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ake Partner Program
volunteers collected water samples and water clarity
observations at 54 locations throughout Lake of the Woods in
2003. Information was also collected at 74 other locations in
the Lake of the Woods area including many new locations in
Rainy Lake and along the Rainy River. For the second year,
the Lake Partner samples were analysed at the Dorset
Environmental Science Centre laboratory. Again this year,
data prior to 2002 have been averaged to produce a single,
long-term average. This number is reported together with
the individual results from 2002 and 2003 (see Table 1).
Annual water clarity observations (Secchi depths) are shown as
average values for each year (see Table 2).
Past uncertainties about the current
concentrations of total phosphorus in Lake of the Woods are
now beginning to disappear. Seasonal patterns and ranges in
concentrations are now clearly demonstrated by the data that
has been collected by volunteers over the past two years
(Figure 1). These data can be used in conjunction with
additional data being collected by the MNR fisheries
assessment unit to assess the water quality of Clearwater Bay
and to support other programs being conducted by the Ministry
of the Environment, Inland lakes Group to examine trends
through time in the phosphorus concentrations of Lake of the
Woods using paleolimnology techniques.
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Figure 1. Seasonal, total phosphorus concentrations in
Mud Portage Bay, off Clearwater Bay, Lake of the Woods. |
Comparing 2002 and 2003 Data
A quick look at the data will reveal that there are some
locations that show relatively large differences between 2002
and 2003. Also, concentrations were generally lower in 2003
(Figure 2). Large, between-year differences make it difficult
to interpret trends through time and require more years of
data to establish long-term, mean values for a given
location. After a few more years of data have been collected
we will understand both the current trophic status of the lake
and have some idea also about the variation between years
that can be expected.
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Figure 2. Differences in TP concentrations between
2002 and 2003 in Lake of the Woods. |
Monthly Sample Collection in Lake of the Woods
Locations that were sampled monthly in Lake of the Woods
showed TP concentrations and patterns for 2003 that were the
similar to those
measured in 2002. One thing to note about the 2003 monthly
data is that on several occasions when the volunteers sampled
late into the season
(Oct, Nov) the values observed were the highest values
observed for the year (Figure3). This would indicate that it
is very important to collect the
late fall samples since they represent the highest seasonal
values for some locations. These monthly data are extremely
valuable and support the
other projects mentioned earlier.
The Rainy River is an important source of water
and phosphorus to Lake of the Woods. Consequently monthly
sample locations were
established for 2003 in Rainy Lake and along the Rainy River.
These data will help to assess the role of the Rainy River in
the TP budget of
Lake of the Woods.
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Figure 3.
Seasonal, total phosphorus concentrations at Frenchman’s
Rock, Lake of the Woods. Red circles show 2002 data,
green circles are 2003 data. Note that highest
concentrations are at the end of the season |
Summary
The Lake Partner Program volunteers should be commended for
collecting a valuable set of high-quality, defensible data.
It is clear that the results
will be useful to the ongoing limnological projects in Lake of the Woods.
These data would be difficult to collect without the help of
volunteers.
Furthermore, it would be impossible to contact and organize
volunteers in the Lake of the Woods area without the support
and direction of the Lake
of the Woods District Property Owners Association.
 Click
to enlarge
Figure 4. Map showing 2003 Lake Partner sample
locations. Purple squares indicate sites where monthly samples
were taken.
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