Phosphorus and the Kawartha Lakes - Lakefield Herald

Results
Although the Kawartha Lakes watershed has a relatively low phosphorus loading
potential when compared to the majority of southern Ontario, Figure 3.1, it is unique in
that it has an altered waterway (permanently flooded historical flood plain) with which to
concentrate its nutrient loading. The 31 quaternary watersheds had percent cropland
classes between 1 and 3, and BFI classes between 4 and 8. This resulted in a range of
phosphorous susceptibility index values from 1 to7. Comparable to the land classification
results in chapter 2, we see a distinct separation along the chain of lakes, with low
phosphorus loading potential to the north and high loading potential to the south (Figure
3.2). This model predicts that the southern watersheds will contribute more phosphorus
to the Kawartha Lakes than the northern watersheds.
Take Home Message
This model should be interpreted with caution as it does not take into account
other morphological variables (i.e. shallow lakes, drainage basin ratio) that may
compound the phosphorus loading issue. Although there are many factors that can
contribute phosphorus to a watershed; sewage treatment plants, aerial deposition, faulty
septic systems and animal feces (beef, poultry, hog operations and large populations of
geese and zebra mussels), clearly arable land plays an important component in elevating
phosphorus concentrations in water bodies.
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