Memorandum
To:
Valley Branch Watershed District (VBWD) Board of Managers
From:
Meg Rattei, Senior Biologist
Subject: VBWD June 2015 Point-Intercept Plant Surveys
Date:
October 1, 2015
Project: 23/82-0405
c:
John Hanson, Ray Marshall, Ray Roemmich, Melissa Imse
This memorandum summarizes methods and results of the June 2015 point-intercept plant surveys at
Long Lake, Lake DeMontreville, Lake Olson, Lake Jane, Eagle Point Lake, Lake Elmo, Horseshoe Lake, Lake
Edith, McDonald Lake, and Sunfish Lake. All tables and figures follow the discussion.
Requested Manager Actions
1.
Authorize the release of this memorandum to the following:
A. Maynard Kelsey of McDonald Lake
B.
Brian Buchmayer of Friends of Long Lake and the VBWD Lake Citizen Advisory Committee
C. Justin Bloyer of the Lake Jane Association and council member, City of Lake Elmo
D. Roger Johnson of the Lake DeMontreville/Olson Association and the VBWD Citizen Advisory
Committee
E.
Wendy Griffin of the Lake Elmo Association
F.
Jeff Berg of the Lake Elmo Association and the VBWD Citizen Advisory Committee
G. Dale Dorschner of the Lake Elmo Association
H. Keegan Lund, Chip Welling, and any other interested staff of the Minnesota Department of
Natural Resources (MDNR).
2.
Authorize the release of the eight reports submitted to Washington County to fulfill the VBWD
Aquatic Invasive Species (AIS) Grant contractual obligation to Keegan Lund, Chip Welling, and any
other interested MDNR staff.
3.
Direct Barr to request a meeting with MDNR to discuss the results of the 2015 herbicide treatments
for Long Lake, Lake DeMontreville, Lake Olson, and Lake Jane and ask for suggestions moving
forward. The meeting could also include discussion of 2015 diver harvesting of Eurasian watermilfoil
(EWM) in Lake Elmo and MDNR suggestions for moving forward.
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5.
VBWD Managers
Meg Rattei
VBWD June 2015 Point-Intercept Macrophyte Surveys
October 1, 2015
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23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Initiate a VBWD grant program to fund 50% of the cost (up to a maximum total amount set by the
Managers) for herbicide treatments sponsored by lake associations to reduce aquatic invasive plants
such as EWM in VBWD lakes. A VBWD grant program would provide the financial assistance lake
associations need to manage aquatic invasive species (AIS), while reducing administrative costs. This
would make the program less expensive than procuring funds from other programs such as the
Washington County AIS grant program. In 2015, VBWD procured Washington County AIS grant funds
and used the funds to reimburse lake associations for about half of the cost of herbicide treatment to
manage EWM in VBWD lakes. The administrative costs required by the grant program exceeded the
amount of the grant award. These efforts included preparing a proposal, an interview, preparing a
contract, completing eight different reports, and providing presentations at two meetings. Initiating a
VBWD grant program would provide the same level of funding to lake associations, but at a lower
cost to the District.
6.
Authorize technical support to lake associations that want to complete herbicide treatment to
manage EWM in 2016. Barr anticipates that support will be needed for Friends of Long Lake, Lake
DeMontreville/Olson Association, and the Lake Jane Association. Technical support would include:

Two point-intercept plant surveys, one in spring before treatment and one in June after
treatment. Both are permit requirements.
7.

Permitting.

Treatment.

Reporting required by the MDNR treatment permit.
Authorize technical support to Friends of Long Lake to update the Long Lake Lake Vegetation
Management Plan (LVMP) prior to the 2016 herbicide treatment season. The Long Lake LVMP will
expire on April 15, 2016.
2014 Sample Methods
Matt Berg of Endangered Resource Services, LLC conducted pointintercept plant surveys in 10 VBWD lakes from June 21 through
June 24, 2015. He located equally spaced preset points in the field
with GPS and took measurements at each point. His measurements
included the following:
1.
Individual species present
2.
Overall density of plants, as measured by rake method
3.
Density of individual species, as measured by rake method
Endangered Resource Services used a rake
(pictured above) to collect plants for the
plant surveys. Rake fullness is a measure
of plant density.
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VBWD Managers
Meg Rattei
VBWD June 2015 Point-Intercept Macrophyte Surveys
October 1, 2015
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John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
4.
Water depth
5.
Dominant sediment type
Results
A discussion of survey results for the 10 individual lakes follows.
VBWD provided technical assistance for herbicide management of
EWM in Long Lake, Lake DeMontreville, Lake Olson, and Lake
Jane in 2015. A discussion of the results of these management
efforts is also included the following paragraphs.
Long Lake—Long Lake has been treated with herbicide almost
annually since 2011 to reduce the extent of EWM in the lake. In
2015, 5.5 acres of EWM were observed in the lake during the May
pre-treatment plant survey; all EWM observed in the lake was
treated with 2,4-D in May (Figures 1 and 2). The average 2,4-D
concentration measured in the lake 3 days after treatment was
lethal to EWM (Figure 3).
EWM was only observed at two locations in
Long Lake during 2015. Pictured above is
the single barely surviving EWM plant
The Long Lake treatment goal of reducing EWM by at least half
collected in 19 feet of water.
was met. EWM area was reduced by 93 percent (Figures 4 and 5) and frequency was reduced by 91
percent between May and June of 2015 (Figure 6). In addition, EWM density was reduced (Figure 7). In
June 2010, prior to the start of herbicide treatment, EWM extent was 52 acres, which was 97 percent of
the plant growth area of the lake (Table 3). After treatment in 2015, EWM extent was 0.4 acres—0.73
percent of the plant growth area of the lake (Table 3). Since herbicide treatment began in 2011, the
frequency of EWM occurrence has been reduced from 92 percent to 1 percent (Figure 6).
No significant changes in the frequency of individual native plant species were observed in Long Lake
between May and June of 2015, verifying that the herbicide treatment had no impact on the frequency of
1
individual native plant species . Common waterweed significantly increased in frequency between June of
2014 and June of 2015, a positive change for the Long Lake plant community (Figure 8).
Reduction of EWM in Long Lake during 2015 improved the overall frequency of native plants in the lake,
but had no impact on the number of native species. The frequency of occurrence of natives increased
1
Margaret Rattei, letter to June Mathiowetz regarding VBWD AIS Grant Project: Deliverable 7 – Report on
Native Plant and Eurasian Watermilfoil (EWM) Presence in Post-Treatment Plant Surveys, 8 Sept. 2015. TS.
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Meg Rattei
VBWD June 2015 Point-Intercept Macrophyte Surveys
October 1, 2015
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John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
from 33 percent in June of 2014 to 47 percent in June of 2015, while the number of native species (10)
remained the same (Table 8).
Since treatment began in 2011, the quality of the Long Lake plant
community, measured by the Floristic Quality Index (FQI), has
improved. FQI considers both the quality of the individual native
species in the lake and the number of species collected on the
rake. The 2010 pre-treatment FQI value was 14.1, compared with
the 2011 post-treatment value of 15.7 (Figure 9). All FQI values
since 2011 have been greater than 14.1, including the 2015 value
of 16.8 (Figure 9). This indicates that EWM reduction has improved
the quality of the lake’s plant community.
The diversity of the Long Lake plant community approximately
doubled after the first herbicide treatment in 2011. This is
Reduction of EWM in 2015 improved the
reflected by Simpson Diversity Index values, which indicate the
frequency of native plants, including Chara,
probability that two individual plants randomly selected from a
pictured above. Chara increased in frequency
lake will belong to different species. The 2010 pre-treatment
from 20 to 26 percent of sample locations.
Simpson Diversity Index value was 0.4, compared with values of
0.77 to 0.85 from 2011 through 2015 (Figure 10). This indicates that reduction of EWM has improved plant
diversity; i.e., the probability that two individual plants randomly selected from Long Lake will belong to
different species has increased from 40 percent to 77–85 percent.
Curly-leaf pondweed (CLP), an invasive species, is present in Long Lake but not problematic. In 2015, CLP
was found in 6 percent of the sample locations in the plant growth area of the lake, the same frequency
observed in 2010 (Figure 11).
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VBWD Managers
Meg Rattei
VBWD June 2015 Point-Intercept Macrophyte Surveys
October 1, 2015
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23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Lake DeMontreville—In 2015, the MDNR did not permit herbicide treatment of all EWM-infested areas
within Lake DeMontreville. The total permitted treatment area of 14 acres was only 24 percent of the 58
acres infested (Figures 2 and 12). Because the treatment area was small and shallow, the quantity of
herbicide allowed for the treatment was insufficient to attain a
lethal, lake-wide 2,4-D concentration and exposure time. Results of
research conducted by the Wisconsin Department of Natural
Resources indicate the average 2,4-D concentration of 0.185 parts
per million (ppm) measured 3 days after treatment (Figure 3) would
result in seasonal control of EWM if sustained for 7 days, but would
not attain long-term EWM control.
2
Although the EWM area treated in 2015 was only 24 percent of the
infested area, the Lake DeMontreville goal of reducing EWM by at
least half was met. Between May and June of 2015, the EWM area
was reduced by 64 percent (Figures 4 and 13) and frequency was
reduced by 51 percent (Figure 14). In addition, EWM density was
reduced (Figure 15). The 2015 treatment mitigated the EWM
increase that occurred between June of 2014 and spring of 2015
and provided some reduction in EWM area, frequency, and density
EWM was severely knocked back, but a
few plants, especially along deep-water
(Figures 13 through 15).
margins, continue to survive. Pictured
Significant changes in six native species were observed in Lake
found mid-lake in the central basin of
above is a deep water EWM fragment
DeMontreville between May and June of 2015 (a significant
Lake DeMontreville.
decrease in northern watermilfoil and significant increases in five other species). The herbicide treatment
could have caused the decline in northern watermilfoil frequency. However, rapid increases and decreases
are common for northern watermilfoil. An untreated VBWD lake, Lake Edith, observed a rapid increase in
northern watermilfoil in 2014 and a rapid decrease in 2015 (Figure 40). Hence, the significant decline in
northern watermilfoil in Lake DeMontreville during 2015 could have been due to natural fluctuations.
Nonetheless, the significant increase in five native species resulted in a net increase in native plant
frequency following the 2015 herbicide treatment.
2
1
Heath, Eddie, Tim Hoyman, Michelle Nault, and John Skogerboe. 2014. Field Research of Early-Season
Whole-Lake Herbicide Strategies for Control of Hybrid EWM. Presentation at UMISC – October 22, 2014 in
Duluth, Minnesota.
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VBWD Managers
Meg Rattei
VBWD June 2015 Point-Intercept Macrophyte Surveys
October 1, 2015
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John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
During a one-year period (June of 2014 to June of 2015)
significant changes were observed in three native plant
species in Lake DeMontreville—again, a significant
decrease in northern watermilfoil and significant increases
in filamentous algae and southern naiad (Figure 16).
1
Reduction of EWM in Lake DeMontreville during 2015
improved the frequency of native plants in the lake, but
had no impact on the number of native species. The
frequency of occurrence of native plants increased from 89
percent in June of 2014 to 94 percent in June of 2015,
while the number of native species (19) remained the
Pictured above, yellow iris plants shortly before they
were removed from Lake DeMontreville in June of
same (Table 9).
2014. In 2015, yellow iris plants were common on the
Since treatment began in 2014, the quality of the Lake
mowing around the plants and maintaining them
DeMontreville plant community, measured by the FQI,
southern shoreline of the lake, with residents
along their shoreline.
has improved. FQI considers both the quality of the individual native species in the lake and the number
of species collected on the rake. The 2012 and 2013 pre-treatment FQI values ranged from 25.0 to 26.2,
compared with post-treatment values of 26.9 during 2014 and 2015 (Figure 17). This indicates that EWM
reduction improved the quality of the lake’s plant community.
The diversity of the Lake DeMontreville plant community remained stable after treatment. This is reflected
by Simpson Diversity Index values, which indicate the probability that two individual plants randomly
selected from a lake will belong to different species. The 2014 and 2015 post-treatment Simpson Diversity
Index values of 0.90 were within the range of 2012 and 2013 pre-treatment values (0.89 to 0.90) (Figure
18). This suggests that EWM treatment had no impact on native plant diversity; i.e., the probability that
two individual plants randomly selected from Lake DeMontreville will belong to different species has
remained at about 90 percent.
Yellow iris, an invasive species, was common on the southern shorelines in 2015. It appears that residents
are unaware it is a non-native, invasive plant—mowing around and maintaining the plants along their
shorelines. In June of 2014, VBWD directed Barr staff to remove yellow iris plants growing near the boat
(30 plants). We recommend that residents remove the yellow iris plants from their shoreline to prevent the
spread and proliferation of this invasive species.
CLP frequency in Lake DeMontreville has fluctuated widely during the past few years (49-percent
frequency in 2012, 42 percent in 2013, 10 percent in 2014, and 31 percent in 2015) (Figure 19). The 2015
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Meg Rattei
VBWD June 2015 Point-Intercept Macrophyte Surveys
October 1, 2015
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John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
frequency of 31 percent was within the 10 to 49 percent range
observed from 2012 through 2014 (Figure 19). CLP density was
low in 2015 and not problematic.
Lake Olson—In 2015, the MDNR did not permit herbicide
treatment of all EWM-infested areas within Lake Olson. The total
permitted treatment area of 7 acres was only 22 percent of the 32
EWM-infested acres (Figures 2 and 20). Because the treatment
area was small and shallow, the quantity of herbicide allowed for
treatment was insufficient to attain a lethal, lake-wide 2,4-D
concentration and exposure time. Results of research conducted
by the Wisconsin Department of Natural Resources indicate the
average 2,4-D concentration of 0.156 ppm measured 3 days after
treatment (Figure 3) would result in seasonal control of EWM if
sustained for 7 days, but would not attain long-term control.
2
The project goal of a 50% reduction in EWM was not attained.
EWM area was reduced by 11 percent (Figures 4 and 21) and
density was also reduced (Figure 23); however, frequency
increased by 4 percent (Figure 22) between May and June of
2015. The 2015 treatment partially mitigated the EWM increase
EWM was burned and knocked back by the
herbicide treatment, but it appeared the
majority of the plants (not necessarily the
stems) survived. Pictured above is a
surviving EWM plant and pictured below is
the typical density of surviving EWM in
Lake Olson.
that occurred from June of 2014 to spring of 2015 and provided
some reduction in EWM area and density (Figures 21 and 23).
Although the EWM management goal was not attained, lake
residents have expressed satisfaction in the EWM reduction after
the 2015 herbicide treatment.
The 2015 EWM reduction goal was not met because only
22 percent of the EWM area was treated (as restricted by the MDNR). The treatment area was a single
location at the south end of the lake near the outlet (Figure 20). Lake flow is toward the outlet, reducing
the likelihood of herbicide mixing to the north and central areas of the lake. The average 2,4-D
concentration measured in the lake 3 days after treatment was less than one-third of the lethal dose
(Figure 3). The area with the densest EWM was treated, but the concentration of herbicide was too low.
Hence, the June 2015 EWM area was 17 percent greater than the June 2014 EWM area (Figure 21).
Significant changes in five native plant species were observed between May and June of 2015, but none
were due to the herbicide treatment. There was a significant decrease in filamentous algae (algae are not
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Meg Rattei
VBWD June 2015 Point-Intercept Macrophyte Surveys
October 1, 2015
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John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
impacted by 2,4-D) and significant increases in four native plant species. The result was a net increase in
native plant frequency after the herbicide treatment.
2
Between June of 2014 and June of 2015, significant changes in seven native plant species were observed,
but none were due to the herbicide treatment. The changes included significant decreases in coontail,
filamentous algae, water stargrass, northern watermilfoil, and small pondweed (Figure 24). Significant
increases in fern pondweed and muskgrasses also occurred (Figure 24). Of the declining native species,
coontail and northern watermilfoil are the only species potentially impacted by 2,4-D; however, neither
species declined significantly between May and June of 2015. This indicates that declines between June of
2014 and June of 2015 were not caused by the herbicide treatment. Expanding EWM and subsequent
displacement of natives during 2014 could have been a factor in the declines. EWM expanded from 28
acres in June of 2014 to 32 acres by May of 2015 (Figure 21).
Although both native plant frequency and number of species declined in 2015, the declines are not likely
due to the herbicide treatment. The frequency of native species in Lake Olson decreased from 91 percent
in June of 2014 to 82 percent in June of 2015. The number of native species decreased from 20 in June of
2014 to 19 in June of 2015 (Table 10). Based on historic natural variation of plants affected and locations
of the changes, the native plant changes do not appear to be caused by the herbicide treatment.
1
Since treatment began in 2014, the quality of the Lake Olson plant community, measured by the FQI, has
improved. FQI considers both the quality of the individual native species in the lake and the number of
species collected on the rake. The 2012 and 2013 pre-treatment FQI values ranged from 25.2 to 25.9,
compared with post-treatment values in 2014 and 2015 of 26.6 to 28.0 (Figure 25).
The diversity of the Lake Olson plant community remained stable after treatment. This is reflected by
Simpson Diversity Index values, which indicate the probability that two individual plants randomly
selected from a lake will belong to different species. The 2012 and 2013 pre-treatment Simpson Diversity
Index values ranged from 0.91 to 0.92. The post-treatment value from 2014 through 2015 is 0.90 (Figure
26); i.e., the probability that two plants selected at random from Lake Olson will belong to different
species has stayed in the range of 90–92 percent.
CLP was present at a few locations, but was not problematic in 2015. CLP was found at 5 percent of
sample locations in 2015, compared with 3 percent in 2014 (Figure 27).
Lake Jane—In 2015, the MDNR did not permit herbicide treatment of all EWM-infested areas within Lake
Jane. The total permitted treatment area of 7.9 acres was only 18 percent of the 44 EWM-infested acres
(Figures 2 and 28). Because the treatment area was small and shallow, the quantity of herbicide allowed
for the treatment was insufficient to attain a lethal, lake-wide 2,4-D concentration and exposure time.
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VBWD Managers
Meg Rattei
VBWD June 2015 Point-Intercept Macrophyte Surveys
October 1, 2015
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John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Results of research conducted by the Wisconsin
Department of Natural Resources indicate the average
2,4-D concentration of 0.081 ppm measured 3 days
after treatment (Figure 3) may have no effect on EWM.
2
The project goal of reducing EWM by at least half was
not attained in Lake Jane. Between May and June of
2015 EWM area was reduced by 30 percent (Figures 4
and 29) and frequency was reduced by 28 percent
(Figure 30); EWM density was also reduced (Figure 31).
The 2015 treatment partially mitigated the EWM
increase that occurred from June of 2014 to spring of
EWM in Lake Jane was seriously burned by the
2015 and provided some reduction in EWM area,
herbicide treatment, but many plants survived. Many
frequency, and density (Figures 29 through 31).
small fragments of EWM were re-growing from axils.
Pictured above, surviving EWM on Lake Jane.
Although the EWM reduction goal was not attained,
lake residents have expressed satisfaction in the EWM
reduction occurring after the 2015 herbicide treatment.
The 2015 herbicide treatment did not attain the EWM
reduction goal because only 18 percent of the EWM
area was treated (as restricted by the MDNR). The
average 2,4-D concentration measured in the lake
3 days after treatment was less than 20 percent of the
EWM lethal dose (Figure 3). While the area with the
densest EWM was treated, the concentration of
herbicide was too low (Figure 29). Hence, the June
Pictured above, typical Lake Jane EWM that was
2015 EWM area was 29 percent greater than the June
damaged but not killed.
2014 EWM area (Figure 29).
Significant changes in seven native plant species were observed between May and June of 2015, but none
of the changes were due to the herbicide treatment. The changes included a significant decrease in water
stargrass, which is not impacted by 2,4-D. Significant increases in six native plant species resulted in a net
increase after the herbicide treatment.
1
Between June of 2014 and June of 2015 significant changes were observed in three native plant species,
but none of the changes were due to the herbicide treatment. The changes included an increase in
filamentous algae and decreases in water stargrass (not impacted by 2,4-D) and northern watermilfoil
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Meg Rattei
VBWD June 2015 Point-Intercept Macrophyte Surveys
October 1, 2015
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John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
(Figure 32). Northern watermilfoil did not decline significantly between May and June of 2015, indicating
its decline between June of 2014 and June of 2015 was not caused by the herbicide treatment. Expanding
EWM and subsequent displacement of natives during 2014 could have been a factor in the decline. EWM
expanded from 24 acres in June of 2014 to 44 acres in May of 2015 (Figure 29).
Although both native plant frequency and number of species declined in 2015, the declines are not likely
due to the herbicide treatment. The frequency of native species in Lake Jane decreased from 99 percent in
June of 2014 to 96 percent in June of 2015. The number of native species decreased from 28 in June of
2014 to 24 in June of 2015 (Table 11). Based on historic natural variation and plants affected, the native
plant changes do not appear to be caused by the herbicide treatment.
1
The quality of the Lake Jane plant community, measured by the FQI, remained stable after the 2015
herbicide treatment. FQI considers both the quality of the individual native species in the lake and the
number of species collected on the rake. The 2012 through 2014 pre-treatment FQI values ranged from
31.0 to 32.7, compared with the 2015 post-treatment value of 31.4 (Figure 33).
After the 2015 treatment, the diversity of the Lake Jane plant community did not change. This is reflected
by Simpson Diversity Index values, which indicate the probability that two individual plants randomly
selected from a lake will belong to different species. The 2012 through 2014 pre-treatment Simpson
Diversity Index values ranged from 0.91 to 0.92, compared with a 2015 post-treatment value of 0.92
(Figure 34); i.e., the probability that two plants selected at random from Lake Jane will belong to different
species has stayed in the range of 91–92 percent.
CLP was present in 2015, but not problematic; the plant was observed in 11 percent of sample locations
within the plant growth area of the lake, which was within the 8- to 16-percent frequency documented
from 2012 through 2014 (Figure 35).
Eagle Point Lake—Problematic growths of the invasive CLP were observed in Eagle Point Lake from 2012
through 2015 (Figure 36). However, CLP was stable in 2015 with the density and distribution similar to
2014 levels.
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Meg Rattei
VBWD June 2015 Point-Intercept Macrophyte Surveys
October 1, 2015
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Two additional invasive species were observed in Eagle Point Lake
in 2015; however, both were stable and not problematic. Reed
canary grass was abundant along the lakeshore and in surrounding
wetland areas—a distribution similar to 2014. The distribution of
narrow-leaved cattail was also similar to distributions from 2012
through 2014. Narrow-leaved cattail was observed in 29 percent of
sample points in 2015 (Table 2) compared to 24 to 30 percent from
3
2012 through 2014 .
The greatest change in the Eagle Point Lake plant community in
2015 was a significant increase in the extent of filamentous algae.
Problematic growths of CLP (pictured
The frequency of occurrence of filamentous algae increased from
above) were observed in Eagle Point
4 percent of sample locations in 2014 to 55 percent in 2015
Lake from 2012 through 2015.
(Figure 37). The increased extent of filamentous algae and
associated shading reduced the growth of other plants, likely
causing the significant 2015 declines in frequency observed for
common waterweed, small pondweed, small duckweed, and river
bulrush (Figure 37). In addition, the increased algae reduced the
maximum depth at which plants were growing by over half—from
8.5 feet in 2014 to 4 feet in 2015.
Despite the increased extent of algae and significant declines in
frequency of four native plant species in 2015, the quality of the
plant community, measured by FQI, was stable. FQI considers
The frequency of occurrence of
both the quality of the individual native species in the lake and
filamentous algae in Eagle Point Lake
the number of species collected on the rake. The 2015 FQI value
(pictured above) increased from
of 19.2 was within the 2012 through 2014 range of 18.7 to 22.6
(Figure 38).
4 percent of sample locations in 2014 to
55 percent in 2015.
Plant diversity was also stable in 2015. This is reflected by Simpson Diversity Index values, which indicate
the probability that two individual plants randomly selected from a lake will belong to different species.
The 2015 value of 0.84 was within the 2012 through 2014 range of 0.84 through 0.88 (Figure 39); i.e., the
3
Margaret R. Rattei to Valley Branch Watershed District (VBWD) Board of Managers, October 3, 2014.
VBWD June 2015 Point-Intercept Macrophyte Surveys.
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Meg Rattei
VBWD June 2015 Point-Intercept Macrophyte Surveys
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John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
probability that two individual plants selected randomly from Eagle Point Lake will belong to different
species has stayed in the range of 84 to 88 percent.
Lake Edith—Carp were observed throughout the lake in 2015,
explaining some of the limitations in the Lake Edith plant community.
Carp can severely reduce submersed aquatic vegetation through
direct uprooting of vegetation or herbivory (eating the vegetation).
4
Aquatic plant growth in the lake is also limited by the lake’s poor
growing substrate for plants (marly clay and thin muck over sand).
This poor substrate protects the lake from problematic growth by
invasive species.
Three invasive species were present in Lake Edith in 2015, but none
were problematic. All three species were observed at a low
The native plant community in Lake
frequency, similar to previous years. Curly-leaf pondweed was
Edith remained stable in 2015 including
observed at a frequency of 4 percent annually from 2013 through
2015 (Figures 40 and 43). Reed canary grass was visually observed in
the lake in 2013 and observed at a frequency of 1 percent during
the continued presence of Illinois
pondweed at the south end of the lake
(pictured above) and hardstem bulrush
at the lake’s outlet (pictured below).
2014 and 2015 (Figure 40). Hybrid cattail was observed at a
frequency of 3 percent in 2013, 1 percent in 2014, and 4 percent in
2015 (Figure 40). Although the frequency of hybrid cattail has
fluctuated since 2013, the differences are not significant.
The native plant community has remained relatively stable from 2013
through 2015. Northern watermilfoil significantly increased in
frequency in 2014 and significantly decreased in frequency in 2015;
its 2015 frequency was relatively similar to its 2013 frequency (Figure
40). Rapid increases and decreases are common for northern
watermilfoil.
There were two positive changes to the plant community in 2015:

A significant increase in small pondweed—observed at a frequency of 1 percent in 2013, not
observed in 2014, and observed at a frequency of 11 percent in 2015 (Figure 40).
4
Bajer, P.G., G. Sullivan, P.W. Sorenson. 2009. Effects of Rapidly Increasing Population of Common Carp on
Vegetative Cover and Waterfowl in a Recently Restored Midwestern Shallow Lake. Hydrobiologia. Doi:
10.1007/s 10750-009-9844-3.
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VBWD Managers
Meg Rattei
VBWD June 2015 Point-Intercept Macrophyte Surveys
October 1, 2015
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Presence of water stargrass—observed for the first time
in 2015 (Figure 40).
The quality of the lake’s plant community, measured by FQI, and
its diversity, measured by Simpson’s Diversity Index, both
improved in 2015. FQI considers both the quality of the individual
native species in the lake and the number of species collected on
the rake. The 2015 FQI value of 22.1 was higher than values of
19.1 through 21.8 observed in 2013 and 2014 (Figure 41). The
EWM was problematic in Lake Elmo
during 2015. Canopied EWM was
2015 Simpson’s Diversity Index value of 0.92 was higher than
observed in 7 to 10 feet of water along
values of 0.88 and 0.89 observed in 2013 and 2014 (Figure 42);
the north western shoreline (pictured
i.e., the probability that two individual plants randomly selected
from the lake will belong to different species increased from 88
and 89 percent in 2013 and 2014 to 92 percent in 2015.
above) and canopied EWM was mixed
with floating-leaf pondweed in 3 to 4
feet of water on the western shoreline
(pictured immediately below).
Lake Elmo— Problematic levels of EWM were observed in Lake
Elmo from 2012 through 2015. In 2015, as in previous years, EWM
was the dominant plant in the north and south bays; overall, the
plant increased in total area, frequency of occurrence, and the
percent of the plant growth area occupied. From 2014 to 2015,
EWM area increased from 51 acres to 68 acres (Table 7),
frequency increased from 34 percent to 45 percent (Figure 44),
and percent of the lake’s plant growth area occupied increased
from 45 percent to 59 percent (Table 7). As shown in Figure 45,
dense canopied beds of EWM (beds that have reached the lake
surface) were prevalent in 2015; however, despite the increased
extent and frequency, EWM levels were within the 2012 through
2013 range (Table 7).
Because Lake Elmo is classified as a “natural environment” lake,
the use of herbicides is not allowed without obtaining a variance
to the Minnesota rule. The MDNR did not provide this variance. In
September, the Lake Elmo Lake Association hired divers to hand
remove EWM from an area that was less than an acre. The EWM
hand removal area was about 1 percent of the 68 acres infested
EWM density in canopied beds was
with EWM (Table 7).
typically the maximum rake fullness of 4.
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Although four invasive species are present in Lake Elmo; EWM is the only problematic invasive species. A
single floating CLP plant was observed in Lake Elmo during the 2015 plant survey. CLP frequency in Lake
Elmo was 0 percent from 2013 through 2015 because it was not collected on the rake during plant surveys
(Figure 46). The frequency of reed canary grass declined steadily from 2012 through 2014 and was not
observed in Lake Elmo during 2015 (Figure 47). Narrow-leaved cattails were present but not problematic.
Their 2015 frequency of 17 percent was within the 2012 through 2014 range of 15 to 17 percent (Figure
47).
The Lake Elmo native plant community was stable in 2015 and no significant changes in native plant
frequency were observed (Figure 47).
In addition, 2015 plant community quality (measured by FQI) and diversity (measured by Simpson’s
Diversity Index) were stable. FQI considers both the quality of the individual native species in the lake and
the number of species collected on the rake. The 2015 FQI value of 23.5 was within the 20.4 to 26.1 range
observed from 2012 through 2014 (Figure 48). The 2015 Simpson’s Diversity Index value of 0.88 was
within the 0.88 to 0.91 range of values observed from 2012 through 2014 (Figure 49); i.e., the probability
that two individual plants randomly selected from the lake will belong to different species has remained in
the range of 88 to 91 percent.
Horseshoe Lake—EWM was the dominant plant in Horseshoe Lake in 2015 and was canopied (reached
the lake’s surface) in the majority of the littoral zone (plant growth area). EWM frequency in Horseshoe
Lake is higher than any other VBWD lake (Table 2) and has significantly increased: from 10 percent in
2013, to 40 percent in 2015, to 62 percent in 2015 (Figure 50). There has also been an annual increase in
density: from a rake fullness of 1.4 in 2013, to 2.4 in 2014, to 2.6 in 2015.
EWM was the only problematic invasive species in Horseshoe Lake during 2015. CLP, reed canary grass,
and narrow-leaved cattail frequency have fluctuated at low levels from 2013 through 2015. The 2015 CLP
frequency of 6 percent was within the 4- to 7-percent frequency observed from 2013 through 2014
(Figure 51), and the 2015 reed canary grass frequency of 6 percent was within the 6- to 7-percent
frequency observed during 2013 and 2014 (Figure 51). The 2015 narrow-leaf cattail frequency of 12
percent was only slightly higher than the 8- to 11-percent frequency observed from 2013 through 2014
(Figure 52).
The Horseshoe Lake native plant community was stable in 2015 and no significant changes in native plant
frequency were observed (Figure 52).
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Pictured above, panorama of canopied EWM in the northwest bay of Horseshoe Lake, just west of the golf course.
The 2015 plant community quality, measured by FQI, was stable. FQI considers both the quality of the
individual native species in the lake and the number of species collected on the rake. The 2015 FQI value
of 11 was within the range of values (9 to 12) observed from 2013 through 2014 (Figure 53). Plant
community quality in Horseshoe Lake is poorer than any other VBWD lake.
The annual increase in EWM extent has reduced diversity in Horseshoe Lake, as measured by the
Simpsons Diversity Index. Index values decreased from 0.80 in 2013, to 0.76 in 2014, to 0.71 in 2015
(Figure 54); i.e., the probability that two individual plants randomly selected from the Horseshoe Lake will
belong to different species has decreased from 80 percent in 2013 to 71 percent in 2015. Plant diversity in
Horseshoe Lake is poorer than any other VBWD lake.
McDonald Lake—In 2015, the McDonald Lake plant
community showed signs of recovery from the presumed
2014 illegal herbicide treatment. Plant density, frequency,
quality, and diversity improved in 2015—after the 2014
decline (Table 12 and Figures 55 through 57). The frequency
of occurrence of plants in the lake declined from 95 percent
in 2013 to 79 percent in 2014 and then increased to 88
percent in 2015 (Table 12). Plant density, measured by
average rake fullness, declined from 3.12 in 2013 to 1.92 in
2014 and then increased to 2.39 in 2015 (Table 12). The
quality of the plant community, measured by FQI, declined
from 22.3 in 2013 to 19.0 in 2014 and then increased to 19.8
in 2015 (Table 12 and Figure 56). FQI considers both the
quality of the individual native species in the lake and the
number of species collected on the rake. The diversity of the
Water quality during the 2015 plant survey
was poor, due to an algal bloom (pictured
above).
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plant community, measured by Simpson’s Diversity Index, declined from 0.85 in 2013 to 0.80 in 2014 and
then increased to 0.83 in 2015 (Table 12 and Figure 57); i.e., the probability that two individual plants
randomly selected from McDonald Lake will belong to different species increased from 80 percent in 2014
to 83 percent in 2015.
In 2015, the frequency of plant species in McDonald Lake was relatively stable. However, four plant
species (common waterweed, nitella, bald spikerush, and large-leaf pondweed) significantly increased in
frequency, while one species (small duckweed) significantly decreased in frequency (Figure 55).
Although three invasive species were present in McDonald Lake during 2015, they were not problematic.
At a frequency of 1 percent, CLP was rare—a few scattered plants were observed growing among the
waterlilies in the south basin (Figures 55 and 58). Narrow-leaved cattails were also rare (frequency of
1 percent), occurring at only a couple of sample locations along the northeastern shoreline (Figure 55).
Reed canary grass frequency in 2015 was 10 percent, which is at the low end of the 2013 to 2014 range of
10 to 15 percent (Figure 55).
Sunfish Lake—Neither invasive nor native plant species were
problematic in Sunfish Lake during 2015. Two invasive species
were present in 2015, but at a low frequency. CLP occurred at a
slightly lower frequency in 2015 (3 percent) than previous years
(4 to 6 percent) (Figure 59). Reed canary grass occurred at a
slightly higher frequency in 2015 (10 percent) than previous
years (4 to 9 percent) (Figure 59).
Of the 10 VBWD lakes surveyed in 2015, Sunfish Lake had the
highest number of native species (31 native species, Table 1).
The native plants were relatively stable in 2015, although
significant frequency changes were observed for three species:
muskgrasses, slender naiad, and leafy pondweed. The unusually
late ice-out in 2014 caused delayed growth for some species
Of the 10 VBWD lakes surveyed in
2015, Sunfish Lake (pictured above)
had the highest number of native
species.
and was the cause of the significant decline in muskgrasses.
With a return to normal ice-out and a normal growing season in 2015, muskgrasses significantly increased
in frequency (Figure 60)—returning to 2013 levels. Both slender naiad and leafy pondweed increased in
frequency in 2014, then significantly decreased in 2015, returning to 2013 levels (Figure 60).
In 2015, plant community quality, measured by FQI, improved slightly. FQI considers both the quality of
the individual native species in the lake and the number of species collected on the rake. FQI has
increased annually since 2013: from 19.5 in 2013, to 24.5 in 2014, to 24.8 in 2015 (Figure 61). The 2015
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increase in FQI was accompanied by first-time sightings of four native plant species: hardstem bulrush,
common rush, common bladderwort, and large duckweed. Diversity, measured by Simpson’s Diversity
Index, was stable in 2015. The 2015 Simpson’s Diversity Index value of 0.89 compares with 0.90 during
2013 and 2014; i.e., the probability that two individual plants randomly selected from Sunfish Lake will
belong to different species has ranged from 89 to 90 percent.
Summary
The majority of VBWD lakes had a diverse and high-quality plant community during 2015. Of the 10 lakes
surveyed, Sunfish Lake had the highest number of native species. Lake Jane had the highest quality plant
community, as measured by FQI. Lake Edith and Lake Jane had the most diverse plant communities, as
measured by Simpson’s Diversity Index. The Horseshoe Lake plant community had the fewest native
species, was less diverse, and was of poorer quality than all other VBWD lakes. Rapidly expanding EWM is
the apparent cause of the low number and quality of native species in the lake and the lack of diversity in
the plant community.
Six of the 10 surveyed VBWD lakes are infested with EWM and four were treated with herbicide: Long
Lake, Lake DeMontreville, Lake Olson, and Lake Jane. EWM frequency is highest in Horseshoe Lake (where
it has not been managed), followed by Lake Elmo. Divers removed some EWM from Lake Elmo by hand in
September of 2015.
Long Lake has been treated with herbicide nearly annually since 2011 to reduce EWM extent. All EWMinfested areas in Long Lake were treated with herbicide in 2015. The average 2,4-D concentration
measured in the lake 3 days after treatment was lethal to EWM. The 2015 treatment reduced EWM area by
93 percent. In June 2010, prior to the start of herbicide treatment, EWM extent was 52 acres, which was 97
percent of the lake’s plant growth area. After treatment in 2015, EWM extent was 0.4 acres, 0.73 percent
of the lake’s plant growth area.
In 2015, the MDNR did not permit herbicide treatment of all EWM-infested areas within Lake
DeMontreville. The total permitted area of 14 acres was only 24 percent of the 58 infested acres. The
average 2,4-D concentration measured in the lake 3 days after treatment was not lethal to EWM, but
attained seasonal control. The herbicide killed EWM plants, but not their root crowns, resulting in
regrowth of EWM later in the season. After treatment, the EWM-infested area of the lake was reduced by
64 percent. The 2015 treatment mitigated the EWM increase that occurred from June of 2014 to spring of
2015.
In 2015, the MDNR also did not permit herbicide treatment of all EWM-infested areas within Lake Olson.
The total permitted treatment area of 7 acres was only 22 percent of the 32 infested acres. Because the
treatment area was small and shallow, the quantity of herbicide allowed for the treatment was insufficient
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to attain a lethal, lake-wide 2,4-D concentration and exposure time. The average 2,4-D concentration
measured in the lake 3 days after treatment was less than one-third of the EWM lethal dose. The
treatment reduced EWM area by 11 percent, but EWM frequency increased by 4 percent. The 2015
treatment partially mitigated the EWM increase that occurred from June of 2014 to spring of 2015 and
provided some reduction in EWM area and density; however, the concentration of herbicide in the lake
was too low to reduce the EWM-infested area below 2014 levels.
The MDNR also declined to permit herbicide treatment of all EWM-infested areas within Lake Jane during
2015. The total permitted treatment area of 7.9 acres was only 18 percent of the 44 infested acres. The
average 2,4-D concentration measured 3 days after treatment was less than 20 percent of the lethal EWM
dose. The treatment reduced EWM area by 30 percent, only partially mitigating the EWM increase that
occurred from June of 2014 to spring of 2015. Hence, after treatment, the June 2015 EWM area was 29
percent greater than the June 2014 EWM area.
Herbicide treatment of EWM-infested areas within Lake Elmo was not permitted by the MDNR. In
September, the Lake Elmo Lake Association hired divers to remove EWM by hand from an area that was
less than an acre. This was about 1 percent of the 68 EWM-infested acres.
All 10 surveyed VBWD lakes are infested with CLP. However, Eagle Point Lake is the only lake with
problematic infestation. CLP was stable in Eagle Point Lake in 2015 with a density and distribution similar
to 2014 levels.
Yellow iris, an invasive species, was common on the southern shorelines of Lake DeMontreville. It appears
that residents are unaware that this is an invasive, non-native plant and are maintaining it along their
shorelines. Residents are advised to remove the yellow iris plants from their shoreline to prevent the
spread and proliferation of this invasive species.
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Description of Tables
Table 1 summarizes the results of the 2015 aquatic plant surveys of 10 VBWD lakes. The following data are
presented:

Number of species—the number of different plant species that were either collected on the rake
or observed in the lake (e.g., water lilies or cattail beds not collected on the rake but observed).
This number includes both invasive and native species.

Number of native species—the number of native plant species that were either collected on the
rake or observed in the lake.

Number of native species collected on rake—only native plants collected on the rake were
used for this statistic.

Number of invasive species—the number of invasive plant species that were either collected on
the rake or observed in the lake.

Maximum depth of plant growth—the maximum depth that plants were found in the lake.

Frequency of occurrence—the frequency with which plants were found in water shallower than
the maximum depth of plant growth.

Average rake fullness—the density of plant growth, as measured by rake fullness on a scale of
1 to 4, where:
1 = less than 1/3 of the rake head full of plants.
2 = from 1/3 to 2/3 of the rake head full of plants.
3 = more than 2/3 of the rake head full of plants.
4 = rake head is full, with plants overtopping the rake head.

Simpson Diversity Index Value—index used to measure plant diversity, which assesses the
overall health of the lake’s plant communities. The index, with scores ranging from 0 to 1,
considers both the number of species present and the evenness of species distribution. The
scores represent the probability that two individual plants randomly selected from the lake will
belong to different species. A high score indicates a more diverse plant community—a higher
probability that two randomly selected plants will represent different species.
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
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C value—scale of values used to measure the average tolerance of the plant community to
degraded conditions. Plant species are assigned C values on a scale of 0 to 10, with increasing
values indicating plants are less tolerant of degraded conditions and of better quality. An average
of the C values for individual species within a lake’s plant community indicates the average
tolerance of the community to degraded conditions.

Floristic Quality Index (FQI) value—FQI was used to assess the quality of the plant communities
in VBWD lakes. FQI considers both the quality of the individual native species found in the lake (C
value) and the number of native species collected on the rake. Although Minnesota has not kept a
record of FQI values, recorded Wisconsin FQI values range from 3 (degraded plant communities)
to 49 (diverse native plant communities). The median FQI for Wisconsin is 22.
Table 2 summarizes invasive species data from the 10 VBWD lakes surveyed in 2015. The table shows the
frequency of occurrence of species collected on the rake and mentions species that were observed but
not collected on the rake.
Tables 3 through 7 summarize Eurasian watermilfoil (EWM) extent during the period of record for Long
Lake, Lake DeMontreville, Lake Olson, Lake Jane, and Lake Elmo. EWM extent is shown as acres of EWM in
the lake and also as a percent of the plant growth area.
Tables 8 through 11 compare frequency of native species for 2014 and 2015, number of native species
collected on the rake, and both the frequency and area of EWM in Long Lake, Lake DeMontreville, Lake
Olson, and Lake Jane.
Table 12 summarizes the McDonald Lake plant community, including data on frequency of occurrence,
density, diversity, and plant community quality.
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Table 1
2015 Valley Branch Watershed District Lake Plant Survey Summary Statistics
Lake
Number
of
Species
Native
Species
Number
of Native
Species
Collected
on Rake*
Number
of
Invasive
Species
Maximum
Depth of
Plant
Growth
(feet)
Frequency of
Occurrence
Number
of
(%)
Average
Rake
Fullness
Simpson
Diversity
Index
Value
C Value
FQI
Value
Jane
30
25
24
5
23.0
96
2.37
0.92
6.4
31.4
Elmo
30
26
18
4
20.5
99
2.85
0.88
5.3
23.5
Sunfish
34
31
22
3
11.0
76
1.89
0.89
5.7
24.8
Olson
28
24
19
4
18.5
85
1.76
0.90
6.1
26.6
DeMontreville
28
23
19
5
26.5
94
1.76
0.90
6.0
26.8
McDonald
22
19
16
3
11.0
88
2.39
0.83
4.9
19.8
Eagle Point
17
14
12
3
4.0
100
3.24
0.84
5.1
19.2
Edith
22
19
16
3
12.0
91
1.51
0.92
5.4
22.1
Horseshoe
14
10
7
4
11.0
79
2.71
0.71
3.9
11.0
Long
18
14
12
4
27.0
49
1.73
0.77
5.3
16.8
Average
24
21
17
4
16.5
86
2.22
0.86
5.4
22.2
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VBWD June 2014 Point-Intercept Macrophyte Surveys
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Table 2
2015 Valley Branch Watershed District Invasive Species Summary:
Frequency of Occurrence at Sites Shallower than Maximum Depth of Plant Growth
(Percent or Observed)
Myriophyllum
spicatum
Potamogeton
crispus
Phalaris
arundinacea
Lythrum
salicaria
(purple
loosestrife)
Typha
angustifolia
(narrowleaf
cattail)
Typha
glauca
(hybrid
cattail)
Iris
pseudacorus
(yellow iris)
(Eurasian
watermilfoil)
(curly-leaf
pondweed)
(reed canary
grass)
Horseshoe
62
6
6
--
12
--
--
Elmo
45
Observed*
Observed*
--
17
--
--
Olson
28
5
Observed*
--
Observed*
--
--
DeMontreville
17
31
Observed*
--
--
1
Observed*
Jane
23
11
Observed*
Observed*
Observed*
--
--
Long
1
6
Observed*
--
--
Observed*
--
Eagle Point
--
59
Observed*
--
29
--
--
Sunfish
--
3
10
--
Observed*
--
--
Edith
--
4
1
--
--
4
--
McDonald
--
1
10
--
1
--
--
Lake
*Observed in the lake but not collected on the rake.
Table 3
Long Lake Acres of EWM, Acres of Plant Growth, and EWM Extent as a Percent of Plant
Growth Area with EWM
EWM Extent:
Acres of Plant
EWM Extent: % of Plant
Acres of EWM
Growth Area
Growth Area with EWM
6/15/2010
52.31
53.71
97.39%
Long Lake
8/1/2011
4.89
22.67
21.56%
Long Lake
4/29/2012
2.44
31.47
7.74%
Long Lake
6/18/2012
7.24
21.06
34.39%
Long Lake (Partial Survey)
5/16/2013
14.28
--
--
Long Lake
6/24/2013
7.88
50.43
15.62%
Long Lake
5/24/2014
9.75
39.94
24.41%
Long Lake
6/25/2014
4.77
47.68
10.00%
Long Lake
5/9/2015
5.5
52.81
10.41%
Long Lake
6/22/2015
0.4
54.72
0.73%
Lake
Sample Date
Long Lake
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Table 4
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VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
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Lake DeMontreville Acres of EWM, Acres of Plant Growth, and EWM Extent as a
Percent of Plant Growth Area with EWM
EWM Extent:
Acres of Plant
EWM Extent: % of Plant
Acres of EWM
Growth Area
Growth Area with EWM
6/18/2012
5.39
137.07
3.93%
Lake DeMontreville
6/24/2013
50.88
144.45
35.22%
Lake DeMontreville
5/24/2014
53.08
143.93
36.88%
Lake DeMontreville
6/28/2014
26.75
146.94
18.20%
Lake DeMontreville
5/10/2015
58.01
149.40
38.83%
Lake DeMontreville
6/21/2015
20.60
157.29
13.10%
Lake
Sample Date
Lake DeMontreville
Table 5
Lake Olson Acres of EWM, Acres of Plant Growth, and EWM Extent as a Percent of
Plant Growth Area with EWM
EWM Extent:
Acres of Plant
EWM Extent: % of Plant
Acres of EWM
Growth Area
Growth Area with EWM
6/18/2012
2.17
88.03
2.46%
Lake Olson
6/24/2013
3.55
89.01
3.99%
Lake Olson
5/24/2014
22.96
87.11
26.36%
Lake Olson
6/28/2014
23.96
89.02
26.92%
Lake Olson
5/9/2015
31.77
89.26
35.59%
Lake Olson
6/21/2015
28.13
87.02
32.33%
Lake
Sample Date
Lake Olson
Table 6
Lake Jane Acres of EWM, Acres of Plant Growth, and EWM Extent as a Percent of Plant
Growth Area with EWM
EWM Extent:
Acres of Plant
EWM Extent: % of Plant
Acres of EWM
Growth Area
Growth Area with EWM
6/18/2012
0.10
118.54
0.08%
Lake Jane
6/28/2013
1.68
121.82
1.38%
Lake Jane
6/27/2014
24.08
112.61
21.38%
Lake Jane
5/9/2015
44.16
125.08
35.31%
Lake Jane
6/21/2015
31.01
126.77
24.46%
Lake
Sample Date
Lake Jane
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Table 7
Table 8
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
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John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
2015 Lake Elmo Acres of EWM, Acres of Plant Growth, and EWM Extent as a Percent of
Plant Growth Area with EWM
EWM Extent:
Acres of Plant
EWM Extent: % of Plant
Acres of EWM
Growth Area
Growth Area with EWM
6/18-19/2012
71.09
112.68
63.09
Elmo
6/28/2013
52.69
109.61
48.07
Elmo
6/27/2014
50.58
112.42
44.99
Elmo
6/21/2015
67.52
113.53
59.47
Lake
Sample Date
Elmo
Long Lake Results: Pre-Treatment and Post-Treatment EWM and Native Species—
June 2014 and June 2015
Parameter
June 2014
June 2015
10
1
4.77
0.4
Frequency of Native Species (%)
33
47
# of Native Species Collected on the Rake
10
10
Frequency of EWM (%)
Area of EWM (acres)
Table 9
Lake DeMontreville Results: Pre-Treatment and Post-Treatment EWM and Native
Species—June 2014 and June 2015
Parameter
June 2014
June 2015
Frequency of EWM (%)
19
17
Area of EWM (acres)
27
21
Frequency of Native Species (%)
89
94
# of Native Species Collected on the Rake
19
19
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Date:
Page:
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c:
Table 10
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
25
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Lake Olson Results: Pre-Treatment and Post-Treatment EWM and Native Species—
June 2014 and June 2015
Parameter
June 2014
June 2015
Frequency of EWM (%)
28
28
Area of EWM (acres)
24
28
Frequency of Native Species (%)
91
82
# of Native Species Collected on the Rake
20
19
Table 11
Lake Jane Results: Pre-Treatment and Post-Treatment EWM and Native Species—
June 2014 and June 2015
Parameter
June 2014
June 2015
Frequency of EWM (%)
19
23
Area of EWM (acres)
24
31
Frequency of Native Species (%)
99
96
# of Native Species Collected on the Rake
28
24
Table 12
2013–2015 McDonald Lake Frequency, Density, Diversity, and Quality of Plant
Community
Frequency of
Density (Average
Simpson Diversity
Plant Community
Occurrence* (%)*
Rake Fullness)
Index
Quality (FQI)
6/27/2013
95
3.12
0.85
22.3
6/26/2014
79
1.92
0.80
19.0
6/23/2015
88
2.39
0.83
19.8
Sample Date
*Frequency of occurrence at sites shallower than maximum depth of plant growth
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VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
26
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Description of Figures

Figures 1, 12, 20, and 28 show the 2015 herbicide treatment areas for Long Lake, Lake
DeMontreville, Lake Olson, and Lake Jane.

Figure 2 shows the percent of EWM-infested area treated with herbicide in Long Lake, Lake
DeMontreville, Lake Olson, and Lake Jane.

Figure 3 compares the 2,4-D concentrations measured in the treated lakes with the 2,4-D dose
that is lethal to EWM.

Figure 4 compares the May 2015 (pre-treatment) EWM area with the June 2015 (post-treatment)
EWM area in the treated lakes and notes the percent reduction in EWM area for each lake.

Figures 5, 13, 21, and 29 summarize EWM area in treated lakes for the period of record.

Figures 6, 14, 22, and 30 summarize EWM frequency in treated lakes for the period of record.

Figures 7, 15, 23, and 31 compare pre- and post-treatment EWM rake fullness in lakes treated in
2015.

Figure 45 shows EWM extent in Lake Elmo during 2015.

Figure 50 summarizes the EWM frequency in Horseshoe Lake for 2013 through 2015.

Figures 11, 19, 27, 35, 36, 43, 46, 51, 58 and 59 summarize the curly-leaf pondweed frequency for
the period of record in the 10 VBWD lakes surveyed in 2015.

Figures 8, 16, 24, 32, 37, 40, 47, 52, 55, and 60 summarize the frequency of occurrence of
individual plant species observed in the 10 VBWD lakes that were surveyed in 2015. The figures
show species frequency for the entire period of record. The figures denote significant changes in
frequency between years with asterisks. The number of asterisks denotes the degree of
confidence that the change is not due to chance. One asterisk indicates a 95 percent confidence,
two asterisks indicate a 99 percent confidence, and three asterisks indicate a 99.9-percent
confidence.

Figures 9, 17, 25, 33, 38, 41, 48, 53, 56, and 61 summarize the FQI values during the period of
record for the 10 VBWD lakes surveyed in 2015.

Figures 10, 18, 26, 34, 39, 42, 49, 54, 57, and 62 summarize Simpson’s Diversity Index values
during the period of record for the 10 VBWD lakes surveyed in 2015.
D
D
D
D
D
D
D
D
D
Treatment Area 3
1.19 acres
Avg. Depth: 11.2 ft
D
D
D
D
D
D
D
Treatment Area 2
1.12 acres
Avg. Depth: 11.5 ft
D
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36
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Treatment Area 1
6.01 acres
Avg. Depth: 7.0 ft
D
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Treatment Area 7
2.84 acres
Avg. Depth: 8.2 ft
(
!
D
D
D
D
D
D
D
D
D
D
Treatment Area 6
2.34 acres
Avg. Depth: 12.1 ft
D
D
D
D
Long Lake Rd
D
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D
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D
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Treatment Area 5
0.89 acres
Avg. Depth: 8.7 ft
D
D
D
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Warner Ave S
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Barr Footer: ArcGIS 10.3.1, 2015-10-02 10:28 File: I:\Client\VBWD\District\Work_Orders\Lake_Monitoring\Maps\Reports\2015\Data Summary Report\Figure 1 - Eurasin Watermilfoil (EWM) Treatment Areas, May 2015 Survey Results and Herbicide Residue Monitoring Locations - Long Lake.mxd User: KAC2
g
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Treatment Area 4
5.62 acres
Avg. Depth: 5.2 ft
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694
694
Service Layer Credits: Source: Esri, DigitalGlobe, GeoEye, Earthstar
Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping,
EWM Survey Results
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Figure 1
Herbicide Residue
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N
0
125
Prepared by Margaret Rattei and Kelly Wild, Barr Engineering, for Valley Branch
Watershed District based on results of a survey done by Matt Berg on May 9, 2015.
The Valley Branch Watershed District prepared this map to assist the Friends of Long Lake.
Feet
250
500
EURASIAN WATERMILFOIL
TREATMENT AREAS, MAY 2015
PLANT SURVEY RESULTS AND
HERBICIDE RESIDUE MONITORING
LOCATIONS
Long Lake (82011800)
Washington County
Valley Branch Watershed District
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VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
28
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
% of EWM Extent Treated with 2,4-D Per DNR Permit
100
100
90
MDNR restricted the herbicide treatment area to
15% of the plant growth area (littoral zone) for Lake
DeMontreville, Lake Olson, and Lake Jane
80
70
60
50
40
30
24
18
10
0
Long Lake
Figure 2
22
20
Lake DeMontreville
Lake Olson
Percentage of EWM Area Treated with 2,4-D in 2015 per MDNR Permit
Lake Jane
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VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
29
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
2,4-D Concentration (ppm, ae*)
0.8
2,4-D Concentration at 3 Days after Treatment
0.7
2,4-D Dose Lethal to EWM for 3 Day Exposure
Time = 0.5 ppm ae*
0.6
0.5
0.4
0.3
0.2
0.1
0
Figure 3
0.676
*acid equivalent (ae) is a
measure of the amount of 2,4D acid applied - the ingredient
within 2,4-D that binds to
EWM and kills the plant.
0.185
0.156
0.081
Comparison of Lethal 2,4-D Dose with Herbicide Residue Data (3 Days after Treatment)
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VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
30
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
70.0
Pre-Treatment EWM Extent
58.0
60.0
EWM Extent (Acres)
Post-Treatment EWM Extent
50.0
44.2
11% EWM
Reduction
40.0
64% EWM
Reduction
30.0
31.8
30% EWM
Reduction
31.0
28.1
20.6
20.0
10.0
93% EWM
Reduction
5.5
0.4
0.0
Long Lake
Figure 4
Lake DeMontreville
Lake Olson
Lake Jane
May 2015 Pre-Treatment and June 2015 Post-Treatment EWM Extent
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VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
31
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
60
EWM Extent (acres)
50
Herbicide treatments occurred in early spring of 2011, 2013, 2014, and 2015
40
30
52.3
20
10
14.3
4.9
2.4
7.2
7.9
0
Figure 5
2010–2015 Long Lake Eurasian Watermilfoil Extent
9.8
4.8
5.5
0.4
Frequency of Occurrence at Sites Shallower than
Maximum Depth of Plant Growth (%)
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Project:
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VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
32
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
100
Herbicide treatments occurred in early spring of 2011, 2013, 2014, and 2015
90
80
70
60
50
92
40
71
30
20
29
29
10
28
19
10
10
11
1
0
Figure 6
20102015 Long Lake Eurasian Watermilfoil Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth
To:
From:
Subject:
Date:
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c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
33
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
16
14
Number of Sites
12
Pre-treatment (5/9/2015)
10
Post-treatment (June 22, 2015)
8
6
4
2
0
All EWM
Figure 7
EWM Rake
Fullness 1
EWM Rake
Fullness 2
EWM Rake
Fullness 3
Long Lake: 2015 Pre- and Post-Treatment EWM Rake Fullness
EWM Rake
Fullness 4
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VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
34
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
2010-2015 Long Lake: Frequency of Occurrence
100
* means p < 0.05 (95 % Confidence Difference is Significant)
** means p < 0.01 (99% Confidence Difference is Significant)
*** means p < 0.001 (99.9% Confidence Difference is Significant)
2010
2011
80
2012
*
2013
70
2014
2015
60
50
***
40
***
***
*
***
*
**
Hybrid cattail
Nitella
River bulrush
Large duckweed
Willow
Northern watermilfoil
Cattail
Reed canary grass
Hardstem bulrush
Needle spikerush
Small duckweed
Coontail
Note: * indicates a significant change in frequency of occurrence between years
Figure 8
2010–2015 Long Lake Frequency of Occurrence in Plant Growth Area of the Lake
Common watermeal
*
*
Muskgrasses
Slender naiad
Curly-leaf pondweed
**
**
*
Forked duckweed
***
Water star-grass
**
Eurasian watermilfoil
0
** ***
***
***
Aquatic moss
***
**
10
Filamentous algae
20
Common waterweed
30
Small pondweed
Frequency of Occurrence (%)
90
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From:
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c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
35
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
35.0
30.0
FQI Values
25.0
20.0
15.0
10.0
14.1
18.5
17.7
17.4
16.8
6/18/2012
6/24/2013
6/25/2014
6/22/2015
15.7
5.0
0.0
6/15/2010
Figure 9
8/1/2011
2010–2015 Long Lake Floristic Quality Index (FQI) Values
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From:
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Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
36
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Simpson Diversity Index Values
1.00
0.80
0.60
0.40
0.20
0.80
0.85
0.81
0.83
6/24/2013
6/25/2014
0.77
0.40
0.00
6/15/2010
Figure 10
8/1/2011
6/18/2012
2010–2015 Long Lake Simpson Diversity Index Values
6/22/2015
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From:
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VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
37
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth (%)
45
40
35
30
25
41
20
15
25
10
11
5
6
0
6/15/2010
Figure 11
6
2
8/1/2011
6/8/2012
6/24/2013 6/27/2014 6/22/2015
2010–2015 Long Lake Curly-leaf Pondweed Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth
la
s
nd
il A
ve
N
N
Tr
Treatment Area A
3.2 acres
Avg. Depth: 6.5 ft
S
53rd
Demontreville Tr N
N
Tr
ds
n
a
hl
Hig
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13B
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Treatment Area B
1.4 acres
Avg. Depth: 4.5 ft
Hill Trail Ct N
Treatment Area C
3.0 acres
Avg. Depth: 4.2 ft
D-2
(
!
$
1
Hill Tr N
(
!
50th St N
35
7
6
5
4
13
Treatment Area D
6.4 acres
Avg. Depth: 6.8 ft
.
!
D-1
(
!
D
Tr
N
7
6
5
4
ay
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Hid
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Barr Footer: ArcGIS 10.3.1, 2015-10-02 10:29 File: I:\Client\VBWD\District\Work_Orders\Lake_Monitoring\Maps\Reports\2015\Data Summary Report\Figure 12 - Eurasian Watermilfoil (EWM) Treatment Areas, May 2015 Survey Results, and Herbicide Residue Monitoring Locations - Lake DeMontreville.mxd User: KAC2
gh
Hi
yt
ra
Highlands Ct N
H
Upper 45th St N
Windbreak Tr N
Service Layer Credits: Source: Esri, DigitalGlobe, GeoEye, Earthstar
Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping,
EWM Survey Results
D
Not Observed
.
!
Visual Only
(
!
Density = 1
(
!
Density = 2
(
!
Density = 3
(
!
Figure 12
Density = 4
;
!
Treatment Area
$
1
Herbicide Residue
Monitoring Location
N
0
225
Feet
450
Prepared by Margaret Rattei and Kelly Wild, Barr Engineering, for Valley Branch
Watershed District based on results of a survey done by Matt Berg on May 9, 2015.
The Valley Branch Watershed District prepared this map to assist the Lake DeMontreville/Olson Association.
900
EURASIAN WATERMILFOIL
TREATMENT AREAS, MAY 2015
PLANT SURVEY RESULTS AND
HERBICIDE RESIDUE MONITORING
LOCATIONS
Lake DeMontreville (82010100)
Washington County
Valley Branch Watershed District
To:
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VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
39
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
70
Small-scale herbicide treatments occurred in early spring of 2014 and 2015
60
EWM Extent (acres)
50
40
30
58.0
50.9
53.1
20
26.8
20.6
10
5.4
0
6/18/2012
Figure 13
6/24/2013
5/24/2014
6/28/2014
5/10/2015
2012–2015 Lake DeMontreville Eurasian Watermilfoil Extent
6/21/2015
To:
From:
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VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
40
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower than
Maximum Depth of Plant Growth (%)
40
Small-scale herbicide treatments occurred in early spring of 2014 and 2015
35
30
25
20
33
35
34
15
10
19
17
5
4
0
6/18/2012
6/24/2013
5/24/2014
6/28/2014
5/10/2015
6/21/2015
To:
From:
Subject:
Date:
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Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
41
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Figure 14
2012–2015 Lake DeMontreville Eurasian Watermilfoil Frequency of Occurrence at Sites
Shallower than Maximum Depth of Plant Growth
40
35
Number of Sites
30
Pre-treatment (May 10, 2015)
25
Post-treatment (June 21, 2015)
20
15
10
5
0
All EWM
Figure 15
EWM Rake
Fullness 1
EWM Rake
Fullness 2
EWM Rake
Fullness 3
Lake DeMontreville: 2015 Pre- and Post-Treatment Rake Fullness
EWM Rake
Fullness 4
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
42
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
2012-2015 Lake DeMontreville: Frequency of Occurrence
70
2012
* means p < 0.05 (95 % Confidence Difference is Significant)
** means p < 0.01 (99% Confidence Difference is Significant)
*** means p < 0.001 (99.9% Confidence Difference is Significant)
60
2013
2014
2015
Frequency of Occurrence (%)
50
40
***
***
30
***
*
*
**
20
*
**
10
***
*
*
Sago pondweed
Spiny spored-quillwort
Large duckweed
Fries' pondweed
Softstem bulrush
Southern naiad
Small duckweed
Aquatic moss
Hybrid cattail
Common watermeal
Needle spikerush
Reed canary grass
Slender naiad
Wild celery
White water lily
Large-leaf pondweed
White water crowfoot
Eurasian watermilfoil
Water star-grass
Muskgrasses
Filamentous algae
Common waterweed
Nitella
Illinois pondweed
Fern pondweed
Forked duckweed
Coontail
Small pondweed
Curly-leaf pondweed
Flat-stem pondweed
Northern watermilfoil
***
0
Note: * indicates a significant change in frequency of occurrence between years
Figure 16
2012–2015 Lake DeMontreville Frequency of Occurrence in Plant Growth Area of the Lake
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
43
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Floristic Quality Index (FQI) Values
35.0
30.0
25.0
20.0
15.0
25.0
26.2
26.8
26.8
6/24/2013
6/28/2014
6/21/2015
10.0
5.0
0.0
6/18/2012
Figure 17
2012–2015 Lake DeMontreville Floristic Quality Index (FQI) Values
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
44
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Simpson Diversity Index Values
1.00
0.80
0.60
0.89
0.90
0.90
0.90
6/18/2012
6/24/2013
6/28/2014
6/21/2015
0.40
0.20
0.00
Figure 18
2012–2015 Lake DeMontreville Simpson Diversity Index Values
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
45
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth (%)
60
50
40
30
49
42
20
31
10
10
0
6/18/2012
Figure 19
6/24/2013
6/28/2014
6/21/2015
2012–2015 Lake DeMontreville Curly-leaf Pondweed Frequency of Occurrence at Sites
Shallower than Maximum Depth of Plant Growth
Hill Tr N
13B
Hill T
rN
©
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50th St N
7
6
5
4
35
Hillv
ale
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Treatment Area A
7.0 acres
Avg. Depth: 7.6 ft
N
7
6
5
4
13
Hillvale Way N
.
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et
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N
44th St
44th
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Hidde
n Bay
Tr N
Hillvale Ave N
Upper 45th St N
44th
Ct N
Barr Footer: ArcGIS 10.3.1, 2015-08-28 14:38 File: I:\Client\VBWD\District\Work_Orders\Lake_Monitoring\Maps\Reports\2015\Data Summary Report\Figure 3 - Eurasian Watermilfoil (EWM) Treatment Areas and May 2015 Survey Results and Herbicide Residue Monitoring Locations - Lake Olson.mxd User: KAC2
Hill Trail Ct N
Deer Pond Tr N
Service Layer Credits: Source: Esri, DigitalGlobe, GeoEye, Earthstar
Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping,
EWM Survey Results
D
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Figure 20
Herbicide Residue
Monitoring Location
;
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N
0
175
Feet
350
Treatment Area
Prepared by Margaret Rattei and Kelly Wild, Barr Engineering, for Valley Branch
Watershed District based on results of a survey done by Matt Berg on May 9, 2015.
The Valley Branch Watershed District prepared this map to assist the Lake DeMontreville/Olson Association.
700
EURASIAN WATERMILFOIL
TREATMENT AREAS, MAY 2015
PLANT SURVEY RESULTS AND
HERBICIDE RESIDUE MONITORING
LOCATIONS
Lake Olson (82010300)
Washington County
Valley Branch Watershed District
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
47
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
35.0
30.0
Small-scale herbicide treatments occurred
in early spring of 2014 and 2015
EWM Extent (acres)
25.0
20.0
31.8
15.0
28.1
23.0
24.0
5/24/2014
6/28/2014
10.0
5.0
2.2
3.6
0.0
6/18/2012
Figure 21
6/24/2013
2012–2015 Lake Olson Eurasian Watermilfoil Extent
5/9/2015
6/21/2015
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From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
48
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower than
Maximum Depth of Plant Growth (%)
30
25
20
Small-scale herbicide
treatments occurred in
early spring of 2014 and
2015
15
28
26
27
28
10
5
3
5
0
6/18/2012
Figure 22
6/24/2013
5/24/2014
6/28/2014
5/9/2015
6/21/2015
2012–2015 Lake Olson Eurasian Watermilfoil Frequency of Occurrence at Sites
Shallower than Maximum Depth of Plant Growth
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
49
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
35
30
Pre-treatment (5/9/2015)
25
Number of Sites
Post-treatment (6/21/2015)
20
15
10
5
0
All EWM
Figure 23
EWM Rake
Fullness 1
EWM Rake
Fullness 2
Lake Olson: 2015 Pre- and Post-Treatment Rake Fullness
EWM Rake
Fullness 3
EWM Rake
Fullness 4
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
50
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
2012-2015 Lake Olson: Frequency of Occurrence
60
2012
* means p < 0.05 (95 % Confidence Difference is Significant)
** means p < 0.01 (99% Confidence Difference is Significant)
*** means p < 0.001 (99.9% Confidence Difference is Significant)
**
2013
2014
50
2015
*
**
30
***
**
*
*
*
20
*
**
**
*
***
***
Note: * indicates a significant change in frequency of occurrence between years
Figure 24
2012–2015 Lake Olson Frequency of Occurrence in Plant Growth Area of the Lake
Long-leaf pondweed
Filamentous algae
Aquatic moss
Wild celery
Softstem bulrush
White water crowfoot
Flat-stem pondweed
Illinois pondweed
Large-leaf pondweed
***
Curly-leaf pondweed
Reed canary grass
White water lily
Nitella
Southern naiad
Slender naiad
*
Eurasian water milfoil
Forked duckweed
Spiny-spored quillwort
Water star-grass
Common waterweed
Creeping spikerush
Needle spikerush
Muskgrasses
Coontail
0
Northern water-milfoil
*
Fern pondweed
10
Small pondweed
Frequency of Occurrence (%)
*
40
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Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
51
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
35.0
Floristic Quality Index (FQI) Values
30.0
25.0
20.0
15.0
28.0
25.9
25.2
6/18/2012
6/24/2013
26.6
10.0
5.0
0.0
Figure 25
6/28/2014
2012–2015 Lake Olson Floristic Quality Index (FQI) Values
6/21/2015
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
52
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
1.00
Simpson Diversity Index Values
0.80
0.60
0.92
0.91
0.90
0.90
6/18/2012
6/24/2013
6/28/2014
6/21/2015
0.40
0.20
0.00
Figure 26
2012–2015 Lake Olson Simpson Diversity Index Values
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
53
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth (%)
45
40
35
30
25
43
20
15
28
10
5
0
6/18/2012
Figure 27
6/24/2013
3
5
6/28/2014
6/21/2015
2012–2015 Lake Olson Curly-leaf Pondweed Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth
Barr Footer: ArcGIS 10.3.1, 2015-10-02 10:29 File: I:\Client\VBWD\District\Work_Orders\Lake_Monitoring\Maps\Reports\2015\Data Summary Report\Figure 28 - Eurasin Watermilfoil (EWM) Treatment Areas, May 2015 Survey Results, and Herbicide Residue Monitoring Locations - Lake Jane.mxd User: KAC2
Treatment Area B
3.5 acres
Avg. Depth: 3.7 ft
J-2
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Treatment Area C
1.1 acres
Avg. Depth: 5.0 ft
(
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$
1
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J-3
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Treatment Area A
2.7 acres
Avg. Depth: 3.3 ft
Treatment Area D
0.6 acres
Avg. Depth: 5.5 ft
Service Layer Credits: Source: Esri, DigitalGlobe, GeoEye, Earthstar
Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping,
EWM Survey Results
D
Not Observed
.
!
Visual Only
(
!
Density = 1
(
!
Density = 2
(
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Density = 3
Figure 28
Treatment Area
$
1
;
!
Herbicide Residue
Monitoring Location
N
0
250
Feet
500
Prepared by Margaret Rattei and Kelly Wild, Barr Engineering, for Valley Branch
Watershed District based on results of a survey done by Matt Berg on May 9, 2015.
The Valley Branch Watershed District prepared this map to assist the Lake Jane Association.
1,000
EURASIAN WATERMILFOIL
TREATMENT AREAS, MAY 2015
PLANT SURVEY RESULTS AND
HERBICIDE RESIDUE MONITORING
LOCATIONS
Lake Jane (82010400)
Washington County
Valley Branch Watershed District
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
55
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
50.0
45.0
Small-scale herbicide treatment occurred in early
spring of 2015
40.0
EWM Extent (acres)
35.0
30.0
25.0
44.2
20.0
31.0
15.0
24.1
10.0
5.0
0.1
1.7
6/18/2012
6/28/2013
0.0
Figure 29
6/27/2014
2012–2015 Lake Jane Eurasian Watermilfoil Extent
5/9/2015
6/21/2015
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
56
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower than
Maximum Depth of Plant Growth (%)
35
30
Small-scale herbicide treatment occurred in early
spring of 2015
25
20
32
15
23
10
19
5
0
2
6/18/2012
6/28/2013
0
Figure 30
6/27/2014
5/9/2015
6/21/2015
2012–2015 Lake Jane Eurasian Watermilfoil Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
57
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
30
Number of Sites
25
20
Pre-treatment (5/9/2015)
Post-treatment (6/21/2015)
15
10
5
0
All EWM
Figure 31
EWM Rake
Fullness 1
EWM Rake
Fullness 2
Lake Jane: 2015 Pre- and Post-Treatment Rake Fullness
EWM Rake
Fullness 3
EWM Rake
Fullness 4
Fern pondweed
Coontail
Common waterweed
Illinois pondweed
Northern watermilfoil
Large-leaf pondweed
Muskgrasses
Curly-leaf pondweed
Flat-stem pondweed
White water crowfoot
White-stem pondweed
Slender naiad
Small pondweed
Water star-grass
Southern naiad
White water lily
Wild celery
Needle spikerush
Brown-fruited rush
Small duckweed
Crested arrowhead
Filamentous algae
Watershield
Forked duckweed
Fries' pondweed
Sago pondweed
Common watermeal
Broad-leaved woolly sedge
Bald spikerush
Spiny spored-quillwort
Baltic rush
Canada rush
Eurasian watermilfoil
Nitella
Long-leaf pondweed
Softstem bulrush
Horned pondweed
Aquatic moss
Water marigold
Frequency of Occurrence (%)
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
58
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
2012-2015 Lake Jane: Frequency of Occurrence
70
60
* means p < 0.05 (95 % Confidence Difference is Significant)
** means p < 0.01 (99% Confidence Difference is Significant)
*** means p < 0.001 (99.9% Confidence Difference is Significant)
20
*
10
0
Figure 32
2012
2013
2014
50
2015
40
30
**
***
*
*
**
Note: * indicates a significant change in frequency of occurrence between years
2012–2015 Lake Jane Frequency of Occurrence in Plant Growth Area of the Lake
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
59
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
35.0
Floristic Quality Index (FQI) Values
30.0
25.0
20.0
15.0
31.0
32.7
32.0
31.4
6/28/2013
6/27/2014
6/21/2015
10.0
5.0
0.0
6/18/2012
Figure 33
2012–2015 Lake Jane Floristic Quality Index (FQI) Values
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
60
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
1.00
Simpson Diversity Index Values
0.80
0.60
0.92
0.91
0.92
0.92
6/18/2012
6/28/2013
6/27/2014
6/21/2015
0.40
0.20
0.00
Figure 34
2012–2015 Lake Jane Simpson Diversity Index Values
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
61
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth (%)
20
15
10
16
12
11
5
8
0
6/18/2012
Figure 35
6/28/2013
6/27/2014
6/21/2015
2012–2015 Lake Jane Curly-leaf Pondweed Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
62
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth (%)
90
80
70
60
50
40
79
30
58
54
59
20
10
0
6/19/2012
Figure 36
6/27/2013
6/26/2014
6/23/2015
2012–2015 Eagle Point Lake Curly-leaf Pondweed Frequency of Occurrence at Sites
Shallower than Maximum Depth of Plant Growth
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
63
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
2012-2015 Eagle Point Lake: Frequency of Occurrence
90
* means p < 0.05 (95 % Confidence Difference is Significant)
** means p < 0.01 (99% Confidence Difference is Significant)
*** means p < 0.001 (99.9% Confidence Difference is Significant)
80
Frequency of Occurrence (%)
2013
2014
2015
***
70
60
2012
**
*
***
**
50
***
40
**
**
30
***
***
*
*
20
***
*
***
*
*
Fries' pondweed
**
Flat-stem pondweed
Forked duckweed
Muskgrasses
Common bladderwort
Slender riccia
Softstem bulrush
Nitella
Leafy pondweed
Filamentous algae
Sago pondweed
Small duckweed
Large duckweed
*
Horned pondweed
Narrow-leaved cattail
Small pondweed
Coontail
Common waterweed
Curly-leaf pondweed
River bulrush
*
0
Slender naiad
10
Note: * indicates a significant change in frequency of occurrence between years
Figure 37
2012–2015 Eagle Point Lake Frequency of Occurrence in Plant Growth Area of the Lake
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
64
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
35.0
30.0
Floristic Quality Index (FQI) Values
25.0
20.0
15.0
10.0
18.7
20.7
22.6
19.2
5.0
0.0
6/19/2012
Figure 38
6/27/2013
6/26/2014
2012–2015 Eagle Point Lake Floristic Quality Index (FQI) Values
6/23/2015
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
65
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
1.00
Simpson Diversity Index Values
0.80
0.60
0.40
0.84
0.88
0.85
0.84
6/27/2013
6/26/2014
6/23/2015
0.20
0.00
6/19/2012
Figure 39
2012–2015 Eagle Point Lake Simpson Diversity Index Values
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
66
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
2013-2015 Lake Edith: Frequency of Occurrence
60
2013
* means p < 0.05 (95 % Confidence Difference is Significant)
** means p < 0.01 (99% Confidence Difference is Significant)
*** means p < 0.001 (99.9% Confidence Difference is Significant)
2014
2015
40
30
**
20
**
10
*
***
Note: * indicates a significant change in frequency of occurrence between years
Figure 40
2013–2015 Lake Edith Frequency of Occurrence in Plant Growth Area of the Lake
Water star-grass
Reed canary grass
Common watermeal
Softstem bulrush
Purple-fringed riccia
Small pondweed
Hybrid cattail
Wild celery
Curly-leaf pondweed
Flat-stem pondweed
Spatterdock
Fries' pondweed
Small duckweed
Filamentous algae
Horned pondweed
Muskgrasses
Illinois pondweed
Slender naiad
Sago pondweed
Coontail
0
Large duckweed
*
Northern water-milfoil
Frequency of Occurrence (%)
50
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
67
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
35.0
30.0
Floristic Quality Index (FQI) Values
25.0
20.0
15.0
10.0
21.8
19.8
22.1
5.0
0.0
6/28/2013
Figure 41
6/30/2014
2013–2015 Lake Edith Floristic Quality Index (FQI) Values
6/24/2015
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
68
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
1.00
Simpson Diversity Index Values
0.80
0.60
0.89
0.88
6/28/2013
6/30/2014
0.92
0.40
0.20
0.00
Figure 42
2013–2015 Lake Edith Simpson Diversity Index Values
6/24/2015
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
69
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth (%)
20
15
10
5
4
4
4
6/28/2013
6/30/2014
6/24/2015
0
Figure 43
2013–2015 Lake Edith Curly-leaf Pondweed Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
70
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth (%)
50
45
40
35
30
25
45
44
20
37
15
34
10
5
0
6/18/2012
Figure 44
6/28/2013
6/27/2014
6/21/2015
2012–2015 Lake Elmo Eurasian Watermilfoil Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth
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Barr Footer: ArcGIS 10.3.1, 2015-10-02 10:29 File: I:\Client\VBWD\District\Work_Orders\Lake_Monitoring\Maps\Reports\2015\Data Summary Report\Figure 45 - Lake Elmo Eurasian Watermilfoil Extent - June 2015.mxd User: KAC2
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Service Layer Credits: Source: Esri, DigitalGlobe, GeoEye, Earthstar
Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping,
EWM Sample Locations (June 2015)
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Figure 45
Additional Canopied EWM Beds
;
!
Maximum Depth of Plant Growth
N
Approximate Extent of EWM
0
300
Feet
600
1,200
LAKE ELMO EURASIAN
WATERMILFOIL EXTENT,
JUNE 2015
Lake Elmo (82010600)
Washington County
Valley Branch Watershed District
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
72
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth (%)
20
15
10
5
3
0
6/18/2012
Figure 46
0
0
0
6/28/2013
6/27/2014
6/21/2015
2013–2015 Lake Elmo Curly-leaf Pondweed Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
73
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
2012-2015 Lake Elmo: Frequency of Occurrence
50
45
*
* means p < 0.05 (95 % Confidence Difference is Significant)
** means p < 0.01 (99% Confidence Difference is Significant)
*** means p < 0.001 (99.9% Confidence Difference is Significant)
40
2012
2013
2014
2015
Frequency of Occurrence (%)
35
30
25
20
15
10
5
Eurasian watermilfoil
Muskgrasses
Coontail
Southern naiad
Narrow-leaved cattail
Illinois pondweed
White water lily
Floating-leaf pondweed
Common waterweed
Flat-stem pondweed
White water crowfoot
Softstem bulrush
Sago pondweed
Filamentous algae
Reed canary grass
Hardstem bulrush
Needle spikerush
Creeping spikerush
Curly-leaf pondweed
Bald spikerush
Small duckweed
Northern watermilfoil
Slender naiad
Nitella
Small pondweed
Stiff pondweed
Common bladderwort
Broad-leaved wooly sedge
Broom sedge
Southern blue flag
Common reed
Fries' pondweed
Large duckweed
Slender riccia
Water star-grass
0
Note: * indicates a significant change in frequency of occurrence between years
Figure 47
2012–2015 Lake Elmo Frequency of Occurrence in Plant Growth Area of the Lake
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
74
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
35.0
30.0
Floristic Quality Index (FQI) Values
25.0
20.0
15.0
26.1
22.8
10.0
23.5
20.4
5.0
0.0
6/18/2012
Figure 48
6/28/2013
6/27/2014
2012–2015 Lake Elmo Floristic Quality Index (FQI) Values
6/21/2015
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
75
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
1.00
Simpson Diversity Index Values
0.80
0.60
0.91
0.89
0.88
0.88
6/18/2012
6/28/2013
6/27/2014
6/21/2015
0.40
0.20
0.00
Figure 49
2012–2015 Lake Elmo Simpson Diversity Index Values
Frequency of Occurrence at Sites Shallower than
Maximum Depth of Plant Growth (%)
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
76
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
70
60
50
40
62
30
20
40
10
10
0
6/27/2013
Figure 50
6/30/2014
6/22/2015
2013–2015 Horseshoe Lake Eurasian Watermilfoil Frequency of Occurrence at Sites
Shallower than Maximum Depth of Plant Growth
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
77
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth (%)
20
15
10
5
7
6
4
0
6/27/2013
Figure 51
6/30/2014
6/22/2015
2013–2015 Horseshoe Lake Curly-leaf Pondweed Frequency of Occurrence at Sites
Shallower than Maximum Depth of Plant Growth
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
78
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
2013-2015 Horseshoe Lake: Frequency of Occurrence
70
* means p < 0.05 (95 % Confidence Difference is Significant)
** means p < 0.01 (99% Confidence Difference is Significant)
*** means p < 0.001 (99.9% Confidence Difference is Significant)
**
60
2013
2014
2015
Frequency of Occurrence (%)
50
***
40
30
20
10
*
Flat-stem pondweed
River bulrush
Broad-leaved cattail
Softstem bulrush
Water star-grass
Muskgrasses
Curly-leaf pondweed
Small pondweed
Common waterweed
Reed canary grass
Eurasian watermilfoil
Filamentous algae
Narrow-leaved cattail
Sago pondweed
Coontail
0
Note: * indicates a significant change in frequency of occurrence between years
Figure 52
2013–2015 Horseshoe Lake Frequency of Occurrence in Plant Growth Area of the Lake
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
79
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
25.0
FQI Values
20.0
15.0
10.0
12.0
5.0
11.0
9.0
0.0
6/27/2013
Figure 53
6/30/2014
2013–2015 Horseshoe Lake Floristic Quality Index (FQI) Values
6/22/2015
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
80
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
1.00
Simpson Diversity Index Values
0.80
0.60
0.40
0.80
0.76
0.71
0.20
0.00
6/27/2013
Figure 54
6/30/2014
2013–2015 Horseshoe Lake Simpson Diversity Index Values
6/22/2015
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
81
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
2013-2015 McDonald Lake: Frequency of Occurrence
70
* means p < 0.05 (95 % Confidence Difference is Significant)
** means p < 0.01 (99% Confidence Difference is Significant)
*** means p < 0.001 (99.9% Confidence Difference is Significant)
60
2013
2014
2015
40
***
30
***
***
20
*
Bald spikerush
Nitella
Common rush
Small duckweed
Large duckweed
Filamentous algae
Sessile-fruited arrowhead
Woolgrass
Aquatic moss
Illinois pondweed
Common arrowhead
Southern blue flag
Broom sedge
*
Needle spikerush
Narrow-leaved cattail
Broad-leaved woolly sedge
Spiral-fruited pondweed
*
*
***
Spatterdock
*
Slender riccia
Watershield
**
Water smartweed
Curly-leaf pondweed
**
Reed canary grass
Common waterweed
Coontail
White water lily
Common bladderwort
***
0
*
Creeping spikerush
***
Small bladderwort
**
Large-leaf pondweed
***
10
Small pondweed
Frequency of Occurrence (%)
50
Note: * indicates a significant change in frequency of occurrence between years
Figure 55
2013–2015 McDonald Lake Frequency of Occurrence in Plant Growth Area of the Lake
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
82
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
35.0
Floristic Quality Index (FQI) Values
30.0
25.0
20.0
15.0
10.0
22.3
19.0
19.8
6/26/2014
6/23/2015
5.0
0.0
6/27/2013
Figure 56
2013–2015 McDonald Lake Floristic Quality Index (FQI) Values
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
83
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
1.00
Simpson Diversity Index Values
0.80
0.60
0.40
0.85
0.80
0.83
6/26/2014
6/23/2015
0.20
0.00
6/27/2013
Figure 57
2013–2015 McDonald Lake Simpson Diversity Index Values
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
84
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth (%)
20
15
10
5
8
2
1
6/26/2014
6/23/2015
0
6/27/2013
Figure 58
2013–2015 McDonald Lake Curly-leaf Pondweed Frequency of Occurrence at Sites
Shallower than Maximum Depth of Plant Growth
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
85
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
Frequency of Occurrence at Sites Shallower
than Maximum Depth of Plant Growth (%)
20
15
10
5
6
4
3
0
6/28/2013
Figure 59
6/28/2013
6/28/2013
2013–2015 Sunfish Lake Curly-leaf Pondweed Frequency of Occurrence at Sites
Shallower than Maximum Depth of Plant Growth
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
86
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
2013-2015 Sunfish Lake: Frequency of Occurrence
50
* means p < 0.05 (95 % Confidence Difference is Significant)
** means p < 0.01 (99% Confidence Difference is Significant)
*** means p < 0.001 (99.9% Confidence Difference is Significant)
45
40
2013
2014
2015
30
25
**
20
*
15
10
***
*
5
Note: * indicates a significant change in frequency of occurrence between years
Figure 60
2013–2015 Sunfish Lake Frequency of Occurrence in Plant Growth Area of the Lake
Filamentous algae
Common bladderwort
Commmon rush
Large duckweed
Hardstem bulrush
Fries' pondweed
Northern manna grass
Woolgrass
Needle spikerush
Baltic rush
Slender naiad
Water star-grass
Broom sedge (likely)
Fowl mannagrass (likely)
Creeping spikerush
Narrow-leaved cattail
Softstem bulrush
Broad-leaved wooly sedge
Common arrowhead
White water lily
Curly-leaf pondweed
Reed canary grass
Small bladderwort
*
*
Common waterweed
Small duckweed
Northern water-milfoil
Coontail
Sago pondweed
Muskgrasses
Small pondweed
Flat-stem pondweed
Nitella
**
0
Leafy pondweed
Frequency of Occurrence (%)
35
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
87
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
35.0
Floristic Quality Index (FQI) Values
30.0
25.0
20.0
15.0
10.0
24.5
24.8
6/30/2014
6/23/2015
19.5
5.0
0.0
6/28/2013
Figure 61
2013–2015 Sunfish Lake Floristic Quality Index (FQI) Values
To:
From:
Subject:
Date:
Page:
Project:
c:
VBWD Managers
Meg Rattei
VBWD June 2014 Point-Intercept Macrophyte Surveys
October 1, 2015
88
23820405
John Hanson, Susannah Torseth, Ray Roemmich, Melissa Imse
1.00
Simpson Diversity Index Values
0.80
0.60
0.90
0.90
0.89
6/28/2013
6/30/2014
6/23/2015
0.40
0.20
0.00
Figure 62
2013–2015 Sunfish Lake Simpson Diversity Index Values