Portage, Crooked, Sugar, and Hanks Lakes
Lake Water Quality
Summary
Portage, Crooked, Sugar, and Hanks Lakes are located 13 miles east of
Brainerd, MN in Crow Wing County. They are all connected as a group of lakes.
The group of lakes has an inlet and outlet, which classify them as drainage
lakes. The inlet enters Portage Lake on the south side and flows north into
Hanks Lake, and exits Sugar Bay on the northeast side (Figure 1). From there,
the water flows through Maple Lake and into Bay Lake. There are no direct
inlets to Crooked Lake; it just has a connection to Sugar Bay.
Water quality data have been collected on these lakes since 1974. These data
show that the lakes are at the oligotrophic/mesotrophic border (TSI 39-41), which is characteristic of
clear water throughout the summer and excellent recreational opportunities.
The Portage, Crooked, Sugar, and Hanks Lake Association’s purpose is to “preserve and improve the
condition and quality of our lakes and the surrounding area. We strive to create a spirit of cooperation
and community with all property owners on the chain of lakes”. The Association has been involved in
numerous activities including water quality monitoring and education of their members.
Table 1. Portage, Crooked and Hanks Lakes location and key physical characteristics.
Location Data
Physical Characteristics
MN Lake ID: Portage
18-0050-00
MN Lake ID: Crooked
18-0041-02
MN Lake ID: Sugar Bay 18-0041-01
Portage
Crooked &
Hanks
Sugar Bay
Surface area (acres):
286
358
164
Littoral area (acres):
116
187
48
MN Lake ID: Hanks
18-0044-00
% Littoral area:
40%
52%
29%
County:
Crow Wing
Max depth (ft), (m):
37, 11.3
72, 22
45, 13.7
Ecoregion:
Northern Lakes and Forests
Inlets:
1
None
1
Major Drainage Basin:
Upper Mississippi River
Outlets:
1
1
1
Latitude/Longitude:
46.35416667 / -93.91694444
Public Accesses:
None
1
None
Invasive Species:
None as of 2011
Table 2: Availability of data and an observation of the quantity of sample points.
Data Availability
Transparency data
Excellent data set through the Citizens Lake Monitoring
Program (CLMP).
Chemical data
Good phosphorus and chlorophyll data set, but not enough
for a trend analysis (need 8-10 consecutive years).
Inlet/Outlet data
No data exist, but this monitoring is low priority due to
improving water quality trends and a small watershed.
Recommendations
For recommendations refer to page 21.
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Lake Map
Figure 1. Map of Portage, Crooked and Hanks Lakes with 2010 aerial imagery and illustrations of lake depth
contour lines, streams/rivers, sample site locations, inlets and outlets, and public access points. The green
shaded areas in the lake illustrate the littoral zone, where the sunlight can usually reach the lake bottom
allowing aquatic plants to grow.
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Table 3. Monitoring programs and associated monitoring sites. (CLMP: Citizens Lake Monitoring Program;
MPCA: Minnesota Pollution Control Agency; RMBEL: RMB Environmental Laboratories Lakes Program; CWC:
Crow Wing County)
Lake
Lake Site
Depth
(ft)
Portage
201 *primary
35
CLMP: 1974, 1978-1982, 1985, 1991-1997, 1999-2011; MPCA:
1979, 1981, 2004; RMBEL: 2007-2010
Portage
202
26
CLMP: 1980, 1988; MPCAL 1980-1981
Portage
203
27
CLMP: 2005-2010
Crooked
101 *primary
45
MPCA: 1989-1990, 2004; RMBEL: 2008-2010
Crooked
102
25
MPCA: 1989-1990
Crooked
201
40
CLMP: 1974, 1989-1991, 1994, 1996,2001, 2004-2010
Crooked
202
25
CLMP: 1978-1991, 1994. 1996, 2001, 2004-2010
MPCA: 1979-1981
Crooked
203
40
CLMP: 1978-1991, 1994, 1996, 2001, 2004-2006, 2008-2010;
MPCA: 1979-1981
Crooked
204
15
CLMP: 1979, 1989-1991, 1994, 1996, 2004-2006, 2008-2010,
MPCA: 1979
Crooked
205
60
CLMP: 2003-2010; CWC: 2003
Sugar Bay
201 *primary
30
CLMP: 1974, 1980-1987, 1990, 2003-2011; MPCA: 1990, 2004;
RMBEL: 2008-2010
Sugar Bay
202
17
MPCA: 1988-1989, 1991
Hanks
201 *primary
35
CLMP: 1974, 1980-1989, 1991, 2008-2010; RMBEL: 2008-2010
Hanks
202
35
CLMP: 2003-2010; MPCA: 1990, 2004
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Average Water Quality Statistics
The information below describes available chemical data for the primary sites of the chain of lakes
through 2011. The data set is limited, and all parameters with the exception of total phosphorus,
chlorophyll a and secchi depth, are means for just 1989-1990 data.
Minnesota is divided into 7 ecoregions based on land use, vegetation, precipitation and geology. The
MPCA has developed a way to determine the "average range" of water quality expected for lakes in
each ecoregion. For more information on ecoregions and expected water quality ranges, see page
10.
Table 4. Water quality means compared to ecoregion ranges and impaired waters standard.
Parameter
Portage
Crooked
Sugar
Bay
Hanks
Ecoregion
Range1
Total
phosphorus
15
11
12
11
14 - 27
4
3
4
3
4 - 10
Chlorophyll a
max (ug/L)
16
10
11
5
<15
Secchi depth (ft)
11.7
15
12.3
11.3
7.5 - 15
Dissolved
oxygen
Dimictic
Dimictic
Dimictic
Dimictic
Total Kjeldahl
Nitrogen (mg/L)
0.49
0.68
0.58
0.68
0.4 - 0.75
Indicates insufficient nitrogen to
support summer nitrogen-induced
algae blooms.
Alkalinity (mg/L)
97
76
81
88
40 - 140
Indicates a low sensitivity to acid
rain and a good buffering capacity.
Color (Pt-Co
11
9
9
9
10 - 35
Indicates clear water with little to no
tannins (brown stain).
pH
8.0
8.1
8.0
8.0
7.2 - 8.3
Within the expected range for the
ecoregion. Lake water pH less than
6.5 can affect fish spawning and the
solubility of metals in the water.
Chloride (mg/L)
6.2
3.0
3.4
4.0
0.6 - 1.2
Higher than the expected range for
the ecoregion, but still considered
low level
Total
Suspended
Solids (mg/L)
1.6
1.6
1.8
1.4
<1 - 2
Indicates low suspended solids and
clear water.
Specific
Conductance
188
145
174
187
50 - 250
Within the expected range for the
ecoregion.
21:1
60:1
48:1
60:1
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.
Interpretation
(ug/L)
3
Chlorophyll a
(ug/L)
Crooked, Sugar Bay and Hanks are
better than the expected range for
the ecoregion, while Portage is
within the ecoregion range.
Dissolved oxygen depth profiles
show that the deep areas of the lake
are anoxic in late summer.
Units)
(umhos/cm)
Total Nitrogen:
Total Phosphorus
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Water Quality Characteristics - Historical Means and Ranges
Table 5. Water quality means and ranges for primary sites.
Parameters
Total Phosphorus Mean (ug/L):
Total Phosphorus Min:
Total Phosphorus Max:
Number of Observations:
Chlorophyll a Mean (ug/L):
Chlorophyll-a Min:
Chlorophyll-a Max:
Number of Observations:
Secchi Depth Mean (ft):
Secchi Depth Min:
Secchi Depth Max:
Number of Observations:
Portage
Site 201
Crooked
Site 101
Sugar Bay
Site 201
Hanks
Site 201
15
5
52
42
4
1
16
34
11.7
5.5
21.5
240
11
8
119
45
3
1
10
34
15
10.0
22.0
28
12
8
78
39
4
1
11
39
12.3
6.5
18.0
160
11
7
22
20
3
1
5
20
11.3
7.0
19.0
122
Figure 2. Portage, Crooked, Sugar Bay, Hanks Lakes total phosphorus, chlorophyll a and transparency
historical ranges. The black dot represents the historical mean for each primary site. 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 able to grow
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 between all lakes ranges from 10 to 18 feet. The transparency is very
similar for all four lakes, while Crooked Lake is consistently the highest. This makes sense because
Crooked Lake is the deepest lake of the four. The lakes follow the same ups and downs, showing
seasonal variability. Transparency monitoring should be continued annually in each lake in order to
track water quality changes.
20
Transparency: Annual Means
18
Secchi Depth (ft)
16
14
12
10
8
Portage
6
Crooked
4
Sugar Bay
2
Hanks
0
Figure 3. Annual mean transparency compared to long-term mean transparency.
Figures 4-7 show the seasonal transparency dynamics for all four lakes. All the lakes’ transparency
remain fairly consistent throughout the summer. This is common in lakes with good clarity and low
algae concentrations. Some lakes vary throughout the summer while some lakes stay constant. The
dynamics have to do with algae population dynamics and lake turnover.
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Seasonal Transparency Dyanmics, Crooked
2001
Secchi Depth (ft)
25
2004
20
2005
15
2006
2008
10
2009
5
2010
0
pattern
Poly. (pattern)
Figure 4. Seasonal transparency dynamics and year to year comparison for Crooked Lake (Site 201). The black
line represents the pattern in the data.
Secchi Depth (ft)
Seasonal Transparency Dynamics, Sugar Bay
20
18
16
14
12
10
8
6
4
2
0
2003
2004
2005
2006
2007
2008
2009
2010
2011
pattern
Secchi Depth (ft)
Figure 5. Seasonal transparency dynamics and year to year comparison for Sugar Bay (Site 201). The black line
represents the pattern in the data.
20.0
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
Seasonal Transparency Dynamics, Hanks
2008
2009
2010
2011
pattern
Poly. (pattern)
Figure 6. Seasonal transparency dynamics and year to year comparison for Hanks Lake (Site 201). The black
line represents the pattern in the data.
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Seasonal Transparency Dynamics, Portage
25
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
pattern
Poly. (pattern)
Secchi Depth (ft)
20
15
10
5
0
Figure 7. Seasonal transparency dynamics and year to year comparison for Portage Lake (Site 201). The black
line represents the pattern in 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
perceptions 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.
Portage
9%
Physical Appearance Rating
Crystal clear water
Not quite crystal clear – a little algae visible
Definite algae – green, yellow, or brown color
apparent
High algae levels with limited clarity and/or mild
odor apparent
Severely high algae levels
Crooked
Hanks
Sugar
13%
1%
31%
44%
56%
69%
78%
80%
Figure 8. Physical appearance rating, as rated by the volunteer monitors.
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19%
Recreational Suitability Rating
All of the lakes were rated as having
crystal clear or not quite crystal clear
water most of the summer (Figure
8).
As the secchi depth decreases, the
perception of recreational suitability
of the lake decreases. All the lakes
were rated as beautiful or having
very minor aesthetic problems most
of the time (Figure 9).
8%
Portage
89%
Beautiful, could not be better
10%
Very minor aesthetic problems; excellent for
swimming, boating
1%
Swimming and aesthetic enjoyment of the lake
slightly impaired because of algae levels
0%
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
Crooked
34
%
Sugar
Hanks
46%
100%
45%
55%
58
%
54%
Figure 9. Recreational suitability rating, as rated by the volunteer monitors.
Total Phosphorus
Portage, Crooked, Sugar
Bay and Hanks Lakes are
phosphorus limited, which
means that algae and
aquatic plant growth is
dependent upon available
phosphorus.
Total Phosphorus (ug/L)
Total phosphorus was
evaluated in these lakes on
the same dates in 20082011, which makes for great
comparison (Figure 10).
Portage Lake has
consistently the highest
phosphorus, while Hanks
has consistently the lowest.
All the lakes are fairly similar,
however.
Total Phosphorus
30
25
20
Portage
15
Crooked
10
Sugar Bay
Hanks
5
0
Figure 10. Historical total phosphorus concentrations (ug/L) for Portage,
Crooked, Sugar Bay and Hanks Lakes.
Phosphorus should
continue to be monitored to track any future changes in water quality.
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Chlorophyll a
Chlorophyll a is the
pigment that makes
plants and algae
green. Chlorophyll a
is tested in lakes to
determine the algae
concentration or how
"green" the water is.
18
Chlorophyll a
Chlorophyll a (ug/L)
16
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.
14
12
Portage
10
Crooked
8
Sugar Bay
6
Hanks
4
Minor Algae
2
0
Chlorophyll a was
Figure 11. Chlorophyll a concentrations (ug/L) for Portage, Crooked, Sugar Bay,
evaluated in
and Hanks Lakes.
Portage, Crooked,
Sugar Bay and Hanks Lakes on the same dates from 2008-2011 (Figure 11). Portage, Crooked and
Sugar Bay reached 10 ug/L once each, indicating minor algae blooms. Hanks never reached 10 ug/L
in the years monitored.
Dissolved Oxygen
Dissolved Oxygen (mg/L)
0
2
4
6
8
10
0
1
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.
2
Portage, Crooked, Sugar and Hanks Lakes are all relatively deep
lakes, with maximum depths ranging from 40-70 feet. Dissolved
oxygen profiles from 2004 indicate that all the lakes stratify during
the summer. The thermocline appears to be at a similar depth in
each lake, 6-7 meters (20-23 ft), which means that gamefish will be
scarce below that depth. Figure 12 shows representative dissolved
oxygen profiles for each lake.
3
4
5
Depth (m)
6
7
9
11
13
Portage
Crooked
14
15
19
Sugar
Hanks
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Figure 12. Dissolved oxygen profiles for Portage,
Crooked, Sugar, and Hanks Lakes in the summer
of 2004.
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Trophic State Index
Table 6. Trophic States for Portage, Crooked, Sugar and Hanks lakes.
Phosphorus (nutrients),
Trophic State Index Portage
Crooked Sugar Bay Hanks
chlorophyll a (algae
TSI Total Phosphorus 40
39
40
38
concentration) and Secchi
TSI
Chlorophyll-a
44
43
43
41
depth (transparency) are
TSI Secchi
40
38
39
42
related. As phosphorus
increases, there is more
TSI Mean
41
40
41
40
food available for algae,
On the border between oligotrophic and mesotrophic
Trophic State:
resulting in increased algal
Numbers represent the mean TSI for each parameter.
concentrations. When algal
concentrations increase, the water becomes less
transparent and the Secchi depth decreases.
100
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).
Hypereutrophic
70
Eutrophic
50
The mean TSI for all 4 lakes falls
Portage, Crooked,
on the border between oligotrophic
Sugar, Hanks Lakes
and mesotrophic (39-41) (Figure
13). There is good agreement
between the TSI for phosphorus,
chlorophyll a and transparency, indicating that these
variables are strongly related. In addition, all lakes are
relatively similar in TSI (Table 6).
Lakes on the oligotrophic/mesotrophic border (TSI 3941) are characteristic of clear water throughout the
summer and are excellent for recreation (Table 7).
Mesotrophic
40
Oligotrophic
0
Figure 13. Trophic state index chart with
corresponding trophic status.
Table 7. Trophic State Index categories and corresponding lake conditions.
TSI
Attributes
Fisheries & Recreation
<30
Oligotrophy: Clear water, oxygen throughout
Trout fisheries dominate
the year at the bottom of the lake, very deep
cold water.
30-40
Bottom of shallower lakes may become anoxic
Trout fisheries in deep lakes only. Walleye,
(no oxygen).
Cisco present.
40-50
Mesotrophy: Water moderately clear most of
No oxygen at the bottom of the lake results in
the summer. May be "greener" in late summer.
loss of trout. Walleye may predominate.
50-60
Eutrophy: Algae and aquatic plant problems
Warm-water fisheries only. Bass may
possible. "Green" water most of the year.
dominate.
60-70
Blue-green algae dominate, algal scums and
Dense algae and aquatic plants. Low water
aquatic plant problems.
clarity may discourage swimming and boating.
70-80
Hypereutrophy: Dense algae and aquatic
Water is not suitable for recreation.
plants.
>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.
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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 transparency data to perform a trend analysis in transparency on each of the four
lakes (Table 8). The data was analyzed using the Mann Kendall Trend Analysis.
Table 8. Trend analysis results for Portage, Crooked, Sugar and Hanks Lakes.
Lake Site
Parameter
Date Range
Trend
Probability
Portage
Transparency
1991-1997, 1999-2011
Improving
95%
Crooked
Transparency
2001, 2004-2010
Improving
95%
Sugar Bay
Transparency
2003-2011
Improving
95%
Hanks
Transparency
1980-1989, 1991, 2008, 2009, 2010
Improving
95%
All four lakes show an improving trend in transparency (Table 8). Transparency monitoring should
continue in each lake so that these trends can be tracked in future years.
Ecoregion Comparisons
Minnesota is divided into 7 ecoregions based on land
use, vegetation, precipitation and geology (Figure
14). 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 reference lakes are not considered pristine,
but are considered to 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.
All four lakes are within or slightly better than the
expected ecoregion ranges (Figure 15). Crooked has
the best transparency, which makes sense because it
is the deepest and largest.
Figure 14. Map of Minnesota with the
seven ecoregions.
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60
25
50
15
10
0
5
40
Secchi depth (ft)
20
Total Phosphorus (ug/L, ppb)
Chlorophyll-a (ug/L, ppb)
30
30
20
5
10
0
0
10
15
20
25
Figures 15a-c. Portage, Crooked, Sugar Bay and Hanks Lakes compared to the Northern Lakes and Forest
Ecoregions.
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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 Mississippi River - Brainerd Major Watershed is one of the watersheds that make up the
Upper Mississippi River Basin, which drains south to the Gulf of Mexico (Figure 16). This major
watershed is made up of 128 minor watersheds. Portage, Crooked and Hanks Lake are located in
minor watershed 10035 (Figure 17).
Figure 16. Mississippi River - Brainerd Watershed.
Figure 17. Minor Watershed 10035.
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. Portage, Crooked,
Sugar and Hanks Lakes fall into
three different lakesheds (Figure
16). Though very useful for
displaying the land and water that
contribute directly to a lake,
lakesheds are not true watersheds
because they do 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 a large number
of lakesheds, reflecting a larger
drainage area via stream or river
networks.
Figure 18. Lakesheds for Portage,
Crooked, and Hanks Lakes.
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The lakeshed vitals table identifies where to 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. Lakeshed vitals for Portage, Crooked, Sugar, and Hanks Lakes.
Lakeshed Vitals
Portage
Crooked & Sugar
Hanks
Rating
Lake Area
Littoral Zone Area
Lake Max Depth
Lake Mean Depth
Water Residence Time
Miles of Stream
Inlets
Outlets
Lakeshed
Total Lakeshed to Lake Area Ratio (total
286 acres
116 acres
37 ft.
18 ft.
NA
0.3
1
1
1003502
358 acres
187 acres
72 ft.
17 ft.
NA
None
None
1
1003503
164 acres
48 acres
45 ft.
22 ft.
NA
0.16
1
1
1003504
descriptive
descriptive
descriptive
3:1
3:1
3:1
11:1
3:1
31:1
lakeshed includes lake area)
Standard Watershed to Lake Basin Ratio
(standard watershed includes lake areas)
Wetland Coverage
Aquatic Invasive Species
Public Drainage Ditches
Public Lake Accesses
Miles of Shoreline
Shoreline Development Index
Public Land to Private Land Ratio
Development Classification
Miles of Road
Municipalities in lakeshed
Forestry Practices
Feedlots
Sewage Management
Lake Management Plan
Lake Vegetation Survey/Plan
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10.2
10.5
4.9
None
None
None
None
None
None
None
1
None
2.6
10
2.1
1.1
2.9
1.1
0.068:1
0.068:1
0.068:1
Recreational Development
Recreational Development
Recreational Development
3.0
6.8
0.8
None
None
None
County Forest Management: http://www.co.crow-wing.mn.us/index.aspx?NID=261
None
None
None
Individual Subsurface Sewage Treatment Systems (Inspection and assessment required for all
permits and property transfers within the Shoreland Protection Zone)
Healthy Lakes & Rivers Partnership program, 1999 & 2005
None
None
None
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NA
descriptive
descriptive
descriptive
descriptive
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 land
resources in an organized fashion so
that the needs of the present and
future generations can be best
addressed. The basic purpose of
land use planning is to ensure that
each area of land will be used in a
manner that provides maximum
social benefits without degradation of
the land resource.
Changes in land use, and ultimately
land cover, impact the hydrology of a
lakeshed. Land cover is also directly
related to the lands ability to absorb
and store water rather than cause it
to flow overland (gathering nutrients
and sediment as it moves) towards
the lowest point, typically the lake.
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
Figure 19. The Portage Crooked Hanks lakesheds land cover
occurring in the lakeshed. Figure 19
(http://land.umn.edu).
depicts the land cover in Portage,
Crooked and Hanks Lakes’ lakesheds.
The University of Minnesota has online records of land cover statistics from years 1990 and 2000
(http://land.umn.edu). Although this data is 11 years old, it is the only data set available for comparing
a decade’s time. Table 10 describes Portage, Crooked, and Hanks 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 decrease in
agriculture cover (59%); however, in acreage, forest cover has increased the most (219 acres). The
urban and impervious areas did not change much from 1990-2000.
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Table 10. Portage Crooked Hanks Lake’s lakeshed land cover statistics and % change from 1990 to 2000
(http://land.umn.edu).
1990
2000
% Change
Land Cover
Acres
Percent
Acres
Percent
1990 to 2000
124
4.50
51
1.85 58.9% Decrease
Agriculture
274
9.94
283
10.27 3.3% Increase
Grass/Shrub/Wetland
1,119
40.60
1,338
48.55 19.6% Increase
Forest
1,112
40.35
956
34.69 14.0% Decrease
Water
122
4.43
125
4.54 2.5% Increase
Urban
Impervious Intensity %
0
1-10
11-25
26-40
41-60
61-80
81-100
Total Area
Total Impervious Area
(Percent Impervious Area
Excludes Water Area)
2,681
27
20
10
6
7
2
97.28
0.98
0.73
0.36
0.22
0.25
0.07
2,756
19
2,681
24
27
14
7
1
1
2,756
15
97.28
0.87
0.98
0.51
0.25
0.04
0.04
No Change
11.0% Decrease
35.0% Increase
40.0% Increase
16.7% Increase
85.7% Decrease
50% Decrease
21% Decrease
Demographics
Portage, Crooked, Sugar and Hanks Lakes are classified as
recreational development lakes. Recreational development lakes
usually have between 60 and 225 acres of water per mile of shoreline,
between 3 and 25 dwellings per mile of shoreline, and are more than
15 feet deep.
The Minnesota Department of Administration Geographic and
Demographic Analysis Division extrapolated future population in 5-year
increments out to 2035. Compared to Crow Wing County as a whole,
Bay Lake Township has a higher extrapolated growth projection (Figure
20).
Figure 20. Population
growth projection for
Bay Lake Township
and Crow Wing
County. (source:
http://www.demograph
y.state.mn.us/resourc
e.html?Id=19332)
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Portage Crooked Lakes Chain Lakeshed Water Quality Protection Strategy
Each lakeshed has a different makeup 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, 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 the Portage, Crooked, Sugar and Hanks lakesheds is made up of
private forested uplands (Table 11). This land can be the focus of development and protection efforts
in the lakeshed. A runoff coefficient for county land is not included in Table 11 because county land
consisted of primarily paved roads and right of way areas. The open water category (37.5%) is also
comparatively quite high. The lakeshed boundary closely follows the lakeshore in several areas.
Table 11. Land ownership, land use/land cover, estimated phosphorus loading, and ideas for protection and
restoration in the lakeshed (Sources: Crow Wing County parcel data, National Wetlands Inventory, and the 2006
National Land Cover Dataset).
37.5%
Private (58.5%)
Land Use (%)
Public (4%)
Developed
Agriculture
Forested
Uplands
Other
Wetlands
Open
Water
County
State
Federal
3.6%
4%
33%
9.2%
8.7%
37.5%
1.8%
2.2%
0%
0.45–1.5
0.26–0.9
0.09
0.09
0.09
0.09
44–148
28–97
81
22
5.4
Cropland
Focus of
development and
protection
efforts
Runoff
Coefficient
Lbs of
phosphorus/acre/
year
Estimated
Phosphorus
Loading
Acreage x runoff
coefficient
Description
Potential
Phase 3
Discussion
Items
Focused on
Shoreland
Shoreline
restoration
Restore
wetlands;
CRP
Open,
pasture,
grassland,
shrubland
Forest
stewardship
planning, 3rd
party
certification,
SFIA, local
woodland
cooperatives
Protected
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% disturbance 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
Watershed
Management
Comments
Protected
Disturbance
Type
(%)
(%)
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%.
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.
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.
> 75%
< 25%
25-60%
> 60%
n/a
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.
Portage, Crooked, and Hanks lakesheds are classified with having 44.7%, 39.0%, and 61.0% of the
watershed protected, respectively . The percent disturbed of each lakeshed is 14.4%, 7.9%, and
2.8%, respectively (Figure 21). All of these lakesheds should have a protection focus (Figure 22).
Goals for these areas should be to limit any increase in disturbed land use. In addition, Crooked Lake
is designated by DNR Fisheries as a high valued fishery lake because of its cisco population.
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 Nokay Lake, whether through
direct overland flow or through a creek or river.
Percent of the Watershed Protected
0%
75%
Crooked Portage
Lake (39.0%) (44.7%)
100%
Hanks
(61.0%)
Percent of the Watershed with Disturbed Land Cover
25%
0%
Hanks Lake Portage Lake
(14.4%)
(2.8%)
Crooked
Lake (7.9%)
100%
Figure 21. Portage, Crooked, and Hanks lakesheds’
percentage of watershed protected and disturbed.
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Figure 22. Upstream lakesheds that contribute water
to Portage, Crooked, and Hanks lakesheds. Colorcoded based on management focus (Table 12).
2011 Portage, Crooked, Sugar, Hanks Lakes
Portage, Status of the Fishery (as of 06/12/2006)
The walleye catch rate was average in Portage Lake when compared to similar lakes (1.5/gill net).
Average size was 24.0" and 5.7 lbs. All of the fish were over 12" and at least 13 years old.
The northern pike catch rate was high, but dominated by smaller fish. Average size was 18.3" and
1.4 lbs. Only 6% of the fish were 24" or larger.
Largemouth bass were captured at the rate of 54.0/hr run-time during spring electrofishing.
Average length was 12.6" and 63% of these fish were 12" or larger.
The black crappie catch rate was average in gill nets (1.0/gill net). Average length was 11.9" and
all of the fish were 8" or larger.
The bluegill catch rate was the lowest to date at 7.3/trap net. Average length was 6.2" and 22%
were 7" or larger.
Other fish species captured included black bullhead, bowfin, brown bullhead, hybrid sunfish,
pumpkinseed, rock bass, tullibee, yellow bullhead, and yellow perch.
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=18005000
Crooked, Status of the Fishery (as of 06/05/2006)
The walleye catch rate was below average in Crooked Lake when compared to similar lakes
(0.4/gill net). Average size was 23.2" and 4.4 lbs. All of the fish were over 12".
The northern pike catch rate was above average (15.6/gill net). Fish were small averaging only
18.6" and 1.7 lbs., with 13% measuring 24" or larger.
Largemouth bass were captured at the rate of 96.0/hr run-time during spring electrofishing.
Average length was 11.1" and 36% were 12" or larger.
The black crappie catch rate was below average in gill nets (0.4/gill net), with an average length of
7.6". The trap net catch rate of 1.8 was average. These fish had an average length of 8.7". When
both net types were combined, 55% of the fish were 8" or larger.
Even though the bluegill catch rate was the lowest to date, it was still above average (24.7/trap
net). Average length was 6.2" and 24% were 7" or larger.
Tullibees were caught in high numbers for this type of lake (9.4/gill net). Average length was 11.8".
Other fish species captured included black bullhead, bowfin, brown bullhead, hybrid sunfish,
pumpkinseed, rock bass, yellow bullhead, and yellow perch
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=18004100
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Hanks, Status of the Fishery (as of 06/05/2006)
The walleye catch rate was average in Hanks Lake when compared to similar lakes (1.5/gill net).
Average size was 24.2" and 5.2 lbs. All of the fish were over 12".
The northern pike catch rate was above average (21.2/gill net). Fish were small averaging only
19.3" and 1.7 lbs. Only 9% of the fish were 24" or larger.
Largemouth bass were captured in high numbers while spring electrofishing (140/hr run-time).
Average length was 11.3" and 39% were 12" or larger.
The black crappie catch rate was average in gill nets (1.8/gill net), with an average length of 10.9".
The trap net catch rate of 0.2 was below average. These fish had an average length of 10.0". All of
the fish were 8" or larger.
The bluegill catch rate was the lowest to date at 8.9/trap net. Average length was 6.5" and 30%
were 7" or larger.
Tullibees were caught in very high numbers for this type of lake (13.8/gill net). Average length of
these fish was 11.6".
Other fish species captured included black bullhead, bowfin, brown bullhead, hybrid sunfish,
pumpkinseed, rock bass, yellow bullhead, and yellow perch.
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=18004400
Key Findings / Recommendations
Monitoring Recommendations
Transparency monitoring at the primary site in each lake (see Table 3, page 3) should be
continued annually. It is important to continue transparency monitoring weekly or at least
bimonthly every year to enable year-to-year comparisons and trend analyses. Phosphorus and
chlorophyll a data should be collected, as the budget allows, to track future water quality trends.
Overall Conclusions
Portage, Crooked, Sugar Bay, and Hanks Lakes are exceptional water resources. Overall, they
are in excellent shape for water quality and fairly good shape for lakeshed protection. These lakes
are on the border between oligotrophic/mesotrophic lake (TSI=40-41) with improving trends in
transparency. Four percent (4%) of the combined lakesheds are in public ownership. Portage,
Crooked, and Hanks lakesheds are classified with having 44.7%, 39.0%, and 61.0% of the
lakeshed protected, respectively. The percent of disturbed land in each lakeshed is 14.4%, 7.9%,
and 2.8%, respectively (Figure 21). Hanks Lakeshed is the best protected and least disturbed. All
of these lakesheds should have a protection focus (Figure 22).
Crooked Lake is designated by the DNR as a Cisco (Tullibee) refuge lake. Ciscos require good
water quality and cold deep water to survive and are excellent forage for game fish. Ciscos are
considered water quality indicators, because the loss of ciscos can be an indicator of lake
eutrophication.
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Portage, Crooked and Hanks lakes are at an advantage in that only one other lakeshed drains into
it (Figure 22). This means that the land practices around the lake are the main impact to the lake’s
water quality.
Priority Impacts to the Lake
The priority impact to these lakes is the surrounding development and any future second tier
development. The majority of the lakes are developed in the first tier, and some small areas on
each lake are developed in the second tier. Second tier development significantly changes the
drainage and runoff to the lake. There was not much change in urban or impervious surface from
1990-2000 (Table 10). The population in Bay Lake Township is projected to grow by 15% in the
next 10 years (Figure 20).
Best Management Practices Recommendations
The management focus for Portage, Crooked and Hanks Lakes should be to protect the current
water quality and better protect the lakeshed. Efforts should be focused on managing and/or
decreasing the impact caused by current and 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.
County-wide Recommendation
In order to better manage the impact of septic systems on lake water quality, it is recommended
that the county implement a lake-wide septic inspection program. In a program such as this, the
county would focus on one to three lakes a year, pull septic system records on those lakes, and
require old systems to be inspected. This program can rotate through the county doing a few lakes
each year.
Organizational contacts and reference sites
Portage, Crooked, Sugar, and
Hanks Lake Association (PCLIA)
DNR Fisheries Office
Regional Minnesota Pollution
Control Agency Office
Crow Wing Soil and Water
Conservation District
Crow Wing County Environmental
Services Department
http://www.minnesotawaters.org/group/pclia/welcome
1601 Minnesota Drive, Brainerd, MN 56401
218-828-2550
[email protected]
7678 College Road, Suite 105, Baxter, MN 56425
218-828-2492, 800-657-3864
http://www.pca.state.mn.us/pyri3df
Crow Wing County Land Services Building
322 Laurel St. Suite 13, Brainerd, MN 56401
218-828-6197
http://www.co.crow-wing.mn.us/swcd/
Crow Wing County Land Services Building
322 Laurel St. Suite 14, Brainerd, MN 56401
218-824-1125
http://www.co.crow-wing.mn.us/index.aspx?nid=211
Funding
This project was funded in part by the Board of Water & Soil Resources and the Initiative
Foundation, a regional foundation.
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