The City of Kingston retained Dillon to complete technical assessment and engineering design of turtle crossing mitigation measures along Princess Street and Creekside Valley Road in the vicinity of Collins Creek in Kingston, Ontario, in order to support their strategic plan’s commitment to protect wetlands and the vulnerable wildlife that occupy them.
As part of this strategy, the Dillon team considered the existing municipal infrastructure along Princess Street, the proposed Creekside Valley Road and residential subdivision, additional new culverts or crossing structures (eco‑passages) for turtles, and wildlife exclusion fencing design for the site and the target wildlife species. Another consideration was the strategic placement of turtle nesting mounds designed and constructed to offset the loss of turtle nesting habitat in the road embankment. Furthermore, the strategic plan considered the capital cost required to install the mitigation measures as well as the projected maintenance obligations assumed by the City.
Dillon partnered with Eco-Kare International, who completed a post‑construction monitoring program which was designed to track the efficacy of the engineered mitigation measures and installed turtle nesting habitats. The monitoring study was implemented in 2022 and generated information that will be a valuable addition to road ecology/wildlife mitigation guidelines being developed by Environment and Climate Change Canada (ECCC).
The monitoring study was designed to also evaluate whether constructed nesting mounds can effectively compensate for the loss of road shoulder nesting sites. A total of 12 artificial turtle nesting mounds were distributed along Princess Street and Creekside Valley Road. The study design assessed turtle use of the nesting mounds. Once sufficient multi-year data is collected, hatchling emergence will be assessed to measure breeding success at these sites.
Nesting surveys occurred twice daily from May 29‑June 21, 2022. The efficacy of 2,486 m of wildlife exclusion fencing at reducing road mortality and use of the ACO Tunnel eco-passage and 1200mm high‑density polyethylene (HDPE) culvert along Creekside Valley Road was also evaluated. Princess Street and Creekside Valley Road were driven regularly during each nesting, predation and turtle hatchling emergence survey, to evaluate success.
The Collins Creek Wildlife Mitigation Project has the potential to address major gaps in studies and research, specifically pertaining to the planning and feasibility of turtle crossing and artificial nesting structures. The following investigations were conducted during the mitigation strategy development phase:
- Background review of roads, bridges, culverts, land use, dominant vegetation, baseline habitat features and subdivision
- Road ecology literature review to compare available nesting habitat design research and turtle mitigation best practices to inform the crossing structure and fencing selection process, nesting mound design options and overall design layout of the wildlife mitigation measures
- Site-specific turtle road mortality and nesting was investigated to determine the spatial distribution of known nesting locations and evidence of turtle crossing routes
- Overview of drainage patterns within the study area along with turtle data informed the crossing structure and nesting mound placement process
- A site investigation evaluated turtle movement pathways and confirmed site drainage, and identified the preferred location(s) for turtle nesting habitat, wildlife exclusion fencing and eco-passage(s).
The project was successful due in large part to addressing site-specific and target species-specific complexities such as drainage, flooding and ground elevation considerations, property availability, and turtle migration and movement.
*Images courtesy of Eco-Kare International & City of Kingston
- Association of Consulting Engineering Companies Ontario, Sustainable Development Impact Award, 2023