At GMRC, we developed a high-resolution technology to identify culverts in watersheds for all Strahler stream orders (including short-lived watercourses of 1st order). In 2019, we were able to develop an approach in the Restigouche watershed in New Brunswick, with available LiDAR data and funding from the ASCF. In Gaspésie, was made available in May 2021.

With LiDAR data, one can develop an elevation numeric model of extreme precision. We can then create a new hydrographic model (more precise than current hydrolines). All water crossings (bridges, fords and culverts) are identified with an automated method. We then classified the culverts slope and identified perched culverts which act as a barrier for fish passage. This enables us to create a full geodatabase of prioritized sites with local partners for compensation and habitat restoration and environmental monitoring projects.

In all, we were able to carry out a full census of crossings for all of Gaspésie: 9,826 total crossings. Approximately, 20 to 30% of the culverts were deemed impassable for fish. We will continue to work with local partners to prioritize these remediation efforts.

Link to webinar: https://www.youtube.com/watch?v=d8Q5kISYc9k