OTREC-RR-11-19

OTREC-RR-11-19Streambeds provide for the necessary habitats and spawning cycles of a healthy fish population. Oregon law requires underwater hydraulic structures to provide proper fish passage. Increasingly stringent regulations apply to fish passageways, and designers must consider a range of flows to accommodate fish movement and avoid structural failure. Fish passages, culverts or bridges, are built where roads cross streambeds. Roughened channels technique re

Streambeds provide for the necessary habitats and spawning cycles of a healthy fish population. Oregon law requires underwater hydraulic structures to provide proper fish passage. Increasingly stringent regulations apply to fish passageways, and designers must consider a range of flows to accommodate fish movement and avoid structural failure. Fish passages, culverts or bridges, are built where roads cross streambeds. ÒRoughened channelsÓ technique re-creates streambeds with the hydraulics necessary for adequate fish passage. This report examines long-term success factors for implementation of fish passageways, especially in the construction phase, and examines whether failures are due to inadequate range and mix of material gradation; unexpected water velocity; or inadequate mixing or compaction of materials during construction. Other factors may include the relationship of downstream slope to structure slope, well-graded fine soil materials in channel fill, and frequent site visits.