Stream crossings, where roads and railroads cross rivers and streams, are frequently unseen barriers to the movement of fish and other species. The most common culprits are culverts, pipes that serve as conduits for rivers under roads and railroads.
Culverts often become barriers because they are perched above the riverbed, or they have flow that is too shallow or too swift for fish movement. American Rivers focuses on policy efforts to improve culvert installation and replacement across the country.
Example Road-Stream Crossing State Policies that Support Aquatic Organism Passage