TRB’s National Cooperative Highway Research Program (NCHRP) Report 734: Hydraulic Loss Coefficients for Culverts explores culvert designs that maintain natural velocities and minimize turbulence to allow migratory species to pass through the culvert barrel.

The report describes the refinement of existing hydraulic relationships and the development of new ones for analysis and design of culverts for conventional and nontraditional, environmentally sensitive installations.