by Adam Sherry, MCG GIS Technician
Culverts are structures designed to allow the flow of water to pass underneath a man-made structure such as a road. Unfortunately, through weathering, improper installation or debris build up, culverts can become barriers to fish migration. In the summer and fall of 2014, MCG took to the streams in the Stewiacke watershed and surrounding MCG Communities, to assess culverts as they relate to Atlantic salmon migration.
There are over 1000 potential water crossings in the Stewiacke Watershed and this summer we were able to visit over 150 of them, giving 75 full assessments. In addition, we were able to visit another 85 potential migration barriers near our MCG member Communities, completing full assessments on 60 of them.
A full assessment involves the collection of stream measurements, culvert measurements, as well as several elevations from specific points along the stream and culvert, which allows us to calculate key characteristics such as outflow drop and slope of the culvert. The combination of these factors, along with debris build up, is the primary features that can result in a barrier to fish migration.
After the assessment, each culvert was rated as a full barrier, a partial barrier or a non-barrier to the migration of Atlantic salmon. We have performed debris removal remediation for five (5) culverts in order to improve fish passage. A list of complete barriers has been compiled, and will be shared with the proper departments of government for suggested remediation, as well as the Clean Annapolis River Project.
As another fun way to share our data, MCG created a Fish Barrier web-tool. In this web application, the user selects an assessed culvert (or enters the parameters they collected for a culvert of their own) to see if our friend Plamu can get through the culvert. You can check it out by clicking on this link: Go, Plamu. GO!
If you are interested in our findings, you can check out the report here: MCG Report: Barriers to Atlantic Salmon Migration
Questions about culverts? Contact Adam Sherry.