Delph Creek Fish Passage Improvement Project – CRBC

Delph Creek at Porter Road Fish Passage Improvement Project

Project Summary

This project addressed the problem of two, 4-foot metal culverts on Delph Creek at RM 4.7 (13.7 miles from Clackamas River) that were complete barriers to juvenile fish passage and a partial barrier to adult fish passage. Passage was impaired due to a shallow downstream pool, 3.8% slope of the culverts and a 2 foot drop at the culverts’ outlet. These factors also increased stream sediment loading caused by flood waters crossing over Porter Road during high water events, creating additional safety hazards to the traveling public and neighboring private properties.

The culverts under Porter Road were removed, a full-spanning 38 foot long pre-cast modular concrete bridge was installed, and in-stream and riparian habitats were improved. The bridge is 1.5 times bank full stream width and was designed to pass a 100-year storm event.
Completion of this project opened approximately 4.5 miles of high quality spawning and rearing habitat to winter steelhead, Coho salmon, and cutthroat trout. It alleviated road flooding and sediment loading. The project also included invasive species removal and revegetation around the new bridge.