Barrie Creeks, Lovers Creek, and Hewitt's Creek Subwatershed Plan

The Barrie Creeks, Lovers Creek and Hewitt’s Creek Subwatershed Plan
The short period of record at Hotchkiss and Hewitt’s Creek does not allow for trend analysis. As
previously mentioned, water quality data for Hotchkiss Creek and Hewitt’s Creek have been
collected only since 2008. While this data set is not yet long enough to examine for trends, it is
compared to water quality guidelines for a number of parameters, along with the same time
period for Lovers Creek. Figure 3-4 shows the phosphorus concentrations on these two systems
are slightly higher than Lovers Creek with fewer samples complying with the PWQO. The
highest concentrations are recorded at Hotchkiss Creek, which is located in an intensely
developed subwatershed and, due to the age of the development, there are relatively few
stormwater controls on this particular system to mitigate stormwater runoff quality and quantity.
Because the vast majority of the Hotchkiss catchment is comprised of urban landuses (and in
turn impervious surfaces), the creek has been observed to react very quickly to rain events,
making it very difficult to capture runoff events. It is expected that as the period of record
increases for Hotchkiss, and a greater number of runoff events are captured, the spread of the
data will increase along with the high end concentrations.
Hotchkiss Creek
Hewitts Creek
Lovers Creek
0.00 0.05 0.10 0.15 0.20 0.25 0.30
PWQO = 0.03mg/L
mg/L
Figure 3-4: Lovers, Hewitt’s, and Hotchkiss Creek phosphorus concentrations 2008 – 2010 (mg/L).
3.2.3.2. Chloride
The Canadian Environmental Protection Act has defined road salts containing chloride as toxic
(2001). This was based on research that found that the large amount of road salts being used
can negatively impact ground and surface water, vegetation, and wildlife. While elevated
chloride levels are primarily found around urban centres, chloride levels have been found to be
steadily increasing across the Lake Simcoe watershed, and throughout Ontario, including
waters that could be considered pristine northern rivers (LSRCA, 2007) as well as in Lake
Simcoe itself (Eimers and Winter, 2005).
While Lovers Creek does not show exceedances of the acute toxicity guideline of 586 mg/L,
33% of 2006 – 2010 samples exceed the long term exposure guideline (Table 3-3). As Figure
3-5 shows, the rapidly increasing trend at Lovers Creek likely means the number of samples
exceeding the acute toxicity guideline will likely increase and chloride will increasingly become a
limiting factor on ecosystem health for this system.
Chapter 3: Water Quality – Surface and Groundwater 87