This thesis presents the findings of a physical modeling study examining the hydraulic characteristics within the inlet region of a corrugated steel pipe (CSP) culvert with common inlet treatments. Also examined are the effects of embedding the culvert below the stream bed and backfilling the culvert with granular material.

Velocity and turbulence distributions were examined in an effort to better understand how these inlet treatments may affect fish passage. The velocity field of each inlet configuration was dominated by a central jet of high velocity surrounded by low velocity boundary areas. Based on percent area analysis the various projecting end inlet configura-tions presented the largest area with streamwise velocities less than Uavg. The usefulness of the low velocity boundary areas may be limited by significant vertical and spanwise velocities and associated elevated turbulence levels.