)
(Jp __(ft"2)
(cfs) Gauge f�
0
1.0
1.0
0.280
1.00
0,280 2.82
1
1.0
1.1
0.722
1.10
0.794
2
1.0
1.2
2.380
1.20
2.856
3
1.0
1.2
2.930
1.20
3.516
4
1.0
1.2
1.510
1.20
1.812
5
1.0
1.1
0.426
1.10
0.469
6
1.0
1.2
1.040
1.20
1.248
7
1.0
1.3
2.420
1.30
3.146
8
1.0
1.3
2.950
1.30
3.835
9
1.0
1.2
0.181
1.20
0.217
18.17
06/26/04
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
(ft)��)
OP 5
ftw2
cfs Gauge eft)
0
1.0
1.0
0.215
1.00
0.215 2.78
1
1.0
1.1
0.824
1.10
0.906
2
1.0
1.1
2.560
1.10
2.816
3
1.0
1.2
2.750
1.20
3.300
4
1.0
1.2
1.250
1.20
1.500
5
1.0
1.1
0.345
1.10
0.380
6
1.0
1.2
1.210
1.20
1.452
7
1.0
1.3
2.540
1.30
3.302
8
1.0
1.3
2.760
1.30
3.588
9
1.0
1.1
0.188
1.10
0.207
17.67
07/02/04
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
€f
__-Af
S)
2)
(cft) Gauge (ft)
0
1.0
1.0
0.341
1.00
0.341 2.73
1
1.0
1.1
0.359
1.10
0.395
2
1.0
1.2
1.750
1.20
2.100
3
1.0
1.2
1.970
1.20
2.364
4
1.0
1.2
1.720
1.20
2.064
5
1.0
1
0.225
1.00
0.225
6
1.0
1.1
0.378
1.10
0.416
7
1.0
1.3
1.940
1.30
2.522
8
1.0
1.3
1.840
1.30
2.392
9
1.0
1.1
0.215
1.10
0.237
13.06
07/08/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area Discharge Staff
Point(ft)_
Ft
(f",
i1�- 2) -
(cfs} Gauge (ft)
0
1.0
1.0
0.352
1.00
0.352 2.75
1
1.0
1.1
0.79
1.10
0.869
2
1.0
1.2
2.190
1.20
2.628
3
1.0
1.2
2.310
1.20
2.772
4
1.0
1.1
1.380
1.10
1.518
5
1.0
1
0.425
1.00
0.425
6
1.0
1.2
0.708
1.20
0.850
7
1.0
1.2
2.100
1.20
2.520
8
1.0
1.3
2.460
1.30
3.198
9
1.0
1.3
1.520
1.30
1.976
17.11
07/15/04 *Baseflow
Dist Initial Width
depth
Velocity
Area
Discharge Staff
Point
(ft)
ft
(fps)
ft^2
(Cfs) Gauge (ft)
0
1.0
1.0
0.351
1.00
0.351 2.73
1
1.0
1.1
0.751
1.10
0.826
2
1.0
1.2
2.020
1.20
2.424
3
1.0
1.2
1.730
1.20
2.076
4
1.0
1.2
1.080
1.20
1.296
5
1.0
1
0.182
1.00
0.182
6
1.0
1.2
1.120
1.20
1.344
7
1.0
1.3
2.020
1.30
2.626
8
1.0
1.4
1.900
1.40
2.660
9
1.0
1.3
0.343
1.30
0.446
14.23
07/30/04 *Baseflow
Dist Initial Width
depth
Velocity
Area
Discharge Staff
Point
(ft)
((fps)__
ft"2 � Pau a ft
0
1.0
1.1
0.315
1.10
0.347 2.70
1
1.0
1.2
1.39
1.20
1.668
2
1.0
1.2
1.650
1.20
1.980
3
1.0
1.2
1.190
1.20
1.428
4
1.0
1.1
0.205
1.10
0.226
5
1.0
1.1
0.258
1.10
0.284
6
1.0
1.3
1.410
1.30
1.833
7
1.0
1.3
1.820
1.30
2.366
8
1.0
1.3
1.130
1.30
1.469
9
1.0
1.2
0.273
1.20
0.328
11.93
08/05/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
eft
tfps
[ft"2)
_ (cfs) Gau a (ft)
0
1.0
1.0
0.269
1.00
0.269 2.64
1
1.0
1.2
0.715
1.20
0.858
2
1.0
1.2
1.070
1.20
1.284
3
1.0
1.2
1.000
1.20
1.200
4
1.0
1.1
0.395
1.10
0.435
5
1.0
1
0.285
1.00
0.285
6
1.0
1.2
0.565
1.20
0.678
7
1.0
1.2
1.440
1.20
1.728
8
1.0
1.3
1.100
1.30
1.430
9
1.0
1.1
0.402
1.10
0.442
8.61
08116/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
(ft��ft)
f s
ft"2
��_ Gauge �ft�
0
1.0
1.1
0.210
1.10
0.231 2.71
1
1.0
1.2
0.457
1.20
0.548
2
1.0
1.2
0.965
1.20
1.158
3
1.0
1.2
1.070
1.20
1.284
4
1.0
1.2
0.323
1.20
0.388
5
1.0
1.2
1.245
1.20
1.494
6
1.0
1.3
0.680
1.30
0.884
7
1.0
1.3
1.080
1.30
1.404
8
1.0
1.3
1.230
1.30
1.599
9
1.0
1.2
0.302
1.20
0.362
9.35
08/23/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
_ Point
�� -
-�--
(fps
^2�
__(_�fs) Gauge (ft)
0
1.0
1.0
0.210
1.00
0.210 2.59
1
1.0
1.1
0.286
1.10
0.315
2
1.0
1.2
0.642
1.20
0.770
3
1.0
1.2
0.729
1.20
0.875
4
1.0
1.1
0.318
1.10
0.350
5
1.0
1.1
0.000
1.10
0.000
6
1.0
1.2
0.556
1.20
0.667
7
1.0
1.2
0.891
1.20
1.069
8
1.0
1.2
0.525
1.20
0.630
9
1.0
1.1
0.000
1.10
0.000
4.89
09/02/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
ftL---C4)
(fps)
ft"2
cfs Gauge (ft)
0
1.0
0.9
0.000
0.90
0.000 2.49
1
1.0
0.9
0
0.90
0.000
2
1.0
1.0
0.187
1.00
0.187
3
1.0
1.1
0.352
1.10
0.387
4
1.0
1.0
0.297
1.00
0.297
5
1.0
0.9
0.000
0.90
0.000
6
1.0
1
0.155
1.00
0.155
7
1.0
1.1
0.307
1.10
0.338
8
1.0
1.1
0.417
1.10
0.459
9
1.0
1.1
0.000
1.10
0.000
1.82
09/16/04 *Baseflow
Dist Initial
Width
depth
Velocity
Area
Discharge Staff
Point
(ft)
ft
f s
ft^2)
Pau e ft
0
1.0
1.0
0.105
1.00
_(cfs)
0.105 2.52
1
1.0
1.1
0.183
1.10
0.201
2
1.0
1.1
0.469
1.10
0.516
3
1.0
1.1
0.522
1.10
0.574
4
1.0
1.0
0.000
1.00
0.000
5
1.0
0.9
0.000
0.90
0.000
6
1.0
1.1
0.289
1.10
0.318
7
1.0
1.1
0.642
1.10
0.71
8
1.0
1.1
0.581
1.10
0.639
9
1.0
1.1
0.000
1.10
0.000
3.06
Osprey Lake Year 2004 Analytical Data Results
Site: Inlet -Little Round Lake Dam
Date
Tot. Phos: Top Chlorophyll -a
Comments
(ppb) (ppb)
05/07/04
15
05/14/04
9
storm event
05/28/04
7
06/10/04
11
06/17/04
12
06/25/04
14
07/02/04
11
07/08/04
326
storm event
07/15/04
9
07/23/04
11
07/29/04
12
storm event
07/30/04
11
08/05/04
10
08/16/04
10
storm event
08/23/04
10
09/02/04
13
09/16/04
9
storm event
Osprey Lake Year 2004 Analytical Data Results
Site: Outlet -Osprey Creek-"NN Culvert"
Date
Tot. Phos: Top Chlorophyl"
Comments
(PPb) (ppb)
05/07/04
13
05/14/04
14
Storm event
05/28/04
11
06/10/04
12
06/17/04
13
06/25/04
11
07/02/04
11
07/08/04
10
Storm event
07/15/04
11
07/23/04
13
07/29/04
14
Storm event
07/30/04
12
08/05/04
10
08/16/04
9
Storm event
08/23/04
8
09/02/04
9
09/16/04
11
Storm event