INVENTORYING AND PRIORITIZING FISH PASSAGE BARRIER REPLACEMENTS

Tens of thousands of miles of streams flow throughout the State of Maine. Most of these streams are intersected by a network of thousands of miles of roads crossing over bridges and culverts. Culverts at road-stream crossings have the potential to limit the movement of fish just as much as dams and both can have a significant impact on natural processes. In order to reconnect riverine habitats for many aquatic and terrestrial species across Maine, efforts are underway to survey and remove barriers to their movement.

Replacement and upgrading of culverts that are barriers to fish passage can be very costly. To effectively restore fish passage, mangers of road systems not only need to know which crossings are blocking passage but where to target resources so that maximum habitat benefit can be obtained from each replacement. This project developed a Maine Road-Stream Crossing Survey protocol that was used by Maine Forest Service field crews and volunteers to survey over 1000 road crossings in the lower and mid Penobscot River watershed to assess barriers to fish passage. Field data was imported to an ESRI Personal Geodatabase (a spatially aware Microsoft Access database) as a table, and then reformatted and edited to correct errors and make records consistent. Based on field and other data sources, crossings were rated as severe barriers, moderate barriers or adequate fish passage crossings. Barriers were then prioritized for removal based on their position in the stream (the lowest barrier on the stream was considered highest priority), the potential length stream that would be restored by barrier removal and whether the stream supported diadromous fish habitat. An atlas with all surveyed sites and barrier rankings was produced and priority data were provided to towns in the survey area.