Vitals Physical Characteristics MN Lake ID: 56-0142-00 Surface area (acres): 2,080 Zoning Authority: The City of Perham Littoral area (acres): 764 Lake Classification: Drainage Lake % Littoral area: 37% Major Drainage Basin: Red River Max depth (ft): 72 Latitude/Longitude: 46.62916667/-95.54055556 Mean depth (ft): 24 Water Body Type: Public Inlets/Outlets/Accesses: 1/1/2 Invasive Species: None Lakeshed to lake area ratio: 2:1 Total Phosphorus Little Pine Lake is phosphorus limited, which means that algae and aquatic plant growth is dependent upon available phosphorus. Total phosphorus was evaluated in Little Pine Lake from 1996-1998 and 2001-2011. Most of the total phosphorus results fall within the eutrophic range, though some are within the mesotrophic range. The higher phosphorus in spring and fall could be due to lake turnover Total phosphorus has no trend. Chlorophyll a Chlorophyll a is the pigment that makes plants and algae green. It is tested in lakes to determine the algae concentration or how green the water is. Chlorophyll a concentrations greater than 10 ug/L are perceived as a mild algae bloom, while concentrations greater than 20 ug/L are perceived as a nuisance. Chlorophyll a was evaluated in Little Pine Lake in 1980, 1985, 1986, 1996-1998, and 2001- 2011. Early in the year (May and June) the concentrations hover around the 10 mg/L (Figure 8). Some years experienced nuisance algae blooms in midsummer (July and August). In 1996 there were numerous readings above the 20 mg/L. Chlorophyll a concentrations had no trend. Transparency (Secchi Depth) Transparency is how easily light can pass through a substance. In lakes it is how deep sunlight penetrates through the water. Plants and algae need sunlight to grow, therefore they are only found in areas of lakes where the sun penetrates. Water transparency depends on the amount of particles in the water. An increase in particulates results in a decrease in transparency. The annual mean transparency for Little Pine Lake ranges from 4.7 to 9.8 feet, and appears relatively uniform throughout the lake. Transparency on the lake has no trend. Trophic State Index (TSI) Phosphorus (nutrients), chlorophyll a (algae concentration), and Secchi depth (transparency) are interrelated. As phosphorus increases, there is more food available for algae, resulting in increased algal concentrations. When algal concentrations increase, the water becomes less transparent and the Secchi depth decreases. The results from these three measurements cover different units and ranges and thus cannot be directly compared or averaged. In order to standardize these measurements to make them directly comparable, we convert them to a tropic state index (TSI). The mean TSI for Little Pine Lake is 53; falling in the eutrophic category (TSI 50-70). These lakes have characteristic green water most of the summer. "Eu" means true and the root "trophy" means nutrients therefore, eutrophic literally means true nutrients or truly nutrient rich (phosphorus). Eutrophic lakes are usually shallow, and are found where the soils are fertile, and usually have abundant aquatic plants and algae. East Otter Tail County Water Quality Factsheet Little Pine Lake DNR ID: 56-0142-00 Little Pine Lake total phosphorus, chlorophyll a, and transparency historical ranges. The arrow represents the range and the black dot represents the historical mean (Primary Site 206). Figure adapted after Moore and Thornton, [Ed.]. 1988. Lake and Reservoir Restoration Guidance Manual. (Doc. No. EPA 440/5-88-002) Hypereutrophic Eutrophic Mesotrophic Oligotrophic 100 0 50 40 70 Little Pine Lake Local association information: Big and Little Pine Improvement District
Transcript
Vitals Physical Characteristics
MN Lake ID: 56-0142-00 Surface area (acres): 2,080
Zoning Authority: The City of Perham Littoral area (acres): 764
Lake Classification: Drainage Lake % Littoral area: 37%
Major Drainage Basin: Red River Max depth (ft): 72
Latitude/Longitude: 46.62916667/-95.54055556 Mean depth (ft): 24
Water Body Type: Public Inlets/Outlets/Accesses: 1/1/2
Invasive Species: None Lakeshed to lake area ratio: 2:1
Total Phosphorus Little Pine Lake is phosphorus limited, which means that algae and aquatic plant growth is dependent upon available phosphorus. Total phosphorus was evaluated in Little Pine Lake from 1996-1998 and 2001-2011. Most of the total phosphorus results fall within the eutrophic range, though some are within the mesotrophic range. The higher phosphorus in spring and fall could be due to lake turnover Total phosphorus has no trend.
Chlorophyll a Chlorophyll a is the pigment that makes plants and algae green. It is tested in lakes to determine the algae concentration or how green the water is. Chlorophyll a concentrations greater than 10 ug/L are perceived as a mild algae bloom, while concentrations greater than 20 ug/L are perceived as a nuisance. Chlorophyll a was evaluated in Little Pine Lake in 1980, 1985, 1986, 1996-1998, and 2001-2011. Early in the year (May and June) the concentrations hover around the 10 mg/L (Figure 8). Some years experienced nuisance algae blooms in midsummer (July and August). In 1996 there were numerous readings above the 20 mg/L. Chlorophyll a concentrations had no trend. Transparency (Secchi Depth) Transparency is how easily light can pass through a substance. In lakes it is how deep sunlight penetrates through the water. Plants and algae need sunlight to grow, therefore they are only found in areas of lakes where the sun penetrates. Water transparency depends on the amount of particles in the water. An increase in particulates results in a decrease in transparency. The annual mean transparency for Little Pine Lake ranges from 4.7 to 9.8 feet, and appears relatively uniform throughout the lake. Transparency on the lake has no trend.
Trophic State Index (TSI) Phosphorus (nutrients), chlorophyll a (algae concentration), and Secchi depth (transparency) are interrelated. As phosphorus increases, there is more food available for algae, resulting in increased algal concentrations. When algal concentrations increase, the water becomes less transparent and the Secchi depth decreases. The results from these three measurements cover different units and ranges and thus cannot be directly compared or averaged. In order to standardize these measurements to make them directly comparable, we convert them to a tropic state index (TSI). The mean TSI for Little Pine Lake is 53; falling in the eutrophic category (TSI 50-70). These lakes have characteristic green water most of the summer. "Eu" means true and the root "trophy" means nutrients therefore, eutrophic literally means true nutrients or truly nutrient rich (phosphorus). Eutrophic lakes are usually shallow, and are found where the soils are fertile, and usually have abundant aquatic plants and algae.
East Otter Tail County Water Quality Factsheet
Series
Little Pine Lake DNR ID: 56-0142-00
Little Pine Lake total phosphorus, chlorophyll a, and transparency historical
ranges. The arrow represents the range and the black dot represents the
historical mean (Primary Site 206). Figure adapted after Moore and Thornton,
[Ed.]. 1988. Lake and Reservoir Restoration Guidance Manual. (Doc. No. EPA
440/5-88-002)
Hypereutrophic
Eutrophic
Mesotrophic
Oligotrophic
100
0
50
40
70
Little Pine Lake
Local association information: Big and Little Pine Improvement District
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Little Pine Lake 56-0142-00 OTTERTAIL COUNTY
Lake Water Quality
Summary
Little Pine Lake is located on the northeast side of Perham, MN in Otter Tail County. It covers 2,080 acres and is circular in shape. Little Pine Lake has two inlets and one outlet, classifying it as a drainage lake. The Otter Tail River enters in two locations: 1) under County Highway 51 from the outlet of Mud Lake, and 2) from a culvert under County Highway 51, north of Mud Lake. The outlet is located along the east shore. The Otter Tail River then flows into Big Pine Lake, just to the west.
Water quality data have been collected on Little Pine Lake in 1958, 1980, and 1985-2011 (Table 3). These data show that the lake is eutrophic, which is characteristic of a shallow lake with abundant aquatic plants, algae, and bass (see page 9). Big and Little Pine Lakes Improvement District was formed in 1999. Their vision and purpose is “committed to the protection and enhancement of the quality of their water, its surroundings, and its fisheries for now and future generations.” The LID adopted a sustainable lakes management plan in 2004. They are also a member of the Otter Tail County Coalition of Lake Associations (COLA). Table 1. Little Pine Lake location and key physical characteristics.
Location Data
MN Lake ID: 56-0142-00
County: Otter Tail
Ecoregion: Northern Central Hardwood Forests
Major Drainage Basin: Red River
Latitude/Longitude: 46.62916667 / -95.54055556
Invasive Species: None
Physical Characteristics
Surface area (acres): 2,080
Littoral area (acres): 764
% Littoral area: 37%
Max depth (ft), (m): 72, 22
Inlets: 1
Outlets: 1
Public Accesses: 2
Table 2. Availability of primary data types for Little Pine Lake.
Data Availability
Transparency data
Excellent data set; consistent monthly (May-September) readings since 1995.
Chemical data
A few sporadic results in the 1980s and consistent data 1997-1998 and 2001-2011.
Inlet/Outlet data
The inlet was monitored in 2001 and 2008-2010.
Recommendations
For recommendations refer to page 19.
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Lake Map
Figure 1. Map of Little Pine Lake with 2010 aerial imagery and illustrations of lake depth contour lines, sample site locations, inlets and outlets, and public access points. The light green areas in the lake illustrate the littoral zone, where the sunlight can usually reach the lake bottom allowing aquatic plants to grow. Table 3. Monitoring programs and associated monitoring sites. Monitoring programs include the Citizen Lake Monitoring Program (CLMP), Minnesota Pollution Control Agency (MPCA), and RMB Environmental Laboratories, Inc (RMBEL).
RMB Environmental Laboratories, Inc 3 of 20 2012 Little Pine Lake
Average Water Quality Statistics The information below describes available chemical data for the primary site (201) of Little Pine Lake through 2011. All parameters with the exception of total phosphorus, chlorophyll a, and Secchi depth, are means for 1980, 1985, and 1986 data.
Minnesota is divided into 7 ecoregions based on land use, vegetation, precipitation, and geology. The MPCA has developed a method of determining the average range of water quality expected for lakes in each ecoregion. For more information and expected water quality ranges, see page 11.
Table 4. Water quality means compared to ecoregion ranges and impaired waters standard.
Parameter
Mean
Ecoregion Range1
Impaired Waters Standard2
Interpretation
Total phosphorus (ug/L) 31 23 - 50 > 40
Results are within the expected range for the ecoregion.
3Chlorophyll a (ug/L) 15 5 - 22 > 14
Chlorophyll a max (ug/L) 50 7 - 37
Secchi depth (ft) 7.7 4.9 - 10.5 < 7
Dissolved oxygen Dimitic
see page 9
Dissolved oxygen depth profiles show that the deep areas of the lake are anoxic in late summer.
Total Kjeldahl Nitrogen
(mg/L)
1.0 <0.60 - 1.2 Indicates insufficient nitrogen to support summer nitrogen-induced algae blooms.
Alkalinity (mg/L) 188 75 – 150 Indicates a low sensitivity to acid rain and a good buffering capacity.
Color (Pt-Co Units) 21 10 - 20 Indicates moderately water with some sediment or coloration
pH 8.3 8.6 - 8.8 Indicates a hard water lake. Lake water pH less than 6.5 can affect fish spawning and the solubility of metals in the water.
Chloride (mg/L) 2.7 4 - 10 Below the expected range for the ecoregion.
Total Suspended Solids
(mg/L)
4.1 2 - 6 Within the expected range for the ecoregion. Indicates low suspended solids and clear water.
Conductivity (umhos/cm) 355 300 - 400 Within the expected range for the ecoregion.
Total Nitrogen :Total
Phosphorus
34:1 25:1 – 35:1 Indicates the lake is phosphorus limited, which means that algae growth is limited by the amount of phosphorus in the lake.
1The ecoregion range is the 25
th-75
th percentile of summer means from ecoregion reference lakes
2For further information regarding the Impaired Waters Assessment program, refer to http://www.pca.state.mn.us/water/tmdl/index.html
3Chlorophyll a measurements have been corrected for pheophytin
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Water Quality Characteristics - Historical Means and Ranges
Table 5. Water quality means and ranges for primary sites.
Parameters Primary
Site 201
Site 202
Site 203
Site 204
Total Phosphorus Mean (ug/L): 31
Total Phosphorus Min: 12
Total Phosphorus Max: 123
Number of Observations: 83
Chlorophyll a Mean (ug/L): 14.7
Chlorophyll a Min: 2
Chlorophyll a Max: 50
Number of Observations: 82
Secchi Depth Mean (ft): 7.7 6.0 7.8 7.7
Secchi Depth Min: 3.5 4.0 3.5 3.0
Secchi Depth Max: 16.0 8.5 14.0 16.0
Number of Observations: 288 65 132 132
Figure 2. Little Pine Lake total phosphorus, chlorophyll a, and transparency historical ranges. The arrow represents the range and the black dot represents the historical mean (Primary Site 201). Figure adapted
after Moore and Thornton, [Ed.]. 1988. Lake and Reservoir Restoration Guidance Manual. (Doc. No. EPA 440/5-88-002)
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Transparency (Secchi Depth) Transparency is how easily light can pass through a substance. In lakes, it is how deep sunlight penetrates through the water. Plants and algae need sunlight to grow, so they are only found in areas of lakes where the sun penetrates. Water transparency depends on the amount of particles in the water. An increase in particulates results in a decrease in transparency. The transparency varies year to year due to changes in weather, precipitation, lake use, flooding, temperature, lake levels, etc. The annual mean transparency for Little Pine Lake ranges from 4.7 to 9.8 feet, and appears relatively uniform throughout the lake. The transparency at sites 201 and 202 was below the long-term mean in the 1980s. Around 1994 the transparency increased and stayed near or above the long-term mean until 2007. Monitoring should be continued annually at site 201 in order to track water quality changes.
Figure 3. Annual mean transparency compared to long-term mean transparency, sites 201, 202, 203, and 204. Little Pine Lake transparency ranges from 3.5 to 16.0 feet at site 201 throughout the summer. Figure 4 shows the seasonal transparency dynamics. The maximum Secchi reading is usually obtained in early summer. Little Pine Lake transparency is high in May and June and declines through August. The transparency then rebounds in October after fall turnover. The dynamics have to do with algae and zooplankton population dynamics, and lake turnover. It is important for lake residents to understand the seasonal transparency dynamics in their lake so they do not worry why their transparency is lower in August than it is in June. It is typical for a lake to vary throughout the summer.
0
2
4
6
8
10
12
Secc
hi D
epth
(ft
)
Transparency: Annual Means
Site 201
Site 202
Site 203
Site 204
mean
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Figure 4. Seasonal transparency dynamics and year to year comparison (Primary Site 201). The black line represents the seasonal pattern of the data.
User Perceptions When volunteers collect Secchi depth readings, they record their perceptions of the water based on the physical appearance and the recreational suitability. These observations can be compared to water quality parameters to see how the lake user would experience the lake at that time. Looking at transparency data, as the Secchi depth decreases the perception of the lake's physical appearance rating decreases. Little Pine Lake was rated as being not quite crystal clear 51% of the time 1995-2011 (site 201).
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Secc
hi D
epth
(ft
) Seasonal Transparency Dynamics 1986
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
Poly. (pattern)
9%
51%
36%
3% 1%
Figure 5. Physical appearance rating, as rated by the volunteer monitor from 1995-2011 (site 201).
9% Crystal clear water 51% Not quite crystal clear – a little algae visible 36% Definite algae – green, yellow, or brown color apparent 3% High algae levels with limited clarity and/or mild odor apparent 1% Severely high algae levels
Physical Appearance Rating
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Figure 7. Historical total phosphorus concentrations (ug/L) for Little Pine Lake.
0
10
20
30
40
50
60
70
Tota
l Ph
osp
ho
rus
(ug
/L)
Total Phosphorus 1996
1997
1998
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
As the Secchi depth decreases, the perception of recreational suitability of the lake decreases. Little Pine Lake was rated as having very minor aesthetic problems 61% of the time from 1995-2011 (site 201).
Total Phosphorus Little Pine Lake is phosphorus limited, which means that algae and aquatic plant growth is dependent upon available phosphorus. Total phosphorus was evaluated in Little Pine Lake in 1996-1998 and 2001-2011. Most of the total phosphorus results fall within the eutrophic range, though some are within the mesotrophic range (Figure 7). The higher phosphorus in spring and fall could be due to lake turnover.
Phosphorus should continue to be monitored to track any future changes in water quality.
9%
61%
25%
5% 0%
Figure 6. Recreational suitability rating, as rated by the volunteer monitor from 1995-2011 (site 201).
9% Beautiful, could not be better 61% Very minor aesthetic problems; excellent for swimming, boating 25% Swimming and aesthetic enjoyment of the lake slightly impaired because of algae levels 5% Desire to swim and level of enjoyment of the lake substantially reduced because of algae levels 0% Swimming and aesthetic enjoyment of the lake nearly impossible because of algae levels
Recreational Suitability Rating
Oligotrophic
Mesotrophic
Eutrophic
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Chlorophyll a is the pigment that makes plants and algae green. It is tested in lakes to determine the algae concentration or how green the water is. Chlorophyll a concentrations greater than 10 ug/L are perceived as a mild algae bloom, while concentrations greater than 20 ug/L are perceived as a nuisance.
Chlorophyll a was evaluated in Little Pine Lake in 1980, 1985, 1986, 1996-1998, and 2001-2011. Early in the year (May and June) the concentrations hover around the 10 mg/L (Figure 8). Some years experienced nuisance algae blooms in midsummer (July and August). In 1996 there were numerous readings above the 20 mg/L.
Dissolved Oxygen
Dissolved Oxygen (DO) is the amount of oxygen dissolved in lake water. Oxygen is necessary for all living organisms to survive, except for some bacteria. Living organisms breathe in oxygen that is dissolved in the water. Dissolved oxygen levels of <5 mg/L are typically avoided by game fisheries. Little Pine Lake is deep, with a maximum depth of 72 feet. Dissolved oxygen profiles from 1958, 1980, 1985, and 1986 indicate that the lake stratifies in the summer, with the thermocline residing at approximately 7-8 meters (23-26 feet). Figure 9 illustrates stratification in the summer of 1980 at site 201. This is a representative DO profile for Little Pine Lake.
Figure 8. Chlorophyll a concentrations (ug/L) for Little Pine Lake.
Figure 9. Dissolved oxygen profile for Little Pine Lake at site 201 in 1980.
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Hypereutrophic
Eutrophic
Mesotrophic
Oligotrophic
100
0
50
40
70
Trophic State Index Phosphorus (nutrients), chlorophyll a (algae concentration), and Secchi depth (transparency) are related. As phosphorus increases, there is more food available for algae, resulting in increased algal concentrations. When algal concentrations increase, the water becomes less transparent and the Secchi depth decreases. The results from these three measurements cover different units and ranges and thus cannot be directly compared to each other or averaged. In order to standardize these three measurements to make them directly comparable, we convert them to a trophic state index (TSI). The mean TSI for site 201 on Little Pine Lake falls in the eutrophic range (50-70) (Figure 10). The TSI for phosphorus and chlorophyll a are similar, which means they are strongly related (Table 6). The transparency (Secchi) TSI is lower than the chlorophyll a TSI. This could be due to zooplankton grazing on the smaller algae cells, large algae particles dominate the algal community, or loss of rooted vegetation. Eutrophic lakes (TSI 50-70) are characteristic of green water most of the summer. "Eu" means true and the root "trophy" means nutrients therefore, eutrophic literally means true nutrients or truly nutrient rich (phosphorus). Eutrophic lakes are usually shallow, and are found where the soils are fertile, and usually have abundant aquatic plants and algae (Table 7). Table 7. Trophic state index attributes and their corresponding fisheries and recreation characteristics. TSI Attributes Fisheries & Recreation
<30 Oligotrophy: Clear water, oxygen throughout
the year at the bottom of the lake, very deep
cold water.
Trout fisheries dominate
30-40 Bottom of shallower lakes may become anoxic
(no oxygen).
Trout fisheries in deep lakes only. Walleye,
Cisco present.
40-50 Mesotrophy: Water moderately clear most of
the summer. May be "greener" in late summer.
No oxygen at the bottom of the lake results in
loss of trout. Walleye may predominate.
50-60 Eutrophy: Algae and aquatic plant problems
possible. "Green" water most of the year.
Warm-water fisheries only. Bass may
dominate.
60-70 Blue-green algae dominate, algal scums and
aquatic plant problems.
Dense algae and aquatic plants. Low water
clarity may discourage swimming and boating.
70-80 Hypereutrophy: Dense algae and aquatic
plants.
Water is not suitable for recreation.
>80 Algal scums, few aquatic plants Rough fish (carp) dominate; summer fish kills
possible Source: Carlson, R.E. 1997. A trophic state index for lakes. Limnology and Oceanography. 22:361-369.
Trophic State Index Site 201
TSI Total Phosphorus 54
TSI Chlorophyll-a 57
TSI Secchi 48
TSI Mean 53
Trophic State: Eutrophic
Numbers represent the mean TSI for each parameter.
Little Pine
Lake
Table 6. Trophic State Index for site 201.
Figure 10. Trophic state index chart with corresponding trophic status.
RMB Environmental Laboratories, Inc 10 of 20 2012 Little Pine Lake
Trend Analysis For detecting trends, a minimum of 8-10 years of data, with 4 or more readings per season, are recommended. Minimum confidence accepted by the MPCA is 90%. This means that there is a 90% chance that the data are showing a true trend and a 10% chance that the trend is a random result of the data. Only short-term trends can be determined with just a few years of data, because there can be different wet years and dry years, water levels, weather, etc., that affect the water quality naturally. There is enough historical data to perform trend analysis for on Little Pine Lake. Site 201 has 17 years of transparency data, and 14 years of chlorophyll a and total phosphorus data. This was enough numerical information to perform a long-term trend report (Table 8) using the Mann Kendall Trend Analysis. Table 8. Trend analysis for Little Pine Lake.
Lake Site Parameter Date Range Trend
201 Transparency 1995-2011 No trend
201 Chlorophyll a 1996-1998, 2001-2011 No trend
201 Total Phosphorus 1996-1998, 2001-2011 No trend
Figure 11. Transparency (ft) trend for site 201.
Site 201 shows no significant trend in transparency, chlorophyll a, or total phosphorus. This indicates the water quality on Little Pine Lake is staying the same. Transparency monitoring should continue so this trend can be tracked in future years.
0
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hi D
epth
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Transparency Trend for Little Pine Lake
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increased algae
Ecoregion Comparisons Minnesota is divided into 7 ecoregions based on land use, vegetation, precipitation, and geology (Figure 12). The MPCA has developed a way to determine the average range of water quality expected for lakes in each ecoregion. From 1985-1988, the MPCA evaluated the lake water quality for reference lakes. These lakes are not considered pristine, but have little human impact and therefore are representative of the typical lakes within the ecoregion. The average range refers to the 25th - 75th percentile range for data within each ecoregion. For the purpose of this graphical representation, the means of the reference lake data sets were used. Little Pine Lake is in the Central Hardwood Forest Ecoregion. The mean total phosphorus, chlorophyll a, and transparency (Secchi depth) for Little Pine Lake are all within the expected ecoregion ranges (Figure 13).
Figures 13a-c. Little Pine Lake ranges compared to Central Hardwood Forest ranges. The Little Pine Lake total phosphorus and chlorophyll a ranges are from 81 data points collected in May-September of 1980, 1985, 1986, 1996-1998, and 2001-2011. The Secchi depth range is from 288 data points collected in May-September from 1980, 1985, 1986, and 1995-2011.
0
20
40
60
80
100
120
CHF Ecoregion
Little Pine
To
tal P
ho
sp
ho
rus
(p
pb
)
0
10
20
30
40
50
60
70
CHF Ecoregion
Little Pine
Ch
loro
ph
yll
-a (
pp
b)
0
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16
18
20
Secch
i d
ep
th (
ft)
crystal
clear
Figure 12. Minnesota Ecoregions.
CHF Ecoregion
Little Pine
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Lakeshed Data and Interpretations
Lakeshed Understanding a lakeshed requires an understanding of basic hydrology. A watershed is defined as all land and water surface area that contribute excess water to a defined point. The MN DNR has delineated three basic scales of watersheds (from large to small): 1) basins, 2) major watersheds, and 3) minor watersheds. The Otter Tail River Major Watershed is one of the watersheds that make up the Red River Basin, which drains north to Lake Winnipeg (Figure 14). This major watershed is made up of 106 minor watersheds. Little Pine Lake is located in minor watershed 56014 (Figure 15).
The MN DNR also has evaluated catchments for each individual lake with greater than 100 acres surface area. These lakesheds (catchments) are the building blocks for the larger scale watersheds. Little Pine falls within lakeshed 5601400 (Figure 16). Though very useful for displaying the land and water that contribute directly to a lake, lakesheds are not always true watersheds because they may not show the water flowing into a lake from upstream streams or rivers. While some lakes may have only one or two upstream lakesheds draining into them, others may be connected to many, reflecting a larger drainage area via stream or river networks. For further information, containing all the upstream lakesheds, see page 17. The data interpretation of the Little Pine lakeshed includes only the land surface that flows directly into the lake. The lakeshed vitals table identifies where to
Figure 14. Otter Tail River Watershed. Figure 15. Minor Watershed 56014.
Figure 16. Little Pine Lakeshed (5601400) with land ownership, lakes, county lines, and wetlands illustrated.
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focus organizational and management efforts for each lake (Table 9). Criteria were developed using limnological concepts to determine the effect to lake water quality. KEY
Possibly detrimental to the lake Warrants attention
Beneficial to the lake Table 9. Little Pine Lake lakeshed vitals table.
Lakeshed Vitals Rating Lake Area 2080 acres descriptive
Littoral Zone Area 764 acres descriptive
Lake Max Depth 72 feet descriptive
Lake Mean Depth 24 feet NA
Water Residence Time NA NA
Miles of Stream None descriptive
Inlets 1
Outlets 1
Major Watershed 56-Otter Tail River descriptive
Minor Watershed 56014 descriptive
Lakeshed 5601400 descriptive
Ecoregion North Central Hardwood Forests descriptive
Total Lakeshed to Lake Area Ratio (total
lakeshed includes lake area) 2:1
Standard Watershed to Lake Basin Ratio (standard watershed includes lake areas)
120:1
Wetland Coverage 6.6%
Aquatic Invasive Species None as of 2011
Public Drainage Ditches None
Public Lake Accesses 2
Miles of Shoreline 7.3 miles descriptive
Shoreline Development Index 1.1
Public Land to Private Land Ratio 0.07:1
Development Classification General Development
Miles of Road 14.1 descriptive
Municipalities in lakeshed Perham
Forestry Practices No county forest plan
Feedlots 1
Sewage Management
Lake Management Plan None
Lake Vegetation Survey/Plan None
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Figure 17. The Little Pine Lake (5601400) lakeshed land cover (http://land.umn.edu).
Land Cover / Land Use
The activities that occur on the land within the lakeshed can greatly impact a lake. Land use planning helps ensure the use of resources in an organized fashion so the needs of the present and future generations can be best addressed. The purpose of land use planning is to ensure acreage will be used in a manner that provides maximum social benefits without degrading the land resource. Changes in land use, and ultimately land cover, impact the hydrology of a lakeshed. Cover is directly related to the land’s ability to absorb and store water, rather than cause it to flow overland (gathering nutrients and sediment as it moves) towards the lowest point on the landscape. Impervious intensity describes the lands inability to absorb water, the higher the % impervious intensity the more area that water cannot penetrate in to the soils. Monitoring the changes in land use can assist in future planning procedures to address the needs of future generations. Phosphorus export, which is the main cause of lake eutrophication, depends on the type of land cover occurring in the lakeshed. Figure 17 depicts the land cover in Little Pine lakeshed. The University of Minnesota has online records of land cover statistics from years 1990 and 2000 (http://land.umn.edu). Even though this data is 12 years old, it is the only data set available for comparing land use over a decade’s time. Table 10 describes Little Pine Lake’s lakeshed land cover statistics and percent change from 1990 to 2000. Due to the many factors that influence demographics, one cannot determine with certainty the projected statistics over the next 10, 20, 30+ years, but one can see the transition within the lakeshed from agriculture, grass/shrub/wetland, and water acreages to forest and urban acreages. The largest change in percentage is the increase in forest cover (78%). In addition, the impervious intensity has increased, which has implications for storm water runoff into the lake. The increase in impervious intensity is consistent with the increase in urban acreage.
Demographics Little Pine Lake is classified as a general development lake. These types of lakes usually have more than 225 acres of water per mile of shoreline, 25 dwellings per mile of shoreline, and are more than 15 feet deep. The Minnesota Department of Administration Geographic and Demographic Analysis Division extrapolated the future population of the area, in 5-year increments, out to 2035. Compared to Otter Tail County as a whole, City of Perham and Perham Township have a higher extrapolated growth projection. Corliss Township has a similar extrapolated growth projection and Gorman Township has a lower extrapolated growth projection (Figure 18). Figure 18. Population growth projection for City of Perham, Perham, Corliss and Gorman Townships, and Otter Tail County. (source: http://www.demography.state.mn.us/resource.html?Id=19332)
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Little Pine Lakeshed Water Quality Protection Strategy Each lakeshed has a composition of public and private lands. Looking in more detail at the makeup of these lands can give insight on where to focus protection efforts. The protected lands (easements, wetlands, and public land) are the future water quality infrastructure for the lake. Developed land and agriculture have the highest phosphorus runoff coefficients, so this land should be minimized for water quality protection. The majority of the land within Little Pine lakeshed is made up of private agricultural land (Table 11). This land can be the focus of development and protection efforts in the lakeshed. Table 11. Land ownership, land use/land cover, estimated phosphorus loading, and ideas for protection and restoration in Little Pine lakeshed (Sources: Otter Tail County parcel data, National Wetlands Inventory, and the 2006 National Land Cover Dataset).
Private (53%) 43% Public (4%)
Developed Agriculture
Forested Uplands Other Wetlands
Open Water County State Federal
Land Use (%) 3.1% 32.9% 7.7% 2.8% 6.5% 43% 3.8% 0.2% 0%
Runoff Coefficient
Lbs of phosphorus/acre/
year
0.45 - 1.5 0.26 - 0.9 0.09 0.09 0.09 0.09 0.09
Estimated Phosphorus Loading Acerage x runoff coefficient
66–221 413–1429 33 28 15 <1 0
Description Focused on Shoreland
Cropland
Focus of develop-ment and protection
efforts
Open, pasture, grass-land,
shrub-land
Protected
Potential Phase 3 Discussion Items
Shoreline restoration
Restore wetlands;
CRP
Forest stewardship planning, 3
rd
party certification, SFIA, local woodland
cooperatives
Protected by
Wetland Conservation
Act
County
Tax Forfeit Lands
State Forest
National Forest
DNR Fisheries approach for lake protection and restoration
Credit: Peter Jacobson and Michael Duval, Minnesota DNR Fisheries
In an effort to prioritize protection and restoration efforts of fishery lakes, the MN DNR has developed a ranking system by separating lakes into two categories, those needing protection and those needing restoration. Modeling by the DNR Fisheries Research Unit suggests that total phosphorus concentrations increase significantly over natural concentrations in lakes that have watershed with disturbance greater than 25%. Therefore, lakes with watersheds that have less than 25% disturbance need protection and lakes with more than 25% need restoration (Table 12). Watershed disturbance was defined as having urban, agricultural, and mining land uses. Watershed protection is defined as publicly owned land or conservation easement.
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Table 12. Suggested approaches for watershed protection and restoration of DNR-managed fish lakes in Minnesota.
Watershed Disturbance
(%)
Watershed Protected
(%)
Management Type
Comments
< 25%
> 75% Vigilance Sufficiently protected -- Water quality supports healthy and diverse native fish communities. Keep public lands protected.
< 75% Protection
Excellent candidates for protection -- Water quality can be maintained in a range that supports healthy and diverse native fish communities. Disturbed lands should be limited to less than 25%.
25-60% n/a Full Restoration Realistic chance for full restoration of water quality and improve quality of fish communities. Disturbed land percentage should be reduced and BMPs implemented.
> 60% n/a Partial Restoration
Restoration will be very expensive and probably will not achieve water quality conditions necessary to sustain healthy fish communities. Restoration opportunities must be critically evaluated to assure feasible positive outcomes.
The next step was to prioritize lakes within each of these management categories. DNR Fisheries identified high value fishery lakes, such as cisco refuge lakes. Ciscos (Coregonus artedi) can be an early indicator of eutrophication in a lake because they require cold hypolimnetic temperatures and high dissolved oxygen levels. These watersheds with low disturbance and high value fishery lakes are excellent candidates for priority protection measures, especially those that are related to forestry and minimizing the effects of landscape disturbance. Forest stewardship planning, harvest coordination to reduce hydrology impacts, and forest conservation easements are some potential tools that can protect these high value resources for the long term.
Little Pine lakeshed is classified as having 43.3% of the watershed protected and 40.4% of the watershed disturbed (Figure 19), therefore, the area should have a full restoration focus. Goals for the lake should be to limit any increase in disturbed land use and implement best management practices.
Figure 20 displays the upstream lakesheds that contribute water to the lakeshed of interest. All of the land and water area in this figure has the potential to contribute water to Little Pine Lake, whether through direct overland flow or through a creek or river. Thirty of the 86 upstream lakesheds have the same management focus (full restoration).
Percent of the Watershed Protected
Percent of the Watershed with Disturbed Land Cover
0% 100% 75%
Little Pine Lake (43.3%)
0% 100% 25%
Little Pine Lake (40.4%)
Figure 19. Little Pine lakeshed’s percentage of watershed protected and disturbed.
Figure 20. Upstream lakesheds that contribute water to the Little Pine lakeshed. Color-coded based on management focus (Table 12).
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Little Pine Lake, Status of the Fishery (as of 06/27/2011)
Little Pine Lake is a 1,969-acre mesotrophic (moderately fertile) lake located in northeastern Otter Tail County, approximately two miles north of Perham, MN. It is a part of the Otter Tail River Watershed and is connected to Big Pine Lake via the Otter Tail River. The river inlet is located along the west shoreline of the lake while the outlet is located along the southeast shoreline. The Otter Tail River is navigable by boat upstream of Little Pine Lake. A Minnesota DNR-controlled dam at the outlet impedes navigability downstream to Big Pine Lake.
The immediate watershed is composed primarily of agricultural land interspersed with hardwood woodlots, however, there has recently been an increase in residential development. The maximum depth of Little Pine Lake is 63 feet; however, thirty-five percent of the lake is less than 15 feet in depth. The Secchi disk reading during the 2011 lake survey was 9.0 feet. Previous Secchi disk readings ranged from 5.5 to 18.5 feet. The shoreline of Little Pine Lake has been extensively developed, composed primarily of homes, cottages, and resorts. A DNR-owned concrete public access is located off of County Road 8, along the southeast shoreline of the lake. A city-owned (Perham) concrete public access is located off of County Road 51 along the west shoreline of the lake.
Remnant stands of hardstem bulrush and common cattail are located in the area near the Otter Tail River inlet. Emergent aquatic plants such as these, provide valuable fish and wildlife habitat, and are critical for maintaining good water quality. Emergent plants provide spawning areas for fish such as northern pike, largemouth bass, and panfish. They also serve as important nursery areas for all species of fish. Because of their ecological value, emergent plants may not be removed without a DNR permit. To maintain the excellent water quality and angling, it is imperative high quality aquatic habitat is preserved.
Little Pine Lake is a popular angling lake during both open water and ice fishing seasons. The lake has a reputation as a premier walleye fishing lake in Otter Tail County. Northern pike and yellow perch are also abundant and have good size distributions. The prolificacy of these species can be attributed to the abundance of suitable spawning habitat. Walleye is the primary management specie in Little Pine Lake. Ranging in length from 7.1 to 25.6 inches, they have an average length and weight of 15.0 inches and 1.4 pounds. Age and catch data from recent lake surveys indicate that walleye natural reproduction is substantial enough to maintain the population at or above DNR long range management goals. Walleye exhibit moderate growth rates with an average length of 14.9 inches at four years of age. An experimental walleye regulation was implemented on May 10, 2003, with the intent of improving size structure within the lake population. The regulation is an 18.0 to 26.0 protected slot limit with one walleye over 26.0 inches allowed in possession. The regulation will be in effect for ten years, during which time its effectiveness will be evaluated.
Northern pike abundance is the highest recorded for this lake, exhibiting good size distribution and above average growth rates. Pike ranged in length from 10.7 to 33.5 inches, with an average length and weight of 20.2 inches and 1.9 pounds. Fourteen percent of the pike were at least 24.0 inches in length, and have attained an average length of 24.6 inches at four years of age.
See the link below for specific information on gillnet surveys, stocking information, and fish consumption guidelines. http://www.dnr.state.mn.us/lakefind/showreport.html?downum=56014200
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Key Findings / Recommendations Monitoring Recommendations Transparency monitoring at site 201 should be continued annually. It is important to continue transparency monitoring weekly, or at least bimonthly, every year to enable annual comparisons and trend analyses. Total phosphorus and chlorophyll a monitoring should continue, as the budget allows, tracking future trends. Overall Conclusions Little Pine Lake is in fair shape regarding water quality, but the lakeshed needs restoration from disturbed land uses. Little Pine Lake is a eutrophic lake (TSI=53) with no trends in water quality. Four percent (4%) of the lakeshed is in public ownership, and 43% is protected, while 40% of the lakeshed is disturbed (Figure 19). The dissolved oxygen (Figure 9) and total phosphorus (Figure 7) data show that there could be internal loading occurring in areas of the lake that are less than 30 feet deep. The chlorophyll a data shows nuisance algae blooms occur in August and September (Figure 8). Little Pine Lake has a very large watershed, with a ratio of watershed area to lake area of 120:1 (Table 9). Much of the upstream watershed has agricultural crop land, which drains to the Otter Tail River. Priority impacts to the lake Agricultural land use in the lakeshed is high (33%), and is the reason for the lakeshed being classified as full restoration (Table 12, Figure 20). Shoreline buffers are thin in many farmed sections (especially the north side), so nutrient and sediment runoff from agricultural lands into the lake and into the stream inlets may affect water quality. The agricultural uses include pasture/hay, cultivated crops and animal feedlots. There is a high degree of development pressure on Little Pine Lake, due to its proximity to the City of Perham. From 1990-2000, the urban area in the lakeshed increased by 47% (87 acres), and the impervious area increased by 37 acres (Table 10). Continued expansion and development of residential lots adjacent to the City of Perham (the south side of the lake), conversion of previously farmed land to housing, and 2nd tier development along the lakeshore are concerns for Little Pine Lake. The population in the townships surrounding the lake is projected to grow another 10-15% in the next 10 years (Figure 18). Storm water runoff from impervious surface from developed shoreline properties and road are priority impacts. Best Management Practices Recommendations The management focus for Little Pine Lake should protect the current water quality, and restore and protect additional acreage within the lakeshed. Partnering with farmers to implement conservation farming practices, increase lake and stream shoreline buffers, or place priority parcels into land retirement programs can decrease the impacts of agriculture. Protection efforts should be also focused on managing and/or decreasing the impact caused by additional development, including second tier development, and impervious surface area. Project ideas include protecting land with conservation easements, enforcing county shoreline ordinances, smart development, shoreline restoration, rain gardens, and septic system maintenance. Although it may not be possible to decrease the impervious area in the lakeshed, it is possible to reduce the impact of the impervious surface by retaining storm water instead of allowing it to runoff into the lake. Managing storm water through rain gardens, holding ponds, and shoreline restoration would benefit the lake.
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Organizational contacts and reference sites
Pine Lakes Improvement District http://www.pinelakeslid.com/LID/Home.html
