Bronte Creek Rehabilitation

Lowville Park is considered one of Halton Region’s premier locations for public use and opportunities to see migratory salmonids spawning. This section of Bronte creek had gradually been impacted from increased runoff, public use along banks and instream changes (i.e., channel widening). The impacts to water quality from an increased bank width and limited depth relate to thermal changes and limited depth for cold water species use. Increased temperatures degrade water quality and in turn reduce the species diversity of invertebrates (i.e., food for fish).

Burnside was retained to develop natural channel design options and prescriptions for areas that have been impacted by erosion, heavy pedestrian use, and channel widening. We completed spawning surveys for Rainbow trout (steelhead) and Chinook salmon to determine critical habitat areas to be protected during construction, based on multi-seasonal use. Habitat prescriptions included an overall channel width reduction, bank stabilization using willow matts and river stone, creation of spawning areas, riffle sections, boulder clusters, large woody debris, pool creation, off-channel juvenile habitat, and retrofit of existing riffle structures.

We also conducted swim-up counts for Steelhead fry and determined prescription success based on the natural channel design and rehabilitation works. This project has been reviewed for success over the past 10 years and Trout Unlimited was overwhelmed with the positive feedback on the design and construction.

It was noted by Trout Unlimited that Brook trout historically existed in this reach of the creek, although they have not been observed in over 50 years. Based on fish sampling post-construction, the first “Young of the Year” Brook trout was captured by Trout Unlimited and temperature improvements (i.e., colder on average) were observed.